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Sample records for nickelii copperii zincii

  1. Modeling of copper(II) and zinc(II) extraction from chloride media with Kelex 100

    SciTech Connect

    Bogacki, M.B.; Zhivkova, S.; Kyuchoukov, G.; Szymanowski, J.

    2000-03-01

    The extraction of copper(II) and zinc(II) from acidic chloride solutions with protonated Kelex 100 (HL) was studied and the extraction isotherms were determined for systems containing individual metal ions and their mixtures. A chemical model was proposed and verified. It considers the coextraction of the following species: MCl{sub 4}(H{sub 2}L){sub 2}, MCl{sub 4}(H{sub 2}L){sub 2}{center_dot}HCl, MCl{sub 3}(H{sub 2}L), ML{sub 2}, and H{sub 2}L{center_dot}HCl. Zinc(II) is extracted as the metal ion pairs, while copper(II) can be extracted as the metal ion pair and the chelate. The model can be used to predict the effect of experimental conditions on extraction and coextraction of the metal ions considered.

  2. G-quadruplex vs. duplex-DNA binding of nickel(II) and zinc(II) Schiff base complexes.

    PubMed

    Bonsignore, Riccardo; Terenzi, Alessio; Spinello, Angelo; Martorana, Annamaria; Lauria, Antonino; Almerico, Anna Maria; Keppler, Bernhard K; Barone, Giampaolo

    2016-08-01

    Novel nickel(II) (1) and zinc(II) (2) complexes of a Salen-like ligand, carrying a pyrimidine ring on the N,N' bridge, were synthesized and characterized. Their interaction with duplex and G-quadruplex DNA was investigated in aqueous solution through UV-visible absorption, circular dichroism and viscometry measurements. The results obtained point out that, while the zinc(II) complex does not interact with both duplex and G-quadruplex DNA, the nickel(II) complex 1 binds preferentially to G-quadruplex respect to duplex-DNA, with values of the DNA-binding constants, Kb, 2.6×10(5)M(-1) and 3.5×10(4)M(-1), respectively. Molecular dynamics simulations provided an atomic level model of the top-stacking binding occurring between 1 and hTelo (a 22-mer sequence oligonucleotide) in G-quadruplex conformation. PMID:27230387

  3. Calorimetric and spectroscopic studies of solutions of copper(II) and nickel(II) nitrates in water-carbamide mixtures at 298.15 K

    NASA Astrophysics Data System (ADS)

    Vandyshev, V. N.

    2008-06-01

    The heat effects of mixing aqueous solutions of copper(II) and nickel(II) nitrates with water-carbamide mixtures were measured on an isothermic-shell calorimeter in the amide concentration region. An increase in the concentration of carbamide strengthened solvation in copper(II) salt solutions to a greater extent. The electronic absorption spectra were recorded at fixed concentrations of the electrolytes to find that the solvation of copper(II) and nickel(II) nitrates in water-carbamide mixtures involved intrasphere and predominantly outer-sphere cation-solvent interactions, respectively.

  4. The computed distribution of copper(II) and zinc(II) ions among seventeen amino acids present in human blood plasma

    PubMed Central

    Hallman, P. S.; Perrin, D. D.; Watt, Ann E.

    1971-01-01

    The equilibrium distribution of copper(II) and zinc(II) ions among a mixture of 17 amino acids has been computed from stability-constant and blood-plasma-composition data. At pH7.4, 98% of the copper(II) in the simulated plasma solution is co-ordinated to histidine and cystine, predominantly as the mixed-ligand complexes [Cu·His·Cystine]− and [Cu·H·His·Cystine]. Approximately half of the zinc(II) is co-ordinated to cysteine and histidine, but appreciable complex-formation occurs with most of the other amino acids. Stability constants are given for copper(II) and zinc(II) amino acid complexes, including some mixed-ligand species, at 37°C and I=0.15m. PMID:5119792

  5. Structural characterization of some oxalato-bridged copper(II) and nickel(II) complexes

    NASA Astrophysics Data System (ADS)

    Mautner, Franz A.; Louka, Febee R.; Massoud, Salah S.

    2009-03-01

    A new series of dinuclear oxalato-bridged copper(II) and nickel(II) complexes derived from tridentate amines: [Cu 2(Medpt) 2(μ-C 2O 4)](ClO 4) 2 ( 1), [Cu 2(pmedien) 2(μ-C 2O 4)](ClO 4) 2 ( 2), [Cu 2(DPA) 2(μ-C 2O 4)(ClO 4) 2]·2H 2O (3), and [Ni 2(Et 2dien) 2(μ-C 2O 4)(H 2O) 2](ClO 4) 2·2H 2O ( 4) (C 2O 42- = oxalate dianion, Medpt = 3,3'-diamino- N-methyldipropylmine, pmedien = N, N, N', N'', N''-pentamethyldiethylenetriamine, DPA = di(2-pyridylmethyl)amine and Et 2dien = N, N-diethyldiethylenetriamine) were synthesized and structurally characterized by X-ray crystallography. The spectral and structural characterizations of these complexes are reported. In this series, structures consist of the C 2O 42- bridging the two M(II) centers in a bis-bidentate bonding mode. The Cu 2+ centers are coordinated to the tridentate amines Medpt or pmedien in distorted SP geometry in 1 and 2, respectively, with the ClO 4- groups as counter ions. In the other two complexes, distorted octahedral geometries were achieved by the three nitrogen donors of the DPA and by an oxygen atom from coordinated perchlorate ion in 3 and by the Et 2dien and one water molecule in 4.

  6. Polynuclear and mixed-ligand complexes of copper(II) and nickel(II) with (1-hydroxyethylidene)bisphosphonic acid

    SciTech Connect

    Amirov, R.R.; Saprykova, Z.A.

    1987-12-20

    The compositions and stabilities of heteronuclear and mixed-ligand copper(II) and nickel(II) (1-hydroxyethylidene)bisphosphonates were determined. Parameters of the compatibility of the ligands and central ions in the complexes were calculated. It was shown that the monoprotonated anion of (1-hydroxyethylidene)bisphosphonic acid is capable of terdentate coordination with the participation of the alcoholic hydroxy group. The acidities of the solutions were determined on a pH-673 meter. The spin-lattice relaxation time was measured on a pulse NMR spectrometer.

  7. Synthesis and crystal structure of thiosemicarbazide complexes of nickel(II) and copper(II)

    NASA Astrophysics Data System (ADS)

    Sadikov, G. G.; Antsyshkina, A. S.; Koksharova, T. V.; Sergienko, V. S.; Kurando, S. V.; Gritsenko, I. S.

    2012-07-01

    Thiosemicarbazide complexes of nickel(II) [Ni( TSC)2](H Sal)2 ( I) and copper(II) [Cu( TSC)2](H Sal)2 ( Ia) ( TSC is thiosemicarbazide and H Sal is a salycilate anion), as well as complexes [Ni( TSC)2](SO4) · 2H2O ( II) and [Ni( TSC)3]Cl2 · H2O ( III), are synthesized and characterized by IR spectroscopy and X-ray diffraction. Monoclinic crystals I and Ia are isostructural; space group P21/ n, Z = 2. Crystals II are monoclinic, space group P21/ m, Z = 2. Crystals III are orthorhombic, space group Pbca, Z = 8. In I and Ia, two planar salycilate anions sandwich a planar centrosymmetric [Ni( TSC)2]2+ cation to form a supermolecule. The cation and anions are additionally bound by hydrogen bonds. Other hydrogen bonds connect supermolecules into planar layers. In structure II, centrosymmetric [Ni( TSC)2]2+ cations are connected by π-stacking interactions into supramolecular ensembles of a specific type. The ensembles, water molecules, and (SO4)2- anions are bound in the crystal via hydrogen bonds. In the [Ni( TSC)3]2+ cation of structure III, ligands coordinate the Ni atom by the bidentate chelate pattern with the formation of five-membered metallocycles. These metallocycles have an envelope conformation unlike those in I and II, which are planar. In III (unlike in analogous complexes), a meridional isomer of the coordination octahedron of the Ni atom is formed. Together with Cl1- and Cl2- anions, cations form supermolecules, which are packed into planar layers with a square-cellular structure. The layers are linked by hydrogen bonds formed by crystallization water molecules that are located between the layers.

  8. Copper(II) and nickel(II) complexes of beta-aminoketoxime ligand: syntheses, crystal structures, magnetism, and nickel(II) templated coupling of oxime with nitrile.

    PubMed

    Das, Oindrila; Adarsh, N N; Paul, Ankan; Paine, Tapan Kanti

    2010-01-18

    The syntheses, molecular structures, and magnetic properties of a dicopper(II) complex, [Cu(2)(HL(1))(2)](ClO(4))(2) (1), and its nickel(II) analog, [Ni(2)(HL(1))(2)](ClO(4))(2) (2), of a beta-amino ketoxime ligand (H(2)L(1) = 4,4,9,9-tetramethyl-5,8-diazadodecane-2,11-dione dioxime) are discussed. The metal centers in out-of-plane oximate bridged dinuclear complexes (1 and 2) display distorted trigonal bipyramidal geometry and form a six-membered M(2)(NO)(2) ring oriented in a boat conformation. The two copper(II) centers in 1 interact ferromagnetically giving rise to a triplet-spin ground state whereas the two nickel(II) centers in 2 interact antiferromagnetically to stabilize a singlet-spin state. Variable temperature magnetic susceptibility measurements establish the presence of a weak ferromagnetic coupling (J = 13 cm(-1)) in 1 and a weak anitiferromagnetic coupling (J = -12 cm(-1)) in 2. The exchange coupling constant derived from B3LYP computations in conjunction with broken symmetry spin-projection techniques for the oximate bridged dinuclear copper(II) complex shows excellent agreement with the corresponding experimental value. A square-planar mononuclear nickel(II) complex of the dioxime ligand, [Ni(H(2)L(1))](ClO(4))(2) (3), is reported along with its crystal structure, which reacts with acetonitrile to produce a six-coordinate mononuclear complex, [Ni(L(2))](ClO(4))(2) (4). The ligand (L(2)) in complex 4 is the iminoacyl derivative of oxime, where the coupling of oxime and acetonitrile takes place via a proton-assisted pathway. The iminoacylation of H(2)L(1) works with other nitriles like butyronitrile and benzonitrile. Computational studies support a proton-assisted coupling of oxime with nitrile. The critical transition states have been located for the iminoacylation reaction. Complex 4 can be converted back to complex 3 by reacting with sodium acetate in methanol. PMID:20025254

  9. New dinuclear copper(II) and zinc(II) complexes for the investigation of sugar-metal ion interactions.

    PubMed

    Bera, Manindranath; Patra, Ayan

    2011-10-18

    We have studied the binding interactions of biologically important carbohydrates (D-glucose, D-xylose and D-mannose) with the newly synthesized five-coordinate dinuclear copper(II) complex, [Cu(2)(hpnbpda)(μ-OAc)] (1) and zinc(II) complex, [Zn(2)(hpnbpda)(μ-OAc)] (2) [H(3)hpnbpda=N,N'-bis(2-pyridylmethyl)-2-hydroxy-1,3-propanediamine-N,N'-diacetic acid] in aqueous alkaline solution. The complexes 1 and 2 are fully characterized both in solid and solution using different analytical techniques. A geometrical optimization was made of the ligand H(3)hpnbpda and the complexes 1 and 2 by molecular mechanics (MM+) method in order to establish the stable conformations. All carbohydrates bind to the metal complexes in a 1:1 molar ratio. The binding events have been investigated by a combined approach of FTIR, UV-vis and (13)C NMR spectroscopic techniques. UV-vis spectra indicate a significant blue shift of the absorption maximum of complex 1 during carbohydrate coordination highlighting the sugar binding ability of complex 1. The apparent binding constants of the substrate-bound copper(II) complexes have been determined from the UV-vis titration experiments. The binding ability and mode of binding of these sugar substrates with complex 2 are indicated by their characteristic coordination induced shift (CIS) values in (13)C NMR spectra for carbon atoms C1, C2, and C3 of sugar substrates. PMID:21764045

  10. Solvent effects on the stability of nifuroxazide complexes with cobalt(II), nickel(II) and copper(II) in alcohols.

    PubMed

    Khan, Mustayeen A; Ali, S Kauser; Bouet, Gilles M

    2002-05-21

    A spectrophotometric study of the complexation of nifuroxazide with cobalt(II), nickel(II) and copper(II) was carried out in different alcohols. The formation of a complex in each case is reported and their stability constants have been calculated. For a given solvent, the stability of the complexes increases from cobalt to copper. In the case of copper(II), the stability varies as an inverse function of the dielectric constant of the solvent. A possible structure of the complex is proposed. PMID:12009257

  11. Spectroscopic characterization, antioxidant and antitumour studies of novel bromo substituted thiosemicarbazone and its copper(II), nickel(II) and palladium(II) complexes

    NASA Astrophysics Data System (ADS)

    Jagadeesh, M.; Lavanya, M.; Kalangi, Suresh K.; Sarala, Y.; Ramachandraiah, C.; Varada Reddy, A.

    2015-01-01

    A new, slightly distorted octahedral complex of copper(II), square planar complexes of nickel(II) and palladium(II) with 2,4‧-dibromoacetophenone thiosemicarbazone (DBAPTSC) are synthesized. The ligand and the complexes are characterized by FT-IR, FT-Raman, powder X-ray diffraction studies. The IR and Raman data are correlated for the presence of the functional groups which specifically helped in the confirmation of the compounds. In addition, the free ligand is unambiguously characterized by 1H and 13C NMR spectroscopy while the copper(II) complex is characterized by electron paramagnetic resonance spectroscopy (EPR). The g values for the same are found to be 2.246 (g1), 2.012 (g2) and 2.005 (g3) which suggested rhombic distortions. The HOMO-LUMO band gap calculations for these compounds are found to be in between 0.5 and 4.0 eV and these compounds are identified as semiconducting materials. The synthesized ligand and its copper(II), nickel(II) and palladium(II) complexes are subjected to antitumour activity against the HepG2 human hepatoblastoma cell lines. Among all the compounds, nickel(II) complex is found to exert better antitumour activity with 57.6% of cytotoxicity.

  12. Spectroscopic characterization, antioxidant and antitumour studies of novel bromo substituted thiosemicarbazone and its copper(II), nickel(II) and palladium(II) complexes.

    PubMed

    Jagadeesh, M; Lavanya, M; Kalangi, Suresh K; Sarala, Y; Ramachandraiah, C; Varada Reddy, A

    2015-01-25

    A new, slightly distorted octahedral complex of copper(II), square planar complexes of nickel(II) and palladium(II) with 2,4'-dibromoacetophenone thiosemicarbazone (DBAPTSC) are synthesized. The ligand and the complexes are characterized by FT-IR, FT-Raman, powder X-ray diffraction studies. The IR and Raman data are correlated for the presence of the functional groups which specifically helped in the confirmation of the compounds. In addition, the free ligand is unambiguously characterized by (1)H and (13)C NMR spectroscopy while the copper(II) complex is characterized by electron paramagnetic resonance spectroscopy (EPR). The g values for the same are found to be 2.246 (g1), 2.012 (g2) and 2.005 (g3) which suggested rhombic distortions. The HOMO-LUMO band gap calculations for these compounds are found to be in between 0.5 and 4.0 eV and these compounds are identified as semiconducting materials. The synthesized ligand and its copper(II), nickel(II) and palladium(II) complexes are subjected to antitumour activity against the HepG2 human hepatoblastoma cell lines. Among all the compounds, nickel(II) complex is found to exert better antitumour activity with 57.6% of cytotoxicity. PMID:25064500

  13. Nickel(II) and zinc(II) dibenzoylmethanates: molecular and crystal structure, polymorphism, and guest- or temperature-induced oligomerization.

    PubMed

    Soldatov, D V; Henegouwen, A T; Enright, G D; Ratcliffe, C I; Ripmeester, J A

    2001-03-26

    Four forms of nickel(II) and two of zinc(II) dibenzoylmethanates have been isolated and characterized with powder and single-crystal X-ray diffraction analyses, differential scanning calorimetry, magnetic susceptibility measurements, and solid-state 13C cross-polarization/magic angle spinning NMR. Nickel dibenzoylmethanate, Ni(DBM)2 (DBM = PhCOCHCOPh-), forms three polymorphic forms (light-green, brown, and green) and a fourth clathrate form with guest benzene included. The light-green polymorph is metastable. Substituted benzenes induce recrystallization of the polymorph into a stable brown form (C30H22NiO4; a = 26.502(3) A, b = 5.774(1) A, c = 16.456(2) A, beta = 116.03(1) degrees; monoclinic, C2/c; Z = 4). Unlike the other forms, the brown form is diamagnetic and is comprised of monomers of the low-spin [Ni(DBM)2] complex. The Ni(II) is chelated by two DBM ligands in a square planar environment by four donor oxygen atoms. When heated, the brown form transforms to a green form which is stable above 202 degrees C (C90H66Ni3O12; a = 13.819(2) A, b = 16.252(2) A, c = 17.358(2) A, beta = 108.28(1) degrees; monoclinic, P2(1)/n; Z = 2). This polymorph is formed by van der Waals packing of trimers [Ni3(DBM)6] containing linear Ni3 clusters with an Ni-Ni distance of 2.81 A. The cluster is surrounded by six DBM ligands, providing a distorted octahedral environment about each Ni by six oxygen atoms. Benzene stabilizes the trimeric structure at room temperature, forming a [Ni3(DBM)6].2(benzene) inclusion compound (Ni-Ni distance of 2.83 A) with guest benzene molecules located in channels (C90H66Ni3O12 + 2(C6H6); a = 17.670(2) A, b = 20.945(3) A, c=11.209(2) A, beta = 102.57(1) degrees; monoclinic, P2(1)/c; Z = 2). Zinc dibenzoylmethanate has been prepared in two polymorphic forms. The monomeric form contains [Zn(DBM)2] molecules with the zinc center in a distorted tetrahedral environment of four oxygens from the two chelated DBMs (C30H22O4Zn; a = 10.288(2) A, b = 10

  14. Functionalized mesoporous silica supported copper(II) and nickel(II) catalysts for liquid phase oxidation of olefins.

    PubMed

    Nandi, Mahasweta; Roy, Partha; Uyama, Hiroshi; Bhaumik, Asim

    2011-12-14

    Highly ordered 2D-hexagonal mesoporous silica has been functionalized with 3-aminopropyltriethoxysilane (3-APTES). This is followed by its condensation with a dialdehyde, 4-methyl-2,6-diformylphenol to produce an immobilized Schiff-base ligand (I). This material is separately treated with methanolic solution of copper(II) chloride and nickel(II) chloride to obtain copper and nickel anchored mesoporous materials, designated as Cu-AMM and Ni-AMM, respectively. The materials have been characterized by Fourier transform infrared (FT-IR) and UV-vis diffuse reflectance (DRS) spectroscopy, powder X-ray diffraction (XRD), transmission electron microscopy (TEM), N(2) adsorption-desorption studies and (13)C CP MAS NMR spectroscopy. The metal-grafted mesoporous materials have been used as catalysts for the efficient and selective epoxidation of alkenes, viz. cyclohexene, trans-stilbene, styrene, α-methyl styrene, cyclooctene and norbornene to their corresponding epoxides in the presence of tert-butyl hydroperoxide (TBHP) as the oxidant under mild liquid phase conditions. PMID:21989952

  15. Nickel(II) and Zinc(II) meso-Tetracyclohexylporphyrins. Structural and Electronic Effects Induced by meso-Cyclohexyl Substitution in Metalloporphyrins.

    PubMed

    Veyrat, Marc; Ramasseul, René; Turowska-Tyrk, Ilona; Scheidt, W. Robert; Autret, Marie; Kadish, Karl M.; Marchon, Jean-Claude

    1999-04-19

    The synthesis and X-ray structures of the zinc(II) and nickel(II) complexes of meso-tetracyclohexylporphyrin H(2)(TCHP) are described. The nonplanarity of the meso substituents results in steric crowding at the porphyrin periphery. In the solid state, the nickel(II) complex Ni(TCHP) has a ruffled porphyrin conformation while Zn(TCHP) exhibits a stepped distortion of the macrocycle. In chloroform solution, fast rotation of the cyclohexyl groups on the NMR time scale is observed at room temperature for both complexes. Temperature-dependent (1)H NMR spectra showed that the (-g,g,-g,g) conformer of Zn(TCHP) and Ni(TCHP) is prevalent in solution at low temperatures and gave an estimate for the rotation barrier of the cyclohexyl groups (DeltaG(c)() = 10-12 kcal mol(-)(1)). In both complexes, the porphyrin ring is easier to oxidize and harder to reduce than in their tetraphenylporphyrin M(TPP) congeners, in agreement with the stronger electron-donating effect of the cyclohexyl group. The magnitude of the potential shift is larger for the first oxidation than for the first reduction, reflecting a smaller HOMO-LUMO energy gap and a greater degree of macrocycle distortion than in the M(TPP) derivatives. This information is of importance to understanding the protein regulation of electron-transfer processes by cytochrome c and other redox active proteins. Crystal data: Ni(TCHP).CHCl(3).CH(3)CN, monoclinic, C2/c, a = 27.405(12), b = 10.004(21), c = 32.877(24) Å, beta = 107.71(3) degrees at 127 K, Z = 8. Zn(TCHP), monoclinic, P2(1)/a, a = 11.159(15), b = 11.992(7), c = 13.465(20) Å, beta = 102.85(16) degrees at 127 K, Z = 2. PMID:11670946

  16. Structural and luminescence studies of nickel(II) and copper(II) complexes with (1R,2R)-cyclohexanediamine derived unsymmetric Schiff base.

    PubMed

    Barwiolek, Magdalena; Szlyk, Edward; Muzioł, Tadeusz M; Lis, Tadeusz

    2011-11-01

    Unsymmetrical Schiff base obtained by the condensation reaction of (1R,2R)(-)cyclohexanediamine with 2-hydroxybenzaldehyde and 2-hydroxynaphthaldehyde was used as a ligand for copper(II) and nickel(II). The ligand and complexes were characterized by circular dichroism (CD), UV-VIS, fluorescence, IR and (1)H (NOE diff), NOESY and (13)C NMR (ligand) spectra. The X-ray crystal structures solved for (1R,2R)(-)chxn(salH)(naftalH) and Cu(II)(1R,2R)(-)chxn(sal)(naftal) revealed tetrahedral distortion of coordination sphere in the solid phase. The [Cu(1R,2R)(-)chxn(sal)(naftal)]·0.5EtOH·1.25H(2)O complex crystallized in the monoclinic chiral C2 space group with two molecules in the asymmetric unit as well as disordered ethanol and water molecules. For both molecules Cu(II) ions were found in square-planar environments and adopts conformation described as "semi-open armed", because of distinctly oriented arms according to cyclohexane ring defined by three torsion angles. The thin layers of the ligands, copper(II) and nickel(II) complexes were deposited on Si(111) by a spin coating method and characterized with scanning electron microscopy SEM/EDS and fluorescence spectra. The ligand layers exhibit the most intensive fluorescence band at 498 nm, which can be assigned to emission transition π* → n of Schiff base ligand. For copper(II) layers the most intensive band from intraligand transition at 550 nm was observed. The highest intensity band was registered for the layer obtained when rotation speed was 1000 rpm and time 20 s. The nickel(II) complex layers fluorescence spectra exhibit an intensive band at 564 nm. The emission maxima of the copper(II) and nickel(II) complexes are shifted towards longer wavelength in comparison to the free ligand layers. CD spectra of the complexes in solution are characteristic for tetrahedral planar distortion of the chelate ring. The (1)H NMR NOE diff were measured and the position of the nearest hydrogen atoms in the cyclohexane and

  17. Synthesis, spectral characterization and biological evaluation of copper(II) and nickel(II) complexes with thiosemicarbazones derived from a bidentate Schiff base

    NASA Astrophysics Data System (ADS)

    Chandra, Sulekh; Bargujar, Savita; Nirwal, Rita; Yadav, Neesha

    2013-04-01

    Complexes of copper(II) and nickel(II) of general composition M(L)2X2, have been synthesized with the ligand 1-Tetralone thiosemicarbazone (where L = 1-Tetralone thiosemicarbazone and X=Cl,1/2SO42-). The molar conductance of the complexes in fresh solution of DMSO lies in the range of 10-20 Ω-1 cm2 mol-1 indicating their non-electrolytic behavior. Thus, the complexes may be formulated as [M(L2)X2]. Ligand was characterized by mass, NMR, IR and single crystallographic studies. All the complexes were characterized by elemental analyses, magnetic moments, IR, electronic and EPR spectral studies. The IR spectral data of ligand indicated the involvement of sulfur and azomethine nitrogen in coordination to the central metal ion. The copper(II) and nickel(II) complexes were found to have magnetic moments1.93-1.96 BM and 2.91-2.94 BM corresponding to one and two unpaired electrons respectively. On the basis of molar conductance, EPR, electronic and infrared spectral studies, a tetragonal geometry has been assigned for Cu(II) chloride complex and trigonal bipyramidal to Cu(II) sulfate complex but an octahedral geometry for Ni(II) complexes. Newly synthesized ligand and its Cu(II) and Ni(II) complexes have also been screened against different bacterial and fungal species.

  18. Cadmium(II), nickel(II), and zinc(II) complexes of vacataporphyrin: a variable annulene conformation inside a standard porphyrin frame.

    PubMed

    Pacholska-Dudziak, Ewa; Skonieczny, Janusz; Pawlicki, Miłosz; Szterenberg, Ludmiła; Latos-Grazyński, Lechosław

    2005-11-28

    5,10,15,20-Tetraaryl-21-vacataporphyrin, 1 (butadieneporphyrin, annulene-porphyrin hybrid), which contains a vacant space instead of heteroatomic bridge, gives diamagnetic zinc(II) 1-ZnCl and cadmium(II) 1-CdCl and paramagnetic nickel(II) 1-NiCl complexes. A metal ion is bound in the macrocyclic cavity by three pyrrolic nitrogens. Coordination imposes a steric constraint on the geometry of the ligand and leads to two stereoisomers with a butadiene fragment oriented toward 1-MCl-i or outward 1-MCl-o of the macrocyclic center. 1-CdCl-o, 1-ZnCl-o, and the free base share a common 1H NMR spectral pattern as the basic structural features of 1 are preserved after metal ion insertion. The 1H NMR spectra of 1-CdCl-i and 1-ZnCl-i reflect a decrease of aromaticity accounted for by the inverted butadiene geometry. The proximity of the butadiene fragment to the metal ion induces direct couplings between the spin-active nucleus of the metal ((111/113)Cd) and the adjacent 1H nuclei of butadiene. The pattern of chemical shifts detected for isomeric 1-NiCl-i and 1-NiCl-o is typical for high-spin nickel(II) complexes of porphyrin analogues. Resonances 2,3-H of 1-NiCl-o or 1-NiCl-i present the chemical shift typical for the beta-H pyrrolic position despite the vacancy in the location of nitrogen-21. Coordination of imidazole, methanol-d4, acetonitrile-d3, or chloride converts 1-NiCl-i and 1-NiCl-o into distinct species which contain two axial ligands: 1-Ni(Im)2+; 1-Ni(CD3OD)2+; 1-Ni(CD3CN)2+; 1-Ni(Cl)2-. The density functional theory (DFT) has been applied to model the molecular and electronic structure of feasible 1-CdCl stereoisomers. The total energies calculated using the B3LYP/LANL2DZ approach demonstrate a very small energy difference (2.3 kcal/mol) between 1-CdCl-o and 1-CdCl-i stereoisomers consistent with their concurrent formation. PMID:16296834

  19. Synthesis, characterization and X-ray structures of new antiproliferative and proapoptotic natural aldehyde thiosemicarbazones and their nickel(II) and copper(II) complexes.

    PubMed

    Belicchi Ferrari, Marisa; Bisceglie, Franco; Pelosi, Giorgio; Sassi, Monica; Tarasconi, Pieralberto; Cornia, Mara; Capacchi, Silvia; Albertini, Roberto; Pinelli, Silvana

    2002-06-01

    Synthesis and characterization of new thiosemicarbazones derived from natural aldehydes (1-9) have been investigated in order to develop a research program aimed at the development of compounds with antiviral, antibacterial, and antitumor properties. These substances contain both a chain with N and S nucleophilic centers with tuberculostatic activity, and an alkyl or terpenic moiety. In addition, a few nickel(II) and copper(II) complexes (10-18), derived also from the previously studied ligands, were synthesized and characterized by means of NMR and IR techniques. The trans-2-octenal N(1)-phenylthiosemicarbazone and its nickel complex were also characterized by X-ray diffractometry. Biological studies, performed with some of these compounds, have involved both inhibition of cell proliferation and apoptosis tests in vitro on human leukemia cell line U937 to deepen our knowledge on the way these substances interfere with biological processes in leukemic cells. PMID:12031803

  20. Antibacterial, DNA interaction and cytotoxic activities of pendant-armed polyamine macrocyclic dinuclear nickel(II) and copper(II) complexes

    NASA Astrophysics Data System (ADS)

    Arthi, P.; Haleel, A.; Srinivasan, P.; Prabhu, D.; Arulvasu, C.; Kalilur Rahiman, A.

    2014-08-01

    A series of dinuclear nickel(II) and copper(II) complexes (1-6) of hexaaza macrocycles of 2,6-diformyl-4-methylphenol with three different benzoyl pendant-arms, 2,2‧-benzoyliminodi(ethylamine) trihydrochloride (L), 2,2‧-4-nitrobenzoyliminodi(ethylamine) trihydrochloride (L‧) and 2,2‧-3,5-dinitrobenzoyliminodi(ethylamine) trihydrochloride (L″) have been synthesized and characterized by spectral methods. The electrochemical studies of these complexes depict two irreversible one electron reduction processes around E1pc = -0.62 to -0.76 V and E2pc = -1.21 to -1.31, and nickel(II) complexes (1-3) exhibit two irreversible one electron oxidation processes around E1pa = 1.08 to 1.14 V and E2pa = 1.71 to 1.74 V. The room temperature magnetic moment values (μeff, 1.52-1.54 BM) indicate the presence of an antiferromagnetic interaction in the binuclear copper(II) complexes (4-6) which is also observed from the broad ESR spectra with a g value of 2.14-2.15. The synthesized complexes (1-6) were screened for their antibacterial activity. The results of DNA interaction studies indicate that the dinuclear complexes can bind to calf thymus DNA by intercalative mode and display efficient cleavage of plasmid DNA. Further, the cytotoxic activity of complexes 2, 5 and 6 on human liver adenocarcinoma (HepG2) cell line has been examined. Nuclear-chromatin cleavage has also been observed with PI staining and comet assays.

  1. Copper(II) and Zinc(II) Complexes of Conformationally Constrained Polyazamacrocycles as Efficient Catalysts for RNA Model Substrate Cleavage in Aqueous Solution at Physiological pH.

    PubMed

    Bím, Daniel; Svobodová, Eva; Eigner, Václav; Rulíšek, Lubomír; Hodačová, Jana

    2016-07-18

    As part of a quest for efficient artificial catalysts of RNA phosphodiester bond cleavage, conformationally constrained mono- and bis-polyazamacrocycles in which tri- or tetraazaalkane chains link the ortho positions of a benzene ring were synthesized. The catalytic activities of mono- and dinuclear copper(II) and zinc(II) complexes of these polyazamacrocycles towards cleavage of the P-O bond in 2-hydroxypropyl-4-nitrophenylphosphate (HPNP) in aqueous solution at pH 7 have been determined. Only the complexes of the ligands incorporating three nitrogen atoms in a macrocycle proved to be capable of efficiently catalyzing HPNP transesterification. The dinuclear complexes were found to be approximately twice as efficient as their mononuclear counterparts, and exhibited Michaelis-Menten saturation kinetics with calculated rate constants of kcat ≈10(-4)  s(-1) . By means of quantum chemical calculations (DFT/COSMO-RS), several plausible reaction coordinates were described. By correlating the calculated barriers with the experimental kinetic data, two possible reaction scenarios were revealed, with activation free energies of 20-25 kcal mol(-1) . PMID:27310481

  2. Excessive Copper(II) and Zinc(II) Levels in Drinkable Water Sources in Areas Along the Lake Victoria Shorelines in Siaya County, Kenya.

    PubMed

    Wambu, Enos W; Omwoyo, Wesley N; Akenga, Teresa

    2016-01-01

    Copper(II) and zinc(II) levels in drinkable water sources in the alluvium areas of the Lake Victoria Basin in Siaya County of Kenya were evaluated to assess the risk posed to resident communities by hydrogeological accumulation of toxic residues in the sedimentary regions of the lake basin. The levels of the metals in water were analyzed by atomic absorption spectroscopy. Metal concentrations ranged from 0.11 to 4.29 mg/L for Cu(II) and 0.03 to 1.62 mg/L for Zn(II), which were both higher than those normally recorded in natural waters. The Cu(II) levels also exceeded WHO guidelines for drinking water in 27% of the samples. The highest prevalence of excessive Cu(II) was found among dams and open pans (38%), piped water (33%) and spring water (25%). It was estimated that 18.2% of the resident communities in the current study area are exposed to potentially toxic levels of Cu(II) through their drinking water. PMID:26615531

  3. Directed synthesis of a heterobimetallic complex based on a novel unsymmetric double-Schiff-base ligand: preparation, characterization, reactivity and structures of hetero- and homobimetallic nickel(II) and zinc(II) complexes.

    PubMed

    Roth, Arne; Buchholz, Axel; Rudolph, Manfred; Schütze, Eileen; Kothe, Erika; Plass, Winfried

    2008-01-01

    A series of bimetallic zinc(II) and nickel(II) complexes based on the novel dinucleating unsymmetric double-Schiff-base ligand benzoic acid [1-(3-{[2-(bispyridin-2-ylmethylamino)ethylimino]methyl}-2-hydroxy-5-methylphenyl)methylidene]hydrazide (H(2)bpampbh) has been synthesized and structurally characterized. The metal centers reside in two entirely different binding pockets provided by the ligand H(2)bpampbh, a planar tridentate [ONO] and a pentadentate [ON(4)] compartment. The utilized ligand H(2)bpampbh has been synthesized by condensation of the single-Schiff-base proligand Hbpahmb with benzoic acid hydrazide. The reaction of H(2)bpampbh with two equivalents of either zinc(II) or nickel(II) acetate yields the homobimetallic complexes [Zn(2)(bpampbh)(mu,eta(1)-OAc)(eta(1)-OAc)] (ZnZn) and [Ni(2)(bpampbh)(mu-H(2)O)(eta(1)-OAc)(H(2)O)](OAc) (NiNi), respectively. Simultaneous presence of one equivalent zinc(II) and one equivalent nickel(II) acetate results in the directed formation of the heterobimetallic complex [NiZn(bpampbh)(mu,eta(1)-OAc)(eta(1)-OAc)] (NiZn) with a selective binding of the nickel ions in the pentadentate ligand compartment. In addition, two homobimetallic azide-bridged complexes [Ni(2)(bpampbh)(mu,eta(1)-N(3))]ClO(4) (NiNi(N(3))) and [Ni(2)(bpampbh)(mu,eta(1)-N(3))(MeOH)(2)](ClO(4))(0.5)(N(3))(0.5) (NiNi(N(3))(MeOH)(2)) were synthesized. In all complexes, the metal ions residing in the pentadentate compartment adopt a distorted octahedral coordination geometry, whereas the metal centers placed in the tridentate compartment vary in coordination number and geometry from square-planar (NiNi(N(3))) and square-pyramidal (ZnZn and NiZn), to octahedral (NiNi and NiNi(N(3))(MeOH)(2)). In the case of complex NiNi(N(3)) this leads to a mixed-spin homodinuclear nickel(II) complex. All compounds have been characterized by means of mass spectrometry as well as IR and UV/Vis spectroscopies. Magnetic susceptibility measurements show significant zero

  4. Pharmacological Role of Anions (Sulphate, Nitrate, Oxalate and Acetate) on the Antibacterial Activity of Cobalt(II), Copper(II) and Nickel(II) Complexes With Nicotinoylhydrazine-Derived ONO, NNO and SNO Ligands.

    PubMed

    Chohan, Z H; Rauf, A

    1996-01-01

    Mixed ligands biologically active complexes of cobalt(II), copper(II) and nickel(II) with nicotinoylhydrazine-derived ONO, NNO and SNO donor schiff-base ligands having the same metal ion but different anions such as sulphate, nitrate, oxalate and acetate have been synthesised and characterised on the basis of their physical, analytical and spectral data. In order to evaluate the role of anions on their bioability, these ligands and their synthesised metal complexes with various anions have been screened against bacterial species such as Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus and the title studies have proved a definative role of anions in increasing the biological activity. PMID:18472896

  5. Pharmacological Role of Anions (Sulphate, Nitrate, Oxalate and Acetate) on the Antibacterial Activity of Cobalt(II), Copper(II) and Nickel(II) Complexes With Nicotinoylhydrazine-Derived ONO, NNO and SNO Ligands

    PubMed Central

    Rauf, Abdur

    1996-01-01

    Mixed ligands biologically active complexes of cobalt(II), copper(II) and nickel(II) with nicotinoylhydrazine-derived ONO, NNO and SNO donor schiff-base ligands having the same metal ion but different anions such as sulphate, nitrate, oxalate and acetate have been synthesised and characterised on the basis of their physical, analytical and spectral data. In order to evaluate the role of anions on their bioability, these ligands and their synthesised metal complexes with various anions have been screened against bacterial species such as Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus and the title studies have proved a definative role of anions in increasing the biological activity PMID:18472896

  6. Halo-substituted thiosemicarbazones and their copper(II), nickel(II) complexes: Detailed spectroscopic characterization and study of antitumour activity against HepG2 human hepatoblastoma cells

    NASA Astrophysics Data System (ADS)

    Jagadeesh, M.; Kalangi, Suresh K.; Sivarama Krishna, L.; Reddy, A. Varada

    2014-01-01

    Copper(II) and nickel(II) complexes of two different halogen substituted thiosemicarbazone ligands were synthesized. The ligands 3,4-difluoroacetophenone thiosemicarbazone (1) and 2-bromo-4'-chloroacetophenone thiosemicarbazone (2) were characterized and confirmed spectroscopically by FT-IR, FT-Raman, UV-vis and fluorescence spectral analysis, while the respective copper(II) complexes [Cu(C9H9N3F2S)2Cl2] (1a), [Cu(C9H9N3ClBrS)2Cl2] (2a) and nickel(II) complexes [Ni(C9H9N3F2S)2] (1b), [Ni(C9H9N3ClBrS)2] (2b) were characterized by FT-IR, UV-vis and electron paramagnetic spectroscopy (EPR). The EPR spectra of the Cu(II) complexes provided the rhombic octahedral and axial symmetry of the complexes 1a and 2a respectively. For the complex 1a, the g values calculated as g1 = 2.1228, g2 = 2.0706 and g3 = 2.001 between 2900 and 3300 G. While for the complex 2a, a set of two resonance absorptions were observed. The synthesized compounds were tested for antitumor activity and showed that the ability to kill liver cancer cells significantly. Out of all the synthesized compounds, copper(II) complexes 1a and 2a showed high cytotoxic effect on liver cancer cells with 67.51% and 42.77% of cytotoxicity respectively at 100 μM.

  7. Halo-substituted thiosemicarbazones and their copper(II), nickel(II) complexes: detailed spectroscopic characterization and study of antitumour activity against HepG2 human hepatoblastoma cells.

    PubMed

    Jagadeesh, M; Kalangi, Suresh K; Sivarama Krishna, L; Reddy, A Varada

    2014-01-24

    Copper(II) and nickel(II) complexes of two different halogen substituted thiosemicarbazone ligands were synthesized. The ligands 3,4-difluoroacetophenone thiosemicarbazone (1) and 2-bromo-4'-chloroacetophenone thiosemicarbazone (2) were characterized and confirmed spectroscopically by FT-IR, FT-Raman, UV-vis and fluorescence spectral analysis, while the respective copper(II) complexes [Cu(C9H9N3F2S)2Cl2] (1a), [Cu(C9H9N3ClBrS)2Cl2] (2a) and nickel(II) complexes [Ni(C9H9N3F2S)2] (1b), [Ni(C9H9N3ClBrS)2] (2b) were characterized by FT-IR, UV-vis and electron paramagnetic spectroscopy (EPR). The EPR spectra of the Cu(II) complexes provided the rhombic octahedral and axial symmetry of the complexes 1a and 2a respectively. For the complex 1a, the g values calculated as g1=2.1228, g2=2.0706 and g3=2.001 between 2900 and 3300 G. While for the complex 2a, a set of two resonance absorptions were observed. The synthesized compounds were tested for antitumor activity and showed that the ability to kill liver cancer cells significantly. Out of all the synthesized compounds, copper(II) complexes 1a and 2a showed high cytotoxic effect on liver cancer cells with 67.51% and 42.77% of cytotoxicity respectively at 100 μM. PMID:24084484

  8. Co-precipitation of Ni, Cr, Mn, Pb and Zn in industrial wastewater and sediment samples with copper(II) cyclo-hexylmethyldithiocarbamate for their flame atomic absorption spectrometric determination.

    PubMed

    Ipeaiyeda, Ayodele Rotimi; Odola, Adekunle Johnson

    2012-01-01

    A co-precipitation technique for nickel(II), chromium(II), manganese(II), lead(II) and zinc(II) with the aid of copper(II) cyclo-hexylmethyldithiocarbamate was established. The influences of some analytical parameters such as pH, sample volume, amounts of cyclo-hexylmethyldithiocarbamate and copper(II) on the recovery of metal ions were investigated. The heavy metals in the precipitate were determined by flame atomic absorption spectrophotometry. The range of detection limits for the heavy metals was 0.003-0.005 mg/L. The atomic spectrometric technique with co-precipitation procedure was successfully applied for the determination of Ni, Cr, Mn, Pb and Zn in industrial wastewater and sediment samples from Ladipo stream in Lagos, Nigeria. The mean concentrations for these metals using co-precipitation procedure were not significantly different from corresponding concentrations obtained using spectrometric techniques without co-precipitation procedure. PMID:22678206

  9. Antifungal cobalt(II), copper(II), nickel(II) and zinc(II) complexes of furanyl-,thiophenyl-, pyrrolyl-, salicylyl- and pyridyl-derived cephalexins.

    PubMed

    Chohan, Zahid H; Pervez, Humayun; Khan, Khalid M; Rauf, A; Maharvi, Ghulam M; Supuran, Claudiu T

    2004-02-01

    Some novel cephalexin-derived furanyl, thiophenyl, pyrrolyl, salicylyl and pyridyl Schiff's bases and their cobalt (II), copper (II), nickel (II) and zinc (II) complexes have been synthesized and studied for their antifungal properties against Trichophyton longifusus, Candida albicans, Aspergillus flavus, Microsporum canis, Fusarium solani and Candida glaberata. The presence of metal ions in the investigated Schiff's base complexes reported here lead to significant antifungal activity, whereas the parent ligands were generally less active. PMID:15202498

  10. Synthesis, structure and antifungal activity of thiophene-2,3-dicarboxaldehyde bis(thiosemicarbazone) and nickel(II), copper(II) and cadmium(II) complexes: unsymmetrical coordination mode of nickel complex.

    PubMed

    Alomar, Kusaï; Landreau, Anne; Allain, Magali; Bouet, Gilles; Larcher, Gérald

    2013-09-01

    The reaction of nickel(II), copper(II) chlorides and cadmium(II) chloride and bromide with thiophene-2,3-dicarboxaldehyde bis(thiosemicarbazone) (2,3BTSTCH2) leads to a series of new complexes: [Ni(2,3BTSTCH)]Cl, [Cu(2,3BTSTC)], [CdCl2(2,3BTSTCH2)] and [CdBr2(2,3BTSTCH2)]. The crystal structures of the ligand and of [Ni(2,3BTSTCH)]Cl complex have been determined. In this case, we remark an unusual non-symmetrical coordination mode for the two functional groups: one acting as a thione and the second as a deprotonated thiolate. All compounds have been tested for their antifungal activity against human pathogenic fungi: Candida albicans, Candida glabrata and Aspergillus fumigatus, the cadmium complexes exhibit the highest antifungal activity. Cytotoxicity was evaluated using two biological methods: human MRC5 cultured cells and brine shrimp Artemia salina bioassay. PMID:23792913

  11. Copper(II) and nickel(II) complexes of tetradentate Schiff base ligand: UV-Vis and FT-IR spectra and DFT calculation of electronic, vibrational and nonlinear optical properties

    NASA Astrophysics Data System (ADS)

    Zarei, Seyed Amir; Khaledian, Donya; Akhtari, Keivan; Hassanzadeh, Keyumars

    2015-11-01

    The experimental fourier transform infrared (FT-IR) and ultraviolet-visible (UV-Vis) spectra of copper(II) and nickel(II) complexes of the deprotonated tetradentate Schiff base ligand N,N‧-bis(2-hydroxybenzylidene)-2,2-dimethyl-1,3-propanediamine (H2L) are compared with their corresponding theoretical ones. The applied theoretical method is based on the density functional theory and time-dependent density functional theory at the UPBE0/PBE0 levels using Def2-TZVP basis set. The computational optimised geometric parameters of the complexes are in good agreement with their corresponding experimental data. The FT-IR and UV-Vis spectra of the complexes were reproduced on the basis of their optimised structures. The vibrational assignments of some fundamental modes of the complexes are performed. The highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) energies are calculated. The analyses of the calculated electronic absorption spectra of the complexes are carried out to elucidate the electronic transitions assignments and their characters. Second-order nonlinear optical property of the complexes is evaluated by the above-mentioned theoretical method that implies much greater values for the complexes in comparison with the corresponding value of urea.

  12. Coordination mode of pentadentate ligand derivative of 5-amino-1,3,4-thiadiazole-2-thiol with nickel(II) and copper(II) metal ions: Synthesis, spectroscopic characterization, molecular modeling and fungicidal study

    NASA Astrophysics Data System (ADS)

    Chandra, Sulekh; Gautam, Seema; Kumar, Amit; Madan, Molly

    2015-02-01

    Complexes of nickel(II), and copper(II) were synthesized with pantadentate ligand i.e. 3,3‧-thiodipropionicacid-bis(5-amino-1,3,4-thiadiazole-2-thiol) (L). The ligand was synthesized by the condensation of thiodipropionic acid and 5-amino-1,3,4-thiadiazole-2-thiol in 1:2 ratio, respectively. Synthesized ligand was characterized by elemental analysis, mass, 1H NMR, IR, and molecular modeling. All the complexes were characterized by elemental analysis, molar conductance, magnetic moment, IR, electronic spectra, ESR, and molecular modeling. The newly synthesized complexes possessed general composition [M(L)X2] where M = Ni(II), Cu(II), L = pantadentate ligand and X = Cl-, CH3COO-. The IR spectral data indicated that the ligand behaved as a pantadentate ligand and coordinated to the metal ion through N2S3 donor atoms. The molar conductance value of Ni(II), and Cu(II) complexes in DMSO corresponded to their electrolytic behavior. On the basis of spectral study, octahedral and tetragonal geometry was assigned for Ni(II) and Cu(II) complexes, respectively. In vitro fungicidal study of ligand and its complexes was investigated against fungi Candida albicans, Candida parapsilosis, Candidia krusei, and Candida tropicalis by means of well diffusion method.

  13. Binuclear cobalt(II), nickel(II), copper(II) and palladium(II) complexes of a new Schiff-base as ligand: Synthesis, structural characterization, and antibacterial activity

    NASA Astrophysics Data System (ADS)

    Geeta, B.; Shravankumar, K.; Reddy, P. Muralidhar; Ravikrishna, E.; Sarangapani, M.; Reddy, K. Krishna; Ravinder, V.

    2010-11-01

    A binucleating new Schiff-base ligand with a phenylene spacer, afforded by the condensation of glycyl-glycine and o-phthalaldehyde has been served as an octadentate N 4O 4 ligand in designing some binuclear complexes of cobalt(II), nickel(II), copper(II), and palladium(II). The binding manner of the ligand to the metal and the composition and geometry of the metal complexes were examined by elemental analysis, conductivity measurements, magnetic moments, IR, 1H, 13C NMR, ESR and electronic spectroscopies, and TGA measurements. There are two different coordination/chelation environments present around two metal centers of each binuclear complex. The composition of the complexes in the coordination sphere was found to be [M 2(L)(H 2O) 4] (where M = Co(II) and Ni(II)) and [M 2(L)] (where M = Cu(II) and Pd(II)). In the case of Cu(II) complexes, ESR spectra provided further information to confirm the binuclear structure and the presence of magnetic interactions. All the above metal complexes have shown moderate to good antibacterial activity against Gram-positive and Gram-negative bacteria.

  14. Crystal structures of a copper(II) and the isotypic nickel(II) and palladium(II) complexes of the ligand (E)-1-[(2,4,6-tri-bromo-phen-yl)diazen-yl]naphthalen-2-ol.

    PubMed

    Chetioui, Souheyla; Rouag, Djamil-Azzeddine; Djukic, Jean-Pierre; Bochet, Christian G; Touzani, Rachid; Bailly, Corinne; Crochet, Aurélien; Fromm, Katharina M

    2016-08-01

    In the copper(II) complex, bis-{(E)-1-[(2,4,6-tri-bromo-phen-yl)diazen-yl]naph-thalen-2-olato}copper(II), [Cu(C16H8Br3N2O)2], (I), the metal cation is coord-inated by two N atoms and two O atoms from two bidentate (E)-1-[(2,4,6-tri-bromo-phen-yl)diazen-yl]naphthalen-2-olate ligands, forming a slightly distorted square-planar environment. In one of the ligands, the tri-bromo-benzene ring is inclined to the naphthalene ring system by 37.4 (5)°, creating a weak intra-molecular Cu⋯Br inter-action [3.134 (2) Å], while in the other ligand, the tri-bromo-benzene ring is inclined to the naphthalene ring system by 72.1 (6)°. In the isotypic nickel(II) and palladium(II) complexes, namely bis-{(E)-1-[(2,4,6-tri-bromo-phen-yl)diazen-yl]naphthalen-2-olato}nickel(II), [Ni(C16H8Br3N2O)2], (II), and bis-{(E)-1-[(2,4,6-tri-bromo-phen-yl)diazen-yl]naphthalen-2-olato}palladium(II), [Pd(C16H8Br3N2O)2], (III), respectively, the metal atoms are located on centres of inversion, hence the metal coordination spheres have perfect square-planar geometries. The tri-bromo-benzene rings are inclined to the naphthalene ring systems by 80.79 (18)° in (II) and by 80.8 (3)° in (III). In the crystal of (I), mol-ecules are linked by C-H⋯Br hydrogen bonds, forming chains along [010]. The chains are linked by C-H⋯π inter-actions, forming sheets parallel to (011). In the crystals of (II) and (III), mol-ecules are linked by C-H⋯π inter-actions, forming slabs parallel to (10-1). For the copper(II) complex (I), a region of disordered electron density was corrected for using the SQUEEZE routine in PLATON [Spek (2015 ▸). Acta Cryst. C71, 9-18]. The formula mass and unit-cell characteristics of the disordered solvent mol-ecules were not taken into account during refinement. PMID:27536389

  15. Structure-antiproliferative activity studies on l-proline- and homoproline-4-N-pyrrolidine-3-thiosemicarbazone hybrids and their nickel(ii), palladium(ii) and copper(ii) complexes.

    PubMed

    Dobrova, Aliona; Platzer, Sonja; Bacher, Felix; Milunovic, Miljan N M; Dobrov, Anatolie; Spengler, Gabriella; Enyedy, Éva A; Novitchi, Ghenadie; Arion, Vladimir B

    2016-09-14

    Two water-soluble thiosemicarbazone-proline (H2L(1)) and thiosemicarbazone-homoproline hybrids (H2L(2)) were synthesised. By reaction of H2L(1) with NiCl2·6H2O, PdCl2 and CuCl2·2H2O in ethanol, the series of square-planar complexes [Ni(H2L(1))Cl]Cl·1.3H2O (1·1.3H2O), [Pd(H2L(1))Cl]Cl·H2O (2·H2O) and [Cu(H2L(1))Cl]Cl·0.7H2O (3·0.7H2O) was prepared, and starting from H2L(2) and CuCl2·2H2O in methanol, the complex [Cu(H2L(2))Cl2]·H2O (4·H2O) was obtained. The compounds have been characterised by elemental analysis, spectroscopic methods (IR, UV-vis and NMR spectroscopy), ESI mass spectrometry and single crystal X-ray crystallography (H2L(1), 1, 2 and 4). As a solid, 1 is diamagnetic, while it is paramagnetic in methanolic solution. The effective magnetic moment of 3.26 B.M. at room temperature indicates the change in coordination geometry from square-planar to octahedral upon dissolution. The in vitro anticancer potency of ligand precursors H2L(1) and H2L(2) and metal complexes 1-4 was studied in three human cancer cell lines (A549, CH1 and SW480) and in noncancerous murine embryonal fibroblasts (NIH/3T3), and the mechanism of cell death was also assayed by flow cytometry. Clear-cut structure-activity relationships have been established. The metal ions exert marked effects in a divergent manner: copper(ii) increases, whereas nickel(ii) and palladium(ii) decrease the cytotoxicity of the hybrids. The antiproliferative activity of H2L(1) and metal complexes 1-3 decreases in all three tumour cell lines in the following rank order: 3 > H2L(1) > 1 > 2. The role of square-planar geometry in the underlying mechanism of cytotoxicity of the metal complexes studied seems to be negligible, while structural modifications at the terminal amino group of thiosemicarbazide and proline moieties are significant for enhancing the antiproliferative activity of both hybrids and copper(ii) complexes. PMID:27485263

  16. Di- and tetra-nuclear copper(II), nickel(II), and cobalt(II) complexes of four bis-tetradentate triazole-based ligands: synthesis, structure, and magnetic properties.

    PubMed

    Olguín, Juan; Kalisz, Marguerite; Clérac, Rodolphe; Brooker, Sally

    2012-05-01

    Four bis-tetradentate N(4)-substituted-3,5-{bis[bis-N-(2-pyridinemethyl)]aminomethyl}-4H-1,2,4-triazole ligands, L(Tz1)-L(Tz4), differing only in the triazole N(4) substituent R (where R is amino, pyrrolyl, phenyl, or 4-tertbutylphenyl, respectively) have been synthesized, characterized, and reacted with M(II)(BF(4))(2)·6H(2)O (M(II) = Cu, Ni or Co) and Co(SCN)(2). Experiments using all 16 possible combinations of metal salt and L(TzR) were carried out: 14 pure complexes were obtained, 11 of which are dinuclear, while the other three are tetranuclear. The dinuclear complexes include two copper(II) complexes, [Cu(II)(2)(L(Tz2))(H(2)O)(4)](BF(4))(4) (2), [Cu(II)(2)(L(Tz4))(BF(4))(2)](BF(4))(2) (4); two nickel(II) complexes, [Ni(II)(2)(L(Tz1))(H(2)O)(3)(CH(3)CN)](BF(4))(4)·0.5(CH(3)CN) (5) and [Ni(II)(2)(L(Tz4))(H(2)O)(4)](BF(4))(4)·H(2)O (8); and seven cobalt(II) complexes, [Co(II)(2)(L(Tz1))(μ-BF(4))](BF(4))(3)·H(2)O (9), [Co(II)(2)(L(Tz2))(μ-BF(4))](BF(4))(3)·2H(2)O (10), [Co(II)(2)(L(Tz3))(H(2)O)(2)](BF(4))(4) (11), [Co(II)(2)(L(Tz4))(μ-BF(4))](BF(4))(3)·3H(2)O (12), [Co(II)(2)(L(Tz1))(SCN)(4)]·3H(2)O (13), [Co(II)(2)(L(Tz2))(SCN)(4)]·2H(2)O (14), and [Co(II)(2)(L(Tz3))(SCN)(4)]·H(2)O (15). The tetranuclear complexes are [Cu(II)(4)(L(Tz1))(2)(H(2)O)(2)(BF(4))(2)](BF(4))(6) (1), [Cu(II)(4)(L(Tz3))(2)(H(2)O)(2)(μ-F)(2)](BF(4))(6)·0.5H(2)O (3), and [Ni(II)(4)(L(Tz3))(2)(H(2)O)(4)(μ-F(2))](BF(4))(6)·6.5H(2)O (7). Single crystal X-ray structure determinations revealed different solvent content from that found by microanalysis of the bulk sample after drying under a vacuum and confirmed that 5', 8', 9', 11', 12', and 15' are dinuclear while 1' and 7' are tetranuclear. As expected, magnetic measurements showed that weak antiferromagnetic intracomplex interactions are present in 1, 2, 4, 7, and 8, stabilizing a singlet spin ground state. All seven of the dinuclear cobalt(II) complexes, 9-15, have similar magnetic behavior and remain in the [HS-HS] state

  17. Syntheses, electronic structures, and EPR/UV-vis-NIR spectroelectrochemistry of nickel(II), copper(II), and zinc(II) complexes with a tetradentate ligand based on S-methylisothiosemicarbazide.

    PubMed

    Arion, Vladimir B; Rapta, Peter; Telser, Joshua; Shova, Sergiu S; Breza, Martin; Luspai, Karol; Kozisek, Jozef

    2011-04-01

    Template condensation of 3,5-di-tert-butyl-2-hydroxybenzaldehyde S-methylisothiosemicarbazone with pentane-2,4-dione and triethyl orthoformate at elevated temperatures resulted in metal complexes of the type M(II)L, where M = Ni and Cu and H(2)L = a novel tetradentate ligand. These complexes are relevant to the active site of the copper enzymes galactose oxidase and glyoxal oxidase. Demetalation of Ni(II)L with gaseous hydrogen chloride in chloroform afforded the metal-free ligand H(2)L. Then by the reaction of H(2)L with Zn(CH(3)COO)(2)·2H(2)O in a 1:1 molar ratio in 1:2 chloroform/methanol, the complex Zn(II)L(CH(3)OH) was prepared. The three metal complexes and the prepared ligand were characterized by spectroscopic methods (IR, UV-vis, and NMR spectroscopy), X-ray crystallography, and DFT calculations. Electrochemically generated one-electron oxidized metal complexes [NiL](+), [CuL](+), and [ZnL(CH(3)OH)](+) and the metal-free ligand cation radical [H(2)L](+•) were studied by EPR/UV-vis-NIR and DFT calculations. These studies demonstrated the interaction between the metal ion and the phenoxyl radical. PMID:21361344

  18. Synthesis, characterization, X-ray crystal structures and antibacterial activities of Schiff base ligands derived from allylamine and their vanadium(IV), cobalt(III), nickel(II), copper(II), zinc(II) and palladium(II) complexes

    NASA Astrophysics Data System (ADS)

    Amiri Rudbari, Hadi; Iravani, Mohammad Reza; Moazam, Vahid; Askari, Banafshe; Khorshidifard, Mahsa; Habibi, Neda; Bruno, Giuseppe

    2016-12-01

    A new Schiff base ligand, HL2, and four new Schiff base complexes, NiL12, PdL12, NiL22 and ZnL22, have been prepared and characterized by elemental analysis (CHN), FT-IR and UV-Vis spectroscopy. 1H and 13C NMR techniques were employed for characterization of the ligand (HL2) and the diamagnetic complexes (PdL12 and ZnL22). The molecular structures of PdL12, NiL22 and ZnL22 complexes were determined by the single crystal X-ray diffraction technique. The crystallographic data reveal that in these complexes the metal centers are four-coordinated by two phenolate oxygen and two imine nitrogen atoms of two Schiff base ligands. The geometry around the metal center in the PdL12 and NiL22 complexes is square-planar and for ZnL22 it is a distorted tetrahedral.In the end, five new (HL2, NiL12, PdL12, NiL22 and ZnL22) and six reported (HL1, VOL12, CoL13, CuL12, ZnL12 and Zn2L14) Schiff base compounds were tested for their in vitro antimicrobial activity against Staphylococcus aureus and Escherichia coli as examples of Gram-positive and Gram-negative bacterial strains, respectively, by disc diffusion method.

  19. Crystal structures of a copper(II) and the isotypic nickel(II) and palladium(II) complexes of the ligand (E)-1-[(2,4,6-tri­bromo­phen­yl)diazen­yl]naphthalen-2-ol

    PubMed Central

    Chetioui, Souheyla; Rouag, Djamil-Azzeddine; Djukic, Jean-Pierre; Bochet, Christian G.; Touzani, Rachid; Bailly, Corinne; Crochet, Aurélien; Fromm, Katharina M.

    2016-01-01

    In the copper(II) complex, bis­{(E)-1-[(2,4,6-tri­bromo­phen­yl)diazen­yl]naph­thalen-2-olato}copper(II), [Cu(C16H8Br3N2O)2], (I), the metal cation is coord­inated by two N atoms and two O atoms from two bidentate (E)-1-[(2,4,6-tri­bromo­phen­yl)diazen­yl]naphthalen-2-olate ligands, forming a slightly distorted square-planar environment. In one of the ligands, the tri­bromo­benzene ring is inclined to the naphthalene ring system by 37.4 (5)°, creating a weak intra­molecular Cu⋯Br inter­action [3.134 (2) Å], while in the other ligand, the tri­bromo­benzene ring is inclined to the naphthalene ring system by 72.1 (6)°. In the isotypic nickel(II) and palladium(II) complexes, namely bis­{(E)-1-[(2,4,6-tri­bromo­phen­yl)diazen­yl]naphthalen-2-olato}nickel(II), [Ni(C16H8Br3N2O)2], (II), and bis­{(E)-1-[(2,4,6-tri­bromo­phen­yl)diazen­yl]naphthalen-2-olato}palladium(II), [Pd(C16H8Br3N2O)2], (III), respectively, the metal atoms are located on centres of inversion, hence the metal coordination spheres have perfect square-planar geometries. The tri­bromo­benzene rings are inclined to the naphthalene ring systems by 80.79 (18)° in (II) and by 80.8 (3)° in (III). In the crystal of (I), mol­ecules are linked by C—H⋯Br hydrogen bonds, forming chains along [010]. The chains are linked by C—H⋯π inter­actions, forming sheets parallel to (011). In the crystals of (II) and (III), mol­ecules are linked by C—H⋯π inter­actions, forming slabs parallel to (10-1). For the copper(II) complex (I), a region of disordered electron density was corrected for using the SQUEEZE routine in PLATON [Spek (2015 ▸). Acta Cryst. C71, 9–18]. The formula mass and unit-cell characteristics of the disordered solvent mol­ecules were not taken into account during refinement. PMID:27536389

  20. Cyclam Derivatives with a Bis(phosphinate) or a Phosphinato-Phosphonate Pendant Arm: Ligands for Fast and Efficient Copper(II) Complexation for Nuclear Medical Applications.

    PubMed

    David, Tomáš; Kubíček, Vojtěch; Gutten, Ondrej; Lubal, Přemysl; Kotek, Jan; Pietzsch, Hans-Jürgen; Rulíšek, Lubomír; Hermann, Petr

    2015-12-21

    Cyclam derivatives bearing one geminal bis(phosphinic acid), -CH2PO2HCH2PO2H2 (H2L(1)), or phosphinic-phosphonic acid, -CH2PO2HCH2PO3H2 (H3L(2)), pendant arm were synthesized and studied as potential copper(II) chelators for nuclear medical applications. The ligands showed good selectivity for copper(II) over zinc(II) and nickel(II) ions (log KCuL = 25.8 and 27.7 for H2L(1) and H3L(2), respectively). Kinetic study revealed an unusual three-step complex formation mechanism. The initial equilibrium step leads to out-of-cage complexes with Cu(2+) bound by the phosphorus-containing pendant arm. These species quickly rearrange to an in-cage complex with cyclam conformation II, which isomerizes to another in-cage complex with cyclam conformation I. The first in-cage complex is quantitatively formed in seconds (pH ≈5, 25 °C, Cu:L = 1:1, cM ≈ 1 mM). At pH >12, I isomers undergo nitrogen atom inversion, leading to III isomers; the structure of the III-[Cu(HL(2))] complex in the solid state was confirmed by X-ray diffraction analysis. In an alkaline solution, interconversion of the I and III isomers is mutual, leading to the same equilibrium isomeric mixture; such behavior has been observed here for the first time for copper(II) complexes of cyclam derivatives. Quantum-chemical calculations showed small energetic differences between the isomeric complexes of H3L(2) compared with analogous data for isomeric complexes of cyclam derivatives with one or two methylphosphonic acid pendant arm(s). Acid-assisted dissociation proved the kinetic inertness of the complexes. Preliminary radiolabeling of H2L(1) and H3L(2) with (64)Cu was fast and efficient, even at room temperature, giving specific activities of around 70 GBq of (64)Cu per 1 μmol of the ligand (pH 6.2, 10 min, ca. 90 equiv of the ligand). These specific activities were much higher than those of H3nota and H4dota complexes prepared under identical conditions. The rare combination of simple ligand synthesis, very

  1. A spectral study of 2-formylimidazole 4N-substituted thiosemicarbazones and their copper(II) complexes

    NASA Astrophysics Data System (ADS)

    West, Douglas X.; Lockwood, Mark A.; Albert, Julyan N.; Liberta, Anthony E.

    1993-11-01

    Copper(II) complexes of 2-formylimidazole 4N-methyl-, 4N-dimethyl- 4N-ethyl- and 3-hexa-methyleneiminylthiosemicarbazone, along with two nickel(II) complexes of the latter thiosemicarbazone, have been synthesized. Infrared, electronic, NMR and ESR spectra have been used to characterize the complexes and the uncomplexed thiosemicarbazones. None of the complexes or thiosemicarbazones possess growth inhibitory activity against Aspergillus niger and Paecilomyces variotii.

  2. Synthesis, structural characterization and antimicrobial activities of 12 zinc(II) complexes with four thiosemicarbazone and two semicarbazone ligands.

    PubMed

    Kasuga, Noriko Chikaraishi; Sekino, Kiyoshi; Ishikawa, Motoki; Honda, Ayano; Yokoyama, Masaki; Nakano, Saori; Shimada, Nobuhiro; Koumo, Chisa; Nomiya, Kenji

    2003-08-01

    ,6-diacetylpyridine bis(4N-morpholyl thiosemicarbazone) and H(2)datsc=2,6-diacetylpyridine bis(thiosemicarbazone)]), did not inhibit the growth of the test organisms. On the contrary, 7-coordinate zinc(II) complexes with one pentadentate semicarbazone ligand and two water molecules, ([Zn(H(2)dasc)(H(2)O)(2)](OAc)(2).5.3H(2)O 11 and [Zn(H(2)dasc)(H(2)O)(2)](NO(3))(2).H(2)O 12 [H(2)dasc=2,6-diacetylpyridine bis(semicarbazone)]), showed modest to moderate activities against bacteria. Based on the X-ray structures, the structure-activity correlation for the antimicrobial activities was elucidated. The zinc(II) complexes with 4N-substituted ligands showed no antimicrobial activities. In contrast to the previously reported nickel(II) complexes, properties of the ligands such as the ability to form hydrogen bonding with a counter anion or hydrated water molecules or the less bulkiness of the 4N moiety would be a more important factor for antimicrobial activities than the coordination number of the metal ion for the zinc(II) complexes. PMID:12888265

  3. Cadmium(II) and zinc(II) complexes of pyrrole-appended oxacarbaporphyrin: a side-on coordination mode of O-confused carbaporphyrin.

    PubMed

    Pawlicki, Miłosz; Latos-Grazyński, Lechosław; Szterenberg, Ludmiła

    2005-12-26

    A pyrrole adduct of 5,20-diphenyl-10,15-di(p-tolyl)-2-oxa-21-carbaporphyrin [(H,pyr)OCPH]H(2) reacted with sodium ethanolate to yield 5,20-diphenyl-10,15-di(p-tolyl)-3-ethoxy-3-(2'-pyrrol)-2-oxa-21-carbaporphyrin [(EtO,pyr)OCPH]H(2). Subsequently, "true" O-confused oxaporphyrin with a pendant pyrrole ring [(pyr)OCPH]H was formed by the addition of acid to [(EtO,pyr)OCPH]H(2), which triggered an ethanol elimination. In the course of this process, the tetrahedral-trigonal rearrangements originated at the C(3) atom. Insertion of zinc(II), cadmium(II), and nickel(II) into [(pyr)OCPH]H yielded [(pyr)OCPH]Zn(II)Cl, [(pyr)OCPH]Cd(II)Cl, and [(pyr)OCP]Ni(II). The formation of [(pyr)OCP]Ni(II) was accompanied by the C(21)H dehydrogenation step. The nickel(II) ion of [(pyr)OCP]Ni(II), coordinated to a dianionic macrocyclic ligand, is bound by three pyrrolic nitrogens and a trigonally hybridized C(21) atom of the inverted furan. The pyrrole-appended O-confused carbaporphyrin acts as a monoanionic ligand toward zinc(II) and cadmium(II) cations. Three nitrogen atoms and the C(21)H fragment of the inverted furan occupy equatorial positions. In (1)H NMR spectra, the unique inner C(21)H resonances of the inverted furan ring are located at 0.15 ppm for [(pyr)OCPH]Zn(II)Cl, and at 0.21 ppm for [(pyr)OCPH]Cd(II)Cl. The proximity of the furan fragment to the metal ion induces direct scalar couplings between the spin-active nucleus of the metal ((111/113)Cd) and the adjacent (1)H nucleus. The interaction of the metal ion and C(21)H was also reflected by significant changes in carbon chemical shifts ([(pyr)OCPH]Zn(II)Cl, 78.3 ppm; [(pyr)OCPH]Cd(II)Cl, 81.4 ppm; the free base, 101.3 ppm). The density functional theory (DFT) has been applied to model the molecular structures of zinc(II) and cadmium(II) complexes of O-confused oxaporphyrin with an appended pyrrole ring. The Cd...C(21) distance in the optimized structure exceeds the typical Cd-C bond lengths, but is much shorter than the

  4. STUDIES ON BIOSORPTION OF ZINC(II) AND COPPER(II) ON DESULFOVIBRIO DESULFURICANS

    EPA Science Inventory

    The objectives of thes studies are to determine the equilibrium concentration and kinetics of metal sorption on sulfate-reducing bacteria (SRB) isolates. Adsorption establishes the net reversible cellular metal uptake and is related to SRB metal toxicity and the effects of enviro...

  5. Nickel(II) and copper(II) complexes with humic acid anions and their derivatives

    SciTech Connect

    Ryabova, I.N.

    2008-01-15

    Complexation of Ni(II) and Cu(II) in aqueous solutions with anions of humic acids, extracted from naturally oxidized coal, and with their hydroxymethyl derivatives is studied spectrophotometrically and potentiometrically. The complexation stoichiometry and the stability constants of the complexes are determined.

  6. Structural studies of six and four coordinate zinc(II), nickel(II) and dioxovanadium(V) complexes with thiosemicarbazones

    NASA Astrophysics Data System (ADS)

    Sreekanth, A.; Sivakumar, S.; Prathapachandra Kurup, M. R.

    2003-07-01

    Three Zn(II) complexes of di-2-pyridyl ketone thiosemicarbazone, an octahedral Ni(II) complex of 2-acetylpyridine hexamethyleneiminyl-3-thiosemicarbazone, and a V(V) complex of 2-acetylpyridine morpholyl-3-thiosemicarbazone were prepared and characterized. Crystal structure of Ni(II) and V(V) complexes are reported. The ligand in the nickel complex is found to coordinate in the thione form with a pseudo octahedral geometry and the vanadium(V) complex has trigonal bipyramidal geometry.

  7. Electronic structure of nickel(II) and zinc(II) borohydrides from spectroscopic measurements and computational modeling.

    PubMed

    Desrochers, Patrick J; Sutton, Christopher A; Abrams, Micah L; Ye, Shengfa; Neese, Frank; Telser, Joshua; Ozarowski, Andrew; Krzystek, J

    2012-03-01

    The previously reported Ni(II) complex, Tp*Ni(κ(3)-BH(4)) (Tp* = hydrotris(3,5-dimethylpyrazolyl)borate anion), which has an S = 1 spin ground state, was studied by high-frequency and -field electron paramagnetic resonance (HFEPR) spectroscopy as a solid powder at low temperature, by UV-vis-NIR spectroscopy in the solid state and in solution at room temperature, and by paramagnetic (11)B NMR. HFEPR provided its spin Hamiltonian parameters: D = 1.91(1) cm(-1), E = 0.285(8) cm(-1), g = [2.170(4), 2.161(3), 2.133(3)]. Similar, but not identical parameters were obtained for its borodeuteride analogue. The previously unreported complex, Tp*Zn(κ(2)-BH(4)), was prepared, and IR and NMR spectroscopy allowed its comparison with analogous closed shell borohydride complexes. Ligand-field theory was used to model the electronic transitions in the Ni(II) complex successfully, although it was less successful at reproducing the zero-field splitting (zfs) parameters. Advanced computational methods, both density functional theory (DFT) and ab initio wave function based approaches, were applied to these Tp*MBH(4) complexes to better understand the interaction between these metals and borohydride ion. DFT successfully reproduced bonding geometries and vibrational behavior of the complexes, although it was less successful for the spin Hamiltonian parameters of the open shell Ni(II) complex. These were instead best described using ab initio methods. The origin of the zfs in Tp*Ni(κ(3)-BH(4)) is described and shows that the relatively small magnitude of D results from several spin-orbit coupling (SOC) interactions of large magnitude, but with opposite sign. Spin-spin coupling (SSC) is also shown to be significant, a point that is not always appreciated in transition metal complexes. Overall, a picture of bonding and electronic structure in open and closed shell late transition metal borohydrides is provided, which has implications for the use of these complexes in catalysis and hydrogen storage. PMID:22335547

  8. Metal complexes of salicylhydroxamic acid (H2Sha), anthranilic hydroxamic acid and benzohydroxamic acid. Crystal and molecular structure of [Cu(phen)2(Cl)]Cl x H2Sha, a model for a peroxidase-inhibitor complex.

    PubMed

    O'Brien, E C; Farkas, E; Gil, M J; Fitzgerald, D; Castineras, A; Nolan, K B

    2000-04-01

    Stability constants of iron(III), copper(II), nickel(II) and zinc(II) complexes of salicylhydroxamic acid (H2Sha), anthranilic hydroxamic acid (HAha) and benzohydroxamic acid (HBha) have been determined at 25.0 degrees C, I=0.2 mol dm(-3) KCl in aqueous solution. The complex stability order, iron(III) > copper(II) > nickel(II) approximately = zinc(II) was observed whilst complexes of H2Sha were found to be more stable than those of the other two ligands. In the preparation of ternary metal ion complexes of these ligands and 1,10-phenanthroline (phen) the crystalline complex [Cu(phen)2(Cl)]Cl x H2Sha was obtained and its crystal structure determined. This complex is a model for hydroxamate-peroxidase inhibitor interactions. PMID:10830846

  9. New synthetic method of zinc(II) complexes based on mixing.

    PubMed

    Takaya, Masahiro

    2005-10-01

    An environmentally benign new synthetic method of zinc(II) complexes without the use of organic solvents and alkali was developed, and several types of zinc(II) complexes in high yields were prepared by mixing solid ligands with solid Zn(OH)(2) or ZnO. PMID:16205041

  10. Synthesis of New Five Coordinated Copper(II) and Nickel(II) Complexes of L-Valine and Kinetic Study of Copper(II) with Calf Thymus DNA

    PubMed Central

    Tak, Aijaz Ahmad; Arjmand, Farukh

    2002-01-01

    Five coordinated novel complexes of Cu II and Ni II have been synthesized from benzil and 1,3- diaminopropane- Cu II / Ni II complex and characterized by elemental analysis, i.r., n.m.r., e.p.r, molar conductance and u.v-vis, spectroscopy. The complexes are ionic in nature and exhibit pentaeoordinated geometry around the metal ion. The reaction kinetics of C 25 H 36 N 5 O 2 CuCl with calf thymus DNA was studied by u.v-vis, spectroscopy in aqueous medium. The complex after interaction with calf thymus DNA shows shift in the absorption spectrum and hypochromicity indicating an intercalative binding mode. The K obs values have been calculated under pseudo-first order conditions. The redox behaviour of complex C 25 H 36 N 5 O 2 CuCl in the presence and in the absence of calf thymus DNA in the aqueous solution has been investigated by cyclic voltammetry. The cyclic voitammogram exhibits one quasi-reversible redox wave corresponding to Cu II / Cu I redox couple with E 1 / 2 values of -0.377 and -0.237 V respectively at a scan rate of 0.1V s - 1 .On interaction with calf thymus DNA, the complex C 25 H 36 N 5 O 2 CuCl exhibits shifts in both E p as well as in E 1 / 2 values, indicating strong binding of the complex to the calf thymus DNA. PMID:18475428

  11. Anhydrous polymeric zinc(II) penta­noate

    PubMed Central

    Taylor, Richard A.; Ellis, Henry A.

    2008-01-01

    The structure of the title compound, poly[di-μ-penta­noato-zinc(II)], [Zn{CH3(CH2)3COO}2]n, consists of a three-dimensional polymeric layered network with sheets parallel to the (100) plane, in which tetra­hedrally coordinated zinc(II) ions are connected by penta­noate bridges in a syn–anti arrangement. The hydro­carbon chains are in the fully extended all-trans conformation and are arranged in a tail-to-tail double bilayer. PMID:21202761

  12. Use of anodic stripping voltammetry to determine zinc(II), lead(II), and copper(II) in foods

    SciTech Connect

    Maksimkina, L.M.; Gus'kova, V.P.

    1988-01-20

    The existing standard procedure for the polarographic determination of Zn, Pb, and Cu, based on the cathodic polarization of a dropping mercury electrode, is laborious and time-consuming and allows one to determine the above-mentioned trace elements only when they are separated beforehand. We consider the possibility of using anodic stripping voltammetry with a mercury film electrode for the simultaneous determination of Zn(II), Pb(II), and Cu(II) in foods.

  13. Enhancing the Photostability of Arylvinylenebipyridyl Compounds as Fluorescent Indicators for Intracellular Zinc(II) Ions.

    PubMed

    Yuan, Zhao; Younes, Ali H; Allen, John R; Davidson, Michael W; Zhu, Lei

    2015-06-01

    Arylvinylenebipyridyl (AVB) ligands are bright, zinc(II)-sensitive fluoroionophores. The applicability of AVBs as fluorescent indicators for imaging cellular zinc(II), however, is limited by low photostability, partially attributable to the photoisomerization of the vinylene functionality. Two configurationally immobilized (i.e., "locked") AVB analogues are prepared in this work. The zinc(II)-sensitive photophysical properties and zinc(II) affinities of both AVBs and their locked analogues are characterized in organic and aqueous media. The zinc(II) sensitivity of the emission is attributed to the zinc(II)-dependent energies of the charge transfer excited states of these compounds. The configurationally locked ligands have improved photostability, while maintaining the brightness and zinc(II) sensibility of their AVB progenitors. The feasibility of the "locked" AVB analogues with improved photostability for imaging intracellular Zn(II) of eukaryotic cells using laser confocal fluorescence microscopy is demonstrated. PMID:25942357

  14. Enhancing the Photostability of Arylvinylenebipyridyl Compounds as Fluorescent Indicators for Intracellular Zinc(II) Ions

    PubMed Central

    Yuan, Zhao; Younes, Ali H.; Allen, John R.; Davidson, Michael W.; Zhu, Lei

    2015-01-01

    Arylvinylenebipyridyl (AVB) ligands are bright, zinc(II)-sensitive fluoroionophores. The applicability of AVBs as fluorescent indicators for imaging cellular zinc(II), however, is limited by low photostability, partially attributable to the photoisomerization of the vinylene functionality. Two configurationally immobilized (i.e., “locked”) AVB analogues are prepared in this work. The zinc(II)-sensitive photophysical properties and zinc(II) affinities of both AVBs and their locked analogues are characterized in organic and aqueous media. The zinc(II) sensitivity of the emission is attributed to the zinc(II)-dependent energies of the charge transfer excited states of these compounds. The configurationally locked ligands have improved photostability, while maintaining the brightness and zinc(II) sensibility of their AVB progenitors. The feasibility of the “locked” AVB analogues with improved photostability for imaging intracellular Zn(II) of eukaryotic cells using laser confocal fluorescence microscopy is demonstrated. PMID:25942357

  15. Syntheses, characterizations and structures of NO donor Schiff base ligands and nickel(II) and copper(II) complexes

    NASA Astrophysics Data System (ADS)

    Şenol, Cemal; Hayvali, Zeliha; Dal, Hakan; Hökelek, Tuncer

    2011-06-01

    New Schiff base derivatives ( L 1 and L 2) were prepared by the condensation of 2-hydroxy-3-methoxybenzaldehyde ( o-vanillin) and 3-hydroxy-4-methoxybenzaldehyde ( iso-vanillin) with 5-methylfurfurylamine. Two new complexes [Ni(L 1) 2] and [Cu(L 1) 2] have been synthesized with bidentate NO donor Schiff base ligand ( L 1). The Ni(II) and Cu(II) atoms in each complex are four coordinated in a square planar geometry. Schiff bases ( L 1 and L 2) and complexes [Ni(L 1) 2] and [Cu(L 1) 2] were characterized by elemental analyses, FT-IR, UV-vis, mass and 1H, 13C NMR spectroscopies. The crystal structures of the ligand ( L 2) and complexes [Ni(L 1) 2] and [Cu(L 1) 2] have also been determined by using X-ray crystallographic technique.

  16. Copper(II) and nickel(II) complexes of benzyloxybenzaldehyde-4-phenyl-3-thiosemicarbazone: Synthesis, characterization and biological activity

    NASA Astrophysics Data System (ADS)

    Prathima, B.; Subba Rao, Y.; Adinarayana Reddy, S.; Reddy, Y. P.; Varada Reddy, A.

    2010-09-01

    Benzyloxybenzaldehyde-4-phenyl-3-thiosemicarbazone ligand (L) has been synthesized from benzyloxybenzaldehyde and 4-phenyl-3-thiosemicarbazide. Complexes of this ligand with chlorides of Cu(II) and Ni(II) have been prepared. The structure of the ligand (L) is proposed based on elemental analysis, IR and 1H NMR spectra. Its complexes with Cu(II) and Ni(II) ions are characterized from the studies of electronic as well as EPR spectra. On the basis of electronic and EPR studies, rhombically distorted octahedral structure has been proposed for Cu(II) complex while the Ni(II) complex has been found to acquire an octahedral structure. The ligand and their metal complexes have been tested in vitro for their biological effects. Their antibacterial activities against Gram-negative bacteria ( Escherichia coli and Klebsiella pneumoniae) and Gram-positive bacteria ( Staphylococcus aureus and Bacillus subtilis) have been investigated. The prepared metal complexes exhibit higher antibacterial activities than the parent ligand. The in vitro antioxidant activity of free ligand and its metal(II) complexes have also been investigated and the results however reveal that the ligand exhibits greater antioxidant activity than its complexes.

  17. Accessibility control on copper(II) complexes in mesostructured porous silica obtained by direct synthesis using bidentate organosilane ligands.

    PubMed

    Zhou, Wen-Juan; Albela, Belén; Perriat, Pascal; He, Ming-Yuan; Bonneviot, Laurent

    2010-08-17

    The accessibility of metal(II) complexes in 2D hexagonal mesostructured porous silicas obtained by direct synthesis is controlled using an appropriate organosilane ligand. This is exemplified here using copper(II) as a transition metal probe and a neutral or negatively charged ligand: N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, L(A), and, N-salicylaldimine-propylamine-trimethoxysilane, L(B)(-), respectively. L(A) leads to inaccessible complexes located into the pore wall and called "embedded" sites here where silanolate groups from the siliceous network block the access to Cu(II) ions. By contrast, L(B)(-) generates accessible complexes, named "showing-on" sites here. The copper-containing silicas were synthesized with various metal molar ratios (M/SiO(2) = 0.5-3%) in basic media, with cetyltrimethylammonium p-toluenesulfonate (CTATos) as template and with sodium silicate solution as silicon source. A soft template extraction procedure has been developed to preserve the complex integrity of the showing-on copper sites during the treatment. The embedded copper(II) and nickel(II) sites were compared. Materials containing embedded, showing-on, and grafted sites were also compared with regard to pore size, surface polarity, and metal leaching. The material containing showing-on sites was found to be catalytically active for the hydroxylation of phenol into catechol and hydroquinone. Both textural and structural properties of the material and the copper sites were investigated using XRD, TEM, N(2) sorption isotherms, TGA, FT-IR, UV-visible, and EPR spectroscopies. PMID:20695596

  18. Syntheses and spectroscopic studies on zinc(II) and mercury(II) complexes of isatin-3-thiosemicarbazone

    NASA Astrophysics Data System (ADS)

    Akinchan, N. T.; Drożdżewski, P. M.; Holzer, W.

    2002-10-01

    Zinc(II) and mercury(II) complexes were prepared by reacting isatin-3-thiosemicarbazone (ISTSCH) with zinc(II) acetate or mercury(II) bromide. The complexes were characterized by IR, Raman, diffuse reflectance, 1H and 13C NMR spectra and elemental analysis. Tetrahedral structures for Zn(ISTSC) 2 and Hg(ISTSCH)Br 2 are suggested.

  19. Nickel(II) uranium(IV) tris­ulfide

    PubMed Central

    Ward, Matthew D.; Ibers, James A.

    2014-01-01

    Crystals of NiUS3 were obtained from the reaction of the elements Ni, U, S, and of GeI2 in a CsCl flux at 1173 K. Nickel(II) uranium(IV) tris­ulfide, NiUS3, has ortho­rhom­bic (Pnma) symmetry and crystallizes in the GdFeO3 structure type. The compound has a perovskite ABQ 3-like structure, with U occupying the inter­stitial sites of a NiS6 framework. The U atoms are coordinated by eight S atoms in a distorted bicapped trigonal–prismatic arrangement. The Ni atoms are coordinated by six S atoms in a slightly distorted octa­hedral arrangement. The asymmetric unit comprises one U site (site symmetry .m.), one Ni site (-1), and two S sites (1 and .m.). PMID:24526939

  20. Investigation of copper(II) tetrafluoroborate catalysed epoxide opening

    PubMed Central

    Capes, Amy S.; Crossman, Arthur T.; Webster, Lauren A.; Ferguson, Michael A.J.; Gilbert, Ian H.

    2011-01-01

    We report the extension of the copper(II) tetrafluoroborate catalysed opening of epoxides with alcohols to include a wider variety of alcohols, a range of solvents and a method to purify the products from the reaction. PMID:22505782

  1. Structural Variety of Cobalt(II), Nickel(II), Zinc(II), and Cadmium(II) Complexes with 4,4'-Azopyridine: Synthesis, Structure and Luminescence Properties.

    PubMed

    Pladzyk, Agnieszka; Ponikiewski, Łukasz; Dołęga, Anna; Słowy, Klaudia; Sokołowska, Agata; Dziubińska, Katarzyna; Hnatejko, Zbigniew

    2015-11-01

    Self-assembled bi- and polymetallic complexes of Co(II), Ni(II), Zn(II), and Cd(II) were obtained by the reaction of 4,4'-azopyridine (azpy) with metal tri-tert-butoxysilanethiolates (Co, 1; Cd, 2), acetylacetonates (Ni, 3; Zn, 4), and acetates (Cd, 5). All compounds were characterized by single-crystal X-ray structure analysis, elemental analysis, FTIR spectroscopy, and thermogravimetry. Complexes 1, 2 and 4, 5 exhibit diverse structural conformations: 1 is bimetallic, 2 and 4 are 1D coordination polymers, and 5 is a 2D coordination framework formed from bimetallic units. The obtained complexes contain metal atoms bridged by a molecule of azpy. The luminescent properties of 1-5 were investigated in the solid state. PMID:26178314

  2. Optical and thermal properties of nickel(II) hydrazone complex for recordable blu-ray storage

    NASA Astrophysics Data System (ADS)

    Chen, Zhimin; Wu, Yiqun; Gu, Donghong; Gan, Fuxi

    2009-08-01

    A nickel(II) hydrazone complex was synthesized in order to obtain a suitable optical recording medium for the new generation recordable blu-ray disk. Smooth thin films of the nickel(II) hydrazone complex were prepared by using the spin-coating method. Absorption and reflectance spectra of the thin films were evaluated in the wavelength 300-700 nm. Thermal properties of the nickel(II) complex were investigated by thermogravimetry (TG) and differential scanning calorimetry (DSC). Optical constants (complex refractive indices N=n+ik) and thickness of the thin film, prepared on single-crystal silicon substrate, were investigated on a rotating analyzer-polarizer scanning ellipsometer in the wavelength 285-705 nm. In addition, in order to examine its possible use as a blu-ray recording medium, the spin-coated film of the nickel(II) complex was prepared on K9 glass substrate with a silver reflective layer, and was studied by static optical recording testing system with a 406.7 nm laser. It is found that the absorption spectra of the thin film has an strong absorption band in the wavelength region 360-420 nm and a moderate absorbance at the 405 nm side, which indicates that the absorption of the film is well matched with the laser wavelength of the 405 nm. The reflectance spectra show that a high reflectivity of the thin film at 405 nm wavelength can be obtained by an optimum film thickness and an appropriate metal reflective layer. The thin film of the nickel(II) complex gives a high n value of 1.62 and a low k value of 0.33, corresponding to the wavelength of the blue laser of 405 nm. Measurements of the thermal properties show that the nickel(II) complex holds a high thermal stability (~ 300 °C) and a sharp weight loss which are helpful to fabricate a small and sharp recording mark edge. The results of the static optical recording test, using the nickel(II) complex thin film as the recording layer, demonstrate that high reflectivity contrast (>50 %) can be obtained at

  3. Pyrrolidine dithiocarbamate-zinc(II) and -copper(II) complexes induce apoptosis in tumor cells by inhibiting the proteasomal activity

    SciTech Connect

    Milacic, Vesna; Chen Di; Giovagnini, Lorena; Diez, Alejandro; Fregona, Dolores; Dou, Q. Ping

    2008-08-15

    Zinc and copper are trace elements essential for proper folding, stabilization and catalytic activity of many metalloenzymes in living organisms. However, disturbed zinc and copper homeostasis is reported in many types of cancer. We have previously demonstrated that copper complexes induced proteasome inhibition and apoptosis in cultured human cancer cells. In the current study we hypothesized that zinc complexes could also inhibit the proteasomal chymotrypsin-like activity responsible for subsequent apoptosis induction. We first showed that zinc(II) chloride was able to inhibit the chymotrypsin-like activity of a purified 20S proteasome with an IC{sub 50} value of 13.8 {mu}M, which was less potent than copper(II) chloride (IC{sub 50} 5.3 {mu}M). We then compared the potencies of a pyrrolidine dithiocarbamate (PyDT)-zinc(II) complex and a PyDT-copper(II) complex to inhibit cellular proteasomal activity, suppress proliferation and induce apoptosis in various human breast and prostate cancer cell lines. Consistently, zinc complex was less potent than copper complex in inhibiting the proteasome and inducing apoptosis. Additionally, zinc and copper complexes appear to use somewhat different mechanisms to kill tumor cells. Zinc complexes were able to activate calpain-, but not caspase-3-dependent pathway, while copper complexes were able to induce activation of both proteases. Furthermore, the potencies of these PyDT-metal complexes depend on the nature of metals and also on the ratio of PyDT to the metal ion within the complex, which probably affects their stability and availability for interacting with and inhibiting the proteasome in tumor cells.

  4. Pyrrolidine dithiocarbamate-zinc(II) and -copper(II) complexes induce apoptosis in tumor cells by inhibiting the proteasomal activity☆

    PubMed Central

    Milacic, Vesna; Chen, Di; Giovagnini, Lorena; Diez, Alejandro; Fregona, Dolores; Dou, Q. Ping

    2013-01-01

    Zinc and copper are trace elements essential for proper folding, stabilization and catalytic activity of many metalloenzymes in living organisms. However, disturbed zinc and copper homeostasis is reported in many types of cancer. We have previously demonstrated that copper complexes induced proteasome inhibition and apoptosis in cultured human cancer cells. In the current study we hypothesized that zinc complexes could also inhibit the proteasomal chymotrypsin-like activity responsible for subsequent apoptosis induction. We first showed that zinc(II) chloride was able to inhibit the chymotrypsin-like activity of a purified 20S proteasome with an IC50 value of 13.8 μM, which was less potent than copper(II) chloride (IC50 5.3 μM). We then compared the potencies of a pyrrolidine dithiocarbamate (PyDT)-zinc(II) complex and a PyDT-copper(II) complex to inhibit cellular proteasomal activity, suppress proliferation and induce apoptosis in various human breast and prostate cancer cell lines. Consistently, zinc complex was less potent than copper complex in inhibiting the proteasome and inducing apoptosis. Additionally, zinc and copper complexes appear to use somewhat different mechanisms to kill tumor cells. Zinc complexes were able to activate calpain-, but not caspase-3-dependent pathway, while copper complexes were able to induce activation of both proteases. Furthermore, the potencies of these PyDT-metal complexes depend on the nature of metals and also on the ratio of PyDT to the metal ion within the complex, which probably affects their stability and availability for interacting with and inhibiting the proteasome in tumor cells. PMID:18501397

  5. Binding of transition metal ions [cobalt, copper, nickel and zinc] with furanyl-, thiophenyl-, pyrrolyl-, salicylyl- and pyridyl-derived cephalexins as potent antibacterial agents.

    PubMed

    Chohan, Zahid H; Pervez, Humayun; Khan, Khalid Mohammed; Rauf, A; Supuran, Claudiu T

    2004-02-01

    A method is described for the preparation of novel cephalexin-derived furanyl-, thiophenyl-, pyrrolyl-, salicylyl- and pyridyl-containing compounds showing potent antibacterial activity. The binding of these newly synthesized antibacterial agents with metal ions such as cobalt(II), copper(II), nickel(II) and zinc(II) has been studied and their inhibitory properties against various bacterial species such as Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, and Klebsiella pneumoniae are also reported. These results suggest that metal ions to possess an important role in the designing of metal-based antibacterials and that such complexes are more effective against infectious diseases compared to the uncomplexed drugs. PMID:15202493

  6. Synthesis and Characterization of Dimethylbis(2-pyridyl)borate Nickel(II) Complexes: Unimolecular Square-Planar to Square-Planar Rotation around Nickel(II)

    PubMed Central

    2015-01-01

    The syntheses of novel dimethylbis(2-pyridyl)borate nickel(II) complexes 4 and 6 are reported. These complexes were unambiguously characterized by X-ray analysis. In dichloromethane solvent, complex 4 undergoes a unique square-planar to square-planar rotation around the nickel(II) center, for which activation parameters of ΔH⧧ = 12.2(1) kcal mol–1 and ΔS⧧ = 0.8(5) eu were measured via NMR inversion recovery experiments. Complex 4 was also observed to isomerize via a relatively slow ring flip: ΔH⧧ = 15.0(2) kcal mol–1; and ΔS⧧ = −4.2(7) eu. DFT studies support the experimentally measured rotation activation energy (cf. calculated ΔH⧧ = 11.1 kcal mol–1) as well as the presence of a high-energy triplet intermediate (ΔH = 8.8 kcal mol–1). PMID:24882919

  7. Removal of nickel(II) from aqueous solution by Vigna unguiculata (cowpea) pods biomass.

    PubMed

    Guyo, Upenyu; Sibanda, Kudakwashe; Sebata, Edith; Chigondo, Fidelis; Moyo, Mambo

    2016-01-01

    The potential to remove nickel(II) ions from aqueous solution using a biosorbent prepared from Vigna unguiculata pods (VUPs) was investigated in batch experiments. The batch mode experiments were conducted utilising the independent variables of pH (2 to 8), contact time (5 to 120 min), dosage concentration (0.2 to 1.6 g), nickel(II) concentrations (10 to 80 mg L(-1)) and temperature (20 to 50°C). The biosorption data fitted best to the Freundlich biosorption model with a correlation coefficient (R(2)) of 0.993 and lowest chi-squared value of 31.89. The maximum sorption capacity of the VUP for nickel(II) was 27.70 mg g(-1). Kinetics studies revealed that the biosorption process followed the pseudo-second-order model as it had the lowest sum of square error value (0.808) and correlation coefficient close to unity (R(2) = 0.998). The calculated thermodynamic parameters showed that the biosorption process was feasible, spontaneous and endothermic. Consequently, the study demonstrated that VUP biomass could be used as a biosorbent for the removal of nickel(II) from aqueous solution. PMID:27191550

  8. Structural and spectroscopic characterization of two new blue luminescent pyridylbenzimidazole zinc(II) complexes.

    PubMed

    DeStefano, Matthew R; Geiger, David K

    2016-06-01

    Luminescent metal complexes are used in photooptical devices. Zinc(II) complexes are of interest because of the ability to tune their color, their high thermal stability and their favorable carrier transport character. In particular, some zinc(II) complexes with aryl diimine and/or heterocyclic ligands have been shown to emit brightly in the blue region of the spectrum. Zinc(II) complexes bearing derivatized imidazoles have been explored for possible optoelectronic applications. The structures of two zinc(II) complexes of 5,6-dimethyl-2-(pyridin-2-yl)-1-[(pyridin-2-yl)methyl]-1H-benzimidazole (L), namely dichlorido(dimethylformamide-κO){5,6-dimethyl-2-(pyridin-2-yl-κN)-1-[(pyridin-2-yl)methyl]-1H-benzimidazole-κN(3)}zinc(II) dimethylformamide monosolvate, [ZnCl2(C20H18N4)(C3H7NO)]·C3H7NO, (I), and bis(acetato-κ(2)O,O'){5,6-dimethyl-2-(pyridin-2-yl-κN)-1-[(pyridin-2-yl)methyl]-1H-benzimidazole-κN(3)}zinc(II) ethanol monosolvate, [Zn(C2H3O2)2(C20H18N4)]·C2H5OH, (II), are reported. Complex (I) crystallized as a dimethylformamide solvate and exhibits a distorted trigonal bipyramidal coordination geometry. The coordination sphere consists of a bidentate L ligand spanning axial to equatorial sites, two chloride ligands in equatorial sites, and an O-bound dimethylformamide ligand in the remaining axial site. The other complex, (II), crystallized as an ethanol solvate. The Zn(II) atom has a distorted trigonal prismatic coordination geometry, with two bidentate acetate ligands occupying two edges and a bidentate L ligand occupying the third edge of the prism. Complexes (I) and (II) emit in the blue region of the spectrum. The results of density functional theory (DFT) calculations suggest that the luminescence of L results from π*←π transitions and that the luminescence of the complexes results from interligand charge-transfer transitions. The orientation of the 2-(pyridin-2-yl) substituent with respect to the benzimidazole system was found to have an impact on

  9. Electrophilic alkylation of pseudotetrahedral nickel(II) arylthiolate complexes.

    PubMed

    Deb, Tapash; Jensen, Michael P

    2015-01-01

    A kinetic study is reported for reactions of pseudotetrahedral nickel(II) arylthiolate complexes [(Tp(R,Me))Ni-SAr] (Tp(R,Me) = hydrotris{3-R-5-methyl-1-pyrazolyl}borate, R = Me, Ph, and Ar = C6H5, C6H4-4-Cl, C6H4-4-Me, C6H4-4-OMe, 2,4,6-Me3C6H2, 2,4,6-(i)Pr3C6H2) with organic electrophiles R'X (i.e., MeI, EtI, BzBr) in low-polarity organic solvents (toluene, THF, chloroform, dichloromethane, or 1,2-dichloroethane), yielding a pseudotetrahedral halide complex [(Tp(R,Me))Ni-X] (X = Cl, Br, I) and the corresponding organosulfide R'SAr. Competitive reactions with halogenated solvents and adventitious air were also examined. Akin to reactions of analogous and biomimetic zinc complexes, a pertinent mechanistic question is the nature of the reactive nucleophile, either an intact thiolate complex or a free arylthiolate resulting from a dissociative pre-equilibrium. The observed kinetics conformed to a second-order rate law, first order with respect to the complex and electrophile, and no intermediate complexes were observed. In the absence of a mechanistically diagnostic rate law, a variety of mechanistic probes were examined, including kinetic effects of varying the metal, solvent, electrophile, and temperature, as well as the 3-pyrazolyl and arylthiolate substituents. Compared to zinc analogues, the effect of Ni-SAr covalency is also of interest herein. The results are broadly interpreted with respect to the disparate mechanistic pathways. PMID:25494529

  10. Macrocyclic nickel(II) complexes: Synthesis, characterization, superoxide scavenging activity and DNA-binding

    NASA Astrophysics Data System (ADS)

    Ramadan, Abd El-Motaleb M.

    2012-05-01

    A new series of nickel(II) complexes with the tetraaza macrocyclic ligand have been synthesized as possible functional models for nickel-superoxide dismutase enzyme. The reaction of 5-amino-3-methyl-1-phenylpyrazole-4-carbaldehyde (AMPC) with itself in the presence of nickel(II) ion yields, the new macrocyclic cationic complex, [NiL(NO3)2], containing a ligand composed of the self-condensed AMPC (4 mol) bound to a single nickel(II) ion. A series of metathetical reactions have led to the isolation of a number of newly complexes of the types [NiL]X2; X = ClO4 and BF4, [NiLX2], X = Cl and Br (Scheme 1). Structures and characterizations of these complexes were achieved by several physicochemical methods namely, elemental analysis, magnetic moment, conductivity, and spectral (IR and UV-Vis) measurements. The electrochemical properties and thermal behaviors of these chelates were investigated by using cyclic voltammetry and thermogravimetric analysis (TGA and DTG) techniques. A distorted octahedral stereochemistry has been proposed for the six-coordinate nitrato, and halogeno complexes. For the four-coordinate, perchlorate and fluoroborate, complex species a square-planar geometry is proposed. The measured superoxide dismutase mimetic activities of the complexes indicated that they are potent NiSOD mimics and their activities are compared with those obtained previously for nickel(II) complexes. The probable mechanistic implications of the catalytic dismutation of O2rad - by the synthesized nickel(II) complexes are discussed. The DNA-binding properties of representative complexes [NiLCl2] and [NiL](PF4)2 have been investigated by the electronic absorption and fluorescence measurements. The results obtained suggest that these complexes bind to DNA via an intercalation binding mode and the binding affinity for DNA follows the order: [NiLCl2] □ [NiL](PF4)2.

  11. The Synthesis of Copper(II) Carboxylates Revisited

    ERIC Educational Resources Information Center

    Kushner, Kevin; Spangler, Robert E.; Salazar, Ralph A., Jr.; Lagowski, J. J.

    2006-01-01

    An electrochemical synthesis of copper(II) carboxylates has been developed and used in the general chemistry laboratory course for chemistry majors. This synthesis, using nonaqueous solutions, supplements the strategy of providing experiences in synthetic chemistry described by Yoder et al. ("J. Chem. Educ." 1995, 72, 267). (Contains 1 table.)

  12. Sonochemical synthesis and characterization of three nano zinc(II) coordination polymers; Precursors for preparation of zinc(II) oxide nanoparticles.

    PubMed

    Marandi, Farzin; Hashemi, Lida; Morsali, Ali; Krautscheid, Harald

    2016-09-01

    Nanostructures of three Zinc(II) coordination polymers, [Zn(NNO)2(H2O)4]n (1), [Zn(PNNO)2(H2O)2]n (2) and [Zn(H2O)6]·(INNO)2 (3) {NNO: Nicotinic acid N-oxide, PNNO: Picolinic acid N-oxide and INNO: Isonicotinic acid N-oxide}, have been synthesized by a sonochemical process and reaction of ligands with Zn(CH3COO)2. The Zinc(II) oxide nano-particles have been synthesized from thermolysis of [Zn(NNO)2(H2O)4]n (1), [Zn(PNNO)2(H2O)2]n (2) and [Zn(H2O)6]·(INNO)2 (3) at two different methods (with surfactant and without surfactant) and two temperatures (200 and 600°C). The ZnO nanoparticles were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Comparison of the SEM images of ZnO nano-particles at two different methods and temperatures shows that higher temperature results in an increasing of agglomeration and thus small and spherical ZnO particles with good separation were produced by thermolysis of compounds at 200°C and by use of surfactant. PMID:27150749

  13. Determining the Amount of Copper(II) Ions in a Solution Using a Smartphone

    ERIC Educational Resources Information Center

    Montangero, Marc

    2015-01-01

    When dissolving copper in nitric acid, copper(II) ions produce a blue-colored solution. It is possible to determine the concentration of copper(II) ions, focusing on the hue of the color, using a smartphone camera. A free app can be used to measure the hue of the solution, and with the help of standard copper(II) solutions, one can graph a…

  14. Synthesis of asymmetric zinc(II) phthalocyanines with two different functional groups & spectroscopic properties and photodynamic activity for photodynamic therapy.

    PubMed

    Göksel, Meltem

    2016-09-15

    Zinc(II) phthalocyanine containing [2-(tert-butoxycarbonyl)amino]ethoxy and iodine groups (A and B), as well as their deprotected mono-amino and tri-iodine zinc(II) phthalocyanine (2) were obtained. This structure surrounds by substituents with functional groups. From this perspective it can be used a starting material for many reactions and applications, such as sonogashira coupling, carbodiimide coupling. An example of a first diversification reaction of this compound was obtained with conjugation of a biotin. Asymmetrically biotin conjugated and heavy atom bearing zinc(II) phthalocyanine (3) were synthesized characterized for the first time and photophysical, photochemical and photobiological properties of these phthalocyanines were compared in this study. PMID:27423301

  15. Metal ion containing CXCR4 chemokine receptor antagonists: nickel(II) complexes of configurationally restricted macrocycles

    PubMed Central

    Smith, Rachel; Huskens, Dana; Daelemans, Dirk; Mewis, Ryan E.; Garcia, Courtney D.; Cain, Amy N.; Carder Freeman, TaRynn N.; Pannecouque, Christophe; De Clercq, Erik; Schols, Dominique; Hubin, Timothy J.

    2012-01-01

    Tetraazamacrocyclic complexes of transition metals provide useful units for incorporating multiple coordination interactions into a single protein binding molecule. They can be designed with available sites for protein interactions with donor atom containing amino acid side chains or have labile ligands such as H2O allowing facile exchange. Three configurationally restricted nickel(II) cyclam complexes with either one or two macrocyclic rings were synthesised and their ability to abrogate the CXCR4 chemokine receptor signalling process was assessed (IC50 = 8320, 194 and 14 nM). Analogues were characterised crystallographically to determine the geometric parameters of acetate binding as a model for aspartate. The most active nickel(II) compound was tested in several anti-HIV assays against representative viral strains showing highly potent EC50 values down to 13 nM against CXCR4 using viruses with no observed cellular cytotoxicity (CC50 > 125 μM). PMID:2289289

  16. Spectroscopic and biological studies on newly synthesized nickel(II) complexes of semicarbazones and thiosemicarbazones

    NASA Astrophysics Data System (ADS)

    Chandra, Sulekh; Gupta, Lokesh Kumar

    2005-12-01

    Nickel(II) complexes, having the general composition Ni(L) 2X 2, have been synthesized [where L: isopropyl methyl ketone semicarbazone (LLA), isopropyl methyl ketone thiosemicarbazone (LLB), 4-aminoacetophenone semicarbazone (LLC) and 4-aminoacetophenone thiosemicarbazone (LLD) and X = Cl -, 1/2SO 42-]. All the Ni(II) complexes reported here have been characterized by elemental analyses, magnetic moments, IR, electronic and mass spectral studies. All the complexes were found to have magnetic moments corresponding to two unpaired electrons. The possible geometries of the complexes were assigned on the basis of electronic and infrared spectral studies. Newly synthesized ligand and its nickel(II) complexes have been screened against different bacterial and fungal growth.

  17. Aspartate-Based CXCR4 Chemokine Receptor Binding of Cross-Bridged Tetraazamacrocyclic Copper(II) and Zinc(II) Complexes.

    PubMed

    Maples, Randall D; Cain, Amy N; Burke, Benjamin P; Silversides, Jon D; Mewis, Ryan E; D'huys, Thomas; Schols, Dominique; Linder, Douglas P; Archibald, Stephen J; Hubin, Timothy J

    2016-08-26

    The CXCR4 chemokine receptor is implicated in a number of diseases including HIV infection and cancer development and metastasis. Previous studies have demonstrated that configurationally restricted bis-tetraazamacrocyclic metal complexes are high-affinity CXCR4 antagonists. Here, we present the synthesis of Cu(2+) and Zn(2+) acetate complexes of six cross-bridged tetraazamacrocycles to mimic their coordination interaction with the aspartate side chains known to bind them to CXCR4. X-ray crystal structures for three new Cu(2+) acetate complexes and two new Zn(2+) acetate complexes demonstrate metal-ion-dependent differences in the mode of binding the acetate ligand concomitantly with the requisite cis-V-configured cross-bridged tetraazamacrocyle. Concurrent density functional theory molecular modelling studies produced an energetic rationale for the unexpected [Zn(OAc)(H2 O)](+) coordination motif present in all of the Zn(2+) cross-bridged tetraazamacrocycle crystal structures, which differs from the chelating acetate [Zn(OAc)](+) structures of known unbridged and side-bridged tetraazamacrocyclic Zn(2+) -containing CXCR4 antagonists. PMID:27458983

  18. Carbonic Anhydrase Inhibitors. Part 461 Inhibition of Carbonic Anhydrase Isozymes I, II and IV With Trifluoromethylsulfonamide Derivatives and Their Zinc(II) and Copper(II) Complexes

    PubMed Central

    Mincione, Giovanna; Scozzafava, Andrea

    1997-01-01

    Reaction of aromatic/heterocyclic sulfonamides containing a free amino group with triflic anhydride afforded compounds possessing trifluoromethanesulfonamido moieties in their molecule. The Zn(II) and Cu(II) complexes of these new sulfonamides were prepared and characterized by standard procedures (elemental analysis, spectroscopic, magnetic, thermogravimetric and conductimetric measurements). The new derivatives showed good inhibitory activity against three isozymes of carbonic anhydrase (CA), i.e., CA I, II and IV. PMID:18475762

  19. Pyochelin, a siderophore of Pseudomonas aeruginosa: physicochemical characterization of the iron(III), copper(II) and zinc(II) complexes.

    PubMed

    Brandel, Jérémy; Humbert, Nicolas; Elhabiri, Mourad; Schalk, Isabelle J; Mislin, Gaëtan L A; Albrecht-Gary, Anne-Marie

    2012-03-01

    Pseudomonas aeruginosa is an opportunistic pathogen, synthesizing two major siderophores, pyoverdine (Pvd) and pyochelin (Pch), to cover its needs in iron(III). If the high affinity and specificity of Pvd toward iron(III) (pFe = 27.0) was well described in the literature, the physicochemical and coordination properties of Pch toward biologically relevant metals (Fe(III), Cu(II) or Zn(II)) have been only scarcely investigated. We report a thorough physico-chemical investigation of Pch (potentiometry, spectrophotometries, ESI/MS) that highlighted its moderate but significantly higher affinity for Fe(3+) (pFe = 16.0 at p[H] 7.4) than reported previously. We also demonstrated that Pch strongly chelates divalent metals such as Zn(II) (pZn = 11.8 at p[H] 7.4) and Cu(II) (pCu = 14.9 at p[H] 7.4) and forms predominantly 1 : 2 (M(2+)/Pch) complexes. Kinetic studies revealed that the formation of the ferric Pch complexes proceeds through a Eigen-Wilkins dissociative ligand interchange mechanism involving two protonated species of Pch and the Fe(OH)(2+) species of Fe(III). Our physico-chemical parameters supports the previous biochemical studies which proposed that siderophores are not only devoted to iron(III) shuttling but most likely display other specific biological role in the subtle metals homeostasis in microorganisms. This work also represents a step toward deciphering the role of siderophores throughout evolution. PMID:22261733

  20. Synthesis, structure and spectroscopic properties of two new trinuclear nickel(II) clusters possessing solvent effect

    NASA Astrophysics Data System (ADS)

    Dong, Wen-Kui; Chen, Xiao; Sun, Yin-Xia; Yang, Yu-Hua; Zhao, Li; Xu, Li; Yu, Tian-Zhi

    2009-10-01

    Two solvent-induced trinuclear nickel(II) clusters, [{NiL(CH 3OH)} 2(OAc) 2Ni]·2CH 3OH ( I) and [{NiL(C 2H 5OH)} 2(OAc) 2Ni]·2C 2H 5OH ( II), have been synthesized by the reaction of a new Salen-type bisoxime chelating ligand of 5,5'-di( N, N'-diethylamino)-2,2'-[(1,3-propylene)dioxybis(nitrilomethylidyne)]diphenol (H 2L) with nickel(II) acetate tetrahydrate in different solvents. Clusters I and II were characterized by elemental analyses, IR spectra, UV-vis absorption spectra, TG-DTA and X-ray diffraction methods. In clusters I (or II), there are two ligand moieties (which provide N 2O 2 donors), two acetate ions, two coordinated methanol (or ethanol) molecules and two crystallizing methanol (or ethanol) molecules, which result in the formation of three slightly distorted octahedral geometries around Ni(II) ions. Interestingly, nickel(II) ions in the structures of clusters I and II are all six-coordinated geometry, but clusters I and II are grown up in different solvent. Right because of this, solvent effect cause to their different crystal structures.

  1. Nitric oxide and bcl-2 mediated the apoptosis induced by nickel(II) in human T hybridoma cells

    SciTech Connect

    Guan Fuqin; Zhang Dongmei; Wang Xinchang; Chen Junhui . E-mail: jhchen@nju.edu.cn

    2007-05-15

    Although effects of nickel(II) on the immune system have long been recognized, little is known about the effects of nickel(II) on the induction of apoptosis and related signaling events in T cells. In the present study, we investigated the roles and signaling pathways of nickel(II) in the induction of apoptosis in a human T cell line jurkat. The results showed that the cytotoxic effects of Ni involved significant morphological changes and chromosomal condensation (Hoechst 33258 staining). Analyses of hypodiploid cells and FITC-Annexin V and PI double staining showed significant increase of apoptosis in jurkat cells 6, 12 and 24 h after nickel(II) treatment. Flow cytometry analysis also revealed that the loss of mitochondrial membrane potential (MMP) occurred concomitantly with the onset of NiCl{sub 2}-induced apoptosis. Induction of apoptotic cell death by nickel was mediated by reduction of bcl-2 expression. Furthermore, nickel stimulated the generation of nitric oxide (NO). These results suggest that nickel(II) chloride induces jurkat cells apoptosis via nitric oxide generation, mitochondrial depolarization and bcl-2 suppression.

  2. Mononuclear thiocyanate containing nickel(II) and binuclear azido bridged nickel(II) complexes of N4-coordinate pyrazole based ligand: Syntheses, structures and magnetic properties

    NASA Astrophysics Data System (ADS)

    Solanki, Ankita; Monfort, Montserrat; Kumar, Sujit Baran

    2013-10-01

    Two mononuclear nickel(II) complexes [NiL1(NCS)2] (1) and [NiL2(NCS)2] (2) and two azido bridged binuclear nickel(II) complexes [Ni(()2()2] (3) and [Ni(()2()2] (4), where L1, L2, L1‧ and L2‧ are N,N-diethyl-N‧,N‧-bis((3,5-dimethyl-1H-pyrazol-1-yl)methyl)ethane-1,2-diamine (L1), N,N-bis((1H-pyrazol-1-yl)methyl)-N‧,N‧-diethylethane-1,2-diamine (L2), N,N-diethyl-N‧-((3,5-dimethyl-1H-pyrazol-1-yl)methyl)ethane-1,2-diamine (L1‧) and N-((1H-pyrazol-1-yl)methyl)-N‧,N‧-diethylethane-1,2-diamine (L2‧) have been synthesized and characterized by microanalyses and physico-chemical methods. Single crystal X-ray diffraction analyses revealed that complexes 1 and 2 are mononuclear NCS- containing Ni(II) complex with octahedral geometry and complexes 3 and 4 are end-on (μ-1,1) azido bridged binuclear Ni(II) complexes with distorted octahedral geometry. Variable temperature magnetic studies of the complexes 3 and 4 display ferromagnetic interaction with J values 19 and 32 cm-1, respectively.

  3. Carbene formation upon reactive dissolution of metal oxides in imidazolium ionic liquids.

    PubMed

    Wellens, Sil; Brooks, Neil R; Thijs, Ben; Meervelt, Luc Van; Binnemans, Koen

    2014-03-01

    Metal oxides were found to dissolve in different imidazolium ionic liquids with a hydrogen atom in the C2 position of the imidazolium ring, but not if a methyl substituent was present in the C2 position. The crystal structure of the product that crystallised from an ionic liquid containing dissolved silver(i) oxide showed that this was a silver(i) carbene complex. The presence of carbenes in solution was proven by (13)C NMR spectroscopy and the reactions were also monitored by Raman spectroscopy. The dissolution of other metal oxides, namely copper(ii) oxide, zinc(ii) oxide and nickel(ii) oxide, was also studied in imidazolium ionic liquids and it was found that stable zinc(ii) carbenes were formed in solution, but these did not crystallise under the given experimental conditions. A crystalline nickel(ii) carbene complex could be obtained from a solution of nickel(ii) chloride dissolved in a mixture of 1-butyl-3-methylimidazolium and 1-ethyl-3-methylimidazolium acetate. PMID:24390601

  4. Spectra and DNA-binding affinities of Copper(II), Nickel(II) complexes with a novel glycine Schiff base derived from chromone

    NASA Astrophysics Data System (ADS)

    Qin, Dong-dong; Yang, Zheng-yin; Wang, Bao-dui

    2007-11-01

    New [CuL·(H 2O) 3]NO 3·H 2O and [NiL·H 2O]NO 3·2H 2O complexes with Schiff base (LNa) derived from 6-hydroxy-3-carbaldehyde chromone (CDC) and glycine are reported. Two complexes have been characterized by elemental analysis, IR data, TG/DTA and molar conductivity. The binding of these two complexes to calf thymus DNA (CT-DNA) has been investigated, respectively, with UV-vis spectroscopy, fluorescence spectroscopy and viscosity measurements. The experiment results indicate that the two complexes may bind to CT-DNA through an intercalative mode and [CuL·(H 2O) 3]NO 3·H 2O intercalates into DNA more deeply than [NiL·H 2O]NO 3·2H 2O. Their intrinsic binding constants ( K) with DNA are 6.08 × 10 5 and 2.76 × 10 5 M -1.

  5. EPR, magnetic and spectral studies of copper(II) and nickel(II) complexes of schiff base macrocyclic ligand derived from thiosemicarbazide and glyoxal

    NASA Astrophysics Data System (ADS)

    Chandra, Sulekh; Sangeetika, X.

    2004-01-01

    A new macrocylic Schiff base 1,2,5,6,8,11-hexaazacyclododeca-7,12-dithione-2,4,8,10-tetraene(H 2L 4) containing thiosemicarbazone moiety is readily prepared and characterized for the first time with fairly good yield. Macrocylic ligand (H 2L 4) is prepared from the mesocyle 6-ethoxy-4-thio-2,3,5-triazine(H 2L 3) in ethanol with copper chloride acting as template using high dilution technique. The complexes of macrocylic ligand with a general composition M(H 2L 4)X 2 [where M=Cu(II) or Ni(II); H 2L 4=1,2,5,6,8,11-hexaazacyclo dodeca-7,12-dithione-2,4,8,10-tetraene; X= Cl -, NO 3-, 1/ 2SO 42-] and ML 4 (where metal salt used to synthesize complex is copper acetate and nickel thiocyanate) have been synthesized. The complexes were characterized on the basis of elemental analysis, molar conductance, magnetic susceptibility, IR, electronic, 1H NMR, mass and EPR spectral studies. The complexes from H 2L 4 show different stoichiometry ratio and with a variable grade of deprotonation in the ligand, depending upon the salt used and working conditions.

  6. Cinnamaldehyde and cuminaldehyde thiosemicarbazones and their copper(II) and nickel(II) complexes: a study to understand their biological activity.

    PubMed

    Bisceglie, Franco; Pinelli, Silvana; Alinovi, Rossella; Goldoni, Matteo; Mutti, Antonio; Camerini, Alessandro; Piola, Lorenzo; Tarasconi, Pieralberto; Pelosi, Giorgio

    2014-11-01

    This paper reports the synthesis and characterization of trans-cinnamaldehyde thiosemicarbazone (Htcin), cuminaldehyde thiosemicarbazone (Htcum) and their copper and nickel complexes. All the compounds, which on healthy cells (human fibroblasts) show a neglectable cytotoxicity, were screened in vitro in cell line U937 for their antileukemic activity. These compounds, in spite of their molecular similarity, present variegated behaviors. Htcin shows no inhibition activity in U935 cells, while both its metal complexes inhibit proliferation with IC50 at μM concentrations. The other ligand, Htcum, and its metal complexes, besides inhibiting proliferation, induce apoptosis. The cell cycle analysis highlights a G2/M checkpoint stop suggesting a possible direct action on DNA or on topoisomerase IIa. From CD and UV spectroscopy experiments, the DNA results to be not the main target of all these molecules, while both copper complexes are effective topoisomerase IIa inhibitors. All of these molecules activate caspase-9 and caspase-3, while caspase-8 activity is significantly induced by both cinnamaldehyde metal complexes. Tests on PgP and intracellular metal concentrations (determined by mean of atomic absorption spectrometry) show that the compounds tend to accumulate in the cytoplasm and that the cells do not manage to pump out copper and nickel ions. PMID:25108184

  7. Crystal structures of copper(II) and nickel(II) nitrate and chloride complexes with 4-bromo-2-[(2-hydroxyethylimino)-methyl]phenol

    SciTech Connect

    Chumakov, Yu. M.; Tsapkov, V. I.; Filippova, I. G.; Bocelli, G.; Gulea, A. P.

    2008-07-15

    The crystal structures of {l_brace}4-bromo-2-[(2-hydroxyethylimino)-methyl]phenolo{r_brace}aquacopper(II) nitrate hemihydrate (I), chloro-{l_brace}4-bromo-2-[(2-hydroxyethylimino)-methyl]phenolo{r_brace}copper hemihydrate (II), and chloro-{l_brace}4-bromo-2-[(2-hydroxyethylimino)-methyl]phenolo{r_brace}aquanickel (III) are determined using X-ray diffraction. Crystals of compound I are formed by cationic complexes, nitrate ions, and solvate water molecules. In the cation, the copper atom coordinates the singly deprotonated molecule of tridentate azomethine and the water molecule. The copper complexes are joined into centrosymmetric dimers by the O{sub w}-H...O hydrogen bonds. The crystal structure of compound II is composed of binuclear copper complexes and solvate water molecules. The copper atom coordinates the O,N,O ligand molecule and the chlorine ion, which fulfills a bridging function. The coordination polyhedron of the metal atom is a distorted tetragonal bipyramid in which the vertex is occupied by the chlorine atom of the neighboring complex in the dimer. Compound III is a centrosymmetric dimer complex. The coordination polyhedra of two nickel atoms related via the inversion center are distorted octahedra shared by the edge.

  8. Nickel(II) and copper(II) coordination polymers with 1,2-bis(tetrazol-1-yl)ethane and thiocyanate: Structure, supramolecular isomerism and magnetism

    NASA Astrophysics Data System (ADS)

    Liu, Pei-Pei; Wang, Yan-Qin; Tian, Chun-Yan; Peng, Hui-Qi; Gao, En-Qing

    2009-02-01

    Two heteroleptic coordination polymers with the flexible 1,2-bis(tetrazol-1-yl)ethane (btze) ligand, [Ni(btze) 2(SCN) 2] n ( 1) and [Cu(btze)(SCN) 2] n ( 2), have been synthesized in presence of thiocyanate. Compound 1 is composed of 1D chains with double btze bridges in the V-shaped gauche conformation, while 2 exhibits 2D coordination networks in which 1D chains with double N, S-thiocyanate bridges are cross-linked by btze bridges in the Z-shaped transoid conformation. In both compounds, the coordination motifs are stacked into 3D architectures through S···S and C-H···N interactions. The structures of 1 and a previously reported compound illustrate an interesting type of supramolecular isomerism. The two isomers exhibit almost identical 1D coordination structure and 2D hydrogen bonded superstructure, and the difference lies only in the interlayer packing associated with S···S contacts. Compound 2 exhibits weak antiferromagnetic interactions with J = 0.29 cm -1, consistent with the structural observation that the thiocyanate bridge adopts an equatorial-axial disposition between Cu(II) ions.

  9. High acetylene/ethylene separation in a microporous zinc(II) metal-organic framework with low binding energy.

    PubMed

    Wen, Hui-Min; Li, Bin; Wang, Hailong; Krishna, Rajamani; Chen, Banglin

    2016-01-21

    A novel zinc(II) metal-organic framework UTSA-67a with narrow one-dimensional (1D) pore channels and inner cages of moderate size has been developed for highly selective separation of C2H2/C2H4 mixtures at room temperature. PMID:26597048

  10. Kinetic effect of zinc(II) and cadmium(II) ions on configurational inversion of deltaLLL-fac(S)-tris(L-cysteinato-N,S)cobalt(III) complex.

    PubMed

    Aizawa, S; Ohishi, Y; Yamada, S; Nakamura, M

    2001-02-01

    It has been confirmed from circular dichroism (CD) spectral changes of aqueous solutions of deltaLLL-fac(S)-[Co(L-cys-N,S)3]3- that the absolute configurational inversion to the ALLL isomer is remarkably accelerated by zinc(II), while it is retarded by cadmium(II). In the diluted solutions of these metal ions containing excess deltaLLL-fac(S)-[Co(L-cys-N,S)3]3-, the observed inversion rate constant linearly depends on the zinc(II) concentration with an intercept, while it is not affected by the cadmium(II) concentration. The kinetic behavior has been explained by difference between zinc(II)- and cadmium(II)-interactions with lone pairs on sulfur donor atoms of fac(S)-[Co(L-cys-N,S)3]3-. It has also been proposed that concentrations of zinc(II) and cadmium(II) can be simultaneously determined by the kinetic measurements. PMID:11990552

  11. The Nature of the Ground States of Cobalt(II) and Nickel(II) Carboxypeptidase A

    PubMed Central

    Rosenberg, Robert C.; Root, Charles A.; Wang, Run-Han; Cerdonio, Massimo; Gray, Harry B.

    1973-01-01

    The magnetic susceptibilities of cobalt(II) and nickel(II) derivaties of carboxypeptidase A (CPA) follow the Curie law over a wide temperature range. The observed magnetic moments of Co(II)CPA and Ni(II)CPA are 4.77 ± 0.15 and 2.53 ± 0.10 Bohr Magnetons, respectively. The magnetic and spectral properties of Ni(II)CPA are consistent only with an octahedral ground-state geometry, whereas Co(II)CPA has a probable five-coordinate structure. The results establish ordinary metal-ion ground states for two metallocarboxypeptidase A derivatives which exhibit full peptidase activity. PMID:4509646

  12. Synthesis, spectroscopic characterization, electrochemical behaviour and thermal decomposition studies of some transition metal complexes with an azo derivative

    NASA Astrophysics Data System (ADS)

    Sujamol, M. S.; Athira, C. J.; Sindhu, Y.; Mohanan, K.

    2010-01-01

    Complexes of manganese(II), cobalt(II), nickel(II), copper(II) and zinc(II) with a novel heterocyclic azo derivative, formed by coupling diazotized 2-amino-3-carbethoxy-4,5-dimethylthiophene with acetylacetone were synthesized and characterized on the basis of elemental analyses, molar conductance, magnetic susceptibility measurements, UV-vis, IR, 1H NMR and EPR spectral data. Spectral studies revealed that the ligand existed in an internally hydrogen bonded azo-enol form rather than the keto-hydrazone form and coordinated to the metal ion in a tridentate fashion. Analytical data revealed that all the complexes exhibited 1:1 metal-ligand ratio. On the basis of electronic spectral data and magnetic susceptibility measurements, suitable geometry was proposed for each complex. The nickel(II) complex has undergone facile transesterification reaction when refluxed in methanol for a long period. The ligand and the copper(II) complex were subjected to X-ray diffraction study. The electrochemical behaviour of copper(II) complex was investigated by cyclic voltammetry. The thermal behaviour of the same complex was also examined by thermogravimetry.

  13. Synthesis, spectroscopic characterization, electrochemical behaviour and thermal decomposition studies of some transition metal complexes with an azo derivative.

    PubMed

    Sujamol, M S; Athira, C J; Sindhu, Y; Mohanan, K

    2010-01-01

    Complexes of manganese(II), cobalt(II), nickel(II), copper(II) and zinc(II) with a novel heterocyclic azo derivative, formed by coupling diazotized 2-amino-3-carbethoxy-4,5-dimethylthiophene with acetylacetone were synthesized and characterized on the basis of elemental analyses, molar conductance, magnetic susceptibility measurements, UV-vis, IR, (1)H NMR and EPR spectral data. Spectral studies revealed that the ligand existed in an internally hydrogen bonded azo-enol form rather than the keto-hydrazone form and coordinated to the metal ion in a tridentate fashion. Analytical data revealed that all the complexes exhibited 1:1 metal-ligand ratio. On the basis of electronic spectral data and magnetic susceptibility measurements, suitable geometry was proposed for each complex. The nickel(II) complex has undergone facile transesterification reaction when refluxed in methanol for a long period. The ligand and the copper(II) complex were subjected to X-ray diffraction study. The electrochemical behaviour of copper(II) complex was investigated by cyclic voltammetry. The thermal behaviour of the same complex was also examined by thermogravimetry. PMID:19910244

  14. Neutral nickel(II) phthalocyanine as a stable catalyst for visible-light-driven hydrogen evolution from water.

    PubMed

    Yuan, Yong-Jun; Tu, Ji-Ren; Lu, Hong-Wei; Yu, Zhen-Tao; Fan, Xiao-Xing; Zou, Zhi-Gang

    2016-01-28

    Neutral nickel(ii) phthalocyanine was found to be an efficient and stable catalyst for photocatalytic H2 evolution from water when coupled with an iridium complex as the photosensitizer and triethanolamine as the sacrificial electron donor. The result shows that the Ni-N sigma bond can enhance the stability of the catalyst. PMID:26743686

  15. Syntheses, characterization and antifungal activity of heteroleptic nickel(II) complexes with N-alkylsulfonyldithiocarbimates and phosphines

    NASA Astrophysics Data System (ADS)

    Vidigal, Antonio E. C.; Rubinger, Mayura M. M.; Oliveira, Marcelo R. L.; Guilardi, Silvana; Souza, Rafael A. C.; Ellena, Javier; Zambolim, Laércio

    2016-06-01

    Four nickel(II) complexes of general formula [Ni(RSO2Ndbnd CS2) (PPh3)2] where R = CH3 (2a), CH3CH2 (2b), CH3(CH2)3 (2c) and CH3(CH2)7 (2d) and PPh3 = triphenylphosphine; and two nickel(II) complexes of general formula [Ni(RSO2Ndbnd CS2)dppe] where R = CH3(CH2)3 (3c) and CH3(CH2)7 (3d) and dppe = 1,2-bis(diphenylphosphine)ethane) were prepared. These new complexes were obtained by the reaction of nickel(II) chloride hexahydrate with potassium N-alkylsulfonyldithiocarbimates and the appropriate phosphine using ethanol/water as solvent. The IR, UV-Vis and 1H, 13C and 31P NMR spectra, elemental analysis of Ni and the HR-ESI-MS were consistent with the formation of square planar nickel(II) complexes with mixed ligands. The structures of the compounds 2b and 2c were determined by single crystal X-ray diffraction. The compounds are isostructural and crystallize in the space group P 1 bar of the triclinic system. The activities of the complexes were investigated in vitro against Botrytis cinerea, Colletotrichum acutatum and Alternaria solani, fungi species that affect various commercially important plants. All the complexes were active.

  16. Electronic Transitions as a Probe of Tetrahedral versus Octahedral Coordination in Nickel(II) Complexes: An Undergraduate Inorganic Chemistry Experiment.

    ERIC Educational Resources Information Center

    Filgueiras, Carlos A. L.; Carazza, Fernando

    1980-01-01

    Discusses procedures, theoretical considerations, and results of an experiment involving the preparation of a tetrahedral nickel(II) complex and its transformation into an octahedral species. Suggests that fundamental aspects of coordination chemistry can be demonstrated by simple experiments performed in introductory level courses. (Author/JN)

  17. Adsorptive removal of nickel(II) ions from aqueous environment: A review.

    PubMed

    Raval, Nirav P; Shah, Prapti U; Shah, Nisha K

    2016-09-01

    Among various methods adsorption can be efficiently employed for the treatment of heavy metal ions contaminated wastewater. In this context the authors reviewed variety of adsorbents used by various researchers for the removal of nickel(II) ions from aqueous environment. One of the objectives of this review article is to assemble the scattered available enlightenment on a wide range of potentially effective adsorbents for nickel(II) ions removal. This work critically assessed existing knowledge and research on the uptake of nickel by various adsorbents such as activated carbon, non-conventional low-cost materials, nanomaterials, composites and nanocomposites. The system's performance is evaluated with respect to the overall metal removal and the adsorption capacity. In addition, the equilibrium adsorption isotherms, kinetics and thermodynamics data as well as various optimal experimental conditions (solution pH, equilibrium contact time and dosage of adsorbent) of different adsorbents towards Ni(II) ions were also analyzed. It is evident from a literature survey of more than 190 published articles that agricultural solid waste materials, natural materials and biosorbents have demonstrated outstanding adsorption capabilities for Ni(II) ions. PMID:27149285

  18. Nickel(II) adsorption onto biomass based activated carbon obtained from sugarcane bagasse pith.

    PubMed

    Krishnan, K Anoop; Sreejalekshmi, K G; Baiju, R S

    2011-11-01

    Bioavailability of Nickel in the form of hydrated Nickel(II) attributes to its toxicological effects and hence its removal from aqueous solution is of great concern. Adsorption is used as an efficient technique for the removal of Nickel(II), hereafter Ni(II), from water and wastewaters. Activated carbon obtained from sugarcane bagasse pith (SBP-AC), a waste biomass collected from juice shops in Sarkara Devi Temple, Chirayinkeezhu, Trivandrum, India during annual festival, is used as adsorbent in the study. The process of adsorption is highly dependent on solution pH, and maximum removal occurs in the pH range of 4.0-8.0. Moreover, the amount of Ni(II) adsorbed onto SBP-AC increased with the time increase and reached equilibrium at 4h. Adsorption kinetic and equilibrium data were analyzed for determining the best fit kinetic and isotherm models. The overall study reveals the potential value of steam pyrolysed SBP-AC as a possible commercial adsorbent in wastewater treatment strategies. PMID:21924900

  19. Photo-induced electron transfer between a dendritic zinc(II) phthalocyanine and methyl viologen

    NASA Astrophysics Data System (ADS)

    Wang, Yuhua; Chen, Jiangxu; Huang, Lishan; Xie, Shusen; Yang, Hongqin; Peng, Yiru

    2013-01-01

    The intermolecular electron transfer between the carboxylic dendritic zinc(II) phthalocyanines [G1-ZnPc( and G2-ZnPc(] and methyl viologen (MV) is studied by steady-state fluorescence and UV/Vis absorption spectroscopic method. The effect of dendron generation of this series of dendritic phthalocyanines on intermolecular electron transfer is investigated. The results show that the fluorescence emission of these dendritic phthalocyanines could be greatly quenched by MV upon excitation at 610 nm. The Stern-Volmer constant (KSV) of electron transfer is decreased with increasing dendron generations. Our study suggests that these dendritic phthalocyanines are an effective new electron donor and transmission complex and could be used as a potential artificial photosynthesis system.

  20. The interaction of zinc(II) and hydroxamic acids and a metal-triggered Lossen rearrangement.

    PubMed

    Duchácková, Lucie; Roithová, Jana

    2009-12-14

    The structure and reactivity of a complex of zinc(II), water, acetic acid, and acetohydroxamic acid, in which one of the acids is deprotonated, is investigated by means of mass spectrometry, labeling studies, and density functional calculations to unravel the exceptional binding properties of hydroxamic acids towards zinc-containing enzymes at the molecular level. It is shown that acetohydroxamic acid is deprotonated in the complex, whereas acetic acid is present in its neutral form. The binding energies of the ligands towards zinc increase in the following order: water

  1. Zero thermal expansion in a flexible, stable framework : tetramethylammonium copper(I) zinc(II) cyanide.

    SciTech Connect

    Phillips, A. E.; Halder, G. J.; Chapman, K. W.; Goodwin, A. L.; Kepert, C. J.; Univ. Sydney; Univ. Cambridge

    2010-01-13

    Tetramethylammonium copper(I) zinc(II) cyanide, which consists of N(CH{sub 3}){sub 4}{sup +} ions trapped within a cristobalite-like metal cyanide framework, has been studied by variable-temperature powder and single-crystal X-ray diffraction. Its coefficient of thermal expansion is approximately zero over the temperature range 200-400 K and comparable with the best commercial zero thermal expansion materials. The atomic displacement parameters, apparent bond lengths, and structure of a low-temperature, low-symmetry phase reveal that the low-energy vibrational modes responsible for this behavior maintain approximately rigid Zn coordination tetrahedra but involve significant distortion of their Cu counterparts.

  2. Structural studies on acetophenone- and benzophenone-derived thiosemicarbazones and their zinc(II) complexes

    NASA Astrophysics Data System (ADS)

    Ferraz, Karina S. O.; Silva, Nayane F.; Da Silva, Jeferson G.; Speziali, Nivaldo L.; Mendes, Isolda C.; Beraldo, Heloisa

    2012-01-01

    In the present work N(3)- meta-chlorophenyl-(HAc3 mCl, 1) and N(3)- meta-fluorphenyl-(HAc3 mF, 2) acetophenone thiosemicarbazone, and N(3)- meta-chlorophenyl-(HBz3 mCl, 3) and N(3)- meta-fluorphenyl-(HBz3 mF, 4) benzophenone thiosemicarbazone were obtained, as well as their zinc(II) complexes [Zn(Ac3 mCl) 2] ( 5), [Zn(Ac3 mF) 2] ( 6), [Zn(Bz3 mCl) 2] ( 7) and [Zn(Bz3 mF) 2] ( 8). Upon re-crystallization in DMSO:acetone conversion of 8 into [Zn(Bz3 mF) 2]·(DMSO) ( 8a) occurred. The crystal structures of 2, 5 and 8a were determined.

  3. Dinuclear Zinc(II) Macrocyclic Complex as Receptor for Selective Fluorescence Sensing of Pyrophosphate.

    PubMed

    Mesquita, Lígia M; André, Vânia; Esteves, Catarina V; Palmeira, Tiago; Berberan-Santos, Mário N; Mateus, Pedro; Delgado, Rita

    2016-03-01

    A new diethylenetriamine-derived macrocycle known as L, bearing 2-methylquinoline arms and containing m-xylyl spacers, was prepared in good yield by a one-pot [2 + 2] Schiff base condensation procedure, followed by reduction with sodium borohydride. Up to now this is the first hexaazamacrocycle with appended fluorophore units. Single-crystal X-ray diffraction determination of the dinuclear zinc(II) complex of L showed that metal centers are located at about 7.20(2) Å from one another. This complex exhibits only weak fluorescence in aqueous solution, but the addition of 1 equiv of pyrophosphate (PPi) caused a 21-fold enhancement of the fluorescence intensity. The sensor response is linear up to a value of 10 μM HPPi(3-) and has a detection limit of 300 nM. The receptor behaves as a highly selective sensor for pyrophosphate as other anions, including phosphate, phenylphosphate (PhP), adenosine monophosphate (AMP), adenosine diphosphate (ADP), and adenosine triphosphate (ATP), failed to induce any fluorescence change and practically do not affect the fluorescence intensity of the sensor in the presence of HPPi(3-). Competition titrations carried out in aqueous solution at pH 7.4 [in 20 mM 3-(N-morpholino)propanesulfonic acid (MOPS) buffer] by spectrofluorometry revealed a high association constant value of 6.22 log units for binding of PPi by the dinuclear zinc(II) receptor, one of the highest reported values for colorimetric/fluorometric sensors able to work under real aqueous physiological conditions, while association constant values for binding of the other phosphorylated substrates are in the 5.51-4.03 log unit range. PMID:26871612

  4. Spectral studies of copper(II) complexes of 6-(3-thienyl) pyridine-2-thiosemicarbazone

    NASA Astrophysics Data System (ADS)

    Mahjoub, Omima Abdalla; Farina, Yang

    2014-09-01

    Two novel copper(II) complexes [Cu(HL)Cl]Cl˙H2O (1) and [Cu(L)NO3]˙H2O (2) of the three NNS donor thiosemicarbazone ligand 6-(3-thienyl) pyridine-2-thiosemicarbazone have been synthesized. The ligand and its copper(II) complexes were characterized by elemental analysis (C, H, N, and S), FT-IR, UV-visible, magnetic susceptibility and molar conductance. The thiosemicarbazone is present either as the thione form in complex 1 or as thiol form in complex 2 and is coordinated to copper(II) atom via the pyridine nitrogen atom, the azomethine nitrogen atom and the sulfur atom. The physicochemical and spectral data suggest square planar geometry for copper(II) atoms.

  5. A microcalorimetric study of the sorption of copper(II) on KB-4 carboxyl cationite

    NASA Astrophysics Data System (ADS)

    Zauer, E. A.

    2008-08-01

    The thermokinetics of sorption of copper(II) ions on KB-4 carboxyl cationite in the salt and hydrogen forms was studied microcalorimetrically. The total heat effect of sorption and its dependence on the degree of ionite filling were determined.

  6. Spectral studies of copper(II) complexes of 6-(3-thienyl) pyridine-2-thiosemicarbazone

    SciTech Connect

    Mahjoub, Omima Abdalla; Farina, Yang

    2014-09-03

    Two novel copper(II) complexes [Cu(HL)Cl]Cl.H{sub 2}O (1) and [Cu(L)NO{sub 3}]Ðœ‡H{sub 2}O (2) of the three NNS donor thiosemicarbazone ligand 6-(3-thienyl) pyridine-2-thiosemicarbazone have been synthesized. The ligand and its copper(II) complexes were characterized by elemental analysis (C, H, N, and S), FT-IR, UV-visible, magnetic susceptibility and molar conductance. The thiosemicarbazone is present either as the thione form in complex 1 or as thiol form in complex 2 and is coordinated to copper(II) atom via the pyridine nitrogen atom, the azomethine nitrogen atom and the sulfur atom. The physicochemical and spectral data suggest square planar geometry for copper(II) atoms.

  7. Spectroscopic characterization of copper(II) complexes of indoxyl N(4)-methyl thiosemicarbazone

    NASA Astrophysics Data System (ADS)

    Chandra, Sulekh; Kumar, Umendra

    2004-10-01

    New copper(II) complexes of indoxyl thiosemicarbazone (ITSC) of general composition CuL 2X 2 (where L: ITSC; X: Cl -, NO 3-, ClO 4-, NCS -) have been synthesized and characterized by elemental analysis, molar conductance, magnetic susceptibility measurements and spectral (electronic, IR, EPR, 1H NMR , Mass) studies. Cyclic voltammetry measurements show quasi-reversible Cu 2+/Cu 1+ couple. Various physico-chemical techniques suggest a tetragonal structure for these copper(II) complexes.

  8. The role of copper(II) in the aggregation of human amylin.

    PubMed

    Sinopoli, Alessandro; Magrì, Antonio; Milardi, Danilo; Pappalardo, Matteo; Pucci, Pietro; Flagiello, Angela; Titman, Jeremy J; Nicoletti, Vincenzo Giuseppe; Caruso, Giuseppe; Pappalardo, Giuseppe; Grasso, Giuseppe

    2014-10-01

    Amylin is a 37-residue peptide hormone produced by the islet β-cells of pancreas and the formation of amylin aggregates is strongly associated with β-cell degeneration in type 2 diabetes, as demonstrated by more than 95% of patients exhibiting amylin amyloid upon autopsy. It is widely recognized that metal ions such as copper(II) have been implicated in the aggregation process of amyloidogenic peptides such as Aβ and α-synuclein and there is evidence that amylin self-assembly is also largely affected by copper(II). For this reason, in this work, the role of copper(II) in the aggregation of amylin has been investigated by several different experimental approaches. Mass spectrometric investigations show that copper(II) induces significant changes in the amylin structure, which decrease the protein fibrillogenesis as observed by ThT measurements. Accordingly, solid-state NMR experiments together with computational analysis carried out on a model amylin fragment confirmed the non-fibrillogenic nature of the copper(II) induced aggregated structure. Finally, the presence of copper(II) is also shown to have a major influence on amylin proneness to be degraded by proteases and cytotoxicity studies on different cell cultures are reported. PMID:25080969

  9. Synthesis and structural characterization of zinc(II) and cobalt(II) complexes based on multidentate hydrazone ligands

    NASA Astrophysics Data System (ADS)

    Li, Li; Zhang, Yuan Zhuo; Liu, E.; Yang, Chengxiong; Golen, James A.; Rheingold, Arnold L.; Zhang, Guoqi

    2016-04-01

    Two multidentate Schiff base ligands containing a hydrazone unit have been synthesized and investigated for zinc(II) and cobalt(II) coordination chemistry. The reactions of the 4-pyridyl derived hydrazone ligand HL1 with zinc(II) or cobalt(II) salts gave three mononuclear complexes that were structurally characterized by X-ray diffraction analysis. The results revealed that the ligand could adopt different coordination modes when various counter anions were employed. While in the case that zinc dichloride was used as a metal salt a neutral mononuclear mono-ligand complex was formed, the deprotonation of hydrazone occurred when zinc(II) or cobalt(II) nitrate were present and two new isostructural mononuclear bis-ligand complexes were isolated. Modification of the hydrazone ligand with oxygen donors was found to have a significant impact on the ligand reactivity, and a similar reaction of H2L2 with cobalt(II) nitrate gave a protonated product of H2L2 without the incorporation of cobalt(II), which features a one-dimensional hydrogen-bonded network in the solid state.

  10. Syntheses, structural variations and fluorescence studies of two dinuclear zinc(II) complexes of a Schiff base ligand with an extended carboxylate side arm

    NASA Astrophysics Data System (ADS)

    Shit, Shyamapada; Sasmal, Ashok; Dhal, Piu; Rizzoli, Corrado; Mitra, Samiran

    2016-03-01

    A potentially tetradentate Schiff base ligand containing carboxylic acid group, HL, (E)-2-((pyridin-2-yl)methyleneamino)-5-chlorobenzoic acid is synthesized and characterized. Reaction of HL with hydrated zinc(II) trichloroacetate and zinc(II) trifluoroacetate under similar reaction condition yields two discrete dinuclear complexes, [Zn(L)(Cl)]2 (1) and [Zn(L)(CF3COO)]2 (2) and characterized by different physicochemical methods. Single crystal X-ray structural characterization reveals different ligating properties of the coordinated anionic ligand (L-) in its zinc(II) complexes. The side arm carboxylate of L- shows μ1,3-carboxylato-bridging mode in 1 and connects zinc(II) atoms in syn-anti fashion while it exhibits a μ1,1-carboxylato-bridging mode in 2. The metal ions display distorted square pyramidal geometries in both the structures and associated with different degrees of distortions. The fluorescence spectra of HL and its zinc(II) complexes recorded in methanol at room temperature which reveal the enhancement of emission intensity for the complexes compared to that of the free ligand. Thermogravimetric analyses (TGA) reveal high thermal stabilities of the complexes.

  11. Nickel(II) Oxide Solubility and Phase Stability in High Temperature Aqueous Solutions

    SciTech Connect

    S.E. Ziemniak; M.A. Goyette

    2003-03-17

    A platinum-lined, flowing autoclave facility was used to investigate the solubility behavior of nickel(II) oxide (NiO) in deoxygenated ammonium and sodium hydroxide solutions between 21 and 315 C. Solubilities were found to vary between 0.4 and 400 nanomolal (nm). The measured nickel ion solubilities were interpreted via a Ni(II) ion hydroxo- and amino-complexing model and thermodynamic functions for these equilibria were obtained from a least-squares analysis of the data. Two solid phase transformations were observed: at temperatures below 149 C, the activity of Ni(II) ions in aqueous solution was controlled by a hydrous Ni(II) oxide (theophrastite) solid phase rather than anhydrous NiO (bunsenite); above 247 C, Ni(II) activities were controlled by cubic rather than rhombohedral bunsenite.

  12. Synthesis and structural characterization of two half-sandwich nickel(II) complexes with the scorpionate ligands

    SciTech Connect

    Wang, G.-F. E-mail: s-shuwen@163.com; Zhang, X.; Sun, S.-W.; Sun, H.; Ma, H.-X.

    2015-12-15

    The synthesis and characterization of two new halfsandwich mononuclear nickel(II) complexes with the scorpionate ligands, [k{sup 3}-N, N',N''-Tp{sup t-Bu}, {sup Me}NiI] (1) and [k{sup 3}-N,N',N''-Tp{sup t-Bu}, {sup Me}NiNO{sub 3}] (2), are reported. These complexes have been fully characterized by elemental analyses and infrared spectra. Their molecular structures were determined by single crystal X-ray diffraction. The nickel(II) ion of complex 1 is in a four-coordinate environment, in which the donor atoms are provided by three nitrogen atoms of a hydrotris(pyrazolyl) borate ligand and one iodide atom, while that of complex 2 is in a five-coordinate environment with three nitrogen atoms from a hydrotris(pyrazolyl)borate ligand and two oxygen atoms from a nitrate ion.

  13. Synthesis and structural characterization of two half-sandwich nickel(II) complexes with the scorpionate ligands

    NASA Astrophysics Data System (ADS)

    Wang, G.-F.; Zhang, X.; Sun, S.-W.; Sun, H.; Ma, H.-X.

    2015-12-01

    The synthesis and characterization of two new halfsandwich mononuclear nickel(II) complexes with the scorpionate ligands, [ k 3- N, N', N''- Tp t-Bu, Me NiI] ( 1) and [ k 3- N, N', N''- Tp t-Bu, Me NiNO3] ( 2), are reported. These complexes have been fully characterized by elemental analyses and infrared spectra. Their molecular structures were determined by single crystal X-ray diffraction. The nickel(II) ion of complex 1 is in a four-coordinate environment, in which the donor atoms are provided by three nitrogen atoms of a hydrotris(pyrazolyl) borate ligand and one iodide atom, while that of complex 2 is in a five-coordinate environment with three nitrogen atoms from a hydrotris(pyrazolyl)borate ligand and two oxygen atoms from a nitrate ion.

  14. Binding and photocleavage of a neutral nickel(II) bis(hydrogen pyridine-2,6-dicarboxylato) complex to DNA

    NASA Astrophysics Data System (ADS)

    Wang, Qingxiang; Li, Wenqi; Liu, Aifeng; Zhang, Bin; Gao, Feng; Li, Shunxing; Liao, Xiaolei

    2011-01-01

    A neutral nickel(II) bis(pyridine-2,6-dicarboxylato) complex, [Ni(Hdipic -) 2] (Hdipic - = monohydricsalt of pyridine-2,6-dicarboxylic acid) was synthesized and its interaction with DNA were comprehensively investigated by electronic absorption spectroscopy, viscosity, fluorescence, melting temperature and gel electrophoresis measurements in this paper. Spectrophotometric titration suggested that the nickel(II) complex could intercalatively bind to DNA via the planar dipicolinic acid moiety with a moderate binding strength of 1.6 × 10 4 M -1, and these results were further proved by the systematic studies of viscosity, ethidium bromide (EB) displacement and melting temperature experiments. Moreover, agarose gel electrophoresis assays showed that [Ni(Hdipic -) 2] had obvious photocleavage property for the supercoiled plasmid pBR322 DNA under 302 nm irradiation for 30 min, which allow us to postulate the studied complex as a proper candidate for photocleavage reagent.

  15. A Noble-Metal-Free Nickel(II) Polypyridyl Catalyst for Visible-Light-Driven Hydrogen Production from Water.

    PubMed

    Yuan, Yong-Jun; Lu, Hong-Wei; Tu, Ji-Ren; Fang, Yong; Yu, Zhen-Tao; Fan, Xiao-Xing; Zou, Zhi-Gang

    2015-10-01

    The complex [Ni(bpy)3](2+) (bpy=2,2'-bipyridine) is an active catalyst for visible-light-driven H2 production from water when employed with [Ir(dfppy)2 (Hdcbpy)] [dfppy=2-(3,4-difluorophenyl)pyridine, Hdcbpy=4-carboxy-2,2'-bipyridine-4'-carboxylate] as the photosensitizer and triethanolamine as the sacrificial electron donor. The highest turnover number of 520 with respect to the nickel(II) catalyst is obtained in a 8:2 acetonitrile/water solution at pH 9. The H2 -evolution system is more stable after the addition of an extra free bpy ligand, owing to faster catalyst regeneration. The photocatalytic results demonstrate that the nickel(II) polypyridyl catalyst can act as a more effective catalyst than the commonly utilized [Co(bpy)3 ](2+). This study may offer a new paradigm for constructing simple and noble-metal-free catalysts for photocatalytic hydrogen production. PMID:26264140

  16. Investigation of the photophysical and photochemical properties of peripherally tetra-substituted water-soluble zwitterionic and cationic zinc(ii) phthalocyanines.

    PubMed

    Çolak, Senem; Durmuş, Mahmut; Yıldız, Salih Zeki

    2016-06-21

    In this study, 4-{4-[N-((3-dimethylamino)propyl)amide]phenoxy}phthalonitrile () and its zinc(ii) phthalocyanine derivative () were synthesized for the first time. 4-(N-((3-Dimethylamino)propyl)amide)phenoxy substituted zinc(ii) phthalocyanine () was converted to its water-soluble sulfobetaine (), betaine () and N-oxide () containing zwitterionic and quaternized cationic () derivatives. All newly synthesized compounds () were characterized by the combination of UV-vis, FT-IR, (1)H NMR, mass spectroscopy techniques and elemental analysis. The photophysical (fluorescence quantum yields and lifetimes) and photochemical (singlet oxygen quantum yields) properties were investigated in DMSO for all the synthesized zinc(ii) phthalocyanines () and in both DMSO and aqueous solutions for zwitterionic and cationic phthalocyanines () for the specification of their capability as photosensitizers in photodynamic therapy (PDT). The binding behavior of water soluble phthalocyanines () to the bovine serum albumin protein was also examined for the determination of their transportation ability in the blood stream. PMID:27253970

  17. DNA binding, BSA interaction and SOD activity of two new nickel(II) complexes with glutamine Schiff base ligands.

    PubMed

    Wei, Qiang; Dong, Jianfang; Zhao, Peiran; Li, Manman; Cheng, Fengling; Kong, Jinming; Li, Lianzhi

    2016-08-01

    Two hexacoordinated octahedral nickel(II) complexes, [Ni(o-van-gln)(phen)(H2O)](1) and [Ni(sal-gln)(phen)(H2O)](2) [o-van-gln=a Schiff base derived from o-vanillin and glutamine, sal-gln=a Schiff base derived from salicylaldehyde and glutamine, phen=1,10-phenanthroline], have been synthesized and characterized by elemental analysis, IR spectra and single crystal X-ray diffraction. X-ray studies showed that nickel atoms of both 1 and 2 exhibit distorted NiN3O3 octahedral geometry. In each crystal, intermolecular hydrogen bonds form a two-dimensional network structure. DNA-binding properties of these two nickel(II) complexes were investigated by using UV-Vis absorption, fluorescence, circular dichroism (CD) spectroscopies and viscosity measurements. Results indicated that the two complexes can bind to calf thymus DNA (CT-DNA) via an intercalative mode, and complex 1 exhibits higher interaction with CT-DNA than complex 2. Furthermore, the interactions between the nickel(II) complexes with bovine serum albumin (BSA) have been studied by spectroscopies. The results indicated that both complexes could quench the intrinsic fluorescence of BSA in a static quenching process. The binding constants (Kb) and the numbers of binding sites (n) obtained are 1.10×10(5)M(-1) and 1.05 for complex 1 and 5.05×10(4)M(-1) and 0.997 for complex 2, respectively. Site-selective competitive binding investigation indicated that the binding sites of both the complexes are located in site I of sub-domains IIA of BSA. Assay of superoxide dismutase (SOD) activity of the nickel(II) complexes revealed that they exhibit significant superoxide scavenging activity with IC50=3.4×10(-5)M for complex 1 and 4.3×10(-5)M for complex 2, respectively. PMID:27295415

  18. Packed-bed column biosorption of chromium(VI) and nickel(II) onto Fenton modified Hydrilla verticillata dried biomass.

    PubMed

    Mishra, Ashutosh; Tripathi, Brahma Dutt; Rai, Ashwani Kumar

    2016-10-01

    The present study represents the first attempt to investigate the biosorption potential of Fenton modified Hydrilla verticillata dried biomass (FMB) in removing chromium(VI) and nickel(II) ions from wastewater using up-flow packed-bed column reactor. Effects of different packed-bed column parameters such as bed height, flow rate, influent metal ion concentration and particle size were examined. The outcome of the column experiments illustrated that highest bed height (25cm); lowest flow rate (10mLmin(-1)), lowest influent metal concentration (5mgL(-1)) and smallest particle size range (0.25-0.50mm) are favourable for biosorption. The maximum biosorption capacity of FMB for chromium(VI) and nickel(II) removal were estimated to be 89.32 and 87.18mgg(-1) respectively. The breakthrough curves were analyzed using Bed Depth Service Time (BDST) and Thomas models. The experimental results obtained agree to both the models. Column regeneration experiments were also carried out using 0.1M HNO3. Results revealed good reusability of FMB during ten cycles of sorption and desorption. Performance of FMB-packed column in treating secondary effluent was also tested under identical experimental conditions. Results demonstrated significant reduction in chromium(VI) and nickel(II) ions concentration after the biosorption process. PMID:27400422

  19. Synthesis of a labile sulfur-centred ligand, [S(H)C(PPh2S)2](-): structural diversity in lithium(i), zinc(ii) and nickel(ii) complexes.

    PubMed

    Thirumoorthi, Ramalingam; Chivers, Tristram; Häggman, Susanna; Mansikkamäki, Akseli; Morgan, Ian S; Tuononen, Heikki M; Lahtinen, Manu; Konu, Jari

    2016-08-01

    A high-yield synthesis of [Li{S(H)C(PPh2S)2}]2 [Li2·(3)2] was developed and this reagent was used in metathesis with ZnCl2 and NiCl2 to produce homoleptic complexes 4 and 5b in 85 and 93% yields, respectively. The solid-state structure of the octahedral complex [Zn{S(H)C(PPh2S)2}2] (4) reveals notable inequivalence between the Zn-S(C) and Zn-S(P) contacts (2.274(1) Å vs. 2.842(1) and 2.884(1) Å, respectively). Two structural isomers of the homoleptic complex [Ni{S(H)C(PPh2S)2}2] were isolated after prolonged crystallization processes. The octahedral green Ni(ii) isomer 5a exhibits the two monoprotonated ligands bonded in a tridentate (S,S',S'') mode to the Ni(ii) centre with three distinctly different Ni-S bond lengths (2.3487(8), 2.4500(9) and 2.5953(10) Å). By contrast, in the red-brown square-planar complex 5b the two ligands are S,S'-chelated to Ni(ii) (d(Ni-S) = 2.165(2) and 2.195(2) Å) with one pendant PPh2S group. DFT calculations revealed that the energetic difference between singlet and triplet state octahedral and square-planar isomers of the Ni(ii) complex is essentially indistinguishable. Consistently, VT and (31)P CP/MAS NMR spectroscopic investigations indicated that a mixture of isomers exists in solution at room temperature, while the singlet state square-planar isomer 5b becomes favoured at -40 °C. PMID:27453403

  20. Unprecedented Alkene Complex of Zinc(II): Structures and Bonding of Divinylzinc Complexes

    PubMed Central

    Wooten, Alfred; Carroll, Patrick J.; Maestri, Aaron G.

    2008-01-01

    This report describes the solid state structures of a series of divinylzinc complexes, one of which represents the only structurally characterized zinc(II) π-complex. Vinylzinc reagents, Zn[C(Me)=CH2]2 (1) and Zn[C(H)=CMe2]2 (2), have been synthesized and isolated as white crystalline solids in 66% and 72% yield, respectively. Each compound exhibits an infinite polymeric architecture in the solid state via a series of zinc-π (1) and zinc-σ-bonded (2) bridging interactions. Addition of chelating ligands to these divinylzinc compounds allowed isolation of the monomeric adducts (bipy)Zn[C(Me)=CH2]2 (1·bipy), (tmeda)Zn[C(Me)=CH2]2 (1·tmeda), (bipy)Zn[C(H)=CMe2]2 (2·bipy), and (tmeda)Zn[C(H)=CMe2]2 (2·tmeda), of which (1·bipy), (2·bipy), and (2·tmeda) have been characterized crystallography. PMID:16594699

  1. Photodynamic inactivation of Escherichia coli and Streptococcus mitis by cationic zinc(II) phthalocyanines in media with blood derivatives.

    PubMed

    Spesia, Mariana B; Rovera, Marisa; Durantini, Edgardo N

    2010-06-01

    The photodynamic inactivation (PDI) of Escherichia coli and Streptococcus mitis sensitized by cationic phthalocyanines was studied in different media containing blood derivatives. First, the activity of zinc(II) tetramethyltetrapyridino[3,4-b:3',4'-g:3'',4''-l:3''',4'''-q]porphyrazinium (ZnAPc4+), zinc(II) 2,9,16,23-tetrakis[4-(N-methylpyridyloxy)]phthalocyanine (ZnPPc4+) and zinc(II) 2,9,16,23-tetrakis[2-(N,N,N-trimethylamino)ethoxy]phthalocyanine (ZnEPc4+) were compared to photoinactivate these bacteria in saline solutions. After visible light irradiation, a higher photoinactivation of E. coli cells was found for ZnPPc4+, while ZnEPc4+ was the more effective sensitizer to eradicate S. mitis cells. In the presence of human red blood (HRB) cells, two aspects were analyzed: the photohemolysis induced by these cationic phthalocyanines and the PDI of bacteria in medium containing erythrocytes. The highest photohemolytic damage was produced by ZnPPc4+, which can be avoided using azida ion as photoprotective quencher. In both bacteria, the photoinactivation is possible in presence of HRB cells. Mainly, ZnEPc4+ is effective to photoinactivate S. mitis with a low hemolysis of erythrocytes. However, inactivation of E. coli by ZnPPc4+ decreases in medium with HRB cells, further when azide ion is added to avoid hemolysis. The presence of plasma considerable reduces the photocytotoxic effect, which mainly affects the eradication of E. coli. However, the PDI of S. mitis by ZnEPc4+ is even possible in presence of blood derivatives. PMID:20153568

  2. Human topoisomerase IB is a target of a thiosemicarbazone copper(II) complex.

    PubMed

    Vutey, Venn; Castelli, Silvia; D'Annessa, Ilda; Sâmia, Luciana B P; Souza-Fagundes, Elaine M; Beraldo, Heloisa; Desideri, Alessandro

    2016-09-15

    The human topoisomerase IB inhibition and the antiproliferative activity of 3-(4-bromophenyl)-1-pyridin-2-ylprop-2-en-1-one thiosemicarbazone HPyCT4BrPh alone and its copper(II) complex [Cu(PyCT4BrPh)Cl] was investigated. [Cu(PyCT4BrPh)Cl] inhibits both the DNA cleavage and religation step of the enzyme, whilst the ligand alone does not display any effect. In addition we show that coordination to copper(II) improves the cytotoxicity of HPyCT4BrPh against THP-1 leukemia and MCF-7 breast cancer cells. The data indicate that the copper(II) thiosemicarbazone complex may hit human topoisomerase IB and that metal coordination can be useful to improve cytotoxicity of this versatile class of compounds. PMID:27431056

  3. Photo-induced electron transfer between dendritic zinc(II) phthalocyanine bearing carboxylic terminal groups and methyl viologen

    NASA Astrophysics Data System (ADS)

    Wang, Yuhua; Chen, Jiangxu; Huang, Lishan; Xie, Shusen; Yang, Hongqin; Peng, Yiru

    2012-12-01

    The intermolecular electron transfer between carboxylic dendritic zinc(II) phthalocyanine bearing carboxylic terminal groups(G1-ZnPc(COOH)8) and methyl viologens (MV2+) was studied by steady-state fluorescence and UV/Vis spectroscopy. The effect of different concentrations of MV2+ on intermolecular electron transfer was investigated. The results show that the fluorescence emission of this dendritic phthalocyanine could be greatly quenched with an increasing amount of MV2+ upon excitation at 610 nm. Our study suggests that this novel dendritic phthalocyanine is an effective new electron donor and transmission complex and could be used as a potential biosensor conjugated with suitable fluorescence quencher.

  4. Calcium and magnesium interference studies for the binding of heavy metal ions in solution by Medicago sativa (alfalfa)

    SciTech Connect

    Gardea-Torresdey, J.L.; Tiemann, K.J.; Gonzalez, J.H.; Henning, J.A.; Townsend, M.S.

    1996-12-31

    Previous batch laboratory experiments performed to determine the potential ability of seven different varieties of Medicago sativa (alfalfa) revealed that the African shoots population was able to efficiently bind copper(II) and nickel(II) from aqueous solutions. Batch laboratory interference studies were performed with various calcium and magnesium concentrations (0.1 mM to 1 M) in order to ascertain the effects of these ions on the heavy metal binding ability of African alfalfa shoots. Results from these studies have shown that calcium and magnesium did not seriously reduce the binding of copper(II) and lead(II) to African alfalfa shoots. However, high concentrations of calcium and magnesium significantly reduced chromium(III), cadmium(II), nickel(II), and zinc(II) binding to African shoots. In addition, all these experiments were repeated maintaining the ionic strength constant, and similar results were obtained. Interference studies were also conducted in order to determine the effects of hard cations under flow conditions with silica-immobilized African alfalfa shoots. The information obtained from these studies will be useful for an innovative method of heavy metal ion removal and recovery from contaminated waters.

  5. Metal-based carboxamide-derived compounds endowed with antibacterial and antifungal activity.

    PubMed

    Hanif, Muhammad; Chohan, Zahid H; Winum, Jean-Yves; Akhtar, Javeed

    2014-08-01

    A series of three bioactive thiourea (carboxamide) derivatives, N-(dipropylcarbamothioyl)-thiophene-2-carboxamide (L(1)), N-(dipropylcarbamothioyl)-5-methylthiophene-2-carboxamide (L(2)) and 5-bromo-N-(dipropylcarbamothioyl)furan-2-carboxamide (L(3)) and their cobalt(II), copper(II), nickel(II) and zinc(II) complexes (1)-(12) have been synthesized and characterized by their IR,(1)H-NMR spectroscopy, mass spectrometry and elemental analysis data. The Crystal structure of one of the ligand, N-(dipropylcarbamothioyl)thiophene-2-carboxamide (L(1)) and its nickel(II) and copper(II) complexes were determined from single crystal X-ray diffraction data. All the ligands and metal(II) complexes have been subjected to in vitro antibacterial and antifungal activity against six bacterial species (Escherichia coli. Shigella flexneri. Pseudomonas aeruginosa. Salmonella typhi. Staphylococcus aureus and Bacillus subtilis) and for antifungal activity against six fungal strains (Trichophyton longifusus. Candida albicans. Aspergillus flavus. Microsporum canis. Fusarium solani and Candida glabrata). The in vitro antibacterial and antifungal bioactivity data showed the metal(II) complexes to be more potent than the parent ligands against one or more bacterial and fungal strains. PMID:23914928

  6. Synthesis, spectroscopic and thermal studies of the copper(II) aspartame chloride complex

    NASA Astrophysics Data System (ADS)

    Çakır, S.; Coşkun, E.; Naumov, P.; Biçer, E.; Bulut, İ.; İçbudak, H.; Çakır, O.

    2002-08-01

    Aspartame adduct of copper(II) chloride Cu(Asp) 2Cl 2·2H 2O (Asp=aspartame) is synthesized and characterized by elemental analysis, FT IR, UV/vis, ESR spectroscopies, TG, DTG, DTA measurements and molecular mechanics calculations. Aqueous solution of the green solid absorbs strongly at 774 and 367 nm. According to the FT IR spectra, the aspartame moiety coordinates to the copper(II) ion via its carboxylate ends, whereas the ammonium terminal groups give rise to hydrogen bonding network with the water, the chloride ions or neighboring carboxylate groups. The results suggest tetragonally distorted octahedral environment of the copper ions.

  7. A non-aggregated and tumour-associated macrophage-targeted photosensitiser for photodynamic therapy: a novel zinc(II) phthalocyanine containing octa-sulphonates.

    PubMed

    Li, Xing-Shu; Ke, Mei-Rong; Zhang, Miao-Fen; Tang, Qing-Qing; Zheng, Bi-Yuan; Huang, Jian-Dong

    2015-03-18

    A novel zinc(II) phthalocyanine bearing octa-sulphonates has been prepared, which is non-aggregated in water, highly photoactive and low dark-toxic. More interestingly, it exhibits specific affinity to macrophages via the scavenger receptor-A, and can selectively accumulate in tumour sites. PMID:25692672

  8. Copper(II) complexes with heterocyclic hydroxyimino-containing ligands

    SciTech Connect

    Kogan, V.A.; Burlov, A.S.; Popov, L.D.; Lukov, V.V.; Koshchienko, Yu.V.; Tsupak, E.B.; Barchan, G.P.; Chigarenko, G.G.; Bolotnikov, V.S.

    1988-05-01

    The reaction of oximes (R = Ph (L'), C=N (L'')) with the copper(II) salts CuA/sub 2/ in methanol has given the complexes CuL/sub 2/ ' x H/sub 2/O and CuL/sub 2//sup ''/ x 2H/sub 2/O (I) (A = Acet/sup -/), CuHLCl/sub 2/ x H/sub 2/O (II) (A = Cl/sup -/), CuLOH(ClO/sub 4/)/sub 2/ x 2H/sub 2/O (III) (A = ClO/sub 4//sup -/) and the complexes Cu/sub 3/L/sub 3//sup '/OH(NO/sub 3/)/sub 2/ and Cu/sub 3/L/sub 3//sup ''/(OH)/sub 2/NO/sub 3/ (IV) (A = NO/sub 3//sup -/). Their physicochemical properties have been studied by the methods of IR spectroscopy and magnetochemistry. It has been shown that complexes I have a chelate structure and that their magnetic moments are not dependent on the temperature. An anti-ferromagnetic exchange interaction takes place in complexes II-IV. On the basis of magnetochemical measurements over a broad temperature range and data calculated in the framework of the Heisenberg-Dirac-Van Vleck model of isotropic exchange interactions, a dimeric structure has been proposed for the complexes of type II, and a trinuclear cluster structure has been proposed for complexes III and IV.

  9. New Heteroleptic Copper(II) Complexes as MOCVD Precursors

    NASA Astrophysics Data System (ADS)

    Krisyuk, V. V.; Sysoev, S. V.; Rumyantsev, Y. M.; Prokhorova, S. A.; Maximovskiy, E. V.; Kosinova, M. L.; Igumenov, I. K.

    New volatile heteroleptic copper(II) complexes having beta-ketoiminate (O,N) and diketonate (O,O) ligands in one molecule were tested as precursors for LPCVD of copper films. Saturated vapor pressure was measured and compared for new compounds Cu(ki)(hfa) and Cu(dpk)(hfa), where ki = pentane-2-imino-4-onato, hfa = 1,1,1,5,5,5-hexafluoro-pentane- 2,4-dionato, dpk= 2,2,6,6-tetramethyl-3-iminoheptane-5-onato. The precursors are air stable and non hygroscopic compounds with long shelf life. It was demonstrated that copper metal films can be selectively deposited on metallic surfaces in the presence of hydrogen as a gas-reactant at temperatures of 250, 300, 350 °C and pressure of 20 Torr. Si(100), SiO2 (melted quartz), stainless steel, and Cu, Al, RuO2, Ru and Ta sublayers on Si(100) were tested as substrate materials. Deposited films were analyzed and characterized by X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and scanning electron microscopy (SEM).

  10. The antimicrobial and antibiofilm activities of copper(II) complexes.

    PubMed

    Beeton, Michael L; Aldrich-Wright, Janice R; Bolhuis, Albert

    2014-11-01

    Biofilm-related bacterial infections pose a significant problem, as they are generally more tolerant to antibiotics and the immune system. Development of novel compounds with antibiofilm activity is therefore paramount. In this study we have analysed metal complexes of the general structure [M(IL)(AL)](2+) (where IL represents functionalised 1,10-phenanthrolines and AL represents 1S,2S- or 1R,2R-diaminocyclohexane) and [Cu(IL)3](2+). Antimicrobial activity was tested on a number of bacterial strains, showing that copper(II) compounds were active against both Gram-positive and Gram-negative bacteria, albeit that activity was generally higher for the former. The antibiofilm activity was then determined against a clinical isolate of meticillin-resistant Staphylococcus aureus (MRSA). Strikingly, the copper complexes tested showed significant activity against biofilms, and were better in the removal of biofilms than vancomycin, an antibiotic that is currently used in the treatment of MRSA infections. PMID:25124857

  11. Tumour-localising and -photosensitising properties of a novel zinc(II) octadecylphthalocyanine.

    PubMed Central

    Ometto, C.; Fabris, C.; Milanesi, C.; Jori, G.; Cook, M. J.; Russell, D. A.

    1996-01-01

    1,4,8,11,15,18,22,25-Octadecylphthalocyaninato zinc(II), ZnODPc, incorporated into a Cremophor emulsion, was assayed for its pharmacokinetic and phototherapeutic properties in Balb/c mice bearing an intramuscularly transplanted MS-2 fibrosarcoma. The phthalocyanine was injected intravenously (i.v.) in three doses, i.e. 1.46, 0.73 and 0.37 mumol kg-1 body weight. In all cases, the octadecyl-substituted phthalocyanine showed an unusually high affinity for serum low-density lipoproteins (LDLs) and a high efficiency and selectivity of tumour targeting: the maximum accumulation in the tumour occurred at 24 h after injection, whereas no detectable amount of phthalocyanine was recovered from the muscle, i.e. the peritumoral tissue, between 1 h and 1 week after injection. At the same time, low amounts of phthalocyanine were recovered from skin and then only at short times after injection, with skin photosensitivity rapidly disappearing and the phthalocyanine present in the serum only. Tumour photosensitisation studies were carried out at 24 h after administration of 1.46 mumol kg-1 ZnODPc and showed that this phthalocyanine has a very high phototherapeutic efficiency; this is probably a consequence of the multiple mechanisms by which the phthalocyanine induces tumour damage, involving both direct modification of malignant cells and impairment of blood flow, as well as the alteration of a variety of subcellular components, such as mitochondria, the rough endoplasmic reticulum, the perinuclear membrane and, occasionally, cell nuclei. Tumour necrosis appears to be the consequence of both random cell death and apoptosis. Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 Figure 12 Figure 13 PMID:8980387

  12. Variation in the biomolecular interactions of nickel(II) hydrazone complexes upon tuning the hydrazide fragment.

    PubMed

    Krishnamoorthy, Paramasivam; Sathyadevi, Palanisamy; Butorac, Rachel R; Cowley, Alan H; Bhuvanesh, Nattamai S P; Dharmaraj, Nallasamy

    2012-06-14

    Three new bivalent nickel hydrazone complexes have been synthesised from the reactions of [NiCl(2)(PPh(3))(2)] with H(2)L {L = dianion of the hydrazones derived from the condensation of o-hydroxynaphthaldehyde with furoic acid hydrazide (H(2)L(1)) (1)/thiophene-2-acid hydrazide (H(2)L(2)) (2)/isonicotinic acid hydrazide (H(2)L(3)) (3)} and formulated as [Ni(L(1))(PPh(3))] (4), [Ni(L(2))(PPh(3))] (5) and [Ni(L(3))(PPh(3))] (6). Structural characterization of these compounds 4-6 were accomplished by using various physico-chemical techniques. Single crystal X-ray diffraction data of complexes 4 and 5 proved their distorted square planar geometry. In order to ascertain the potential of the above synthesised compounds towards biomolecular interactions, additional experiments involving interaction with calf thymus DNA (CT DNA) and bovine serum albumin (BSA) were carried out. All the ligands and corresponding nickel(ii) chelates have been screened for their scavenging effect towards O(2)(-), OH and NO radicals. The efficiency of complexes 4-6 to arrest the growth of HeLa, HepG-2 and A431 tumour cell lines has been studied along with the cell viability test against the non-cancerous NIH 3T3 cells under in vitro conditions. PMID:22506273

  13. Electrocatalytic Hydrogen Production by a Nickel(II) Complex with a Phosphinopyridyl Ligand.

    PubMed

    Tatematsu, Ryo; Inomata, Tomohiko; Ozawa, Tomohiro; Masuda, Hideki

    2016-04-18

    A novel nickel(II) complex [Ni(L)2 Cl]Cl with a bidentate phosphinopyridyl ligand 6-((diphenylphosphino)methyl)pyridin-2-amine (L) was synthesized as a metal-complex catalyst for hydrogen production from protons. The ligand can stabilize a low Ni oxidation state and has an amine base as a proton transfer site. The X-ray structure analysis revealed a distorted square-pyramidal Ni(II)  complex with two bidentate L ligands in a trans arrangement in the equatorial plane and a chloride anion at the apex. Electrochemical measurements with the Ni(II) complex in MeCN indicate a higher rate of hydrogen production under weak acid conditions using acetic acid as the proton source. The catalytic current increases with the stepwise addition of protons, and the turnover frequency is 8400 s(-1) in 0.1 m [NBu4 ][ClO4 ]/MeCN in the presence of acetic acid (290 equiv) at an overpotential of circa 590 mV. PMID:26991364

  14. Synthesis, structure and biological activity of nickel(II) complexes of 5-methyl 2-furfural thiosemicarbazone.

    PubMed

    Jouad, E M; Larcher, G; Allain, M; Riou, A; Bouet, G M; Khan, M A; Thanh, X D

    2001-09-01

    5-Methyl 2-furfuraldehyde thiosemicarbazone (M5HFTSC) with nickel(II) leads to three types of complexes: [Ni(M5HFTSC)(2)X(2)], [Ni(M5FTSC)(2)] and [Ni(M5FTSC)(2)] x 2DMF. In the first type the ligand remains in thione form, while in the two other, the anionic thiolato form is involved. The species [Ni(M5HFTSC)(2)X(2)] has been characterized spectroscopically. The structures of [Ni(M5FTSC)(2)] x 2DMF and [Ni(M5FTSC)(2)] have been solved using X-ray diffraction. Biological studies of [Ni(M5HFTSC)(2)Cl(2)] have been carried out in vitro for antifungal activity on human pathogenic fungi, Aspergillus fumigatus and Candida albicans, and in vivo for toxicity on mice. The results are compared to those of the ligand, the metal salt and a similar copper complex [Cu(M5HFTSC)Cl(2)]. PMID:11566328

  15. X-ray magnetic circular dichroism of Pseudomonas aeruginosa nickel(II) azurin.

    PubMed

    Funk, Tobias; Kennepohl, Pierre; Di Bilio, Angel J; Wehbi, William A; Young, Anthony T; Friedrich, Stephan; Arenholz, Elke; Gray, Harry B; Cramer, Stephen P

    2004-05-12

    We show that X-ray magnetic circular dichroism (XMCD) can be employed to probe the oxidation states and other electronic structural features of nickel active sites in proteins. As a calibration standard, we have measured XMCD and X-ray absorption (XAS) spectra for the nickel(II) derivative of Pseudomonas aeruginosa azurin (NiAz). Our analysis of these spectra confirms that the electronic ground state of NiAz is high-spin (S = 1); we also find that the L(3)-centroid energy is 853.1(1) eV, the branching ratio is 0.722(4), and the magnetic moment is 1.9(4) mu(B). Density functional theory (DFT) calculations on model NiAz structures establish that orbitals 3d(x2-y2) and 3d(z2) are the two valence holes in the high-spin Ni(II) ground state, and in accord with the experimentally determined orbital magnetic moment, the DFT results also demonstrate that both holes are highly delocalized, with 3d(x2-y2) having much greater ligand character. PMID:15125678

  16. Molecular Recognition and Scavenging of Arsenate from Aqueous Solution Using Dimetallic Receptors

    PubMed Central

    Moffat, Chris D; Weiss, Dominik J; Shivalingam, Arun; White, Andrew J P; Salaün, Pascal; Vilar, Ramon

    2014-01-01

    A series of copper(II), nickel(II) and zinc(II) dimetallic complexes were prepared and their affinities towards arsenate investigated. Indicator displacement assays (IDAs) were carried out to establish the complexes with best affinities towards arsenate. A di-zinc complex (3) was selected and its arsenate-binding abilities investigated by isothermal titration calorimetry (ITC). The X-ray crystal structure of this metallo-receptor bound to arsenate is also reported, which allowed us to establish the binding mode between 3 and this oxyanion. Immobilising 3 onto HypoGel resin yielded a novel adsorbent (Zn–HypoGel) with high affinity for arsenate. Adsorption of arsenate from competitive solutions and natural groundwater was greater than that of the commercially used iron oxide Bayoxide E33. Zn–HypoGel could be efficiently and simply regenerated by washing with sodium acetate solution. PMID:25338508

  17. Nickel(II) and palladium(II) thiaethyneporphyrins. Intramolecular metal(II)-η2-CC interaction inside a porphyrinoid frame.

    PubMed

    Nojman, Elżbieta; Berlicka, Anna; Szterenberg, Ludmiła; Latos-Grażyński, Lechosław

    2012-03-01

    3,18-Diphenyl-8,13-di-p-tolyl-20-thiaethyneporphyrin ([18]thiatriphyrin(4.1.1)), which formally contains an C1-C2 ethyne moiety instead of pyrrole embedded in the macrocyclic framework of 21-thiaporphyrin, was obtained in a modification of the "3 + 1" approach using the ethyne analogue of tripyrrane (1,4-diphenyl-1,4-di(pyrrol-2-yl)but-2-yne) and 2,5-bis(p-tolylhydroxymethyl)thiophene. The spectroscopic and structural properties of 20-thiaethyneporphyrin reflect its macrocyclic aromaticity, revealing a combination of the acetylene (≥C-C≡C-C≤) and cumulene (>C═C═C═C<) character of the C18-C1-C2-C3 linker. The magnetic manifestations of aromaticity and antiaromaticity of thiaethyneporphyrin and its two-electron-oxidized derivative were observed using (1)H NMR spectroscopy and were confirmed by density functional theory calculations involving chemical shifts and nucleus-independent chemical shift analysis. Protonation of 20-thiaethyneporphyrin yielded a nonaromatic tautomer of iso-20-thiaethyneporphyrin, locating the saturated meso carbon adjacent to thiophene. Insertion of palladium(II) and nickel(II) into 20-thiaethyneporphyrin afforded planar palladium(II) thiaethyneporphyrin and low-spin diamagnetic nickel(II) 20-thiaethyneporphyrin as determined by X-ray crystallography. 20-Thiaethyneporphyrin acts as a dianionic ligand that coordinates through the two nitrogen and one sulfur donors. Metal(II) ions are uniquely exposed to form an intramolecular metal(II)-η(2)-CC bond, whereas the organometallic fragment is coplanar with the whole macrocycle. Coordination of pyridine converts diamagnetic nickel(II) thiaethyneporphyrin into its paramagnetic counterpart as determined by (1)H NMR. PMID:22356285

  18. Phosphate effects on copper(II) and lead(II) sorption to ferrihydrite

    NASA Astrophysics Data System (ADS)

    Tiberg, Charlotta; Sjöstedt, Carin; Persson, Ingmar; Gustafsson, Jon Petter

    2013-11-01

    Transport of lead(II) and copper(II) ions in soil is affected by the soil phosphorus status. Part of the explanation may be that phosphate increases the adsorption of copper(II) and lead(II) to iron (hydr)oxides in soil, but the details of these interactions are poorly known. Knowledge about such mechanisms is important, for example, in risk assessments of contaminated sites and development of remediation methods. We used a combination of batch experiments, extended X-ray absorption fine structure (EXAFS) spectroscopy and surface complexation modeling with the three-plane CD-MUSIC model to study the effect of phosphate on sorption of copper(II) and lead(II) to ferrihydrite. The aim was to identify the surface complexes formed and to derive constants for the surface complexation reactions. In the batch experiments phosphate greatly enhanced the adsorption of copper(II) and lead(II) to ferrihydrite at pH < 6. The largest effects were seen for lead(II).

  19. The amyloid precursor protein of Alzheimer's disease in the reduction of copper(II) to copper(I)

    PubMed

    Multhaup, G; Schlicksupp, A; Hesse, L; Beher, D; Ruppert, T; Masters, C L; Beyreuther, K

    1996-03-01

    The transition metal ion copper(II) has a critical role in chronic neurologic diseases. The amyloid precursor protein (APP) of Alzheimer's disease or a synthetic peptide representing its copper-binding site reduced bound copper(II) to copper(I). This copper ion-mediated redox reaction led to disulfide bond formation in APP, which indicated that free sulfhydryl groups of APP were involved. Neither superoxide nor hydrogen peroxide had an effect on the kinetics of copper(II) reduction. The reduction of copper(II) to copper(I) by APP involves an electron-transfer reaction and could enhance the production of hydroxyl radicals, which could then attack nearby sites. Thus, copper-mediated toxicity may contribute to neurodegeneration in Alzheimer's disease. PMID:8596911

  20. Transition metal complexes of neocryptolepine analogues. Part I: Synthesis, spectroscopic characterization, and invitro anticancer activity of copper(II) complexes

    NASA Astrophysics Data System (ADS)

    Emam, Sanaa Moustafa; El Sayed, Ibrahim El Tantawy; Nassar, Nagla

    2015-03-01

    New generation of copper(II) complexes with aminoalkylaminoneocryptolepine as bidentate ligands has been synthesized and it is characterized by elemental analyses, magnetic moment, spectra (IR, UV-Vis, 1H NMR and ESR) and thermal studies. The IR data suggest the coordination modes for ligands which behave as a bidentate with copper(II) ion. Based on the elemental analysis, magnetic studies, electronic and ESR data, binuclear square planar geometry was proposed for complexes 7a, 7b, square pyramidal for 9a, 9b and octahedral for 8a, 8b, 10a, 10b. The molar conductance in DMF solution indicates that all complexes are electrolyte except 7a and 7b. The ESR spectra of solid copper(II) complexes in powder form showed an axial symmetry with 2B1g as a ground state and hyperfine structure. The thermal stability and degradation of the ligands and their metal complexes were studied employing DTA and TG methods. The metal-free ligands and their copper(II) complexes were tested for their in vitro anticancer activity against human colon carcinoma (HT-29). The results showed that the synthesized copper(II) complexes exhibited higher anticancer activity than their free ligands. Of all the studied copper(II) complexes, the bromo-substituted complex 9b exhibited high anticancer activity at low micromolar inhibitory concentrations (IC50 = 0.58 μM), compared to the other complexes and the free ligands.

  1. Geometric and Electronic Structures of Nickel(II) Complexes of Redox Noninnocent Tetradentate Phenylenediamine Ligands.

    PubMed

    Ciccione, Jérémie; Leconte, Nicolas; Luneau, Dominique; Philouze, Christian; Thomas, Fabrice

    2016-01-19

    Five tetradentate ligands based on the N,N'-bis(2-amino-3,5-di-tert-butylphenyl)-o-phenylenediamine backbone were prepared, with different substituents at positions 4 and 5 (CH3 (3a), p-CH3O-C6H4 (3b), H (3c), Cl (3d), F (3e)). Their reaction with a nickel(II) salt in air affords the neutral species 4(a-e), which were isolated as single crystals. 4(a-e) feature two antiferromagnetically exchange-coupled diiminosemiquinonate moieties, both located on peripheral rings, and a diamidobenzene bridging unit. Oxidation of 4(a-e) with 1 equiv of AgSbF6 yields the cations 4(a-e)(+), which harbor a single diiminosemiquinonate radical. Significant structural differences were observed within the series. 4b(+) is mononuclear and contains a localized diiminosemiquinonate moiety. In contrast, 4c(+) is a dimer wherein the diiminosemiquinonate radical is rather delocalized over both peripheral rings. 4d(+) represents an intermediate case where the complex is mononuclear, but the radical is fully delocalized. Oxidation of 4(a-e) with 2 equiv of AgSbF6 produces the corresponding mononuclear dications. X-ray diffraction data on 4(b-d)(2+) reveals that the bridging ring retains its diamidobenzene character, whereas both peripheral rings have been oxidized into diiminobenzoquinone moieties. All the complexes were characterized by electrochemistry, EPR, and UV-vis-NIR spectroscopy. Remarkably, the electronic structures of the complexes differ from those reported by Wieghardt et al. for copper and zinc complexes of a related ligand involving a mixed N2O2 donor set (J. Am. Chem. Soc. 1999, 121, 9599). The easier oxidation of phenylenediamine moieties in comparison to aminophenols is proposed to account for the difference. PMID:26689346

  2. Nickel(ii) radical complexes of thiosemicarbazone ligands appended by salicylidene, aminophenol and aminothiophenol moieties.

    PubMed

    Kochem, Amélie; Gellon, Gisèle; Jarjayes, Olivier; Philouze, Christian; du Moulinet d'Hardemare, Amaury; van Gastel, Maurice; Thomas, Fabrice

    2015-07-28

    The nickel(ii) complexes of three unsymmetrical thiosemicarbazone-based ligands featuring a sterically hindered salicylidene (1), aminophenol (2) or thiophenol (3) moiety were synthesized and structurally characterized. The metal ion lies in an almost square planar geometry in all the complexes. The cyclic voltammetry (CV) curve of 1 shows an irreversible oxidation wave at E = 0.49 V, which is assigned to the phenoxyl/phenolate redox couple. The CV curves of 2 and 3 display a reversible one-electron oxidation wave (E1/2 = 0.26 and 0.22 V vs. Fc(+)/Fc, respectively) and an one-electron reduction wave (E1/2 = -1.55 and -1.46 V, respectively). The cations 2(+) and 3(+) as well as the anions 2(-) and 3(-) were generated. The EPR spectra of the cations in THF show a rhombic signal at g1 = 2.034, g2 = 2.010 and g3 = 1.992 (2(+)) and g1 = 2.069, g2 = 2.018, g3 = 1.986 (3(+)) that is consistent with a main radical character of the complexes. The difference in anisotropy is assigned to the different nature of the radical, iminosemiquinonate vs. iminothiosemiquinonate. The anions display an isotropic EPR signal at giso = 2.003 (2(+)) and 2.006 (3(+)), which is indicative of a main α-diimine radical character of the compounds. Both the anions and cations exhibit charge transfer transitions of low to moderate intensity in their visible spectrum. Quantum chemical calculations (B3LYP) reproduce both the g-values and Vis-NIR spectra of the complexes. The radical anions readily react with dioxygen to give the radical cations. 2(+) catalyzes the aerobic oxidation of benzyl alcohol into benzaldehyde. PMID:26086684

  3. The X-ray structures, vibrational spectroscopy and antimicrobial activity of nickel(II) complexes with 4-hydroxybenzhydrazide

    NASA Astrophysics Data System (ADS)

    Zasłona, Halina; Drożdżewski, Piotr; Ślepokura, Katarzyna

    2015-11-01

    Two novel nickel(II) complexes, [Ni(4hbah)3]SO4•CH3OH•5H2O (I) and [Ni(4hbah)3](SO4)·6H2O (II), have been synthesized and characterized by single-crystal X-ray crystallography. The nickel(II) coordinates three 4-hydroxybenzhydrazide (4hbah) ligands with the donor oxygen and nitrogen atoms arranged in fac configuration. Both compounds spontaneously decompose on air losing some water molecules and forming [Ni(4hbah)3]SO4•CH3OH•2H2O (Ia) and [Ni(4hbah)3]SO4•2H2O (IIa), respectively. The Ia and IIa were used for measurement of IR and Raman spectra, which have been interpreted with help of DFT calculations and special experimental techniques, such as O,N-deuteration and 58Ni/64Ni isotope substitution. The combination of these experimental and theoretical attempts allowed us to make reliable assignment of the observed bands, including the strongly coupled nickel(II)-ligand vibrations. The Ia complex shows better antibacterial activity than the 4hbah ligand.

  4. Characterization and metal sorptive properties of oxidized active carbon.

    PubMed

    Strelko, Vladimir; Malik, Danish J

    2002-06-01

    A commercial activated carbon Chemviron F 400 has been oxidized using nitric acid in order to introduce a variety of acidic surface functional groups. Both unoxidized and oxidized carbon samples were characterized using nitrogen porosimetry, elemental analysis, pH titration, Boehm's titration, and electrophoretic mobility measurements. Results show that oxidation treatment reduced surface area and pore volume. However, the carbon surface acquires an acidic character with carboxylic groups being the dominant surface functional groups. The modified sample displays cation-exchange properties over a wide range of pH values and exhibits polyfunctional nature. Both carbon samples were challenged for the removal of transition metals such as copper(II), nickel(II), cobalt(II), zinc(II), and manganese(II). The affinity series Mn2+Zn2+ has been found to coincide with the general stability sequence of metal complexes (the Irving-Williams series). The higher preference displayed by carbons toward copper(II) is a consequence of the fact that copper(II) often forms distorted and more stable octahedral complexes. PMID:16290653

  5. Synthesis, structural and optical properties of 1-alkyl-2-(2'-tosylaminophenyl)-5-nitrobenzimidazoles and their zinc(II) complexes

    NASA Astrophysics Data System (ADS)

    Burlov, Anatolii S.; Koshchienko, Yurii V.; Kiskin, Mikhail A.; Nikolaevskii, Stanislav A.; Garnovskii, Dmitrii A.; Lermontov, Anatolii S.; Makarova, Nadegda I.; Metelitsa, Anatolii V.; Eremenko, Igor L.

    2016-01-01

    A series of novel benzimidazole derivatives 1-alkyl-2-(2'-tosylaminophenyl)-5-nitrobenzimidazoles with common formulas HL (1-3) (R = C2H5 (1); R = n-C3H7 (2); R = n-C4H9(3)) and their mononuclear zinc(II) complexes ZnL2 (4-6) have been synthesized in a molar ratio Zn: HL = 1:2 in methanol solutions. Formulation of 1-6 is based upon satisfactory C, H, N, S elemental analyses, IR and 1H, 13C NMR spectroscopies, while the structures of 2, 3, 5, 6 were determined by X-ray single-crystal diffraction. The optical properties of 1-6 were investigated.

  6. Mononuclear zinc(II) complexes of 2-((2-(piperazin-1-yl)ethylimino)methyl)-4-substituted phenols: Synthesis, structural characterization, DNA binding and cheminuclease activities

    NASA Astrophysics Data System (ADS)

    Ravichandran, J.; Gurumoorthy, P.; Karthick, C.; Kalilur Rahiman, A.

    2014-03-01

    Four new zinc(II) complexes [Zn(HL1-4)Cl2] (1-4), where HL1-4 = 2-((2-(piperazin-1-yl)ethylimino)methyl)-4-substituted phenols, have been isolated and fully characterized using various spectro-analytical techniques. The X-ray crystal structure of complex 4 shows the distorted trigonal-bipyramidal coordination geometry around zinc(II) ion. The crystal packing is stabilized by intermolecular NH⋯O hydrogen bonding interaction. The complexes display no d-d electronic band in the visible region due to d10 electronic configuration of zinc(II) ion. The electrochemical properties of the synthesized ligands and their complexes exhibit similar voltammogram at reduction potential due to electrochemically innocent Zn(II) ion, which evidenced that the electron transfer is due to the nature of the ligand. Binding interaction of complexes with calf thymus DNA was studied by UV-Vis absorption titration, viscometric titration and cyclic voltammetry. All complexes bind with CT DNA by intercalation, giving the binding affinity in the order of 2 > 1 ≫ 3 > 4. The prominent cheminuclease activity of complexes on plasmid DNA (pBR322 DNA) was observed in the absence and presence of H2O2. Oxidative pathway reveals that the underlying mechanism involves hydroxyl radical.

  7. Synthesis and characterization of different zinc(II) oxide nano-structures from two new zinc(II)-Quinoxaline coordination polymers

    NASA Astrophysics Data System (ADS)

    Molaei, Fatemeh; Bigdeli, Fahime; Morsali, Ali; Joo, Sang Woo; Bruno, Giuseppe; Rudbari, Hadi Amiri

    2015-09-01

    Two new zinc(II) coordination polymers, [Zn(Quinoxaline)(NO3)2(H2O)2]nṡQuinoxaline·H2O (1) and [Zn(Quinoxaline)2(Br)2]n (2), Quinoxaline = Benzopyrazine, have been synthesized and characterized by IR spectroscopy. Compounds 1 and 2 were structurally characterized by single crystal X-ray diffraction and are one-dimensional coordination polymers with coordination environment of octahedral and tetrahedral respectively. Nanostructures of zinc(II) oxide were obtained by thermolyses of compound 1 in oleic acid, calcination of compound 1 at 500 °C under air atmosphere and sol-gel processes. Also, nanopowders of zinc(II) oxide were obtained by calcination of compound 2 at 450 and 550 °C. The nanomaterials were characterized by scanning electron microscopy and X-ray powder diffraction (XRD). The thermal stability of compounds 1 and 2 both their bulk were studied by thermo-gravimetric (TGA) and differential thermal analyses (DTA). This study demonstrates the coordination polymers may be suitable precursors for the preparation of nanoscale materials.

  8. Antifouling bastadin congeners target mussel phenoloxidase and complex copper(II) ions.

    PubMed

    Bayer, Mirko; Hellio, Claire; Maréchal, Jean-Philippe; Frank, Walter; Lin, Wenhan; Weber, Horst; Proksch, Peter

    2011-12-01

    Synthetically prepared congeners of sponge-derived bastadin derivatives such as 5,5'-dibromohemibastadin-1 (DBHB) that suppress the settling of barnacle larvae were identified in this study as strong inhibitors of blue mussel phenoloxidase that is involved in the firm attachment of mussels to a given substrate. The IC₅₀ value of DBHB as the most active enzyme inhibitor encountered in this study amounts to 0.84 μM. Inhibition of phenoloxidase by DBHB is likely due to complexation of copper(II) ions from the catalytic centre of the enzyme by the α-oxo-oxime moiety of the compound as shown here for the first time by structure activity studies and by X-ray structure determination of a copper(II) complex of DBHB. PMID:21547349

  9. A new dioxime ligand and its trinuclear copper(II) complex: Synthesis, characterization and optical properties

    NASA Astrophysics Data System (ADS)

    Karipcin, Fatma; Dede, Bülent; Caglar, Yasemin; Hür, Deniz; Ilican, Saliha; Caglar, Mujdat; Şahin, Yücel

    2007-04-01

    The synthesis and characterization of a new dioxime ligand, (H2L), (III) and its trinuclear copper(II) complex, [Cu3L2(H2O)2](ClO4)2, (V) is described. IR spectra show that the ligand acts in a tetradentate manner and coordinates N4 donor groups of H2L to copper(II) ion. The structure of the metal chelate is clarified with the help of elemental analysis, magnetic moment, conductometric and spectroscopic measurements. The optical absorption studies reveal that the transition is direct with band gap energy values are calculated. The optical constants such as refractive index and dielectric constant of the compound were determined. The refractive index dispersion curves of the films obey the single-oscillator model and oscillator parameters. Optical dispersion parameters E0 and Ed developed by Wemple-DiDomenico were calculated.

  10. Infrared spectroscopic study of copper(II) complexes with N-substituted tetrazoles1

    NASA Astrophysics Data System (ADS)

    Degtyarik, M. M.; Gaponik, P. N.; Naumenko, V. N.; Lesnikovich, A. I.; Nikanovich, M. V.

    The i.r. spectra (4000-200 cm -1) of N-alkyltetrazoles and their complexes with copper(II) salts CuCl 2 and Cu(NCS) 2 have been measured. Spectral criteria in the middle and far regions for the identification of tetrazole isomers and their complexes are proposed. The site of the coordination in a tetrazole molecule and supposed structure of complexes are being discussed.

  11. Thermochromism in nickel(II) complexes: thermal, solid state 1H NMR and single crystal X-ray analysis of bis-( N, N-dimethyl-1,2-ethanediamine) nickel(II) perchlorate

    NASA Astrophysics Data System (ADS)

    Koner, Subratanath; Tsutake, Masaru; Nagasawa, Isoroku; Ikeda, Ryuichi; Saha, Pratap K.; Mukherjee, Alok K.; Banerjee, Surajit

    2002-08-01

    The complex bis-( N, N-dimethyl-1,2-ethanediamine) nickel(II) perchlorate undergoes a first-order thermochromic phase transition at ca. 476 K, changing its color from orange to red. The room temperature X-ray crystal structure determination showed that the nickel ion possesses a square-planar geometry with two five membered chelate rings, in the δλ conformation, forming the NiN 4 chromophore. The broad-line 1H NMR indicates the onset of a dynamic disorder of diamine chelate rings at the phase transition temperature region, while T1 measurement of 1H affords the activation energy of the puckering metal chelate rings to be 26 kJ mol -1. The electronic spectrum revealed that a weakening of ligand field around the nickel is associated with the phase transition.

  12. Redox Activity of Copper(II) Complexes with NSFRY Pentapeptide and Its Analogues

    PubMed Central

    Wiloch, Magdalena Zofia; Wawrzyniak, Urszula Elżbieta; Ufnalska, Iwona; Piotrowski, Grzegorz; Bonna, Arkadiusz; Wróblewski, Wojciech

    2016-01-01

    The influence of cation-π interactions on the electrochemical properties of copper(II) complexes with synthesized pentapeptide C-terminal fragment of Atrial Natriuretic Factor (ANF) hormone was studied in this work. Molecular modeling performed for Cu(II)-NSFRY-NH2 complex indicated that the cation-π interactions between Tyr and Cu(II), and also between Phe-Arg led to specific conformation defined as peptide box, in which the metal cation is isolated from the solvent by peptide ligand. Voltammetry experiments enabled to compare the redox properties and stability of copper(II) complexes with NSFRY-NH2 and its analogues (namely: NSFRA-NH2, NSFRF-NH2, NSAAY-NH2, NSAAA-NH2, AAAAA-NH2) as well as to evaluate the contribution of individual amino acid residues to these properties. The obtained results led to the conclusion, that cation-π interactions play a crucial role in the effective stabilization of copper(II) complexes with the fragments of ANF peptide hormone and therefore could control the redox processes in other metalloproteins. PMID:27517864

  13. An unusual 3D interdigitated architecture assembled from Keggin polyoxometalates and dinuclear copper(II) complexes

    SciTech Connect

    Pang, Haijun; Yang, Ming; Kang, Lu; Ma, Huiyuan; Liu, Bo; Li, Shaobin; Liu, Heng

    2013-02-15

    A novel organic-inorganic hybrid compound, [Cu{sub 2}(bipy){sub 3}({mu}{sub 1}-H{sub 2}O){sub 2}({mu}{sub 2}-H{sub 2}O)({mu}{sub 2}-OH)(H{sub 2}BW{sub 12}O{sub 40})]{center_dot}4 H{sub 2}O (1) (bipy=4,4 Prime -bipy), has been synthesized in hydrothermal condition and characterized by elemental analysis, IR spectrum, TG analysis and single-crystal X-ray diffraction. Compound 1 possesses poly-pendant layered motifs composed of 12-tungstoborates and dinuclear copper(II) complexes, in which the mono-coordinated bipy molecules are orderly appended to both sides of the layer, respectively. Adjacent layers mutually engage in a zipper-like pattern to result in a novel 3D interdigitated architecture. The variable-temperature magnetic susceptibility of 1 showed that there existed weak antiferromagnetic interaction in 1. Toward the reduction of hydrogen peroxide, 1 has good electrocatalytic activity and remarkable stability. - A new compound has been obtained, which represents the first interdigitated architecture assembled by POMs and dinuclear copper(II) complexes. Highlights: Black-Right-Pointing-Pointer The first example of interdigitated architecture assembled by POMs and dinuclear copper(II) complexes is observed. Black-Right-Pointing-Pointer A zipper-like pattern is observed in the structure. Black-Right-Pointing-Pointer The IR, TG, XRPD, magnetism and electrochemical property of the title compound were studied.

  14. Synthesis, crystal structure and investigation of mononuclear copper(II) and zinc(II) complexes of a new carboxylate rich tripodal ligand and their interaction with carbohydrates in alkaline aqueous solution

    PubMed Central

    Stewart, Christopher D.; Pedraza, Mayra; Arman, Hadi; Fan, Hua-Jun; Schilling, Eduardo Luiz; Szpoganicz, Bruno; Musie, Ghezai T.

    2016-01-01

    A new carboxylate rich asymmetric tripodal ligand, N-[2-carboxybenzomethyl]-N-[carboxymethyl]-β-alanine (H3camb), and its di-copper(II), (NH4)2[1]2, and di-zinc(II), ((CH3)4 N)2[2]2, complexes have been synthesized as carbohydrate binding models in aqueous solutions. The ligand and complexes have been fully characterized using several techniques, including single crystal X-ray diffraction. The interactions of (NH4)2[1]2 and ((CH3)4 N)2[2]2 with D-glucose, D-mannose, D-xylose and xylitol in aqueous alkaline media were investigated using UV–Vis and 13C-NMR spectroscopic techniques, respectively. The molar conductance, NMR and ESI–MS studies indicate that the complexes dissociate in solution to produce the respective complex anions, 1− and 2−. Complexes 1− and 2− showed chelating ability towards the naturally abundant and biologically relevant sugars, D-glucose, D-mannose, D-xylose, and xylitol. The complex ions bind to one molar equivalent of the sugars, even in the presence of stoichiometric excess of the substrates, in solution. Experimentally obtained spectroscopic data and computational results suggest that the substrates bind to the metal center in a bidentate fashion. Apparent binding constant values, pKapp, between the complexes and the substrates were determined and a specific mode of substrate binding is proposed. The pKapp and relativistic density functional theory (DFT) calculated Gibbs free energy values indicate that D-mannose displayed the strongest interaction with the complexes. Syntheses, characterizations, detailed substrate binding studies using spectroscopic techniques, single crystal X-ray diffraction and geometry optimizations of the complex-substrates with DFT calculations are also reported. PMID:25969174

  15. Synthesis, crystal structure and investigation of mononuclear copper(II) and zinc(II) complexes of a new carboxylate rich tripodal ligand and their interaction with carbohydrates in alkaline aqueous solution.

    PubMed

    Stewart, Christopher D; Pedraza, Mayra; Arman, Hadi; Fan, Hua-Jun; Schilling, Eduardo Luiz; Szpoganicz, Bruno; Musie, Ghezai T

    2015-08-01

    A new carboxylate rich asymmetric tripodal ligand, N-[2-carboxybenzomethyl]-N-[carboxymethyl]-β-alanine (H3camb), and its di-copper(II), (NH4)2[1]2, and di-zinc(II), ((CH3)4N)2[2]2, complexes have been synthesized as carbohydrate binding models in aqueous solutions. The ligand and complexes have been fully characterized using several techniques, including single crystal X-ray diffraction. The interactions of (NH4)2[1]2 and ((CH3)4N)2[2]2 with D-glucose, D-mannose, D-xylose and xylitol in aqueous alkaline media were investigated using UV-Vis and (13)C-NMR spectroscopic techniques, respectively. The molar conductance, NMR and ESI-MS studies indicate that the complexes dissociate in solution to produce the respective complex anions, 1(-) and 2(-). Complexes 1(-) and 2(-) showed chelating ability towards the naturally abundant and biologically relevant sugars, D-glucose, D-mannose, D-xylose, and xylitol. The complex ions bind to one molar equivalent of the sugars, even in the presence of stoichiometric excess of the substrates, in solution. Experimentally obtained spectroscopic data and computational results suggest that the substrates bind to the metal center in a bidentate fashion. Apparent binding constant values, pK(app), between the complexes and the substrates were determined and a specific mode of substrate binding is proposed. The pK(app) and relativistic density functional theory (DFT) calculated Gibbs free energy values indicate that D-mannose displayed the strongest interaction with the complexes. Syntheses, characterizations, detailed substrate binding studies using spectroscopic techniques, single crystal X-ray diffraction and geometry optimizations of the complex-substrates with DFT calculations are also reported. PMID:25969174

  16. Novel Cage-Like Hexanuclear Nickel(II) Silsesquioxane. Synthesis, Structure, and Catalytic Activity in Oxidations with Peroxides.

    PubMed

    Bilyachenko, Alexey N; Yalymov, Alexey I; Shul'pina, Lidia S; Mandelli, Dalmo; Korlyukov, Alexander A; Vologzhanina, Anna V; Es'kova, Marina A; Shubina, Elena S; Levitsky, Mikhail M; Shul'pin, Georgiy B

    2016-01-01

    New hexanuclear nickel(II) silsesquioxane [(PhSiO1.5)12(NiO)₆(NaCl)] (1) was synthesized as its dioxane-benzonitrile-water complex (PhSiO1,5)12(NiO)₆(NaCl)(C₄H₈O₂)13(PhCN)₂(H₂O)₂ and studied by X-ray and topological analysis. The compound exhibits cylinder-like type of molecular architecture and represents very rare case of polyhedral complexation of metallasilsesquioxane with benzonitrile. Complex 1 exhibited catalytic activity in activation of such small molecules as light alkanes and alcohols. Namely, oxidation of alcohols with tert-butylhydroperoxide and alkanes with meta-chloroperoxybenzoic acid. The oxidation of methylcyclohexane gave rise to the isomeric ketones and unusual distribution of alcohol isomers. PMID:27213319

  17. Synthesis and X-ray diffraction study of some nickel(II) complexes of urea and thiourea

    NASA Astrophysics Data System (ADS)

    Sharma, Pradeep; Bhale, Jaishree; Mishra, Ashutosh; Malviya, Pramod

    2014-09-01

    XRD of four biologically important nickel(II) complexes having urea and thiourea as primary ligands and sulphate and nitrate as secondary ligands have been studied using Bruker D8 Advance diffractometer at IUC, Indore. The synthesized metal complexes were characterized by XRD measurements in order to elucidate their geometry. The data obtained has been preceded using XRD data analysis program Origin 6.0 Professional. From the experimental measurements, various parameters, e.g., particle size, lattice parameter have been estimated.Particle size for Ni-urea complexes is found in the range of 4.23-9.01 nm while for Ni-thiourea complexes its range is 0.26-9.76 nm.Lattice parameter for all these complexes is found in the range of 7.47-8.06 Å. The XRD analysis revealed the crystalline nature of all the complexes.

  18. Combining NMR of dynamic and paramagnetic molecules: fluxional high-spin nickel(II) complexes bearing bisguanidine ligands.

    PubMed

    Roquette, Pascal; Maronna, Astrid; Reinmuth, Matthias; Kaifer, Elisabeth; Enders, Markus; Himmel, Hans-Jörg

    2011-03-01

    A detailed nuclear magnetic resonance (NMR) study was carried out on a series of paramagnetic, tetrahedrally coordinated nickel(II) dihalide complexes featuring chelating guanidine ligands. A complete assignment of the NMR signals for all complexes was achieved by sophisticated NMR experiments, including correlation spectra. The effects of halide exchange, as well as the variation in the guanidine-metal bite angles on the paramagnetic shifts, were assessed. The paramagnetic shift was derived with the aid of the diamagnetic NMR spectra of the analogous Zn complexes, which were synthesized for this purpose. The experimentally derived paramagnetic shift was then compared with the values obtained from quantum chemical (DFT) calculations. Furthermore, variable-temperature NMR studies were recorded for all complexes. It is demonstrated that NMR spectroscopy can be applied to evaluate the rate constants of fast fluxional processes within paramagnetic and catalytically active metal complexes. PMID:21268654

  19. Ultraviolet spectrophotometric characterization of copper(II) complexes with imidazole N-methyl derivatives of ?-histidine in aqueous solution

    NASA Astrophysics Data System (ADS)

    Prenesti, Enrico; Berto, Silvia; Daniele, Pier Giuseppe

    2003-01-01

    In this study we considered π-methyl- L-histidine (π-methis) and τ-methyl- L-histidine (τ-methis) as ligands for copper(II) ion, in order to clarify, by means of ultraviolet (UV) spectroscopy in aqueous solution ( T=25 °C, I=0.1 M), some aspects of the co-ordination mode with respect to other ligands of a previous study in which copper(II) complexes of L-histidine, N-acetyl- L-histidine, histamine, L-histidine methyl ester or carnosine were investigated. Particularly, UV spectra (300-400 nm) were recorded on solutions at various pH values, containing each binary system Cu-L; afterwards, an UV absorption spectrum for single complexes was calculated, taking into account the chemical model previously assessed, in order to fulfil a correct spectrum-structure correlation. The problem related to the eventual superimposition of the CT shoulder (≈330 nm) to copper(II) of OH - and imidazole pyridine nitrogen groups were now solved by means of a comparison of the UV spectra of dimer species formed by both π-methis or τ-methis. Finally, copper(II) complex formation with 2,2'-bipyridine was taken into account to compare the behaviour of pyridine (from 2,2'-bipyridine) and pyridine imidazole nitrogens (from π-methis or τ-methis) with respect to the UV charge transfer process to copper(II) ion.

  20. A new zinc(II) fluorophore 2-(9-anthrylmethylamino)ethyl-appended 1,4,7,10-tetraazacyclododecane.

    PubMed

    Aoki, Shin; Kaido, Saori; Fujioka, Haruto; Kimura, Eiichi

    2003-02-24

    A new 2-(9-anthrylmethylamino)ethyl-appended cyclen, L(3) (1-(2-(9-anthrylmethylamino)ethyl)-1,4,7,10-tetraazacyclododecane) (cyclen = 1,4,7,10-tetraazacyclododecane), was synthesized and characterized for a new Zn(2+) chelation-enhanced fluorophore, in comparison with previously reported 9-anthrylmethylcyclen L(1) (1-(9-anthrylmethyl)-1,4,7,10-tetraazacyclododecane) and dansylamide cyclen L(2). L(3) showed protonation constants log K(a)(i)() of 10.57 +/- 0.02, 9.10 +/- 0.02, 7.15 +/- 0.02, <2, and <2. The log K(a3) value of 7.15 was assigned to the pendant 2-(9-anthrylmethylamino)ethyl on the basis of the pH-dependent (1)H NMR and fluorescence spectroscopic measurements. The potentiometric pH titration study indicated extremely stable 1:1 Zn(2+)-L(3) complexation with a stability constant log K(s)(ZnL(3)) (where K(s)(ZnL(3)) = [ZnL(3)]/[Zn(2+)][L(3)] (M(-)(1))) of 17.6 at 25 degrees C with I = 0.1 (NaNO(3)), which is translated into the much smaller apparent dissociation constant K(d) (=[Zn(2+)](free)[L(3)](free)/[ZnL(3)]) of 2 x 10(-)(11) M with respect to 5 x 10(-)(8) M for L(1) at pH 7.4. The quantum yield (Phi = 0.14) in the fluorescent emission of L(3) increased to Phi = 0.44 upon complexation with zinc(II) ion at pH 7.4 (excitation at 368 nm). The fluorescence of 5 microM L(3) at pH 7.4 linearly increased with a 0.1-5 microM concentration of zinc(II). By comparison, the fluorescent emission of the free ligand L(1) decreased upon binding to Zn(2+) (from Phi = 0.27 to Phi = 0.19) at pH 7.4 (excitation at 368 nm). The Zn(2+) complexation with L(3) occurred more rapidly (the second-order rate constant k(2) is 4.6 x 10(2) M(-)(1) s(-)(1)) at pH 7.4 than that with L(1) (k(2) = 5.6 x 10 M(-)(1) s(-)(1)) and L(2) (k(2) = 1.4 x 10(2) M(-)(1) s(-)(1)). With an additionally inserted ethylamine in the pendant group, the macrocyclic ligand L(3) is a more effective and practical zinc(II) fluorophore than L(1). PMID:12588134

  1. Cobalt(II), Nickel(II) and Copper(II) complexes of a tetradentate Schiff base as photosensitizers: Quantum yield of 1O2 generation and its promising role in anti-tumor activity

    NASA Astrophysics Data System (ADS)

    Pradeepa, S. M.; Bhojya Naik, H. S.; Vinay Kumar, B.; Indira Priyadarsini, K.; Barik, Atanu; Ravikumar Naik, T. R.

    2013-01-01

    In the present investigation, a Schiff base N'1,N'3-bis[(E)-(5-bromo-2-hydroxyphenyl)methylidene]benzene-1,3-dicarbohydrazide and its metal complexes have been synthesized and characterized. The DNA-binding studies were performed using absorption spectroscopy, emission spectra, viscosity measurements and thermal denatuaration studies. The experimental evidence indicated that, the Co(II), Ni(II) and Cu(II) complexes interact with calf thymus DNA through intercalation with an intrinsic binding constant Kb of 2.6 × 104 M-1, 5.7 × 104 M-1 and 4.5 × 104 M-1, respectively and they exhibited potent photodamage abilities on pUC19 DNA, through singlet oxygen generation with quantum yields of 0.32, 0.27 and 0.30 respectively. The cytotoxic activity of the complexes resulted that they act as a potent photosensitizers for photochemical reactions.

  2. Synthesis and Characterization of Cobalt(III), Nickel(II) and Copper(II) Mononuclear Complexes with the Ligand 1,3-bis[(2-aminoethyl)amino]-2-propanol and Their Catalase-Like Activity

    PubMed Central

    Silva, Daniel M.; Visentin, Lorenzo C.; Rodrigues, Bernardo L.

    2015-01-01

    In this work, we present the synthesis and characterization of two new mononuclear complexes with the ligand 1,3-bis[(2-aminoethyl)amino]-2-propanol (HL), [Co(L)(H2O)](ClO4)2 (1), [Ni(HL)](ClO4)2 (2), as well as the known complex [Cu(HL)](ClO4)2 (3) for comparison. Their abilities to catalyze the dismutation of H2O2 and the oxidation of cyclohexane were investigated. The complexes were characterized by X-ray diffraction, elemental analysis, electronic and infrared spectroscopy, cyclic voltammetry, electrospray ionization mass spectrometry (ESI-MS) and conductivity measurements. The X-ray structures showed that the nickel (2) and copper (3) complexes are tetracoordinated, with the metal ion bound to the nitrogen atoms of the ligand. On the other hand, the cobalt complex (1) is hexacoordinated, possessing additional bonds to the alkoxo group of the ligand and to a water molecule. Neither of the complexes was able to catalyze the oxidation of cyclohexane, but all of them exhibited catalase-like activity, following Michaelis-Menten kinetics, which suggest resemblance with the catalase natural enzymes. The catalytic activity followed the order: [Ni(HL)](ClO4)2 (2) > [Cu(HL)](ClO4)2 (3) > [Co(L)(H2O)](ClO4)2 (1). As far as we know, this is the first description of a nickel complex presenting a significant catalase-like activity. PMID:26379038

  3. Synthesis, characterization and biological activity of complexes of 2-hydroxy-3,5-dimethylacetophenoneoxime (HDMAOX) with copper(II), cobalt(II), nickel(II) and palladium(II)

    NASA Astrophysics Data System (ADS)

    Singh, Bibhesh K.; Jetley, Umesh K.; Sharma, Rakesh K.; Garg, Bhagwan S.

    2007-09-01

    A new series of complexes of 2-hydroxy-3,5-dimethyl acetophenone oxime (HDMAOX) with Cu(II), Co(II), Ni(II) and Pd(II) have been prepared and characterized by different physical techniques. Infrared spectra of the complexes indicate deprotonation and coordination of the phenolic OH. It also confirms that nitrogen atom of the oximino group contributes to the complexation. Electronic spectra and magnetic susceptibility measurements reveal square planar geometry for Cu(II), Ni(II) and Pd(II) complexes and tetrahedral geometry for Co(II) complex. The elemental analyses and mass spectral data have justified the ML 2 composition of complexes. Kinetic and thermodynamic parameters were computed from the thermal decomposition data using Coats and Redfern method. The geometry of the metal complexes has been optimized with the help of molecular modeling. The free ligand (HDMAOX) and its metal complexes have been tested in vitro against Alternarie alternate, Aspergillus flavus, Aspergillus nidulans and Aspergillus niger fungi and Streptococcus, Staph, Staphylococcus and Escherchia coli bacteria in order to assess their antimicrobial potential. The results indicate that the ligand and its metal complexes possess antimicrobial properties.

  4. Complexes of 2,6-bis[N-(2'-pyridylmethyl)carbamyl]pyridine: formation of mononuclear complexes, and self-assembly of double helical dinuclear and tetranuclear copper(II) and trinuclear nickel(II) complexes.

    PubMed

    Alcock, Nathaniel W; Clarkson, Guy; Glover, Peter B; Lawrance, Geoffrey A; Moore, Peter; Napitupulu, Mery

    2005-02-01

    The potentially pentadentate ligand 2,6-bis[N-(2'-pyridylmethyl)carbamyl]pyridine (H2L1), readily prepared from reaction of a diester of pyridine-2,6-dicarboxylic acid (H2dipic) and 2-aminomethylpyridine (ampy), shows limited tendency to form 1:1 M:L complexes with labile metal ions, although [CuL1] and [NiL1] were observed as minor species, the latter characterized by a crystal structure analysis. A mononuclear complex formed with inert Co(III) was characterized by a crystal structure as the neutral 1:2 complex [Co(L1)(HL1)] with two ligands acting as tridentate ligands, one coordinated by the central pyridine and its two flanking deprotonated amido groups, and the other by the central pyridine, one amido and one terminal pyridine group, with the remaining poorly coordinating protonated amide remaining unbound along with other terminal pyridine groups. Fe(III) is known to form a symmetrical 1:2 complex, but that complex is anionic due to binding of all four deprotonated amido groups; the unsymmetrical neutral Co(III) complex converts into a symmetrical anionic species only on heating for hours in aqueous base in the presence of activated carbon. The most remarkable tendency of H2L1, however, is towards the formation of robust double helical complexes: a dinuclear Cu(II) complex [Cu2L1(2)] forms, as well as a trinuclear Ni(II) complex [Ni(3)(L1)2(OAc)2(MeOH)2]. Moreover, in the presence of added H2dipic, the tetranuclear complex [Cu4(L1)2(dipic)2(OH2)2] is obtained. All helical complexes have been characterized by X-ray crystal structure analyses, and all crystals feature a racemic mixture of left- and right-handed double helices stabilized by inter-ligand pi-stacking (inter-ring distances of 3.2-3.8 A) of ligands which each span several metal ions. Using the chelating ligand pentane-2,4-dione (acac), each of the two pairs of adjacent monodentate ligands in [Ni3(L1)2(OAc)2(OH2)2] have been shown to be available for substitution without destroying the helical structure, to form [Ni3(L1)2(acac)2], also characterized by a crystal structure. PMID:15672196

  5. Synthesis and Characterization of Cobalt(III), Nickel(II) and Copper(II) Mononuclear Complexes with the Ligand 1,3-bis[(2-aminoethyl)amino]-2-propanol and Their Catalase-Like Activity.

    PubMed

    Pires, Bianca M; Silva, Daniel M; Visentin, Lorenzo C; Rodrigues, Bernardo L; Carvalho, Nakédia M F; Faria, Roberto B

    2015-01-01

    In this work, we present the synthesis and characterization of two new mononuclear complexes with the ligand 1,3-bis[(2-aminoethyl)amino]-2-propanol (HL), [Co(L)(H2O)](ClO4)2 (1), [Ni(HL)](ClO4)2 (2), as well as the known complex [Cu(HL)](ClO4)2 (3) for comparison. Their abilities to catalyze the dismutation of H2O2 and the oxidation of cyclohexane were investigated. The complexes were characterized by X-ray diffraction, elemental analysis, electronic and infrared spectroscopy, cyclic voltammetry, electrospray ionization mass spectrometry (ESI-MS) and conductivity measurements. The X-ray structures showed that the nickel (2) and copper (3) complexes are tetracoordinated, with the metal ion bound to the nitrogen atoms of the ligand. On the other hand, the cobalt complex (1) is hexacoordinated, possessing additional bonds to the alkoxo group of the ligand and to a water molecule. Neither of the complexes was able to catalyze the oxidation of cyclohexane, but all of them exhibited catalase-like activity, following Michaelis-Menten kinetics, which suggest resemblance with the catalase natural enzymes. The catalytic activity followed the order: [Ni(HL)](ClO4)2 (2) > [Cu(HL)](ClO4)2 (3) > [Co(L)(H2O)](ClO4)2 (1). As far as we know, this is the first description of a nickel complex presenting a significant catalase-like activity. PMID:26379038

  6. Efficient electron-induced removal of oxalate ions and formation of copper nanoparticles from copper(II) oxalate precursor layers.

    PubMed

    Rückriem, Kai; Grotheer, Sarah; Vieker, Henning; Penner, Paul; Beyer, André; Gölzhäuser, Armin; Swiderek, Petra

    2016-01-01

    Copper(II) oxalate grown on carboxy-terminated self-assembled monolayers (SAM) using a step-by-step approach was used as precursor for the electron-induced synthesis of surface-supported copper nanoparticles. The precursor material was deposited by dipping the surfaces alternately in ethanolic solutions of copper(II) acetate and oxalic acid with intermediate thorough rinsing steps. The deposition of copper(II) oxalate and the efficient electron-induced removal of the oxalate ions was monitored by reflection absorption infrared spectroscopy (RAIRS). Helium ion microscopy (HIM) reveals the formation of spherical nanoparticles with well-defined size and X-ray photoelectron spectroscopy (XPS) confirms their metallic nature. Continued irradiation after depletion of oxalate does not lead to further particle growth giving evidence that nanoparticle formation is primarily controlled by the available amount of precursor. PMID:27547602

  7. Efficient electron-induced removal of oxalate ions and formation of copper nanoparticles from copper(II) oxalate precursor layers

    PubMed Central

    Rückriem, Kai; Grotheer, Sarah; Vieker, Henning; Penner, Paul; Beyer, André; Gölzhäuser, Armin

    2016-01-01

    Summary Copper(II) oxalate grown on carboxy-terminated self-assembled monolayers (SAM) using a step-by-step approach was used as precursor for the electron-induced synthesis of surface-supported copper nanoparticles. The precursor material was deposited by dipping the surfaces alternately in ethanolic solutions of copper(II) acetate and oxalic acid with intermediate thorough rinsing steps. The deposition of copper(II) oxalate and the efficient electron-induced removal of the oxalate ions was monitored by reflection absorption infrared spectroscopy (RAIRS). Helium ion microscopy (HIM) reveals the formation of spherical nanoparticles with well-defined size and X-ray photoelectron spectroscopy (XPS) confirms their metallic nature. Continued irradiation after depletion of oxalate does not lead to further particle growth giving evidence that nanoparticle formation is primarily controlled by the available amount of precursor. PMID:27547602

  8. Spectroscopic investigation of the noncovalent association of the nerve agent simulant diisopropyl methylphosphonate (DIMP) with zinc(II) porphyrins.

    PubMed

    Maza, William A; Vetromile, Carissa M; Kim, Chungsik; Xu, Xue; Zhang, X Peter; Larsen, Randy W

    2013-11-01

    Organophosphonates pose a significant threat as chemical warfare agents, as well as environmental toxins in the form of pesticides. Thus, methodologies to sense and decontaminate these agents are of significant interest. Porphyrins and metalloporphyrins offer an excellent platform to develop chemical threat sensors and photochemical degradation systems. These highly conjugated planar molecules exhibit relatively long-lived singlet and triplet states with high quantum yields and also form self-associated complexes with a wide variety of molecules. A significant aspect of porphyrins is the ability to functionalize the peripheral ring system either directly to the pyrrole rings or to the bridging methine carbons. In this report, steady-state absorption and fluorescence are utilized to probe binding affinities of a series of symmetric and asymmetric zinc(II) metalloporphyrins for the nerve agent simulant diisopropyl methylphosphonate (DIMP) in hexane. The red shifts in the absorption and emission spectra observed for all of the metalloporphyrins probed are discussed in the frame of Gouterman's four orbital model and a common binding motif involving coordination between the metalloporphyrin and DIMP via interaction between the zinc metal center of the porphyrin and phosphoryl oxygen of DIMP (Zn-O═P) is proposed. PMID:24093669

  9. Thermolysis preparation of ZnS nanoparticles from a nano-structure bithiazole zinc(II) coordination compound

    NASA Astrophysics Data System (ADS)

    Hosseinian, Akram; Rahimipour, Hamid Reza; Haddadi, Hedayat; Ashkarran, Ali Akbar; Mahjoub, Ali Reza

    2014-09-01

    Nano-scale and single crystals of a new tris-chelate Zn(II) compound, {[Zn(DADMBTZ)3](SCN)2ṡ4H2O}n, (1), {DADMBTZ = 2,2‧-diamino-5,5‧-dimethyl-4,4‧-bithiazole} have been synthesized by the reaction of zinc(II) sulfate, ammonium thiocyanate and DADMBTZ using sonochemical and branched tube methods, respectively. The new nanoparticles were characterized by scanning electron microscopy (SEM), X-ray powder diffraction (XRD) and FT-IR spectroscopy. Compound (1) was structurally characterized by single crystal X-ray diffraction. Compound (1) form a tris-chelate complex with nearly C3 symmetry. The coordination number of zinc atom in the compound is six with coordinated environments of distorted octahedral, ZnN6. In reaction with DADMBTZ, the ligand DADMBTZ acts as bidentate in compound to form five-membered chelate rings with the same internal angles in coordination polyhedron. The crystal packing is mainly stabilized by N-H- - - -N hydrogen bonding interactions. The thermal stability of compound (1) was studied by thermal gravimetric (TG) and differential thermal analyses (DTA). ZnS nanostructures were obtained by direct thermolyses of compound (1) at 400 °C under argon atmosphere. The ZnS nanoparticles were characterized by scanning electron microscopy (SEM), X-ray powder diffraction (XRD) and Fourier transform infrared (FT-IR) spectroscopy.

  10. Zinc(II) and Cadmium(II) complexes with N4-coordinate pyrazole based ligand: Syntheses, characterization and structure

    NASA Astrophysics Data System (ADS)

    Solanki, Ankita; Sadhu, Mehul H.; Kumar, Sujit Baran; Mitra, Partho

    2014-11-01

    A series of six new mononuclear zinc(II) complexes of the type [Zn(X)(dbdmp)]Y (1-6) (X = N3-/NCO-/NCS-, Y = ClO4-/PF6-, and dbdmp = N,N-diethyl-N‧,N‧-bis((3,5-dimethyl-1H-pyrazol-1-yl)methyl)ethane-1,2-diamine), two binuclear cadmium(II) complexes [{Cd(dbdmp)}2(μ-N3)2](Y)2 (7-8) and three mononuclear cadmium(II) complexes [Cd(NCO)(dbdmp)]Y (Y = ClO4-/PF6-) (9-10) and [Cd(NCS)2(dbdmp)] (11) have been synthesized and characterized by physico-chemical methods. Crystal structures of the complexes [Zn(N3)(dbdmp)]ClO4 (1), [{Cd(dbdmp)}2(μ-N3)2](ClO4)2 (7), [Cd(NCO)(dbdmp)]ClO4 (9) and [Cd(NCS)2(dbdmp)] (11) have been solved by single crystal X-ray diffraction studies and showed that [Zn(N3)(dbdmp)]ClO4 (1) and [Cd(NCO)(dbdmp)]ClO4 (9) have distorted trigonal bipyramidal geometry, [Cd(NCS)2(dbdmp)] (11) and [(dbdmp)Cd(μ-N3)]2(ClO4)2 (7) have distorted octahedral geometry.

  11. Redox noninnocence of the bridge in copper(II) salophen and bis(oxamato) complexes.

    PubMed

    de Bellefeuille, David; Orio, Maylis; Barra, Anne-Laure; Aukauloo, Ally; Journaux, Yves; Philouze, Christian; Ottenwaelder, Xavier; Thomas, Fabrice

    2015-09-21

    Two square-planar copper(II) complexes of 1,2-bis(2-hydroxy-3,5-di-tert-butylbenzimino)-4,5-bis(dimethylamino)benzene (1) and N-[4,5-bis(dimethylamino)-2-(oxalylamino)benzene]oxamate (2(2-)) were prepared. The crystal structures of the proligands H2L(1) and Et2H2L(2), as well as the corresponding complexes, are reported. The proligands each display a one-electron-oxidation wave, which is assigned to oxidation of the bis(dimethylamino)benzene moiety into a π radical. Complexes 1 and 2(2-) exhibit reversible one-electron-oxidation waves in their cyclic voltammograms (E1/2(1) = 0.14 and E1/2(2) = 0.31 V for 1 and E1/2(1) = -0.47 V vs Fc(+)/Fc for 2(2-)). The first process corresponds to oxidation of the bis(dimethylamino)benzene central ring into a π radical, while the second process for 1 is ascribed to oxidation of the π radical into an α-diiminoquinone. The one-electron-oxidized species 1(+) and 2(-) exhibit intense visible-near-IR absorptions, which are diagnostic of π radicals. They display a triplet signal in their electron paramagnetic resonance spectra, which stem from magnetic coupling between the ligand-radical spin and the copper(II) spin. The zero-field-splitting parameters are larger for 2(-) than 1(+) because of greater delocalization of the spin density onto the coordinated amidato N atoms. Density functional theory calculations support a π-radical nature of the one-electron-oxidized complexes, as well as S = 1 ground spin states. The electrogenerated 1(2+) comprises a closed-shell diiminoquinone ligand coordinated to a copper(II) metal center. Both 1 and 2 catalyze the aerobic oxidation of benzyl alcohol, albeit with different yields. PMID:26340100

  12. Characterization of the Copper(II) Binding Sites in Human Carbonic Anhydrase II

    PubMed Central

    Nettles, Whitnee L.; Song, He; Farquhar, Erik R.; Fitzkee, Nicholas C.; Emerson, Joseph P.

    2015-01-01

    Human carbonic anhydrase (CA) is a well-studied, robust, mononuclear Zn-containing metalloprotein that serves as an excellent biological ligand system to study the thermodynamics associated with metal ion coordination chemistry in aqueous solution. The apo-form of human carbonic anhydrase II (CA) binds two equivalents of copper(II) with high affinity. The Cu2+ ions bind independently forming two non-coupled type-II copper centers in CA (CuA and CuB). However, the location and coordination mode of the CuA site in solution is unclear, compared to the CuB site that has been well characterized. Using paramagnetic NMR techniques and X-ray absorption spectroscopy we have identified an N-terminal Cu2+ binding location and collected information on the coordination mode of the CuA site in CA, which is consistent with a four to five coordinate N-terminal Cu2+ binding site reminiscent to a number of N-terminal copper(II) binding sites including the copper(II)-ATCUN and copper(II)-beta-amyloid complexes. Additionally, we report a more detailed analysis of the thermodynamics associated with copper(II) binding to CA. Although we are still unable to fully deconvolute Cu2+ binding data to the high-affinity CuA site, we have derived pH- and buffer-independent values for the thermodynamics parameters K and ΔH associated with Cu2+ binding to the CuB site of CA to be 2 × 109 and −17.4 kcal/mol, respectively. PMID:26010488

  13. A Fluorescent Indicator for Imaging Lysosomal Zinc(II) with Förster Resonance Energy Transfer (FRET)-Enhanced Photostability and a Narrow Band of Emission

    PubMed Central

    Sreenath, Kesavapillai; Yuan, Zhao; Allen, John R.

    2015-01-01

    We demonstrate a strategy to transfer the zinc(II) sensitivity of a fluoroionophore with low photostability and a broad emission band to a bright and photostable fluorophore with a narrow emission band. The two fluorophores are covalently connected to afford an intramolecular Förster resonance energy transfer (FRET) conjugate. The FRET donor in the conjugate is a zinc(II)-sensitive arylvinylbipyridyl fluoroionophore, the absorption and emission of which undergo bathochromic shifts upon zinc(II) coordination. When the FRET donor is excited, efficient intramolecular energy transfer occurs to result in the emission of the acceptor boron dipyrromethene (4,4-difluoro-4-bora-3a,4a-diaza-s-indacene or BODIPY) as a function of zinc(II) concentration. The broad emission band of the donor/zinc(II) complex is transformed into the strong, narrow emission band of the BODIPY acceptor in the FRET conjugates, which can be captured within the narrow emission window that is preferred for multicolor imaging experiments. In addition to competing with other nonradiative decay processes of the FRET donor, the rapid intramolecular FRET of the excited FRET-conjugate molecule protects the donor fluorophore from photobleaching, thus enhancing the photostability of the indicator. FRET conjugates 3 and 4 contain aliphatic amino groups, which selectively target lysosomes in mammalian cells. This subcellular localization preference was verified by using confocal fluorescence microscopy, which also shows the zinc(II)-enhanced emission of 3 and 4 in lysosomes. It was further shown using two-color structured illumination microscopy (SIM), which is capable of extending the lateral resolution over the Abbe diffraction limit by a factor of two, that the morpholino-functionalized compound 4 localizes in the interior of lysosomes, rather than anchoring on the lysosomal membranes, of live HeLa cells. PMID:25382395

  14. The speciation of aqueous zinc(II) bromide solutions to 500 °C and 900 MPa determined using Raman spectroscopy

    USGS Publications Warehouse

    Mibe, Kenji; Chou, I-Ming; Anderson, Alan J.; Mayanovic, Robert A.; Bassett, William A.

    2009-01-01

    A Raman spectral study was carried out on 3 solutions of varying concentration and bromide/zinc ratios. Spectra were collected at 11 different temperature-pressure conditions ranging from ambient to 500????C-0.9??GPa. Raman band assignments for zinc(II) bromide species reported in previous studies were used to determine the relative concentrations of ZnBr42-, ZnBr3-, ZnBr2, and ZnBr+ species at various temperatures and pressures. Our results are in close agreement with X-ray absorption spectroscopic (XAS) data, and confirm that the tetrabromo zinc(II) complex, ZnBr42-, is the predominant species up to 500????C in solutions having high Zn concentrations (1??m) and high bromide/zinc molar ratios ([Br]/[Zn] = 8). In agreement with previous solubility and Raman spectroscopic experiments, our measurements indicate that species with a lower number of halide ligands and charge are favored with increasing temperature in dilute solutions, and solutions with low bromide/zinc ratios ([Br]/[Zn] < 2.5). The Raman technique provides an independent experimental means of evaluating the quality of XAS analyses of data obtained from high temperature disordered systems. The combination of these two techniques provides complementary data on speciation and the structure of zinc(II) bromide complexes. The preponderance of the ZnBr42- species in highly saline brines at high temperature is consistent with the predominance of ZnCl42- in chloride-rich brines reported in previous XAS studies. Knowledge of Zn complexing in metal-rich highly saline brines is important for numerical models of ore deposition in high temperature systems such as skarns and porphyry-type deposits. ?? 2008 Elsevier B.V.

  15. Copper(II) ions and the Alzheimer's amyloid-β peptide: Affinity and stoichiometry of binding

    NASA Astrophysics Data System (ADS)

    Tõugu, Vello; Friedemann, Merlin; Tiiman, Ann; Palumaa, Peep

    2014-10-01

    Deposition of amyloid beta (Aβ) peptides into amyloid plaques is the hallmark of Alzheimer's disease. According to the amyloid cascade hypothesis this deposition is an early event and primary cause of the disease, however, the mechanisms that cause this deposition remain elusive. An increasing amount of evidence shows that the interactions of biometals can contribute to the fibrillization and amyloid formation by amyloidogenic peptides. From different anions the copper ions deserve the most attention since it can contribute not only toamyloid formation but also to its toxicity due to the generation of ROS. In this thesis we focus on the affinity and stoichiometry of copper(II) binding to the Aβ molecule.

  16. 2D NMR Methods for Structural Delineation of Copper(II) Complexes of Penicillin and Pilocarpine

    PubMed Central

    Gaggelli, Elena; Gaggelli, Nicola

    1994-01-01

    A method was developed for delineating the structure of paramagnetic metal complexes. The selective disappearance of cross-peaks in proton-carbon shift correlated 2D NMR maps was shown to uniquely depend upon the scalar and/or dipolar interaction between ligand nuclei and the unpaired electron(s), thus providing a means of identifying binding sites. Copper(II) was shown to form metal complexes with both Penicillin (PNC) and Pilocarpine (PLC) and the structure of the two 1:2 complexes in water solution at physiological pH were determined. PMID:18476239

  17. EPR, mass, IR, electronic, and magnetic studies on copper(II) complexes of semicarbazones and thiosemicarbazones

    NASA Astrophysics Data System (ADS)

    Chandra, Sulekh; Gupta, Lokesh Kumar

    2005-01-01

    Copper(II) complexes having the general composition Cu(L) 2X 2 [where L = isopropyl methyl ketone semicarbazone (LLA), isopropyl methyl ketone thiosemicarbazone (LLB), 4-aminoacetophenone semicarbazone (LLC), and 4-aminoacetophenone thiosemicarbazone (LLD) and X = Cl -, 1/2SO 42-] have been synthesized. All the Cu(II) complexes reported here have been characterized by elemental analyses, molar conductance, magnetic moment susceptibility, EI mass, 1H NMR, IR, EPR, and electronic spectral studies. All the complexes were found to have magnetic moments corresponding to one unpaired electrons. The possible geometries of the complexes were assigned on the basis of EPR, electronic, and infrared spectral studies.

  18. The toxicity of copper(II) species to marine algae, with particular reference to macroalgae

    SciTech Connect

    Gledhill, M.; Nimmo, M.; Hill, S.J.; Brown, M.T.

    1997-02-01

    Ambient concentrations of dissolved copper(II) in seawater are very low. However, levels can increase as a result of natural and anthropogenic sources. Such increase can have profound effects on organisms in the vicinity resulting in inhibition of growth, reduced fecundity, and even death. This paper highlights the importance of pecieation when considering the toxic effects of cooper, with particular reference to macroalgae in a marine environment, and to encourage more biologists to take account of this in their studies of metal pollution. 104 refs., 2 figs., 4 tabs.

  19. LC-MS and GC-MS metabolite profiling of nickel(II) complexes in the latex of the nickel-hyperaccumulating tree Sebertia acuminata and identification of methylated aldaric acid as a new nickel(II) ligand.

    PubMed

    Callahan, Damien L; Roessner, Ute; Dumontet, Vincent; Perrier, Nicolas; Wedd, Anthony G; O'Hair, Richard A J; Baker, Alan J M; Kolev, Spas D

    2008-01-01

    Targeted liquid chromatography-mass spectrometry (LC-MS) technology using size exclusion chromatography and metabolite profiling based on gas chromatography-mass spectrometry (GC-MS) were used to study the nickel-rich latex of the hyperaccumulating tree Sebertia acuminata. More than 120 compounds were detected, 57 of these were subsequently identified. A methylated aldaric acid (2,4,5-trihydroxy-3-methoxy-1,6-hexan-dioic acid) was identified for the first time in biological extracts and its structure was confirmed by 1D and 2D nuclear magnetic resonance (NMR) spectroscopy. After citric acid, it appears to be one of the most abundant small organic molecules present in the latex studied. Nickel(II) complexes of stoichiometry NiII:acid=1:2 were detected for these two acids as well as for malic, itaconic, erythronic, galacturonic, tartaric, aconitic and saccharic acids. These results provide further evidence that organic acids may play an important role in the transport and possibly in the storage of metal ions in hyperaccumulating plants. PMID:17765935

  20. Effects of terminal dimethylation and metal coordination of proline-2-formylpyridine thiosemicarbazone hybrids on lipophilicity, antiproliferative activity, and hR2 RNR inhibition.

    PubMed

    Bacher, Felix; Dömötör, Orsolya; Kaltenbrunner, Maria; Mojović, Miloš; Popović-Bijelić, Ana; Gräslund, Astrid; Ozarowski, Andrew; Filipovic, Lana; Radulović, Sinisa; Enyedy, Éva A; Arion, Vladimir B

    2014-12-01

    The nickel(II), copper(II), and zinc(II) complexes of the proline-thiosemicarbazone hybrids 3-methyl-(S)-pyrrolidine-2-carboxylate-2-formylpyridine thiosemicarbazone (L-Pro-FTSC or (S)-H2L(1)) and 3-methyl-(R)-pyrrolidine-2-carboxylate-2-formylpyridine thiosemicarbazone (D-Pro-FTSC or (R)-H2L(1)), as well as 3-methyl-(S)-pyrrolidine-2-carboxylate-2-formylpyridine 4,4-dimethyl-thiosemicarbazone (dm-L-Pro-FTSC or (S)-H2L(2)), namely, [Ni(L-Pro-FTSC-2H)]2 (1), [Ni(D-Pro-FTSC-2H)]2 (2), [Ni(dm-L-Pro-FTSC-2H)]2 (3), [Cu(dm-L-Pro-FTSC-2H)] (6), [Zn(L-Pro-FTSC-2H)] (7), and [Zn(D-Pro-FTSC-2H)] (8), in addition to two previously reported, [Cu(L-Pro-FTSC-2H)] (4), [Cu(D-Pro-FTSC-2H)] (5), were synthesized and characterized by elemental analysis, one- and two-dimensional (1)H and (13)C NMR spectroscopy, circular dichroism, UV-vis, and electrospray ionization mass spectrometry. Compounds 1-3, 6, and 7 were also studied by single-crystal X-ray diffraction. Magnetic properties and solid-state high-field electron paramagnetic resonance spectra of 2 over the range of 50-420 GHz were investigated. The complex formation processes of L-Pro-FTSC with nickel(II) and zinc(II) were studied in aqueous solution due to the excellent water solubility of the complexes via pH potentiometry, UV-vis, and (1)H NMR spectroscopy. The results of the antiproliferative activity in vitro showed that dimethylation improves the cytotoxicity and hR2 RNR inhibition. Therefore, introduction of more lipophilic groups into thiosemicarbazone-proline backbone becomes an option for the synthesis of more efficient cytotoxic agents of this family of compounds. PMID:25391085

  1. Structural characterization and EPR spectral studies on mononuclear copper(II) complex of saccharin with ethylnicotinate

    NASA Astrophysics Data System (ADS)

    Uçar, İbrahim; Bozkurt, Esat; Kazak, Canan; Bulut, Ahmet

    2009-02-01

    Mononuclear copper(II) saccharinate (sac) complex containing ethylnicotinate (enc), [Cu(enc) 2(sac) 2(H 2O)]·1.4H 2O has been synthesized and characterized by spectroscopic (IR, UV-vis, EPR), X-ray diffraction technique and electrochemical methods. It crystallizes in the tetragonal crystal systems with space group I4 1cd and Z = 8. The copper(II) ion presents a CuN 4O distorted square pyramidal coordination. Based on EPR and optical absorption studies, spin-Hamiltonian and bonding parameters have been calculated. The g-values, calculated for title complex in polycrystalline state at 298 K and in frozen DMF (110 K), indicate the presence of the unpaired electron in the d orbital. The evaluated metal-ligand bonding parameters showed strong in-plane σ and in-plane π-bonding. Some comparisons with related structures are made and the most important features of its IR spectrum were also discussed. The cyclic voltammogram of the title complex investigated in DMF (dimethylformamide) solution exhibits only metal centred electroactivity in the potential range ±1.25 V vs. Ag/AgCl reference electrode.

  2. The structure of amorphous bulk and silica-supported copper(II) hydroxides

    SciTech Connect

    Kriventsov, V.V.; Kochubey, D.I.; Elizarova, G.L.; Matvienko, L.G.; Parmon, V.N.

    1999-07-01

    Determination of the structure of surface hydroxocompounds is one of the most delicate areas of environmental chemistry, geochemistry, and catalysis. In nature, these compounds are formed everywhere, mostly by absorption of multicharged metal cations on different soil constitutents from water solutions. The data obtained show that at pH 7 copper(II) ions are adsorbed on a SiO{sub 2} surface as polymeric species of hydroxide nature. The structure of these species is similar to that of the bulk amorphous copper hydroxide. The amorphous state of supported Cu(OH){sub 2} is caused by a small (ca. 11 {angstrom}) size of the surface particles. In contrast, the overstoichiometric water molecules seem to act as ``amorphizers`` of the bulk copper hydroxide. The structures of the bulk and dispersed amorphous copper(II) hydroxide were determined. The amorphous Cu(OH){sub 2} has a layered structure close to the structure of the crystalline hydroxide, but the layers in the amorphous hydroxide are shifted toward one another approximately for {1/4} of the c period of the lattice.

  3. Synthesis, structure and spectroscopic properties of an o-phthalate-bridged copper(II) chain complex

    NASA Astrophysics Data System (ADS)

    Zhang, Y.; Li, J.; Su, Q.; Wang, Q.; Wu, X.

    2000-01-01

    An o-phthalate-bridged copper(II) chain complex of {[Cu(2,2'-bipyridine)(μ-phthalate)H 2O]·3.5H 2O} n has been prepared and characterized by X-ray crystallography and UV-vis spectroscopy measurements. It crystallizes in the monoclinic system, space group P2 1/c, with a=9.9585(5), b=14.8312(8), c=13.6875(7) Å, β=104.868(1)° and Z=4. The copper(II) center is in 4+1 surrounding that can be described as square-pyramid. Each Cu(II) atom links by o-phthalate to form a waving chain. A network structure is assembled by chains via π-π interactions and water molecules are clathrated in the cavities. The UV-vis absorption spectrum of the title complex is also reported and explained perfectly by the scaling radial theory which was proposed by us.

  4. Recognition of oxalate by a copper(II) polyaza macrobicyclic complex.

    PubMed

    Mateus, Pedro; Delgado, Rita; Brandão, Paula; Félix, Vítor

    2011-06-14

    A new polyamine macrobicyclic compound was synthesised through a [1+1] "tripod-tripod coupling" strategy and using a Schiff base condensation reaction, followed by sodium borohydride reduction. The resulting compound is a heteroditopic cage (btpN(7)) in which one of the head units is appropriate for the coordination of copper(II), whereas the other head is available for additional hydrogen-bonding and electrostatic interactions with substrates. The acid-base behaviour of the new compound, the stability constants of its complex with the Cu(2+) ion and the association constants of the copper(II) cryptate with oxalate (oxa(2-)), malonate (mal(2-)), succinate (suc(2-)), maleate (male(2-)) and fumarate (fum(2-)) were determined by potentiometry at 298.2 K in aqueous solution and at an ionic strength of 0.10 mol dm(-3) in KNO(3). These studies revealed a clear preference of the receptor [CuH(h)btpN(7)H(2)O]((2+h)+) for oxa(2-) over the other dicarboxylate substrates. This arises from co-operativity between metal-anion coordination and electrostatic and hydrogen-bonding interactions, in accordance with the ideal size of this dicarboxylate, which allow it to take full advantage of the potential binding sites of the receptor. A qualitative indicator-displacement study, in agreement with the potentiometric studies, demonstrated that the copper cryptate receptor can be used as a selective visual sensor for oxalate. PMID:21557358

  5. Dialkyl pyridinedicarboxylates` extraction ability toward copper(II) from chloride solutions and its modification with alcohols

    SciTech Connect

    Bogacki, M.B.; Jakubiak, A.; Szymanowski, J.; Cote, G.

    1997-03-01

    Dipentyl pyridinedicarboxylates (denoted hereafter as L) with different positions of the ester groups were synthesized and used for copper(II) extraction from chloride solutions containing up to 10 mol/L Cl{sup {minus}}. The effect of decanol addition on copper extraction was studied. A molecular modeling technique was used to estimate the structures of extractants, copper complexes, and associates with alcohol. It was found that the ability of pyridinecarboxylates to extract copper depends on the aqueous phase composition and the position of the ester groups in the pyridine ring. All the investigated compounds except dipentyl pyridine-2,6-dicarboxylate extract copper(II) by formation of CuCl{sub 2}L{sub 2} complexes. Dipentyl pyridine-2,6-dicarboxylate forms another type of complex, probably CuCl{sub 2}L. However, this compound is not suitable for copper extraction as its copper complex precipitates. Dipentyl pyridine-3,5-dicarboxylate was found to be the most suitable extractant among the various compounds listed. Finally it is shown that the possibilities to modify the extraction ability of pyridinecarboxylates with a hydrophobic alcohol such as decanol are relatively weak. Some enhancement was, however, observed when 20% of decanol was added to the organic phase containing dipentyl pyridine-3,5-dicarboxylate.

  6. Synthesis, Crystal structure, and Hirshfeld Surface Analysis of a New Mixed Ligand Copper(II) Complex.

    PubMed

    Shit, Shyamapada; Marschner, Christoph; Mitra, Samiran

    2016-01-01

    A new mixed ligand copper(II) complex, [Cu(2,4-pydc)(pic)(H(2)O)]∙H(2)O (1) (where 2,4-pydc = pyridine-2,4-dicarboxylate, pic = 2-picolylamine) has been synthesized and characterized by elemental analysis, FT-IR and UV-Vis spectroscopic and thermogravimetric methods. Single crystal X-ray diffraction analysis reveals that copper(II) atom in the title complex adopts distorted square pyramidal geometry. Structural characterization also reveals that interplay of O-H···O, N-H···O, C-H···O, and C-H···π interactions between lattice and coordinated water and ligands significantly contribute to the crystal packing leading to the formation and strengthening of three dimensional supramolecular assembly. Hirshfeld surface analysis employing 3D molecular surface contours and 2D fingerprint plots have been used to analyze intermolecular interactions present in the solid state of the crystal. PMID:26970797

  7. Synthesis, crystal structures and luminescent properties of zinc(II) metal–organic frameworks constructed from terpyridyl derivative ligand

    SciTech Connect

    Yang, Xiao-Le; Shangguan, Yi-Qing; Hu, Huai-Ming Xu, Bing; Wang, Bao-Cheng; Xie, Juan; Yuan, Fei; Yang, Meng-Lin; Dong, Fa-Xin; Xue, Gang-Lin

    2014-08-15

    Five zinc(II) metal–organic frameworks, [Zn{sub 3}(344-pytpy){sub 2}Cl{sub 6}]{sub n}·n(H{sub 2}O) (1), [Zn(344-pytpy)(ox)]{sub n} (2), [Zn{sub 2}(344-pytpy)(bdc){sub 2}]{sub n}·1.5n(H{sub 2}O) (3), [Zn{sub 2}(344-pytpy){sub 2} (sfdb){sub 2}]{sub n}·1.5n(H{sub 2}O) (4) and [Zn{sub 3}(344-pytpy){sub 2}(btc){sub 2}]{sub n}·2n(H{sub 2}O) (5), (344-pytpy=4′-(3-pyridyl)-4,2′:6′,4″-terpyridine, H{sub 2}ox=oxalic acid, H{sub 2}bdc=1,4-benzenedi-carboxylic acid, H{sub 2}sfdb=4,4′-sulfonyldibenzoic acid and H{sub 3}btc=1,3,5-benzene-tricarboxylic acid) have been prepared by hydrothermal reactions. Compound 1 is a 1D chain structure, in which 344-pytpy ligand links three Zn{sup II} centers through three of terminal N-donors. Compound 2 is a 4-connected 3D framework with the dia topological net and the Schläfli symbol of 6{sup 6}. Compound 3 displays a unusual 3-fold interpenetrating 3D coordination network which exhibits a new intriguing (3,3,4)-connected topological net with the Schläfli symbol of (4.8{sup 2})(4.8{sup 5})(8{sup 3}). Compound 4 features a two-fold interpenetrating 4-connected 2D framework with the sql topological net and the Schläfli symbol of (4{sup 4}.6{sup 2}). Compound 5 is a new self-interpenetrating (3,3,4,4)-connected topological net with the Schläfli symbol of (6.8{sup 2}){sub 2}(6{sup 2}.8{sup 2}.10.12)(6{sup 2}.8{sup 3}.10){sub 2}(6{sup 2}.8){sub 2}. The luminescence properties of 1–5 have been investigated by emission spectra and they possess great thermal stabilities which can be stable up to around 400 °C. - Graphical abstract: Five new Zn(II) metal–organic frameworks based on dicarboxylate and terpyridyl derivative ligands have been synthesized by hydrothermal reactions, giving networks from 1D to 3D structures. The thermal stability and luminescent property have been investigated. - Highlights: • Five zinc(II) metal–organic frameworks have been prepared under hydrothermal conditions. • Their crystal and

  8. Synthesis and characterization of bis nitrato[4-hydroxyacetophenonesemicarbazone) nickel(II) complex as ionophore for thiocyanate-selective electrode.

    PubMed

    Chandra, Sulekh; Hooda, Sunita; Tomar, Praveen Kumar; Malik, Amrita; Kumar, Ankit; Malik, Sakshi; Gautam, Seema

    2016-05-01

    The PVC based-ion selective electrode viz., bis nitrato[4-hydroxyacetophenone semicarbazone] nickel(II) as an ionophore was prepared for the determination of thiocyanate ion. The ionophore was characterized by FT-IR, UV-vis, XRD, magnetic moment and elemental analysis (CHN). On the basis of spectral studies an octahedral geometry has been assigned. The best performance was obtained with a membrane composition of 31% PVC, 63% 2-nitrophenyl octylether, 4.0% ionophore and 2.0% trioctylmethyl ammonium chloride. The electrode exhibited an excellent Nernstian response to SCN(-) ion ranging from 1.0 × 10(-7) to 1.0 × 10(-1)M with a detection limit of 8.6 × 10(-8)M and a slope of -59.4 ± 0.2 mV/decade over a wide pH range (1.8-10.7) with a fast response time (6s) at 25 °C. The proposed electrode showed high selectivity for thiocyanate ion over a number of common inorganic and organic anions. It was successfully applied to direct determination of thiocyanate in biological (urine and saliva) samples in order to distinguish between smokers and non-smokers, environmental samples and as an indicator electrode for titration of thiocyanate ions with AgNO3 solution. PMID:26952393

  9. Photo- and electroluminescent properties of zinc(II) complexes with tetradentate Schiff bases, derivatives of salicylic aldehyde

    NASA Astrophysics Data System (ADS)

    Vashchenko, A. A.; Lepnev, L. S.; Vitukhnovskii, A. G.; Kotova, O. V.; Eliseeva, S. V.; Kuz'mina, N. P.

    2010-03-01

    It is studied how the introduction of various substituents into the composition of organic ligands affects the photoluminescence spectra of new zinc(II) complexes with tetradentate Schiff bases H2L (derivatives of salicylic aldehyde (H2SAL1, H2SAL2) and o-vanillin (H2MO1, H2MO2) with ethylenediamine and o-phenylenediamine) in the form of bulk solids and thin films. It is demonstrated that the emission spectra of bulk solid complexes without o-phenylenediamine bridges (ZnSAL1 and ZnMO1) contain additional long-wavelength bands compared to the spectra of corresponding thin films. In the case of films obtained from [ZnSAL1]2 dimer complexes, the long-wavelength band is dominant. At the same time, the photoluminescence spectra of ZnSAL2 and ZnMO2 complexes with o-phenylenediamine bridges are similar in the case of solid samples and thin films. The electroluminescent properties of organic light-emitting diodes (OLEDs) with the ITO/α-NPD/ZnL/Ca:Al structure are studied. The bathochromic shift of the electroluminescence peaks of OLEDs with respect to the photoluminescence spectra of bulk solid samples and thin films is probably related to the formation of exciplexes at the α-NPD/ZnL interface. The electroluminescence spectra of OLEDs based on [ZnSAL1]2 show a hypsochromic shift of the emission maximum, which can be caused by a shift of the recombination region into the α-NPD layer.

  10. Photophysicals and photochemicals studies of zinc(II) phthalocyanine in long time circulation micelles for photodynamic therapy use.

    PubMed

    Sibata, M N; Tedesco, A C; Marchetti, J M

    2004-10-01

    Long time circulation systems, such as polymeric micelles, represent a growing area in biomedical research. These microparticles can be used in many biological systems to provide appropriate drug levels with a specific biodistribution. Long time circulation micelles (LTCM) were routinely prepared using PEG-5000-DSPE (polyethyleneglycol-5000-distearoil-phosphatidyl-ethanolamine) and zinc(II) phthalocyanine (ZnPc) as a photosensitizer and fluorescent probe. This compound belongs to a second generation of photoactive agents, mainly used in photodynamic therapy (PDT) of neoplasic tissues. Their high selectivity for tumoral target tissues as well as high phototoxicity based on singlet oxygen generation renders the utilization of these compounds feasible as an alternative therapy for cancer treatment. LTCM were characterized by classical spectroscopic techniques. Absorbance measurements indicated that the drug was s completely loaded into LTCM (epsilon = 2.41 x 10(5) cm(-1)). This was also verified by steady state and time-resolved fluorescence measurements. The lifetime profiles of ZnPc decay curves were fitted according to biexponential function (tau1 = 3.9 ns and tau2 = 15.5 ns) indicating different locations for ZnPc into LTCM. The time-resolved spectroscopy measurements for ZnPc triplet excited state lifetimes (tauT) were calculated from the kinetic analysis of transient decays at the absorption maximum (480 nm), by using laser flash photolysis technique. All the spectroscopy measurements performed allowed us to conclude that, ZnPc in LTCM is a promising drug delivery system (DDS) for PDT. PMID:15451001

  11. Efficient catalytic phosphate ester cleavage by binuclear zinc(II) pyrazolate complexes as functional models of metallophosphatases.

    PubMed

    Penkova, Larysa V; Maciag, Anna; Rybak-Akimova, Elena V; Haukka, Matti; Pavlenko, Vadim A; Iskenderov, Turganbay S; Kozłowski, Henryk; Meyer, Franc; Fritsky, Igor O

    2009-07-20

    A series of dizinc(II) complexes based on the pyrazolate ligands 3-[(1E)-N-hydroxyethanimidoyl]-4-methyl-1H-pyrazole-5-carboxylic acid (H(3)L(1)), (1E,1'E)-1,1'-(4-methyl-1H-pyrazole-3,5-diyl)diethanone dihydrazone (HL(2)), (E,E)-(4-methyl-1H-pyrazole-3,5-diyl)bis(methylmethanone) dioxime (H(3)L(3)), (E,E)-(4-phenyl-1H-pyrazole-3,5-diyl)bis(phenylmethanone) dioxime (H(3)L(4)), and 1H-pyrazole-3,5-dicarboxylic acid (H(3)L(5)) have been synthesized and investigated as functional models of phosphoesterases, focusing on correlations between the hydrolytic activity and molecular parameters of the bimetallic core. Speciation of the various dizinc complexes in solution has been determined potentiometrically, and the structures in the solid state have been established by X-ray crystallography. The hydrolysis of two phosphoesters, an RNA model 2-hydroxypropyl-p-nitrophenyl phosphate (HPNP) and the pesticide paraoxon-ethyl (POE), promoted by the dinuclear phosphoesterase model complexes has been investigated in DMSO/buffered water (1:1) at 50 degrees C as a function of complex concentration, substrate concentration, and pH. Drastic differences in the hydrolytic activities of [Zn(2)(HL(1))(2)](0), [Zn(2)(L(2))(2)](2+), [Zn(2)(H(2)L(3))(2)](2+), and [Zn(2)(HL(5))(2)](2-) are observed and can be attributed to molecular peculiarities. Pyrazolate-bridged dinuclear zinc(II) complexes seem to provide a sufficient number of coordination sites for both activating the substrate and generating the nucleophile, where the phosphate esters are preferentially bound in a bidentate bridging fashion (in the case of HPNP) and in a monodentate fashion (in the case of POE). PMID:19548638

  12. Chelation behavior of various flavonols and transfer of flavonol-chelated zinc(II) to alanylaspartic dipeptide: A PCM/DFT investigation

    NASA Astrophysics Data System (ADS)

    Yasarawan, Nuttawisit; Thipyapong, Khajadpai; Ruangpornvisuti, Vithaya

    2016-03-01

    Alanylaspartic dipeptide (AlaAsp) and zinc(II)-flavonol complex could represent a metal-binding site in proteins and a metal-ion releasing agent, respectively. Chelation of zinc(II) by either AlaAsp or flavonol ligands in aqueous solution has been examined using DFT methods with polarizable continuum model (PCM/DFT). Coordination geometry, complexation stoichiometry, coordination bond strength, preferable metal-binding site on ligands and effect of water coordination on the stability of complexes have been addressed. In several cases, the long-range corrected density functional CAM-B3LYP allows the most accurate prediction of both structural and spectroscopic data. The preferential transfer of flavonol-chelated zinc(II) to AlaAsp under solvation is attainable through the ligand-exchange reaction. The energy barrier of such reaction is significantly dependent on the degree of hydrogen bonding within the transition state. In summary, either hydroxylation or methoxylation at particular positions on the 3-hydroxyflavone backbone significantly affects the reactivity of flavonol chelates in the metal-ion transfer.

  13. Synthesis, spectroscopic characterisation, DNA cleavage, superoxidase dismutase activity and antibacterial properties of some transition metal complexes of a novel bidentate Schiff base derived from isatin and 2-aminopyrimidine.

    PubMed

    Nitha, L P; Aswathy, R; Mathews, Niecy Elsa; Kumari, B Sindhu; Mohanan, K

    2014-01-24

    Complexes of manganese(II), cobalt(II), nickel(II), copper(II) and zinc(II) with a Schiff base, formed by the condensation of isatin with 2-aminopyrimidine have been synthesised and characterised through elemental analysis, molar conductance measurements, magnetic susceptibility, IR, UV-Vis, (1)HNMR, FAB mass and EPR spectral studies. The spectral data revealed that the ligand acts as neutral bidentate, coordinating to the metal ion through the carbonyl oxygen and azomethine nitrogen. Molar conductance values adequately support the electrolytic nature of the complexes. On the basis of the above observations the complexes have been formulated as [M(ISAP)2]X2, where M=Mn(II), Co(II), Ni(II), Cu(II) and Zn(II); X=Cl, OAc; ISAP=2-[N-indole-2-one]aminopyrimidine. The ligand and copper(II) complex were subjected to X-ray diffraction studies. The DNA cleavage study was monitored by gel electrophoresis method. The superoxide dismutase (SOD) mimetic activities of the ligand and the metal complexes were checked using NBT assay. The in vitro antibacterial activity of the synthesized compounds has been tested against gram negative and gram positive bacteria. PMID:24051284

  14. Synthesis, spectroscopic characterisation, DNA cleavage, superoxidase dismutase activity and antibacterial properties of some transition metal complexes of a novel bidentate Schiff base derived from isatin and 2-aminopyrimidine

    NASA Astrophysics Data System (ADS)

    Nitha, L. P.; Aswathy, R.; Mathews, Niecy Elsa; Sindhu kumari, B.; Mohanan, K.

    2014-01-01

    Complexes of manganese(II), cobalt(II), nickel(II), copper(II) and zinc(II) with a Schiff base, formed by the condensation of isatin with 2-aminopyrimidine have been synthesised and characterised through elemental analysis, molar conductance measurements, magnetic susceptibility, IR, UV-Vis, 1HNMR, FAB mass and EPR spectral studies. The spectral data revealed that the ligand acts as neutral bidentate, coordinating to the metal ion through the carbonyl oxygen and azomethine nitrogen. Molar conductance values adequately support the electrolytic nature of the complexes. On the basis of the above observations the complexes have been formulated as [M(ISAP)2]X2, where M = Mn(II), Co(II), Ni(II), Cu(II) and Zn(II); X = Cl, OAc; ISAP = 2-[N-indole-2-one]aminopyrimidine. The ligand and copper(II) complex were subjected to X-ray diffraction studies. The DNA cleavage study was monitored by gel electrophoresis method. The superoxide dismutase (SOD) mimetic activities of the ligand and the metal complexes were checked using NBT assay. The in vitro antibacterial activity of the synthesized compounds has been tested against gram negative and gram positive bacteria.

  15. Synthesis, molecular orbital, optical and device characterization of mononuclear mixed ligand nickel(II) complex of phthalate with N,N,N‧,N‧-tetramethylethylenediamine for photodiode applications

    NASA Astrophysics Data System (ADS)

    Taha, A.; Farag, A. A. M.; Shebl, Magdy; Ammar, A. H.; Ahmed, H. M.

    2016-01-01

    In this work, a new synthesized mononuclear mixed ligand nickel(II) complex was characterized by various techniques. Crystalline characteristics of [Ni(Phth)(Me4en)(H2O)2]·4H2O were studied by using transmission electron microscope(TEM). Well crystalline structure corresponds to the hexagonal crystal system and identified by selected area electron diffraction (SAED) were achieved. Coordination of the nickel(II) ion with the functional groups of the ligands was established from the IR spectrum. Molar conductance of the current complex in DMF (10-3 mol/L) indicated a non-electrolytic nature of the complex. Electronic spectra showed a strong band in the region 661-684 nm; MeCN (661 nm), CHCl3 (663 nm), MeOH (667 nm), Me2CO (675 nm), DMSO (682 nm) and DMF (684 nm) which can be assigned to 3A2g(F) → 3T1g(F) transition of an octahedral structure around nickel(II). Multiple peaks were easily resolved from the spectral dependence of the absorption coefficient (α) measurements and the analysis near the fundamental absorption edge showed two direct allowed transition with energy gaps of 1.18 and 2.53 eV. Dark current-voltage and capacitance-voltage characteristics of [Ni(Phth)(Me4en)(H2O)2]·4H2O/n-Si heterojunctions were studied to extract the main important parameters of the heterojunction device. The electrical characteristics of the heterojunction device under illumination hold the suitability of the device for optoelectronic applications.

  16. Electronic structure of four-coordinate C3v nickel(II) scorpionate complexes: investigation by high-frequency and -field electron paramagnetic resonance and electronic absorption spectroscopies.

    PubMed

    Desrochers, Patrick J; Telser, Joshua; Zvyagin, S A; Ozarowski, Andrew; Krzystek, J; Vicic, David A

    2006-10-30

    A series of complexes of formula TpNiX, where Tp*- = hydrotris(3,5-dimethylpyrazole)borate and X = Cl, Br, I, has been characterized by electronic absorption spectroscopy in the visible and near-infrared (NIR) region and by high-frequency and -field electron paramagnetic resonance (HFEPR) spectroscopy. The crystal structure of TpNiCl has been previously reported; that for TpNiBr is given here: space group = Pmc2(1), a = 13.209(2) A, b = 8.082(2) A, c = 17.639(4) A, alpha = beta = gamma = 90 degrees , Z = 4. TpNiX contains a four-coordinate nickel(II) ion (3d8) with approximate C3v point group symmetry about the metal and a resulting S = 1 high-spin ground state. As a consequence of sizable zero-field splitting (zfs), TpNiX complexes are "EPR silent" with use of conventional EPR; however, HFEPR allows observation of multiple transitions. Analysis of the resonance field versus the frequency dependence of these transitions allows extraction of the full set of spin Hamiltonian parameters. The axial zfs parameter for TpNiX displays pronounced halogen contributions down the series: D = +3.93(2), -11.43(3), -22.81(1) cm(-1), for X = Cl, Br, I, respectively. The magnitude and change in sign of D observed for TpNiX reflects the increasing bromine and iodine spin-orbit contributions facilitated by strong covalent interactions with nickel(II). These spin Hamiltonian parameters are combined with estimates of 3d energy levels based on the visible-NIR spectra to yield ligand-field parameters for these complexes following the angular overlap model (AOM). This description of electronic structure and bonding in a pseudotetrahedral nickel(II) complex can enhance the understanding of similar sites in metalloproteins, both native nickel enzymes and nickel-substituted zinc enzymes. PMID:17054352

  17. Norfloxacin and N-Donor Mixed-Ligand Copper(II) Complexes: Synthesis, Albumin Interaction, and Anti-Trypanosoma cruzi Activity

    PubMed Central

    Martins, Darliane A.; Gouvea, Ligiane R.; Muniz, Gabriel S. Vignoli; Louro, Sonia R. W.; Batista, Denise da Gama Jaen; Soeiro, Maria de Nazaré C.; Teixeira, Letícia R.

    2016-01-01

    Copper(II) complexes with the first-generation quinolone antibacterial agent norfloxacin containing a nitrogen donor heterocyclic ligand 2,2′-bipyridine (bipy) or 1,10-phenanthroline (phen) were prepared and characterized by IR, EPR spectra, molar conductivity, and elemental analyses. The experimental data suggest that norfloxacin was coordinated to copper(II) through the carboxylato and ketone oxygen atoms. The interaction of the copper(II) complexes with bovine serum albumin (BSA) and human serum albumin (HSA) was investigated using fluorescence quenching of the tryptophan residues and copper(II) EPR spectroscopy. The results of fluorescence titration revealed that copper(II) complexes have a moderate ability to quench the intrinsic fluorescence of the albumins through a static quenching mechanism. EPR experiments showed that BSA and HSA Cu(II) sites compete with NOR for Cu(II)-bipy and Cu(II)-phen to form protein mixed-ligand complexes. Copper(II) complexes, together with the corresponding ligands, were evaluated for their trypanocidal activity in vitro against Trypanosoma cruzi, the causative agent of Chagas disease. The tests performed using bloodstream trypomastigotes showed that the Cu(II)-N-donor precursors and the metal complexes were more active than the free fluoroquinolone. PMID:26924953

  18. Biological Role of Anions (Sulfate, Nitrate , Oxalate and Acetate) on the Antibacterial Properties of Cobalt (II) and Nickel(II) Complexes With Pyrazinedicarboxaimide Derived, Furanyl and Thienyl Compounds.

    PubMed

    Chohan, Z H; Praveen, M

    1999-01-01

    A number of biologically active complexes of cobalt(II) and nickel(II) with pyrazinedicarboxaimido derived thienyl and furanyl compounds having the same metal ion but different anions such as sulphate, nitrate, oxalate and acetate have been synthesized and characterized on the basis of their physical, spectral and analytical data. In order to evaluate the role of anions on their antibacterial properties, these ligands and their synthesized metal complexes with various anions have been screened against bacterial species Escherichia coil,Pseudomonas aeruginosa and Staphylococcus aureus. The title studies have proved a definitive role of anions in increasing the antibacterial properties. PMID:18475887

  19. Biological Role of Anions (Sulfate, Nitrate , Oxalate and Acetate) on the Antibacterial Properties of Cobalt (II) and Nickel(II) Complexes With Pyrazinedicarboxaimide Derived, Furanyl and Thienyl Compounds

    PubMed Central

    Praveen, M.

    1999-01-01

    A number of biologically active complexes of cobalt(II) and nickel(II) with pyrazinedicarboxaimido derived thienyl and furanyl compounds having the same metal ion but different anions such as sulphate, nitrate, oxalate and acetate have been synthesized and characterized on the basis of their physical, spectral and analytical data. In order to evaluate the role of anions on their antibacterial properties, these ligands and their synthesized metal complexes with various anions have been screened against bacterial species Escherichia coil,Pseudomonas aeruginosa and Staphylococcus aureus. The title studies have proved a definitive role of anions in increasing the antibacterial properties. PMID:18475887

  20. Potentiometric and Blood Plasma Simulation Studies of Nickel(II) Complexes of Poly(amino)amido Pentadentate Ligands: Computer Aided Metal-Based Drug Design

    PubMed Central

    Jackson, Graham E.

    2014-01-01

    The thermodynamic equilibria of nickel(II) with N,N′-di(aminoethylene)-2,6-pyridinedicarbonylamine (L1), Bis-(N,N-dimethylethyl)-2,6-pyridinedicarboxamide (L2), and N,N′-bis[2(2-pyridyl)-methyl]pyridine-2,6-dicarboxamide (L3) have been studied at 25°C and an ionic strength of 0.15 mol dm−3 by glass electrode potentiometry. The protonation and formation constants added to blood plasma model predict that Cu(II) competes effectively against Ni(II), Zn(II), and Ca(II) for these ligands in vivo. PMID:25371660

  1. Reversed-phase high-performance liquid chromatography of the stereoisomers of some sweetener peptides with a helical nickel(II) chelate in the mobile phase.

    PubMed

    Bazylak, G

    1994-05-13

    The use of a chiral mobile phase additive in the form of the helically distorted, square-planar, chiral nickel(II) chelate dl-[4,4'-(1-methyl-2-propylethane-1,2-diyldiimino)bis(pent-3 -en-2- onato)]nickel(II) was investigated for the resolution of optical isomers of dipeptide-type sweeteners, viz., aspartame, alitame and antiaspartame, and some of their decomposition products, e.g., diketopiperazines. The chiral discrimination mechanism for the solutes was elucidated. The proposed chiral RP-HPLC system was applied to the stereoselective determination of aspartame impurities in samples of its commercial dietetic and pharmaceutical formulations. PMID:8032495

  2. Bimetallic Gold(I)/Chiral N,N'-Dioxide Nickel(II) Asymmetric Relay Catalysis: Chemo- and Enantioselective Synthesis of Spiroketals and Spiroaminals.

    PubMed

    Li, Jun; Lin, Lili; Hu, Bowen; Lian, Xiangjin; Wang, Gang; Liu, Xiaohua; Feng, Xiaoming

    2016-05-10

    A highly efficient asymmetric cascade reaction between keto esters and alkynyl alcohols and amides is reported. The success of the reaction was attributed to the combination of chiral Lewis acid N,N'-dioxide nickel(II) catalysis with achiral π-acid gold(I) catalysis working as an asymmetric relay catalytic system. The corresponding spiroketals and spiroaminals were synthesized in up to 99 % yield, 19:1 d.r., and more than 99 % ee under mild reaction conditions. Control experiments suggest that the N,N'-dioxide ligand was essential for the formation of the spiro products. PMID:27062196

  3. Theoretical investigation, biological evaluation and VEGFR2 kinase studies of metal(II) complexes derived from hydrotris(methimazolyl)borate.

    PubMed

    Jayakumar, S; Mahendiran, D; Srinivasan, T; Mohanraj, G; Kalilur Rahiman, A

    2016-02-01

    The reaction of soft tripodal scorpionate ligand, sodium hydrotris(methimazolyl)borate with M(ClO4)2·6H2O [MMn(II), Ni(II), Cu(II) or Zn(II)] in methanol leads to the cleavage of B-N bond followed by the formation of complexes of the type [M(MeimzH)4](ClO4)2·H2O (1-4), where MeimzH=methimazole. All the complexes were fully characterized by spectro-analytical techniques. The molecular structure of the zinc(II) complex (4) was determined by X-ray crystallography, which supports the observed deboronation reaction in the scorpionate ligand with tetrahedral geometry around zinc(II) ion. The electronic spectra of complexes suggested tetrahedral geometry for manganese(II) and nickel(II) complexes, and square-planar geometry for copper(II) complex. Frontier molecular orbital analysis (HOMO-LUMO) was carried out by B3LYP/6-31G(d) to understand the charge transfer occurring in the molecules. All the complexes exhibit significant antimicrobial activity against Gram (-ve) and Gram (+ve) bacterial as well as fungal strains, which are quite comparable to standard drugs streptomycin and clotrimazole. The copper(II) complex (3) showed excellent free radical scavenging activity against DPPH in all concentration with IC50 value of 30μg/mL, when compared to the other complexes. In the molecular docking studies, all the complexes showed hydrophobic, π-π and hydrogen bonding interactions with BSA. The cytotoxic activity of the complexes against human hepatocellular liver carcinoma (HepG2) cells was assessed by MTT assay, which showed exponential responses toward increasing concentration of complexes. PMID:26735002

  4. Mechano-switchable, luminescent gels derived from salts of a long-chained, fatty-acid gelator.

    PubMed

    Zhang, Mohan; Weiss, Richard G

    2016-07-27

    Stimulus-responsive molecular gel systems, based on metal salts of a luminescent gelator, 9,10-dioxooctadecanoic acid (DODA), are reported. These salts are structurally the simplest metallo-gelators of which we are aware that exhibit controllable mechano-responsive and luminescent properties. Aggregation is more favored by the metal salts than for DODA itself. However, gelation ability differs dramatically depending on the metal ion: whereas the salts with zinc(ii) and calcium(ii) are inefficient gelators, those with nickel(ii) and copper(ii) can gelate various aromatic liquids, alkanes, and long-chained alcohols. Unlike the DODA gels, no aggregation-induced shift in the positions of the emission spectra of the metal salts could be observed as the sols were transformed to their gel phases. Gels of both nickel(ii) and copper(ii) salts in benzonitrile are among the few known examples with crystalline networks and exhibiting thixotropic behavior. However, there are significant differences in their abilities to recover the initial viscoelastic properties. Structural data for the solid and gel states lead us to conclude that differences among the gelating abilities can be attributed principally to the specific nature of interactions of the salts at their head groups. They appear to control the mechanical and emissive properties of the gels as well as whether the initial aggregation of the salts in the sol phases will support the growth of 1D objects that are capable of maintaining strong contacts, leading to 3D networks and gel formation. Overall, the results provide a facile strategy for the design of luminescent materials with controllable mechano-responsiveness by modifying the metal ions within fibrillar assemblies. PMID:27400800

  5. Thermodynamics of the formation of copper(II) complexes with L-histidine in aqueous solution

    NASA Astrophysics Data System (ADS)

    Gorboletova, G. G.; Metlin, A. A.

    2015-02-01

    The heat effects from the reaction between L-histidine solutions and Cu(NO3)2 solutions at 298.15 K in the 0.2 to 1.0 (KNO3) range of ionic strength are measured by means of direct calorimetry. The experimental data is treated with allowance for the simultaneous proceeding of several processes. The heat effects of the formation of complexes Cu(His)+, Cu(His)2, CuHHis2+, CuH(His){2/+} and CuH2(His){2/2+} are calculated from calorimetric measurements. The standard enthalpies of formation for complexes of L-histidine with Cu2+ ions are obtained via extrapolation to zero ionic strength. The relationship between the thermodynamic characteristics of the formation of complexes of copper(II) with L-histidine and their structure is determined.

  6. Electrical conductivity of solutions of copper(II) nitrate crystalohydrate in dimethyl sulfoxide

    NASA Astrophysics Data System (ADS)

    Mamyrbekova, Aigul K.; Mamitova, A. D.; Mamyrbekova, Aizhan K.

    2016-06-01

    Conductometry is used to investigate the electric conductivity of Cu(NO3)2 ṡ 3H2O solutions in dimethyl sulfoxide in the 0.01-2.82 M range of concentrations and at temperatures of 288-318 K. The limiting molar conductivity of the electrolyte and the mobility of Cu2+ and NO 3 - ions, the effective coefficients of diffusion of copper(II) ions and nitrate ions, and the degree and constant of electrolytic dissociation are calculated for different temperatures from the experimental results. It is established that solutions containing 0.1-0.6 M copper nitrate trihydrate in DMSO having low viscosity and high electrical conductivity can be used in electrochemical deposition.

  7. Catalytic wet oxidation of thiocyanate with homogeneous copper(II) sulphate catalyst.

    PubMed

    Collado, Sergio; Laca, Adriana; Díaz, Mario

    2010-05-15

    The wet oxidation of thiocyanate has been investigated in a semi-batch reactor at temperatures between 423 and 473 K and pressures between 6.1 x 10(3) and 1.0 x 10(4)kPa in the presence of copper(II) sulphate as catalyst. The effects of copper concentration, initial thiocyanate concentration, pressure and temperature on the reaction rate were analyzed and the main products of reaction were identified. A kinetic model for the Cu-catalyzed reaction is here proposed, including temperature, oxygen concentration, and the reduction of Cu(2+) to Cu(+) that gives an accurate prediction of the oxidation process under the assayed conditions. A mechanistic model based on the formation of a transition complex between a copper cation and two thiocyanate anions has been proposed for the catalytic wet oxidation. PMID:20045245

  8. Monitoring cellular uptake and cytotoxicity of copper(II) complex using a fluorescent anthracene thiosemicarbazone ligand.

    PubMed

    Kate, Anup N; Kumbhar, Anupa A; Khan, Ayesha A; Joshi, Pranaya V; Puranik, Vedavati G

    2014-01-15

    The thiosemicarbazone derivative of anthracene (ATSC, anthracene thiosemicarbazone 1) and its copper(II) complex (CuATSC, 2) were synthesized and characterized by spectroscopic, electrochemical, and crystallographic techniques. Interaction of 1 and 2 with calf thymus (CT) DNA was explored using absorption and emission spectral methods, and viscosity measurements reveal a partial-intercalation binding mode. Their protein binding ability was monitored by the quenching of tryptophan emission using bovine serum albumin (BSA) as a model protein. Furthermore, their cellular uptake, in vitro cytotoxicity testing on the HeLa cell line, and flow cytometric analysis were carried out to ascertain the mode of cell death. Cell cycle analysis indicated that 1 and 2 cause cell cycle arrest in sub-G1 phase. PMID:24328322

  9. A Hexameric Cationic Copper(II) Metallacrown as a Pertechnetate and Perrhenate Scavenger.

    PubMed

    Rodríguez-Hermida, Sabina; Lago, Ana Belén; Pino-Cuevas, Arantxa; Hagenbach, Adelheid; Cañadillas-Delgado, Laura; Carballo, Rosa; Abram, Ulrich; Vázquez-López, Ezequiel M

    2016-01-26

    Materials based on the cationic copper(II) hexanuclear 18-membered metallacrown [18-MCCuII-N(2ph)-6](6+) (2phH=2-piconyl hydrazide) and tetrafluoroborate, perchlorate, nitrate, sulfate, and perrhenate anions were prepared by an easy method in aqueous medium. Single-crystal X-ray characterization of six members of this new family of complexes showed that the anions are attached to the metallacrown by direct coordination to a copper cation or by hydrogen-bonding interaction with the center of the hexamer. The stable cationic nature of the complexes and their ability to bind different anions allows them to adsorb and immobilize environmentally relevant anions such as MO4(-) (M=Tc, Re). The MO4(-) trapping capacities suggest that these materials would be useful in the treatment of oxoanionic contaminants in water. PMID:26671639

  10. Reconstitution of Formylglycine-generating Enzyme with Copper(II) for Aldehyde Tag Conversion.

    PubMed

    Holder, Patrick G; Jones, Lesley C; Drake, Penelope M; Barfield, Robyn M; Bañas, Stefanie; de Hart, Gregory W; Baker, Jeanne; Rabuka, David

    2015-06-19

    To further our aim of synthesizing aldehyde-tagged proteins for research and biotechnology applications, we developed methods for recombinant production of aerobic formylglycine-generating enzyme (FGE) in good yield. We then optimized the FGE biocatalytic reaction conditions for conversion of cysteine to formylglycine in aldehyde tags on intact monoclonal antibodies. During the development of these conditions, we discovered that pretreating FGE with copper(II) is required for high turnover rates and yields. After further investigation, we confirmed that both aerobic prokaryotic (Streptomyces coelicolor) and eukaryotic (Homo sapiens) FGEs contain a copper cofactor. The complete kinetic parameters for both forms of FGE are described, along with a proposed mechanism for FGE catalysis that accounts for the copper-dependent activity. PMID:25931126

  11. A novel copper(II) coordination polymer with carboxylate and isoindol backbones of a bifunctional ligand

    NASA Astrophysics Data System (ADS)

    Patra, Ayan; Sen, Tamal K.; Musie, Ghezai T.; Mandal, Swadhin K.; Bera, Manindranath

    2013-09-01

    The reaction of a bifunctional ligand, 3-(1-oxo-1,3-dihydro-isoindol-2-yl)-propionic acid (Hpda) with Cu(NO3)2ṡ3H2O in methanol-water in the presence of NaOH at room temperature produces a novel dinuclear copper(II) coordination polymer [Cu2(pda)4]n. The complex is fully characterized in the solid state as well as in solution using various analytical techniques including single crystal X-ray diffraction study. The single crystal X-ray structure analysis reveals that the monomeric unit of complex consists of Cu2(O2CR)4 paddlewheel building unit, where the two copper centers acquire a distorted square pyramidal geometry with amide oxygen of the isoindol ring of an adjacent Hpda ligand sitting on the axial positions.

  12. Synthesis, characterization and catalytic activities towards epoxidation of olefins of dinuclear copper(II) complexes

    NASA Astrophysics Data System (ADS)

    Halder, Shibashis; Mukherjee, Aparajita; Ghosh, Koushik; Dey, Sudipto; Nandi, Mahasweta; Roy, Partha

    2015-12-01

    Two copper(II) complexes, [Cu2(L1)Cl3].2H2O (1) and [Cu2(L2)(N3)Cl2] (2) where HL1 = 4-methyl-2,6-bis((2-morpholinoethylimino)methyl)phenol and HL2 = 4-methyl-2,6-bis((3-morpholinopropylimino)methyl)phenol have been synthesized and characterized by elemental analysis, various spectroscopic methods, TGA and single crystal X-ray diffraction analysis. Single crystal X-ray diffraction analysis reveals that in both the complexes, two copper atoms are linked by phenoxo oxygen atom and a bridging ligand, namely chloride and azide, respectively. These complexes have been used as catalyst for the epoxidation of cyclohexene, styrene, α-methyl styrene, trans-stilbene and norbornene using tert-butyl hydroperoxide as the oxidant in acetonitrile under mild conditions. All of the substrates undergo conversion to produce respective epoxide as the major product.

  13. Characterization and biological activities of two copper(II) complexes with dipropylenetriamine and diamine as ligands

    NASA Astrophysics Data System (ADS)

    AL-Noaimi, Mousa; Choudhary, Mohammad I.; Awwadi, Firas F.; Talib, Wamidh H.; Hadda, Taibi Ben; Yousuf, Sammer; Sawafta, Ashraf; Warad, Ismail

    2014-06-01

    Two new mixed-ligand copper(II) complexes, [Cu(dipn)(Nsbnd N)]Br2(1-2) [dipn = dipropylenetriamine, Nsbnd N = ethylenediamine (en) (1) and propylenediamine (pn) (2)], have been synthesized. These complexes were characterized by spectroscopic and thermal techniques. Crystal structure for 2 shows a distorted trigonal-bipyramidal geometry around Cu(II) ion with one solvate water molecule. Antimicrobial and antiproliferative assays were conducted to evaluate the biological activities of these complexes. The complexes exhibit a promising antimicrobial effect against an array of microbes at 200 μg/mL concentration. The antiproliferative assay shows a high potential of these complexes to target Human keratinocyte cell line with IC50 values of 155 and 152 μM. The absorption spectrum of 2 in water was modeled by time-dependent density functional theory (TD-DFT).

  14. Antimalarial, antimicrobial, cytotoxic, DNA interaction and SOD like activities of tetrahedral copper(II) complexes.

    PubMed

    Mehta, Jugal V; Gajera, Sanjay B; Patel, Mohan N

    2014-11-01

    The mononuclear copper(II) complexes with P, O-donor ligand and different fluoroquinolones have been synthesized and characterized by elemental analysis, electronic spectra, TGA, EPR, FT-IR and LC-MS spectroscopy. An antimicrobial efficiency of the complexes has been tested against five different microorganisms in terms of minimum inhibitory concentration (MIC) and displays very good antimicrobial activity. The binding strength and binding mode of the complexes with Herring Sperm DNA (HS DNA) have been investigated by absorption titration and viscosity measurement studies. The studies suggest the classical intercalative mode of DNA binding. Gel electrophoresis assay determines the ability of the complexes to cleave the supercoiled form of pUC19 DNA. Synthesized complexes have been tested for their SOD mimic activity using nonenzymatic NBT/NADH/PMS system and found to have good antioxidant activity. All the complexes show good cytotoxic and in vitro antimalarial activities. PMID:25467683

  15. Synthesis of four binuclear copper(II) complexes: Structure, anticancer properties and anticancer mechanism.

    PubMed

    Qi, Jinxu; Liang, Shichu; Gou, Yi; Zhang, Zhenlei; Zhou, Zuping; Yang, Feng; Liang, Hong

    2015-01-01

    Copper (Cu) compounds are a promising candidate for next generation metal anticancer drugs and have been extensively studied. Therefore, four binuclear copper(II) compounds derived from Schiff base thiosemicarbazones (L1-L4), namely [CuCl(L1)]2 (C1), [CuNO3(L2)]2 (C2), [Cu(NCS) (L3)]2 (C3) and [Cu(CH3COO) (L4)]2 (C4) were synthesized and characterized. Four of these compounds showed very high cytotoxicity to cancer cell lines in vitro. These Cu(II) compounds strongly promoted the apoptosis of BEL-7404 cells. The formation of reactive oxygen species (ROS), change in mitochondrial membrane potential and western blot analysis revealed that Cu compounds could induce cancer cell apoptosis through the intrinsic ROS-mediated mitochondrial pathway accompanied by the regulation of Bcl-2 family proteins. PMID:25899339

  16. Reconstitution of Formylglycine-generating Enzyme with Copper(II) for Aldehyde Tag Conversion

    PubMed Central

    Holder, Patrick G.; Jones, Lesley C.; Drake, Penelope M.; Barfield, Robyn M.; Bañas, Stefanie; de Hart, Gregory W.; Baker, Jeanne; Rabuka, David

    2015-01-01

    To further our aim of synthesizing aldehyde-tagged proteins for research and biotechnology applications, we developed methods for recombinant production of aerobic formylglycine-generating enzyme (FGE) in good yield. We then optimized the FGE biocatalytic reaction conditions for conversion of cysteine to formylglycine in aldehyde tags on intact monoclonal antibodies. During the development of these conditions, we discovered that pretreating FGE with copper(II) is required for high turnover rates and yields. After further investigation, we confirmed that both aerobic prokaryotic (Streptomyces coelicolor) and eukaryotic (Homo sapiens) FGEs contain a copper cofactor. The complete kinetic parameters for both forms of FGE are described, along with a proposed mechanism for FGE catalysis that accounts for the copper-dependent activity. PMID:25931126

  17. Antimalarial, antimicrobial, cytotoxic, DNA interaction and SOD like activities of tetrahedral copper(II) complexes

    NASA Astrophysics Data System (ADS)

    Mehta, Jugal V.; Gajera, Sanjay B.; Patel, Mohan N.

    2015-02-01

    The mononuclear copper(II) complexes with P, O-donor ligand and different fluoroquinolones have been synthesized and characterized by elemental analysis, electronic spectra, TGA, EPR, FT-IR and LC-MS spectroscopy. An antimicrobial efficiency of the complexes has been tested against five different microorganisms in terms of minimum inhibitory concentration (MIC) and displays very good antimicrobial activity. The binding strength and binding mode of the complexes with Herring Sperm DNA (HS DNA) have been investigated by absorption titration and viscosity measurement studies. The studies suggest the classical intercalative mode of DNA binding. Gel electrophoresis assay determines the ability of the complexes to cleave the supercoiled form of pUC19 DNA. Synthesized complexes have been tested for their SOD mimic activity using nonenzymatic NBT/NADH/PMS system and found to have good antioxidant activity. All the complexes show good cytotoxic and in vitro antimalarial activities.

  18. A terminal nickel(II) anilide complex featuring an unsymmetrically substituted amido pincer ligand: synthesis and reactivity.

    PubMed

    Liang, Lan-Chang; Li, Chun-Wei; Lee, Pei-Ying; Chang, Chih-Hsiang; Lee, Hon Man

    2011-09-21

    This work describes preparation and reaction chemistry of a terminal nickel(II) anilide complex supported by an unsymmetrically substituted diarylamido diphosphine ligand, [N(o-C(6)H(4)PPh(2))(o-C(6)H(4)P(i)Pr(2))](-) ([Ph-PNP-(i)Pr](-)). Treatment of NiCl(2)(DME) with H[Ph-PNP-(i)Pr] in THF at room temperature produced [Ph-PNP-(i)Pr]NiCl as green crystals in 82% yield. Salt metathesis of [Ph-PNP-(i)Pr]NiCl with LiNHPh(THF) in THF at -35 °C generated cleanly [Ph-PNP-(i)Pr]NiNHPh as a greenish blue solid. The anilide complex deprotonates protic (e.g., PhOH and PhSH) and aprotic (e.g., trimethylsilylacetylene, phenylacetylene, and acetonitrile) acids in benzene at room temperature to give quantitatively [Ph-PNP-(i)Pr]NiX (X = OPh, SPh, C≡CSiMe(3), C≡CPh, CH(2)CN). In addition, [Ph-PNP-(i)Pr]NiNHPh also behaves as a nucleophile to react with acetyl chloride to yield [Ph-PNP-(i)Pr]NiCl and N-phenylacetamide quantitatively. Carbonylation of [Ph-PNP-(i)Pr]NiNHPh with carbon monoxide affords cleanly the carbamoyl derivative [Ph-PNP-(i)Pr]Ni[C(O)NHPh]. The relative bond strengths of Ni-E in [Ph-PNP-(i)Pr]NiEPh (E = NH, O, S, C≡C) are assessed and discussed. PMID:21666917

  19. Homogeneous hydrogenation and isomerization of 1-octene catalyzed by nickel(II) complexes with bidentate diarylphosphane ligands.

    PubMed

    Mooibroek, Tiddo J; Wenker, Erica C M; Smit, Wietse; Mutikainen, Ilpo; Lutz, Martin; Bouwman, Elisabeth

    2013-07-15

    A systematic library of 24 nickel(II) complexes with bidentate diphosphane ligands was synthesized, and the solid-state structures of five of them were determined with X-ray crystallography. The compounds C1-C3 are common P2Ni(II)X2-type complexes, while C4 contains a unique [P2Ni(II)(NH3)(OAc)](+) square-planar structure with a P2NO donor set and C5 constitutes a rare [(P2Ni(II))2(μ-OH)2](2+) dinuclear compound. The catalytic activity of all complexes was tested in the hydrogenation and/or isomerization of 1-octene in a CH2Cl2/CH3OH reaction medium. Catalyst precursors bearing ligands with o-alkoxy aryl rings selectively hydrogentate 1-octene to n-octane, while catalytic systems comprising ligands without the o-alkoxy functionality selectively isomerize the substrate to a mixture of internal alkenes, mostly cis- and trans-2-octene. The conversion is enhanced by equipping the ligand aryl rings with electron-donating alkoxy groups, by increasing the steric bulk of the backbone and/or the aryl rings, by employing relatively noncoordinating anions, and by adding a base as the cocatalyst. Using the compound [Ni(L3X)I2] as the catalyst precursor and upon application of standard hydrogenation conditions, full conversion of the substrate was achieved in 1 h to isomerization products only (TON = 1940). When a catalytic amount of the base is added, a similar result is obtained even in the absence of H2. A maximum TON of 4500 in 1 h with 96% selectivity for n-octane was achieved by employing [Ni(oMeO-L3X)(NH3)(OAc)]PF6 as the catalyst precursor. PMID:23822166

  20. Synthesis, antimicrobial, DNA-binding and photonuclease studies of cobalt(III) and nickel(II) Schiff base complexes.

    PubMed

    Sangeetha Gowda, K R; Bhojya Naik, H S; Vinay Kumar, B; Sudhamani, C N; Sudeep, H V; Ravikumar Naik, T R; Krishnamurthy, G

    2013-03-15

    New metal complexes of the type [M(nih)(L)](PF(6))(n)·xH(2)O and [M(nih)(2)](PF(6))·xH(2)O (where M=Co(III) or Ni(II), L=1,10-phenanthroline (phen)/or 2,2' bipyridine (bpy), nih=2-hydroxy-1-naphthaldehyde isonicotinoyl hydrazone, n=2 or 1 and x=3 or 2) have been synthesized and characterized by elemental analysis, magnetic, IR and (1)H NMR spectral data. The electronic and magnetic moment 2.97-3.07 B.M. data infers octahedral geometry for all the complexes. The IR data reveals that Schiff base (nih) form coordination bond with the metal ion through azomethine-nitrogen, phenolic-oxygen and carbonyl-oxygen in a tridentate fashion. In addition, DNA-binding properties of these six metal complexes were investigated using absorption spectroscopy, viscosity measurements and thermal denaturation methods. The results indicated that the nickel(II) complex strongly bind with calf-thymus DNA with intrinsic DNA binding constant K(b) value of 4.9×10(4) M(-1) for (3), 4.2×10(4) M(-1) for (4), presumably via an intercalation mechanism compared to cobalt(III) complex with K(b) value of 4.6×10(4) M(-1) (1) and 4.1×10(4) M(-1) (2). The DNA Photoclevage experiment shows that, the complexes act as effective DNA cleavage agent. PMID:23314217

  1. Spectroscopic studies on polymeric cobalt(II) and nickel(II) complexes with bridging succinonitrile and succinonitrile isotopomer ligands

    NASA Astrophysics Data System (ADS)

    Fengler, O. I.; Ruoff, A.

    2002-02-01

    A series of cobalt(II) and nickel(II) complexes were synthesized using succinonitrile and its [1,4- 13C 2]-, [ 15N 2]-, [2,2,3,3- 2H 4]- and [1,4- 13C 2-2,2,3,3- 2H 4]- isotopomers as bridging ligands. Spectroscopic studies, as well as X-ray powder diffraction profiles, were used to identify the nature of the octahedral coordination sphere of the central metal ions and to assign the vibrational spectra in full detail. The succinonitrile ligands were found to be in trans configuration in all the complexes studied and to be coordinated via the lone pairs of their nitrile nitrogens. The rule of mutual exclusion was found to be fulfilled for the succinonitrile ligands under the Ci symmetry of the complexes and the vibrations of the succinonitrile ligands were found to appear in either the infrared or the Raman spectra. All succinonitrile isotopomers exhibited blue-shifts of 43-71 cm -1 upon coordination, while most of the other vibrations remained unchanged or underwent small shifts of only a few wavenumbers. The mass differences of the succinonitrile isotopomers were found to shift mainly the vibrations of the respective affected part of the molecules in comparison with the normal succinonitrile. The exchange of the halides, which are coordinated to the central metal ion, was also found to influence the vibrations of the associated water molecules and we could identify vibrational bands arising due to the H-bond interaction between the halides and the water molecules. Finally, we showed that all complexes under consideration have, spectroscopically, the same symmetry.

  2. Spectroscopic studies on polymeric cobalt(II) and nickel(II) complexes with bridging succinonitrile and succinonitrile isotopomer ligands.

    PubMed

    Fengler, I O; Ruoff, A

    2002-02-01

    A series of cobalt(II) and nickel(II) complexes were synthesized using succinonitrile and its [1,4-13C2], [15N2]-, [2,2,3,3-2H4]- and [1,4-13C,-2,2,3,3-2H4]- isotopomers as bridging ligands. Spectroscopic studies, as well as X-ray powder diffraction profiles, were used to identify the nature of the octahedral coordination sphere of the central metal ions and to assign the vibrational spectra in full detail. The succinonitrile ligands were found to be in trans configuration in all the complexes studied and to be coordinated via the lone pairs of their nitrile nitrogens. The rule of mutual exclusion was found to be fulfilled for the succinonitrile ligands under the Ci symmetry of the complexes and the vibrations of the succinonitrile ligands were found to appear in either the infrared or the Raman spectra. All succinonitrile isotopomers exhibited blue-shifts of 43-71 cm(-1) upon coordination, while most of the other vibrations remained unchanged or underwent small shifts of only a few wavenumbers. The mass differences of the succinonitrile isotopomers were found to shift mainly the vibrations of the respective affected part of the molecules in comparison with the normal succinonitrile. The exchange of the halides, which are coordinated to the central metal ion, was also found to influence the vibrations of the associated water molecules and we could identify vibrational bands arising due to the H-bond interaction between the halides and the water molecules. Finally, we showed that all complexes under consideration have, spectroscopically, the same symmetry. PMID:11905542

  3. Synthesis, spectral characterization, molecular modeling and antimicrobial activity studies on 2-aminopyridine-cyclodiphosph(V)azane derivative and its homo-binuclear zinc(II) complexes

    NASA Astrophysics Data System (ADS)

    Alaghaz, Abdel-Nasser M. A.

    2014-06-01

    Complexes of zinc(II) of general composition [Zn2(L)X2(H2O)4]nH2O have been synthesized [L = 1,3-dipyridyl-2,4-dioxo-2‧,4‧-bis(2-iminopyridine)cyclodi-phosph(V)azane and X = NO3-; n = 2, OAc-; n = 1, SO42-; n = 2 and Cl-; n = 2]. The elemental analysis, molar conductance measurements, mass, IR, UV, NMR (1H and 31P), TGA, DTA, SEM and XRD spectral studies of the compounds led to the conclusion that the cyclodiphosph(V)azane ligand (H2L) acts as a bidentate manner per zinc ion. The cyclodiphosph(V)azane ligand forms hexa-coordinated complexes having octahedral geometry for Zn(II) complexes. The elemental analyses and mass spectral data have justified the [Zn2(L)X2(H2O)4]nH2O composition of complexes. Infrared spectra of the zinc complexes indicate deprotonation and coordination of the imine NH. It also confirms that nitrogen atoms of the pyridine group contribute to the complexation. The X-ray powder diffraction (XRD) was performed of [Zn2L(SO4)2(H2O)4]2H2O complex. The XRD patterns indicate crystalline nature for the [Zn2L(SO4)2(H2O)4]2H2O complex. The measured low molar conductance values in dimethylformamide indicate that the complexes are non-electrolyte nature. The surface morphology (SEM) of the cyclodiphosph(V)azane ligand and the [Zn2L(NO3)2(H2O)4]2H2O complex were studied by SEM. The thermal studies suggested that the complexes are more stable as compared to ligand. In molecular modeling the geometries of cyclodiphosph(V)azane ligand H2L and its zinc(II) complexes were fully optimized with respect to the energy using the 6-31G basis set. The cyclodiphosph(V)azane ligand and the zinc(II) complexes have been measured in vitro to judge their antibacterial (Escherichia coli and Staphylococcus aureus) and antifungal (Aspergillus niger and Pencillium chrysogenum) activities.

  4. Synthesis, crystal structures and luminescent properties of zinc(II) metal-organic frameworks constructed from terpyridyl derivative ligand

    NASA Astrophysics Data System (ADS)

    Yang, Xiao-Le; Shangguan, Yi-Qing; Hu, Huai-Ming; Xu, Bing; Wang, Bao-Cheng; Xie, Juan; Yuan, Fei; Yang, Meng-Lin; Dong, Fa-Xin; Xue, Gang-Lin

    2014-08-01

    Five zinc(II) metal-organic frameworks, [Zn3(344-pytpy)2Cl6]n·n(H2O) (1), [Zn(344-pytpy)(ox)]n (2), [Zn2(344-pytpy)(bdc)2]n·1.5n(H2O) (3), [Zn2(344-pytpy)2 (sfdb)2]n·1.5n(H2O) (4) and [Zn3(344-pytpy)2(btc)2]n·2n(H2O) (5), (344-pytpy=4‧-(3-pyridyl)-4,2‧:6‧,4″-terpyridine, H2ox=oxalic acid, H2bdc=1,4-benzenedi-carboxylic acid, H2sfdb=4,4‧-sulfonyldibenzoic acid and H3btc=1,3,5-benzene-tricarboxylic acid) have been prepared by hydrothermal reactions. Compound 1 is a 1D chain structure, in which 344-pytpy ligand links three ZnII centers through three of terminal N-donors. Compound 2 is a 4-connected 3D framework with the dia topological net and the Schläfli symbol of 66. Compound 3 displays a unusual 3-fold interpenetrating 3D coordination network which exhibits a new intriguing (3,3,4)-connected topological net with the Schläfli symbol of (4.82)(4.85)(83). Compound 4 features a two-fold interpenetrating 4-connected 2D framework with the sql topological net and the Schläfli symbol of (44.62). Compound 5 is a new self-interpenetrating (3,3,4,4)-connected topological net with the Schläfli symbol of (6.82)2(62.82.10.12)(62.83.10)2(62.8)2. The luminescence properties of 1-5 have been investigated by emission spectra and they possess great thermal stabilities which can be stable up to around 400 °C.

  5. Application of Colorimetric Solid Phase Extraction (C-SPE) to Monitoring Nickel(II) and Lead(II) in Spacecraft Water Supplies

    NASA Technical Reports Server (NTRS)

    Diaz, Neil C.; Gazda, Daniel B.; Fritz, James S.; Porter, Marc D.; Rutz, Jeff; Mudgett, Paul; Schultz, John

    2004-01-01

    Archived water samples collected on the International Space Station (ISS) and returned to Earth for analysis have, in a few instances, contained trace levels of heavy metals. Building on our previous advances using Colorimetric Solid Phase Extraction (C-SPE) as a biocide monitoring technique, we are devising methods for the low level monitoring of nickel(II), lead(II) and other heavy metals. C-SPE is a sorption-spectrophotometric platform based on the extraction of analytes onto a membrane impregnated with a colorimetric reagent that are then quantified on the surface of the membrane using a diffuse reflectance spectrophotometer. Along these lines, we have determined nickel(II) via complexation with dimethylglyoxime (DMG) and begun to examine the analysis of lead(II) by its reaction with 2,5- dimercapto-1,3,4-thiadiazole (DMTD) and 4-(2- pyridylazo)-resorcinol (PAR). These developments are also extending a new variant of C-SPE in which immobilized reagents are being incorporated into this methodology in order to optimize sample reaction conditions and to introduce the colorimetric reagent. This paper describes the status of our development of these two new methods.

  6. Synthesis, structure and properties of a 3D plywood-like nickel(II) hexaazamacrocyclic coordination polymer constructed from weak Ni\\ctdot O interactions and hydrogen bonding

    NASA Astrophysics Data System (ADS)

    Tao, Bo; Jiang, Xiang; Xia, Hua; Cheng, Hefa

    2012-03-01

    A 3D plywood-like nickel(II) hexaazamacrocyclic coordination polymer {[Ni(hto)(H2btec]}n (2) (hto = 1,3,6,9,11,14-hexaazatricyclo[12.2.1.16,9]octadecane, H4btec = 1,2,4,5-benzenetetracarboxylic acid) was synthesized by a slow diffusion method and characterized by X-ray crystallography and spectroscopic methods. The structure of 2 is made up of [Ni(hto)]2+ cation and H2btec2- anion in a molecular ratio of 1:1. The nickel(II) ions in the complex are bridged by the H2btec2- ligand based on weak Ni⋯O coordination interactions to form a 1D chain. The alternate cross-like 1D chains are packed in a plywood-like structure and interconnected with each other by hydrogen bonding to form a 3D network. Complex 2 exhibits fluorescent emission in the solid state at room temperature.

  7. Covalent functionalization of multi-wall carbon nanotubes (MWNTs) by nickel(II) Schiff-base complex: Synthesis, characterization and liquid phase oxidation of phenol with hydrogen peroxide

    NASA Astrophysics Data System (ADS)

    Salavati-Niasari, Masoud; Bazarganipour, Mehdi

    2008-12-01

    The chemical modification of multi-wall carbon nanotubes (MWNTs) is an emerging area in material science. In the present study, hydroxyl functionalized nickel(II) Schiff-base has been covalently anchored on modified MWNTs. The new modified MWNTs have been characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron (XPS), thermal analysis, UV-vis, diffuse reflectance (DRS), FT-IR spectroscopy and elemental analysis. The results suggest that the symmetrical Schiff-base; N, N'-bis(4-hydroxysalicylidene)-ethylene-1,2-diamine; H 2[(OH) 2-salen]; is a bivalent anion with tetradentate N 2O 2 donors derived from the phenolic oxygen and azomethine nitrogen. The formula was found to be [Ni((OH) 2-salen)] for the 1:1 non-electrolytic complex. Multi-wall carbon nanotubes covalently anchored nickel(II) complex ([Ni((OH) 2-salen)]@MWNTs) catalyze the oxidation of phenol with H 2O 2. Oxidation of phenol catalyzed by this complex gave catechol and hydroquinone as major products. A suitable reaction condition has been optimized for [Ni((OH) 2-salen)]@MWNTs by considering the effect of various parameters such as reaction time and amount of oxidant, different solvents, concentration of substrate, etc. for the maximum transformation of phenol.

  8. The effects of nickel(II) complexes with imidazole derivatives on pyocyanin and pyoverdine production by Pseudomonas aeruginosa strains isolated from cystic fibrosis.

    PubMed

    Gałczyńska, Katarzyna; Kurdziel, Krystyna; Adamus-Białek, Wioletta; Wąsik, Sławomir; Szary, Karol; Drabik, Marcin; Węgierek-Ciuk, Aneta; Lankoff, Anna; Arabski, Michał

    2015-01-01

    Pseudomonas aeruginosa infection is problematic in patients with cystic fibrosis (CF). P. aeruginosa secretes a diversity of pigments, such as pyocyanin and pyoverdine. The aim of this study was to evaluate the effects of complexes of nickel(II) ([Ni(iaa)2(H2O)2]·H2O (iaa = imidazole-4-acetate anion), [Ni(1-allim)6](NO3)2 (1-allim = 1-allylimidazole) and NiCl2 on pyocyanin and pyoverdine production by 23 strains of P. aeruginosa isolated from cystic fibrosis under growth conditions specific for the CF respiratory system. The antibacterial effects and biophysical properties of the tested substances were measured by spectrofluorometric techniques, as well as by laser interferometry, confocal and atomic force microscopy. The cytotoxic properties of all compounds were measured by Annexin/IP assay against A549 cells. All tested compounds have no effect on pyocyanin production and decrease the pyoverdine secretion in about 40% of tested P. aeruginosa strains at non-cytotoxic range of concentrations. Imidazole-4-acetate anion and 1-allylimidazole have good diffusion properties in the mature P. aeruginosa PAO1 biofilm. In conclusion, the tested nickel(II) complexes do not have clinical implications in P. aeruginosa eradication in cystic fibrosis. The diffusion properties of 1-allylimidazole and imidazole-4-acetate and their lack of effect on A549 cells suggest that they might be considered for chemical synthesis with other transition metals. PMID:26645324

  9. X-ray photoelectron spectroscopy of copper(II), copper(I), and mixed valence systems.

    PubMed

    Rupp, H; Weser, U

    1976-01-01

    X-ray photoelectron spectroscopy using copper(II), copper(I) and the mixed valence Cu(II)/Cu(I) compounds was employed as a means of studying electron transfer reactions in copper proteins. The X-ray photoelectron spectra of copper(II) compounds display characteristic satellites of both variable size and resolution. Some of these satellites could be assigned to specific ligand interactions. Unlike electron paramagnetic resonance spectroscopy, the X-ray photoelectron spectroscopic measurements of copper(I) compounds allowed the unequivocal assignment of this oxidation state. No satellites at all could be detected in the Cu(I) spectra. Furthermore, established mixed valence Cu(II)/Cu(I) complexes including Cu2SO3-CuSO3-2H2O and Cu4Cl5 (ethylenediamine)2 proved essentially a mixture of distinct portions of Cu(I) and Cu(II). This indicates that both oxidation states of copper survive in such complexes. In contrast, all Cu X-ray photoelectron signals of the more tentatively described mixed valence complexes Na2Cu3S3 and the mineral covellite, CuI4CuII2(S2)2S2, could be attributed exclusively to Cu(I). In view of the known binding of copper with sulfur in many copper proteins, it was of utmost importance to study the copper-sulfur interactions. We have demonstrated the absence of Cu(II) in CuS. This indicates strong metal-induced polarization of sulfur resulting in electron transfer to copper to yield Cu(I). PMID:953045

  10. Copper(II) interactions with nonsteroidal antiinflammatory agents. I. Salicylic acid and acetylsalicylic acid.

    PubMed

    Brumas, V; Brumas, B; Berthon, G

    1995-02-15

    Recently a growing body of evidence has accumulated on the beneficial effects of copper compounds toward various models of inflammation, and copper complexes of nonsteroidal antiinflammatory drugs (NSAIDs) have been shown to be more effective in this respect than the parent agents. However, the origin of this activity remains unclear: The ability of NSAIDs to influence copper metabolism is still questionable, and apart from the claimed SOD-like activity of copper salts in vivo, relatively little is known about how copper-NSAID interactions may help regulate the inflammatory process. Before the potential role of copper-NSAID complexes versus inflammation can be elucidated, speciation studies are necessary (i) to analyze the overall influence of these drugs on copper metabolism and (ii) to discriminate the individual complexes likely to represent the active form of the drug in vivo. In this paper, copper(II) complex equilibria with salicylic and acetylsalicylic acids--and benzoic acid used as a reference--as well as the mixed-ligand complex equilibria generated by these binary systems and L-histidine [main low-molar-mass ligand of copper(II) in blood plasma] have been investigated under physiological conditions (37 degrees C; 0.15-M NaCl). Confirming previous observations by others, resulting simulated plasma copper distributions virtually rule out any quantitative influence of salicylate on copper tissue diffusion at therapeutic levels. Even though, as is presently shown, both salicylate and acetylsalicylate may favor the gastrointestinal absorption of copper, it seems unlikely that salicylate can exert its antinflammatory activity predominantly through copper complexation. The assertion that copper-NSAID complexes represent the active forms of NSAIDs therefore seems to be of limited significance for salicylate. PMID:7876837

  11. Oxidation of substituted phenols using copper(II) metallatriangles formed through ligand sharing

    NASA Astrophysics Data System (ADS)

    Mahiya, Kuldeep; Kumar, Ravinder; Lloret, Francisco; Mathur, Pavan

    2014-12-01

    Reaction of N2,N2";-bis-[(1-butyl-benzimidazol-2yl)methyl]biphenyl-2,2";-dicarboxamide (L) with CuX2ṡnH2O in methanol leads to the assembly of four trinuclear Cu(II) complexes with the general formula [Cu3(L)3X3]ṡ3XṡnH2OṡmMeCN, where X = Cl-, Br-, NO3- and C6H5COO- and n = 0-5, m = 0-8 (compounds 1-4, respectively). The structure of one of the complex contains three Cu(II) metal ions at the corners of an equilateral triangle. Each of the copper(II) are coordinated through two benzimidazolyl imine N-atoms and two amide carbonyl O-atoms and the apical position is occupied by an anionic nitrate ion, leading to a distorted square pyramidal environment. The magnetic susceptibility data were analyzed through Hamiltonian H = -J (S1S2 + S2S3 + S1S3) obtaining -J = 0.16, 0.12, 0.15 and 0.14 cm-1 for 1-4, respectively. X-Band EPR spectra typically show a broad single line at 120 K with g ∼ 2.11. Oxidation of phenols was studied homogeneously using copper(II) metallatriangles (1-3) as catalyst in acetonitrile. The oxidation of 2,4,6-tri-tert-butyl phenol yields the corresponding quinone after oxidative dealkylation. The oxidation of 2-amino-5-methyl phenol yields the corresponding phenoxazinone while the oxidation of 2-amino-4-tert-butyl phenol yields the phenoxazine instead of phenoxazinone. The products so obtained were analyzed by NMR and X-ray single crystallography.

  12. Synthesis, characterization, antibacterial activity, SOD mimic and interaction with DNA of drug based copper(II) complexes

    NASA Astrophysics Data System (ADS)

    Patel, Mohan N.; Dosi, Promise A.; Bhatt, Bhupesh S.; Thakkar, Vasudev R.

    2011-02-01

    Novel metal complexes of the second-generation quinolone antibacterial agent enrofloxacin with copper(II) and neutral bidentate ligands have been prepared and characterized with elemental analysis reflectance, IR and mass spectroscopy. Complexes have been screened for their in-vitro antibacterial activity against two Gram (+ve)Staphylococcus aureus, Bacillus subtilis, and three Gram (-ve)Serratia marcescens, Escherichia coli and Pseudomonas aeruginosa organisms using the double dilution technique. The binding of this complex with CT-DNA has been investigated by absorption titration, salt effect and viscosity measurements. Binding constant is ranging from 1.3 × 10 4-3.7 × 10 4. The cleavage ability of complexes has been assessed by gel electrophoresis using pUC19 DNA. The catalytic activity of the copper(II) complexes towards the superoxide anion (O 2rad -) dismutation was assayed by their ability to inhibit the reduction of nitroblue tetrazolium (NBT).

  13. Synthesis, characterization, antibacterial activity, SOD mimic and interaction with DNA of drug based copper(II) complexes.

    PubMed

    Patel, Mohan N; Dosi, Promise A; Bhatt, Bhupesh S; Thakkar, Vasudev R

    2011-02-01

    Novel metal complexes of the second-generation quinolone antibacterial agent enrofloxacin with copper(II) and neutral bidentate ligands have been prepared and characterized with elemental analysis reflectance, IR and mass spectroscopy. Complexes have been screened for their in-vitro antibacterial activity against two Gram(+ve) Staphylococcus aureus, Bacillus subtilis, and three Gram((-ve)) Serratia marcescens, Escherichia coli and Pseudomonas aeruginosa organisms using the double dilution technique. The binding of this complex with CT-DNA has been investigated by absorption titration, salt effect and viscosity measurements. Binding constant is ranging from 1.3×10(4)-3.7×10(4). The cleavage ability of complexes has been assessed by gel electrophoresis using pUC19 DNA. The catalytic activity of the copper(II) complexes towards the superoxide anion (O2.-) dismutation was assayed by their ability to inhibit the reduction of nitroblue tetrazolium (NBT). PMID:21212015

  14. Tunable DNA cleavage activity promoted by copper(ii) ternary complexes with N-donor heterocyclic ligands.

    PubMed

    Bortolotto, T; Silva-Caldeira, P P; Pich, C T; Pereira-Maia, E C; Terenzi, H

    2016-06-01

    Several small molecules have the capacity to cleave DNA promptly at high yields, even under mild conditions. Usually, this activity has no constraints, occurring without external or user control. Here, we demonstrate that UV-light exposure can greatly enhance the DNA cleavage activity promoted by four ternary copper(ii) complexes. A remarkable photocontrolled activity was achieved, which may be interesting for chemical and biochemical applications. PMID:27168172

  15. Ternary copper(II) complexes with amino acid chains and heterocyclic bases: DNA binding, cytotoxic and cell apoptosis induction properties.

    PubMed

    Ma, Tieliang; Xu, Jun; Wang, Yuan; Yu, Hao; Yang, Yong; Liu, Yang; Ding, Weiliang; Zhu, Wenjiao; Chen, Ruhua; Ge, Zhijun; Tan, Yongfei; Jia, Lei; Zhu, Taofeng

    2015-03-01

    Nowadays, chemotherapy is a common means of oncology. However, it is difficult to find excellent chemotherapy drugs. Here we reported three new ternary copper(II) complexes which have potential chemotherapy characteristics with reduced Schiff base ligand and heterocyclic bases (TBHP), [Cu(phen)(TBHP)]H2O (1), [Cu(dpz)(TBHP)]H2O (2) and [Cu(dppz)(TBHP)]H2O (3) (phen=1,10-phenanthroline, dpz=dipyrido [3,2:2',3'-f]quinoxaline, dppz=dipyrido [3,2-a:2',3'-c]phenazine, H2TBHP=2-(3,5-di-tert-butyl-2-hydroxybenzylamino)-2-benzyl-acetic acid). The DNA-binding properties of the complexes were investigated by spectrometric titrations, ethidium bromide displacement experiments and viscosity measurements. The results indicated that the three complexes, especially the complex 13, can strongly bind to calf-thymus DNA (CT-DNA). The intrinsic binding constants Kb of the ternary copper(II) complexes with CT-DNA were 1.37×10(5), 1.81×10(5) and 3.21×10(5) for 1, 2 and 3 respectively. Comparative cytotoxic activities of the copper(II) complexes were also determined by 3-(4,5-dimethylthiazol-2yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The results showed that the ternary copper(II) complexes had significant cytotoxic activity against the human lung cancer (A549), human esophageal cancer (Eca109) and human gastric cancer (SGC7901) cell lines. Cell apoptosis were detected by AnnexinV/PI flow cytometry and by Western blotting with the protein expression of p53, Bax and Bcl-2. All the three copper complexes can effectively induce apoptosis of the three human tumor cells. PMID:25555321

  16. One-pot synthesis of indenonaphthopyrans catalyzed by copper(II) triflate: a comparative study of reflux and ultrasound methods.

    PubMed

    Turhan, Kadir; Ozturkcan, S Arda; Uluer, Mehmet; Turgut, Zuhal

    2014-01-01

    An effective and environment-friendly protocol for the synthesis of indenonaphthopyrans has been developed by one-pot reaction of 2-naphthol, various aromatic aldehydes and 1,3-indandione, in the presence of copper(II) triflate as the catalyst while using reflux (Method A) and ultrasound (Method B). The Method B approach offers the advantages of a simple reaction method, short reaction time, excellent yield, and showcases the economic importance of the catalysts for such processes. PMID:25286219

  17. Flocculation of copper(II) and tetracycline from water using a novel pH- and temperature-responsive flocculants.

    PubMed

    Yang, Zhen; Jia, Shuying; Zhuo, Ning; Yang, Weiben; Wang, Yuping

    2015-12-01

    Insufficient research is available on flocculation of combined pollutants of heavy metals and antibiotics, which widely exist in livestock wastewaters. Aiming at solving difficulties in flocculation of this sort of combined pollution, a novel pH- and temperature-responsive biomass-based flocculant, carboxymethyl chitosan-graft-poly(N-isoproyl acrylamide-co-diallyl dimethyl ammonium chloride) (denoted as CND) with two responsive switches [lower critical solution temperature (LCST) and isoelectric point (IEP)], was designed and synthesized. Its flocculation performance at different temperatures and pHs was evaluated using copper(II) and tetracycline (TC) as model contaminants. CND exhibited high efficiency for coremoval of both contaminants, whereas two commercial flocculants (polyaluminum chloride and polyacrylamide) did not. Especially, flocculation performance of the dual-responsive flocculant under conditions of temperature>LCST and IEP(contaminants)copper(II) and TC were present in bridging flocculation, including charge attraction, coordination and hydrophobic effect. Based on these pairwise interactions, copper(II) and TC exerted "aid" roles to each other's removal with the existence of CND, and preferable flocculation performance was thus achieved. PMID:26162528

  18. Pyrrolidine and Piperidine Formation Via Copper(II) Carboxylate Promoted Intramolecular Carboamination of Unactivated Olefins: Diastereoselectivity and Mechanism

    PubMed Central

    Sherman, Eric S.; Fuller, Peter H.; Kasi, Dhanalakshmi; Chemler, Sherry R.

    2008-01-01

    An expanded substrate scope and in depth analysis of the reaction mechanism of the copper(II) carboxylate promoted intramolecular carboamination of unactivated alkenes is described. This method provides access to N-functionalized pyrrolidines and piperidines. Both aromatic and aliphatic γ- and δ-alkenyl N-arylsulfonamides undergo the oxidative cyclization reaction efficiently. N-Benzoyl-2-allylaniline also underwent the oxidative cyclization. The terminal olefin substrates examined were more reactive than those with internal olefins, and the latter terminated in elimination rather than carbon-carbon bond formation. The efficiency of the reaction was enhanced by the use of more organic soluble copper(II) carboxylate salts, copper(II) neodecanoate in particular. The reaction times were reduced by the use of microwave heating. High levels of diastereoselectivity were observed in the synthesis of 2,5-disubstituted pyrrolidines, wherein the cis substitution pattern predominates. The mechanism of the reaction is discussed in the context of the observed reactivity and in comparison to analogous reactions promoted by other reagents and conditions. Our evidence supports a mechanism wherein the N-C bond is formed via intramolecular syn aminocupration and the C-C bond is formed via intramolecular addition of a primary carbon radical to an aromatic ring. PMID:17428100

  19. A new tetranuclear copper(II) Schiff base complex containing Cu 4O 4 cubane core: Structural and spectral characterizations

    NASA Astrophysics Data System (ADS)

    Shit, Shyamapada; Rosair, Georgina; Mitra, Samiran

    2011-04-01

    A new tetra-nuclear coordination complex [Cu 4(HL) 4] ( 1) containing Cu 4O 4 cubane core has been synthesized by using Schiff base ligand [(OH)C 6H 4CH dbnd N sbnd C(CH 3)(CH 2OH) 2] (H 3L), obtained by the 1:1 condensation of 2-amino-2-methyl-1,3-propanediol with salicylaldehyde and thoroughly characterized by micro-analytical, FT-IR, UV-Vis, thermal and room temperature magnetic susceptibility measurements. Structural characterization of the complex has been done by single crystal X-ray diffraction analysis. Structural elucidation reveals versatile coordination modes for two identical alkoxo oxygen atoms of the Schiff base ligand; one in its deprotonated form exhibits μ 3-bridging to bind three similar copper(II) centers whilst the protonated one remains as monodentate or non-coordinating. Structural analysis also shows that the Cu 4O 4 cubane core in 1 consists of four μ 3-alkoxo oxygen bridged copper(II) atoms giving an approximately cubic array of alternating oxygen atoms and copper(II) atoms where the metal centers display both distorted square pyramidal and distorted octahedral geometries.

  20. The stability constants of copper(II) complexes with some alpha-amino acids in dioxan-water mixtures.

    PubMed

    Doğan, A; Köseoğlu, F; Kiliç, E

    2001-08-15

    In this study, the overall stability constants of copper(II) complexes with some alpha-amino acids (glycine, dl-alanine, dl-valine, l-leucine, l-asparagine, l-glutamine) were determined by potentiometric titration in water, 25% dioxan-75% water, 35% dioxan-65% water, 50% dioxan-50% water, and 60% dioxan-40% water. The titrations were performed at 25 degrees C, under nitrogen atmosphere, and the ionic strength of the medium was maintained at 0.10 M by using sodium perchlorate. The formation curves of their complexes (n-p[L]) were obtained by means of the titration data. Then the stability constants were determined in relation to these curves. The mol ratio of copper(II) to alpha-amino acid was also determined and it was found that the complexes were CuL(2) type. Another important result obtained was that the tendency of amino acids to form complexes with copper(II) was greater in dioxan-water mixtures compared to water. PMID:11488627

  1. Determination of copper(II) in the dairy product by an electrochemical sensor based on click chemistry.

    PubMed

    Qiu, Suyan; Xie, Lidan; Gao, Sen; Liu, Qida; Lin, Zhenyu; Qiu, Bin; Chen, Guonan

    2011-11-30

    Herein, a novel sensitive electrochemical sensor for copper(II) based on Cu(I) catalyzed alkyne-azide cycloaddition reaction (CuAAC) is described. The catalyst of Cu(I) species is derived from electrochemical reduction of Cu(II) through bulk electrolysis (BE) with coulometry technique. The propargyl-functionalized ferrocene (propargyl-functionalized Fc) is covalently coupled onto the electrode surface via CuAAC reaction and forms propargyl-functionalized Fc modified gold electrode, which allows a good and stable electrochemical signal. The change of current at peak (dI), detected by differential pulse voltammetry (DPV), exhibits a linear response to the logarithm of Cu(II) concentration in the range of 1.0×10(-14)-1.0×10(-9) mol L(-1). It is also found that the proposed sensor has a good selectivity for copper(II) assay even in the presence of other common metal ions. Additionally, the proposed method has been applied to determine copper(II) in the dairy product (yoghurt) with satisfactory results. PMID:22027119

  2. Synthesis and characterization of two 1D polymeric zinc(II) azido complexes derived from pyridine-N-oxide co-ligands

    NASA Astrophysics Data System (ADS)

    Mautner, Franz A.; Berger, Christian; Massoud, Salah S.

    2016-04-01

    The synthesis and structural characterization of two new polymeric zinc(II) azido complexes with pyridine-N-oxide derivative co-ligands, namely catena-[Zn(4-methylpyridine-N-oxide)(μ1,1-N3)2] (1) and catena-{[Zn2(μ2-isonicotinato-N-oxide)2(μ1,1-N3)2(H2O)3](H2O)} (2) are reported. Single crystal structure determination revealed the penta-coordinated geometry of the Zn(II) centers in the polymeric chains of 1 with di-EO azido bridging mode, whereas five and six coordination modes around Zn(II) centers are observed in complex 2, and the 1D system is formed via alternating single EO-azide and μ(O,O‧)-bridging carboxylate group of the isonicotinato-N-oxide molecules. The solid state luminescence properties of 1 were examined.

  3. Observation on symmetry properties of sodium zinc(II)-2,9,16,23-phthalocyanine tetracarboxylate in water:NaOH solution.

    PubMed

    Al-Omari, Saleh; Alghezawi, Nawash; Al-Noaimi, Mousa; Aqili, Akram; Al-Hamarneh, Ibrahim F; Marashdeh, Mohammad

    2014-05-01

    The shift of the Q-band of sodium zinc(II)-2,9,16,23-phthalocyanine tetracarboxylate (ZnPc(COONa)4) to about 800 nm is attributed to the influence of the electron-donating property of the carboxylate groups substituted in the β-position. ZnPc(COONa)4 which was found to have a symmetry of D 2h characterized by a splitting of the Q transition. This splitting was interpreted by the formation of dianionic symmetric ZnPc(COONa)4 resulting from the dissociation of the pyrrole protons as well as the possibility of Na(+) dissolution of ZnPc(COONa)4 in the aqueous solution of NaOH. PMID:24573531

  4. a Study of the Structural, Magnetic, Optical, and Electronic Properties of Several New Copper(ii) Halide and Copper(ii, i) Halide Compounds in the Solid State.

    NASA Astrophysics Data System (ADS)

    Scott, Brian Lindley

    Robin and Day classification scheme. A series of compounds of the stoichiometry (paraquat)Cu _2X_4 (X = Cl, Br, I) are investigated using x-ray crystallographic, EPR, magnetic susceptibility, differential scanning calorimetry, and electrical conductivity techniques. X-ray results show all three compounds to be pure copper(I) in character. Magnetic susceptibility results show small copper(II) contributions in the chloride and bromide analogs. In the chloride salt the copper(II) ions appear to be incorporated into the (Cu_2Cl_4) _infty chain, with accompanying vacancies to provide for charge balance. In the bromide salt a Cu_2Br_6^ {2-} dimer appears to be incorporated into the chain structure. The chloride and iodide salts show insulating behavior, but the bromide salt shows enhanced conductivity.

  5. Electrochromic and colorimetric properties of nickel(II) oxide thin films prepared by aerosol-assisted chemical vapor deposition.

    PubMed

    Sialvi, Muhammad Z; Mortimer, Roger J; Wilcox, Geoffrey D; Teridi, Asri Mat; Varley, Thomas S; Wijayantha, K G Upul; Kirk, Caroline A

    2013-06-26

    Aerosol-assisted chemical vapor deposition (AACVD) was used for the first time in the preparation of thin-film electrochromic nickel(II) oxide (NiO). The as-deposited films were cubic NiO, with an octahedral-like grain structure, and an optical band gap that decreased from 3.61 to 3.48 eV on increase in film thickness (in the range 500-1000 nm). On oxidative voltammetric cycling in aqueous KOH (0.1 mol dm(-3)) electrolyte, the morphology gradually changed to an open porous NiO structure. The electrochromic properties of the films were investigated as a function of film thickness, following 50, 100, and 500 conditioning oxidative voltammetric cycles in aqueous KOH (0.1 mol dm(-3)). Light modulation of the films increased with the number of conditioning cycles. The maximum coloration efficiency (CE) for the NiO (transmissive light green, the "bleached" state) to NiOOH (deep brown, the colored state) electrochromic process was found to be 56.3 cm(2) C(-1) (at 450 nm) for films prepared by AACVD for 15 min followed by 100 "bleached"-to-colored conditioning oxidative voltammetric cycles. Electrochromic response times were <10 s and generally longer for the coloration than the bleaching process. The films showed good stability when tested for up to 10 000 color/bleach cycles. Using the CIE (Commission Internationale de l'Eclairage) system of colorimetry the color stimuli of the electrochromic NiO films and the changes that take place on reversibly oxidatively switching to the NiOOH form were calculated from in situ visible spectra recorded under electrochemical control. Reversible changes in the hue and saturation occur on oxidation of the NiO (transmissive light green) form to the NiOOH (deep brown) form, as shown by the track of the CIE 1931 xy chromaticity coordinates. As the NiO film is oxidized, a sharp decrease in luminance was observed. CIELAB L*a*b* coordinates were also used to quantify the electrochromic color states. A combination of a low L* and positive a

  6. Equilibrium and kinetic studies for the biosorption system of copper(II) ion from aqueous solution using Tectona grandis L.f. leaves powder.

    PubMed

    Prasanna Kumar, Y; King, P; Prasad, V S R K

    2006-09-21

    The biosorption of copper(II) ions from aqueous solution by Tectona grandis L.f. was studied in a batch adsorption system as a function of pH, metal ion concentration, adsorbent concentration and adsorbent size. The biosorption capacities and rates of copper(II) ions onto T. grandis L.f. were evaluated. The Langmuir, Freundlich, Redlich-Peterson and Temkin adsorption models were applied to describe the isotherms and isotherm constants. Biosorption isothermal data could be well interpreted by the Langmuir model with maximum adsorption capacity of 15.43 mg/g of copper(II) ion on T. grandis L.f. leaves powder. The kinetic experimental data properly correlated with the second-order kinetic model. Various thermodynamic parameters such as deltaG(o), deltaH(o), and deltaS(o) were calculated indicating that this system was a spontaneous and exothermic process. PMID:16704905

  7. The effect of copper(II), iron(II) sulphate, and vitamin C combinations on the weak antimicrobial activity of (+)-catechin against Staphylococcus aureus and other microbes.

    PubMed

    Holloway, Andrew C; Mueller-Harvey, Irene; Gould, Simon W J; Fielder, Mark D; Naughton, Declan P; Kelly, Alison F

    2012-12-01

    Few attempts have been made to improve the activity of plant compounds with low antimicrobial efficacy. (+)-Catechin, a weak antimicrobial tea flavanol, was combined with putative adjuncts and tested against different species of bacteria. Copper(II) sulphate enhanced (+)-catechin activity against Pseudomonas aeruginosa but not Staphylococcus aureus, Proteus mirabilis or Escherichia coli. Attempts to raise the activity of (+)-catechin against two unresponsive species, S. aureus and E. coli, with iron(II) sulphate, iron(III) chloride, and vitamin C, showed that iron(II) enhanced (+)-catechin against S. aureus, but not E. coli; neither iron(III) nor combined iron(II) and copper(II), enhanced (+)-catechin activity against either species. Vitamin C enhanced copper(II) containing combinations against both species in the absence of iron(II). Catalase or EDTA added to active samples removed viability effects suggesting that active mixtures had produced H(2)O(2)via the action of added metal(II) ions. H(2)O(2) generation by (+)-catechin plus copper(II) mixtures and copper(II) alone could account for the principal effect of bacterial growth inhibition following 30 minute exposures as well as the antimicrobial effect of (+)-catechin-iron(II) against S. aureus. These novel findings about a weak antimicrobial flavanol contrast with previous knowledge of more active flavanols with transition metal combinations. Weak antimicrobial compounds like (+)-catechin within enhancement mixtures may therefore be used as efficacious agents. (+)-Catechin may provide a means of lowering copper(II) or iron(II) contents in certain crop protection and other products. PMID:23138340

  8. New manganese(II) and nickel(II) coordination compounds with N,O-polydentate ligands obtained from pyridoxal and tripodal units

    NASA Astrophysics Data System (ADS)

    Ebani, Patrícia Regina; Fontana, Liniquer Andre; Campos, Patrick Teixeira; Rosso, Eduardo F.; Piquini, Paulo C.; Iglesias, Bernardo Almeida; Back, Davi Fernando

    2016-09-01

    We have reported the synthesis involving the condensation of pyridoxal with tris(2-aminoethyl)amine obtained a tripodal ligand, as well as its subsequent complexation with the manganese(II) and nickel(II) ions. The structural analysis revealed, in the case of complex 1, the formation of a monomeric complex with Mn(II) species. In the complex 2, with Ni(II) metal ion, we describe the probable mechanism for the formation of hemiacetal in these complexes. Only the complex 1 catalyze the dismutation of superoxide efficiently with IC50 equal to 3.38 μM, evaluated through the nitro blue tetrazolium photoreduction inhibition superoxide dismutase assay, in aqueous solution of pH 7.8. Density functional theory calculations are done to characterize and compare the molecular frontier orbitals of the Mn(II) and Ni(II) complexes.

  9. Synthesis, crystal structure and characterization of a new mixed ligand cationic-anionic nickel(II) complex containing 1,4-diazepane

    NASA Astrophysics Data System (ADS)

    Sain, Saugata; Saha, Rajat; Pilet, Guillaume; Bandyopadhyay, Debasis

    2010-12-01

    A new mixed ligand cationic-anionic nickel(II) complex, [NiL 2][Ni(NCS) 4(H 2O) 2] ( 1), where L = 1,4-diazepane has been synthesized by reacting nickel perchlorate with 1,4-diazepane and ammonium thiocyanate in the 1:1:2 M ratio. The complex has been characterized by elemental analysis, IR spectroscopy, TGA and single crystal X-ray diffraction studies. Structural studies reveal the presence of two independent mononuclear complex ions in 1 viz., a square planar [NiL 2] 2+ and an octahedral [Ni(NCS) 4(H 2O) 2] 2- which are held together by H-bonding to form a 3D supramolecular structure in the solid state.

  10. Synthesis, antioxidant activities of the nickel(II), iron(III) and oxovanadium(IV) complexes with N2O2 chelating thiosemicarbazones

    NASA Astrophysics Data System (ADS)

    Bal-Demirci, Tülay; Şahin, Musa; Özyürek, Mustafa; Kondakçı, Esin; Ülküseven, Bahri

    The nickel(II), iron(III) and oxovanadium(IV) complexes of the N2O2 chelating thiosemicarbazones were synthesized using 4-hydroxysalicyladehyde-S-methylthiosemicarbazone and R1-substitute-salicylaldehyde (R1: 4-OH, H) in the presence of Ni(II), Fe(III), VO(IV) ions by the template reaction. The structures of the thiosemicarbazone complexes were characterized by FT-IR, 1H NMR, elemental, ESI-MS and APCI-MS analysis. The synthesized compounds were screened for their antioxidant capacity by using the cupric reducing antioxidant capacity (CUPRAC) method. Trolox equivalent antioxidant capacity (TEAC) of iron(III) complex, 1c, was measured to be higher than that of the other complexes. Other parameters of antioxidant activity (scavenging effects on rad OH, O2rad - and H2O2) of these compounds were also determined. All the compounds have shown encouraging ROS scavenging activities.

  11. Synthesis, antioxidant activities of the nickel(II), iron(III) and oxovanadium(IV) complexes with N2O2 chelating thiosemicarbazones.

    PubMed

    Bal-Demirci, Tülay; Sahin, Musa; Ozyürek, Mustafa; Kondakçı, Esin; Ulküseven, Bahri

    2014-05-21

    The nickel(II), iron(III) and oxovanadium(IV) complexes of the N2O2 chelating thiosemicarbazones were synthesized using 4-hydroxysalicyladehyde-S-methylthiosemicarbazone and R1-substitute-salicylaldehyde (R1: 4-OH, H) in the presence of Ni(II), Fe(III), VO(IV) ions by the template reaction. The structures of the thiosemicarbazone complexes were characterized by FT-IR, (1)H NMR, elemental, ESI-MS and APCI-MS analysis. The synthesized compounds were screened for their antioxidant capacity by using the cupric reducing antioxidant capacity (CUPRAC) method. Trolox equivalent antioxidant capacity (TEAC) of iron(III) complex, 1c, was measured to be higher than that of the other complexes. Other parameters of antioxidant activity (scavenging effects on •OH, O2(•-) and H2O2) of these compounds were also determined. All the compounds have shown encouraging ROS scavenging activities. PMID:24656797

  12. Structural study of two N(4)-substituted thiosemicarbazones prepared from 1-phenyl-1,2-propanedione-2-oxime and their binuclear nickel(II) complexes

    NASA Astrophysics Data System (ADS)

    Kaminsky, Werner; Jasinski, Jerry P.; Woudenberg, Richard; Goldberg, Karen I.; West, Douglas X.

    2002-05-01

    The crystal structures of the oxime/thiosemicarbazones 1-phenyl-1-{ N(4)-methyl- and 1-phenyl-1-{ N(4)-ethylthiosemicarbazone}-2-oximepropane, H 2Po4M and H 2Po4E, were found to have the oxime and thiosemicarbazone moieties on opposite sides of the carbon-carbon backbone. Intermolecular hydrogen bonding involves the oxime function forming a symmetrical dimer for both compounds. The structures of the binuclear nickel(II) complexes, [Ni(Po4M)] 2 and [Ni(Po4E)] 2, show that bridging by the oximato N-O results in a centrosymmetric arrangement of the two planar nickel centers in each complex. The coordinated thiosemicarbazonato moieties undergo the expected changes in bond distances and angles compared to H 2Po4M and H 2Po4E.

  13. Synthesis, Biological, Spectral, and Thermal Investigations of Cobalt(II) and Nickel(II) Complexes of N-Isonicotinamido -2′,4′-Dichlorobenzalaldimine

    PubMed Central

    Agarwal, Ram K.; Sharma, Deepak; Singh, Lakshman; Agarwal, Himanshu

    2006-01-01

    A new series of 12 complexes of cobalt(II) and nickel(II) with N-isonicotinamido-2′,4′-dichlorobenzalaldimine (INH-DCB) with the general composition MX2 · n(INH-DCB) [M = Co(II) or Ni(II), X = Cl− ,Br−, NO3−, NCS−, or CH3COO−, n = 2; X = ClO4−, n = 3] have been synthesized. The nature of bonding and the stereochemistry of the complexes have been deduced from elemental analyses, infrared, electronic spectra, magnetic susceptibility, and conductivity measurements. An octahedral geometry has been suggested for all the complexes. The metal complexes were screened for their antifungal and antibacterial activities on different species of pathogenic fungi and bacteria and their biopotency has been discussed. PMID:17497006

  14. Nickel(I) and nickel(III) complexes of substituted tetraaza macrocycles formed by pulse radiolysis and electrochemistry of nickel(II) precursors

    SciTech Connect

    Bernhardt, P.V.; Lawrance, G.A.; Sangster, D.F.

    1988-11-02

    The square-planar nickel(II) complexes of the ligands 8-methyl-8-nitro-1,3,6,10,13,15-hexaazatricyclo(13.1.1.1/sup 13,15/)octadecane, 8-amino-8-methyl-1,3,6,10,13,15-hexaazatricyclo(13.1.1.1/sup 13,15/)octadecane, 3,7-bis(2-aminoethyl)-1,3,5,7-tetraazabicyclo(3.3.1)nonane, and 9-methyl-9-nitro-1,4,7,11-tetraazacyclotridecane (I-IV) react rapidly with hydroxyl radicals and aquated electrons (e/sub aq/). The initial transient products of these reactions decay via first-order kinetics within a few milliseconds in neutral aqueous solution at 22/degrees/C in all cases. Electronic spectra and decay rate constants, as well as formation rate constants, are reported for all transients. Reaction of the nitro-substituted complexes with e/sub aq/ led to electron addition to the nitro group rather than to the metal center; otherwise, a Ni/sup I/ transient is observed. Following reaction with OH, the product of the initial decay remains a Ni/sup III/ species. This is more long-lived, and stabilization of Ni/sup III/ by axial coordination of the pendant amine in II is indicated. No notable stabilization of Ni/sup I/ or Ni/sup III/ from the presence of the bicyclic azamethylene football in I-III occurs. Cyclic voltammetry in acetonitrile identified both one-electron oxidation and one-electron reduction processes for the nickel(II) complexes, as well as nitro group reduction, where this group was pendant to the macrocycle. 34 references, 3 figures, 3 tables.

  15. Copper(II) complexes of substituted salicylaldehyde dibenzyl semicarbazones: synthesis, cytotoxicity and interaction with quadruplex DNA.

    PubMed

    Munira Haidad Ali, Siti; Yan, Yaw-Kai; Lee, Peter P F; Khong, Kenny Zhi Xiang; Alam Sk, Mahasin; Lim, Kok Hwa; Klejevskaja, Beata; Vilar, Ramon

    2014-01-21

    A series of substituted salicylaldehyde dibenzyl semicarbazones [RC6H3(OH)CH=N-NHCON(CH2Ph)2] and their copper(II) complexes were synthesized and characterized. The chloridocopper(II) complexes of the 4-OH and 5-OH substituted ligands (complexes 9 and 7) show modest affinity and good selectivity (over duplex DNA) for the quadruplex formed from the human telomeric (HTelo) DNA sequence. Substitution of the chlorido ligands of these two complexes with pyridine yielded derivatives (7-py and 9-py) with increased affinity for HTelo. These derivatives also show good selectivity for HTelo over calf-thymus DNA (170- and 211-fold, respectively). The X-ray crystal structures of 9 and 9-py were determined. Molecular docking studies based on these structures show that the complexes stack on the 5'-end of the HTelo quadruplex, with the hydroxyl group forming a hydrogen bond with a guanine residue. Complexes 7, 9, 7-py and 9-py display significant cytotoxicity against MOLT-4 human leukaemia cells. Interestingly, they have low to negligible cytotoxicity against the non-cancerous IMR-90 human fibroblasts. PMID:24202733

  16. Synthesis, crystal structure, DNA interaction and anticancer activity of tridentate copper(II) complexes.

    PubMed

    Li, Guan-Ying; Du, Ke-Jie; Wang, Jin-Quan; Liang, Jie-Wen; Kou, Jun-Feng; Hou, Xiao-Juan; Ji, Liang-Nian; Chao, Hui

    2013-02-01

    Three new tridentate copper(II) complexes [Cu(dthp)Cl(2)] (1) (dthp=2,6-di(thiazol-2-yl)pyridine), [Cu(dmtp)Cl(2)] (2) (dmtp=2,6-di(5-methyl-4H-1,2,4-triazol-3-yl)pyridine) and [Cu(dtp)Cl(2)] (3) (dtp=2,6-di(4H-1,2,4-triazol-3-yl)pyridine) have been synthesized and characterized. Crystal structure of complex 1 shows that the complex existed as distorted square pyramid with five co-ordination sites occupied by the tridentate ligand and the two chlorine anions. Ethidium bromide displacement assay, viscosity measurements, circular dichroism studies and cyclic voltammetric experiments suggested that these complexes bound to DNA via an intercalative mode. Three Cu(II) complexes were found to efficiently cleave DNA in the presence of sodium ascorbate, and singlet oxygen ((1)O(2)) and hydrogen peroxide were proved to contribute to the DNA cleavage process. They exhibited anticancer activity against HeLa, Hep-G2 and BEL-7402 cell lines. Nuclear chromatin cleavage has also been observed with AO/EB staining assay and the alkaline single-cell gel electrophoresis (comet assay). The results demonstrated that three Cu(II) complexes cause DNA damage that can induce the apoptosis of BEL-7402 cells. PMID:23186647

  17. A lariat-functionalized copper(II) diimine-dioxime complex.

    PubMed

    Kiani, Salma; Staples, Richard J; Packard, Alan B

    2002-12-01

    The dimeric title copper(II) complex, diaqua-1kappaO,2kappaO-bis[3,9-dimethyl-6-(2-pyridylmethyl)-4,8-diazaundeca-3,8-diene-2,10-dione dioximato(1-)]-1k(4)N(2),N(4),N(8),N(10);1:2kappa(5)O(2):N(2),N(4),N(8),N(10)-dicopper(II) diperchlorate, [Cu(2)(C(17)H(24)N(5)O(2))(2)](ClO(4))(2), crystallizes with one Cu atom in a square-pyramidal environment and the other Cu atom displaying a distorted octahedral coordination. In each case, the four N atoms in the core of the ligand (two imine and two oxime N atoms) form the base of the pyramid, with a water molecule at an apex. The two parts of the dimer are linked by an interaction [2.869 (2) A] between one of the Cu atoms and one of the oxime O atoms coordinated to the second Cu atom, and also by a hydrogen bond between the apical water molecule on the second Cu atom and the pyridyl N atom from the coordination sphere of the first Cu atom. The pyridyl N atoms of the lariat arms are not coordinated to either of the Cu atoms. Thus, this potentially pentadentate ligand is only tetradentate when coordinated to Cu(II). PMID:12466608

  18. Chiral copper(II) complex based on natural product rosin derivative as promising antitumour agent.

    PubMed

    Fei, Bao-Li; Huang, Zhi-Xiang; Xu, Wu-Shuang; Li, Dong-Dong; Lu, Yang; Gao, Wei-Lin; Zhao, Yue; Zhang, Yu; Liu, Qing-Bo

    2016-07-01

    To evaluate the biological preference of chiral drug candidates for molecular target DNA, the synthesis and characterization of a chiral copper(II) complex (2) of a chiral ligand N,N'-(pyridin-2-ylmethylene) dehydroabietylamine (1) was carried out. The interactions of 1 and 2 with salmon sperm DNA were investigated by viscosity measurements, UV, fluorescence and circular dichroism (CD) spectroscopic techniques. Absorption spectral, emission spectral and viscosity analysis reveal that 1 and 2 interacted with DNA through intercalation and 2 exhibited a higher DNA binding ability. In the absence/presence of ascorbic acid, 1 and 2 cleaved supercoiled pBR322 DNA by single-strand and 2 displayed stronger DNA cleavage ability. In addition, in vitro cytotoxicity of 1 and 2 against HeLa, SiHa, HepG-2 and A431 cancer cell lines study show that they exhibited effective cytotoxicity against the tested cell lines, notably, 2 showed a superior cytotoxicity than the widely used drug cisplatin under identical conditions, indicating it has the potential to act as effective anticancer drug. Flow cytometry analysis indicates 2 produced death of HeLa cancer cells through an apoptotic pathway. Cell cycle analysis demonstrates that 2 mainly arrested HeLa cells at the S phase. The study represents the first step towards understanding the mode of the promising chiral rosin-derivative based copper complexes as chemotherapeutics. PMID:27088508

  19. Glycosidase- and β-lactamase-like activity of dinuclear copper(II) patellamide complexes.

    PubMed

    Comba, Peter; Eisenschmidt, Annika; Kipper, Nora; Schießl, Jasmin

    2016-06-01

    Prochloron, a blue-green algae belonging to ancient prokaryotes, produces, like other cyanobacteria, cyclic pseudo-peptides, which are also found in its obligate symbiont ascidiae (Lissoclinum patellum). Although research has focused for some time on the putative metabolic function of these cyclic peptides, to date it is still not understood. Their role might be connected to the increased concentrations of divalent metal ions, especially Cu(II), found in ascidiae. Dinuclear copper(II) complexes of cyclic pseudo-peptides revealed a broad hydrolytic capacity, including carboanhydrase and phosphatase activity. This study reports their β-lactamase as well as α- and β-glycosidase activity with kcat=(11.34±0.91)ˑ10(-4)s(-1) for β-lactamase, kcat=(1.55±0.13)ˑ10(-4)s(-1) for α-glycosidase and kcat=(1.22±0.09)ˑ10(-4)s(-1) for β-glycosidase activity. PMID:26921720

  20. The structures and thermodynamic stability of copper(II) chloride surfaces.

    PubMed

    Altarawneh, Mohammednoor; Jiang, Zhong-Tao; Dlugogorski, Bogdan Z

    2014-11-28

    Using density functional theory calculations of periodic slabs, within the generalised gradient approximation, this study provides optimised structures for all plausible terminations of copper(II) chloride surfaces along the three low-index orientations. The ab initio atomistic thermodynamic approach serves to construct a thermodynamic stability diagram for CuCl2 configurations as a function of the chemical potential of chlorine (ΔμCl(T,P)). We observe a shift in thermodynamic stability ordering at around ΔμCl(T,P) = -1.0 eV between a copper-chlorine terminated (001) surface (i.e., (001)CuCl) and a (001) chlorine-covered surface (i.e., (001)Cl). This conclusion accords with experimental observations that report CuCl-bulk like structures, acting as a prerequisite for the formation of CuCl2-bulk like arrangements in the course of copper chlorination. Profound stabilities and optimised structures of (001)CuCl and (001)Cl configurations are discussed within the context of the functionality of CuCl2 as the chief chlorination and condensation catalyst of aromatic pollutants under conditions relevant to their formation in thermal systems, i.e. 400-1000 K, a total operating pressure of 1.0 atm and PCl2 = 10(-6)-10(-4) atm (1.0-100.0 ppm). PMID:25294121

  1. A lariat-functionalized copper(II) diimine—dioxime complex

    PubMed Central

    Kiani, Salma; Staples, Richard J.; Packard, Alan B.

    2013-01-01

    The dimeric title copper(II) complex, diaqua-1κO,2κO-bis[3,9-dimethyl-6-(2-pyridylmethyl)-4,8-diazaundeca-3,8-diene-2,10-dione dioximato(1–)]-1k4N2,N4,N8,N10;1:2κ5O2:N2,-N4,N8,N10-dicopper(II) diperchlorate, [Cu2(C17H24N5O2)2]-(ClO4)2, crystallizes with one Cu atom in a square-pyramidal environment and the other Cu atom displaying a distorted octahedral coordination. In each case, the four N atoms in the core of the ligand (two imine and two oxime N atoms) form the base of the pyramid, with a water molecule at an apex. The two parts of the dimer are linked by an interaction [2.869 (2) Å] between one of the Cu atoms and one of the oxime O atoms coordinated to the second Cu atom, and also by a hydrogen bond between the apical water molecule on the second Cu atom and the pyridyl N atom from the coordination sphere of the first Cu atom. The pyridyl N atoms of the lariat arms are not coordinated to either of the Cu atoms. Thus, this potentially pentadentate ligand is only tetradentate when coordinated to CuII. PMID:12466608

  2. Spectroscopic study of copper(II) complexes with carboxymethyl dextran and dextran sulfate

    NASA Astrophysics Data System (ADS)

    Glišić, S.; Nikolić, G.; Cakić, M.; Trutić, N.

    2015-07-01

    The copper(II) ion complexes with carboxymethyl dextran (CMD) and dextran sulfate (DS) were studied by different methods. Content of copper was determined by atomic absorption spectroscopy. It was found that copper : ligand mole ratio (Cu : CMD) is 1 : 2, and Cu : DS is 1 : 1 by mole ratio method. Spectrophotometric parameters of synthesized compounds are characteristic for Cu(II) ion in octahedral ( O h ) coordination. Analyzing of FTIR spectra in ν(C=O) vibration region has showed that -COOH group acts as bidentate ligand, while the compounds of Cu(II) with DS copper ions are in the region of four oxygen atoms of two adjacent sulfo groups. The presence of crystalline water was determined by isotopic substitution of H2O molecules with D2O molecules. Comparison of spectra recorded at room (RT) and liquid nitrogen temperature (LNT) has enabled detection bands of water molecules libration indicating that they are coordinated complementing coordination sphere of Cu(II) ions to six. The complexes are of Cu(II) · (CMD)2 · (H2O)2 or Cu(II) · DS · (H2O)2 type. The similarities of the γ(C-H) range in a part of FTIR spectra indicate that there is no difference in the conformation of the 4 C 1 glucopyranose (Glc) unit CMD and DS synthesized Cu(II) complexes.

  3. Synthesis, structural characterization, cytotoxic properties and DNA binding of a dinuclear copper(II) complex.

    PubMed

    Ferreira, B J M Leite; Brandão, P; Meireles, M; Martel, Fátima; Correia-Branco, Ana; Fernandes, Diana M; Santos, T M; Félix, V

    2016-08-01

    In this study a novel dinuclear copper(II) complex with adenine and phenanthroline has been synthesized and its structure determined by single crystal X-ray diffraction. In the dinuclear complex [Cu₂(μ-adenine)₂(phen)₂(H2O)2](NO3)4·0.5H2O (phen=1,10-phenanthroline) (1) the two Cu(II) centres exhibit a distorted square pyramidal coordination geometry linked by two nitrogen donors from adenine bridges leading to a Cu-Cu distance of 3.242(3)Å. Intramolecular and intermolecular π⋯π interactions as well as an H-bonding network were observed. The antitumor capacity of the complex has been tested in vitro against human cancer cell lines, cervical carcinoma (HeLa) and colorectal adenocarcinoma (Caco-2), by metabolic tests, using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide as reagent. The complex 1 has remarkable low IC50 values of 0.87±0.06μM (HeLa) and 0.44±0.06μM (Caco-2), when compared with values for cisplatin against the same cell lines. The interaction of complex 1 with calf thymus DNA (CT DNA) was further investigated by absorption and fluorescence spectroscopic methods. A binding constant of 5.09×10(5)M(-1) was obtained from UV-vis absorption studies. PMID:27157979

  4. Immobilized copper(II) macrocyclic complex on MWCNTs with antibacterial activity

    NASA Astrophysics Data System (ADS)

    Tarlani, Aliakbar; Narimani, Khashayar; Mohammadipanah, Fatemeh; Hamedi, Javad; Tahermansouri, Hasan; Amini, Mostafa M.

    2015-06-01

    In a new approach, a copper(II) tetraaza macrocyclic complex (CuTAM) was covalently bonded on modified multi-walled carbon nanotubes (MWCNTs). To achieve this purpose, MWCNTs were converted to MWCNT-COCl and then reacted to NH groups of TAM ligand. The prepared material was characterized by Fourier Transform Infrared (FT-IR), X-ray diffraction (XRD), Raman spectroscopy, thermal gravimetric analysis (TGA), and FESEM (field emission scanning electron microscopy). FT-IR and TGA demonstrated the presence of the organic moieties, and XRD proved that the structure of MWCNTs remained intact during the three modification steps. An increase in the ID/IG ratio in Raman spectra confirmed the surface modifications. Finally, the samples were subjected to an antibacterial assessment to compare their biological activity. The antibacterial test showed that the grafted complex on the surface of the nanotube (MWCNT-CO-CuTAM) has higher antibacterial activity against Bacillus subtilis ATCC 6633 than the MWCNT-COOH and CuTAM with 1000 and 2000 μg/mL.

  5. Human telomeric G-quadruplex DNA interactions of N-phenanthroline glycosylamine copper(II) complexes.

    PubMed

    Duskova, Katerina; Sierra, Sara; Arias-Pérez, María-Selma; Gude, Lourdes

    2016-01-01

    We report in this article the interactions of five N-(1,10-phenanthrolin-5-yl)-β-glycopyranosylamine copper(II) complexes with G-quadruplex DNA. Specifically, the interactions of these compounds with a human telomeric oligonucleotide have been assessed by fluorescence-based assays (FRET melting and G4-FID), circular dichroism and competitive equilibrium dialysis experiments. The metal complexes bind and stabilize G-quadruplex DNA structures with apparent association constants in the order of 10(4)-10(5)M(-1) and the affinity observed is dependent on the ionic conditions utilized and the specific nature of the carbohydrate moiety tethered to the 1,10-phenanthroline system. The compounds showed only a slight preference to bind G-quadruplex DNA over duplex DNA when the quadruplex DNA was folded in sodium ionic conditions. However, the binding affinity and selectivity, although modest, were notably increased when the G-quadruplex DNA was folded in the presence of potassium metal ions. Moreover, the study points towards a significant contribution of groove and/or loop binding in the recognition mode of quadruplex structures by these non-classical quadruplex ligands. The results reported herein highlight the potential and the versatility of carbohydrate bis-phenanthroline metal-complex conjugates to recognize G-quadruplex DNA structures. PMID:26678174

  6. Strong effect of copper(II) coordination on antiproliferative activity of thiosemicarbazone-piperazine and thiosemicarbazone-morpholine hybrids.

    PubMed

    Bacher, Felix; Dömötör, Orsolya; Chugunova, Anastasia; Nagy, Nóra V; Filipović, Lana; Radulović, Siniša; Enyedy, Éva A; Arion, Vladimir B

    2015-05-21

    In this study, 2-formylpyridine thiosemicarbazones and three different heterocyclic pharmacophores were combined to prepare thiosemicarbazone–piperazine mPip-FTSC (HL1) and mPip-dm-FTSC (HL2), thiosemicarbazone–morpholine Morph-FTSC (HL3) and Morph-dm-FTSC (HL4), thiosemicarbazone–methylpyrrole-2-carboxylate hybrids mPyrr-FTSC (HL5) and mPyrr-dm-FTSC (HL6) as well as their copper(II) complexes [CuCl(mPipH-FTSC-H)]Cl (1 + H)Cl, [CuCl(mPipH-dm-FTSC-H)]Cl (2 + H)Cl, [CuCl(Morph-FTSC-H)] (3), [CuCl(Morph-dm-FTSC-H)] (4), [CuCl(mPyrr-FTSC-H)(H2O)] (5) and [CuCl(mPyrr-dm-FTSC-H)(H2O)] (6). The substances were characterized by elemental analysis, one- and two-dimensional NMR spectroscopy (HL1–HL6), ESI mass spectrometry, IR and UV–vis spectroscopy and single crystal X-ray diffraction (1–5). All compounds were prepared in an effort to generate potential antitumor agents with an improved therapeutic index. In addition, the effect of structural alterations with organic hybrids on aqueous solubility and copper(II) coordination ability was investigated. Complexation of ligands HL2 and HL4 with copper(II) was studied in aqueous solution by pH-potentiometry, UV–vis spectrophotometry and EPR spectroscopy. Proton dissociation processes of HL2 and HL4 were also characterized in detail and microscopic constants for the Z/E isomers were determined. While the hybrids HL5, HL6 and their copper(II) complexes 5 and 6 proved to be insoluble in aqueous solution, precluding antiproliferative activity studies, the thiosemicarbazone–piperazine and thiosemicarbazone–morpholine hybrids HL1–HL4, as well as copper(II) complexes 1–4 were soluble in water enabling cytotoxicity assays. Interestingly, the metal-free hybrids showed very low or even a lack of cytotoxicity (IC50 values > 300 μM) in two human cancer cell lines HeLa (cervical carcinoma) and A549 (alveolar basal adenocarcinoma), whereas their copper(II) complexes were cytotoxic showing IC50 values from 25.5 to 65.1

  7. Copper(II) imidazolate frameworks as highly efficient photocatalysts for reduction of CO2 into methanol under visible light irradiation

    NASA Astrophysics Data System (ADS)

    Li, Jingtian; Luo, Deliang; Yang, Chengju; He, Shiman; Chen, Shangchao; Lin, Jiawei; Zhu, Li; Li, Xin

    2013-07-01

    Three copper(II) imidazolate frameworks were synthesized by a hydrothermal (or precipitation) reaction. The catalysts were characterized by X-ray diffraction (XRD), nitrogen adsorption, transmission electron microscopy (TEM), ultraviolet-visible spectroscopy (UV-vis), Fourier transform infrared spectra (FTIR), thermogravimetry (TG). Meanwhile, the photocatalytic activities of the samples for reduction of CO2 into methanol and degradation of methylene blue (MB) under visible light irradiation were also investigated. The results show that the as-prepared samples exhibit better photocatalytic activities for the reduction of carbon dioxide into methanol with water and degradation of MB under visible light irradiation. The orthorhombic copper(II) imidazolate frameworks with a band gap of 2.49 eV and green (G) color has the best photocatalytic activity for reduction of CO2 into methanol, 1712.7 μmol/g over 5 h, which is about three times as large as that of monoclinic copper(II) imidazolate frameworks with a band gap 2.70 eV and blue (J) color. The degradation kinetics of MB over three photocatalysts fitted well to the apparent first-order rate equation and the apparent rate constants for the degradation of MB over G, J and P (with pink color) are 0.0038, 0.0013 and 0.0016 min-1, respectively. The synergistic effects of smallest band gap and orthorhombic crystal phase structure are the critical factors for the better photocatalytic activities of G. Moreover, three frameworks can also be stable up to 250 °C. The investigation of Cu-based zeolitic imidazolate frameworks maybe provide a design strategy for a new class of photocatalysts applied in degradation of contaminations, reduction of CO2, and even water splitting into hydrogen and oxygen under visible light.

  8. Syntheses, characterization, and SOD activity studies of barbital-based nickel(II) complexes with different chelating amines: The X-ray crystal structures of Barb-H and [Ni(Barb)2(en)2] (Barb = 5,5-diethylbarbiturate)

    NASA Astrophysics Data System (ADS)

    Ibrahim, Mohamed M.; Mersal, Gaber A. M.; Al-Juaid, Salih; El-Shazly, Samir A.

    2014-01-01

    Four new mixed ligand nickel(II) complexes, viz., [Ni(Barb)2(H2O)4] 1, [Ni(Barb)2(en)2] 2, [Ni(Barb)2(pn)2] 3, and [Ni(Barb)2(BPA)(H2O)] 4 (Barb = 5,5-diethylbarbiturate, en = ethylenediamine, pn = propylenediamine, and BPA = bis(2-picolyl)amine) have been synthesized and characterized by means of elemental analysis, spectroscopic (FT-IR, Raman, and UV-Vis), and thermal analysis measurements. The spectral techniques suggest that all the nickel(II) complexes (1-4) exhibit octahedral geometry. The very low electrical conductance of the complexes supports their neutral nature. The monomeric nature of the complexes was assessed from their electronic spectra. X-ray diffraction studies were performed for the drug Barb-H and its nickel(II) complex 2. Complex 2 crystallizes in monoclinic space group P21/c with Z = 2. The barbital drug is N-coordinated and the en molecules act as bichelating ligands, leading to an NiN6 octahedral coordination. Molecules of complex 2 are connected via NH⋯O hydrogen bonds, involving hydrogen atoms of both Barb and en ligands. The redox behavior of all complexes was investigated by cyclic voltammetry. Superoxide dismutase activity of these complexes has also been measured.

  9. Structural characterization of a metal-based perfusion tracer: copper(II) pyruvaldehyde bis(N4-methylthiosemicarbazone).

    PubMed

    John, E; Fanwick, P E; McKenzie, A T; Stowell, J G; Green, M A

    1989-01-01

    Copper(II) pyruvaldehyde bis(N4-methylthiosemicarbazone), Cu(PTSM), has been obtained as a dark red crystalline solid from EtOH-DMSO solvent mixture and structurally characterized by x-ray crystallography. The molecule possesses the expected pseudo-square planar N2S2 metal coordination sphere; however, the copper center also interacts through its axial coordination site with the sulfur atom of an adjacent Cu(PTSM) molecule in the crystal lattice. The structure of this compound is compared with the structures of other metal complexes that have been proposed in the nuclear medicine literature as perfusion tracers. PMID:2621114

  10. Spectrophotometric determination of copper(II) in pharmaceutical, biological and water samples by 4-(2'-benzothiazolylazo)-salicylic acid

    NASA Astrophysics Data System (ADS)

    Hashem, E. Y.; Seleim, M. M.; El-Zohry, A. M.

    2011-09-01

    A highly sensitive method is proposed to determine copper(II) ions by forming a stable complex through their interaction with 4-(2'-benzothiazolylazo)-salicylic acid (BTAS) at room temperature and pH of about 5.0. The complex gave a maximum absorption at λ = 485 nm with a molar absorptivity coefficient of 2.35·104 l/(mol·cm). The linear range for the copper determination is 0.63-5.04 mg/l. The method can be applied to determine copper ions in different biological specimens like some drugs and water samples.

  11. Synthesis, characterization, and evaluation of five coordinated copper(II) complexes as antibacterial, artificial nuclease, and SOD mimics.

    PubMed

    Patel, M N; Gandhi, D S; Parmar, P A

    2012-01-01

    The copper(II) complexes with ciprofloxacin (CFLH), levofloxacin (LFLH), norfloxacin (NFLH), and neutral bidentate ligands have been synthesized and characterized. The complexes have been evaluated for their antibacterial activity against selective species. Complexes have been also checked for their interacting behavior with DNA, and were found to have two different modes of interaction, classical and partial intercalation. Tested complexes were found to be better antioxidants with their IC(50) values ranging from 0.51 to 0.97 μM. PMID:22646085

  12. Synthesis, characterization, biological activity, molecular modeling and docking studies of complexes 4-(4-hydroxy)-3-(2-pyrazine-2-carbonyl)hydrazonomethylphenyl-diazen-yl-benzenesulfonamide with manganese(II), cobalt(II), nickel(II), zinc(II) and cadmium(II)

    NASA Astrophysics Data System (ADS)

    Alaghaz, Abdel-Nasser M. A.; Zayed, Mohamed E.; Alharbi, Suliman A.; Ammar, Reda A. A.; Elhenawy, Ahmed

    2015-03-01

    A new series of complexes of 4-(4-hydroxy)-3-(2-pyrazine-2-carbonyl)hydrazonomethylphenyl-diazen-yl-benzenesulfonamide (HL) with Mn(II), Co(II), Ni(II), Zn(II) and Cd(II) have been prepared and characterized by different physical techniques. The IR spectra of the prepared complexes were suggested that the ligand behaves as a tri-dentate ligand through the carbonyl oxygen, azomethine nitrogen and phenolic oxygen atoms (ONO). Electronic spectra and magnetic susceptibility measurements reveal octahedral geometry for all complexes. The elemental analyses and mass spectral data have justified the ML2 composition of complexes. The EPR spectra of Mn(II), Co(II) and Ni(II) complexes support the mononuclear structure. The crystal field splitting, Racah repulsion and nephelauxetic parameters and determined from the electronic spectra of the complexes. Thermal properties and decomposition kinetics of all complexes are investigated. The geometry of the metal complexes has been optimized with the help of molecular modeling. The biological activity of these compounds against various fungi has been investigated.

  13. Synthesis and spectral characterization of mono- and binuclear copper(II) complexes derived from 2-benzoylpyridine-N⁴-methyl-3-thiosemicarbazone: crystal structure of a novel sulfur bridged copper(II) box-dimer.

    PubMed

    Jayakumar, K; Sithambaresan, M; Aiswarya, N; Kurup, M R Prathapachandra

    2015-03-15

    Mononuclear and binuclear copper(II) complexes of 2-benzoylpyridine-N(4)-methyl thiosemicarbazone (HL) were prepared and characterized by a variety of spectroscopic techniques. Structural evidence for the novel sulfur bridged copper(II) iodo binuclear complex is obtained by single crystal X-ray diffraction analysis. The complex [Cu2L2I2], a non-centrosymmetric box dimer, crystallizes in monoclinic C2/c space group and it was found to have distorted square pyramidal geometry (Addison parameter, τ=0.238) with the square basal plane occupied by the thiosemicarbazone moiety and iodine atom whereas the sulfur atom from the other coordinated thiosemicarbazone moiety occupies the apical position. This is the first crystallographically studied system having non-centrosymmetrical entities bridged via thiolate S atoms with Cu(II)I bond. The tridentate thiosemicarbazone coordinates in mono deprotonated thionic tautomeric form in all complexes except in sulfato complex, [Cu(HL)(SO4)]·H2O (1) where it binds to the metal centre in neutral form. The magnetic moment values and the EPR spectral studies reflect the binuclearity of some of the complexes. The spin Hamiltonian and bonding parameters are calculated based on EPR studies. In all the complexes g||>g⊥>2.0023 and the g values in frozen DMF are consistent with the d(x2-y2) ground state. The thermal stabilities of some of the complexes were also determined. PMID:25546494

  14. Synthesis and spectral characterization of mono- and binuclear copper(II) complexes derived from 2-benzoylpyridine-N4-methyl-3-thiosemicarbazone: Crystal structure of a novel sulfur bridged copper(II) box-dimer

    NASA Astrophysics Data System (ADS)

    Jayakumar, K.; Sithambaresan, M.; Aiswarya, N.; Kurup, M. R. Prathapachandra

    2015-03-01

    Mononuclear and binuclear copper(II) complexes of 2-benzoylpyridine-N4-methyl thiosemicarbazone (HL) were prepared and characterized by a variety of spectroscopic techniques. Structural evidence for the novel sulfur bridged copper(II) iodo binuclear complex is obtained by single crystal X-ray diffraction analysis. The complex [Cu2L2I2], a non-centrosymmetric box dimer, crystallizes in monoclinic C2/c space group and it was found to have distorted square pyramidal geometry (Addison parameter, τ = 0.238) with the square basal plane occupied by the thiosemicarbazone moiety and iodine atom whereas the sulfur atom from the other coordinated thiosemicarbazone moiety occupies the apical position. This is the first crystallographically studied system having non-centrosymmetrical entities bridged via thiolate S atoms with Cu(II)sbnd I bond. The tridentate thiosemicarbazone coordinates in mono deprotonated thionic tautomeric form in all complexes except in sulfato complex, [Cu(HL)(SO4)]·H2O (1) where it binds to the metal centre in neutral form. The magnetic moment values and the EPR spectral studies reflect the binuclearity of some of the complexes. The spin Hamiltonian and bonding parameters are calculated based on EPR studies. In all the complexes g|| > g⊥ > 2.0023 and the g values in frozen DMF are consistent with the dx2-y2 ground state. The thermal stabilities of some of the complexes were also determined.

  15. Synthesis and Structure of a Ternary Copper(II) Complex with Mixed Ligands of Diethylenetriamine and Picrate: DNA/Protein-Binding Property and In Vitro Anticancer Activity Studies.

    PubMed

    Shi, Ya-Ning; Zheng, Kang; Zhu, Ling; Li, Yan-Tuan; Wu, Zhi-Yong; Yan, Cui-Wei

    2015-05-01

    Based on the importance of the design and synthesis of transition metal complexes with noncovalent DNA/protein-binding abilities in the field of metallo pharmaceuticals, a new mononuclear ternary copper(II) complex with mixed ligands of diethylenetriamine (dien) and picrate anion (pic), identified as [Cu(dien)(pic)](pic), was synthesized and characterized by elemental analysis, molar conductivity measurement, infrared spectrum, electronic spectral studies, and single-crystal X-ray diffractometry. The structure analysis reveals that the copper(II) complex crystallizes in the monoclinic space group P21 /c, and the copper(II) ion has a distorted square pyramidal coordination geometry. A two-dimensional supramolecular structure is formed through hydrogen bonds. The DNA/bovine serum albumin (BSA)-binding properties of the complex are explored, indicating that the complex can interact with herring sperm DNA via intercalation mode and bind to BSA responsible for quenching of tryptophan fluorescence by static quenching mechanism. The in vitro anticancer activity shows that the copper(II) complex is active against the selected tumor cell lines. PMID:25652782

  16. Synthesis and Structure of a New Copper(II) Coordination Polymer Alternately Bridged by Oxamido and Carboxylate Groups: Evaluation of DNA/BSA Binding and Cytotoxic Activities.

    PubMed

    Jin, Xiao-Ting; Zheng, Kang; Li, Yan-Tuan; Wu, Zhi-Yong; Yan, Cui-Wei

    2015-08-01

    A new one-dimensional (1D) copper(II) coordination polymer {[Cu2 (dmaepox)(dabt)](NO3) · 0.5 H2 O}n , where H3 dmaepox and dabt denote N-benzoato-N'-(3-methylaminopropyl)oxamide and 2,2'-diamino-4,4'-bithiazole, respectively, was synthesized and characterized by single-crystal X-ray diffraction and other methods. The crystal structure analysis revealed that the two copper(II) ions are bridged alternately by cis-oxamido and carboxylato groups to form a 1-D coordination polymer with the corresponding Cu · · · Cu separations of 5.1946(19) and 5.038(2) Å. There is a three-dimensional supramolecular structure constructed by hydrogen bonding and π-π stacking interactions in the crystal. The reactivity towards herring sperm DNA (HS-DNA) and bovine serum albumin (BSA) indicated that the copper(II) polymer can interact with the DNA in the mode of intercalation, and bind to BSA responsible for quenching of tryptophan fluorescence by the static quenching mechanism. The in vitro cytotoxicity suggested that the copper(II) polymer exhibits cytotoxic effects against the selected tumor cell lines. PMID:25940657

  17. Aqueous aerobic oxidation of alkyl arenes and alcohols catalyzed by copper(II) phthalocyanine supported on three-dimensional nitrogen-doped graphene at room temperature.

    PubMed

    Mahyari, Mojtaba; Laeini, Mohammad Sadegh; Shaabani, Ahmad

    2014-07-25

    Copper(ii) tetrasulfophthalocyanine supported on three-dimensional nitrogen-doped graphene-based frameworks was synthesized and introduced as a bifunctional catalyst for selective aerobic oxidation of alkyl arenes and alcohols to the corresponding carbonyl compounds. The ease of catalyst separation, high turnover, low catalyst loading and recyclability could potentially render it applicable in industrial setting. PMID:24912023

  18. Synthesis of mononuclear copper(II) complexes of acyclic Schiff's base ligands: Spectral, structural, electrochemical, antibacterial, DNA binding and cleavage activity

    NASA Astrophysics Data System (ADS)

    Jayamani, Arumugam; Thamilarasan, Vijayan; Sengottuvelan, Nallathambi; Manisankar, Paramasivam; Kang, Sung Kwon; Kim, Young-Inn; Ganesan, Vengatesan

    2014-03-01

    The mononuclear copper(II) complexes (1&2) of ligands L1 [N,N";-bis(2-hydroxy-5-methylbenzyl)-1,4-bis(3-iminopropyl)piperazine] or L2 [N,N";-bis(2-hydroxy-5-bromobenzyl)-1,4-bis(3-iminopropyl) piperazine] have been synthesized and characterised. The single crystal X-ray study had shown that ligands L1 and L2 crystallize in a monoclinic crystal system with P21/c space group. The mononuclear copper(II) complexes show one quasireversible cyclic voltammetric response near cathodic region (-0.77 to -0.85 V) in DMF assignable to the Cu(II)/Cu(I) couple. Binding interaction of the complexes with calf thymus DNA (CT DNA) investigated by absorption studies and fluorescence spectral studies show good binding affinity to CT DNA, which imply both the copper(II) complexes can strongly interact with DNA efficiently. The copper(II) complexes showed efficient oxidative cleavage of plasmid pBR322 DNA in the presence of 3-mercaptopropionic acid as reducing agent through a mechanistic pathway involving formation of singlet oxygen as the reactive species. The Schiff bases and their Cu(II) complexes have been screened for antibacterial activities which indicates that the complexes exhibited higher antimicrobial activity than the free ligands.

  19. Versatility of azide in serendipitous assembly of copper(II) magnetic polyclusters.

    PubMed

    Mukherjee, Sandip; Mukherjee, Partha Sarathi

    2013-11-19

    Engineering at the molecular level is one of the most exciting new developments for the generation of functional materials. However, the concept of designing polynuclear extended structures from bottom up is still not mature. Although progress has been made with secondary building units (SBUs) in metal organic frameworks (MOFs), the control seems to be just an illusion when it comes to bridging ligands such as the azide ion. When we say that the azido ligand is versatile in its bridging capabilities, what we mean is that it would be difficult to predict or control its bridging properties. However, this kind of serendipity is not always bad news. For example, scientists have shown that the azido ligand can mediate magnetic exchanges between paramagnetic metals in a predictable fashion (usually depending upon the bonding geometries). Therefore, it is a well-respected ligand in polynuclear assemblies. Serendipitous assemblies offer new magnetic structures that we may not otherwise even think about synthesizing. The azido ligand forms a variety of complexes with copper(II) using different blocking amines or pyridine based ligands. Its structural nature changes upon changing the substitution on amine, as well as the amount of blocking ligand. In principle, if we take any of these complexes and provide more coordination sites to the bridging azido ligands by removing a fraction of the blocking ligands, we can get new complexes with intricate structural networks and therefore different magnetic properties with the same components as used for the parent complex. In this Account, we mainly discuss the development of a number of new topological and magnetic exchange systems synthesized using this concept. Not all of these new complexes can be grouped according to their basic building structures or even by the ratio of the metal to blocking ligand. Therefore, we divided the discussion by the nuclearity of the basic building structures. Some of the complexes with the same

  20. Spectroscopic, structural and theoretical studies of copper(II) complexes of tridentate NOS Schiff bases

    NASA Astrophysics Data System (ADS)

    Olalekan, Temitope E.; Ogunlaja, Adeniyi S.; VanBrecht, Bernardus; Watkins, Gareth M.

    2016-10-01

    Two newly synthesized Schiff bases (L4 and L5) were derived from the condensation reaction of 2-(methylthiomethyl)anilines and 4-methoxysalicylaldehyde. Coordination complexes of these and four previously reported NOS Schiff bases, Cu(L1)2-Cu(L6)2, were synthesized via the reflux reaction of the various Schiff base ligands with CuCl2·2H2O. The compounds were characterized by means of elemental analysis, FTIR and UV-Vis. The crystal structures of Cu(L1)2 and Cu(L2)2 were obtained by X-ray diffraction. The Schiff bases were coordinated to copper ion as monobasic tridentate ligands through the phenolic oxygen, azomethine nitrogen and thioether sulfur. The microanalyses of the coordination complexes were agreeable with bimolar binding of the ligands to the copper metal ion. The crystal structures of the copper complexes confirmed an octahedral geometry around the metal centre and showed they are mononuclear. The magnetic moment values indicated the presence of a lone electron in each copper(II) orbital and confirmed the mononuclearity of the complexes. The electronic spectra of the coordination compounds consist of the intraligand, charge transfer and d→d bands. Molecular modeling studies on the complexes (Cu(L1)2-Cu(L6)2) by employing DFT revealed that complex Cu(L5)2 possessed the smallest optimization energy as well as a small HOMO-LUMO energy gap which may best explain its higher polarizability as well as reactivity in comparison to the other complexes.

  1. Two unprecedented 1D coordination polymer chains based on tetranuclear copper(II) building blocks

    SciTech Connect

    Li Gaijuan; Xing Yan Song Shuyan; Xu Ning; Liu Xianchun; Su Zhongmin

    2008-09-15

    The reaction of copper(II) sulfate with pyridine in DMF or methanol yield two unprecedented Cu(II) coordination polymers {l_brace}[Cu{sub 4}({mu}{sub 4}-O)(py){sub 4}(SO{sub 4}){sub 4}][{mu}-Cu(py)(DMF){sub 2}]{r_brace}{sub n}(1) and {l_brace}[Cu{sub 4}({mu}{sub 4}-O)(py){sub 4}(SO{sub 4}){sub 4}][{mu}-Cu(py){sub 4}]{r_brace}{sub n}(2), respectively. Single-crystal X-ray diffraction indicated that compound 1 crystallizes in the monoclinic system, space group p2(1)/n, a=14.542(5) A, b=16.359(5) A, c=18.951(5) A, {beta}=92.047(5){sup o}, V=4505(2) A{sup 3}, Z=4 while 2 is monoclinic C2/c, a=23.078(5) A, b=10.214(5) A, c=23.142(5) A, {beta}=115.471(5){sup o}, V=4925(3) A{sup 3}, Z=4. Both of the two compounds consist of tetrahedral tetranuclear [Cu{sub 4}({mu}{sub 4}-O)(py){sub 4}(SO{sub 4}){sub 4}] clusters that are bridged by pentacoordinated Cu atom for 1 or hexacoordinated Cu atoms for 2 through the sulfate oxygen to form the infinite one-dimensional polymer chains. - Graphical abstract: Two unprecedented Cu(II) coordination polymers have been prepared by using solvothermal method; they consist of tetrahedral tetranuclear clusters that are bridged by unique Cu(II) atom through the sulfate oxygen to form the infinite one-dimensional polymer chains (a) for complex 1 and (b) for complex 2.

  2. Synthesis, characterization, DNA-binding and cleavage studies of polypyridyl copper(II) complexes

    NASA Astrophysics Data System (ADS)

    Gubendran, Ammavasi; Rajesh, Jegathalaprathaban; Anitha, Kandasamy; Athappan, Periyakaruppan

    2014-10-01

    Six new mixed-ligand copper(II) complexes were synthesized namely [Cu(phen)2OAc]ClO4ṡH2O(1), [Cu(bpy)2OAc]ClO4ṡH2O(2), [Cu(o-ampacac)(phen)]ClO4(3), [Cu(o-ampbzac)(phen)]ClO4(4), [Cu(o-ampacac)(bpy)]ClO4(5), and [Cu(o-ampbzac)(bpy)]ClO4(6) (phen = 1,10-phenanthroline, bpy = 2, 2‧-bipyridine, o-ampacac = (Z)-4-(2-hydroxylamino)pent-3-ene-2-one,o-ampbzac = (Z)-4-(2-hydroxylamino)-4-phenylbut-3-ene-2-one)and characterized by UV-Vis, IR, EPR and cyclic voltammetry. Ligands were characterized by NMR spectra. Single crystal X-ray studies of the complex 1 shows Cu(II) ions are located in a highly distorted octahedral environment. Absorption spectral studies reveal that the complexes 1-6 exhibit hypochromicity during the interaction with DNA and binding constant values derived from spectral and electrochemical studies indicate that complexes 1, 2 and 3 bind strongly with DNA possibly by an intercalative mode. Electrochemical studies reveal that the complexes 1-4 prefer to bind with DNA in Cu(I) rather than Cu(II) form. The shift in the formal potentials E1/2 and CD spectral studies suggest groove or electrostatic binding mode for the complexes 4-6. Complex 1 can cleave supercoiled (SC) pUC18 DNA efficiently into nicked form II under photolytic conditions and into an open circular form (form II) and linear form (form III) in the presence of H2O2 at pH 8.0 and 37 °C, while the complex 2 does not cleave DNA under similar conditions.

  3. Spectroscopic investigations on partial intercalative binding behaviour of terpyridine based copper(II) complexes with DNA.

    PubMed

    Inamdar, Poonam Rajiv; Sheela, Angappan

    2016-06-01

    Copper based metal complexes have been studied extensively towards DNA interaction aspects, the possible interactions being at the major or minor grooves, intercalation between base pairs, etc. The nature of the ligand decides the binding mode of the complexes thereby exerting different biological significance. Based on this, we have synthesized two mixed ligand copper(II) complexes, [Cu(meFtpy)(bpy)](NO3)2.2(H2O) (1) and [Cu(meFtpy)(phen)](NO3)2.(H2O) (2) based on new furfuryl substituted tertiary pyridine ligand (meFtpy) and ancillary ligands (phen, bpy). They are characterized by UV Visible, FT-IR, (1)H &(13)C NMR and mass spectroscopic techniques. The structures of both the complexes are confirmed by single crystal XRD revealing triclinic crystal system showing penta coordination possessing distorted square pyramidal geometry. The binding ability of the complexes has been explored based on the results of DNA binding studies assessed by different spectroscopic techniques like UV absorption titration, fluorescence displacement assay and circular dicroism and found to show partial intercalative behaviour. The binding constant (Kb) values as obtained from UV absorption titration are found to be 1.29×10(4)M(-1) for 1 and 1.46×10(4)M(-1) for 2 and are compared with the values obtained for doxorubicin, a partial intercalator drug. The binding affinities obtained from absorption titration are found in the order as Kb(doxo)>Kb(2)>Kb(1)>Kb(meFtpy). PMID:27060216

  4. Di- versus Trinuclear Copper(II) Cryptate for the Uptake of Dicarboxylate Anions.

    PubMed

    Esteves, Catarina V; Mateus, Pedro; André, Vânia; Bandeira, Nuno A G; Calhorda, Maria José; Ferreira, Liliana P; Delgado, Rita

    2016-07-18

    Searching for receptors selective for the binding of dicarboxylate anions, the copper(II) complexes of the known ditopic octaazacryptand (t2pN8), derived from bistren [tren = tris(2-aminoethyl)amine] linked by p-xylyl spacers, were re-examined, with the expectation of observing a selective binding of oxalate or malonate by bridging the two copper centers of the [Cu2(t2pN8)(H2O)2](4+) receptor. Solution studies involving the supramolecular species formed by the receptor and oxalate (oxa(2-)), malonate (mal(2-)), and succinate (suc(2-)) anions are reported. The determined association constants revealed the unexpected formation of a 3:1:1 Cu/t2pN8/anion stoichiometry for the cascade species with oxa(2-) and mal(2-), and the single crystal X-ray structural characterization confirmed the presence of tricopper(II) complexes, with an unusual binding mode for the dicarboxylate anions. Each of the two copper atoms binds four nitrogen donor atoms of the t2pN8 cryptand and one additional hydroxide group, which bridges to the third copper. The square planar environment of this one is complete with two oxygen atoms from the oxalate (or the malonate). The two copper centers bound to the tren heads are ∼6.5 Å apart, each one at about 3.5 Å from the third Cu center. These studies were complemented by SQUID magnetization measurements and DFT calculations. The magnetic susceptibility measurements of the oxalate cascade complex showed a strong magnetic coupling (J = - 210 cm(-1)) between the Cu centers at a short distance (3.5 Å), while the coupling between the two equivalent Cu atoms (∼6.5 Å) was only -70 cm(-1). This result was well reproduced by DFT calculations. PMID:27355987

  5. Targeted photocytotoxicity by copper(II) complexes having vitamin B6 and photoactive acridine moieties.

    PubMed

    Mukherjee, Nandini; Podder, Santosh; Banerjee, Samya; Majumdar, Shamik; Nandi, Dipankar; Chakravarty, Akhil R

    2016-10-21

    Copper(II) pyridoxal Schiff base complexes [Cu(L(1)/L(2))(B)]ClO4 (1-4), where HL(1) is 4-(((2-(1H-imidazol-4-yl)ethyl)imino)methyl)-5-(hydroxymethyl)-2-methylpyridin-3-ol (in 1 and 2), HL(2) is 2-(((2-(1H-imidazol-4-yl)ethyl)imino)methyl)phenol (in 3, 4), B is 11-(9-acridinyl)dipyrido[3,2-a:2',3'-c]phenazine (acdppz in 1 and 3), dipyrido[3,2-a:2',3'-c]phenazine (in 2) and 1,10-phenanthroline (in 4), were synthesized, characterized and their photocytotoxicity in visible light, intracellular localization, cellular uptake and DNA photocleavage activity were studied. Complex 4 was characterized by X-ray crystallography. Complexes 1 and 3 having acdppz as photosensitizer showed significant photocytotoxicity in visible light in HeLa and MCF7 cells giving IC50 value of <0.6 μM, while being relatively non-toxic in dark. The complexes were non-toxic to non-tumorigenic HPL1D cells both in light and dark conditions. Complex 1 showed significant localization in the cytoplasm of HeLa cells within 4 h of treatment, as evidenced from confocal microscopy. DCFDA assay on 1 suggested generation of intracellular reactive oxygen species in HeLa cells upon photo-exposure. Importantly, Annexin-V-FITC/PI assay indicated photo-induced apoptotic cell death. PMID:27423638

  6. Superoxidedismutase-mimetic copper(II) complexes containing saccharinate and 4-aminopyridine/4-cyanopyridine.

    PubMed

    Ferrer, Evelina G; Baeza, Natalia; Naso, Luciana G; Castellano, Eduardo E; Piro, Oscar E; Williams, Patricia A M

    2010-01-01

    Two copper(II) complexes, [Cu(sac)(2)(4-cypy)(2)(H(2)O)], 1 and [Cu(sac)(2)(4-Ampy)(2)(H(2)O)], 2 (4-cypy: 4-cyanopyridine; 4-Ampy: 4-aminopyridine) were prepared. Physicochemical properties of the complexes were studied by spectroscopic (solution UV-vis, diffuse reflectance and IR) techniques. Structural X-ray diffraction data could be obtained only for [Cu(sac)(2)(4-cypy)(2)(H(2)O)] that it crystallized in the tetragonal space group P4cc with a=b=15.313(1), c=13.240(1)A, and Z=4 molecules per unit cell. The complex was cited on a crystallographic C(2)-axis with the Cu(II) ion in a square-pyramidal environment, coordinated at the pyramid basis to the nitrogen atom of two saccharine anions [d(Cu-N)=2.011(3)A] and the pyridine N-atom of two 4-cyanopyridine ligands [d(Cu-N)=2.038(4)A]. The coordination was completed by a water molecule at the pyramid apex [d(Cu-Ow)=2.189(5)A]. Elemental and spectroscopic analyses revealed an O-saccharinate coordination mode for complex 2 and a square-pyramidal structure. Only complex 2 retained its structure in methanolic solution. However, both complexes were able to catalyze the dismutation of superoxide anion (O(2)(-)) (pH 7.5) at micromolar concentrations. Therefore, these complexes behaved as useful SOD-mimetic compounds. PMID:20122575

  7. Selective transport of copper(I, II), cadmium(II), and zinc(II) ions through a supported liquid membrane containing bathocuproine, neocuproine, or bathophenanthroline

    SciTech Connect

    Saito, Takashi )

    1994-06-01

    Some selective transport systems for heavy metallic ions through a supported liquid membrane (SLM) containing a 2,2[prime]-dipyridyl derivative ligand, 4,7-diphenyl-2,9-dimethyl-1, 10-phenanthroline (bathocuproine), 2,9-dimethyl-1,10-phenanthroline (neocuproine), or 4,7-diphenyl-1,10-phenanthroline (bathophenanthroline), were investigated. The transport of copper(I, II), cadmium(II), zinc(II), lead(II), and cobalt(II) ions was accomplished with a halogen ion such as chloride, bromide, or iodide ion as a pairing ion species for any SLM. The ranking of the permeability of the metallic ions was Cu[sup +,2+], Zn[sup 2+], Cd[sup 2+] [much gt] Pb[sup 2+], Co[sup 2+]. When the oxidation-reduction potential gradient was used as a driving force for metallic ions, the transport of Cu[sup +] ions was higher than those of Cd[sup 2+] and Zn[sup 2+] ions for any SLM containing bathocuproine, neocuproine, or bathophenanthroline. On the other hand, in the transport system which used the concentration gradient of pairing ion species, the permeability of the Cu[sup 2+] ion decreased whereas that of the Cd[sup 2+] ion increased. Moreover, it was found that the different selectivity for the transport of metallic ions is produced by using various pairing ion species. 18 refs., 9 figs.

  8. Novel Zinc(II) Complexes [Zn(atc-Et)2] and [Zn(atc-Ph)2]: In Vitro and in Vivo Antiproliferative Studies

    PubMed Central

    Lopes, Erica de O.; de Oliveira, Carolina G.; da Silva, Patricia B.; Eismann, Carlos E.; Suárez, Carlos A.; Menegário, Amauri A.; Leite, Clarice Q. F.; Deflon, Victor M.; Pavan, Fernando R.

    2016-01-01

    Cisplatin and its derivatives are the main metallodrugs used in cancer therapy. However, low selectivity, toxicity and drug resistance are associated with their use. The zinc(II) (ZnII) thiosemicarbazone complexes [Zn(atc-Et)2] (1) and [Zn(atc-Ph)2] (2) (atc-R: monovalent anion of 2-acetylpyridine N4-R-thiosemicarbazone) were synthesized and fully characterized in the solid state and in solution via elemental analysis, Fourier transform infrared (FTIR), ultraviolet-visible (UV-Vis) and proton nuclear magnetic resonance (1H NMR) spectroscopy, conductometry and single-crystal X-ray diffraction. The cytotoxicity of these complexes was evaluated in the HepG2, HeLa, MDA-MB-231, K-562, DU 145 and MRC-5 cancer cell lines. The strongest antiproliferative results were observed in MDA-MB-231 and HepG2 cells, in which these complexes displayed significant selective toxicity (3.1 and 3.6, respectively) compared with their effects on normal MRC-5 cells. In vivo studies were performed using an alternative model (Artemia salina L.) to assure the safety of these complexes, and the results were confirmed using a conventional model (BALB/c mice). Finally, tests of oral bioavailability showed maximum plasma concentrations of 3029.50 µg/L and 1191.95 µg/L for complexes 1 and 2, respectively. According to all obtained results, both compounds could be considered as prospective antiproliferative agents that warrant further research. PMID:27213368

  9. Spectral characterization of novel ternary zinc(II) complexes containing 1,10-phenanthroline and Schiff bases derived from amino acids and salicylaldehyde-5-sulfonates

    NASA Astrophysics Data System (ADS)

    Boghaei, Davar M.; Gharagozlou, Mehrnaz

    2007-07-01

    A series of new ternary zinc(II) complexes [Zn(L 1-10)(phen)], where phen is 1,10-phenanthroline and H 2L 1-10 = tridentate Schiff base ligands derived from the condensation of amino acids (glycine, L-phenylalanine, L-valine, L-alanine, and L-leucine) and salicylaldehyde-5-sulfonates (sodium salicylaldehyde-5-sulfonate and sodium 3-methoxy-salicylaldehyde-5-sulfonate), have been synthesized. The complexes were characterized by elemental analysis, IR, UV-vis, 1H NMR, and 13C NMR spectra. The IR spectra of the complexes showed large differences between νas(COO) and νs(COO), Δ ν ( νas(COO) - νs(COO)) of 191-225 cm -1, indicating a monodentate coordination of the carboxylate group. Spectral data showed that in these ternary complexes the zinc atom is coordinated with the Schiff base ligand acts as a tridentate ONO moiety, coordinating to the metal through its phenolic oxygen, imine nitrogen, and carboxyl oxygen, and also with the neutral planar chelating ligand, 1,10-phenanthroline, coordinating through nitrogens.

  10. Synthesis, spectral characterization and biological activity of zinc(II) complexes with 3-substituted phenyl-4-amino-5-hydrazino-1, 2, 4-triazole Schiff bases

    NASA Astrophysics Data System (ADS)

    Singh, A. K.; Pandey, O. P.; Sengupta, S. K.

    New Zn(II) complexes have been synthesized by the reactions of zinc(II) acetate with Schiff bases derived from 3-substituted phenyl-4-amino-5-hydrazino-1, 2, 4-triazole and benzaldehyde, 2-hydroxyacetophenone or indoline-2,3-dione. All these complexes are soluble in DMF and DMSO; low molar conductance values indicate that they are non-electrolytes. Elemental analyses suggest that the complexes have 1:1 stoichiometry of the type [ZnL(H 2O) 2], [ZnL'(OAc) 2(H 2O) 2] (L = dianionic Schiff bases derived from 3-(substituted phenyl)-4-amino-5-hydrazino-1, 2, 4-triazole and 2-hydroxyacetophenone or indoline-2,3-dione; L' = neutral Schiff bases derived from 3-(substituted phenyl)-4-amino-5-hydrazino-1, 2, 4-triazole and benzaldehyde) and they were characterized by FT-IR, 1H NMR, 13C NMR and FAB mass. All these Schiff bases and their complexes have also been screened for their antibacterial activities against Bacillus subtilis, Escherichia coli and antifungal activities against Colletotrichum falcatum, Aspergillus niger, Fusarium oxysporium and Carvularia pallescence by petriplates methods.

  11. Novel Zinc(II) Complexes [Zn(atc-Et)₂] and [Zn(atc-Ph)₂]: In Vitro and in Vivo Antiproliferative Studies.

    PubMed

    Lopes, Erica de O; Oliveira, Carolina G de; Silva, Patricia B da; Eismann, Carlos E; Suárez, Carlos A; Menegário, Amauri A; Leite, Clarice Q F; Deflon, Victor M; Pavan, Fernando R

    2016-01-01

    Cisplatin and its derivatives are the main metallodrugs used in cancer therapy. However, low selectivity, toxicity and drug resistance are associated with their use. The zinc(II) (Zn(II)) thiosemicarbazone complexes [Zn(atc-Et)₂] (1) and [Zn(atc-Ph)₂] (2) (atc-R: monovalent anion of 2-acetylpyridine N4-R-thiosemicarbazone) were synthesized and fully characterized in the solid state and in solution via elemental analysis, Fourier transform infrared (FTIR), ultraviolet-visible (UV-Vis) and proton nuclear magnetic resonance (¹H NMR) spectroscopy, conductometry and single-crystal X-ray diffraction. The cytotoxicity of these complexes was evaluated in the HepG2, HeLa, MDA-MB-231, K-562, DU 145 and MRC-5 cancer cell lines. The strongest antiproliferative results were observed in MDA-MB-231 and HepG2 cells, in which these complexes displayed significant selective toxicity (3.1 and 3.6, respectively) compared with their effects on normal MRC-5 cells. In vivo studies were performed using an alternative model (Artemia salina L.) to assure the safety of these complexes, and the results were confirmed using a conventional model (BALB/c mice). Finally, tests of oral bioavailability showed maximum plasma concentrations of 3029.50 µg/L and 1191.95 µg/L for complexes 1 and 2, respectively. According to all obtained results, both compounds could be considered as prospective antiproliferative agents that warrant further research. PMID:27213368

  12. Mono- and tetra-substituted zinc(II) phthalocyanines containing morpholinyl moieties: Synthesis, antifungal photodynamic activities, and structure-activity relationships.

    PubMed

    Zheng, Bi-Yuan; Ke, Mei-Rong; Lan, Wen-Liang; Hou, Lu; Guo, Jun; Wan, Dong-Hua; Cheong, Ling-Zhi; Huang, Jian-Dong

    2016-05-23

    A series of zinc(II) phthalocyanines (ZnPcs) mono-substituted and tetra-substituted with morpholinyl moieties and their quaternized derivatives have been synthesized and evaluated for their antifungal photodynamic activities toward Candida albicans. The α-substituted, quaternized, and mono-substituted ZnPcs are found to have higher antifungal photoactivity than β-substituted, neutral, and tetra-substituted counterparts. The cationic α-mono-substituted ZnPc (6a) exhibits the highest photocytotoxicity. Moreover, it is more potent than axially di-substituted analogue. The different photocytotoxicities of these compounds have also been rationalized by investigating their spectroscopic and photochemical properties, aggregation trend, partition coefficients, and cellular uptake. The IC90 value of 6a against C. albicans cells is as low as 3.3 μM with a light dose of 27 J cm(-2), meaning that 6a is a promising candidate as the antifungal photosensitizer for future investigations. PMID:27046231

  13. New tridentate azo-azomethines and their copper(II) complexes: Synthesis, solvent effect on tautomerism, electrochemical and biological studies

    NASA Astrophysics Data System (ADS)

    Sarigul, Munire; Deveci, Pervin; Kose, Muhammet; Arslan, Ugur; Türk Dagi, Hatice; Kurtoglu, Mukerrem

    2015-09-01

    In this study, three azo-azomethines and their copper(II) complexes were prepared and characterized by analytical and spectroscopic methods. The complexes prepared were found to be mononuclear and the chelation of the ligands to the copper(II) ions occurs through two phenolic oxygens and a nitrogen atom of the azomethine group of the ligand. The tautomeric behaviors of the azo-azomethines in solution were studied by UV-Vis. spectra in three organic solvents with different polarity (CHCl3, DMSO and DMF) at room temperature. The redox behaviors of the azo-azomethines and their Cu(II) complexes were investigated by cyclic voltammetry (CV) in DMSO solution containing 0.1 M tetrabutylammonium tetrafluoroborate (TBATFB) as supporting electrolyte. Additionally, the antibacterial activity was also evaluated by the broth microdilution methods against Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa. The compounds were found to be less effective against all bacteria tested than two reference antibiotics (ampicillin and gentamicin).

  14. Use of water-soluble PbS quantum dots as fluorescent probe in sensing copper(II)

    NASA Astrophysics Data System (ADS)

    Li, Ting; Wang, Nanxi; Chen, Lijia; Deng, Dawei; Gu, Yueqing

    2010-11-01

    In this paper, we report a new facile method for the synthesis of water-soluble PbS quantum dots (QDs), using dihydrolipoic acid (DHLA) as a stabilizer. The prepared QDs were characterized by optical techniques and high-resolution transmission electron microscopy (TEM). Next, these water-soluble luminescent PbS QDs were further used to detect copper (II). The obtained experimental results show that the fluorescence of the PbS QDs could be markedly quenched by Cu(II) whereas approximate concentrations of other physiologically relevant cations, such as Zn(II), Ca(II), Mg(II), Mn(II), Na(I) and K(I) etc., almost did not interfere with the fluorescence quenching progress of copper ions. Based on this, a simple and rapid method for Cu(II) determination was developed. Under optimal conditions, the response was linearly proportional to the copper(II) concentration in the range of 1 to 11.5x10-8 mol•L-1, with a correlation coefficient of 0.995. Hence, aqueous DHLA-stabilized PbS QDs may be a promising fluorescent probe in sensing copper(II) selectively.

  15. Thermodynamic and Structural Characterization of the Copper(II) Complexes of Peptides Containing Both Histidyl and Aspartyl Residues

    PubMed Central

    Kállay, Csilla; Nagy, Zoltán; Várnagy, Katalin; Malandrinos, Gerasimos; Hadjiliadis, Nick; Sóvágó, Imre

    2007-01-01

    Terminally protected pentapeptides with 2 histidines (Ac-HHVGD-NH2 and Ac-HVGDH-NH2) and the terminally free peptides containing both internal aspartyl and C-terminal histidyl residues (FDAH and VIDAH) have been synthesized, and copper(II) complexes studied by potentiometric, UV-Vis, CD, and EPR spectroscopic techniques in solution. Both thermodynamic and spectroscopic data reveal that side chain donor atoms of aspartyl and histidyl residues have a significant contribution to the metal binding affinity of peptide molecules. In the case of terminally protected peptides, the role of the imidazole-N donor functions is reflected in the enhanced stability of the 3N and 4N coordinated copper(II) complexes. The amino and β-carboxylate groups of FDAH and VIDAH create a very effective metal binding site with the (NH2, N−, β-COO−) and (NH2, N−, N−, β-COO−) coordination modes including the N-termini, while the histidine sites are available for the formation of the (Nim, N−, N−) binding mode resulting in the preference of dinuclear complex formation. PMID:18273380

  16. Sorption of copper(II) ion from aqueous solution by Tectona grandis l.f. (teak leaves powder).

    PubMed

    King, P; Srinivas, P; Kumar, Y Prasanna; Prasad, V S R K

    2006-08-25

    Studies on a batch sorption system using Tectona grandis l.f. as adsorbent was investigated to remove copper(II) from aqueous solutions. The adsorption experiments were performed under various conditions such as different initial concentrations, pH, adsorbent dosage and adsorbent particle size. The data showed that 0.1 g of Tectona grandis l.f. was found to remove 71.66% of 20 mg/L copper(II) from 30 mL aqueous solution in 180 min. The experimental equilibrium data were adjusted by the adsorption isotherms from Langmuir and Freundlich models and their equilibrium parameters were determined. The best-adjusted model to the experimental equilibrium data for Tectona grandis l.f. was the Langmuir model. Using the Langmuir model equation, the monolayer sorption capacity of Tectona grandis l.f. was evaluated and found to be 95.40 mg/g. The optimum pH value was found to be 5.5. The pseudo-first-order and pseudo-second-order kinetic models were used to describe the kinetic data. The dynamic data fitted the pseudo-second-order kinetic model. PMID:16443324

  17. Structural Diversity of Copper(II) Complexes with 9-Deazahypoxanthine and Their in Vitro SOD-Like Activity

    PubMed Central

    Gáliková, Jana; Trávníček, Zdeněk

    2015-01-01

    Two structurally different copper(II) complexes of the compositions [{Cu(9dhx)(H2O)3}2(µ-SO4)2] (1) and [Cu(9dhx)2(H2O)2(NO3)2]·H2O (2), involving 9-deazahypoxanthine (9dhx; 6-oxo-9-deazapurine; 9-deazahypoxanthine), have been prepared and characterized by elemental analysis, infrared and electronic spectroscopy, electrospray ionisation (ESI) mass spectrometry, thermogravimetric (TG) and differential thermal (DTA) analyses, and cyclic voltammetry. The X-ray structures of complexes 1 and [Cu(9dhx)2(H2O)2(NO3)2] (2a) revealed the distorted octahedral geometry in the vicinity of the copper(II) atoms, with the NO5 and N2O4 donor set, respectively. In the dimeric compound 1, the {Cu(9dhx)(H2O)3}2 units are bridged by sulfate groups with the Cu···Cu separation being 5.3446(2) Å. In both structures the 9dhx ligands are coordinated through the N3 atoms of the pyrimidine moieties. The SOD-like activity of complexes 1 and 2 was evaluated in vitro showing moderate effect, with the IC50 values equal to 18.20, and 53.33 μM, respectively. PMID:26184182

  18. Structural Diversity of Copper(II) Complexes with 9-Deazahypoxanthine and Their in Vitro SOD-Like Activity.

    PubMed

    Gáliková, Jana; Trávníček, Zdeněk

    2015-01-01

    Two structurally different copper(II) complexes of the compositions [{Cu(9dhx)(H2O)3}2(µ-SO4)2] (1) and [Cu(9dhx)2(H2O)2(NO3)2]·H2O (2), involving 9-deazahypoxanthine (9dhx; 6-oxo-9-deazapurine; 9-deazahypoxanthine), have been prepared and characterized by elemental analysis, infrared and electronic spectroscopy, electrospray ionisation (ESI) mass spectrometry, thermogravimetric (TG) and differential thermal (DTA) analyses, and cyclic voltammetry. The X-ray structures of complexes 1 and [Cu(9dhx)2(H2O)2(NO3)2] (2a) revealed the distorted octahedral geometry in the vicinity of the copper(II) atoms, with the NO5 and N2O4 donor set, respectively. In the dimeric compound 1, the {Cu(9dhx)(H2O)3}2 units are bridged by sulfate groups with the Cu···Cu separation being 5.3446(2) Å. In both structures the 9dhx ligands are coordinated through the N3 atoms of the pyrimidine moieties. The SOD-like activity of complexes 1 and 2 was evaluated in vitro showing moderate effect, with the IC50 values equal to 18.20, and 53.33 μM, respectively. PMID:26184182

  19. Synthesis, superoxide dismutase, nuclease, and anticancer activities of copper(II) complexes incorporating bis(2-picolyl)amine with different counter anions

    NASA Astrophysics Data System (ADS)

    Ibrahim, Mohamed M.; Ramadan, Abdel-Motaleb M.; Mersal, Gaber A. M.; El-Shazly, Samir A.

    2011-07-01

    Interaction of the tridentate ligand bis(2-picolyl)amine L with copper(II) salts gave a series of copper(II) complexes with the formula types: [ LCu(X) 2] (X = Cl -1, = Br -2), [( LCu (H 2O)(μ-SO 4)( LCu(H 2O)]SO 43, [ LCu(OAc)](OAc )H 2O 4, [ LCu(H 2O) 2](Y) 2 (Y = NO3-5, = ClO4-6). Their structures and properties were characterized by elemental analysis, thermal analysis (TGA), IR, UV-vis and ESR spectroscopy, electrochemical measurements including cyclic voltammetry and electrical molar conductivity, and magnetic moment measurements. A square pyramidal geometry is proposed for the halogeno complexes 1 and 2 in monomeric structures. For sulfate complex, the sulfate group bridged two copper(II) ions of the two [N 3O] donor units to give the dimeric complex molecule 3 in square pyramidal environment around the copper(II) ions. In the case of complexes 4- 6, square planar stereochemistries in monomeric structures are suggested. The SOD biomimetic catalytic activity of the obtained complexes was assessed for their ability to inhibit the reduction of nitroblue tetrazolium (NBT). The catalytic efficiency of O2- scavenging by complexes depends on the nature of the particular acidic anion radical incorporated in the complex molecule and follows the order: NO3- > ClO4- > Br - ⩾ Cl - > SO4- > AcO -. A probable mechanistic implications for the catalytic dismutation of O2- by copper(II) complexes are proposed. Furthermore, complex 1 exhibits significant hydrolytic cleavage of the genomic DNA in the absence of any external additives. In addition, the in vitro study of cytotoxicity of complex 1 on colon cancer cell line (Caco-2) indicates that the complex has the potential to act as an effective anticancer drug with IC 50 value of 156 ± 0.35 μM.

  20. A three-dimensional metal-organic framework with a pcu net constructed by zinc(II)/3-amino-1,2,4-triazole layer and an inorganic sulfate pillar

    NASA Astrophysics Data System (ADS)

    Lin, Jian-Di; Huang, Zhi-Jian; Xie, Yong-Ping; Li, Qing-Lu

    2015-03-01

    Hydrothermal reaction of ZnSO4·7H2O and 3-amino-1H-1,2,4-triazole (HATRZ) led to a three-dimensional zinc(II) coordination polymer, Zn2(ATRZ)2SO4·3H2O (1). Compound 1 has been fully characterized by single crystal and powder X-ray diffraction, thermogravimetric analysis, infrared spectroscopy and elemental analysis. Single crystal X-ray diffraction reveals that 1 is a pcu-like network metal-organic framework which is constructed by a zinc(II)/ATRZ layer and a rarely reported inorganic sulfate pillar. Moreover, 1 shows characteristic ligand-centered fluorescence property.

  1. Di-, tri-, and tetranuclear nickel(II) complexes with oximato bridges: magnetism and catecholase-like activity of two tetranuclear complexes possessing rhombic topology.

    PubMed

    Das, Lakshmi Kanta; Biswas, Apurba; Kinyon, Jared S; Dalal, Naresh S; Zhou, Haidong; Ghosh, Ashutosh

    2013-10-21

    Oxime-based tridentate Schiff base ligands 3-[2-(diethylamino)ethylimino]butan-2-one oxime (HL(1)) and 3-[3-(dimethylamino)propylimino]butan-2-one oxime (HL(2)) produced the dinuclear complex [Ni2L(1)2](ClO4)2 (1) and trinuclear complex [Ni3(HL(2))3(μ3-O)](ClO4)4·CH3CN (2), respectively, upon reaction with Ni(ClO4)2·6H2O. However, in a slightly alkaline medium, both of the ligands underwent hydrolysis and resulted in tetranuclear complexes [{Ni(deen)(H2O)}2(μ3-OH)2{Ni2(moda)4}](ClO4)2·2CH3CN (3) and [{Ni(dmpn)(CH3CN)2}2(μ3-OH)2{Ni2(moda)4}](ClO4)2·CH3CN (4), where deen = 2-(diethylamino)ethylamine, dmpn = 3-(dimethylamino)-1-propylamine, and modaH = diacetyl monoxime. All four complexes have been structurally characterized. Complex 1 is a centrosymmetric dimer where the square planar nickel(II) atoms are joined solely by the oximato bridges. In complex 2, three square planar nickel atoms form a triangular core through a central oxido (μ3-O) and peripheral oximato bridges. Tetranuclear complexes 3 and 4 consist of four distorted octahedral nickel(II) ions held together in a rhombic chair arrangement by two central μ3-OH and four peripheral oximato bridges. Magnetic susceptibility measurements indicated that dinuclear 1 and trinuclear 2 exhibited diamagnetic behavior, while tetranuclear complexes 3 and 4 were found to have dominant antiferromagnetic intramolecular coupling with concomitant ferromagnetic interactions. Despite its singlet ground state, both 3 and 4 serve as useful examples of Kahn's model for competing spin interactions. High-frequency EPR studies were also attempted, but no signal was detected, likely due to the large energy gap between the ground and first excited state. Complexes 3 and 4 exhibited excellent catecholase-like activity in the aerial oxidation of 3,5-di-tert-butylcatechol to the corresponding o-quinone, whereas 1 and 2 did not show such catalytic activity. Kinetic data analyses of this oxidation reaction in acetonitrile

  2. Synthesis and Ligand Non-Innocence of Thiolate-Ligated (N4S) Iron(II) and Nickel(II) Bis(imino)pyridine Complexes

    PubMed Central

    Widger, Leland R.; Jiang, Yunbo; Siegler, Maxime; Kumar, Devesh; Latifi, Reza; de Visser, Sam P.; Jameson, Guy N.L.; Goldberg, David P.

    2013-01-01

    The known iron(II) complex [FeII(LN3S)(OTf)] (1) was used as starting material to prepare the new biomimetic (N4S(thiolate)) iron(II) complexes [FeII(LN3S)(py)](OTf) (2) and [FeII(LN3S)(DMAP)](OTf) (3), where LN3S is a tetradentate bis(imino)pyridine (BIP) derivative with a covalently tethered phenylthiolate donor. These complexes were characterized by X-ray crystallography, UV-vis, 1H NMR, and Mössbauer spectroscopy, as well as electrochemistry. A nickel(II) analogue, [NiII(LN3S)](BF4) (5), was also synthesized and characterized by structural and spectroscopic methods. Cyclic voltammetric studies showed 1 – 3 and 5 undergo a single reduction process with E1/2 between −0.9 to −1.2 V versus Fc+/Fc. Treatment of 3 with 0.5% Na/Hg amalgam gave the mono-reduced complex [Fe(LN3S)(DMAP)]0 (4), which was characterized by X-ray crystallography, UV-vis, EPR (g = [2.155, 2.057, 2.038]) and Mössbauer (δ = 0.33 mm s−1; ΔEQ = 2.04 mm s−1) spectroscopies. Computational methods (DFT) were employed to model complexes 3 – 5. The combined experimental and computational studies show that 1 – 3 are 5-coordinate, high-spin (S = 2) FeII complexes, whereas 4 is best described as a 5-coordinate, intermediate-spin (S = 1) FeII complex antiferromagnetically coupled to a ligand radical. This unique electronic configuration leads to an overall doublet spin (Stotal = ½) ground state. Complexes 2 and 3 are shown to react with O2 to give S-oxygenated products, as previously reported for 1. In contrast, the mono-reduced 4 appears to react with O2 to give a mixture of S- and Fe-oxygenates. The nickel(II) complex 5 does not react with O2, and even when the mono-reduced nickel complex is produced, it appears to undergo only outer-sphere oxidation with O2. PMID:23992096

  3. Synthesis, spectroscopic characterization and electrochemical studies of Girard's T chromone complexes

    NASA Astrophysics Data System (ADS)

    Al-Saeedi, Sameerah I.; Alaghaz, Abdel-Nasser M. A.; Ammar, Reda A.

    2016-05-01

    Complexes of cobalt(II), nickel(II), copper(II) and zinc(II) of general composition [M(L)2] have been. The elemental analyses, molar conductance, spectral, magnetic moment and thermal measurements studies of the compounds led to the conclusion that the ligand acts as a tridentate manner (OON). The molar conductance of the metal complexes in fresh solution of DMSO lies in the range of 8.10-10.18 Ω-1 cm2 mol-1 indicating their non-electrolytic behavior. On the basis of analytical and spectroscopic techniques, octahedral geometry of the complexes was proposed. The ligand field parameters were calculated for Co(II), Ni(II) and Cu(II) complexes and their values were found in the range reported for a octahedral structure. The data show that the complexes have composition of ML2 type. The activation of thermodynamic parameters are calculated using different equations. The octahedral geometry of the complexes is confirmed using DFT method from DMOL3 calculations and ligand field parameters. The cyclic voltammograms of the Cu(II)/Co(II)/Ni(II) complexes investigated in DMSO solution exhibit metal centered electroactivity in the potential range -1.5 to +1.5 V. The electrochemical data obtained for Cu(II) complexes explains the change of structural arrangement of the ligand around Cu(II) ions.

  4. Spectroscopic investigations of new binuclear transition metal complexes of Schiff bases derived from 4,6-diacetylresorcinol and 3-amino-1-propanol or 1,3-diamino-propane

    NASA Astrophysics Data System (ADS)

    Emara, Adel A. A.; Saleh, Akila A.; Adly, Omima M. I.

    2007-11-01

    The bifunctional carbonyl compound; 4,6-diacetylresorcinol (DAR) serves as precursor for the formation of different Schiff base ligands, which are either di- or tetra-basic with two symmetrical sets of either O 2N or N 2O tridentate chelating sites. The condensation of 4,6-diacetylresorcinol with 3-amino-1-propanol (3-AP) or 1,3-diaminopropane (DAP), yields the corresponding hexadentate Schiff base ligands, abbreviated as H 4L a and H 2L b, respectively. The structures of these ligands were elucidated by elemental analyses, IR, mass, 1H NMR and electronic spectra. Reaction of the Schiff base ligands with copper(II), nickel(II), cobalt(II), zinc(II), cadmium(II), iron(III), chromium(III), vanadyl(IV) and uranyl(VI) ions in 1:2 molar ratio afforded the corresponding transition metal complexes. A variety of binuclear complexes for the metal complexes were obtained with the ligands in its di- or tetra-deprotonated forms. The structures of the newly prepared complexes were identified by elemental analyses, infrared, electronic, mass, 1H NMR and ESR spectra as well as magnetic susceptibility measurements and thermal gravimetric analysis (TGA). The bonding sites are the azomethine and amino nitrogen atoms, and phenolic and alcoholic oxygen atoms. The metal complexes exhibit different geometrical arrangements such as square planar, tetrahedral, square pyramid and octahedral arrangement.

  5. Monitoring of trace amounts of heavy metals in different food and water samples by flame atomic absorption spectrophotometer after preconcentration by amine-functionalized graphene nanosheet.

    PubMed

    Behbahani, Mohammad; Tapeh, Nasim Akbari Ghareh; Mahyari, Mojtaba; Pourali, Ali Reza; Amin, Bahareh Golrokh; Shaabani, Ahmad

    2014-11-01

    We are introducing graphene oxide modified with amine groups as a new solid phase for extraction of heavy metal ions including cadmium(II), copper(II), nickel(II), zinc(II), and lead(II). Effects of pH value, flow rates, type, concentration, and volume of the eluent, breakthrough volume, and the effect of potentially interfering ions were studied. Under optimized conditions, the extraction efficiency is >97 %, the limit of detections are 0.03, 0.05, 0.2, 0.1, and 1 μg L(-1) for the ions of cadmium, copper, nickel, zinc, and lead, respectively, and the adsorption capacities for these ions are 178, 142, 110, 125, and 210 mg g(-1). The amino-functionalized graphene oxide was characterized by thermogravimetric analysis, transmission electron microscopy, scanning electron microscopy, and Fourier transform infrared spectrometry. The proposed method was successfully applied in the analysis of environmental water and food samples. Good spiked recoveries over the range of 95.8-100.0 % were obtained. This work not only proposes a useful method for sample preconcentration but also reveals the great potential of modified graphene as an excellent sorbent material in analytical processes. PMID:25023747

  6. Synthesis, spectroscopic studies and inhibitory activity against bactria and fungi of acyclic and macrocyclic transition metal complexes containing a triamine coumarine Schiff base ligand

    NASA Astrophysics Data System (ADS)

    Abou-Hussein, A. A.; Linert, Wolfgang

    2015-04-01

    Two series of new mono and binuclear complexes with a Schiff base ligand derived from the condensation of 3-acetylcoumarine and diethylenetriamine, in the molar ratio 2:1 have been prepared. The ligand was characterized by elemental analysis, IR, UV-visible, 1H-NMR and mass spectra. The reaction of the Schiff base ligand with cobalt(II), nickel(II), copper(II), zinc(II) and oxovanadium(IV) lead to mono or binuclear species of cyclic or macrocyclic complexes, depending on the mole ratio of metal to ligand and as well as on the method of preparation. The Schiff base ligand behaves as a cyclic bidentate, tetradendate or pentaentadentae ligand. The formation of macrocyclic complexes depends significantly on the dimension of the internal cavity, the rigidity of the macrocycles, the nature of its donor atoms and on the complexing properties of the anion involved in the coordination. Electronic spectra and magnetic moments of the complexes indicate that the geometries of the metal centers are either square pyramidal or octahedral for acyclic or macro-cyclic complexes. The structures are consistent with the IR, UV-visible, ESR, 1H-NMR, mass spectra as well as conductivity and magnetic moment measurements. The Schiff base ligand and its metal complexes were tested against two pathogenic bacteria as Gram-positive and Gram-negative bacteria as well as one kind of fungi. Most of the complexes exhibit mild antibacterial and antifungal activities against these organisms.

  7. Reversible oxidation and rereduction of entire thin films of transition-metal phthalocyanines

    SciTech Connect

    Green, J.M.; Faulkner, L.R.

    1983-05-18

    Thin films (1000 to 2000A thick) of iron(II) (Fe), cobalt(II) (Co), nickel(II) (Ni), copper(II) (Cu), and zinc(II) (Zr) phthalocyanines (Pc) on gold or indium oxide electrodes undergo stoichiometric oxidation and rereduction. Except for FePc and CoPc, the process is essentially reversible. Chronocoulometry showed that ZnPc films oxidized to the extent of 1.21 electrons per ZnPc molecule; CoPc required 1.92 electrons per molecule. Charge compensation is attained upon oxidation by uptake of anions from the electrolyte and by expulsion of anions upon reduction. Auger electron spectrometry allowed detection of the ions and characterization of their distributions. In partially oxidized films, the anions appear to be homogeneously distributed. Oxidation seems to proceed at all grains with equal probability, with anions entering and departing along grain boundaries. Smaller anions allow full oxidation at rapid rates; larger ones inhibit the oxidation with respect to rate. Optical spectroscopy showed evidence for reorganizaton of the crystalline lattices. The rereduced form is not the same as the original material, but it can be restored to the original form by annealing at 125/sup 0/C. In cyclic oxidations and rereductions, there is a gradual loss of charge-consuming ability, apparently related to electrical isolation of small domains, perhaps grains. The oxidations and rereductions are electrochromic, and the various color changes are described. 10 figures, 1 table.

  8. Study of the ligands involved in metal binding to alfalfa biomass

    SciTech Connect

    Tiemann, K.J.; Gardea-Torresdey, J.L.; Sias, S.; Gamez, G.; Rodriguez, O.; Renner, M.W.; Furenlid, L.R.

    1997-12-31

    Previously performed studies have shown that the alfalfa shoot biomass can bind an appreciable amount of copper(II), nickel(II), cadmium(II), chromium(III), lead(II), and zinc(II) ions from aqueous solution. Of the seven different alfalfa populations studied, Malone and African demonstrated the highest capacity for metal binding. Laboratory experiments were performed to determine the pH profiles, time dependency, capacity for metal binding, as well as the recovery of the metals bound. For most of the metal ions studied, the biomass showed a high affinity for metal binding around pH 5.0 within a short time period. Binding capacity experiments revealed the following amounts of metal ions bound per gram of biomass: 19.7 mg Cu(II), 4.11 mg Ni(II), 7.1 mg Cd(II), 7.7 mg Cr(III), 43 mg Pb(II), and 4.9 mg Zn(II). Most of these metals were recovered from the biomass by treatment with 0.1 M HCl with the exception of Cr(III). Because no Cr(VI) binding occurred, none was recovered. Direct and indirect approaches were applied to study the possible mechanisms involved in metal binding by the alfalfa biomass. The direct approach involves investigations of the alfalfa shoot biomass by X-ray absorption spectroscopy analysis (XANES and EXAFS), which were performed at Brookhaven National Laboratory.

  9. Synthesis, spectral and magnetic studies of mono- and bi-nuclear metal complexes of a new bis(tridentate NO2) Schiff base ligand derived from 4,6-diacetylresorcinol and ethanolamine

    NASA Astrophysics Data System (ADS)

    Shebl, Magdy

    2009-07-01

    A new bis(tridentate NO2) Schiff base ligand, H4L, was prepared by the reaction of the bifunctional carbonyl compound; 4,6-diacetylresorcinol (DAR) with ethanolamine. The ligand reacted with iron(III), cobalt(II), nickel(II), copper(II), zinc(II), cadmium(II), cerium(III) and uranyl(VI) ions, in absence and in presence of LiOH, to yield mono- and bi-nuclear complexes with different coordinating sites. The ligand and its metal complexes were characterized by elemental analyses, IR, 1H NMR, electronic, ESR and mass spectra, conductivity and magnetic susceptibility measurements as well as thermal analyses. In absence of LiOH, mononuclear complexes (2, 3 and 5-9) as well as binuclear complexes (1 and 4) were obtained. In mononuclear complexes, the ligand acted as a neutral, mono- and di-basic/bi- and tetra-dentate ligand while in binuclear complexes (1 and 4), the ligand acted as a bis(mono- or di-basic/tridentate) ligand. On the other hand, in presence of LiOH, only binuclear complexes (10-15) were obtained in which the ligand acted as a bis(dibasic tridentate) ligand. The metal complexes exhibited different geometrical arrangements such as octahedral, tetrahedral, square planar, square pyramidal and pentagonal bipyramidal arrangements.

  10. Template engineered biopotent macrocyclic complexes involving furan moiety: Molecular modeling and molecular docking

    NASA Astrophysics Data System (ADS)

    Rathi, Parveen; Singh, D. P.

    2015-08-01

    Bioactive cobalt(II), nickel(II), copper(II) and zinc(II) complexes of octaazamacrocycle, 19, 20-dioxa-2,3,5,6,11,12,14,15-octaazatricyclo[14.2.1.1]icosa-1,6,8,10,15,17-hexaene-4,13-dithione, derived from furan-2,5-dione and thiocarbonohydrazide in the mole ratio 2:2:1 have been engineered via template methodology. The synthesized metal complexes have also been structurally characterized in the light of various physicochemical techniques and evaluated for antimicrobial and antioxidant activities. All these studies point toward the formation of divalent macrocyclic complexes possessing distorted octahedral geometry and having significant antimicrobial and antioxidant properties as compared to the starting precursors. Virtual screening of a representative complex was done through docking to the binding site of COX-2 to evaluate the anti-inflammatory activity of the series. Non-electrolytic nature of the complexes has been predicted on the basis of low value of molar conductivity in DMSO. All the complexes were having notable activities against pathogenic microbes as compared to precursors-thiocarbonohydrazide and furan-2,5-dione however, the complex 5, [Ni (C10H8N8O2S2) (NO3)2], shows the best antimicrobial activity.

  11. Spectroscopic and biological studies of new binuclear metal complexes of a tridentate ONS hydrazone ligand derived from 4-amino-6-methyl-3-thioxo-3,4-dihydro-1,2,4-triazin-5(2H)-one and 4,6-diacetylresorcinol

    NASA Astrophysics Data System (ADS)

    Adly, Omima M. I.; Emara, Adel A. A.

    2014-11-01

    The binuclear hydrazone, H2L, ligand derived from 4-amino-6-methyl-3-thioxo-3,4-dihydro-1,2,4-triazin-5(2H)-one and 4,6-diacetylresorcinol, in the molar ratio 2:1, and its copper(II), nickel(II), cobalt(II), zinc(II), cadmium(II), cerium(III), iron(III), oxovanadium(IV) and dioxouranium(VI) complexes have been synthesized. Structures of the ligand and its metal complexes were characterized by elemental analyses, spectral (infrared, electronic, mass, 1H NMR and ESR) data, magnetic susceptibility, molar conductivity measurements and thermal gravimetric analysis (TGA). The ligand acts as dibasic with two ONS tridentate sites. The bonding sites are the azomethine nitrogen, phenolate oxygen and sulfur atoms. The metal complexes exhibit different geometrical arrangements such as square planer, tetrahedral and octahedral. The Coats-Redfern equation was used to calculate the kinetic and thermodynamic parameters for the different thermal decomposition steps of some complexes. The ligand and its metal complexes showed antimicrobial activity towards Gram-positive bacteria (Staphylococcus aureus and Bacillus subtilis), Gram-negative bacteria (Salmonella typhimurium and Escherichia coli), yeast (Candida albicans) and fungus (Aspergillus fumigatus). Structural parameters of the ligand and its metal complexes were theoretically computed on the basis of semiempirical PM3 level, and the results were correlated with their experimental data.

  12. Synthesis, characterization and biocidal activity of some transition metal(II) complexes with isatin salicylaldehyde acyldihydrazones.

    PubMed

    Singh, Vinod P; Singh, Shweta; Singh, Divya P

    2012-06-01

    Cobalt(II), nickel(II), copper(II), zinc(II) and cadmium(II) complexes with two new unsymmetrical ligands, isatin salicylaldehyde oxalic acid dihydrazide (isodh) and isatin salicylaldehyde malonic acid dihydrazide (ismdh) were synthesized and characterized by elemental analyses, electrical conductance, magnetic moments, electronic, NMR, ESR and IR spectral studies. The isodh acts as a dibasic tetra dentate ligand bonding through two >C=N-, a deprotonated phenolate and deprotonated indole enolate groups to the metal. The ismdh ligand shows monobasic tetra dentate behaviour in bonding with metal ion through two >C=N-, indole >C=O and a deprotonated phenolate group. The electronic spectral data suggest 4-coordinate square planar geometry for Co(II), Ni(II) and Cu(II) complexes of isodh, whereas, 6-coordinate octahedral structure for the ismdh complexes. The ESR studies also indicate a square planar and distorted octahedral environment around Cu(II) for isodh and ismdh complexes, respectively. Most of the metal complexes show better antifungal activity than the standard and a significant antibacterial activity against various fungi and bacteria. PMID:21679052

  13. Organophosphorus reagents as extractants-part 3. Synergic effect of triphenyl phosphine oxide and bis(diphenyl phosphinyl) alkanes on extraction of iron(III) from thiocyanate medium with 2,4-pentdione.

    PubMed

    Lobana, T S; Bhatia, P K

    1992-06-01

    The extraction of iron(III) from thiocyanate medium was carried out with a synergic combination of 2,4-pentdione (Hacac) and either triphenyl phosphine oxide (Ph(3) PO) or bis (diphenylphosphinyl) alkanes, Ph(2)P(O)(CH(2))(n).P(O)PH(2) [ligand abbreviation, n: dpeO(2), 2; dpbO(2), 4]. Iron(III) was quantitatively separated from its binary mixture with chromium(III), manganese(III), cobalt(II), nickel(II), zinc(II), cadmium(II), mercury(II), lead(II), magnesium(II) and from steel samples. Copper(II) and silver(I) however, interfered. The percentage extraction was 99.0%. The respective extraction constants, K(HA), K(L) or K(syn), for the extracted species, [Fe(NCS)(acac)(2)(H(2)O)] (HA Hacac), Fe(NCS)(3)L(2) [L b Ph(3)PO, dpeO(2) or dpbO(2)], or Fe(NCS)(acac)(2)L were found to be: K(HA), 1.48 x 10(3), K(L), 1.80 x 10(2) (L Ph(3)PO), 2.02 x 10(2) (L dpeO(2) or dpbO(2)) and K(syn), 1.87 x 10(6) (L Ph(3)PO), 2.56 x 10(6) [L dpeO(2) or dpbO(2)]. PMID:18965433

  14. New 1,2,4-triazole-based azo-azomethine dye. Part III: Synthesis, characterization, thermal property, spectrophotometric and computational studies

    NASA Astrophysics Data System (ADS)

    Erfantalab, Malihe; Khanmohammadi, Hamid

    A new 1,2,4-triazole-based azo-azomethine compound, H2L, has been prepared by condensation reaction of 1-(3-formyl-4-hydroxyphenylazo)-4-ethylbenzene with prepared triazole-based diamine. The structure of H2L was characterized by using FT-IR, UV-Vis and 1H NMR spectroscopic methods as well as elemental analysis. Hard model chemometrics method has been used to determine the formation constants of zinc(II), copper(II), nickel(II) and cobalt(II) complexes of H2L in DMSO by UV-Vis spectrophotometric method. Solvatochromic behavior of the dye has been also investigated in some organic solvents with different polarities. Thermal properties of the prepared dye was examined by thermogravimetric analysis. Results indicated that the framework of the dye was stable up to 245 °C. Furthermore,1H chemical shifts and UV-Vis of H2L were studied by the gauge independent atomic orbital (GIAO), continuous set of gauge transformations (CSGT) and time-dependent density functional theory (TD-DFT) methods respectively at the level of density functional theory using B3LYP/6-311+G(d) basis sets in DMSO. The computational data are in reasonably good agreement with the experimental data.

  15. Synthesis, spectroscopic studies, thermal analyses, biological activity of tridentate coordinated transition metal complexes of bi(pyridyl-2-ylmethyl)amine]ligand

    NASA Astrophysics Data System (ADS)

    Abd El-Halim, Hanan F.; Mohamed, Gehad G.

    2016-01-01

    A new tridentate acyclic pincer ligand, [bi(pyridin-2-methyl)amine] (bpma, HL), was synthesized and reacted to form complexes with copper(II), nickel(II), iron(II), cobalt(II) and zinc(II) ions. Both the ligand and its complexes were characterized using elemental analysis, molar conductance, infrared, 1H-NMR-spectroscopy, mass and thermal analyses. According to the spectroscopic data, all of the complexes share the same coordination environment around the metal atoms, consisting two nitrogen-pyridine entities, one nitrogen-methylamine entity, one/two water molecules and/or one/two chloride or bromide ions. Complexes also showed molar conductivity according to the presence of two halide anions outer the coordination sphere except Co(II) and Zn(II) complexes are non electrolytes. Analysis indicates that the metal ions have trigonal bipyramidal structure. Cu(II), Ni(II), Fe(II), Co(II), and Zn(II) metal complexes were screened for their antibacterial activity against Bacillus subtilis, Staphylococcus aureus (G+) and Escherichia coli, and Pseudomonas aeruginosa (G-) bacteria. They showed remarkable antimicrobial activity.

  16. New 1,2,4-triazole-based azo-azomethine dye. Part III: Synthesis, characterization, thermal property, spectrophotometric and computational studies.

    PubMed

    Erfantalab, Malihe; Khanmohammadi, Hamid

    2014-05-01

    A new 1,2,4-triazole-based azo-azomethine compound, H2L, has been prepared by condensation reaction of 1-(3-formyl-4-hydroxyphenylazo)-4-ethylbenzene with prepared triazole-based diamine. The structure of H2L was characterized by using FT-IR, UV-Vis and (1)H NMR spectroscopic methods as well as elemental analysis. Hard model chemometrics method has been used to determine the formation constants of zinc(II), copper(II), nickel(II) and cobalt(II) complexes of H2L in DMSO by UV-Vis spectrophotometric method. Solvatochromic behavior of the dye has been also investigated in some organic solvents with different polarities. Thermal properties of the prepared dye was examined by thermogravimetric analysis. Results indicated that the framework of the dye was stable up to 245 °C. Furthermore,(1)H chemical shifts and UV-Vis of H2L were studied by the gauge independent atomic orbital (GIAO), continuous set of gauge transformations (CSGT) and time-dependent density functional theory (TD-DFT) methods respectively at the level of density functional theory using B3LYP/6-311+G(d) basis sets in DMSO. The computational data are in reasonably good agreement with the experimental data. PMID:24577255

  17. Modifications of boronic ester pro-chelators triggered by hydrogen peroxide tune reactivity to inhibit metal-promoted oxidative stress.

    PubMed

    Charkoudian, Louise K; Pham, David M; Kwon, Ashley M; Vangeloff, Abbey D; Franz, Katherine J

    2007-11-21

    Several new analogs of salicylaldehyde isonicotinoyl hydrazone (SIH) and salicylaldehyde benzoyl hydrazone (SBH) that contain an aryl boronic ester (BSIH, BSBH) or acid (BASIH) in place of an aryl hydroxide have been synthesized and characterized as masked metal ion chelators. These pro-chelators show negligible interaction with iron(III), although the boronic acid versions exhibit some interaction with copper(II), zinc(II) and nickel(II). Hydrogen peroxide oxidizes the aryl boronate to phenol, thus converting the pro-chelators to tridentate ligands with high affinity metal binding properties. An X-ray crystal structure of a bis-ligated iron(III) complex, [Fe(SBH(m-OMe)(3))(2)]NO(3), confirms the meridonal binding mode of these ligands. Modifications of the aroyl ring of the chelators tune their iron affinity, whereas modifications on the boron-containing ring of the pro-chelators attenuate their reaction rates with hydrogen peroxide. Thus, the methoxy derivative pro-chelator (p-OMe)BASIH reacts with hydrogen peroxide nearly 5 times faster than the chloro derivative (m-Cl)BASIH. Both the rate of pro-chelator to chelator conversion as well as the metal binding affinity of the chelator influence the overall ability of these molecules to inhibit hydroxyl radical formation catalyzed by iron or copper in the presence of hydrogen peroxide and ascorbic acid. This pro-chelator strategy has the potential to improve the efficacy of medicinal chelators for inhibiting metal-promoted oxidative stress. PMID:17992288

  18. Task-specific ionic liquid for solubilizing metal oxides.

    PubMed

    Nockemann, Peter; Thijs, Ben; Pittois, Stijn; Thoen, Jan; Glorieux, Christ; Van Hecke, Kristof; Van Meervelt, Luc; Kirchner, Barbara; Binnemans, Koen

    2006-10-26

    Protonated betaine bis(trifluoromethylsulfonyl)imide is an ionic liquid with the ability to dissolve large quantities of metal oxides. This metal-solubilizing power is selective. Soluble are oxides of the trivalent rare earths, uranium(VI) oxide, zinc(II) oxide, cadmium(II) oxide, mercury(II) oxide, nickel(II) oxide, copper(II) oxide, palladium(II) oxide, lead(II) oxide, manganese(II) oxide, and silver(I) oxide. Insoluble or very poorly soluble are iron(III), manganese(IV), and cobalt oxides, as well as aluminum oxide and silicon dioxide. The metals can be stripped from the ionic liquid by treatment of the ionic liquid with an acidic aqueous solution. After transfer of the metal ions to the aqueous phase, the ionic liquid can be recycled for reuse. Betainium bis(trifluoromethylsulfonyl)imide forms one phase with water at high temperatures, whereas phase separation occurs below 55.5 degrees C (temperature switch behavior). The mixtures of the ionic liquid with water also show a pH-dependent phase behavior: two phases occur at low pH, whereas one phase is present under neutral or alkaline conditions. The structures, the energetics, and the charge distribution of the betaine cation and the bis(trifluoromethylsulfonyl)imide anion, as well as the cation-anion pairs, were studied by density functional theory calculations. PMID:17048916

  19. Preparation, spectral and biological investigation of formaldehyde-based ligand containing piperazine moiety and its various polymer metal complexes

    NASA Astrophysics Data System (ADS)

    Khan, Shamim Ahmad; Nishat, Nahid; Parveen, Shadma; Rasool, Raza

    2011-10-01

    A novel tetradentate salicylic acid-formaldehyde ligand containing piperazine moiety (SFP) was synthesized by condensation of salicylic acid, formaldehyde and piperazine in presence of base catalyst, which was subjected for the preparation of coordination polymers with metal ions like manganese(II), cobalt(II), copper(II), nickel(II) and zinc(II). All the synthesized polymeric compounds were characterized by elemental analysis, IR, 1H NMR and electronic spectral studies. The thermal stability was determined by thermogravimetric analysis and thermal data revealed that all the polymer metal complexes show good thermal stability than their parent ligand. Electronic spectral data and magnetic moment values revealed that polymer metal complexes of Mn(II), Co(II) and Ni(II) show an octahedral geometry while Cu(II) and Zn(II) show distorted octahedral and tetrahedral geometry respectively. The antimicrobial screening of the ligand and coordination polymers was done by using Agar well diffusion method against various bacteria and fungi. It was evident from the data that antibacterial and antifungal activity increased on chelation and all the polymer metal complexes show excellent antimicrobial activity than their parent ligand.

  20. Preparation, spectral and biological investigation of formaldehyde-based ligand containing piperazine moiety and its various polymer metal complexes.

    PubMed

    Khan, Shamim Ahmad; Nishat, Nahid; Parveen, Shadma; Rasool, Raza

    2011-10-15

    A novel tetradentate salicylic acid-formaldehyde ligand containing piperazine moiety (SFP) was synthesized by condensation of salicylic acid, formaldehyde and piperazine in presence of base catalyst, which was subjected for the preparation of coordination polymers with metal ions like manganese(II), cobalt(II), copper(II), nickel(II) and zinc(II). All the synthesized polymeric compounds were characterized by elemental analysis, IR, (1)H NMR and electronic spectral studies. The thermal stability was determined by thermogravimetric analysis and thermal data revealed that all the polymer metal complexes show good thermal stability than their parent ligand. Electronic spectral data and magnetic moment values revealed that polymer metal complexes of Mn(II), Co(II) and Ni(II) show an octahedral geometry while Cu(II) and Zn(II) show distorted octahedral and tetrahedral geometry respectively. The antimicrobial screening of the ligand and coordination polymers was done by using Agar well diffusion method against various bacteria and fungi. It was evident from the data that antibacterial and antifungal activity increased on chelation and all the polymer metal complexes show excellent antimicrobial activity than their parent ligand. PMID:21757398

  1. Spectroscopic and biological studies of new binuclear metal complexes of a tridentate ONS hydrazone ligand derived from 4-amino-6-methyl-3-thioxo-3,4-dihydro-1,2,4-triazin-5(2H)-one and 4,6-diacetylresorcinol.

    PubMed

    Adly, Omima M I; Emara, Adel A A

    2014-11-11

    The binuclear hydrazone, H2L, ligand derived from 4-amino-6-methyl-3-thioxo-3,4-dihydro-1,2,4-triazin-5(2H)-one and 4,6-diacetylresorcinol, in the molar ratio 2:1, and its copper(II), nickel(II), cobalt(II), zinc(II), cadmium(II), cerium(III), iron(III), oxovanadium(IV) and dioxouranium(VI) complexes have been synthesized. Structures of the ligand and its metal complexes were characterized by elemental analyses, spectral (infrared, electronic, mass, 1H NMR and ESR) data, magnetic susceptibility, molar conductivity measurements and thermal gravimetric analysis (TGA). The ligand acts as dibasic with two ONS tridentate sites. The bonding sites are the azomethine nitrogen, phenolate oxygen and sulfur atoms. The metal complexes exhibit different geometrical arrangements such as square planer, tetrahedral and octahedral. The Coats-Redfern equation was used to calculate the kinetic and thermodynamic parameters for the different thermal decomposition steps of some complexes. The ligand and its metal complexes showed antimicrobial activity towards Gram-positive bacteria (Staphylococcus aureus and Bacillus subtilis), Gram-negative bacteria (Salmonella typhimurium and Escherichia coli), yeast (Candida albicans) and fungus (Aspergillus fumigatus). Structural parameters of the ligand and its metal complexes were theoretically computed on the basis of semiempirical PM3 level, and the results were correlated with their experimental data. PMID:24858350

  2. Self-assembled copper(II) coordination polymers derived from aminopolyalcohols and benzenepolycarboxylates: structural and magnetic properties.

    PubMed

    Kirillov, Alexander M; Karabach, Yauhen Y; Haukka, Matti; Guedes da Silva, M Fatima C; Sanchiz, Joaquin; Kopylovich, Maximilian N; Pombeiro, Armando J L

    2008-01-01

    The new copper(II) or copper(II)/sodium(I) 1D coordination polymers [Cu2(Hmdea)2(mu-H2O)(mu2-tpa)]n.2nH2O (1), [Cu2(H2tipa)2(mu2-ipa)]n.4nH2O (2), [Cu2(H2tea)2Na(H2O)2(mu2-tma)]n.6nH2O (3), [Cu2(H2tea)2(mu2-ipa)]n.nH2O (4a), and [Cu2(H2tea)2{mu3-Na(H2O)3}(mu3-ipa)]n(NO3)n.0.5nH2O (4b) have been prepared in aqueous medium by self-assembly from copper(II) nitrate, aminopolyalcohols [methyldiethanolamine (H2mdea), triisopropanolamine (H3tipa), and triethanolamine (H3tea)] as main chelating ligands and benzenepolycarboxylic acids [terephthalic (H2tpa), isophthalic (H2ipa), and trimesic (H3tma) acid] as spacers. They have been characterized by IR spectroscopy, elemental and single-crystal X-ray diffraction analyses, the latter indicating the formation of unusual multinuclear metal cores interconnected by various benzenepolycarboxylate spacers, leading to distinct wavelike, zigzag, or linear 1D polymeric metal-organic chains. These are further extended to 2D or 3D hydrogen-bonded supramolecular networks via extensive interactions with the intercalated crystallization water molecules. The latter are associated, also with aqua ligands, by hydrogen bonds resulting in acyclic (H2O)3 clusters in 1, (H2O)8 clusters in 2, infinite 1D water chains in 3, and disordered water-nitrate associates in 4b, all playing a key role in the structure stabilization and its extension to further dimensions. Variable-temperature magnetic susceptibility measurements have shown that 1-4 exhibit a moderately strong ferromagnetic coupling through the alkoxo bridge. The small Cu-O-Cu bridging angle and the large out-of-plane displacement of the carbon atom of the alkoxo group accounts for this behavior. The magnetic data have been analyzed by means of a dinuclear and a 1D chain model, and the magnetic parameters have been determined. The magnetic exchange coupling in 3, to our knowledge, is the highest found in alkoxo-bridged copper(II) complexes. PMID:18069826

  3. Rapid assessment of human amylin aggregation and its inhibition by copper(II) ions by laser ablation electrospray ionization mass spectrometry with ion mobility separation.

    PubMed

    Li, Hang; Ha, Emmeline; Donaldson, Robert P; Jeremic, Aleksandar M; Vertes, Akos

    2015-10-01

    Native electrospray ionization (ESI) mass spectrometry (MS) is often used to monitor noncovalent complex formation between peptides and ligands. The relatively low throughput of this technique, however, is not compatible with extensive screening. Laser ablation electrospray ionization (LAESI) MS combined with ion mobility separation (IMS) can analyze complex formation and provide conformation information within a matter of seconds. Islet amyloid polypeptide (IAPP) or amylin, a 37-amino acid residue peptide, is produced in pancreatic beta-cells through proteolytic cleavage of its prohormone. Both amylin and its precursor can aggregate and produce toxic oligomers and fibrils leading to cell death in the pancreas that can eventually contribute to the development of type 2 diabetes mellitus. The inhibitory effect of the copper(II) ion on amylin aggregation has been recently discovered, but details of the interaction remain unknown. Finding other more physiologically tolerated approaches requires large scale screening of potential inhibitors. Here, we demonstrate that LAESI-IMS-MS can reveal the binding stoichiometry, copper oxidation state, and the dissociation constant of human amylin-copper(II) complex. The conformations of hIAPP in the presence of copper(II) ions were also analyzed by IMS, and preferential association between the β-hairpin amylin monomer and the metal ion was found. The copper(II) ion exhibited strong association with the -HSSNN- residues of the amylin. In the absence of copper(II), amylin dimers were detected with collision cross sections consistent with monomers of β-hairpin conformation. When copper(II) was present in the solution, no dimers were detected. Thus, the copper(II) ions disrupt the association pathway to the formation of β-sheet rich amylin fibrils. Using LAESI-IMS-MS for the assessment of amylin-copper(II) interactions demonstrates the utility of this technique for the high-throughput screening of potential inhibitors of amylin

  4. Rapid Assessment of Human Amylin Aggregation and Its Inhibition by Copper(II) Ions by Laser Ablation Electrospray Ionization Mass Spectrometry with Ion Mobility Separation

    PubMed Central

    Donaldson, Robert P.; Jeremic, Aleksandar M.; Vertes, Akos

    2015-01-01

    Native electrospray ionization (ESI) mass spectrometry (MS) is often used to monitor noncovalent complex formation between peptides and ligands. The relatively low throughput of this technique, however, is not compatible with extensive screening. Laser ablation electrospray ionization (LAESI) MS combined with ion mobility separation (IMS) can analyze complex formation and provide conformation information within a matter of seconds. Islet amyloid polypeptide (IAPP) or amylin, a 37-amino acid residue peptide, is produced in pancreatic beta-cells through proteolytic cleavage of its prohormone. Both amylin and its precursor can aggregate and produce toxic oligomers and fibrils leading to cell death in the pancreas that can eventually contribute to the development of type 2 diabetes mellitus. The inhibitory effect of the copper(II) ion on amylin aggregation has been recently discovered, but details of the interaction remain unknown. Finding other more physiologically tolerated approaches requires large scale screening of potential inhibitors. Here, we demonstrate that LAESI-IMS-MS can reveal the binding stoichiometry, copper oxidation state, and the dissociation constant of human amylin–copper(II) complex. The conformations of hIAPP in the presence of copper(II) ions were also analyzed by IMS, and preferential association between the β-hairpin amylin monomer and the metal ion was found. The copper(II) ion exhibited strong association with the –HSSNN– residues of the amylin. In the absence of copper(II), amylin dimers were detected with collision cross sections consistent with monomers of β-hairpin conformation. When copper(II) was present in the solution, no dimers were detected. Thus, the copper(II) ions disrupt the association pathway to the formation of β-sheet rich amylin fibrils. Using LAESI-IMS-MS for the assessment of amylin–copper(II) interactions demonstrates the utility of this technique for the high-throughput screening of potential inhibitors of

  5. Nickel(II) Complexation with Nitrate in Dry [C4mim][Tf2N] Ionic Liquid: A Spectroscopic, Microcalorimetric, and Molecular Dynamics Study.

    PubMed

    Melchior, Andrea; Gaillard, Clotilde; Gràcia Lanas, Sara; Tolazzi, Marilena; Billard, Isabelle; Georg, Sylvia; Sarrasin, Lola; Boltoeva, Maria

    2016-04-01

    The complex formation of nitrate ions with nickel(II) in dry [C4mim][Tf2N] ionic liquid (IL) was investigated by means of UV-visible spectrophotometry, isothermal titration calorimetry (ITC), extended X-ray absorption fine structure spectroscopy (EXAFS), and molecular dynamics (MD) simulations. EXAFS spectroscopy and MD simulations show that the solvated Ni(II) cation is initially coordinated by the oxygens of the [Tf2N](-) anion of IL, which can behave either as mono- or bidentate. Spectroscopic and thermodynamic data show that Ni(II) is able to form up to three stable mononuclear complexes with nitrate in this solvent. The stability constants for Ni(NO3)j complexes (j = 1-3) calculated from spectrophotometry and ITC experiments decrease in the order log K1 > log K2 > log K3. The formation of the first two species is enthalpy-driven, while the third species is entropy-stabilized. The UV-vis spectra of solutions containing different nitrate/Ni(II) ratios show that the metal ion retains the six-coordinate geometry. Furthermore, the EXAFS evidences that nitrate is always bidentate. Molecular dynamics simulations show that the [Tf2N](-) anions bind Ni(II) through the sulfonyl oxygen atoms and can coordinate either as monodentate or chelate. The analysis of the MD data shows that introduction of nitrates in the first coordination sphere of the metal ion results in remarkable structural rearrangement of the ionic liquid. PMID:26999457

  6. Synthesis, crystal structure, fluorescence and electrochemical studies of a new tridentate Schiff base ligand and its nickel(II) and palladium(II) complexes

    NASA Astrophysics Data System (ADS)

    Shafaatian, Bita; Soleymanpour, Ahmad; Kholghi Oskouei, Nasim; Notash, Behrouz; Rezvani, Seyyed Ahmad

    2014-07-01

    A new unsymmetrical tridentate Schiff base ligand was derived from the 1:1 M condensation of ortho-vanillin with 2-mercaptoethylamine. Nickel and palladium complexes were obtained by the reaction of the tridentate Schiff base ligand with nickel(II) acetate tetrahydrate and palladium(II) acetate in 2:1 M ratio. In nickel and palladium complexes the ligand was coordinated to metals via the imine N and enolic O atoms. The S groups of Schiff bases were not coordinated to the metals and S-S coupling was occured. The complexes have been found to possess 1:2 Metal:Ligand stoichiometry and the molar conductance data revealed that the metal complexes were non-electrolytes. The complexes exhibited octahedral coordination geometry. The emission spectra of the ligand and its complexes were studied in methanol. Electrochemical properties of the ligand and its metal complexes were investigated in the CH3CN solvent at the 100 mV s-1 scan rate. The ligand and metal complexes showed both reversible and quasi-reversible processes at this scan rate. The Schiff base and its complexes have been characterized by IR, 1H NMR, UV/Vis, elemental analyses and conductometry. The crystal structure of nickel complex has been determined by single crystal X-ray diffraction.

  7. DNA binding, antioxidant, cytotoxicity (MTT, lactate dehydrogenase, NO), and cellular uptake studies of structurally different nickel(II) thiosemicarbazone complexes: synthesis, spectroscopy, electrochemistry, and X-ray crystallography.

    PubMed

    Prabhakaran, R; Kalaivani, P; Huang, R; Poornima, P; Vijaya Padma, V; Dallemer, F; Natarajan, K

    2013-02-01

    Three new nickel(II) thiosemicarbazone complexes have been synthesized and characterized by analytical, spectral, and single-crystal X-ray diffraction studies. In complex 1, the ligand 2-hydroxy-1-naphthaldehydethiosemicarbazone coordinated as a monobasic tridentate donor, whereas in complexes 2 and 3, the ligands salicylaldehyde-4(N)-ethylthiosemicarbazone and 2-hydroxy-1-naphthaldehyde-4(N)-ethylthiosemicarbazone coordinated as a dibasic tridentate donor. The DNA binding ability of the complexes in calf thymus DNA was explored by absorption and emission titration experiments. The antioxidant property of the new complexes was evaluated to test their free-radical scavenging ability. In vitro cytotoxicity assays were performed for the new complexes in A549 and HepG2 cell lines. The new compounds overcome cisplatin resistance in the A549 cell line and they were also active in the HepG2 cell line. The cellular uptake study showed the accumulation of the complexes in tumor cells depended on the nature of the ligand attached to the nickel ion. PMID:23274397

  8. Synthesis, characterization, single crystal X-ray determination, fluorescence and electrochemical studies of new dinuclear nickel(II) and oxovanadium(IV) complexes containing double Schiff base ligands.

    PubMed

    Shafaatian, Bita; Ozbakzaei, Zahra; Notash, Behrouz; Rezvani, S Ahmad

    2015-04-01

    A series of new bimetallic complexes of nickel(II) and vanadium(IV) have been synthesized by the reaction of the new double bidentate Schiff base ligands with nickel acetate and vanadyl acetylacetonate in 1:1 M ratio. In nickel and also vanadyl complexes the ligands were coordinated to the metals via the imine N and enolic O atoms. The complexes have been found to possess 1:1 metals to ligands stoichiometry and the molar conductance data revealed that the metal complexes were non-electrolytes. The nickel and vanadyl complexes exhibited distorted square planar and square pyramidal coordination geometries, respectively. The emission spectra of the ligands and their complexes were studied in methanol. Electrochemical properties of the ligands and their metal complexes were also investigated in DMSO solvent at 150 mV s(-1) scan rate. The ligands and metal complexes showed both quasi-reversible and irreversible processes at this scan rate. The Schiff bases and their complexes have been characterized by FT-IR, 1H NMR, UV/Vis spectroscopies, elemental analysis and conductometry. The crystal structure of the nickel complex has been determined by single crystal X-ray diffraction. PMID:25613693

  9. Mechanism of Action of the Novel Nickel(II) Complex in Simultaneous Reactivation of the Apoptotic Signaling Networks Against Human Colon Cancer Cells

    PubMed Central

    Samie, Nima; Haerian, Batoul Sadat; Muniandy, Sekaran; Marlina, Anita; Kanthimathi, M. S.; Abdullah, Norbani B.; Ahmadian, Gholamreza; Aziddin, Raja E. R.

    2016-01-01

    The aim of this study was to evaluate the cytotoxic potential of a novel nickel(II) complex (NTC) against WiDr and HT-29 human colon cancer cells by determining the IC50 using the standard MTT assay. The NTC displayed a strong suppressive effect on colon cancer cells with an IC50 value of 6.07 ± 0.22 μM and 6.26 ± 0.13 μM against WiDr and HT-29 respectively, after 24 h of treatment. Substantial reduction in the mitochondrial membrane potential and increase in the release of cytochrome c from the mitochondria directed the induction of the intrinsic apoptosis pathway by the NTC. Activation of this pathway was further evidenced by significant activation of caspase 3/7 and 9. The NTC was also shown to activate the extrinsic pathway of apoptosis via activation of caspase-8 which is linked to the suppression of NF-κB translocation to the nucleus. Cell cycle arrest in the G1 phase was confirmed by flow cytometry and up-regulation of glutathione reductase expression was quantified by qPCR. Results of the current work indicates that NTC possess a potent cancer cell abolishing activity by simultaneous induction of intrinsic and extrinsic pathways of apoptosis in colon cancer cell lines. PMID:26858642

  10. Synthesis, X-ray, and Spectroscopic Study of Dissymmetric Tetrahedral Zinc(II) Complexes from Chiral Schiff Base Naphthaldiminate Ligands with Apparent Exception to the ECD Exciton Chirality.

    PubMed

    Enamullah, Mohammed; Makhloufi, Gamall; Ahmed, Rifat; Joy, Baitul Alif; Islam, Mohammad Ariful; Padula, Daniele; Hunter, Howard; Pescitelli, Gennaro; Janiak, Christoph

    2016-07-01

    Bidentate enantiopure Schiff base ligands, (R or S)-N-1-(Ar)ethyl-2-oxo-1-naphthaldiminate (R- or S-N^O), diastereoselectively provide Λ- or Δ-chiral-at-metal four-coordinated Zn(R- or S-N^O)2 {Ar = C6H5; Zn-1R or Zn-1S and p-C6H4OMe; Zn-2R or Zn-2S}. Two R- or S-N^O-chelate ligands coordinate to the zinc(II) in a tetrahedral mode and induce Λ- or Δ-configuration at the zinc metal center. In the solid state, the R- or S-ligand diastereoselectively gives Λ- or Δ-Zn configuration, respectively, and forms enantiopure crystals. Single crystal structure determinations show two symmetry-independent molecules (A and B) in each asymmetric unit to give Z' = 2 structures. Electronic circular dichroism (ECD) spectra show the expected mirror image relationship resulting from diastereomeric excess toward the Λ-Zn for R-ligands and Δ-Zn for S-ligands in solution. ECD spectra are well reproduced by TDDFT calculations, while the application of the exciton chirality method, in the common point-dipole approximation, predicts the wrong sign for the long-wavelength couplet. A dynamic diastereomeric equilibrium (Λ vs Δ) prevails for both R- and S-ligand-metal complexes in solution, respectively, evidenced by (1)H NMR spectroscopy. Variable temperature (1)H NMR spectra show a temperature-dependent shift of the diastereomeric equilibrium and confirm Δ-Zn configuration (for S-ligand) to be the most stable one and favored at low temperature. DSC analyses provide quantitative diastereomeric excess in the solid state for Zn-2R and Zn-2S, which is comparable to the results of solution studies. PMID:27295327

  11. A zinc(II) quinolinone complex (Et3NH)[Zn(qui)Cl2]: Synthesis, X-ray structure, spectral properties and in vitro cytotoxicity

    NASA Astrophysics Data System (ADS)

    Buchtík, Roman; Nemec, Ivan; Trávníček, Zdeněk

    2014-02-01

    A new zinc(II) complex with 2-phenyl-3-hydroxy-4(1H)-quinolinone (Hqui) of the composition (Et3NH)[Zn(qui)Cl2] was prepared and characterized by elemental analysis, FT IR, 1D and 2D NMR, and fluorescence spectroscopy, mass spectrometry and single crystal X-ray analysis. The molecular structure is composed of the triethylammonium (Et3NH+) cations and tetrahedral [ZnII(qui)Cl2]- complex anions, in which the Zn(II) atoms are bidentate coordinated by one qui ligand through keto (OK) and phenolate (OP) oxygen atoms and by two chlorido ligands, thus forming the {O2Cl2} donor set, with Zn-OK = 1.9860(14) Å, Zn-OP 1.9961(14) Å and Zn-Cl = 2.2509(6) Å and 2.2266(6) Å. The complex cations are aligned into 1D supramolecular chains through the NH⋯Cl hydrogen bonding between the amine group of the quinolinone ligand and the chlorido ligand of the adjacent complex anion. The amine group from the Et3NH+ cations provides the NH⋯OP hydrogen bond with the phenolate oxygen atoms from the complex anion. Screening of in vitro cytotoxicity of the compound was studied on human osteosarcoma (HOS) and human breast adenocarcinoma (MCF7) cell lines, with IC50 > 50 μM. The fluorescence study showed that the complex exhibits a relatively high integral intensity (29%) as compared to the standard quinine sulfate, and 1.6-fold enhancement of emission with respect to free Hqui.

  12. Selective extraction of zinc(II) over iron(II) from spent hydrochloric acid pickling effluents by liquid-liquid extraction.

    PubMed

    Mansur, Marcelo Borges; Rocha, Sônia Denise Ferreira; Magalhães, Fernando Silva; Benedetto, Jeaneth dos Santos

    2008-02-11

    The selective removal of zinc(II) over iron(II) by liquid-liquid extraction from spent hydrochloric acid pickling effluents produced by the zinc hot-dip galvanizing industry was studied at room temperature. Two distinct effluents were investigated: effluent 1 containing 70.2g/L of Zn, 92.2g/L of Fe and pH 0.6, and effluent 2 containing 33.9 g/L of Zn, 203.9g/L of Fe and 2M HCl. The following extractants were compared: TBP (tri-n-butyl phosphate), Cyanex 272 [bis(2,4,4-trimethylpentyl)phosphinic acid], Cyanex 301 [bis(2,4,4-trimethylpentyl) dithiophosphinic acid] and Cyanex 302 [bis(2,4,4-trimethylpentyl) monothiophosphinic acid]. The best separation results were obtained for extractants TBP and Cyanex 301. Around 92.5% of zinc and 11.2% of iron were extracted from effluent 1 in one single contact using 100% (v/v) of TBP. With Cyanex 301, around 80-95% of zinc and less than 10% of iron were extracted from effluent 2 at pH 0.3-1.0. For Cyanex 272, the highest extraction yield for zinc (70% of zinc with 20% of iron extraction) was found at pH 2.4. Cyanex 302 presented low metal extraction levels (below 10%) and slow phase disengagement characteristics. Reactions for the extraction of zinc with TBP and Cyanex 301 from hydrochloric acid solution were proposed. PMID:17570579

  13. Effect of temperature on the optical and structural properties of hexadecylamine capped ZnS nanoparticles using Zinc(II) N-ethyl-N-phenyldithiocarbamate as single source precursor

    SciTech Connect

    Onwudiwe, Damian C.; Strydom, Christien; Oluwafemi, Oluwatobi S.; Songca, Sandile P.

    2012-12-15

    Graphical abstract: Display Omitted Highlights: ► HDA-capped ZnS nanoparticles were synthesized via thermolysis of a single source precursor. ► Zinc(II) N-ethyl-N-phenyldithiocarbamate was used as the single source precursor. ► The growth temperature was varied to study the optical properties of the nanocrystals. ► Change in growth temperature affects the structural properties of the ZnS nanoparticles. ► Hexagonal wurtzite phase was obtained at lower temperatures while cubic sphalerite phase was obtained at higher growth temperatures. -- Abstract: Reported in this work is the synthesis of HDA (hexadecylamine)-capped ZnS nanoparticles by a single source route using Zinc(II) N-ethyl-N-phenyldithiocarbamate as a precursor. By varying the growth temperature, the temporal evolution of the optical properties and morphology of the nanocrystals were investigated. The as-synthesized nanoparticles were characterized using UV–vis absorption and photoluminescence (PL) spectroscopy, transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM) and X-ray diffraction (XRD). All the particles exhibited quantum confinement in their optical properties with band edge emission at the early stage of the reaction. The XRD showed transition from hexagonal wurtzite phase to cubic sphalerite phase as the growth temperature increases. The TEM image showed that the particles are small and spherical in shape while the HRTEM image confirmed the crystalline nature of the material.

  14. A new approach for crystallization of copper(II) oxide hollow nanostructures with superior catalytic and magnetic response.

    PubMed

    Singh, Inderjeet; Landfester, Katharina; Chandra, Amreesh; Muñoz-Espí, Rafael

    2015-12-01

    We report the synthesis of copper(II) oxide hollow nanostructures at ambient pressure and close to room temperature by applying the soft templating effect provided by the confinement of droplets in miniemulsion systems. Particle growth can be explained by considering a mechanism that involves both diffusion and reaction control. The catalytic reduction of p-nitrophenol in aqueous media is used as a model reaction to prove the catalytic activity of the materials: the synthesized hollow structures show nearly 100 times higher rate constants than solid CuO microspheres. The kinetic behavior and the order of the reduction reaction change due to the increase of the surface area of the hollow structures. The synthesis also leads to modification of physical properties such as magnetism. PMID:26525922

  15. Extraction of copper(II) from acid chloride solutions by N-dodecyl- and N,N-dihexylpyridinecarboxamides

    SciTech Connect

    Borowiak-Resterna, A.

    1999-01-01

    N-dodecyl- and N,N-dihexylpyridinecarboxamides with amide group at 2, 3 or 4 position were synthesized. Model individual amides were used to recover copper(II) from chloride solutions at constant water activity and constant total concentration of dissolved species in aqueous solution. It was found, that pyridine-2-carboxamide forms with copper complexes (CuCl{sub 2}){sub x}(Ext){sub 2}. Remaining amides form with copper complexes CuCl{sub 2}(Ext){sub 2}. Monoalkylamides are not suitable for extraction because they and their complexes are slightly soluble in the hydrocarbon diluents. N,N-dialkylpyridinecarboxamides and their copper complexes are sufficiently soluble in the hydrocarbon phase to carry out extraction. However, they are strong extractants and extract efficiently copper already from dilute chloride solutions ([Cl{sup {minus}}] = 0.1 M). They extract also significant amounts of copper from concentrated (3--4 M) nitrate solutions.

  16. A fluorescence turn-on detection of copper(II) based on the template-dependent click ligation of oligonucleotides.

    PubMed

    Wang, Fangyuan; Li, Yongxin; Li, Wenying; Chen, Jian; Zhang, Qingfeng; Anjum Shahzad, Sohail; Yu, Cong

    2015-01-01

    In this work, a fluorescence turn-on method for copper(II) detection is reported. A molecular beacon (MB) was designed as a template. Cu(2+) was reduced to Cu(+) in the presence of a reductant (ascorbic acid). Two short single-stranded oligonucleotides one was labeled with a 5'-alkyne and the other with 3'-azide group, proceeded a template-dependent chemical ligation through the Cu(I)-catalyzed azide-alkyne cycloaddition. The newly generated click-ligated long chain oligonucleotide, which was complementary to the MB, opened the MB hairpin structure and resulted in a turn on fluorescence. The increase in fluorescence intensity is directly proportional to the amount of Cu(2+) added to the assay solution. The present assay is quite sensitive and allows the detection of 2 nM Cu(2+). The described assay also exhibits high selectivity over other metal ions. PMID:25476281

  17. Studies on interaction between gatifloxacin and human serum albumin as well as effect of copper(II) on the reaction

    NASA Astrophysics Data System (ADS)

    Tan, Fei; Guo, Ming; Yu, QinSen

    2005-10-01

    The binding characteristics of gatifloxacin (GTFX) and human serum albumin (HSA) have been studied by fluorescence spectroscopy in aqueous solution, and the interaction influenced by copper(II) was also explored in the paper. The results show that the two-reaction equilibrium constant and the number of binding sites were K = 1.16 × 10 5 l mol -1, n = 1.27 for GTFX and K = 1.62 × 10 5 l mol -1, n = 1.74 for GTFX-Cu 2+, respectively. The quenching mechanism of fluorescence of HSA by GTFX is a static quenching procedure. The binding distance between GTFX and HSA and the energy transfer efficiency are obtained based on the theory of Fōrster spectroscopy energy transfer. The effect of GTFX on the conformation of HSA was also been analyzed by using synchronous fluorescence spectroscopy. The interaction of GTFX and HSA has been studied by flow-mixed microcalorimetry in the absence and presence of copper(II) and their thermodynamic parameters were obtained. The enthalpy changes and the entropy changes were calculated to be Δ H ≈ 0, Δ S > 0 in the absence of copper(II),which indicated that static forces played major role in the interaction of GTFX and HSA, and to be Δ H ≈ 0, Δ S > 0 in the presence of copper(II),which indicated that the static forces also played major role on the reaction. The molar free energy changes of the two reactions are identical with each other because the entropy-enthalpy compensation happened between the two reactions.

  18. Ferrocenyl-L-amino acid copper(II) complexes showing remarkable photo-induced anticancer activity in visible light.

    PubMed

    Goswami, Tridib K; Gadadhar, Sudarshan; Balaji, Babu; Gole, Bappaditya; Karande, Anjali A; Chakravarty, Akhil R

    2014-08-21

    Ferrocene-conjugated copper(ii) complexes [Cu(Fc-aa)(aip)](ClO4) () and [Cu(Fc-aa)(pyip)](ClO4) () of l-amino acid reduced Schiff bases (Fc-aa), 2-(9-anthryl)-1H-imidazo[4,5-f][1,10]phenanthroline (aip) and 2-(1-pyrenyl)-1H-imidazo[4,5-f][1,10]phenanthroline (pyip), where Fc-aa is ferrocenylmethyl-l-tyrosine (Fc-Tyr in , ), ferrocenylmethyl-l-tryptophan (Fc-Trp in , ) and ferrocenylmethyl-l-methionine (Fc-Met in , ), were prepared and characterized, and their photocytotoxicity was studied (Fc = ferrocenyl moiety). Phenyl analogues, viz. [Cu(Ph-Met)(aip)](ClO4) () and [Cu(Ph-Met)(pyip)](ClO4) (), were prepared and used as control compounds. The bis-imidazophenanthroline copper(ii) complexes, viz. [Cu(aip)2(NO3)](NO3) () and [Cu(pyip)2(NO3)](NO3) (), were also prepared and used as controls. Complexes having a redox inactive cooper(ii) center showed the Fc(+)-Fc redox couple at ∼0.5 V vs. SCE in DMF-0.1 mol [Bu(n)4N](ClO4). The copper(ii)-based d-d band was observed near 600 nm in DMF-Tris-HCl buffer (1 : 1 v/v). The ferrocenyl complexes showed low dark toxicity, but remarkably high photocytotoxicity in human cervical HeLa and human breast adenocarcinoma MCF-7 cancer cells giving an excellent photo-dynamic effect while their phenyl analogues were inactive. The photo-exposure caused significant morphological changes in the cancer cells when compared to the non-irradiated ones. The photophysical processes were rationalized from the theoretical studies. Fluorescence microscopic images showed and localizing predominantly in the endoplasmic reticulum (ER) of the cancer cells, thus minimizing any undesirable effects involving nuclear DNA. PMID:24971754

  19. Comparison of availability of copper(II) complexes with organic ligands to bacterial cells and to chitin

    SciTech Connect

    Vasconcelos, M.T.S.D.; Azenha, M.A.O.; Cabral, J.P.S.

    1997-10-01

    Bacterial cells or chitin were exposed to solutions with 100 {micro}M total but only 5 {micro}M free copper, due to the presence of a proper concentration of proline, lysine, cysteine, or ethylenediamine tetraacetate (EDTA). The influence of the nature and concentration of the particles and soluble ligands, on the sorption and on the desorption of the copper, at pH 6.50 and 25.0 C, was investigated. The metal sorbed by the particles and that left in the solution were measured by atomic absorption spectrometry, after different periods of contact between particles and solution. The interpretation of the results was based on the copper(II) speciation calculated through equilibrium approaches applied to homogeneous or heterogeneous systems. A significant fraction of copper bound to the organic ligands was displaced to the bacteria or chitin, and the extent of chemical reaction depended on the nature of both the soluble (or leaving) ligands and sites on the particle surface (or entering ligands), as expected by the equilibrium theory. But with chitin, the uptake of copper in the presence of cysteine or EDTA was higher than expected, which may be due to the adsorption of the soluble copper complexes on the particle surface. In consequence of a competition between soluble and particulate ligands (cells or chitin), the free copper(II) concentration decreased in the solution, even in the presence of very strong chelators. The results indicate that copper availability is not a simple function of the initial free copper concentration in the solution. Desorption of the previously fixed copper, originated by free soluble ligands indicated that the sorption of copper was quasireversible for both particles, though a larger dismissal of the equilibrium position occurred for the cells, probably due to their biological activity.

  20. Mixed-ligand copper(II) phenolate complexes: Synthesis, spectral characterization, phosphate-hydrolysis, antioxidant, DNA interaction and cytotoxic studies

    NASA Astrophysics Data System (ADS)

    Gurumoorthy, Perumal; Mahendiran, Dharmasivam; Prabhu, Durai; Arulvasu, Chinnasamy; Rahiman, Aziz Kalilur

    2015-01-01

    A series of phenol-based mixed-ligand copper(II) complexes of the type [CuL1-4(diimine)] (1-8), where L1-4 = N1,N2-bis(5-substituted-2-hydroxybenzylidene)-1,2-ethylene/phenylenediimine and diimine = 2,2‧-bipyridyl (bpy) or 1,10-phenanthroline (phen), have been isolated and fully characterized by analytical and spectral techniques. Electronic spectra of complexes suggest Cu(II) cation has a d9 electronic configuration, adopting distorted octahedral geometry with axial elongation, due to Jahn-Teller effect. Electrochemical studies of complexes evidenced one-electron irreversible reduction wave in the cathodic region. The observed rate constant (k) values for the hydrolysis of 4-nitrophenylphosphate (4-NPP) are in the range of 0.25-3.82 × 10-2 min-1. The obtained room temperature magnetic moment values (1.79-1.90 BM) lies within the range observed for octahedral copper(II) complexes. Antioxidant studies revealed that these complexes possess considerable radical scavenging potency against DPPH. The binding studies of complexes with calf thymus DNA (CT-DNA) revealed intercalation with minor-groove binding, and the complex 4 exhibits highest binding activity than the other complexes. The cleavage activity on supercoiled pBR322 DNA revealed the involvement of hydroxyl radical and singlet-oxygen as reactive oxygen species, and complexes encourage binding to minor-groove. Further, the cytotoxicity of complex 4 on human hepatocellular liver carcinoma HepG2 cell line implies the cell death through apoptosis.

  1. A new approach for crystallization of copper(ii) oxide hollow nanostructures with superior catalytic and magnetic response

    NASA Astrophysics Data System (ADS)

    Singh, Inderjeet; Landfester, Katharina; Chandra, Amreesh; Muñoz-Espí, Rafael

    2015-11-01

    We report the synthesis of copper(ii) oxide hollow nanostructures at ambient pressure and close to room temperature by applying the soft templating effect provided by the confinement of droplets in miniemulsion systems. Particle growth can be explained by considering a mechanism that involves both diffusion and reaction control. The catalytic reduction of p-nitrophenol in aqueous media is used as a model reaction to prove the catalytic activity of the materials: the synthesized hollow structures show nearly 100 times higher rate constants than solid CuO microspheres. The kinetic behavior and the order of the reduction reaction change due to the increase of the surface area of the hollow structures. The synthesis also leads to modification of physical properties such as magnetism.We report the synthesis of copper(ii) oxide hollow nanostructures at ambient pressure and close to room temperature by applying the soft templating effect provided by the confinement of droplets in miniemulsion systems. Particle growth can be explained by considering a mechanism that involves both diffusion and reaction control. The catalytic reduction of p-nitrophenol in aqueous media is used as a model reaction to prove the catalytic activity of the materials: the synthesized hollow structures show nearly 100 times higher rate constants than solid CuO microspheres. The kinetic behavior and the order of the reduction reaction change due to the increase of the surface area of the hollow structures. The synthesis also leads to modification of physical properties such as magnetism. Electronic supplementary information (ESI) available: Associated structural and morphological analysis, XPS characterization, BET surface area, catalytic measurements, recycle tests of the catalyst, and magnetic characterizations. See DOI: 10.1039/c5nr05579b

  2. Conjugation of a new series of dithiocarbazate Schiff base Copper(II) complexes with vectors selected to enhance antibacterial activity.

    PubMed

    Low, May Lee; Maigre, Laure; Dorlet, Pierre; Guillot, Régis; Pagès, Jean-Marie; Crouse, Karen A; Policar, Clotilde; Delsuc, Nicolas

    2014-12-17

    A new series of six Schiff bases derived from S-methyldithiocarbazate (SMDTC) and S-benzyldithiocarbazate (SBDTC) with methyl levulinate (SMML, SBML), levulinic acid (SMLA, SBLA), and 4-carboxybenzaldehyde (SM4CB, SB4CB) were reacted with copper(II), producing complexes of general formula ML2 (M = Cu(II), L = ligand). All compounds were characterized using established physicochemical and spectroscopic methods. Crystal structures were determined for three Schiff bases (SMML, SBML, SBLA) and two Cu(II) complexes (Cu(SMML)2 and Cu(SMLA)2). In order to provide more insight into the behavior of the complexes in solution, electron paramagnetic resonance (EPR) and electrochemical experiments were performed. The parent ligands and their respective copper(II) complexes exhibited moderate antibacterial activity against both Gram-negative and Gram-positive bacteria. The most active ligand (SB4CB) and its analogous S-methyl derivative (SM4CB) were conjugated with various vector moieties: polyarginines (R1, R4, R9, and RW9), oligoethylene glycol (OEG), and an efflux pump blocker, phenylalanine-arginine-β-naphthylamide (PAβN). Nonaarginine (R9) derivatives showed the most encouraging synergistic effects upon conjugation and complexation with copper ion including enhanced water solubility, bacteria cell membrane permeability, and bioactivity. These Cu(II)-R9 derivatives display remarkable antibacterial activity against a wide spectrum of bacteria and, in particular, are highly efficacious against Staphylococcus aureus with minimum inhibitory concentration (MIC) values of 0.5-1 μM. This pioneer study clearly indicates that the conjugation of cell-penetrating peptides (CPPs) to dithiocarbazate compounds greatly enhances their therapeutic potential. PMID:25382115

  3. Chemical speciation and bioavailability of Cu(II). Study of the ionic copper(II) and bis(glycinate)-copper(II) accumulation by Lemna species

    SciTech Connect

    Benda, F.; Kouba, J. )

    1991-03-01

    In this paper, the authors examined the accumulation of copper(II) in, and its toxic effect on, duckweed, a plant which exhibits extremely high concentration factors. The effect of copper(II) was investigated by adding it to the minimal medium in two forms: CuSO{sub 4} and (Cu(Gly){sub 2}). The neutral (2:1) tetracoordinated bis(glycinate)-copper(II) complex is constituted by two five-membered rings bonded to the central copper atom with the cis configuration. This complex was chosen to model the function of a neutral species (eliminating the charge effect) involving a nontoxic ligand, for which - in contrast to the hydrated Cu{sup 2+} species - direct permeation through the cell wall is conceivable.

  4. Synthesis, Spectral, and Biological Properties of Copper(II) Complexes of Thiosemicarbazones of Schiff Bases Derived from 4-Aminoantipyrine and Aromatic Aldehydes

    PubMed Central

    Agarwal, Ram K.; Singh, Lakshman; Sharma, Deepak Kumar

    2006-01-01

    We have synthesized a novel series of Schiff bases by condensation of 4-aminoantipyrine and various aromatic aldehydes followed by reaction with thiosemicarbazide. These thiosemicarbazones are potential ligands toward transition metal ions. The reaction of copper(II) salts with 4[N-(benzalidene)amino]antipyrinethiosemicarbazone (BAAPTS), 4[N-(4′-methoxybenzalidene) amino] antipyrinethiosemicarbozone (MBAAPTS), 4[N-(4′-dimethylamino benzalidene) amino] antipyrinethiosemicarbazone (DABAAPTS), and 4[N-(cinnamalidene) amino] antipyrinethiosemicarbazone (CAAPTS) resulted in the formation of solid complexes with the general composition CuX2 · (H2O)(L)(X = Cl, Br,NO3,NCS, or CH3COO; L = BAAPTS, MBAAPTS, DABAAPTS, or CAAPTS). These complexes were characterized through elemental analysis, molecular weight, electrical conductance, infrared, electronic spectra, and magnetic susceptibilities at room temperature. Copper(II) complexes with BAAPTS and MBAAPTS were screened for antibacterial and antifungal properties and have exhibited potential activity. Thermal stabilities of two representative complexes were also investigated. PMID:17497009

  5. Spectral studies and structure of a 2-hydroxyacetophenone 3-hexamethyleneiminyl thiosemicarbazonate(-2) copper(II) complex containing 1,10-phenanthroline

    NASA Astrophysics Data System (ADS)

    John, Rohith P.; Sreekanth, A.; Prathapachandra Kurup, Maliyeckal R.; Usman, Anwar; Ibrahim, Abdul Razak; Fun, Hoong-Kun

    2003-04-01

    The spectral studies and structure of a ternary complex of copper(II) with 2-hydroxyacetophenone 3-hexamethyliminylthiosemicarbazonate (L 2-) and 1,10-phenanthroline (phen) are reported. The thiosemicarbazone binds to the metal as a dianionic ONS-donor (L 2-) ligand, and forms a complex of the stoichiometry [CuLphen]. The copper(II) complex was characterized by IR and UV/Vis spectroscopies, as well as by solid state room-temperature magnetic susceptibility. Spin Hamiltonian and bonding parameters of the compound are calculated from the EPR spectra. Computer simulation of EPR spectrum in DMF at 77 K aided the calculation of magnetic and bonding parameters of the compound. The structure of the compound is solved by single crystal X-ray diffraction. The geometry around copper is distorted square pyramidal.

  6. Copper(II) tetrafluoroborate complexes with the N(3),N(4)-bridging coordination of 1-(tert-butyl)-1H-tetrazole: synthesis, crystal structure and magnetic properties.

    PubMed

    Degtyarik, Mikhail M; Lyakhov, Alexander S; Ivashkevich, Ludmila S; Matulis, Vitaly E; Matulis, Vadim E; Gruschinski, Sina; Voitekhovich, Sergei V; Kersting, Berthold; Ivashkevich, Oleg A

    2015-11-14

    1-(tert-Butyl)-1H-tetrazole (L) reacts with copper(ii) tetrafluoroborate hexahydrate to give the complexes [Cu2L8(H2O)2](BF4)4 (1) or [Cu3L6(H2O)6](BF4)6 (2) depending on the reaction conditions. These complexes, as well as compound L, were characterized using single crystal X-ray analysis. Complex 1 was found to comprise a dinuclear complex cation [Cu2L8(H2O)2](4+) (the Ci symmetry point group), with six tetrazole ligands L showing monodentate N(4)-coordination, and two ligands L providing two tetrazole ring N(3),N(4) bridges between the copper(ii) cations; water molecules complete the distorted octahedral coordination of the metal ions. Complex 2 includes a linear trinuclear complex cation [Cu3L6(H2O)6](6+) (the S6 symmetry point group), in which neighbouring copper(ii) cations are linked by three ligands L via tetrazole ring N(3),N(4) bridges; central and terminal metal ions show octahedral CuN6 and CuN3O3 coordination cores, respectively. The temperature-dependent magnetic susceptibility measurements of complex 2 revealed that the copper(ii) ions were weakly ferromagnetically coupled showing a coupling constant J of 2.2 cm(-1) {H = -2J(S1S2 + S2S3)}. The quantum-chemical investigation of the electronic structure and basicity of ligand L was carried out. PMID:26442910

  7. Ternary complexes of copper(II) and cobalt(II) involving nitrite/pyrazole and tetradentate N4-coordinate ligand: Synthesis, characterization, structures and antimicrobial activity

    NASA Astrophysics Data System (ADS)

    Solanki, Ankita; Sadhu, Mehul H.; Kumar, Sujit Baran

    2015-12-01

    Five new mononuclear mixed ligand complexes of the type [Cu(NCCH3)(dbdmp)](ClO4)2, [M(ONO)(dbdmp)]ClO4, [M(pz) (dbdmp)](ClO4)2 where M = Cu(II) and Co(II), pz = 3,5-dimethylpyrazole and dbdmp = N,N-diethyl-N‧,N‧-bis((3,5-dimethyl-1H-pyrazol-1-yl)methyl)ethane-1,2-diamine have been synthesized and characterized by physico-chemical and spectroscopy studies. The crystal structures of three copper(II) complexes [Cu(NCCH3)(dbdmp)](ClO4)2, [Cu(ONO)(dbdmp)]ClO4 and [Cu(pz)(dbdmp)](ClO4)2 have been determined by single crystal X-ray diffraction studies. Structural analyses reveal the geometry of [Cu(pz)(dbdmp)](ClO4)2 is distorted square pyramidal and other two copper(II) complexes have distorted trigonal bipyramidal geometry. Molecular composition of cobalt(II) complexes have been determined by mass spectral data. The EPR spectra of copper(II) complexes in frozen acetonitrile solution exhibit axial spectra, characteristic of dx2-y2 ground state. Electrochemical studies of copper(II) complexes using glassy carbon as working electrode in acetonitrile solution show Cu(II)/Cu(I) couple with quasi reversible electron transfer versus Ag/Ag+ reference electrode. Antimicrobial activity of all the synthesized complexes were investigated against two Gram positive and two Gram negative bacterial strains.

  8. Structural diversity of copper(II) complexes with N-(2-pyridyl)imidazolidin-2-ones(thiones) and their in vitro antitumor activity.

    PubMed

    Balewski, Łukasz; Sączewski, Franciszek; Bednarski, Patrick J; Gdaniec, Maria; Borys, Ewa; Makowska, Anna

    2014-01-01

    Six series of structurally different mono- and binuclear copper(II) complexes 5-10 were obtained by reacting N-(2-pyridyl)imidazolidin-2-ones (1a-l), N,N'-bis(2-pyridyl)imidazolidin-2-ones (2a,b), N-acyl-N'(2-pyridyl)imidazolodin-2-ones (3a-j) and N-(2-pyridyl)imidazolidine-2-thiones (4a-g) with copper(II) chloride at an ambient temperature. The coordination modes of the complexes obtained were established by elemental analysis, IR spectroscopic data and single crystal X-ray diffraction studies. The in vitro cytotoxic activities of both the free ligands and copper(II) complexes were evaluated using a crystal violet microtiter plate assay on five human tumor cell lines: LCLC-103H, A-427, SISO, RT-4 and DAN-G. The free ligands 1-4 at concentration attainable in cancer cells of 20 μM showed no meaningful cytotoxic effect with cell viability in the range of 88%-100%. The most potent copper(II) complex of 1-(6-ethoxy-2-pyridyl)imidazolidin-2-one (6b) exhibited selective cytotoxicity against A-427 lung cancer cell line, while the complexes of 1-(5-methyl-2-pyridyl)imidazolidine-2-thione (5h) and 1-(4-tert-butyl-2-pyridyl)imidazolidine-2-thione (5j) showed cytostatic effect against a whole panel of five human tumor cell lines. In conclusion, the only complexes that showed remarkably increased activity in comparison to the free ligands were those obtained from N-(2-pyridyl)imidazolidine-2-thiones 4c and 4e substituted with alkyl group at position 4 or 5 of pyridine ring. PMID:25342555

  9. Visible-light-induced water oxidation by a hybrid photocatalyst consisting of bismuth vanadate and copper(II) meso-tetra(4-carboxyphenyl)porphyrin.

    PubMed

    Nakashima, Shu; Negishi, Ryo; Tada, Hiroaki

    2016-03-01

    Copper(II) meso-tetra(4-carboxyphenyl)porphyrin surface-modified monoclinic scheelite bismuth vanadate (CuTCPP/BiVO4) has been synthesized via a two-step route involving chemisorption of TCPP on BiVO4 and successive Cu(II) ion incorporation into the TCPP, and the surface modification drastically enhances the water oxidation to oxygen (O2) under visible-light irradiation (λ > 430 nm). PMID:26853997

  10. Single-Crystal to Single-Crystal Linker Substitution, Linker Place Exchange, and Transmetalation Reactions in Interpenetrated Pillared-Bilayer Zinc(II) Metal-Organic Frameworks.

    PubMed

    De, Dinesh; Neogi, Subhadip; Sañudo, E Carolina; Bharadwaj, Parimal K

    2015-11-23

    A twofold interpenetrated pillared-bilayer framework, {[Zn3 (L)2 (L2 )(DMF)]⋅(18DMF)(6H2 O)}n (1), has been synthesized from the ligands tris(4'-carboxybiphenyl)amine (H3 L) and 1,2-bis(4-pyridyl)ethylene (L2 ). The structure contains [Zn3 (COO)6 ] secondary building units (SBUs), in which three Zn(II) ions are almost linear with carboxylate bridging. This framework undergoes reversible pillar linker substitution reactions at the terminal Zn(II) centers with three different dipyridyl linkers of different lengths to afford three daughter frameworks, 2-4. Frameworks 2-4 are interconvertible through reversible linker substitution reactions. Also, competitive linker-exchange experiments show preferential incorporation of linker L3 in the parent framework 1. The larger linker L5 does not undergo such substitution reactions and framework 5, which contains this linker, can be synthesized solvothermally as a twofold interpenetrated structure. Interestingly, when framework 5 is dipped in a solution of L3 in DMF, linker substitution takes place as before, but linker L5 now moves and diagonally binds two Zn(II) centers to afford 6 as a nonpenetrated single framework. This linker place exchange reaction is unprecedented. All of these reactions take place in a single-crystal to single-crystal (SC-SC) manner, and have been observed directly through X-ray crystallography. In addition, each 3D framework undergoes complete copper(II) transmetalation. PMID:26462612

  11. Synthesis, spectral characterization, DNA binding ability and antibacterial screening of copper(II) complexes of symmetrical NOON tetradentate Schiff bases bearing different bridges

    NASA Astrophysics Data System (ADS)

    Bahaffi, Saleh O.; Abdel Aziz, Ayman A.; El-Naggar, Maher M.

    2012-08-01

    A novel series of four copper(II) complexes were synthesized by thermal reaction of copper acetate salt with symmetrical tetradentate Schiff bases, N,N'bis(o-vanillin)4,5-dimethyl-l,2-phenylenediamine (H2L1), N,N'bis(salicylaldehyde)4,5-dimethyl-1,2-phenylenediamine (H2L2), N,N'bis(o-vanillin)4,5-dichloro-1,2-phenylenediamine (H2L3) and N,N'bis(salicylaldehyde)4,5-dichloro-1,2-phenylenediamine (H2L4), respectively. All the new synthesized complexes were characterized by using of microanalysis, FT-IR, UV-Vis, magnetic measurements, ESR, and conductance measurements, respectively. The data revealed that all the Schiff bases (H2L1-4) coordinate in their deprotonated forms and behave as tetradentate NOON coordinated ligands. Moreover, their copper(II) complexes have square planar geometry with general formula [CuL1-4]. The binding of the complexes with calf thymus DNA (CT-DNA) was investigated by UV-Vis spectrophotometry, fluorescence quenching and viscosity measurements. The results indicated that the complexes bind to CT-DNA through an intercalative mode. From the biological activity view, the copper(II) complexes and their parent ligands were screened for their in vitro antibacterial activity against the bacterial species Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli and Pseudomonas aeruginosai by well diffusion method. The complexes showed an increased activity in comparison to some standard drugs.

  12. Copper(II) complexes with highly water-soluble L- and D-proline-thiosemicarbazone conjugates as potential inhibitors of Topoisomerase IIα.

    PubMed

    Bacher, Felix; Enyedy, Éva A; Nagy, Nóra V; Rockenbauer, Antal; Bognár, Gabriella M; Trondl, Robert; Novak, Maria S; Klapproth, Erik; Kiss, Tamás; Arion, Vladimir B

    2013-08-01

    Two proline-thiosemicarbazone bioconjugates with excellent aqueous solubility, namely, 3-methyl-(S)-pyrrolidine-2-carboxylate-2-formylpyridine thiosemicarbazone [L-Pro-FTSC or (S)-H2L] and 3-methyl-(R)-pyrrolidine-2-carboxylate-2-formylpyridine thiosemicarbazone [D-Pro-FTSC or (R)-H2L], have been synthesized and characterized by elemental analysis, one- and two-dimensional (1)H and (13)C NMR spectroscopy, and electrospray ionization mass spectrometry. The complexation behavior of L-Pro-FTSC with copper(II) in an aqueous solution and in a 30% (w/w) dimethyl sulfoxide/water mixture has been studied via pH potentiometry, UV-vis spectrophotometry, electron paramagnetic resonance, (1)H NMR spectroscopy, and spectrofluorimetry. By the reaction of copper(II) acetate with (S)-H2L and (R)-H2L in water, the complexes [Cu(S,R)-L] and [Cu(R,S)-L] have been synthesized and comprehensively characterized. An X-ray diffraction study of [Cu(S,R)-L] showed the formation of a square-pyramidal complex, with the bioconjugate acting as a pentadentate ligand. Both copper(II) complexes displayed antiproliferative activity in CH1 ovarian carcinoma cells and inhibited Topoisomerase IIα activity in a DNA plasmid relaxation assay. PMID:23829568

  13. N-ethyl-3-carbazolecarboxaldehyde-3-thiosemicarbazone: a new extractive spectrophotometric reagent for the determination of copper(II) in environmental and pharmaceutical samples.

    PubMed

    Reddy, K Janardhan; Kumar, J Rajesh; Narayana, S Lakshmi; Ramachandraiah, C; Thriveni, T; Reddy, A Varada

    2007-01-01

    N-ethyl-3-carbazolecarboxaldehyde-3-thio- semicarbazone (ECCT) as an new analytical reagent used for the development of a highly sensitive extractive spectrophotometric method for the determination of copper(II). The ECCT forms a greenish-yellow colored 1:1 (M:L) complex with copper(II) at pH 3.0, which is well extracted into n-butanol and shows maximum absorbance at 380 nm. The color of the complex is stable for more than forty eight hours. The system obey Beer's law in the range 0.4-3.6 with 2.243 x 10(4) l mol(-1) cm(-1), 2.83 x 10(-3) microg cm(-2) molar absorptivity and Sandell's sensitivity respectively. The regression coefficient is 0.412 with 0.99 correlation coefficient. The precision and accuracy of the method was checked by finding the relative standard deviation (0.422%). This developed method has been successfully employed for the determination of copper(II) in environmental and pharmaceutical samples. The method is evaluated by analyzing samples from the bureau of analyzed samples (BCS 233, 266, 216/1, 207 and 179) and by inter comparison of experimental values using AAS. PMID:16927197

  14. Antioxidant, DNA binding and nuclease activities of heteroleptic copper(II) complexes derived from 2-((2-(piperazin-1-yl)ethylimino)methyl)-4-substituted phenols and diimines

    NASA Astrophysics Data System (ADS)

    Ravichandran, J.; Gurumoorthy, P.; Imran Musthafa, M. A.; Kalilur Rahiman, A.

    2014-12-01

    A series of heteroleptic copper(II) complexes of the type [CuL1-4(diimine)](ClO4)2 (1-8) [L1-4 = 2-((2-(piperazin-1-yl)ethylimino)methyl)-4-substituted phenols, and diimine = 2,2‧-bipyridyl (bpy) or 1,10-phenanthroline (phen)], have been synthesized and characterized by spectroscopic methods. The IR spectra of complexes indicate the presence of uncoordinated perchlorate anions and the electronic spectra revealed the square pyramidal geometry with N4O coordination environment around copper(II) nuclei. Electrochemical studies of the mononuclear complexes evidenced one-electron irreversible reduction wave in the cathodic region. The EPR spectra of complexes with g|| (2.206-2.214) and A|| (154-172 × 10-4 cm-1) values support the square-based CuN3O coordination chromophore and the presence of unpaired electron localized in dx-y ground state. Antioxidant studies against DPPH revealed effective radical scavenging properties of the synthesized complexes. Binding studies suggest that the heteroleptic copper(II) complexes interact with calf thymus DNA (CT-DNA) through minor-groove and electrostatic interaction, and all the complexes display pronounced nuclease activity against supercoiled pBR322 DNA.

  15. Investigation of simultaneous biosorption of copper(II) and chromium(VI) on dried Chlorella vulgaris from binary metal mixtures: Application of multicomponent adsorption isotherms

    SciTech Connect

    Aksu, Z.; Acikel, U.; Kutsal, T.

    1999-02-01

    Although the biosorption of single metal ions to various kinds of microorganisms has been extensively studied and the adsorption isotherms have been developed for only the single metal ion situation, very little attention has been given to the bioremoval and expression of adsorption isotherms of multimetal ions systems. In this study the simultaneous biosorption of copper(II) and chromium(VI) to Chlorella vulgaris from a binary metal mixture was studied and compared with the single metal ion situation in a batch stirred system. The effects of pH and single- and dual-metal ion concentrations on the equilibrium uptakes were investigated. In previous studies the optimum biosorption pH had been determined as 4.0 for copper(II) and as 2.0 for chromium(VI). Multimetal ion biosorption studies were performed at these two pH values. It was observed that the equilibrium uptakes of copper(II) or chromium(VI) ions were changed due to the biosorption pH and the presence of other metal ions. Adsorption isotherms were developed for both single- and dual-metal ions systems at these two pH values, and expressed by the mono- and multicomponent Langmuir and Freundlich adsorption models. Model parameters were estimated by nonlinear regression. It was seen that the adsorption equilibrium data fitted very well to the competitive Freundlich model in the concentration ranges studied.

  16. Antioxidant, DNA binding and nuclease activities of heteroleptic copper(II) complexes derived from 2-((2-(piperazin-1-yl)ethylimino)methyl)-4-substituted phenols and diimines.

    PubMed

    Ravichandran, J; Gurumoorthy, P; Imran Musthafa, M A; Kalilur Rahiman, A

    2014-12-10

    A series of heteroleptic copper(II) complexes of the type [CuL(1-4)(diimine)](ClO4)2 (1-8) [L(1-4)=2-((2-(piperazin-1-yl)ethylimino)methyl)-4-substituted phenols, and diimine=2,2'-bipyridyl (bpy) or 1,10-phenanthroline (phen)], have been synthesized and characterized by spectroscopic methods. The IR spectra of complexes indicate the presence of uncoordinated perchlorate anions and the electronic spectra revealed the square pyramidal geometry with N4O coordination environment around copper(II) nuclei. Electrochemical studies of the mononuclear complexes evidenced one-electron irreversible reduction wave in the cathodic region. The EPR spectra of complexes with g|| (2.206-2.214) and A|| (154-172×10(-)(4)cm(-)(1)) values support the square-based CuN3O coordination chromophore and the presence of unpaired electron localized in [Formula: see text] ground state. Antioxidant studies against DPPH revealed effective radical scavenging properties of the synthesized complexes. Binding studies suggest that the heteroleptic copper(II) complexes interact with calf thymus DNA (CT-DNA) through minor-groove and electrostatic interaction, and all the complexes display pronounced nuclease activity against supercoiled pBR322 DNA. PMID:24998685

  17. Simultaneous and sensitive analysis of aliphatic carboxylic acids by ion-chromatography using on-line complexation with copper(II) ion.

    PubMed

    Kemmei, Tomoko; Kodama, Shuji; Yamamoto, Atsushi; Inoue, Yoshinori; Hayakawa, Kazuichi

    2015-01-01

    A new approach to ion chromatography is proposed to improve the UV detection of aliphatic carboxylic acids separated by anion-exchange chromatography. When copper(II) ion added to the mobile phase, it forms complexes with carboxylic acids that can be detected at 240 nm. The absorbance was found to increase with increasing copper(II) ion concentration. The retention times of α-hydroxy acids were also found to depend on the copper(II) ion concentration. Addition of acetonitrile to the mobile phase improved the separation of aliphatic carboxylic acids. The detection limits of the examined carboxylic acids (formate, glycolate, acetate, lactate, propionate, 3-hydroxypropionate, n-butyrate, isobutyrate, n-valerate, isovalerate, n-caproate) calculated at S/N=3 ranged from 0.06 to 3 μM. The detector signal was linear over three orders of magnitude of carboxylic acid concentration. The proposed method was successfully applied to analyze aliphatic carboxylic acids in rainwater and bread. PMID:25523885

  18. Nickel(II) complexes of pentadentate N5 ligands as catalysts for alkane hydroxylation by using m-CPBA as oxidant: a combined experimental and computational study.

    PubMed

    Sankaralingam, Muniyandi; Balamurugan, Mani; Palaniandavar, Mallayan; Vadivelu, Prabha; Suresh, Cherumuttathu H

    2014-09-01

    A new family of nickel(II) complexes of the type [Ni(L)(CH(3)CN)](BPh(4))(2), where L=N-methyl-N,N',N'-tris(pyrid-2-ylmethyl)-ethylenediamine (L1, 1), N-benzyl-N,N',N'-tris(pyrid-2-yl-methyl)-ethylenediamine (L2, 2), N-methyl-N,N'-bis(pyrid-2-ylmethyl)-N'-(6-methyl-pyrid-2-yl-methyl)-ethylenediamine (L3, 3), N-methyl-N,N'-bis(pyrid-2-ylmethyl)-N'-(quinolin-2-ylmethyl)-ethylenediamine (L4, 4), and N-methyl-N,N'-bis(pyrid-2-ylmethyl)-N'-imidazole-2-ylmethyl)-ethylenediamine (L5, 5), has been isolated and characterized by means of elemental analysis, mass spectrometry, UV/Vis spectroscopy, and electrochemistry. The single-crystal X-ray structure of [Ni(L(3))(CH(3)CN)](BPh(4))(2) reveals that the nickel(II) center is located in a distorted octahedral coordination geometry constituted by all the five nitrogen atoms of the pentadentate ligand and an acetonitrile molecule. In a dichloromethane/acetonitrile solvent mixture, all the complexes show ligand field bands in the visible region characteristic of an octahedral coordination geometry. They exhibit a one-electron oxidation corresponding to the Ni(II) /Ni(III) redox couple the potential of which depends upon the ligand donor functionalities. The new complexes catalyze the oxidation of cyclohexane in the presence of m-CPBA as oxidant up to a turnover number of 530 with good alcohol selectivity (A/K, 7.1-10.6, A=alcohol, K=ketone). Upon replacing the pyridylmethyl arm in [Ni(L1)(CH(3)CN)](BPh(4))(2) by the strongly σ-bonding but weakly π-bonding imidazolylmethyl arm as in [Ni(L5)(CH(3)CN)](BPh(4))(2) or the sterically demanding 6-methylpyridylmethyl ([Ni(L3)(CH(3)CN)](BPh(4))(2) and the quinolylmethyl arms ([Ni(L4)(CH(3)CN)](BPh(4))(2), both the catalytic activity and the selectivity decrease. DFT studies performed on cyclohexane oxidation by complexes 1 and 5 demonstrate the two spin-state reactivity for the high-spin [(N5)Ni(II)-O(.)] intermediate (ts1(hs), ts2(doublet)), which has a low-spin state located closely in

  19. Synthesis, characterization, and tyrosinase biomimetic catalytic activity of copper(II) complexes with schiff base ligands derived from α-diketones with 2-methyl-3-amino-(3 H)-quinazolin-4-one

    NASA Astrophysics Data System (ADS)

    Ramadan, Abd El-Motaleb M.; Ibrahim, Mohamed M.; Shaban, Shaban Y.

    2011-12-01

    A template condensation of α-diketones (biacetyl, benzile and 2,3-pentanedione) with 2-methyl-3-amino-(3 H)-quinazolin-4-one (AMQ) in the presence of CuX 2 (X = Cl -, Br -, NO3- or ClO4-) resulted in the formation of tetradentate Schiff base copper(II) complexes of the type [CuLX]X and [CuL]X 2. Structural characterization of the complex species was achieved by several physicochemical methods, namely elemental analysis, electronic spectra, IR, ESR, molar conductivity, thermal analysis (TAG & DTG), and magnetic moment measurements. The stereochemistry, the nature of the metal chelates, and the catalytic reactivity are markedly dependent upon the type of counter anions and the ligand substituent within the carbonyl moiety. A square planar monomeric structure is proposed for the perchlorate, nitrate, and bromide complexes, in which the counter anions are loosely bonded to copper(II) ion. For the chloride complexes, the molar conductivities and the spectral data indicated that they have square-pyramidal environments around copper(II) center. The reported copper(II) complexes exhibit promising tyrosinase catalytic activity towards the hydroxylation of phenol followed by the aerobic oxidation of the resulting catechol. A linear correlation almost exists between the catalytic reactivity and the Lewis-acidity of the central copper(II) ion created by the donating properties of the parent ligand. The steric considerations could be accounted to clarify the difference in the catalytic activity of these functional models.

  20. Surface directed reversible imidazole ligation to nickel(ii) octaethylporphyrin at the solution/solid interface: a single molecule level study.

    PubMed

    Nandi, Goutam; Chilukuri, Bhaskar; Hipps, K W; Mazur, Ursula

    2016-07-27

    Scanning tunneling microscopy (STM) is used to study for the first time the reversible binding of imidazole (Im) and nickel(ii) octaethylporphyrin (NiOEP) supported on highly oriented pyrolytic graphite (HOPG) at the phenyloctane/NiOEP/HOPG interface at 25 °C. The ligation of Im to the NiOEP receptor while not observed in fluid solution is readily realized at the solution/HOPG interface. The coordination process scales with increasing Im concentration and can be effectively modeled by the Langmuir isotherm. At room temperature it is determined that the standard free energy of adsorption is ΔGc = -15.8 kJ mol(-1) and the standard enthalpy of adsorption is estimated to be ΔHc ≈ -80 kJ mol(-1). The reactivity of imidazole toward NiOEP adsorbed on HOPG is attributed to charge donation from the graphite stabilizing the Im-Ni bond. This charge transfer pathway is supported by molecular and periodic modeling calculations which indicate that the Im ligand behaves as a π-acceptor. DFT calculations also show that the nickel ion in the Im-NiOEP/HOPG complex is in a singlet ground state. This is surprising since both our calculations and previous experimental studies find a triplet ground state for the five and six coordinated Im-nickel(ii) porphyrins in the gas-phase or in solution. Both the experimental and the theoretical findings provide information that is useful for better understanding of chemical sensing/recognition and catalytic processes that utilize metal-organic complexes adsorbed on surfaces where the reactivity of the metal is moderated by the substrate. PMID:27416994

  1. Synthesis, structure, DNA/BSA interaction and in vitro cytotoxic activity of nickel(II) complexes derived from S-allyldithiocarbazate.

    PubMed

    Nanjundan, Nanjan; Selvakumar, Ponnusamy; Narayanasamy, Ramaswamy; Haque, Rosenani A; Velmurugan, Krishnaswamy; Nandhakumar, Raju; Silambarasan, Tamilselvan; Dhandapani, Ramamurthy

    2014-12-01

    Two nickel(II) complexes with formula NiL1 and NiL2 (HL1 = S-allyl-4-methoxybenzylidene hydrazinecarbodithioate, HL2 = S-allyl-1-napthylidenehydrazinecarbodithioate) have been synthesized and characterized by elemental analysis, FT-IR, NMR, UV-vis spectroscopy and ESI mass spectrometry. The crystal structure of complex 1 has been determined by single crystal X-ray diffractometry. Both HL1 and HL2 ligands are coordinated to the metal in thiolate form. In complexes, squareplanar geometry of the nickel is coordinated with two bidentate ligand units acting through azomethine nitrogen and thiolato sulfur atoms. To explore the potential medicinal value of the complexes with calf thymus DNA and bovine serum albumin (BSA) were studied at normal physiological conditions using fluorescence spectral techniques. The DNA binding constant values of the complexes were found in the range from 5.02 × 10(4), 3.54 × 10(4), and the binding affinities are in the following order 1 > 2. In addition, nickel complexes 1 and 2 shows better binding propensity to the bovine serum albumin (BSA) protein, giving a Ksv value 5.8 × 10(4), 4.47 × 10(4) respectively. From the oxidative cleavage of the complexes with pBR322 DNA, it is inferred that the effects of cleavage are dose-dependent. In addition, in vitro cytotoxicity of the complexes assayed against Vero and HeLa cell lines have shown higher cytotoxic activity with the lower IC50 values indicating their efficiency in killing cancer cells even at various concentrations. PMID:25463665

  2. Synthesis and characterization of a nickel(II) complex of 9-methoxy-2,3-dihydro-1,4-benzoxyzepine derived from a Schiff base ligand and its ligand substitution reaction

    NASA Astrophysics Data System (ADS)

    Saha, Sudeshna; Kottalanka, Ravi K.; Bhowmik, Prasanta; Jana, Subrata; Harms, Klaus; Panda, Tarun K.; Chattopadhyay, Shouvik; Nayek, Hari Pada

    2014-03-01

    A Schiff base ligand (2-{(E)-[2-bromoethyl)imino]methyl}-6-methoxy phenol (LH) has been synthesized and characterized by NMR, IR spectroscopy and elemental analysis. The reaction of LH with nickel acetate tetrahydrate results in the formation of a nickel(II) complex (1). The ligand (LH) has been converted into a heterocyclic moiety, 9-methoxy-2,3-dihydro-1,4-benzoxyzepine (L) in 1 and coordinated to nickel(II) ion. Ligand substitution reaction of 1 with 3-aminopyridine leads to the formation of 3-aminopyridine derivative of complex 1, [{3-(NH2-Py)}4Ni(H2O)2]Br2ṡ2(CH2Cl2) (2). Complexes 1 and 2 were characterized by using standard analytical techniques and their solid-state structures were confirmed by single crystal X-ray diffraction studies. Complex 1 crystallizes in orthorhombic space group Pccn with cell dimensions of a = 7.8483(10) Å, b = 30.662(3) Å, c = 9.3872(11) Å, Z = 4 and complex 2 crystallizes in orthorhombic space group Fddd with cell dimensions of a = 8.8108(4) Å, b = 21.0583(11) Å, c = 34.1913(17) Å, Z = 8. The optical properties and thermogravimetric analyses of complexes 1 and 2 are also reported.

  3. Copper(II) imidazolate frameworks as highly efficient photocatalysts for reduction of CO{sub 2} into methanol under visible light irradiation

    SciTech Connect

    Li, Jingtian; Luo, Deliang; Yang, Chengju; He, Shiman; Chen, Shangchao; Lin, Jiawei; Zhu, Li; Li, Xin

    2013-07-15

    Three copper(II) imidazolate frameworks were synthesized by a hydrothermal (or precipitation) reaction. The catalysts were characterized by X-ray diffraction (XRD), nitrogen adsorption, transmission electron microscopy (TEM), ultraviolet–visible spectroscopy (UV–vis), Fourier transform infrared spectra (FTIR), thermogravimetry (TG). Meanwhile, the photocatalytic activities of the samples for reduction of CO{sub 2} into methanol and degradation of methylene blue (MB) under visible light irradiation were also investigated. The results show that the as-prepared samples exhibit better photocatalytic activities for the reduction of carbon dioxide into methanol with water and degradation of MB under visible light irradiation. The orthorhombic copper(II) imidazolate frameworks with a band gap of 2.49 eV and green (G) color has the best photocatalytic activity for reduction of CO{sub 2} into methanol, 1712.7 μmol/g over 5 h, which is about three times as large as that of monoclinic copper(II) imidazolate frameworks with a band gap 2.70 eV and blue (J) color. The degradation kinetics of MB over three photocatalysts fitted well to the apparent first-order rate equation and the apparent rate constants for the degradation of MB over G, J and P (with pink color) are 0.0038, 0.0013 and 0.0016 min{sup −1}, respectively. The synergistic effects of smallest band gap and orthorhombic crystal phase structure are the critical factors for the better photocatalytic activities of G. Moreover, three frameworks can also be stable up to 250 °C. The investigation of Cu-based zeolitic imidazolate frameworks maybe provide a design strategy for a new class of photocatalysts applied in degradation of contaminations, reduction of CO{sub 2}, and even water splitting into hydrogen and oxygen under visible light. - Graphical abstract: Carbon dioxide was reduced into methanol with water over copper(II) imidazolate frameworks under visible light irradiation. - Highlights: • Three copper(II

  4. Three tetranuclear copper(II) cluster-based complexes constructed from 4-amino-1,2,4-triazole and different aromatic carboxylates: Assembly, structures, electrochemical and magnetic properties

    SciTech Connect

    Wang, Xiu-Li; Zhao, Wei; Zhang, Ju-Wen; Lu, Qi-Lin

    2013-02-15

    Three new tetranuclear copper(II) cluster-based complexes constructed from 4-amino-1,2,4-triazole (atrz) and three types of aromatic carboxylates, [Cu{sub 4}({mu}{sub 3}-OH){sub 2}(atrz){sub 2}(DNBA){sub 6}] (1), [Cu{sub 4}({mu}{sub 3}-OH){sub 2}(atrz){sub 2}(1,3-BDC){sub 3}]{center_dot}2H{sub 2}O (2) and [Cu{sub 4}({mu}{sub 3}-OH){sub 2}(atrz){sub 2}(SIP){sub 2}]{center_dot}4H{sub 2}O (3) (HDNBA=3,5-dinitrobenzoic acid, 1,3-H{sub 2}BDC=1,3-benzenedicarboxylic acid and NaH{sub 2}SIP=sodium 5-sulfoisophthalate), have been hydrothermally synthesized and structurally characterized. Complex 1 displays a single-molecular Cu{sup II}{sub 4} cluster structure, which is further connected by the intermolecular hydrogen-bonding interactions to form a 2D supramolecular layer. In 2, there also exist tetranuclear Cu{sup II}{sub 4} clusters, which are linked by the 1,3-BDC anions to give a 3D NaCl-type framework. In 3, the Cu{sup II}{sub 4} clusters are connected by the carboxyl and sulfo groups of SIP anions to generate 3D (4,8)-connected framework with a (4{sup 10}{center_dot}6{sup 14}{center_dot}8{sup 4})(4{sup 5}{center_dot}6){sub 2} topology. The atrz ligand conduces to the construction of tetranuclear copper(II) clusters and the carboxylates with different non-carboxyl substituent show important effects on the final structures of the title complexes. The electrochemical and magnetic properties of 1-3 have been investigated. - Graphical abstract: Three tetranuclear copper(II) cluster-based complexes based on different carboxylates have been synthesized under hydrothermal conditions. The carboxylate anions play a key role in the formation of three different structures. Highlights: Black-Right-Pointing-Pointer Three new tetranuclear copper(II) cluster-based complexes have been obtained. Black-Right-Pointing-Pointer The atrz conduces to the construction of tetranuclear copper(II) clusters. Black-Right-Pointing-Pointer Carboxylates show important effect on the structures of

  5. Determination of Zinc(II) Ions Released into Artificial Digestive Juices from Culinary-Medicinal Button Mushroom, Agaricus bisporus (Agaricomycetidae), Biomass of In Vitro Cultures Using an Anodic Stripping Voltammetry Method.

    PubMed

    Kala, Katarzyna; Muszynska, Bozena; Zajac, Magdalena; Krezalek, Remigiusz; Opoka, Wlodzimierz

    2016-01-01

    Zinc is one of those microelements that are essential for the proper functioning of the human body and must be supplemented in our food at a daily dose of 15 mg. It is well known that mushrooms accumulate elements; thus, in order to determine the extent of accumulation and the level of zinc released from mushrooms, in vitro cultures of Agaricus bisporus were established. The cultures were run on a modified Oddoux medium (a control culture) as well as on the same medium with the addition of zinc hydroaspartate (100 and 200 mg/L) and zinc sulfate (87.23 and 174.47 mg/L). These compounds were chosen to help estimate which form, organic or inorganic, results in a better assimilation of zinc(II) ions by biomass. As the next step, the level of zinc(II) ions released from the lyophilized biomass of in vitro cultures to the digestive juices, under thermal conditions of the human body (37°C), was determined. For this purpose, artificial digestive juices, imitating the composition of human digestive juices, were used. For determination of zinc(II) ions in the digestive tract, an anodic stripping voltammetry method was employed. The amount of zinc released into artificial saliva over 1 minute varied from 0.15 mg/100 g d.w. in the control culture to 2.35 mg/100 g d.w. in the biomass in the medium to which 200 mg/L zinc hydroaspartate had been added. Values were higher in gastric juice and depended on incubation time (2.66 to 30.63 mg/100 g d.w.). In intestinal juice, the highest value of the released zinc grew to 24.20 mg/100 g d.w. (biomass of A. bisporus in vitro cultures in medium with the addition of 200 mg/L zinc hydroaspartate). Total average amount of zinc released into artificial digestive juices was the highest (56.26 mg/100 g d.w.) from A. bisporus biomass of in vitro cultures in the medium to which 200 mg/L zinc hydroaspartate had been added. PMID:27279537

  6. Syntheses of vanadyl and zinc(II) complexes of 1-hydroxy-4,5,6-substituted 2(1H)-pyrimidinones and their insulin-mimetic activities.

    PubMed

    Yamaguchi, Mika; Wakasugi, Kei; Saito, Ryota; Adachi, Yusuke; Yoshikawa, Yutaka; Sakurai, Hiromu; Katoh, Akira

    2006-02-01

    Control of the glucose level in the blood plasma has been achieved in vitro and in vivo by administration of vanadium and zinc in form of inorganic salts. It has been shown that elements are poorly absorbed in their inorganic forms and required high doses which have been associated with undesirable side effects. Many researchers, therefore, have focused on metal complexes that were prepared from VOSO(4) or ZnSO(4) and low-molecular-weight bidentate ligands. Seven kinds of 1-hydroxy-4,6-disubstituted and 1-hydroxy-4,5,6-trisubstituted-2(1H)-pyrimidinones were synthesized by reaction of N-benzyloxyurea and beta-diketones and subsequent removal of the protecting group. Six kinds of 1-hydroxy-4-(substituted)amino-2(1H)-pyrimidinones were synthesized by the substitution reaction of 1-benzyloxy-4-(1',2',4'-triazol-1'-yl)-2(1H)-pyrimidinone with various alkyl amines or amino acids. Treatment with VOSO(4) and ZnSO(4) or Zn(OAc)(2) afforded vanadyl(IV) and zinc(II) complexes which were characterized by means of (1)H NMR, IR, EPR, and UV-vis spectroscopies, and combustion analysis. The in vitro insulin-mimetic activity of these complexes was evaluated from 50% inhibitory concentrations (IC(50)) on free fatty acid (FFA) release from isolated rat adipocytes treated with epinephrine. Vanadyl complexes of 4,6-disubstituted-2(1H)-pyrimidinones showed higher insulin-mimetic activities than those of 4,5,6-trisubstituted ones. On the other hand, Zn(II) complexes showed lower insulin-mimetic activities than VOSO(4) and ZnSO(4) as positive controls. It was found that the balance of the hydrophilicity and/or hydrophobicity is important for higher insulin-mimetic activity. The in vivo insulin-mimetic activity was evaluated with streptozotocin (STZ)-induced diabetic rats. Blood glucose levels were lowered from hyperglycemic to normal levels after the treatment with bis(1,2-dihydro-4,6-dimethyl-2-oxo-1-pyrimidinolato)oxovanadium(IV) by daily intraperitoneal injections. The improvement in

  7. Some new nano-structure zinc(II) coordination compounds of an imidazolidine Schiff base: Spectral, thermal, antimicrobial properties and DNA interaction

    NASA Astrophysics Data System (ADS)

    Montazerozohori, Morteza; Musavi, Sayed Alireza; Naghiha, Asghar; Zohour, Mostafa Montazer

    2014-08-01

    Some novel nano-sized structure zinc complexes of a new Schiff base ligand entitled as (3-nitro-benzylidene)-{2-[2-(3-nitro-phenyl)-imidazolidine-1-yl]-ethyl}-amine(L) with general formula of ZnLX2 wherein X = Cl-, Br-, I-, SCN- and N3- have been synthesized under ultrasonic conditions. The ligand and its complexes have been characterized by elemental analysis, molar conductance measurements, FT-IR, 1H and 13C NMR and UV-Visible spectroscopy. The resulting data from spectral investigation especially 1H and 13C NMR well confirmed formation of an imidazolidine ring in the ligand structure. Transmission electron microscopy (TEM) showed nano-size structures with average particle sizes of 21.80-78.10 nm for the zinc(II) Schiff base complexes. The free Schiff base and its Zn(II) complexes have been screened in vitro both for antibacterial activity against some gram-positive and gram-negative bacteria and also for antifungal activity. The metal complexes were found to be more active than the free Schiff base ligand. The results showed that ZnL(N3)2 is the most effective inhibitor against Escherichia coli, Pseudomonas aereuguinosa, Staphylococcus aureus and Candida albicans while ZnLBr2 was found to be more effective against Bacillus subtillis than other compounds. Moreover, DNA cleavage potential of all compounds with plasmid DNA was investigated. The results showed that the ligand and ZnLCl2 complex cleave DNA more efficiently than others. In final, thermal analysis of ligand and its complexes revealed that they are decomposed via 2-3 thermal steps in the range of room temperature to 1000 °C. Furthermore some activation kinetic parameters such as A, E*, ΔH*, ΔS* and ΔG* were calculated based on TG/DTA plots by use of coats - Redfern relation. Positive values of activation energy evaluated for the compounds confirmed the thermal stability of them. In addition to, the positive ΔH*, and ΔG* values suggested endothermic character for the thermal decomposition steps.

  8. Photophysical properties of long rodlike meso-meso-linked zinc(II) porphyrins investigated by time-resolved laser spectroscopic methods.

    PubMed

    Kim, Y H; Jeong, D H; Kim, D; Jeoung, S C; Cho, H S; Kim, S K; Aratani, N; Osuka, A

    2001-01-10

    The molecular design of directly meso-meso-linked porphyrin arrays as a new model of light-harvesting antenna as well as a molecular photonic wire was envisaged to bring the porphyrin units closer for rapid energy transfer. For this purpose, zinc(II) 5,15-bis(3,5-bis(octyloxy)phenyl)porphyrin (Z1) and its directly meso-meso-linked porphyrin arrays up to Z128 (Zn, n represents the number of porphyrins) were synthesized. The absorption spectra of these porphyrin arrays change in a systematic manner with an increase in the number of porphyrins; the high-energy Soret bands remain at nearly the same wavelength (413-414 nm), while the low-energy exciton split Soret bands are gradually red-shifted, resulting in a progressive increase in the exciton splitting energy. The exciton splitting is nicely correlated with the values of cos[pi/(N + 1)] according to Kasha's exciton coupling theory, providing a value of 4250 cm(-1) for the exciton coupling energy in the S(2) state. The increasing red-shifts for the Q-bands are rather modest. The fluorescence excitation anisotropy spectra of the porphyrin arrays show that the photoexcitation of the high-energy Soret bands exhibits a large angle difference between absorption and emission dipoles in contrast with the photoexcitation of the low-energy exciton split Soret and Q-bands. This result indicates that the high-energy Soret bands are characteristic of the summation of the individual monomeric transitions with its overall dipole moment deviated from the array chain direction, while the low-energy Soret bands result from the exciton splitting between the monomeric transition dipoles in line with the array chain direction. From the fluorescence quantum yields and fluorescence lifetime measurements, the radiative coherent length was estimated to be 6-8 porphyrin units in the porphyrin arrays. Ultrafast fluorescence decay measurements show that the S(2) --> S(1) internal conversion process occurs in less than 1 ps in the porphyrin

  9. New mixed ligand zinc(II) complexes based on the antiepileptic drug sodium valproate and bioactive nitrogen-donor ligands. Synthesis, structure and biological properties.

    PubMed

    Darawsheh, Mohanad; Abu Ali, Hijazi; Abuhijleh, A Latif; Rappocciolo, Emilia; Akkawi, Mutaz; Jaber, Suhair; Maloul, Salam; Hussein, Yasmeen

    2014-07-23

    Starting from the precursor [Zinc Valproate complex] (1), new mixed ligand zinc(II) complexes of valproic acid and nitrogen-based ligands, formulating as, [Zn(valp)22,9-dmphen] (2), [Zn2(valp)4(quin)2] (3), [Zn(valp)2(2-ampy)2] (4), and [Zn(valp)2(2-ampic)2] (5) (valp = valproate, 2,9-dmphen = 2,9-dimethyl-1,10-phenanthroline, quin = quinoline, 2-ampy = 2-aminopyridine, 2-ampic = 2-amino-6-picoline) were synthesized and characterized using IR, (1)H NMR, (13)C{(1)H} NMR and UV-Vis spectrometry. The crystal structures of complexes 2, 3 and 4 were determined using single-crystal X-ray diffraction. The complexes were also evaluated for their anti-bacterial activity using in-vitro agar diffusion method against three Gram-positive (Micrococcus luteus, Staphylococcus aureus, and Bacillus subtilis) and three Gram-negative (Escherichia coli, Klebsiella pneumoniae, and Proteus mirabilis) species. Complex 2 showed considerable activity against all tested microorganisms and the effect of complexation on the anti-bacterial activity of the parent ligand of 2 was also investigated. The anti-bacterial activity of 2,9-dmphen against Gram-negative bacteria was enhanced upon complexation with zinc valproate. On the other hand, complexes 1 and 3 showed weak inhibition activity against the tested species and complexes 4 and 5 didn't show any activity at all. Two methods were used for testing the inhibition of ferriprotoporphyrinIX bio-mineralization: a semi-quantitative micro-assay and a previously self-developed quantitative in-vitro method. Both were used to study the efficiency of these complexes in inhibiting the formation of the Malaria pigment which considered being the target of many known anti-malarial drugs such as Chloroquine and Amodiaquine. Results showed that the efficiency of complex 2 in preventing the formation of β-Hematin was 80%. The efficiency of Amodiaquine as a standard drug was reported to give 91%. PMID:24904962

  10. Magneto-structural versatility of copper(II)-3-phenylpropionate coordination polymers with N-donor coligands.

    PubMed

    de Campos, Nathália R; Ribeiro, Marcos A; Oliveira, Willian X C; Reis, Daniella O; Stumpf, Humberto O; Doriguetto, Antônio C; Machado, Flávia C; Pinheiro, Carlos B; Lloret, Francesc; Julve, Miguel; Cano, Joan; Marinho, Maria V

    2016-01-01

    A novel series of copper(II) coordination polymers [Cu2(O2CC8H9)4(pyz)]n (1), [Cu2(O2CC8H9)4(dps)]n (2), {[Cu(O2CC8H9)2(dps)(H2O)]·H2O}n (3), {[NaCu(O2CC8H9)2(bpm)(NO3)]·H2O}n (4), and [Cu4(O2CC8H9)6(OH)2(bpp)2]n (5) [O2CC8H9− = 3-phenylpropionate anion, pyz = pyrazine, dps = di(4-pyridyl)sulfide, bpm = 2,2′-bipyrimidine, and bpp = 1,3-bis(4-pyridyl)propane] have been synthesized and magneto-structurally investigated. Compounds 1 and 2 belong to a large group of copper(II) carboxylates where bis-monodentate pyz (1) and dps (2) ligands connect the paddle-wheel [CuII2(μ-O2CC8H9)4] units leading to alternating copper(II) chains. The structure of 3 consists of uniform chains of trans-[CuII(O2CC8H9)2] units linked by the bis-monodentate dps ligand. Compound 4 consists of heterobimetallic chains where [NaI2CuII2(μ-O2CC8H9)4(NO3)2] units are doubly bridged by bis-bidentate bpm ligands. Compound 5 is also a chain compound whose structure is made up by tetranuclear [CuII4(μ3-OH)2(μ-O2CC8H9)4(O2CC8H9)2] units which are doubly bridged by bis-monodentate bpp ligands. The magnetic properties were investigated in the temperature range 1.8–300 K. Strong antiferromagnetic interactions across the quadruple syn–syn carboxylate are observed in 1 and 2 [J = −378 (1) and −348 cm−1 (2)] whereas a weak ferromagnetic coupling through the double out-of-plane oxo(carboxylate) bridge occurs in 4 [J = +2.66 cm−1], the spin Hamiltonian being defined as H = −JS1·S2 with S1 = S2 = SCu = 1/2. A quasi Curie law is observed for 3 (θ = −0.36 cm−1), the bis-monodentate dps ligand being a very poor mediator of magnetic interactions. The analysis of the magnetic properties of 5 is quite complex because of the presence of two crystallographically independent tetracopper(II) units with single-μ-hydroxo, di-μ-hydroxo, μ3-hydroxo and single-μ-hydroxo plus double syn,syn carboxylate bridges in each one. The nature and values of the magnetic couplings for 5 obtained by

  11. Experimental investigation on the mechanism of chelation-assisted, copper(II) acetate-accelerated azide-alkyne cycloaddition.

    PubMed

    Kuang, Gui-Chao; Guha, Pampa M; Brotherton, Wendy S; Simmons, J Tyler; Stankee, Lisa A; Nguyen, Brian T; Clark, Ronald J; Zhu, Lei

    2011-09-01

    A mechanistic model is formulated to account for the high reactivity of chelating azides (organic azides capable of chelation-assisted metal coordination at the alkylated azido nitrogen position) and copper(II) acetate (Cu(OAc)(2)) in copper(II)-mediated azide-alkyne cycloaddition (AAC) reactions. Fluorescence and (1)H NMR assays are developed for monitoring the reaction progress in two different solvents, methanol and acetonitrile. Solvent kinetic isotopic effect and premixing experiments give credence to the proposed different induction reactions for converting copper(II) to catalytic copper(I) species in methanol (methanol oxidation) and acetonitrile (alkyne oxidative homocoupling), respectively. The kinetic orders of individual components in a chelation-assisted, copper(II)-accelerated AAC reaction are determined in both methanol and acetonitrile. Key conclusions resulting from the kinetic studies include (1) the interaction between copper ion (either in +1 or +2 oxidation state) and a chelating azide occurs in a fast, pre-equilibrium step prior to the formation of the in-cycle copper(I)-acetylide, (2) alkyne deprotonation is involved in several kinetically significant steps, and (3) consistent with prior experimental and computational results by other groups, two copper centers are involved in the catalysis. The X-ray crystal structures of chelating azides with Cu(OAc)(2) suggest a mechanistic synergy between alkyne oxidative homocoupling and copper(II)-accelerated AAC reactions, in which both a bimetallic catalytic pathway and a base are involved. The different roles of the two copper centers (a Lewis acid to enhance the electrophilicity of the azido group and a two-electron reducing agent in oxidative metallacycle formation, respectively) in the proposed catalytic cycle suggest that a mixed valency (+2 and +1) dinuclear copper species be a highly efficient catalyst. This proposition is supported by the higher activity of the partially reduced Cu(OAc)(2) in

  12. Copper(II) complexes of terminally free alloferon mutants containing two histidyl binding sites inside peptide chain structure and stability.

    PubMed

    Kadej, Agnieszka; Kuczer, Mariola; Kowalik-Jankowska, Teresa

    2015-12-21

    Mononuclear and polynuclear copper(II) complexes of alloferon 1 with point mutations, H1A/H12A H2N-A(1)GVSGH(6)GQH(9)GVA(12)G-COOH, H1A/H9A H2N-A(1)GVSGH(6)GQA(9)GVH(12)G-COOH, and H1A/H6A H2N-A(1)GVSGA(6)GQH(9)GVH(12)G-COOH, have been studied by potentiometric, UV-visible, CD, and EPR spectroscopy, and mass spectrometry (MS) methods. Complete complex speciation at different metal-to-ligand molar ratios ranging from 1 : 1 to 3 : 1 was obtained. Over a wide 6-8 pH range, including physiological pH 7.4, and a 1 : 1 metal-to-ligand molar ratio, the peptides studied formed a CuH-1L complex with the 4N{NH2,N(-),2NIm} coordination mode. The presence of the 4N binding site for the CuH-1L complexes prevented the deprotonation and coordination of the second amide nitrogen atom to copper(II) ions (pK-1/-2 7.83-8.07) compared to that of pentaGly (6.81). The amine nitrogen donor and two imidazole nitrogen atoms (H(6)H(9), H(6)H(12) and H(9)H(12)) can be considered to be independent metal-binding sites in the species formed. As a consequence, di- and trinuclear complexes for the metal-to-ligand 2 : 1 and 3 : 1 molar ratios dominate in the solution, respectively. For the Cu(II)-H1A/H9A and Cu(II)-H1A/H12A systems, the Cu3H-9L complexes are likely formed by the coordination of amide nitrogen atoms towards C-termini with ring sizes (7,5,5). PMID:26565558

  13. Quantification of Outer-Sphere Macrochelate Formation in the Ternary cis-Diammine-Platinum(II)-Bis-2'-deoxyguanosine 5'-Monophosphate Complex, cis-(NH(3))(2)Pt(dGMP)(2)(2)(-), and Formation of Quaternary Mixed Metal Ion Species with Magnesium(II), Copper(II), or Zinc(II) in Aqueous Solution.

    PubMed

    Song, Bin; Oswald, Gerda; Zhao, Jing; Lippert, Bernhard; Sigel, Helmut

    1998-09-21

    The acid-base properties of cis-(NH(3))(2)Pt(dG)(2)(2)(-), where both dG(2)(-) (=2'-deoxyguanosine 5'-monophosphate) are N7-coordinated to the same Pt(II) [the complex is abbreviated as Pt(dG)(2)(2)(-)], are summarized [on the basis of potentiometric pH titration data from B. Song et al. (Metal-Based Drugs 1996, 3, 131-141)] and a micro acidity constant scheme is developed which allows quantification of the intrinsic acidity of the two P(O)(2)(OH)(-) groups present in this ternary complex (I = 0.1 M, NaNO(3); 25 degrees C). On the basis of comparisons with the corresponding acid-base properties of cis-(NH(3))(2)Pt(dCMP.H-N3)(2) [(dCMP.H)(-) = phosphate-monoprotonated 2'-deoxycytidine 5'-monophosphate] it is concluded that intramolecular, outer-sphere macrochelates form via Pt(NH(3)).O(3)P hydrogen bonds. The formation degree of these macrochelates is quantified; it amounts in aqueous solution in each case (in its lower limit) to about 40% for the various possibilities which exist for the formation of these chelates in the cis-(NH(3))(2)Pt(dG)(2) complexes. The stability constants of the mixed metal ion complexes, M[Pt(H;dG)(dG)](+) and M[Pt(dG)(2)], were also determined via potentiometric pH titrations. On the basis of previous measurements with simple phosphate monoesters and phosphonate derivatives, i.e., R-PO(3)(2)(-) with R being a noncoordinating residue (Sigel, H.; et al., Helv. Chim. Acta 1992, 75, 2634-2656), it is shown that the stability of the two mixed metal ion complexes is largely governed by the basicity of the phosphate groups (as quantified via the mentioned microconstants) indicating that the effect of the N7-bound Pt(II) on the phosphate-metal ion binding properties is relatively small. These results suggest that, e.g., a metal ion bound to a nucleobase residue in a nucleotide or in a nucleic acid affects only slightly the metal ion binding capabilities of its phosphate residue or its phosphate backbone. PMID:11670649

  14. The binding of manganese(II) and zinc(II) to the synthetic oligonucleotide d(C-G-C-G-A-A-T-T-C-G-C-G)2. A 1H NMR study.

    PubMed

    Frøystein, N A; Sletten, E

    1991-03-01

    The interaction of the synthetic oligonucleotide d(C-G-C-G-A-A-T-T-C-G-C-G)2 with two different transition-metal ions has been investigated in aqueous solution by means of 1H NMR spectroscopy. The effects on the DNA due to the presence of manganese(II) or zinc(II) have been monitored by observing the paramagnetic broadening and diamagnetic shifts of the non-exchangeable proton resonance lines, respectively. The 1H NMR spectra acquired during the course of the manganese(II) titration show very distinct broadening effects on certain DNA resonance lines. Primarily, the H8 resonance of G4 is affected, but also the H5 and H6 resonances of C3 are clearly affected by the metal. The results imply that the binding of manganese(II) to DNA is sequence specific. The 1H spectra obtained during the zinc(II) titration reveal diamagnetic shift effects which largely conform with the paramagnetic broadening effects due to the presence of manganese(II), although this picture is somewhat more complex. The H8 resonance of G4 displays a clearly visible high-field shift, while for the other guanosine H8 protons this effect is absent. The H1' and H2' protons of C3 show an effect of similar strength, although in the opposite direction, while H5 and H6 of C3 are only slightly affected. Local differences in the structure of the DNA and the basicities of potential binding sites on different base steps in the sequence might account for the observed sequence selectivity. PMID:2039665

  15. Trapping of muscle relaxant methocarbamol degradation product by complexation with copper(II) ion: spectroscopic and quantum chemical studies.

    PubMed

    Mansour, Ahmed M; Shehab, Ola R

    2014-07-15

    Structural properties of methocarbamol (Mcm) were extensively studied both experimentally and theoretically using FT IR, (1)H NMR, UV-Vis., geometry optimization, Mulliken charge, and molecular electrostatic potential. Stability arises from hyper-conjugative interactions, charge delocalization and H-bonding was analyzed using natural bond orbital (NBO) analysis. Mcm was decomposed in ethanol/water mixture at 80°C to guaifenesin [(RS)-3-(2-methoxyphenoxy)propane-1,2-diol] and carbamate ion [NH2COO(-)], where the degradation mechanism was explained by trapping the carbamate ion via the complexation with copper(II) ion. The structure of the isolated complex ([Cu(NH2COO)2(H2O)]⋅4H2O) was elucidated by spectral, thermal, and magnetic tools. Electronic spectra were discussed by TD-DFT and the descriptions of frontier molecular orbitals and the relocations of the electron density were determined. Calculated g-tensor values showed best agreement with experimental values from EPR when carried out using both the B3LYP and B3PW91 functional. PMID:24674917

  16. Trapping of muscle relaxant methocarbamol degradation product by complexation with copper(II) ion: Spectroscopic and quantum chemical studies

    NASA Astrophysics Data System (ADS)

    Mansour, Ahmed M.; Shehab, Ola R.

    2014-07-01

    Structural properties of methocarbamol (Mcm) were extensively studied both experimentally and theoretically using FT IR, 1H NMR, UV-Vis., geometry optimization, Mulliken charge, and molecular electrostatic potential. Stability arises from hyper-conjugative interactions, charge delocalization and H-bonding was analyzed using natural bond orbital (NBO) analysis. Mcm was decomposed in ethanol/water mixture at 80 °C to guaifenesin [(RS)-3-(2-methoxyphenoxy)propane-1,2-diol] and carbamate ion [NH2COO-], where the degradation mechanism was explained by trapping the carbamate ion via the complexation with copper(II) ion. The structure of the isolated complex ([Cu(NH2COO)2(H2O)]ṡ4H2O) was elucidated by spectral, thermal, and magnetic tools. Electronic spectra were discussed by TD-DFT and the descriptions of frontier molecular orbitals and the relocations of the electron density were determined. Calculated g-tensor values showed best agreement with experimental values from EPR when carried out using both the B3LYP and B3PW91 functional.

  17. Synthesis and structural characterization of copper(II) complex of 2,2'-bipyridyl and L-lysine

    NASA Astrophysics Data System (ADS)

    Thebo, K. H.; Shad, H. A.; Thebo, A. A.; Raftery, J.

    2014-12-01

    The mixed ligand copper(II) complex of 2,2'-bipyridyl and L-lysine was synthesized from 2,2'-bipyrdine, lysine monohydrochloride and copper perchlorate. The resultant complex was characterized by elemental analysis, X-ray crystallography, IR and thermogravimetric analysis. X-ray studies showed that the title complex is a dimer. The geometry around copper atom is distorted square planar in which the Cu atom is bonded with N and O atoms from L-lysine and N, N atoms of 2,2'-bipyridyl ligand. The crystal structure is orthorhombic with unit cell parameters a = 10.5330(9) Å, b = 13.2169(12) Å, c = 32.618(3) Å; V = 4540.9(7) Å, D x = 8, 1.705 Mg/m3, Mr = 582.83. IR spectral band has been studied and are agreed well with those obtained from the values of the expected CHN analyses and X-ray diffraction. Thermal decomposition of the complex has also been studied under an inert atmosphere.

  18. A novel multi-amplification photoelectrochemical immunoassay based on copper(II) enhanced polythiophene sensitized graphitic carbon nitride nanosheet.

    PubMed

    Li, Rongxia; Liu, Yixin; Li, Xiaojian; Zhang, Sen; Wu, Dan; Zhang, Yong; Wei, Qin; Du, Bin

    2014-12-15

    A new sandwich photoelectrochemical (PEC) sensing strategy was proposed for the first time based on the increasing photocurrent of water-soluble polythiophene sensitized g-C3N4 nanosheet (PT-Cl/g-C3N4) in the presence of copper(II) (Cu(2+)), which was doped on the surface of titanium dioxide as labels for multi-amplification. Herein, the photoactive films of PT-Cl/g-C3N4 is employed as the photoactive antibody (Ab1) immobilization matrix for the subsequent sandwich-type antibody-antigen affinity interactions. Upon the presence of antigen (Ag), greatly enhanced photocurrent could be triggered in the PEC platform by the labels of second antibody (Ab2) of Cu(2+) doped titanium dioxide (Cu(2+)-TiO2). As a result of the multi-amplification in this Cu(2+)-TiO2 enhanced PT-Cl/g-C3N4-based PEC immunoassay, it possesses excellent analytical performance. The antigen could be detected from 0.01 pg mL(-1) to 100.0 ng mL(-1) with a detection limit of 5 fg mL(-1). This work opens up g-C3N4 nanosheet applied in PEC sensing. More importantly, the strategy of specific positive effect of Cu(2+) on the photocurrent of g-C3N4 opens an alternative horizon for PEC sensing. PMID:25037032

  19. Bis(acesulfamato-kappa2N3,O4)bis(2-aminopyrimidine-kappaN1)copper(II).

    PubMed

    Bulut, Ahmet; Içbudak, Hasan; Sezer, Gözde; Kazak, Canan

    2005-05-01

    In the crystal structure of the title compound, bis(2-aminopyrimidine-kappaN1)bis[6-methyl-1,2,3-oxathiazin-4(3H)-one 2,2-dioxide(1-)-kappa2N3,O4]copper(II), [Cu(C4H4NO4S)2(C4H5N3)2], the first mixed-ligand complex of acesulfame, the CuII centre resides on a centre of symmetry and has an octahedral geometry that is distorted both by the presence of four-membered chelate rings and by the Jahn-Teller effect. The equatorial plane is formed by the N atoms of two aminopyrimidine (ampym) ligands and by the weakly basic carbonyl O atoms of the acesulfamate ligands, while the more basic deprotonated N atoms of these ligands are in the elongated axial positions with a strong misdirected valence. The crystal is stabilized by pyrimidine ring stacking and by intermolecular hydrogen bonding involving the NH2 moiety of the ampym ligand and the carbonyl O atom of the acesulfamate moiety. PMID:15876705

  20. Selective adsorption of silver(I) ions over copper(II) ions on a sulfoethyl derivative of chitosan.

    PubMed

    Petrova, Yulia S; Pestov, Alexandr V; Usoltseva, Maria K; Neudachina, Ludmila K

    2015-12-15

    This study presents a simple and effective method of preparation of N-(2-sulfoethyl) chitosan (NSE-chitosan) that allows obtaining a product with a degree of modification up to 1.0. The chemical structure of the obtained polymers was confirmed by FT-IR and 1H NMR spectroscopies. Cross-linking of N-(2-sulfoethyl) chitosans by glutaraldehyde allows preparation of sorbents for removal and concentration of metal ions. Capacity of sorbents towards hydroxide ions was determined depending on the degree of sulfoethylation under static and dynamic conditions. Dissociation constants of functional amino groups of the analyzed sorbents were determined by potentiometric titration. It was shown that basicity of the amino groups decreased (wherein pKa decreased from 6.53 to 5.67) with increase in degree of sulfoethylation. It explains the significant influence of sulfo groups on selectivity of sorption of metal ions on N-(2-sulfoethyl) chitosan-based sorbents. The investigated substances selectively remove copper(II) and silver(I) ions from solutions of complex composition. Wherein the selectivity coefficient KAg/Cu increased to 20 (pH 6.5, ammonium acetate buffer solution) with increase in degree of sulfoethylation of the sorbent up to 1.0. PMID:26282087

  1. Antimicrobial effects of copper(II) bis(thiosemicarbazonato) complexes provide new insight into their biochemical mode of action.

    PubMed

    Djoko, Karrera Y; Paterson, Brett M; Donnelly, Paul S; McEwan, Alastair G

    2014-04-01

    The copper(II) complexes of bis-thiosemicarbazones (Cu(btsc)) such as Cu(atsm) and Cu(gtsm) are neutral, lipophilic compounds that show promise as therapeutics for the treatment of certain neurological diseases and cancers. Although the effects of these compounds have been described at the cellular level, there is almost no information about their biochemical mode of action. In this work, we showed that Cu(atsm) and Cu(gtsm) displayed antimicrobial activities against the human obligate pathogen Neisseria gonorrhoeae that were more than 100 times more potent than Cu(NO3)2 salt alone. Treatment with Cu(btsc) also produced phenotypes that were consistent with copper poisoning, but the levels of intracellular copper were undetectable by ICP MS. We observed that Cu(btsc) interacted with proteins in the cell membrane. Systematic measurements of O2 uptake further demonstrated that treatment with both Cu(atsm) and Cu(gtsm) led to dose-dependent inhibition of respiratory electron transfer processes via succinate and NADH dehydrogenases. These dehydrogenases were not inhibited by a non-btsc source of Cu(II). The results led us to conclude that the biochemical mechanism of Cu(btsc) action is likely more complex than the present, simplistic model of copper release into the cytoplasm. PMID:24435165

  2. Joint toxicity of tetracycline with copper(II) and cadmium(II) to Vibrio fischeri: effect of complexation reaction.

    PubMed

    Tong, Fei; Zhao, Yanping; Gu, Xueyuan; Gu, Cheng; Lee, Charles C C

    2015-03-01

    Co-contamination of antibiotic and heavy metals commonly occurs in the environment. Tetracycline (TC), a common antibiotic, can behave as an efficient organic ligand to complex with cations. In this paper, the joint toxicity of TC with two commonly existing metals, copper(II) and cadmium(II), towards a luminescent bacteria, Vibrio fischeri, are investigated. Results showed that coexistence of TC and Cu(II) showed a significant antagonistic effect, while TC and Cd(II) showed a synergistic effect. The aqueous speciation of TC with two metal cations was calculated using a chemical equilibrium software Visual MINTEQ and results indicated that a strong complexation exist between TC and Cu(II), while much weaker interaction between TC and Cd(II). Traditional joint toxicity prediction model based on independent action failed to predict the combined toxicity of TC with metals. A new method based on speciation calculation was used to evaluate the joint toxicity of ligands and cations. It is assumed that the metal-ligand complexes are non-toxic to V. fischeri and the joint toxicity is determined by the sum of toxic unit of free metal-ions and free organic ligands. It explained the joint toxicity of the mixed systems reasonably well. Meanwhile, citric acid (CA) and fulvic acid (FA) were also introduced in this study to provide a benchmark comparison with TC. Results showed it is also valid for mixed systems of CA and FA with metals except for the Cd-CA mixture. PMID:25398505

  3. Copper(II) complexes as catalyst for the aerobic oxidation of o-phenylenediamine to 2,3-diaminophenazine

    NASA Astrophysics Data System (ADS)

    Khattar, Raghvi; Yadav, Anjana; Mathur, Pavan

    2015-05-01

    Two new mononuclear copper(II) complexes [Cu (L) (NO3)2] (1) and [Cu (L) Br2] (2) where (L = bis(1-(pyridin-2-ylmethyl)-benzimidazol-2-ylmethyl)ether) are synthesized and characterized by single-crystal X-ray diffraction analysis, elemental analysis, UV-Visible, IR spectroscopy, EPR and cyclic voltammetry. The complexes exhibit different coordination structures; the E1/2 value of the complex (1) is found to be relatively more cathodic than that of complex (2). X-band EPR spectra at low temperature in DMF supports a tetragonally distorted complex (1) while complex (2) shows three different g values suggesting a rhombic geometry. These complexes were utilized as a catalyst for the aerobic oxidation of o-phenylenediamine to 2,3-diaminophenazine assisted by molecular oxygen. The initial rate of reaction is dependent on the concentration of Cu(II) complex as well as substrate, and was found to be higher for the nitrate bound complex, while presence of acetate anion acts as a mild inhibitor of the reaction, as it is likely to pick up protons generated during the course of reaction. The inhibition suggests that the generated protons are further required in another important catalytic step.

  4. Synthesis of new oxamide-based ligand and its coordination behavior towards copper(II) ion: spectral and electrochemical studies.

    PubMed

    Krishnapriya, K R; Saravanakumar, D; Arunkumar, P; Kandaswamy, M

    2008-04-01

    A new ligand N,N'-bis{3-(2-formyl-4-methyl-phenol)-6-iminopropyl}oxamide (L) and its mono- and binuclear copper(II) complexes have been synthesized and characterized. The ligand shows absorption maxima at 249 and 360 with a weak transition at 455 nm. The ligand was found to be fluorescent and shows an emission maximum at 516 nm on excitation at 360 nm. The electronic spectra of the mono- and binuclear Cu(II) complexes exhibited a d-d transition in the region 520-560 nm characteristic of square planar geometry around Cu(II) ion. The ESR spectrum of the mononuclear complex showed four lines with nuclear hyperfine splitting. The binuclear complex showed a broad ESR spectrum with g=2.10 due to antiferromagnetic interaction between the two Cu(II) ions. The room-temperature magnetic moment values (micro(eff)) for the mono- and binuclear Cu(II) complexes are found to be 1.70 micro(B) and 1.45 micro(B), respectively. The electrochemical studies of the mononuclear Cu(II) complex showed a single irreversible one-electron wave at -0.70 V (E(pc)) and the binuclear Cu(II) complex showed two irreversible one-electron reduction waves at -0.75 V (E(pc)(1)) and -1.27 V (E(pc)(2)) in the cathodic region. PMID:17690008

  5. Synthesis of new oxamide-based ligand and its coordination behavior towards copper(II) ion: Spectral and electrochemical studies

    NASA Astrophysics Data System (ADS)

    Krishnapriya, K. R.; Saravanakumar, D.; Arunkumar, P.; Kandaswamy, M.

    2008-04-01

    A new ligand N, N'-bis{3-(2-formyl-4-methyl-phenol)-6-iminopropyl}oxamide ( L) and its mono- and binuclear copper(II) complexes have been synthesized and characterized. The ligand shows absorption maxima at 249 and 360 with a weak transition at 455 nm. The ligand was found to be fluorescent and shows an emission maximum at 516 nm on excitation at 360 nm. The electronic spectra of the mono- and binuclear Cu(II) complexes exhibited a d-d transition in the region 520-560 nm characteristic of square planar geometry around Cu(II) ion. The ESR spectrum of the mononuclear complex showed four lines with nuclear hyperfine splitting. The binuclear complex showed a broad ESR spectrum with g = 2.10 due to antiferromagnetic interaction between the two Cu(II) ions. The room-temperature magnetic moment values ( μeff) for the mono- and binuclear Cu(II) complexes are found to be 1.70 μB and 1.45 μB, respectively. The electrochemical studies of the mononuclear Cu(II) complex showed a single irreversible one-electron wave at -0.70 V ( Epc) and the binuclear Cu(II) complex showed two irreversible one-electron reduction waves at -0.75 V ( Epc1) and -1.27 V ( Epc2) in the cathodic region.

  6. Synthesis, structural characterization and in vitro biological screening of some homoleptic copper(II) complexes with substituted guanidines.

    PubMed

    Murtaza, Ghulam; Rauf, Muhammad Khawar; Badshah, Amin; Ebihara, Masahiro; Said, Muhammad; Gielen, Marcel; de Vos, Dick; Dilshad, Erum; Mirza, Bushra

    2012-02-01

    A series of homoleptic copper(II) complexes (1a-8a) with N,N',N″-trisubstituted guanidines, [Cu(II){PhCONHC(NHR)NPh}(2)] (where R = phenyl (1a), n-butyl (2a), sec-butyl (3a), cyclohexyl (4a), 1-naphthyl (5a), 2,4-dichlorophenyl (6a), 3,4-dichlorophenyl (7a), and 3,5-dichlorophenyl (8a)) have been synthesized and characterized by elemental analyses, FT-IR, UV-visible, (1)H and (13)C NMR spectroscopy, and single crystal X-ray diffraction analysis. The X-ray crystal structures revealed that the complexes 2a and 4a are mononuclear in the solid state and that the geometry around the copper atom is nearly square planar. In both the cases, N,N',N″-trisubstituted guanidine ligands have been coordinated to the Cu(II) through the oxygen and nitrogen atoms. The synthesized guanidines and their complexes were initially screened for their anti-microbial activities, and Brine Shrimps Lethality assay. The complexes were also screened for in vitro cytotoxicity activity in human cell lines carcinomas A498, EVSAT, H226, IGROV, M19, MCF-7 and WIDR. The results show a moderate level of cytotoxicity against these seven human cancer cell lines as compared with standard chemotherapeutic drugs. PMID:22177420

  7. Synthesis, structure and electrochemical behavior of a 3D crystalline copper(II) metal-organic framework

    NASA Astrophysics Data System (ADS)

    Bai, Hong-Ye; Fan, Wei-Qiang; Liu, Chun-Bo; Shi, Wei-Dong; Yan, Yong-Sheng

    2014-05-01

    Using an flexible amide-type tripodal ligand N,N‧,N″-tris(3-pyridyl)-1,3,5-benzenetricarboxamide (L) and 1,4-benzenedicarboxylic acid (H2bdc), a three-dimensional copper(II) metal-organic framework (MOF) formulated as [Cu(bdc)(L)]n has been hydrothermally synthesized and structurally characterized by IR, elemental, X-ray single-crystal diffraction and thermal analysis. The complex crystallizes in the triclinic, space group P - 1, a = 8.891(2) Å, b = 11.760(2) Å, c = 15.348(3) Å, α = 96.73(3)°, β = 105.96(3)°, γ = 106.47(3)°, V = 1446.2(5) Å3, Mr = 666.10, Dc = 1.530 g/cm3, Z = 2, F(000) = 682, GOOF = 1.0560, μ(MoKα) = 0.817 mm-1, R = 0.0366 and wR = 0.0885. The structural analyses reveal that the title compound consists of one Cu(II) atom, two halves of bdc, and one L ligand. Each Cu(II) atom is linked by two bdc ligands and three L ligands to form a three-dimensional network. In addition, the electrochemical behavior of title compound has been studied. CCDC No. 990526.

  8. Experimental and theoretical investigation of a novel mononuclear copper(II) azido compound with tridentate (NNO) Schiff base

    NASA Astrophysics Data System (ADS)

    Karahan, Ahmet; Karabulut, Sedat; Dal, Hakan; Kurtaran, Raif; Leszczynski, Jerzy

    2015-08-01

    The tridentate (NNO) Schiff base (HL), has been prepared by the condensation of 2-(aminomethyl)pyridine with 5-chloro-salicylaldehyde. The mononuclear [N-(2-pyridylmethyl)-3-chloro-salicylaldiminato] (azido) copper(II) complex of general formula [Cu(L)(N3)] (1) has been synthesized by the treatment of HL and CuCl2·2H2O with sodium azide. The ligand and complex have been investigated by various methods including IR, TG-DTA and X-ray diffraction techniques. The complex crystallizes in monoclinic space group P21/c, with unit cell dimensions a = 6.7369(4), b = 11.6058(8), c = 17.1379(11) Å, β = 93.823(2)°. The distorted square-planar Cu(II) ion in complex is chelated by one imino N, one phenolic O and one pyridine N atoms of Schiff base ligand and one N atom of azide ion. The electrochemical behavior of the mononuclear copper azido complex was studied with cyclic voltammetry. Tautomer stability of the ligand and the complex has been determined by molecular modeling techniques. It has been concluded that the HL is more stable than its tautomeric form (THL) both as ligand and complex structures.

  9. Copper(II) complexes with 2-pyridineformamide-derived thiosemicarbazones: Spectral studies and toxicity against Artemia salina

    NASA Astrophysics Data System (ADS)

    Ferraz, Karina O.; Wardell, Solange M. S. V.; Wardell, James L.; Louro, Sonia R. W.; Beraldo, Heloisa

    2009-07-01

    The copper(II) complexes [Cu(H2Am4DH)Cl 2] ( 1), [Cu(H2Am4Me)Cl 2] ( 2), [Cu(H2Am4Et)Cl 2] ( 3) and [Cu(2Am4Ph)Cl] ( 4) with 2-pyridineformamide thiosemicarbazone (H2Am4DH) and its N(4)-methyl (H2Am4Me), N(4)-ethyl (H2Am4Et) and N(4)-phenyl (H2Am4Ph) derivatives were studied by means of infrared and EPR spectral techniques. The crystal structure of 4 was determined. The studied compounds proved to be toxic to Artemia salina, suggesting that they could present cytotoxic activity against solid tumors. Among the free thiosemicarbazones H2Am4Ph presented higher toxicity than all other compounds, which showed comparable effects. In the case of complexes 2 and 3 toxicity is probably attributable to the complex as an entity or to a synergistic effect involving the thiosemicarbazone and copper. H2Am4Ph and complexes 2 and 3 revealed to be the most promising compounds as potential antineoplasic agents.

  10. Spectroscopy: The study of DNA cleavage by newly synthesized polydentate macrocyclic ligand and its copper(II) complexes

    NASA Astrophysics Data System (ADS)

    Gupta, Lokesh Kumar; Chandra, Sulekh

    2008-11-01

    A novel hexadentate nitrogen donor [N 6] macrocyclic ligand, i.e. 2,6,12,16,21,22-hexaaza-3,5,13,15-tetramethyl-4,14-diethyl-tricyclo-[15.3.1.1(7-11)]docosane-1(21),2,5,7(22),8,10,12,15,17,19-decaene ( L), has been synthesized. Copper(II) complexes with this ligand have been prepared and subjected to elemental analyses, molar conductance measurements, magnetic susceptibility measurements, mass, 1H NMR (ligand), IR, electronic, and EPR spectral studies. On the basis of molar conductance the complexes may be formulated as [Cu(L)X 2] [X = Cl -, Br -, NO 3- and CH 3COO -] due to their nonelectrolytic nature in N, N'-dimethylformamide (DMF). All the complexes are of the high spin type and are six coordinated. On the basis of IR, electronic and EPR spectral studies tetragonal geometry has been assigned to the Cu(II) complexes. The interaction of these complexes with calf thymus DNA has been explored by using absorption, emission, viscosity measurements, electrochemical studies and DNA cleavage. All the experimental results suggest that the complexes bind to DNA and also promote the cleavage plasmid pBR 322, in the presence of H 2O 2 and ascorbic acid.

  11. Solid phase extraction of copper(II) ions using C18-silica disks modified by oxime ligands.

    PubMed

    Dindar, M Hami; Fathi, S A M; Yaftian, M R; Noushiranzadeh, N

    2010-07-15

    5-Tert-butyl-2-hydroxy-benzaldehyde oxime (L(1)) and 3,5-di-tert-butyl-2-hydroxy-benzaldehyde oxime (L(2)) are synthesized and characterized by conventional spectroscopic methods. These ligands are used as modifier of octadecyl silica membrane disks for separation and pre-concentration of trace amounts of copper(II) ions, followed by sulfuric or nitric acid elution and flame atomic absorption spectrometric (FAAS) determination. The effect of parameters influencing the extraction efficiency i.e. pH of sample solutions, amount of the oxime, type and volume of eluent, sample solution and eluent flow rates were evaluated. Under optimum experimental conditions, the maximum capacity of the membrane disks modified by 6 mg of L(1) or 4 mg of L(2) was found to be 284.7 (+/-2.8) microg of copper and 382.5 (+/-3.1) microg of copper, respectively. The detection limits of the presented methods are 0.29 ng ml(-1) for L(1) and 0.25 ng ml(-1) for L(2). The enrichment factors are greater than 400 for both cases. These methods were successfully applied to the extraction, recovery and detection of copper in different water samples. PMID:20381963

  12. Nickel(II) Complex of Polyhydroxybenzaldehyde N4-Thiosemicarbazone Exhibits Anti-Inflammatory Activity by Inhibiting NF-κB Transactivation

    PubMed Central

    Loh, Sheng Wei; Looi, Chung Yeng; Hassandarvish, Pouya; Phan, Alicia Yi Ling; Wong, Won Fen; Wang, Hao; Paterson, Ian C.; Ea, Chee Kwee; Mustafa, Mohd Rais; Maah, Mohd Jamil

    2014-01-01

    Background The biological properties of thiosemicarbazone have been widely reported. The incorporation of some transition metals such as Fe, Ni and Cu to thiosemicarbazone complexes is known to enhance its biological effects. In this study, we incorporated nickel(II) ions into thiosemicarbazone with N4-substitution groups H3L (H; H3L1, CH3; H3L2, C6H5; H3L3 and C2H5; H3L4) and examined its potential anti-inflammatory activity. Methodology/Principal Findings Four ligands (1–4) and their respective nickel-containing complexes (5–8) were synthesized and characterized. The compounds synthesized were tested for their effects on NF-κB nuclear translocation, pro-inflammatory cytokines secretion and NF-κB transactivation activity. The active compound was further evaluated on its ability to suppress carrageenan-induced acute inflammation in vivo. A potential binding target of the active compound was also predicted by molecular docking analysis. Conclusions/Significance Among all synthesized compounds tested, we found that complex [Ni(H2L1)(PPh3)]Cl (5) (complex 5), potently inhibited IκBα degradation and NF-κB p65 nuclear translocation in LPS-stimulated RAW264.7 cells as well as TNFα-stimulated HeLa S3 cells. In addition, complex 5 significantly down-regulated LPS- or TNFα-induced transcription of NF-κB target genes, including genes that encode the pro-inflammatory cytokines TNFα, IFNβ and IL6. Luciferase reporter assays confirmed that complex 5 inhibited the transactivation activity of NF-κB. Furthermore, the anti-inflammatory effect of complex 5 was also supported by its suppressive effect on carrageenan-induced paw edema formation in wild type C57BL/6 mice. Interestingly, molecular docking study showed that complex 5 potentially interact with the active site of IKKβ. Taken together, we suggest complex 5 as a novel NF-κB inhibitor with potent anti-inflammatory effects. PMID:24977407

  13. Synthesis, characterization, and antimicrobial activity of silver(I) and copper(II) complexes of phosphate derivatives of pyridine and benzimidazole.

    PubMed

    Kalinowska-Lis, Urszula; Szewczyk, Eligia M; Chęcińska, Lilianna; Wojciechowski, Jakub M; Wolf, Wojciech M; Ochocki, Justyn

    2014-01-01

    Two silver(I) complexes--[Ag(4-pmOpe)]NO₃}(n) and [Ag(2-bimOpe)₂]NO₃--and three copper(II) complexes--[Cu₄Cl₆O(2-bimOpe)₄], [CuCl₂(4-pmOpe)₂], and [CuCl₂(2-bis(pm)Ope]--were synthesized by reaction of silver(I) nitrate or copper(II) chloride with phosphate derivatives of pyridine and benzimidazole, namely diethyl (pyridin-4-ylmethyl)phosphate (4-pmOpe), 1H-benzimidazol-2-ylmethyl diethyl phosphate (2-bimOpe), and ethyl bis(pyridin-2-ylmethyl)phosphate (2-bis(pm)Ope). These compounds were characterized by ¹H, ¹³C, and ³¹P NMR as well as IR spectroscopy, elemental analysis, and ESIMS spectrometry. Additionally, molecular and crystal structures of {[Ag(4-pmOpe)]NO₃}n and [Cu₄Cl₆O(2-bimOpe)₄] were determined by single-crystal X-ray diffraction analysis. The antimicrobial profiles of synthesized complexes and free ligands against test organisms from the ATCC and clinical sources were determined. Silver(I) complexes showed good antimicrobial activities against Candida albicans strains (MIC values of ∼19 μM). [Ag(2-bimOpe)₂]NO₃ was particularly active against Pseudomonas aeruginosa and methicillin-resistant Staphylococcus epidermidis, with MIC values of ∼5 and ∼10 μM, respectively. Neither copper(II) complexes nor the free ligands inhibited the growth of test organisms at concentrations below 500 μg mL⁻¹. PMID:24218046

  14. Comparative analysis of the cytotoxicity of substituted [phenylglyoxal bis(4-methyl-3-thiosemicarbazone)] copper(II) chelates. 2. Parabolic correlations and their implications for selective toxicity.

    PubMed

    Coats, E A; Milstein, S R; Pleiss, M A; Roesener, J A

    1978-08-01

    The synthesis of an extended series of para-substituted [phenylglyoxal bis(4-methyl-3-thiosemicarbazone)] copper(II) chelates is reported. Subsequent biological evaluation and regression analysis have been performed, correlating pI50 with extrathermodynamic substituent parameters. Parabolic correlations with pi have resulted which predict optimum lipophilic character of the para substituent with respect to Ehrlich ascites cytotoxicity (pi0 = -2.13) and with respect to ascites vs. liver slice cytotoxicity (pi0 = -1.31). Results indicated clearly that the chelate most toxic to the tumor cell model may not be the most selective. PMID:691005

  15. Syntheses, crystal structures, spectral study and DFT calculation of three new copper(II) complexes derived from pyridoxal hydrochloride, N,N-dimethylethylenediamine and N,N-diethylethylenediamine

    NASA Astrophysics Data System (ADS)

    Mandal, Senjuti; Naskar, Barnali; Modak, Ritwik; Sikdar, Yeasin; Chatterjee, Sudipta; Biswas, Sujan; Mondal, Tapan Kumar; Modak, Debadrita; Goswami, Sanchita

    2015-05-01

    Two pyridoxal containing Schiff bases obtained by condensation of pyridoxal hydrochloride with N,N-dimethylethylenediamine (HL1) and N,N-diethylethylenediamine (HL2) are used for the syntheses of three new copper (II) complexes [Cu(HL1)(H2O)Cl]Cl (1), [Cu(L1)Cl] (2) and [Cu(L2)Cl] (3). The single crystal X-ray structures of all the three copper(II) complexes are determined. Redox potentials for the mononuclear complexes are measured by cyclic voltammetry experiments. The DFT and TDDFT results have been used to interpret the experimental properties.

  16. Crystal structure of a binuclear nickel(II) complex constructed of 1H-imidazo[4,5-f][1,10]phenanthroline and doubly deprotonated benzene-1,3,5-tri­carb­oxy­lic acid

    PubMed Central

    Lv, Ying; Hao, Xiang-Rong

    2015-01-01

    The title complex, [Ni2(C9H4O6)2(C13H8N4)2(H2O)4]·2H2O, bis­(μ-5-carb­oxy­benzene-1,3-di­carboxyl­ato-κ2 O 1:O 1′)bis­[di­aqua(1H-imidazo[4,5-f][1,10]phenanthroline-κ2 N 7,N 8)nickel(II)] di­hydrate, was obtained under solvothermal conditions by the reaction of benzene-1,3,5-tricarboxylic acid (H3BTC) with Ni(NO3)2 in the presence of 1H-imidazo[4,5-f][1,10]phenanthroline (IP). The crystal has triclinic (P-1) symmetry with a centrosymmetric binuclear nickel(II) cluster. The NiII atom is coordinated by two N atoms from a chelating 1H-imidazo[4,5-f][1,10]phenanthroline ligand, two carboxyl­ate O atoms from two 5-carb­oxy­benzene-1,3-di­carboxyl­ate ligands and two water mol­ecules in a slightly distorted octa­hedral geometry. Two carboxyl­ate groups bridge two NiII cations, forming the binuclear complex. Extensive N—H⋯O, O—H⋯O and O—H⋯N hydrogen bonding is present in the crystal structure, forming a three-dimensional supermolecular framework. Weak π–π stacking is observed between parallel HBTC2− and IP ring systems, the face-to-face separation being 3.695 (2) Å. PMID:26029419

  17. Synthesis, structures and Helicobacter pylori urease inhibitory activity of copper(II) complexes with tridentate aroylhydrazone ligands.

    PubMed

    Pan, Lin; Wang, Cunfang; Yan, Kai; Zhao, Kedong; Sheng, Guihua; Zhu, Hailiang; Zhao, Xinlu; Qu, Dan; Niu, Fang; You, Zhonglu

    2016-06-01

    A series of new copper(II) complexes were prepared. They are [CuL(1)(NCS)] (1), [CuClL(1)]·CH3OH (2), [CuClL(2)]·CH3OH (3), [CuL(3)(NCS)]·CH3OH (4), [CuL(4)(NCS)]·0.4H2O (5), and [CuL(5)(bipy)] (6), where L(1), L(2), L(3) and L(4) are the deprotonated form of N'-(2-hydroxybenzylidene)-3-methylbenzohydrazide, 4-bromo-N'-(2-hydroxy-5-methoxybenzylidene)benzohydrazide, N'-(2-hydroxy-5-methoxybenzylidene)-3-methylbenzohydrazide and 2-chloro-N'-(2-hydroxy-5-methoxybenzylidene)benzohydrazide, respectively, L(5) is the dianionic form of N'-(2-hydroxybenzylidene)-3-methylbenzohydrazide, and bipy is 2,2'-bipyridine. The complexes were characterized by infrared and UV-Vis spectra and single crystal X-ray diffraction. The Cu atoms in complexes 1, 2, 3, 4 and 5 are coordinated by the NOO donor set of the aroylhydrazone ligands, and one Cl or thiocyanate N atom, forming square planar coordination. The Cu atom in complex 6 is in a square pyramidal coordination, with the NOO donor set of L(1), and one N atom of bipy defining the basal plane, and with the other N atom of bipy occupying the apical position. Complexes 1, 2, 3, 4 and 5 show effective urease inhibitory activities, with IC50 values of 5.14, 0.20, 4.06, 5.52 and 0.26μM, respectively. Complex 6 has very weak activity against urease, with IC50 value over 100μM. Molecular docking study of the complexes with the Helicobacter pylori urease was performed. The relationship between structures and urease inhibitory activities indicated that copper complexes with square planar coordination are better models for urease inhibition. PMID:26908284

  18. Anti-thyroid and antifungal activities, BSA interaction and acid phosphatase inhibition of methimazole copper(II) complexes.

    PubMed

    Urquiza, Nora M; Islas, María S; Ariza, Santiago T; Jori, Nadir; Martínez Medina, Juan J; Lavecchia, Martín J; López Tévez, Leonor L; Lezama, Luis; Rojo, Teófilo; Williams, Patricia A M; Ferrer, Evelina G

    2015-03-01

    It has been reported that various metal coordination compounds have improved some biological properties. A high activity of acid phosphatase (AcP) is associated to several diseases (osteoporosis, Alzheimer's, prostate cancer, among others) and makes it a target for the development of new potential inhibitors. Anti-thyroid agents have disadvantageous side effects and the scarcity of medicines in this area motivated many researchers to synthesize new ones. Several copper(II) complexes have shown antifungal activities. In this work we presented for a first time the inhibition of AcP and the anti-thyroid activity produced by methimazole-Cu(II) complexes. Cu-Met ([Cu(MeimzH)2(H2O)2](NO3)2·H2O) produces a weak inhibition action while Cu-Met-phen ([Cu(MeimzH)2(phen)(H2O)2]Cl2) shows a strong inhibition effect (IC50 = 300 μM) being more effective than the reported behavior of vanadium complexes. Cu-Met-phen also presented a fairly good anti-thyroid activity with a formation constant value, Kc=1.02 × 10(10)M(-1) being 10(6) times more active than methimazole (Kc = 4.16 × 10(4)M(-1)) in opposition to Cu-Met which presented activity (Kc=9.54 × 10(3)M(-1)) but in a lesser extent than that of the free ligand. None of the complexes show antifungal activity except Cu-phen (MIC = 11.71 μgmL(-1) on Candidaalbicans) which was tested for comparison. Besides, albumin interaction experiments denoted high affinity toward the complexes and the calculated binding constants indicate reversible binding to the protein. PMID:25641192

  19. Synthesis, spectroscopic characterization, crystallographic studies and antibacterial assays of new copper(II) complexes with sulfathiazole and nimesulide

    NASA Astrophysics Data System (ADS)

    Nunes, Julia Helena Bormio; de Paiva, Raphael Enoque Ferraz; Cuin, Alexandre; da Costa Ferreira, Ana Maria; Lustri, Wilton Rogério; Corbi, Pedro Paulo

    2016-05-01

    New ternary copper(II) complexes of sulfathiazole (SFT, C9H8N3O2S2) or nimesulide (NMS, C13H11N2O5S) and 2,2‧-bipyridine (bipy) were synthesized, and characterized by chemical and spectroscopic techniques. Elemental analyses indicated a 2:1:1 sulfonamide/copper/bipy composition for both complexes. Mass spectrometric measurements permitted identifying the molecular ions [Cu(SFT)2(bipy)+H]+ and [Cu(NMS)2(bipy)+H]+ at m/z 728 and 835, respectively, confirming the proposed compositions. Crystal structure of the [Cu(SFT)2(bipy)] complex was solved by powder X-ray diffraction analysis (PXRD), attesting that the Cu(II) ion is hexacoordinated in a distorted octahedral geometry. Each SFT molecule coordinates to the metal ion by the nitrogen atoms of the SO2-N group and of the heterocyclic ring. The coordination sphere is completed by a bipyridine. Electronic paramagnetic resonance (EPR) studies were carried out for the [Cu(NMS)2(bipy)] complex, indicating a tetragonal environment around the metal ion. It was suggested that NMS coordinates to Cu(II) by the nitrogen and oxygen atoms of the SO2-N group, which was confirmed by infrared spectroscopic studies. Biological studies showed the antibacterial activity of both Cu-SFT and Cu-NMS complexes, with the minimum inhibitory concentration (MIC) values ranging from 0.10 to 0.84 mmol L-1 against Gram-negative bacteria for [Cu(SFT)2(bipy)], and from 1.50 to 3.00 mmol L-1 against Gram-positive and -negative bacteria for [Cu(NMS)2(bipy)].

  20. Halochromism, ionochromism, solvatochromism and density functional study of a synthesized copper(II) complex containing hemilabile amide derivative ligand

    NASA Astrophysics Data System (ADS)

    Golchoubian, Hamid; Moayyedi, Golasa; Reisi, Neda

    2015-03-01

    This study investigates chromotropism of newly synthesized 3,3‧-(ethane-1,2-diylbis(benzylazanediyl))dipropanamide copper(II) perchlorate complex. The compound was structurally characterized by physico-chemical and spectroscopic methods. X-ray crystallography of the complex showed that the copper atom achieved a distorted square pyramidal environment through coordination of two amine N atoms and two O atoms of the amide moieties. The pH effect on the visible absorption spectrum of the complex was studied which functions as pH-induced "off-on-off" switches through protonation and deprotonation of amide moieties along with the Cusbnd O to Cusbnd N bond rearrangement at room temperature. The complex was also observed to show solvatochromism and ionochromism. The distinct solution color changes mainly associated with hemilability of the amide groups. The solvatochromism of the complex was investigated with different solvent parameter models using stepwise multiple linear regression method. The results suggested that the basicity power of the solvent has a dominant contribution to the shift of the d-d absorption band of the complex. Density functional theory, DFT calculations were performed in order to study the electronic structure of the complex, the relative stabilities of the Cusbnd N/Cusbnd O isomers, and to understand the nature of the halochromism processes taking place. DFT computational results buttressed the experimental observations indicating that in the natural pH (5.8) the Cusbnd O isomer is more stable than its linkage isomer and conversely in alkaline aqueous solution.

  1. The thioxotriazole copper(II) complex A0 induces endoplasmic reticulum stress and paraptotic death in human cancer cells.

    PubMed

    Tardito, Saverio; Isella, Claudio; Medico, Enzo; Marchiò, Luciano; Bevilacqua, Elena; Hatzoglou, Maria; Bussolati, Ovidio; Franchi-Gazzola, Renata

    2009-09-01

    The copper(II) complex A0 induces a type of non-apoptotic cell death also known as paraptosis. Paraptosis involves extensive endoplasmic reticulum vacuolization in the absence of caspase activation. A wide panel of human cancer cell lines was used to demonstrate differences in cytotoxicity by the paraptosis-inducing drug A0 and the metal-based pro-apoptotic drug cisplatin. Gene expression profiling of the human fibrosarcoma HT1080 cells showed that, while cisplatin induced p53 targets, A0 up-regulated genes involved in the unfolded protein response (UPR) and response to heavy metals. The cytotoxic effects of A0 were associated with inhibition of the ubiquitin-proteasome system and accumulation of ubiquitinylated proteins, in a manner dependent on protein synthesis. Cycloheximide inhibited the accumulation of ubiquitinylated proteins and hampered A0-induced cell death process. The occurrence of the UPR during A0-induced death process was shown by the increased abundance of spliced XBP1 mRNA, transient eIF2alpha phosphorylation, and a series of downstream events, including attenuation of global protein synthesis and increased expression of ATF4, CHOP, BIP, and GADD34. Mouse embryonic fibroblasts expressing a mutant eIF2alpha, which could not be phosphorylated, were more resistant to A0 than wild type cells, pointing to a pro-death role of eIF2alpha phosphorylation. A0 may thus represent the prototypical member of a new class of compounds that cause paraptotic cell death via mechanisms involving eIF2alpha phosphorylation and the UPR. PMID:19561079

  2. Electrochemical assay for the determination of nitric oxide metabolites using copper(II) chlorophyllin modified screen printed electrodes.

    PubMed

    Balamurugan, Murugesan; Madasamy, Thangamuthu; Pandiaraj, Manickam; Bhargava, Kalpana; Sethy, Niroj Kumar; Karunakaran, Chandran

    2015-06-01

    This work presents a novel electrochemical assay for the collective measurement of nitric oxide (NO) and its metabolites nitrite (NO2(-)) and nitrate (NO3(-)) in volume miniaturized sample at low cost using copper(II) chlorophyllin (CuCP) modified sensor electrode. Zinc oxide (ZnO) incorporated screen printed carbon electrode (SPCE) was used as a host matrix for the immobilization of CuCP. The morphological changes of the ZnO and CuCP modified electrodes were investigated using scanning electron microscopy. The electrochemical characterization of CuCP-ZnO-SPCE exhibited the characteristic quasi-reversible redox peaks at the potential +0.06 V versus Ag/AgCl. This biosensor electrode showed a wide linear range of response over NO concentrations from 200 nM to 500 μM with a detection limit of 100 nM and sensitivity of 85.4 nA μM(-1). Furthermore, NO2(-) measurement showed linearity of 100 nM to 1mM with a detection limit of 100 nM for NO2(-) and sensitivity of 96.4 nA μM(-1). Then, the concentration of NO3(-) was measured after its enzymatic conversion into NO2(-). Using this assay, the concentrations of NO, NO2(-), and NO3(-) present in human plasma samples before and after beetroot supplement were estimated using suitable membrane coated CuCP-ZnO-SPCE and validated with the standard Griess method. PMID:25700865

  3. In vitro cytotoxicity, DNA cleavage and SOD-mimic activity of copper(II) mixed-ligand quinolinonato complexes.

    PubMed

    Buchtík, Roman; Trávníček, Zdeněk; Vančo, Ján

    2012-11-01

    Six mixed-ligand copper(II) complexes with the composition [Cu(qui)(L)]BF(4)·xH(2)O (1-6), where Hqui=2-phenyl-3-hydroxy-4(1H)-quinolinone, L=2,2'-bipyridine (bpy) (1), 1,10-phenanthroline (phen) (2), bis(2-pyridyl)amine (ambpy) (3), 5-methyl-1,10-phenanthroline (mphen) (4), 5-nitro-1,10-phenanthroline (nphen) (5) and bathophenanthroline (bphen) (6), were prepared, fully characterized and studied for their in vitro cytotoxicity on human osteosarcoma (HOS) and human breast adenocarcinoma (MCF7) cancer cell lines. The overall promising results of the cytotoxicity were found for all the complexes, while the best results were achieved for complex 6, with IC(50)=2.6 ± 0.8 μM (HOS), and 1.3 ± 0.5 μM (MCF7). The interactions of the Cu(II) complexes 1-6 with calf thymus DNA were investigated by the UV-visible spectral titration. An agarose-gel electrophoretic method of oxidative damage determination to circular plasmid pUC19 was used to assess the ability of the complexes to act as chemical nucleases. A high effectiveness of DNA cleavage was observed for 2, 4 and 5. In vitro antioxidative activity of the complexes was studied by the superoxide dismutase-mimic (SOD-mimic) method. The best result was afforded by complex 1 with IC(50)=4.7 ± 1.0 μM, which corresponds to 10.2% of the native Cu,Zn-SOD enzyme activity. The ability of the tested complexes to interact with sulfur-containing biomolecules (cysteine and reduced glutathione) at physiological levels was proved by electrospray-ionization mass spectrometry (ESI-MS). PMID:23022693

  4. Extended X-ray absorption fine structure study of mixed-ligand copper(II) complexes having analogous structures

    NASA Astrophysics Data System (ADS)

    Gaur, Abhijeet; Shrivastava, B. D.; Srivastava, Krishna; Prasad, J.

    2013-02-01

    X-ray absorption fine structure spectra have been studied at the Cu K-edge in five mixed-ligand copper(II) complexes, viz., [Cu(L-glu)(bipy)] 1, [Cu(L-glu)(phen) (H2O)].3H2O 2, [Cu(L-tyro)(bipy)(ClO4)].2H2O 3, [Cu(L-phen)(bipy)(H2O)] (ClO4) 4, and [Cu(L-tyro)(phen)(H2O)] (ClO4).1.5H2O 5 (where L-glu = L-glutamate dianion, L-tyro = L-tyrosinate anion, bipy = 2,2'-bipyridine, and phen =1,10-phenanthroline), having essentially the same structure. The crystallographic data are available for all the complexes using which five theoretical models have been generated. Firstly, extended X-ray absorption fine structure (EXAFS) data of each complex has been analyzed using its own theoretical model and the results obtained are found to be comparable with the crystallographic results. Then, the EXAFS data of each complex has been analyzed using the theoretical models of the remaining four of these complexes. For each complex, the structural parameters obtained by fitting EXAFS data with theoretical models of the four remaining complexes have been found to be comparable with those obtained by fitting its own theoretical model. Thus, it has been found that if the crystal structure is not available for a complex, then the crystal structure of similar or analogous complex can be used satisfactorily for generating the theoretical model for the EXAFS data analysis of that complex, even if different ligands are attached to the central metal atom. On the basis of EXAFS data analysis, the coordination geometries around the central metal ions in these complexes have been depicted.

  5. Investigation and Control of "Sphere-Like" Buckminsterfullerene C60 and "Disk-Like" Copper(II) Phthalocyanine

    NASA Astrophysics Data System (ADS)

    McAfee, Terry Richard

    Due to the growing global need for cheap, flexible, and portable electronics, numerous research groups from mechanical and electrical engineering, material science, chemistry, and physics have increasingly turned to organic electronics research over the last ˜5--10 years. Largely, the focus of researchers in this growing field have sought to obtain the next record holding device, allowing a heuristic approach of trial and error to become dominant focus of research rather than a fundamental understanding. Rather than working with the latest high performance organic semiconducting materials and film processing techniques, I have chosen to investigate and control the fundamental self-assembly interactions of organic photovoltaic thin films using simplified systems. Specifically, I focus on organic photovoltaic research using two of the oldest and well studies semiconducting materials, namely "sphere-like" electron donor material Buckminsterfullerene C60 and "disklike" electron acceptor material Copper(II) Phthalocyanine. I manufactured samples using the well-known technique of physical vapor deposition using a high vacuum chamber that I designed and built to accommodate my need of precise material deposition control, with codeposition capability. Films were characterized using microscopy and spectroscopy techniques locally at NCSU, including Atomic Force Microscopy, scanning tunneling microscopy, X-ray photoelectron spectroscopy, and Ultraviolet-visible spectroscopy, as well as at National Laboratory based synchrotron x-ray techniques, including Carbon and Nitrogen k-edge Total Electron Yield and Transmission Near Edge X-ray absorption fine structure spectroscopy, Carbon k-edge Resonant Soft x-ray Microscopy, Resonant Soft x-ray reflectivity, and Grazing Incidence Wide-Angle X-ray scattering.

  6. Examination of the Impact of Copper(II) α-(N)-Heterocyclic Thiosemicarbazone Complexes on DNA Topoisomerase IIα.

    PubMed

    Wilson, James T; Jiang, Xiaohua; McGill, Bradley C; Lisic, Edward C; Deweese, Joseph E

    2016-04-18

    Type II DNA topoisomerases resolve topological knots and tangles in DNA that result from routine cellular processes and are effective targets for anticancer therapeutics. To this end, thiosemicarbazones have been identified as having the ability to kill cancer cells from several cell lines. Literature evidence suggests that at least some thiosemicarbazones have an impact on topoisomerase II activity. However, the mechanism is not as clearly defined. Therefore, we set out to analyze the activity of four α-(N)-heterocyclic thiosemicarbazone compounds against topoisomerase IIα. The ligands, acetylpyridine-ethylthiosemicarbazone (APY-ETSC) and acetylpyrazine-methylthiosemicarbazone (APZ-MTSC), and their copper(II) [Cu(II)] complexes [Cu(APY-ETSC)Cl] and [Cu(APZ-MTSC)Cl] were examined for the ability to impact the catalytic cycle of human topoisomerase IIα. Both [Cu(APY-ETSC)Cl] and [Cu(APZ-MTSC)Cl] were more effective at inhibiting DNA relaxation compared with the ligands alone. Further, both [Cu(APY-ETSC)Cl] and [Cu(APZ-MTSC)Cl] increased double-stranded DNA cleavage levels without inhibiting topoisomerase IIα-mediated DNA ligation. The Cu(II) complexes inactivate enzyme activity over time suggesting a critical interaction with the enzyme. Additionally, we found that the Cu(II)-thiosemicarbazone complexes do not significantly impact DNA cleavage by the catalytic core of the enzyme. This evidence is supported by the fact that both [Cu(APY-ETSC)Cl] and [Cu(APZ-MTSC)Cl], and to a lesser extent the ligands, inhibit topoisomerase IIα-mediated ATP hydrolysis. Based upon kinetic analysis, the Cu(II) complexes appear to be noncompetitive inhibitors of the ATPase domain of topoisomerase IIα. Taken together, our results provide evidence that Cu(II) complexes of α-(N)-heterocyclic thiosemicarbazones catalytically inhibit the enzyme through the ATPase domain but also promote double-stranded DNA cleavage by the enzyme. PMID:26982206

  7. DNA binding, cytotoxicity and apoptosis induction activity of a mixed-ligand copper(II) complex with taurine Schiff base and imidazole

    NASA Astrophysics Data System (ADS)

    Li, Mei; kong, Lin Lin; Gou, Yi; Yang, Feng; Liang, Hong

    2014-07-01

    A novel binuclear copper(II) complex (complex 1) with taurine Schiff base and imidazole has been synthesized and structurally characterized by single crystal X-ray diffraction, elemental analysis, ESI-MS spectrometry, UV-vis and IR spectroscopy. Single-crystal analysis revealed that 1 displays the sulfonate-bridged dinuclear copper(II) centers. Both copper atoms are five-coordinated and exhibit slightly distorted square pyramidal geometries. Each of copper atom is surrounded by three oxygen atoms and one nitrogen atom from different taurine Schiff base ligands, and one nitrogen atom from one imidazole ligand. The interaction between 1 and calf thymus DNA (CT-DNA) was investigated by UV-vis, fluorescence, circular dichroism (CD) spectra and agarose gel electrophoresis. The experimental results indicated that 1 could bind to CT-DNA via an intercalative mode and show efficient cleavage activity. In addition, 1 showed an antitumor effect on cell cycle and apoptosis. Flow cytometric analysis revealed that MGC-803 cells were arrested in the S phase after treatment with 1. Fluorescence microscopic observation indicated that 1 could induce apoptosis of MGC-803 cells.

  8. Structural studies of copper(II) complexes with 2-(2-aminoethyl)pyridine derived Schiff bases and application as precursors of thin organic-inorganic layers.

    PubMed

    Barwiolek, Magdalena; Szlyk, Edward; Berg, Andrzej; Wojtczak, Andrzej; Muziol, Tadeusz; Jezierska, Julia

    2014-07-14

    Cu(ii) complexes with Schiff bases derived from 2-pyridin-2-ylethanamine were obtained and characterized by UV-Vis, fluorescence, and IR spectra. The X-ray crystal structures determined for [Cu(ii)(epy(di-t-Buba))Cl] × 0.042H2O and [Cu(ii)(epy(di-t-Buba))O2CCH3] revealed tetrahedral distortion of the Cu(ii) coordination sphere in the solid phase. For both molecules the Cu(ii) ions were found in tetragonal environments, as was confirmed by the values of EPR g-matrix diagonal components. The thermal properties of the complexes and the gas phase composition were studied by TG/IR techniques. Thin layers of the studied copper(ii) complexes were deposited on Si(111) by a spin coating method and characterized by scanning electron microscopy (SEM/EDS), atomic force microscopy (AFM) and fluorescence spectra. For copper(ii) layers the most intensive fluorescence band from intra-ligand transition was observed between 498 and 588 nm. The layers' fluorescence intensity was related to the rotation speed and deposition time. PMID:24848427

  9. Synthesis and Characterisation of Copper(II) Complexes with Tridentate NNO Functionalized Ligand: Density Function Theory Study, DNA Binding Mechanism, Optical Properties, and Biological Application

    PubMed Central

    Hazra, Madhumita; Dolai, Tanushree; Pandey, Akhil; Dey, Subrata Kumar; Patra, Animesh

    2014-01-01

    The photo physical properties of two mononuclear pentacoordinated copper(II) complexes formulated as [Cu(L)(Cl)(H2O)] (1) and [Cu(L)(Br)(H2O)] (2) HL = (1-[(3-methyl-pyridine-2-ylimino)-methyl]-naphthalen-2-ol) were synthesized and characterized by elemental, physicochemical, and spectroscopic methods. The density function theory calculations are used to investigate the electronic structures and the electronic properties of ligand and complex. The interactions of copper(II) complexes towards calf thymus DNA were examined with the help of absorption, viscosity, and fluorescence spectroscopic techniques at pH 7.40. All spectroscopy's result indicates that complexes show good binding activity to calf thymus DNA through groove binding. The optical absorption and fluorescence emission properties of microwires were characterized by fluorescence microscope. From a spectroscopic viewpoint, all compounds strongly emit green light in the solid state. The microscopy investigation suggested that microwires exhibited optical waveguide behaviour which are applicable as fluorescent nanomaterials and can be used as building blocks for miniaturized photonic devices. Antibacterial study reveals that complexes are better antimicrobial agents than free Schiff base due to bacterial cell penetration by chelation. Moreover, the antioxidant study of the ligand and complexes is evaluated by using 1,1-diphenyl-2-picrylhydrazyl (DPPH) free-radical assays, which demonstrate that the complexes are of higher antioxidant activity than free ligand. PMID:25386109

  10. Light-induced copper(II) coordination by a bicyclic tetraaza chelator through a ligand-to-metal charge-transfer reaction.

    PubMed

    Holm-Jørgensen, Jacob R; Jensen, Mikael; Bjerrum, Morten J

    2011-12-19

    To enable utilization of the broad potential of copper isotopes in nuclear medicine, rapid and robust chelation of the copper is required. Bowl adamanzanes (bicyclic tetraaza ligands) can form kinetically stable copper complexes, but they are usually formed at low rates unless high pH values and high temperatures are applied. We have investigated the effects of the variation in the pH, different anions, and UV irradiation on the chelation rate. UV spectra of mixtures of Cu(2+) and [2(4).3(1)]adz in water show the existence of a long-lived two-coordinated copper(II) intermediate (only counting coordinated amine groups) at pH above 6. These findings are supported by pH titrations of mixtures of Cu(2+) and [2(4).3(1)]adz in water. Irradiation of this complex in the ligand-to-metal charge-transfer (LMCT) band by a diode-array spectrophotometer leads to photodeprotonation and subsequently to formation of the four-coordinated copper(II) complex at a rate up to 7800-fold higher at 25 °C than in the dark. Anions in the solution were found to have three major effects: competitive inhibition due to Cu(II) binding anions, inhibition of the photoinduced transchelation from UV-absorbing anions, and photoredox inhibition from acido ligands capable of acting as electron donors in LMCT reactions. Dissolved O(2) was also found to result in photoredox inhibition. PMID:22074363

  11. Mono- and binuclear copper(II) complexes of new hydrazone ligands derived from 4,6-diacetylresorcinol: Synthesis, spectral studies and antimicrobial activity

    NASA Astrophysics Data System (ADS)

    Shebl, Magdy; El-ghamry, Mosad A.; Khalil, Saied M. E.; Kishk, Mona A. A.

    Two new hydrazone ligands, H2L1 and H2L2, were synthesized by the condensation of 4,6-diacetylresorcinol with 3-hydrazino-5,6-diphenyl-1,2,4-triazine and isatin monohydrazone, respectively. The structures of the ligands were elucidated by elemental analyses, IR, 1H NMR, electronic and mass spectra. Reactions of the ligands with several copper(II) salts, including AcO-, NO3-, SO42-, Cl- and Br- afforded mono- and binuclear metal complexes. Also, the ligands were allowed to react with Cu(II) ion in the presence of a secondary ligand (L‧) [N,O-donor; 8-hydroxyquinoline, N,N-donor; 1,10-phenanthroline or O,O-donor; benzoylacetone]. Characterization and structure elucidation of the prepared complexes were achieved by elemental and thermal analyses, IR, electronic, mass and ESR spectra as well as conductivity and magnetic susceptibility measurements. The ESR spin Hamiltonian parameters of some complexes were calculated. The spectroscopic data showed that the H2L1 ligand acts as a neutral or monobasic tridentate ligand while the H2L2 ligand acts as a bis(monobasic tridentate) ligand. The coordination sites with the copper(II) ion are phenolic oxygen, azomethine nitrogen and triazinic nitrogen (H2L1 ligand) or isatinic oxygen (H2L2 ligand). The metal complexes exhibited octahedral and square planar geometrical arrangements depending on the nature of the anion. The ligands and some metal complexes showed antimicrobial activity.

  12. Role of the Copper(II) Complex Cu[15]pyN5 in Intracellular ROS and Breast Cancer Cell Motility and Invasion.

    PubMed

    Fernandes, Ana S; Flórido, Ana; Saraiva, Nuno; Cerqueira, Sara; Ramalhete, Sérgio; Cipriano, Madalena; Cabral, Maria Fátima; Miranda, Joana P; Castro, Matilde; Costa, Judite; Oliveira, Nuno G

    2015-10-01

    Multiple mechanisms related to metastases undergo redox regulation. Cu[15]pyN5 is a redox-active copper(II) complex previously studied as a chemotherapy sensitizer in mammary cells. The effects of a cotreatment with Cu[15]pyN5 and doxorubicin (dox) were evaluated in two human breast cancer cell lines: MCF7 (low aggressiveness) and MDA-MB-231 (highly aggressive). Cu[15]pyN5 decreased MCF7-directed cell migration. In addition, a cotreatment with dox and Cu[15]pyN5 reduced the proteolytic invasion of MDA-MB-231 cells. Cell detachment was not affected by exposure to these agents. Cu[15]pyN5 and dox significantly increased intracellular ROS in both cell lines. This increase could be at least partially due to H2 O2 accumulation. The combination of Cu[15]pyN5 with dox may be beneficial in breast cancer treatment as it could help reduce cancer cell migration and invasion. Moreover, the ligand [15]pyN5 has a high affinity for copper(II) and displays potential anti-angiogenic properties. Overall, we present a potential drug that might arrest the progression of breast cancer by different and complementary mechanisms. PMID:25600158

  13. Spectral and structural studies of copper(II) complexes of thiosemicarbazones derived from salicylaldehyde and containing ring incorporated at N(4)-position

    NASA Astrophysics Data System (ADS)

    Latheef, Leji; Kurup, Maliyeckal R. Prathapachandra

    2008-06-01

    Mononuclear and binuclear copper(II) complexes ( 1- 8) with two ONS donor thiosemicarbazone ligands {salicylaldehyde 3-hexamethyleneiminyl thiosemicarbazone [H 2L 1] and salicylaldehyde 3-tetramethyleneiminyl thiosemicarbazone [H 2L 2]} have been prepared and physico-chemically characterized. IR, electronic and EPR spectra of the complexes have been obtained. The thiosemicarbazones bind to metal as dianionic ONS donor ligands in all the complexes except in [Cu(HL 1) 2] ( 2) and [Cu(HL 2) 2] ( 6). In compounds 2 and 6 the ligands are coordinated as monoanionic HL - ones. The magnetic susceptibility measurements indicate that all the complexes are paramagnetic. In complex [(CuL 1) 2] ( 1), the magnetic moment value is lower than the expected spin only value. In all the complexes g|| > g⊥ > 2.0023 and G values within the range 2.5-3.5 are consistent with d ground state. The complexes were given the formula as [(CuL 1) 2] ( 1); [Cu(HL 1) 2] ( 2); [CuL 1bpy] ( 3); [CuL 1phen] ( 4); [CuL 1γ-pic]·2H 2O ( 5); [Cu(HL 2) 2] ( 6); [CuL 2py]·3H 2O ( 7); [CuL 2bipy] ( 8). The structure of the compound 8 have been solved by single crystal X-ray crystallography and was found to be distorted square pyramid around copper(II) ion.

  14. Partial conversion of thioamide into nitrile in a copper(II) complex of 2,6-diacetylpyridine bis(thiosemicarbazone), a drug prototype for Alzheimer's disease.

    PubMed

    Vieira, Rafael P; Thompson, John R; Beraldo, Heloisa; Storr, Tim

    2015-06-01

    This work reports the crystal structure of [(Z)-2-((E)-1-{6-[1-({[amino(sulfanidyl-κS)methylidene]amino}imino-κN)ethyl]pyridin-2-yl-κN}ethylidene)-1-cyanohydrazinido-κN(1)]copper(II), [Cu(C11H11N7S)], the first description of a copper(II) complex of 2,6-diacetylpyridine bis(thiosemicarbazone) showing partial conversion of a thioamide group to a nitrile group. The asymmetric ligand coordinates to the metal centre in an N,N',N'',S-tetradentate manner via the pyridine N atom, an imine N atom, the hydrazinide N atom and the sulfanidyl S atom, displaying a square-planar geometry. Ligand coordination results in two five-membered chelate rings and one six-membered chelate ring, and in crystal packing based on N-H···N hydrogen bonds of the cyanohydrazinide and hydrazinecarbothioamidate arms of the ligand. The correlation between the partial conversion upon metal complexation, H2S release and possible effects on the activity of bis(thiosemicarbazone)s as drug prototypes for Alzheimer's disease is also discussed. PMID:26044321

  15. Rational design of a novel azoimine appended maleonitrile-based Salen chemosensor for rapid naked-eye detection of copper(II) ion in aqueous media.

    PubMed

    Rezaeian, Khatereh; Khanmohammadi, Hamid; Arab, Vajihe

    2015-12-01

    Achieving specific selectivity and high sensitivity for the colorimetric recognition of copper(II) ions in aqueous media over a complex background of potentially competing metal ions is inherently challenging in sensor development. Thus, a novel azo-azomethine receptor (L) based on the combination of 2-amino-3-(5-bromo-2-hydroxybenzylamino)maleonitrile and azo-coupled salicylaldehyde scaffold has been designed and synthesized for the naked-eye and rapid detection of Cu(2+) ion at trace level in a wide pH range. Accordingly, the devised chemosensor distinguished Cu(2+) from other metal ions by distinct color change from light yellow to light brown without any expensive equipment. The binding stoichiometry between Cu(2+) and L has been investigated using Job's plot and MALDI-TOF mass analysis. Remarkably, the current sensor can detect Cu(2+) ions even at 1.07 μM level, which is lower than the World Health Organization (WHO) permissible level (30 μM) in drinking water. Furthermore, sensor L was successfully utilized in the preparation of test strips for the detection of copper(II) ions from aqueous environment. PMID:26184468

  16. DNA- and BSA-binding studies and anticancer activity against human breast cancer cells (MCF-7) of the zinc(II) complex coordinated by 5,6-diphenyl-3-(2-pyridyl)-1,2,4-triazine

    NASA Astrophysics Data System (ADS)

    Anjomshoa, Marzieh; Fatemi, Seyed Jamilaldin; Torkzadeh-Mahani, Masoud; Hadadzadeh, Hassan

    2014-06-01

    Binding studies of a mononuclear zinc(II) complex, [Zn(dppt)2Cl2] (dppt is 5,6-diphenyl-3-(2-pyridyl)-1,2,4-triazine), with DNA and bovine serum albumin (BSA) have been investigated under physiological conditions. The binding properties of the complex with fish sperm DNA (FS-DNA) have been investigated by UV-Vis absorption, thermal denaturation, competitive DNA-binding studies with ethidium bromide (EB) by fluorescence, and gel electrophoresis techniques. The competitive study with (EB) shows that the complex can displace EB from the DNA-EB system and compete for the DNA-binding sites with EB, which is usually characteristic of the intercalative interaction of compounds with DNA. The value of the fluorescence quenching constant (Ksv) was obtained as 3.1 × 104 M-1, indicating that this complex shows a high quenching efficiency and a significant degree of binding to DNA. Moreover, the intercalative binding mode has also been verified by the results of UV-Vis absorption, thermal denaturation and gel electrophoresis. The value of Kb at room temperature was calculated to be 1.97 × 105 M-1, indicating that the complex possesses strong tendency to bind with DNA. This value is very greater than to the values obtained for other zinc(II) complexes. The interaction of the complex with BSA has been studied by UV-Vis absorption, fluorescence and circular dichroism (CD) spectroscopic techniques. The results indicate that the complex has a quite strong ability to quench the fluorescence of BSA and the binding reaction is mainly a static quenching process. The quenching constants (KSV), the binding constants (Kb), the number of binding sites at different temperatures, the binding distance between BSA and the complex (r), and the thermodynamic parameters (ΔHo, ΔSo and ΔGo) between BSA and the complex were calculated. The complex exhibits good binding propensity to BSA showing relatively high binding constant values. The positive ΔHo and ΔSo values indicate that the

  17. Synthesis, structure, magnetism and nuclease activity of tetranuclear copper(II) phosphonates contatining ancillary 2,2'-bipyridine or 1,10-phenanthroline ligands

    SciTech Connect

    Chandrasekhar, V.; Azhakar, R.; Senapati, T.; Thilagar, P.; Gosh, S.; Verma, S.; Boomishankar, R.; Steiner, A.; Kogerler, P.

    2008-01-07

    The reaction of cyclohexylphosphonic acid (C{sub 6}H{sub 11}PO{sub 3}H{sub 2}), anhydrous CuCl{sub 2} and 2,2{prime}-bipyridine (bpy) in the presence of triethylamine followed by a metathesis reaction with KNO{sub 3} afforded [Cu{sub 4}({micro}-Cl){sub 2}({micro}{sub 3}-C{sub 6}H{sub 11}PO{sub 3}){sub 2}(bpy){sub 4}](NO{sub 3}){sub 2} (1). In an analogous reaction involving Cu(OAc){sub 2} {center_dot} H{sub 2}O, the complex [Cu{sub 4}({micro}-CH{sub 3}COO){sub 2}({micro}{sub 3}-C{sub 6}H{sub 11}PO{sub 3}){sub 2}(2,2-bpy){sub 4}](CH{sub 3}COO){sub 2} (2) has been isolated. The three-component reaction involving Cu(NO{sub 3}){sub 2} {center_dot} 3H{sub 2}O, cyclohexylphosphonic acid and 2,2{prime}-bipyridine in the presence of triethylamine afforded the tetranuclear assembly [Cu{sub 4}({micro}-OH)({micro}{sub 3}-C{sub 6}H{sub 11}PO{sub 3}){sub 2}(2,2{prime}-bpy){sub 4} (H{sub 2}O){sub 2}](NO{sub 3}){sub 3} (3). Replacing 2,2{prime}-bipyridine with 1,10-phenanthroline (phen) in the above reaction resulted in [Cu{sub 4}({micro}-OH)({micro}{sub 3}-C{sub 6}H{sub 11}PO{sub 3}){sub 2}(phen){sub 4}(H{sub 2}O){sub 2}](NO{sub 3}){sub 3} (4). In all the copper(II) phosphonates (1-4) the two phosphonate ions bridge the four copper(II) ions in a capping coordination action. Each phosphonate ion bridges four copper(II) ions in a {micro}{sub 4}, coordination mode or 4.211 of the Harris notation. Variable-temperature magnetic studies on 1-4 reveal that all four complexes exhibit moderately strong intramolecular antiferromagnetic coupling. The DNA cleavage activity of complexes 1-4 is also described. Compounds 1 and 3 were able to completely convert the supercoiled pBR322 DNA form I to nick form II without any co-oxidant. In contrast, 50% conversion occurred with 2 and 40% with 4. In the presence of magnesium monoperoxyphthalate all four compounds achieved rapid conversion of form I to form II.

  18. Spectral, electrochemical and molecular orbital studies on solvatochromic mixed ligand copper(II) complexes of malonate and diamine derivatives

    NASA Astrophysics Data System (ADS)

    Taha, Ali

    2003-04-01

    Solvatochromic mixed ligand complexes of copper(II) with malonate and diamine derivatives, Cu n(RMal)(diam) nXm (where n=1 or 2, m=1-4, RMal, malonic acid (H 2Mal), diethylmalonate (HDEtMal) or diethylethoxyethylenemalonate (DEtEMal), and diam, ethylenediamine (en), 1,3-propylenediamine (1,3-pn), N, N, N'-trimethylethylenediamine (Me 3en), N, N, N'-triethylethylenediamine (Et 3en), N, N, N', N'-tetramethylethylenediamine (Me 4en), N, N, N', N'-tetramethylpropylenediamine (Me 4pn), or N-methyl-1,4-diazacycloheptane (medach); and X=ClO 4- or Cl -), has been synthesized and characterized by spectroscopic, magnetic, molar conductance and electrochemical measurements. The mass spectra along with the analytical data of the complexes show peaks with m/ e corresponding to a bridged binuclear structure for the chloride complexes, while perchlorate complexes showed either mononuclear structure for DEtMal and DEtEMal or bridged binuclear structure for Mal complexes. These results correspond to IR spectral data, which indicated that the modes of ester and carboxylato coordination sites are mono- and/or bidentate. The d-d absorption bands in weak donor solvents suggest square-planar and distorted square pyramidal-trigonal bipyramid geometries for the perchlorate and chloride complexes; respectively. On the other hand, an octahedral structure is identified for complexes in strong donor solvents. Perchlorate complexes show a drastic color change from violet to green as the donation ability of solvent increases, whereas chloride complexes are highly affected by the acceptor properties of the solvent. Cyclic voltammetric measurements on the complexes, proposed a quasi-reversible or irreversible and mainly diffusion controlled reduction process. Such behavior has been explained according to the ECE mechanism. A linear correlation has been found between the Cu(II) reduction potential and the spectral data. Molecular orbital calculations were performed for the ligands on the bases of

  19. In Vitro Activity of Copper(II) Complexes, Loaded or Unloaded into a Nanostructured Lipid System, against Mycobacterium tuberculosis

    PubMed Central

    da Silva, Patricia B.; de Souza, Paula C.; Calixto, Giovana Maria Fioramonti; Lopes, Erica de O.; Frem, Regina C. G.; Netto, Adelino V. G.; Mauro, Antonio E.; Pavan, Fernando R.; Chorilli, Marlus

    2016-01-01

    Tuberculosis (TB) is an infectious disease caused mainly by the bacillus Mycobacterium tuberculosis (Mtb), presenting 9.5 million new cases and 1.5 million deaths in 2014. The aim of this study was to evaluate a nanostructured lipid system (NLS) composed of 10% phase oil (cholesterol), 10% surfactant (soy phosphatidylcholine, sodium oleate), and Eumulgin® HRE 40 ([castor oil polyoxyl-40-hydrogenated] in a proportion of 3:6:8), and an 80% aqueous phase (phosphate buffer pH = 7.4) as a tactic to enhance the in vitro anti-Mtb activity of the copper(II) complexes [CuCl2(INH)2]·H2O (1), [Cu(NCS)2(INH)2]·5H2O (2) and [Cu(NCO)2(INH)2]·4H2O (3). The Cu(II) complex-loaded NLS displayed sizes ranging from 169.5 ± 0.7095 to 211.1 ± 0.8963 nm, polydispersity index (PDI) varying from 0.135 ± 0.0130 to 0.236 ± 0.00100, and zeta potential ranging from −0.00690 ± 0.0896 to −8.43 ± 1.63 mV. Rheological analysis showed that the formulations behave as non-Newtonian fluids of the pseudoplastic and viscoelastic type. Antimycobacterial activities of the free complexes and NLS-loaded complexes against Mtb H37Rv ATCC 27294 were evaluated by the REMA methodology, and the selectivity index (SI) was calculated using the cytotoxicity index (IC50) against Vero (ATCC® CCL-81), J774A.1 (ATCC® TIB-67), and MRC-5 (ATCC® CCL-171) cell lines. The data suggest that the incorporation of the complexes into NLS improved the inhibitory action against Mtb by 52-, 27-, and 4.7-fold and the SI values by 173-, 43-, and 7-fold for the compounds 1, 2 and 3, respectively. The incorporation of the complexes 1, 2 and 3 into the NLS also resulted in a significant decrease of toxicity towards an alternative model (Artemia salina L.). These findings suggest that the NLS may be considered as a platform for incorporation of metallic complexes aimed at the treatment of TB. PMID:27196901

  20. Mechanochemical synthesis in copper(II) halide/pyridine systems: single crystal X-ray diffraction and IR spectroscopic studies.

    PubMed

    Bowmaker, Graham A; Di Nicola, Corrado; Pettinari, Claudio; Skelton, Brian W; Somers, Neil; White, Allan H

    2011-05-14

    Whereas complexes of divalent metal halides (X = Cl, Br, I) with/from pyridine commonly crystallise as trans-[M(py)(4)X(2)]·2py, M on a site of 222 symmetry in space group Ccca, true for CuCl(2) and CuBr(2) in particular, the copper(II) iodide adduct is of the form [Cu(py)(4)I]I·2py, Cu on a site of mm2 symmetry in space group Cmcm, and five-coordinate (square-pyramidal), the same cationic species also being found in 2[Cu(py)(4)I](I(3))·[(py)(2)Cu(μ-I)(2)Cu(py)(2)] (structurally defined). Bromide or N-thiocyanate may be substituted for the unbound iodide ion in the solvated salt, resulting in complexes which crystallize in space group Ccca, but with both anions and the metal atom disordered. In [Cu(py)(4)(I(3))(2)], a pair of long Cu···I contacts approach a square-planar Cu(py)(4) array. Assignments of the ν(CuN) and ν(CuX) (X = Br, I, SCN) bands in the far-IR spectra are made, the latter with the aid of analogous assignments for [Cu(py)(2)X(2)] (X = Cl, Br), which show a dependence of ν(CuX) on the Cu-X bond length that is very similar to that determined previously for copper(i) halide complexes. The structure of the adventitious complex [(trans-)(H(2)O)(py)(4)CuClCu(py)(4)](I(3))(3)·H(2)O is also recorded, with six- and five-coordinate copper atoms; rational synthesis provides [{Cu(py)(4)}(2)(μ-Cl)](I(3))(3)·H(2)O with one water molecule less. In [{Cu(py)(4)Cl}((∞|∞))](I(3))·3py, square pyramidal [Cu(py)(4)Cl](+) cations, assisted by Cl···Cu interactions, stack to give rise to infinite polymeric strings. Several of these compounds were prepared mechanochemically, illustrating the applicability of this method to syntheses involving redox reactions as well as to complex syntheses involving up to five components. The totality of results demonstrates that the [Cu(II)(py)(4)] entity can be stabilized in an unexpectedly diverse range of mononuclear and multinuclear complexes through the presence of lattice pyridine molecules, the bulky triiodide

  1. Theoretical Proposal for the Whole Phosphate Diester Hydrolysis Mechanism Promoted by a Catalytic Promiscuous Dinuclear Copper(II) Complex.

    PubMed

    Esteves, Lucas F; Rey, Nicolás A; Dos Santos, Hélio F; Costa, Luiz Antônio S

    2016-03-21

    The catalytic mechanism that involves the cleavage of the phosphate diester model BDNPP (bis(2,4-dinitrophenyl) phosphate) catalyzed through a dinuclear copper complex is investigated in the current study. The metal complex was originally designed to catalyze catechol oxidation, and it showed an interesting catalytic promiscuity case in biomimetic systems. The current study investigates two different reaction mechanisms through quantum mechanics calculations in the gas phase, and it also includes the solvent effect through PCM (polarizable continuum model) single-point calculations using water as solvent. Two mechanisms are presented in order to fully describe the phosphate diester hydrolysis. Mechanism 1 is of the SN2 type, which involves the direct attack of the μ-OH bridge between the two copper(II) ions toward the phosphorus center, whereas mechanism 2 is the process in which hydrolysis takes place through proton transfer between the oxygen atom in the bridging hydroxo ligand and the other oxygen atom in the phosphate model. Actually, the present theoretical study shows two possible reaction paths in mechanism 1. Its first reaction path (p1) involves a proton transfer that occurs immediately after the hydrolytic cleavage, so that the proton transfer is the rate-determining step, which is followed by the entry of two water molecules. Its second reaction path (p2) consists of the entry of two water molecules right after the hydrolytic cleavage, but with no proton transfer; thus, hydrolytic cleavage is the rate-limiting step. The most likely catalytic path occurs in mechanism 1, following the second reaction path (p2), since it involves the lowest free energy activation barrier (ΔG(⧧) = 23.7 kcal mol(-1), in aqueous solution). A kinetic analysis showed that the experimental kobs value of 1.7 × 10(-5) s(-1) agrees with the calculated value k1 = 2.6 × 10(-5) s(-1); the concerted mechanism is kinetically favorable. The KIE (kinetic isotope effect) analysis

  2. Copper(II) complexes with the non-steroidal anti-inflammatory drug tolfenamic acid: Structure and biological features.

    PubMed

    Tarushi, Alketa; Perontsis, Spyros; Hatzidimitriou, Antonios G; Papadopoulos, Athanasios N; Kessissoglou, Dimitris P; Psomas, George

    2015-08-01

    Copper(II) complexes with the non-steroidal anti-inflammatory drug tolfenamic acid (Htolf) with the oxygen-donor ligands methanol (MeOH) or N,N-dimethylformamide (DMF) and/or the nitrogen-donor heterocyclic ligands 2,2'-bipyridine (bipy), 2,2'-bipyridylamine (bipyam), 1,10-phenanthroline (phen) or pyridine (py) were synthesized and characterized. The crystal structures of five novel complexes were determined by X-ray crystallography where tolfenamic acid is deprotonated being in different binding modes. Equimolar quantities of CuCl2, tolf(-1) and bipy led to the formation of [Cu(tolf-O,O')(bipy)Cl] (1), while with a 1:2 Cu(II):tolf ratio, complexes [Cu(tolf-O,O')2(bipy)] (2), [Cu(tolf-O,O')2(bipyam)] · 0.5MeOH (3 0.5MeOH), [Cu(tolf-O,O')(tolf-O)(phen)(MeOH)] (4) and [Cu(tolf-O)2(py)2(MeOH)2] (5) were isolated. The interaction of the complexes with serum albumin proteins was studied by fluorescence spectroscopy with the determined binding constant bearing relative high values. The scavenging ability of the complexes towards 1,1-diphenyl-picrylhydrazyl, 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) and hydroxyl radicals was investigated and the in vitro inhibitory activity against soybean lipoxygenase was evaluated and complexes 4 and 5 were the more active compounds among those tested. Spectroscopic (UV), electrochemical (cyclic voltammetry) and physicochemical (viscosity measurements) techniques were employed in order to study the binding mode and strength of the complexes to calf-thymus (CT) DNA suggesting intercalation as the most possible mode of binding. Competitive studies with ethidium bromide (EB) revealed the ability of the complexes to displace the DNA-bound EB. The biological properties of complexes 1-5 were evaluated in regard to previously reported complex [Cu2(tolf-O,O')4(DMF)2] (6). PMID:25824465

  3. In Vitro Activity of Copper(II) Complexes, Loaded or Unloaded into a Nanostructured Lipid System, against Mycobacterium tuberculosis.

    PubMed

    Silva, Patricia B da; Souza, Paula C de; Calixto, Giovana Maria Fioramonti; Lopes, Erica de O; Frem, Regina C G; Netto, Adelino V G; Mauro, Antonio E; Pavan, Fernando R; Chorilli, Marlus

    2016-01-01

    Tuberculosis (TB) is an infectious disease caused mainly by the bacillus Mycobacterium tuberculosis (Mtb), presenting 9.5 million new cases and 1.5 million deaths in 2014. The aim of this study was to evaluate a nanostructured lipid system (NLS) composed of 10% phase oil (cholesterol), 10% surfactant (soy phosphatidylcholine, sodium oleate), and Eumulgin(®) HRE 40 ([castor oil polyoxyl-40-hydrogenated] in a proportion of 3:6:8), and an 80% aqueous phase (phosphate buffer pH = 7.4) as a tactic to enhance the in vitro anti-Mtb activity of the copper(II) complexes [CuCl₂(INH)₂]·H₂O (1), [Cu(NCS)₂(INH)₂]·5H₂O (2) and [Cu(NCO)₂(INH)₂]·4H₂O (3). The Cu(II) complex-loaded NLS displayed sizes ranging from 169.5 ± 0.7095 to 211.1 ± 0.8963 nm, polydispersity index (PDI) varying from 0.135 ± 0.0130 to 0.236 ± 0.00100, and zeta potential ranging from -0.00690 ± 0.0896 to -8.43 ± 1.63 mV. Rheological analysis showed that the formulations behave as non-Newtonian fluids of the pseudoplastic and viscoelastic type. Antimycobacterial activities of the free complexes and NLS-loaded complexes against Mtb H37Rv ATCC 27294 were evaluated by the REMA methodology, and the selectivity index (SI) was calculated using the cytotoxicity index (IC50) against Vero (ATCC(®) CCL-81), J774A.1 (ATCC(®) TIB-67), and MRC-5 (ATCC(®) CCL-171) cell lines. The data suggest that the incorporation of the complexes into NLS improved the inhibitory action against Mtb by 52-, 27-, and 4.7-fold and the SI values by 173-, 43-, and 7-fold for the compounds 1, 2 and 3, respectively. The incorporation of the complexes 1, 2 and 3 into the NLS also resulted in a significant decrease of toxicity towards an alternative model (Artemia salina L.). These findings suggest that the NLS may be considered as a platform for incorporation of metallic complexes aimed at the treatment of TB. PMID:27196901

  4. Zinc(II) and lead(II) metal-organic networks driven by a multifunctional pyridine-carboxylate building block: Hydrothermal synthesis, structural and topological features, and luminescence properties

    NASA Astrophysics Data System (ADS)

    Yang, Ling; Li, Yu; You, Ao; Jiang, Juan; Zou, Xun-Zhong; Chen, Jin-Wei; Gu, Jin-Zhong; Kirillov, Alexander M.

    2016-09-01

    4-(5-Carboxypyridin-2-yl)isophthalic acid (H3L) was applied as a flexible, multifunctional N,O-building block for the hydrothermal self-assembly synthesis of two novel coordination compounds, namely 2D [Zn(μ3-HL)(H2O)]n·nH2O (1) and 3D [Pb2(μ5-HL)(μ6-HL)]n (2) coordination polymers (CPs). These compounds were obtained in aqueous medium from a mixture containing zinc(II) or lead(II) nitrate, H3L, and sodium hydroxide. The products were isolated as stable crystalline solids and were characterized by IR spectroscopy, elemental, thermogravimetric (TGA), powder (PXRD) and single-crystal X-ray diffraction analyses. Compound 1 possesses a 2D metal-organic layer with the fes topology, which is further extended into a 3D supramolecular framework via hydrogen bonds. In contrast, compound 2 features a very complex network structure, which was topologically classified as a binodal 5,6-connected net with the unique topology defined by the point symbol of (47.63)(49.66). Compounds 1 and 2 disclose an intense blue or green luminescent emission at room temperature.

  5. Photochemical activation of carbon dioxide by visible light mediated by cobalt(II) and nickel(II) complexes of 1,6-bis(benzimidazol-2-YL)-2, 5-dithiahexane (BBDH)

    SciTech Connect

    Carballo, R.; Castineiras, A.; Hiller, W.; Straehle, J.

    1996-12-01

    Reactions between crystalline Ni(NO{sub 3}){sub 2} or Co(ClO{sub 4}){sub 2} 6H{sub 2}O and 1,6-bis(benzimidazol-2-yl)-2, 5-dithiahexane (BBDH) in ethanol afford the insolubles [Ni(BBDH)(H{sub 2}O){sub 2}](NO{sub 3}){sub 2} or [Co(BBDH)(H{sub 2}O){sub 2}](ClO{sub 4}){sub 2} and coloured solutions. The action of CO{sub 2} and visible light on these suspensions at room temperature yields new nickel(II) or cobalt(II) 2-carboxylato benzimidazolates, [O{sub 2}C-BzIm]{sup 2{minus}}, of formula [Ni{sub 2}(BBDH){sub 2}({mu}{sub 2}-O{sub 2}C-BzIm)](NO{sub 3}){sub 2} (I) and [Co{sub 2}(BBDH){sub 2}({mu}{sub 2}-O{sub 2}-c-BzIm)] (ClO{sub 4}){sub 2} (II), respectively. The crystal and molecular structure of I and II have been elucidated by single crystal X-ray analysis. The complex I crystallizes in the monoclinic space group C2/c, with a = 15.371(3), b = 13.393(3), c = 22.790 (4) {angstrom}, and {beta} = 99.54(4){degrees}. The unit cell comprises four formula units with half the binuclear cation complex in the asymmetric unit. The [O{sub 2}-C-BzIm]{sup 2{minus}} bridges two distorted octahedral nickel(II) ions having a Ni-Ni distance of 5.397(2) {angstrom}. Complex II crystallizes in the triclinic space group P1, with cell data a = 13.351(5), b = 18.960(5), c = 11.379(3) {angstrom},{alpha} = 91.14(2), {beta} = 107.93(3), and {gamma} = 100.88(3){degrees}. The cation complex consists of a dimeric unit with two distorted octahedral cobalt(II) ions being bridged by a 2-carboxylatobenzimidazolato anion, with a Co-Co distance of 5.285(6) {angstrom}. IR spectra are reported. A plausible mechanism by which complexes I and II are formed is also reported. 58 refs.

  6. Enantio- and Chemoselective Differentiation of Protected α-Amino Acids and β-Homoamino Acids With A Single CopperII Host

    PubMed Central

    Joyce, Leo A.; Canary, James W.

    2012-01-01

    The association between an achiral copperII containing host 1 and chiral carboxylates has been expanded beyond previous studies to new chiral carboxylate guests, both α-amino acids and β-homoamino acids. The observed exciton-coupled circular dichroism (ECCD) signals for the enantiomers of each carboxylate were equal and opposite, and these signals differed in size and shape between the individual amino acids. Linear discriminant analysis (LDA) was applied as a statistical analysis technique to differentiate the amino acids, both enantioselectively and chemoselectively, giving the absolute configuration and identity of the amino acid. The identity of each of the α-amino acids and β-homoamino acids were determined independently by LDA analysis, and then the two were considered together. Each of these analyses showed good differentiation of the amino acid guests with the use of only one host molecule. PMID:22592912

  7. Variation in DNA binding constants with a change in geometry of ternary copper(II) complexes with N2O donor Schiff base and cyanate or dicyanamide

    NASA Astrophysics Data System (ADS)

    Jana, Subrata; Santra, Ramesh Chandra; Das, Saurabh; Chattopadhyay, Shouvik

    2014-09-01

    Two new copper(II) complexes, [Cu(L)(OCN)] (1) and [CuL(dca)]n (2), where HL = 2-(-(2-(diethylamino)ethylimino)methyl)naphthalen-1-ol, dca = N(CN)2-, have been synthesized and characterized by elemental analysis, IR, UV-VIS spectroscopy and single crystal X-ray diffraction studies. Complex 1 has square planar and complex 2 square pyramidal geometries in solid state around metal centre. Interactions of the complexes with calf thymus DNA (CT DNA) were studied by UV-VIS spectroscopy. Binding constant and site size of interaction were determined. Binding site size and intrinsic binding constant K revealed complex 1 interacted with calf thymus DNA better than complex 2.

  8. Facile synthesis of gold coated copper(II) hydroxide pine-needle-like micro/nanostructures for surface-enhanced Raman scattering

    NASA Astrophysics Data System (ADS)

    Long, Kailin; Du, Deyang; Luo, Xiaoguang; Zhao, Weiwei; Wu, Zhangting; Si, Lifang; Qiu, Teng

    2014-08-01

    This work reports a facile method to fabricate gold coated copper(II) hydroxide pine-needle-like micro/nanostructures for surface-enhanced Raman scattering (SERS) application. The effects of reaction parameters on the shape, size and surface morphology of the products are systematically investigated. The as-prepared 3D hierarchical structures have the advantage of a large surface area available for the formation of hot spots and the adsorption of target analytes, thus dramatically improving the Raman signals. The finite difference time domain calculations indicate that the pine-needle-like model pattern may demonstrate a high quality SERS property owing to the high density and abundant hot spot characteristic in closely spaced needle-like arms.

  9. Synthesis and characterization of Copper(II) complexes of an azo dye derived from 4-amino-2,3-dimethyl-1-phenyl-3-pyrazolin-5-one

    NASA Astrophysics Data System (ADS)

    Kumar, V. G. Viju; Rajan, Nidhy Mary

    2014-10-01

    Azo dye based metal complexes have been found potential applications for molecular memory storage and nonlinear optical elements. Copper(II) complexes with azo dye derived from 4-amino-2,3-dimethyl-1-phenyl-3-pyrazolin-5-one with p-cresol, m-cresol and o-cresol having the composition [CuL2Cl2] were synthesized. The Complexes were characterized by elemental analysis, electrical conductance, magnetic susceptibility, mass spectroscopy, 1H-NMR, ESR, IR, UV-Vis spectroscopy and TG-DTG technique. The IR spectra suggest the ligand act as neutral bidentate ligand and complexes are monomeric and non-electrolytes. A distorted octahedral geometry was suggested for all the three complexes. The thermal decomposition characteristics have been studied and kinetic parameters were calculated using Coats-Redfern equation. The biological activity of complex was investigated.

  10. Photochemistry of transition-metal phthalocyanines. Monophotonic and sequential biphotonic photochemical processes of copper(II) tetrakis(N-octadecylsulfamoyl)phthalocyanine in nonaqueous media

    SciTech Connect

    Prasad, D.R.; Ferraudi, G.

    1982-08-01

    The photochemistry of dimeric and monomeric copper(II) tetrakis(N-octadecylsulfamoyl)phthalocyanine in chloroform has been investigated by steady-state, flash and laser flash photolysis. The decay of a low-lying ..pi pi..* triplet-doublet with k approx. = 2 x 10/sup 7/ s/sup -1/ was observed in laser flash photolysis. Similar observations were carried out with related complexes. Moreover, long-lived transformations were assigned to the formation of a copper(III) phthalocyanine. Product yields were determined as a function of the excitation wavelength and light intensity. Excitations on the Q band, lambda approx. = 600 nm, with high intensities from a focused dye laser induce a photochemistry otherwise observed for excitations at lambda less than or equal to 350 nm. Mechanisms involving short-lived n..pi..* states and two-photon photochemistry involving a low-lying and long-lived ..pi pi..* triplet-doublet are discussed. 6 figures, 2 tables.

  11. Investigation of copper(II) binding to the protein precursor of Non-Amyloid-Beta Component of Alzheimer Disease Amyloid Plaque

    NASA Astrophysics Data System (ADS)

    Rose, Francis; Hodak, Miroslav; Bernholc, Jerry

    2007-03-01

    The Non-Amyloid-Beta Component Precursor (NACP) is a natively unfolded synaptic protein that is implicated in Alzheimers and Parkinsons diseases. Its aggregation into fibrillar structures is accelerated by the binding of copper(II). Experimental studies suggest that the dominant copper binding site is located at the histidine residue in NACP. Based on this evidence we assembled a model fragment of the binding site and used DFT to analyze the conformational details of the most probable binding motifs. We investigated the overall conformational effects with classical MD by constraining the copper binding site to the most energetically favorable geometry obtained from the DFT calculations. These results are compared and contrasted with those of the unbound NACP.

  12. Structural and spectropscopic studies of a three-dimensional hydrogen-bonded copper(II) complex: aqua[bis(pyridin-2-ylcarbonyl)amidato]cyanidocopper(II).

    PubMed

    Wang, Jiang-Yun

    2015-02-01

    The preparation and X-ray and spectroscopic studies of the title copper(II) complex, [Cu(C12H8N3O2)(CN)(H2O)], are reported. The Cu(II) cation is five-coordinated, forming a distorted square-planar pyramid with an Addison τ parameter of 0.14. The UV-vis spectrum shows a d-d transition of the Cu(II) centre at 638 nm, and the electron paramagnetic resonance (EPR) spectrum confirms that the Cu(II) cation has an axial symmetry coordination and that the unpaired electrons occupy the d(x(2)-y(2)) orbital. Cyclic voltammetric studies show two irreversible oxidation and reduction peaks. PMID:25652287

  13. Synthesis, spectral, photolysis and electrochemical studies of mononuclear copper(II) complex with a new asymmetric tetradentate ligand: Application as copper nanoparticle precursor

    NASA Astrophysics Data System (ADS)

    Habibi, Mohammad Hossein; Mikhak, Maryam

    2012-10-01

    A copper(II) complex with asymmetric tetradentate Schiff base ligand, obtained by the single condensation of 1,2-diaminopropane with 2-hydroxy-5-methoxy benzaldehyde was prepared. The ligand and complex were characterized by their IR, UV-Vis, FT-IR, NMR spectra and CV. Crystal structures of the mononuclear copper complex have been obtained by X-ray diffraction studies which revealed to be distorted square planner coordination geometry. The spectral data confirm coordination of ligand to copper ion center. The redox properties of complex at different scan rates exhibit grossly similar features consisting of an electrochemically pseudo-reversible Cu(II)/Cu(I) reduction at ca. -0.97 V and pseudo-reversible Cu(I)/Cu(II) oxidation at ca. -0.81 V. The copper nanoparticles with average size of 73 nm were formed by thermal reduction of copper complex in the presence of triphenylphosphine.

  14. Structure, spectroscopy, and theory calculations of mononuclear mixed-ligand copper(II) complex with malonate and 2-propylimidazole, [Cu(mal)(PIM) 2(H 2O)

    NASA Astrophysics Data System (ADS)

    Peng, Xian; Cui, Guang-Hua; Li, De-Jie; Wu, Shang-Zhuo; Yu, Ya-Mei

    2010-05-01

    A mononuclear copper(II) complex, [Cu(mal)(PIM) 2(H 2O)] (1) [mal = malonate dianion, PIM = 2-propylimidazole] has been synthesized and characterized by elemental analysis, IR, UV-Vis, TG-DTA, and single crystal X-ray diffraction. The center Cu(II) atom in the complex has a distorted square-pyramidal geometry, being coordinated by two nitrogen atoms and three oxygen atoms. Density Functional Theory (DFT) with the B3LYP method and time-dependent DFT calculations were performed to provide insight into the structural, electronic, and electronic spectroscopic properties of the complex 1, and the UV-Vis spectrum of the title compound has been discussed on this basis. All the absorption bands in UV-Vis spectrum are mostly π/( P, σ) → d x2-y2 ligand-to-metal charge transfer (LMCT) transition, together with partial d → d ligand field (LF) transition.

  15. Synthesis, characterization, and theoretical calculations of mononuclear copper(II) benzoate complex with 2-propylimidazole, [Cu(PIM) 2(PhCOO) 2

    NASA Astrophysics Data System (ADS)

    Peng, Xian; Cui, Guang-hua; Li, De-jie; Liu, Tong-fei

    2010-04-01

    A mononuclear copper(II) complex, [Cu(PIM) 2(PhCOO) 2] ( 1) [where PIM = 2-propylimidazole] has been synthesized and characterized by elemental analysis, IR, UV-Vis, TGA, and single crystal X-ray diffraction. The structural analysis indicated that Cu(II) atom in the complex is six-coordinated in a distorted octahedral geometry by two N atoms from two 2-propylimidazole and four O atoms from two benzoate ligands. In addition, based on crystal structural data, quantum chemistry calculation in DFT/B3LYP level has been used to reoptimize and explore the electronic structure of the compound 1; time-dependent DFT (TD-DFT) calculations have also been performed in order to elucidate its spectroscopic properties. All parameters from the calculations are in well accordance with our experimental result.

  16. Cytotoxic, pro-apoptotic, pro-oxidant, and non-genotoxic activities of a novel copper(II) complex against human cervical cancer.

    PubMed

    Frías González, Susana E; Angeles Anguiano, Enrique; Mendoza Herrera, Alberto; Escutia Calzada, Daniel; Ordaz Pichardo, Cynthia

    2013-12-01

    Cisplatin remains one of the most effective current chemotherapeutic agents; however, metal complexes synthesis has increased in order to produce new anti-neoplastic drugs with DNA binding and apoptotic activities in tumor cells and less toxicity for patients. In this study, we evaluated the cytotoxic activity of a novel copper(II) complex (LQM402) against cervical cancer cell lines and found that LQM402 exhibited selective cytotoxicity against HeLa and Ca Ski cells. FITC-annexin assay and DNA fragmentation indicated that apoptosis could be involved in HeLa cell death. Caspase 3/7 and cytochrome c analysis by immunoblotting suggest the intrinsic pathway. LQM402 is a lipid peroxidation inductor according to TBARS production. Additionally, the Ames and micronucleus tests demonstrated non-genotoxic activity for this compound in Salmonella typhimurium and CD1 mice, respectively. Therefore, LQM402 may be a promising and safe anti-cervical cancer compound. PMID:24012731

  17. Oxidation of phenyl propyne catalyzed by copper(II) complexes of a benzimidazolyl schiff base ligand: effect of acid/base, oxidant, surfactant and morphology.

    PubMed

    Kumar, Ravinder; Mathur, Pavan

    2015-02-01

    Copper(II) complexes with a new N-Substituted benzimidazolyl schiff base ligand are used as catalyst for the oxidation of 1-phenyl propyne. The oxidation is carried out under mild conditions using stoichiometric amounts of oxidant and catalytic amounts of Cu(II) complex as catalyst. Effect of acid/base, oxidant, morphology and surfactant has been studied. Two major products of phenyl propyne oxidation are the α-diketonic product and a terminal aldehyde. Diketone is the major product under acidic conditions while aldehyde formation is highest under basic conditions. The maximum conversion is found with the NO3(-) bound complex. GC-MS is used to find the percentage yields of products. SEM and PXRD of the reused complexes as catalyst suggest that morphology affects the catalytic efficiency. PMID:25448979

  18. Solvent-Dependent Reaction Pathways Operating in Copper(II) Tetrafluoroborate Promoted Oxidative Ring-Opening Reactions of Cyclopropyl Silyl Ethers.

    PubMed

    Hasegawa, Eietsu; Nemoto, Kazuki; Nagumo, Ryosuke; Tayama, Eiji; Iwamoto, Hajime

    2016-04-01

    Oxidative ring-opening reactions of benzene-fused bicyclic cyclopropyl silyl ethers, promoted by copper(II) tetrafluoroborate, were investigated. The regioselectivity of cyclopropane ring-opening as well as product distributions were found to be highly dependent on the nature of the solvent. In alcohols, dimeric substances arising from external bond cleavage are major products. Radical rearrangement products are also formed in solvents such as ether and ethyl acetate. On the contrary, nucleophile addition to carbocation intermediates, generated by internal bond cleavage, occurs mainly in reactions taking place in acetonitrile. It is proposed that the observed solvent effects that govern the reaction pathways followed are a consequence of varying solvation of copper intermediates, which governs their reactivity and redox properties. In addition, the influence of counteranions of the copper salts, organonitriles, cyclic dienes, and substrate structures on the pathways followed in these reactions was also examined. PMID:26799089

  19. Cytotoxic, antibacterial, DNA interaction and superoxide dismutase like activities of sparfloxacin drug based copper(II) complexes with nitrogen donor ligands.

    PubMed

    Patel, Mohan N; Joshi, Hardik N; Patel, Chintan R

    2013-03-01

    The novel neutral mononuclear copper(II) complexes with fluoroquinolone antibacterial drug, sparfloxacin and nitrogen donor heterocyclic ligand have been synthesized and characterized. An antimicrobial efficiency of the complexes has been tested against five different microorganisms and showed diverse biological activity. The interaction of complex with Herring sperm (HS) DNA was investigated using viscosity titration and absorption titration techniques. The results indicate that the complexes bind to DNA by intercalative mode and have rather high DNA-binding constants. DNA cleavage study showed better cleaving ability of the complexes compare to metal salt and standard drug. All the complexes showed good cytotoxic activity with LC(50) values ranging from 4.89 to 11.94 μg mL(-1). Complexes also exhibit SOD-like activity with their IC(50) values ranging from 0.717 to 1.848 μM. PMID:23266675

  20. Crystal structures of copper(II) complexes of 2-formylpyridine substituted thiosemicarbazones; the first example of a coordinated thiosemicarbazone with a thiol function

    NASA Astrophysics Data System (ADS)

    West, D. X.; Swearingen, J. K.; Romack, T. J.; Billeh, I. S.; Jasinski, J. P.; Li, Y.; Staples, R. J.

    2001-08-01

    The crystal structures of two 5-coordinate copper(II) complexes containing neutral, tridentate 2-formylpyridine N(4)-substituted thiosemicarbazones have been determined. 2-Formylpyridine N(4)-cyclohexylthiosemicarbazone, HFo4CHex coordinates via the pyridine nitrogen, imine nitrogen and thione sulfur with two chloro ligands to produce [Cu(HFo4CHex)Cl 2]. Similarly, 2-formylpyridine 3-(4-methylpiperazine)thiosemicarbazone, HFoppz4M, produces [Cu(HFoppz4M)Cl 2] with one major difference; rather than the expected thione form of the thiosemicarbazone moiety, it coordinates as the thiol isomer. Both complexes are close to a square pyramid structure with axial and equatorial chloro ligands and the thiosemicarbazone moieties of both ligands nearly planar. Also included is the crystal structure of N-cyclohexylthiosemicarbazide, CHextsc.

  1. Oxidation of phenyl propyne catalyzed by copper(II) complexes of a benzimidazolyl schiff base ligand: Effect of acid/base, oxidant, surfactant and morphology

    NASA Astrophysics Data System (ADS)

    Kumar, Ravinder; Mathur, Pavan

    2015-02-01

    Copper(II) complexes with a new N-Substituted benzimidazolyl schiff base ligand are used as catalyst for the oxidation of 1-phenyl propyne. The oxidation is carried out under mild conditions using stoichiometric amounts of oxidant and catalytic amounts of Cu(II) complex as catalyst. Effect of acid/base, oxidant, morphology and surfactant has been studied. Two major products of phenyl propyne oxidation are the α-diketonic product and a terminal aldehyde. Diketone is the major product under acidic conditions while aldehyde formation is highest under basic conditions. The maximum conversion is found with the NO3- bound complex. GC-MS is used to find the percentage yields of products. SEM and PXRD of the reused complexes as catalyst suggest that morphology affects the catalytic efficiency.

  2. Bis[(E)-4-bromo-2-(ethoxy­imino­meth­yl)phenolato-κ2 N,O 1]copper(II)

    PubMed Central

    Gong, Shang-Sheng; Dong, Wen-Kui; Tong, Jun-Feng; Li, Li; Wu, Jian-Chao

    2009-01-01

    The title compound, [Cu(C9H9BrNO2)2], is a centrosymmetric mononuclear copper(II) complex. The Cu atom is four-coordinated in a trans-CuN2O2 square-planar geometry by two phenolate O and two oxime N atoms from two symmetry-related N,O-bidentate (E)-4-bromo-2-(ethoxy­imino­meth­yl)phenolate oxime-type ligands. An inter­esting feature of the crystal structure is the centrosymmetric inter­molecular Cu⋯O inter­action [3.382 (1) Å], which establishes an infinite chain structure along the b axis. PMID:21578195

  3. Cytotoxic, antibacterial, DNA interaction and superoxide dismutase like activities of sparfloxacin drug based copper(II) complexes with nitrogen donor ligands

    NASA Astrophysics Data System (ADS)

    Patel, Mohan N.; Joshi, Hardik N.; Patel, Chintan R.

    2013-03-01

    The novel neutral mononuclear copper(II) complexes with fluoroquinolone antibacterial drug, sparfloxacin and nitrogen donor heterocyclic ligand have been synthesized and characterized. An antimicrobial efficiency of the complexes has been tested against five different microorganisms and showed diverse biological activity. The interaction of complex with Herring sperm (HS) DNA was investigated using viscosity titration and absorption titration techniques. The results indicate that the complexes bind to DNA by intercalative mode and have rather high DNA-binding constants. DNA cleavage study showed better cleaving ability of the complexes compare to metal salt and standard drug. All the complexes showed good cytotoxic activity with LC50 values ranging from 4.89 to 11.94 μg mL-1. Complexes also exhibit SOD-like activity with their IC50 values ranging from 0.717 to 1.848 μM.

  4. Extraction of silver(I) from aqueous solutions in the absence and presence of copper(II) with a methimazole-based ionic liquid.

    PubMed

    Reyna-González, Juan M; Torriero, Angel A J; Siriwardana, Amal I; Burgar, Iko M; Bond, Alan M

    2011-08-21

    The ionic liquid (IL) 2-butylthiolonium bis(trifluoromethanesulfonyl)amide, [mimSBu][NTf(2)], facilitates the efficient extraction of silver(I) from aqueous media via interaction with both the cation and anion components of the IL. Studies with a conventional aqueous-IL two phase system as well as microextraction of silver(I) by a thick IL film adhered to an electrode monitored in situ by cyclic voltammetry, established that [mimSBu][NTf(2)] can extract electroactive silver(I) ions from an aqueous solution. The pH of the aqueous phase decreases upon addition of [mimSBu](+), which is attributed to partial release of the hydrogen attached to the N(3) nitrogen atom of the imidazolium ring. The presence of silver(I) further increase the acidity of the aqueous phase as a consequence of coordination with the IL cation component. Voltammetric and (1)H and (13)C NMR techniques have been used to establish the nature of the silver(I) complexes extracted, and show that the form of interaction with the IL differs from that outlined previously for the extraction of copper(II). Insights on the competition established when silver(I) is extracted in the presence of copper(II) are provided. Finally, it is noted that metallic silver can be directly electrodeposited at the electrode surface after extraction of silver(I) into [mimSBu][NTf(2)] and that back extraction of silver(I) into aqueous media is achieved by addition of an acidic aqueous solution. PMID:21727953

  5. Speciation of copper(II) complexes in an ionic liquid based on choline chloride and in choline chloride/water mixtures.

    PubMed

    De Vreese, Peter; Brooks, Neil R; Van Hecke, Kristof; Van Meervelt, Luc; Matthijs, Edward; Binnemans, Koen; Van Deun, Rik

    2012-05-01

    A deep-eutectic solvent with the properties of an ionic liquid is formed when choline chloride is mixed with copper(II) chloride dihydrate in a 1:2 molar ratio. EXAFS and UV-vis-near-IR optical absorption spectroscopy have been used to compare the coordination sphere of the cupric ion in this ionic liquid with that of the cupric ion in solutions of 0.1 M of CuCl(2)·2H(2)O in solvents with varying molar ratios of choline chloride and water. The EXAFS data show that species with three chloride ions and one water molecule coordinated to the cupric ion as well as species with two chloride molecules and two water molecules coordinated to the cupric ion are present in the ionic liquid. On the other hand, a fully hydrated copper(II) ion is formed in an aqueous solution free of choline chloride, and the tetrachlorocuprate(II) complex forms in aqueous choline chloride solutions with more than 50 wt % of choline chloride. In solutions with between 0 and 50 wt % of choline chloride, mixed chloro-aquo complexes occur. Upon standing at room temperature, crystals of CuCl(2)·2H(2)O and of Cu(choline)Cl(3) formed in the ionic liquid. Cu(choline)Cl(3) is the first example of a choline cation coordinating to a transition-metal ion. Crystals of [choline](3)[CuCl(4)][Cl] and of [choline](4)[Cu(4)Cl(10)O] were also synthesized from molecular or ionic liquid solvents, and their crystal structures were determined. PMID:22524435

  6. In vitro DNA and BSA-binding, cell imaging and anticancer activity against human carcinoma cell lines of mixed ligand copper(II) complexes.

    PubMed

    Anjomshoa, Marzieh; Torkzadeh-Mahani, Masoud

    2015-11-01

    Binding studies of two water soluble copper(II) complexes of the type [Cu(phen-dion)(diimine)Cl]Cl, where phen-dione is 1,10-phenanthroline-5,6-dione and diimine is 1,10-phenanthroline (1) and 2,2'-bipyridine (2), with fish sperm DNA (FS-DNA) and bovine serum albumin (BSA) have been examined under physiological conditions by a series of experimental methods (UV-Vis absorption, fluorescence, viscosity, cyclic voltammetry (CV) and circular dichroism (CD) spectroscopic techniques). The experimental results indicate that the complexes interact with FS-DNA by electrostatic and partial insertion of pyridyl rings between the base stacks of double-stranded DNA. The complexes could quench the intrinsic fluorescence of BSA with the binding constants (Kbin) of 32×10(5) M(-1) (1) and 1.7×10(5) M(-1) (2) at 290 K. The quenching mechanism, thermodynamic parameters, the number of binding sites and the effect of the Cu(II) complexes on the secondary structure of BSA have been explored. The in vitro anticancer chemotherapeutic potential of two copper(II) complexes against the three human carcinoma cell lines (MCF-7, A-549, and HT-29) and one normal cell line (DPSC) were evaluated by MTT assay. The results of in vitro cytotoxicity indicate that the complex (1) has greater cytotoxicity activity against all of the cell lines, especially HT-29 with IC50 values of 1.8 μM. Based on the IC50 values, these complexes did not display an apparent cyto-selective profile, because it would appear that two complexes are toxic to all four model cell lines. The microscopic analyses of the cancer cells confirm results of cytotoxicity. PMID:26057093

  7. Copper(II) cyanido-bridged bimetallic nitroprusside-based complexes: Syntheses, X-ray structures, magnetic properties, {sup 57}Fe Moessbauer spectroscopy and thermal studies

    SciTech Connect

    Travnicek, Zdenek; Herchel, Radovan; Mikulik, Jiri; Zboril, Radek

    2010-05-15

    Three heterobimetallic cyanido-bridged copper(II) nitroprusside-based complexes of the compositions [Cu(tet)Fe(CN){sub 5}NO].H{sub 2}O (1), where tet=N,N'-bis(3-aminopropyl)ethylenediamine, [Cu(hto)Fe(CN){sub 5}NO].2H{sub 2}O (2), where hto=1,3,6,9,11,14-hexaazatricyclo[12.2.1.1{sup 6,9}]octadecane and [Cu(nme){sub 2}Fe(CN){sub 5}NO].H{sub 2}O (3), where nme=N-methylethylenediamine, were synthesized and characterized by elemental analyses, {sup 57}Fe Moessbauer and FTIR spectroscopies, thermal analysis, magnetic measurements and single-crystal X-ray analysis. The products of thermal degradation processes of 2 and 3 were studied by XRD, {sup 57}Fe Moessbauer spectroscopy, SEM and EDS, and they were identified as mixtures of CuFe{sub 2}O{sub 4} and CuO. - Three heterobimetallic cyano-bridged copper(II) nitroprusside-based complexes of the general compositions of [Cu(L)Fe(CN){sub 5}NO].xH{sub 2}O, where L=N,N'-bis(3-aminopropyl)ethylenediamine (complex 1), 1,3,6,9,11,14-hexaazatricyclo[12.2.1.1{sup 6,9}]-octadecane (complex 2) and N-methylethylenediamine (complex 3), were synthesized, and fully structurally and magnetically characterized. SEM, EDS, XRD and {sup 57}Fe Moessbauer experiments were used for characterization of thermal decomposition products of complexes 2 and 3.

  8. Copper(II) complexes of N-(2-{[(2E)-2-(2-Hydroxy-(5-substituted)-benzylidene)-hydrazino]carbonyl}phenyl)benzamide ligands and heterocyclic coligands

    NASA Astrophysics Data System (ADS)

    Chavan, S. S.; Sawant, V. A.; Jadhav, A. N.

    2014-01-01

    Some copper(II) complexes of the type [Cu(L1-3)(phen]ṡCH2Cl2 (1a-3a) and [Cu(L1-3) (bipy)]ṡCH2Cl2 (1b-3b) (where L1 = N-(2-{[(2E)-2-(2-Hydroxy-benzylidene)-hydrazino]carbonyl}phenyl)benzamide, L2 = N-(2-{[(2E)-2-(2-Hydroxy-(5-bromo)-benzylidene)-hydrazino]carbonyl}phenyl)benzamide, L3 = N-(2-{[(2E)-2-(2-Hydroxy-(5-methoxy)-benzylidene)-hydrazino]carbonyl}phenyl)benzamide; phen = 1,10-phenanthroline, bipy = 2,2‧-bipyridine) have been prepared and characterized on the basis of elemental analyses, IR, UV-Vis and EPR spectral studies. IR spectra indicate that the ligand L1-3 exists in the keto form in the solid state, while at the time of complexation, it tautomerises into enol form. The single crystal X-ray diffraction study of the representative complex [Cu(L1) (phen)]ṡCH2Cl2 (1a) reveals the distorted square pyramidal geometry around copper(II). Crystal data of (1a): space group = P21/n, a = 11.5691(16) Å, b = 11.0885(15) Å, c = 24.890(4) Å, V = 3166.2(8) Å3, Z = 4. The electrochemical behavior of all the complexes indicate that the phen complexes appears at more positive potential as compared to those for bipy complexes, as a consequence of its stronger π acidic character. All the complexes exhibit blue-green emission as a result of the fluorescence from the intra-ligand (π → π∗) emission excited state.

  9. Synthesis of a new N-substituted bis-benzimidazolyl diamide ligand and its trinuclear copper(II) complex: Structural and fluorescence studies

    NASA Astrophysics Data System (ADS)

    Mahiya, Kuldeep; Mathur, Pavan

    2013-09-01

    The synthesis of a new N-substituted fluorescent probe based on a bis-benzimidazole diamide N2,N2‧-bis[(1-(4-methylbenzyl)-benzimidazol-2-yl)methyl]biphenyl-2,2‧-dicarboxamide (L1) with a biphenyl spacer group and its trinuclear copper(II) complex [Cu3(L1)3Cl3]ṡ3Clṡ3H2O] has been described. X-ray studies shows that the trinuclear complex crystallizes as [{Cu3(L1)3Cl3}2ṡ6Clṡ13CH3CNṡ2H2O] in triclinic space group P-1 with two independent molecules in the asymmetric unit. Each copper(II) adopts a distorted penta-coordinated geometry in each unit. The fluorescence spectra of L1 in methanol show an emission band centered at 300 nm. This band arises due to benzimidazolyl moiety in the ligating system. The diamide L1 in the presence of Fe3+ show the simultaneous ‘quenching' of (300 nm) and ‘enhancement' of (375 nm) emission band. The new emission band at 375 nm is attributed to intra ligand π-π* transition of the biphenyl moiety. While Cu2+ and Ag+ show only the quenching of the 300 nm band. No such behavior was observed with other metal ions like Ni2+, Co2+, Mn2+, Mg2+, Zn2+ and Pb2+. The quenching constant with Fe3+, Ag+ and Cu2+ are calculated by the Stern-Volmer plots.

  10. Air oxygenation chemistry of 4-TBC catalyzed by chloro bridged dinuclear copper(II) complexes of pyrazole based tridentate ligands: synthesis, structure, magnetic and computational studies.

    PubMed

    Banerjee, Ishita; Samanta, Pabitra Narayan; Das, Kalyan Kumar; Ababei, Rodica; Kalisz, Marguerite; Girard, Adrien; Mathonière, Corine; Nethaji, M; Clérac, Rodolphe; Ali, Mahammad

    2013-02-01

    Four dinuclear bis(μ-Cl) bridged copper(II) complexes, [Cu(2)(μ-Cl)(2)(L(X))(2)](ClO(4))(2) (L(X) = N,N-bis[(3,5-dimethylpyrazole-1-yl)-methyl]benzylamine with X = H(1), OMe(2), Me(3) and Cl(4)), have been synthesized and characterized by the single crystal X-ray diffraction method. In these complexes, each copper(II) center is penta-coordinated with square-pyramidal geometry. In addition to the tridentate L(X) ligand, a chloride ion occupies the last position of the square plane. This chloride ion is also bonded to the neighboring Cu(II) site in its axial position forming an SP-I dinuclear Cu(II) unit that exhibits small intramolecular ferromagnetic interactions and supported by DFT calculations. The complexes 1-3 exhibit methylmonooxygenase (pMMO) behaviour and oxidise 4-tert-butylcatechol (4-TBCH(2)) with molecular oxygen in MeOH or MeCN to 4-tert-butyl-benzoquinone (4-TBQ), 5-methoxy-4-tert-butyl-benzoquinone (5-MeO-4-TBQ) as the major products along with 6,6'-Bu(t)-biphenyl-3,4,3',4'-tetraol and others as minor products. These are further confirmed by ESI- and FAB-mass analyses. A tentative catalytic cycle has been framed based on the mass spectral analysis of the products and DFT calculations on individual intermediates that are energetically feasible. PMID:23172025

  11. Rapid, synergistic extractive spectrophotometric determination of copper(II) by using sensitive chromogenic reagent N″,N″‧-bis[(E)-(4-fluorophenyl) methylidene]thiocarbonohydrazide

    NASA Astrophysics Data System (ADS)

    Nalawade, Rekha A.; Nalawade, Avinash M.; Kamble, Ganesh S.; Anuse, Mansing A.

    2015-07-01

    A rapid and simple spectrophotometric method was developed for the determination of copper(II) by using newly synthesized chromogenic reagent, N″,N″‧-bis[(E)-(4-fluorophenyl)methylidene]thiocarbonohydrazide [bis(4-fluoroPM)TCH]. The reagent is highly sensitive and it forms yellow colored ternary complex with copper(II) in presence pyridine having composition 1:1:2 (M:L:Py) in the acidic pH range. Absorption of colored complex in amyl acetate is measured with reagent as a blank at λmax 375 nm. The synergistic effect is observed due to pyridine forming adduct with reagent in the organic phase. Beer's law was obeyed in the concentration range from 2.0 to 14 μg mL-1 for copper(II)-[bis(4-fluoroPM)TCH]-Py complex. Molar absorptivity and Sandell's sensitivity values for Cu(II)-bis(4-fluoroPM)TCH]-Py complex are 0.42545 × 105 and 0.0014 μg/cm2, respectively. The selectivity of the developed method was checked in the presence of various foreign ions. The developed method showed relative standard deviation (R.S.D.) of 0.13% for n = 10. The composition of Cu(II)-[bis(4-fluoroPM)TCH]-Py complex was determined by known methods such as Job's method of continuous variation, mole ratio method and slope ratio method. It is found that the ternary complex is stable for more than 24 h. Various factors influencing on the degree of complexation, such as, effect of pH, reagent concentration, synergent concentration, solvent etc. were studied. The accuracy and reliability of method was verified by AAS. This method is found to be simple, rapid and reproducible.

  12. Synthesis and characterization of a copper(II) complex of a ONN donor Schiff base ligand derived from pyridoxal and 2-(pyrid-2-yl)ethylamine - A novel pyridoxal based fluorescent probe

    NASA Astrophysics Data System (ADS)

    Mandal, Senjuti; Modak, Ritwik; Goswami, Sanchita

    2013-04-01

    The title complex, Cu(LH)Cl2 is the first copper(II) complex with a Schiff base derived from pyridoxal and 2-(pyrid-2-yl)ethylamine. The central metal lies in a distorted square pyramidal environment with basal plane occupied by the tridentate ONN donor ligand and a Cl atom. The apical position is occupied by another Cl atom. The existence of two different kinds of H-bonds stabilize the network that propagates as parallel layers along crystallographic b axis. The compound exhibits an irreversible CuII/CuI couple in DMF. As pyridoxal containing moieties are fluorescent in nature, its potential as a fluorescent probe is cultivated. Copper(II) ion effectively quenches the fluorescence of HL and the association constant for Cu(II) was estimated to be 10.8 × 104 M-1 in methanol by the linear Benesi-Hildebrand equation.

  13. A new Salen-type azo-azomethine ligand and its Ni(II), Cu(II) and Zn(II) complexes: Synthesis, spectral characterization, crystal structure and photoluminescence studies.

    PubMed

    Ozkan, Gozde; Kose, Muhammet; Zengin, Huseyin; McKee, Vickie; Kurtoglu, Mukerrem

    2015-11-01

    A novel Salen-type azo-azomethine ligand H2agen, 2,2'-{ethane-1,2-diylbis[nitrilomethylylidene]}bis{4-[ethylphenyldiazenyl]phenol}, formed by the 1:2M condensation of ethane-1,2-diamine with 5-[(4-ethylphenyl)diazenyl]-2-hydroxybenzaldehyde and its nickel(II), copper(II), and zinc(II) complexes were synthesized and characterized by the spectroscopic and analytical methods. The UV-vis spectra of the ligand were investigated in three organic solvents (DMSO, DMF and CHCl3). The ligand shows two absorption bands assigned to π-π(∗) and n-π(∗) transitions in the solvents used. Cu(II), and Ni(II) are tetra-coordinate binding to two phenolic oxygens and two imine nitrogens in approximate square planar geometry. Zn(II) also coordinates using the same sites like other metals but gave tetragonal configuration. Molecular structure of the Cu(II) complex [Cu(agen)] was determined by single crystal X-ray diffraction study. The X-ray data revealed that crystallographic imposed symmetry was absent for the complex molecule. In the structure, the Cu(II) ion is coordinated to two phenolate oxygen atoms and two imine nitrogen atoms of the azo-azomethine ligand with approximate square planar geometry. The ligand H2agen and its metal complexes exhibit strong blue emissions with irradiation. Fluorescence quantum yields and excited-state lifetimes for the ligand and its complexes were obtained. The H2agen ligand had a 35% quantum yield and a 3.27 ns excited-state lifetime. Complexation with metal ions caused reductions in intensities and quantum yields. PMID:26123514

  14. Biosorption of cadmium, chromium, lead, and zinc by biomass of Medicago sativa (alfalfa)

    SciTech Connect

    Gardea-Torresdey, J.L.; Gonzalez, J.H.; Tiemann, K.J.; Rodriguez, O.

    1996-12-31

    Previous laboratory batch experiments of Medicago sativa (alfalfa) indicated that the African shoots population had an excellent ability to bind copper(II) and nickel(II) ions from aqueous solution. Batch laboratory pH profile, time dependency, and capacity experiments were performed to determine the binding ability of the African shoots to cadmium(II), chromium(III), chromium(VI), lead(II), and zinc(II). Batch pH profile experiments for the mentioned ions indicated that the optimum pH for metal binding is approximately 5.0. Time dependency experiments for the metal ions showed that for all the metals studied, binding to the African alfalfa shoots occurred within five minutes. Binding capacity experiments revealed the following amounts of metal ions bound per gram of biomass: 7.1 mg Cd, 7.7 mg Cr(III), 43 mg Pb(II), and 4.9 mg Zn(II). However, no binding occurred for chromium(VI). Nearly all of the metals studied were recovered by treatment with 0.1M HCl, with the exception of chromium(III). Column experiments were performed to study the binding of Cd(II), Cr(III), Cr(VI), Pb(II), and Zn(II) to silica-immobilized African alfalfa shoots under flow conditions. These experiments showed that the silica-immobilized African alfalfa shoots were effective for removing metal ions from solution, and over 90% of the bound Pb(II), Cu(II), Ni(II), and Zn(II), and over 70% Cd(II), were recovered after treatment with four bed volumes of 0.1M HCl. The results from these studies will be useful for a novel phytofiltration technology to remove and recover heavy metal ions from aqueous solution.

  15. Synthesis, molecular modeling, thermal and spectral studies of metal complexes of hydrazone derived from 5-acetyl-4-hydroxy-2 H-1,3-thiazine-2,6(3 H)-dione and thiosemicarbazide

    NASA Astrophysics Data System (ADS)

    Adly, Omima M. I.

    2011-09-01

    Metal complexes with the general formula [ML(H 2O)(CH 3OH) x]· nH 2O·(CH 3OH) y(NO 3) z [M = Cu(II), Ni(II), Co(II), VO(IV), Cr(III), Cd(II), Zn(II) or UO 2(VI); x = 0-2; y = 0,1; z = 0,1; n = 0-2, 6 and L = hydrazone (H 2L) derived from condensation of thiosemicarbazide with 5-acetyl-4-hydroxy-2 H-1,3-thiazine-2,6(3 H)-dione. The synthesized ligand and its metal complexes have been characterized on the basis of elemental analyses, spectral and magnetic studies as well as thermal gravimetric analysis (TGA). The deprotonated ligand acts as a dibasic tridentate (ONS) via phenolate oxygen, azomethine (C dbnd N), and thiolate (C-S) groups. Copper(II) complex exhibits square planar geometry. Nickel(II), chromium(III) and dioxouranium(VI) complexes exhibit octahedral geometry. Cobalt(II), cadmium(II) and zinc(II) complexes showed tetrahedral geometry, whereas oxovanadium(IV) reveals square pyramidal geometry. Thermal analysis are investigated and showed either three or four thermal decomposition steps. Kinetic parameters ( Ea, A, Δ H, Δ S and Δ G) of the thermal decomposition stages have been evaluated using Coats-Redfern equations. The molecular parameters of the ligand and its metal complexes have been calculated and correlated with the experimental data such as IR and TGA results.

  16. Synthesis, characterization and extraction studies of some metal (II) complexes containing (hydrazoneoxime and bis-acylhydrazone) moieties.

    PubMed

    Al-Ne'aimi, Mohammed Mahmmod; Al-Khuder, Mohammed Moudar

    2013-03-15

    In this study, diacetylmonoximebenzoylhydrazone (L(1)H(2)) and 1,4-diacetylbenzene bis(benzoyl hydrazone) (L(2)H(2)) were synthesized by the condensation of benzohydrazide with diacetyl monoxime and 1,4-diacetylbenzene, respectively. Complexes of these ligands with Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) inos were prepared with a metal:ligand ratio of 1:2 for L(1)H(2) ligand, and 1:1 for L(2)H(2) ligand. The ligands and their complexes were elucidated on the basis of elemental analyses CHN, AAS, FT-IR, (1)H- and (13)C NMR spectra, UV-vis spectra and magnetic susceptibility measurements. Results show the L(1)H(2) ligand act as monoanionic O,N,N-tridentate and coordination takes place in the enol form through the oxime nitrogen, the imine nitrogen and the enolate oxygen atoms with a N(4)O(2) donor environment, while the L(2)H(2) ligand act as a dianionic O,N,N,O-tetradentate and coordination takes place in the enol form through the enolate oxygen and the azomethine nitrogen atoms with a N(2)O(2) donor environment. These results are consistent with the formation of mononuclear metal (II) complexes [M(L(1)H)(2)], and binuclear polymeric metal (II) complexes [{M(2)(L(2))}(n)]. The extraction ability of both ligands were examined in chloroform by the liquid-liquid extraction of selected transition metal [Co(2+), Ni(2+), Cu(2+), Zn(2+) and Pb(2+)] cations. The effects of pH and contact time on the percentage extraction of metal (II) ions were studied under the optimum extraction conditions. The (L(1)H(2)) ligand shows strong binding ability toward copper(II) and lead(II) ions, while the (L(2)H(2)) ligand shows strong binding ability toward nickel(II) and zinc(II) ions. PMID:23333690

  17. Synthesis, characterization and extraction studies of some metal (II) complexes containing (hydrazoneoxime and bis-acylhydrazone) moieties

    NASA Astrophysics Data System (ADS)

    Al-Ne'aimi, Mohammed Mahmmod; Al-Khuder, Mohammed Moudar

    2013-03-01

    In this study, diacetylmonoximebenzoylhydrazone (L1H2) and 1,4-diacetylbenzene bis(benzoyl hydrazone) (L2H2) were synthesized by the condensation of benzohydrazide with diacetyl monoxime and 1,4-diacetylbenzene, respectively. Complexes of these ligands with Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) inos were prepared with a metal:ligand ratio of 1:2 for L1H2 ligand, and 1:1 for L2H2 ligand. The ligands and their complexes were elucidated on the basis of elemental analyses CHN, AAS, FT-IR, 1H- and 13C NMR spectra, UV-vis spectra and magnetic susceptibility measurements. Results show the L1H2 ligand act as monoanionic O,N,N-tridentate and coordination takes place in the enol form through the oxime nitrogen, the imine nitrogen and the enolate oxygen atoms with a N4O2 donor environment, while the L2H2 ligand act as a dianionic O,N,N,O-tetradentate and coordination takes place in the enol form through the enolate oxygen and the azomethine nitrogen atoms with a N2O2 donor environment. These results are consistent with the formation of mononuclear metal (II) complexes [M(L1H)2], and binuclear polymeric metal (II) complexes [{M2(L2)}n]. The extraction ability of both ligands were examined in chloroform by the liquid-liquid extraction of selected transition metal [Co2+, Ni2+, Cu2+, Zn2+ and Pb2+] cations. The effects of pH and contact time on the percentage extraction of metal (II) ions were studied under the optimum extraction conditions. The (L1H2) ligand shows strong binding ability toward copper(II) and lead(II) ions, while the (L2H2) ligand shows strong binding ability toward nickel(II) and zinc(II) ions.

  18. Synthesis, spectroscopic, molecular orbital calculation, cytotoxic, molecular docking of DNA binding and DNA cleavage studies of transition metal complexes with N-benzylidene-N'-salicylidene-1,1-diaminopropane

    NASA Astrophysics Data System (ADS)

    Al-Mogren, Muneerah M.; Alaghaz, Abdel-Nasser M. A.; Elbohy, Salwa A. H.

    2013-10-01

    Eight mononuclear chromium(III), manganese(II), iron(III), cobalt(II), nickel(II), copper(II), zinc(II) and cadmium(II) complexes of Schiff's base ligand were synthesized and determined by different physical techniques. The complexes are insoluble in common organic solvents but soluble in DMF and DMSO. The measured molar conductance values in DMSO indicate that the complexes are non-electrolytic in nature. All the eight metal complexes have been fully characterized with the help of elemental analyses, molecular weights, molar conductance values, magnetic moments and spectroscopic data. The analytical data helped to elucidate the structure of the metal complexes. The Schiff base is found to act as tridentate ligand using N2O donor set of atoms leading to an octahedral geometry for the complexes around all the metal ions. Quantum chemical calculations were performed with semi-empirical method to find the optimum geometry of the ligand and its complexes. Additionally in silico, the docking studies and the calculated pharmacokinetic parameters show promising futures for application of the ligand and complexes as high potency agents for DNA binding activity. The interaction of the complexes with calf thymus DNA (CT-DNA) has been investigated by UV absorption method, and the mode of CT-DNA binding to the complexes has been explored. Furthermore, the DNA cleavage activity by the complexes was performed. The Schiff base and their complexes have been screened for their antibacterial activity against bacterial strains [Staphylococcus aureus (RCMB010027), Staphylococcus epidermidis (RCMB010024), Bacillis subtilis (RCMB010063), Proteous vulgaris (RCMB 010085), Klebsiella pneumonia (RCMB 010093) and Shigella flexneri (RCMB 0100542)] and fungi [(Aspergillus fumigates (RCMB 02564), Aspergillus clavatus (RCMB 02593) and Candida albicans (RCMB05035)] by disk diffusion method. All the metal complexes have potent biocidal activity than the free ligand.

  19. Synthesis, spectroscopic identification, thermal, potentiometric and antibacterial activity studies of 4-amino-5-mercapto-S-triazole Schiff's base complexes

    NASA Astrophysics Data System (ADS)

    Alaghaz, Abdel-Nasser M. A.; Zayed, Mohamed E.; Alharbi, Suliman A.; Ammar, Reda A. A.; Chinnathambi, Arunachalam

    2015-05-01

    Complexes of manganese(II), cobalt(II), nickel(II), copper(II) and zinc(II) of general composition [M(L)2] have been synthesized [L = 4-pyridin-2-yl-methylene amino-4H-1,2,4-triazole-3-thiol]. The elemental analyses, molar conductance, spectral (IR, UV-Vis, 1H NMR, mass), magnetic moment and thermal measurements studies of the compounds led to the conclusion that the ligand acts as a tridentate manner (SNN). The molar conductance of the metal complexes in fresh solution of DMSO lies in the range of 8.34-10.46 Ω-1 cm2 mol-1 indicating their non-electrolytic behavior. On the basis of analytical and spectroscopic techniques, octahedral geometry of the complexes was proposed. The Schiff base acts as tridentate ligand coordinated through deprotonated thiolic sulfur, azomethine nitrogen and pyridine nitrogen atoms. The ligand field parameters were calculated for Co(II), Ni(II) and Cu(II) complexes and their values were found in the range reported for a octahedral structure. The data show that the complexes have composition of ML2 type. The activation of thermodynamic parameters are calculated using Coast-Redfern, Horowitz-Metzger (HM), Piloyan-Novikova (PN) and Broido's equations. Protonation constants of Schiff base and stability constants of their binary metal complexes have been determined potentiometrically in 50% DMSO-water media at 25 °C and ionic strength 0.10 M potassium nitrate. Both the Schiff's base ligand and its complexes have been screened for antibacterial activities.

  20. Biological evaluation of new nickel(II) metallates: Synthesis, DNA/protein binding and mitochondrial mediated apoptosis in human lung cancer cells (A549) via ROS hypergeneration and depletion of cellular antioxidant pool.

    PubMed

    Kalaivani, P; Saranya, S; Poornima, P; Prabhakaran, R; Dallemer, F; Vijaya Padma, V; Natarajan, K

    2014-07-23

    A series of novel nickel(II) thiosemicarbazone complexes(1-4) have been prepared and characterized by various spectral, analytical techniques and X-ray crystallography. Further, their efficacy to interact with CT-DNA/BSA has been explored. From the binding studies, it is inferred that complex 4 found to be more active than other complexes. The complexes bound with CT-DNA by intercalation mode. Moreover, static quenching was observed for their interaction with BSA. The new complexes were tested for their in vitro cytotoxicity against human lung adenocarcinoma (A549) cell line. The results showed that the new complexes exhibited significant degree of cytotoxicity at given experimental condition. Further, the results of LDH and NO release supported the cytotoxic nature of the complexes. The observed cytotoxicity of the complexes may be routed through ROS-hypergeneration and lipid-peroxidation with subsequent depletion of cellular antioxidant pool (GSH, SOD, CAT, GPx and GST) resulted in the reduction of mitochondrial-membrane potential, caspase-3 activation and DNA fragmentation. Thus, the data from the present study disclose that the complexes could induce apoptosis in A549 cells through mitochondrial mediated fashion and inhibited the migration of lung cancer cells and by metastasis. PMID:24946146

  1. Synthesis, spectral characterization, molecular modeling, thermal study and biological evaluation of transition metal complexes of a bidentate Schiff base ligand

    NASA Astrophysics Data System (ADS)

    Chandra, Sulekh; Bargujar, Savita; Nirwal, Rita; Qanungo, Kushal; Sharma, Saroj K.

    2013-09-01

    Complexes of copper(II) and nickel(II) of general composition M(L)2X2, have been synthesized [where L = 3-Bromoacetophenone thiosemicarbazone and X = CH3COO-, Cl- and NO3-]. All the complexes were characterized by elemental analysis, magnetic moments, IR, electronic and EPR spectral studies. The ligand behaved as bidentate and coordinated through sulfur of sbnd Cdbnd S group and nitrogen atoms of sbnd Cdbnd N group. The copper(II) and nickel(II) complexes were found to have magnetic moments 1.94-2.02 BM, 2.96-3.02 BM respectively which was corresponding to one and two unpaired electrons respectively. The molar conductance of the complexes in solution of DMSO lies in the range of 10-20 Ω-1 cm2 mol-1 indicating their non-electrolytic behavior. On the basis of EPR, electronic and infrared spectral studies, tetragonal geometry has been assigned for copper(II) complexes and an octahedral geometry for nickel(II) complexes. The values of Nephelauxetic parameter β lie in the range 0.19-0.37 which indicated the covalent character in metal ligand ‘σ' bond. Synthesized ligand and its copper(II) and nickel(II) complexes have also been screened against different bacterial and fungal species which suggested that complexes are more active than the ligands in antimicrobial activities.

  2. Membrane interactions and conformational preferences of human and avian prion N-terminal tandem repeats: the role of copper(II) ions, pH, and membrane mimicking environments.

    PubMed

    Di Natale, Giuseppe; Pappalardo, Giuseppe; Milardi, Danilo; Sciacca, Michele F M; Attanasio, Francesco; La Mendola, Diego; Rizzarelli, Enrico

    2010-11-01

    The flexible N-terminal domain of the prion protein (PrP(c)) is believed to play a pivotal role in both trafficking of the protein through the cell membrane and its pathogenic conversion into the β sheet-rich scrapie isoform (PrP(sc)). Unlike mammalian PrP(c), avian prion proteins are not known to undergo any pathogenic conformational conversions. Consequently, some critical advances in our understanding of the molecular mechanisms underlying prion pathogenesis are expected from comparative studies of the biophysical properties of the N-terminal domains of the two proteins. The present study addresses the role played by different environmental factors, i.e., copper(II), pH, and membrane-mimicking environments, in assisting the conformational preferences of huPrP60-91 and chPrP53-76, two soluble peptides encompassing the N-terminal copper(II) binding domains of the human and chicken prion proteins, respectively. Moreover, the membrane interactions of huPrP60-91, chPrP53-76, and their copper(II) complexes were evaluated by Trp fluorescence in conjunction with measurements of the variation in thermotropic properties of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) unilamellar vesicles. Circular dichroism experiments revealed that huPrP60-91 adopts a predominant polyproline II conformation in aqueous solution that is destabilized at basic pH or in the presence of trifluoroethanol (TFE). Unlike anionic sodium dodecyl sulfate (SDS), which seems to stabilize the polyproline II conformation further, zwitterionic dodecylphosphocholine (DPC) micelles do not affect the peptide structure. On the contrary, copper(II) promptly promotes an increase in β-turn-rich structures. Differential scanning calorimetry (DSC) and Trp fluorescence assays carried out on DPPC model membranes after incubation with huPrP60-91 showed a marked tendency of the peptide to slowly penetrate the lipid bilayer with a concomitant conformational transition toward an extended β-sheet-like structure

  3. Optically active red-emitting Cu nanoclusters originating from complexation and redox reaction between copper(ii) and d/l-penicillamine

    NASA Astrophysics Data System (ADS)

    Long, Tengfei; Guo, Yanjia; Lin, Min; Yuan, Mengke; Liu, Zhongde; Huang, Chengzhi

    2016-05-01

    Despite a significant surge in the number of investigations into both optically active Au and Ag nanostructures, there is currently only limited knowledge about optically active Cu nanoclusters (CuNCs) and their potential applications. Here, we have succeeded in preparing a pair of optically active red-emitting CuNCs on the basis of complexation and redox reaction between copper(ii) and penicillamine (Pen) enantiomers, in which Pen serves as both a reducing agent and a stabilizing ligand. Significantly, the CuNCs feature unique aggregation induced emission (AIE) characteristics and therefore can serve as pH stimuli-responsive functional materials. Impressively, the ligand chirality plays a dramatic role for the creation of brightly emissive CuNCs, attributed to the conformation of racemic Pen being unfavorable for the electrostatic interaction, and thus suppressing the formation of cluster aggregates. In addition, the clusters display potential toward cytoplasmic staining and labelling due to the high photoluminescence (PL) quantum yields (QYs) and remarkable cellular uptake, in spite that no chirality-dependent effects in autophagy and subcellular localization are observed in the application of chiral cluster enantiomer-based cell imaging.Despite a significant surge in the number of investigations into both optically active Au and Ag nanostructures, there is currently only limited knowledge about optically active Cu nanoclusters (CuNCs) and their potential applications. Here, we have succeeded in preparing a pair of optically active red-emitting CuNCs on the basis of complexation and redox reaction between copper(ii) and penicillamine (Pen) enantiomers, in which Pen serves as both a reducing agent and a stabilizing ligand. Significantly, the CuNCs feature unique aggregation induced emission (AIE) characteristics and therefore can serve as pH stimuli-responsive functional materials. Impressively, the ligand chirality plays a dramatic role for the creation of

  4. Copper(II) Coordination Polymers Self-Assembled from Aminoalcohols and Pyromellitic Acid: Highly Active Precatalysts for the Mild Water-Promoted Oxidation of Alkanes.

    PubMed

    Fernandes, Tiago A; Santos, Carla I M; André, Vânia; Kłak, Julia; Kirillova, Marina V; Kirillov, Alexander M

    2016-01-01

    Three novel water-soluble 2D copper(II) coordination polymers-[{Cu2(μ2-dmea)2(H2O)}2(μ4-pma)]n·4nH2O (1), [{Cu2(μ2-Hedea)2}2(μ4-pma)]n·4nH2O (2), and [{Cu(bea)(Hbea)}4(μ4-pma)]n·2nH2O (3)-were generated by an aqueous medium self-assembly method from copper(II) nitrate, pyromellitic acid (H4pma), and different aminoalcohols [N,N-dimethylethanolamine (Hdmea), N-ethyldiethanolamine (H2edea), and N-benzylethanolamine (Hbea)]. Compounds 2 and 3 represent the first coordination polymers derived from H2edea and Hbea. All the products were characterized by infrared (IR), electron paramagnetic resonance (EPR), and ultraviolet-visible light (UV-vis) spectroscopy, electrospray ionization-mass spectroscopy (ESI-MS(±)), thermogravimetric and elemental analysis, and single-crystal X-ray diffraction (XRD), which revealed that their two-dimensional (2D) metal-organic networks are composed of distinct dicopper(II) or monocopper(II) aminoalcoholate units and μ4-pyromellitate spacers. From the topological viewpoint, the underlying 2D nets of 1-3 can be classified as uninodal 4-connected layers with the sql topology. The structures of 1 and 2 are further extended by multiple intermolecular hydrogen bonds, resulting in three-dimensional (3D) hydrogen-bonded networks with rare or unique topologies. The obtained compounds also act as highly efficient precatalysts for the mild homogeneous oxidation, by aqueous H2O2 in acidic MeCN/H2O medium, of various cycloalkanes to the corresponding alcohols and ketones. Overall product yields up to 45% (based on cycloalkane) were attained and the effects of various reaction parameters were investigated, including the type of precatalyst and acid promoter, influence of water, and substrate scope. Although water usually strongly inhibits the alkane oxidations, a very pronounced promoting behavior of H2O was detected when using the precatalyst 1, resulting in a 15-fold growth of an initial reaction rate in the cyclohexane oxidation on

  5. Solvent-controlled synthesis of tetranuclear cage-like copper(II) silsesquioxanes. Remarkable features of the cage structures and their high catalytic activity in oxidation with peroxides.

    PubMed

    Dronova, Marina S; Bilyachenko, Alexey N; Yalymov, Alexey I; Kozlov, Yuriy N; Shul'pina, Lidia S; Korlyukov, Alexander A; Arkhipov, Dmitry E; Levitsky, Mikhail M; Shubina, Elena S; Shul'pin, Georgiy B

    2014-01-14

    Two principally different in their molecular architecture isomeric tetranuclear copper(ii) silsesquioxanes, "Globule"-like compound [(PhSiO1.5)12(CuO)4(NaO0.5)4] (1) and "Sandwich"-like derivative [(PhSiO1.5)6(CuO)4(NaO0.5)4(PhSiO1.5)6] (2), were synthesized by the partial cleavage of polymeric copper(ii) silsesquioxane [(PhSiO1.5)2(CuO)]n by tetraphenylcyclotetrasiloxanolate. The route leading to the formation of either 1 or 2 entirely depends on the nature and composition of the solvent used for this reaction. Thus, the process in an ethanol-1-butanol solution gives compound 1. When a 1,4-dioxane-methanol mixture was used, compound 2 was prepared. The structures and unusual crystal packing of the cages were confirmed by the X-ray studies. It has been found that the reaction of benzene with H2O2 in acetonitrile solution at 50 °C catalyzed by 1 requires addition of trifluoroacetic acid (TFA) in low concentration and gives phenol with a turnover number (TON) of 250 after 3 h. The initial reaction rate W0 linearly depends on the concentration of catalyst 2. The oxidation of 1-phenylethanol to acetophenone with hydrogen peroxide catalyzed by complex 1 in the presence of TFA is not efficient. In contrast, 1 exhibited excellent activity in the oxidation with tert-butyl hydroperoxide (TBHP) in the absence of any acid (the yield of acetophenone was close to the quantitative, TON attained 475 after 2 h). A kinetic study of this reaction led to the conclusion that the process occurs with the participation of radicals tert-BuO˙ produced in the Cu-promoted decomposition of TBHP. The mode of dependence of W0 on the initial concentration of TBHP indicates the formation of an intermediate adduct between the catalyst 1 and TBHP (characterized by the equilibrium constant K1≈ 2 M(-1) for the conditions of conducted experiments) followed by subsequent decomposition of the adduct (k2≈ 0.2 s(-1)) to generate an intermediate species tert-BuO˙ which induces the alcohol oxidation

  6. Mixed-ligand copper(ii) Schiff base complexes: the role of the co-ligand in DNA binding, DNA cleavage, protein binding and cytotoxicity.

    PubMed

    Lian, Wen-Jing; Wang, Xin-Tian; Xie, Cheng-Zhi; Tian, He; Song, Xue-Qing; Pan, He-Ting; Qiao, Xin; Xu, Jing-Yuan

    2016-05-31

    Four novel mononuclear Schiff base copper(ii) complexes, namely, [Cu(L)(OAc)]·H2O (), [Cu(HL)(C2O4)(EtOH)]·EtOH (), [Cu(L)(Bza)] () and [Cu(L)(Sal)] () (HL = 1-(((2-((2-hydroxypropyl)amino)ethyl)imino)methyl)naphthalene-2-ol), Bza = benzoic acid, Sal = salicylic acid), were synthesized and characterized by X-ray crystallography, elemental analysis and infrared spectroscopy. Single-crystal diffraction analysis revealed that all the complexes were mononuclear molecules, in which the Schiff base ligand exhibited different coordination modes and conformations. The N-HO and O-HO inter- and intramolecular hydrogen bonding interactions linked these molecules into multidimensional networks. Their interactions with calf thymus DNA (CT-DNA) were investigated by UV-visible and fluorescence spectrometry, as well as by viscosity measurements. The magnitude of the Kapp values of the four complexes was 10(5), indicating a moderate intercalative binding mode between the complexes and DNA. Electrophoresis results showed that all these complexes induced double strand breaks of pUC19 plasmid DNA in the presence of H2O2 through an oxidative pathway. In addition, the fluorescence spectrum of human serum albumin (HSA) with the complexes suggested that the quenching mechanism of HSA by the complexes was a static process. Moreover, the antiproliferative activity of the four complexes against HeLa (human cervical carcinoma) and HepG-2 (human liver hepatocellular carcinoma) cells evaluated by colorimetric cell proliferation assay and clonogenic assay revealed that all four complexes had improved cytotoxicity against cancer cells. Inspiringly, complex , with salicylic acid as the auxiliary ligand, displayed a stronger anticancer activity, suggesting that a synergistic effect of the Schiff base complex and the nonsteroidal anti-inflammatory drug may be involved in the cell killing process. The biological features of mixed-ligand copper(ii) Schiff base complexes and how acetic auxiliary

  7. Dimensional modulation and magnetic properties of triazole- and bis(triazole)-based copper(II) coordination polymers tuned by aromatic polycarboxylates

    SciTech Connect

    Zhang, Ju-Wen; Zhao, Wei; Lu, Qi-Lin; Luan, Jian; Qu, Yun; Wang, Xiu-Li

    2014-04-01

    Five new metal–organic coordination polymers ([Cu{sub 3}(μ{sub 2}-OH){sub 2}(atrz){sub 2}(nph){sub 2}(H{sub 2}O){sub 2}]·2H{sub 2}O){sub n} (1), ([Cu{sub 2}(μ{sub 3}-OH)(atrz)(1,2,4-btc)]·2H{sub 2}O){sub n} (2), ([Cu{sub 2}(μ{sub 3}-OH)(atrz)(1,2,4-btc)(H{sub 2}O)]·H{sub 2}O){sub n} (3), [Cu(dth){sub 0.5}(nph)(H{sub 2}O)]{sub n} (4) and [Cu(dth)(Hnip){sub 2}]{sub n} (5) [atrz=4-amino-1,2,4-triazole, dth=N,N'-di(4H-1,2,4-triazole)hexanamide, H{sub 2}nph=3-nitrophthalic acid, 1,2,4-H{sub 3}btc=1,2,4-benzenetricarboxylic acid and H{sub 2}nip=5-nitroisophthalic acid] were hydrothermally synthesized and structurally characterized. Polymer 1 shows a one-dimensional (1D) chain. Polymers 2 and 3 exhibit similar tetranuclear Cu{sup II}{sub 4} cluster-based three-dimensional (3D) frameworks with the same components. Polymer 4 possesses a 3D framework with a 4{sup 12}·6{sup 3}-pcu topology. Polymer 5 displays a 3D framework with a 4{sup 4}·6{sup 10}·8-mab topology. The magnetic properties of 1–4 were investigated. - Graphical abstract: Five triazole-based copper(II) polymers modulated by polycarboxylates were synthesized. Bis-triazole-bis-amide ligand and polycarboxylates play important roles in tuning dimensionality of polymers. Magnetic properties of polymers were investigated. - Highlights: • Five triazole- and bis(triazole)-based copper(II) coordination polymers tuned by aromatic polycarboxylates were obtained. • The aromatic polycarboxylates have an important influence on the dimensionality of five polymers. • The magnetic properties of four polymers were investigated.

  8. Crystallographic, Electrochemical, and Pulsed EPR Study of Copper(II) Polyimidazole Complexes Relevant to the Metal Sites of Copper Proteins(,).

    PubMed

    Place, Christophe; Zimmermann, Jean-Luc; Mulliez, Etienne; Guillot, Geneviève; Bois, Claudette; Chottard, Jean-Claude

    1998-08-10

    Copper(II) complexes of the following polyimidazole ligands have been synthesized: bis(imidazol-2-yl)methane (BIM), bis(imidazol-2-yl) ketone (BIK), 4-(imidazol-4-ylmethyl)-2-(imidazol-2-ylmethyl)imidazole (TRIM), bis[4-(imidazol-4-ylmethyl)imidazol-2-yl]methane (TIM), and bis[4-(imidazol-4-ylmethyl)imidazol-2-yl] ketone (TIK). Their crystal structures have been determined using X-ray diffraction. [Cu(ClO(4))(2)(BIM)(2)], 1, belongs to the triclinic space group P&onemacr; system, a = 7.161(4) Å, b = 7.986(6) Å, c = 9.865(3) Å, alpha = 76.73(5) degrees, beta = 71.18(3) degrees, gamma = 76.44(5) degrees, Z = 1, T = 291 K; R = 0.035, R(w) = 0.036 for 1668 reflections; Cu-N = 1.998(3) and 2.001(2) Å, Cu-O = 2.574(4) Å, in a tetragonal geometry. [Cu(BIK)(2)](ClO(4))(2), 2, belongs to the monoclinic space group C2/c system, a = 9.029(3) Å, b = 12.497(2)Å, c = 19.197(2) Å, beta = 94.59(2) degrees, Z = 4, T = 291 K; R = 0.056, R(w) = 0.061 for 1052 reflections; Cu-N = 1.961(7) and 1.954(7) Å, in a distorted tetrahedral geometry. [CuCl(TRIM)(CH(3)OH)]Cl, 6, belongs to the monoclinic space group P2(1)/n system, a = 14.192(5) Å, b = 13.832(5) Å, c = 7.913(3) Å, beta = 90.55(4) degrees, Z = 4, T = 291 K; R = 0.062, R(w) = 0.057 for 1377 reflections; Cu-N = 1.987(7), 2.007(7) and 2.007(6) Å, Cu-O = 2.521(7) Å, Cu-Cl = 2.298(2) Å, in a square pyramidal geometry. [Cu(ClO(4))(TIM)](ClO(4)), 4, belongs to the triclinic space group P&onemacr; system, a = 9.604(4) Å, b = 11.508(6) Å, c = 12.003(8) Å, alpha = 58.79(4) degrees, beta = 94.59(2) degrees, gamma = 67.43(3) degrees, Z = 2, T = 291 K; R = 0.057, R(w) = 0.062 for 2084 reflections; Cu-N = 1.985(7), 1.964(7), 1.967(7), and 1.966(7) Å, Cu-O = 2.553(8) Å, in a distorted square pyramidal geometry. [CuCl(TIK)](ClO(4)), 7, belongs to the triclinic space group P&onemacr; system, a = 7.432(3) Å, b = 12.573(3) Å, c = 12.945(2) Å, alpha = 114.94(4) degrees, beta = 92.46(2) degrees, gamma = 103.49(3) degrees, Z = 2

  9. Studies on 2H NMR and single crystal X-ray diffraction of thermochromic bis ( N, N-diethyl-1,2-ethanediamine) nickel(II) complexes with and without structural phase transitions

    NASA Astrophysics Data System (ADS)

    Ikeda, Ryuichi; Kotani, Kyoko; Ohki, Hiroshi; Ishimaru, Shin'ichi; Okamoto, Ken-Ichi; Ghosh, Ashutosh

    1995-02-01

    The thermochromic complex bis( N, N-diethyl-1,2-ethanediamine) ((C 2H 5) 2NC 2H 4NH 2) nickel(II) perchlorate([Ni(dieten) 2](ClO 4) 2) was studied by single crystal X-ray diffraction and found to form a triclinic lattice with space group P 1¯, a = 8.108(1) Å, b = 8.835(1) Å, c = 9.736(1) Å, α = 94.24(1)°, β = 114.28(1)°, γ = 116.49(1)°, and Z = 1 being isomorphous with that of [Cu(dieten) 2](ClO 4) 2 which has been reported to have a thermochromic phase transition. The temperature dependences of 2H NMR spectra in [Ni(dieten- d2) 2]X 2 (dieten- d2: (C 2H 5) 2NC 2H 4ND 2; X: ClO 4, BF 4, Br, NO 3, I) were observed and quadrupole coupling constants e2Qq and asymmetry parameters η were evaluated. Below room temperature, an almost rigid structure of the ND 2 group was derived by analyzing the spectra. For perchlorate and tetrafluoroborate with colour changes at respective phase transition temperatures ( Tc), quadrupole parameters were also changed discontinuously at Tc. The analysis of spectra observed above Tc afforded two-site jumps of the N-D bond by angles of 52-55° supporting the ring-puckering model of the five-membered chelate ring. However, iodide having no phase transition showed continuous changes of both e2Qq and η values with increasing temperature up to 450 K. These results which cannot be attributed to the puckering motion were explained by whole complex reorientation. These molecular motions are discussed in connection with the colour change observed in these complexes.

  10. Existence of a low isoenantioselective temperature in complexation gas chromatography. Profound change of enantioselectivity of a nickel(II) chiral selector either bonded to, or dissolved in, poly(dimethylsiloxane).

    PubMed

    Jiang, Zhengjin; Schurig, Volker

    2008-04-01

    The gas chromatographic enantiorecognition of the two enantiomeric pairs of Z- and E-2-ethyl-dioxaspiro[4,4]nonane (chalcogran), respectively, critically depends on whether the chiral selector nickel(II) bis[3-(heptafluorobutanoyl)-(1R)-camphorate] is chemically linked via a methylene spacer to poly(dimethylsiloxane) (Chirasil-Nickel 1), or is only dissolved in poly(dimethylsiloxane) (Chira-Nickel 2a). On 2a, the enantiomers are separated at ambient temperature with a large apparent enantioseparation factor alpha(app) whereas on Chirasil-Nickel 1 only a low alpha(app) is observed whereby the elution order of the enantiomers is reversed. Concise temperature-dependent studies show that on Chirasil-Nickel 1 a low isoenantioselective temperature, T(isoenant), of 80 degrees C is experimentally observed as the result of enthalpy/entropy compensation. For thermodynamic measurements, the method of the retention-increment R' has been employed. This concept separates achiral contributions to retention due to the poly(dimethylsiloxane) matrix, which are identical for enantiomers, from enantioselective contributions to retention, which are due to complexation of enantiomers with the chiral selector. From Van't Hoff plots, concise thermodynamic data of enantioselectivity, -Delta(D),(L)(DeltaG), -Delta(D,L)(DeltaH), Delta(D,L)(DeltaS) and T(isoenant) were obtained. It was found that minute changes in the structure of the spiroketals as well as miniscule differences of the nature of the chiral selector present in the stationary phase (chemically bonded versus physically dissolved) led to profound differences in enantioselectivity. The observation of a low isoenantioselective temperature T(isoenant) represents are rare phenomenon in enantioselective gas chromatography which both complicates the study of chiral recognition mechanisms and the correlation of the absolute configuration and retention due to the temperature-dependent reversal of the elution order. PMID:17888444

  11. Cocrystallization of photosensitive energetic copper(II) perchlorate complexes with the nitrogen-rich ligand 1,2-Di(1H-tetrazol-5-yl)ethane.

    PubMed

    Evers, Jürgen; Gospodinov, Ivan; Joas, Manuel; Klapötke, Thomas M; Stierstorfer, Jörg

    2014-11-01

    Two recently introduced concepts in the design of new energetic materials, namely complexation and cocrystallization, have been applied in the synthesis and characterization of the energetic copper(II) compound "[Cu(dt-5-e)2(H2O)](ClO4)2," which consists of two different complex cations and can be described as a model energetic ionic cocrystal. The presence of both the N-rich 1,2-di(1H-tetrazol-5-yl)ethane ligand and oxidizing perchlorate counterion results in a new type of energetic material. The ionic complex cocrystal consists of a mononuclear and a trinuclear complex unit. It can be obtained by precipitation from perchloric acid or by dehydration of the related mononuclear coordination compound [Cu(dt-5-e)2(H2O)2](ClO4)2·2H2O at 70 °C in the solid state. The transformation starting at 60 °C was monitored by X-ray powder diffraction and thermal analysis. The energetic ionic cocrystal was shown to be a new primary explosive suitable for laser ignition. The different coordination spheres within the ionic cocrystal (octahedral and square pyramidal) were shown by UV/vis/NIR spectroscopy to result in excellent light absorption. PMID:25310513

  12. The interaction of taurine-salicylaldehyde Schiff base copper(II) complex with DNA and the determination of DNA using the complex as a fluorescence probe

    NASA Astrophysics Data System (ADS)

    Zhang, Xiaoyan; Wang, Yong; Zhang, Qianru; Yang, Zhousheng

    2010-09-01

    The interaction of taurine-salicylaldehyde Schiff base copper(II) (Cu(TSSB) 22+) complex with DNA was explored by using UV-vis, fluorescence spectrophotometry, and voltammetry. In pH 7.4 Tris-HCl buffer solution, the binding constant of the Cu(TSSB) 22+ complex interaction with DNA was 3.49 × 10 4 L mol -1. Moreover, due to the fluorescence enhancing of Cu(TSSB) 22+ complex in the presence of DNA, a method for determination of DNA with Cu(TSSB) 22+ complex as a fluorescence probe was developed. The fluorescence spectra indicated that the maximum excitation and emission wavelength were 389 nm and 512 nm, respectively. Under optimal conditions, the calibration graphs are linear over the range of 0.03-9.03 μg mL -1 for calf thymus DNA (CT-DNA), 0.10-36 μg mL -1 for yeast DNA and 0.01-10.01 μg mL -1 for salmon DNA (SM-DNA), respectively. The corresponding detection limits are 7 ng mL -1 for CT-DNA, 3 ng mL -1 for yeast DNA and 3 ng mL -1 for SM-DNA. Using this method, DNA in synthetic samples was determined with satisfactory results.

  13. Hydrated and anhydrous forms of copper(II) complex of 3-methylpicolinic acid, and spectroscopic studies of their ROS-inducing and proteasome inhibition

    NASA Astrophysics Data System (ADS)

    Lai, Jing Wei; Chan, Cheang Wei; Ng, Chew Hee; Ooi, Ing Hong; Tan, Kong Wai; Maah, Mohd Jamil; Ng, Seik Weng

    2016-02-01

    The hydrated and anhydrous forms of the copper(II) complex of 3-methylpicolinic acid, monomeric [Cu(3Me-pic)2(H2O)]·H2O 1 and polymeric [Cu(3Me-pic)2]n2, were synthesized and characterized by FTIR, UV-visible spectroscopy, conductivity measurement, magnetic susceptibility determination, electron paramagnetic resonance (EPR) and light scattering. Crystal structure analysis of 2 shows that it has a doubly-bridged polymeric structure, involving diagonally stacked Cu(3Me-pic)2 units which are linked via carbonyl oxygen atoms of the 3Me-pic moieties. Analysis of EPR spectra at 133 K and 293 K suggests isotropic intermolecular spin interaction only in 2. Complex 2 dissolved in DMF and DMSO solvents to yield nano-size particles. Solution studies show aqueous solutions of 1 and 2 contain the same neutral Cu(3Me-pic)2 species, which generates less hydroxyl radicals from the reaction with hydrogen peroxide than their precursor CuCl2. The Cu(3Me-pic)2 species exhibit more selective inhibition of the β2 site of the 20S proteasome, among the three proteolytic sites.

  14. Biologically active Schiff bases containing thiophene/furan ring and their copper(II) complexes: Synthesis, spectral, nonlinear optical and density functional studies

    NASA Astrophysics Data System (ADS)

    Gündüzalp, Ayla Balaban; Özsen, İffet; Alyar, Hamit; Alyar, Saliha; Özbek, Neslihan

    2016-09-01

    Schiff bases; 1,8-bis(thiophene-2-carboxaldimine)-p-menthane (L1) and 1,8-bis(furan-2-carboxaldimine)-p-menthane (L2) have been synthesized and characterized by elemental analysis, 1Hsbnd 13C NMR, UV-vis, FT-IR and LC-MS methods. 1H and 13C shielding tensors for L1 and L2 were calculated with GIAO/DFT/B3LYP/6-311++G(d,p) methods in CDCl3. The vibrational band assignments, nonlinear optical (NLO) activities, frontier molecular orbitals (FMOs) and absorption spectrum have been investigated by the same basis set. Schiff base-copper(II) complexes have been synthesized and structurally characterized with spectroscopic methods, magnetic and conductivity measurements. The spectroscopic data suggest that Schiff base ligands coordinate through azomethine-N and thiophene-S/furan-O donors (as SNNS and ONNO chelating systems) to give a tetragonal geometry around the copper(II) ions. Schiff bases and Cu(II) complexes have been screened for their biological activities on different species of pathogenic bacteria, those are, Gram positive bacteria: Bacillus subtitilus, Yersinia enterotica, Bacillus cereus, Listeria monocytogenes, Micrococcus luteus and Gram negative bacteria: Escherichia coli, Pseudomonas aeroginosa, Shigella dysenteriae, Salmonella typhi, Klebsiella pseudomonas by using microdilution technique (MIC values in mM). Biological activity results show that Cu(II) complexes have higher activities than parent ligands and metal chelation may affect significantly the antibacterial behavior of the organic ligands.

  15. Hemin/G-quadruplex-based DNAzyme concatamers for in situ amplified impedimetric sensing of copper(II) ion coupling with DNAzyme-catalyzed precipitation strategy.

    PubMed

    Xu, Mingdi; Gao, Zhuangqiang; Wei, Qiaohua; Chen, Guonan; Tang, Dianping

    2015-12-15

    A new signal-amplification strategy based on copper(II) (Cu(2+))-dependent DNAzyme was developed for sensitive impedimetric biosensing of Cu(2+) in aqueous solution by coupling with target-induced formation of hemin/G-quadruplex-based DNAzyme and enzymatic catalytic precipitation technique. Initially, the target analyte cleaved the Cu(2+)-specific DNAzyme to generate an initiator strand on the sensor. Thereafter, the initiator strand underwent an unbiased strand-displacement reaction between hairpin probes in turn to construct a nicked double-helix, accompanying the formation of hemin/G-quadruplex DNAzyme on the long duplex DNA. The newly formed DNAzyme could oxidize the 4-chloro-1-naphthol (4-CN) to produce an insoluble precipitation on the sensor, thus resulting in a local alteration of the conductivity. Under the optimal conditions, the resistance increased with the increasing Cu(2+) in the sample, and exhibited a wide dynamic working range from 0.1 pM to 5.0 nM with a detection limit of 60 fM. The methodology also displayed a high selectivity for Cu(2+) relative to other potentially interfering ions owing to the highly specific Cu(2+)-dependent DNAzyme, and was applicable for monitoring Cu(2+) in real river samples. Thus, our strategy has a good potential in the environment surveys. PMID:26093122

  16. Coordination Reactions and Noncovalent Interactions of Polyamines with Nucleotides in Binary Systems and with Nucleotides and Copper(II) Ion in Ternary Systems

    PubMed Central

    Lomozik, Lechoslaw; Gasowska, Anna; Krzysko, Grzegorz; Bregier-Jarzebowska, Romualda

    2010-01-01

    Interactions of nucleotides (AMP, CMP) and 1,2-diaminopropane (tn-1) or 2-methyl-1,2-diaminopropane (tn-2) in metal-free systems as well as in the systems including copper(II) ions were studied. The composition and overall stability constants of the complexes formed were determined by the potentiometric method, whereas the interaction centres and coordination sites were identified by spectroscopic methods. It was found that phosphate groups of nucleotides and the protonated amine groups of polyamines are the centres of interaction. The differences in the interactions with the polyamines which act as models of biogenic amines are impacted by the presence of lateral chains (methylene groups) in tn-1 and tn-2. In the ternary systems with Cu(II) ions, the heteroligand complexes are mainly of the ML⋯L' type, in which the protonated polyamine is engaged in noncovalent interactions with the anchoring Cu(II)-nucleotide complex. The complexes formed in the Cu/NMP)/tn-1 system are more stable than those formed in the system with tn-2. The mode of coordination in the complex is realised mainly through the phosphate groups of the nucleotide with involvement of the endocyclic nitrogen atoms in a manner which depends upon the steric conditions and in particular on the number of the methylene groups in the polyamine molecule. PMID:20885917

  17. Diacetylbis(N(4)-methylthiosemicarbazonato) Copper(II) (CuII(atsm)) Protects against Peroxynitrite-induced Nitrosative Damage and Prolongs Survival in Amyotrophic Lateral Sclerosis Mouse Model*

    PubMed Central

    Soon, Cynthia P. W.; Donnelly, Paul S.; Turner, Bradley J.; Hung, Lin W.; Crouch, Peter J.; Sherratt, Nicki A.; Tan, Jiang-Li; Lim, Nastasia K.-H.; Lam, Linh; Bica, Laura; Lim, SinChun; Hickey, James L.; Morizzi, Julia; Powell, Andrew; Finkelstein, David I.; Culvenor, Janetta G.; Masters, Colin L.; Duce, James; White, Anthony R.; Barnham, Kevin J.; Li, Qiao-Xin

    2011-01-01

    Amyotrophic lateral sclerosis (ALS) is a progressive paralyzing disease characterized by tissue oxidative damage and motor neuron degeneration. This study investigated the in vivo effect of diacetylbis(N(4)-methylthiosemicarbazonato) copper(II) (CuII(atsm)), which is an orally bioavailable, blood-brain barrier-permeable complex. In vitro the compound inhibits the action of peroxynitrite on Cu,Zn-superoxide dismutase (SOD1) and subsequent nitration of cellular proteins. Oral treatment of transgenic SOD1G93A mice with CuII(atsm) at presymptomatic and symptomatic ages was performed. The mice were examined for improvement in lifespan and motor function, as well as histological and biochemical changes to key disease markers. Systemic treatment of SOD1G93A mice significantly delayed onset of paralysis and prolonged lifespan, even when administered to symptomatic animals. Consistent with the properties of this compound, treated mice had reduced protein nitration and carbonylation, as well as increased antioxidant activity in spinal cord. Treatment also significantly preserved motor neurons and attenuated astrocyte and microglial activation in mice. Furthermore, CuII(atsm) prevented the accumulation of abnormally phosphorylated and fragmented TAR DNA-binding protein-43 (TDP-43) in spinal cord, a protein pivotal to the development of ALS. CuII(atsm) therefore represents a potential new class of neuroprotective agents targeting multiple major disease pathways of motor neurons with therapeutic potential for ALS. PMID:22033929

  18. Binary and ternary copper(II) complexes of a tridentate ONS ligand derived from 2-aminochromone-3 carboxaldehyde and thiosemicarbazide: Synthesis, spectral studies and antimicrobial activity

    NASA Astrophysics Data System (ADS)

    Shebl, Magdy; Ibrahim, M. A.; Khalil, Saied M. E.; Stefan, S. L.; Habib, H.

    2013-11-01

    A tridentate ONS donor ligand, HL, was synthesized by the condensation of 2-aminochromone-3-carboxaldehyde with thiosemicarbazide. The structure of the ligand was elucidated by elemental analyses, IR, 1H and 13C NMR, electronic and mass spectra. Reaction of the ligand with several copper(II) salts, including AcO-, NO3-, SO42-, Cl-, Br- and ClO4- afforded different metal complexes that reflect the non-coordinating or weakly coordinating power of the ClO4- and Br- anions as compared to the strongly coordinating power of AcO-, SO42-, Cl- and NO3- anions. Also, the ligand was allowed to react with Cu(II) ion in the presence of a secondary ligand (L‧) [N,O-donor; 8-hydroxyquinoline or N,N-donor; 1,10-phenanthroline]. Characterization and structure elucidation of the prepared complexes were achieved by elemental and thermal analyses, IR, electronic, mass and EPR spectra as well as conductivity and magnetic susceptibility measurements. The EPR spin Hamiltonian parameters of some complexes were calculated. The metal complexes exhibited octahedral and square planar geometrical arrangements depending on the nature of the anion. The ligand and most of its metal complexes showed antibacterial activity towards Gram-positive bacteria (Staphylococcus aureus and Bacillus subtilis), Gram-negative bacteria (Salmonella typhimurium and Escherichia coli), yeast (Candida albicans) and fungus (Aspergillus fumigatus).

  19. Solvent exchange and discrimination in crystalline state. Formation and properties of copper(II) complexes containing 2,3-bis(isonicotinoyloxy)naphthalene

    NASA Astrophysics Data System (ADS)

    Cho, Yoonjung; Kim, Jeong Gyun; Noh, Tae Hwan; Jung, Ok-Sang

    2013-09-01

    Self-assembly of copper(II) nitrate with 2,3-bis(isonicotinoyloxy)naphthalene (L) in a mixture of acetonitrile and dichloromethane produces a 30-membered discrete metallacyclodimer, [Cu(NO3)2(L)]2, while the self-assembly in a mixture of N,N-dimethylformamide and CH2Cl2 and a mixture of N,N-dimethylformamide and dioxane yields 1D coordination polymers consisting of [Cu(NO3)2(L)2]ṡ4CH2Cl2 and [Cu(NO3)2(L)2]ṡ3dioxane, respectively. Recrystallizations of [Cu(NO3)2(L)]2 from N,N-dimethylformamide/CH2Cl2 and N,N-dimethylformamide/dioxane lead to [Cu(NO3)2(L)2]ṡ4CH2Cl2 and [Cu(NO3)2(L)2]ṡ3dioxane, respectively. Constructions of the two skeletons, metallacyclodimer and 1D coordination polymer, are determined by solvents rather than synthetic methodologies. For [Cu(NO3)2(L)2]ṡ4CH2Cl2 and [Cu(NO3)2(L)2]ṡ3dioxane, exchange of the solvate molecules in the crystalline solids is carried out, and the 1D skeletal structure discriminates dioxane and CH2Cl2 molecules.

  20. Hydrolysis mechanisms of BNPP mediated by facial copper(II) complexes bearing single alkyl guanidine pendants: cooperation between the metal centers and the guanidine pendants.

    PubMed

    Zhang, Xuepeng; Liu, Xueping; Phillips, David Lee; Zhao, Cunyuan

    2016-01-28

    The hydrolysis mechanisms of DNA dinucleotide analogue BNPP(-) (bis(p-nitrophenyl) phosphate) catalyzed by mononuclear/dinuclear facial copper(ii) complexes bearing single alkyl guanidine pendants were investigated using density functional theory (DFT) calculations. Active catalyst forms have been investigated and four different reaction modes are proposed accordingly. The [Cu2(L(1))2(μ-OH)](3+) (L(1) is 1-(2-guanidinoethyl)-1,4,7-triazacyclononane) complex features a strong μ-hydroxo mediated antiferromagnetic coupling between the bimetallic centers and the corresponding more stable open-shell singlet state. Three different reaction modes involving two catalysts and a substrate were proposed for L(1) entries and the mode 1 in which an inter-complex nucleophilic attack by a metal bound hydroxide was found to be more favorable. In the L(3)-involved reactions (L(3) is 1-(4-guanidinobutyl)-1,4,7-triazacyclononane), the reaction mode in which an in-plane intracomplex scissoring-like nucleophilic attack by a Cu(ii)-bound hydroxide was found to be more competitive. The protonated guanidine pendants in each proposed mechanism were found to play crucial roles in stabilizing the reaction structures via hydrogen bonds and in facilitating the departure of the leaving group via electrostatic attraction. The calculated results are consistent with the experimental observations that the Cu(ii)-L(3) complexes are hydrolytically more favorable than their L(1)-involved counterparts. PMID:26688285

  1. Infrared spectrum, DFT: pBP86/DN** and NCA vibrational calculations of 2-methylthiosemicarbazide copper(II) nitrate [Cu(2MeTSC) 2(NO 3) 2

    NASA Astrophysics Data System (ADS)

    Ramos, Joanna Maria; Viana, Robson M.; Téllez S, Claudio A.; Pereira, Wagnyr C.; Izolani, Antônio O.; da Silva, Maria Isabel P.

    2006-10-01

    To elucidate tentative assignments of metal-ligand modes of thiosemicarbazide complexes, a structural study and a assignment of the normal vibrations of 2-methylthiosemicarbazide copper(II) nitrate, [Cu(2MeTSC) 2(NO 3) 2] have been done through the ab initio DFT: pBP86/DN** procedure, and through the normal coordinate analysis (NCA). In the vibrational calculations, the elongated Cu sbnd ONO 2 bonds of the nitrate groups were considered in the C dbnd S and C dbnd N tautomers of the complex. DFT calculations had revealed that the infrared spectra can be well interpreted through the C dbnd N tautomer, failing in the prediction of the -NO 2 group wavenumbers. A little difference stabilization energy for the tautomers were found: for the C dbnd N tautomer was E = -3487,36376 a.u., and for the C dbnd S tautomer, E = -3473,93598 a.u. The observed combination bands at 1763.0 and at 1754.0 cm -1 are an indicative that the -NO 3- groups acts as monodentate ligands. Calculations had confirmed the experimental assignment of the infrared spectrum.

  2. Synthesis and characterization of bis-(2-cyano-1-methyl-3-{2- {{(5-methylimidazol-4-yl)methyl}thio}ethyl)guanidine copper(II) sulfate tetrahydrate

    NASA Astrophysics Data System (ADS)

    Rahardjo, Sentot B.; Endah Saraswati, Teguh; Pramono, Edy; Fitriana, Nur

    2016-02-01

    Complex of copper(II) with 2-cyano-1-methyl-3-{2-{{(5-methylimidazol-4- yl)methyl}thio}ethyl)guanidin(xepamet) had been synthesized in 1 : 4 mole ratio of metal to the ligand in methanol. The complex was characterized by metal analysis, thermal gravimetry/differential thermal analyzer (TG/DTA), molar conductivity meter, (Fourier transform infrared spectroscopy) FT-IR, UV-Vis spectroscopy, and magnetic susceptibility balance. The molar conductivity measurement shows that the complex was 2: 1 for electrolyte and SO42- which was acting as a counter ion. The thermal analysis by Thermogravimetric (TG) indicates that the complex contained four molecules of H2O. The Infrared spectral data indicates that functional groups of (C=N) imidazole and (C-S) are coordinated to the center ion Cu2+. Magnetic moment measurement shows that the complex is paramagnetic with peff = 1.78 ± 0.01 BM. Electronic spectra of the complex show a broad band at 608 nm (16447.23 cm-1) are due to Eg→T2g transition. Based on those of characteristics, The complex formula was estimated as [Cu(xepamet)2]SO4.4H2O. The structure of [Cu(xepamet)2]SO4.4H2O complex is probably square planar.

  3. The effect of chain length on the thermal stability of 2-alkylimidazoles on copper and 2-alkylimidazolato copper(II) complexes

    NASA Astrophysics Data System (ADS)

    Yoshida, Shuji; Ishida, Hatsuo

    1985-02-01

    The molecular structure and thermal stability of imidazole, 2-methylimidazole, 2-ethylimidazole, 2-propylimidazole, 2-undecylimidazole, and 2-heptadecylimidazole on copper are studied using FT-IR reflection—absorption spectroscopy. As model compounds of these complexes formed on copper, corresponding imidazole copper(II) complexes are synthesized in solution. The complexes appear to be the semicrystalline or crystalline structure. The series of imidazoles employed on copper indicates the same oxidation and degradation process at high temperatures even though imidazole, 2-methylimidazole and 2-ethylimidazole possess better thermal stability below 150°C. The synthesized complexes indicate poor thermal stability as the chain length of the alkyl substituent increases and the enhanced oxidation by the addition of copper powder. The difference in oxidation between imidazoles on copper and synthesized imidazole complexes are due to the presence of copper ion migrating from the copper substrate to catalyze oxidation and different morphological structure. The difference in oxidation among the imidazole derivatives depend on the melting points and the fraction of the imidazole ring which occupies the molecule.

  4. Binary and ternary new water soluble copper(II) complexes of L-tyrosine and substituted 1,10-phenanthrolines: Effect of substitution on DNA interactions and cytotoxicities

    NASA Astrophysics Data System (ADS)

    İnci, Duygu; Aydın, Rahmiye; Vatan, Özgür; Yılmaz, Dilek; Gençkal, Hasene Mutlu; Zorlu, Yunus; Cavaş, Tolga

    2015-06-01

    Binary and ternary water soluble copper(II) complexes - [Cu(nphen)2(H2O)](NO3)2·H2O (1), [Cu(phen)2(H2O)](NO3)2 (2), [Cu(nphen)(L-tyr)(H2O)]NO3·2H2O (3), [Cu(phen)(tyr)(H2O)] NO3·2H2O (4) - and diquarternary salts of nphen and phen (nphen = 5-nitro-1,10-phenanthroline, phen = 1,10-phenanthroline and tyr = L-tyrosine) have been synthesized and characterized by CHN analysis, 1H NMR, 13C NMR and IR spectroscopy, thermal analysis and single crystal X-ray diffraction techniques. The CT-DNA binding properties of these compounds have been investigated by thermal denaturation measurements, absorption and emission spectroscopy. The supercoiled pUC19 plasmid DNA cleavage activity of these compounds has been explored by agarose gel electrophoresis. The cytotoxicity of these compounds against MCF-7, Caco-2, A549 cancer cells and BEAS-2B healthy cells was also studied by using XTT method. The complexes 1-4 exhibit significant high cytotoxicity with low IC50 values in compared with cisplatin. The effect of the substituents of phen and coordinated amino acid in the above complexes are presented and discussed.

  5. Immobilization of Metal-Organic Framework Copper(II) Benzene-1,3,5-tricarboxylate (CuBTC) onto Cotton Fabric as a Nitric Oxide Release Catalyst.

    PubMed

    Neufeld, Megan J; Harding, Jacqueline L; Reynolds, Melissa M

    2015-12-01

    Immobilization of metal-organic frameworks (MOFs) onto flexible polymeric substrates as secondary supports expands the versatility of MOFs for surface coatings for the development of functional materials. In this work, we demonstrate the deposition of copper(II) benzene-1,3,5-tricarboxylate (CuBTC) crystals directly onto the surface of carboxyl-functionalized cotton capable of generating the therapeutic bioagent nitric oxide (NO) from endogenous sources. Characterization of the CuBTC-cotton material by XRD, ATR-IR, and UV-vis indicate that CuBTC is successfully immobilized on the cotton fabric. In addition, SEM imaging reveals excellent surface coverage with well-defined CuBTC crystals. Subsequently, the CuBTC-cotton material was evaluated as a supported heterogeneous catalyst for the generation of NO using S-nitrosocysteamine as the substrate. The resulting reactivity is consistent with the activity observed for unsupported CuBTC particles. Overall, this work demonstrates deposition of MOFs onto a flexible polymeric material with excellent coverage as well as catalytic NO release from S-nitrosocysteamine at therapeutic levels. PMID:26595600

  6. Kinetic and Spectroscopic Studies of Aerobic Copper(II)-Catalyzed Methoxylation of Arylboronic Esters and Insights into Aryl Transmetalation to Copper(II).

    PubMed

    King, Amanda E; Ryland, Bradford L; Brunold, Thomas C; Stahl, Shannon S

    2012-11-26

    We previously reported a preliminary mechanistic study of aerobic Cu(OAc)(2)-catalyzed methoxylation of 4-tolylboronic ester (King, et al. J. Am. Chem. Soc., 2009, 131, 5044-5045), which revealed that aryl transmetalation from the boronic ester to Cu(II) is the turnover-limiting step. In the present study, more-thorough kinetic and spectroscopic studies provide additional insights into transmetalation pathway and the identity of the Cu(II) catalyst resting state(s). EPR spectroscopic studies show that at least two copper(II) species are present under catalytic conditions and their relative populations vary as a function of reaction time and acidity of the arylboronic ester, and are influenced by addition of acetic acid or acetate to the reaction mixture. Analysis of kinetic data and (11)B NMR and EPR spectra under diverse reaction conditions suggests that aryl transmetalation occurs from a tetracoordinate, anionic boronate to a cationic Cu(II) species, mediated by a methoxide-bridge. PMID:23204631

  7. Copper(II) complexes with naringenin and hesperetin: cytotoxic activity against A 549 human lung adenocarcinoma cells and investigation on the mode of action.

    PubMed

    Tamayo, Lenka V; Gouvea, Ligiane R; Sousa, Anna C; Albuquerque, Ronniel M; Teixeira, Sarah Fernandes; de Azevedo, Ricardo Alexandre; Louro, Sonia R W; Ferreira, Adilson Kleber; Beraldo, Heloisa

    2016-02-01

    Copper(II) complexes [Cu(H2O)2 (L1)(phen)](ClO4) (1) and [Cu(H2O)(L2)(phen)](ClO4) (2) (HL1 = naringenin; HL2 = hesperetin) were obtained, in which an anionic flavonoid ligand is attached to the metal center along with 1,10-phenanthroline (phen) as co-ligand. Complexes (1) and (2) were assayed for their cytotoxic activity against A549 lung carcinoma and against normal lung fibroblasts (LL-24) and human umbilical vein endothelial cells (HUVEC). We found IC50 = 16.42 µM (1) and IC50 = 5.82 µM (2) against A549 tumor cells. Complexes (1) and (2) exhibited slight specificity, being more cytotoxic against malignant than against non-malignant cells. 1 and 2 induced apoptosis on A549 cells in a mitochondria-independent pathway, and showed antioxidant activity. The antioxidant effect of the complexes could possibly improve their apoptotic action, most likely by a PI3K-independent reduction of autophagy. Complexes (1) and (2) interact in vitro with calf thymus DNA by an intercalative binding mode. EPR data indicated that 1 and 2 interact with human serum albumin (HSA) forming mixed ligand species. PMID:26582127

  8. Binary and ternary new water soluble copper(II) complexes of l-tyrosine and substituted 1,10-phenanthrolines: effect of substitution on DNA interactions and cytotoxicities.

    PubMed

    İnci, Duygu; Aydın, Rahmiye; Vatan, Özgür; Yılmaz, Dilek; Gençkal, Hasene Mutlu; Zorlu, Yunus; Cavaş, Tolga

    2015-06-15

    Binary and ternary water soluble copper(II) complexes - [Cu(nphen)2(H2O)](NO3)2·H2O (1), [Cu(phen)2(H2O)](NO3)2 (2), [Cu(nphen)(l-tyr)(H2O)]NO3·2H2O (3), [Cu(phen)(tyr)(H2O)] NO3·2H2O (4) - and diquarternary salts of nphen and phen (nphen=5-nitro-1,10-phenanthroline, phen=1,10-phenanthroline and tyr=l-tyrosine) have been synthesized and characterized by CHN analysis, (1)H NMR, (13)C NMR and IR spectroscopy, thermal analysis and single crystal X-ray diffraction techniques. The CT-DNA binding properties of these compounds have been investigated by thermal denaturation measurements, absorption and emission spectroscopy. The supercoiled pUC19 plasmid DNA cleavage activity of these compounds has been explored by agarose gel electrophoresis. The cytotoxicity of these compounds against MCF-7, Caco-2, A549 cancer cells and BEAS-2B healthy cells was also studied by using XTT method. The complexes 1-4 exhibit significant high cytotoxicity with low IC50 values in compared with cisplatin. The effect of the substituents of phen and coordinated amino acid in the above complexes are presented and discussed. PMID:25795604

  9. Copper(II) coordination chain complexes with the 3,5-diacetyl-4-methylpyrazole dioxime ligand: Synthesis, crystal structures and magnetic properties

    NASA Astrophysics Data System (ADS)

    Outirite, Moha; Mernari, Bouchaib; Bentiss, Fouad; Capet, Frederic; Lagrenée, Michel

    2011-03-01

    3,5-Diacetyl-4-methylpyrazole dioxime (dampdoH 3) has been found to form with copper(II), in the presence of different anions (perchlorate, nitrate, triflate and tetrafluoroborate), four new dimeric complexes, [Cu 2(dampdoH 2) 2(ClO 4) 2] ( 1); [Cu 2(dampdoH 2) 2(H 2O) 2]2NO 3 ( 2); [Cu 2(dampdoH 2) 2(CF 3SO 3) 2] ( 3) and [Cu 2(dampdoH 2) 2(BF 4) 2] ( 4). The molecular structure of [Cu 2(dampdoH 3) 2] 2+ which is the common unit for the four complexes is composed of binuclear species where one of the oxime functions has the classical structure while the second function has a zwitterionic structure. For the four complexes these binuclear units are parallel and are bound together by a strong intermolecular bond to create an infinite 1D chain expanding along the crystallographic " a" axis. Variable-temperature magnetic susceptibility measurements for complex 1 indicate a very strong antiferromagnetic exchange coupling intra or/and interdimeric ring, the J1 value of the intradimer coupling being strongest than the interbinuclear coupling J2 ( J1 = -346 cm -1, J2 = -119.15 cm -1).

  10. Enhanced photocatalytic degradation activity over TiO2 nanotubes co-sensitized by reduced graphene oxide and copper(II) meso-tetra(4-carboxyphenyl)porphyrin

    NASA Astrophysics Data System (ADS)

    Wei, Meng; Wan, Junmin; Hu, Zhiwen; Peng, Zhiqin; Wang, Bing

    2016-07-01

    In this paper, TiO2 nanotubes (TNT) co-sensitized with copper(II) meso-tetra(4-carboxyphenyl)porphyrin (CuTCPP) and reduced graphene oxide nanosheets (rGO), which was fabricated through two-step improved hydrothermal method and heating reflux process. The effect of rGO and CuTCPP on the co-photocatalytic behavior of TNT for the degradation of Methylene Blue (MB) were measured under visible light irradiation. The photocatalysts have been characterized and analyzed by high-resolution transmission electron microscopy (TEM), selected area electronic diffraction (SAED), elemental mapping by energy-dispersive X-ray spectroscopy (EDX), powder X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, Raman spectroscopy, ultraviolet-visible diffuse reflectance spectroscopy (DRS), photoluminescence spectroscopy (PL), X-ray photoelectron spectroscopy (XPS), Brunauer-Emmett-Teller (BET) and electron paramagnetic resonance (EPR). The results provide a deeper insight into the co-photocatalytic mechanism of CuTCPP/rGO-TNT nanocomposites. The degradation results showed a purification of more than 95% MB in wastewater, which is about 5 times higher than that of the pure TNT. The results also confirm the prepared CuTCPP/rGO-TNT nanocomposites possess superior co-photocatalytic activities.

  11. Characterization of copper(II) complexes of N4, N4-disubstituted thiosemicarbazones of 2-acetylpyridine by combined evaluation of electronic and ESR parameters

    NASA Astrophysics Data System (ADS)

    Jain, Satendra K.; Garg, Bhagwan S.; Bhoon, Yudhvir K.

    Copper(II) complexes of 2-acetylpyridine 4,4-dimethyl-3-thiosemicarbazone (L'H) and 2-acetylpyridine 4-(4-methylpiperidinyl)-3-thiosemicarbazone (LH) of the general formula CuLX (where L is a deprotonated ligand and X = F -, Cl -, Br -, I -, OAc - and NO -3) have been synthesized and characterized by elemental analysis, magnetic susceptibility measurements between 93 and 298 K in the polycrystalline state, i.r. spectra, electronic spectra, conductivity measurements and ESR spectra recorded in the polycrystalline state, in chloroform and dimethylformamide solution at room temperature and at 77K. The molar conductivities measured in dimethylformamide for all complexes show them to be non-electrolytes. The terdentate character of the ligands in all the complexes is inferred from i.r. spectral studies. The i.r. spectra also confirm the monodentate nature of the polyatomic anions such as nitrate and acetate. The electronic spectra in Nujol mulls, chloroform or dimethylformamide solution suggest planar geometry for all of the complexes. The calculated ESR parameters show an axial dx2- y2 ground state and suggest coordination through sulphur in agreement with the i.r. results. Little change in the value of g with temperature indicates no significant change in planarity of these four coordinated species. ESR spectra in solution at room temperature and 77 K also suggest a strong covalent environment with strong in-plane sigma and pi bonds provided by the ligands.

  12. Two polymorphs of 4-(4-hexyloxyphenyl)-2,6-di(pyrazin-2-yl)pyridine and the crystal structure of its copper(II) complex

    NASA Astrophysics Data System (ADS)

    Li, Li; Zhang, Yuan Zhuo; Yang, Chengxiong; Liu, E.; Fettinger, James C.; Zhang, Guoqi

    2016-04-01

    4-(4-Hexyloxyphenyl)-2,6-di(pyrazin-2-yl)pyridine (1), an analogue of the archetypal ligand, 2,2‧:6‧,2″-terpyridine containing additional outer N-donating sets is synthesized through the facile one-step Kröhnke condensation reaction. It is observed that different crystallization conditions affect the molecular packing in 1 and as a result two crystal polymorphs are resolved via single-crystal X-ray diffraction analysis. Distinct intermolecular π…π interactions were found to play a crucial role in driving the formation of polymorphism. The complexation of this ligand with copper(II) dichloride resulted in the formation of a mononuclear complex with CuII being in the chelating cavity of 1. X-ray structural analysis confirms that this is the only product even though the synthesis was conducted under various conditions, remarkably different from the known structure with three CuII cores.

  13. Synthesis, characterization, cellular uptake and interaction with native DNA of a bis(pyridyl)-1,2,4-oxadiazole copper(II) complex.

    PubMed

    Terenzi, Alessio; Barone, Giampaolo; Piccionello, Antonio Palumbo; Giorgi, Gianluca; Guarcello, Annalisa; Portanova, Patrizia; Calvaruso, Giuseppe; Buscemi, Silvestre; Vivona, Nicolò; Pace, Andrea

    2010-10-14

    The copper(II) complex of 3,5-bis(2'-pyridyl)-1,2,4-oxadiazole was synthesized and characterized. X-Ray crystallography revealed that the complex consists of a discrete [Cu(3,5-bis(2'-pyridyl)-1,2,4-oxadiazole)(2)(H(2)O)(2)](2+) cation and two ClO(4)(-) anions. The Cu(II) coordination sphere has a distorted octahedral geometry and each ligand chelates the copper ion through the N(4) nitrogen of the oxadiazole ring and the nitrogen of one pyridine moiety. The coordinated water molecules are in cis position and each of them is H-bonded to the 5-pyridyl nitrogen of the oxadiazole ligand and to an oxygen of the perchlorate anion. Biological assays showed that, despite the free ligand not being effective, [Cu(3,5-bis(2'-pyridyl)-1,2,4-oxadiazole)(2)(H(2)O)(2)](2+) reduced the vitality of human hepatoblastoma HepG2 and colorectal carcinoma HT29 cells in a dose- and time-dependent manner. The interaction of the cationic copper complex with native DNA was investigated by variable-temperature UV-vis spectroscopy, circular dichroism, viscosity and gel electrophoresis, indicating that it is a groove binder with binding constant K(b) = 2.2 × 10(4) M(-1). PMID:20820603

  14. Chiral tetranuclear and dinuclear copper(ii) complexes for TEMPO-mediated aerobic oxidation of alcohols: are four metal centres better than two?

    PubMed

    Zhang, Guoqi; Proni, Gloria; Zhao, Sherry; Constable, Edwin C; Housecroft, Catherine E; Neuburger, Markus; Zampese, Jennifer A

    2014-08-28

    The one-pot reaction of 3,5-di-tert-butyl-2-hydroxybenzaldehyde, (R)-2-aminoglycinol and Cu(OAc)2·2H2O in a 1 : 1 : 1 ratio in the presence of triethylamine led to the isolation of X-ray quality crystals of the chiral complex (R)- in high yield. The single crystal structure of (R)- reveals a tetranuclear copper(ii) complex that contains a {Cu4(μ-O)2(μ3-O)2N4O4} core. A reaction using (1S,2R)-2-amino-1,2-diphenylethanol as precursor under the same conditions generated the chiral complex (S,R)-; its structure was determined by single crystal X-ray crystallography and was found to contain a {Cu2(μ-O)2N2O2} core. Both (R)- and (S,R)- have been used for catalytic aerobic oxidation of benzylic alcohols in combination with the TEMPO (2,2,6,6-tetramethylpiperidinyl-1-oxyl) radical. (R)- selectively catalyses the conversion of various aromatic primary alcohols to the corresponding aldehydes with high yields (99%) and TONs (770) in the air, while (S,R)- exhibits less promising catalytic performance under the same reaction conditions. The role of the cluster structures in (R)- and (S,R)- in controlling the reactivity towards aerobic oxidation reactions is discussed. PMID:24986135

  15. Syntheses, crystal structures, magnetic properties, and EPR spectra of tetranuclear copper(II) complexes featuring pairs of "roof-shaped" Cu2X2 dimers with hydroxide, methoxide, and azide bridges.

    PubMed

    Graham, B; Hearn, M T; Junk, P C; Kepert, C M; Mabbs, F E; Moubaraki, B; Murray, K S; Spiccia, L

    2001-03-26

    Hydroxo- and methoxo-bridged tetranuclear copper(II) complexes of the tetramacrocyclic ligand 1,2,4,5-tetrakis(1,4,7-triazacyclonon-1-ylmethyl)benzene (Ldur), have been prepared from [Cu4Ldur(H2O)8](ClO4)8.9H2O (1). Addition of base to an aqueous solution of 1 gave [Cu4Ldur(mu2-OH)4](ClO4)4 (2). Diffusion of MeOH into a DMF solution of 2 produces [Cu4Ldur(mu2-OMe)4](ClO4)4.HClO4.2/3MeOH (3), a complex which hydrolyzes on exposure to moisture regenerating 2. The structurally related azido-bridged complex, [Cu4Ldur(mu2-N3)4](PF6)4.4H2O.6CH3CN (4), was produced by reaction of Ldur with 4 molar equiv of Cu(OAc)2.H2O and NaN3 in the presence of excess KPF6. Compounds 2-4 crystallize in the triclinic space group P1 (No. 2) with a = 10.248(1) A, b = 12.130(2) A, c = 14.353(2) A, alpha = 82.23(1) degrees, beta = 80.79(1) degrees, gamma = 65.71(1) degrees, and Z = 1 for 2, a = 10.2985(4) A, b = 12.1182(4) A, c = 13.9705(3) A, alpha = 89.978(2) degrees, beta = 82.038(2) degrees, gamma = 65.095(2) degrees, and Z = 1 for 3, and a = 12.059(2) A, b = 12.554(2) A, c = 14.051(2) A, alpha = 91.85(1) degrees, beta = 98.22(1) degrees, gamma = 105.62(1) degrees, and Z = 1 for 4. The complexes feature pairs of isolated dibridged copper(II) dimers with "roof-shaped" Cu2(mu2-X)2 cores (X = OH-, OMe-, N3-), as indicated by the dihedral angle between the two CuX2 planes (159 degrees for 2, 161 degrees for 3, and 153 degrees for 4). This leads to Cu.Cu distances of 2.940(4) A for 2, 2.962(1) A for 3, and 3.006(5) A for 4. Variable-temperature magnetic susceptibility measurements indicate weak antiferromagnetic coupling (J = -27 cm(-1)) for the hydroxo-bridged copper(II) centers in 2 and very strong antiferromagnetic coupling (J = -269 cm(-1)) for the methoxo-bridged copper(II) centers in 3. Pairs of copper(II) centers in 4 display the strongest ferromagnetic interaction (J = 94 cm(-1)) reported thus far for bis(mu2-1,1-azido)-bridged dicopper units. Spectral measurements on a neat powdered

  16. DFT, characterization and investigation of vibrational spectroscopy of 4-(4-hydroxy)-3-(2-pyrazine-2-carbonyl)hydrazonomethylphenyl-diazen-yl-benzenesulfonamide and its copper(II) complex

    NASA Astrophysics Data System (ADS)

    Ammar, Reda A. A.; Alaghaz, Abdel-Nasser M. A.; Elhenawy, Ahmed A.

    2014-06-01

    Azo-Schiff-base complex of Cu(II) has been synthesized and characterized by elemental, spectral and thermal studies. The conductance data indicate the non-electrolytic nature of the complex. The IR spectra of the prepared complex was suggested that the azo-Schiff-base ligand [4-(4-hydroxy)-3-(2-pyrazine-2-carbonyl)hydrazonomethylphenyl-diazen-yl-benzenesulfonamide] (H2L) behaves as a tri-dentate ligand through the carbonyl oxygen atom, azomethine nitrogen atom and phenolic oxygen atom (ONO). The surface morphology (SEM) of the ligand and its copper(II) complex was studied using SEM analysis. X-ray powder diffraction (XRD) helps to determine the cell parameters of the complex. Transmission electron microscopy (TEM) indicated spherical particles of ∼200 nm diameter. The physico-chemical studies revealed octahedral geometry around copper ion. The EPR spectra of copper complex in DMSO at 300 and 77 K were recorded and their salient feature was reported. The redox behavior of the ligand and its copper(II) complex were studied using cyclic voltammetry. Thermal properties and decomposition kinetics of copper(II) complex was investigated. The interpretation mathematical analysis and evaluation of kinetic parameters (E, A, ΔH, ΔS and ΔG) of all thermal decomposition stages have been evaluated using Coats-Redfern (CR), Horowitz-Metzger (HM) and Piloyan-Novikova (PN) equations. Moreover, the density functional theory studies are discussed for ligand, using DFT/B3LYP with 6-31G* and 6-311G* level of theory, the absorption spectra has been computed by using time dependent at TD-DFT/B3LYP with 6-31G* and 6-311G* level of theory. The HOMO-LUMO energy gap of studied systems has been discussed.

  17. Reversible DNA i-motif to hairpin switching induced by copper(ii) cations† †Electronic supplementary information (ESI) available: Experimental, preliminary experiments, data fitting and supporting data. See DOI: 10.1039/c5cc05111h Click here for additional data file.

    PubMed Central

    Day, Henry Albert; Wright, Elisé Patricia; MacDonald, Colin John; Gates, Andrew James

    2015-01-01

    i-Motif DNA structures have previously been utilised for many different nanotechnological applications, but all have used changes in pH to fold the DNA. Herein we describe how copper(ii) cations can alter the conformation of i-motif DNA into an alternative hairpin structure which is reversible by chelation with EDTA. PMID:26252811

  18. Label-free colorimetric biosensing of copper(II) ions with unimolecular self-cleaving deoxyribozymes and unmodified gold nanoparticle probes

    NASA Astrophysics Data System (ADS)

    Wang, Yong; Yang, Fan; Yang, Xiurong

    2010-05-01

    Using unimolecular copper(II)-dependent self-cleaving deoxyribozymes (DNAzymes), a label-free colorimetric biosensor for copper(II) ions (Cu2 + ) has been developed based on the sequence-length-dependent adsorption of single-stranded deoxyribonucleic acid (ssDNA) on unmodified gold nanoparticles (AuNPs). In the presence of Cu2 + , the Cu2 + -dependent DNAzyme could be self-cleaved into short ssDNA fragments. The cleaved short ssDNA could adsorb rapidly onto the surface of the AuNPs. This enhanced the stability of the AuNPs against salt-induced aggregation, and thus the solution color remained red. In the absence of Cu2 + , however, uncleaved long ssDNA adsorbed relatively slowly onto the AuNPs and upon the addition of salt, the electrostatic repulsion between the AuNPs was screened, resulting in aggregation of the AuNPs which produced a red-to-blue color change. Thus, Cu2 + detection could be realized by monitoring the color change of the AuNPs. The calibration curve showed that the absorption ratio values at 520 and 620 nm increased linearly over the Cu2 + concentration range of 0.625-15 µM, with a limit of detection of 290 nM. The other environmentally relevant metal ions did not interfere with the determination of Cu2 + . Subsequently, the assay was employed to determine Cu2 + in several water samples, and the results were satisfactory. It is expected that the present colorimetric strategy will be possibly extended to the detection of cofactors of other in vitro-selected unimolecular self-cleaving DNAzymes, such as amino acids, nucleic acids, metal ions and small organic molecules.

  19. Mixed ligand copper(II) complexes of 2,9-dimethyl-1,10-phenanthroline: tridentate 3N primary ligands determine DNA binding and cleavage and cytotoxicity.

    PubMed

    Ganeshpandian, Mani; Ramakrishnan, Sethu; Palaniandavar, Mallayan; Suresh, Eringathodi; Riyasdeen, Anvarbatcha; Akbarsha, Mohammad Abdulkadher

    2014-11-01

    A series of mononuclear mixed ligand copper(II) complexes of the type [Cu(L)(2,9-dmp)](ClO4)21-4, where L is a tridentate 3N ligand such as diethylenetriamine (L1) (1) or N-methyl-N'-(pyrid-2-yl-methyl)ethylenediamine (L2) (2) or di(2-picolyl)amine (L3) (3) or bis(pyrid-2-ylmethyl)-N-methylamine (L4) (4) and 2,9-dmp is 2,9-dimethyl-1,10-phenanthroline, has been isolated and characterized. The complexes 1 and 3 possess square-based pyramidal coordination geometry. Absorption spectral studies reveal that the intrinsic DNA binding affinity varies as 1>2>3>4. The higher DNA binding affinity of 1 arises from L1, which offers lower steric hindrance toward intercalation of 2,9-dmp co-ligand into DNA base pairs and is involved in hydrogen bonding interaction with DNA. Interestingly, all the complexes cleave pUC19 supercoiled DNA in the absence of an activating agent. They also exhibit oxidative (H2O2) DNA cleavage ability, which varies as 1>2>3>4, the highest cleavage efficiency of 1 being due to the largest amount of ROS it generates. The tryptophan emission-quenching experiment reveals that the stronger binding of 3 and 4 with bovine serum albumin (BSA) in the hydrophobic region, which is in line with DNA viscosity measurements. The IC50 values of 1-4 for MCF-7 breast cancer cell line are lower than that of cisplatin. Flow cytometry analysis reveals that 1 mediates the arrest of S and G2/M phases in the cell cycle progression at 24h harvesting time, which progresses into apoptosis. Hoechst 33258 staining studies indicate the higher potency of 1 to induce apoptosis. PMID:25151036

  20. Copper(II) complexes with 4-(1H-1, 2, 4-trizol-1-ylmethyl) benzoic acid: Syntheses, crystal structures and antifungal activities

    SciTech Connect

    Xiong, Pingping; Li, Jie; Bu, Huaiyu; Wei, Qing; Zhang, Ruolin; Chen, Sanping

    2014-07-01

    Reaction of Cu(II) with an asymmetric semi-rigid organic ligand 4-(1H-1, 2, 4-trizol-1-ylmethyl) benzoic acid (HL), yielded five compounds, [Cu{sub 0.5}L]{sub n} (1), [Cu(HL){sub 2}Cl{sub 2}]{sub n} (2), [Cu(HL){sub 2}Cl{sub 2}(H{sub 2}O)] (3), [Cu(L){sub 2}(H{sub 2}O)]{sub n} (4) and [Cu(L)(phen)(HCO{sub 2})]{sub n} (5), which have been fully characterized by infrared spectroscopy, elemental analysis, and single-crystal X-ray diffraction. As for compounds 1, 2 and 5, Cu(II) is bridged through HL, Cl{sup -}, and formic acid, respectively, featuring 1D chain-structure. In compound 3, Cu(II) with hexahedral coordination sphere is assembled through hydrogen-bonding into 3D supramolecular framework. In compound 4, 1D chain units –Cu–O–Cu–O– are ligand-bridged into a 3D network. All compounds were tested on fungi (Fusarium graminearum, Altemaria solani, Macrophoma kawatsukai, Alternaria alternata and Colletotrichum gloeosporioides). Compound 1 exhibits a better antifungal effect compared to other compounds. An effect of structure on the antifungal activity has also been correlated. - Graphical abstract: Copper(II) compounds with 4-(1H-1, 2, 4-trizol-1-ylmethyl) benzoic acid, were prepared, structurally characterized and investigated for antifungal activity. - Highlights: • The title compounds formed by thermodynamics and thermokinetics. • The five compounds show higher inhibition percentage than reactants. • The structure effect on the antifungal activity.