Sample records for copperii schiff-base complexes

  1. Coordination chemistry, thermodynamics and DFT calculations of copper(II) NNOS Schiff base complexes.

    PubMed

    Esmaielzadeh, Sheida; Azimian, Leila; Shekoohi, Khadijeh; Mohammadi, Khosro

    2014-12-10

    Synthesis, magnetic and spectroscopy techniques are described for five copper(II) containing tetradentate Schiff bases are synthesized from methyl-2-(N-2'-aminoethane), (1-methyl-2'-aminoethane), (3-aminopropylamino)cyclopentenedithiocarboxylate. Molar conductance and infrared spectral evidences indicate that the complexes are four-coordinate in which the Schiff bases are coordinated as NNOS ligands. Room temperature ?eff values for the complexes are 1.71-1.80B.M. corresponding to one unpaired electron respectively. The formation constants and free energies were measured spectrophotometrically, at constant ionic strength 0.1M (NaClO4), at 25?C in DMF solvent. Also, the DFT calculations were carried out to determine the structural and the geometrical properties of the complexes. The DFT results are further supported by the experimental formation constants of these complexes. PMID:24992917

  2. Biological activity and coordination modes of copper(II) complexes of Schiff base-derived coumarin ligands.

    PubMed

    Creaven, Bernadette Sarah; Czeglédi, Eszter; Devereux, Michael; Enyedy, Éva Anna; Foltyn-Arfa Kia, Agnieszka; Karcz, Dariusz; Kellett, Andrew; McClean, Siobhán; Nagy, Nóra Veronika; Noble, Andy; Rockenbauer, Antal; Szabó-Plánka, Terézia; Walsh, Maureen

    2010-12-01

    The coordination modes of copper(II) complexes of Schiff base-derived coumarin ligands, which had previously shown good anti-Candida activity, were investigated by pH-potentiometric and UV-Vis spectroscopic methods. These studies confirmed the coordination mode of the ligands to be through the N of the imine and deprotonated phenol of the coumarin-derived ligand in solution. In addition, the more active complexes and their corresponding ligands were investigated in the presence of copper(II) in liquid and frozen solution by ESR spectroscopic methods. A series of secondary amine derivatives of the Schiff base ligands, were isolated with good solubility characteristics but showed little anti-Candida activity. However, cytotoxicity studies of the secondary amines, together with the copper complexes and their corresponding ligands, against human colon cancer and human breast cancer cells identified the chemotherapeutic potential of these new ligands. PMID:20949224

  3. 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-?-naphthylamide (PA?N). 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 ?M. This pioneer study clearly indicates that the conjugation of cell-penetrating peptides (CPPs) to dithiocarbazate compounds greatly enhances their therapeutic potential. PMID:25382115

  4. Structure and magnetic properties of a copper(II) complex with the schiff base derived from 2,2,6,6-tetramethyl-4-aminopiperidine-1-iminoxyl

    Microsoft Academic Search

    L. O. Atovmyan; N. I. Golovina; G. A. Klitskaya; A. A. Medzhidov; A. V. Zvarykina; V. B. Stryukov; D. N. Fedutin

    1975-01-01

    The crystal structure of a copper(II) complex with a Schiff base containing iminoxyI radicals has been determined. Measurements of magnetic susceptibility in the 1.3-300~ range have shown that the magnetic system of the complex consists of triads of interacting spins. The ESR spectra of single crystals of the complex measured at 1.3-300~ have led to a conclusion about interaction between

  5. Novel homo- and hetero-nuclear copper(II) complexes of tetradentate Schiff bases: synthesis, characterization, solvent-extraction and catalase-like activity studies.

    PubMed

    Dede, Bülent; Karipcin, Fatma; Cengiz, Mustafa

    2009-04-30

    Twelve homo- and hetero-nuclear copper(II) complexes of tetradentate Schiff base ligands containing N(4) donor sets have been prepared by employing several steps. The characterization and nature of bonding of the complexes have been deduced from elemental analysis, FT-IR, molar conductivity, magnetic moment measurements and thermal analysis. The three Schiff base ligands were further identified using (1)H and (13)C NMR spectra. All copper(II) complexes are 1:2 electrolytes as shown by their molar conductivities (Lambda(M)) in DMF and paramagnetic. The subnormal magnetic moment values of the di- and tri-nuclear complexes explained by a very strong anti-ferromagnetic interaction. The extraction ability of the ligands has been examined by the liquid-liquid extraction of selected transition metal (Mn(2+), Co(2+), Ni(2+), Cu(2+), Zn(2+), Pb(2+), Cd(2+), Hg(2+)) cations. The ligands show strong binding ability toward copper(II) ion. Furthermore the homo- and hetero-nuclear copper(II) complexes were each tested for their ability to catalyse the disproportionation of hydrogen peroxide in the presence of the added base imidazole. PMID:18762369

  6. 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.

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

    NASA Astrophysics Data System (ADS)

    ?enol, 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.

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

    PubMed

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

    2014-03-25

    The mononuclear copper(II) complexes (1&2) of ligands L(1) [N,N'-bis(2-hydroxy-5-methylbenzyl)-1,4-bis(3-iminopropyl)piperazine] or L(2) [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 L(1) and L(2) 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. PMID:24317263

  9. 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.

  10. Synthesis, characterization, and antimicrobial activities of nickel(II) and copper(II) Schiff-base complexes

    Microsoft Academic Search

    M. Rajasekar; S. Sreedaran; R. Prabu; V. Narayanan; R. Jegadeesh; N. Raaman; A. Kalilur Rahiman

    2010-01-01

    Ni(II) and Cu(II) metal complexes of simple unsymmetrical Schiff-base ligands derived from salicylaldehyde\\/5-methylsalicylaldehyde and ethylenediamine or diaminomaleonitrile (DMN) were synthesized. The ligands and their complexes were characterized by elemental analysis, H NMR, FT IR, and mass spectroscopy. The electronic spectra of the complexes show d–d transitions in the region at 450–600 nm. Electrochemical studies of the complexes reveal that all

  11. DNA Cleavage, Cytotoxic Activities, and Antimicrobial Studies of Ternary Copper(II) Complexes of Isoxazole Schiff Base and Heterocyclic Compounds

    PubMed Central

    Chityala, Vijay Kumar; Sathish Kumar, K.; Macha, Ramesh; Tigulla, Parthasarathy; Shivaraj

    2014-01-01

    Novel mixed ligand bivalent copper complexes [Cu. L. A. ClO4] and [Cu. L. A] where “L” is Schiff bases, namely 2-((3,4-dimethylisoxazol-5-ylimino)methyl)-4-bromophenol (DMIIMBP)/2-((3,4-dimethylisoxazol-5-ylimino)methyl)-4-chlorophenol (DMIIMCP), and “A” is heterocyclic compound, such as 1,10-phenanthroline (phen)/2,21-bipyridyl (bipy)/8-hydroxyquinoline (oxine)/5-chloro-8-hydroxyquinoline (5-Cl-oxine), have been synthesized. These complexes have been characterized by IR, UV-Vis, ESR, elemental analysis, magnetic moments, TG, and DTA. On the basis of spectral studies and analytical data, five-coordinated square pyramidal/four-coordinated square planar geometry is assigned to all complexes. The ligands and their ternary complexes with Cu(II) have been screened for antimicrobial activity against bacteria and fungi by paper disc method. The antimicrobial studies of Schiff bases and their metal complexes showed significant activity and further it is observed that the metal complexes showed more activity than corresponding Schiff bases. In vitro antitumor activity of Cu(II) complexes was assayed against human cervical carcinoma (HeLa) cancer cells and it was observed that few complexes exhibit good antitumor activity on HeLa cell lines. The DNA cleavage studies have also been carried out on pBR 322 and it is observed that these Cu(II) complexes are capable of cleaving supercoiled plasmid DNA in the presence of H2O2 and UV light. PMID:24895493

  12. 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.

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

    PubMed

    Barwiolek, Magdalena; Szlyk, Edward; Muzio?, 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 ?* ? 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 aromatic rings were discussed, suggesting the tetrahedral distortion of the central ion of the coordination sphere in solution. PMID:21922095

  14. Synthesis, characterization, crystal structure and antimicrobial activity of copper(II) complexes with the Schiff base derived from 2-hydroxy-4-methoxybenzaldehyde.

    PubMed

    Pahon?u, Elena; Ilie?, Diana-Carolina; Shova, Sergiu; Paraschivescu, Codru?a; Badea, Mihaela; Gulea, Aurelian; Ro?u, Tudor

    2015-01-01

    A novel Schiff base, ethyl 4-[(E)-(2-hydroxy-4-methoxyphenyl)methylene-amino]benzoate (HL), was prepared and structurally characterized on the basis of elemental analyses, (1)H NMR, (13)C NMR, UV-Vis and IR spectral data. Six new copper(II) complexes, [Cu(L)(NO3)(H2O)2] (1), [Cu(L)2] (2), [Cu(L)(OAc)] (3), [Cu2 (L)2Cl2(H2O)4] (4), [Cu(L)(ClO4)(H2O)] (5) and [Cu2(L2S)(ClO4)(H2O)]ClO4·H2O (6) have been synthesized. The characterization of the newly formed compounds was done by IR, UV-Vis, EPR, FAB mass spectroscopy, elemental and thermal analysis, magnetic susceptibility measurements and molar electric conductivity. The crystal structures of Schiff base and the complex [Cu2(L2S)(ClO4)(H2O)]ClO4·H2O (6) have been determined by single crystal X-ray diffraction studies. Both copper atoms display a distorted octahedral coordination type [O4NS]. This coordination is ensured by three phenol oxygen, two of which being related to the µ-oxo-bridge, the nitrogen atoms of the azomethine group and the sulfur atoms that come from the polydentate ligand. The in vitro antimicrobial activity against Escherichia coli ATCC 25922, Salmonella enteritidis, Staphylococcus aureus ATCC 25923, Enterococcus and Candida albicans strains was studied and compared with that of free ligand. The complexes 1, 2, 5 showed a better antimicrobial activity than the Schiff base against the tested microorganisms. PMID:25849802

  15. 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 ?g mL -1 for calf thymus DNA (CT-DNA), 0.10-36 ?g mL -1 for yeast DNA and 0.01-10.01 ?g 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.

  16. 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

  17. Synthesis, characterization and DNA interaction of new copper(II) complexes of Schiff base-aroylhydrazones bearing naphthalene ring.

    PubMed

    Gökçe, Cansu; Gup, Ramazan

    2013-05-01

    Two new copper(II) complexes with the condensation products of methyl 2-naphthyl ketone with 4-hydroxybenzohydrazide, 4-hydroxy-N'-[(1Z)-1-(naphthalen-2-yl)ethylidene]benzohydrazide [HL(1)] and (Z)-ethyl 2-(4-(2-(1-(naphthalen-2-yl)ethylidene)hydrazinecarbonyl)phenoxy)acetate (HL(2)) were synthesized and characterized by elemental analysis, infrared spectra, UV-Vis electronic absorption spectra, magnetic susceptibility measurements, TGA, powder XRD and SEM-EDS. The binding properties of the copper(II) complexes with calf thymus DNA were studied by using the absorption titration method. DNA cleavage activities of the synthesized copper complexes were examined by using agarose gel electrophoresis. The effect of complex concentration on the DNA cleavage reactions in the absence and presence of H2O2 was also investigated. The experimental results suggest that the copper complexes bind significantly to calf thymus DNA by both groove binding and intercalation modes and cleavage effectively pBR322 DNA. The mechanistic studies demonstrate that a hydrogen peroxide-derived species and singlet oxygen ((1)O2) are the active oxidative species for DNA cleavage. PMID:23562627

  18. Structure-Activity Relationships for Some Diamine, Triamine and Schiff Base Derivatives and Their Copper(II) Complexes

    PubMed Central

    Bolos, C. A.; Nikolov, G. St.; Ekateriniadou, L.; Kortsaris, A.; Kyriakidis, D. A.

    1998-01-01

    Ethylenediamine (en), putrescine (pu), diethylenetriamine (dien), dipropylenetriamine (dpta), spermidine (spmd) and their CuII compounds as well as the Schiff bases with 2-furaldehyde (dienOO), 2- thiophenecarboxaldehyde (dienSS) and pyrrole-2-carboxaldehyde (dienNN) of dien and that of dpta with 2- thiophenecarboxaldehyde (dptaSS), were prepared and characterised. They were tested against Bacillus substilis, Bacillus cereus, Staphylococcus aureus, Escherichia coli, Proteus vulgaris and Xanthomonas campestris as antibacterial reagents, the highest activity being exhibited by Cu(dptaSS)(NO3)2 complex, which acts as antibiotic. In the antiproliferative tests (vs. T47D,L929 and BHK21/c13 cell lines) the best results were obtained with Cu(dptaSS)2+ and Cu(dienSS)2+. Electronic structure calculations gave for dptaSS and dienSS the higher negative charges on the N atoms. The counter-ions (Br-, NO3- and SO42-) play an important role by modulating the reagent's selectivity versus the bacteria [Gram(+) or Gram(-)], but they have no effect on the antiproliferative activity. PMID:18475868

  19. Electrochemistry of transition metal complexes of Schiff base compartmental ligands

    Microsoft Academic Search

    Piero Zanello; Sergio Tamburini; Pietro Alessandro Vigato; Gian Antonio Mazzocchin

    1984-01-01

    The electrochemical behaviour of a series of mononuclear and dinuclear complexes of dioxouranium(VI), nickel(II) and copper(II) ions with the Schiff base, H4fsalacen, derived from the condensation of 3-formylsalicylic acid and 1,2-diaminoethane, is reported.

  20. Synthesis, characterization and antibacterial properties of Schiff bases and Schiff base metal complexes derived from 2,3-diamino- pyridine

    Microsoft Academic Search

    Tagenine Jeewoth; Minu G. Bhowon; Henri Li Kam Wah

    1999-01-01

    New copper(II), zinc(II) and nickel(II) Schiff base complexes derived from 2,3-diaminopyridine (DAPY) and selected aldehydes, namely salicylaldehyde (SalH), 4-hydroxybenzaldehyde (4-OHBenz) and 4-nitrobenzaldehyde (4-NO2Benz), and one mixed Schiff base, DAPY-{4-OHBenz}{SalH} were prepared and characterized by a combination of elemental analyses, i.r. and n.m.r. spectra, and magnetic susceptibility measurements. The Schiff bases and some of the metal complexes display antibacterial properties.

  1. Trinuclear copper(II) complexes derived from Schiff-base ligands based on a 6-amino-6-deoxyglucopyranoside: structural and magnetic characterization.

    PubMed

    Roth, Arne; Becher, Jana; Herrmann, Carmen; Görls, Helmar; Vaughan, Gavin; Reiher, Markus; Klemm, Dieter; Plass, Winfried

    2006-12-11

    The trinuclear copper(II) complexes ([CuL1)(mu-ac)Cu(mu-ac)CuL1) (1) and ([CuL2)(mu-ac)Cu(mu-ac)CuL2) (2) of the tridentate aminosaccharide-derived Schiff-base ligands H2L1 [6-N-(salicylidene)amino-6-deoxy-1,2,3-tri-O-methyl-alpha-D-glucopyranoside] and H2L2 [6-N-(3,5-di-tert-butylsalicylidene)amino-6-deoxy-1,2,3-tri-O-methyl-alpha-D-glucopyranoside] were synthesized and structurally characterized. The trinuclear complex units can be described as two terminal copper-ligand moieties bridged by a central copper acetate moiety, with the Cu centers arranged in a triangular fashion. IR and UV/vis spectroscopic studies strongly indicate that the trinuclear structure is maintained in a methanolic solution. The temperature dependence of the magnetic susceptibility of both complexes shows a moderate antiferromagnetic coupling and can be well interpreted by applying a symmetric Cua-Cub-Cua' model with linear spin topology. The fit of the magnetic data affords coupling constants J of -34 and -24 cm(-1) for 1 and 2, respectively [H = -J(SaSb + SbSa')]. For mu-alkoxo-mu-acetato-bridged copper(II) complexes with a large dihedral angle between the adjacent coordination planes, as found in 1 and 2, such an antiferromagnetic coupling is unusual. However, density functional theory calculations of 2 using BP86, B3LYP*, and B3LYP density functionals confirmed a symmetric doublet ground state. PMID:17140212

  2. Synthesis and Characterisation of Complexes of Copper(II), Nickel(II) and Cobalt(II) with a Schiff Base Derivative of p-tert-Butylcalix[4]Arene

    Microsoft Academic Search

    Mustafa Yilmaz

    1998-01-01

    This article describes the synthesis of a Schiff base of p-terf-butylcalix[4]arene [H2L] in which the Schiff base unit bridges two opposite hydroxy groups of p-tert-butylcalix[4]arene. The synthesis of H2L has been achieved by refluxing p-tert-butylcalix[4]arene 1,3-diacetonyl (1) with 1,2-diaminoethane in ethanol. Metal-ligand (I : 1) complexes of this Schiff base with Co(II), Ni(II) and Cu(II) have been prepared fiom the

  3. Synthesis, CMC Determination, Antimicrobial Activity and Nucleic Acid Binding of A Surfactant Copper(II) Complex Containing Phenanthroline and Alanine Schiff-Base.

    PubMed

    Nagaraj, Karuppiah; Sakthinathan, Subramanian; Arunachalam, Sankaralingam

    2013-12-01

    A new water-soluble surfactant copper(II) complex [Cu(sal-ala)(phen)(DA)] (sal-ala = salicylalanine, phen = 1,10-phenanthroline, DA = dodecylamine), has been synthesized and characterized by physico-chemical and spectroscopic methods. The critical micelle concentration (CMC) values of this surfactant-copper(II) complex in aqueous solution were obtained from conductance measurements. Specific conductivity data (at 303, 308, 313. 318 and 323 K) served for the evaluation of the temperature-dependent CMC and the thermodynamics of micellization (?G(0)m, ?H(0)m and ?S(0)m). The interaction of this complex with nucleic acids (DNA and RNA) has been explored by using electronic absorption spectral titration, competitive binding experiment, cyclic voltammetry, circular dichroism (CD) spectra, and viscosity measurements. Electronic absorption studies have revealed that the complex can bind to nucleic acids by the intercalative binding mode which has been verified by viscosity measurements. The DNA binding constants have also been calculated (Kb?=?1.2?×?10(5) M(-1) for DNA and Kb?=?1.6?×?10(5) M(-1) for RNA). Competitive binding study with ethidium bromide (EB) showed that the complex exhibits the ability to displace the DNA-bound-EB indicating that the complex binds to DNA in strong competition with EB for the intercalative binding site. The presence of hydrophobic ligands, alanine Schiff-base, phenanthroline and long aliphatic chain amine in the complex were responsible for this strong intercalative binding. The surfactant-copper (II) complex was screened for its antibacterial and antifungal activities against various microorganisms. The results were compared with the standard drugs, amikacin(antibacterial) and ketokonazole(antifungal). PMID:24297573

  4. Metal complexes of bibracchial Schiff base macrocycles

    Microsoft Academic Search

    Simon R. Collinson; David E. Fenton

    1996-01-01

    This article discusses polynuclear metal complexes of Schiff base macrocycles and their potential application to the modelling of metallobiosites, in particular di- and tri-nuclear copper(II)-containing sites. A brief perspective of the area is presented and then the article addresses the development of pyridinyl-derived bibracchial (doubly pendant-armed) Schiff base macrocycles and their metal complexes. The cleft-like configurations of the complexes bear

  5. An antiferromagnetically coupled hexanuclear copper(II) Schiff base complex containing phenoxo and dicyanamido bridges: Structural aspects and magnetic properties

    Microsoft Academic Search

    Pritha Talukder; Shyamapada Shit; Ashok Sasmal; Stuart R. Batten; Boujemaa Moubaraki; Keith S. Murray; Samiran Mitra

    2011-01-01

    A novel hexanuclear complex [{(CuL)2Cu}2(?-dca)2](ClO4)2·2L?(1) (where H2L=(OH)C6H4C(CH3)N(CH2)3NC(CH3)C6H4(OH) or N,N?-bis(2-hydroxyacetophenone) propylenediimine and dca=N(CN)2? and L?=2-hydroxyacetophenone) has been synthesized and characterized by elemental analysis, UV–Vis, FT-IR spectroscopic and electrochemical methods. Single crystal X-ray structural characterization reveals a centrosymmetric nature of the complex unit, where the metal centers adopt distorted square-planar and distorted octahedral geometries. Structural analysis also reveals ?2-phenoxo bridges between terminal

  6. Fluorescent mixed ligand copper(ii) complexes of anthracene-appended Schiff bases: studies on DNA binding, nuclease activity and cytotoxicity.

    PubMed

    Jaividhya, Paramasivam; Ganeshpandian, Mani; Dhivya, Rajkumar; Akbarsha, Mohammad Abdulkadher; Palaniandavar, Mallayan

    2015-07-14

    A series of mixed ligand copper(ii) complexes of the type [Cu(L)(phen)(ACN)](ClO4)21-5, where L is a bidentate Schiff base ligand (N(1)-(anthracen-10-ylmethylene)-N(2)-methylethane-1,2-diamine (L1), N(1)-(anthracen-10-ylmethylene)-N(2),N(2)-dimethylethane-1,2-diamine (L2), N(1)-(anthracen-10-yl-methylene)-N(2)-ethylethane-1,2-diamine (L3), N(1)-(anthracen-10-ylmethylene)-N(2),N(2)-diethylethane-1,2-diamine (L4) and N(1)-(anthracen-10-ylmethylene)-N(3)-methylpropane-1,3-diamine (L5)) and phen is 1,10-phenanthroline, have been synthesized and characterized by spectral and analytical methods. The X-ray crystal structure of 5 reveals that the coordination geometry around Cu(ii) is square pyramidal distorted trigonal bipyramidal (?, 0.76). The corners of the trigonal plane of the geometry are occupied by the N2 nitrogen atom of phen, the N4 nitrogen atom of L5 and the N5 nitrogen of acetonitrile while the N1 nitrogen of phen and the N3 nitrogen of L5 occupy the axial positions with an N1-Cu1-N3 bond angle of 176.0(3)°. All the complexes display a ligand field band (600-705 nm) and three less intense anthracene-based bands (345-395 nm) in solution. The Kb values calculated from absorption spectral titration of the complexes (???*, 250-265 nm) with Calf Thymus (CT) DNA vary in the order 5 > 4 > 3 > 2 > 1. The fluorescence intensity of the complexes (520-525 nm) decreases upon incremental addition of CT DNA, which reveals the involvement of phen rather than the appended anthracene ring in partial DNA intercalation with the DNA base stack. The extent of quenching is in agreement with the DNA binding affinities and the relative increase in the viscosity of DNA upon binding to the complexes as well. Thus 5 interacts with DNA more strongly than 4 on account of the stronger involvement in hydrophobic DNA interaction of the anthracenyl moiety, which is facilitated by the propylene ligand backbone with chair conformation. The ability of complexes (100 ?M) to cleave DNA (pUC19 DNA) in 5 mM Tris-HCl/50 mM NaCl buffer at pH 7.1 in the absence of a reducing agent or light varies in the order 5 > 4 > 3 > 2 > 1, which is in conformity with their DNA binding affinities. Interestingly, cytotoxicity studies on the MCF-7 human breast cancer cell line show that the IC50 value of 5 is less than that of cisplatin for the same cell line, revealing that it can act as an effective cytotoxic drug in a time-dependent manner. PMID:26076117

  7. Synthesis and AntiBacterial\\/Catalytic Properties of Schiff Bases and Schiff Base Metal Complexes Derived from 2,3-Diaminopyridine

    Microsoft Academic Search

    T. Jeewoth; H. Li Kam Wah; Minu G. Bhowon; D. Ghoorohoo; K. Babooram

    2000-01-01

    Two new Schiff bases (1a)-(2a) derived from 2,3-diaminopyridine (DAPY) with pyrrole-2-carboxaldehyde (Pyrr) and 2-hydroxy-1-naphthaldehyde (NaphH), and new copper(II), iron(III), nickel(II), ruthenium(II) and zinc(II) complexes (1b)-(1e), (2b)-(2f) and (3b)-(3d) derived from these two new Schiff bases, and the bis-condensed Schiff base of 2,3-diaminopyridine and salicylaldehyde (SalH) were synthesized. They were characterized by a combination of elemental analyses, magnetic susceptibility measurements, IR

  8. Transition metal complexes of bidentate Schiff base ligands

    Microsoft Academic Search

    Mehmet Tümer; Cumali Çelik; Hüseyin Köksal; Selahattin Serin

    1999-01-01

    New Schiff base ligands derived from vanillin (HL1), 4-dimethylaminobenzaldehyde (HL2) and 3,5-di-t-butyl-4-hydroxybenzaldehyde (HL3) with N-(pyridyl)-3-methoxy-4-hydroxy-5-aminobenzylamine (2) and their copper(II), cobalt(II), nickel(II), oxovanadium(IV) and zinc(II) transition metal complexes have been synthesized and characterized by elemental analyses, electronic and i.r. spectra, molar conductance data and by 1H and 13C n.m.r. spectra. The results indicate that the ligands coordinate through azomethine nitrogen and

  9. 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.

  10. New nickel(II) and copper(II) complexes with unsymmetrical Schiff bases derived from (1R,2R)(-)cyclohexanediamine and the application of Cu(II) complexes for hybrid thin layers deposition.

    PubMed

    Barwiolek, M; Szlyk, E; Surdykowski, A; Wojtczak, A

    2013-08-28

    New unsymmetrical Schiff bases obtained by condensation of (1R,2R)(-)cyclohexanediamine with 2-hydroxy-3,5-di-tert-butylbenzaldehyde (3,5-(t)bba) and 2-hydroxy-3-methoxybenzaldehyde (3-metoxba) or 2-hydroxy-5-nitrobenzaldehyde (5-nba) and 2-hydroxyacetophenone (hacphen) were used for the synthesis of Cu(ii) and Ni(ii) complexes. The ligands and complexes were characterized by circular dichroism (CD), UV-vis, IR, (1)H (NOE diff) (ligand) and (13)C NMR (ligand) spectra. The X-ray crystal structures solved for Ni(II)(1R,2R)(-)chxn(3,5-(t)bba)(hacphen) exhibit distortion of the coordination sphere towards tetrahedral in the solid phase. The complex crystallized in the orthorhombic non-centrosymmetric P2(1)2(1)2(1) space group. Thin layers of copper(II) complexes were deposited on Si(111) by a spin coating technique and characterized by scanning electron microscopy (SEM/EDS), atomic force microscopy (AFM) and fluorescence spectroscopy. Layer deposition conditions were studied and optimal parameters were found (1500 rpm, time 30 s). For copper(ii) layers the most intensive fluorescence band from intraligand transition at 514 nm was observed. CD spectra of complexes in MeCN suggest the tetrahedral distortion from the square planar geometry of the central ion of the coordination sphere in solution. The (1)H NMR NOE diff. spectra of ligands were measured and the positions of the nearest hydrogen atoms in the cyclohexane and aromatic rings were discussed. PMID:23831645

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

    Microsoft Academic Search

    Sulekh Chandra; X. Sangeetika

    2004-01-01

    A new macrocylic Schiff base 1,2,5,6,8,11-hexaazacyclododeca-7,12-dithione-2,4,8,10-tetraene(H2L4) containing thiosemicarbazone moiety is readily prepared and characterized for the first time with fairly good yield. Macrocylic ligand (H2L4) is prepared from the mesocyle 6-ethoxy-4-thio-2,3,5-triazine(H2L3) in ethanol with copper chloride acting as template using high dilution technique. The complexes of macrocylic ligand with a general composition M(H2L4)X2 [where M=Cu(II) or Ni(II); H2L4=1,2,5,6,8,11-hexaazacyclo dodeca-7,12-dithione-2,4,8,10-tetraene; X=

  12. 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 ?-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.

  13. 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.

  14. Catalytic activities of Schiff base transition metal complexes

    Microsoft Academic Search

    K. C. Gupta; Alekha Kumar Sutar

    2008-01-01

    Many Schiff base complexes of metal ions show high catalytic activity. Chiral Schiff base complexes are more selective in various reactions such as oxidation, hydroxylation, aldol condensation and epoxidation. The catalytic activity of metal complexes of binaphthyl, binaphthol and their combinations with salen Schiff base is presented in this review. The pyridyl bis(imide) and pyridine bis(imine) complexes of cobalt(II), iron(II)

  15. Syntheses, crystal structure and biological evaluation of Schiff bases and copper complexes derived from 4-formylpyrazolone

    NASA Astrophysics Data System (ADS)

    Joseph, V. A.; Pandya, J. H.; Jadeja, R. N.

    2015-02-01

    Two new pyrazolone based Schiff base ligands 4-((2,4-dimethylphenylimino)methyl)-4,5-dihydro-3-methyl-1-p-tolyl-1H-pyrazol-5-ol [PTPMP-ME] and 4-((3,4-difluorophenylimino)methyl)-4,5-dihydro-3-methyl-1-p-tolyl-1H-pyrazol-5-ol [PTPMP-F] were synthesized. Using these Schiff base ligands two new Copper(II) complexes, [Cu(PTPMP-ME)2] (1) and [Cu(PTPMP-F)2] (2) were synthesized. The ligands and their copper complexes were characterized by IR, 1H NMR, mass, UV-Visible spectroscopy, molar conductivity and magnetic measurement. The molecular geometry of Schiff base ligand PTPMP-ME and copper complexes were determined by single-crystal X-ray analysis. On the basis of single crystal X-ray analysis and spectroscopic techniques, square planar geometry of the complexes was proposed. The Schiff base ligands and their metal complexes were tested for antimicrobial activity against Gram-positive bacteria; Staphylococcus aureus and Bacillus subtilis and Gram-negative bacteria; Escherichia coli and Pseudomonas aeruginosa.

  16. Schiff Base Complexes of Boron: Boron Complexes of Schiff Bases of 2,4-Pentanedione

    Microsoft Academic Search

    H. B. Singh; J. P. Tandon

    1978-01-01

    Tetra-coordinated diacetoxy-boron Schiff base derivatives of the type (AcO)2B(SB) (where SB is the anion of the corresponding monofunctional bidentate Schiff base, SBH) have been synthesized in almost quantitative yields and in a state of sufficient purity by the equimolar ratio reactions of boric acid and Schiff bases in acetic anhydride medium. Even on mixing the reactants in higher molar ratio

  17. Synthesis and spectroscopic studies of new binuclear transition metal complexes of Schiff bases derived from 4,6-diacetylresorcinol

    Microsoft Academic Search

    Adel A. A. Emara; Omima M. I. Adly

    2007-01-01

    Two new series of copper(II), nickel(II), cobalt(II), zinc(II), iron(III), chromium(III), vanadyl(IV) and uranyl(VI) complexes\\u000a with two bifunctional tridentate Schiff base, H4L1 and H2L2 ligands have been prepared. The Schiff base, H4L1 and H2L2, ligands were synthesized by the condensation of 4,6-diacetylresorcinol with o-aminophenol or o-phenylenediamine. The ligands are either di- or tetra-basic with two symmetrical sets of either OON or

  18. Copper(II), Nickel(II), Oxovanadium(IV) and Dioxouranium(VI) Complexes of Novel Asymmetric Tetradentate Schiff Base Ligands Derived from 6Methyl3Formyl4Hydroxy2-(1H)-Quinolone. Part V

    Microsoft Academic Search

    Saied M. E. Khalil; Mahmoud M. Mashaly; Adel A. A. Emara

    1995-01-01

    The novel, half-unit ligand obtained by the single condensation of 6-methyl-3-formyl-4-hydroxy-2-(1H)-quinolone and p-phenylenediamine, was condensed with either acetylacetone or salicylaldehyde to yield novel, asymmetric tetradentate Schiff base ligands, H2La and H2Lb, respectively. The reactions of the ligands with Cu, Ni, VO and UO2 salts yielded complexes of the general formula [L2M2 nH2O, except that of the uranyl complex of the

  19. Synthesis, characterization and antibacterial activity of a tridentate Schiff base derived from cephalothin and sulfadiazine, and its transition metal complexes.

    PubMed

    Anacona, J R; Noriega, Natiana; Camus, Juan

    2015-02-25

    Metal(II) coordination compounds of a cephalothin Schiff base (H2L) derived from the condensation of cephalothin antibiotic with sulfadiazine were synthesized. The Schiff base ligand, mononuclear [ML(H2O)3] (M(II)=Mn,Co,Ni,Zn) complexes and magnetically diluted dinuclear copper(II) complex [CuL(H2O)3]2 were characterized by several techniques, including elemental and thermal analysis, molar conductance and magnetic susceptibility measurements, electronic, FT-IR, EPR and (1)H NMR spectral studies. The cephalothin Schiff base ligand H2L behaves as a dianionic tridentate NOO chelating agent. The biological applications of complexes have been studied on two bacteria strains (Escherichia coli and Staphylococcus aureus) by agar diffusion disc method. PMID:25194315

  20. Structural and spectroscopic characterization of a cationic aquanitrato copper(II) complex with the tetradentate Schiff-base ligand N,N?-bis[1–(2–pyridyl)ethylidene]ethane-1,2–diamine

    Microsoft Academic Search

    Sotiris Gourbatsis; Nick Hadjiliadis; Spyros P. Perlepes; Achilleas Garoufis; Ian S. Butler

    1998-01-01

    Cu(NO3)2·3H2O reacts with 1 equiv. of the tetradentate Schiff base N,N'-bis[1–(2–pyridyl)ethylidene]ethane-1,2–diamine (LA) in refluxing acetone to yield the [CuLA(ONO2)(H2O)](NO3) complex in ca. 80% yield. The structure of this salt has been determined by single-crystal X-ray crystallography. The copper is six-coordinated with the LA ligand in the equatorial plane and weakly bonded aqua and nitrato ligands above and below this plane.

  1. A novel copper(II)-Schiff base complex containing pyrrole ring: Synthesis, characterization and its modified electrodes applied in oxidation of aliphatic alcohols

    E-print Network

    Boyer, Edmond

    1 A novel copper(II)-Schiff base complex containing pyrrole ring: Synthesis, characterization 35042 Rennes Cedex, France. Abstract A new copper(II) complex Cu(II)-L containing N2O2 donor atoms has of copper acetate monohydrate. It was characterized by spectroscopic methods such as FT-IR, UV­vis, mass

  2. Dinuclear metal complexes of Schiff base ligands as catalysts for oxidation and epoxidation reactions

    Microsoft Academic Search

    P. S. Zacharias; B. Srinivas; H. Aneetha

    1995-01-01

    Dinuclear copper(II) complexes (Cu2 LnCl3), nickel(II) complexes (Ni2 LnCl3) and cobalt(II) complexes (Co2L\\u000a 2\\u000a n\\u000a Cl2) from Schiff base ligands are synthesised, characterised and used as catalysts for oxidation of 3,5-DTBC to 3,5-DTBQ. (Cu2LnCl3) are found to be more efficient than the other complexes. Dinuclear iron(III) complexes of composition (Fe2L2Cl2) and ruthenium (III) complexes of composition Ru2L\\u000a 2\\u000a n\\u000a Cl6(PPh3)2

  3. Metal complexes of ONO donor Schiff base ligand as a new class of bioactive compounds; Synthesis, characterization and biological evolution

    NASA Astrophysics Data System (ADS)

    Kumar Naik, K. H.; Selvaraj, S.; Naik, Nagaraja

    2014-10-01

    Present work reviews that, the synthesis of (E)-N";-((7-hydroxy-4-methyl-2-oxo-2H-chromen-8-yl)methylene)benzohydrazide [L] ligand and their metal complexes. The colored complexes were prepared of type [M2+L]X2, where M2+ = Mn, Co, Ni, Cu, Sr and Cd, L = (7-hydroxy-4-methyl-2-oxo-2H-chromen-8-yl)methylene)benzohydrazide, X = Cl-. Ligand derived from the condensation of 8-formyl-7-hydroxy-4-methylcoumarin and benzohydrazide in the molar ratio 1:1 and in the molar ratio 1:2 for metal complexes have been prepared. The chelation of the ligand to metal ions occurs through the both oxygen groups, as well as the nitrogen atoms of the azomethine group of the ligand. Reactions of the Schiff base ligand with Manganese(II), Cobalt(II), Nickel(II), Copper(II), Strontium(II), and Cadmium(II) afforded the corresponding metal complexes. The structures of the obtained ligand and their respective metal complexes were elucidated by infra-red, elemental analysis, Double beam UV-visible spectra, conductometric measurements, magnetic susceptibility measurements and also thermochemical studies. The metal complex exhibits octahedral coordination geometrical arrangement. Schiff base ligand and their metal complexes were tested against antioxidants, antidiabetic and antimicrobial activities have been studied. The Schiff base metal complexes emerges effective ?-glucosidase inhibitory activity than free Schiff base ligand.

  4. Metal complexes of ONO donor Schiff base ligand as a new class of bioactive compounds: synthesis, characterization and biological evolution.

    PubMed

    Kumar Naik, K H; Selvaraj, S; Naik, Nagaraja

    2014-10-15

    Present work reviews that, the synthesis of (E)-N'-((7-hydroxy-4-methyl-2-oxo-2H-chromen-8-yl)methylene)benzohydrazide [L] ligand and their metal complexes. The colored complexes were prepared of type [M(2+)L]X2, where M(2+)=Mn, Co, Ni, Cu, Sr and Cd, L=(7-hydroxy-4-methyl-2-oxo-2H-chromen-8-yl)methylene)benzohydrazide, X=Cl(-). Ligand derived from the condensation of 8-formyl-7-hydroxy-4-methylcoumarin and benzohydrazide in the molar ratio 1:1 and in the molar ratio 1:2 for metal complexes have been prepared. The chelation of the ligand to metal ions occurs through the both oxygen groups, as well as the nitrogen atoms of the azomethine group of the ligand. Reactions of the Schiff base ligand with Manganese(II), Cobalt(II), Nickel(II), Copper(II), Strontium(II), and Cadmium(II) afforded the corresponding metal complexes. The structures of the obtained ligand and their respective metal complexes were elucidated by infra-red, elemental analysis, Double beam UV-visible spectra, conductometric measurements, magnetic susceptibility measurements and also thermochemical studies. The metal complex exhibits octahedral coordination geometrical arrangement. Schiff base ligand and their metal complexes were tested against antioxidants, antidiabetic and antimicrobial activities have been studied. The Schiff base metal complexes emerges effective ?-glucosidase inhibitory activity than free Schiff base ligand. PMID:24858195

  5. Oxidative peptide /and amide/ formation from Schiff base complexes

    NASA Technical Reports Server (NTRS)

    Strehler, B. L.; Li, M. P.; Martin, K.; Fliss, H.; Schmid, P.

    1982-01-01

    One hypothesis of the origin of pre-modern forms of life is that the original replicating molecules were specific polypeptides which acted as templates for the assembly of poly-Schiff bases complementary to the template, and that these polymers were then oxidized to peptide linkages, probably by photo-produced oxidants. A double cycle of such anti-parallel complementary replication would yield the original peptide polymer. If this model were valid, the Schiff base between an N-acyl alpha mino aldehyde and an amino acid should yield a dipeptide in aqueous solution in the presence of an appropriate oxidant. In the present study it is shown that the substituted dipeptide, N-acetyl-tyrosyl-tyrosine, is produced in high yield in aqueous solution at pH 9 through the action of H2O2 on the Schiff-base complex between N-acetyl-tyrosinal and tyrosine and that a great variety of N-acyl amino acids are formed from amino acids and aliphatic aldehydes under similar conditions.

  6. Synthesis, characterization, and biological evaluation of new polyester containing Schiff base metal complexes

    Microsoft Academic Search

    Nahid Nishat; Sumaiya Hasnain; Tansir Ahmad; Asma Parveen

    The production of new biocidal polyester Schiff base metal complexes [PESB–M(II)] via polycondensation reaction between chelated\\u000a Schiff base diol and adipoyl chloride is reported. The resulting polyesters were characterized by physico-chemical and spectroscopic\\u000a methods. The analytical data of all the synthesized polyesters were found to be in good agreement with 1:1 molar ratio of\\u000a chelated Schiff base diol to adipoyl

  7. Newer mixed ligand Schiff base complexes from aquo-N-(2?-hydroxy acetophenone) glycinatocopper(II) as synthon: DFT, antimicrobial activity and molecular docking study

    NASA Astrophysics Data System (ADS)

    Pramanik, Harun A. R.; Das, Dharitri; Paul, Pradip C.; Mondal, Paritosh; Bhattacharjee, Chira R.

    2014-02-01

    Synthesis of a series of newer mixed ligand copper(II) complexes of aminoacid Schiff base of the type [CuL(X)] (L = N-(2?-hydroxy acetophenone) glycinate, X = imidazole (im) 2, benzimidazole (benz) 3, pyridine (py) 4, hydrazine (hz) 5,8-hydroxyquinoline (8-hq) 6, pyrrolidine (pyrr) 7, piperidine (pip) 8, and nicotinamide (nic) 9) have been accomplished from the interaction of an aquated Schiff base complex, [CuL(H2O)]·H2O, 1 with some selected neutral nitrogen-donor ligands. The copper(II) Schiff base complex, [CuL(H2O)]·H2O, L = N-(2?-hydroxy acetophenone) glycinate was synthesized from the reaction of glycine and 2? hydroxy acetophenone and copper(II) acetate. The compounds were characterised by elemental analysis, spectral, magnetic and thermal studies. The density functional theory calculations were performed using LANL2DZ and 6-311 G(d, p) basis sets with B3LYP correlation functional to ascertain the stable electronic structure, HOMO-LUMO energy gap, chemical hardness and dipole moment of the mixed ligand complexes. A distorted square planar geometry has been conjectured for the complexes. Antibacterial activities of the ligand and its metal complexes have been tested against selected gram-positive and gram-negative strains and correlated with computational docking scores.

  8. Synthesis, spectroscopic studies and inhibitory activity against bactria and fungi of acyclic and macrocyclic transition metal complexes containing a triamine coumarine Schiff base ligand.

    PubMed

    Abou-Hussein, A A; Linert, Wolfgang

    2015-04-15

    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, (1)H-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, (1)H-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. PMID:25681806

  9. 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.

  10. Epoxidation of cyclohexene with K10-montmorillonite and Schiff-base macrocyclic copper complexes

    Microsoft Academic Search

    Masoud Salavati-Niasari; Elham Zamani; Mehdi Bazarganipour

    2007-01-01

    Copper(II) complexes of 12- and 13-membered diaza dioxa Schiff-base macrocyclic ligand, 1,4-diaza-7,10-dioxacyclododeca-1,3-diene, H2[12]1,3-dieneN2O2; 2,3-dimethyl-1,4-diaza-7,10-dioxacyclododeca-1,3-diene, (CH3)2[12]1,3-dieneN2O2; 2,3-diphenyl-1,4-diaza-7,10-dioxacyclododeca-1,3-diene, (C6H5)2[12]1,3-dieneN2O2; 2,4-dimethyl-1,5-diaza-8,11-dioxacyclotrideca-1,4-diene, (CH3)2[13]1,4-dieneN2O2; 2,4-diphenyl-1,5-diaza-8,11-dioxacyclotrideca-1,4-diene, (C6H5)2[13]1,4-dieneN2O2 were entrapped into an montmorillonite-K10 (denoted as K10) by simultaneous\\/pillaring encapsulation method. In this method the simultaneous encapsulation also occurred but the complex, also dissolved in methanol, was added to the clay dispersion. All materials were characterized by FTIR,

  11. Novel Schiff-base complexes of methyltrioxorhenium (VII) and their performances in epoxidation of cyclohexene

    Microsoft Academic Search

    Chuan-Jiang Qiu; Yue-Cheng Zhang; Yu Gao; Ji-Quan Zhao

    2009-01-01

    Methyltrioxorhenium (MTO) forms complexes with Schiff-bases derived from 2-pyridinecarboxaldehyde and amines. These complexes were isolated and fully characterized by NMR, IR, UV–Vis, EA, MS. Two were analyzed by X-ray crystallography, which showed that the compounds display distorted octahedral geometry in the solid state with a trans-position of Schiff-base ligand. The characterized results indicated that the more Lewis basic the ligand

  12. Synthesis, potentiometric and antimicrobial studies on metal complexes of isoxazole Schiff bases

    Microsoft Academic Search

    Y. Prashanthi; K. Kiranmai; N. J. P. Subhashini; Shivaraj

    2008-01-01

    The metal complexes of Cu(II), Ni(II) and Co(II) with Schiff bases of 3-(2-hydroxy-3-ethoxybenzylideneamino)-5-methyl isoxazole [HEBMI] and 3-(2-hydroxy-5-nitrobenzylidene amino)-5-methyl isoxazole [HNBMI] which were obtained by the condensation of 3-amino-5-methyl isoxazole with substituted salicylaldehydes have been synthesized. Schiff bases and their complexes have been characterized on the basis of elemental analysis, magnetic moments, molar conductivity, thermal analysis and spectral (IR, UV, NMR

  13. Synthesis, spectroscopic, DNA cleavage and antibacterial activity of binuclear schiff base complexes

    Microsoft Academic Search

    N. Mahalakshmi; R. Rajavel

    The binuclear Schiff base complexes are formed newly using different transition metals at their stable oxidation state as Cu(II), Ni(II), and VO(II). 3,3?,4,4?-tetraminobiphenyl and 2-aminobenzaldehyde were condensed to form a new Schiff base ligand having an two N4 group responsible for better chelating to the metal centers. The ligand and their complexes have been established by analytical, spectral and electrochemical

  14. Interaction of a copper(II)-Schiff base complexes with calf thymus DNA and their antimicrobial activity.

    PubMed

    Sabolová, D; Kožurková, M; Plichta, T; Ondrušová, Z; Hudecová, D; Simkovi?, M; Paulíková, H; Valent, A

    2011-03-01

    The interaction of a copper complexes containing Schiff bases with calf thymus (CT) DNA was investigated by spectroscopic methods. UV-vis, fluorescence and CD spectroscopies were conducted to assess their binding ability with CT DNA. The binding constants K have been estimated from 0.8 to 9.1×10(4) M(-1). The percentage of hypochromism is found to be over 70% (from spectral titrations). The results showed that the copper(II) complexes could bind to DNA with an intercalative mode. Synergic action of Cu(II) complexes with ascorbic acid against Candida albicans induced the generation of free radicals and increased (more than 60 times) antimicrobial effect of these complexes. PMID:21145345

  15. Mn(II) and Cu(II) complexes of a bidentate Schiff's base ligand: Spectral, thermal, molecular modelling and mycological studies

    NASA Astrophysics Data System (ADS)

    Tyagi, Monika; Chandra, Sulekh; Tyagi, Prateek

    2014-01-01

    Complexes of manganese(II) and copper(II) of general composition M(L)2X2 have been synthesized [L = 2-acetyl thiophene thiosemicarbazone and X = Cl- and NO3-]. The elemental analysis, molar conductance measurements, magnetic susceptibility measurements, mass, IR, UV, NMR and EPR spectral studies of the compounds led to the conclusion that the ligand acts as a bidentate manner. The Schiff's base ligand forms hexacoordinated complexes having octahedral geometry for Mn(II) and tetragonal geometry for Cu(II) complexes. The thermal studies suggested that the complexes are more stable as compared to ligand. In molecular modelling the geometries of Schiff's base and metal complexes were fully optimized with respect to the energy using the 6-31g(d,p) basis set. The mycological studies of the compounds were examined against the plant pathogenic fungi i.e. Rhizoctonia bataticola, Macrophomina phaseolina, Fusarium odum.

  16. Advancement in stereochemical aspects of Schiff base metal complexes

    Microsoft Academic Search

    Shoichiro Yamada

    1999-01-01

    The object of the paper is to look back upon the development of coordination chemistry in the past several decades, during the career of the author, and possibly see how and through what accomplishments the present coordination chemistry has been built up. For the sake of space available, the paper will focus on the stereochemical aspects of Schiff base metal

  17. Metal complexes of polyaza and polyoxaaza Schiff base macrocycles

    Microsoft Academic Search

    Wanda Radecka-Paryzek; Violetta Patroniak; Jerzy Lisowski

    2005-01-01

    This review describes the development on the coordination chemistry of multidentate Schiff base macrocycles with an emphasis on the author's contribution to the field. Particular attention is paid to effectiveness of metal ions – especially lanthanides – in supramolecular self-assembly of the components leading to organized structures. The article is focused on the design, template synthesis and characterization of the

  18. Synthesis and physico-chemical and biological studies on ruthenium (III) complexes with Schiff bases derived from aminocarboxylic acids

    Microsoft Academic Search

    Vinod K. Sharma; Om P. Pandey; Soumitra K. Sengupta

    1987-01-01

    Summary Ruthenium(III) complexes of types [Ru(L)3], [Ru(L')Cl(H2O)2], [Ru(L?)Cl2]n, [Ru(L?)Cl(H2O)]n(LH =Schiff bases derived from anthranilic acid and benzaldehyde, acetophenone, vanillin, cinnamaldehyde orm-hydroxyacetophenone; L'H2=Schiff bases derived from anthranilic acid and salicylaldehyde oro-hydroxyacetophenone; L?H=Schiff bases derived fromp-aminobenzoic acid and benzaldehyde, acetophenone, vanillin, cinnamaldehyde orm-hydroxyacetophenone; L?H2=Schiff bases derived fromp-aminobenzoic acid and salicylaldehyde oro-hydroxyacetophenone) have been synthesized and characterized on the basis of elemental analyses,

  19. The Superoxide Dismutase Mimics of Metal Complexes of Schiff-bases

    Microsoft Academic Search

    Li Jinfang; Tu Shujie; Zhou Yinzhuang

    The design and application of the synthesis of low molecular weight metal complexes containing Cu, Zn, Mn etc. as SOD mimics have received considerable attention during the last decades. Large number of the complexes of Cu, Zn, Mn etc with various donor ligands have been characterized as • 2 O promising models of the enzyme, including Schiff-base ligands.The results showed

  20. Biological activity studies on metal complexes of novel tridentate Schiff base ligand. Spectroscopic and thermal characterization

    Microsoft Academic Search

    Gehad G. Mohamed; M. M. Omar; Amr A. Ibrahim

    2009-01-01

    Metal complexes of novel Schiff base (HL) ligand, prepared via condensation of 4-aminoantipyrine and 2-aminophenol, are prepared. The ligand is characterized based on elemental analysis, mass, IR and 1H NMR spectra. Metal complexes are reported and characterized based on elemental analyses, IR, 1H NMR, solid reflectance, magnetic moment, molar conductance, ESR spectra and thermal analyses (TG, DTG and DTA). From

  1. Transition metal complexes with Schiff-base ligands: 4-aminoantipyrine based derivatives–a review

    Microsoft Academic Search

    N. Raman; S. Johnson Raja; A. Sakthivel

    2009-01-01

    The survey highlights structural properties and biological studies of transition metal complexes derived from 4-aminoantipyrine. The most important results of extensive studies (syntheses, spectral, magnetic, redox, structural characteristics, antimicrobial and DNA cleavage) of the metal complexes with heterocyclic Schiff bases of 4-aminoantipyrine with some aldehydes and oximes are reviewed.

  2. Designing, structural elucidation and comparison of the cleavage ability of metal complexes containing tetradentate Schiff bases

    Microsoft Academic Search

    N. Raman; A. Sakthivel; J. Dhaveethu Raja; K. Rajasekaran

    2008-01-01

    New N2O2 donor type Schiff bases have been designed and synthesized by condensing acetylaceto-4-aminoantipyrine\\/acetoacetanilido-4-aminoantipyrine\\u000a with 2-amino benzoic acid in ethanol. Solid metal complexes of the Schiff bases with Cu(II), Ni(II), Co(II), Mn(II), Zn(II),\\u000a VO(IV), Hg(II) and Cd(II) metal ions were synthesized and characterized by elemental analyses, magnetic susceptibility, molar\\u000a conduction, FAB Mass, IR, UV-Vis., 1H NMR, and ESR spectral studies.

  3. Metal complexes of chiral binaphthyl Schiff-base ligands and their application in stereoselective organic transformations

    Microsoft Academic Search

    Chi-Ming Che; Jie-Sheng Huang

    2003-01-01

    Condensations of aromatic aldehydes with 2,2?-diamino-1,1?-binaphthyl or 2-amino-2?-hydroxy-1,1?-binaphthyl afford various chiral binaphthyl Schiff-base ligands, the most common of which are potentially tetradentate with a N2O2 donor set. The chiral binaphthyl Schiff-base ligands have been shown to form stable complexes with metal ions of Al(III), Ti(IV), Cr(III), Mn(II)\\/Mn(III), Fe(II)\\/Fe(III), Co(II)\\/Co(III), Ni(II), Cu(II), Zn(II), Y(III), Zr(IV), Ru(II), and Pd(II); some of such

  4. Spectrometric study of tautomeric and protonation equilibria of o-vanillin Schiff base derivatives and their complexes with Cu(II)

    NASA Astrophysics Data System (ADS)

    Gali?, Nives; Cimerman, Zvjezdana; Tomiši?, Vladislav

    2008-12-01

    Electronic absorption and emission properties of a series of Schiff bases derived from 2-hydroxy-3-methoxybenzaldehyde and 2-aminopyridine, 2,3-diaminopyridine, 2,6-diaminopyridine, or 3-aminomethylpyridine were studied in solvents of different polarities. The interconversion of the enolimine to the ketoamine tautomeric form was observed for compound 1, 6-methoxy-2-(3-pyridylmethyliminomethyl)phenol, and the corresponding equilibrium constant was estimated in several solvents. Protonation constants of all the investigated compounds were determined spectrophotometrically in the methanol/water 1/4 system. The effect of copper(II) ions on absorption and on the emission spectra of these ligands was examined in the buffered dioxane/water 1/1 system (pH 5.8). Strong complexation of Cu(II) and formation of a 1:1 complex were observed for the bis-Schiff base derived from 2,3-diaminopyridine. The complex of copper(II) with compound 1 was isolated and characterized by elemental analysis, magnetic susceptibility measurement, UV-vis and IR spectrometry.

  5. DNA interaction studies of d and d metal complexes having Schiff base and polypyridyl ligands

    Microsoft Academic Search

    Krishnan Pothiraj; Thanasekaran Baskaran; Natarajan Raman

    2012-01-01

    Four mononuclear complexes of Cu(II) and Zn(II) having a Schiff base ligand and 1,10-phenanthroline\\/2,2'-bipyridine have been synthesized and characterized. From electronic spectral and magnetic susceptibility data, octahedral geometry has been proposed for the complexes. DNA binding behaviors of these complexes are studied by absorption titration, electrochemical and viscosity methods. The results indicate that the complexes bind to calf thymus DNA

  6. Effect of the Schiff base complex diaqua-(N-salicylidene-l-glutamato)copper(II) monohydrate on human tumor cells.

    PubMed

    Konarikova, Katarina; Andrezalova, Lucia; Rapta, Peter; Slovakova, Marianna; Durackova, Zdenka; Laubertova, Lucia; Gbelcova, Helena; Danisovic, Lubomir; Bohmer, Daniel; Ruml, Tomas; Sveda, Martin; Zitnanova, Ingrid

    2013-12-01

    The aim of our study was to estimate cytostatic/cytotoxic activity of the copper(II) Schiff base complex of the composition [Cu(N-salicylidene-l-glutamato)(H2O)2]·H2O, further Cu(SG-L)H2O, against human colon carcinoma cell line HT-29, as well as to determine type of cell death and to find out the molecular mechanism of apoptosis induced by this complex. Two highest concentrations (50, 100 µmol/l) of the complex showed a strong cytotoxic activity against human colon carcinoma cells HT-29 after 72 h of influence. Other concentrations had a cytostatic activity. Unchelated copper(II) ions and free ligands had no effect on the cell growth. Cu(SG-L)H2O preferentially reduced cancer cell viability compared to healthy cells (NIH-3T3). Cu(SG-L)H2O induced apoptosis of cells HT-29 at all concentrations used (1-100 µmol/l) after 48 h of influence. Apoptosis was carried out by the mitochondrial pathway with active caspases 3 and 9. By the spin-trapping technique combined with electron paramagnetic resonance we found that our complex is photochemically stable in aqueous systems and does not exhibit radical-scavenging activity when 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonate) cation radical was used as an oxidant. The complex exhibits a strong prooxidant property in the initial stages of thermal decomposition of K2S2O8 in water solutions leading to the massive production of (·)OH radicals. Therefore, this complex could strongly participate in anticancer action via a free radical mechanism. PMID:24113525

  7. Studies on Some Transition Metal Complexes of Schiff Bases Derived from Quinoxaline?2?carboxaldehyde

    Microsoft Academic Search

    S. Mayadevi; Preetha G. Prasad; K. K. Mohammed Yusuff

    2003-01-01

    Two series of transition metal complexes of Schiff bases derived from quinoxaline?2?carboxaldehyde with semicarbazide (QSC) and furfurylamine (QFA) were synthesised and characterised by elemental analyses, molar conductance and magnetic susceptibility measurements, IR, electronic and EPR spectral studies. The QSC complexes have the general formula [M(QSC)Cl2]. A tetrahedral structure has been assigned for the Mn(II), Co(II) and Ni(II) complexes and a

  8. Transition Metal(II) Complexes with Cefotaxime-Derived Schiff Base: Synthesis, Characterization, and Antimicrobial Studies

    PubMed Central

    Amzoiu, Emilia; Spînu, Cezar Ionu?

    2014-01-01

    New [ML2(H2O)2] complexes, where M?=?Co(II), Ni(II), Cu(II), and Zn(II) while L corresponds to the Schiff base ligand, were synthesized by condensation of cefotaxime with salicylaldehyde in situ in the presence of divalent metal salts in ethanolic medium. The complexes were characterized by elemental analyses, conductance, and magnetic measurements, as well as by IR and UV-Vis spectroscopy. The low values of the molar conductance indicate nonelectrolyte type of complexes. Based on spectral data and magnetic moments, an octahedral geometry may be proposed for Co(II), Ni(II), and Zn(II) complexes while a tetragonal geometry for Cu(II) complex. Molecular structure of the Schiff base ligand and its complexes were studied using programs dedicated to chemical modeling and quantomolecular calculation of chemical properties. All the synthesized complexes were tested for in vitro antibacterial activity against some pathogenic bacterial strains, namely Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Bacillus subtilis, and Staphylococcus aureus. The MIC values shown by the complexes against these bacterial strains revealed that the metal complexes possess superior antibacterial activity than the Schiff base. PMID:24688454

  9. Synthesis, Characterization and Biocidal Activities of Some Schiff Base Metal Complexes

    PubMed Central

    Neelakantan, M. A.; Esakkiammal, M.; Mariappan, S. S.; Dharmaraja, J.; Jeyakumar, T.

    2010-01-01

    Some new mixed ligand complexes (1-5) of type ML'B (M(II)=Mn(II), Co(II), Ni(II), Cu(II) and Zn(II); HL'= o-vanillidene-2-aminobenzothiazole; B= 1,10-phenanthroline) and Schiff base metal complexes of types (ML2") (6-10) and (M2L") (11-15) (HL"= o-vanillidene-2-amino-N-(2-pyridyl)-benzene sulfonamide) were synthesized and characterized by elemental analysis and spectral (IR, 1H NMR and 13C NMR) studies. The free ligands and their metal complexes have been screened for their in vitro biological activities against bacteria, fungi and yeast. The metal complexes show more potent activities compared with Schiff base ligands. PMID:20838526

  10. Synthesis, crystal structure and urease inhibitory activities of Schiff base metal complexes

    Microsoft Academic Search

    Da-Hua Shi; Zhong-Lu You; Chen Xu; Qiang Zhang; Hai-Liang Zhu

    2007-01-01

    Six new transition metal complexes (1–6) with Schiff base were synthesized and crystallographically characterized. Their urease inhibitory activities were evaluated. Three of them showed potent inhibitions against jack bean urease. Mn(II) complex (2) possessed the best jbU inhibitory activity with IC50 of 8.30±0.93?M, which was much better than those of the corresponding ligand and control ion. The investigation on the

  11. A dinuclear cadmium(II) Schiff base thiocyanato complex: crystal structure and fluorescence.

    PubMed

    Shit, Shyamapada; Sankolli, Ravish; Guru Row, Tayur N

    2014-01-01

    A new dinuclear cadmium(II) complex, [Cd(L)(NCS)]2 (1) has been synthesized using a potentially tetradentate Schiff base ligand HL, 2-((E)-(2-(diethylamino)ethylimino)methyl)-6-methoxyphenol, obtained by the condensation of 2-diethylaminoethylamine and o-vanillin, and characterized by different physicochemical techniques. Crystal structure of the title complex was unambiguously established by single crystal X-ray diffraction which reveals that metal centers are connected by bridging phenolato and chelating methoxy oxygen atoms of the coordinating Schiff bases and embedded in severely distorted octahedral geometries. Fluorescence properties of the ligand and its complex, studied at room temperature indicate that later may serve as strong fluorescent emitter. PMID:24664327

  12. Synthesis, characterization, and biological evaluation of Schiff base-platinum(II) complexes

    NASA Astrophysics Data System (ADS)

    Shiju, C.; Arish, D.; Bhuvanesh, N.; Kumaresan, S.

    2015-06-01

    The platinum complexes of Schiff base ligands derived from 4-aminoantipyrine and a few substituted aldehydes were synthesized and characterized by elemental analysis, mass, 1H NMR, IR, electronic spectra, molar conductance, and powder XRD. The structure of one of the ligands L5 was confirmed by a single crystal XRD analysis. The Schiff base ligand crystallized in the triclinic, space group P-1 with a = 7.032(2) ?, b = 9.479(3) ?, c = 12.425(4) ?, ? = 101.636(3)°, ? = 99.633(3)°, ? = 94.040(3)°, V = 795.0(4) ?3, Z = 2, F(0 0 0) = 352, Dc = 1.405 mg/m3, ? = 0.099 mm-1, R = 0.0378, and wR = 0.0967. The spectral results show that the Schiff base ligand acts as a bidentate donor coordinating through the azomethine nitrogen and the carbonyl oxygen atoms. The geometrical structures of these complexes are found to be square planar. Antimicrobial studies indicate that these complexes exhibit better activity than the ligand. The anticancer activities of the complexes have also been studied towards human cervical cancer cell line (HeLa), Colon Cancer Cells (HCT116) and Epidermoid Carcinoma Cells (A431) and it was found that the [Pt(L3)Cl2] complex is more active.

  13. Metal complexes of Schiff bases derived from dicinnamoylmethane and aliphatic diamines

    Microsoft Academic Search

    K. Krishnankutty; P. Sayudevi; Basheer Ummathur

    2008-01-01

    Two new Schiff bases containing olefinic linkages have been synthe- sized by condensing aliphatic diamines with dicinnamoylmethane under speci- fied conditions. The existence of these compounds predominantly in the intra- molecularly hydrogen bonded keto-enamine form was well demonstrated by their IR, 1H-NMR and mass spectral data. Dibasic tetradentate N2O2 coordi- nation of the compounds in their (ML) complexes (M =

  14. Spectroscopic characterization of metal complexes of novel Schiff base. Synthesis, thermal and biological activity studies

    Microsoft Academic Search

    M. M. Omar; Gehad G. Mohamed; Amr A. Ibrahim

    2009-01-01

    Novel Schiff base (HL) ligand is prepared via condensation of 4-aminoantipyrine and 2-aminobenzoic acid. The ligand is characterized based on elemental analysis, mass, IR and 1H NMR spectra. Metal complexes are reported and characterized based on elemental analyses, IR, 1H NMR, solid reflectance, magnetic moment, molar conductance and thermal analyses (TGA, DrTGA and DTA). The molar conductance data reveal that

  15. Some Metal Complexes of Schiff Base Ligands Derived from Ninhydrin and Some Amino Acids

    Microsoft Academic Search

    Aly M. A. Hassaan

    1997-01-01

    The Fe(III), Cr(III) and Al(III) complexes of Schiff base ligands derived from ninhydrin with some amino acids (glycine, ?-alanine, serine) have been prepared and characterized by means of elemental analyses, IR, electronic spectra as well as conductivity and magnetic measurements. Modes of bonding and geometrical structures for these chelates are proposed.Referee I: M. S. ChinnReferee II: J. W. Fitch III

  16. Oxidation of benzoin catalyzed by oxovanadium(IV) schiff base complexes

    PubMed Central

    2013-01-01

    Background The oxidative transformation of benzoin to benzil has been accomplished by the use of a wide variety of reagents or catalysts and different reaction procedures. The conventional oxidizing agents yielded mainly benzaldehyde or/and benzoic acid and only a trace amount of benzil. The limits of practical utilization of these reagents involves the use of stoichiometric amounts of corrosive acids or toxic metallic reagents, which in turn produce undesirable waste materials and required high reaction temperatures. In recent years, vanadium complexes have attracted much attention for their potential utility as catalysts for various types of reactions. Results Active and selective catalytic systems of new unsymmetrical oxovanadium(IV) Schiff base complexes for the oxidation of benzoin is reported. The Schiff base ligands are derived between 2-aminoethanol and 2-hydroxy-1-naphthaldehyde (H2L1) or 3-ethoxy salicylaldehyde (H2L3); and 2-aminophenol and 3-ethoxysalicylaldehyde (H2L2) or 2-hydroxy-1-naphthaldehyde (H2L4). The unsymmetrical Schiff bases behave as tridentate dibasic ONO donor ligands. Reaction of these Schiff base ligands with oxovanadyl sulphate afforded the mononuclear oxovanadium(IV) complexes (VIVOLx.H2O), which are characterized by various physico-chemical techniques. The catalytic oxidation activities of these complexes for benzoin were evaluated using H2O2 as an oxidant. The best reaction conditions are obtained by considering the effect of solvent, reaction time and temperature. Under the optimized reaction conditions, VOL4 catalyst showed high conversion (>99%) with excellent selectivity to benzil (~100%) in a shorter reaction time compared to the other catalysts considered. Conclusion Four tridentate ONO type Schiff base ligands were synthesized. Complexation of these ligands with vanadyl(IV) sulphate leads to the formation of new oxovanadium(IV) complexes of type VIVOL.H2O. Elemental analyses and spectral data of the free ligands and their oxovanadium(IV) complexes were found to be in good agreement with their structures, indicating high purity of all the compounds. Oxovanadium complexes were screened for the oxidation of benzoin to benzil using H2O2 as oxidant. The effect of time, solvent and temperature were optimized to obtain maximum yield. The catalytic activity results demonstrate that these catalytic systems are both highly active and selective for the oxidation of benzoin under mild reaction conditions. PMID:23294561

  17. A new tetranuclear copper(II) complex with oximate bridges: Structure, magnetic properties and DFT study

    Microsoft Academic Search

    Sanjib Giri; Debdulal Maity; Jeffrey F. Godsell; Saibal Roy; Michael G. B. Drew; Ashutosh Ghosh; Gurucharan Mukhopadhyay; Shyamal K. Saha

    2011-01-01

    A new tetranuclear complex, [Cu4L4](ClO4)4·2H2O (1), has been synthesized from the self-assembly of copper(II) perchlorate and the tridentate Schiff base ligand (2E,3E)-3-(2-aminopropylimino) butan-2-one oxime (HL). Single-crystal X-ray diffraction studies reveal that complex 1 consists of a Cu4(NO)4 core where the four copper(II) centers having square pyramidal environment are arranged in a distorted tetrahedral geometry. They are linked together by a

  18. Synthesis, Dioxygen Affinities and Biomimetic Catalytic Oxidation Performance of Crown Ether-tethered Schiff Base Transition-Metal Complexes

    Microsoft Academic Search

    Wei Zeng; Zhihua Mao; Xingyao Wei; Jianzhang Li; Zhou Hong; Shengying Qin

    2002-01-01

    Mono-Schiff bases containing crown ether ring (HL1, HL2, HL3 and HL4) and their transition-metal complexes were synthesized and characterized by 1H NMR, IR, MS spectra and elemental analysis. The crystal structures of HL1, HL3 and CoL21 were determined from X-ray diffraction data. The oxygenation constants (Ko2) of Schiff-base Co (II) complexes were measured over a range of ?5°C to 25°C,

  19. Synthesis, Spectroscopic and Polarographic Studies of Dibutyltin(IV) Complexes of Schiff Bases Derived from 2Aminophenol

    Microsoft Academic Search

    Mala Nath; Nidhee Chaudhary

    1998-01-01

    A series of dibutyltin(IV) complexes of Schiff bases derived from 2-minophenol and benzaldehyde (HL), anisaldehyde (HL), 2-furfural (HL), acetophenone (HL), benzylmethyl ketone (HL), benzil (HL), salicylaldehyde (H2L), 2-hydroxy-l-naphthaldehyde (H2L) and 2-hydroxy-acetophenone (H2L) have been synthesized by the reaction of dibutyltin(IV) oxide with the preformed Schiff bases in 1:l or 1:2 molar ratios in benzene with azeotropical removal of water. The

  20. Studies on Some Bivalent Metal Complexes of Schiff Bases

    Microsoft Academic Search

    B. Singh; A. K. Srivastav

    1994-01-01

    2-Acetylfuran-2-furoylhydrazone (Haffh), 2-acetylthiophene-2-furoylhydrazone (Hatfh), o-hydroxyacetophenone-2-furoylhydrazone (H2hafh) and 2,6-diacetyl pyridine bis(2-furoylhydrazone) (H2dapfh) react with zinc(II), cadmium(II) and mercury(II) chlorides and form the complexes of the types ML2Cl2 [M = Cd(II) and Hg(II), L = Haffh and Hatfh; M = Zn(II), Cd(II) and Hg(II), L = H2hafh], [MLCl]Cl [M = Cd(II) and Hg(II) and L = H2dapfh] and Zn(Hhafh)2. The complexes M(H2acacfh)Cl2

  1. Schiff base ligands and their transition metal complexes in the mixtures of ionic liquid + organic solvent: a thermodynamic study.

    PubMed

    Shekaari, Hemayat; Kazempour, Amir; Khoshalhan, Maryam

    2015-01-21

    Schiff bases and their metal complexes in the mixtures of ionic liquid (IL) + organic solvent have shown great potential in attractive oxidation catalytic processes. The efficiency of such a process is strongly dependent on the various molecular interactions occurring between components. Thermodynamic properties of these systems can provide valuable information about structural interactions. Therefore, in this work, the interactions of the IL 1-hexyl-3-methylimidazolium chloride ([HMIm]Cl) with Schiff bases in organic solvents were studied through the measurements of density, viscosity, and electrical conductivity. The effect of solvent on the interactions was examined by the solutions of IL + BPIC Schiff base + solvent (C2H6O-C3H8O-C4H10O). Moreover, the influence of Schiff base ligand and Schiff base complex structures was probed by the solutions of IL + DMA + ligand (salcn/salpr/salen) and IL + DMA + complex (VO(3-OMe-salen)/VO(salophen)/VO(salen)), respectively. Using the experimental data, some important thermodynamic properties, such as standard partial molar volume (V(0)(?,IL)), experimental slope (Sv), viscosity B-coefficient, solvation number (B/V(0)(?,IL) and limiting molar conductivity (?0) were calculated and discussed in terms of solute-solvent (IL-DMF/alcohol) and solute-cosolute (IL-Schiff base) interactions. PMID:25482659

  2. Electrochemistry of oxo-technetium(V) complexes containing Schiff base and 8-quinolinol ligands

    SciTech Connect

    Refosco, F.; Mazzi, U.; Deutsch, E.; Kirchhoff, J.R.; Heineman, W.R.; Seeber, R.

    1988-11-16

    The electrochemistry of six-coordinate, monooxo technetium(V) complexes containing Schiff base ligands has been studied in acetonitrile and N,N'-dimethylformamide solutions. The complexes have the general formula TcOCl(L/sub B/)/sub 2/ or TcO(L/sub T/)(L/sub B/), where L/sub B/ represents a bidentate-N,O Schiff base ligand or a bidentate-N,O 8-quinolinol ligand and L/sub T/ represents a tridentate-O,N,O Schiff base ligand. Cyclic voltammetry at a platinum-disk electrode, controlled-potential coulometry, and thin-layer spectroelectrochemistry were used to probe both the oxidation and the reduction of these complexes. The results of these studies, and previously reported results on the analogous Re(V) complexes, can be understood within a single general reaction scheme. The salient features of this scheme are (i) one-electron reduction of Tc(V) to Tc(IV), (ii) subsequent loss of a ligand situated cis to the Tc/identical to/O linkage, and (iii) subsequent isomerization of this unstable Tc(IV) product to more stable complex in which the site trans to the Tc/identical to/O linkage is vacant. The Tc(IV) complexes can also be reduced to analogous Tc(III) species, which appear to undergo the same ligand loss and isomerization reactions. The technetium complexes are 400-500 mV easier to reduce than are their rhenium analogues. The 8-quinolinol ligands, and especially the 5-nitro derivative, both thermodynamically and kinetically stabilize the Tc(IV) and Tc(III) oxidation states. These electrogenerated species are unusual in that they constitute the bulk of the known examples of monomeric Tc(IV) and Tc(III) complexes containing only N- and O-donating ligands. 34 refs., 9 figs., 1 tab.

  3. Synthesis and characterization of copper complexes of Schiff base derived from isatin and salicylic hydrazide

    SciTech Connect

    Lekshmy, R. K., E-mail: lekshmyulloor@gmail.com, E-mail: tharapradeepkumar@yahoo.com; Thara, G. S., E-mail: lekshmyulloor@gmail.com, E-mail: tharapradeepkumar@yahoo.com [Department of Chemistry, University College, Thiruvananthapuram- 695 034, Kerala (India)

    2014-10-15

    A series of novel metal complexes of Schiff base have been prepared by the interaction of Cu(II) with isatin salicylic hydrazide. All the new compounds were characterized by elemental analysis, conductance measurement, magnetic moment determination, IR, UV, NMR, Mass and EPR spectral studies, thermal studies and microbial activities. The results indicate that the ligand acts as a tridentate chelating ligand coordinating through nitrogen and oxygen atoms. The ligand and complexes show inactive against Escherichia coli and active against Staphylococcus aureus and B.substilis. By analyzing the results of spectral, thermal and elemental analysis square planar geometry is proposed for all the complexes.

  4. Synthesis and characterization of copper complexes of Schiff base derived from isatin and salicylic hydrazide

    NASA Astrophysics Data System (ADS)

    Lekshmy, R. K.; Thara, G. S.

    2014-10-01

    A series of novel metal complexes of Schiff base have been prepared by the interaction of Cu(II) with isatin salicylic hydrazide. All the new compounds were characterized by elemental analysis, conductance measurement, magnetic moment determination, IR, UV, NMR, Mass and EPR spectral studies, thermal studies and microbial activities. The results indicate that the ligand acts as a tridentate chelating ligand coordinating through nitrogen and oxygen atoms. The ligand and complexes show inactive against Escherichia coli and active against Staphylococcus aureus and B.substilis. By analyzing the results of spectral, thermal and elemental analysis square planar geometry is proposed for all the complexes.

  5. Antimicrobial activity studies of the binuclear metal complexes derived from tridentate Schiff base ligands

    Microsoft Academic Search

    Mehmet Tümer; Hüseyin Köksal; M. Kasim Sener; Selahattin Serin

    1999-01-01

    Three novel tridentate Schiff base ligands derived from?the 3-hydroxysalicylaldehyde (H2L1), 4-hydroxysalicylaldehyde (H2L2) and 5-bromosalicylaldehyde (H2L3) with a new amine N-(pyridyl)-2-hydroxy-3-methoxy-5-aminobenzylamine (2) have been prepared. The ligands and their metal complexes have been characterized by elemental analyses, conductivity and magnetic susceptibility measurements, i.r., electronic absorption and 1H and 13C n.m.r. spectroscopy. All complexes are binuclear and, in some, the H2O molecules

  6. SYNTHESIS AND CHARACTERIZATION OF SOME BIVALENT METAL COMPLEXES OF SCHIFF BASES DERIVED FROM as-TRIAZINE

    Microsoft Academic Search

    Gurmit Singh; Ph. Ashutosh Singh; Ashok K. Sen; Kiran Singha; Surendra N. Dubeya; Ram N. Handa; Junghoon Choi

    2002-01-01

    New complexes of Co(II), Ni(II), Cu(II) and Zn(II) with the new Schiff bases derived from the condensation of 4-amino-3-mercapto-6-methyl-5-oxo-1,2,4-as-triazine (HAMMOT) with anisaldehyde (HAnMMOT), o-vanillin (H2MMOVT), indole-3-carboxyaldehyde (HIMMOT) and acetophenone (HAcMMOT), respectively, have been synthesized. The complexes were characterized by elemental analyses, magnetic susceptibility measurements, infrared and electronic spectral data. The ligands have been characterized on the basis of IR and

  7. Metal complexes of Schiff base derived from sulphametrole and o-vanilin

    Microsoft Academic Search

    Gehad G. Mohamed; Carmen M. Sharaby

    2007-01-01

    Metal complexes of Schiff base derived from condensation of o-vanilin (3-methoxysalicylaldehyde) and sulfametrole [N1-(4-methoxy-1,2,5-thiadiazole-3-yl)sulfanilamide] (H2L) are reported and characterized based on elemental analyses, IR, 1H NMR, solid reflectance, magnetic moment, molar conductance, mass spectra, UV–vis and thermal analysis (TGA). From the elemental analyses data, the complexes were proposed to have the general formulae [M2X3(HL)(H2O)5]·yH2O (where M=Mn(II), Co(II), Ni(II), Cu(II), Zn(II)

  8. Synthesis, spectral characterization, in vitro antibacterial, antifungal and cytotoxic activities of Co(II), Ni(II) and Cu(II) complexes with 1,2,4-triazole Schiff bases

    Microsoft Academic Search

    Gangadhar B. Bagihalli; Prakash Gouda Avaji; Sangamesh A. Patil; Prema S. Badami

    2008-01-01

    A series of metal complexes of cobalt(II), nickel(II) and copper(II) have been synthesized with newly synthesized biologically active 1,2,4-triazole Schiff bases derived from the condensation of 3-substituted-4-amino-5-mercapto-1,2,4-triazole and 8-formyl-7-hydroxy-4-methylcoumarin, which have been characterized by elemental analyses, spectroscopic measurements (IR, UV–vis, fluorescence, ESR), magnetic measurements and thermal studies. Electrochemical study of the complexes is also reported. All the complexes are soluble

  9. Synthesis and characterization of chromium(III) Schiff base complexes: antimicrobial activity and its electrocatalytic sensing ability of catechol.

    PubMed

    Kumar, S Praveen; Suresh, R; Giribabu, K; Manigandan, R; Munusamy, S; Muthamizh, S; Narayanan, V

    2015-03-15

    A series of acyclic Schiff base chromium(III) complexes were synthesized with the aid of microwave irradiation method. The complexes were characterized on the basis of elemental analysis, spectral analysis such as UV-Visible, Fourier transform infrared (FT-IR), nuclear magnetic resonance (NMR), electron paramagnetic resonance (EPR) spectroscopies and electrospray ionization (ESI) mass spectrometry. Electrochemical analysis of the complexes indicates the presence of chromium ion in +3 oxidation state. Cr (III) ion is stabilized by the tetradentate Schiff base ligand through its nitrogen and phenolic oxygen. From the spectral studies it is understood that the synthesized chromium(III) complexes exhibits octahedral geometry. Antimicrobial activity of chromium complexes was investigated towards the Gram positive and Gram negative bacteria. In the present work, an attempt was made to fabricate a new kind of modified electrode based on chromium Schiff base complexes for the detection of catechol at nanomolar level. PMID:25576940

  10. Synthesis and characterization of chromium(III) Schiff base complexes: Antimicrobial activity and its electrocatalytic sensing ability of catechol

    NASA Astrophysics Data System (ADS)

    Praveen Kumar, S.; Suresh, R.; Giribabu, K.; Manigandan, R.; Munusamy, S.; Muthamizh, S.; Narayanan, V.

    2015-03-01

    A series of acyclic Schiff base chromium(III) complexes were synthesized with the aid of microwave irradiation method. The complexes were characterized on the basis of elemental analysis, spectral analysis such as UV-Visible, Fourier transform infrared (FT-IR), nuclear magnetic resonance (NMR), electron paramagnetic resonance (EPR) spectroscopies and electrospray ionization (ESI) mass spectrometry. Electrochemical analysis of the complexes indicates the presence of chromium ion in +3 oxidation state. Cr (III) ion is stabilized by the tetradentate Schiff base ligand through its nitrogen and phenolic oxygen. From the spectral studies it is understood that the synthesized chromium(III) complexes exhibits octahedral geometry. Antimicrobial activity of chromium complexes was investigated towards the Gram positive and Gram negative bacteria. In the present work, an attempt was made to fabricate a new kind of modified electrode based on chromium Schiff base complexes for the detection of catechol at nanomolar level.

  11. Investigation of the oxygen affinity of manganese(II), cobalt(II) and nickel(II) complexes with some tetradentate Schiff bases

    Microsoft Academic Search

    Adel A. A. Emara; Ali M. Ali; Ahmed F. El-Asmy; El-Sayed M. Ragab

    Oxygen absorption–desorption processes for square planar Mn(II), Co(II) and Mn(II) complexes of tetradentate Schiff base ligands in DMF and chloroform solvents were investigated. The tetradentate Schiff base ligands were obtained by condensation reaction of ethylenediamine with salcyldehyde, o-hydroxyacetophenone or acetylacetone in the molar ratio 1:2. The square planar complexes were prepared by the reaction of the Schiff base ligands with

  12. Crystal structures, spectroscopic and nonlinear optical properties of metal complexes of Schiff-base ligands containing nitrogen and sulfur donors

    Microsoft Academic Search

    Yu-Peng Tian; Chun-Ying Duan; Xiao-Zeng You; Thomas C. W. Mak; Qing Luo; Jian-Ying Zhou

    1997-01-01

    ML2 type CuII chelates with the Schiff base ligands R-C6H4CHNNHC(S)SCH2Ph (R=NMe2 or -OMe) have been prepared and characterized.\\u000a Spectroscopic data suggest that the Schiff bases act as singly charged anionic bidentate ligands, forming stable neutral metal\\u000a complexes. Magnetic and e.s.r. data support a square-planar coordination geometry for both complexes. Single crystal X-ray\\u000a diffraction analysis of the complexes has established that

  13. Coordination properties of hydralazine Schiff base. Synthesis and equilibrium studies of some metal ion complexes

    NASA Astrophysics Data System (ADS)

    Shoukry, Azza A.; Shoukry, Mohamed M.

    2008-08-01

    In the present study, a new ligand is prepared by condensation of hydralazine (1-Hydralazinophthalazine) with 2-butanon-3-oxime. The acid-base equilibria of the schiff-base and the complex formation equilibria with the metal ions as Cu(II), Ni(II), Co(II), Cd(II), Mn(II) and Zn(II) are investigated potentiometrically. The stability constants of the complexes are determined and the concentration distribution diagrams of the complexes are evaluated. The effect of metal ion properties as atomic number, ionic radius, electronegativity and ionization potential are investigated. The isolated solid complexes are characterized by conventional chemical and physical methods. The potential coordination sites are assigned using the i.r. and 1H NMR spectra. The structures of the isolated solid complexes are proposed on the basis of the spectral and magnetic studies.

  14. Preparation, spectral studies, theoretical, electrochemical and antibacterial investigation of a new Schiff base and its some metal complexes

    NASA Astrophysics Data System (ADS)

    Ilhan, S.; Baykara, H.; Seyitoglu, M. S.; Levent, A.; Özdemir, S.; Dündar, A.; Öztomsuk, A.; Cornejo, M. H.

    2014-10-01

    A new Schiff base ligand, 1,6-Bis(2-(5-bromo-2-hydroxybenzylideneamino)-4-chlorophenoxy)hexane was synthesized. Some Schiff metal complexes of the new Schiff base were prepared by the reaction of some metal salts and the Schiff base. The complexes are non-electrolytes as shown by their molar conductivities (?M). The structures of metal complexes are proposed from elemental analysis, FT-IR, UV-vis, magnetic susceptibility measurements, molar conductivity measurements, mass spectra and thermal gravimetric analysis. In addition theoretical 1H NMR, HOMO-LUMO studies of the ligand; antimicrobial and cyclic voltammetric studies of the compounds were also carried out. In this study antioxidant and antibacterial activities of the compounds were examined via in vitro methods.

  15. Spectral and thermal studies of some chromium and molybdenum complexes with ONO donor Schiff bases

    NASA Astrophysics Data System (ADS)

    Soliman, Ahmed A.; Ali, Saadia A.; Orabi, Adel

    2006-11-01

    Reactions of M(CO) 6, where M = Cr and Mo with Schiff bases prepared by the condensation of ethanolamine with either acetylacetone or benzoylacetone were investigated. The reactions of Cr(CO) 6 in benzene resulted in the formation of the tricarbonyl drivatives [Cr(CO) 3(HL)], HL = acaceaH or baceaH. The HL proved to act as a tridentate ligand. The corresponding reactions with Mo(CO) 6 in dioxane gave the oxo complexes [Mo 2O 6(HL) 2] with HL was a bidentate. All prepared complexes were investigated using elemental analysis, IR, mass spectrometry, UV-vis absorption spectra and magnetic measurement. Thermal behaviors of the complexes were studied using by thermogravimetry (TG). Schemes for the thermal decomposition were proposed along with their mass fragmentation patterns.

  16. Derivatives of phosphate Schiff base transition metal complexes: synthesis, studies and biological activity

    NASA Astrophysics Data System (ADS)

    El-Wahab, Z. H. Abd; El-Sarrag, M. R.

    2004-01-01

    We report the synthesis and structural characterization of series of tetra- and hexacoordinate metal chelate complexes of phosphate Schiff base ligands having the general composition LMX n·H 2O and L 2MX n (L=phosphate Schiff base ligand; M=Ag +, Mn 2+, Cu 2+, Zn 2+, Cd 2+, Hg 2+, or Fe 3+ and X=NO 3-, Br - or Cl -). The structure of the prepared compounds was investigated using elemental analysis, IR, 1H and 31P NMR, UV-vis, mass spectra, solid reflectance, magnetic susceptibility and conductance measurements as well as conductometric titration. In all the complexes studied, the ligands act as a chelate ligand with coordination involving the phosphate?O-atom and the azomethine?N-atom. IR, solid reflectance spectra and magnetic moment measurement are used to infer the structure and to illustrate the coordination capacity of ligand. IR spectra show the presence of coordinated nitrate and water molecule, the magnetic moments of all complexes show normal magnetic behavior and the electronic spectra of the metal complexes indicate a tetra- and octahedral structure for Mn 2+, octahedral structure of Fe 3+ and both square-planar and distorted octahedral structure for Cu 2+ complexes. Antimicrobial activity of the ligands and their complexes were tested using the disc diffusion method and the chosen strains include Staphylococcus aureus, Pseudomonas aereuguinosa, Klebsiella penumoniae, Escherichia coli, Microsporum canis, Trichophyton mentagrophyte and Trichophyton rubrum. Some known antibiotics are included for the sake of comparison and the chosen antibiotic are Amikacin, Doxycllin, Augmantin, Sulperazon, Unasyn, Septrin, Cefobid, Ampicillin, Nitrofurantion, Traivid and Erythromycin.

  17. Binuclear Transition Metal Complexes of Schiff Base Macrocycles Containing the Furanyl Moiety

    Microsoft Academic Search

    Mohammad Shakir; Saji P. Varkey; Devendra Kumar

    1994-01-01

    Binucleating macrocycles L comprised of two molecules of 2,5-diformylfuran and two molecules of 1,3-diaminopropane have been synthesized as cobalt(II), nickel(II) and copper(II) complexes by template reactions. On the basis of various spectroscopic studies the 20-membered macrocyclic complexes can be described as having six-coordinate octahedral structures where L is bonding through the nitrogens of 1,3-diaminopropane and the oxygens of the furanyl

  18. SYNTHESIS AND CHARACTERIZATION OF NEW RUTHENIUM(III) COMPLEXES CONTAINING TETRADENTATE SCHIFF BASES

    Microsoft Academic Search

    T. Daniel Thangadurai; K. Natarajan

    2001-01-01

    Several new hexa-coordinated ruthenium(III) complexes of the type [RuX(EPh3)(LL?)] (X=Cl, Br; E=P, As; LL? = anthacac, anthdibm, 2-amtpacac or 2-amtpdibm) have been synthesised by reacting [RuCl3(PPh3)3], [RuCl3(AsPh3)3], [RuBr3(AsPh3)3] or [RuBr3(PPh3)2(MeOH)] with tetradentate Schiff bases such as bis(anthranilic acid)acetylacetimine (H2-anthacac), bis(anthranilic acid)dibenzoylmethimine (H2-anthdibm), bis(2-aminothiophenol)acetylacetimine (H2-2-amptacac) or bis(2-aminothiophenol)dibenzoylmethimine (H2-2-amtpdibm). All of the complexes have been characterised by elemental analyses, IR, electronic spectra,

  19. A Study of Complexation-ability of Neutral Schiff Bases to Some Metal Cations

    PubMed Central

    Topal, Giray; Tümerdem, Recep; Basaran, Ismet; Gümü?, Arzu; Cakir, Umit

    2007-01-01

    The constants of the extraction equilibrium and the distribution for dichloromethane as an organic solvent having low dielectric constant of metal cations with chiral Schiff bases, benzaldehydene-(S)-2-amino-3-phenylpropanol (I), ohydroxybenzaldehydene-( S)-2-amino-3-phenyl-propanol (II), benzaldehydene-(S)-2- amino-3-methylbutanol (III) with anionic dyes [4-(2-pyridylazo)-resorcinol mono sodium monohydrate (NaPar), sodium picrat (NaPic) and potassium picrat (KPic)] and some heavy metal chlorides were determined at 25 ºC. All the ligands have given strongest complexation for NaPar. In contrast, similar behaviour for both alkali metal picrates is not apparent in the complexation of corresponding ligands.

  20. Synthesis, characterization and the interaction of some new water-soluble metal Schiff base complexes with human serum albumin

    NASA Astrophysics Data System (ADS)

    Asadi, Mozaffar; Asadi, Zahra; Sadi, Somaye Barzegar; Zarei, Leila; Baigi, Fatemeh Moosavi; Amirghofran, Zahra

    2014-03-01

    Some new water-soluble Schiff base complexes of Na2[M(L)(H2O)n]; (M = Zn, Cu, Ni, Mn) with a new water-soluble Schiff base ligand where L denotes an asymmetric N2O2 Schiff base ligands; N,N";-bis(5-sulfosalicyliden)-3,4-diaminobenzophenone (5-SO3-3,4-salbenz) were synthesized and characterized. The formation constants of the water soluble Schiff base complexes were calculated by Ketelaar's equation. The theoretical molecular structure for the complexes was computed by using the HF method and the 6-311G basis set. The mechanism of binding of Na2[M(L)(H2O)n] with human serum albumin (HSA) was studied by fluorescence spectroscopic technique. The results of fluorescence titration showed that the intrinsic fluorescence of HSA was quenched by the complexes; which was rationalized in terms of the dynamic quenching mechanism. The values of Stern-Volmer constants, quenching rate constants, binding constants, binding sites and average aggregation number of HSA have been determined. The thermodynamic parameters, were calculated by van't Hoff equation, indicate that the binding is entropy driven and enthalpically disfavored. Based on the Förster theory of non-radiation energy transfer, the efficiency of energy transfer and the distance between the donor (Trp residues) and the acceptor (complex) were obtained. Finally, the growth inhibitory effects of the complexes toward the K562 cancer cell line were measured.

  1. Synthesis, characterization and the interaction of some new water-soluble metal Schiff base complexes with human serum albumin.

    PubMed

    Asadi, Mozaffar; Asadi, Zahra; Sadi, Somaye Barzegar; Zarei, Leila; Baigi, Fatemeh Moosavi; Amirghofran, Zahra

    2014-03-25

    Some new water-soluble Schiff base complexes of Na2[M(L)(H2O)n]; (M=Zn, Cu, Ni, Mn) with a new water-soluble Schiff base ligand where L denotes an asymmetric N2O2 Schiff base ligands; N,N'-bis(5-sulfosalicyliden)-3,4-diaminobenzophenone (5-SO3-3,4-salbenz) were synthesized and characterized. The formation constants of the water soluble Schiff base complexes were calculated by Ketelaar's equation. The theoretical molecular structure for the complexes was computed by using the HF method and the 6-311G basis set. The mechanism of binding of Na2[M(L)(H2O)n] with human serum albumin (HSA) was studied by fluorescence spectroscopic technique. The results of fluorescence titration showed that the intrinsic fluorescence of HSA was quenched by the complexes; which was rationalized in terms of the dynamic quenching mechanism. The values of Stern-Volmer constants, quenching rate constants, binding constants, binding sites and average aggregation number of HSA have been determined. The thermodynamic parameters, were calculated by van't Hoff equation, indicate that the binding is entropy driven and enthalpically disfavored. Based on the Förster theory of non-radiation energy transfer, the efficiency of energy transfer and the distance between the donor (Trp residues) and the acceptor (complex) were obtained. Finally, the growth inhibitory effects of the complexes toward the K562 cancer cell line were measured. PMID:24299984

  2. Synthesis, spectroscopic, coordination and biological activities of some organometallic complexes derived from thio-Schiff base ligands

    NASA Astrophysics Data System (ADS)

    Abou-Hussein, Azza A.; Linert, Wolfgang

    2014-01-01

    Two series of mono- and binuclear complexes cyclic or acyclic thio-ferocine Schiff base ligands, derived from the condensation of 2-aminobenzenthiol (L) with monoacetyl ferrocene in the molar ratio 1:1 or in the molar ratio 1:2 for diacetyl ferocine have been prepared. The condensation reactions yield the corresponding Schiff Base ligands, HLa-Maf and H2Lb-Daf. The chelation of the ligands to metal ions occurs through the sulfur of the thiol group as well as the nitrogen atoms of the azomethine group of the ligands. HLa-Maf acts as monobasic bidentate or dibasic tetradentate, while H2Lb-Daf behaves as twice negatively cargend tetradentate ligand. The structures of these ligands were elucidated by elemental analysis, infrared, ultraviolet-visible spectra, as well as 1H NMR spectra. Reactions of the Schiff bases ligands with ruthenium(III), oxovanadium(IV) and dioxouranium(VI) afforded the corresponding transition metal complexes. The properties of the newly prepared complexes were analyse by elemental analyses, infrared, electronic spectra, 1H NMR as well as the magnetic susceptibility and conductivity measurement. The metal complexes exhibits different geometrical arrangements such as octahedral and square pyramidal coordination. Schiff base ligands and their metal complexes were tested against two pathogenic bacteria as Gram-positive and Gram-negative bacteria as well as one kind of fungi to study their biological activity. All the complexes exhibit antibacterial and antifungal activities against these organisms.

  3. Synthesis, spectroscopic, coordination and biological activities of some organometallic complexes derived from thio-Schiff base ligands

    PubMed Central

    Abou-Hussein, Azza A.; Linert, Wolfgang

    2014-01-01

    Two series of mono- and binuclear complexes cyclic or acyclic thio-ferocine Schiff base ligands, derived from the condensation of 2-aminobenzenthiol (L) with monoacetyl ferrocene in the molar ratio 1:1 or in the molar ratio 1:2 for diacetyl ferocine have been prepared. The condensation reactions yield the corresponding Schiff Base ligands, HLa-Maf and H2Lb-Daf. The chelation of the ligands to metal ions occurs through the sulfur of the thiol group as well as the nitrogen atoms of the azomethine group of the ligands. HLa-Maf acts as monobasic bidentate or dibasic tetradentate, while H2Lb-Daf behaves as twice negatively cargend tetradentate ligand. The structures of these ligands were elucidated by elemental analysis, infrared, ultraviolet–visible spectra, as well as 1H NMR spectra. Reactions of the Schiff bases ligands with ruthenium(III), oxovanadium(IV) and dioxouranium(VI) afforded the corresponding transition metal complexes. The properties of the newly prepared complexes were analyse by elemental analyses, infrared, electronic spectra, 1H NMR as well as the magnetic susceptibility and conductivity measurement. The metal complexes exhibits different geometrical arrangements such as octahedral and square pyramidal coordination. Schiff base ligands and their metal complexes were tested against two pathogenic bacteria as Gram-positive and Gram-negative bacteria as well as one kind of fungi to study their biological activity. All the complexes exhibit antibacterial and antifungal activities against these organisms. PMID:24070648

  4. Spacer-dependent structural and physicochemical diversity in copper(II) complexes with salicyloyl hydrazones: a monomer and soluble polymers.

    PubMed

    Matoga, Dariusz; Szklarzewicz, Janusz; Grybo?, Ryszard; Kurpiewska, Katarzyna; Nitek, Wojciech

    2011-04-18

    Complexation of copper(II) with a series of heterodonor chelating Schiff bases (LL) of salicylic acid hydrazide and aliphatic or cycloaliphatic ketones affords soluble one-dimensional (1D) metallopolymers containing Schiff bases as bridging ligands. Single-crystal X-ray diffraction results reveal nanometer-sized metallopolymeric wires [Cu(?-LL)(2)](n) with off-axis linkers and a zigzag geometry. Octahedrally coordinated copper centers, exhibiting a Jahn-Teller distortion, are doubly bridged by two Schiff-base molecules in the ?(2)-?(1),?(2) coordination mode. The use of dibutylketone with long alkyl chains as a component for Schiff base formation leads to a distorted square planar monomeric copper(II) complex [Cu(LL)(2)], as evidenced by its X-ray crystal structure. The compounds are characterized by elemental analyses and IR and UV-vis spectroscopy, as well as magnetic susceptibility and cyclic voltammetry measurements. Electrochemical studies on the complexes reveal an existence of polymeric and monomeric forms in solution and the dependence of Cu(II)/Cu(I) reduction potentials on alkyl groups of salicyloyl hydrazone ligands. Polymeric complexes form conducting films on Pt electrodes upon multicycle potential sweeps. PMID:21428390

  5. Synthesis, characterization, and antipathogenic studies of some transition metal complexes with N,O-chelating Schiff's base ligand incorporating azo and sulfonamide Moieties

    NASA Astrophysics Data System (ADS)

    Alaghaz, Abdel-Nasser M. A.; Bayoumi, Hoda A.; Ammar, Yousry A.; Aldhlmani, Sharah A.

    2013-03-01

    Chromium(III), Manganese(II), Cobalt(II), nickel(II), copper(II) and cadmium(II) complexes of 4-[4-hydroxy-3-(phenyliminomethyl)-phenylazo]benzenesulfonamide, were prepared and characterized on the basis of elemental analyses, spectral, magnetic, molar conductance and thermal analysis. Square planar, tetrahedral and octahedral geometries have been assigned to the prepared complexes. Dimeric complexes are obtained with 2:2 molar ratio except chromium(III) complex is monomeric which is obtained with 1:1 molar ratios. The IR spectra of the prepared complexes were suggested that the Schiff base ligand(HL) behaves as a bi-dentate ligand through the azomethine nitrogen atom and phenolic oxygen atom. The crystal field splitting, Racah repulsion and nepheloauxetic parameters and determined from the electronic spectra of the complexes. Thermal studies suggest a mechanism for degradation of HL and its metal complexes as function of temperature supporting the chelation modes. Also, the activation thermodynamic parameters, such as ?E*, ?H*, ?S* and ?G* for the different thermal decomposition steps of HL and its metal complexes were calculated. The pathogenic activities of the synthesized compounds were tested in vitro against the sensitive organisms Staphylococcus aureus (RCMB010027), Staphylococcus epidermidis (RCMB010024) as Gram positive bacteria, Klebsiella pneumonia (RCMB 010093), Shigella flexneri (RCMB 0100542), as Gram negative bacteria and Aspergillus fumigates (RCMB 02564), Aspergillus clavatus (RCMB 02593) and Candida albicans (RCMB05035) as fungus strain, and the results are discussed.

  6. Metal Complexes of Macrocyclic Schiff-Base Ligand: Preparation, Characterisation, and Biological Activity

    PubMed Central

    Ahmed, Riyadh M.; Yousif, Enaam I.; Hasan, Hasan A.; Al-Jeboori, Mohamad J.

    2013-01-01

    A new macrocyclic multidentate Schiff-base ligand Na4L consisting of two submacrocyclic units (10,21-bis-iminomethyl-3,6,14,17-tricyclo[17.3.1.18,12]tetracosa-1(23),2,6,8,10,12(24),13,17,19,21,-decaene-23,24-disodium) and its tetranuclear metal complexes with Mn(II), Co(II), Ni(II), Cu(II), and Zn(II) are reported. Na4L was prepared via a template approach, which is based on the condensation reaction of sodium 2,4,6-triformyl phenolate with ethylenediamine in mole ratios of 2?:?3. The tetranuclear macrocyclic-based complexes were prepared from the reaction of the corresponding metal chloride with the ligand. The mode of bonding and overall geometry of the compounds were determined through physicochemical and spectroscopic methods. These studies revealed tetrahedral geometries about Mn, Co, and Zn atoms. However, square planar geometries have been suggested for NiII and CuII complexes. Biological activity of the ligand and its metal complexes against Gram positive bacterial strain Staphylococcus aureus and Gram negative bacteria Escherichia coli revealed that the metal complexes become more potentially resistive to the microbial activities as compared to the free ligand. However, these metal complexes do not exhibit any effects on the activity of Pseudomonas aeruginosa bacteria. There is therefore no inhibition zone. PMID:23935414

  7. Synthesis, molecular structure, and properties of a neutral Schiff base phenolic complex of magnesium

    SciTech Connect

    Polyakov, V.R.; Sharma, V.; Crankshaw, C.L.; Piwnica-Worms, D. [Washington University Medical School, St. Louis, MO (United States)] [Washington University Medical School, St. Louis, MO (United States)

    1998-09-07

    Multidrug resistance (MDR) in cancer mediated by the MDR1 P-glycoprotein (Pgp), a 140--180 kDa plasma membrane protein, renders chemotherapeutic treatment ineffective by pumping a variety of natural product cytotoxic agents and xenobiotic compounds out of cancer cells. Pgp has been a major target for synthesis and development of both therapeutic antagonists that block its transport function and diagnostic radiopharmaceuticals that are transported by the protein for use in functional imaging of Pgp transport activity in tumors in vivo. Most, but not all, compounds that interact with Pgp are hydrophobic and cationic at physiological pH. To further understand the Pgp targeting properties, the authors sought to directly evaluate the effect of charge of the complex on Pgp interactions. This could be done by comparing the cytotoxicity profile of a neutral complex to that of an identical, but positively charged, complex in both drug-sensitive and multidrug-resistant cancer cells. Thus, a neutral analogue of the Ga(III) and Fe(III) complexes was desired. Herein the authors describe the synthesis and structure of a novel neutral Schiff base Mg complex and evaluate its cytotoxic potency in human drug-sensitive KB-3-1 and multi-drug-resistant KB-8-5 tumor cells.

  8. Exploring DNA binding and nucleolytic activity of few 4-aminoantipyrine based amino acid Schiff base complexes: A comparative approach

    NASA Astrophysics Data System (ADS)

    Raman, N.; Sakthivel, A.; Pravin, N.

    A series of novel Co(II), Cu(II), Ni(II) and Zn(II) complexes were synthesized from Schiff base(s), obtained by the condensation of 4-aminoantipyrine with furfural and amino acid (glycine(L1)/alanine(L2)/valine(L3)) and respective metal(II) chloride. Their structural features and other properties were explored from the analytical and spectral methods. The binding behaviors of the complexes to calf thymus DNA were investigated by absorption spectra, viscosity measurements and cyclic voltammetry. The intrinsic binding constants for the above synthesized complexes are found to be in the order of 102 to 105 indicating that most of the synthesized complexes are good intercalators. The binding constant values (Kb) clearly indicate that valine Schiff-base complexes have more intercalating ability than alanine and glycine Schiff-base complexes. The results indicate that the complexes bind to DNA through intercalation and act as efficient cleaving agents. The in vitro antibacterial and antifungal assay indicates that these complexes are good antimicrobial agents against various pathogens. The IC50 values of [Ni(L1)2] and [Zn(L1)2] complexes imply that these complexes have preferable ability to scavenge hydroxyl radical.

  9. Exploring DNA binding and nucleolytic activity of few 4-aminoantipyrine based amino acid Schiff base complexes: a comparative approach.

    PubMed

    Raman, N; Sakthivel, A; Pravin, N

    2014-05-01

    A series of novel Co(II), Cu(II), Ni(II) and Zn(II) complexes were synthesized from Schiff base(s), obtained by the condensation of 4-aminoantipyrine with furfural and amino acid (glycine(L1)/alanine(L2)/valine(L3)) and respective metal(II) chloride. Their structural features and other properties were explored from the analytical and spectral methods. The binding behaviors of the complexes to calf thymus DNA were investigated by absorption spectra, viscosity measurements and cyclic voltammetry. The intrinsic binding constants for the above synthesized complexes are found to be in the order of 10(2) to 10(5) indicating that most of the synthesized complexes are good intercalators. The binding constant values (Kb) clearly indicate that valine Schiff-base complexes have more intercalating ability than alanine and glycine Schiff-base complexes. The results indicate that the complexes bind to DNA through intercalation and act as efficient cleaving agents. The in vitro antibacterial and antifungal assay indicates that these complexes are good antimicrobial agents against various pathogens. The IC50 values of [Ni(L1)2] and [Zn(L1)2] complexes imply that these complexes have preferable ability to scavenge hydroxyl radical. PMID:24566120

  10. Synthesis, Spectral, and In Vitro Antibacterial Studies of Organosilicon(IV) Complexes with Schiff Bases Derived from Amino Acids

    PubMed Central

    Singh, Har Lal; Singh, Jangbhadur; Mukherjee, A.

    2013-01-01

    The present work stems from our interest in the synthesis, characterization, and antibacterial evaluation of organosilicon(IV) complexes of a class of amino-acid-based Schiff base which have been prepared by the interaction of ethoxytrimethylsilane with the Schiff bases (N OH) in 1?:?1 molar ratio. These complexes have been characterized by elemental analysis, molar conductance, and spectroscopic studies including electronic IR and NMR (1H, 13C, and 29Si) spectroscopy. The analytical and spectral data suggest trigonal bipyramidal geometry around the silicon atom in the resulting complexes. The ligands and their organosilicon complexes have also been evaluated for in vitro antimicrobial activity against bacteria (Bacillus cereus, Nocardia spp., E. aerogenes, Escherichia coli, Klebsiella spp., and Staphylococcus spp.). The complexes were found to be more potent as compared to the ligands. PMID:23983671

  11. Two new heterodinuclear Schiff base complexes: Synthesis, crystal structure and thermal studies

    NASA Astrophysics Data System (ADS)

    Yardan, Alper; Hopa, Cigdem; Yahsi, Yasemin; Karahan, Ahmet; Kara, Hulya; Kurtaran, Raif

    2015-02-01

    Two new heterodinuclear Schiff base complexes, [Hg(L)NiCl2(DMF)2] 1, and [Zn(L)NiCl2(DMF)2] 2, where H2L = N,N?-bis(salicylidene)-1,3-diaminopropane and DMF = dimethylformamide have been synthesized and characterized using elemental analysis, IR spectroscopy, thermal analysis and X-ray diffraction. Structural studies on 1 and 2 reveal the presence of a heterodinuclear [NiIIHgII] unit and [ZnIINiII] in which the central metal ions are connected to each other by two phenolate oxygen bridges. For complex 1 the Ni(II) ion adopts an elongated octahedral geometry (NiN2O4) while the Hg(II) ion assumes a distorted tetrahedral arrangement (HgO2Cl2) whereas for complex 2 the Zn(II) ion adopts an elongated octahedral geometry (ZnN2O4) while the Ni(II) ion assumes a distorted tetrahedral arrangement (NiO2Cl2). There are intermolecular Csbnd H···Clsbnd M interactions among the dinuclear complexes which are interconnected for 1 and 2. These intermolecular interactions result in the formation of a three dimensional structure for 1 and one dimensional zig-zag chains for 2.

  12. Synthesis, characterization and experimental, theoretical, electrochemical, antioxidant and antibacterial study of a new Schiff base and its complexes

    NASA Astrophysics Data System (ADS)

    Baykara, Haci; Ilhan, Salih; Levent, Abdulkadir; Salih Seyitoglu, M.; Özdemir, Sadin; Okumu?, Veysi; Öztomsuk, Abdussamet; Cornejo, Mauricio

    2014-09-01

    A new Schiff base ligand was synthesized by reaction of salicylaldehyde with 1,6-bis(4-chloro-2-aminophenoxy)hexane. Then the Schiff base complexes were synthesized by metal salts and the Schiff base. The metal to ligand ratio of metal complexes was found to be 1:1. The Cu(II) complex is proposed to be square planar and the Co(II), Ni(II), Mn(II) and Zn(II) complexes are proposed to be tetrahedral geometry. The Ti(III) and V(III) complexes are proposed to be a capped octahedron in which a seventh ligand has been added to triangular face. The complexes are non-electrolytes as shown by their molar conductivities (?M). The structure of metal complexes is proposed from elemental analysis, FT-IR, UV-vis, magnetic susceptibility measurements, molar conductivity measurements, Mass Spectra and thermal gravimetric analysis. In addition antimicrobial and antioxidant studies, cyclic voltammetry of the complexes, theoretical 1H NMR and HOMO-LUMO energy calculations of the new di-functional ligand were done.

  13. Synthesis, characterization and experimental, theoretical, electrochemical, antioxidant and antibacterial study of a new Schiff base and its complexes.

    PubMed

    Baykara, Haci; Ilhan, Salih; Levent, Abdulkadir; Salih Seyitoglu, M; Özdemir, Sadin; Okumu?, Veysi; Öztomsuk, Abdussamet; Cornejo, Mauricio

    2014-09-15

    A new Schiff base ligand was synthesized by reaction of salicylaldehyde with 1,6-bis(4-chloro-2-aminophenoxy)hexane. Then the Schiff base complexes were synthesized by metal salts and the Schiff base. The metal to ligand ratio of metal complexes was found to be 1:1. The Cu(II) complex is proposed to be square planar and the Co(II), Ni(II), Mn(II) and Zn(II) complexes are proposed to be tetrahedral geometry. The Ti(III) and V(III) complexes are proposed to be a capped octahedron in which a seventh ligand has been added to triangular face. The complexes are non-electrolytes as shown by their molar conductivities (?M). The structure of metal complexes is proposed from elemental analysis, FT-IR, UV-vis, magnetic susceptibility measurements, molar conductivity measurements, Mass Spectra and thermal gravimetric analysis. In addition antimicrobial and antioxidant studies, cyclic voltammetry of the complexes, theoretical 1H NMR and HOMO-LUMO energy calculations of the new di-functional ligand were done. PMID:24792202

  14. Synthesis, characterization and DNA interaction of copper (II) complexes with Schiff base ligands derived from 2-pyridinecarboxaldehyde and polyamines

    Microsoft Academic Search

    Xin-Bin Yang; Yu Huang; Jin-Sheng Zhang; Shu-Kai Yuan; Ren-Quan Zeng

    2010-01-01

    A series of copper (II) complexes a–d with Schiff bases ligands derived from the condensation reactions between 2-pyridinecarboxaldehyde and different polyamines (ethylenediamine, diethylenetriamine, triethylenetetramine and tetraethylenepentamine) were synthesized and characterized by elemental analysis, FT-IR spectroscopy, HRMS, molar conductance and molecular modeling studies. The interactions of the copper complexes a–d with DNA were investigated by the UV spectra, viscosity measurements and

  15. Large and negative magnetic anisotropy in pentacoordinate mononuclear Ni(ii) Schiff base complexes.

    PubMed

    Nemec, Ivan; Herchel, Radovan; Svoboda, Ingrid; Bo?a, Roman; Trávní?ek, Zden?k

    2015-05-12

    A series of pentacoordinate Ni(ii) complexes of the general formula [Ni(L5)] () with various pentadentate Schiff base ligands H2L5 (originating in a condensation of aromatic ortho-hydroxy-aldehydes and aliphatic triamines) was synthesized and characterized by X-ray structure analysis and magnetometry. The alternations of substituents on the H2L parent ligand resulted in the complexes with the geometry varying between the square-pyramid and trigonal-bipyramid. In the compounds whose chromophore geometry is closer to a trigonal-bipyramid, a large and negative uniaxial anisotropy (D = -64 cm(-1)) was identified. Moreover, the simple linear expression for the axial zero-field splitting (ZFS) parameter, D/cm(-1) = 32.7(4.8) - 151(10)?, was proposed, where ? (in degrees) stands for the Addison parameter. The results of magnetic analysis were also supported by ab initio CASSCF/NEVPT2 calculations of the ZFS splitting parameters D and E, and g tensors. Despite large and negative D-values of the reported compounds, slow relaxation of magnetization was not observed either in zero or non-zero static magnetic field, thus no single-molecule magnetic behaviour was detected. PMID:25919125

  16. Selective Anion Binding by a Cofacial Binuclear Zinc Complex of a Schiff-Base Pyrrole Macrocycle

    PubMed Central

    Devoille, Aline M. J.; Richardson, Patricia; Bill, Nathan; Sessler, Jonathan L.; Love, Jason B.

    2011-01-01

    The synthesis of the new cofacial binuclear zinc complex [Zn2(L)] of a Schiff-base pyrrole macrocycle is reported. It was discovered that the binuclear microenvironment between the two metals of [Zn2(L)] is suited for the encapsulation of anions, leading to the formation of [K(THF)6][Zn2(?-Cl)(L)].2THF and [Bun4N][Zn2(?-OH)(L)] which were characterized by X-ray crystallography. Unusually obtuse Zn-X-Zn angles (X=Cl: 150.54(9)° and OH: 157.4(3)°) illustrate the weak character of these interactions and the importance of the cleft pre-organization to stabilize the host. In the absence of added anion, aggregation of [Zn2(L)] was inferred and investigated by successive dilutions and by the addition of coordinating solvents to [Zn2(L)] solutions using NMR spectroscopy as well as isothermal microcalorimetry (ITC). On anion addition, evidence for de-aggregation of [Zn2(L)], combined with the formation of the 1:1 host-guest complex, was observed by NMR spectroscopy and ITC titrations. Furthermore, [Zn2(L)] binds to Cl? selectively in THF as deduced from the ITC analyses, while other halides induce only de-aggregation. These conclusions were reinforced by DFT calculations, which indicated that the binding energies of OH? and Cl? were significantly greater than for the other halides. PMID:21391550

  17. Synthesis and characterization of two oxovanadium (IV) Schiff base complexes derived from amino acids and pyridoxal

    NASA Astrophysics Data System (ADS)

    Yue, Huijuan; Zhang, Dong; Shi, Zhan; Feng, Shouhua

    2006-11-01

    Two N-pyridoxylideneamino acidato complexes of oxovanadium (IV), [VO(pyr-D,L-Met)(bipy)] and [VO(pyr-D,L-Thr)(bipy)]?H 2O with Schiff bases, made from amino acids (DL-methionine and DL-threonine) and pyridoxal, were prepared by an amine-diffusion reaction and characterized by single crystal X-ray diffraction. Both [VO(pyr-D,L-Met)(bipy)] and [VO(pyr-D,L-Thr)(bipy)]?H 2O crystallize in triclinic P-1 with cell parameters a=9.2605(19) Å, b=12.851(3) Å, c=19.079(4) Å, ?=92.34(3)°, ?=93.20(3)°, ?=91.03(3)°, V=2264.7(8) Å, Z=2, and a=9.4513(8) Å, b=11.9026(13) Å, c=12.7589(12) Å, ?=66.836(6)°, ?=87.171(6)°, ?=67.214(6)°, V=1207.6(2) Å, Z=2, respectively. They contain two diastereomers, donating the chiral vanadium centers as A or C, e.g., [A(pyr-D-Met)(bipy)], [C(pyr-L-Met)(bipy)] and [A(pyr-D-Thr)(bipy)]?H 2O, [C(pyr-L-Thr)(bipy)]?H 2O. The complexes were also characterized by elemental analysis, IR and EPR spectroscopy. The EPR spectra illustrate well-resolved coupling of the unpaired electron with V51 nucleus ( I=7/2).

  18. Polymer Supported Schiff Base Complexes of Iron(III), Cobalt(II) and Nickel(II) Ions and their Catalytic Activity in Oxidation of Phenol and Cyclohexene

    Microsoft Academic Search

    K. C. Gupta; A. K. Sutar

    2007-01-01

    The polymer supported transition metal complexes of N,N??bis (o?hydroxy acetophenone) hydrazine (HPHZ) Schiff base were prepared by immobilization of N,N??bis(4?amino?o?hydroxyacetophenone)hydrazine (AHPHZ) Schiff base on chloromethylated polystyrene beads of a constant degree of crosslinking and then loading iron(III), cobalt(II) and nickel(II) ions in methanol. The complexation of polymer anchored HPHZ Schiff base with iron(III), cobalt(II) and nickel(II) ions was 83.30%, 84.20%

  19. Synthesis and characterization of Schiff base octaazamacrocyclic complexes and their biological studies.

    PubMed

    Zafar, Hina; Kareem, Abdul; Sherwani, Asif; Mohammad, Owais; Ansari, Mohammad Azam; Khan, Haris M; Khan, Tahir Ali

    2015-01-01

    A condensation reaction between 1,2-diphenylethane-1,2-dione dihydrazone (DPEDDH) and dimethyl or diethyloxalate in methanol resulted in a novel Schiff base octaazamacrocyclic ligand, (L): (6,7,14,15-tetraoxa-2,3,10,11-tetraphenyl-1,4,5,8,9,12,13,16-octaazacyclohexadecane-1,3,9,11-tetraene). Subsequently metal complexes of the type [MLX2] and [CuL]X2; (M=Mn(II), Co(II), Ni(II) and Zn(II); X=Cl or NO3) were synthesized by the reaction of the free macrocyclic ligand (L) with the corresponding metal salts in 1:1 molar ratio. These complexes were characterized on the basis of analytical data, molar conductivity and magnetic susceptibility measurements, ESI-mass, IR, NMR ((1)H and (13)C), EPR and electronic spectral studies. The thermal stability of the complexes was also studied by TGA and DTA analyses. These studies show that all the complexes have octahedral arrangement around the metal ions except copper complexes which are square planar. The ligand and its complexes were screened for their antibacterial activity in vitro against Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria and were also studied for their anticancer activity against the human cancer cells lines: HeLa (Human cervical carcinoma), MCF7 (Human breast adenocarcinoma) and Hep3B (Human Hepatocellular carcinoma). The recorded IC50 values for the tested compounds show moderate to good cytotoxicity against these cancer cell lines. The copper complex, [CuL]Cl2, showed excellent antimicrobial activity against tested microorganisms which is almost equivalent to the standard drug ciprofloxacin. PMID:25490374

  20. Synthesis and characterization of VO(II), Co(II), Ni(II), Cu(II) and Zn(II) complexes of chromone based azo-linked Schiff base ligand

    NASA Astrophysics Data System (ADS)

    Anitha, C.; Sheela, C. D.; Tharmaraj, P.; Johnson Raja, S.

    2012-12-01

    Azo-Schiff-base complexes of VO(II), Co(II), Ni(II), Cu(II) and Zn(II) have been synthesized and characterized by elemental analysis, IR, UV-Vis, 1H NMR, mass spectra, molar conductance, magnetic susceptibility measurement, electron spin resonance (EPR), CV, fluorescence, NLO and SEM. The conductance data indicate the nonelectrolytic nature of the complexes, except VO(II) complex which is electrolytic in nature. On the basis of electronic spectra and magnetic susceptibility octahedral geometry has been proposed for the complexes. The EPR spectra of copper and oxovanadium complexes in DMSO at 300 and 77 K were recorded and its salient features are reported. The redox behavior of the copper(II) complex was studied using cyclic voltammetry. The in vitro antimicrobial activity against Staphylococcus aureus, Escherichia coli, Salmonella enterica typhi, Bacillus subtilis and Candida strains was studied and compared with that of free ligand by well-diffusion technique. The azo Schiff base exhibited fluorescence properties originating from intraligand (?-??) transitions and metal-mediated enhancement is observed on complexation and so the synthesized complexes can serve as potential photoactive materials as indicated from their characteristic fluorescence properties. On the basis of the optimized structures, the second-order nonlinear optical properties (NLO) are calculated by using second-harmonic generation (SHG) and also the surface morphology of the complexes was studied by SEM.

  1. Microwave assisted synthesis and characterization of unsymmetrical tetradentate Schiff base complexes of VO(IV) and MoO(V)

    NASA Astrophysics Data System (ADS)

    Thaker, B. T.; Barvalia, R. S.

    2011-12-01

    Microwave synthesis, is green chemical method, simple, sensitive, reducing solvent amount and reaction time. The attempt was made to synthesize the unsymmetrical tetradentate N 2O 2 ligands and their VO(IV) and MoO(V) unsymmetrical tetradentate Schiff base complexes by classical and microwave techniques using domestic microwave oven. The resulting unsymmetrical Schiff base ligands L 1-L 3 characterized by different spectral methods. Their complexes with oxocations of VO(IV) and MoO(V) have been synthesized and characterized by elemental analyses, conductometric measurements, infrared and electronic absorption, 1H NMR spectra, mass spectrometry, ESR spectra, magnetic susceptibility measurement and thermal study. The study suggests that the oxo metal ion is bonded to the ligand through the oxygen and imino nitrogen and the geometry around metal ion is distorted octahedral.

  2. Synthesis and antibacterial activities of metal(II) complexes with Schiff bases derived from 3,5-diiodosalicylaldehyde

    Microsoft Academic Search

    Suo-Ping Xu; Lei Shi; Peng-Cheng Lv; Rui-Qin Fang; Hai-Liang Zhu

    2009-01-01

    Two new Schiff bases (2,4-diiodo-6-[(2-morpholin-4-yl-ethylimino)-methyl]-phenol and 2,4-diiodo-6-[(3-morpholin-4-yl-propylimino)-methyl]-phenol), condensed from 3,5-diiodosalicylaldehyde with 2-morpholinoethylamine and 3-morpholinopropylamine, have been designed and synthesized. Reaction of the Schiff bases with Zn(OAc)2 · 2H2O, Cu(OAc)2 · H2O, Ni(OAc)2 · 4H2O, Co(OAc)2 · 4H2O, Cd(OAc)2 · 2H2O, Mn(OAc)2 · 4H2O, Fe(SO4)2 · 7H2O, and Hg(OAc)2 led to the formation of 16 new mononuclear complexes. The complexes were

  3. Sulfate-selective PVC membrane electrode based on a strontium Schiff's base complex.

    PubMed

    Ganjali, Mohammad Reza; Norouzi, Parviz; Gol-Mohammadi, Mahmood; Mizani, Farhang; Poursaberi, Tahereh; Salavati-Niasari, Masoud; Shamsipur, Mojtaba; Hosseini, Morteza; Javanbakht, Mehran

    2003-01-01

    A strontium Schiff's base complex (SS) can be used as a suitable ionophore to prepare a sulfate-selective PVC-based membrane electrode. The use of oleic acid (OA) and hexadecyltrimethylammonium bromide (HTAB), as additives, and nitrobenzen (NB), dibutyl phthalate (DBP) and benzyl acetate (BA) as solvent mediators, were investigated. The best performance was observed with a membrane composition PVC: NB: SS: HTAB of 30%: 62%: 5%: 3% ratio. The resulting sensor works well over a wide concentration range (1.0 x 10(-2)-1.0 x 10(-6) M) with a Nernstian slope of -29.2 mV per decade of sulfate activity over a pH range 4.0-7.0. The limit of detection of the electrode is 5 x 10(-7) M. The proposed sensor shows excellent discriminating ability toward SO4(2-) ions with regard to many anions. It has a fast response time of about 15 s. The membrane electrode was used to the determination of zinc in zinc sulfate tablets. The sensor was also used as an indicator electrode in the potentiometric titration of SO4(2-) against barium ion. PMID:12940601

  4. Interaction of a copper(II)–Schiff base complexes with calf thymus DNA and their antimicrobial activity

    Microsoft Academic Search

    D. Sabolová; M. Kožurková; T. Plichta; Z. Ondrušová; D. Hudecová; M. Šimkovi?; H. Paulíková; A. Valent

    2011-01-01

    The interaction of a copper complexes containing Schiff bases with calf thymus (CT) DNA was investigated by spectroscopic methods. UV–vis, fluorescence and CD spectroscopies were conducted to assess their binding ability with CT DNA. The binding constants K have been estimated from 0.8 to 9.1×104M?1. The percentage of hypochromism is found to be over 70% (from spectral titrations). The results

  5. PM3 semi-empirical IR spectra simulations for metal complexes of schiff bases of sulfa drugs

    Microsoft Academic Search

    C. Topacli; A Topacli

    2003-01-01

    The molecular structures and infrared spectra of Co, Ni, Cu and Zn complexes of two schiff base ligands, viz N-(o-vanillinidene)sulfanilamide (oVSaH) and N-(o-vanillinidene)sulfamerazine (oVSmrzH) are studied in detail by PM3 method. It has been shown that the proposed structures for the compounds derived from microanalytical, magnetic and various spectral data were consistent with the IR spectra simulated by PM3 method.

  6. Optical Resolution of ?-Amino Acids by Reverse Osmosis using Enantioselective Polymer Membrane Containing Chiral Metal-Schiff Base Complex

    Microsoft Academic Search

    Kripal Singh; Pravin G. Ingole; H. C. Bajaj; Amit Bhattacharya; Harshad R. Brahmbhatt

    2010-01-01

    The optical resolution of ?-amino acids, arginine and alanine was performed by reverse osmosis at 517.10 kPa and 1034.21 kPa pressures using enantioselective composite nanofiltration membrane prepared by interfacial co-polymerizing, a mixture of Zinc metal Schiff's base complex and piperazine with trimesoyl chloride in-situ on the top of polysulfone ultrafiltration membrane. The chemical composition of the enantioselective layer was determined by ATR-FTIR

  7. Spectral, magnetic, biocidal screening, DNA binding and photocleavage studies of mononuclear Cu(II) and Zn(II) metal complexes of tricoordinate heterocyclic Schiff base ligands of pyrazolone and semicarbazide/thiosemicarbazide based derivatives

    NASA Astrophysics Data System (ADS)

    Raman, N.; Selvan, A.; Manisankar, P.

    2010-07-01

    We depict the synthesis and characterization of copper(II) and zinc(II) coordination compounds of 4-(3',4'-dimethoxybenzaldehydene)2-3-dimethyl-1-phenyl-3-pyrazolin-5-semicarbazone ( 1a), 4-(3',4'-dimethoxybenzaldehydene)2-3-dimethyl-1-phenyl-3-pyrazolin-5-thiosemicarbazone ( 1b), 4-(3'-hydroxy-4'-nitrobenzaldehydene)2-3-dimeth yl-1-phenyl-3-pyrazolin-5-semicarbazone ( 1c) and 4-(3'-hydroxy-4'-nitrobenzal dehydene)2-3-dimethyl-1-phenyl-3-pyrazolin-5-thiosemicarbazone ( 1d). All the remote compounds have the general composition [ML 2] (M = Cu(II) and Zn(II)); L = Schiff base ( 1a- 1d). All the complexes were characterized by elemental analysis, molar conductivity, IR, 1H NMR, UV-vis, ESI-Mass, magnetic susceptibility measurements, cyclic voltammetric measurements, and EPR spectral studies. It has been originated that the Schiff bases with Cu(II) and Zn(II) ions form mononuclear complexes on 1:2 (metal:ligand) stoichiometry. Distorted octahedral environment is suggested for the metal complexes. The conductivity data confirm the non-electrolytic nature of the complexes. The interaction of CuL 21a- 1d complexes with CT DNA was investigated by spectroscopic, electrochemical and viscosity measurements. Results suggest that the copper complexes bind to DNA via an intercalative mode. Moreover, the complexes have been found to promote the photocleavage of plasmid DNA pBR322 under irradiation at 365 nm. The Schiff bases and their metal complexes were screened for their antifungal and antibacterial activities against different species of pathogenic fungi and bacteria and their biopotency has been discussed.

  8. A rare ferromagnetically coupled asymmetric doubly azido bridged copper(II) dimer with an N, N, O donor Schiff base

    Microsoft Academic Search

    Shyamapada Shit; Pritha Talukder; Joy Chakraborty; Guillaume Pilet; M. Salah El Fallah; Joan Ribas; Samiran Mitra

    2007-01-01

    A new end-to-end (EE) doubly azido bridged dinuclear complex [Cu2L2(?1,3-N3)2] (1) [where L=(E)-4-(2-(dimethylamino)ethylimino)-1,1,1-trifluoropentan-2-one)] has been synthesized and characterized by elemental and spectroscopic techniques. Single crystal X-ray diffraction analysis reveals that the dimeric complex possesses a center of inversion. Each copper atom in 1 is in a distorted square pyramidal geometry with a CuN4O chromophore as revealed from the ? value,

  9. Surfactant-copper(II) Schiff base complexes: synthesis, structural investigation, DNA interaction, docking studies, and cytotoxic activity.

    PubMed

    Lakshmipraba, Jagadeesan; Arunachalam, Sankaralingam; Solomon, Rajadurai Vijay; Venuvanalingam, Ponnambalam; Riyasdeen, Anvarbatcha; Dhivya, Rajakumar; Akbarsha, Mohammad Abdulkader

    2015-01-01

    A series of surfactant-copper(II) Schiff base complexes (1-6) of the general formula, [Cu(sal-R2)2] and [Cu(5-OMe-sal-R2)2], {where, sal=salicylaldehyde, 5-OMe-sal=5-methoxy- salicylaldehyde, and R2=dodecylamine (DA), tetradecylamine (TA), or cetylamine (CA)} have been synthesized and characterized by spectroscopic, ESI-MS, and elemental analysis methods. For a special reason, the structure of one of the complexes (2) was resolved by single crystal X-ray diffraction analysis and it indicates the presence of a distorted square-planar geometry in the complex. Analysis of the binding of these complexes with DNA has been carried out adapting UV-visible-, fluorescence-, as well as circular dichroism spectroscopic methods and viscosity experiments. The results indicate that the complexes bind via minor groove mode involving the hydrophobic surfactant chain. Increase in the length of the aliphatic chain of the ligands facilitates the binding. Further, molecular docking calculations have been performed to understand the nature as well as order of binding of these complexes with DNA. This docking analysis also suggested that the complexes interact with DNA through the alkyl chain present in the Schiff base ligands via the minor groove. In addition, the cytotoxic property of the surfactant-copper(II) Schiff base complexes have been studied against a breast cancer cell line. All six complexes reduced the visibility of the cells but complexes 2, 3, 5, and 6 brought about this effect at fairly low concentrations. Analyzed further, but a small percentage of cells succumbed to necrosis. Of these complexes (6) proved to be the most efficient aptotoxic agent. PMID:24854148

  10. Synthesis, Spectroscopic and Biological Investigations of the Ternary Metal Complexes of Schiff Bases Derived From 2-hydroxy-1-naphthaldehyde and Some Amino Acids

    Microsoft Academic Search

    Y. H. Ebead; H. M. A. Salman; Y. M. Shebany; M. A. Abdellah

    2012-01-01

    In this work the ternary metal complexes of Cu(II) and UO2(II) with some Schiff bases derived from 2-hydroxy-1-naphthaldehyde and some amino acids as a primary ligand and two different heterocyclic bases as a secondary ligand have been synthesised. FT-IR results disclosed that the Schiff bases are coordinated to the central metal ion as a bivalent tridentate ONO donor. Electronic absorption

  11. Synthesis, spectral and antimicrobial studies of rare earth metal complexes with Schiff-base hydrazone containing quinoline moiety

    Microsoft Academic Search

    Khlood S. Abou-Melha; Hanan Faruk

    2008-01-01

    The synthesis and characterization of lanthanide(III) complexes with the Schiff-base hydrazone, o-hydroxyacetophenone-7-chloro-4-quinoline, (HL) are reported. The complexes were characterized by different physicochemical methods: mass spectrometry, H NMR, C NMR, and IR, UV-visible, molar conductance and magnetic studies. They have the stoichiometry [Ln(L)2(NO3)]·nH2O where Ln = La(III), Pr(III), Nd(II), Sm(III), Eu(III) and n = 1–3. The spectra of the complexes were

  12. Thermodecomposition Kinetics of Dy(III) Complex with Schiff Base Derived from Furfural and DL???Alanine

    Microsoft Academic Search

    Yuhua Fan; Caifeng Bi; Jinying Li

    2003-01-01

    A new Schiff base complex of the composition [Dy(C8H8NO3)(NO3)(H2O)]NO3·H2O (C8H8NO3 = furfurylidenealanine) has been synthesized and characterized by elemental analyses, IR, UV and molar conductance. The thermodecomposition kinetics of the complex were investigated under non?isothermal condition. TG and DTG curves indicate that the complex decomposes in four steps. The kinetics of steps (1) and (3) were calculated by a combination of Achar

  13. Structurally diverse copper complexes bearing NNO-tridentate Schiff-base derivatives as efficient catalysts for copolymerization of carbon dioxide and cyclohexene oxide.

    PubMed

    Tsai, Chen-Yen; Huang, Bor-Hunn; Hsiao, Mon-Wei; Lin, Chu-Chieh; Ko, Bao-Tsan

    2014-05-19

    Structurally diverse copper acetate complexes based on NNO-tridentate Schiff-base ligands were synthesized and characterized as mono-, di-, and trinuclear complexes with respect to varied ancillary ligands. Treatment of the ligand precursors (L(1)-H = 2-(1-((2-(dimethylamino)ethyl)imino)ethyl)-4-methylphenol, L(2)-H = 4-chloro-2-(1-((2-(dimethylamino)ethyl)imino)ethyl)phenol, and L(3)-H = 2-(1-((2-(dimethylamino)ethyl)imino)ethyl)-5-methylphenol) with Cu(OAc)2·H2O (1 equiv) in refluxing ethanol afforded five-coordinate mono- or bimetallic copper complexes ([(L(1))Cu(OAc)(H2O)] (1); [(L(2))Cu(OAc)(H2O)] (2); [(L(3))2Cu2(OAc)2] (3)) in high yields. Dinuclear copper acetate analogue [(L(1))2Cu2(OAc)2] (4) resulted from treatment of L(1)-H as the ligand precursor in refluxing anhydrous MeOH with equimolar proportions of metal acetate salt under a dry nitrogen atmosphere. However, a trinuclear complex, [(L(4))2Cu3(OAc)4] (5), was obtained on utilizing 2-(1-((2-(dimethylamino)ethyl)imino)ethyl)-5-methoxyphenol (L(4)-H) as the proligand under the same synthetic route of 1-3; this complex was also synthesized in the reaction of L(4)-H and copper(II) acetate monohydrate in the ratio of 2:3, giving a quantitative yield. All complexes are active catalysts for copolymerization of cyclohexene oxide (CHO) and CO2 without cocatalysts. In particular, dinuclear Cu complex 3 performed satisfactorily to produce polycarbonates with controllable molecular weights and high carbonate linkages. These copper complexes are the first examples that are effective for both CO2/CHO copolymerization and formation of polymers in a controlled fashion. PMID:24802071

  14. A novel centrosymmetric dinuclear cadmium(II) Schiff base complex with unusual bridging carboxylate: Synthesis, crystal structure and luminescence properties

    Microsoft Academic Search

    Shyamapada Shit; Joy Chakraborty; Brajagopal Samanta; Guillaume Pilet; Samiran Mitra

    2009-01-01

    A novel centrosymmetric dinuclear Cd(II) complex [CdL (CH3COO)]2 (1) has been synthesized by the reaction of Cd(CH3COO)2·2H2O with a Schiff base ligand HL [HL=(E)-2-((pyridin-2-yl)methyleneamino)benzoic acid]. Title complex has been systematically characterized by elemental analysis, FT-IR, and thermal studies. Single crystal X-ray structural analysis reveals that Cd(II) centers in 1 adopt distorted monocapped octahedral geometry and held together by rare doubly

  15. Affinity to bovine serum albumin and anticancer activity of some new water-soluble metal Schiff base complexes

    NASA Astrophysics Data System (ADS)

    Asadi, Mozaffar; Asadi, Zahra; Zarei, Leila; Sadi, Somaye Barzegar; Amirghofran, Zahra

    2014-12-01

    Metal Schiff-base complexes show biological activity but they are usually insoluble in water so four new water-soluble metal Schiff base complexes of Na2[M(5-SO3-1,2-salben]; (5-SO3-1,2-salben denoted N,N";-bis(5-sulphosalicyliden)-1,2-diaminobenzylamine and M = Mg, Mn, Cu, Zn) were synthesized and characterized. The formation constants of the metal complexes were determined by UV-Vis absorption spectroscopy. The interaction of these complexes with bovine serum albumin (BSA) was studied by fluorescence spectroscopy. Type of quenching, binding constants, number of binding sites and binding stoichiometries were determined by fluorescence quenching method. The results showed that the mentioned complexes strongly bound to BSA. Thermodynamic parameters indicated that hydrophobic association was the major binding force and that the interaction was entropy driven and enthalpically disfavoured. The displacement experiment showed that these complexes could bind to the subdomain IIA (site I) of albumin. Furthermore the synchronous fluorescence spectra showed that the microenvironment of the tryptophan residues was not apparently changed. Based on the Förster theory of non-radiation energy transfer, the distance between the donor (Trp residues) and the acceptor metal complexes was obtained. The growth inhibitory effect of complexes toward the K562 cancer cell line was measured.

  16. Affinity to bovine serum albumin and anticancer activity of some new water-soluble metal Schiff base complexes.

    PubMed

    Asadi, Mozaffar; Asadi, Zahra; Zarei, Leila; Sadi, Somaye Barzegar; Amirghofran, Zahra

    2014-12-10

    Metal Schiff-base complexes show biological activity but they are usually insoluble in water so four new water-soluble metal Schiff base complexes of Na2[M(5-SO3-1,2-salben]; (5-SO3-1,2-salben denoted N,N'-bis(5-sulphosalicyliden)-1,2-diaminobenzylamine and M=Mg, Mn, Cu, Zn) were synthesized and characterized. The formation constants of the metal complexes were determined by UV-Vis absorption spectroscopy. The interaction of these complexes with bovine serum albumin (BSA) was studied by fluorescence spectroscopy. Type of quenching, binding constants, number of binding sites and binding stoichiometries were determined by fluorescence quenching method. The results showed that the mentioned complexes strongly bound to BSA. Thermodynamic parameters indicated that hydrophobic association was the major binding force and that the interaction was entropy driven and enthalpically disfavoured. The displacement experiment showed that these complexes could bind to the subdomain IIA (site I) of albumin. Furthermore the synchronous fluorescence spectra showed that the microenvironment of the tryptophan residues was not apparently changed. Based on the Förster theory of non-radiation energy transfer, the distance between the donor (Trp residues) and the acceptor metal complexes was obtained. The growth inhibitory effect of complexes toward the K562 cancer cell line was measured. PMID:24996211

  17. Synthesis and Characterization of Some Transition Metal Complexes with Schiff Bases Derived from 2-HYDROXYACETYLACETOPHENONE

    Microsoft Academic Search

    S. A. Shama; H. Omara

    2001-01-01

    Metal chelates of some Schiff bases derived from diamines and 2-hydroxyacetylacetophenone with Cr, Fe, Co, Ni, Cu, and Cd of stoichiometric ratios 1:1 and 2:1 (M:L) have been synthesized and characterized by different spectrophotometric techniques. It is found that the coordination site of ligands differs depending on the kind of metal ions. Thus, Cr, Fe, and Co enter in the

  18. Spectral characterization, electrochemical and anticancer studies on some metal(II) complexes containing tridentate quinoxaline Schiff base

    NASA Astrophysics Data System (ADS)

    Chellaian, Justin Dhanaraj; Johnson, Jijo

    2014-06-01

    Co(II), Ni(II), Cu(II) and Zn(II) complexes of a tridentate ONO donor Schiff base ligand derived from 3-(2-aminoethylamino)quinoxalin-2(1H)-one were synthesized. The ligand and its metal complexes were characterized using elemental analysis, molar conductance, IR, 1H NMR, mass, magnetic susceptibility, electronic spectra and ESR spectral studies. Electrochemical behavior of the synthesized compounds was studied using cyclic voltammetry. The grain size of the synthesized compounds was determined by powder XRD. The Schiff base and its complexes have been screened for their antimicrobial activities against the bacterial species E. coli, K. pneumoniae, P. aeruginosa and S. aureus; fungal species include, A. niger, and C. albicans by disc diffusion method. The results show that the complexes have higher activity than the free ligand. The interaction of the complexes with calf thymus DNA (CT DNA) has been investigated by electronic absorption method. Furthermore, the DNA cleavage activity of the complexes was studied using agarose gel electrophoresis. In vitro anticancer studies of the ligand and its complexes using MTT assay was also done.

  19. A new nano-structured Ni(II) Schiff base complex: synthesis, characterization, optical band gaps, and biological activity

    NASA Astrophysics Data System (ADS)

    Rashad, M. M.; Hassan, A. M.; Nassar, A. M.; Ibrahim, N. M.; Mourtada, A.

    2014-05-01

    New Ni(II) Schiff base complexes [{Ni(L)(H2O)Cl} where HL = 2-((pyridin-3-ylmethylene)amino)phenol] have been synthesized using the reflux and sonochemical methods. The nickel oxide NiO nanopowder was obtained from the metal complexes after calcination at 650 °C for 2 h. The Schiff base complexes and NiO powders were characterized in detail. The HL and its metal complexes were depicted high activity towards microorganism and breast carcinoma cells. The inhibitory activity against breast carcinoma (MCF-7) were detected with IC50 = 5.5, 12.5 and 9.6 for HL, complex (1) and complex (2), respectively. The optical band gap energy was 3.6, 3.0 and 2.37 eV for Ni complexes (1), (2) and NiO, respectively. The microstructure of the formed NiO powders appeared as cubic-like structure. Furthermore, magnetic properties of NiO sample were identified and paramagnetic property was found at a room temperature. The saturation magnetization and coercive force for the NiO sample were 0.47 emu/g and 42.68 Oe, respectively.

  20. Complexes of trivalent metal ions with potentially heptadentate N{sub 4}O{sub 3} Schiff base and amine phenol ligands of varying rigidity

    SciTech Connect

    Yang, L.W.; Liu, S.; Wong, E.; Rettig, S.J.; Orvig, C. [Univ. of British Columbia, Vancouver (Canada)

    1995-04-12

    The synthesis and characterization of several potentially heptadentate N{sub 4}O{sub 3} Schiff bases and amine phenols, as well as a series of their mononuclear and dinuclear complexes with indium and the lanthanides are reported. Schiff bases containing imidazolidine rings were the products of the known condensation reaction of triethylenetetramine with 3 equiv of 5-substituted salicylaldehydes to form H{sub 3}api (5-H-substituent), H{sub 3}Clapi (5-Cl-substituent), or H{sub 3}Brapi (5-Br-substituent); KBH{sub 4} reduction of these Schiff bases gave the appropriate isomeric N{sub 4}O{sub 3} amine phenols H{sub 3}(1,2,4-btt) and H{sub 3}(1,1,4-btt), as well as an acetone adduct, H{sub 3}(1,2,4-ahi). The Schiff bases reacted with 1 equiv of a lanthanide (Ln{sup 3+}) nitrate to produce mononuclear nine-coordinated [Ln(H{sub 3}Xapi)-(NO{sub 3}){sub 3}] complex wherein the ligand adopts a tridentate capping coordination mode, whereas the amine phenols formed mononuclear seven-coordinate complexes with the lanthanides and indium; homodinuclear complexes [LnL]{sub 2} were also obtained with the Schiff bases. The X-ray structures of the Schiff bases H{sub 3}api and H{sub 3}Clapi, the mononuclear amine phenol complexes Yb(1,2,4-btt){center_dot}0.5CH{sub 3}OH and In(1,1,4-btt), and the homodinuclear Schiff base complex [La(Brapi)]{sub 2}{center_dot}2CHCl{sub 3} have been determined.

  1. Preparation and Characterization of Di-, Tri-, and Tetranuclear Schiff Base Complexes Derived from Diamines and 3,4-Dihydroxybenzaldehyde

    PubMed Central

    Abdulghani, Ahlam Jameel; Khaleel, Asmaa Mohammed Noori

    2013-01-01

    A series of new di-, tri-, and tetranuclear Co(II) and Cu(II) complexes of three new diSchiff base ligands were synthesized by two different methods. The first method involved the synthesis of the three ligands from condensation reaction of 3,4-dihydroxybenzaldehyde (L?H2) with ethylenediamine (en), o-phenylenediamine (o-PD), or 4,5-dimethyl-1,2-phenylendiamine (DMPD) in a mole ratio of 2?:?1 followed by the reaction of the resulting Schiff bases ligands with Cu(II) or Co(II) ions in the presence of 2,2?-bipyridyl (L) to form the di- and trinuclear metal complexes. The second method involved the condensation of the copper complex LCu(II)L? (L = 2,2?-bipyridyl, L? = 4-formylbenzene-1,2-bis(olate)) with en, o-PD, or DMPD in a mole ratio of 2?:?1, respectively, followed by reaction with CuCl2 or Cu(ClO4)2 to form di-, tri-, and tetranuclear copper (II) complexes, respectively. The structures of the ligands and metal complexes were characterized by elemental analyses, NMR, and FTIR spectra. The geometries of metal complexes were suggested according to elemental analysis, electronic spectra, thermal analyses, atomic absorption, and magnetic moments and conductivity measurements. PMID:24453995

  2. 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 ?-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 ? lie in the range 0.19-0.37 which indicated the covalent character in metal ligand ‘?' 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.

  3. Synthesis, spectral characterization, molecular modeling, thermal study and biological evaluation of transition metal complexes of a bidentate Schiff base ligand.

    PubMed

    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 -C=S group and nitrogen atoms of -C=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 ?(-1) cm(2) 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 ? lie in the range 0.19-0.37 which indicated the covalent character in metal ligand '?' 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. PMID:23727669

  4. Synthesis, coordination behavior, and investigations of pharmacological effects of some transition metal complexes with isoniazid Schiff bases

    Microsoft Academic Search

    Krishna K. Sharma; Ritu Singh; Nighat Fahmi; R. V. Singh

    2010-01-01

    Two isoniazid Schiff bases, N-isonicotinamido-2-furanketimine (INH-F) and N-isonicotinamido-5-methyl-2-furanketimine (INH-F), possessing potential N and O coordination sites have been prepared by the reaction of isoniazid with 2-acetylfuran and 2-acetyl-5-methylfuran, respectively. Complexes of Pd(II) and Pt(II) have been prepared and characterized by elemental analyses, melting point determinations and electronic, infrared, H NMR, C NMR spectral studies, and X-ray powder diffraction studies. In

  5. OLEDs based on some mixed-ligand terbium carboxylates and zinc complexes with tetradentate Schiff bases: Mechanisms of electroluminescence degradation

    Microsoft Academic Search

    Leonid Lepnev; Andrei Vaschenko; Alexei Vitukhnovsky; Svetlana Eliseeva; Oxana Kotova; Natalia Kuzmina

    2009-01-01

    Mixed-ligand terbium carboxylates—Tb(Carb)3(TPPO)2 (HCarb=HSal (salicylic acid), Hpobz (2-phenoxybenzoic acid); TPPO=triphenylphosphine oxide) and zinc complexes with tetradentate Schiff bases—ZnSB (H2SB=H2SAL1, H2SAL2 (derivatives of salicylic aldehyde); H2MO1, H2MO2 (derivatives of o-vanillin)) were used as electroluminescent (EL) layers in organic light emitting diodes (OLEDs). These devices have undergone reversible and irreversible mechanisms of EL degradation. The reversible one is mainly associated with charge

  6. Synthesis of metal complexes involving Schiff base ligand with methylenedioxy moiety: Spectral, thermal, XRD and antimicrobial studies

    NASA Astrophysics Data System (ADS)

    Sundararajan, M. L.; Jeyakumar, T.; Anandakumaran, J.; Karpanai Selvan, B.

    2014-10-01

    Metal complexes of Zn(II), Cd(II), Ni(II), Cu(II), Fe(III), Co(II), Mn(II) Hg(II), and Ag(I) have been synthesized from Schiff base ligand, prepared by the condensation of 3,4-(methylenedioxy)aniline and 5-bromo salicylaldehyde. All the compounds have been characterized by using elemental analysis, molar conductance, FT-IR, UV-Vis, 1H NMR, 13C NMR, mass spectra, powder XRD and thermal analysis (TG/DTA) technique. The elemental analysis suggests the stoichiometry to be 1:1 (metal:ligand). The FT-IR, 1H NMR, 13C NMR and UV-Vis spectral data suggest that the ligand coordinate to the metal atom by imino nitrogen and phenolic oxygen as bidentate manner. Mass spectral data further support the molecular mass of the compounds and their structure. Powder XRD indicates the crystalline state and morphology of the ligand and its metal complexes. The thermal behaviors of the complexes prove the presence of lattice as well as coordinated water molecules in the complexes. Melting point supports the thermal stability of all the compounds. The in vitro antimicrobial effects of the synthesized compounds were tested against five bacterial and three fungal species by well diffusion method. Antioxidant activities have also been performed for all the compounds. Metal complexes show more biological activity than the Schiff base.

  7. Charge and Spin States in Schiff Base Metal Complexes with a Disiloxane Unit Exhibiting a Strong Noninnocent Ligand Character: Synthesis, Structure, Spectroelectrochemistry, and Theoretical Calculations.

    PubMed

    Cazacu, Maria; Shova, Sergiu; Soroceanu, Alina; Machata, Peter; Bucinsky, Lukas; Breza, Martin; Rapta, Peter; Telser, Joshua; Krzystek, J; Arion, Vladimir B

    2015-06-15

    Mononuclear nickel(II), copper(II), and manganese(III) complexes with a noninnocent tetradentate Schiff base ligand containing a disiloxane unit were prepared in situ by reaction of 3,5-di-tert-butyl-2-hydroxybenzaldehyde with 1,3-bis(3-aminopropyl)tetramethyldisiloxane followed by addition of the appropriate metal(II) salt. The ligand H2L resulting from these reactions is a 2:1 condensation product of 3,5-di-tert-butyl-2-hydroxybenzaldehyde with 1,3-bis(3-aminopropyl)tetramethyldisiloxane. The resulting metal complexes, NiL·0.5CH2Cl2, CuL·1.5H2O, and MnL(OAc)·0.15H2O, were characterized by elemental analysis, spectroscopic methods (IR, UV-vis, X-band EPR, HFEPR, (1)H NMR), ESI mass spectrometry, and single crystal X-ray diffraction. Taking into account the well-known strong stabilizing effects of tert-butyl groups in positions 3 and 5 of the aromatic ring on phenoxyl radicals, we studied the one-electron and two-electron oxidation of the compounds using both experimental (chiefly spectroelectrochemistry) and computational (DFT) techniques. The calculated spin-density distribution and localized orbitals analysis revealed the oxidation locus and the effect of the electrochemical electron transfer on the molecular structure of the complexes, while time-dependent DFT calculations helped to explain the absorption spectra of the electrochemically generated species. Hyperfine coupling constants, g-tensors, and zero-field splitting parameters have been calculated at the DFT level of theory. Finally, the CASSCF approach has been employed to theoretically explore the zero-field splitting of the S = 2 MnL(OAc) complex for comparison purposes with the DFT and experimental HFEPR results. It is found that the D parameter sign strongly depends on the metal coordination geometry. PMID:26030801

  8. Co(II), Ni(II) and Cu(II) complexes with coumarin-8-yl Schiff-bases: Spectroscopic, in vitro antimicrobial, DNA cleavage and fluorescence studies

    NASA Astrophysics Data System (ADS)

    Patil, Sangamesh A.; Unki, Shrishila N.; Kulkarni, Ajaykumar D.; Naik, Vinod H.; Badami, Prema S.

    2011-09-01

    A new series of Co(II), Ni(II) and Cu(II) complexes of the type ML·2H 2O of Schiff-bases derived from m-substituted thiosemicarbazides and 8-acetyl-7-hydroxy-4-methylcoumarin have been synthesized and characterized by spectroscopic studies. Schiff-bases exhibit thiol-thione tautomerism wherein sulphur plays an important role in the coordination. The coordination possibility of the Schiff-bases towards metal ions have been proposed in the light of elemental analyses, spectral (IR, UV-vis, FAB-mass, ESR and fluorescence), magnetic and thermal studies. The low molar conductance values in DMF indicate that, the metal complexes are non-electrolytes. The cyclic voltammetric studies suggested that, the Cu(II) and Ni(II) complexes are of single electron transfer quasi-reversible nature. The Schiff-bases and its metal complexes have been evaluated for their in vitro antibacterial ( Escherichia coli, Staphilococcus aureus, Bascillus subtilis and Salmonella typhi) and antifungal activities ( Candida albicans, Cladosporium and Aspergillus niger) by MIC method. The Schiff-base I and its metal complexes exhibited DNA cleavage activity on isolated DNA of A. niger.

  9. Synthesis, spectral characterization, thermal analysis, molecular modeling and antimicrobial activity of new potentially N2O2 azo-dye Schiff base complexes

    NASA Astrophysics Data System (ADS)

    Alaghaz, Abdel-Nasser M. A.; Ammar, Yousry A.; Bayoumi, Hoda A.; Aldhlmani, Sharah A.

    2014-09-01

    The azo-dye Schiff's base of N2O2 dibasic ligand, H2L [N,N?-bis(5-(4-sulfanilamidophenylazosalicylidene)ethylenediamine] was prepared by the condensation of ethylenediamine with [5-(4-sulfanilamidophenylazo-salicylaldehyde] in ethanol. New complexes of with metal ions Cu(II), Ni(II), Co(II), Mn(II), Zn(II), Cd(II), Pt(IV), Fe(III) and Cr(III) are synthesized. Elemental, spectroscopic and thermal analyses as well as conductivity and magnetic susceptibility measurements are used to elucidate the structure of the newly prepared metal complexes. The azo-dye Schiff's base behaves as a di-negative N2O2 tetradentate ligand. The metal complexes exhibited square planar, tetrahedral and octahedral geometrical arrangements, the molar conductivity data indicates that all complexes are neutral. The thermogravimetry (TG) and differential thermoanalysis (DTA) of the Cu(II), Mn(II), Cr(III) and Co(II) complexes were carried out in the range of 30-800 °C. The complexes were decomposed in one and two stages of the Cu(II), Mn(II), Cr(III) and Co(II) complexes, respectively. Also, decomposition of the synthesized complexes is related to the Schiff's base characteristics. The thermal decomposition of the studied reactions was first order. The kinetic parameters for the decomposition steps in Cu(II), Mn(II), Cr(III) and Co(II) complexes thermograms have been calculated using Broido's method. In molecular modeling the geometries of azo-dye Schiff base ligand H2L and its metal(II/III/IV) complexes were fully optimized with respect to the energy using the 6-31G basis set. Antimicrobial activities of the azo-dye Schiff's base ligand and its corresponding metal complexes were screened against various organisms. The azo-dye Schiff's base ligand and some of its complexes were found to be biologically inactive.

  10. Synthesis, characterization and biological activity of transition metal complexes with Schiff bases derived from 2-nitrobenzaldehyde with glycine and methionine

    NASA Astrophysics Data System (ADS)

    Singh, Bibhesh K.; Rajour, Hemant K.; Prakash, Anant

    Schiff bases derived from 2-nitrobenzaldehyde with amino acids (glycine, methionine) and their Co(II), Ni(II) and Cu(II) complexes have been synthesized and characterized by various physico-chemical techniques. From spectral studies, it has been concluded that the ligands acts as bidentate molecule, coordinates metal through azomethine nitrogen and carboxylate oxygen. Mass spectrum explains the successive degradation of the molecular species in solution and justifies ML2 complexes. X-ray powder diffraction helps to determine the cell parameters of the complexes. Molecular structure of the complexes has been optimized by MM2 calculations and suggests a square planar geometry. The ligands and their metal complexes have been tested in vitro against Streptococcus, Staph, Staphylococcus aureus and Escherchia coli bacteria in order to assess their antibacterial potential. The results indicate that the biological activity increases on complexation.

  11. A comparative study of cytotoxicity and interaction with DNA/protein of five transition metal complexes with Schiff base ligands.

    PubMed

    Niu, Meiju; Hong, Min; Chang, Guoliang; Li, Xiao; Li, Zhen

    2015-07-01

    Five transition metal complexes NiL(1)2 (1), CuL(1)2 (2), ZnL(1)2 (3), [MnL(1)2(N3)]n·nCH2Cl2 (4), CuL(2)2 (5) {HL(1)=3-{[2-(2-hydroxy-ethoxy)-ethylimino]-methyl}-naphthalen-2-ol, HL(2)=2-{[2-(2-hydroxy-ethoxy)-ethylimino]-methyl}-phenol} have been synthesized and fully characterized. In all of the complexes, the ligands coordinated to the metal ion in a negative fashion via O and N donor atoms. The X-ray structures of nickel complex 1 and copper complexes 2 and 5 are four-coordinated monomers and show slightly distorted square-planar geometry in the vicinity of the central metal atom. Zinc complex 3 exhibits a four-coordinated tetrahedral structure. Differently, manganese complex 4 reveals a six-coordinated octahedral structure, one-dimensional chain is linked by azide in the end-to-end mode. In vitro cytotoxicity of these complexes to various tumor cell lines was assayed by the MTT method. The results showed that most of these metal-Schiff base complexes exhibited enhanced cytotoxicity than Schiff base ligands, which clearly implied a positive synergistic effect. Moreover, these complexes appeared to be selectively active against certain cell lines. The interactions of these metal complexes with CT-DNA were investigated by UV-vis, fluorescence and CD spectroscopy, the results indicated that these complexes are metallointercalators and can interact with CT-DNA. The study of interaction between complexes and BSA indicated that all of the complexes could quench the intrinsic fluorescence of BSA in a static quenching process. PMID:25974907

  12. Synthesis, Spectral Characterization, and Biological Evaluation of Transition Metal Complexes of Bidentate N, O Donor Schiff Bases

    PubMed Central

    Sumrra, Sajjad Hussain; Ambreen, Sabahat; Imran, Muhammad; Danish, Muhammad; Rehmani, Fouzia Sultana

    2014-01-01

    New series of three bidentate N, O donor type Schiff bases (L1)–(L3) were prepared by using ethylene-1,2-diamine with 5-methyl furfural, 2-anisaldehyde, and 2-hydroxybenzaldehyde in an equimolar ratio. These ligands were further complexed with Co(II), Cu(II), Ni(II), and Zn(II) metals to produce their new metal complexes having an octahedral geometry. These compounds were characterized on the basis of their physical, spectral, and analytical data. Elemental analysis and spectral data of the uncomplexed ligands and their metal(II) complexes were found to be in good agreement with their structures, indicating high purity of all the compounds. All ligands and their metal complexes were screened for antimicrobial activity. The results of antimicrobial activity indicated that metal complexes have significantly higher activity than corresponding ligands. This higher activity might be due to chelation process which reduces the polarity of metal ion by coordinating with ligands. PMID:25147493

  13. Synthesis, Characterization and Biological Properties of Anions of Bivalent Transition Metal [Co(II) and Ni(II)] Complexes With Acylhydrazine Derived ONO Donor Schiff Bases

    PubMed Central

    Farooq, M. A.; Iqbal, M. S.

    2000-01-01

    Some acylhydrazine derived ONO donor Schiff bases and their Co(II) and Ni(II) complexes have been prepared having the same metal ion (cation) but different anions. These synthesized metal(II) complexes have been characterized on the basis of their elemental analyses, magnetic moment, molar conductance, and IR and electronic spectral data. All of the Schiff base ligands function as tridentates and the deprotonated enolic form is preferred for coordination. In order to evaluate the effect of anions on the bactericidal activity, these synthesized complexes, in comparison to the uncomplexed Schiff bases have been screened against bacterial species., Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa and the results are reported. PMID:18475936

  14. Crystal Structure, Cytotoxicity and Interaction with DNA of Zinc (II) Complexes with o-Vanillin Schiff Base Ligands

    PubMed Central

    Niu, Mei-Ju; Li, Zhen; Chang, Guo-Liang; Kong, Xiang-Jin; Hong, Min; Zhang, Qing-fu

    2015-01-01

    Two new zinc complexes, Zn(HL1)2 (1) and [Zn2(H2L2)(OAc)2]2 (2) [H2L1 = Schiff base derived from o-vanillin and (R)-(+)-2-amino-3-phenyl-1-propanol, H3L2 = Schiff base derived from o-vanillin and 2-amino-2-ethyl-1,3-propanediol], have been synthesized and characterized by single crystal X-ray diffraction, elemental analyses, TG analyses, solid fluorescence, IR, UV-Vis and circular dichroism spectra. The structural analysis shows that complex 1 has a right-handed double helical chain along the crystallographic b axis. A homochiral 3D supramolecular architecture has been further constructed by intermolecular C-H··· ?, O-H···O and C-H···O interactions. Complex 2 includes two crystallographically independent binuclear zinc molecules. The two binuclear zinc molecules are isostructural. The 2-D sheet supramolecular structure was formed by intermolecular hydrogen bonding interaction. The fluorescence of ligands and complexes in DMF at room temperature are studied. The interactions of two complexes with calf thymus DNA (CT-DNA) are investigated using UV-Vis, CD and fluorescence spectroscopy. The results show that complex 1 exhibits higher interaction with CT-DNA than complex 2. In addition, in vitro cytotoxicity of the complexes towards four kinds of cancerous cell lines (A549, HeLa, HL-60 and K562) were assayed by the MTT method. Investigations on the structures indicated that the chirality and nuclearity of zinc complexes play an important role on cytotoxic activity. PMID:26114437

  15. Crystal Structure, Cytotoxicity and Interaction with DNA of Zinc (II) Complexes with o-Vanillin Schiff Base Ligands.

    PubMed

    Niu, Mei-Ju; Li, Zhen; Chang, Guo-Liang; Kong, Xiang-Jin; Hong, Min; Zhang, Qing-Fu

    2015-01-01

    Two new zinc complexes, Zn(HL1)2 (1) and [Zn2(H2L2)(OAc)2]2 (2) [H2L1 = Schiff base derived from o-vanillin and (R)-(+)-2-amino-3-phenyl-1-propanol, H3L2 = Schiff base derived from o-vanillin and 2-amino-2-ethyl-1,3-propanediol], have been synthesized and characterized by single crystal X-ray diffraction, elemental analyses, TG analyses, solid fluorescence, IR, UV-Vis and circular dichroism spectra. The structural analysis shows that complex 1 has a right-handed double helical chain along the crystallographic b axis. A homochiral 3D supramolecular architecture has been further constructed by intermolecular C-H··· ?, O-H···O and C-H···O interactions. Complex 2 includes two crystallographically independent binuclear zinc molecules. The two binuclear zinc molecules are isostructural. The 2-D sheet supramolecular structure was formed by intermolecular hydrogen bonding interaction. The fluorescence of ligands and complexes in DMF at room temperature are studied. The interactions of two complexes with calf thymus DNA (CT-DNA) are investigated using UV-Vis, CD and fluorescence spectroscopy. The results show that complex 1 exhibits higher interaction with CT-DNA than complex 2. In addition, in vitro cytotoxicity of the complexes towards four kinds of cancerous cell lines (A549, HeLa, HL-60 and K562) were assayed by the MTT method. Investigations on the structures indicated that the chirality and nuclearity of zinc complexes play an important role on cytotoxic activity. PMID:26114437

  16. Structure and physico-chemical properties of hexadentate Schiff base zinc complexes derived from salicylaldehydes and triethylenetetramine*1

    NASA Astrophysics Data System (ADS)

    Chantarasiri, Nuanphun; Ruangpornvisuti, Vithaya; Muangsin, Nongnuj; Detsen, Hussadee; Mananunsap, Thussanee; Batiya, Chureephon; Chaichit, Narongsak

    2004-09-01

    Two hexadentate Schiff base zinc complexes, ZnSal 2trien and ZnVan 2trien, where Sal=salicylaldehyde, Van= o-vanillin, and trien=triethylenetetramine, have been synthesized by the reaction between salicylaldehydes, triethylenetetramine and zinc acetate. The structure of ZnSal 2trien and ZnVan 2trien were determined by single crystal X-ray crystallography. It was found that both ZnSal 2trien and ZnVan 2trien have a bent-shaped structure. Properties of the complexes were examined using differential scanning calorimetry, polarized optical microscopy and small angle X-ray scattering. Protonation constants of the ligands Sal 2trien and Van 2trien and stability constants of their zinc complexes were determined by potentiometric titration. Binding energies of ZnSal 2trien and ZnVan 2trien complexes were obtained by quantum chemical calculations.

  17. Synthesis, characterization and thermodynamics of complex formation of some new Schiff base ligands with some transition metal ions and the adduct formation of zinc Schiff base complexes with some organotin chlorides

    NASA Astrophysics Data System (ADS)

    Asadi, Mozaffar; Asadi, Zahra; Torabi, Susan; Lotfi, Najmeh

    Four new complexes, [M(Salpyr)] where Salpyr = N,N'-bis(Salicylidene)-2,3- and 3,4-diiminopyridine and M = Co, Cu, Mn, Ni and Zn were synthesized and characterized by 1H NMR, IR spectroscopy, elemental analysis and UV-vis spectrophotometry. UV-vis spectrophotometric study of the adduct formation of the zinc(II) complexes, [Zn(2,3-Salpyr)] and [Zn(3,4-Salpyr)], as donor with R2SnCl2 (R = methyl, phenyl, n-butyl), PhSnCl3 and Bu3SnCl as acceptors has been investigated in methanol, as solvent. The formation constants and the thermodynamic free energies were measured using UV-vis spectrophotometry. Titration of the organotin chlorides with Zn(II) complexes at various temperatures (T = 283-313 K) leads to 1:1 adduct formation. The results show that the formation constants were decreased by increasing the temperature. The trend of the reaction of RnSnCl4-n as acceptors toward given zinc complexes was as follows: PhSnCl3 > Me2SnCl2 > Ph2SnCl2 > Bu2SnCl2 > Bu3SnCl By considering the formation constants and the ?G° of the complex formation for the Schiff base as donor and the M(II) as acceptor, the following conclusion was drawn: the formation constant for a given Schiff base changes according to the following trend: Ni > Cu > Co > Zn > Mn

  18. Investigation of the solid-state conductivity and the potentiometric stability constant relationships of new amino acid-Schiff bases and their complexes

    Microsoft Academic Search

    Nur?en Sarì; Perihan Gürkan

    2003-01-01

    CuII, NiII and CoII complexes of new tridentate amino acid-Schiff bases derived from furfural and DL-alanine, DL-valine and DL-phenylalanine were prepared and characterized by analytical, spectroscopic, (i.r., u.v.–vis., 1H-n.m.r and 13C-n.m.r) techniques, molar conductivity, magnetic and thermal measurements. Protonation constants of the Schiff bases and stability constants of the complexes have been determined potentiometrically in water. Solid-state conductivities of the

  19. Novel Asymmetric Tetradentate Schiff Base Ligands Derived from 6-Metwia-Formyl4Hydroxy2-(1H)-Quinolone and Their Metal Complexes

    Microsoft Academic Search

    Adel A. A. Emara

    1999-01-01

    Novel asymmetric, tetradentate, dibasic Schiff base ligands were synthesized by the condensation of the half-unit Schiff base ligand 3-[o-aminophenyliminomethyl]-4-hydroxy-6-methyl-2-(1H)-quinolone with acetylacetone and salicylaldehyde. Cu(II), Ni(II), UO2 (VI) and Fe(III) complexes of both ligands were prepared using different salts in the case of Cu(II) and Ni(II) cations The structures of the ligands and the complexes were elucidated by chemical analyses, IR,

  20. 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.

  1. Influence of chirality of V(V) Schiff base complexes on DNA, BSA binding and cleavage activity.

    PubMed

    Khan, Noor-ul H; Pandya, Nirali; Maity, Nabin Ch; Kumar, Manoj; Patel, Rajesh M; Kureshy, Rukhsana I; Abdi, Sayed H R; Mishra, Sandhya; Das, Satyabrata; Bajaj, Hari C

    2011-10-01

    New chiral V(V) Schiff base complexes (S)-[VO(OMe)L] and (R)-[VO(OMe)L] were synthesized and characterized by microanalysis, infrared (IR), UV-Visible, Circular dichroism (CD) spectroscopy and single crystal X-ray studies. The interaction of these complexes with calf thymus (CT) DNA and bovine serum albumin (BSA) protein showed chiral expression DNA/protein binding strength. The influence of chirality was also observed in cytotoxicity assay of Hep 2 cells. (R)-[VO(OMe)L] enantiomer exhibited higher binding constant (5 ± 1 × 10(5) M(-1)) as compared to (S)-[VO(OMe)L] (8 ± 1 × 10(4) M(-1)). The fluorescence quenching, thermal melting and viscosity data suggest DNA surface and/or groove binding nature of the complexes and electrophoresis studies also showed greater activity for (R)-[VO(OMe)L] in cleaving DNA and protein as against (S)-[VO(OMe)L]. PMID:21875762

  2. Synthesis and characterization of metal complexes of Schiff base ligand derived from imidazole-2-carboxaldehyde and 4-aminoantipyrine.

    PubMed

    Selwin Joseyphus, R; Shiju, C; Joseph, J; Justin Dhanaraj, C; Arish, D

    2014-12-10

    The Co(II), Ni(II), Cu(II) and Zn(II) complexes of the Schiff base derived from imidazole-2-carboxaldehyde and 4-aminoantipyrine were synthesized. These compounds were characterized by elemental analysis, IR, mass, (1)H NMR, electronic spectra, magnetic moment, molar conductance, thermal analysis, powder XRD and SEM. The analytical data show that the metal to ligand ratio is 1:1. The IR results show that the ligand acts as a bidentate donor coordinating through the azomethine nitrogen and imidazole nitrogen atoms. From the electronic spectra and magnetic moment value predicts the geometry of the complexes. The surface morphology of the compounds was studied by SEM. The compounds were screened for their antibacterial activity and antifungal activity using Kirby Bayer disc diffusion method. The DNA cleavage and superoxide dismutase activities of the compounds were investigated. The anticancer activities of the complexes have been carried out towards HeLa and HCT116 cancer cells. PMID:24934973

  3. Synthesis and characterization of metal complexes of Schiff base ligand derived from imidazole-2-carboxaldehyde and 4-aminoantipyrine

    NASA Astrophysics Data System (ADS)

    Selwin Joseyphus, R.; Shiju, C.; Joseph, J.; Justin Dhanaraj, C.; Arish, D.

    2014-12-01

    The Co(II), Ni(II), Cu(II) and Zn(II) complexes of the Schiff base derived from imidazole-2-carboxaldehyde and 4-aminoantipyrine were synthesized. These compounds were characterized by elemental analysis, IR, mass, 1H NMR, electronic spectra, magnetic moment, molar conductance, thermal analysis, powder XRD and SEM. The analytical data show that the metal to ligand ratio is 1:1. The IR results show that the ligand acts as a bidentate donor coordinating through the azomethine nitrogen and imidazole nitrogen atoms. From the electronic spectra and magnetic moment value predicts the geometry of the complexes. The surface morphology of the compounds was studied by SEM. The compounds were screened for their antibacterial activity and antifungal activity using Kirby Bayer disc diffusion method. The DNA cleavage and superoxide dismutase activities of the compounds were investigated. The anticancer activities of the complexes have been carried out towards HeLa and HCT116 cancer cells.

  4. Cd(II) and Cu(II) complexes of polydentate Schiff base ligands: synthesis, characterization, properties and biological activity

    Microsoft Academic Search

    Aysegul Golcu; Mehmet Tumer; Havva Demirelli; R. Alan Wheatley

    2005-01-01

    We report the synthesis of the Schiff base ligands, 4-[(4-bromo-phenylimino)-methyl]-benzene-1,2,3-triol (A1), 4-[(3,5-di-tert-butyl-4-hydroxy-phenylimino)-methyl]-benzene-1,2,3-triol (A2), 3-(p-tolylimino-methyl)-benzene-1,2-diol (A3), 3-[(4-bromo-phenylimino)-methyl]-benzene-1,2-diol (A4), and 4-[(3,5-di-tert-butyl-4-hydroxy-phenylimino)-methyl]-benzene-1,3-diol (A5), and their Cd(II) and Cu(II) metal complexes, stability constants and potentiometric studies. The structure of the ligands and their complexes was investigated using elemental analysis, FT-IR, UV–Vis, 1H and 13C NMR, mass spectra, magnetic susceptibility and conductance measurements. In the

  5. Solution combustion synthesis using Schiff-base aluminum complex without fuel and optical property investigations of alumina nanoparticles

    NASA Astrophysics Data System (ADS)

    Salehi, Mehdi; Arabsarhangi, Ehsan

    2015-05-01

    Synthesis of alumina nanomaterials via a solution combustion technique using Schiff base aluminum (III) complex at 820 and 950 °C for 4 h was performed successfully. The synthesis procedure was performed using the complex in the absence and presence of urea and glycine as fuel for comparison. The obtained data showed that the procedure without using fuel resulted in a better phase and morphology. To investigate the phase formation, powder X-ray diffraction technique was used. Also, SEM micrographs were used to investigate the morphology of the obtained materials. The optical properties of the obtained materials were studied by FTIR spectra. According to the PXRD data, it was found that with annealing at 950 °C, the phase formation of the obtained materials showed cubic crystal structure with cell parameter a = 3.14 Å for gamma phase. Also, by annealing at 820 °C using fuels for 4 h, the main phase was found to be in gamma.

  6. Synthesis, crystal structures, and spectral characterization of tetranuclear Mn(II) complex with a new Schiff base ligand and molecular dynamics studies on inhibition properties of such Schiff base

    NASA Astrophysics Data System (ADS)

    Liu, Jie; Liu, Zheng; Yuan, Shuai; Liu, Jin

    2013-04-01

    A new Schiff base ligand H2L (3,5-dibromosalicylaldehyde pyridine-2-formyl hydrazone) and a new tetra-nuclear coordination complex [Mn4(L)4(DMF)4] (1) have been synthesized and characterized by spectral method (IR), fluorescence spectra, and elemental analysis. Structural characterization of the complex has been done by single-crystal X-ray diffraction analysis. Structural analysis reveals that the metal centers in complex [Mn4(L)4(DMF)4](1) exhibit distorted tetragonal-bipyramid coordination geometry, and each metal ion is coordinated by two mutually perpendicular Schiff base ligands (H2L) and one solvent DMF. The molecular dynamics (MDs) simulations method was performed to study the adsorption behavior of the H2L molecules on metal surface. The results show that the H2L molecules could adsorb on the metal surface firmly through several reactive sites. The analysis of pair correlation functions indicates that chemical bonds are formed between the oxygen nitrogen atoms of H2L molecules and the Fe atoms of Fe surface. These cause the result that H2L molecules interact with metal surface strongly and therefore have excellent corrosion inhibition performance.

  7. Spectroscopic studies and biological evaluation of some transition metal complexes of azo Schiff-base ligand derived from (1-phenyl-2,3-dimethyl-4-aminopyrazol-5-one) and 5-((4-chlorophenyl)diazenyl)-2-hydroxybenzaldehyde

    NASA Astrophysics Data System (ADS)

    Anitha, C.; Sheela, C. D.; Tharmaraj, P.; Sumathi, S.

    2012-10-01

    A series of metal(II) complexes of VO(II), Co(II), Ni(II), Cu(II) and Zn(II) have been synthesized from the azo Schiff base ligand 4-((E)-4-((E)-(4-chlorophenyl)diazenyl)-2-hydroxybenzylideneamino)-1,5-dimethyl-2-phenyl-1H-pyrazol-3(2H)-one (CDHBAP) and characterized by elemental analysis, spectral (IR, UV-Vis, 1H NMR, ESR and EI-mass), magnetic moment measurements, molar conductance, DNA, SEM, X-ray crystallography and fluorescence studies. The electronic absorption spectra and magnetic susceptibility measurements of the complexes indicate square pyramidal geometry for VO(II) and octahedral geometry for all the other complexes. The important infrared (IR) spectral bands corresponding to the active groups in the ligand and the solid complexes under investigation were studied and implies that CDHBAP is coordinated to the metal ions in a neutral tridentate manner. The redox behavior of copper(II) and vanadyl(II) complexes have been studied by cyclic voltammetry. The nuclease activity of the above metal(II) complexes shows that the complexes cleave DNA. All the synthesized complexes can serve as potential photoactive materials as indicated from their characteristic fluorescence properties. The antibacterial and antifungal activities of the synthesized ligand and its metal complexes were screened against bacterial species (Staphylococcus aureus, Salmonella typhi, Escherichia coli, Bacillus subtilis, Shigella sonnie) and fungi (Candida albicans, Aspergillus niger, Rhizoctonia bataicola). Amikacin and Ketoconozole were used as references for antibacterial and antifungal studies. The activity data show that the metal complexes have a promising biological activity comparable with the parent Schiff base ligand against bacterial and fungal species. The second harmonic generation (SHG) efficiency of the ligand was measured and the NLO (non-linear optical) properties of the ligand are expected to result in the realization of advanced optical devices in optical fiber communication (OFC) and optical computing. The SEM image of the copper(II) complex implies that the size of the particles is 1 ?m.

  8. Electroless deposition of vanadium–Schiff base complex onto carbon nanotubes modified glassy carbon electrode: Application to the low potential detection of iodate, periodate, bromate and nitrite

    Microsoft Academic Search

    Abdollah Salimi; Hussein Mamkhezri; Sajjad Mohebbi

    2006-01-01

    The multiwall carbon nanotubes (MWCNTs) were used as an immobilization matrix to incorporate vanadium-Schiff base complex as electron transfer mediator onto a glassy carbon electrode surface. First, the preheated glassy carbon was subjected to abrasive immobilization of MWCNTs by gently rubbing the electrode surface on a filter paper supporting the carbon nanotubes. Second, the electrode surface was modified with casting

  9. Synthesis, reactivity, and coordination chemistry relevant to the copolymerization of CO2 and epoxides by first row transition metal schiff base complexes

    E-print Network

    Frantz, Eric Benjamin

    2009-05-15

    the copolymerization of CO2 and epoxide to form aliphatic polycarbonates. A new chromium(III) Schiff base complex has been synthesized and evaluated for its ability to catalyze the formation of polymer. The ligand employed bears an N2O2 coordination sphere identical...

  10. Iron(III) complexes of a pyridoxal schiff base for enhanced cellular uptake with selectivity and remarkable photocytotoxicity.

    PubMed

    Basu, Uttara; Pant, Ila; Hussain, Akhtar; Kondaiah, Paturu; Chakravarty, Akhil R

    2015-04-20

    Iron(III) complexes of pyridoxal (vitamin B6, VB6) or salicylaldehyde Schiff bases and modified dipicolylamines, namely, [Fe(B)(L)](NO3) (1-5), where B is phenyl-N,N-bis((pyridin-2-yl)methyl)methanamine (phbpa in 1), (anthracen-9-yl)-N,N-bis((pyridin-2-yl)methyl)methanamine (anbpa in 2, 4) and (pyren-1-yl)-N,N-bis((pyridin-2-yl)methyl)methanamine (pybpa in 3, 5) (H2L(1) is 3-hydroxy-5-(hydroxymethyl)-4-(((2-hydroxyphenyl)imino)methyl)-2-methylpyridine (1-3) and H2L(2) is 2-[(2-hydroxyphenyl-imino)methyl]phenol), were prepared and their uptake in cancer cells and photocytotoxicity were studied. Complexes 4 and 5, having a non-pyridoxal Schiff base, were prepared to probe the role of the pyridoxal group in tumor targeting and cellular uptake. The PF6 salt (1a) of complex 1 is structurally characterized. The complexes have a distorted six-coordinate FeN4O2 core where the metal is in the +3 oxidation state with five unpaired electrons. The complexes display a ligand to metal charge transfer band near 520 and 420 nm from phenolate to the iron(III) center. The photophysical properties of the complexes are explained from the time dependent density functional theory calculations. The redox active complexes show a quasi-reversible Fe(III)/Fe(II) response near -0.3 V vs saturated calomel electrode. Complexes 2 and 3 exhibit remarkable photocytotoxicity in various cancer cells with IC50 values ranging from 0.4 to 5 ?M with 10-fold lower dark toxicity. The cell death proceeded by the apoptotic pathway due to generation of reactive oxygen species upon light exposure. The nonvitamin complexes 4 and 5 display 3-fold lower photocytotoxicity compared to their VB6 analogues, possibly due to preferential and faster uptake of the vitamin complexes in the cancer cells. Complexes 2 and 3 show significant uptake in the endoplasmic reticulum, while complexes 4 and 5 are distributed throughout the cells without any specific localization pattern. PMID:25849848

  11. Antimicrobial efficacy of phenanthrenequinone based Schiff base complexes incorporating methionine amino acid: structural elucidation and in vitro bio assay.

    PubMed

    Arun, Thesingu Rajan; Raman, Natarajan

    2014-06-01

    This work focuses the synthesis and characterization of few novel mixed ligand Schiff base metal complexes and their biological activities. For deriving the structural aspects, spectral techniques such as FT-IR, UV-Vis., (1)H NMR, Raman, EPR and the physicochemical characterizations including elemental analysis, molar conductance and magnetic susceptibility method have been involved. All the complexes adopt square planar geometry. DNA binding ability of these complexes has been explored using diverse techniques viz. UV-Vis. absorption, fluorescence spectroscopy, viscometry and cyclic voltammetry. These studies prove that CT-DNA binding of the complexes follows the intercalation mode. Comparative DNA oxidative cleavage ability of the complexes has been done under ultraviolet photo radiation on pUC19 DNA. In addition, the biocidal action of the complexes has been investigated against few pathogenic bacteria and fungi by disc diffusion method. Importantly, the amylase inhibition activity of Cu(II) complex has been explored. The amylase inhibition property has been found to be increased upon increasing the complex concentration. PMID:24632238

  12. Antimicrobial efficacy of phenanthrenequinone based Schiff base complexes incorporating methionine amino acid: Structural elucidation and in vitro bio assay

    NASA Astrophysics Data System (ADS)

    Arun, Thesingu Rajan; Raman, Natarajan

    2014-06-01

    This work focuses the synthesis and characterization of few novel mixed ligand Schiff base metal complexes and their biological activities. For deriving the structural aspects, spectral techniques such as FT-IR, UV-Vis., 1H NMR, Raman, EPR and the physicochemical characterizations including elemental analysis, molar conductance and magnetic susceptibility method have been involved. All the complexes adopt square planar geometry. DNA binding ability of these complexes has been explored using diverse techniques viz. UV-Vis. absorption, fluorescence spectroscopy, viscometry and cyclic voltammetry. These studies prove that CT-DNA binding of the complexes follows the intercalation mode. Comparative DNA oxidative cleavage ability of the complexes has been done under ultraviolet photo radiation on pUC19 DNA. In addition, the biocidal action of the complexes has been investigated against few pathogenic bacteria and fungi by disc diffusion method. Importantly, the amylase inhibition activity of Cu(II) complex has been explored. The amylase inhibition property has been found to be increased upon increasing the complex concentration.

  13. 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.

    PubMed

    Shebl, Magdy

    2009-07-15

    A new bis(tridentate NO2) Schiff base ligand, H(4)L, 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, (1)H 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. PMID:19345138

  14. 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.

  15. Investigation of Dipodal oxy-Schiff base and its salen and salophen Fe(III)/Cr(III)/Mn(III) Schiff bases (N2O2) caped complexes and their magnetic and thermal behaviors

    NASA Astrophysics Data System (ADS)

    Çelikbilek, ?eyma; Koç, Ziya Erdem

    2014-05-01

    Six new dinuclear Fe(III)/Cr(III)/Mn(III) complexes have been involved tetradentate (N2O2) Schiff bases (salenH2) and (salophenH2) with 2,4-bis(4-hydroxyphenylimino-4?-formylphenoxy)-6-methoxy-1,3,5-triazine have been synthesized. The complexes were characterized as high-spin (S = 5/2) distorted trigonal bipyramidal salen/salophenFe(III) bridged, distorted trigonal bipyramidal (S = 3/2) salen/salophenCr(III) and high-spin distorted trigonal bipyramidal (S = 2) salen/salophenMn(III) by OH- groups. The structures of ligand and complexes were identified by using elemental analysis, thermal analysis, magnetic susceptibility, LC-MS, ICP-AES, 1H NMR and FT-IR spectral data.

  16. Synthesis, spectral characterization and DNA bindings of tridentate N2O donor Schiff base metal(II) complexes.

    PubMed

    Kathiresan, Sellamuthu; Anand, Thangavel; Mugesh, Subramanian; Annaraj, Jamespandi

    2015-07-01

    To evaluate the biological preference of synthetic small drugs towards DNA target, new metal based chemotherapeutic agents of Cu(II), Co(II), Ni(II) and Zn(II), 2,4-diiodo-6-((pyridin-2-ylmethylimino)methyl)phenol (L) Schiff base complexes (1, 2, 3 &4) having N,N,O donor system respectively were synthesized and thoroughly characterized. The IR results confirmed the tridentate binding of the ligand with metal centre during complexation and reflects the proposed structure. The density function theory calculations were also used to further investigate the electronic structure and properties of ligand and complexes. The preliminary investigation of herring Sperm (HS-DNA) interaction propensity of complexes 1-4 were carried out in Tris-HCl buffer at pH 7.1 to demonstrate their mode of interactions. The obtained results reveal that these complexes significantly interact with DNA on the grooves, further, this observed mode of interactions was also confirmed by molecular docking evaluations. The complexes 1-4 were also screened for antimicrobial evaluations which demonstrated that their significant activity against various human pathogens. The cleavage studies with pBR322 plasmid DNA revealed higher nuclease activity of 1 as compared to other complexes. PMID:26000741

  17. Metal carbonyl complexes with Schiff bases derived from 2-pyridinecarboxaldehyde: Syntheses, spectral, catalytic activity and antimicrobial activity studies

    NASA Astrophysics Data System (ADS)

    Ali, Omyma A. M.; El-Medani, Samir M.; Ahmed, Doaa A.; Nassar, Doaa A.

    2014-09-01

    Thermal reactions of [M(CO)6], M = Cr, Mo and W with the two Schiff bases: 2-[(pyridin-2-ylmethylidene)amino]-6-aminopyridine (L1) and 2-[(pyridin-2-ylmethylidene)amino]phenol (HL2) were investigated. Three complexes with molecular formulas [Cr(L1)3], 1, [MoO2(L1)2], 2 and [WO2(L1)2], 3 were isolated from the reactions with L1. The corresponding reactions with HL2 produced the complexes [Cr(HL2)2], 4, [Mo2(CO)4O2(HL2)2], 5 and [W(CO)4(HL2)], 6. All complexes were characterized by elemental analysis, infrared, mass and 1H NMR spectroscopy. The molar conductivities of the complexes in DMF indicated nonelectrolytic behavior. The prepared ligands and their complexes exhibited intraligand (?-?*) fluorescence and can potentially serve as photoactive materials. The catalytic activity of the complexes towards to hydrogen peroxide decomposition reaction was investigated. Both the ligands and their complexes have been screened for antibacterial activities.

  18. Emissive bis-salicylaldiminato Schiff base ligands and their zinc(II) complexes: Synthesis, photophysical properties, mesomorphism and DFT studies

    NASA Astrophysics Data System (ADS)

    Paul, Manoj Kr.; Dilipkumar Singh, Y.; Bedamani Singh, N.; Sarkar, Utpal

    2015-02-01

    Bis-salicylaldiminato Schiff base ligands and their Zn(II) complexes derived from 2,3-Diaminomaleonitrile (DAMN) were synthesized. Their molecular structures, photophysical properties and mesogenic behaviors were investigated. The ligands and their Zn(II) complexes were characterized by using elemental analysis, FT-IR, 1H NMR and molar conductivity measurements. Photophysical properties of ligands and their Zn(II) complexes were investigated in different polar solvents by using UV-visible and fluorescence spectroscopic studies. Ligands emit green light whereas complexes emit orange light upon irradiation with UV-visible light. The liquid crystalline phases of ligands and their Zn(II) complexes were characterized by polarizing optical microscopy and differential scanning calorimetry. The ligand having longer 4-n-octadecyloxy chain (n = 18) displays columnar phase whereas the lower homologues (n = 16, 12) did not show mesophase. The Zn(II) complexes having 4-n-octadecyloxy end chain display smectic B like phase whereas other lower homologues are non mesogenic in nature. The thermal stability of the compounds were studied by using thermo gravimetric analysis. The density functional theory was carried out to obtain the stable molecular conformation, dipole moment, molecular orbitals and polarizability of the ligands and their Zn(II) complexes.

  19. Synthesis, antimicrobial, DNA-binding and photonuclease studies of Cobalt(III) and Nickel(II) Schiff base complexes

    NASA Astrophysics Data System (ADS)

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

    2013-03-01

    New metal complexes of the type [M(nih)(L)](PF6)n·xH2O and [M(nih)2](PF6)·xH2O (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 1H 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 Kb value of 4.9 × 104 M-1 for (3), 4.2 × 104 M-1 for (4), presumably via an intercalation mechanism compared to cobalt(III) complex with Kb value of 4.6 × 104 M-1 (1) and 4.1 × 104 M-1 (2). The DNA Photoclevage experiment shows that, the complexes act as effective DNA cleavage agent.

  20. Rod shaped oxovanadium(IV) Schiff base complexes: Synthesis, mesomorphism and influence of flexible alkoxy chain lengths

    NASA Astrophysics Data System (ADS)

    Gupta, Bishop Dev; Datta, Chitraniva; Das, Gobinda; Bhattacharjee, Chira R.

    2014-06-01

    A series of oxovanadium(IV) complexes of bidentate [N,O] donor Schiff-base ligands of the type [VO(L)2], [L = N-(4-n-alkoxysalicylaldimine)-4?-octadecyloxyaniline, n = 8, 10, 12, 14, 16 and 18] have been synthesized. The compounds were characterized by elemental analyses, Fourier transform infrared spectroscopy (FTIR), 1H, 13C nuclear magnetic resonance (NMR), ultraviolet-visible spectroscopy (UV-Vis), and fast atom bombardment (FAB) mass spectrometry. The mesomorphic behavior of the compounds was studied by polarized optical microscopy (POM) and differential scanning calorimetry (DSC). The ligands and complexes are all thermally stable exhibiting smectic mesomorphism. The ligands 8-OR to16-OR show SmC phase at ?113-118 °C and an unidentified SmX phase reminiscent of soft crystal at ?77-91 °C whereas the complexes all showed SmA phases. Interestingly the complexes with C10 and C12 alkoxy chain length exhibited additionally SmC phases also. The melting points of the ligands linearly increases whereas mesophase to isotropic transition temperature decreases as a function of increasing carbon chain length of alkoxy arm while no trend was apparently noticeable for the complexes.

  1. New ruthenium(II) carbonyl complexes bearing disulfide Schiff base ligands and their applications as catalyst for some organic transformations

    NASA Astrophysics Data System (ADS)

    Prakash, Govindan; Viswanathamurthi, Periasamy

    2014-08-01

    Schiff base disulfide ligands (H2L1-6) were synthesized from the condensation of cystamine with salicylaldehyde(H2L1), 5-chlorosalicylaldehyde(H2L2), o-vanillin(H2L3), 2-hydroxyacetophenone(H2L4), 3-methyl-2-hydroxyacetophenone(H2L5), and 2-hydroxy-1-naphthaldehyde(H2L6). H2L1-6 reacts with the ruthenium precursor complex [RuHCl(CO)(PPh3)3] in benzene giving rise to six new ruthenium(II) complexes of general formula [Ru(CO)L1-6]. Characterization of the new complexes was carried out by using elemental and spectral (IR, UV-Vis, NMR (1H and 13C) and Mass) techniques. An octahedral geometry was assigned for all the complexes based on the spectral data obtained. The catalytic efficiency of the new complexes in aldehyde to amide conversion in the presence of NaHCO3, N-alkylation of aniline in the presence of t-BuOK, and transfer hydrogenation of ketones in the presence of iPrOH/KOH reactions were studied. Furthermore, the effect of solvents and catalyst/substrate ratio on the catalytic aldehyde to amide conversion were also discussed.

  2. Axial ligand exchange of N-heterocyclic cobalt(III) Schiff base complexes: molecular structure and NMR solution dynamics.

    PubMed

    Manus, Lisa M; Holbrook, Robert J; Atesin, Tulay A; Heffern, Marie C; Harney, Allison S; Eckermann, Amanda L; Meade, Thomas J

    2013-01-18

    The kinetic and thermodynamic ligand exchange dynamics are important considerations in the rational design of metal-based therapeutics and therefore, require detailed investigation. Co(III) Schiff base complex derivatives of bis(acetylacetone)ethylenediimine [acacen] have been found to be potent enzyme and transcription factor inhibitors. These complexes undergo solution exchange of labile axial ligands. Upon dissociation, Co(III) irreversibly interacts with specific histidine residues of a protein, and consequently alters structure and causes inhibition. To guide the rational design of next generation agents, understanding the mechanism and dynamics of the ligand exchange process is essential. To investigate the lability, pH stability, and axial ligand exchange of these complexes in the absence of proteins, the pD- and temperature-dependent axial ligand substitution dynamics of a series of N-heterocyclic [Co(acacen)(X)(2)](+) complexes [where X = 2-methylimidazole (2MeIm), 4-methylimidazole (4MeIm), ammine (NH(3)), N-methylimidazole (NMeIm), and pyridine (Py)] were characterized by NMR spectroscopy. The pD stability was shown to be closely related to the nature of the axial ligand with the following trend toward aquation: 2MeIm > NH(3) ? 4MeIm > Py > Im > NMeIm. Reaction of each [Co(III)(acacen)(X)(2)](+) derivative with 4MeIm showed formation of a mixed ligand Co(III) intermediate via a dissociative ligand exchange mechanism. The stability of the mixed ligand adduct was directly correlated to the pD-dependent stability of the starting Co(III) Schiff base with respect to [Co(acacen)(4MeIm)(2)](+). Crystal structure analysis of the [Co(acacen)(X)(2)](+) derivatives confirmed the trends in stability observed by NMR spectroscopy. Bond distances between the Co(III) and the axial nitrogen atoms were longest in the 2MeIm derivative as a result of distortion in the planar tetradentate ligand, and this was directly correlated to axial ligand lability and propensity toward exchange. PMID:23282130

  3. Spectral, electrochemical, thermal, DNA binding ability, antioxidant and antibacterial studies of novel Ru(III) Schiff base complexes.

    PubMed

    Abdel Aziz, Ayman A; Elbadawy, Hemmat A

    2014-04-24

    Four new air stable low spin Ru(III) complexes of the type [Ru(L(1-4))(H2O)2]Cl have been synthesized, where L=dianion of the tetradentate Schiff base ligands namely N,N'bis(salicylaldehyde)4,5-dimethy-l,2-phenylendiammine (L(1)H2), N,N'bis(salicylaldehyde)4,5-dichloro 1,2-phenylendiammine (L(2)H2), N,N'bis(o-vanillin)4,5-dimethy-1,2-phenylendiammine (L(3)H2) and N,N'bis(o-vanillin)4,5-dichloro-1,2-phenylendiammine (L(4)H2). The complexes have been fully characterized by elemental analysis, infrared spectroscopy, electronic spectroscopy, magnetic susceptibility and electron spin resonance spectroscopy. Elemental analyses and spectroscopic data have been showed that, the stoichiometries of complexes were 1:1 with an octahedral geometry for all the complexes. Thermal analysis measurements indicated that the complexes have good thermal stability. The redox behavior of the complexes has been investigated by the cyclic voltammetric technique. The interaction of these complexes with calf thymus DNA (CT-DNA) was explored by different techniques which revealed that the complexes could bind to CT-DNA through an intercalative mode. Furthermore, the antioxidant activity of the Ru(III) complexes against superoxide and hydroxyl radicals was evaluated by using spectrophotometer methods in vitro. The experiments on antioxidant activity show that the complexes were found to possess potent antioxidant activity. Additionally, as a potential application the antibacterial activity of the complexes was assessed by testing their effect on the growth of various strains of bacteria. PMID:24508879

  4. Synthesis, characterization and biological activity of some platinum(II) complexes with Schiff bases derived from salicylaldehyde, 2-furaldehyde and phenylenediamine.

    PubMed

    Gaballa, Akmal S; Asker, Mohsen S; Barakat, Atiat S; Teleb, Said M

    2007-05-01

    Four platinum(II) complexes of Schiff bases derived from salicylaldehyde and 2-furaldehyde with o- and p-phenylenediamine were reported and characterized based on their elemental analyses, IR and UV-vis spectroscopy and thermal analyses (TGA). The complexes were found to have the general formula [Pt(L)(H(2)O)(2)]Cl(2) x nH(2)O (where n=0 for complexes 1, 3, 4; n=1 for complex 2. The data obtained show that Schiff bases were interacted with Pt(II) ions in the neutral form as a bidentate ligand and the oxygens rather than the nitrogens are the most probable coordination sites. Square planar geometrical structure with two coordinated water molecules were proposed for all complexes The free ligands, and their metal complexes were screened for their antimicrobial activities against the following bacterial species: E. coli, B. subtilis, P. aereuguinosa, S. aureus; fungus A. niger, A. fluves; and the yeasts C. albican, S. cervisiea. The activity data show that the platinum(II) complexes are more potent antimicrobials than the parent Schiff base ligands against one or more microorganisms. PMID:16942911

  5. Design, spectral characterization, DFT and biological studies of transition metal complexes of Schiff base derived from 2-aminobenzamide, pyrrole and furan aldehyde.

    PubMed

    Tyagi, Prateek; Chandra, Sulekh; Saraswat, B S; Sharma, Deepansh

    2015-05-15

    A series of two biologically active Schiff base ligands L(1), L(2) have been synthesized in equimolar reaction of 2-aminobenzamide with pyrrol-2-carboxaldehyde and furan-2-carboxaldehyde. The synthesized Schiff bases were used for complexation with different metal ions like Co(II), Ni(II) and Cu(II) by using a molar ratio of ligand: metal as 2:1. The characterization of newly formed complexes was done by (1)H NMR, UV-Vis, TGA, IR, mass spectrophotometry, EPR and molar conductivity studies. The thermal studies suggested that the complexes are more stable as compared to ligand. In DFT studies the geometries of Schiff bases and metal complexes were fully optimized with respect to the energy using the 6-31+g(d,p) basis set. On the basis of the spectral studies an octahedral geometry has been assigned for Co(II) and Ni(II) complexes and distorted octahedral geometry for Cu(II) complexes. All the synthesized compounds, were studied for their in vitro antimicrobial activities, against four bacterial strains and two fungal strains by using serial dilution method. The data also revealed that the metal complexes showed better activity than the ligands due to chelation/coordination. PMID:25706679

  6. Vanadyl tetradentate Schiff base complexes as catalyst for C–H bond activation of olefins with tert-butylhydroperoxide: Synthesis, characterization and structure

    Microsoft Academic Search

    Saeed Rayati; Niloofar Torabi; Akbar Ghaemi; Sajjad Mohebbi; Andrzej Wojtczak; Anna Kozakiewicz

    2008-01-01

    Three N2O2 tetradentate Schiff base ligands (H2L1–3) were prepared by reaction of 1,2-propylenediamine and appropriate aldehyde and ketone and characterized by FT-IR, 1H and 13C NMR. The vanadyl complexes were synthesized by treating an ethanolic solution of the appropriate ligand and one equivalent of VO(acac)2 to yield VOL1–3. These oxovanadium (IV) complexes were characterized on the basis of their FT-IR,

  7. Synthesis, Characterization, Antimicrobial, DNA Cleavage, and In Vitro Cytotoxic Studies of Some Metal Complexes of Schiff Base Ligand Derived from Thiazole and Quinoline Moiety

    PubMed Central

    Yernale, Nagesh Gunvanthrao; Bennikallu Hire Mathada, Mruthyunjayaswamy

    2014-01-01

    A novel Schiff base ligand N-(4-phenylthiazol-2yl)-2-((2-thiaxo-1,2-dihydroquinolin-3-yl)methylene)hydrazinecarboxamide (L) obtained by the condensation of N-(4-phenylthiazol-2-yl)hydrazinecarboxamide with 2-thioxo-1,2-dihydroquinoline-3-carbaldehyde and its newly synthesized Cu(II), Co(II), Ni(II), and Zn(II) complexes have been characterized by elemental analysis and various spectral studies like FT-IR, 1H NMR, ESI mass, UV-Visible, ESR, TGA/DTA, and powder X-ray diffraction studies. The Schiff base ligand (L) behaves as tridentate ONS donor and forms the complexes of type [ML(Cl)2] with square pyramidal geometry. The Schiff base ligand (L) and its metal complexes have been screened in vitro for their antibacterial and antifungal activities by minimum inhibitory concentration (MIC) method. The DNA cleavage activity of ligand and its metal complexes were studied using plasmid DNA pBR322 as a target molecule by gel electrophoresis method. The brine shrimp bioassay was also carried out to study the in vitro cytotoxicity properties for the ligand and its metal complexes against Artemia salina. The results showed that the biological activities of the ligand were found to be increased on complexation. PMID:24729778

  8. Structure and aggregation properties of a Schiff-base zinc(ii) complex derived from cis-1,2-diaminocyclohexane.

    PubMed

    Consiglio, Giuseppe; Oliveri, Ivan Pietro; Punzo, Francesco; Thompson, Amber L; Di Bella, Santo; Failla, Salvatore

    2015-07-14

    This contribution explores the effect of the bridging diamine upon the aggregation properties of a Zn(II) Schiff-base complex, , both in the solid state and in solution. The X-ray structure of , resulting from the harvest of good quality crystals using chloroform and diethyl ether as solvents, shows the presence of a densely packed dimer in the solid state which pentacoordinates two Zn atoms involved in a ?-phenoxo bridge. Detailed studies in solution, through (1)H NMR, DOSY NMR, and optical spectroscopic investigations, indicate the typical aggregation/deaggregation behaviour on switching from non-coordinating to coordinating solvents, in relation to the Lewis acidic character of such Zn(II) complexes. Thus, while in DMSO-d6 both (1)H NMR and DOSY studies suggest the existence of monomeric species, in chloroform solution experimental data support the existence of aggregates. However, unlike our previous studies, (1)H NMR data in chloroform solution indicate the existence of an asymmetric dimer, as observed in the X-ray crystal structure. This further evidences a very rigid backbone of the dimeric aggregate and can be related to the defined stereochemistry of the chelate cis-1,2-diaminocyclohexane bridge. PMID:26103462

  9. Synthesis of 1,3,5-tris(4-(4-nitrophenyliminomethyl)phenoxymethyl)benzene as a new Schiff base and its complexation properties with the (salen and salophen)-bridged Fe\\/Cr(III)

    Microsoft Academic Search

    Ozcan Kocyigit; Ersin Guler

    2010-01-01

    In the present study, we discussed to synthesis of a new Schiff base with nitro groups and its complexation properties with\\u000a Fe\\/Cr(III) salen\\/salophen capped complexes. For this, 1,3,5-tris (formylphenoxymethyl)benzene (1, TRIPOD) involving aldehyde groups was converted to the Schiff base derivative (2, TNPIM-TRIPOD) using 4-nitroaniline. The synthesized compound 2 were reacted with four new trinuclear Fe(III) and Cr(III) complexes involving

  10. Vanadium(V) complex with Schiff-base ligand containing a flexible amino side chain: Synthesis, structure and reactivity.

    PubMed

    Nica, Simona; Rudolph, Manfred; Lippold, Ines; Buchholz, Axel; Görls, Helmar; Plass, Winfried

    2015-06-01

    The Schiff-base ligand (H2salhyhNH3)Cl (1) derived from salicylaldehyde and 6-aminohexanoic acid hydrazide hydrochloride reacts with ammonium metavanadate in methanol solution to yield the dioxidovanadium(V) complex [VO2(salhyhNH3)] (2). The utilized hydrazone ligand contains a flexible and protonated amino side chain. Crystallization from methanol affords complex 2 in the monoclinic space group P21/n, whereas crystallization from a methanol/water mixture 1:1 yields crystals, containing a water molecule of crystallization per two formula units (2?1/2H2O), in the orthorhombic space group Pbcn. In both cases the protonated amino group compensates the negative charge on the dioxidovanadium moiety and is involved in an extensive hydrogen bonding network particularly including the oxido groups from neighboring vanadium complexes. The reactivity of complex 2 toward protonation in aqueous solution has been investigated by spectrophotometric titrations and is characterized by two subsequent protonation steps at the hydrazide nitrogen atom of the ligand system and an oxido group leading to the formation of an oxidohydroxidovanadium(V) species with corresponding pKa values of 3.2 and 2.9, respectively. With larger excess of acid the oxidohydroxidovanadium(V) species starts to form the corresponding anhydride. The formation of the anhydride is strongly favored in the presence of methanol. The reaction of complex 2 with hydrogen peroxide in methanol solution leads to the formation of an oxidoperoxidovanadium(V) species, whereas in aqueous solution the addition of one equivalent of acid is required. Complex 2 catalyzes the oxidation of methylphenylsulfane to the corresponding sulfoxide in methanol/dichloromethane mixture using hydrogen peroxide as oxidant at room temperature. PMID:25747149

  11. Synthesis, spectral characterization and DNA binding of Schiff-base metal complexes derived from 2-amino-3-hydroxyprobanoic acid and acetylacetone

    NASA Astrophysics Data System (ADS)

    Hosny, Nasser Mohammed; Hussien, Mostafa A.; Radwan, Fatima M.; Nawar, Nagwa

    2014-11-01

    Four new metal complexes derived from the reaction of Cu(II), Co(II), Ni(II) and Zn(II) acetates with the Schiff-base ligand (H3L) resulted from the condensation of the amino acid 2-amino-3-hydroxyprobanoic acid (serine) and acetylacetone have been synthesized and characterized by, elemental analyses, ES-MS, IR, UV-Vis., 1H NMR, 13C NMR, ESR, thermal analyses (TGA and DTG) and magnetic measurements. The results showed that the Schiff-base ligand acts as bi-negative tridentate through the azomethine nitrogen, the deprotonated carboxylate oxygen and the enolic carbonyl oxygen. The optical band gaps measurements indicated the semi-conducting nature of these complexes. Molecular docking was used to predict the binding between the Schiff base ligand with the receptor of prostate cancer mutant H874Y. The interactions between the Cu(II) complex and calf thymus DNA (CT-DNA) have been studied by UV spectra. The results confirm that the Cu(II) complex binds to CT-DNA in an intercalative mode.

  12. Synthesis, spectral characterization and DNA binding of Schiff-base metal complexes derived from 2-amino-3-hydroxyprobanoic acid and acetylacetone.

    PubMed

    Hosny, Nasser Mohammed; Hussien, Mostafa A; Radwan, Fatima M; Nawar, Nagwa

    2014-11-11

    Four new metal complexes derived from the reaction of Cu(II), Co(II), Ni(II) and Zn(II) acetates with the Schiff-base ligand (H3L) resulted from the condensation of the amino acid 2-amino-3-hydroxyprobanoic acid (serine) and acetylacetone have been synthesized and characterized by, elemental analyses, ES-MS, IR, UV-Vis., 1H NMR, 13C NMR, ESR, thermal analyses (TGA and DTG) and magnetic measurements. The results showed that the Schiff-base ligand acts as bi-negative tridentate through the azomethine nitrogen, the deprotonated carboxylate oxygen and the enolic carbonyl oxygen. The optical band gaps measurements indicated the semi-conducting nature of these complexes. Molecular docking was used to predict the binding between the Schiff base ligand with the receptor of prostate cancer mutant H874Y. The interactions between the Cu(II) complex and calf thymus DNA (CT-DNA) have been studied by UV spectra. The results confirm that the Cu(II) complex binds to CT-DNA in an intercalative mode. PMID:24858353

  13. Cr(III), Fe(III) and Co(III) complexes of tetradentate (ONNO) Schiff base ligands: Synthesis, characterization, properties and biological activity

    NASA Astrophysics Data System (ADS)

    Keskio?lu, Eren; Gündüzalp, Ayla Balaban; Çete, Servet; Hamurcu, Fatma; Erk, Birgül

    2008-08-01

    A series of metal complexes were synthesized from equimolar amounts of Schiff bases: 1,4-bis[3-(2-hydroxy-1-naphthaldimine)propyl]piperazine (bappnaf) and 1,8-bis[3-(2-hydroxy-1-naphthaldimine)- p-menthane (damnaf) with metal chlorides. All of synthesized compounds were characterized by elemental analyses, spectral (UV-vis, IR, 1H- 13C NMR, LC-MS) and thermal (TGA-DTA) methods, magnetic and conductance measurements. Schiff base complexes supposed in tetragonal geometry have the general formula [M(bappnaf or damnaf)]Cl· nH 2O, where M = Cr(III), Co(III) and n = 2, 3. But also Fe(III) complexes have octahedral geometry by the coordination of two water molecules and the formula is [Fe(bappnaf or damnaf)(H 2O) 2]Cl. The changes in the selected vibration bands in FT-IR indicate that Schiff bases behave as (ONNO) tetradentate ligands and coordinate to metal ions from two phenolic oxygen atoms and two azomethine nitrogen atoms. Conductance measurements suggest 1:1 electrolytic nature of the metal complexes. The synthesized compounds except bappnaf ligand have the antimicrobial activity against the bacteria: Escherichia coli (ATCC 11230), Yersinia enterocolitica (ATCC 1501), Bacillus magaterium (RSKK 5117), Bacillus subtilis (RSKK 244), Bacillus cereus (RSKK 863) and the fungi: Candida albicans (ATCC 10239). These results have been considerably interest in piperazine derivatives due to their significant applications in antimicrobial studies.

  14. SYNTHESIS, CHARACTERIZATION, ANTIMICROBIAL AND CYTOTOXIC STUDIES ON SOME NOVEL TRANSITION METAL COMPLEXES OF SCHIFF BASE LIGAND DERIVED FROM SULFADIAZINE WITH MOLECULAR ORBITAL CALCULATIONS

    Microsoft Academic Search

    Badr A. Elsayed; A. A. Elhenawy

    2014-01-01

    Some selected solid complexes of the Schiff base ligand HL derived from Sulfadiazine with Co(II), Ni(II) and Cu(II) ions were synthesized and characterized by Micro-analysis, FTIR, Electronic, Mass, and ESR Spectral Analyses, Magnetic susceptibility and Molar Conductance Measurements. The disappearance of ?(O-H) hydroxyl band of the phenolic and the lowering shift of the stretching frequency of the ?(CH=N) azomethine band

  15. 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/?-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 ?-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 ?-NPD layer.

  16. Studies on the complexing behavior of a potentially tetradentate Schiff-base ligand with some transition metal ions

    Microsoft Academic Search

    M. Sivasankaran Nair; C. Ravi Samuel Raj

    2009-01-01

    The Schiff base furfural-histidine with Co(II), Ni(II), Cu(II), and Zn(II) in solution gives M(AB), M(AB)B, or M(AB)2. The Schiff base is tetradentate in M(AB)2 and M(AB)B and tridentate in M(AB)2; [M(AB)2] · 2H2O (M = Co, Ni and Zn) and [Cu(AB)]NO3 were synthesized and characterized by elemental analysis, molecular weight determination, conductance, IR, UV–Vis, and CV. The electronic spectral measurements

  17. 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

  18. Synthesis and characterization of novel rhenium(V) tetradentate N2O2 Schiff base monomer and dimer complexes.

    PubMed

    Benny, Paul D; Barnes, Charles L; Piekarski, Pamela M; Lydon, John D; Jurisson, Silvia S

    2003-10-01

    Several rhenium(V) oxo complexes with tetradentate N(2)O(2) Schiff base ligands were synthesized and characterized. The general synthetic procedure involved reaction of [NBu(4)][ReOCl(4)] with a tetradentate Schiff base ligand (L(1) = N,N'-ethylenebis(acetylacetoneimine), (acac(2)en) or L(2) = N,N'-propylenebis(acetylacetoneimine) (acac(2)pn)) in ethanol solution to generate complexes of the form trans-ReOX(L) where X = Cl(-), MeO(-), ReO(4)(-), or H(2)O. The product isolated from the reaction was found to be dependent on the reaction conditions, in particular the presence or absence of water and/or base. The mu-oxo-Re(2)O(3)(L)(2) dimers were synthesized and characterized for chemical and structural comparison to the related monomers. Conversion of the monomer to its dimer analogue was followed qualitatively by spectrophotometry. The complexes were characterized by (1)H and (13)C NMR, UV-vis, and IR spectroscopy, elemental analysis, and single crystal X-ray diffraction. The crystallographic data reported for the structures are as follows: trans-[ReO(OH(2))(acac(2)en)]Cl (H(20)C(12)ClN(2)O(4)Re) 1, triclinic (Ponemacr;), a = 7.2888(6) A, b = 9.8299(8) A, c = 10.8195(9) A, alpha = 81.7670(10) degrees, beta = 77.1510(10) degrees, gamma = 87.6200(10) degrees, V = 747.96(11) A(3), Z = 2; trans-[ReO(OReO(3))(acac(2)en)] (H(18)C(12)N(2)O(7)Re(2)) 2, monoclinic (P2(1)/c), a = 7.5547(4) A, b = 8.7409(5) A, c= 25.7794(13) A, beta = 92.7780(10) degrees, V = 1700.34(16) A(3), Z = 4; trans-[ReOCl(acac(2)pn)] (H(20)C(13)N(2)O(3)ClRe) 3, monoclinic (P2(1)/c), a = 8.1628(5) A, b = 13.0699(8) A, c = 28.3902(17) A, beta = 97.5630(10) degrees, V = 3002.5(3) A(3), Z = 8; trans-[ReO(OMe)(acac(2)pn)] (H(23)C(14)N(2)O(4)Re) 4, monoclinic (P2(1)/c), a = 6.7104(8) A, b = 27.844(3) A, c = 8.2292(9) A, beta = 92.197(2) degrees, V = 1536.4(3) A(3), Z = 4; trans-[mu-oxo-Re(2)O(3)(acac(2)en)(2)] (H(36)C(24)N(4)O(7)Re(2)) 5, monoclinic (P2(1)/n), a = 9.0064(5) A, b = 12.2612(7) A, c = 12.3695(7) A, beta = 90.2853(10) degrees, V = 1365.94(13) A(3), Z = 2; and trans-[mu-oxo Re(2)O(3)(acac(2)pn)(2)] (H(40)C(26)N(4)O(7)Re(2)) 6, monoclinic (P2(1)/n), a = 9.1190(5) A, b = 12.2452(7) A, c = 12.8863(8) A, beta = 92.0510(10) degrees, V = 1438.01(14) A(3), Z = 2. PMID:14514329

  19. Synthesis, characterization and oxygen affinity of Mn(II), Co(II) and Ni(II) complexes of diethylenetriamine Schiff bases

    Microsoft Academic Search

    Adel A. Emara; A. M. Ali; E. M. Ragab; A. A. El-Asmy

    2008-01-01

    N,N?-diethyleneamine bis(salicylideneimine); H2DETS and N,N?-diethyleneamine bis(o-hydroxyacetophenoneimine); H2DETHA have been prepared to produce Mn(II), Co(II) and Ni(II) complexes by the addition of the synthesized Schiff bases to the studied ions under nitrogen. H2DETS and H2DETHA are neutral tridentate in the nitrato complexes and binegative pentadentate in the other complexes. A square pyramidal structure was suggested for all complexes based on elemental

  20. Synthesis of novel p-tert-butylcalix[4]arene Schiff bases and their complexes with C60, potential HIV-Protease inhibitors

    NASA Astrophysics Data System (ADS)

    Khadra, Khalid Abu; Mizyed, Shehadeh; Marji, Deeb; Haddad, Salim F.; Ashram, Muhammad; Foudeh, Ayat

    2015-02-01

    Some p-tert-butylcalix[4]arene Schiff base crown ethers were synthesized, characterized using 1H, 13C-NMR, DEPT 135 and Mass spectrometry. Their complexes with C60 were isolated and characterized. The inhibition effect of these complexes on HIVP was studied and found that complexes of 9 and 10 have comparable Ki values to Pepstatine which is known as HIVP inhibitor and used as a control. The synthesis of the ligands, complexes and the inhibition behavior are discussed in this article.

  1. Metal Complexes with Schiff Base Ligands: Pyridoxal and Semicarbazide-Based Derivatives

    Microsoft Academic Search

    Vukadin M. Leovac; Violeta S. Jevtovic; Ljiljana S. Jovanovic; Goran A. Bogdanovic

    2005-01-01

    The most important results of extensive studies (syntheses, spectral, mag- netic, voltammetric and structural characteristics and biological activity) of metal complexes with pyridoxal semi-, thiosemi- and isothiosemicarbazones are reviewed.

  2. Crystal structure and antitumor activity of some rare earth metal complexes with Schiff base

    Microsoft Academic Search

    Zheng-Yin Yang; Ru-Dong Yang; Fa-Shen Li; Kai-Bei Yu

    2000-01-01

    The ligand 1-phenyl-3-methyl-5-hydroxy-4-pyrazolyl phenyl ketone (PMBP) isonicotinoyl hydrazone (H2L) was prepared by condensation of PMBP with isoniazid. Seven complexes of rare earth metals with H2L were synthesized and characterized on the basis of elemental analyses, IR, UV, 1H NMR spectra and thermal analyses. The general formula of the complexes is Ln(HL)3·3.5H2O (where Ln(III)=La, Eu, Gd, Tb, Dy, Ho and Er).

  3. Asymmetric Schiff Base (N 2 O 3 ) Complexes as Ligands Towards Mn(II), Fe(III) and Co(II), Synthesis and Characterization

    Microsoft Academic Search

    Saied M. E. Khalil; Adel. A. Emara

    2002-01-01

    Heterobi- and tri-nuclear complexes [LMM'Cl] and [(LM) 2 M'](M=Ni or Cu and M'=Mn, Fe or Co) have been synthesised. The heteronuclear complexes were prepared by stepwise reactions using two mononuclear Ni(II) and Cu(II) complexes of the general formula [HLM]·1\\/2H 2 O, as ligands towards the metal ions, Mn(II), Fe(III) and Co(II). The asymmetrical pentadentate (N 2 O 3 ) Schiff-base

  4. New tetradentate Schiff bases of 2-amino-3,5-dibromobenzaldehyde with aliphatic diamines and their metal complexes: Synthesis, characterization and thermal stability

    NASA Astrophysics Data System (ADS)

    Mohammadi, Khosro; Azad, Seyyedeh Sedigheh; Amoozegar, Ameneh

    2015-07-01

    The tetradentate Schiff base ligands (L1-L4), were synthesized by reaction between 2-amino-3,5-dibromobenzaldehyde and aliphatic diamines. Then, nickel and oxovanadium(IV) complexes of these ligands were synthesized and characterized by 1H NMR, Mass, IR, UV-Vis spectroscopy and thermogravimetry. The kinetic parameters of oxovanadium(IV) complexes were calculated from thermal studies. According to the results of thermogravimetric data, the thermal stability of oxovanadium(IV) complexes is as follow: VOL2(ClO4)2 >VOL4(ClO4)2 >VOL3(ClO4)2 >VOL1(ClO4)2

  5. Novel tetranuclear Ni(II) Schiff base complex containing Ni4O4 cubane core: Synthesis, X-ray structure, spectra and magnetic properties

    NASA Astrophysics Data System (ADS)

    Jana, Mahendra Sekhar; Priego, José L.; Jiménez-Aparicio, Reyes; Mondal, Tapan Kumar

    2014-12-01

    Novel tetranuclear nickel(II) Schiff base complex having symmetric Ni4O4 cubane-core, [Ni4O2(OAc)2(L)2] (1) has been synthesized. Single crystal of the complex exhibits four nickel atoms in the alternate corner of the cubane and other four sites are occupied by phenolate-O and ?3-O2-. Variable temperature magnetic moment data suggests the Ni centres are weakly antiferromagnetically coupled with J1 = -4.82 cm-1 and J2 = -4.83 cm-1. The electronic spectra, emission properties and life time measurement of ligand, HL and complex 1 have been studied.

  6. Novel tetranuclear Ni(II) Schiff base complex containing Ni4O4 cubane core: synthesis, X-ray structure, spectra and magnetic properties.

    PubMed

    Jana, Mahendra Sekhar; Priego, José L; Jiménez-Aparicio, Reyes; Mondal, Tapan Kumar

    2014-12-10

    Novel tetranuclear nickel(II) Schiff base complex having symmetric Ni4O4 cubane-core, [Ni4O2(OAc)2(L)2] (1) has been synthesized. Single crystal of the complex exhibits four nickel atoms in the alternate corner of the cubane and other four sites are occupied by phenolate-O and ?3-O(2-). Variable temperature magnetic moment data suggests the Ni centres are weakly antiferromagnetically coupled with J1=-4.82cm(-1) and J2=-4.83cm(-1). The electronic spectra, emission properties and life time measurement of ligand, HL and complex 1 have been studied. PMID:24996213

  7. From homogeneously to heterogeneously catalyzed cyclopropanation reactions: New polymeric membranes embedding cobalt chiral schiff base complexes

    Microsoft Academic Search

    Alessandro Caselli; Maria Giovanna Buonomenna; Federico de Baldironi; Luca Laera; Simone Fantauzzi; Fabio Ragaini; Emma Gallo; Giovanni Golemme; Sergio Cenini; Enrico Drioli

    2010-01-01

    In this paper we report the preparation of catalytic polymeric membranes having the complex [(N,N?-bis(3-tert-butyl-5-(heptadecafluorooctyl)salicylidene)-trans-1,2-cyclohexanediamine)Co] embedded into Hyflon AD60X, PES and PSf and their use in the cyclopropanation reaction of olefins with ethyl diazoacetate (EDA). A study of the reaction in the homogeneous phase was also performed. The kinetics of the cyclopropanation reaction is first-order in the diazoacetate and the

  8. Structure, photochemistry and magnetic properties of tetrahydrogenated Schiff base chromium(III) complexes.

    PubMed

    Liu, Bin; Chai, Jie; Feng, SiSi; Yang, BinSheng

    2015-04-01

    Four mononuclear chromium(III) complexes [Cr(L(1))(en)]Br0.3Cl0.7 (1), [Cr(L(1))(pr)]Cl (2), [Cr(L(2))(en)]ClO4 (3), [Cr(L(2))(pr)]Cl (4) along with one dinuclear ?-methoxo [Cr(?-OMe)(L1)]2 (5) were synthesized (en=1,2-ethanediamine, pr=1,3-diaminopropane H2L(1)=Tetrahydrosalen=H2[H4]salen=N,N'-bis(2-hydroxybenzyl)-1,2-ethanediamine, H2L(2)=Tetrahydrosalpr=H2[H4]salpr=N,N'-bis(2-hydroxybenzyl)-1,3-diaminopropane). The competitive reactions in the presence of EDTA were carried out and the first-order rate constants k(1)=(5.2±0.2)×10(-3) h(-1)complex 5 exhibits a strong antiferromagnetic coupling with the J=-10.8 cm(-1). PMID:25637815

  9. Spectroscopic studies and biological evaluation of some transition metal complexes of Schiff-base ligands derived from 5-arylazo-salicylaldehyde and thiosemicarbazide

    Microsoft Academic Search

    Moamen S. Refat; Ibrahim M. El-Deen; Zeinab M. Anwer; Samir El-Ghol

    2009-01-01

    Synthesis and spectroscopic characterization of Schiff-base complexes of Cu(II), Ni(II), and Mn(II) resulting from condensation of salicylaldehyde derivatives with thiosemicarbazide [PHBT = 1-(5-(2-phenyldiazenyl)-2-hydroxybenzylidene)thiosemicarbazide, CHBT = 1-(5-(2-(2-chlorophenyl)diazenyl)-2-hydroxybenzylidene)thiosemicarbazide, and MHBT = 1-(5-(2-p-tolyldiazenyl)-2-hydroxybenzylidene)thiosemicarbazide] are discussed. The solid complexes were confirmed by elemental analysis (CHN), molar conductance, and mass spectra. Important infrared (IR) spectral bands corresponding to the active groups in the three ligands,

  10. Synthesis and spectroscopic studies of novel transition metal complexes with schiff base synthesized from 1,4-bis-( o -aminophenoxy)butane and salicyldehyde

    Microsoft Academic Search

    Hamdi Temel; Salih Ilhan

    2009-01-01

    The new Co(II), Cu(II), Ni(II) and Zn(II) complexes of potentially N2O2 Schiff base ligand [N,N’-bis(salicyldehydene)-1,4-bis-(o-aminophenoxy)butane] (H2L) prepared from 1,4-bis-(o-aminophenoxy)butane and salicyldehyde in DMF. Microanalytical data, elemental analysis, magnetic measurements, lH NMR, 13C NMR, UV-visible and IR spectra as well as conductance measurements were used to confirm the structures. In all complexes,\\u000a H2L behaves as a tetradentate.

  11. Synthesis, spectral, redox and antimicrobial activities of Schiff base complexes derived from 1-phenyl-2,3-dimethyl-4-aminopyrazol-5-one and acetoacetanilide

    Microsoft Academic Search

    Natarajan Raman; Antonysamy Kulandaisamy; Arunachalam Shunmugasundaram; Kadarkaraithangam Jeyasubramanian

    2001-01-01

    Novel terdentate neutral complexes of CuII, NiII, CoII, MnII, ZnII, CdII, HgII, VOII, ZrOII and UO2II have been prepared using a Schiff base derived from 1-phenyl-2,3-dimethyl-4-aminopyrazol-5-one (4-aminoantipyrine) and acetoacetanilide. The structural features of the chelates have been confirmed by microanalytical data, i.r., u.v.–vis., 1H-n.m.r., e.s.r. and mass spectral techniques. Electronic absorption and i.r. spectra of the complexes indicate an octahedral

  12. Spectroscopic studies of bimetallic complexes derived from tridentate or tetradentate Schiff bases of some di- and tri-valent transition metals

    Microsoft Academic Search

    Adel A. A. Emara; Azza A. A. Abou-Hussen

    2006-01-01

    Two series of new binuclear complexes with Schiff base ligands, H4La or H2Lb, derived from the reaction of 4,6-diacetylresorcinol and ethylenediamine, in the molar ratio 1:1 and 1:2 have been prepared, respectively. The two ligands react with Co(II), Ni(II), Cu(II), Zn(II), Cd(II), Cr(III) and Fe(III)-nitrates to get binuclear complexes. The ligands were characterized by elemental analysis, IR, UV–vis, 1H NMR

  13. Metal-pyrazolyl diazine interaction: Synthesis, structure and electrochemistry of binuclear transition metal(II) complexes derived from an `end-off' compartmental Schiff base ligand

    NASA Astrophysics Data System (ADS)

    Budagumpi, Srinivasa; Revankar, Vidyanand K.

    2010-09-01

    Pyrazolyl diazine (?-NN) bridged late first row transition metal(II) complexes have been prepared by the interaction of metal(II) chlorides with an 'end-off' compartmental Schiff base ligand. The ligand system has a strong diazine bridging component and obtained as a condensation product between 1 H-pyrazole-3,5-dicarbohydrazide and 3-acetylcoumarin in absolute ethanol. All synthesized compounds are characterized on the basis of various spectral and analytical techniques. Complexes are found to be non-electrolytes and monomeric in nature. The magnetic exchange interactions are very weak because of the more electronegative exogenous chloride, though diazine bridging group bring metal centers in a close proximity.

  14. Asymmetric Oxidation of Sulfides Catalyzed by Vanadium(IV) Complexes of Dibromo- and Diiodo-Functionalized Chiral Schiff Bases

    Microsoft Academic Search

    Aiping GAO; Mei WANG; Dongping WANG; Lu ZHANG; Haibin LIU; Wei TIAN; Licheng SUN

    2006-01-01

    The catalyst system of VO(acac)2 and Schiff base ligands derived from 3,5-dibromo- or 3,5-diiodosalicylaldehyde and inexpensive chiral amino alcohols was prepared. This catalyst has good yields and moderate-to-high enantioselectivity for the asymmetric oxidation of aryl methyl sulfides at room temperature when 1% catalyst (VO(acac)2\\/ligand molar ratio of 1:2) and H2O2 oxidant were used. The ligands derived from (S)-valinol exhibit considerably

  15. Synthesis, Characterization, Antimicrobial, DNA Cleavage, and Antioxidant Studies of Some Metal Complexes Derived from Schiff Base Containing Indole and Quinoline Moieties

    PubMed Central

    Karekal, Mahendra Raj; Biradar, Vivekanand; Bennikallu Hire Mathada, Mruthyunjayaswamy

    2013-01-01

    A new Schiff base of 5-chloro-3-phenyl-1H-indole-2-carboxyhydrazide and 3-formyl-2-hydroxy-1H-quinoline (HL), and its Cu(II), Co(II), Ni(II), Zn(II), Cd(II), and Hg(II) complexes have been synthesized and characterized in the light of microanalytical, IR, H1 NMR, UV-Vis, FAB-mass, ESR, XRD, and TGA spectral studies. The magnetic susceptibility measurements and low conductivity data provide evidence for monomeric and neutral nature of the complexes. On the basis of spectral studies and analytical data, it is evident that the Schiff base acts as tridentate ligand. The Cu(II), Co(II), and Ni(II) complexes were octahedral, whereas Zn(II), Cd(II), and Hg(II) complexes were tetrahedral in nature. The redox behavior of the Cu(II) complex was investigated by electrochemical method using cyclic voltammetry. In order to evaluate the effect of metal ions upon chelation, both the ligand and its metal complexes were screened for their antibacterial and antifungal activities by minimum inhibitory concentration (MIC) method. The DNA cleavage experiment performed using agarose gel electrophoresis method showed the cleavage of DNA by all the metal complexes. The free radical scavenging activity of newly synthesized compounds has been determined at a different concentration range by means of their interaction with the stable free radical 1,1-diphenyl-2-picrylhydrazyl (DPPH). PMID:24194692

  16. Synthesis of electron-rich uranium(IV) complexes supported by tridentate Schiff base ligands and their multi-electron redox chemistry.

    PubMed

    Camp, Clément; Andrez, Julie; Pécaut, Jacques; Mazzanti, Marinella

    2013-06-17

    The synthesis, structure, and reactivity of a new complex of U(IV) with the tridentate Schiff base ligand Menaphtquinolen are reported. The reduction of the bis-ligand complexes [UX2((Me)naphtquinolen)2] (X = Cl, (1-Cl) ; I (1-I)) with potassium metal affords the U(IV) complex of the new tetranionic hexadentate ligand ?-bis-(Me)naphtquinolen formed through the intramolecular reductive coupling of the imino groups of each (Me)naphtquinolen unit. The solid state structure of the [U(?-bis-(Me)naphtquinolen)]2 dimer 2 isolated from toluene confirms the presence of a U(IV) complex of the reduced ligand. Reactivity studies with molecular oxygen and 9,10-phenanthrenequinone show that complex 2 can act as a multielectron reducing agent releasing two electrons through the cleavage of the C-C bond to restore the original imino function of the ligand. In the resulting U(IV) and U(VI) complexes [U(9,10-phenanthrenediol)((Me)naphtquinolen)2], 3, and [UO2((Me)naphtquinolen)2], 4, the restored tridentate Schiff base allows for the coordination of the reduced substrate to the metal. Electrochemical studies of complex 2 show the presence of irreversible ligand centered reduction processes and of a reversible U(IV)/U(III) couple. PMID:23734761

  17. Synthesis, characterization, antimicrobial, DNA cleavage, and antioxidant studies of some metal complexes derived from schiff base containing indole and quinoline moieties.

    PubMed

    Karekal, Mahendra Raj; Biradar, Vivekanand; Bennikallu Hire Mathada, Mruthyunjayaswamy

    2013-01-01

    A new Schiff base of 5-chloro-3-phenyl-1H-indole-2-carboxyhydrazide and 3-formyl-2-hydroxy-1H-quinoline (HL), and its Cu(II), Co(II), Ni(II), Zn(II), Cd(II), and Hg(II) complexes have been synthesized and characterized in the light of microanalytical, IR, H1 NMR, UV-Vis, FAB-mass, ESR, XRD, and TGA spectral studies. The magnetic susceptibility measurements and low conductivity data provide evidence for monomeric and neutral nature of the complexes. On the basis of spectral studies and analytical data, it is evident that the Schiff base acts as tridentate ligand. The Cu(II), Co(II), and Ni(II) complexes were octahedral, whereas Zn(II), Cd(II), and Hg(II) complexes were tetrahedral in nature. The redox behavior of the Cu(II) complex was investigated by electrochemical method using cyclic voltammetry. In order to evaluate the effect of metal ions upon chelation, both the ligand and its metal complexes were screened for their antibacterial and antifungal activities by minimum inhibitory concentration (MIC) method. The DNA cleavage experiment performed using agarose gel electrophoresis method showed the cleavage of DNA by all the metal complexes. The free radical scavenging activity of newly synthesized compounds has been determined at a different concentration range by means of their interaction with the stable free radical 1,1-diphenyl-2-picrylhydrazyl (DPPH). PMID:24194692

  18. Synthesis of a series of new platinum organometallic complexes derived from bidentate Schiff-base ligands and their catalytic activity in the hydrosilylation and dehydrosilylation of styrene.

    PubMed

    Lachachi, M Belhadj; Benabdallah, Tayeb; Aguiar, Pedro M; Youcef, M Hadj; Whitwood, Adrian C; Lynam, Jason M

    2015-07-14

    The synthesis and properties of a novel class of platinum complexes containing Schiff bases as O,N-bidentate ligands is described as are the solution and solid state properties of the uncomplexed ligands. The platinum complexes were prepared from [PtBr2(COD)] (COD = 1,5-cyclooctadiene) and N-(2-hydroxy-1-naphthalidene)aniline derivatives in the presence of base (NaOBu(t)). Instead of a substitution reaction to afford cationic species, the addition of the Schiff base ligands results in both the formal loss of two equivalents of bromide and addition of hydroxide to the COD ligand of the complexes. It is proposed that this reaction proceeds through a cationic platinum complex [Pt(N-O)(COD)]Br which then undergoes addition of water and loss of HBr. An example of a dinuclear platinum complex in which two cyclo-octene ligands are bridged by an ether linkage is also reported. The platinum complexes were evaluated as catalysts for the hydrogenative and dehydrogenative silylation of styrene, the resulting behaviour is substituent, time and temperature dependent. PMID:26061657

  19. DNA interaction, antimicrobial, electrochemical and spectroscopic studies of metal(II) complexes with tridentate heterocyclic Schiff base derived from 2?-methylacetoacetanilide

    NASA Astrophysics Data System (ADS)

    Raman, Natarajan; Pothiraj, Krishnan; Baskaran, Thanasekaran

    2011-08-01

    A new Schiff base ligand (HL) was synthesized by the condensation reaction between 2'-methyleacetoacetanilide and 2-amino-3-hydroxypyridine. Its Co(II), Ni(II), Cu(II) and Zn(II) complexes were prepared by the interaction of the ligand with metal(II) chloride. They were characterized by elemental analysis, IR, 1H NMR, EPR, UV-Vis, magnetic susceptibility measurements, conductivity measurements and FAB-mass spectra. The interaction of the complexes with calf thymus DNA (CT-DNA) has been investigated by UV absorption, viscosity and cyclic voltammetry methods, and the mode of CT-DNA binding to the complexes has been explored. Furthermore, the DNA cleavage activity by the complexes was performed. It was found to be oxidative hydroxyl radical cleavage in the presence of 3-mercaptopropionic acid (MPA). The Schiff base and its complexes have been screened for their antibacterial ( Staphylococcus aureus, Escherichia coli, Bacillus subtilis and Pseudomonas aeruginosa) and antifungal ( Aspergillus niger, Rhizopus stolonifer, Rhizoctonia bataicola and Candida albicans) activities and the data reveal that the complexes have higher activity than the free ligand.

  20. Synthesis, crystal structure and interaction of L-valine Schiff base divanadium(V) complex containing a V2O3 core with DNA and BSA.

    PubMed

    Guo, Qiong; Li, Lianzhi; Dong, Jianfang; Liu, Hongyan; Xu, Tao; Li, Jinghong

    2013-04-01

    A divanadium(V) complex, [V2O3(o-van-val)2] (o-van-val=Schiff base derived from o-vanillin and L-valine), has been synthesized and structurally characterized. The crystal structure shows that both of the vanadium centers in the complex have a distorted octahedral coordination environment composed of tridentate Schiff base ligand. A V2O3 core in molecular structure adopts intermediate between cis and trans configuration with the O1V1?V1AO1A torsion angle 115.22 (28)° and the V1?V1A distance 3.455Å. The binding properties of the complex with calf thymus DNA (CT-DNA) have been investigated by UV-vis absorption, fluorescence, CD spectra and viscosity measurement. The results indicate that the complex binds to CT-DNA in non-classical intercalative mode. Meanwhile, the interaction of the complex with bovine serum albumin (BSA) has been studied by UV-vis absorption, fluorescence and CD spectra. Results indicated that the complex can markedly quench the intrinsic fluorescence of BSA via a static quenching process, and cause its conformational change. The calculated apparent binding constant Kb was 1.05×10(6)M(-1) and the binding site number n was 1.18. PMID:23376270

  1. Synthesis, crystal structure and interaction of L-valine Schiff base divanadium(V) complex containing a V2O3 core with DNA and BSA

    NASA Astrophysics Data System (ADS)

    Guo, Qiong; Li, Lianzhi; Dong, Jianfang; Liu, Hongyan; Xu, Tao; Li, Jinghong

    2013-04-01

    A divanadium(V) complex, [V2O3(o-van-val)2] (o-van-val = Schiff base derived from o-vanillin and L-valine), has been synthesized and structurally characterized. The crystal structure shows that both of the vanadium centers in the complex have a distorted octahedral coordination environment composed of tridentate Schiff base ligand. A V2O3 core in molecular structure adopts intermediate between cis and trans configuration with the O1dbnd V1⋯V1Adbnd O1A torsion angle 115.22 (28)° and the V1⋯V1A distance 3.455 Å. The binding properties of the complex with calf thymus DNA (CT-DNA) have been investigated by UV-vis absorption, fluorescence, CD spectra and viscosity measurement. The results indicate that the complex binds to CT-DNA in non-classical intercalative mode. Meanwhile, the interaction of the complex with bovine serum albumin (BSA) has been studied by UV-vis absorption, fluorescence and CD spectra. Results indicated that the complex can markedly quench the intrinsic fluorescence of BSA via a static quenching process, and cause its conformational change. The calculated apparent binding constant Kb was 1.05 × 106 M-1 and the binding site number n was 1.18.

  2. Synthesis of Schiff bases of naphtha[1,2- d ]thiazol-2-amine and metal complexes of 2-(2?-hydroxy)benzylideneaminonaphthothiazole as potential antimicrobial agents

    Microsoft Academic Search

    Faizul Azam; Satendra Singh; Sukhbir Lal Khokhra; Om Prakash

    2007-01-01

    Objective  A series of 2-benzylideneaminonaphthothiazoles were designed and synthesized incorporating the lipophilic naphthalene ring\\u000a to render them more capable of penetrating various biomembranes.\\u000a \\u000a \\u000a \\u000a Methods  Schiff bases were synthesized by the reaction of naphtha[1,2-d]thiazol-2-amine with various substituted aromatic aldehydes. 2-(2?-Hydroxy)benzylideneaminonaphthothiazole was converted\\u000a to its Co(II), Ni(II) and Cu(II) metal complexes upon treatment with metal salts in ethanol. All the compounds were evaluated\\u000a for

  3. Reactivity of tris(acetylacetonato) iron(III) with tridentate [ONO] donor Schiff base as an access to newer mixed-ligand iron(III) complexes

    Microsoft Academic Search

    Chira R. Bhattacharjee; Pankaj Goswami; Harun A. R. Pramanik; Pradip C. Paul; Paritosh Mondal

    2011-01-01

    Two new mixed-ligand iron(III) complexes, [Fe(Ln)(acac)(C2H5OH)] incorporating coordinated ethanol from the reaction solvent were accessed from the reaction of [Fe(acac)3] with [ONO] donor dibasic tridentate unsymmetrical Schiff base ligands derived from condensation of 2-hydroxy-1-napthaldehyde with 2-aminophenol (H2L1) or 2-aminobenzoic acid (H2L2). The thermal study (TGA–DTA) provided evidence for weakly bound ethanol which is readily substituted by neutral N-donor molecule imidazole,

  4. Synthesis and characterization of Cu(II), Ni(II) and Zn(II) metal complexes of bidentate NS isomeric Schiff bases derived from S-methyldithiocarbazate (SMDTC): bioactivity of the bidentate NS isomeric Schiff bases, some of their Cu(II), Ni(II) and Zn(II) complexes and the X-ray structure of the bis[ S-methyl-?- N-(2-furyl-methyl)methylenedithiocarbazato]zinc(II) complex

    Microsoft Academic Search

    M. T. H Tarafder; Kar-Beng Chew; Karen A Crouse; A. M Ali; B. M Yamin; H.-K Fun

    2002-01-01

    Two new isomeric Schiff bases, S-methyl-?-N-(2-furylmethyl)methylenedithiocarbazate (NS?) and S-methyl-?-N-(5-methyl-2-furyl)methylenedithiocarbazate (NS?) have been prepared. Bis-chelated complexes of these two bidentate ligands, [M(NS)2], [M=Cu(II), Ni(II) and Zn(II)], were synthesized. The Schiff bases and their metal complexes have been characterized by a variety of physico-chemical techniques. X-ray crystallographic analysis shows that the Zn(II) complex, [Zn(NS?)2], is four-coordinate and has a distorted tetrahedral structure

  5. A Schiff Base-Derived Copper (II) Complex Is a Potent Inducer of Apoptosis in Colon Cancer Cells by Activating the Intrinsic Pathway

    PubMed Central

    Hajrezaie, Maryam; Paydar, Mohammadjavad; Zorofchian Moghadamtousi, Soheil; Hassandarvish, Pouya; Gwaram, Nura Suleiman; Zahedifard, Maryam; Rouhollahi, Elham; Karimian, Hamed; Looi, Chung Yeng; Ali, Hapipah Mohd; Abdul Majid, Nazia; Abdulla, Mahmood Ameen

    2014-01-01

    Metal-based drugs with extensive clinical applications hold great promise for the development of cancer chemotherapeutic agents. In the last few decades, Schiff bases and their complexes have become well known for their extensive biological potential. In the present study, we examined the antiproliferative effect of a copper (II) complex on HT-29 colon cancer cells. The Cu(BrHAP)2 Schiff base compound demonstrated a potent antiproliferative effect in HT-29 cells, with an IC50 value of 2.87??g/ml after 72?h of treatment. HT-29 cells treated with Cu (II) complexes underwent apoptosis death, as exhibited by a progressive elevation in the proportion of the G1 cell population. At a concentration of 6.25??g/ml, the Cu(BrHAP)2 compound caused significant elevation in ROS production following perturbation of mitochondrial membrane potential and cytochrome c release, as assessed by the measurement of fluorescence intensity in stained cells. Furthermore, the activation of caspases 3/7 and 9 was part of the Cu (II) complex-induced apoptosis, which confirmed the involvement of mitochondrial-mediated apoptosis. Meanwhile, there was no significant activation of caspase-8. Taken together, these results imply that the Cu(BrHAP)2 compound is a potential candidate for further in vivo and clinical colon cancer studies to develop novel chemotherapeutic agents derived from metal-based agents. PMID:24737979

  6. La(III) complex involving the O,N-donor environment of quinazoline-4(3H)-one Schiff’s base and their antimicrobial attributes against methicillin-resistant Staphylococcus aureus (MRSA)

    NASA Astrophysics Data System (ADS)

    Siddappa, K.; Mane, Sunilkumar B.; Manikprabhu, Deene

    2014-09-01

    The incidence of methicillin-resistant Staphylococcus aureus increased during the past few decades, so there is an urgent need of new antimicrobial agents if public health is concerned. Though the Schiff’s bases and La(III) complex have enormous biological activity, but less attention was given in their synthesis. In the present investigation, we synthesized a new (E)-3-((2-hydroxynaphthalen-1-yl) methyleneamino)-2-methylquinazoline-4(3H)-one HNMAMQ Schiff’s base by the condensation of 3-(2-aminophenyl) quinazolin-2-methyl-4(3H)-one and 2-hydroxy-1-naphthaldehyde. The Schiff’s base HNMAMQ and its La(III) complex were characterized by elemental analyses, IR, NMR, mass spectra, and thermal studies. The newly synthesized Schiff’s base HNMAMQ and its La(III) complex were evaluated for their antimicrobial activity against methicillin-resistant Staphylococcus aureus isolated from the Gulbarga region in India. The Schiff’s base HNMAMQ and its La(III) complex showed good antimicrobial activity and thus represents a potential new drug of choice.

  7. Pd(II) and Zn(II) Based Complexes with Schiff Base Ligands: Synthesis, Characterization, Luminescence, and Antibacterial and Catalytic Activities

    PubMed Central

    Feng, Zhi-Qiang; Yang, Xiao-Li; Ye, Yuan-Feng

    2013-01-01

    Two new metal complexes involving Schiff base ligands, namely, [Pd(L1)2] (1) and [Zn(L2)2] (2), [HL1: 2,4-dibromo-6-((E)-(mesitylimino)methyl)phenol and HL2: 2-((E)-(2,6-diisopropylphenylimino)methyl)-4,6-dibromophenol], have been solvothermally synthesized and characterized by elemental analysis, IR-spectroscopy, thermogravimetric analysis, powder X-ray diffraction, and single-crystal X-ray diffraction. Both 1 and 2 are mononuclear cyclometalated complexes with square planar and tetrahedral coordination geometry, respectively. 1 and 2 display photoluminescence in the solid state at 298?K (fluorescence lifetimes ? = 5.521??s at 508?nm for 1; ? = 3.697??s at 506?nm for 2). These Schiff base ligands and their metal complexes have been screened for antibacterial activity against several bacteria strains, and the results are compared with the activity of penicillin. Moreover, the Suzuki reaction of 4-bromoanisole with phenylboronic acid by 1 has also been studied. PMID:24307886

  8. Palladium(II) and zinc(II) complexes of neutral [N2O2] donor Schiff bases derived from furfuraldehyde: synthesis, characterization, fluorescence and corrosion inhibitors of ligands.

    PubMed

    Ali, Omyma A M

    2014-11-11

    Metal complexes of Schiff bases derived from furfuraldehyde and 4,5-dimethyl-1,2-phenylendiamine (L1) or 4,5-dichloro-1,2-phenylendiamine (L2) have been reported and characterized based on elemental analyses, IR, 1H NMR, UV-Vis, magnetic moment, molar conductance and thermal analysis. The complexes are found to have the formulae [PdL1-2]Cl2 and [ZnL1-2](AcO)2·H2O. The molar conductance data reveal that Pd(II) and Zn(II) chelates are ionic in nature and are of the type 2:1 electrolytes. The spectral data are consistent with a square planar and tetrahedral geometry around Pd(II) and Zn(II), respectively, in which the ligands act as tetradentate ligands. The thermal behavior of some chelates is studied and the activation thermodynamic parameters are calculated using Coats-Redfern method. The corrosion inhibition of stainless steel types 410 and 304 in 1 M HCl using the synthesized Schiff bases as inhibitors have been studied by weight loss method. The obtained data considered these ligands as efficient corrosion inhibitors. The ligands and their metal complexes exhibited considerable antibacterial activity against Staphylococcusaureus, and Escherichiacoli and antifungal activity against Candida albicans. PMID:24858346

  9. The adsorption of monomers (metal complexes with Schiff bases) and the structure and properties of polymeric films formed on the surface of graphite

    Microsoft Academic Search

    B. N. Afanas'ev; Yu. A. Polozhentseva; A. M. Timonov

    2010-01-01

    The adsorption of nickel(II) and copper(II) complexes with the N,N'-ethylenebis(salicylideneimine) ligand on carbonaceous materials and at the air-solution boundary was studied. A correlation was observed between adsorption parameters and the structure of polymeric films formed as a result of the electrode oxidation of these compounds (monomers).

  10. The adsorption of monomers (metal complexes with Schiff bases) and the structure and properties of polymeric films formed on the surface of graphite

    Microsoft Academic Search

    B. N. Afanas’ev; Yu. A. Polozhentseva; A. M. Timonov

    2010-01-01

    The adsorption of nickel(II) and copper(II) complexes with the N,N?-ethylenebis(salicylideneimine) ligand on carbonaceous\\u000a materials and at the air-solution boundary was studied. A correlation was observed between adsorption parameters and the structure\\u000a of polymeric films formed as a result of the electrode oxidation of these compounds (monomers).

  11. Construction and NIR luminescent property of hetero-bimetallic Zn Nd complexes from two chiral salen-type Schiff-base ligands

    NASA Astrophysics Data System (ADS)

    Bi, Wei-Yu; Lü, Xing-Qiang; Chai, Wen-Li; Song, Ji-Rong; Wong, Wai-Yeung; Wong, Wai-Kwok; Jones, Richard A.

    2008-11-01

    Two new near-infrared (NIR) luminescent Zn-Nd complexes [ZnL 1Nd(OAc)(NO 3) 2] ( 3) and [ZnL 2Nd(DMF) 2(NO 3) 3] ( 4) have been obtained with two salen-type Schiff-base ligands H 2L 1 and H 2L 2, ( H 2L 1 = N, N'-bis(3-methoxysalicylidene)-(1s, 2s)-(-)1,2-dipheneylethylenediamine and H 2L 2 = N, N'-bis(3-methoxysalicylidene)-(s)-2,2-diamine-1,1'-binaphthyl) from the reaction of different chiral diamines with o-vanillin. The X-ray crystal structure analysis reveals that both of them crystallize in the chiral space groups with P2(1), a = 10.1669(6), b = 19.3775(11), c = 17.4639(10) Å, ? = 94.8710(10)°, V = 3428.1(3) Å 3, Z = 4 for 3, and C2, a = 22.1914(13), b = 9.7886(6), c = 22.0138(13) Å, ? = 118.9590(10)°, V = 4372.5(4) Å 3, Z = 4 for 4. Complexes 3- 4 are both dinuclear Zn-Nd structures, while suitable choice of chiral Schiff-base ligands could induce the different complexions of ligands and metal ions, and the functional control of ligand character shows a potentially effective way to the fine-tuning properties of NIR luminescence from Nd ions.

  12. Synthesis, spectral, thermal and thermodynamic studies of oxovanadium(IV) complexes of Schiff bases derived from 3,4-diaminobenzoic acid with salicylaldehyde derivatives

    NASA Astrophysics Data System (ADS)

    Mohammadi, Khosro; Niad, Mahmood; Irandoost, Amene

    2013-04-01

    Synthesis and evaluation of three new oxovanadium(IV) complexes, formed by the interaction of vanadyl acetylacetonate and the Schiff bases: 3,4-bis((E)-2-hydroxybenzylideneamino)benzoic acid (L1), 3,4-bis-((E)-2-hydroxy-3-methoxybenzylideneamino)benzoic acid (L2) and 3,4-bis((E)-2,4-dihydroxybenzylideneamino)benzoic acid (L3) in methanol. The complexes have been characterized and studied by IR spectra, UV-Vis spectroscopy and thermogravimetry in order to evaluate their thermal stability and thermal decomposition. According to the results discussed from TG curves, the order of thermal stability for the complexes is VOL3 > VOL1 > VOL2. Their formation constants (Kf) were obtained by UV-Vis spectroscopic titration at 15, 25, 35 and 45 °C in methanol by SQUAD software. The trend of formation constants of the complexes as follows: VOL3 > VOL2 > VOL1.

  13. Synthesis, spectroscopic characterization and antimicrobial studies of Co(II), Ni(II), Cu(II) and Zn(II) complexes with Schiff bases derived from 5-bromo-salicylaldehyde

    NASA Astrophysics Data System (ADS)

    Kursunlu, Ahmed Nuri; Guler, Ersin; Sevgi, Fatih; Ozkalp, Birol

    2013-09-01

    In this study, the new Schiff base ligands derived from condensation of amine and 5-bromo-salicylaldehyde were characterized. All compounds, the Schiff bases and the metal complexes, were characterized by elemental analyzes, FT-IR, 1H NMR, 13C NMR and magnetic susceptibility measurements. The synthesized ligands, along with their metal (II) complexes, were screened for their in vitro antibacterial activity against four Gram-negative (Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa and Salmonella enteritidis) and four Gram-positive (Streptococcus pyogones, Bacillus cereus, Staphylococcus aureus and Methicillin-resistant S. aureus) bacterial strains by using disc diffusion and broth microdilution techniques.

  14. 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

  15. Biological activity of palladium(II) and platinum(II) complexes of the acetone Schiff bases of S-methyl- and S-benzyldithiocarbazate and the X-ray crystal structure of the [Pd(asme) 2] (asme=anionic form of the acetone Schiff base of S-methyldithiocarbazate) complex

    Microsoft Academic Search

    Mohammad Akbar Ali; Aminul Huq Mirza; Raymond J Butcher; M. T. H Tarafder; Tan Boon Keat; A. Manaf Ali

    2002-01-01

    Palladium(II) and platinum(II) complexes of general empirical formula, [M(NS)2] (NS=uninegatively charged acetone Schiff bases of S-methyl- and S-benzyldithiocarbazate; M=PtII and PdII) have been prepared and characterized by a variety of physicochemical techniques. Based on conductance, IR and electronic spectral evidence, a square-planar structure is assigned to these complexes. The crystal and molecular structure of the [Pd(asme)2] complex (asme=anionic form of

  16. Synthesis, characterization and biological studies of sulfonamide Schiff's bases and some of their metal derivatives.

    PubMed

    Chohan, Zahid H; Shad, Hazoor A; Supuran, Claudiu T

    2012-02-01

    A new series of Schiff base ligands derived from sulfonamide and their metal(II) complexes [cobalt(II), copper(II), nickel(II) and zinc(II)] have been synthesized and characterized. The nature of bonding and structure of all the synthesized compounds has been explored by physical, analytical and spectral data of the ligands and their metal(II) complexes. The authors suggest that all the prepared complexes possess an octahedral geometry. The ligands and metal(II) complexes have been screened for their in vitro antibacterial activity against bacterial strains, Escherichia coli, Shigella flexneri, Pseudomonas aeruginosa, Salmonella typhi and for antifungal activity against fungal strains, Trichophyton longifusus, Candida albicans, Aspergillus flavus, Microsporum canis, Fusarium solani and Candida glabrata. These assays enabled the identification of the metal complexes as an effective antimicrobial agent with low cytotoxicity. PMID:21534864

  17. Biological activity of palladium(II) and platinum(II) complexes of the acetone Schiff bases of S-methyl- and S-benzyldithiocarbazate and the X-ray crystal structure of the [Pd(asme)2] (asme=anionic form of the acetone Schiff base of S-methyldithiocarbazate) complex.

    PubMed

    Akbar Ali, Mohammad; Mirza, Aminul Huq; Butcher, Raymond J; Tarafder, M T H; Keat, Tan Boon; Ali, A Manaf

    2002-11-25

    Palladium(II) and platinum(II) complexes of general empirical formula, [M(NS)(2)] (NS=uninegatively charged acetone Schiff bases of S-methyl- and S-benzyldithiocarbazate; M=Pt(II) and Pd(II)) have been prepared and characterized by a variety of physicochemical techniques. Based on conductance, IR and electronic spectral evidence, a square-planar structure is assigned to these complexes. The crystal and molecular structure of the [Pd(asme)(2)] complex (asme=anionic form of the acetone Schiff base of S-methyldithiocarbazate) has been determined by X-ray diffraction. The complex has a distorted cis-square planar structure with the ligands coordinated to the palladium(II) ions as uninegatively charged bidentate NS chelating agents via the azomethine nitrogen and the mercaptide sulfur atoms. The distortion from a regular square-planar geometry is attributed to the restricted bite angles of the ligands. Antimicrobial tests indicate that the Schiff bases exhibit strong activities against the pathogenic bacteria, Bacillus subtilis (mutant defective DNA repair), methicillin-resistant Staphylococcus aureus, B. subtilis (wild type) and Pseudomonas aeruginosa and the fungi, Candida albicans (CA), Candida lypotica (2075), Saccharomyces cerevisiae (20341) and Aspergillus ochraceous (398)-the activities exhibited by these compounds being greater than that of the standard antibacterial and antifungal drugs, streptomycin and nystatin, respectively. The palladium(II) and platinum(II) complexes are inactive against most of these organisms but, the microbe, Pseudomonas aeruginosa shows strong sensitivity to the platinum(II) complexes. Screening of the compounds for their cytotoxicities against T-lymphoblastic leukemia cancer cells has shown that the acetone Schiff base of S-methyldithiocarbazate (Hasme) exhibits a very weak activity, whereas the S-benzyl derivative (Hasbz) is inactive. However, the palladium(II) complexes exhibit strong cytotoxicities against this cancer; their activities being more than that of the standard anticancer drug, tamoxifen. The [Pt(asme)(2)] complex exhibits a very weak cytotoxicity, whereas [Pt(asbz)(2)] is inactive against leukemic cells. PMID:12433421

  18. Transition metal complexes of a new hexadentate macroacyclic N2O4-donor Schiff base: inhibitory activity against bacteria and fungi.

    PubMed

    Patil, Manjula; Hunoor, Rekha; Gudasi, Kalagouda

    2010-07-01

    A new hexadentate macroacyclic N(2)O(4) - donor ligand, glyoxal bis(N-nitroso phenylglycine) (gbnp), has been designed and structurally characterized. Manganese(II), cobalt(II), nickel(II), copper(II) and zinc(II) complexes of gbnp have been prepared and characterized by elemental analyses, molar conductance measurements, magnetic moment, spectral (IR, (1)H NMR, electronic and FAB mass) and thermal studies. The molecular dynamics of the ligand was studied by the variable temperature NMR studies, which suggest the presence of two isomeric forms. The antimicrobial activity of all the compounds was studied against Escherichia coli, Bacillus cirroflagellosus, Aspergillus niger and Candida albicans. Among the new complexes, copper(II) complex has the highest potential against all the microorganisms tested. PMID:20416985

  19. Syntheses, characterization and crystal structures of two square-planar Ni(II) complexes with unsymmetrical tridentate Schiff base ligands and monodentate pseudohalides

    Microsoft Academic Search

    Shyamapada Shit; Soma Sen; Samiran Mitra; David L. Hughes

    2009-01-01

    Two new square-planar Ni(II) complexes, [NiL1(NCS)] (1) and [NiL2(N3)] (2) have been synthesized with the unsymmetrical tridentate Schiff base ligands [(CH3)2NCH2CH2N=C(CH3)CH=C(OH)(C6H5)], L\\u000a \\u000a 1\\u000a \\u000a H, derived from benzoylacetone and 2-dimethylaminoethylamine and [(CH3CH2)2NCH2CH2N=C(CH3)CH=C(OH)(C6H5)], L\\u000a \\u000a 2\\u000a \\u000a H, derived from benzoylacetone and 2-diethylaminoethylamine, respectively. The complexes have been characterized by elemental\\u000a analysis, FT-IR, UV-Vis spectroscopy, electrochemical and thermal methods (where applicable). Structures have been

  20. Grafting of a rhenium-oxo complex on Schiff base functionalized graphene oxide: an efficient catalyst for the oxidation of amines.

    PubMed

    Khatri, Praveen K; Choudhary, Shivani; Singh, Raghuvir; Jain, Suman L; Khatri, Om P

    2014-06-01

    A rhenium-oxo complex such as methyltrioxorhenium (MTO) has been homogeneously immobilized on a Schiff base modified graphene oxide (GrO) support via covalent bonding. The loading of MTO on GrO nanosheets was monitored by FTIR, TG-DTA, and elemental analyses. The developed heterogeneous catalyst is found to be efficient for the oxidation of various amines to the corresponding N-oxides using hydrogen peroxide as an oxidant in high to excellent yields. At the end of the reaction, the catalyst is readily recovered by filtration and reused for subsequent runs. After the third run, the catalyst showed a marginal decrease in catalytic activity owing to the leaching of the MTO complex from the support. PMID:24718600

  1. Synthesis and spectral characterization of Schiff base complexes of Cu(II), Co(II), Zn(II) and VO(IV) containing 4-(4-aminophenyl)morpholine derivatives: Antimicrobial evaluation and anticancer studies

    NASA Astrophysics Data System (ADS)

    Dhahagani, K.; Mathan Kumar, S.; Chakkaravarthi, G.; Anitha, K.; Rajesh, J.; Ramu, A.; Rajagopal, G.

    2014-01-01

    Metal(II) chelates of Schiff bases derived from the condensation of 4-morpholinoaniline with substituted salicylaldehyde have been prepared and characterized by 1H NMR, IR, electronic, EPR, and magnetic measurement studies. The complexes are of the type M(X-MPMP)2 [where M = Cu(II), Co(II)), Zn(II), or VO(IV); MPMP = 2-[(4 morpholinophenyl imino) methyl] 4-X-phenol, X = Cl, (L1H), X = Br (L2H)]. Single crystal X-ray crystallography studies confirm the structure of newly synthesized Schiff bases. The Schiff bases act as bidentate monobasic ligands, coordinating through deprotonated phenolic oxygen and azomethine nitrogen atoms. The free ligands and metal complexes are screened for their biopotency. Metal complexes exhibit better activity than ligands. Anticancer activity of ligands and their metal complexes are evaluated in human heptocarcinoma(HepG2) cells. The preliminary bioassay indicates that the Schiff base and its zinc complex exhibit inhibitory activity against the human gastric cancer cell lines.

  2. New homoleptic metal complexes of Schiff bases derived from 2,4-di-p-tolyl-3-azabicyclo[3.3.1]nonan-9-one

    Microsoft Academic Search

    Mohamad Jaber Al-Jeboori; Mahmoud Saleh Al-Fahdawi; Ausama A. Sameh

    2009-01-01

    New bidentate Schiff-base ligands 2-(2,4-di-p-tolyl-3-azabicyclo[3.3.1]nonan-9-ylidene)hydrazinecarbothioamide HL and 2-(2,4-di-p-tolyl-3-azabicyclo[3.3.1]nonan-9-ylidene)hydrazinecarboxamide HL were synthesized from the condensation of 2,4-di-p-tolyl-3-azabicyclo[3.3.1]nonan-9-one with thiosemicarbazide and semicarbazide, respectively. Homoleptic complexes of these ligands, of general formula K[Cr(L)2Cl2], K2[Mn(L)2Cl2], K2[Fe(L)2Cl2] and [M(L)2] (where M = Co(II), Ni(II) Cu(II), Zn(II), Cd(II), and Hg(II) ions; n = 1 or 2) are reported. The mode of bonding and overall geometry of

  3. Photoinduced electron transfer from PbS quantum dots to cobalt(III) Schiff base complexes: light activation of a protein inhibitor

    PubMed Central

    Peterson, Mark D.; Holbrook, Robert J.; Meade, Thomas J.; Weiss, Emily A.

    2013-01-01

    This paper describes the activation of a biologically inert Co(III) Schiff base (SB) complex to its protein inhibitor form by photoinduced electron transfer (PET) from a colloidal PbS quantum dot (QD, radii = 1.5 – 1.7 nm) to the cobalt center, with a charge separation time constant of 125 ns. Reduction of the Co(III)-SB initiates release of the native axial ligands, promoting replacement with the histidine mimic 4-methylimidazole. The rate of ligand displacement increases by approximately a factor of eight upon exposure of the PbS QD/Co(III)-SB mixture to light of energy greater than the energy of the first excitonic state of the QDs, from which PET occurs. These results suggest an approach for the preparation of inorganic therapeutic agents that can be specifically coupled to a biologically active site by cooperative redox-binding ligation. PMID:23931454

  4. Synthesis, characterization, fluorescence and catalytic activity of some new complexes of unsymmetrical Schiff base of 2-pyridinecarboxaldehyde with 2,6-diaminopyridine

    NASA Astrophysics Data System (ADS)

    Ali, Omyma A. M.; El-Medani, Samir M.; Ahmed, Doaa A.; Nassar, Doaa A.

    2015-06-01

    The Schiff base, 2-[(pyridin-2-ylmethylidene)amino]-6-aminopyridine (L) was synthesized by 1:1 condensation of 2-pyridinecarboxaldehyde and 2,6-diaminopyridine. The ligand and its complexes were characterized by different physicochemical studies. The analytical and spectroscopic tools indicated that the synthesized complexes have the general formulae: [M(L)Cl2]·2H2O (M = Cu(II), Ni(II) and Co(II)), [La(L)3](NO3)3·3H2O and [Sm(L)(ClO4)3]·3H2O. Vibrational spectra indicated the coordination of L to metal ions through its pyridyl and azomethine nitrogen atoms. The presence of water molecules in all reported complexes has been supported by TG/DTA studies. Kinetic and thermodynamic parameters were computed using Coats and Redfern method. The prepared ligand and its complexes exhibited intraligand (?-??) fluorescence and can potentially serve as photoactive materials. The catalytic activity of the complexes toward the decomposition of hydrogen peroxide was investigated. Both the ligand and its complexes have been screened for antibacterial activities.

  5. Reactivity of tris(acetylacetonato) iron(III) with tridentate [ONO] donor Schiff base as an access to newer mixed-ligand iron(III) complexes

    NASA Astrophysics Data System (ADS)

    Bhattacharjee, Chira R.; Goswami, Pankaj; Pramanik, Harun A. R.; Paul, Pradip C.; Mondal, Paritosh

    2011-05-01

    Two new mixed-ligand iron(III) complexes, [Fe(L n)(acac)(C 2H 5OH)] incorporating coordinated ethanol from the reaction solvent were accessed from the reaction of [Fe(acac) 3] with [ONO] donor dibasic tridentate unsymmetrical Schiff base ligands derived from condensation of 2-hydroxy-1-napthaldehyde with 2-aminophenol (H 2L 1) or 2-aminobenzoic acid (H 2L 2). The thermal study (TGA-DTA) provided evidence for weakly bound ethanol which is readily substituted by neutral N-donor molecule imidazole, benzimidazole or pyridine to produce an array of newer complexes, [Fe(L n)(acac)X] ( n = 1, 2; X = Im, Bim, Py). The compounds were characterized by elemental analyses, FT-IR, UV-vis, solution electrical conductivity, FAB mass, 1H and 13C NMR spectroscopy. Room temperature magnetic susceptibility measurements ( ?eff ˜ 5.8 B.M.) are consistent with spin-free octahedral iron(III) complexes. Cyclic voltammetry of ethanol complexes revealed a quasi-reversible one electron redox response (? Ep > 100 mV) for the Fe(III)/Fe(II) couple. Low half wave redox potential ( E1/2) values suggested easy redox susceptibility. The ground state geometries of the ethanol and imidazole complexes have been ascertained to be distorted octahedral by density functional theory using DMol3 program at BLYP/DNP level.

  6. Palladium(II) and platinum(II) complexes of a symmetric Schiff base derived from 2,6,diformyl-4-methylphenol with N-aminopyrimidine: Synthesis, characterization and detection of DNA interaction by voltammetry

    Microsoft Academic Search

    Mehmet Sönmez; Metin Çelebi; Yavuz Yard?m; Zühre ?entürk

    2010-01-01

    The two new mononuclear complexes were prepared by reacting symmetric Schiff base, containing pyrimidine rings and the metal chlorides of Pd(II) and Pt(II) in methanol. The mononuclear structure of the complexes was confirmed on the basis of elemental analyses, magnetic susceptibility, IR, UV–Vis, NMR, DTA\\/TGA and API-ES mass spectral data. The interaction of these metal complexes with fish sperm double-stranded

  7. Synthesis and characterization of Co(II), Ni(II), Cu(II) and Zn(II) complexes of tridentate Schiff base derived from vanillin and DL-?-aminobutyric acid

    NASA Astrophysics Data System (ADS)

    Nair, M. Sivasankaran; Joseyphus, R. Selwin

    2008-09-01

    Co(II), Ni(II), Cu(II) and Zn(II) complexes of the Schiff base derived from vanillin and DL-?-aminobutyric acid were synthesized and characterized by elemental analysis, IR, electronic spectra, conductance measurements, magnetic measurements, powder XRD and biological activity. The analytical data show the composition of the metal complex to be [ML(H 2O)], where L is the Schiff base ligand. The conductance data indicate that all the complexes are non-electrolytes. IR results demonstrate the tridentate binding of the Schiff base ligand involving azomethine nitrogen, phenolic oxygen and carboxylato oxygen atoms. The IR data also indicate the coordination of a water molecule with the metal ion in the complex. The electronic spectral measurements show that Co(II) and Ni(II) complexes have tetrahedral geometry, while Cu(II) complex has square planar geometry. The powder XRD studies indicate that Co(II) and Cu(II) complexes are amorphous, whereas Ni(II) and Zn(II) complexes are crystalline in nature. Magnetic measurements show that Co(II), Ni(II) and Cu(II) complexes have paramagnetic behaviour. Antibacterial results indicated that the metal complexes are more active than the ligand.

  8. Transition metal complexes with Girard reagent-based ligands, Part I: Synthesis and crystal structure of the first cobalt(III) complexes with Schiff base derivative of Girard reagent

    Microsoft Academic Search

    Ljiljana S. Vojinovi?; Vukadin M. Leovac; Sladjana B. Novakovi?; Goran A. Bogdanovi?; János J. Csanádi; Valerija I. ?ešljevi?

    2004-01-01

    A new ligand, pyridoxilidene Girard-T hydrazone, [H3L]Cl2·2H2O, and its octahedral cobalt(III) complexes [Co(HL)(NO2)3]·H2O (1) and [Co(HL)2](PF6)3 (2) were synthesized. The X-ray analysis of (1) showed that the complex has a mer-octahedral configuration formed by coordination of the tridentate ONO neutral Schiff-base molecule and three monodentate N-bonded NO2 groups. Hydrogen bonds and intermolecular interactions for this complex are discussed. Complex (2)

  9. Cu(II), Co(II) and Ni(II) complexes of new Schiff base ligand: Synthesis, thermal and spectroscopic characterizations

    NASA Astrophysics Data System (ADS)

    Refat, Moamen S.; El-Sayed, Mohamed Y.; Adam, Abdel Majid A.

    2013-04-01

    Cu(II), Co(II), and Ni(II) complexes were synthesized from 2-[(5-o-chlorophenylazo-2-hydroxybenzylidin)amino]-phenol Schiff base (H2L). Metal ions coordinate in a tetradentate or hexadentate features with these O2N donor ligand, which are characterized by elemental analyses, magnetic moments, infrared, Raman laser, electronic, and 1H NMR spectral studies. The elemental analysis suggests the stoichiometry to be 1:1 (metal:ligand). Reactions with Cu(II), Co(II) and Ni(II), resulted [Cu(H2L)(H2O)2(Cl)]Cl, [Co(H2L)(H2O)3]Cl2?3H2O and [Ni(H2L)(H2O)2]Cl2?6H2O. The thermal decomposition behavior of H2L complexes has been investigated by thermogravimetric analysis (TG/DTG) at a heating rate of 10 °C min-1 under nitrogen atmosphere. The brightness side in this study is to take advantage for the preparation and characterizations of single phases of CuO, CoO and NiO nanoparticles using H2L complexes as precursors via a solid-state decomposition procedure. The crystalline structures of products using X-ray diffractometer (XRD), morphology of particles by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX) were investigated.

  10. A new tridentate Schiff base Cu(II) complex: Synthesis, experimental and theoretical studies on its crystal structure, FT-IR and UV-Visible spectra

    NASA Astrophysics Data System (ADS)

    Saheb, Vahid; Sheikhshoaie, Iran; Setoodeh, Nasim; Rudbari, Hadi Amiri; Bruno, Giuseppe

    2013-06-01

    A new Cu(II) complex [Cu(L)(NCS)] has been synthesized, using 1-(N-salicylideneimino)-2-(N,N-methyl)-aminoethane as tridentate ONN donor Schiff base ligand (HL). The dark green crystals of the compound are used for single-crystal X-ray analysis and measuring Fourier Transform Infrared (FT-IR) and UV-Visible spectra. Electronic structure calculations at the B3LYP and MP2 levels of theory are performed to optimize the molecular geometry and to calculate the UV-Visible and FT-IR spectra of the compound. Vibrational assignments and analysis of the fundamental modes of the compound are performed. Time-dependent density functional theory (TD-DFT) method is used to calculate the electronic transitions of the complex. A scaling factor of 1.015 is obtained for vibrational frequencies computed at the B3LYP level using basis sets 6-311G(d,p). It is found that solvent has a profound effect on the electronic absorption spectrum. The UV-Visible spectrum of the complex recorded in DMSO and DMF solution can be correctly predicted by a model in which DMSO and DMF molecules are coordinated to the central Cu atom via their oxygen atoms.

  11. A new tridentate Schiff base Cu(II) complex: synthesis, experimental and theoretical studies on its crystal structure, FT-IR and UV-Visible spectra.

    PubMed

    Saheb, Vahid; Sheikhshoaie, Iran; Setoodeh, Nasim; Rudbari, Hadi Amiri; Bruno, Giuseppe

    2013-06-01

    A new Cu(II) complex [Cu(L)(NCS)] has been synthesized, using 1-(N-salicylideneimino)-2-(N,N-methyl)-aminoethane as tridentate ONN donor Schiff base ligand (HL). The dark green crystals of the compound are used for single-crystal X-ray analysis and measuring Fourier Transform Infrared (FT-IR) and UV-Visible spectra. Electronic structure calculations at the B3LYP and MP2 levels of theory are performed to optimize the molecular geometry and to calculate the UV-Visible and FT-IR spectra of the compound. Vibrational assignments and analysis of the fundamental modes of the compound are performed. Time-dependent density functional theory (TD-DFT) method is used to calculate the electronic transitions of the complex. A scaling factor of 1.015 is obtained for vibrational frequencies computed at the B3LYP level using basis sets 6-311G(d,p). It is found that solvent has a profound effect on the electronic absorption spectrum. The UV-Visible spectrum of the complex recorded in DMSO and DMF solution can be correctly predicted by a model in which DMSO and DMF molecules are coordinated to the central Cu atom via their oxygen atoms. PMID:23562742

  12. Synthesis, Characterization of Some Transition-Metal Complexes of a New Heptadentate N5S2 Schiff-Base Ligand and the Effects of These Metal Complexes on U2OS Cells Cytotoxicity and DNA Cleavage Activity

    Microsoft Academic Search

    G. Uluçcam; N. Beynek; Z. Seller; G. Akal?n; G. Turan; K. Benkli

    2008-01-01

    Metal complexes of a heptadentate N5S2 donor Schiff-base ligand were synthesized by the template reaction between 2,6-bis(2-aminothiophenoxymethyl)pyridine and 2,2 ?-bipyridine-6,6 ?-dicarboxaldehyde in the presence of Zn(II), Cd(II), Hg(II) and Pb(II) perchlorate salts. The complexes were characterized by IR, H NMR, MS-FAB, and elemental analyses. The mitochondrial activity of U2OS cells after exposure to these complexes was determined by colorimetric assay,

  13. A comparative study on half-inhibitory concentration of Schiff base-metal complexes reacting with bacteria 1 This project was supported by the National Foundation of China. 1

    Microsoft Academic Search

    Huang Zaiyin; Liu Yi; Qu Songsheng; Feng Ying

    1998-01-01

    The metabolic inhibition of the three series of SG, O-VG and 2,4-L totaling eleven kinds of Schiff base complexes and two kind of corresponding metal compounds on Aerobacter aerogenes and Staphylococcus sureus has been studied microcalorimetrically. The studies reveal how, with reaction of different complexes, the difference in the metabolic power–time curves of the two kinds of bacteria metabolism. According

  14. Synthesis, spectroscopic, thermal and antimicrobial studies of some novel metal complexes of Schiff base derived from [ N 1-(4-methoxy-1,2,5-thiadiazol-3-yl)sulfanilamide] and 2-thiophene carboxaldehyde

    Microsoft Academic Search

    Carmen M. Sharaby

    2007-01-01

    Keeping in view the chemotherapeutic of the sulfa-drugs, Schiff base namely 2-thiophene carboxaldehyde-sulfametrole (HL) and its tri-positive and di-positive metal complexes have been synthesized and characterized by elemental analyses, IR, 1H NMR, solid reflectance, magnetic moment, molar conductance, mass spectra, UV–vis and thermal analysis (TGA and DrTG). The low molar conductance values suggest the non-electrolytic nature of these complexes. IR

  15. Spectroscopic Elucidation of the Inhibitory Mechanism of Cys2His2 Zinc Finger Transcription Factors by CobaltIII Schiff Base Complexes

    PubMed Central

    Heffern, Marie C.; Kurutz, Josh

    2014-01-01

    Transcription factors are key regulators in both normal and pathological cell processes. Affecting the activity of these proteins is a promising strategy for understanding gene regulation and developing effective therapeutics. CoIII Schiff base complexes ([Co(acacen)(L)2]+ where L = labile axial ligands) have been shown to be potent inhibitors of a number of zinc metalloproteins including Cys2His2 zinc finger transcription factors. Inhibition by [Co(acacen)(L)2]+ of the target protein is believed to occur through a dissociative exchange of the labile axial ligands for histidine (His) residues essential for function. Here, we report a series of spectroscopic investigations with model peptides of zinc fingers that elucidate the interaction between [Co(acacen)(L)2]+ complexes and zinc finger transcription factors. Observed changes in NMR chemical shifts and 2D 1H-1H NOESY NMR spectra demonstrate the preference of [Co(acacen)(L)2]+ complexes to coordinate His residues over other amino acids. The conformation of [Co(acacen)(L)2]+ upon His-coordination was characterized by 1H NMR, near-UV circular dichroism, and electronic absorption. These studies reveal that the resulting His-coordinated [Co(acacen)(L)2]+ complex possesses an octahedral structure. The effects of [Co(acacen)(L)2]+ complexes on the zinc finger structure were assessed by the degree of hydrogen bonding (probed by 2D NMR) and secondary structure profiles measured by far-UV circular dichroism. These structural studies demonstrate the ability of [Co(acacen)(L)2]+ complexes to disrupt the ??? structure of zinc fingers, resulting in primarily random coil conformations. A mechanism is described wherein [Co(acacen)(L)2]+ complexes inhibit zinc finger transcription factor activity through selectively coordinating His residues in the zinc finger via dissociative ligand exchange and disrupting the ??? structural motif required for gene regulation. PMID:24203451

  16. Cu(II), Co(II) and Ni(II) complexes of –Br and –OCH 2 CH 3 substituted Schiff bases as corrosion inhibitors for aluminium in acidic media

    Microsoft Academic Search

    A. Aytaç

    2010-01-01

    A group of Cu(II), Ni(II) and Co(II) complexes of –Br and –OCH2CH3 substituted Schiff bases as a new class of corrosion inhibitors for aluminium has been studied in 0.1 M HCl by the addition\\u000a of 10 ppm compound using potentiodynamic polarization, electrochemical impedance spectroscopy, linear polarization methods\\u000a and gas evolution tests at 25 °C. The inhibition efficiencies obtained from all methods employed are

  17. Synthesis and characterization of a series of transition metal complexes with a new symmetrical polyoxaaza macroacyclic Schiff base ligand: X-ray crystal structure of cobalt(II) and nickel(II) complexes and their antibacterial properties.

    PubMed

    Keypour, Hassan; Shayesteh, Maryam; Rezaeivala, Majid; Chalabian, Firoozeh; Valencia, Laura

    2013-01-15

    A new symmetrical [N4O2] hexadentate Schiff base ligand, (E)-N-(pyridin-2-ylmethylene)-2-(3-(2-((E)-pyridin-2-lmethyleneamino)phenoxy)naphthalen-2-yloxy)benzenamine, abbreviated to L, and its complexes of Ni(II), Cu(II), Zn(II), Co(II), Cd(II) and Mn(II) have been synthesized in the presence of metal ions. The complexes were structurally characterized by elemental analyses, IR, UV-Vis, NMR and molar conductivity. The crystal structures of two complexes, [NiL(ONO2)2]·2H2O and [CoLCl2]CH3OH·0.5H2O, have been determined by a single crystal X-ray diffraction study. In these complexes, the ligand is coordinated in a neutral form via pyridine and azomethine nitrogen atoms. The metal ions complete their six coordination with two coordinated nitrate or chloride ions, forming a distorted octahedral geometry. The synthesized compounds have antibacterial activity against the three Gram-positive bacteria: Enterococcus faecalis, Bacillus cereus and Staphylococcus epid and also against the three Gram-negative bacteria: Citrobacter freundii, Enterobacter aerogenes and Salmonella typhi. The activity data show that the complexes are more potent antibacterials than the parent Schiff base. PMID:23099161

  18. Synthesis, characterization, crystal structure determination, computational study, and thermal decomposition into NiO nano-particles of a new NiIIL2 Schiff base complex (L = 2-{(E)-[2-chloroethyl)imino]methylphenolate)

    NASA Astrophysics Data System (ADS)

    Grivani, Gholamhossein; Vakili, Mohammad; Khalaji, Aliakbar Dehno; Bruno, Giuseppe; Rudbari, Hadi Amiri; Taghavi, Maedeh; Tahmasebi, Vida

    2014-08-01

    The Nickel (II) Schiff base complex of NiL2, (L = 2-{(E)-[2-chloroethyl) imino]methylphenolate) have been synthesized and characterized by elemental (CHN) analysis, UV-vis and FT-IR spectroscopy. The molecular structure of [NiL2] was determined by single crystal X-ray diffraction technique. The Schiff base ligand HL acts as a chelating ligand and coordinates via one nitrogen atom and one oxygen atom to the metal center. The nickel (II) center is coordinated by two nitrogen and two oxygen atoms from two Schiff base ligands in an approximately square planar trans-[MN2O2] coordination geometry. Thermogravimetric analysis of NiL2 showed that it decomposed in three stages. In addition, complex NiL2 thermally decomposed in air at 660 °C and the XRD pattern of the obtained solid showed the formation of NiO nanoparticles with an average size of 43 nm. In addition, the conformational analysis and molecular structures of NiL2 were investigated by means of density functional theory (DFT) calculations at B3LYP/6-311G* level and the calculated geometrical parameters were compared with the experimental results.

  19. Oxovanadium(IV) complexes of bioinorganic and medicinal relevance: Synthesis, characterization and 3D molecular modeling and analysis of some oxovanadium(IV) complexes involving the O, N-donor environment of pyrazolone-based sulfa drug Schiff bases

    NASA Astrophysics Data System (ADS)

    Maurya, R. C.; Rajput, S.

    2006-08-01

    Four new oxovanadium(IV) complexes, formed by the interaction of vanadyl sulfate pentahydrate and the Schiff bases derived from 3-methyl-1-phenyl-4-valeryl-2-pyrazolin-5-one and the sulfa drugs, N-(3'-methyl-1'-phenyl-4'-valerylidene-2'-pyrazolin-5'-one)sulfadiazine (L 1H), N-(3'-methyl-1'-phenyl-4'-valerylidene-2'-pyrazolin-5'-)sulfaguanidine (L 2H), N-(3'-methyl-1'-phenyl-4'-valerylidene-2'-pyrazolin-5'-one)sulphanilamide (L 3H) and N'(-3'-methyl-1'-phenyl-4'-valerylidene-2'-pyrazolin-5'-one)sulphamethoxazole (L 4H) in aqueous ethanol are described. The resulting complexes were characterized by elemental analyses, molar conductances, magnetic and decomposition temperature measurements, cyclic voltammetry, electron spin resonance, infrared and electronic spectral studies. They have the composition [VO(L) 2]·H 2O, where LH=Schiff base L 1H, L 2H, L 3H or L 4H mentioned above. A square-pyramidal structure having a slight ⋯V dbnd6 O⋯V dbnd6 O⋯ type interaction has been proposed for these complexes.

  20. Synthesis, spectral characterization, computational calculations and biological activity of complexes designed from NNO donor Schiff-base ligand

    NASA Astrophysics Data System (ADS)

    El-Gammal, Ola A.; El-Reash, G. M. Abu; Yousef, T. A.; Mefreh, M.

    2015-07-01

    A new series of Co(II), Ni(II) and Cu(II) complexes of (Z)-2-oxo-2-(phenylamino)-N?-(1-(pyridin-2-yl)ethylidene)acetohydrazide (H2OPPAH) have been prepared and characterized by conventional techniques. The spectral data indicated that the ligand acts as neutral or mononegative NNO tridentate. On the basis of magnetic and electronic spectral data an octahedral geometry for Ni(II) and Cu(II) complexes and a tetrahedral geometry for Co(II) complex have been proposed. The molecular modeling using DFT method are drawn showing the bond length, bond angle, chemical reactivity, energy components (kcal/mol) and binding energy (kcal/mol) for all title compounds. The Kinetic parameters were determined for each thermal degradation stages of the ligand and its complexes using Coats-Redfern and Horowitz-Metzger methods. Also, the compounds were screened for antioxidant activity using ABTS free radical, anti-hemolytic, and in vitro cytotoxic assay. H2OPPAH showed the potent antioxidant activity followed by Co(II) and Cu(II) complexes. On the other hand Ni(II) complex exhibited weak antioxidant activity using ABTS free radical and Erlich and strong erythrocyte hemolysis activity.

  1. Magnetic, high-field EPR studies and catalytic activity of Schiff base tetranuclear CuII2FeIII2 complexes obtained by direct synthesis.

    PubMed

    Nesterova, Oksana V; Chygorin, Eduard N; Kokozay, Vladimir N; Bon, Volodymyr V; Omelchenko, Irina V; Shishkin, Oleg V; Titiš, Ján; Bo?a, Roman; Pombeiro, Armando J L; Ozarowski, Andrew

    2013-12-28

    Two novel heterometallic complexes [Cu2Fe2(HL(1))2(H2L(1))2]·10DMSO (1) and [Cu2Fe2(HL(2))2(H2L(2))2]·2DMF (2) have been prepared using the open-air reaction of copper powder, iron(II) chloride and DMSO (1) or DMF (2) solutions of the polydentate Schiff base (H4L(1), 1; H4L(2), 2) formed in situ from salicylaldehyde (1) or 5-bromo-salicylaldehyde (2) and tris(hydroxymethyl)aminomethane. Crystallographic analysis revealed that both compounds are based on the centrosymmetric tetranuclear core {Cu(II)2Fe(III)2(?-O)6} where metal centres are joined by ?-O bridges from the deprotonated ligands forming a nonlinear chain-like arrangement. Variable-temperature (1.8-300 K) magnetic susceptibility measurements of 1 and 2 showed a decrease of the effective magnetic moment value at low temperature, indicative of antiferromagnetic coupling (JCu-Fe/hc = -10.2 cm(-1), JFe-Fe/hc = -10.5 cm(-1) in 1, JCu-Fe/hc = -10.5 cm(-1), JFe-Fe/hc = -8.93 cm(-1) in 2) between the magnetic centres in both compounds. They reveal an exceptionally high catalytic activity in the oxidation of cyclohexane with hydrogen peroxide under mild conditions, with the best observed yield/TON combined values of 36%/596 and 44%/1.1 × 10(3) for 1 and 2, respectively. PMID:24091798

  2. DNA interaction studies and evaluation of biological activity of homo- and hetero-trihalide mononuclear Cu(II) Schiff base complexes. Quantitative structure-activity relationships.

    PubMed

    Chaviara, A T; Kioseoglou, E E; Pantazaki, A A; Tsipis, A C; Karipidis, P A; Kyriakidis, D A; Bolos, C A

    2008-09-01

    A new series of mixed-ligand mono- or hetero-trihalide Cu(II) complexes of the type [Cu(dienXX)Y(YZ(2))], where dienXX=Schiff dibase of diethylenetriamine with 2-thiophene-carboxaldehyde (dienSS), 2-furaldehyde (dienOO) or 2-pyrrole-2-carboxaldehyde (dienNN), Y=Cl, Br and Z=Br, I was synthesized by the reaction of the precursors of the type [Cu(dienXX)Y]Y with iodine or bromine in 1:1 molar ratio. The distorted square pyramidal configuration of the new homo- and hetero-trihalide Cu(II) mononuclear complexes was identified by C, H, N, Cu analysis, spectroscopic methods (IR, UV-visible), molar conductivity and magnetic measurements. The basal plane consists of three nitrogen atoms of the Schiff base and one halogen (terminal) atom while another axially located trihalogen moiety occupies the fifth side of the square pyramid as a YZ(2) entity, adopting an almost linear configuration. The equilibrium geometry of these complexes was further corroborated by theoretical studies at the B3LYP/DGDZVP level. A series of quantum chemical descriptors (e.g. SOMO (singly occupied molecular orbital) LUMO (lowest occupied molecular orbital), SOMO and LUMO energies, SOMO-LUMO gap, dipole moment, polarizability, molar volume, etc.) have been utilized in order to deduce quantitative structure-activity relationships (QSARs). The effect of the new compounds on the single stranded (ss), double stranded (ds) and pDNA led either to the formation of a DNA-complex cationic adduct, or to its degradation, evidenced by DNA electrophoretic mobility and DNA interaction spectroscopic titration studies. Moreover, the antimicrobial activity of Cu(II) complexes against Gram(+) and Gram(-) bacteria can be attributed to the synergistic action of the dissociation species, namely the cationic [Cu(dienXX)Y](+) and anionic [YZ(2)](-) ones. Finally, de Novo linear regression analysis correlating the bioactivity of these complexes with their structural substituents has been carried out, leading to some interesting qualitative observations/conclusions. PMID:18584877

  3. Interactions of trivalent lanthanide cations with tetradentate Schiff bases: New lanthanide(III) complexes from (1 S,2 S, N 1 E, N 2 E)– N, N?-bis(pyridin-2-ylmethylene)cyclohexane-1,2-diamine

    Microsoft Academic Search

    Mantha Tsiouri; Nick Hadjiliadis; Taner Arslan; Benson M. Kariuki; John C. Plakatouras

    2006-01-01

    The novel lanthanide(III) complexes [Ln(NO3)3(MeOH)L] (Ln=La 1, Pr 2), and [Ln(NO3)3L]·MeOH (Ln=Sm 3, Gd 4) where L=N,N?-bis(pyridin-2-ylmethylene)cyclohexane-1,2-diamine, have been obtained by direct reaction of the Schiff base ligand and the corresponding hydrated lanthanide(III) nitrates in methanol. All complexes were characterized spectroscopically and thermogravimetrically. Complexes 2 and 3 were also characterized with crystallographic studies. In the molecular structure of 2, Pr(III)

  4. Synthesis and characterization of copper(II) azide complexes containing polyamines as co-ligands

    E-print Network

    Gao, Song

    anions and three nitrogen atoms of the diethylenetriamine ligand. Magnetic susceptibility measurement. Keywords: Azides; Polyamines; Copper(II) complexes; Crystal structures; Magnetic properties; Coordination polymers 1. Introduction Great efforts have been devoted to the study of transition metal azide complexes

  5. Highly selective thiocyanate poly(vinyl chloride) membrane electrode based on a cadmium-Schiff's base complex.

    PubMed

    Ganjali, M R; Poursaberi, T; Basiripour, F; Salavati-Niassari, M; Yousefi, M; Shamsipur, M

    2001-08-01

    A PVC membrane electrode based on a cadmium-salen (N,N'-bis-salicylidene-1,2-ethylenediamine) complex as an anion carrier is described. The electrode has an anti-Hofmeister selectivity sequence with a preference for thiocyanate at pH 1.5-11.0. It has a linear response to thiocyanate from 1.0 x 10(-6) to 1.0 x 10(-1) mol L(-1) with a slope of 59.1 +/- 0.2 mV per decade, and a detection limit of 7 x 10(-7) mol L(-1). This electrode has high selectivity for thiocyanate relative to many common organic and inorganic anions. The proposed sensor has a fast response time of approximately 15 s. It was applied to the determination of thiocyanate in a milk sample. PMID:11583093

  6. Synthesis aspects, structural, spectroscopic, antimicrobial and room temperature ferromagnetism of zinc iodide complex with Schiff based ligand

    NASA Astrophysics Data System (ADS)

    Shakila, K.; Kalainathan, S.

    2015-01-01

    In this paper, we report the successful growth of complex compound of zinc iodide with thiocarbamide by slow evaporation method. The single crystal XRD study reveals that the crystal belongs to monoclinic system with centrosymmetric space group and powder XRD analysis shows that the perfect crystalline nature of the crystal. The presence of functional group and element were confirmed from FT-IR and EDAX analysis. Optical absorbance of the grown crystal was studied by UV-Vis spectrophotometer. The optical constants were calculated from the optical absorbance data such as refractive index (n), extinction coefficient (K) and reflectance (R). The optical band gap (Eg) of thiocarbamide zinc iodide crystal is 4.22 eV. The magnetic properties of grown crystal have been determined by Vibrating Sample Magnetometry (VSM). Room temperature magnetization revealed a ferromagnetic behaviour for the grown crystal. The antibacterial and antifungal activities of the title compound were performed by well diffusion method and MIC method against the standard bacteria like Staphylococcus aureus, Escherichia coli, Klebsiella pneumonia and against fungus like Aspergillus niger, Rhizopus sps and Penicillium sps. Thermal behaviour of the crystal has been investigated using thermogravimetric analysis (TGA) and differential thermal analysis (DTA).

  7. Water-stable manganese(IV) complex of a N2O4-donor non-Schiff-base ligand: synthesis, structure, and multifrequency high-field electron paramagnetic resonance studies.

    PubMed

    Dolai, Malay; Amjad, Asma; Debnath, Mainak; van Tol, Johan; del Barco, Enrique; Ali, Mahammad

    2014-06-01

    A novel water-stable (t1/2 ? 6.8 days) mononuclear manganese(IV) complex of a hexacoordinating non-Schiff-base ligand (H4L) with N2O4-donor atoms has been synthesized and characterized crystallographically. High-frequency electron paramagnetic resonance experiments performed on a single crystal reveal a manganese(IV) ion with an S = 3/2 ground spin state that displays a large single-ion anisotropy, setting the record of mononuclear manganese(IV) complexes reported so far. In addition, spin-echo experiments reveal a spin-spin relaxation time T2 ? 500 ns. PMID:24824101

  8. Carbonic anhydrase inhibitors. Inhibition of cytosolic\\/tumor-associated carbonic anhydrase isozymes I, II, IX, and XII with Schiff’s bases incorporating chromone and aromatic sulfonamide moieties, and their zinc complexes

    Microsoft Academic Search

    Luca Puccetti; Giuseppe Fasolis; Daniela Vullo; Zahid H. Chohan; Andrea Scozzafava; Claudiu T. Supuran

    2005-01-01

    A series of Schiff’s bases was prepared by reaction of 3-formyl-chromone or 6-methyl-3-formyl-chromone with aromatic sulfonamides, such as sulfanilamide, homosulfanilamide, 4-aminoethyl-benzenesulfonamide, a pyrimidinyl-substituted sulfanilamide derivative, sulfaguanidine and 4-amino-6-trifluoromethyl-benzene-1,3-disulfonamide. The zinc complexes of these sulfonamides have also been obtained. The new derivatives and their Zn(II) complexes were investigated for the inhibition of four physiologically relevant isozymes of carbonic anhydrase (CA, EC

  9. Synthesis, characterisation and crystal structures of a few coordination complexes of nickel(II), cobalt(III) and zinc(II) with N?-[(2-pyridyl)methylene]salicyloylhydrazone Schiff base

    Microsoft Academic Search

    Brajagopal Samanta; Joy Chakraborty; Shyamapada Shit; Stuart R. Batten; Paul Jensen; Jason D. Masuda; Samiran Mitra

    2007-01-01

    Four new coordination complexes, NiII(L)2 (1), [CoIII(L)2]ClO4 (2), [Zn(HL)(L)]ClO4·H2O (3) and [Zn(L)2][Zn(L)(HL)]ClO4·7H2O (4) (where L is a monoanion of a Schiff base ligand, N?-[(2-pyridyl)methylene]salicyloylhydrazone (HL) with NNO tridentate donor set), have been synthesised and systematically characterised by elemental analysis, spectroscopic studies and room temperature magnetic susceptibility measurements. Single crystal X-ray diffraction analysis reveals that 1 is a neutral complex, while

  10. Syntheses, structures, and luminescence behavior of terephthalate bridged lead(II) complexes with tetradentate N-donor Schiff bases

    NASA Astrophysics Data System (ADS)

    Roy, Subhasis; Choubey, Somnath; Bhar, Kishalay; Khan, Sumitava; Mitra, Partha; Ghosh, Barindra Kumar

    2013-11-01

    Three dinuclear compounds of the types [Pb2(L1)2(?-tp)](ClO4)2 (1) and [Pb2(L2)2(?-tp)](ClO4/PF6)2 (2/3) [L1 = N,N'-(bis-(pyridin-2-yl)formylidene)-1,2-ethanediamine; L2 = N,N'-(bis-(pyridin-2-yl)benzylidene)-1,2-ethanediamine and tp = terephthalate dianion] have been synthesized using one-pot reactions of 2:2:1:2 M ratio of Pb(OAc)2?3H2O, L1/L2, piperidinium terephthalate (ptp) and appropriate counter anions in MeOH at room temperature. Compounds 1-3 are characterized on the basis of microanalytical, spectroscopic, thermal and other physicochemical results. X-ray structural analyses of 1-3 reveal each six-coordinated lead(II) center with PbN4O2 chromophore to be bound by four N atoms of L1 in 1 and L2 in 2 and 3 and connected through O atoms of a bis(bidentate) tp bridge. The arrangements of L1/L2 ligand and the tp dianion suggest a void around the metal center presumably occupied by a stereoactive lone pair of electrons that reflect a hemidirected coordination around the metal center. The complexes exhibit reasonable thermal stabilities. In solid states, L1, L2, ptp and 1 display intraligand ? ? ?* fluorescence and 1-3 show ligand-to-metal charge transfer at room temperature.

  11. Mono and BiNuclear Metal Complexes of Schiff-Base Hydrazone (ONN) Derived from o-Hydroxyacetophenone and 2Amino4Hydrazino6Methyl Pyrimidine

    Microsoft Academic Search

    Saied M. E. Khalil; H. S. Seleem; B. A. El-Shetary; M. Shebl

    2002-01-01

    A tridentate ONN donor Schiff-base hydrazone ligand, H2L, was synthesized by the condensation of 2-amino-4-hydrazino-6-methyl pyrimidine with o-hydroxyacetophenone. The structure of the ligand was elucidated by IR and H NMR spectra which indicated the presence of three different coordinating groups, the oxygen atom of the phenolic OH group, the nitrogen atom of the azomethine, C=N, group and one of the

  12. Antimicrobial, spectral, magnetic and thermal studies of Cu(II), Ni(II), Co(II), UO(2)(VI) and Fe(III) complexes of the Schiff base derived from oxalylhydrazide.

    PubMed

    Melha, Khlood Abou

    2008-04-01

    The Schiff base ligand, oxalyl [( 2 - hydroxybenzylidene) hydrazone] [corrected].H(2)L, and its Cu(II), Ni(II), Co(II), UO(2)(VI) and Fe(III) complexes were prepared and tested as antibacterial agents. The Schiff base acts as a dibasic tetra- or hexadentate ligand with metal cations in molar ratio 1:1 or 2:1 (M:L) to yield either mono- or binuclear complexes, respectively. The ligand and its metal complexes were characterized by elemental analyses, IR, (1)H NMR, Mass, and UV-Visible spectra and the magnetic moments and electrical conductance of the complexes were also determined. For binuclear complexes, the magnetic moments are quite low compared to the calculated value for two metal ions complexes and this shows antiferromagnetic interactions between the two adjacent metal ions. The ligand and its metal complexes were tested against a Gram + ve bacteria (Staphylococcus aureus), a Gram -ve bacteria (Escherichia coli), and a fungi (Candida albicans). The tested compounds exhibited high antibacterial activities. PMID:18343917

  13. From Planar Toward Tetrahedral Copper(Il) Complexes: Structural and Electron Paramagnetic Resonance Studies of Substituent Steric Effects in an Extended Class of Pyrrolate-Imine Ligands

    Microsoft Academic Search

    Chamika M. Wansapura; Choi Juyoung; Jason L. Simpson; Dennis Szymanski; Gareth R. Eaton; Sandra S. Eaton; Stephen Fox

    2003-01-01

    A series (1a-1h) of crystalline bis-pyrrolate-imine copper(II) complexes was isolated in good yield (typically 60-90%) by reaction of the Schiff base 2-N-(R)-pyrrolecarbaldimine (where R is an alkyl group of variable steric capacity) with a copper(II) salt and base in methanol or water. For new complexes 1f-1h, pyrrolate-imine coordination is inferred by loss of ?(N-H) and a shift (ca. 40 cm)

  14. Tuning Interchain Interactions in Two-Dimensional Networks of Mn(III) Schiff-Base Complexes and Dicarboxylic Acids by Varying the Linker.

    PubMed

    Aono, Yoshitaka; Yoshida, Hiroki; Katoh, Keiichi; Breedlove, Brian K; Kagesawa, Koichi; Yamashita, Masahiro

    2015-07-20

    Two-dimensional (2D) coordination polymers consisting of Mn(III) Schiff-base complexes and dicarboxylic acids, [{Mn(salen)}4(L1)](PF6)2·(CH3OH)2 (C4; H2L1 = adipid acid) and [{Mn(salen)}4(L2)](PF6)2·(CH3OH)4 (C4'; H2L2 = E,E-1,3-butadiene-1,4-dicarboxylic acid) (salen(2-) = N,N'-(ethylene)bis(salicylideneiminato), were synthesized by using a one-pot reaction and characterized by using single-crystal X-ray crystallographic analysis. One-dimensional (1D) chains composed of Mn(salen) dimers, [Mn2], bridged by carboxylato ligands (-[Mn2]-OCO--[Mn2]-), were linked by dicarboxylato ligands with n-butyl (-C4H8-) (C4) and butadienyl aliphatic groups (-C4H4-) (C4'). From static magnetic measurements on both C4 and C4', there were ferromagnetic interactions between the Mn(III) ions through the phenoxo oxygen atoms of the salen(2-), and antiferromagnetic interactions between the Mn(III) ions through carboxylato ligands (-OCO-). As a result, weak ferromagnetism occurred because of the zigzag-shaped chain structure of C4 and C4', and magnetic anisotropy for Mn(salen). In the magnetization curves for C4', weak interchain interactions (Jlinker) occurred through the ?-conjugated butadienyl linkers in C4', which C4 did not have. In other words, changing from saturated to unsaturated aliphatic groups in the dicarboxylic acid linkers resulted in weak interactions between 1D-magnetic chain moieties. Therefore, in the case of only C4', antiferromagnetic phase transition appeared at 2.3 K. Both coordination polymers exhibited slow relaxation of the magnetizations, which originated from SCM moieties, because C4 and C4' showed magnetic correlations. It is noteworthy that alternating current (ac) susceptibilities for C4' are frequency-dependent around the Néel temperature. From analysis of the ac susceptibilities for C4, ? (dispersion coefficient of the relaxation of magnetization) varied linearly with 1/T. This signifies that C4 behaved as an SCM with a single relaxation process. On the other hand, in ? versus 1/T plots for C4', an inflection point was observed at the Néel temperature, indicating that Jlinkers had an effect on the distribution of the relaxation times. Moreover, the inflection point for C4' disappeared when a dc magnetic field was applied. This is the first report showing a direct correlation between an antiferromagnetic phase transition and slow magnetic relaxation. PMID:26151757

  15. Synthesis and spectroscopic studies of homo-binuclear, alkoxo bridged homo- and hetero-tetranuclear metal complexes of a bis-N2O4 Schiff base ligand derived from ethanolamine and macroacyclic tetranaphthaldehyde.

    PubMed

    Karao?lu, Kaan; Baran, Talat; De?irmencio?lu, Ismail; Serbest, Kerim

    2011-09-01

    Three new homo-binuclear Ni(II), Cu(II), Zn(II) complexes (2-4), homo-tetranuclear Cu(II) complex (5), and hetero-tetranuclear Cu(II)-Ni(II) complex (6) of a macroacyclic potentially bis-hexadentate N2O4 Schiff base have been synthesized. The imino-alcohol ligand, H4L was obtained by the condensation of ethanolamine with 2,2'-[2,3-bis(1-formyl-2-naphthyloxymethyl)-but-2-ene-1,4-diyldioxy]bis(naphthalene-1-carbaldehyde). The structures of both the Schiff base and its complexes have been proposed by elemental analyses, spectroscopic data i.e. IR, 1H and 13C NMR, UV-vis, electrospray ionisation mass spectra, molar conductivities and magnetic susceptibility measurements. The ligand has two similar compartments to bind first primary two metal ions, and acts bi- or tetra-negative, bis-tetradentate forming five membered chelate ring. However, secondary two metal ions (either Cu2+ or Ni2+) are ligated with dianionic oxygen atoms of the alcohol groups and are linked to the 1,10-phenanthroline-nitrogen atoms in the tetranuclear complexes (5 and 6). PMID:21550297

  16. Synthesis and spectroscopic studies of homo-binuclear, alkoxo bridged homo- and hetero-tetranuclear metal complexes of a bis-N 2O 4 Schiff base ligand derived from ethanolamine and macroacyclic tetranaphthaldehyde

    NASA Astrophysics Data System (ADS)

    Karao?lu, Kaan; Baran, Talat; De?irmencio?lu, ?smail; Serbest, Kerim

    2011-09-01

    Three new homo-binuclear Ni(II), Cu(II), Zn(II) complexes ( 2-4), homo-tetranuclear Cu(II) complex ( 5), and hetero-tetranuclear Cu(II)-Ni(II) complex ( 6) of a macroacyclic potentially bis-hexadentate N 2O 4 Schiff base have been synthesized. The imino-alcohol ligand, H 4L was obtained by the condensation of ethanolamine with 2,2'-[2,3-bis(1-formyl-2-naphthyloxymethyl)-but-2-ene-1,4-diyldioxy]bis(naphthalene-1-carbaldehyde). The structures of both the Schiff base and its complexes have been proposed by elemental analyses, spectroscopic data i.e. IR, 1H and 13C NMR, UV-vis, electrospray ionisation mass spectra, molar conductivities and magnetic susceptibility measurements. The ligand has two similar compartments to bind first primary two metal ions, and acts bi- or tetra-negative, bis-tetradentate forming five membered chelate ring. However, secondary two metal ions (either Cu 2+ or Ni 2+) are ligated with dianionic oxygen atoms of the alcohol groups and are linked to the 1,10-phenanthroline-nitrogen atoms in the tetranuclear complexes ( 5 and 6).

  17. Ferromagnetic coupling in copper(II) [2 × 2] grid-like complexes.

    PubMed

    Madalan, Augustin M; Cao, Xiao-Yu; Rogez, Guillaume; Lehn, Jean-Marie

    2014-05-01

    Two copper(II) [2 × 2] grid-like complexes were synthesized and structurally characterized. Investigation of the magnetic properties showed for both the occurrence of intramolecular ferromagnetic interactions. PMID:24749519

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

    SciTech Connect

    Mahjoub, Omima Abdalla; Farina, Yang [School of Chemical Sciences and Food Technology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor (Malaysia)

    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.

  19. Synthesis, spectral characterization, DNA binding studies and antimicrobial activity of Co(II), Ni(II), Zn(II), Fe(III) and VO(IV) complexes with 4-aminoantipyrine Schiff base of ortho-vanillin.

    PubMed

    Anupama, B; Sunita, M; Shiva Leela, D; Ushaiah, B; Gyana Kumari, C

    2014-07-01

    A series of transition metal complexes of Co(II), Ni(II), Zn(II), Fe(III) and VO(IV) have been synthesized involving the Schiff base, 2,3-dimethyl-1-phenyl-4-(2-hydroxy-3-methoxy benzylideneamino)-pyrazol-5-one(L), obtained by condensation of 4-aminoantipyrine with 3-methoxy salicylaldehyde. Structural features were obtained from their FT-IR, UV-vis, NMR, ESI Mass, elemental analysis, magnetic moments, molar conductivity and thermal analysis studies. The Schiff base acts as a monovalent bidentate ligand, coordinating through the azomethine nitrogen and phenolic oxygen atom. Based on elemental and spectral studies six coordinated geometry is assigned to Co(II), Ni(II), Fe(III) and VO(IV) complexes and four coordinated geometry is assigned to Zn(II) complex. The interaction of metal complexes with Calf thymus DNA were carried out by UV-VIS titrations, fluorescence spectroscopy and viscosity measurements. The binding constants (K(b)) of the complexes were determined as 5?×?10(5) M(-1) for Co(II) complex, 1.33?×?10(4) M(-1) for Ni(II) complex, 3.33?×?10(5) M(-1) for Zn(II) complex, 1.25?×?10(5) M(-1) for Fe(III) complex and 8?×?10(5) M(-1) for VO(IV) complex. Quenching studies of the complexes indicate that these complexes strongly bind to DNA. Viscosity measurements indicate the binding mode of complexes with CT DNA by intercalation through groove. The ligand and it's metal complexes were screened for their antimicrobial activity against bacteria. The results showed the metal complexes to be biologically active, while the ligand to be inactive. PMID:24781660

  20. Chiral vanadium(V) complexes with 2-aminoglucose Schiff-base ligands and their solution configurations: synthesis, structures, and DFT calculations.

    PubMed

    Mohammadnezhad, Gholamhossein; Böhme, Michael; Geibig, Daniel; Burkhardt, Anja; Görls, Helmar; Plass, Winfried

    2013-09-01

    The sugar-modified Schiff-base ligands derived from benzyl 2-deoxy-2-salicylideneamino-?-D-glucopyranoside (H2L(5-Br) and H2L(3-OMe)) were used to prepare the chiral oxidovanadium(V) complexes [VO(L(5-Br))(OMe)] (1) and [VO(L(3-OMe))(OMe)] (2) which can be isolated from a methanol solution as the six-coordinate complexes with an additional methanol ligand [VO(L(5-Br))(OMe)(MeOH)] (1-MeOH) and [VO(L(3-OMe))(OMe) (MeOH)] (2-MeOH). Both complexes crystallize in the orthorhombic space group P2(1)2(1)2(1) together with two solvent molecules of methanol as 1-MeOH·2MeOH and 1-MeOH·2MeOH. In both crystal structures, only diastereomers with A configuration at the chiral vanadium centre (OC-6-24-A) are observed which corresponds to an cis configuration of the oxido group at the vanadium centre and the benzyl group at the anomeric carbon of the sugar backbone. Upon recrystallization of 2-MeOH from chloroform, the five-coordinate complex 2 was obtained which crystallizes in the monoclinic space group P2(1) with one co-crystallized chloroform molecule (2·CHCl3). For the chiral vanadium centre in 2·CHCl3, a C configuration (SPY-5-43-C) is observed which corresponds to an trans structure as far as the orientations of the oxido and benzyl groups are concerned. (1)H and (51)V NMR spectra of 1 and 2 indicate the presence of two diastereomers in solution. Their absolute configurations can be assigned based on the magnetic anisotropy effect of the oxidovanadium group. This effect leads to significant differences for the (1)H NMR chemical shifts of the H-2 (1.1 ppm) and H-3 protons (0.3 ppm) of the glucose backbone of the two diastereomers, with the downfield shift observed for the H-2 proton of the C-configured and the H-3 proton of the A-configured diastereomer at the vanadium centre. For 1 and 2 the difference between the (51)V NMR chemical shifts of the two diastereomers is 30 and 28 ppm, respectively. Also in the (13)C NMR significant chemical shift differences between the two diastereomers are observed for the carbon atoms C2 (2 ppm) and C3 (4 ppm). DFT calculations of the NMR chemical shift parameters have been performed which are in good agreement with the experimental data. Moreover, the isomerization mechanism between the diastereomers is analysed on the basis of DFT calculations which indicate the required presence of methanol molecules as protic donors. PMID:23760018

  1. Synthesis, spectral characterization, solution equilibria, in vitro antibacterial and cytotoxic activities of Cu(II), Ni(II), Mn(II), Co(II) and Zn(II) complexes with Schiff base derived from 5-bromosalicylaldehyde and 2-aminomethylthiophene

    NASA Astrophysics Data System (ADS)

    El-Sherif, Ahmed A.; Eldebss, Taha M. A.

    2011-09-01

    Schiff base namely 2-aminomethylthiophenyl-4-bromosalicylaldehyde (ATS)(4-bromo-2-(thiophen-2-yl-imino)methylphenol) and its metal complexes have been synthesized and characterized by elemental analyses, IR, 1H NMR, solid reflectance, magnetic moment, molar conductance, mass spectra, ESR and thermal analysis (TGA). The analytical data of the complexes show the formation of 1:2 [M:L] ratio of the formula [ML 2], where M represents Ni(II), Zn(II) and Cu(II) ions, while L represents the deprotonated Schiff base. IR spectra show that ATS is coordinated to the metal ions in a bidentate manner through azomethine-N and phenolic-oxygen groups. The ligand and their metal chelates have been screened for their antimicrobial activities using the disc diffusion method against the selected bacteria. A cytotoxicity of the compounds against colon (HCT116) and larynx (HEP2) cancer cells have been studied. Protonation constants of (ATS) ligand and stability constants of its Cu 2+, Co 2+, Mn 2+, Zn 2+ and Ni 2+ complexes were determined by potentiometric titration method in 50% (v/v) DMSO-water solution at ionic strength of 0.1 M NaNO 3.

  2. Synthesis, Characterization, and Antitumor Activity of Some Metal Complexes with Schiff Bases Derived from 9-Fluorenone as a Polycyclic Aromatic Compound

    Microsoft Academic Search

    Nabil S. Youssef; Eman A. El Zahany; Manal M. Anwar; Sohair A. Hassan

    2008-01-01

    New bidendate Schiff base ligands HL [(9H-fluorene-9-ylidene)-thiosemicarbazide], HL [(9H-fluorene-9-ylidene)semicarbazide] and L [N ,N -di(9H-fluorene-9-ylidene)ethan-1,2-diamine] derived from the condensation of thiosemicarbazide, semicarbazide, and ethylenediamine with 9-fluorenone as polycyclic aromatic compound (PAC). Ag(I), Cu(II), VO(IV), La(III), and Zn(II) of the ligands HL, HL, and L have been prepared and characterized by conductance and magnetic measurements, and electronic, infrared, and H NMR spectral

  3. Structural, spectral and biological studies of binuclear tetradentate metal complexes of N 3O Schiff base ligand synthesized from 4,6-diacetylresorcinol and diethylenetriamine

    Microsoft Academic Search

    Adel A. A. Emara

    2010-01-01

    The binuclear Schiff base, H2L, ligand was synthesized by reaction of 4,6-diacetylresorcinol with diethylenetriamine in the molar ratio 1:2. The coordination behavior of the H2L towards Cu(II), Ni(II), Co(II), Zn(II), Fe(III), Cr(III), VO(IV) and UO2(VI) ions has been investigated. The elemental analyses, magnetic moments, thermal studies and IR, electronic, 1H NMR, ESR and mass spectra were used to characterize the

  4. Copper(I) and copper(II) complexes of an ethylene cross-bridged cyclam

    E-print Network

    Hubin, Tim

    Copper(I) and copper(II) complexes of an ethylene cross-bridged cyclam Timothy J. Hubin,a Nathaniel and crystal structures of (4,11-dibenzyl- 1,4,8,11-tetraazabicyclo[6.6.2]hexadecane- 4 N)copper(I) hexa)- copper(II) bis(hexa¯uorophosphate), [Cu(C2H3N)(C26H38- N4)](PF6)2, are described. The CuI ion

  5. Crystal structures and catalytic performance of three new methoxy substituted salen type nickel(II) Schiff base complexes derived from meso-1,2-diphenyl-1,2-ethylenediamine

    NASA Astrophysics Data System (ADS)

    Ghaffari, Abolfazl; Behzad, Mahdi; Pooyan, Mahsa; Amiri Rudbari, Hadi; Bruno, Giuseppe

    2014-04-01

    Three new nickel(II) complexes of a series of methoxy substituted salen type Schiff base ligands were synthesized and characterized by IR, UV-Vis and 1H NMR spectroscopy and elemental analysis. The ligands were synthesized from the condensation of meso-1,2-diphenyl-1,2-ethylenediamine with n-methoxysalicylaldehyde (n = 3, 4 and 5). Crystal structures of these complexes were determined. Electrochemical behavior of the complexes was studied by means of cyclic voltammetry in DMSO solutions. Catalytic performance of the complexes was studied in the epoxidation of cyclooctene using tert-butylhydroperoxide (TBHP) as oxidant under various conditions to find the optimum operating parameters. Low catalytic activity with moderate epoxide selectivity was observed in in-solvent conditions but in the solvent-free conditions, enhanced catalytic activity with high epoxide selectivity was achieved.

  6. Design, spectral characterization, thermal, DFT studies and anticancer cell line activities of Co(II), Ni(II) and Cu(II) complexes of Schiff bases derived from 4-amino-5-(pyridin-4-yl)-4H-1,2,4-triazole-3-thiol

    NASA Astrophysics Data System (ADS)

    Tyagi, Prateek; Chandra, Sulekh; Saraswat, B. S.; Yadav, Deepak

    2015-06-01

    A series of two biologically active Schiff base ligands L1, L2 have been synthesized in equimolar reaction of 4-amino-5-(pyridin-4-yl)-4H-1,2,4-triazole-3-thiol with thiophene-2-carbaldehyde and furan-2-carbaldehyde. The synthesized Schiff bases were used for complexation with different metal ions like Co(II), Ni(II) and Cu(II) by using a molar ratio of ligand: metal as 1:1 and 2:1. The characterization of Schiff bases and metal complexes was done by 1H NMR, UV-Vis, TGA, IR, mass spectrometry and molar conductivity studies. The in DFT studies the geometries of Schiff bases and metal complexes were fully optimized with respect to the energy using the 6-31+g(d,p) basis set. On the basis of the spectral studies an octahedral geometry has been assigned for Co(II), Ni(II) and Cu(II) complexes. The effect of these complexes on proliferation of human breast cancer cell line (MCF-7) and human hepatocellular liver carcinoma cell line (Hep-G2) were studied and compared with those of free ligand. The anticancer cell line results reveal that all metal complexes show moderate to significant % cytotoxicity on cell line HepG2 and MCF-7.

  7. Design, spectral characterization, thermal, DFT studies and anticancer cell line activities of Co(II), Ni(II) and Cu(II) complexes of Schiff bases derived from 4-amino-5-(pyridin-4-yl)-4H-1,2,4-triazole-3-thiol.

    PubMed

    Tyagi, Prateek; Chandra, Sulekh; Saraswat, B S; Yadav, Deepak

    2015-06-15

    A series of two biologically active Schiff base ligands L(1), L(2) have been synthesized in equimolar reaction of 4-amino-5-(pyridin-4-yl)-4H-1,2,4-triazole-3-thiol with thiophene-2-carbaldehyde and furan-2-carbaldehyde. The synthesized Schiff bases were used for complexation with different metal ions like Co(II), Ni(II) and Cu(II) by using a molar ratio of ligand: metal as 1:1 and 2:1. The characterization of Schiff bases and metal complexes was done by (1)H NMR, UV-Vis, TGA, IR, mass spectrometry and molar conductivity studies. The in DFT studies the geometries of Schiff bases and metal complexes were fully optimized with respect to the energy using the 6-31+g(d,p) basis set. On the basis of the spectral studies an octahedral geometry has been assigned for Co(II), Ni(II) and Cu(II) complexes. The effect of these complexes on proliferation of human breast cancer cell line (MCF-7) and human hepatocellular liver carcinoma cell line (Hep-G2) were studied and compared with those of free ligand. The anticancer cell line results reveal that all metal complexes show moderate to significant % cytotoxicity on cell line HepG2 and MCF-7. PMID:25770965

  8. Electronic structure and spectroscopic properties of mononuclear manganese(III) Schiff base complexes: a systematic study on [Mn(acen)X] complexes by EPR, UV/vis, and MCD spectroscopy (X = Hal, NCS).

    PubMed

    Westphal, Anne; Klinkebiel, Arne; Berends, Hans-Martin; Broda, Henning; Kurz, Philipp; Tuczek, Felix

    2013-03-01

    The manganese(III) Schiff base complexes [Mn(acen)X] (H2acen: N,N'-ethylenebis(acetylacetone)imine, X: I(-), Br(-), Cl(-), NCS(-)) are considered as model systems for a combined study of the electronic structure using vibrational, UV/vis absorption, parallel-mode electron paramagnetic resonance (EPR) and low-temperature magnetic circular dichroism (MCD) spectroscopy. By variation of the co-ligand X, the influence of the axial ligand field within a given square-pyramidal coordination geometry on the UV/vis, EPR, and MCD spectra of the title compounds is investigated. Between 25000 and 35000 cm(-1), the low-temperature MCD spectra are dominated by two very intense, oppositely signed pseudo-A terms, referred to as "double pseudo-A terms", which change their signs within the [Mn(acen)X] series dependent on the axial ligand X. Based on molecular orbital (MO) and symmetry considerations, these features are assigned to ?(n.b.)(s, a) ? yz, z(2) ligand-to-metal charge transfer transitions. The individual MCD signs are directly determined from the calculated MOs of the [Mn(acen)X] complexes. The observed sign change is explained by an inversion of symmetry among the ?(n.b.)(s, a) donor orbitals which leads to an interchange of the positive and negative pseudo-A terms constituting the "double pseudo-A term". PMID:23410227

  9. Synthesis and Characterization of New Schiff Bases Derived from N (1)-Substituted Isatin with Dithiooxamide and Their Co(II), Ni(II), Cu(II), Pd(II), and Pt(IV) Complexes

    PubMed Central

    Abdul-Ghani, Ahlam J.; Khaleel, Asmaa M. N.

    2009-01-01

    Three new Schiff bases of N-substituted isatin LI, LII, and LIII = Schiff base of N-acetylisatin, N-benzylisatin, and N-benzoylisatin, respectively, and their metal complexes C1a,b = [Co2(LI)2Cl3]Cl, C2 = [Ni(LI)2Cl2]0.4BuOH, C3 = [CuLICl(H2O)]Cl ? 0.5BuOH, C4 = [Pd(LI)2Cl]Cl, C5 = [Pt(L1)2Cl2]Cl2 ? 1.8EtOH.H2O, C6a = [CoLIICl]Cl ? 0.4H2O ? 0.3DMSO, C6b = [CoLIICl]Cl ? 0.3H2O ? 0.1BuOH, C7 = [NiLIICl2], C8 = [CuLII]Cl2 ? H2O , C9 = [Pd(LII)2]Cl2, C10 = [Pt(LII)2.5Cl]Cl3, C11a = [Co(LIII)]C12 ? H2O, C11b = [Co(LIII)]Cl2 ? 0.2H2O, and C12 = [Ni(LIII)2]Cl2, C13 = [Ni(LIII)2]Cl2 were reported. The complexes were characterized by elemental analyses, metal and chloride content, spectroscopic methods, magnetic moments, conductivity measurements, and thermal studies. Some of these compounds were tested as antibacterial and antifungal agents against Staphylococcus aureus, Proteus vulgaris, Candida albicans, and Aspergillus niger. PMID:19865487

  10. EXAFS Study of the Inner Shell Structure in Copper(II) Complexes

    E-print Network

    Frenkel, Anatoly

    EXAFS Study of the Inner Shell Structure in Copper(II) Complexes with Humic Substances G R E G O R spectroscopy (EXAFS). This method is highly sensitive to the local structure around the target (e.g., Cu2 complexes. The quality of the fit of the EXAFS data was tested using modelsystems

  11. Complexation between the fungicide tebuconazole and copper(II) probed by electrospray ionization mass spectrometry.

    PubMed

    Dytrtová, Jana Jaklová; Jakl, Michal; Schröder, Detlef; ?adková, Eva; Komárek, Michael

    2011-04-30

    Electrospray ionization mass spectrometry (ESI-MS) is used to probe the complex formation between tebuconazole (1) and copper(II) salts, which both are commonly used fungicides in agriculture. Experiments with model solutions containing 1 and CuCl(2) reveal the initial formation of the copper(II) species [(1)CuCl](+) and [(1)(2)CuCl](+) which undergo reduction to the corresponding copper(I) ions [(1)Cu](+) and [(1)(2)Cu](+) under more drastic ionization conditions in the ESI source. In additional experiments, copper/tebuconazole complexes were also detected in samples made from soil solutions of various origin and different amount of mineralization. The direct sampling of such solutions via ESI-MS is thus potentially useful for understanding of the interactions between copper(II) salts and tebuconazole in environmental samples. PMID:21452380

  12. Novel heterometallic Schiff base complexes featuring unusual tetranuclear {Co(III)2Fe(III)2(?-O)6} and octanuclear {Co(III)4Fe(III)4(?-O)14} cores: direct synthesis, crystal structures, and magnetic properties.

    PubMed

    Chygorin, Eduard N; Nesterova, Oksana V; Rusanova, Julia A; Kokozay, Vladimir N; Bon, Volodymyr V; Bo?a, Roman; Ozarowski, Andrew

    2012-01-01

    A one-pot reactions of cobalt powder with iron(II) chloride in dimethylformamide (DMF; 1) or dimethyl sulfoxide (DMSO; 2) solutions of polydentate salicylaldimine Schiff base ligands (H(2)L(1), 1; H(4)L(2), 2) based on 2-aminobenzyl alcohol (1) or tris(hydroxymethyl)aminomethane (2), formed in situ, yielded two novel heterometallic complexes, [Co(III)(2)Fe(III)(2)(L(1))(6)]·4DMF (1) and [Co(III)(4)Fe(III)(4)(HL(2))(8)(DMSO)(2)]·18DMSO (2). Crystallographic investigations revealed that the molecular structure of 1 is based on a tetranuclear core, {Co(III)(2)Fe(III)(2)(?-O)(6)}, with a chainlike metal arrangement, while the structure of 2 represents the first example of a heterometallic octanuclear core, {Co(III)(4)Fe(III)(4)(?-O)(14)}, with a quite rare manner of metal organization, formed by two pairs of {CoFe(HL(2))(2)} and {CoFe(HL(2))(2)(DMSO)} moieties, which are joined by O bridges of the Schiff base ligands. Variable-temperature (1.8-300 K) magnetic susceptibility measurements showed a decrease of the ?(B) value at low temperature, indicative of antiferromagnetic coupling (J/hc = -32 cm(-1) in 1; J/hc = -20 cm(-1) in 2) between the Fe(III) magnetic centers in both compounds. For 2, three J constants between Fe(III) centers were assumed to be identical. High-frequency electron paramagnetic resonance spectra allowed one to find spin Hamiltonian parameters in the coupled-spin triplet and quintet states of 1 and estimate them in 2. The "outer" and "inner" Fe atoms in 2 appeared separately in the Mössbauer spectra. PMID:22129107

  13. Metal Complexes: Preparation, Magnetic, Spectral, and Biocidal Studies of Some Mixed?Ligand Complexes with Schiff Bases Containing NO and NN Donor Atoms

    Microsoft Academic Search

    Prakash P. Dholakiya; M. N. Patel

    2004-01-01

    Metal complexes of the types [M(SB)2acphen] and [M(SB)2acphen] where M = Mn(II), Co(II), Ni(II), Cu(II), and Cd(II); HSB = 5?chlorosalicylidene?p?anisidine and HSB = 5?bromosalicylidene?p?anisidine have been prepared and characterized. Magnetic susceptibility measurements, elemental analyses, electro?nic, and infrared spectral data suggest six?coordinated octahedral structures for these complexes. The mixed?ligand complexes show higher activity against Saccharomyces cereuisae, Salmonella typhi, Fasarium oxysporum, and Lasiodiplodia theobromae as compared to the

  14. Electron spin resonance and magnetic studies on some copper(II) azobarbituric and azothiobarbituric acid complexes.

    PubMed

    Masoud, M S; Khalil, E A; Hafez, A M; El-Husseiny, A F

    2005-03-01

    Electron spin resonance and magnetic susceptibility on some copper(II) complexes prepared from phenylazobarbituric and phenylazothiobarbituric acid compounds containing 2,5-dichloro and 2,5-dimethyl groups were discussed. The thio complexes exist in dimer-monomer mixture. The corresponding copper(II) complexes of the oxygen homologous failed to exhibit association. Singlet-triplet separation values equal to -321 and -263 cm(-1) for the 2,5-dimethyl and 2,5-dichloro complexes, respectively, of the thio series. An empirical measure of the amount of tetrahedral deformation based on the values of g||/A|| assigned the square-planar geometry of the dimethyl-oxygen complex while the other complexes are with tetrahedral planar geometries. The effect of temperature on the ESR data was discussed. The diamagnetic properties of the complexes derived from 2,5-dichloro and 2,5-dimethyl thiobarbituric acid suggested the formation of Cu(I) complexes. PMID:15683807

  15. Direct Nitric Oxide Detection in Aqueous Solution by Copper(II) Fluorescein Complexes

    E-print Network

    Baik, Mu-Hyun

    Direct Nitric Oxide Detection in Aqueous Solution by Copper(II) Fluorescein Complexes Mi Hee Lim nitrogen atoms of the FLn ligands most likely bind to Cu(II). Introduction of nitric oxide (NO) to pH 7-time detection of nitric oxide production in living cells. Introduction Nitric oxide (NO) is produced

  16. Coordination chemistry and bioactivity of Ni 2+, Cu 2+, Cd 2+ and Zn 2+ complexes containing bidentate Schiff bases derived from S-benzyldithiocarbazate and the X-ray crystal structure of bis[ S-benzyl-?- N-(5-methyl-2-furylmethylene)dithiocarbazato]cadmium(II)

    Microsoft Academic Search

    M. T. H Tarafder; Khoo Teng Jin; Karen A Crouse; A. M Ali; B. M Yamin; H.-K Fun

    2002-01-01

    New bidentate isomeric NS and NS? Schiff bases were derived from the condensation of S-benzyldithiocarbazate (SBDTC) with 5-methyl-2-furyldehyde and 2-furyl-methylketone. Reaction of NS ligand with Ni(II), Cu(II), Cd(II) and Zn(II) salts gave solid complexes. Only the Ni(II) complex of the NS? ligand was isolated. All complexes were characterized by a variety of physico-chemical techniques, viz. elemental analyses, molar conductivity, i.r.

  17. 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

    Microsoft Academic Search

    Adel A. A. Emara; Akila A. Saleh; Omima M. I. Adly

    2007-01-01

    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 O2N or N2O 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 H4La and H2Lb, respectively. The structures

  18. High-energy complex copper(II) perchlorate with 1,5-pentamethylenetetrasole as ligand

    Microsoft Academic Search

    I. V. Bachurina; M. A. Ilyushin; I. V. Tselinskii; Yu. A. Gruzdev

    2007-01-01

    Possibility of obtaining an energy-saturated metal complex, copper tetrakis[cyclopentamethylenetetrasol] perchlorate, was\\u000a studied by reacting copper(II) perchlorate hexahydrate with cyclopentamethylenetetrazol. The composition and structure of\\u000a the complex were confirmed by elemental analysis and UV, IR, 1H NMR, and ESR spectroscopies. The thermal decomposition of the metal complex synthesized was analyzed and its explosive characteristics\\u000a and combustion law, as well as the

  19. Synthesis and structural features of U VI and V IV chelate complexes with (hhmmbH)Cl·H 2O [hhmmb = {3-hydroxyl-5-(hydroxymethyl)-2-methylpyridine-4-yl-methylene}benzohydrazide], a new Schiff base ligand derived from vitamin B6

    NASA Astrophysics Data System (ADS)

    Back, Davi Fernando; Ballin, Marco Aurélio; de Oliveira, Gelson Manzoni

    2009-10-01

    The Schiff base ligand {3-hydroxyl-5-(hydroxymethyl)-2-methylpyridine-4-yl-methylene}benzohydrazide hydrochloride monohydrated {(hhmmbH)Cl·H 2O} ( 1) was prepared by reaction of pyridoxine hydrochloride with benzoic acid hydrazide. The reaction of 1 with [VO(acac) 2] and triethylamine yields the neutral vanadium IV complex [VO 2(hhmmb)]·Py ( 2), with a distorted quadratic pyramidal configuration. The Schiff base 1 reacts also with UO 2(NO 3) 2·6H 2O and triethylamine under deprotonation giving the uranium VI cationic complexes [UO 2(hhmmb)(H 2O)Cl] + ( 3) and [UO 2(hhmmb)(CH 3OH)Cl] + ( 4), both showing the classical pentagonal bipyrimidal geometry of UO22+ complexes. The structural features of all compounds are discussed.

  20. Synthesis and mesomorphism of new chiral imines and copper(II) complexes

    NASA Astrophysics Data System (ADS)

    Paul, Manoj K.; Kalita, Gayatri; Laskar, Atiqur Rahman; Choudhury, Trirup D.; Rao, Nandiraju V. S.

    2013-05-01

    The synthesis, characterization and mesomorphic properties of a series of N-(2-hydroxy-4-n-alkyloxybenzylidene) 4'-amino-2-methylbutylcinnamate and their copper(II) complexes are reported. The imines exhibited smectic A (SmA) and chiral smectic C (SmC*) phases while their copper(II) complexes displayed SmA-SmC phase variant. The compounds have been characterized by elemental analysis and spectroscopic studies. The phase transition temperatures were detected by differential scanning calorimetry (DSC) analysis and the phases are confirmed by polarizing optical microscopy (POM). The chiral phase (SmC*) of the ligand disappeared on complexation. The unwinding of the helical superstructure of SmC* phase under the influence of electric field and the observed optical textures of SmC* phase are also discussed.

  1. Synthesis, crystal structures, magnetic properties and catecholase activity of double phenoxido-bridged penta-coordinated dinuclear nickel(II) complexes derived from reduced Schiff-base ligands: mechanistic inference of catecholase activity.

    PubMed

    Biswas, Apurba; Das, Lakshmi Kanta; Drew, Michael G B; Aromí, Guillem; Gamez, Patrick; Ghosh, Ashutosh

    2012-08-01

    Three double phenoxido-bridged dinuclear nickel(II) complexes, namely [Ni(2)(L(1))(2)(NCS)(2)] (1), [Ni(2)(L(2))(2)(NCS)(2)] (2), and [Ni(2)(L(3))(2)(NCS)(2)] (3) have been synthesized using the reduced tridentate Schiff-base ligands 2-[1-(3-methylamino-propylamino)-ethyl]-phenol (HL(1)), 2-[1-(2-dimethylamino-ethylamino)-ethyl]-phenol (HL(2)), and 2-[1-(3-dimethylamino-propylamino)-ethyl]-phenol (HL(3)), respectively. The coordination compounds have been characterized by X-ray structural analyses, magnetic-susceptibility measurements, and various spectroscopic methods. In all complexes, the nickel(II) ions are penta-coordinated in a square-pyramidal environment, which is severely distorted in the case of 1 (Addison parameter ? = 0.47) and 3 (? = 0.29), while it is almost perfect for 2 (? = 0.03). This arrangement leads to relatively strong antiferromagnetic interactions between the Ni(II) (S = 1) metal centers as mediated by double phenoxido bridges (with J values of -23.32 (1), -35.45 (2), and -34.02 (3) cm(3) K mol(-1), in the convention H = -2JS(1)S(2)). The catalytic activity of these Ni compounds has been investigated for the aerial oxidation of 3,5-di-tert-butylcatechol. Kinetic data analysis following Michaelis-Menten treatment reveals that the catecholase activity of the complexes is influenced by the flexibility of the ligand and also by the geometry around the metal ion. Electrospray ionization mass spectroscopy (ESI-MS) studies (in the positive mode) have been performed for all the coordination compounds in the presence of 3,5-DTBC to characterize potential complex-substrate intermediates. The mass-spectrometry data, corroborated by electron paramagnetic resonance (EPR) measurements, suggest that the metal centers are involved in the catecholase activity exhibited by the complexes. PMID:22759340

  2. ((2-Hydroxynapthalen-1-yl)methylene)aniline derived Schiff base adducts of MTO: Synthesis and catalytic application

    Microsoft Academic Search

    Alejandro Capapé; Ming-Dong Zhou; Shu-Liang Zang; Fritz E. Kühn

    2008-01-01

    Equimolar reactions of the derivatives of ((2-hydroxynapthalen-1-yl)methylene)aniline with methyltrioxorhenium (MTO) lead to complexes 1–4, where MTO is coordinated via the oxygen of the former hydroxyl-group to MTO. The resulting complexes are very stable but not particularly catalytically active if no electron acceptor resides on the Schiff base. The electron withdrawing groups placed on the Schiff base ligand have the effect

  3. 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 IC?? value of DBHB as the most active enzyme inhibitor encountered in this study amounts to 0.84 ?M. Inhibition of phenoloxidase by DBHB is likely due to complexation of copper(II) ions from the catalytic centre of the enzyme by the ?-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

  4. Synthesis and spectroscopic studies on the Schiff base ligand derived from condensation of 2-furaldehyde and 3,3'-diaminobenzidene, L and its complexes with Co(II), Ni(II), Cu(II) and Zn(II): comparative DNA binding studies of L and its Cu(II) and Zn(II) complexes.

    PubMed

    Shakir, Mohammad; Abbasi, Ambreen; Khan, Asad U; Khan, Shahper N

    2011-01-01

    The Schiff base ligand, N,N'-bis-(2-furancarboxaldimine)-3,3'-diaminobenzidene (L) obtained by condensation of 2-furaldehyde and 3,3'-diaminobenzidene, was used to synthesize the mononuclear complexes of the type, [M(L)](NO3)2 [M=Co(II), Ni(II), Cu(II) and Zn(II)]. The newly synthesized ligand, (L) and its complexes have been characterized on the basis of the results of the elemental analysis, molar conductance, magnetic susceptibility measurements and spectroscopic studies viz, FT-IR, 1H and 13C NMR, mass, UV-vis and EPR. EPR, UV-vis and magnetic moment data revealed a square planar geometry for the complexes with distortion in Cu(II) complex and conductivity data show a 1:2 electrolytic nature of the complexes. Absorption and fluorescence spectroscopic studies support that Schiff base ligand, L and its Cu(II) and Zn(II) complex exhibit significant binding to calf thymus DNA. The highest binding affinity in case of L may be due to the more open structure as compared to the metal coordinated complexes. PMID:21041112

  5. Chelating ability and biological activity of hesperetin Schiff base.

    PubMed

    Lodyga-Chruscinska, Elzbieta; Symonowicz, Marzena; Sykula, Anna; Bujacz, Anna; Garribba, Eugenio; Rowinska-Zyrek, Magdalena; Oldziej, Stanislaw; Klewicka, Elzbieta; Janicka, Magdalena; Krolewska, Karolina; Cieslak, Marcin; Brodowska, Katarzyna; Chruscinski, Longin

    2015-02-01

    Hydrazone hesperetin Schiff base (HHSB) - N-[(±)-[5,7-dihydroxy-2-(3-hydroxy-4-methoxy-phenyl)chroman-4-ylidene]amino]benzamide has been synthesized and its crystal structure was determined. This compound was used for the formation of Cu(II) complexes in solid state and in solution which were characterized using different spectroscopic methods. The analyses of potentiometric titration curves revealed that monomeric and dimeric complexes of Cu(II) are formed above pH7. The ESI-MS (electrospray ionization-mass spectrometry) spectra confirmed their formation. The EPR and UV-visible spectra evidenced the involvement of oxygen and nitrogen atoms in Cu(II) coordination. Hydrazone hesperetin Schiff base can show keto-enol tautomerism and coordinate Cu(II) in the keto (O(-), N, Oket) and in the enolate form (O(-), N, O(-)enol). The semi-empirical molecular orbital method PM6 and DFT (density functional theory) calculations have revealed that the more stable form of the dimeric complex is that one in which the ligand is present in the enol form. The CuHHSB complex has shown high efficiency in the cleavage of plasmid DNA in aqueous solution, indicating its potential as chemical nuclease. Studies on DNA interactions, antimicrobial and cytotoxic activities have been undertaken to gain more information on the biological significance of HHSB and copper(II)-HHSB chelate species. PMID:25486205

  6. Synthesis, characterization and crystal structure of copper(II) ternary complex with cinoxacin and histamine

    Microsoft Academic Search

    Egla Yareth Bivián-Castro; Francisco Cervantes-Lee; Guillermo Mendoza-D??az

    2004-01-01

    In order to enhance the knowledge of how quinolones may exert their antibacterial action, the synthesis of a new copper(II) mixed ligand, containing histamine complex was carried out. Crystal structure of [Cu(hsm)(cnx)NO3]H2O shows that Cu(II) cation displays a distorted square pyramidal geometry. Cinoxacinate (cnx) acts as bidentate ligand bonded to the Cu(II) ion through the oxygen atoms of the 3-carboxylate

  7. Synthesis and characterization of lanthanide(III) (La, Gd, Yb, Y) disalicylidene-1,2-phenylenediamine (H{sub 2}dsp) Schiff-base complexes

    SciTech Connect

    Chen, Huiyong; Archer, R.D. [Univ. of Massachusetts, Amherst, MA (United States)

    1994-11-09

    Novel rare earth (III) disalicylidene-1,2-phenylenediamine(H{sub 2}dsp) complexes with the formula M[Ln(dsp){sub 2}] (M = Li, Na, K, Cs) were prepared. UV-visible absorption and NMR were used to study the disproportionation equilibrium for these complexes in DMSO. Structures for these complexes are suggested.

  8. Spacer-armed copper(II) complexes with benzenecarboxylic acids and trifluoroacetylacetone aroylhydrazones.

    PubMed

    Shul'gin, Victor F; Konnik, Oleg V; Gusev, Alexey N; Bo?a, Roman; Dlhá?, Lubor; Rusanov, Eduard B; Alexandrov, Grygory G; Eremenko, Igor L; Linert, Wolfgang

    2013-12-28

    New bi- and trinuclear copper(ii) complexes of aroylhydrazones of TFA and benzenecarboxylic acids were synthesized and characterized. Despite long range intramolecular CuCu distances of about 10 Å, exchange couplings between paramagnetic centres are observed with J values of 0.33 and 0.37 cm(-1) in binuclear complexes, and -0.33 cm(-1) in trinuclear complexes. Seven hyperfine peaks with a value of aCu = 37.0 × 10(-4) cm(-1) are observed in EPR spectra of binuclear complexes. The possible mechanisms responsible for the observed weak long range coupling via aromatic spacers are discussed. PMID:24092232

  9. New acyclic 1,2,4-triazole-based Schiff base hydrazone: Synthesis, characterization, spectrophotometric and computational studies

    NASA Astrophysics Data System (ADS)

    Khanmohammadi, Hamid; Erfantalab, Malihe; Azimi, Golamhassan

    2013-03-01

    A new 1,2,4-triazole-based Schiff base hydrazone with N, O, S donor set of atoms, H4L, has been prepared by condensation reaction of N,N'-bis(3-formyl-5-methylsalicylidene)ethane-1,2-diamine, H2L, with 4-amino-3-(4-pyridyl)-5-mercapto-1,2,4-triazole. The structure of H4L was characterized by using FT-IR, UV-Vis and 1H NMR spectroscopic methods as well as elemental analysis data. The formation constants of copper(II), cadmium(II), mercury(II) and silver(I) complexes of H4L in DMSO were calculated using a hard model chemometrics method applying the spectrophotometric data. The protonation constants of H4L were also measured in DMSO-water (1:10) mixture. Furthermore, 1H chemical shifts of H4L were studied by the gauge independent atomic orbital (GIAO) and continuous set of gauge transformations (CSGTs) methods at the level of density functional theory using B3LYP/6-311++G* basis sets in gas phase. The computed chemical shifts are in reasonably good agreement with the experimental data.

  10. Synthesis and characterization of Cu(II) complexes of tetradentate and tridentate symmetrical Schiff base ligands involving o -phenelenediamine, salicylaldehyde and diacetylmonoxime

    Microsoft Academic Search

    Debdulal Maity; Michael G. B. Drew; Jeffrey F. Godsell; Saibal Roy; Gurucharan Mukhopadhyay

    2010-01-01

    A mononuclear complex [CuL] (1), a binuclear complex [Cu2LCl2(H2O)] (2), a trinuclear complex [Cu3L2](ClO4)2 (3) involving o-phenylenediamine and salicylaldehyde and another binuclear complex of a tridentate ligand (H2L1) [Cu2L21](CH3COO)2 (4) involving o-phenylenediamine and diacetylmonoxime have been synthesized, where H2L = N,N?-o-phenylenebis(salicylideneimine) and H2L1 = 3-(2-aminophenylimino)butan-2-one oxime. All the complexes have been characterized by elemental analyses, spectral and\\u000a magnetic studies. The binuclear complex (2) was

  11. Influence of electron beam irradiation on spectral, thermal, morphological and catalytic properties of Co(II) complex immobilized on chitosan's Schiff base.

    PubMed

    Antony, R; Theodore David, S; Karuppasamy, K; Sanjeev, Ganesh; Balakumar, S

    2014-04-24

    This study was carried out to investigate the effect of electron beam irradiation on the spectral and catalytic properties of chitosan supported (ONClCl) tetra coordinated Co(II) complex, [Co(OIAC)Cl2]. The complex was subjected to electron beam irradiation of 100 Gy, 1 kGy and 10 kGy doses. Chain scission of chitosan was observed on irradiation at 100 Gy and 10 kGy and chain linking at 1 kGy as evidenced by viscosity and FT-IR spectroscopic studies. This observation was also confirmed by thermo gravimetric and differential thermogravimetric (TG-DTG) analysis. It revealed that the thermal stability of the complex was increased at 1 kGy irradiation and decreased at 100 Gy and 10 kGy. In addition, the effect of electron beam irradiation on the surface morphology of the complex was studied by scanning electron microscopy. Catalytic abilities of both non-irradiated complex and irradiated complexes were determined and compared in the cyclohexane oxidation using hydrogen peroxide oxidant. The catalytic activity was found to increase after irradiation at all doses. Though the complex irradiated at 10 kGy showed highest conversion efficiency, irradiation at 1 kGy is suggested as the best dose due to the extensive reusability and adequate catalytic ability of the complex. PMID:24486862

  12. Highly valence-diversified binuclear uranium complexes of a schiff-base polypyrrolic macrocycle: prediction of unusual structures, electronic properties, and formation reactions.

    PubMed

    Yao, Jun; Zheng, Xiu-Jun; Pan, Qing-Jiang; Schreckenbach, Georg

    2015-06-01

    On the basis of relativistic density functional theory calculations, homo- and heterovalent binuclear uranium complexes of a polypyrrolic macrocycle in a U-O-U bridging fashion have been investigated. These complexes show a variety of oxidation states for uranium ranging from III to VI, which have been confirmed by the calculated electron-spin density on each metal center. An equatorially 5-fold uranyl coordination mode is suitable for hexavalent uranium complexes, while silylation of the uranyl oxo is favored by pentavalent uranium. Uranyl oxo ligands are not required anymore for the coordination environment of tetra- and trivalent uranium because of their replacement by strong donors such as tetrahydrofuran and iodine. Optimization of binuclear U(VI)-U(III) complexes with various coordinating modes of U(III), donor numbers, and donor types reveals that 0.5-1.0 electron has been transferred from U(III) to U(VI). Consequently, U(V)-U(IV) complexes are more favorable. Electronic structures and formation reactions of several representative uranium complexes were calculated. For example, a 5f-based ?(U-U) bonding orbital is found in the diuranium(IV) complex, rationalizing the fact that it shows the shortest U-U distance (3.82 Å) among the studied binuclear complexes. PMID:25955709

  13. Spectroscopic, crystal structural and electrochemical studies of zinc(II)-Schiff base complex obtained from 2,3-diaminobenzene and 2-hydroxy naphthaldehyde

    NASA Astrophysics Data System (ADS)

    Ouari, Kamel; Bendia, Sabrina; Weiss, Jean; Bailly, Corinne

    2015-01-01

    Mononuclear zinc(II) complex, [Zn(II)L], where L is a dianionic ligand, has been synthesized and characterized by elemental analysis, electronic, IR and NMR [1H, 13C, DEPT, 1H-1H COSY, ROESY, HSQC and HMBC] spectroscopic techniques. Structural analysis of the complex by single crystal X-ray crystallography shows the presence of a distorted square planar coordination geometry (NNOO) of the metal center. The crystal of the title complex C28H18N2O2Zn belongs to the orthorhombic system with space group Pmn21. Electrochemical behavior of the Zn(II)L complex has been investigated by cyclic voltammetry on glassy carbon and platinum electrodes in DMF at 100 mV/s scan rate.

  14. Spectroscopic, crystal structural and electrochemical studies of zinc(II)-Schiff base complex obtained from 2,3-diaminobenzene and 2-hydroxy naphthaldehyde.

    PubMed

    Ouari, Kamel; Bendia, Sabrina; Weiss, Jean; Bailly, Corinne

    2015-01-25

    Mononuclear zinc(II) complex, [Zn(II)L], where L is a dianionic ligand, has been synthesized and characterized by elemental analysis, electronic, IR and NMR [(1)H, (13)C, DEPT, (1)H-(1)H COSY, ROESY, HSQC and HMBC] spectroscopic techniques. Structural analysis of the complex by single crystal X-ray crystallography shows the presence of a distorted square planar coordination geometry (NNOO) of the metal center. The crystal of the title complex C28H18N2O2Zn belongs to the orthorhombic system with space group Pmn21. Electrochemical behavior of the Zn(II)L complex has been investigated by cyclic voltammetry on glassy carbon and platinum electrodes in DMF at 100 mV/s scan rate. PMID:25128674

  15. Mimicking peroxidase activity by a polymer-supported oxidovanadium(IV) Schiff base complex derived from salicylaldehyde and 1,3-diamino-2-hydroxypropane.

    PubMed

    Maurya, Mannar R; Chaudhary, Nikita; Avecilla, Fernando; Correia, Isabel

    2015-06-01

    The polymer-supported oxidovanadium(IV) complex PS-[V(IV)O(sal-dahp)] (2) (PS=chloromethylated polystyrene crosslinked with 5% divinylbenzene, and H3sal-dahp=dibasic pentadentate ligand derived from salicylaldehyde and 1,3-diamino-2-hydroxypropane) was prepared from the corresponding monomeric oxidovanadium(IV) complex [V(IV)O(Hsal-dahp)(DMSO)] (1), characterized and successfully used as catalyst for the peroxidase-like oxidation of pyrogallol. The oxidation of pyrogallol to purpurogallin with PS-[V(IV)O(sal-dahp)] (2) was achieved under mild conditions at pH7 buffered solution. Plausible intermediate species formed during peroxidase mimicking experiments are proposed, by studying the model complex [V(IV)O(Hsal-dahp)(DMSO)] (1) by UV-visible and (51)V NMR spectroscopies. The high peroxidase mimicking ability of polymer-supported complex 2, its stability in a wide pH range, the easy separation from the reaction media, and the reusability without considerable decrease in activity, suggest that this heterogeneous catalyst has high potential for application in sustainable industrial catalysis. PMID:25747150

  16. Thermochemical study of complexation and solvation in ?-alanine-Cu(NO 3 ) 2 -water-ethanol system: 1. Enthalpy characteristics of complexing copper(II) Ion with ?-alanine

    Microsoft Academic Search

    V. N. Vandyshev; S. F. Ledenkov

    2011-01-01

    The heats of the reaction between copper(II) nitrate and sodium alaninate and the heats of dilution of Cu(NO3)2 solution in aqueous ethanol have been measured at 298 K using calorimetry. The standard molar enthalpies of the reaction\\u000a of copper(II) complexing with alaninate ion in solvents of various compositions have been calculated. The complexing process\\u000a in ethanol is more exothermic than

  17. Fascinating role of the number of f electrons in dipolar and octupolar contributions to quadratic hyperpolarizability of trinuclear lanthanides-biscopper Schiff base complexes.

    PubMed

    Gulino, Antonino; Fragalà, Ignazio L; Lupo, Fabio; Malandrino, Graziella; Motta, Alessandro; Colombo, Alessia; Dragonetti, Claudia; Righetto, Stefania; Roberto, Dominique; Ugo, Renato; Demartin, Francesco; Ledoux-Rak, Isabelle; Singh, Anu

    2013-07-01

    The trinuclear [Ln(NO3)3(CuL)2] complexes (Ln = La, Ce, Sm, Eu and Er, L = N,N'-1,3-propylen-bis(salicylideniminato) have been investigated by a combination of HLS and EFISH techniques to evaluate both the dipolar and octupolar contributions to their significant quadratic hyperpolarizability and to confirm that f electrons may tune their second-order NLO response. In the complexes investigated, the major contribution to the total quadratic hyperpolarizability is largely controlled by the octupolar contribution, but the values of both ?EFISH and [parallel]?(J=1)[parallel], that is the dipolar part, are significantly influenced by the number of f electrons, confirming that the unexpected polarizable character of f electrons may be the origin of such fascinating evidence. PMID:23781952

  18. Acute Toxicity and Gastroprotection Studies of a New Schiff Base Derived Copper (II) Complex against Ethanol-Induced Acute Gastric Lesions in Rats

    PubMed Central

    Hassandarvish, Pouya; Gwaram, Nura Suleiman; A. Hadi, A. Hamid; Mohd Ali, Hapipah; Majid, Nazia; Abdulla, Mahmood Ameen

    2012-01-01

    Background Copper is an essential element in various metabolisms. The investigation was carried out to evaluate acute gastroprotective effects of the Copper (II) complex against ethanol-induced superficial hemorrhagic mucosal lesions in rats. Methodology/Principal Findings Rats were divided into 7 groups. Groups 1 and 2 were orally administered with Tween 20 (10% v/v). Group 3 was orally administered with 20 mg/kg omeprazole (10% Tween 20). Groups 4–7 received 10, 20, 40, and 80 mg/kg of the complex (10% Tween 20), respectively. Tween 20 (10% v/v) was given orally to group 1 and absolute ethanol was given orally to groups 2–7, respectively. Rats were sacrificed after 1 h. Group 2 exhibited severe superficial hemorrhagic mucosal lesions. Gastric wall mucus was significantly preserved by the pre-treatment complex. The results showed a significant increase in glutathione (GSH), superoxide dismutase (SOD), nitric oxide (NO), and Prostaglandin E2 (PGE2) activities and a decrease in malondialdehyde (MDA) level. Histology showed marked reduction of hemorrhagic mucosal lesions in groups 4–7. Immunohistochemical staining showed up-regulation of Hsp70 and down-regulation of Bax proteins. PAS staining of groups 4–7 showed intense stain uptake of gastric mucosa. The acute toxicity revealed the non-toxic nature of the compound. Conclusions/Significance The gastroprotective effect of the Copper (II) complex may possibly be due to preservation of gastric wall mucus; increase in PGE2 synthesis; GSH, SOD, and NO up-regulation of Hsp70 protein; decrease in MDA level; and down-regulation of Bax protein. PMID:23251568

  19. Electrocatalytic determination of sumatriptan on the surface of carbon-paste electrode modified with a composite of cobalt/Schiff-base complex and carbon nanotube.

    PubMed

    Amiri, Mandana; Pakdel, Zohreh; Bezaatpour, Abolfazl; Shahrokhian, Saeed

    2011-06-01

    The electrochemical oxidation of sumatriptan on the surface of carbon paste electrode modified with multi-walled carbon nanotube and cobalt methyl-salophen complex is studied by using cyclic voltammetry and polarization studies. The results indicate that the drug is irreversibly oxidized in a one electron oxidation mechanism. It was found that the peak potential shifted negatively with increasing pH, confirms that H(+) participate in the oxidation process. The electrode is shown to be very effective for the detection of sumatriptan in the presence of other biological reductant compounds. The prepared modified electrode exhibits a very good resolution between the voltammetric peaks of sumatriptan, ascorbic acid and uric acid, which makes it suitable for the simultaneous detection of sumatriptan in the presence of these compounds in clinical and pharmaceutical preparations. It can be concluded that multi-walled carbon nanotube and Shiff base complex have synergic effect on electroacatalytic oxidation of sumatriptan. A linear range of 1-1000?M and detection limit of 0.3?M was obtained for sumatriptan from DPV measurements using this electrode in 0.1M acetate buffered solution of pH 5.0. The electrode has been applied successfully for the determination of sumatriptan in synthetic serum and commercial tablets. PMID:21470920

  20. Olefin Metathesis Mediated By: - Schiff Base Ru-Alkylidenes -Ru-Alkylidenes Bearing Unsymmetrical NH Ligands

    NASA Astrophysics Data System (ADS)

    Monsaert, Stijn; Voort, Pascal Van Der; Ledoux, Nele; Allaert, Bart; Drozdzak, Renata; Verpoort, Francis

    The classic Grubbs second-generation complex 2 was modified through 1. The introduction of a bidentate Schiff base ligand 2. Changes in the amino side groups of the NHC ligand Representative olefin metathesis test reactions show the effects induced by the ligand modifications and demonstrate some interesting new properties of the described catalysts. catalysts.

  1. Complexation of nitrogen and sulphur donor Schiff's base ligand to Cr(III) and Ni(II) metal ions: Synthesis, spectroscopic and antipathogenic studies

    NASA Astrophysics Data System (ADS)

    Sharma, Amit Kumar; Chandra, Sulekh

    2011-01-01

    2,6-Diacetyl pyridine based ligand was synthesized by the reaction of 2,6-diacetyl pyridine with thiocarbohydrazide in presence of acetic acid. The coordination compounds with Cr(III) and Ni(II) metal ions having [Cr(L)X]X 2 and [Ni(L)X]X compositions (where L = ligand and X = NO 3-, Cl - and CH 3COO -) were synthesized and characterized by physicochemical and spectral studies. The studies like elemental analyses, molar conductance measurements, magnetic susceptibility measurements, IR, UV-Vis, NMR, mass and EPR reveal that the complexes are octahedral. The compounds were examined against the pathogenic fungal and bacterial strains like Alternaria brassicae, Aspergillus niger, Fusarium oxysporum, Xanthomonas compestris and Pseudomonas aeruginosa. A. niger causes the diseases Apergillosis and Otomycosis in humans.

  2. Cytotoxicity of copper(II) complexes of N-salicylidene-L-glutamate: modulation by ascorbic acid.

    PubMed

    Paulikova, H; Kadlecikova, E; Suchanova, M; Valkova, Z; Rauko, P; Hudecova, D; Valent, A

    2008-01-01

    Cytotoxic/cytostatic activity of N-salicylidene-L-glutamato diaqua copper(II) complex (CuC) against mice leukemia cells L1210 has been estimated and their bioactivity was enhanced by addition of ascorbic acid. The Cu-complex with isoquinoline ligand (IQ-CuC) had stronger cytostatic effect (IC50 =15.6 microM) than parental complex (CuC) and its cytotoxicity several times increased in the presence of 0.1 mM ascorbic acid (IC50 =1.0 microM). The cytotoxicity has been caused by oxidative stress, enhanced creation of TBARS has been confirmed, and formation of 2',7'-dichlorofluorescein from 2',7'- dichlorodihydrofluorescein has been observed, also. Some hallmarks of apoptotic/necrotic death of L1210 cells have been observed by fluorescent microscopy after dyeing of cell with propidium iodide and Hoechst 33342. In addition, it was confirmed that both complexes in the presence of ascorbic acid cleavaged of pDNA. Although these copper complexes were initially prepared as substances with antioxidant properties we have showed that combined treatment of L1210 cells with IQCuC and ascorbic acid induced strong oxidative stress and death of cells. Our results confirmed that physiological concentration of ascorbic acid increases the cytostatic/cytotoxic efficiency of N-salicylidene-L-glutamato diaqua copper(II) complexes. PMID:18505346

  3. Kinetics and mechanisms of the oxidation of alcohols and hydroxylamines by hydrogen peroxide, catalyzed by methyltrioxorhenium, MTO, and the oxygen binding properties of cobalt Schiff base complexes

    SciTech Connect

    Zauche, Timothy

    1999-02-12

    Catalysis is a very interesting area of chemistry, which is currently developing at a rapid pace. A great deal of effort is being put forth by both industry and academia to make reactions faster and more productive. One method of accomplishing this is by the development of catalysts. Enzymes are an example of catalysts that are able to perform reactions on a very rapid time scale and also very specifically; a goal for every man-made catalyst. A kinetic study can also be carried out for a reaction to gain a better understanding of its mechanism and to determine what type of catalyst would assist the reaction. Kinetic studies can also help determine other factors, such as the shelf life of a chemical, or the optimum temperature for an industrial scale reaction. An area of catalysis being studied at this time is that of oxygenations. Life on this earth depends on the kinetic barriers for oxygen in its various forms. If it were not for these barriers, molecular oxygen, water, and the oxygenated materials in the land would be in a constant equilibrium. These same barriers must be overcome when performing oxygenation reactions on the laboratory or industrial scale. By performing kinetic studies and developing catalysts for these reactions, a large number of reactions can be made more economical, while making less unwanted byproducts. For this dissertation the activation by transition metal complexes of hydrogen peroxide or molecular oxygen coordination will be discussed.

  4. Zinc(II) complexes derived from the di-Schiff-base ligand N,N?-bis[1-(pyridin-2-yl)ethylidene]ethane-1,2-diamine (L A) and its hydrolytic-cleavage product N-[1-pyridin-2-yl)ethylidene]ethane-1,2-diamine (L): preparation, characterization and crystal structure of the 5-coordinate species [ZnLCl 2

    Microsoft Academic Search

    Sotiris Gourbatsis; Spyros P. Perlepes; Ian S. Butler; Nick Hadjiliadis

    1999-01-01

    The reactions of ZnX2 (X=Cl, Br) with the di-Schiff-base ligand N,N?-bis[1-(pyridin-2-yl)ethylidene]ethane-1,2-diamine (LA) were studied. The chemical identity of the products is solvent-dependent. The reactions in tetrahydrofuran give complexes [ZnLACl2] (1) and [ZnLABr2] (2). Treatment of LA with an equimolar, or excess, amount of ZnX2 in ethanol yields the five-coordinate complexes [ZnLCl2] (3) and [ZnLBr2] (4), where L is the mono-Schiff

  5. Hexa- and heptacoordinated manganese(II) dicyanamide complexes containing a tetradentate N-donor Schiff base: Syntheses, composition tailored architectures and magnetic properties

    NASA Astrophysics Data System (ADS)

    Bhar, Kishalay; Sutradhar, Dipu; Choubey, Somnath; Ghosh, Rajarshi; Lin, Chia-Her; Ribas, Joan; Ghosh, Barindra Kumar

    2013-11-01

    Two 1D coordination polymers [Mn(L)(?1,5-dca)(MeOH)]n(ClO4)n (1) and [Mn(L)(?1,5-dca)]n(PF6)n (2) and a dinuclear compound [Mn2(L)2(?1,5-dca)2(dca)2]?H2O (3) [L = N,N'-(bis-(pyridin-2-yl)benzylidene)-ethane-1,2-diamine; dca = dicyanamide] have been isolated using one-pot synthesis of the building components in appropriate molar ratios and characterized. X-ray structural studies reveal that 1 forms a zigzag 1D chain through single Mn-(NCNCN)-Mn units in which each heptacoordinated manganese(II) center adopts a distorted pentagonal bipyramidal geometry with an MnN6O chromophore occupied with four N atoms of L, two nitrile N atoms of monobridged ?1,5-dca and one O atom of MeOH. In 2, each hexacoordinated metal(II) center has a distorted octahedral coordination environment with an MnN6 chromophore bound by four N atoms of L and two nitrile N atoms of two different single bridged ?1,5-dca units; the latter connects other neighboring metal centers in a non-ending fashion affording a linear 1D chain. Complex 3 is dinuclear where two [Mn(L)]2+ units are connected by double ?1,5-dca bridges with a distorted pentagonal bipyramidal environment. Variable-temperature magnetic susceptibility measurements of 1-3 show weak antiferromagnetic interactions among the metal centers through ?1,5-dca bridges.

  6. 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.

  7. Nickel(II) and copper(II) complexes with pyridine-containing macrocycles bearing an aminopropyl pendant arm: synthesis,

    E-print Network

    Nazarenko, Alexander

    Nickel(II) and copper(II) complexes with pyridine-containing macrocycles bearing an aminopropyl of three five-coordinate nickel(II) complexes with pendant arm-containing macrocycles has been achieved-pyridine and a tripodal tetramine. Demetallation of the nickel(II) macrocycles yielded stable pentadentate ligands

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

    PubMed

    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)(NN)]Br2(1-2) [dipn=dipropylenetriamine, NN=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?g/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?M. The absorption spectrum of 2 in water was modeled by time-dependent density functional theory (TD-DFT). PMID:24632175

  9. Ferrocene-Based Tetradentate Schiff Bases as Supporting Ligands in Uranium Chemistry.

    PubMed

    Camp, Clément; Chatelain, Lucile; Mougel, Victor; Pécaut, Jacques; Mazzanti, Marinella

    2015-06-15

    Uranyl(VI), uranyl(V), and uranium(IV) complexes supported by ferrocene-based tetradentate Schiff-base ligands were synthesized, and their solid-state and solution structures were determined. The redox properties of all complexes were investigated by cyclic voltammetry. The bulky salfen-(t)Bu2 allows the preparation of a stable uranyl(V) complex, while a stable U(IV) bis-ligand complex is obtained from the salt metathesis reaction between [UI4(OEt2)2] and K2salfen. The reduction of the [U(salfen)2] complex leads to an unprecedented intramolecular reductive coupling of the Schiff-base ligand resulting in a C-C bond between the two ferrocene-bound imino groups. PMID:26010406

  10. Anion recognition by simple chromogenic and chromo-fluorogenic salicylidene Schiff base or reduced-Schiff base receptors

    NASA Astrophysics Data System (ADS)

    Dalapati, Sasanka; Jana, Sankar; Guchhait, Nikhil

    2014-08-01

    This review contains extensive application of anion sensing ability of salicylidene type Schiff bases and their reduced forms having various substituents with respect to phenolic sbnd OH group. Some of these molecular systems behave as receptor for recognition or sensing of various anions in organic or aqueous-organic binary solvent mixture as well as in the solid supported test kits. Development of Schiff base or reduced Schiff base receptors for anion recognition event is commonly based on the theory of hydrogen bonding interaction or deprotonation of phenolic -OH group. The process of charge transfer (CT) or inhibition of excited proton transfer (ESIPT) or followed by photo-induced electron transfer (PET) lead to naked-eye color change, UV-vis spectral change, chemical shift in the NMR spectra and fluorescence spectral modifications. In this review we have tried to discuss about the anion sensing properties of Schiff base or reduced Schiff base receptors.

  11. Computational Study of Copper(II) Complexation and Hydrolysis in Aqueous Solutions Using Mixed Cluster/Continuum Models

    E-print Network

    Goddard III, William A.

    Computational Study of Copper(II) Complexation and Hydrolysis in Aqueous Solutions Using Mixed and thermodynamic properties of Cu(II) species in aqueous solution. 1. Introduction Copper is a key component evidence that copper may be involved in the pathogenesis of atherosclerosis, Alzheimer's diseases

  12. 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.

  13. Copper(II) salicylideneglycinate complexes as potential antimicrobial agents

    Microsoft Academic Search

    Aladár Valent; Milan Meln??k; Daniela Hudecová; Barbora Dudová; Raikko Kivekäs; Markku R Sundberg

    2002-01-01

    The reaction of an ethanolic solutions of N-salicylideneglycinatoaquacopper(II) hemihydrate with urea, pyridine, 2,4-dimethylpyridine, 3,5-dimethylpyridine, quinoline, 4-methylquinoline, isoquinoline, or 3-methylisoquinoline in an equimolar ratio resulted in solid products containing complexes of the type Cu(salgly)L with distorted square pyramidal coordination polyhedra. The products were characterized by elemental analysis, electronic and EPR spectra, and magnetic susceptibility measurements. Moreover, the crystal and molecular structure

  14. Spectroscopic, solvent influence and thermal studies of ternary copper(II) complexes of diester and dinitrogen base ligands

    Microsoft Academic Search

    Adel A. A. Emara; Azza A. A. Abu-Hussein; Ahmed A. Taha; Nelly H. Mahmoud

    2010-01-01

    New mixed-ligand copper(II) complexes containing the bidentate dinitrogen ligands [N,N,N’,N’-tetramethylethylenediamine (tmen), 2,2’-bipyridine (bipy) and 1,10-phenanthroline (phen)] and the bidentate dioxygen ligands [diethylmalonate (DEM), ethylacetoacetate (EAA) and ethylbenzoylacetate (EBA)] were prepared. The complexes were characterized by elemental analysis, infrared, mass and ESR spectral data, magnetic and molar conductance measurements and thermal gravimetric analysis. From the investigation, the geometries of the complexes

  15. Anomeric and tautomeric equilibria in D-2-glucosamine Schiff bases

    NASA Astrophysics Data System (ADS)

    Ko?odziej, B.; Grech, E.; Schilf, W.; Kamie?ski, B.; Makowski, M.; Rozwadowski, Z.; Dziembowska, T.

    2007-11-01

    The structure of some glucosamine Schiff bases has been studied by means of ab initio RHF and DFT calculation and CP/MAS 13C and 15N NMR measurements. The anomeric and tautomeric equilibria in a DMSO solution have been studied by 1H, 13C and 15N NMR spectroscopy. The anomeric composition of D-2-glucosamine Schiff bases in the solid state and in DMSO solution has been shown to depends on the tautomeric form of Schiff bases and electronic properties of substituents on the aromatic ring.

  16. Grafting of a tetrahydro-salen copper(II) complex on surface modified mesoporous materials and its catalytic behaviour

    Microsoft Academic Search

    Ayyamperumal Sakthivel; Wei Sun; Gabriele Raudaschl-Sieber; Anthony S. T. Chiang; Marianne Hanzlik; Fritz E. Kühn

    2006-01-01

    A tetrahydro-salen copper(II) complex (1) is grafted on the iodosilane modified surfaces of MCM-41 and MCM-48. The presence of complex 1 on the surfaces is evidenced by 1H MAS–NMR, elemental analysis and TG-MS. The strucutre of the supports after modification remains intact, which is evident from powder XRD, N2 adsorption\\/desorption (BET), and TEM analysis. The grafted materials are applicable as

  17. Catalysis of Diribonucleoside Monophosphate Cleavage by Water Soluble Copper(II) Complexes of Calix[4]arene Based Nitrogen Ligands

    Microsoft Academic Search

    Roberta Cacciapaglia; Alessandro Casnati; Luigi Mandolini; David N. Reinhoudt; Riccardo Salvio; Andrea Sartori; Rocco Ungaro

    2006-01-01

    Calix[4]arenes functionalized at the 1,2-, 1,3-, and 1,2,3-positions of the upper rim with [12]ane-N3 ligating units were synthesized, and their bi- and trimetallic zinc(II) and copper(II) complexes were investigated as catalysts in the cleavage of phosphodiesters as RNA models. The results of comparative kinetic studies using monometallic controls indicate that the subunits of all of the zinc(II) complexes and of

  18. A Potentiometric and Spectroscopic Investigation of Copper(II)– and Zinc(II)–Orotate Complex Equilibria Under Physiological Conditions

    Microsoft Academic Search

    Brahim Hacht; Hassan Tayaa; Ahmed Benayad; Mostafa Mimouni

    2002-01-01

    A quantitative study of zinc(II) and copper(II) complex formation with orotic acid has been performed under physiological conditions (37°C; 0.15 mol-dm-3 NaCl) using the glass electrode potentiometric technique. Several species have been identified within the pH range 2–10 for the metal-to-ligand concentration ratios investigated. Three mononuclear complexes, ML, ML2, and ML2H-1, have been characterized with both metals. In addition, the

  19. Iron-Schiff Base Magnetic Polymers. Synthesis and Characterization

    Microsoft Academic Search

    M. Fujiwara; W. Mori; K. Yamaguchi

    1995-01-01

    A magnetically active organometallic iron-Schiff base polymer, molecular weight was between about 4,000 and 50,000 daltons, was synthesized. This polymer comprised a multiplicity of Schiff base tridentate chelating groups having the capacity to combine with the iron (II) or iron (III) ion of an organic salt.A magnetic susceptibility (?g) of this organic polymer was between about 1 × 10 cc\\/g

  20. Synthesis and crystal structure of metal complexes of Schiff bases derived from Glycylglycine and Salicylaldehyde [Ni(H2O)6(Ml)2]·nH2O?(M = Cu, Ni; L = C11H9N2O4)

    Microsoft Academic Search

    Yang Zou; Wen-Long Liu; Jing-Li Xie; Chun-Lin Ni; Zhao-Ping Ni; Yi-Zhi Li; Qing-Jin Meng; Yuan-Gen Yao

    2004-01-01

    Complexes [Ni(H2O)6(ML)2]·nH2O (M = Cu, Ni; L = Schiff base derived from glycylglycine and salicylaldehyde, C11H9N2O4) were synthesized and characterized. The [Ni(H2O)6(CuL)2]·10H2O complex 1 crystallized in the space group , with a = 7.217(1), b = 11.674(1), c = 12.678(1)?Å, ? = 66.56(1), ? = 76.60(1), ??= 80.46(1)°, and Z = 1. The [Ni(H2O)6(NiL)2]·2H2O complex 2 crystallized in the group

  1. Chelating resins VII: studies on chelating resins of formaldehyde and furfuraldehyde-condensed phenolic Schiff base derived from 4,4?-diaminodiphenylsulphone and o-hydroxyacetophenone

    Microsoft Academic Search

    S Samal; N. K Mohapatra; S Acharya; R. K Dey

    1999-01-01

    The synthesis, characterization and capacity studies of two chelating resins having multiple functional groups capable of coordinating to several metal ions are reported. The resins were synthesized by condensing phenolic Schiff bases derived from 4,4?-diaminodiphenylsulphone and o-hydroxyacetophenone with formaldehyde\\/furfuraldehyde. The polymeric Schiff bases were found to form complexes readily with several transition metal ions. The resins were completely soluble in

  2. Synthesis and crystal structure of a ternary copper(II) complex of 2,2?-bipyridine and picrate: Molecular docking, reactivity towards DNA and in vitro anticancer activity

    NASA Astrophysics Data System (ADS)

    Zheng, Kang; Jiang, Man; Li, Yan-Tuan; Wu, Zhi-Yong; Yan, Cui-Wei

    2014-01-01

    A new mononuclear ternary copper(II) complex with mixed ligands of 2,2?-bipyridine (bpy) and picrate (pic), namely [Cu(bpy)(pic)2], has been synthesized and characterized by elemental analysis, molar conductivity measurement, IR and electronic spectral studies, and single-crystal X-ray diffraction. The crystal structure analysis reveals the presence of two crystallographic independent molecules in an asymmetric unit. The copper(II) atoms are in elongated octahedral coordination geometries. A three-dimensional supermolecular network is formed through non-classical C-H⋯O hydrogen bonds. The DNA-binding properties of the copper(II) complex are investigated both theoretically and experimentally, revealing that the copper(II) complex can interact with HS-DNA in the mode of intercalation, and the molecular docking of the copper(II) complex with the self-complementary DNA duplex of sequence d(ACCGACGTCGGT)2 facilitates the binding events. The in vitro anticancer activities suggest that the copper(II) complex is active against the selected tumor cell lines.

  3. Catalysis of diribonucleoside monophosphate cleavage by water soluble copper(II) complexes of calix[4]arene based nitrogen ligands.

    PubMed

    Cacciapaglia, Roberta; Casnati, Alessandro; Mandolini, Luigi; Reinhoudt, David N; Salvio, Riccardo; Sartori, Andrea; Ungaro, Rocco

    2006-09-20

    Calix[4]arenes functionalized at the 1,2-, 1,3-, and 1,2,3-positions of the upper rim with [12]ane-N(3) ligating units were synthesized, and their bi- and trimetallic zinc(II) and copper(II) complexes were investigated as catalysts in the cleavage of phosphodiesters as RNA models. The results of comparative kinetic studies using monometallic controls indicate that the subunits of all of the zinc(II) complexes and of the 1,3-distal bimetallic copper(II) complex 7-Cu(2) act as essentially independent monometallic catalysts. The lack of cooperation between metal ions in the above complexes is in marked contrast with the behavior of the 1,2-vicinal bimetallic copper(II) complex 6-Cu(2), which exhibits high catalytic efficiency and high levels of cooperation between metal ions in the cleavage of HPNP and of diribonucleoside monophosphates NpN'. A third ligated metal ion at the upper rim does not enhance the catalytic efficiency, which excludes the simultaneous cooperation in the catalysis of the three metal ions in 8-Cu(3). Rate accelerations relative to the background brought about by 6-Cu(2) and 8-Cu(3) (1.0 mM catalyst, water solution, pH 7.0, 50 degrees C) are on the order of 10(4)-fold, largely independent of the nucleobase structure, with the exception of the cleavage of diribonucleoside monophosphates in which the nucleobase N is uracil, namely UpU and UpG, for which rate enhancements rise to 10(5)-fold. The rationale for the observed selectivity is discussed in terms of deprotonation of the uracil moiety under the reaction conditions and complexation of the resulting anion with one of the copper(II) centers. PMID:16967984

  4. Synthesis, structure characterization, DNA binding, and cleavage properties of mononuclear and tetranuclear cluster of copper(II) complexes.

    PubMed

    Vafazadeh, Rasoul; Hasanzade, Naime; Heidari, Mohammad Mehdi; Willis, Anthony C

    2015-01-01

    Two copper(II) complexes, cluster 1, and mononuclear 2, have been synthesized by reacting acetylacetone and benzohydrazide (1:1 ratio for 1 and 1:2 ratio for 2) with CuCl(2) in a methanol solution. In 2, which is a new complex, the ligand acts as a tetradentate which binds the metal ion via two amide-O atoms and two imine-N atoms providing an N(2)O(2) square-planar around the copper(II) ion. The absorption spectra data evidence strongly suggested that the two copper(II) compounds could interact with CT-DNA (intrinsic binding constant, K(b) = 0.45×10(4) M-1 for 1 and K(b) = 2.39×10(4) M-1 for 2). The super coiled plasmid pBR322 DNA cleavage ability was studied with 1 and 2 in the presence and absence of H(2)O(2) as an oxidant. In both the absence and the presence of an oxidizing agent, complex 2 exhibited no nuclease activity. However, even in the absence of an oxidant, complex 1 exhibited significant DNA cleavage activity. PMID:25830968

  5. Synthesis, characterization, DNA binding, cleavage activity and cytotoxicity of copper(II) complexes.

    PubMed

    Li, Mei-Jin; Lan, Tao-Yu; Cao, Xiu-Hui; Yang, Huang-Hao; Shi, Yupeng; Yi, Changqing; Chen, Guo-Nan

    2014-02-21

    Three new mononuclear copper(II) complexes, [Cu(L2)](2+) (1), [Cu(acac)(L)](+) (2), and [Cu(acac-Cl)(L)](+) (3) (L = 2-(4-pyridine)oxazo[4,5-f]1,10-phenanthroline (4-PDOP); acac = acetylacetone; acac-Cl = 3-chloroacetylacetone), have been synthesized and characterized by elemental analysis, high resolution mass spectrometry (Q-TOF), and IR spectroscopy. Two of the complexes were structurally characterized by single-crystal X-ray diffraction techniques. Their interactions with DNA were studied by UV-vis absorption and emission spectra, viscosity, thermal melting, DNA unwinding assay and CD spectroscopy. The nucleolytic cleavage activity of the compounds was carried out on double stranded pBR322 circular plasmid DNA by using a gel electrophoresis experiment in the presence and absence of an oxidant (H2O2). Active oxygen intermediates such as hydroxyl radicals and hydrogen peroxide generated in the presence of L and complexes 1-3 may act as active species for the DNA scission. The cytotoxicity of the complexes against HepG2 cancer cells was also studied. PMID:24336842

  6. 3-Pyridylmethanol vs. N,N?-diethylnicotinamide in copper(II) complex formation - A comparative EPR study

    NASA Astrophysics Data System (ADS)

    Husáriková, L.; Repická, Z.; Valigura, D.; Valko, M.; Mazúr, M.

    2013-10-01

    Copper(II) complexes, formed from 4-chlorosalicylic acid anion A (A = 4-Clsal-), different copper(II) salts (Cu(ac)2 or CuSO4) and different N-donor ligands B (B = 3-pyridylmethanol (ron) or N,N'-diethylnicotinamide (denia)) with varying N-donor ligand-to-metal ratio (x), were studied by EPR spectroscopy in the frozen water/methanol (1:3 v/v) solutions. The number of ligand B molecules coordinated to Cu(II) central ion was determined from the nitrogen perpendicular and parallel superhyperfine splitting multiplets of Cu(II) EPR spectra. It was found for both N-donor ligands: (i) At lower ligand B concentrations (x = 1, 2), [CuB] and/or [CuB2] species having one and/or two molecules of ligands B in equatorial position were dominant. The dominant ternary complex particles were [CuA2B2] species. (ii) At higher ligand B concentrations (x ? 4) the formation of [CuB3] and/or [CuB4] species having three and/or four molecules of ligands B in equatorial position was confirmed. Such information is not possible to get from Cu(II) EPR spectra of powdered samples of given copper(II) complexes.

  7. 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]ClO4?H2O(1), [Cu(bpy)2OAc]ClO4?H2O(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.

  8. 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

  9. Synthesis, crystal structure and magnetism of three novel copper(II) complexes with pyrazole-based ligands

    NASA Astrophysics Data System (ADS)

    Santos, Igor F.; Guedes, Guilherme P.; Mercante, Luiza A.; Bernardino, Alice M. R.; Vaz, Maria G. F.

    2012-03-01

    In this work we present the synthesis, crystal structure and magnetic properties of three copper(II) pyrazole-based complexes. These compounds were prepared by reactions between the ligands (L1 = 5-amino-1-phenyl-1H-pyrazole-4-carbonitrile, L2 = 5-amino-1-(4'metoxiphenyl)-1H-pyrazole-4-carbonitrile and L3 = Ethyl 5-amino-1-phenyl-1H-pyrazole-4-carboxylate) and CuCl2·2H2O using an appropriate solvent. The crystalline structures of [Cu(L1)2Cl2] (1), [Cu(L2)2Cl2] (2) and [Cu(L3)2Cl2] (3) showed that copper ion is coordinated by two pirazolic ligands through pyridinic nitrogen atom and two chloride ions in a distorted square-planar geometry. The magnetic measurements revealed a paramagnetic behavior for (1) and weak antiferromagnetic coupling between copper(II) ions in (2) and (3). Due to the presence of labile chloride ions in the structures, these monomeric copper(II) complexes may be used as building blocks in the synthesis of molecular magnetic compounds.

  10. 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 ?g/mL.

  11. A new azido-bridged copper(II) complex containing nitronyl nitroxide radicals: Syntheses, crystal structures

    NASA Astrophysics Data System (ADS)

    Liu, G.; Chen, B.; Cheng, J. T.

    2014-12-01

    A new azido-bridged copper(II) complex with nitronyl nitroxide radicals Cu ( NITpPy)4(N3)2 ( NITpPy = 4-pyridyl-4,4,5,5-tetramethylimidaz-line-3-oxide-1-oxyl) has been prepared and structurally characterized by single-crystal X-ray diffraction. The complex crystallizes in triclinic, space group , Z = 1. Crystal data: C48H64CuN18O8, M r = 1084.71, a = 7.1334(11), b = 13.718(2), c = 14.136(2) Å, ? = 88.425(2)°, ? = 78.528(2)°, ? = 87.390(2)°, V = 1354.0(4) Å3, D c = 1.330 g/cm3, ?(Mo K?) = 0.472 mm-1, F(000) = 571, R = 0.0735 and wR = 0.1140 for 4962 observed reflections with I > 2?( I). The X-ray analysis reveals that Cu(II) ion resides in a perfect octahedron center. The units of [Cu ( NITpPy)4(N3)2] were connected as 3-D network structure by the nonclassical intermolecular H-bonds.

  12. Spectroscopic Characterization of Oxime Ligands and Their Complexes

    Microsoft Academic Search

    Cumali Çelik; Zeynep Ulukanli; Mehmet Tümer; Selahattin Serin

    2003-01-01

    New imine–oxime ligands H3L–H3L have been obtained from reactions of the Schiff base ligands H2B–H2B with monochloroglyoxime. Mononuclear copper(II), cobalt(II), nickel(II), vanadyl(IV) and zinc(II) complexes of the imine–oxime ligands H3L–H3L have been prepared and characterized by elemental analyses, infrared and electronic spectra, magnetic moment and molar conductance data. The molar conductance data show that the complexes are non?electrolytes. When the

  13. Synthesis, structures, electrochemistry and catalytic activities of copper(II) and palladium(II) complexes with asymmetric tetraazacycloannulenes

    Microsoft Academic Search

    E. H. Kim; D. I. Kim; H. S. Lee; H. G. Na; J. C. Byun; J. H. Choi; Y. C. Park

    2007-01-01

    Copper(II) and palladium(II) complexes with 15-membered asymmetric 5,9-dihydro-2,4,10,12-tetramethyl-1,5,9,13-monobenzotetraazacyclo[15]tetradecine have been synthesized and characterized. The electrochemical behaviors of the complexes showed a reduction and two one-electron irreversible oxidation waves in given potential ranges due to the metal ion and macrocycle ring, respectively. The electrocatalytic reduction of dioxygen on glassy carbon electrodes electropolymerized by such 15-membered and 14-membered tetraazaannulene complexes occurred at

  14. Copper(II) complexes with 4-hydroxyacetophenone-derived acylhydrazones: Synthesis, characterization, DNA binding and cleavage properties

    NASA Astrophysics Data System (ADS)

    Gup, Ramazan; Gökçe, Cansu; Aktürk, Selçuk

    2015-01-01

    Two new Cu(II) complexes of Schiff base-hydrazone ligands, hydroxy-N?-[(1Z)-1-(4-hydroxyphenyl)ethylidene]benzohydrazide [H3L1] and ethyl 2-(4-(1-(2-(4-(2-ethoxy-2-oxoethoxy)benzoyl)hydrazono)ethyl)phenoxy)acetate (HL2) have been synthesized and then characterized by microcopy and spectral studies. X-ray powder diffraction illustrates that [Cu(L2)2] complex is crystalline in nature whereas [Cu(H2L1)2]·2H2O has an amorphous structure. Binding of the copper complexes with Calf thymus DNA (CT-DNA) has been investigated by UV-visible spectra, exhibiting non-covalent binding to CT-DNA. DNA cleavage experiments have been also investigated by agarose gel electrophoresis in the presence and absence of an oxidative agent (H2O2). The effect of complex concentration on the DNA cleavage reaction has been also studied. Both copper complexes show nuclease activity, which significantly depends on concentrations of the complexes, in the presence of H2O2 through oxidative mechanism whereas they slightly cleavage DNA in the absence an oxidative agent.

  15. Schiff Base Metal Derivatives Enhance the Expression of HSP70 and Suppress BAX Proteins in Prevention of Acute Gastric Lesion

    PubMed Central

    Gwaram, Nura Suleiman; Al-Obaidi, Mazen M. Jamil; Soleimani, A. F.; Ali, Hapipah Mohd; Abdul Majid, Nazia

    2013-01-01

    Schiff base complexes have appeared to be promising in the treatment of different diseases and disorders and have drawn a lot of attention to their biological activities. This study was conducted to evaluate the regulatory effect of Schiff base metal derivatives on the expression of heat shock proteins (HSP) 70 and BAX in protection against acute haemorrhagic gastric ulcer in rats. Rats were assigned to 6 groups of 6 rats: the normal control (Tween 20 5% v/v, 5?mL/kg), the positive control (Tween 20 5% v/v, 5?mL/kg), and four Schiff base derivative groups named Schiff_1, Schiff_2, Schiff_3, and Schiff_4 (25?mg/kg). After 1?h, all of the groups received ethanol 95% (5?mL/kg) but the normal control received Tween 20 (Tween 20 5% v/v, 5?mL/kg). The animals were euthanized after 60?min and the stomachs were dissected for histology (H&E), immunohistochemistry, and western blot analysis against HSP70 and BAX proteins. The results showed that the Schiff base metal derivatives enhanced the expression of HSP70 and suppressed the expression of BAX proteins during their gastroprotection against ethanol-induced gastric lesion in rats. PMID:24298554

  16. Nitroimidazole and glucosamine conjugated heteroscorpionate ligands and related copper(II) complexes. Syntheses, biological activity and XAS studies.

    PubMed

    Pellei, Maura; Papini, Grazia; Trasatti, Andrea; Giorgetti, Marco; Tonelli, Domenica; Minicucci, Marco; Marzano, Cristina; Gandin, Valentina; Aquilanti, Giuliana; Dolmella, Alessandro; Santini, Carlo

    2011-10-14

    New nitroimidazole and glucosamine conjugated heteroscorpionate ligands, namely 2,2-bis(3,5-dimethyl-1H-pyrazol-1-yl)-N-(2-(2-methyl-5-nitro-1H-imidazol-1-yl)ethyl)acetamide (L(MN)) and 1,3,4,6-tetra-O-acetyl-2-{[bis(3,5-dimethyl-1H-pyrazol-1-yl)acetyl]amino}-2-deoxy-?-D-glucopyranose (L(DAC)), respectively, were synthesized by direct coupling of preformed side chain acid and amine components. The related copper(II) complexes {[(L(MN))(2)Cu]Cl(2)}, and {[(L(DAC))(2)Cu]Cl(2)} have been prepared from the reaction of CuCl(2)*2H(2)O with L(MN) or L(DAC) ligand in methanol solution. Single crystal structural characterization was undertaken for the L(MN) ligand. In the absence of a coordinated metal core, the overall arrangement of the ligand is determined by some loose intra- and inter-molecular nonbonding contacts. X-Ray Absorption Spectroscopy (XAS) has been used to probe the local structure of the two copper(II) complexes, {[(L(MN))(2)Cu]Cl(2)} and {[(L(DAC))(2)Cu]Cl(2)}. The EXAFS analysis has permitted the identification of the local environment of the copper site. Copper interacts with 2 units of ligand in both complexes, and it is found to be 6-fold coordinated. Its local structure is described by four Cu-N and two Cu-O interactions to form a pseudo-octahedron core, with a 0.14 Å lengthening of the Cu-O bond length in the case of L(DAC) complex with respect to the L(MN) one, likely due to the higher steric hindrance of the glucosamine moiety. The XANES analysis agrees with these results, also confirming the Cu(II) formal copper oxidation state for both complexes. The new copper(II) complexes {[(L(MN))(2)Cu]Cl(2)} and {[(L(DAC))(2)Cu]Cl(2)} as well as the corresponding uncoordinated ligands were evaluated for their cytotoxic activity towards a panel of several human tumour cell lines. The results reported here indicate that both copper(II) complexes show similar spectra of cytotoxicity and very low resistance factors (RF < 2) against C13* ovarian cancer cells which have acquired resistance to cisplatin. PMID:21709917

  17. Synthesis, physico-chemical properties and biological analysis of newly obtained copper(II) complexes with pyrazole derivatives.

    PubMed

    Grazul, Magdalena; Besic-Gyenge, Emina; Maake, Caroline; Ciolkowski, Michal; Czyz, Malgorzata; Sigel, Roland K O; Budzisz, Elzbieta

    2014-06-01

    Three new copper(II) complexes containing two different pyrazole bound ligands (1, 2) have been synthesized and characterized by IR, LSI-MS (liquid secondary ion mass spectrometry) and elemental analysis. (1)H NMR spectra of the organic ligands have been recorded. We describe the influence of these complexes on particular cancer cell lines and DNA structure by MTT-assay [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide], APA (acid phosphatase activity)-assay or CD-spectroscopy and agarose gel electrophoresis methods, together with their physico-chemical properties such as lipophilicity and stability in aqueous solution. The cytotoxic effect on HUVEC (endothelial cells) for the most active complex 4 has been also investigated. Moreover, the ability of these complexes to induce apoptosis in cancer cells has been assessed by using fluorescence microscopy. Our results indicate that dichloridobis{1-[amino(thioxo)methyl]-5-hydroxy-3-phenyl-1H-pyrazole-?N2}copper(II) is the most potent complex among the tested complexes. PMID:24662465

  18. Synthesis and spectroscopic properties of novel asymmetric Schiff bases.

    PubMed

    Güngör, Ozlem; Gürkan, Perihan

    2010-09-15

    Three novel diimine Schiff bases including two asymmetric imines (2-OH)R-CHN-C(6)H(4)-CHN-R'(2-OH) type [where R=R'=phenyl for H(2)L(1); R=naphthyl, R'=phenyl for H(2)L(2) and R=R'=naphthyl for H(2)L(3)] have been synthesized with a new two step method. For this purpose, the starting Schiff bases 4-nitrobenzylidene-2-hydroxyaniline (SB(1)-NO(2)) and 4-nitrobenzylidene-2-hydroxy-3-naphthylamine (SB(2)-NO(2)) have been synthesized, previously. Nitro groups of them have been reduced into their amino derivatives (SB(1)-NH(2) and SB(2)-NH(2)) with sodium dithionite as selective reductant and the other imino groups have been formed by adding salicylaldehyde or 2-hydroxy-1-naphthaldehyde to the same solutions. The structures of the diimine Schiff bases were confirmed by elemental analyses, ESI-MS, FT-IR, (1)H NMR and (13)C NMR spectroscopy. The phenol-imine and keto-amine tautomerism of the Schiff bases were investigated by FT-IR, (1)H NMR, (13)C NMR techniques and UV-vis spectra in different solvents (DMSO, methanol, chloroform, toluene and cyclohexane). The effects of acidic and basic media on the tautomeric equilibria were discussed. PMID:20541456

  19. Synthesis and spectroscopic properties of novel asymmetric Schiff bases

    NASA Astrophysics Data System (ADS)

    Güngör, Özlem; Gürkan, Perihan

    2010-09-01

    Three novel diimine Schiff bases including two asymmetric imines (2-OH)R-CH dbnd N-C 6H 4-CH dbnd N-R'(2-OH) type [where R = R' = phenyl for H 2L 1; R = naphthyl, R' = phenyl for H 2L 2 and R = R' = naphthyl for H 2L 3] have been synthesized with a new two step method. For this purpose, the starting Schiff bases 4-nitrobenzylidene-2-hydroxyaniline (SB 1-NO 2) and 4-nitrobenzylidene-2-hydroxy-3-naphthylamine (SB 2-NO 2) have been synthesized, previously. Nitro groups of them have been reduced into their amino derivatives (SB 1-NH 2 and SB 2-NH 2) with sodium dithionite as selective reductant and the other imino groups have been formed by adding salicylaldehyde or 2-hydroxy-1-naphthaldehyde to the same solutions. The structures of the diimine Schiff bases were confirmed by elemental analyses, ESI-MS, FT-IR, 1H NMR and 13C NMR spectroscopy. The phenol-imine and keto-amine tautomerism of the Schiff bases were investigated by FT-IR, 1H NMR, 13C NMR techniques and UV-vis spectra in different solvents (DMSO, methanol, chloroform, toluene and cyclohexane). The effects of acidic and basic media on the tautomeric equilibria were discussed.

  20. Synthesis of novel bisindolylmethane Schiff bases and their antibacterial activity.

    PubMed

    Imran, Syahrul; Taha, Muhammad; Ismail, Nor Hadiani; Khan, Khalid Mohammed; Naz, Farzana; Hussain, Memona; Tauseef, Saima

    2014-01-01

    In an effort to develop new antibacterial drugs, some novel bisindolylmethane derivatives containing Schiff base moieties were prepared and screened for their antibacterial activity. The synthesis of the bisindolylmethane Schiff base derivatives 3-26 was carried out in three steps. First, the nitro group of 3,3'-((4-nitrophenyl)-methylene)bis(1H-indole) (1) was reduced to give the amino substituted bisindolylmethane 2 without affecting the unsaturation of the bisindolylmethane moiety using nickel boride in situ generated. Reduction of compound 1 using various catalysts showed that combination of sodium borohydride and nickel acetate provides the highest yield for compound 2. Bisindolylmethane Schiff base derivatives were synthesized by coupling various benzaldehydes with amino substituted bisindolylmethane 2. All synthesized compounds were characterized by various spectroscopic methods. The bisindolylmethane Schiff base derivatives were evaluated against selected Gram-positive and Gram-negative bacterial strains. Derivatives having halogen and nitro substituent display weak to moderate antibacterial activity against Salmonella typhi, S. paratyphi A and S. paratyphi B. PMID:25102118

  1. Synthesis and Antimicrobial activity of some new Schiff bases

    NASA Astrophysics Data System (ADS)

    G, Karamunge K.; B, Vibhute Y.

    2013-04-01

    New Schiff bases derived from 4iodoaniline, 4-chloroniline, p- toluidine and halogenohydroxy substituted acetophenone have been synthesized. All the compounds have been characterized by IR, H1NMR and mass spectral, halogen, nitrogen analysis. The synthesized compounds have been screened for antimicrobial activity.

  2. Reactivity of dinuclear copper(II) complexes towards melanoma cells: Correlation with its stability, tyrosinase mimicking and nuclease activity.

    PubMed

    Nunes, Cléia Justino; Borges, Beatriz Essenfelder; Nakao, Lia Sumie; Peyroux, Eugénie; Hardré, Renaud; Faure, Bruno; Réglier, Marius; Giorgi, Michel; Prieto, Marcela Bach; Oliveira, Carla Columbano; Da Costa Ferreira, Ana M

    2015-08-01

    In this work, the influence of two new dinuclear copper(II) complexes in the viability of melanoma cells (B16F10 and TM1MNG3) was investigated, with the aim of verifying possible correlations between their cytotoxicity and their structure. One of the complexes had a polydentate dinucleating amine-imine ligand (complex 2), and the other a tridentate imine and a diamine-bridging ligand (complex 4). The analogous mononuclear copper(II) species (complexes 1 and 3, respectively) were also prepared for comparative studies. Crystal structure determination of complex 2 indicated a square-based pyramidal geometry around each copper, coordinated to three N atoms from the ligand and the remaining sites being occupied by either solvent molecules or counter-ions. Complex 4 has a tetragonal geometry. Interactions of these complexes with human albumin protein (HSA) allowed an estimation of their relative stabilities. Complementary studies of their reactivity towards DNA indicated that all of them are able of causing significant oxidative damage, with single and double strand cleavages, in the presence of hydrogen peroxide. However, nuclease activity of the dinuclear species was very similar and much higher than that of the corresponding mononuclear compounds. Although complex 2, with a more flexible structure, exhibits a much higher tyrosinase activity than complex 4, having a more rigid environment around the metal ion, both complexes showed comparable cytotoxicity towards melanoma cells. Corresponding mononuclear complexes showed to be remarkably less reactive as tyrosinase mimics as well as cytotoxic agents. Moreover, the dinuclear complexes showed higher cytotoxicity towards more melanogenic cells. The obtained results indicated that the structure of these species is decisive for its activity towards the malignant tumor cells tested. PMID:26021698

  3. Synthesis, Characterization, and Bioactivity of Schiff Bases and Their Cd2+, Zn2+, Cu2+, and Ni2+ Complexes Derived from Chloroacetophenone Isomers with S-Benzyldithiocarbazate and the X-Ray Crystal Structure of S-Benzyl-?-N-(4-chlorophenyl)methylenedithiocarbazate

    PubMed Central

    Break, Mohammed Khaled bin; Tahir, M. Ibrahim M.; Crouse, Karen A.; Khoo, Teng-Jin

    2013-01-01

    Two bidentate Schiff base ligands having nitrogen sulphur donor sequence were derived from the condensation of S-benzyldithiocarbazate (SBDTC) with 2-chloroacetophenone and 4-chloroacetophenone to give S-benzyl-?-N-(2-chlorophenyl)methylenedithiocarbazate (NS2) and S-benzyl-?-N-(4-chlorophenyl)methylenedithiocarbazate (NS4) isomers. Each of the ligands was then chelated with Cd2+, Zn2+, Cu2+, and Ni2+. The compounds were characterized via IR spectroscopy and melting point while the structure of NS4 was revealed via X-ray crystallography. Finally, the compounds were screened for antimicrobial activity to investigate the effect that is brought by the introduction of the chlorine atom to the benzene ring. X-ray crystallographic analysis showed that the structure of NS4 is planar with a phenyl ring that is nearly perpendicular to the rest of the molecules. The qualitative antimicrobial assay results showed that NS4 and its complexes lacked antifungal activity while Gram-positive bacteria were generally inhibited more strongly than Gram-negative bacteria. Furthermore, NS4 metal complexes were inhibited more strongly than the ligand while the opposite was seen with NS2 ligand and its complexes due to the partial solubility in dimethyl sulfoxide (DMSO). It was concluded that generally NS2 derivatives have higher bioactivity than that of NS4 derivatives and that the Cd complexes of both ligands have pronounced activity specifically on K. rhizophila. PMID:24319401

  4. Synthesis, Characterization and Biological Activity of Cobalt (II), Nickel(II), Copper(II) and Zinc(II) Chloride Complexes with Valeraldehyde Benzoylhydrazone and Valeraldehyde Isonicotinoylhy Drazone

    Microsoft Academic Search

    K. K. Narang; V. P. Singh

    1993-01-01

    Complexes of the title ligands (Schiff bases) viz. valeral-dehyde benzoyl hydra zone, CH3(CH2)3CH = NNHCOC6H5, (VBH), and valeraldehyde isonicotinoylhydrazone, CH3(CH2)3CH = NNHCOC5N, (VINH), of the general composition [ML2C12J xH2O (where M = Co(II), Ni(II), Cu(II) and Zn(II); L = VBH and VINH and x = 0–3) Were prepared and characterized by elemental analyses, infrared, electronic and ESR spectra, magnetic moments,

  5. 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

  6. Spectroscopic studies of bridged binuclear complexes of Co(II), Ni(II), Cu(II) and Zn(II)

    Microsoft Academic Search

    Satish M. Annigeri; M. P. Sathisha; Vidyanand K. Revankar

    2007-01-01

    Binuclear cobalt(II), nickel(II), copper(II) and zinc(II) complexes of general composition [M2L1-2(?-Cl)Cl2] · nH2O with the Schiff-base ligands (where L1H and L2H are the potential pentadentate ligands derived by condensing 2,6-diformyl-4-methylphenol with 4-amino-3-antipyrine and 2-hydroxy-3-hydrazinoquinoxiline,\\u000a respectively) have been synthesized and characterized. Analytical and spectral studies support the above formulation. 1H-NMR and IR spectra of the complexes suggest they have an endogenous

  7. Synthesis, crystal structures and magnetic properties of the copper(II) complexes containing isophthalate anion as coligand

    Microsoft Academic Search

    Feng-Mei Nie; Fei Lu; Jing Chen; Yong-Li Yang

    2009-01-01

    Two new dinuclear isophthalato-bridged copper(II) complexes [Cu2(ntb)2(?-ipt)](ClO4)2·4CH3OH·0.33H2O (1), [Cu2(bbma)2(?-ipt)(NO3)(CH3OH)]NO3·CH3OH (2) and one mononuclear complex [Cu(bbma)(ipt)(CH3OH)0.67(H2O)0.33]·2CH3OH (3) containing tetradentate and tridentate poly-benzimidazole ligands were synthesized, where ntb is tris(2-benzimidazolylmethyl)amine, bbma is bis(benzimidazol-2-yl-methyl)amine and ipt is isophthalate dianion. All of the complexes were characterized by elemental analysis, IR spectra and X-ray crystallography. The structures of complexes 1 and 2 consist of ?-ipt

  8. 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 ?-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 ?M. 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

  9. Copper(II) complexes of methimazole, an anti Grave’s disease drug. Synthesis, characterization and its potential biological behavior as alkaline phosphatase inhibitor

    Microsoft Academic Search

    Nora M. Urquiza; Silvia G. Manca; María A. Moyano; Raquel Arrieta Dellmans; Luis Lezama; Teófilo Rojo; Luciana G. Naso; Patricia A. M. Williams; Evelina G. Ferrer

    2010-01-01

    Methimazole (MeimzH) is an anti-thyroid drug and the first choice for patients with Grave’s disease. Two new copper(II) complexes of this drug:\\u000a [Cu(MeimzH)2(NO3)2].0.5H2O and [Cu(MeimzH)2(H2O)2](NO3)2·H2O were synthesized and characterized by elemental analysis, dissolution behavior, thermogravimetric analysis and UV-vis, diffuse\\u000a reflectance, FTIR and EPR spectroscopies. As it is known that copper(II) cation can act as an inhibitor of alkaline phosphatase\\u000a (ALP),

  10. A new mixed-ligand copper(II) complex of (E)-N";-(2-hydroxybenzylidene) acetohydrazide: Synthesis, characterization, NLO behavior, DFT calculation and biological activities

    NASA Astrophysics Data System (ADS)

    Yousef Ebrahimipour, S.; Sheikhshoaie, Iran; Crochet, Aurelien; Khaleghi, Moj; Fromm, Katharina M.

    2014-08-01

    A tridentate hydrazone Schiff base ligand, (E)-N";-(2-hydroxybenzylidene)acetohydrazide [HL], and its mixed-ligand Cu(II) complex [CuL(phen)], have been synthesized and characterized by elemental analyses, FT-IR, molar conductivity, UV-Vis spectroscopy. The structure of the complex has been determined by X-ray diffraction. This complex has square pyramidal geometry and the positions around central atom are occupied with donor atoms of Schiff base ligand and two nitrogens of 1,10-phenanthroline. Computational studies of compounds were performed by using DFT calculations. The linear polarizabilities and first hyperpolarizabilities of the studied molecules indicate that these compounds can be good candidates of nonlinear optical materials. It is in accordance with experimental data. In addition, invitro antimicrobial results show that these compounds specially [CuL(phen)] have great potential of antibacterial activity against Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Listeria monocytogenes bacteria and antifungal activity against Candida Albicans in comparison to some standard drugs.

  11. Synthesis and spectral characterization of mono- and binuclear copper(II) complexes derived from 2-benzoylpyridine-N?-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, ?=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

  12. Copper(II) complexes with tridentate pyrazole-based ligands: synthesis, characterization, DNA cleavage activity and cytotoxicity.

    PubMed

    Gama, Sofia; Mendes, Filipa; Marques, Fernanda; Santos, Isabel C; Carvalho, M Fernanda; Correia, Isabel; Pessoa, João Costa; Santos, Isabel; Paulo, António

    2011-05-01

    Tridentate pyrazole-containing ligands of the Schiff base type, SalPz - HL(1), Cl(2)SalPz - HL(2) and I(2)SalPz - HL(3), were used to prepare a series of new Cu(II) complexes (CuSalPz - 1, CuCl(2)SalPz - 2 and CuI(2)SalPz - 3). These new complexes have been studied by different analytical techniques (electrospray ionization mass spectrometry (ESI-MS), elemental analysis, FT-IR and EPR). The spectroscopic properties of 1-3 are consistent with the formation of Cu(II) complexes coordinated by monoanionic and tridentate (N,N,O)-chelators, behaving as monomeric species in aqueous solution, as shown by EPR studies. Crystals of 2 and 3, obtained by slow concentration of methanolic solutions of the compounds, were also analyzed by X-ray diffraction analysis. The X-ray structural study has shown that 2 crystallized as a dinuclear compound, [Cu(2)(?-Cl)(2)(Cl(2)SalPz)(2)], while the solid state structure determined for 3 is best described by monomeric units of [CuCl(I(2)SalPz)] displaying short Cu···Cl intermolecular contacts. The in vitro evaluation of 1-3 comprised the study of their DNA-cleaving ability using plasmid DNA and the assessment of their cytotoxic activity against several human cancer cell lines (PC-3 prostate, MCF-7 breast and A2780 and A2780cisR-ovary). The studies with plasmid DNA have shown that 2 and 3 induce extensive DNA cleavage in the presence of different additives. The cytotoxic activity of 2 and 3 is comparable to the one presented by cisplatin, with the exception of the A2780 cell line where cisplatin is more active. It has been found that the introduction of halogen substituents in the phenolate rings of the chelators enhanced the cytotoxicity of the respective Cu(II) complexes. PMID:21450266

  13. Synthesis, spectral, thermal, fluorescence, antimicrobial, anthelmintic and DNA cleavage studies of mononuclear metal chelates of bi-dentate 2H-chromene-2-one Schiff base.

    PubMed

    Prabhakara, Chetan T; Patil, Sangamesh A; Kulkarni, Ajaykumar D; Naik, Vinod H; Manjunatha, M; Kinnal, Shivshankar M; Badami, Prema S

    2015-07-01

    The Co(II), Ni(II) and Cu(II) complexes have been synthesized with Schiff base (HL), derived from 8-formyl-7-hydroxy-4-methylcoumarin with benzylamine. The Schiff base and its metal complexes were structurally characterized based on IR, (1)H NMR, (13)C NMR, UV-visible, ESR, magnetic, thermal, fluorescence, mass and ESI-MS studies. The complexes are completely soluble in DMF and DMSO. The molar conductance values indicate that, all synthesized metal complexes are non-electrolytic in nature. Elemental analysis reveals [ML2(H2O)2] stoichiometry, here MCo(II), Ni(II) and Cu(II), L=deprotonated ligand. The coordination between metal ion and Schiff base was supported by IR data, through deprotonation of phenolic oxygen of coumarin and azomethine nitrogen atoms. Solution electronic spectral results unveiled that all the synthesized complexes posses six coordinated geometry around metal ion. Thermal studies suggest the presence of coordinated water molecules. The Schiff base and its metal complexes have been screened for their antibacterial (Escherichia coli, Pseudomonas aureginosa, Klebsiella pneumoniae and Staphylococcus aureus) and antifungal (Penicillium chrysogenum and Aspergillus niger), anthelmintic (Pheretima posthuma) and DNA cleavage (Calf Thymus DNA) activities. PMID:26002539

  14. Cytotoxic analogs of the iron(III) chelator pyridoxal isonicotinoyl hydrazone: effects of complexation with copper(II), gallium(III), and iron (III) on their antiproliferative activities.

    PubMed Central

    Richardson, D R

    1997-01-01

    This study examined if complexation with metals increased the antiproliferative activities of chelators of the pyridoxal isonicotinoyl hydrazone (PIH) class. Addition of iron(III) to some PIH analogs markedly depressed their activities, whereas it had little effect on others. The gallium(III) complex of PIH, but not its copper(II) complex, was more efficient than the apochelator at inhibiting [3H]thymidine incorporation. PMID:9303419

  15. Coordination behavior of new bis Schiff base ligand derived from 2-furan carboxaldehyde and propane-1,3-diamine. Spectroscopic, thermal, anticancer and antibacterial activity studies

    NASA Astrophysics Data System (ADS)

    Mohamed, Gehad G.; Zayed, Ehab M.; Hindy, Ahmed M. M.

    2015-06-01

    Novel bis Schiff base ligand, [N1,N3-bis(furan-2-ylmethylene)propane-1,3-diamine], was prepared by the condensation of furan-2-carboxaldehyde with propane-1,3-diamine. Its conformational changes on complexation with transition metal ions [Co(II), Ni(II), Cu(II), Mn(II), Cd(II), Zn(II) and Fe(III)] have been studied on the basis of elemental analysis, conductivity measurements, spectral (infrared, 1H NMR, electronic), magnetic and thermogravimetric studies. The conductance data of the complexes revealed their electrolytic nature suggesting them as 1:2 (for bivalent metal ions) and 1:3 (for Fe(III) ion) electrolytes. The complexes were found to have octahedral geometry based on magnetic moment and solid reflectance measurements. Thermal analysis data revealed the decomposition of the complexes in successive steps with the removal of anions, coordinated water and bis Schiff base ligand. The thermodynamic parameters were calculated using Coats-Redfern equation. The Anticancer screening studies were performed on human colorectal cancer (HCT), hepatic cancer (HepG2) and breast cancer (MCF-7) cell lines. The antimicrobial activity of all the compounds was studied against Gram negative (Escherichia coli and Proteus vulgaris) and Gram positive (Bacillus vulgaris and Staphylococcus pyogones) bacteria. It was observed that the coordination of metal ion has a pronounced effect on the microbial activities of the bis Schiff base ligand. All the metal complexes have shown higher antimicrobial effect than the free bis Schiff base ligand.

  16. Synthesis, micellization behavior, antimicrobial and intercalative DNA binding of some novel surfactant copper(II) complexes containing modified phenanthroline ligands.

    PubMed

    Nagaraj, Karuppiah; Ambika, Subramanian; Rajasri, Shanmugasundaram; Sakthinathan, Subramanian; Arunachalam, Sankaralingam

    2014-10-01

    The novel surfactant copper(II) complexes, [Cu(ip)2DA](ClO4)21, [Cu(dpqc)2DA](ClO4)22, [Cu(dppn)2DA](ClO4)23, where ip=imidazo[4,5-f][1,10]phenanthroline, dpqc=dipyrido[3,2-a:2',4'-c](6,7,8,9-tetrahydro)phenazine, dppn=benzo[1]dipyrido[3,2-a':2',3'-c]phenazine and DA-dodecylamine, were synthesized and characterized by physico-chemical and spectroscopic methods. In these complexes 1-3, the geometry of copper metal ions was described as square pyramidal. The critical micelle concentration (CMC) value of these surfactant copper(II) complexes in aqueous solution was found out from conductance measurements. Specific conductivity data at different temperatures served for the evaluation of the temperature-dependent CMC and the thermodynamics of micellization (?Gm°, ?Hm° and ?Sm°). The binding interaction of these complexes with DNA (calf thymus DNA) in Tris buffer was studied by physico-chemical techniques. In the presence of the DNA UV-vis spectrum of complexes showed red shift of the absorption band along with significant hypochromicity indicating intercalation of our complexes with nucleic acids. Competitive binding study with ethidium bromide (EB) shows that the complexes exhibit the ability to displace the nucleic acid-bound EB indicating that the complexes bind to nucleic acids in strong competition with EB for the intercalative binding site. Observed changes in the circular dichoric spectra of DNA in the presence of surfactant complexes support the strong binding of complexes with DNA. CV results also confirm this mode of binding. Some significant thermodynamic parameters of the binding of the titled complexes to DNA have also been determined. The results reveal that the extent of DNA binding of 3 was greater than that of 1 and 2. The antibacterial and antifungal screening tests of these complexes have shown good results compared to its precursor chloride complexes. PMID:25033435

  17. 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.

  18. Preparation and antibacterial activity of Schiff bases from O -carboxymethyl chitosan and para -substituted benzaldehydes

    Microsoft Academic Search

    Xueqiong YinJunhua; Junhua Chen; Wen Yuan; Qiang Lin; Li Ji; Fang Liu

    Seven Schiff bases were synthesized from O-carboxymethyl chitosan (CMC) and para-substituted benzaldehydes. The Schiff bases were characterized through Fourier Transform Infrared Spectroscopy, Carbon-13\\u000a Nuclear Magnetic Resonance (13C NMR), Distortionless Enhancement of Polarization Transfer (DEPT) 135 NMR, elemental analysis, and acid–base titration. Antibacterial\\u000a activities of the Schiff bases against Escherichia coli (E. coli, ATCC 35218) and Staphylococcus aureus (S. aureus, ATCC

  19. Sonochemical synthesis of two new copper(II) complexes with azo ligands derived from anthranilic acid and ?-naphtol.

    PubMed

    Hojaghani, Shiva; Sadr, Moayed Hosaini; Morsali, Ali

    2015-09-01

    Nanostructures of two new copper(II) complexes, (CuL1), 0.5EtOH. 1.5H2O (1), [H2L1=5-(4-Carboxy phenyl azo) anthranilic acid], (Cu(L2)2) (2), [HL2=1-(4-Carboxy phenyl azo) 2-naphtol] have been synthesized by the reaction of H2L1 and HL2 with Cu(OAc)2 · H2O through sonochemical process. Calcination of the nano-sized compounds 1-2 yield CuO nanoparticles at 550-450°C under air atmosphere. Metallic copper nanoparticles were prepared by direct calcination of compound 2 in surfactant at 180°C. These nanostructures were characterized by X-ray powder diffraction (XRD) and Scanning Electron Microscopy (SEM). Thermal stability of compounds 1-2 was studied by thermal gravimetric (TG) and differential thermal analyses (DTA). PMID:25835614

  20. Structural and spectral studies of copper(II) and nickel(II) complexes of pyruvaldehyde mixed bis{N(4)-substituted thiosemicarbazones}

    Microsoft Academic Search

    Lily J. Ackerman; Phillip E. Fanwick; Mark A. Green; Elizabeth John; William E. Running; John K. Swearingen; James W. Webb; Douglas X. West

    1999-01-01

    Pyruvaldehyde mixed bis(thiosemicarbazones) have been prepared in which the two thiosemicarbazone moieties have different N(4)-substituents. The mixed bis(thiosemicarbazones) and their copper(II) and nickel(II) complexes have been characterized with IR, electronic, mass, 1H NMR (Ni) and EPR (Cu) spectra. Representative crystal structures have been solved of nickel(II) complexes with either a pyruvaldehyde mixed bis(thiosemicarbazone) or a bis(thiosemicarbazone) with identical N(4)-substituents acting

  1. Synthesis, crystal structure and magnetic behavior of a two-dimensional copper(II) complex with mellitic anion as bridging ligand

    Microsoft Academic Search

    Ming-Gen Zhao; Cheng-Qi Liu; Jing-Min Shi; Wei Xu

    2003-01-01

    A two-dimensional complex Cu3[C6(COO)6](H2O)10 · 2H2O has been prepared and its crystal structure determined by X-ray crystallography. In the complex each mellitic anion provides four carboxylate groups as coordinate groups and, according to the coordination, the four carboxylate groups are classified as two types according to its coordinate modes. The first is that a carboxylate group coordinates a copper(II) ion

  2. Distinctive EPR signals provide an understanding of the affinity of bis-(3-hydroxy-4-pyridinonato) copper(II) complexes for hydrophobic environments.

    PubMed

    Rangel, Maria; Leite, Andreia; Silva, André M N; Moniz, Tânia; Nunes, Ana; Amorim, M João; Queirós, Carla; Cunha-Silva, Luís; Gameiro, Paula; Burgess, John

    2014-07-01

    In this work we report the synthesis and characterization of a set of 3-hydroxy-4-pyridinone copper(ii) complexes with variable lipophilicity. EPR spectroscopy was used to characterize the structure of copper(ii) complexes in solution, and as a tool to gain insight into solvent interactions. EPR spectra of solutions of the [CuL2] complexes recorded in different solvents reveal the presence of two copper species whose ratio depends on the nature of the solvent. Investigation of EPR spectra in the pure solvents methanol, dimethylsulfoxide, dichloromethane and their 50% (v/v) mixtures with toluene allowed the characterization of two types of copper signals (gzz = 2.30 and gzz = 2.26) whose spin-Hamiltonian parameters are consistent with solvated and non-solvated square-planar copper(ii) complexes. Regarding the potential biological application of ligands and complexes and to get insight into the partition properties in water-membrane interfaces, EPR spectra were also obtained in water-saturated octanol, an aqueous solution buffered at pH = 7.4 and liposome suspensions, for three compounds representative of different hydro-lipophilic balances. Analysis of the EPR spectra obtained in liposomes allowed establishment of the location of the complexes in the water and lipid phases. In view of the results of this work we put forward the use of EPR spectroscopy to assess the affinity of copper(ii) complexes for a hydrophobic environment and also to obtain indirect information about the lipophilicity of the ligands and similar EPR silent complexes. PMID:24834987

  3. Synthesis, Characterization and Biological Studies of Metal(II) Complexes of (3E)-3-[(2-{(E)-[1-(2,4-Dihydroxyphenyl) ethylidene]amino}ethyl)imino]-1-phenylbutan-1-one Schiff Base.

    PubMed

    Ejidike, Ikechukwu P; Ajibade, Peter A

    2015-01-01

    Co(II), Ni(II), Zn(II) and Cu(II) complexes of (3E)-3-[(2-{(E)-[1-(2,4-dihydroxyphenyl)ethylidene]amino}ethyl)imino]-1-phenylbutan-1-one (DEPH2) derived from ethylenediamine, 2',4'-dihydroxyacetophenone and 1-phenylbutane-1,3-dione have been synthesized and characterized by elemental analysis, FTIR, UV-Visible spectroscopy, and screened to establish their potential as antibacterial agents, antioxidants and DPPH radical scavengers. The FTIR spectra showed that the ligand behaves as a dibasic tetradentate ligand with the dioxygen-dinitrogen donor atom system oriented towards the central metal ion. The analytical and spectroscopic data suggest a square planar geometry for Cu(II) and Ni(II) complexes and an octahedral geometry for the Co(II) complex. The ligand and their metal complexes were screened for antibacterial activity against Gram (+) and Gram (-) bacteria by the agar well diffusion method. In addition, the antioxidant activities of the complexes were also investigated through their scavenging effect on DPPH and ABTS radicals. The obtained IC50 value of the DPPH activity for the copper complex (2.08 ± 0.47 µM) and that of the ABTS activity for the copper complex (IC50 = 2.11 + 1.69 µM) were higher than the values obtained for the other compounds. PMID:26023939

  4. Supramolecular control of a mononuclear biomimetic copper(II) center: bowl complexes vs funnel complexes.

    PubMed

    Gout, Jérôme; Višnjevac, Aleksandar; Rat, Stéphanie; Parrot, Arnaud; Hessani, Assia; Bistri, Olivia; Le Poul, Nicolas; Le Mest, Yves; Reinaud, Olivia

    2014-06-16

    Modeling the mononuclear site of copper enzymes is important for a better understanding of the factors controlling the reactivity of the metal center. A major difficulty stems from the difficult control of the nuclearity while maintaining free sites open to coordination of exogenous ligands. A supramolecular approach consists in associating a hydrophobic cavity to a tripodal ligand that will define the coordination spheres as well as access to the metal ion. Here, we describe the synthesis of a bowl Cu(II) complex based on the resorcinarene scaffold. This study supplements a previous work on Cu(I) coordination. It provides a complete picture of the cavity-copper system in its two oxidation states. The first XRD structure of such a bowl complex was obtained, evidencing a 5-coordinate Cu(II) ion with the three imidazole donors bound to the metal (two in the base of the pyramid, one in the apical position) and with an acetate anion, completing the base of the pyramid, and deeply included in the bowl. Solution studies conducted by EPR and UV-vis absorption spectroscopies as well as cyclic voltammetry highlighted interaction with coordinating solvents, various carboxylates that can sit either in the endo or in the exo position depending on their size as well as possible stabilization of hydroxo species in a mononuclear state. A comparison of the binding and redox properties of the bowl complex with funnel complexes based on the calix[6]arene core further highlights the importance of supramolecular features defining the first, second, and third coordination sphere for control of the metal ion. PMID:24901070

  5. XAFS Study of the Ferro- and Antiferromagnetic Binuclear Copper(II) Complexes of Azomethine Based Tridentate Ligands

    SciTech Connect

    Vlasenko, Valery G. [Institute of Physics, Rostov State University, Stachki Ave., 194, 344090, Rostov-on-Don (Russian Federation); Institute of Physical and Organic Chemistry, Rostov State University, Stachki Ave., 194/2, 344090, Rostov-on-Don (Russian Federation); Vasilchenko, Igor S.; Shestakova, Tatiana E.; Uraev, Ali I.; Burlov, Anatolii S.; Garnovskii, Alexander D. [Institute of Physical and Organic Chemistry, Rostov State University, Stachki Ave., 194/2, 344090, Rostov-on-Don (Russian Federation); Pirog, Irina V. [Institute of Physics, Rostov State University, Stachki Ave., 194, 344090, Rostov-on-Don (Russian Federation)

    2007-02-02

    Binuclear copper complexes are known to be models for metalloenzymes containing copper active sites, and some of them are of considerable interest due to their magnetic and charge transfer properties. The reactions of the complex formation of bibasic tridentate heterocyclic imines with copper acetate leads to two types of chelates with mono deprotonated ligands and with totally deprotonated ligands. Cu K-edge EXAFS has been applied to determine the local structure around the metal center in copper(II) azomethine complexes with five tridentate ligands: 1-(salycilideneimino)- or 1-(2-tosylaminobenzilideneimino)-2-amino(oxo, thio)benzimidazoles. It has been found that some of the chelates studied are bridged binuclear copper complexes, and others are mononuclear complexes. The copper-copper interatomic distances in the bridged binuclear copper complexes were found to be 2.85-3.01 A. Variable temperature magnetic susceptibility data indicate the presence of both ferromagnetic and antiferromagnetic interactions within the dimer, the former is dominating at low temperatures and the latter at high temperatures.

  6. Synthesis, Characterization, Antioxidant, and Antibacterial Studies of Some Metal(II) Complexes of Tetradentate Schiff Base Ligand: (4E)-4-[(2-{(E)-[1-(2,4-Dihydroxyphenyl)ethylidene]amino}ethyl)imino]pentan-2-one

    PubMed Central

    Ejidike, Ikechukwu P.; Ajibade, Peter A.

    2015-01-01

    Co(II), Ni(II), Cu(II), and Zn(II) complexes of (4E)-4-[(2-{(E)-[1-(2,4-dihydroxyphenyl)ethylidene]amino}ethyl)imino]pentan-2-one have been synthesized and characterized by elemental analyses, molar conductance, electronic and IR spectral studies, and XRD. FTIR confirmed the ligand coordinates the metal ion to form mononuclear complex via the oxygen and nitrogen atoms of the phenolic group and azomethine group, respectively. Tetrahedral geometry is proposed for Co(II) complex and square-planar geometry for Ni(II) and Cu(II) complexes. The antibacterial studies of the compounds were determined and they show that the metal complexes are more active than the free ligands. The antioxidant activity by DPPH and ABTS method was examined and it shows Cu(II); IC50 = 2.31 ± 1.54?µM for DPPH and Co(II); IC50 = 1.83 ± 1.08?µM for ABTS were the most active.

  7. 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. [Laquipai, Porto (Portugal). Faculdade de Ciencias do Porto; Cabral, J.P.S. [Inst. de Botanica e Centro de Citologia Experimental U.P., Porto (Portugal)

    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.

  8. Temperature-dependent self-assembly of near-infrared (NIR) luminescent Zn2Ln and Zn2Ln3 (Ln = Nd, Yb or Er) complexes from the flexible Salen-type Schiff-base ligand

    NASA Astrophysics Data System (ADS)

    Miao, Tiezheng; Zhang, Zhao; Feng, Weixu; Su, Peiyang; Feng, Heini; Lü, Xingqiang; Fan, Daidi; Wong, Wai-Kwok; Jones, Richard A.; Su, Chengyong

    2014-11-01

    Through the self-assembly of the precursor [Zn(L)(MeCN)] (H2L = N,N?-bis(3-methoxy-salicylidene)cyclohexane-1,2-diamine) with LnCl3·6H2O (Ln = La, Nd, Yb, Er or Gd) and NaN3 in alcohol-containing solutions, two series of mixed anions-induced Zn2Ln-arrayed complexes [Zn2(L)2(MeOH)ClLn(N3)]·Cl (Ln = La, 1; Ln = Nd, 2; Ln = Yb, 3; Ln = Er, 4 or Ln = Gd, 5) and Zn2Ln3-arrayed complexes [Zn2(L)3Cl2(?2-OH)(?3-OH)2Ln3(N3)2] (Ln = La, 6; Ln = Nd, 7; Ln = Yb, 8; Ln = Er, 9 or Ln = Gd, 10) are obtained at room temperature or under reflux, respectively. In contrast to Zn2Ln-arrayed complexes with the two Zn2+ ions in the inner cis-N2O2 cores and one Ln3+ ion in the outer O2O2 moieties, the demetalation of partial precursors leads to the selective exchange of Zn2+ centers for the Ln3+ ions for the formation of novel heterometallic Zn2Ln3-arrayed complexes with the Ln3+ ions in both the inner cis-N2O2 core and the outer O2O2 moieties of the ligands. The result of their photophysical properties shows that the characteristic near-infrared (NIR) luminescence of Nd3+ or Yb3+ ion has been sensitized from the excited state (both 1LC and 3LC) of the ligand H2L, while relatively lower quantum yields for Zn2Ln3-arrayed complexes than those for Zn2Ln-arrayed complexes, correspondingly, should be due to the luminescent quenching with the involvement of OH- oscillators around the Ln3+ ions.

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

    SciTech Connect

    Milacic, Vesna; Chen Di [Prevention Program, Barbara Ann Karmanos Cancer Institute, Department of Pathology, School of Medicine, Wayne State University, Detroit, Michigan (United States); Giovagnini, Lorena [Department of Chemical Sciences, University of Padova, via Marzolo 1, 35131 Padova (Italy); Diez, Alejandro [Department of Internal Medicine, Wayne State University, Detroit, Michigan (United States); Fregona, Dolores [Department of Chemical Sciences, University of Padova, via Marzolo 1, 35131 Padova (Italy); Dou, Q. Ping [Prevention Program, Barbara Ann Karmanos Cancer Institute, Department of Pathology, School of Medicine, Wayne State University, Detroit, Michigan (United States)], E-mail: doup@karmanos.org

    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.

  10. Synthesis and structural characterization of 1,2-bis((1 H-pyrrol-2-yl)methylene)hydrazine and its Cu(II) complex

    NASA Astrophysics Data System (ADS)

    Zhang, Guoqi; Yang, Lanying; Ma, Jinshi; Yang, Guoqiang

    2011-12-01

    The hydrogen-bonding potential and complexation behavior with copper(II) of a multidentate Schiff-base ligand, 1,2-bis((1 H-pyrrol-2-yl)methylene)hydrazine (H 2L) was studied. Crystallization of H 2L from an aqueous methanol solution resulted in the formation of an adduct H 2L·H 2O, which features a two-dimensional (2D) supramolecular hydrogen-bonded network, as evidenced by X-ray structural analysis. The reaction of H 2L with copper(II) salt in a CH 2Cl 2sbnd MeOH solution formed a dinuclear double-stranded helicate, Cu 2( L) 2 ( 1) in high yield, which was characterized by microanalysis, IR spectra, and single-crystal X-ray crystallographic analysis. UV-vis titration experiments confirmed the spontaneous formation of a 1:1 metal-ligand complex in solution.

  11. 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.

  12. X-ray absorption spectral studies of copper(II) mixed ligand complexes having ethylenediamine as one of the ligands

    NASA Astrophysics Data System (ADS)

    Dwivedi, Shikha; Joshi, S. K.; Hinge, V. K.; Shrivastava, B. D.; Prasad, J.; Srivastava, K.

    2014-09-01

    X-ray absorption spectra of copper(II) mixed ligand complexes, having ethylenediamine (en) as one of the ligands, have been recorded at the K-edge of copper at the dispersive extended X- ray absorption fine structure (EXAFS) beamline (BL-8) at the 2.5 GeV INDUS-2 Synchrotron, RRCAT, Indore, India. The samples studied are: Cu(en)2(ClO4)2, Cu(en)2Br2.H2O and Cu(en)2SO4. The data obtained has been processed using EXAFS data analysis program Athena. The K-edge has been found to split in two edges K and K' in each of the complex. The energies of the edges K(EK) and K'(EK') and the principal absorption maximum A(EA) have been determined from the derivative spectra. The chemical shift has been utilized to determine the oxidation state of copper in the complexes and to estimate effective nuclear charge (ENC) on the absorbing atom. The EXAFS data has been used to determine the bond lengths in the complexes using three different graphical methods. The bond lengths, obtained from one of these methods and the Fourier transformation method, are comparable with each other, showing that both of these methods give phase uncorrected bond lengths.

  13. Studies on the mixed-ligand complexes of copper(II) with gallic acid and pyridine carboxylic acids and their benzologues

    Microsoft Academic Search

    M. S. Abu-Bakr; H. M. Rageh; E. Y. Hashem; M. H. Moustafa

    1994-01-01

    The ternary complex formation of copper(II) with gallic acid (gal) and 2-hydroxy nicotinic acid (hyna), 2-mercapto nicotinic acid (mena), salicylic acid (sa) or thiosalicylic acid (tsa) as a second ligand in a 1:1:1 molar ratio has been investigated in 40% (v\\/v) ethanol using spectrophotometric andpH titration methods. The solution equilibria of the ternary systems have been determined and the stability

  14. Vibrational study of copper(II) complexes with triaza and trithia macrocycles: [9]aneN3, [9]aneS3 and [6]aneS3

    NASA Astrophysics Data System (ADS)

    Diaz Fleming, G.; Campos Vallette, M. M.; Clavijo, E.; Diez, S.; Saavedra, M.

    1999-08-01

    The infrared spectra of the triaza and trithia macrocycles [9]aneN3, [9]aneS3 and [6]aneS3, and their corresponding copper(II) complexes have been recorded in the region 120-4000 cm -1. A vibrational assignment was performed on the basis of well documented data and complemented in some cases with a normal coordinate analysis. Reflectance IR spectra obtained from a smooth copper surface were analyzed searching for a possible surface effect.

  15. Tuning the cytotoxic properties of new ruthenium(III) and ruthenium(II) complexes with a modified bis(arylimino)pyridine Schiff base ligand using bidentate pyridine-based ligands.

    PubMed

    Garza-Ortiz, Ariadna; Maheswari, Palanisamy Uma; Lutz, Martin; Siegler, Maxime A; Reedijk, Jan

    2014-06-01

    Synthesis, spectroscopy, characterization, structures, and cytotoxicity studies of 2,6-bis(2,6-diisopropylphenyliminomethyl)pyridine (LLL) ruthenium compounds are described. The starting compound [RuCl3(LLL)] has been fully characterized using IR spectroscopy, UV-vis spectroscopy, electrospray ionization mass spectrometry, and NMR spectroscopy. In addition, the crystal structure of the ligand LLL has been determined using single-crystal X-ray diffraction. With the ruthenium(III) trichloride compound as starting material, a new family of Ru(II) complexes with a number of neutral and charged bidentate co-ligands have been synthesized and used for characterization and cytotoxicity studies. The synthesis of the corresponding [Ru(II)LLL(LL)Cl](+/0) complexes with co-ligands- LL is 1,10-phenanthroline, 2,2'-bipyridyl, 2-(phenylazo)pyridine, 2-(phenylazo)-3-methylpyridine, 2-(tolylazo)pyridine, or the anionic 2-picolinate-is reported. Analytical, spectroscopic (IR spectroscopy, UV-vis spectroscopy, (1)H NMR spectroscopy, and electrospray ionization mass spectrometry), and structural characterization of the new compounds is described. Crystal structure analyses of two Ru(II) compounds show a slightly distorted octahedral Ru(II) geometry with tridentate LLL coordinated in a planar meridional fashion, and the chelating co-ligand (LL) and a chloride ion complete the octahedron. The co-ligand plays a significant role in modulating the physicochemical and cytotoxic properties of these new ruthenium complexes. The in vitro cytotoxicity of these new Ru(II) complexes (half-maximal inhibitory concentration, IC50, of 0.5-1.5 ?M), in comparison with the parent Ru(III) compound (half-maximal inhibitory concentration of 3.9-4.3 ?M) is higher for several of the human cancer cell lines tested. The cytotoxic activity of some of the new ruthenium compounds is even higher than that of cisplatin in the same cancer cell lines. The cytotoxicity of these new anticancer compounds is discussed in the light of structure-based activity relationships, and a possible mechanism of action is suggested. PMID:24430199

  16. Targeted inhibition of Snail family zinc finger transcription factors by oligonucleotide-Co(III) Schiff base conjugate

    PubMed Central

    Harney, Allison S.; Lee, Jiyoun; Manus, Lisa M.; Wang, Peijiao; Ballweg, David M.; LaBonne, Carole; Meade, Thomas J.

    2009-01-01

    A transition metal complex targeted for the inhibition of a subset of zinc finger transcription factors has been synthesized and tested in Xenopus laevis. A Co(III) Schiff base complex modified with a 17-bp DNA sequence is designed to selectively inhibit Snail family transcription factors. The oligonucleotide-conjugated Co(III) complex prevents Slug, Snail, and Sip1 from binding their DNA targets whereas other transcription factors are still able to interact with their target DNA. The attachment of the oligonucleotide to the Co(III) complex increases specificity 150-fold over the unconjugated complex. Studies demonstrate that neither the oligo, or the Co(III) Schiff base complex alone, are sufficient for inactivation of Slug at concentrations that the conjugated complex mediates inhibition. Slug, Snail, and Sip1 have been implicated in the regulation of epithelial-to-mesenchymal transition in development and cancer. A complex targeted to inactivate their transcriptional activity could prove valuable as an experimental tool and a cancer therapeutic. PMID:19666616

  17. In vitro cytotoxicity, DNA cleavage and SOD-mimic activity of copper(II) mixed-ligand quinolinonato complexes.

    PubMed

    Buchtík, Roman; Trávní?ek, Zden?k; Van?o, 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 ?M (HOS), and 1.3 ± 0.5 ?M (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 ?M, 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

  18. Vanadium(IV) and copper(II) complexes of salicylaldimines and aromatic heterocycles: Cytotoxicity, DNA binding and DNA cleavage properties.

    PubMed

    Correia, Isabel; Roy, Somnath; Matos, Cristina P; Borovic, Sladjana; Butenko, Nataliya; Cavaco, Isabel; Marques, Fernanda; Lorenzo, Julia; Rodríguez, Alejandra; Moreno, Virtudes; Pessoa, João Costa

    2015-06-01

    Five copper(II) complexes, [Cu(sal-Gly)(bipy)](1), [Cu(sal-Gly)(phen)] (2), [Cu(sal-l-Ala)(phen)] (3), [Cu(sal-D-Ala)(phen)] (4), [Cu(sal-l-Phe)(phen)] (5) and five oxidovanadium(IV) complexes, [V(IV)O(sal-Gly)(bipy)] (6), [V(IV)O(sal-Gly)(phen)] (7), [V(IV)O(sal-l-Phe)(H2O)] (8), [V(IV)O(sal-l-Phe)(bipy)] (9), [V(IV)O(sal-l-Phe)(phen)] (10) (sal=salicylaldehyde, bipy=2,2'-bipyridine, phen=1,10-phenanthroline) were synthesized and characterized, and their interaction with DNA was evaluated by different techniques: gel electrophoresis, fluorescence, UV-visible and circular dichroism spectroscopy. The complexes interact with calf-thymus DNA and efficiently cleave plasmid DNA in the absence (only 2 and 5) and/or presence of additives. The cleavage ability is concentration-dependent as well as metal and ligand-dependent. Moreover, DNA binding experiments show that the phen-containing Cu(II) and V(IV)O compounds display stronger DNA interaction ability than the corresponding bipy analogues. The complexes present cytotoxic activity against human ovarian (A2780) and breast (MCF7) carcinoma cells. Cell-growth inhibition (IC50) of compounds 1, 2 and 5 in human promyelocytic leukemia (HL60) and human cervical cancer (HeLa) cells were also determined. The copper complexes show much higher cytotoxic activity than the corresponding vanadium complexes and the reference drug cisplatin (except for the sal-Gly complexes); namely, the phenanthroline copper complexes 2-5 are ca. 10-fold more cytotoxic than cisplatin and more cytotoxic than their bipyridine analogues. PMID:25858461

  19. 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

  20. 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, E-mail: wangxiuli@bhu.edu.cn [Department of Chemistry, Bohai University, Liaoning Province Silicon Materials Engineering Technology Research Centre, Jinzhou 121000 (China)] [Department of Chemistry, Bohai University, Liaoning Province Silicon Materials Engineering Technology Research Centre, Jinzhou 121000 (China); Zhao, Wei; Zhang, Ju-Wen; Lu, Qi-Lin [Department of Chemistry, Bohai University, Liaoning Province Silicon Materials Engineering Technology Research Centre, Jinzhou 121000 (China)] [Department of Chemistry, Bohai University, Liaoning Province Silicon Materials Engineering Technology Research Centre, Jinzhou 121000 (China)

    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 title complexes. Black-Right-Pointing-Pointer Magnetic properties and electrochemical behaviors have been reported.

  1. Discrete trinuclear copper(II) compounds as building blocks: the influence of the peripheral substituents on the magnetic coupling in oxamato-bridged complexes.

    PubMed

    Barros, Wdeson P; da Silva, Beatriz C; Reis, Natália V; Pereira, Cynthia L M; Doriguetto, Antônio C; Cano, Joan; Pirota, Kleber R; Pedroso, Emerson F; Julve, Miguel; Stumpf, Humberto O

    2014-10-21

    Two new trinuclear copper(ii) complexes without end-capping ligands, (Bu4N)2[Cu(dmso)2{Cu(dnopba)(dmso)}2] () and (Bu4N)2[Cu(dmso)2{Cu(dcopba)(dmso)}2] () [dnopba = 4,5-dinitro-ortho-phenylenebis(oxamate), dcopba = 4,5-dichloro-ortho-phenylenebis(oxamate), Bu4N(+) = tetra-n-butylammonium and dmso = dimethylsulfoxide], were synthesized and their structures were determined by single crystal X-ray diffraction. The crystal structures of and consist of two outer bis(oxamato)(dmso)cuprate(ii) units which act as bidentate ligands toward a trans-bis(dmso)copper(ii) inner entity leading to centrosymmetric tricopper(ii) complexes with copper-copper separations across the oxamate bridges of 5.1916(3) () and 5.1776(3) Å (). The peripheral copper(ii) ions in and are five-coordinate in somewhat distorted square pyramidal environments with a dmso molecule filling the apical position whereas the inner copper(ii) ion is six-coordinate in an elongated octahedral environment with two dmso molecules in the axial sites. The investigation of their magnetic properties in the temperature range 2.0-300 K shows the occurrence of a strong intramolecular antiferromagnetic coupling between the copper(ii) ions through the oxamate bridges [J1 = -296(1) () and -334(1) cm(-1) (), the Hamiltonian being defined as ? = -J1(?Cu2·?Cu1 + ?Cu2·?Cu1')], which leads to a low-lying spin doublet at low temperatures. Density functional theory calculations (DFT) have been used to substantiate these magnetic couplings and also to analyse the influence exerted on these interactions by the type of substituent at the 4,5-positions from the phenylene ring of the bis(oxamate) ligand. PMID:25135421

  2. Synthesis, spectroscopic properties, crystal structure and biological activities of copper(II) 2-methylthionicotinate complexes with furopyridines

    Microsoft Academic Search

    Peter Segl’a; Jozef Miklovi?; Dušan Mikloš; Viera Mrázová; Lenka Krupková; Daniela Hudecová; Zuzana Ondrušová; Jozef Švorec; Ján Moncol; Milan Melník

    2009-01-01

    The synthesis and characterization of six new 2-methylthionicotinate (2-MeSnic) copper(II) monomeric complexes [Cu(2-MeSnic)2L2] (L is furo[3,2-c]pyridine—fpy, 2-methylfuro[3,2-c]pyridine—Mefpy, 2,3-dimethylfuro[3,2-c]pyridine—Me2fpy or benzo[4,5]furo[3,2-c]pyridine—Bfp), [Cu(2-MeSnic)2(fpy)2(H2O)], as well as [Cu(2-MeSnic)2(CF3Phfpy)2(H2O)2] (CF3Phfpy is 2-(3-trifluoromethylphenyl)furo[3,2-c]pyridine) are reported. The characterizations were based on elemental analysis,\\u000a infrared, electronic and EPR spectra. The crystal structure of one of the complexes has been determined. The CuII atoms of [Cu(2-MeSnic)2(fpy)2(H2O)] are six-coordinated

  3. Synthesis, Crystal Structures, and Antibacterial Activity of Copper(II) and Cobalt(III) Complexes Derived from 2-{1-[2-(2-Hydroxyethylamino)ethylimino]ethyl}phenol

    Microsoft Academic Search

    Zhi-Xi Hang; Bo Dong; Xing-Wen Wang

    2011-01-01

    A new copper(II) complex [Cu(HEP)(N3)] (1), and a new cobalt(III) complex [Co(HEP)(AE)]·Cl·H2O (2), where HEP is 2-{1-[2-(2-hydroxyethylamino)ethylimino]ethyl}phenolate, AE is 2-(2-aminoethylamino)ethanol, were prepared and characterized by elemental analysis, IR spectra, and single crystal X-ray diffraction. Complex (1) crystallizes in the monoclinic space group P21\\/c with unit cell dimensions 9.969(3) Å, 19.218(3) Å, 7.272(2) Å, = 108.788(3), 1319.0(6) Å, 4, 0.0424 and

  4. Manganese(II), iron(II), cobalt(II), and copper(II) complexes of an extended inherently chiral tris-bipyridyl cage

    PubMed Central

    Perkins, David F.; Lindoy, Leonard F.; McAuley, Alexander; Meehan, George V.; Turner, Peter

    2006-01-01

    Manganese(II), iron(II), cobalt(II), and copper(II) derivatives of two inherently chiral, Tris(bipyridyl) cages (L and L?) of type [ML]-(PF6)2(solvent)n and [FeL?](ClO4)2 are reported, where L is the hexa-tertiary butyl-substituted derivative of L?. These products were obtained by using the free cage and metal template procedures; the latter involved the reductive amination of the respective Tris-dialdehyde precursor complexes of iron(II), cobalt(II), or nickel(II). Electrochemical, EPR, and NMR studies have been used to probe the nature of the individual complexes. X-ray structures of the manganese(II), iron(II), and copper(II) complexes of L and the iron(II) complex of L? are presented; these are compared with the previously reported structures of the corresponding nickel(II) complex and metal-free cage (L). In each complex the metal cation occupies the cage's central cavity and is coordinated to six nitrogens from the three bipyridyl groups. The cations [MnL]2+ and [FeL]2+ are isostructural but both exhibit a different arrangement of the bound cage to that observed in the corresponding nickel(II) and copper(II) complexes. The latter have an exo-exo arrangement of the bridgehead nitrogen lone pairs, with the metal inducing a triple helical twist that extends ?22 Å along the axial length of each complex. In contrast, [MnL]2+ and [FeL]2+ have their terminal nitrogen lone pairs directed endo, causing a significant change in the configuration of the bound ligand. In [FeL?]2+, the cage has both bridgehead nitrogen lone pairs orientated exo. Semiempirical calculations indicate that the observed endo-endo and exo-exo arrangements are of comparable energy. PMID:16407129

  5. Chemical mechanism of dioxygen activation by manganese(III) Schiff base compound in the presence of aliphatic aldehydes

    Microsoft Academic Search

    Miyuki Suzuki; Takashi Ishikawa; Akihiko Harada; Shigeru Ohba; Masatomi Sakamoto; Yuzo Nishida

    1997-01-01

    The manganese(III) complexes with tetradentate Schiff base [H2(L)] derived from salicylaldehyde and 2-amino-1-benzylamine [abbreviated as H2(salabza)], ethylenedimaine and 2-hydroxybenzophenone [H2(7-Phe-salen)], ethylenediamine and 2-hydroxyacetophenone [H2(7-Me-salen)] showed much higher activity for degradation of tetraphenylcyclopentadienone(TCPN) the singlet oxygen (1?g) scavenger, in the presence of cyclohexanecarboxaldehyde than those of the compounds with H2(salen) and H2(salphen), which are derived from salicyaldehyde and ethylenediamine, and o-phenylenediamine,

  6. A new Schiff base based on vanillin and naphthalimide as a fluorescent probe for Ag+ in aqueous solution

    NASA Astrophysics Data System (ADS)

    Zhou, Yanmei; Zhou, Hua; Ma, Tongsen; Zhang, Junli; Niu, Jingyang

    2012-03-01

    A new Schiff base based on vanillin and naphthalimide was designed and synthesized as fluorescent probe. The probe showed high selectivity for Ag+ over other metal ions such as Pb2+, Na+, K+, Cd2+, Ba2+, Cr3+, Zn2+, Cu2+, Ni2+, Ca2+, Al3+ and Mg2+ in aqueous solution. A new fluorescence emission was observed at 682 nm in the presence of Ag+ ion. The fluorescence intensity quenched with increasing the concentration of Ag+ at 682 nm. The method of job's plot confirmed the 1:2 complex between Ag+ and probe, and the mechanism was proposed.

  7. Tunable emissive lanthanidomesogen derived from a room-temperature liquid-crystalline Schiff-base ligand.

    PubMed

    Pramanik, Harun A R; Das, Gobinda; Bhattacharjee, Chira R; Paul, Pradip C; Mondal, Paritosh; Prasad, S Krishna; Rao, D S Shankar

    2013-09-23

    A novel photoluminescent room-temperature liquid-crystalline salicylaldimine Schiff base with a short alkoxy substituent and a series of lanthanide(III) complexes of the type [Ln(LH)3(NO3)3] (Ln = La, Pr, Sm, Gd, Tb, Dy; LH = (E)-5-(hexyloxy)-2-[{2-(2-hydroxyethylamino)ethylimino]methyl}phenol) have been synthesized and characterized by FTIR, (1)H and (13)C?NMR, UV/Vis, and FAB-MS analyses. The ligand coordinates to the metal ions in its zwitterionic form. The thermal behavior of the compounds was investigated by polarizing optical microscopy (POM) and differential scanning calorimetry (DSC). The ligand exhibits an enantiotropic hexagonal columnar (Col(h)) mesophase at room temperature and the complexes show an enantiotropic lamellar columnar (Col(L)) phase at around 120?°C with high thermal stability. Based on XRD results, different space-filling models have been proposed for the ligand and complexes to account for the columnar mesomorphism. The ligand exhibits intense blue emission both in solution and in the condensed state. The most intense emissions were observed for the samarium and terbium complexes, with the samarium complex glowing with a bright-orange light (ca. 560-644?nm) and the terbium complex emitting green light (ca. 490-622?nm) upon UV irradiation. DFT calculations performed by using the DMol3 program at the BLYP/DNP level of theory revealed a nine-coordinate structure for the lanthanide complexes. PMID:23939837

  8. Investigation on some Schiff bases as HCl corrosion inhibitors for carbon steel

    Microsoft Academic Search

    A. Yurt; A. Balaban; S. Ustün Kandemir; G. Bereket; B. Erk

    2004-01-01

    Potentiodynamic polarisation and ac impedance studies were carried out on the inhibition of carbon steel in 0.1M hydrochloric acid solution by various Schiff bases containing heteroaromatic substituents. The examined Schiff bases were 2-((1E)-2-aza-2-pyrimidine-2-ylvinyl)thiophene, 2-((1Z)-1-aza-2-(2-pyridyl)vinyl)pyrimidine, 2-((1E)-2-aza-2-(1,3-thiazol-2-yl)vinyl)thiophene, 2-((1Z)-1-aza-2-(2-thienyl)vinyl)benzothiazole. Polarisation curves indicates that studied Schiff bases act essentially as anodic inhibitor. The variation in inhibitive efficiency mainly depends on the type and nature

  9. 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

  10. Diverse structures and adsorption properties of quasi-Werner-type copper(II) complexes with flexible and polar axial bonds.

    PubMed

    Noro, Shin-ichiro; Ohba, Tomonori; Fukuhara, Katsuo; Takahashi, Yukiko; Akutagawa, Tomoyuki; Nakamura, Takayoshi

    2011-03-14

    The quasi-Werner-type copper(II) complex, [Cu(PF(6))(2)(4-mepy)(4)] (1), in which 4-mepy is the 4-methylpyridine ligand, has flexible and polar axial bonds of Cu-PF(6). Flexibility of the Cu-PF(6) bonds induces diverse and unprecedented guest-inclusion structures, such as {[Cu(PF(6))(2)(4-mepy)(4)][Cu(PF(6))(4-mepy)(4)(acetone)]·PF(6)·4acetone} (?-1?2.5acetone), {[Cu(PF(6))(2)(4-mepy)(4)][Cu(PF(6))(4-mepy)(4)(2-butanone)]·PF(6)·3.5(2-butanone)} (?-1?2.25(2-butanone)), {[Cu(PF(6))(2)(4-mepy)(4)][Cu(PF(6))(4-mepy)(4)(H(2)O)]·PF(6)·4benzene} (?-1?0.5H(2)O·2benzene), and {[Cu(PF(6))(2)(4-mepy)(4)]·2benzene} (?-1?2benzene). Exposure of the dense form, ?-1, to benzene vapor affords the benzene-inclusion complex {[Cu(PF(6))(2)(4-mepy)(4)]·2benzene} (?-1?2benzene), all benzene guests of which are easily removed by vacuum drying, reforming guest-free, dense ?-1' with smaller sized crystals than ?-1. In contrast to ?-1, which shows almost no CO(2) adsorption, ?-1' adsorbs CO(2) gas with structural transformations, this being the first example that exhibits adsorption of gas in a dense Werner-type complex and a drastic change in adsorption properties depending on the size of the crystals. PMID:21258723

  11. The role of a Schiff base scaffold, N-(2-hydroxy acetophenone) glycinate-in overcoming multidrug resistance in cancer.

    PubMed

    Ganguly, Avishek; Chakraborty, Paramita; Banerjee, Kaushik; Choudhuri, Soumitra Kumar

    2014-01-23

    Drug resistance is a problem that hinders the numerous successes of chemotherapeutic intervention of cancer and continues to be a major obstacle for cures. Till date, several attempts have been made to develop suitable multidrug resistance (MDR) reversing agents. But, throughout the clinical development of MDR reversing agents, patients repeatedly suffer from toxicities. So far, some anticancer activity of Schiff bases which are the condensation products of carbonyl compounds and primary amines and their metal complexes has been described. But, overcoming multidrug resistance, by the use of such small molecules still remain unexplored. Under this backdrop, in search of less toxic and more effective MDR reversing agents our laboratory has developed the different metal chelates of Schiff base N-(2-hydroxy acetophenone)glycinate (NG) which is structurally similar to azatyrosine [L-?-(5-hydroxy-2-pyridyl)-alanine] that inhibits tumor formation by deactivating the c-Raf-1 kinase and c-Ha-ras signalling pathway. A decade-long research proposes possible strategies to overcome MDR by exploiting the chemical nature of such metal chelates. In this review we have catalogued the success of metal chelates of NG to overcome MDR in cancer. The review depict that the problem of MDR can be circumvent by synchronized activation of immunogenic cell death pathways that utilize the components of a host's immune system to kill cancer cells in combination with other conventional strategies. The current wealth of preclinical information promises better understanding of the cellular processes underlying MDR reversing activity of metal derivatives of NG and thus exposes several cellular targets for rational designing of new generation of Schiff base metal chelates as MDR reversing agents. PMID:24044945

  12. Cerium(III)-Catalyzed Synthesis of Schiff Bases: A Green Approach

    Microsoft Academic Search

    Lakshmy Ravishankar; Siddhartha A. Patwe; Nehal Gosarani; Aparajita Roy

    2010-01-01

    The reaction of primary aromatic amines with aryl aldehydes is found to be catalyzed by cerium chloride heptahydrate under solvent-free conditions to give the corresponding Schiff bases in good yields.

  13. Electric-field-induced Schiff-base deprotonation in D85N mutant bacteriorhodopsin.

    PubMed Central

    Kolodner, P; Lukashev, E P; Ching, Y C; Rousseau, D L

    1996-01-01

    The application of an external electric field to dry films of Asp-85-->Asn mutant bacteriorhodopsin causes deprotonation of the Schiff base, resulting in a shift of the optical absorption maximum from 600 nm to 400 nm. This is in marked contrast to the case of wild-type bacteriorhodopsin films, in which electric fields produce a red-shifted product whose optical properties are similar to those of the acid-blue form of the protein. This difference is due to the much weaker binding of the Schiff-base proton in the mutant protein, as indicated by its low pK of approximately 9, as compared with the value pK approximately 13 in the wild type. Other bacteriorhodopsins with lowered Schiff-base pK values should also exhibit a field-induced shift in the protonation equilibrium of the Schiff base. We propose mechanisms to account for these observations. PMID:8876185

  14. 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 ?g mL-1. Complexes also exhibit SOD-like activity with their IC50 values ranging from 0.717 to 1.848 ?M.

  15. The effect of some Schiff bases on the corrosion of aluminum in hydrochloric acid solution

    NASA Astrophysics Data System (ADS)

    Ashassi-Sorkhabi, H.; Shabani, B.; Aligholipour, B.; Seifzadeh, D.

    2006-04-01

    The inhibition effect of Schiff bases benzylidene-(2-methoxy-phenyl)-amine (A), (2-methoxy-phenyl)-(4-methyl-benzylidene)-amine (B), (4-chloro-benzylidene)-(2-methoxy-phenyl)-amine (C) and (4-nitro-bezylidene)-(2-methoxy-phenyl)-amine (D) on the corrosion of aluminum in 1 M HCl has been studied by polarization, electrochemical impedance spectroscopy (EIS) and weight loss measurements. It has been found that all the studied Schiff bases are excellent inhibitors. Maximum inhibition was obtained for 0.01 M Schiff base A. Results show that the inhibition efficiency increases with decreasing in temperature and increasing in concentration of Schiff base. Polarization curves reveal that the used inhibitors are mixed type inhibitors. The surface adsorption of the Schiff bases leads to a decrease of double layer capacitance as well as an increase of polarization resistance. The inhibitor performance depends strongly on the type of function groups substituted on benzene ring. The adsorption of used compounds on the aluminum surface obeys a Langmuir isotherm and has a physical mechanism. Thermodynamic parameters for both dissolution and adsorption processes were determined. The quantum chemical study of the corrosion inhibition efficiency of the Schiff bases on Al in molar HCl was carried out.

  16. Synthesis, characterization and antibacterial activity of biodegradable films prepared from Schiff bases of zein.

    PubMed

    Soliman, E A; Khalil, A A; Deraz, S F; El-Fawal, G; Elrahman, S Abd

    2014-10-01

    Pure zein is known to be very hydrophobic, but is still inappropriate for coating and film applications because of their brittle nature. In an attempt to improve the flexibility and the antimicrobial activity of these coatings and films, Chemical modification of zein through forming Schiff bases with different phenolic aldhydes was tried. Influence of this modifications on mechanical, topographical, wetting properties and antimicrobial activity of zein films were evaluated. The chemical structure of the Schiff bases films were characterized by ATR-FTIR spectroscopy. The results indicate an improvement in mechanical properties with chemically modification of zein to form Schiff bases leading to a reduction in the elastic modulus. An increase in the elongation at break has been observed, but with slight influence on tensile strength. Plasticized zein films have similar initial contact angle (?40°). An increase in reaction temperature and time increases film's affinity towards water. As shown by contact angle measurements, a noticeable relation was found between film composition and the hydrophilicity. Surface topography also varied by forming Schiff bases, becoming rougher than zein-based films. The antibacterial activities of zein and Schiff bases of zein-based films were investigated against gram-positive bacteria (Listeria innocua, Listeria monocytogenes, Bacillus cereus and Clostridium sporogenes) and gram-negative bacteria (Escherichia coli, Yersinia enterocolitica and Salmonella enterica). It was found that the antibacterial activity of the Schiff bases-based films was more effective than that of zein-based films. PMID:25328181

  17. 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.

  18. Syntheses, structural, magnetic, and electron paramagnetic resonance studies of monobridged cyanide and azide dinuclear copper(II) complexes: antiferromagnetic superexchange interactions.

    PubMed

    Reger, Daniel L; Pascui, Andrea E; Smith, Mark D; Jezierska, Julia; Ozarowski, Andrew

    2015-02-16

    The reactions of Cu(ClO4)2 with NaCN and the ditopic ligands m-bis[bis(1-pyrazolyl)methyl]benzene (Lm) or m-bis[bis(3,5-dimethyl-1-pyrazolyl)methyl]benzene (Lm*) yield [Cu2(?-CN)(?-Lm)2](ClO4)3 (1) and [Cu2(?-CN)(?-Lm*)2](ClO4)3 (3). In both, the cyanide ligand is linearly bridged (?-1,2) leading to a separation of the two copper(II) ions of ca. 5 Å. The geometry around copper(II) in these complexes is distorted trigonal bipyramidal with the cyanide group in an equatorial position. The reaction of [Cu2(?-F)(?-Lm)2](ClO4)3 and (CH3)3SiN3 yields [Cu2(?-N3)(?-Lm)2](ClO4)3 (2), where the azide adopts end-on (?-1,1) coordination with a Cu-N-Cu angle of 138.0° and a distorted square pyramidal geometry about the copper(II) ions. Similar chemistry in the more sterically hindered Lm* system yielded only the coordination polymer [Cu2(?-Lm*)(?-N3)2(N3)2]. Attempts to prepare a dinuclear complex with a bridging iodide yield the copper(I) complex [Cu5(?-I4)(?-Lm*)2]I3. The complexes 1 and 3 show strong antiferromagnetic coupling, -J = 135 and 161 cm(-1), respectively. Electron paramagnetic resonance (EPR) studies coupled with density functional theory (DFT) calculations show that the exchange interaction is transmitted through the dz(2) and the bridging ligand s and px orbitals. High field EPR studies confirmed the dz(2) ground state of the copper(II) ions. Single-crystal high-field EPR has been able to definitively show that the signs of D and E are positive. The zero-field splitting is dominated by the anisotropic exchange interactions. Complex 2 has -J = 223 cm(-1) and DFT calculations indicate a predominantly d(x(2)-y(2)) ground state. PMID:25602445

  19. Kinetics and mechanism of the oxidation of (. cap alpha. -hydroxyalkyl)chromium complexes by copper(II) and iron(III) ions

    SciTech Connect

    Bakac, A.; Espenson, J.H.

    1981-05-20

    Copper(II) and iron(III) ions react with (..cap alpha..-hydroxyalkyl)chromium(2+) complexes (alkyl = methyl, ethyl, 2-propyl) in water or in aqueous alcohol solutions leading to the cleavage of the chromium-carbon bond. The immediate products are Cr/sup 2 +/, the reduced metal ion (Cu/sup +/ or Fe/sup 2 +/), and the corresponding aldehyde or ketone. The reactions obey the rate law -d(CrROH/sup 2 +/)/dt = (k + k'(H)/sup -1/(CrROH/sup 2 +/)(M), where M = Cu/sup 2 +/ or Fe/sup 3 +/. The dominant k' term has the following values in 1 M aqueous parent alcohol (methanol, ethanol, and 2-propanol, respectively): CrCH/sub 2/OH/sup 2 +/, k'/sub Cu/ = 0.251 s/sup -1/,k'/sub Fe/ = 0.496 s/sup -1/; CrCH(CH/sub 3/)OH/sup 2 +/, 1.46, 0.481; CrC(CH/sub 3/)/sub 2/OH/sup 2 +/, 0.574, 1.90. The reactivity toward Cu/sup 2 +/ and Fe/sup 3 +/ is significantly diminished upon substitution of the OH hydrogen by an alkyl group. Copper(II) does not react with (..cap alpha..-alkoxyalkyl)chromium(2+) complexes at all, while iron(III) shows some reactivity with k'/sub Fe/ = 0.0127 s/sup -1/ (CrCH/sub 2/OCH/sub 3//sup 2 +/) and 0.0400 s/sup -1/ (CrCH(CH/sub 3/)OC/sub 2/H/sub 5//sup 2 +/), both in 1 M methanol. A mechanism proposed for the oxidation of (..cap alpha..-hydroxyalkyl)chromium(2+) complexes by copper(II) and iron(III) consists of the oxidant attack at the alcoholic OH group followed by a slow electron-transfer step.

  20. Ternary copper(II) complexes of levofloxacin and phenanthroline derivatives: in-vitro antibacterial, DNA interactions, and SOD-like activity.

    PubMed

    Patel, M N; Parmar, Pradhuman Amrutsinh; Gandhi, Deepen Sureshbhai; Thakkar, Vasudev R

    2011-06-01

    A series of ternary copper(II) complexes have been derived using levofloxacin and five phenanthroline derivatives. Complexes were characterized using infrared spectroscopy, Thermogravimetric (TG)-analysis, fast atom bombardment mass spectroscopy and reflectance spectra. Synthesized complexes exhibit the only d-d band at ? 666?nm points toward a distorted square pyramidal geometry at metal centre with one unpaired electron responsible for paramagnetic behaviour of whole moiety. Binding behaviour of the complexes toward Herring Sperm DNA were determined using ultraviolet-Vis (UV-Vis) absorption titration and viscometric titration experiment, where as the cleavage efficacy of the complexes toward pUC19 DNA was determined by electrophoresis in presence of ethidium bromide. Complexes exhibit superoxide dismutase-like activity with their IC(50) values ranging from 0.7917 to 1.7432 µM. PMID:21271865

  1. 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.

  2. Structure and thermal properties of volatile copper(II) complexes with ?-diimine derivatives of acetylacetone and the structure of 2-(methylamino)-4-(methylimino)-pentene-2 crystals

    Microsoft Academic Search

    N. B. Morozova; P. A. Stabnikov; I. A. Baidina; P. P. Semyannikov; S. V. Trubin; I. K. Igumenov

    2007-01-01

    Copper(II) chelates with ?-diimine derivatives of acetylacetone that have a general formula of Cu(R1C(NR2)CHC(NR2)R1)2, where R1, R2 are alkyl substituents, are synthesized. The complexes were identified using elemental analysis, melting point measurements,\\u000a and high-temperature mass spectrometry data. Knudsen technique is employed to determine the vapor pressure temperature dependence,\\u000a and standard thermodynamic parameters of sublimation ?H\\u000a \\u000a T\\u000a 0\\u000a and ?S\\u000a \\u000a T

  3. Reappraisal of the amide coordination mode: solution properties of nickel(II) and copper(II) complexes of ligands involving simultaneously enamine and amide groups

    SciTech Connect

    Costes, J.P.; Laurent, J.P.

    1988-09-07

    The behavior of the Cu/sup 2+//L/sub 1/ system in solution was reappraised through the isolation and characterization of the copper(II) complexes involving the ligand L/sub 1/ in different states of protonation. Also included in the study are the homologous nickel(II) complexes and the copper(II) and nickel(II) complexes of related ligands L/sub 2/ and L/sub 3/. L/sub 1/ is the ligand 3,8-dimethyl-4,7-diazadeca-2,8-diene-1,10-diamide synthesized from acetoacetamide and 1,2,diaminoethane. L/sub 2/ and L/sub 3/ were similarly synthesized using acetoacetanilide and ethylacetoacetate instead of acetoamide. The complexes were studied by ESR and visible spectroscopy, and the data demonstrate that in all cases not only the ligand L/sub 3/ but also L/sub 1/ and L/sub 2/ are in the enamine form, and the first step of the protonation process concerns the proton of the enamine functions and not those of the amide group. 8 references, 2 tables.

  4. Synthesis and crystal structure of a new copper(II) complex with N,N?-(4,4?-bithiazole-2,2?-diyl)diacetimidamide as ligand: Molecular docking, DNA-binding and cytotoxicity activity studies

    NASA Astrophysics Data System (ADS)

    Wang, Ling-Dong; Zheng, Kang; Li, Yan-Tuan; Wu, Zhi-Yong; Yan, Cui-Wei

    2013-04-01

    A new mononuclear copper(II) complex with formula of [Cu2H(DABTA)2](pic)?6H2O, where H2DABTA and pic- stand for N,N'-(4,4'-bithiazole-2,2'-diyl)diacetimidamide and picrate ion, respectively, has been synthesized and characterized by elemental analysis, molar conductivity measurement, IR and electronic spectra studies, and single-crystal X-ray diffraction. The crystal structure reveals that the copper(II) ion has a {CuN4} square-planar coordination environment. The solvent water molecules form a column parallel to c axis by hydrogen bonds. Then the mononuclear copper complexes link to the water columns to make a three-dimensional hydrogen bonding grid with the cavities filled by pic- anions. Besides, there are offset ?-? stacking interactions between thiazole rings in the supramolecular system. The interactions between the copper(II) complex and herring sperm DNA (HS-DNA) have been investigated by using electronic absorption titration, fluorescence titration and viscometry. The molecular docking of the complex with the self-complementary DNA duplex of sequence d(ACCGACGTCGGT)2 demonstrates that the complex is stabilized by additional electrostatic and hydrogen bonding interaction with the DNA. The copper(II) complex exhibits potent anticancer activities against human hepatocellular carcinoma cell SMMC-7721 and human lung adenocarcinoma cell A549.

  5. Interaction of drug based copper(II) complexes with Herring Sperm DNA and their biological activities

    NASA Astrophysics Data System (ADS)

    Patel, Mohan N.; Patel, Chintan R.; Joshi, Hardik N.

    2012-11-01

    Square pyramidal Cu(II) complexes with NS donor ligand and ciprofloxacin have been synthesized and characterized using analytical and spectral techniques. The synthesized complexes have been tested for their antimicrobial activity using double dilution technique in terms of minimum inhibitory concentration (MIC) and colony forming unit (CFU). The DNA binding ability of the complexes with Sperm Herring DNA has been performed using absorption titration and viscosity measurement. The nuclease activity of complexes with plasmid DNA (pUC19) has been carried out using agarose gel electrophoresis technique. Synthesized complexes have been tested for their SOD mimic activity using NBT/NADH/PMS system. The cytotoxic properties of metal complexes have been evaluated using brine shrimp lethality bioassay.

  6. Synthesis and antitumor mechanisms of a copper(ii) complex of anthracene-9-imidazoline hydrazone (9-AIH).

    PubMed

    Qin, Qi-Pin; Liu, Yan-Cheng; Wang, Hai-Lu; Qin, Jiao-Lan; Cheng, Feng-Jie; Tang, Shang-Feng; Liang, Hong

    2015-07-01

    A new anthracycline derivative, anthracene-9-imidazoline hydrazone (9-AIH), was synthesized and selected as an antitumor ligand to afford a copper(ii) complex of 9-AIH, cis-[Cu(II)Cl2(9-AIH)] (). Complex was structurally characterized by IR, elemental analysis, ESI-MS and single crystal X-ray diffraction analysis. By MTT assay, it was revealed that showed overall a higher in vitro cytotoxicity than 9-AIH towards a panel of human tumour cell lines, with IC50 values from 0.94-3.68 ?M, in which the BEL-7404 cell line was the most sensitive to . By spectral analyses and gel electrophoresis, the DNA binding affinity of 9-AIH and was determined. 9-AIH was suggested to bind with DNA in an intercalative mode, with a quenching constant of 1.04 × 10(4) M(-1) on the EB-DNA complex. While for , both intercalative and covalent binding modes were suggested. By flow cytometry, was found to block the cell cycle of BEL-7404 cells in a dose-dependent mode, in which it induced the G2/M phase arrest at 0.5 ?M and induced the S phase arrest at higher concentrations of 1.0 or 2.0 ?M. From the cellular morphological observations under different fluorescence probe staining, a dose-dependent manner of to induce cell apoptosis in the late stage was suggested. Comparatively, equivalent apoptotic cells, respectively, in the early and late stages were found when incubated with 2.0 ?M of 9-AIH. The mitochondrial membrane potential measured by JC-1 staining and the ROS generation in cells detected using a DCFH-DA probe suggested that the cell apoptosis induced by might undergo the ROS-related mitochondrial pathway. Accordingly, the mutant p53 expression was found to be suppressed and the caspase cascade (caspase-9/3) was consequently activated by . This action mechanism for in the BEL-7404 cells was unique and was not found in the presence of 9-AIH under the same conditions, indicating their different antitumor mechanism. Furthermore, the in vivo acute toxicity of tested on mice indicated that should be a high cytotoxic antitumor agent, with the LD50 value in the range of 32-45 mg kg(-1), which is much higher than that of 9-AIH. From the above results, the central Cu(ii) of in the coordinated mode with 9-AIH was believed to play a key role in exerting both the high cytotoxicity and the effective antitumor mechanism. PMID:25904543

  7. Hydroxyquinoline derived vanadium(IV and V) and copper(II) complexes as potential anti-tuberculosis and anti-tumor agents.

    PubMed

    Correia, Isabel; Adão, Pedro; Roy, Somnath; Wahba, Mohamed; Matos, Cristina; Maurya, Mannar R; Marques, Fernanda; Pavan, Fernando R; Leite, Clarice Q F; Avecilla, Fernando; Costa Pessoa, João

    2014-12-01

    Several mixed ligand vanadium and copper complexes were synthesized containing 8-hydroxyquinoline (8HQ) and a ligand such as picolinato (pic(-)), dipicolinato (dipic(2-)) or a Schiff base. The complexes were characterized by spectroscopic techniques and by single-crystal X-ray diffraction in the case of [V(V)O(L-pheolnaph-im)(5-Cl-8HQ)] and [V(V)O(OMe)(8HQ)2], which evidenced the distorted octahedral geometry of the complexes. The electronic absorption data showed the presence of strong ligand to metal charge transfer bands, significant solvent effects, and methoxido species in methanol, which was further confirmed by (51)V-NMR spectroscopy. The structures of [Cu(II)(dipic)(8HQ)]Na and [V(IV)O(pic)(8HQ)] were confirmed by EPR spectroscopy, showing only one species in solution. The biological activity of the compounds was assessed through the minimal inhibitory concentration (MIC) of the compounds against Mycobacterium tuberculosis (Mtb) and the cytotoxic activity against the cisplatin sensitive/resistant ovarian cells A2780/A2780cisR and the non-tumorigenic HEK cells (IC50 values). Almost all tested vanadium complexes were very active against Mtb and the MICs were comparable to, or better than, the MICs of drugs, such as streptomycin. The activity of the complexes against the A2780 cell line was dependent on incubation time presenting IC50 values in the 3-14 ?M (at 48 h) range. In these conditions, the complexes were significantly (*P<0.05-**P<0.001) more active than cisplatin (22 ?M), in the A2780 cells and even surpassing its activity in the cisplatin-resistant cells A2780cisR (2.4-8 ?M vs. 75.4; **P<0.001). In the non-tumorigenic HEK cells poor selectivity toward cancer cells for most of the complexes was observed, as well as for cisplatin. PMID:25226436

  8. Mono and dinuclear copper(II) complexes of 2,4,6-tris(2-pyridyl)-1, 3,5-triazine and halide or pseudohalide ions: Synthesis and spectral studies

    Microsoft Academic Search

    José V. Folgado; Emilio Escrivá; Aurelio Beltrán-Porter; Daniel Beltrán-Porter

    1986-01-01

    Summary By inhibiting the copper(II) assisted TPT (TPT = 2,4,6-tris(2-pyridyl)-1,3,5-triazine) hydrolysis, monomeric and dimeric copper(II) complexes having as general formulae Cu(TPT)X, · nH2O (X = Cl, Br, NCS, NCO or N3) and [Cu(TPT)X]2(PF6)2 · nH2O (X = Cl, Br, NCS or N3) have been synthesized and characterized by i.r., electronic and e.p.r. spectra, x-ray powder diffraction and analytical data. Spectroscopic

  9. 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-?S)methylidene]amino}imino-?N)ethyl]pyridin-2-yl-?N}ethylidene)-1-cyanohydrazinido-?N(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

  10. 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]?3Cl?3H2O] has been described. X-ray studies shows that the trinuclear complex crystallizes as [{Cu3(L1)3Cl3}2?6Cl?13CH3CN?2H2O] 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 ?-?* 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.

  11. The synthesis and characterization of copper(II)– p -aminosalicylate complexes with diamine ligands

    Microsoft Academic Search

    Murat Ta?; Seval Çamur; Yalç?n K?l?ç

    2011-01-01

    The complexes were synthesized by the reaction between sodium salt of p-aminosalicylic acid (PAS) and Cu(II) for 1 and corresponding ethylenediamine (en) or its derivatives for 2–6. The complexes were characterized by using elemental analyses, FT-IR, UV–Vis, magnetic moment measurements, and thermal analyses\\u000a techniques. In complex 1[Cu2(PA)4(H2O)2], two Cu(II) ions were found as bridged by four ?-O:O? p-aminosalicylato (PA) ligands,

  12. Oxo Transfer from Nitrogen Dioxide to Nitrito Group in a Copper(II) Complex.

    PubMed

    Gogoi, Kuldeep; Deka, Hemanta; Kumar, Vikash; Mondal, Biplab

    2015-05-18

    Reaction of Cu(II) complex [Cu(II)(LH)(O2CCH3)2] (1) [LH = 4,6-ditert-butyl-2-((2-picolyl(isopropyl)amino)methyl)phenol] with equivalent amount of NO2 leads to the reduction of Cu(II) to Cu(I) with concomitant nitration at the phenol ring of the ligand. This resulted in the in situ formation of intermediate Cu(I) complex of the nitrated ligand (L'H). Additional equivalent of NO2 coordinates to the Cu(I) complex to form corresponding O-nitrito Cu(II) complex [Cu(II)(L'(?(1)-ONO)] (2). Subsequent addition of NO2 led to the corresponding O-nitrato complex, [Cu(II)(L')(?(1)-ONO2)] (3) with concomitant formation of NO. Complexes 2 and 3 were isolated and structurally characterized. The formation of NO in the reaction was established by spin-trapping experiment. Isotopic labeling experiment revealed that the oxo transfer takes place from NO2 to the coordinated ?(1)-ONO group. PMID:25928428

  13. Copper(II) complexes of alloferon 1 with point mutations (H1A) and (H9A) stability structure and biological activity.

    PubMed

    Matusiak, Agnieszka; Kuczer, Mariola; Czarniewska, El?bieta; Rosi?ski, Grzegorz; Kowalik-Jankowska, Teresa

    2014-09-01

    Mono- and polynuclear copper(II) complexes of the alloferon 1 with point mutations (H1A) A(1)GVSGH(6)GQH(9)GVH(12)G (Allo1A) and (H9A) H(1)GVSGH(6)GQA(9)GVH(12)G (Allo9A) have been studied by potentiometric, UV-visible, CD, EPR spectroscopic and mass spectrometry (MS) methods. To obtain a complete complex speciation different metal-to-ligand molar ratios ranging from 1:1 to 4:1 for Allo1A and to 3:1 for Allo9A were studied. The presence of the His residue in first position of the peptide chain changes the coordination abilities of the Allo9A peptide in comparison to that of the Allo1A. Imidazole-N3 atom of N-terminal His residue of the Allo9A peptide forms stable 6-membered chelate with the terminal amino group. Furthermore, the presence of two additional histidine residues in the Allo9A peptide (H(6),H(12)) leads to the formation of the CuL complex with 4N {NH2,NIm-H(1),NIm-H(6),NIm-H(12)} binding site in wide pH range (5-8). For the Cu(II)-Allo1A system, the results demonstrated that at physiological pH7.4 the predominant complex the CuH-1L consists of the 3N {NH2,N(-),CO,NIm} coordination mode. The inductions of phenoloxidase activity and apoptosis in vivo in Tenebrio molitor cells by the ligands and their copper(II) complexes at pH7.4 were studied. The Allo1A, Allo1K peptides and their copper(II) complexes displayed the lowest hemocytotoxic activity while the most active was the Cu(II)-Allo9A complex formed at pH7.4. The results may suggest that the N-terminal-His(1) and His(6) residues may be more important for their proapoptotic properties in insects than those at positions 9 and 12 in the peptide chain. PMID:24935092

  14. Copper(II) complexes with pyrazole derivatives - Synthesis, crystal structure, DFT calculations and cytotoxic activity

    NASA Astrophysics Data System (ADS)

    Kupcewicz, Bogumi?a; Ciolkowski, Michal; Karwowski, Boleslaw T.; Rozalski, Marek; Krajewska, Urszula; Lorenz, Ingo-Peter; Mayer, Peter; Budzisz, Elzbieta

    2013-11-01

    The series of pyrazole derivatives (1a-4a) were used as bidentate N,N' ligands to obtain neutral Cu(II) complexes of ML2Cl2 type (1b-4b). The molecular structures of ligand 1a and Cu(II) complex 4b were determined by X-ray crystallography and theoretical DFT calculations. In this study, three functionals B3LYP, BP86 and mPW1PW91 with different basis sets and two effective core potentials Los Alamos and Stuttgart/Dresden were performed. The DFT study disclosed the usefulness of BP86 functional with SDD-ECP for Cu(II) ion and dedicated D95 basis set for other non-transition metal atoms, with the exclusion of Cl for which 6-31++G(2df,2pd) were used. The structural analysis shows that the presence of phenyl substituent in a pyrazole ring contributed to Cu-N bond elongation, which can result in different reactivity of complexes 1b and 3b. The cytotoxicity of the obtained compounds was evaluated on three cancer cells lines: HL-60, NALM-6 and WM-115. The complexes have exhibited similar moderate antiproliferative activity. All the complexes, except for 1b, were found to be more active against three cancer cell lines than uncomplexed pyrazoles. The lipophilicity and electrochemical properties of ligands and complexes was also studied. For complexes with ligand 1a and 3a only one reduction process at the metal centre occurs (Cu(II) ? Cu(I)) with oxidization of Cu(I)-Cu(II) in the backward step.

  15. 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 ?/( P, ?) ? d x2-y2 ligand-to-metal charge transfer (LMCT) transition, together with partial d ? d ligand field (LF) transition.

  16. A new copper(II) complex with 2-thenoyltrifluoroacetone and 2,2-bipyridine: Crystal structure, spectral properties and cytotoxic activity

    NASA Astrophysics Data System (ADS)

    Lopes, P. S.; Paixão, D. A.; de Paula, F. C. S.; Ferreira, A. M. D. C.; Ellena, J.; Guilardi, S.; Pereira-Maia, E. C.; Guerra, W.

    2013-02-01

    This work reports the synthesis and characterization of a new copper(II) complex with 2-thenoyltrifluoroacetone (HTTA) and 2,2-bipyridine (bipy). The complex was characterized by elemental analysis, UV-Vis, IR and EPR. The crystal structure was determined by single-crystal X-ray diffraction. The copper ion has a distorted square-pyramidal geometry and is coordinated to two bidentate ligands (HTTA and bipy) and a perchlorate ion weakly bonded in the apical position. The crystal packing is stabilized by non-classical hydrogen bonds and weak interactions ?-? stacking. In the copper complex, the metal ion binds to HTTA via the oxygen atoms of the ?-diketone group and to bipy via its two heterocyclic nitrogens. The title compound inhibits the growth of K562 cells with an IC50 value equal to 28.2 ?mol L-1.

  17. C{sub 2}-symmetric Copper(II) complexes as chiral Lewis acids

    SciTech Connect

    Evans, D.A.; Murry, J.A.; Matt, P. von [Harvard Univ., Cambridge, MA (United States)] [and others

    1995-12-01

    Two new Cu(II)-derived Lewis acid catalysts 1 and 2 have been prepared and their utility as catalysts in the Diels-Alder reaction documented. While complex 1 is effective in catalyzing the cycloaddition of unsaturated aldehyde dienophiles with cyclopentadiene complex 2 is optimal for imide dienophiles. This study provides a rational basis for the design of Lewis acids based on the coordinating capacity of cationic Cu(II) complexes which possess sufficient Lewis acidity to catalyze a range of synthetically useful Diels-Alder reactions. In particular, documentation of the importance of counterion structure in the use of cationic metal centers as Lewis acids has been made for the first time.

  18. Novel Copper(II) Complexes of N -Phenylanthranilic Acid Containing Ethanol and Hydroxo Ligands

    Microsoft Academic Search

    Murat Ta?; Okan Zafer Ye?ilel; Orhan Büyükgüngör

    2010-01-01

    The complexes, tetra-?-[2-(phenylamino)benzoato](O,O?)-bis[(ethanol)copper(II)] (1) and di-?-[2-(phenylamino)benzoato](O,O?)-bis[(hydroxo)copper(II)]\\u000a (2), were synthesized by the reaction of N-phenylanthranilic acid and CuCl2·2H2O in an ethanol water mixture. In complex 1, each Cu(II) atom, which is in a slightly distorted square pyramidal environment, is coordinated equatorially by four N-phenylanthranilate O-atoms and axially by the ethanol O-atoms. In complex 2, [Cu2(C6H5NHC6H4COO)2(OH)2], each Cu(II) atom, which is in

  19. Solvation-induced helicity inversion of pseudotetrahedral chiral copper(II) complexes.

    PubMed

    Chamayou, Anne-Christine; Makhloufi, Gamall; Nafie, Laurence A; Janiak, Christoph; Lüdeke, Steffen

    2015-03-01

    The helicity of four-coordinated nonplanar complexes is strongly correlated to the chirality of the ligand. However, the stereochemical induction of either the ?- or the ?-configuration at the metal ion is also modulated by environmental factors that change the conformational distribution of ligand rotamers. Calculation of the potential energy surface of bis{(R)-N-(1-(4-X-phenyl)ethyl)salicylaldiminato-?(2)N,O}copper(II) with X = Cl at the density functional theory level showed a clear dependence of the helicity-determining angle ? between the two coordination planes on the relative population of different ligand conformers. The influence of different substituents (X = H, Cl, Br, and OCH3) on complex helicity was studied by determination of the absolute configuration at the metal ion in complexes with either (R)- or (S)-configured ligands. X-ray single-crystal analysis showed that (R)-configured ligands with H, Cl, Br induce ?, while OCH3-substituted (R)-configured ligands induce ? in the solid state. According to vibrational circular dichroism and electronic circular dichroism studies in solution, however, all tested complexes with (R)-ligands exhibited a propensity for ?, with high diastereomeric ratio for X = Cl and X = Br and moderate diastereomeric ratio for X = H and X = OCH3 substituted ligands. Therefore, solvation of copper complexes with X = OCH3 goes along with helicity inversion. This solid-state versus solution study demonstrates that it is not sufficient to determine the chiral-at-metal configuration of a compound by X-ray crystallography alone, because the solution structure can be different. This is particularly important for the use of chiral-at-metal complexes as catalysts in stereoselective synthesis. PMID:25695718

  20. Electron spin resonance investigation of copper(II) complexation by soil fulvic acid

    SciTech Connect

    Senesi, N.; Bocian, D.F.; Sposito, G.

    1985-01-01

    Electron Spin Resonance (ESR) spectra are reported and interpreted for Cu(II)-fulvic acid complexes. The data indicated the formation of anisotropic Cu(II) complexes, the metal cation being immobilized in inner-sphere coordination with ligands arranged in a distorted octahedral environment. For the lowest Cu/FA ratio (0.02), calculated ESR parameters suggested the existence of three different coordinating environments for copper ions. When the Cu/FA ratio was increased beyond 0.2, only a dipolar-broadened ESR absorption produced by a large excess of CuS aquo-ions was observable. A highly structured pattern in the g perpendicular to region exhibited by the ESR spectrum at the highest Cu/FA ratio was attributed to superhyperfine coupling of the CuS unpaired electron to N-ligand nuclei. The implied rearrangements of ligands in the complexes after the removal of water emphasize the importance of soil relative humidity to the Cu(II) complexation mechanisms of fulvic acid.

  1. 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.

  2. Spectroscopic study of molecular structures of novel Schiff base derived from o-phthaldehyde and 2-aminophenol and its coordination compounds together with their biological activity

    NASA Astrophysics Data System (ADS)

    Abdallah, Sayed M.; Mohamed, Gehad G.; Zayed, M. A.; El-Ela, Mohsen S. Abou

    2009-09-01

    New Schiff base (H 2L) ligand is prepared via condensation of o-phthaldehyde and 2-aminophenol. The metal complexes of Cr(III), Mn(II), Fe(II), Fe(III), Co(II), Ni(II), Cu(II) and Zn(II) with the ligand are prepared in good yield from the reaction of the ligand with the corresponding metal salts. They are characterized based on elemental analyses, IR, solid reflectance, magnetic moment, electron spin resonance (ESR), molar conductance, 1H NMR and thermal analysis (TGA). From the elemental analyses data, the complexes are proposed to have the general formulae [M(L)(H 2O) n]· yH 2O (where M = Mn(II) ( n = 0, y = 1), Fe(II) ( n = y = 0), Co(II) ( n = 2, y = 0), Ni(II) ( n = y = 2), Cu(II) ( n = 0, y = 2) and Zn(II) ( n = y = 0), and [MCl(L)(H 2O)]· yH 2O (where M = Cr(III) and Fe(III), y = 1-2). The molar conductance data reveal that all the metal chelates are non-electrolytes. IR spectra show that H 2L is coordinated to the metal ions in a bi-negatively tetradentate manner with ONNO donor sites of the azomethine N and deprotonated phenolic-OH. This is supported by the 1H NMR and ESR data. From the magnetic and solid reflectance spectra, it is found that the geometrical structures of these complexes are octahedral (Cr(III), Fe(III), Co(II) and Ni(II) complexes), tetrahedral (Mn(II), Fe(II) and Zn(II) complexes) and square planar (Cu(II) complex). The thermal behaviour of these chelates is studied and the activation thermodynamic parameters, such as, E*, ? H*, ? S* and ? G* are calculated from the DrTGA curves using Coats-Redfern method. The parent Schiff base and its eight metal complexes are assayed against two fungal and two bacterial species. With respect to antifungal activity, the parent Schiff base and four metal complexes inhibited the growth of the tested fungi at different rates. Ni(II) complex is the most inhibitory metal complex, followed by Cr(III) complex, parent Schiff base then Co(II) complex. With regard to bacteria, only two of the tested metal complexes (Mn(II) and Fe(II)) weakly inhibit the growth of the two tested bacteria.

  3. Polymeric Schiff bases as low-voltage redox centers for sodium-ion batteries.

    PubMed

    Castillo-Martínez, Elizabeth; Carretero-González, Javier; Armand, Michel

    2014-05-19

    The redox entity comprising two Schiff base groups attached to a phenyl ring (-N=CH-Ar-HC=N-) is reported to be active for sodium-ion storage (Ar=aromatic group). Electroactive polymeric Schiff bases were produced by reaction between non-conjugated aliphatic or conjugated aromatic diamine block with terephthalaldehyde unit. Crystalline polymeric Schiff bases are able to electrochemically store more than one sodium atom per azomethine group at potentials between 0 and 1.5?V versus Na(+)/Na. The redox potential can be tuned through conjugation of the polymeric chain and by electron injection from donor substituents in the aromatic rings. Reversible capacities of up to 350?mA?h?g(-1) are achieved when the carbon mixture is optimized with Ketjen Black. Interestingly, the "reverse" configuration (-CH=N-Ar-N=HC-) is not electrochemically active, though isoelectronic. PMID:24757125

  4. ``Test kit'' for detection of biologically important anions: A salicylidene-hydrazine based Schiff base

    NASA Astrophysics Data System (ADS)

    Dalapati, Sasanka; Alam, Md Akhtarul; Jana, Sankar; Karmakar, Saswati; Guchhait, Nikhil

    2013-02-01

    Test paper coated with Schiff base [(N,N/-bis(5-nitro-salicylidene)hydrazine] receptor 1 (host) can selectively detect fluoride and acetate ions (guest) by developing yellow color which can be detected by naked-eye both in aqueous-acetonitrile solution and in solid supported test kit. UV-vis spectral analysis shows that the absorption peaks at 288 and 345 nm of receptor 1 gradually decrease its initial intensity and new red shifted absorption bands at 397 nm and 455 nm gradually appear upon addition of increasing amount of F- and AcO- ions over several tested anions such as HPO4-, Cl, Br, I, NO3-, NO2-, HSO4-, HSO3-, and ClO4- in aqueous-acetonitrile solvent. The colorimetric test results and UV-vis spectral analysis are in well agreement with 1H NMR titration results in d6-DMSO solvent. The receptor 1 forms 1:2 stable complexes with F- and AcO- ions. However, similar kind of observation obtained from UV-vis titrations in presence of AcOH corresponds to 1:1 complexation ratio indicating the formation of H-bonding interaction between the receptor and anions (F- and AcO- ions). So, the observed 1:2 complexation ratio can only be explained on the basis of deprotonation (˜1 eqv.) and H-bonding (˜1 eqv.) interactions [1]. The ratiometric analysis of host-guest complexes corroborates well with the proposed theoretical model optimization at Density Functional Theory (DFT) level.

  5. New copper(II) complexes with dopamine hydrochloride and vanillymandelic acid: Spectroscopic and thermal characterization

    NASA Astrophysics Data System (ADS)

    Mohamed, Gehad G.; Nour El-Dien, F. A.; El-Nahas, R. G.

    2011-10-01

    The dopamine derivatives participate in the regulation of wide variety of physiological functions in the human body and in medication life. Increase and/or decrease in the concentration of dopamine in human body reflect an indication for diseases such as Schizophrenia and/or Parkinson diseases. The Cu(II) chelates with coupled products of dopamine hydrochloride (DO.HCl) and vanillymandelic acid (VMA) with 4-aminoantipyrine (4-AAP) are prepared and characterized. Different physico-chemical techniques namely IR, magnetic and UV-vis spectra are used to investigate the structure of these chelates. Cu(II) forms 1:1 (Cu:DO) and 1:2 (Cu:VMA) chelates. DO behave as a uninegative tridentate ligand in binding to the Cu(II) ion while VMA behaves as a uninegative bidentate ligand. IR spectra show that the DO is coordinated to the Cu(II) ion in a tridentate manner with ONO donor sites of the phenolic- OH, -NH and carbonyl- O, while VMA is coordinated with OO donor sites of the phenolic- OH and -NH. Magnetic moment measurements reveal the presence of Cu(II) chelates in octahedral and square planar geometries with DO and VMA, respectively. The thermal decomposition of Cu(II) complexes is studied using thermogravimetric (TG) and differential thermal analysis (DTA) techniques. The activation thermodynamic parameters, such as, energy of activation, enthalpy, entropy and free energy change of the complexes are evaluated and the relative thermal stability of the complexes are discussed.

  6. Mono- and binuclear copper(II) complexes of new hydrazone ligands derived from 4,6-diacetylresorcinol: Synthesis, spectral studies and antimicrobial activity.

    PubMed

    Shebl, Magdy; El-ghamry, Mosad A; Khalil, Saied M E; Kishk, Mona A A

    2014-05-21

    Two new hydrazone ligands, H2L(1) and H2L(2), 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, (1)H NMR, electronic and mass spectra. Reactions of the ligands with several copper(II) salts, including AcO(-), NO3(-), SO4(2-), 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 H2L(1) ligand acts as a neutral or monobasic tridentate ligand while the H2L(2) ligand acts as a bis(monobasic tridentate) ligand. The coordination sites with the copper(II) ion are phenolic oxygen, azomethine nitrogen and triazinic nitrogen (H2L(1) ligand) or isatinic oxygen (H2L(2) 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. PMID:24607473

  7. A study of copper(II) carboxylato complexes with the biological ligands nicotinamide and papaverine

    NASA Astrophysics Data System (ADS)

    Williams, Christina J.; Morris, Harry; Svorec, Jozef; Valková, Miroslava; Valko, Marian; Moncol, Jan; Mazur, Milan; Valach, Fedor; Melnik, Milan

    2003-10-01

    The X-band Electron Spin Resonance spectra, ESR, of Cu(II) complexes with the carboxylic acids, HCOOH, CH 3COOH, ClCH 2COOH, Cl 2CHCOOH, Cl 3CCOOH, F 2ClCOOH, CH 3CH 2COOH, niflumic acid and the ligands nicotinamide and papaverine have been studied. The compounds form either mononuclear or binuclear structures which can be qualitatively correlated with the strengths of the acid and base. Analysis of the spin Hamiltonian parameters for the monomeric species indicate that the molecule has nearly axial symmetry ( g?> g?) with the unpaired electron in the d x2- y2 orbital. In many cases the perpendicular feature is sufficiently well resolved showing superhyperfine features due to the nitrogen ligand nuclei. A? varies over the range 130?188 G and the variation appears to arise as a consequence of changes in g?. The dimeric species show ESR spectra typical of Cu(II)-carboxylate complexes which consist of 3 (4 if E?0) lines. These are assigned to Bz1 , Bx2, y2 and Bz2 since the Q-band spectra of similar molecules indicate that the Bx1, y1 transition(s) lies below Bz2 which is itself near zero field. The observed seven-line hyperfine coupling on the Bz1 transition of some of the dimeric complexes is due to the two equivalent copper nuclei ( I= I1+ I2=3). The singlet-triplet separation has been estimated from the spin Hamiltonian parameters to give values of |2 J| in the range of approximately 220-290 cm -1 which are typical of the compounds of this type.

  8. An investigation of chloride-substituted Schiff bases as corrosion inhibitors for steel

    Microsoft Academic Search

    Kaan C. Emregül; Raif Kurtaran; Orhan Atakol

    2003-01-01

    Polarization and impedance measurements were performed on steel in deaerated 5% HCl solution with and without Schiff base additives within the concentration range 1×10?4–5×10?3 mol\\/dm3. The Schiff base compounds used were salicylaldimine, R, N-(2-chlorophenyl)salicyaldimine, 2Cl-R, N-(3-chlorophenyl)salicyaldimine, 3Cl-R, and N-(4-chlorophenyl)salicyaldimine, 4Cl-R. It was found that when the concentration of the inhibitors were increased the inhibitor efficiencies, ?, also increased with increasing

  9. 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.

  10. A Schiff base derivative for effective treatment of diethylnitrosamine-induced liver cancer in vivo.

    PubMed

    Demirci, Selami; Do?an, Ay?egül; Ba?ak, Ne?e; Telci, Dilek; Dede, Bülent; Orhan, Cemal; Tuzcu, Mehmet; ?ahin, Kazm; ?ahin, Nurhan; Özercan, ?brahim Hanifi; ?ahin, Fikrettin

    2015-06-01

    Hepatocellular carcinoma is one of the most prevalent cancers, with a high morbidity rate, even in developed countries. In the present study, the curative effect of the Schiff base (SB) heterodinuclear copper(II)Mn(II) complex on diethylnitrosamine (DEN)-induced liver carcinoma was investigated. Hepatocarcinoma was initiated by an injection of DEN and promoted by phenobarbital (0.05%) in the diet. In addition, the potential nephrotoxicity of SB was evaluated in a cisplatin-induced nephrotoxicity model. Rats were administered the SB complex (1 and 2 mg/kg body weight/day) for 24 weeks, and cancer progression was investigated by macroscopic, histopathological, and western blot examinations. The administration of SB decreased the incidence and the number of hepatic nodules in a dose-dependent manner by regulating inflammation response and the apoptotic pathway. Western blot analyses from the livers of rats treated with SB after DEN induction showed significantly enhanced Bax and caspase-3 levels, with a marked decrease in the levels of Bcl-2, NF-?B p65 and cyclooxygenase (COX)-2. Results from the nephrotoxicity study showed that, whereas cisplatin increased serum urea nitrogen and creatinine levels, no increase in serum biochemical parameters was detected in SB-treated animals. Moreover, protein levels of NF-E2-related factor-2 (Nrf2) and heme oxygenase-1 were lower, whereas nuclear factor-?B (NF-?B p65) and activator protein-1 levels were higher in the kidneys of cisplatin-treated animals compared with that of the SB groups. Therefore, the SB complex could be an alternative chemotherapeutic option for liver cancer treatment once its safety in clinical applications has been examined. PMID:25714251

  11. Synthesis, structure and luminescence behaviour of bis(tridentate) Schiff base bridged dinuclear lead(II) pseudohalides

    NASA Astrophysics Data System (ADS)

    Chattopadhyay, Soumi; Bhar, Kishalay; Khan, Sumitava; Mitra, Partha; Butcher, Raymond J.; Ghosh, Barindra K.

    2010-03-01

    Two pentacoordinated dinuclear lead(II) compounds [Pb 2(pbap)(N 3) 4] ( 1) and [Pb 2(pbap)(NCS) 4] ( 2) [pbap = N-((1-pyridin-2-yl)benzylidene)- N'-[2-(4-{2-[((1-pyridin-2-yl)benylidene)amino]ethyl}piperazin-1-yl)ethyl]amine] are prepared and characterized using microanalytical, spectroscopic, thermal and other physicochemical results. Single crystal X-ray diffraction measurements have been made to define the metal coordination spheres. Structural analyses reveal dinucleating bis(tridentate) behaviour of the hexadentate Schiff base (pbap) binding two metal ions. In the centrosymmetric dimers 1 and 2, each lead(II) center adopts a distorted square pyramidal geometry with PbN 5 chromophore ligated by each (N p, N i, N a) donor set of pbap and two N atoms of terminal pseudohalides. In DMF solutions at room temperature the complexes display high-energy intraligand 1(?-??) fluorescence.

  12. Biomimetic sensor for certain phenols employing a copper(II) complex.

    PubMed

    Mobin, Shaikh M; Sanghavi, Bankim J; Srivastava, Ashwini K; Mathur, Pradeep; Lahiri, Goutam K

    2010-07-15

    A new dimeric Cu(II) complex [Cu(mu(2)-hep)(hep-H)](2).2PF(6) (1) containing a bidentate (hep-H = 2-(2-hydroxyethyl)pyridine) ligand was synthesized and characterized by single crystal X-ray diffraction studies. Each Cu ion in 1 is in a distorted square pyramidal geometry. Further 1 is used as a modifier in the construction of a biomimetic sensor for determining phenols [phenol (Phe), resorcinol (Res), hydroquinone (HQ), and catechol (Cat)] in phosphate buffer by using cyclic voltammetry (CV), chronocoulometry, electrochemical impedance spectroscopy (EIS), differential pulse voltammetry (DPV), and square wave voltammetry (SWV). DPV has been proposed for trace determination of Phe and Res while SWV for HQ and Cat. The method has been applied for the selective and precise analysis of Phe in commercial injections, Res in hair coloring agents, HQ in photographic developers and cosmetics, and Cat in tea samples and guarana tablets. The calibration curves showed a linear response ranging between 10(-6) and 10(-8) M for all four of the analytes with detection limits (3sigma) of 1.04 x 10(-8), 2.31 x 10(-8), 1.54 x 10(-8), and 0.86 x 10(-8) M for Phe, Res, HQ, and Cat, respectively. The lifetime of the biomimetic sensor was 200 days at room temperature (at least 750 determinations). The catalytic properties of 1-CPE were characterized by chronoamperometry and were found to be in good agreement with Michaelis-Menten kinetics. PMID:20568721

  13. Dimeric samarium(III) alkoxides bearing N 2O 2 tetradentate Schiff bases and their utility for the catalytic epoxidation of trans-chalcone

    Microsoft Academic Search

    Steven A. Schuetz; Elizabeth A. Bowman; Carter M. Silvernail; Victor W. Day; John A. Belot

    2005-01-01

    Two anhydrous, dimeric samarium(III) complexes bearing a bulky ?-alkoxide (diphenylmethoxide) ligand and different “saturated” tetradentate Schiff bases {bis-5,5?-(1,3-propanediyldiimino)-2,2-dimethyl-4-hexene-3-onato and bis-5,5?-(2,2-dimethyl-1,3-propanediyldiimino)-2,2-dimethyl-4-hexene-3-onato} were synthesized and fully characterized. The complexes differ only in alkyl substitution at the three-carbon amino linker between the ketoiminato halves, with one having a CH2 group and the other a C(CH3)2 substituent along the free-ligand idealized mirror plane. Both

  14. Rapid Photodynamics of Vitamin B6 Coenzyme Pyridoxal 5-Phosphate and Its Schiff Bases in Solution

    E-print Network

    Toney, Michael

    Rapid Photodynamics of Vitamin B6 Coenzyme Pyridoxal 5-Phosphate and Its Schiff Bases in Solution, 2007; In Final Form: February 4, 2008 The active form of vitamin B6, pyridoxal 5-phosphate (PLP (absorbing at 410 nm) tautomers in solution. 1. Introduction Pyridoxal 5-phosphate (PLP), one form of vitamin

  15. Structural, Electrochemical, and Spectroscopic Investigation of Acetate Bridged Dinuclear Tetrakis-Schiff Base Macrocycles of Mn

    E-print Network

    Dinolfo, Peter H.

    -Schiff Base Macrocycles of Mn and Zn Subhadeep Kal, Alexander S. Filatov, and Peter H. Dinolfo*, Department York 12222, United States *S Supporting Information ABSTRACT: The synthesis of Mn2LAc+ , Zn2LAc,6-diformylphenol and 2,2-diamino-N-meth- yldiethylamine resulting in an N6O2 coordination environment. In Mn2LAc

  16. QSAR study using topological indices for inhibition of carbonic anhydrase II by sulfanilamides and Schiff bases

    Microsoft Academic Search

    Alexandru T. Balaban; Subhash C. Basak; Adrian Beteringhe; Denise Mills; Claudiu T. Supuran

    2004-01-01

    A QSAR study of two sets of carbonic anhydrase inhibitors is presented using a variety of molecular descriptors including topological indices. The first set consists of 29 benzenesulphonamides, and the second set includes 35 sulphanilamide Schiff bases. Two regression methodologies have been used involving ridge regression and the CODESSA program, and their results are compared with those of previous QSAR

  17. Schiff bases as corrosion inhibitors for aluminium in hydrochloric acid solution

    Microsoft Academic Search

    Gamal K. Gomma; Mostafa H. Wahdan

    1995-01-01

    The inhibition of the corrosion of Al in hydrochloric acid solution by some Schiff bases has been studied in relation to the concentration of the inhibitor as well as the temperature. The inhibition efficiency increases with increasing inhibitor concentration. The inhibitors appear to function through the Langmuir isotherm. Polarisation studies indicate that the compounds used are cathodic inhibitors. The corrosion

  18. Synthesis and biological evaluations of some Schiff-base esters of ferrocenyl aniline and simple aniline

    Microsoft Academic Search

    Haq Nawaz; Zareen Akhter; Sumaira Yameen; Huamaira M. Siddiqi; Bushra Mirza; Arshia Rifat

    2009-01-01

    The synthesis and biological studies of some long chain esters containing Schiff bases and their ferrocenyl analogues were carried out. The 4-amino ferrocene was prepared by the reported method. Long chain esters were synthesized by the condensation of different aliphatic acids with the corresponding aldehyde. The esters were then reacted with aniline as well as with 4-aminophenyl ferrocene to give

  19. Effect of Schiff's Bases as Corrosion Inhibitors on Mild Steel in Sulphuric Acid

    Microsoft Academic Search

    R. K. UPADHYAY; S. P. MATHUR

    Mass loss and thermometric methods have been used to study the corrosion inhibitory effect of synthesised Schiff's bases viz . N-(furfurilidine) - 4- methoxy aniline (SB 1), N-(furfurilidine) - 4- methylaniline (SB 2), N- (salicylidine) - 4- methoxy aniline (SB 3), N-(cinnamalidine) - 4 -methoxy aniline (SB 4) and N-(cinnamalidine) - 2-methylaniline (SB 5) on mild steel in sulphuric acid

  20. Physicochemical characterization of novel Schiff bases derived from developed bacterial cellulose 2,3-dialdehyde.

    PubMed

    Keshk, Sherif M A S; Ramadan, Ahmed M; Bondock, Samir

    2015-08-20

    The synthesis of two novel Schiff's bases (cellulose-2,3-bis-[(4-methylene-amino)-benzene-sulfonamide] (5) & cellulose-2,3-bis-[(4-methylene-amino)-N-(thiazol-2-yl)-benzenesulfonamide] (6) via condensation reactions of periodate oxidized developed bacterial cellulose ODBC (2) with sulfa drugs [sulfanilamide (3) & sulfathiazole (4)] was reported. The physicochemical characterization of the condensation products was performed using FTIR, (1)H NMR, (13)C NMR spectral analyses, X-ray diffraction and DTA. The ODBC exhibited the highest degree of oxidation based on the aldehyde group number percentage (82.9%), which confirms the highest reactivity of developed bacterial cellulose [DBC (1)]. The X-ray diffractograms indicated an increase in the interplanar distance of the cellulose Schiff base (6) compared to ODBC (2) due to sulfathiazole (4) inclusion between ODBC (2) sheets corresponding to the 11¯0 plane. In addition, the aldehyde content of Schiff base (6) was (20.8%) much lower than that of Schiff base (5) (41.5%). These results confirmed the high affinity of sulfathiazole (4) to the ODBC (2) chain, and the substantial changes in the original properties of ODBC were due to these chemical modifications rather than the sulfanilamide (3). PMID:25965481

  1. 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*, ?H*, ?S* and ?G* 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 ?H*, and ?G* values suggested endothermic character for the thermal decomposition steps.

  2. Some new nano-structure zinc(II) coordination compounds of an imidazolidine Schiff base: spectral, thermal, antimicrobial properties and DNA interaction.

    PubMed

    Montazerozohori, Morteza; Musavi, Sayed Alireza; Naghiha, Asghar; Zohour, Mostafa Montazer

    2014-08-14

    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, (1)H and (13)C NMR and UV-Visible spectroscopy. The resulting data from spectral investigation especially (1)H and (13)C 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 21.80-78.10nm 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(*), ?H(*), ?S(*) and ?G(*) 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 ?H(*), and ?G(*) values suggested endothermic character for the thermal decomposition steps. PMID:24747864

  3. Mixed ligand copper(ii) dicarboxylate complexes: the role of co-ligand hydrophobicity in DNA binding, double-strand DNA cleavage, protein binding and cytotoxicity.

    PubMed

    Loganathan, Rangasamy; Ramakrishnan, Sethu; Ganeshpandian, Mani; Bhuvanesh, Nattamai S P; Palaniandavar, Mallayan; Riyasdeen, Anvarbatcha; Akbarsha, Mohamad Abdulkadhar

    2015-05-27

    A few water soluble mixed ligand copper(ii) complexes of the type [Cu(bimda)(diimine)] , where bimda is N-benzyliminodiacetic acid and diimine is 2,2'-bipyridine (bpy, ) or 1,10-phenanthroline (phen, ) or 5,6-dimethyl-1,10-phenanthroline (5,6-dmp, ) or 3,4,7,8-tetramethyl-1,10-phenanthroline (3,4,7,8-tmp, ) and dipyrido[3,2-d: 2',3'-f]quinoxaline (dpq, ), have been successfully isolated and characterized by elemental analysis and other spectral techniques. The coordination geometry around copper(ii) in is described as distorted square based pyramidal while that in is described as square pyramidal. Absorption spectral titrations and competitive DNA binding studies reveal that the intrinsic DNA binding affinity of the complexes depends upon the diimine co-ligand, dpq () > 3,4,7,8-tmp () > 5,6-dmp () > phen () > bpy (). The phen and dpq co-ligands are involved in the ?-stacking interaction with DNA base pairs while the 3,4,7,8-tmp/5,6-dmp and bpy co-ligands are involved in respectively hydrophobic and surface mode of binding with DNA. The small enhancement in the relative viscosity of DNA upon binding to supports the DNA binding modes proposed. Interestingly, and are selective in exhibiting a positive induced CD band (ICD) upon binding to DNA suggesting that they induce B to A conformational change. In contrast, and show CD responses which reveal their involvement in strong DNA binding. The complexes are unique in displaying prominent double-strand DNA cleavage while effects only single-strand DNA cleavage, and their ability to cleave DNA in the absence of an activator varies as > > > > . Also, all the complexes exhibit oxidative double-strand DNA cleavage activity in the presence of ascorbic acid, which varies as > > > > . The ability of the complexes to bind and cleave the protein BSA varies in the order > > > > . Interestingly, and cleave the protein non-specifically in the presence of H2O2 as an activator suggesting that they can act also as chemical proteases. It is remarkable that exhibit cytotoxicity against human breast cancer cell lines (MCF-7) with potency higher than the widely used drug cisplatin indicating that they have the potential to act as effective anticancer drugs in a time dependent manner. The morphological assessment data obtained by using Hoechst 33258 staining reveal that and induce apoptosis much more effectively than other complexes. Also, the alkaline single-cell gel electrophoresis study (comet assay) suggests that the same complexes induce DNA fragmentation more efficiently than others. PMID:25954774

  4. Copper(II) diamino acid complexes: quantum chemical computations regarding diastereomeric effects on the energy of complexation.

    PubMed

    Zuilhof, Han; Morokuma, Keiji

    2003-08-21

    [reaction: see text] Quantum chemical calculations were used to rationalize the observed enantiodifferentiation in the complexation of alpha-amino acids to chiral Cu(II) complexes. Apart from Cu(II)[bond]pi interactions and steric repulsions between the anchoring cholesteryl-Glu moiety and an aromatic amino acid R group, hydrogen bonding also plays a role. In fact, in the case of tryptophan, C[double bond]O...H[bond]N hydrogen bonding between the glutamate moiety and the tryptophan N[bond]H group compensates for the loss of intramolecular hydrogen-bonding and diminished Cu(II)[bond]pi interactions. PMID:12916986

  5. Modeling of the various minima on the potential energy surface of bispidine copper(II) complexes: a further test for ligand field molecular mechanics.

    PubMed

    Bentz, Alexander; Comba, Peter; Deeth, Robert J; Kerscher, Marion; Seibold, Björn; Wadepohl, Hubert

    2008-10-20

    Copper(II) complexes of bispidines (bispidine = tetra-, penta-, or hexadentate ligand, based on the 3,7-diazabicyclo[3.3.1]nonane backbone) display several isomeric forms. Depending on the substitution pattern of the bispidine and the type of coligands used, the structure elongates along one of the three potential Jahn-Teller axes. In an effort to develop a computational tool which can predict which isomer is observed, 23 bispidine-copper(II) complexes with 19 different ligands are analyzed theoretically by ligand field molecular mechanics (LFMM). With two exceptions, the lowest-energy LFMM structure and the experimental solid-state structure agree concerning the Jahn-Teller axis. However, in most cases and especially for six-coordinate complexes, LFMM predicts a second local minimum within a few kilojoules per mole. Although detailed analysis reveals that the current force field is too "stiff", reasonable quantitative reproduction of the structural data is achieved with Cu-L bond length root mean square (rms) deviations for nine complexes of 0.05 A or less and with 20 reproduced to a rms deviation of 0.1 A or less. Across all of the complexes, the Cu-amine and Cu-pyridyl bond length rms deviations are 0.07 and 0.12 A, respectively. PMID:18811152

  6. Synthesis, crystal structures and magnetic properties of bis(?-dialkoxo)-bridged linear trinuclear copper(II) complexes with aminoalcohol ligands: a theoretical/experimental magneto-structural study.

    PubMed

    Seppälä, Petri; Colacio, Enrique; Mota, Antonio J; Sillanpää, Reijo

    2012-03-01

    The bis(?-dialkoxo)-bridged trinuclear copper(II) complexes [Cu(3)(ap)(4)(ClO(4))(2)EtOH] (1), [Cu(3)(ap)(4)(NO(3))(2)] (2), [Cu(3)(ap)(4)Br(2)] (3) and [Cu(3)(ae)(4)(NO(3))(2)] (4) (ae = 2-aminoethanolato and ap = 3-aminopropanolato) have been synthesised via self-assembly from chelating aminoalcohol ligands with the corresponding copper(II) salts. The complexes are characterised by single-crystal X-ray diffraction analyses and variable temperature magnetic measurements. The crystal structures of complexes 1-4 consist of slightly bent linear or linear trinuclear [Cu(3)(aa)(4)](2+) (aa = aminoalcoholato) units to which the perchlorate, nitrate or bromide anions are weakly coordinated. The adjacent trinuclear units of 1-4 are connected together by hydrogen bonds and bridging nitrate or bromide anions resulting in the formation of 2D layers. Magnetic studies of 1, 2 and 4 show that J values vary from -379 to +36.0 cm(-1) as the Cu-O-Cu angle (?) and the out-of-plane shift of the carbon atom of the bridging alkoxo group (?) vary from 103.7 to 94.4° and from 0.9 to 35.5°, respectively. Magnetic exchange coupling constants calculated by DFT methods are of the same nature and magnitude as the experimental ones. For complexes 1, 2 and 4, which have complementarity effects between the ? and ? angles (small ? values are associated with large ? values and vice versa), an almost linear relationship between the calculated J values with ? angles could be established, thus supporting that the ? and ? angles are the two key structural factors that determine the magnetic exchange coupling for such a type of compounds. Complex 3 does not obey this linear correlation because of the existence of counter-complementarity effects between these angles (small ? values are associated with small ? values and vice versa). It is of interest that the theoretical calculations for the magnetic exchange interaction between next-nearest neighbours indicate that the usual approximation in experimental studies of neglecting the magnetic coupling between the next-nearest neighbours in linear trinuclear complexes could lead to considerable errors, especially when J(1) and J(2) are of the same order of magnitude as J(3). PMID:22234645

  7. In vitro cytotoxic activities, DNA-, and BSA-binding studies of a new dinuclear copper(II) complex with N-[3-(dimethylamino)propyl]-N'-(2-carboxylatophenyl)-oxamide as ligand.

    PubMed

    Jiao, Jing; Jiang, Man; Li, Yan-Tuan; Wu, Zhi-Yong; Yan, Cui-Wei

    2014-02-01

    A new dinuclear copper(II) complex bridged by N-[3-(dimethylamino)propyl]-N'- (2-carbo-xylatophenyl)oxamide (H3 dmapob), and endcapped with 2,2'-diamino-4,4'-bithiazole (dabt), namely [Cu?(dmapob)(dabt)(CH?OH)(pic)]·(DMF)?.?? ·(CH?OH)?.?? has been synthesized and characterized by elemental analysis, molar conductivity measurement, infrared and electronic spectra studies, and single-crystal X-ray diffraction. In the crystal structure, both copper(II) ions have square-pyramidal coordination geometries. The Cu···Cu separation through the oxamido bridge is 5.176(9) Å. A two-dimensional supramolecular framework is formed through hydrogen bonds and ?-? stacking interactions. The reactivities toward herring sperm DNA and bovine serum albumin (BSA) show that the complex can interact with the DNA via intercalation mode and bind to the BSA responsible for quenching of tryptophan fluorescence by the static quenching mechanism. The in vitro anticancer activities suggest that the copper(II) complex is active against the selected tumor cell lines. The influence of different bridging ligands in dinuclear complexes on the DNA- and BSA-binding properties as well as anticancer activities is preliminarily discussed. PMID:24497175

  8. 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

  9. SYNTHESIS AND STRUCTURAL FEATURES OF COPPER(II) COMPLEXES OF BENZOIC ACID AND METHYL SUBSTITUTED BENZOIC ACID HYDRAZIDES AND X-RAY STRUCTURE OF Cu[C6H5CONHNH2]2(NO3)2

    Microsoft Academic Search

    Olusegun A. Odunola; Idowu O. Adeoye; Joseph A. O. Woods

    2002-01-01

    The synthesis, spectroscopic, magnetic and biological activities of copper(II) complexes of benzoic acid hydrazides (BAH) and o, m, and p-substituted methylbenzoic acid hydrazides (MBAH) and the single crystal X-ray structure for bis(benzoic acid hydrazide)copper(II) nitrate {Cu[BAH]2-(NO3)2} (BAH=Benzoic acid hydrazide) are reported. The composition of the ligands was established by elemental analyses, H NMR, and GC-MS. Magnetic susceptibility, electronic and infrared

  10. Synthesis, characterization, antioxidative activity and DNA binding properties of the copper(II), zinc(II), nickel(II) complexes with 1,2-Di(4'-iminonaringenin)ethane.

    PubMed

    Li, Yong; Yang, Zheng-Yin; Li, Tian-Rong

    2008-11-01

    A novel naringenin Schiff base ligand (1,2-di(4'-iminonaringenin)ethane, H6L) and its three transition metal complexes [Cu(II) complex (1), Zn(II) complex (2), and Ni(II) complex (3)] have been prepared and characterized on the basis of elemental analysis, molar conductivity, 1H-NMR, mass spectra, UV-vis spectra, and IR spectra. The DNA-binding properties of the ligand and its complexes have been investigated by absorption spectroscopy, fluorescence spectroscopy, ethidium bromide (EB) displacement experiments, and viscosity measurement. The results indicated that the ligand and its complexes can bind to DNA. The binding affinity of the Cu(II) complex (1) is higher than that of the ligand and the other two complexes. The intrinsic binding constant (Kb) of the complex (1) is 3.3x10(6). In addition, the suppression ratio for O2-. and HO. was determined. The 50% inhibition obtained for the ligand and its three complexes demonstrates that, compared to the ligand, the complexes exhibit higher antioxidative activity in the suppression of O2-. and HO.. PMID:18981601

  11. C-H activation in pyridoxal-5'-phosphate and pyridoxamine-5'-phosphate Schiff bases: effect of metal chelation. A computational study.

    PubMed

    Casasnovas, Rodrigo; Frau, Juan; Ortega-Castro, Joaquin; Donoso, Josefa; Muñoz, Francisco

    2013-02-28

    This study reports the carbon acidities of C? and C4? atoms in the Schiff bases of pyridoxal-5?-phosphate (PLP) and pyridoxamine-5?-phosphate (PMP) complexed with several biologically available metal ions (Mg2+, Ni2+, Zn2+, Cu2+, Al3+, and Fe3+). Density functional theory calculations were carried out to determine the free energies of proton exchange reactions of a set of 18 carbon acids and a Schiff base used as a reference species. The experimental pK(a) values of such carbon acids were used to calibrate the computed free energies in a range of 30 pK(a) units. Eventually, the pK(a)s of the chelates were obtained by calculating the corresponding free energies against the same reference species and by considering the previous calibration. The carbon acidity of C? in the chelates of Mg2+, Ni2+, Zn2+, and Cu2+ varies between pK(a) 22 and pK(a) 13 whereas the pK(a) values of C4? range between 18 and 7. Chelation of trivalent metals Al3+ and Fe3+ causes further decrease of the pK(a) values of C? and C4? down to 10 and 5, respectively. The results highlight the efficiency of the combined action of Schiff base formation and metal chelation to activate the C? carbon of amino acids (pK(a) 29 for zwitterionic alanine). Our results explain that the experimental increase of transamination rates by Zn2+ chelation is due to stabilization of the reactive Schiff base species with respect to the free ligand under physiological pH conditions. However, the increase in reactivity for transamination due to Cu2+ and Al3+ chelation is mostly due to C–H ligand activation. Each metal ion activates the C? and C4? carbon atoms to a different extent, which can be exploited to favor specific reactions on the amino acids in aqueous solution. Metal chelation hinders both intramolecular and intermolecular proton-transfer reactions of the imino, phenol, and carboxylate groups. This is the only apparent inconvenience of metal complexes in enzymatic reactions, which, in turn, proposes their consideration for enzyme inhibition. PMID:23387946

  12. 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)

    ?nci, Duygu; Ayd?n, Rahmiye; Vatan, Özgür; Y?lmaz, Dilek; Gençkal, Hasene Mutlu; Zorlu, Yunus; Cava?, 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.

  13. Synthesis, spectroscopic characterization and pH dependent photometric and electrochemical fate of Schiff bases.

    PubMed

    Rauf, Abdur; Shah, Afzal; Abbas, Saghir; Rana, Usman Ali; Khan, Salah Ud-Din; Ali, Saqib; Zia-Ur-Rehman; Qureshi, Rumana; Kraatz, Heinz-Bernhard; Belanger-Gariepy, Francine

    2015-03-01

    A new Schiff base, 1-((4-bromophenylimino) methyl) naphthalen-2-ol (BPIMN) was successfully synthesized and characterized by (1)H NMR, (13)C NMR, FTIR and UV-Vis spectroscopy. The results were compared with a structurally related Schiff base, 1-((4-chlorophenylimino) methyl) naphthalen-2-ol (CPIMN). The photometric and electrochemical fate of BPIMN and CPIMN was investigated in a wide pH range. The experimental findings were supported by quantum mechanical approach. The redox mechanistic pathways were proposed on the basis of results obtained electrochemical techniques. Moreover, pH dependent UV-Vis spectroscopy of BPIMN and CPIMN was carried out and the appearance of isosbestic points indicated the existence of these compounds in different tautomeric forms. PMID:25437845

  14. The X-ray absorption spectroscopic model of the copper(II) imidazole complex ion in liquid aqueous solution: a strongly solvated square pyramid.

    PubMed

    Frank, Patrick; Benfatto, Maurizio; Hedman, Britt; Hodgson, Keith O

    2012-02-20

    Cu K-edge extended X-ray absorption fine structure (EXAFS) and Minuit X-ray absorption near-edge structure (MXAN) analyses were combined to evaluate the structure of the copper(II) imidazole complex ion in liquid aqueous solution. Both methods converged to the same square-pyramidal inner coordination sphere [Cu(Im)(4)L(ax)](2+) (L(ax) indeterminate) with four equatorial nitrogen atoms at EXAFS, 2.02 ± 0.01 Å, and MXAN, 1.99 ± 0.03 Å. A short-axial N/O scatterer (L(ax)) was found at 2.12 ± 0.02 Å (EXAFS) or 2.14 ± 0.06 Å (MXAN). A second but very weak axial Cu-N/O interaction was found at 2.9 ± 0.1 Å (EXAFS) or 3.0 ± 0.1 Å (MXAN). In the MXAN fits, only a square-pyramidal structural model successfully reproduced the doubled maximum of the rising K-edge X-ray absorption spectrum, specifically excluding an octahedral model. Both EXAFS and MXAN also found eight outlying oxygen scatterers at 4.2 ± 0.3 Å that contributed significant intensity over the entire spectral energy range. Two prominent rising K-edge shoulders at 8987.1 and 8990.5 eV were found to reflect multiple scattering from the 3.0 Å axial scatterer and the imidazole rings, respectively. In the MXAN fits, the imidazole rings took in-plane rotationally staggered positions about copper. The combined (EXAFS and MXAN) model for the unconstrained cupric imidazole complex ion in liquid aqueous solution is an axially elongated square-pyramidal core, with a weak nonbonded interaction at the second axial coordination position and a solvation shell of eight nearest-neighbor water molecules. This core square-pyramidal motif has persisted through [Cu(H(2)O)(5)](2+), [Cu(NH(3))(4)(NH(3),H(2)O)](2+), (1, 2) and now [Cu(Im)(4)L(ax))](2+) and appears to be the geometry preferred by unconstrained aqueous-phase copper(II) complex ions. PMID:22316238

  15. Schiff-base-functionalized mesoporous silica SBA-15: Covalently bonded assembly of blue nanophosphors

    NASA Astrophysics Data System (ADS)

    Li, Ying; Yan, Bing

    2009-05-01

    Two kinds of Schiff-base-functionalized organic-inorganic mesoporous luminescent hybrid materials have been obtained by co-condensation of tetraethyl orthosilicate and the organosilane in the presence of Pluronic P123 surfactant as a template. N, N'-Bis(salicylidene)-1,3-propanediamine (BSPA) and N, N', N?-tris(salicylidene)-(2-aminoethyl) amine (TSAEA), possessing two different representative structures, were firstly prepared and then functionalized with trialkoxylsilyl groups through the hydrogen transfer reactions between the active hydroxyl groups of the Schiff-base compounds and the internal ester group of isocyanate in 3-(triethoxysilyl)-propyl isocyanate (TESPIC). Schiff-base grafted to the coupling agent 3-(triethoxysilyl)-propyl isocyanate (TESPIC) was used as the precursor for the preparation of mesoporous materials. The luminescence properties of these resulting materials were characterized in detail, and the results reveal that they all have high surface area, uniformity in the mesostructure. The resulting materials (BSPA-SBA-15 and TSAEA-SBA-15) exhibit regular uniform microstructures and no phase separation happened because the organic and the inorganic compounds were covalently linked through Si-O bonds via a self-assembly process. Furthermore, these two materials have the similar luminescence range in the blue range.

  16. Synthesis, X-ray Structure, Spectroscopic Properties and DFT Studies of a Novel Schiff Base

    PubMed Central

    Chen, Kew-Yu; Tsai, Hsing-Yang

    2014-01-01

    A series of Schiff bases, salicylideneaniline derivatives 1–4, was synthesized under mild conditions and characterized by 1H NMR, HRMS, UV-Vis and fluorescence spectra, and single-crystal X-ray diffraction. In solid and aprotic solvents 1–4 exist mainly as E conformers that possess an intramolecular six-membered-ring hydrogen bond. A weak intramolecular C–H···F hydrogen bond is also observed in fluoro-functionalized Schiff base 4, which generates another S(6) ring motif. The C–H···F hydrogen bond further stabilizes its structure and leads it to form a planar configuration. Compounds 1–3 exhibit solely a long-wavelength proton-transfer tautomer emission, while dipole-functionalized Schiff base 4 shows remarkable dual emission originated from the excited-state intramolecular charge transfer (ESICT) and excited-state intramolecular proton transfer (ESIPT) states. Furthermore, the geometric structures, frontier molecular orbitals (MOs) and the potential energy curves for 1–4 in the ground and the first singlet excited state were fully rationalized by density functional theory (DFT) and time-dependent DFT calculations. PMID:25329613

  17. Synthesis, magnetochemical studies and X-ray molecular structures of some mononuclear copper(II)–1 H-pyrazole adducts and mono(?-pyrazolate) bridged dicopper(II) complexes derived from N-salicylidenearoylhydrazines

    Microsoft Academic Search

    M. F. Iskander; T. E. Khalil; W. Haase; R. Werner; I. Svoboda; H. Fuess

    2001-01-01

    1H-Pyrazole complexes, [Cu(HL)HPz Cl] nH2O and [Cu(L)HPz] nH2O were prepared and characterized, where HL and L, respectively, refer to the mononegative and dinegative N-salicylidenearoylhydrazine anions. The X-ray crystal and molecular structure of [monochloro(N-salicylidenebenzoylhydrazinato)ONO(?1)monopyrazole] copper(II) monohydrate, [Cu(HSBzh)HPz Cl] H2O, and [(N-salicylidenebenzoylhydrazinato)ONO(?2)monopyrazole] copper(II) hemihydrate, [Cu(SBzh)HPz] 1\\/2H2O, were determined. The Cu(II) in [Cu(HSBzh)HPz Cl] H2O is in a distorted square pyramidal environment and

  18. 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 ?M.

  19. Solvent extraction of palladium(II) with a Schiff base and separation of palladium from Pd(II)-Pt(VI) mixture

    SciTech Connect

    Ouyang, J.M.

    1999-09-01

    A new Schiff base extractant, N,N{prime}-bis[1-phenyl-3-methyl-5-hydroxy-pyrazole-4-benzylidenyl]-1,3-propylene diamine (H{sub 2}A) was synthesized and characterized. The extraction mechanism of palladium(II) from HNO{sub 3} or HCIO{sub 2} medium with H{sub 2}A in chloroform or toluene was investigated. The influences of the Schiff base concentration in the organic phase, the concentration of palladium, the pH and anions (Cl{sup {minus}}, SO{sub 4}{sup =}, NO{sub 3}{sup {minus}}, ClO{sub 4}{sup {minus}}) in the aqueous phase and the temperature on the distribution ration for palladium (II) have been examined. The extracted complex has been confirmed by chemical analysis, thermoanalyses and IR spectroscopy. It was found that palladium is extracted according to the following extraction reaction: Pd(H{sub 2}O){sub 2}Cl{sub 2(a)} + H{sub 2}A{sub (o)} == Pd(HA)Cl{sub (o)}+H{sup +}{sub (a)} + Cl{sup {minus}}{sub (a)} + 2H{sub 2}O. The extraction equilibrium constants of palladium(II) were 8.4 and 21.3 in chloroform and toluene diluents, respectively. The values for the enthalpy and standard free energy of extraction were also obtained. The separation of Pd(II) from the mixed solution of Pd(II)-Pt(IV) was achieved by adjusting the pH.

  20. Tuning the gas phase redox properties of copper(II) ternary complexes of terpyridines to control the formation of nucleobase radical cations.

    PubMed

    Lam, Adrian K Y; Abrahams, Brendan F; Grannas, Martin J; McFadyen, W David; O'Hair, Richard A J

    2006-11-14

    Electrospray ionization (ESI) tandem mass spectrometry (MS/MS) of ternary copper(II) complexes of [Cu(terpyX)(M)]2+ (where terpyX = is a substituted 2,2':6',2''-terpyridine ligand; M = the nucleobases: adenine, guanine, thymine and cytosine) was examined as a means of forming radical cations of nucleobases in the gas phase. The following substituents were examined: 4'-NMe2-2,2':6',6''-terpyridine; 4'-OH-2,2':6',6''-terpyridine; 4'-F-2,2':6',6''-terpyridine; 2,2':6',6''-terpyridine; 4'-Cl-2,2':6',6''-terpyridine; 4'-Br-2,2':6',6''-terpyridine; 4'-CO2H-2,2':6',6''-terpyridine; 4'-NO2-2,2':6',6''-terpyridine and 6,6''-dibromo-2',2:6',2''-terpyridine. Each of the ternary complexes [Cu(terpyX)(M)]2+ was mass selected and subjected to collision induced dissociation (CID) in a quadrupole ion trap. The types of fragmentation reactions observed for these complexes depend on the nature of the substituent on the terpyridine ligand, while the yields of the radical cations of the nucleobases follow the order of their ionization energies (IEs): G (lowest IE) > A > C > T (highest IE). In general, radical cation formation is favoured for electron withdrawing substituents (e.g. NO2) while loss of the neutral nucleobase is favoured for electron donating substituents (e.g. NMe2). Loss of the protonated nucleobase is a major fragmentation pathway for the OH substituted terpyridine system, consistent with its ability to bind to a metal centre as a deprotonated ligand. Crystal structure determinations of (6,6''-dibromo-2',2:6',2''-terpyridine)bis(nitrato)copper(II) and diaqua(4'-oxo-2,2':6',6''-terpyridine)copper(II) nitrate monohydrate were performed and correlated with the ESI results. PMID:17060991

  1. Crystal structure characterization as well as theoretical study of spectroscopic properties of novel Schiff bases containing pyrazole group

    NASA Astrophysics Data System (ADS)

    Guo, Jia; Ren, Tiegang; Zhang, Jinglai; Li, Guihui; Li, Weijie; Yang, Lirong

    2012-09-01

    A series of novel Schiff bases containing pyrazole group were synthesized using 1-aryl-3-methyl-4-benzoyl-5-pyrazolone and phenylenediamine as the starting materials. All as-synthesized Schiff bases were characterized by means of NMR, FT-IR, and MS; and the molecular geometries of two Schiff bases as typical examples were determined by means of single crystal X-ray diffraction. In the meantime, the ultraviolet-visible light absorption spectra and fluorescent spectra of various as-synthesized products were also measured. Moreover, the B3LYP/6-1G(d,p) method was used for the optimization of the ground state geometry of the Schiff bases; and the spectroscopic properties of the products were computed and compared with corresponding experimental data based on cc-pVTZ basis set of TD-B3LYP method. It has been found that all as-synthesized Schiff bases show a remarkable absorption peak in a wavelength range of 270-370 nm; and their maximum emission peaks are around 344 nm and 332 nm, respectively.

  2. Synthesis and electrochromic, acidochromic properties of Schiff bases containing triphenylamine and thiophene units.

    PubMed

    Wu, Xiaotong; Wang, Wen; Li, Bin; Hou, Yanjun; Niu, Haijun; Zhang, Yanhong; Wang, Shuhong; Bai, Xuduo

    2015-04-01

    A series of Schiff bases (SBs) were designed and prepared from 2-thiophenecarboxaldehyde and different triphenylamine (TPA) derivatives. The structures of the compounds were characterized by Fourier transform infrared (FT-IR), hydrogen nuclear magnetic resonance (1H NMR). The optical and electrochemical properties were tested by ultraviolet-visible (UV-vis) spectroscopy and cyclic voltammetry (CV) techniques. The SBs exhibited stable and reversible electrochromic properties. Furthermore, multiple reversible colors states were also observed with the change of pH. Consequently, the SBs can be used as electrochromic and acidochromic materials. PMID:25617980

  3. Synthesis and electrochromic, acidochromic properties of Schiff bases containing triphenylamine and thiophene units

    NASA Astrophysics Data System (ADS)

    Wu, Xiaotong; Wang, Wen; Li, Bin; Hou, Yanjun; Niu, Haijun; Zhang, Yanhong; Wang, Shuhong; Bai, Xuduo

    2015-04-01

    A series of Schiff bases (SBs) were designed and prepared from 2-thiophenecarboxaldehyde and different triphenylamine (TPA) derivatives. The structures of the compounds were characterized by Fourier transform infrared (FT-IR), hydrogen nuclear magnetic resonance (1H NMR). The optical and electrochemical properties were tested by ultraviolet-visible (UV-vis) spectroscopy and cyclic voltammetry (CV) techniques. The SBs exhibited stable and reversible electrochromic properties. Furthermore, multiple reversible colors states were also observed with the change of pH. Consequently, the SBs can be used as electrochromic and acidochromic materials.

  4. Copper(ii) cyclam-based complexes for radiopharmaceutical applications: synthesis and structural analysis† †The HTML version of this article has been enhanced with colour images. ‡ ‡Electronic supplementary information (ESI) available: Packing diagrams for the Cu(H2TETA) structures and further details of the compounds used in the structural distortion analysis. See DOI: 10.1039/b615329a Click here for additional data file. Click here for additional data file.

    PubMed Central

    Silversides, Jon D.; Allan, Cheryll C.

    2007-01-01

    Two molecular structures of the copper(ii) complex, Cu(H2TETA), have been determined by X-ray crystallography. The Jahn–Teller distortion differs between the two structures; occurring either along the axis of the pendant acetate arms or across the macrocyclic ring. An analysis of deposited data from over one hundred copper(ii) cyclam X-ray structures in the Cambridge Structural Database (CSD) reveals that Jahn–Teller distortion across the ring is highly unusual for such compounds in the solid state. Novel chelators based on the piperazino/side-bridged cyclam have been prepared and copper(ii) complexes formed. The single crystal X-ray structures of two copper(ii) complexes, with either an ester or acid N-pendant arm, have been determined and in both cases the pendant arm is bound to the metal centre. PMID:17308678

  5. Evolution of copper(II) as a new alkene amination promoter and catalyst

    PubMed Central

    Chemler, Sherry R.

    2010-01-01

    Copper(II) carboxylates and chiral copper(II) triflate·bis(oxazoline) complexes promote and catalyze intramolecular alkene carboamination, diamination and aminooxygenation reactions, creating an array of nitrogen heterocycles. High diastereoselectivity and enantioselectivity can be achieved in these transformations. This account reviews the discovery and development of these useful and interesting reactions. PMID:21379363

  6. An electrochemical procedure coupled with a Schiff base method; application to electroorganic synthesis of new nitrogen-containing heterocycles

    SciTech Connect

    Dowlati, Bahram; Othman, Mohamed Rozali [School of Chemical Sciences and Food Technology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor (Malaysia)

    2013-11-27

    The synthesis of Nitrogen-containing heterocycles has been achieved using chemical and electrochemical methods, respectively. The direct chemical synthesis of nucleophiles proceeds through the Schiff base chemical reaction. This procedure offers an alternate reaction between dicarbonyl compounds and diamines leads to the formation of products. The results indicate that the Schiff base chemical method for synthesis of the product has successfully performed in excellent overall yield. In the electrochemical step, a series of Nitrogen-containing compounds were electrosynthesized. Various parameters such as the applied potential, pH of the electrolytic solution, cell configuration and also purification techniques, were carried out to optimize the yields of corresponding products. New Nitrogen-containing heterocycle derivatives were synthesized using an electrochemical procedure coupled with a Schiff base as a facile, efficient and practical method. The products have been characterized after purification by IR, {sup 1}H NMR, {sup 13}C NMR and ESI-MS{sup 2}.

  7. Enhanced Analgesic Properties and Reduced Ulcerogenic Effect of a Mononuclear Copper(II) Complex with Fenoprofen in Comparison to the Parent Drug: Promising Insights in the Treatment of Chronic Inflammatory Diseases

    PubMed Central

    Gumilar, Fernanda; Boeris, Mónica; Toso, Ricardo; Minetti, Alejandra

    2014-01-01

    Analgesic and ulcerogenic properties have been studied for the copper(II) coordination complex of the nonsteroidal anti-inflammatory drug Fenoprofen and imidazole [Cu(fen)2(im)2] (Cu: copper(II) ion; fen: fenoprofenate anion from Fenoprofen, im: imidazole). A therapeutic dose of 28?mg/kg was tested for [Cu(fen)2(im)2] and 21?mg/kg was employed for Fenoprofen calcium, administered by oral gavage in female mice to compare the therapeutic properties of the new entity. The acetic acid induced writhing test was employed to study visceral pain. The percentage of inhibition in writhing and stretching was 78.9% and 46.2% for the [Cu(fen)2(im)2] and Fenoprofen calcium, respectively. This result indicates that the complex could be more effective in diminishing visceral pain. The formalin test was evaluated to study the impact of the drugs over nociceptive and inflammatory pain. The complex is a more potent analgesic on inflammatory pain than the parent drug. Ulcerogenic effects were evaluated using a model of gastric lesions induced by hypothermic-restraint stress. Fenoprofen calcium salt caused an ulcer index of about 79?mm2 while the one caused by [Cu(fen)2(im)2] was 22?mm2. The complex diminished the development of gastric mucosal ulcers in comparison to the uncomplexed drug. Possible mechanisms of action related to both therapeutic properties have been discussed. PMID:25050353

  8. Hybrid scaffold bearing polymer-siloxane Schiff base linkage for bone tissue engineering.

    PubMed

    Nair, Bindu P; Gangadharan, Dhanya; Mohan, Neethu; Sumathi, Babitha; Nair, Prabha D

    2015-07-01

    Scaffolds that can provide the requisite biological cues for the fast regeneration of bone are highly relevant to the advances in tissue engineering and regenerative medicine. In the present article, we report the fabrication of a chitosan-gelatin-siloxane scaffold bearing interpolymer-siloxane Schiff base linkage, through a single-step dialdehyde cross-linking and freeze-drying method using 3-aminopropyltriethoxysilane as the siloxane precursor. Swelling of the scaffolds in phosphate buffered saline indicates enhancement with increase in siloxane concentration, whereas compressive moduli of the wet scaffolds reveal inverse dependence, owing to the presence of siloxane, rich in silanol groups. It is suggested that through the strategy of dialdehyde cross-linking, a limiting siloxane loading of 20 wt.% into a chitosan -gelatin matrix should be considered ideal for bone tissue engineering, because the scaffold made with 30 wt.% siloxane loading degrades by 48 wt.%, in 21 days. The hybrid scaffolds bearing Schiff base linkage between the polymer and siloxane, unlike the stable linkages in earlier reports, are expected to give a faster release of siloxanes and enhancement in osteogenesis. This is verified by the in vitro evaluation of the hybrid scaffolds using rabbit adipose mesenchymal stem cells, which revealed osteogenic cell-clusters on a polymer-siloxane scaffold, enhanced alkaline phosphatase activity and the expression of bone-specific genes, whereas the control scaffold without siloxane supported more of cell-proliferation than differentiation. A siloxane concentration dependent enhancement in osteogenic differentiation is also observed. PMID:25953575

  9. sup 15 N and sup 13 C NMR studies of ligands bound to the 280,000-dalton protein porphobilinogen synthase elucidate the structures of enzyme-bound product and a Schiff base intermediate

    SciTech Connect

    Jaffe, E.K.; Rajagopalan, J.S. (Univ. of Pennsylvania School of Dental Medicine, Philadelphia (USA)); Markham, G.D. (Fox Chase Cancer Center, Philadelphia, PA (USA))

    1990-09-11

    Porphobilinogen synthase (PBGS) catalyzes the asymmetric condensation of two molecules of 5-aminolevulinic acid (ALA). Despite the 280,000-dalton size of PBGS, much can be learned about the reaction mechanism through {sup 13}C and {sup 15}N NMR. The authors knowledge, these studies represent the largest protein complex for which individual nuclei have been characterized by {sup 13}C or {sup 15}N NMR. Here they extend their {sup 13}C NMR studies to PBGS complexes with (3,3-{sup 2}H{sub 2},3-{sup 13}C)ALA and report {sup 15}N NMR studies of ({sup 15}N)ALA bound to PBGS. As in their previous {sup 13}C NMR studies, observation of enzyme-bound {sup 15}N-labeled species was facilitated by deuteration at nitrogens that are attached to slowly exchanging hydrogens. For holo-PBGS at neutral pH, the NMR spectra reflect the structure of the enzyme-bound product porphobilinogen (PBG), whose chemical shifts are uniformly consistent with deprotonation of the amino group whose solution pK{sub a} is 11. Despite this local environment, the protons of the amino group are in rapid exchange with solvent. For methyl methanethiosulfonate (MMTS) modified PBGS, the NMR spectra reflect the chemistry of an enzyme-bound Schiff base intermediate that is formed between C{sub 4} of ALA and an active-site lysine. The {sup 13}C chemical shift of (3,3-{sup 2}H{sub 2},3-{sup 13}C)ALA confirms that the Schiff base is an imine of E stereochemistry. By comparison to model imines formed between ({sup 15}N)ALA and hydrazine or hydroxylamine, the {sup 15}N chemical shift of the enzyme-bound Schiff base suggests that the free amino group is an environment resembling partial deprotonation. Deprotonation of the amino group would facilitate formation of a Schiff base between the amino group of the enzyme-bound Schiff base and C{sub 4} of the second ALA substrate. This is the first evidence supporting carbon-nitrogen bond formation as the initial site of interaction between the two substrate molecules.

  10. Synthesis and characterization of iron(III), manganese(II), cobalt(II), nickel(II), copper(II) and zinc(II) complexes of salicylidene-N-anilinoacetohydrazone (H2L1) and 2-hydroxy-1-naphthylidene-N-anilinoacetohydrazone (H2L2).

    PubMed

    AbouEl-Enein, S A; El-Saied, F A; Kasher, T I; El-Wardany, A H

    2007-07-01

    Salicylidene-N-anilinoacetohydrazone (H(2)L(1)) and 2-hydroxy-1-naphthylidene-N-anilinoacetohydrazone (H(2)L(2)) and their iron(III), manganese(II), cobalt(II), nickel(II), copper(II) and zinc(II) complexes have been synthesized and characterized by IR, electronic spectra, molar conductivities, magnetic susceptibilities and ESR. Mononuclear complexes are formed with molar ratios of 1:1, 1:2 and 1:3 (M:L). The IR studies reveal various modes of chelation. The electronic absorption spectra and magnetic susceptibility measurements show that the iron(III), nickel(II) and cobalt(II) complexes of H(2)L(1) have octahedral geometry. While the cobalt(II) complexes of H(2)L(2) were separated as tetrahedral structure. The copper(II) complexes have square planar stereochemistry. The ESR parameters of the copper(II) complexes at room temperature were calculated. The g values for copper(II) complexes proved that the Cu-O and Cu-N bonds are of high covalency. PMID:17113342

  11. Synthesis, Characterisation and Antifungal Activities of Some New Copper(II) Complexes of Isomeric 3,5,7,7,10,12,14,14-Octamethyl-1,4,8,11-Tetraazacyclotetradecanes

    PubMed Central

    Hazari, Saroj K. S.; Dey, Benu K.; Das, Suvash C.

    1997-01-01

    Three isomeric Me8[14]anes, LA, LB and LC, undergo complexation with copper(II) salts to form a series of [CuLXn(H2O)x]Xy.(H2O)z complexes where L = LA, LB and LC; X = Cl, Br, NO3; n, x, y and z may have values of 0, 1 or 2. The complexes have been characterised on the basis of analytical, spectroscopic, magnetic and conductance data. Further, the X-ray crystal structure of one complex, [CuLB(OH2)2](NO3)2, has been determined. The antifungal activity of all three isomeric ligands and their complexes has been investigated against a range of phytopathogenic fungi. PMID:18475797

  12. Selective recognition of sulfate anions in a 95% ethanol solvent with a simple neutral salicylaldehyde dansyl hydrazine Schiff base tuned by Brønsted-Lowry acid-base reaction.

    PubMed

    Wei, Gao-Ning; Zhang, Jing-Li; Jia, Cang; Fan, Wei-Zhen; Lin, Li-Rong

    2014-07-15

    A new Schiff base compound, 5-(dimethylamino)-N'-(2-hydroxybenzylidene)naphthalene-1-sulfonohydrazide (R), has been synthesized, characterized, and employed as a selective fluorescence receptor for the recognition of sulfate anions. UV-vis absorption, fluorescence emission, (1)H NMR spectra and DFT calculation studies on the system have been carried out to determine the nature of the interactions between R and anions. The results reveal that the deprotonation of the phenol without the need of a strong base leads to the formation of a hydrogen-bonding complex with a -SO2-NH- group, which is responsible for the spectra changes. The deprotonation process for the selectivity recognition of sulfate can be tuned by the Brønsted-Lowry acid-base reaction in nonaqueous solutions, revealing that suitable phenolic hydroxyl acidity is the key factor for anion recognition selectivity. PMID:24667421

  13. Selective recognition of sulfate anions in a 95% ethanol solvent with a simple neutral salicylaldehyde dansyl hydrazine Schiff base tuned by Brønsted-Lowry acid-base reaction

    NASA Astrophysics Data System (ADS)

    Wei, Gao-Ning; Zhang, Jing-Li; Jia, Cang; Fan, Wei-Zhen; Lin, Li-Rong

    2014-07-01

    A new Schiff base compound, 5-(dimethylamino)-N?-(2-hydroxybenzylidene)naphthalene-1-sulfonohydrazide (R), has been synthesized, characterized, and employed as a selective fluorescence receptor for the recognition of sulfate anions. UV-vis absorption, fluorescence emission, 1H NMR spectra and DFT calculation studies on the system have been carried out to determine the nature of the interactions between R and anions. The results reveal that the deprotonation of the phenol without the need of a strong base leads to the formation of a hydrogen-bonding complex with a sbnd SO2sbnd NHsbnd group, which is responsible for the spectra changes. The deprotonation process for the selectivity recognition of sulfate can be tuned by the Brønsted-Lowry acid-base reaction in nonaqueous solutions, revealing that suitable phenolic hydroxyl acidity is the key factor for anion recognition selectivity.

  14. Tris(2,2'-azobispyridine) complexes of copper(II): X-ray structures, reactivities, and the radical nonradical bis(ligand) analogues.

    PubMed

    Maity, Suvendu; Kundu, Suman; Weyhermüller, Thomas; Ghosh, Prasanta

    2015-02-16

    Tris(abpy) complexes of types mer-[Cu(II)(abpy)3][PF6]2 (mer-1(2+)[PF6(–)]2) and ctc-[Cu(II)(abpy)2(bpy)][PF6]2 (ctc-2(2+)[PF6(–)]2) were successfully isolated and characterized by spectra and single-crystal X-ray structure determinations (abpy = 2,2?-azobispyridine; bpy = 2,2?-bipyridine). Reactions of mer-1(2+) and ctc-2(2+) ions with catechol, o-aminophenol, p-phenylenediamine, and diphenylamine (Ph–NH–Ph) in 2:1 molar ratio afford [CuI(abpy)2](+) (3(+)) and corresponding quinone derivatives. The similar reactions of [Cu(II)(bpy)3](2+) and [Cu(II)(phen)3](2+) with these substrates yielding [Cu(I)(bpy)2](+) and [Cu(I)(phen)2](+) imply that these complexes undergo reduction-induced ligand dissociation reactions (phen = 1,10-phenanthroline). The average ?N?N– lengths in mer-1(2+)[PF6(–)]2 and ctc-2(2+)[PF6(–)]2 are 1.248(4), while that in 3(+)[PF6(–)]·2CH2Cl2 is relatively longer, 1.275(2) Å, due to dCu ? ?azo* back bonding. In cyclic voltammetry, mer-1(2+) exhibits one quasi-reversible wave at ?0.42 V due to Cu(II)/Cu(I) and abpy/abpy(•–) couples and two reversible waves at ?0.90 and ?1.28 V due to abpy/abpy(•–) couple, while those of ctc-2(2+) ion appear at ?0.44, ?0.86, and ?1.10 V versus Fc(+)/Fc couple. The anodic 3(2+)/3(+) and the cathodic 3(+)/3 redox waves at +0.33 and ?0.40 V are reversible. The electron paramagnetic resonance spectra and density functional theory (DFT) calculations authenticated the existence of abpy anion radical (abpy(•–)) in 3, which is defined as a hybrid state of [Cu(I)(abpy(0.5•–))(abpy(0.5•–))] and [Cu(II)(abpy(•–))(abpy(•–))] states. 3(2+) ion is a neutral abpy complex of copper(II) of type [Cu(II)(abpy)2](2+). 3 exhibits a near-IR absorption band at 2400–3000 nm because of the intervalence ligand-to-ligand charge transfer, elucidated by time-dependent DFT calculations in CH2Cl2. PMID:25650719

  15. Mononuclear and tetranuclear compounds of yttrium and dysprosium ligated by a salicylic schiff-base derivative: synthesis, photoluminescence, and magnetism.

    PubMed

    Yadav, Munendra; Mereacre, Valeriu; Lebedkin, Sergei; Kappes, Manfred M; Powell, Annie K; Roesky, Peter W

    2015-02-01

    The Schiff-base (2-aminoethyl)hydroxybenzoic acid (H(2)L) as a proligand was prepared in situ from 3-formylsalicylic acid and ethanolamine (ETA). The mononuclear {[Y(HL)(4)][ETAH]·H(2)O} (1) and {[Dy(HL)(4)] [ETAH]·3MeOH·H(2)O} (2) and tetranuclear {[Y(4)(HL)(2)(L)(4)(?(3)-OH)(2)]·4MeOH·4H(2)O} (3), {[Dy4(HL)(2)(L)(4)(?(3)-OH)(2)]·5(MeOH)(2)·7H(2)O (4), and {[Dy(4)(HL)(8)(L)(2)]·4MeOH·(2)H(2)O}(5) rare-earth metal complexes of this ligand could be obtained as single-crystalline materials by the treatment of H(2)L in the presence of the metal salts [Ln(NO(3))(3)·(H(2)O)m] (Ln = Y, Dy). In the solid state, the tetranuclear compounds 3 and 4 exhibit butterfly structures, whereas 5 adopts a rectangular arrangement. Electrospray ionization mass spectrometry data of the ionic compounds 1 and 2 support single-crystal X-ray analysis. The yttrium compounds 1 and 3 show fluorescence with 11.5% and 13% quantum yield, respectively, whereas the quantum yield of the dysprosium complex 4 is low. Magnetic studies on the dysprosium compounds 4 and 5 suggest the presence of weak antiferromagnetic interactions between neighboring metal centers. Compound 4 shows single-molecule-magnet behavior with two relaxation processes, one with the effective energy barrier U(eff) = 84 K and the preexponential factor ?(0) = 5.1 × 10(-9) s. PMID:25238652

  16. Structurally Diverse Copper(II) Complexes of Polyaza Ligands Containing 1,2,3-Triazoles: Site Selectivity and Magnetic Properties

    E-print Network

    Weston, Ken

    (II) centers in three dinuclear complexes were analyzed via temperature-dependent magnetic susceptibility Selectivity and Magnetic Properties Pampa M. Guha, Hoa Phan, Jared S. Kinyon, Wendy S. Brotherton structural diversity, which includes mononuclear and dinuclear complexes as well as one-dimensional polymers

  17. Low temperature FTIR study of the Schiff base reprotonation during the M-to-bR backphotoreaction

    PubMed Central

    Takei, H.; Gat, Y.; Sheves, M.; Lewis, A.

    1992-01-01

    We have applied low temperature difference FTIR spectroscopy to investigate intermediates produced from the M intermediate upon blue light excitation (<480 nm). In agreement with an earlier report by Balashov and Litvin (1981), who studied these intermediates with low temperature visible absorption spectrophotometry, we have observed at least three stages in this backphotoreaction. The initial photoproduct is stable at 100 K, and two products of subsequent thermal reactions are observed upon raising the temperature to 130 and 160 K, respectively. The alterations in the C=N stretching mode of the Schiff base have been identified by isotopically labeling the retinal chromophore, and changes in C=O stretching modes of amino acid residues with acidic side chains have been investigated. Analysis of the C=N stretching mode shows that the Schiff base remains unprotonated after the photochemical reaction at 100 K. Moreover, there are two types of Schiff bases, presumably associated with different bR species, that become thermally reprotonated at 130 and 160 K, respectively. Bands associated with the C=O stretching modes suggest that Asp 85 rather than Asp 96 reprotonates the Schiff base during the M to bR backphotoreaction. This conclusion is consistent with earlier observations that the polarity of electrical signals during this photochemical back reaction is reversed as compared to the thermal regeneration of bR from M. PMID:19431867

  18. Dinuclear copper(II) complexes of a polybenzimidazole ligand: their structures and inductive roles in DNA condensation.

    PubMed

    Meng, Xianggao; Liu, Liang; Zhou, Chunshan; Wang, Li; Liu, Changlin

    2008-08-01

    The structures of two dinuclear Cu(II) complexes of dtpb were determined. They are shown to be capable of inducing DNA condensation into nanometer- and micrometer-scale particles under neutral conditions. PMID:18597421

  19. Crystal field theory and EPR parameters in D2d and C2v distorted tetrahedral copper(II) complexes

    Microsoft Academic Search

    Stanislaw K. Hoffmann; Janina Goslar

    1982-01-01

    Calculations of the orbital energy vs tetrahedral (D2d and C2v) distortion parameters are reported for copper complexes on the assumption of constant metal-ligand distance. The possible ground states of the complexes are considered and the respective spin Hamiltonian parameters vs distortion parameters dependences are calculated. Comparison with experiment led to good agreement: the relation between the orbital splittings and dihedral

  20. Stability constants of copper(II) mixed complexes with some 4-quinolone antibiotics and (N-N) donors

    Microsoft Academic Search

    Guillermo Mendoza-Díaz; Raul Perez-Alonso; Rafael Moreno-Esparza

    1996-01-01

    Studies of complexation equilibria of the antibiotic anions nalidixate and cinoxacinate with [Cu(phen)]2+ and [Cu(bipy)]2+ are reported. These studies indicate that the stability of this type of complex is strongly related to the metal environment. A correlation between the stability constants, determined here, with the sigma donation character of the ligand is proposed. This study shows that the stability constant