Sample records for copperii schiff-base complexes

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

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

    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 1.71-1.80 B.M. corresponding to one unpaired electron respectively. The formation constants and free energies were measured spectrophotometrically, at constant ionic strength 0.1 M (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.

  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. 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.

  4. Synthesis, Spectral, and Biological Properties of Copper(II) Complexes of Thiosemicarbazones of Schiff Bases Derived from 4-Aminoantipyrine and Aromatic Aldehydes

    PubMed Central

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

    2006-01-01

    We have synthesized a novel series of Schiff bases by condensation of 4-aminoantipyrine and various aromatic aldehydes followed by reaction with thiosemicarbazide. These thiosemicarbazones are potential ligands toward transition metal ions. The reaction of copper(II) salts with 4[N-(benzalidene)amino]antipyrinethiosemicarbazone (BAAPTS), 4[N-(4?-methoxybenzalidene) amino] antipyrinethiosemicarbozone (MBAAPTS), 4[N-(4?-dimethylamino benzalidene) amino] antipyrinethiosemicarbazone (DABAAPTS), and 4[N-(cinnamalidene) amino] antipyrinethiosemicarbazone (CAAPTS) resulted in the formation of solid complexes with the general composition CuX2 · (H2O)(L)(X = Cl, Br,NO3,NCS, or CH3COO; L = BAAPTS, MBAAPTS, DABAAPTS, or CAAPTS). These complexes were characterized through elemental analysis, molecular weight, electrical conductance, infrared, electronic spectra, and magnetic susceptibilities at room temperature. Copper(II) complexes with BAAPTS and MBAAPTS were screened for antibacterial and antifungal properties and have exhibited potential activity. Thermal stabilities of two representative complexes were also investigated. PMID:17497009

  5. 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.

  6. 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

  7. 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

  8. 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.

  9. Oxidation of phenyl propyne catalyzed by copper(II) complexes of a benzimidazolyl schiff base ligand: Effect of acid/base, oxidant, surfactant and morphology

    NASA Astrophysics Data System (ADS)

    Kumar, Ravinder; Mathur, Pavan

    2015-02-01

    Copper(II) complexes with a new N-Substituted benzimidazolyl schiff base ligand are used as catalyst for the oxidation of 1-phenyl propyne. The oxidation is carried out under mild conditions using stoichiometric amounts of oxidant and catalytic amounts of Cu(II) complex as catalyst. Effect of acid/base, oxidant, morphology and surfactant has been studied. Two major products of phenyl propyne oxidation are the ?-diketonic product and a terminal aldehyde. Diketone is the major product under acidic conditions while aldehyde formation is highest under basic conditions. The maximum conversion is found with the NO3- bound complex. GC-MS is used to find the percentage yields of products. SEM and PXRD of the reused complexes as catalyst suggest that morphology affects the catalytic efficiency.

  10. 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, 1H NMR, 13C 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

  11. 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.

  12. Synthesis, characterization and X-ray crystal structures of copper(II) and nickel(II) complexes with potentially hexadentate Schiff base ligands

    Microsoft Academic Search

    Ali Akbar Khandar; Seyed Abolfazl Hosseini-Yazdi; Seyed Amir Zarei

    2005-01-01

    Copper(II) and nickel(II) complexes of potentially N2O4 Schiff base ligands 2-({[2-(2-{2-[(1-{2-hydroxy-5-[2-phenyl-1-diazenyl]phenyl}methylidene)amino] phenoxy}ethoxy) phenyl]imino}methyl)4-[2-phenyl-1-diazenyl]phenol (H2L1) and 2-({[2-(4-{2-[(1-{2-hydroxy-5-[2-phenyl-1-diazenyl]phenyl}methylidene)amino] phenoxy}butoxy) phenyl]imino}methyl)4-[2-phenyl-1-diazenyl]phenol (H2L2) prepared of 5-phenylazo salicylaldehyde (1) and two various diamines 2-[2-(2-aminophenoxy)ethoxy]aniline (2) and 2-[4-(2-aminophenoxy)butoxy]aniline (3) were synthesized and characterized by a variety of physico-chemical techniques. The single-crystal X-ray diffractions are reported for CuL1 and NiL2. The CuL1 complex contains copper(II) in a

  13. Synthesis, Characterization and Thermal Studies of Mononuclear and Binuclear Complexes of Copper(II) with Schiff Bases Derived from 1Phenyl2,3-dimethyl-4-amino-5-pyrazolone

    Microsoft Academic Search

    Mehmet Tümer; Hüseyin Köksal; Selahattin Serin

    1996-01-01

    A series of copper(II) complexes with ligands derived from the Schiff base reaction of 1-phenyl-2,3-dimethyl-4-amino-5-pyrazolone with 4-hydroxysalicylaldehyde (LH), 3-methoxysalicylaldehyde (LH) and 2-hydroxynaphtaldehyde (LH) have been prepared. These complexes have been characterized by elemental analyses, magnetic susceptibility, infrared and electronic spectral data. Molar conductivities of the complexes at room temperature were measured. The conductivity values of the LH and LH complexes

  14. Synthesis and characterization of nickel(II) and copper(II) complexes with tetradentate Schiff base ligands

    Microsoft Academic Search

    Prasanta Bhowmik; Michael G. B. Drew; Shouvik Chattopadhyay

    2011-01-01

    The 1:1 condensation of 1,2-diaminopropane and 1-phenylbutane-1,3-dione at high dilution gives a mixture of two positional isomers of terdentate mono-condensed Schiff bases 6-amino-3-methyl-1-phenyl-4-aza-2-hepten-1-one (HAMPAH) and 6-amino-3,5-dimethyl-1-phenyl-4-aza-2-hexen-1-one (HADPAH). The mixture of the terdentate ligands has been used for further condensation with pyridine-2-carboxaldehyde or 2-acetylpyridine to obtain the unsymmetrical tetradentate Schiff base ligands. The tetradentate Schiff bases are then allowed to react

  15. 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

  16. Di-, tetra- and hexanuclear iron(III), manganese(II/III) and copper(II) complexes of Schiff-base ligands derived from 6-substituted-2-formylphenols.

    PubMed

    Lan, Yanhua; Novitchi, Ghenadie; Clérac, Rodolphe; Tang, Jin-Kui; Madhu, N T; Hewitt, Ian J; Anson, Christopher E; Brooker, Sally; Powell, Annie K

    2009-03-14

    Acyclic Schiff base ligands, derived from the condensation of 2,3-disubstituted benzaldehydes and 1,3-diaminopropan-2-ol, react with iron(II/III), manganese(II/III) and copper(II) salts to give di-, tetra- and hexanuclear complexes [Fe(III)(2)(L5)(2)].2MeOH (), [Fe(III)(4)(mu(3)-OMe)(2)(HL4)(2)Cl(2)] (), [Mn(II)(2)Mn(III)(2)(micro-OMe)(2)(HL4)(2)(DMF)(2)].2DMF () and [Cu(II)(6)(L5)(2)(micro(5)-SO(4))(2)(micro-SO(4))(MeOH)(2)].H(2)O.15.5(MeOH).15.5(MeCN) (). All compounds have been characterised by X-ray crystallography. Variable-temperature solid-state dc magnetisation studies have been performed in the temperature range 1.8-300 K. Antiferromagnetic interactions are present in all the compounds. The dinuclear compound has a zero total spin ground state with J = -9.66(1) cm(-1) and g = 2.07(1). The magnetic data for the tetranuclear compounds and have been interpreted using a tetranuclear butterfly model (b = body, w = wingtip) with the parameters: J(wb) = -9.35(4) cm(-1), J(bb) = -6.02(7) cm(-1), zJ' = -0.21(4) cm(-1) and g = 2.03(1) for ; and J(wb) = -3.40(3) cm(-1), J(bb) = -8.11(7) cm(-1), zJ' = -0.042(2) cm(-1) and g = 2.0 (fixed) for . The hexanuclear compound contains two {Cu(3)(L5)(MeOH)} units linked by three sulfate ligands: antiferromagnetic interactions are present in each trinuclear unit leading to two S = 1/2 motifs which do not or only very weakly interact across the sulfate bridges. PMID:19240905

  17. Synthesis, characterization, and tyrosinase biomimetic catalytic activity of copper(II) complexes with schiff base ligands derived from ?-diketones with 2-methyl-3-amino-(3 H)-quinazolin-4-one

    NASA Astrophysics Data System (ADS)

    Ramadan, Abd El-Motaleb M.; Ibrahim, Mohamed M.; Shaban, Shaban Y.

    2011-12-01

    A template condensation of ?-diketones (biacetyl, benzile and 2,3-pentanedione) with 2-methyl-3-amino-(3 H)-quinazolin-4-one (AMQ) in the presence of CuX 2 (X = Cl -, Br -, NO3- or ClO4-) resulted in the formation of tetradentate Schiff base copper(II) complexes of the type [CuLX]X and [CuL]X 2. Structural characterization of the complex species was achieved by several physicochemical methods, namely elemental analysis, electronic spectra, IR, ESR, molar conductivity, thermal analysis (TAG & DTG), and magnetic moment measurements. The stereochemistry, the nature of the metal chelates, and the catalytic reactivity are markedly dependent upon the type of counter anions and the ligand substituent within the carbonyl moiety. A square planar monomeric structure is proposed for the perchlorate, nitrate, and bromide complexes, in which the counter anions are loosely bonded to copper(II) ion. For the chloride complexes, the molar conductivities and the spectral data indicated that they have square-pyramidal environments around copper(II) center. The reported copper(II) complexes exhibit promising tyrosinase catalytic activity towards the hydroxylation of phenol followed by the aerobic oxidation of the resulting catechol. A linear correlation almost exists between the catalytic reactivity and the Lewis-acidity of the central copper(II) ion created by the donating properties of the parent ligand. The steric considerations could be accounted to clarify the difference in the catalytic activity of these functional models.

  18. Synthesis, spectroscopic characterization and antimicrobial activity of binuclear metal complexes of a new asymmetrical Schiff base ligand: DNA binding affinity of copper(II) complexes

    NASA Astrophysics Data System (ADS)

    Shebl, Magdy

    2014-01-01

    The 1:1 condensation of o-acetoacetylphenol and 1,2-diaminopropane under condition of high dilution gives the mono-condensed Schiff base, (E)-3-(1-aminopropan-2-ylimino)-1-(2-hydroxyphenyl)butan-1-one. The mono-condensed Schiff base has been used for further condensation with isatin to obtain the new asymmetrical dicompartmental Schiff base ligand, (E)-3-(2-((E)-4-(2-hydroxyphenyl)-4-oxobutan-2-ylideneamino) propylimino)indolin-2-one (H3L) with a N2O3 donor set. Reactions of the ligand with metal salts give a series of new binuclear complexes. The ligand and its metal complexes were characterized by elemental analyses, IR, 1H and 13C NMR, electronic, ESR and mass spectra, conductivity and magnetic susceptibility measurements as well as thermal analyses. The analytical and spectroscopic tools showed that the complexes can be formulated as: [(HL)(VO)2(SO4)(H2O)]·4H2O, [(HL)Fe2Cl4(H2O)3]·EtOH, [(HL)Fe2(ox)Cl2(H2O)3]·2H2O, [(L)M2(OAc)(H2O)m]·nH2O; M = Co, Ni or Cu, m = 4, 0 and n = 2, 3, [(HL)Cu2Cl]Cl·6H2O and [(L)(UO2)2(OAc)(H2O)3]·6H2O. The metal complexes exhibited octahedral geometrical arrangements except copper complexes that exhibited tetrahedral geometries and uranyl complex in which the metal ion is octa-coordinated. The Schiff base and its metal complexes were evaluated for antimicrobial activity against Gram positive bacteria (Staphylococcus aureus), Gram negative bacteria (Escherichia coli) and fungi (Candida albicans and Aspergillus flavus). The ligand and some of its complexes were found to be biologically active. The DNA-binding properties of the copper complexes (6 and 7) have been investigated by electronic absorption, fluorescence and viscosity measurements. The results obtained indicate that these complexes bind to DNA via an intercalation binding mode with an intrinsic binding constant, Kb of 1.34 × 104 and 2.5 × 104 M-1, respectively.

  19. Synthesis, characterization and X-ray crystal structures of Vanadium(IV), Cobalt(III), Copper(II) and Zinc(II) complexes derived from an asymmetric bidentate Schiff-base ligand at ambient temperature

    NASA Astrophysics Data System (ADS)

    Khorshidifard, Mahsa; Amiri Rudbari, Hadi; Kazemi-Delikani, Zahra; Mirkhani, Valiollah; Azadbakht, Reza

    2015-02-01

    An asymmetric bidentate Schiff-base ligand (HL: 2-((allylimino)methyl)phenol) was prepared from reaction of salicylaldehyde and Allylamine. Vanadium(IV), Cobalt(III), Copper(II) and Zinc(II) complexes, VOL2, CoL3, CuL2 and ZnL2 were synthesized from the reaction of VO(acac)2, CoCl2·6H2O, CuCl2·2H2O and Zn(NO3)2·6H2O with the bidentate Schiff base ligand (HL: 2-allyliminomethyl-phenol) in methanol at ambient temperature. The ligand and its metal complexes were characterized by elemental analysis (CHN), FT-IR spectroscopy. In addition, 1H and 13C NMR techniques were employed for characterization of the ligand (HL) and diamagnetic complex ZnL2. The molecular structures of all complexes were determined by single crystal X-ray diffraction technique. In the ZnL2 and CuL2 complexes, the metal ion is coordinated by two nitrogen and two oxygen atoms from two Schiff base ligands in an approximately square planar trans-[MN2O2] coordination geometry. In the Vanadium(IV) complex, VOL2, the vanadium center in this structure has a distorted tetragonal pyramidal N2O3 coordination sphere and for Cobalt(III) complex, CoL3, the CoIII ion is six coordinated by three bidentate Schiff base ligands in a distorted octahedral environment.

  20. 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

  1. 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.

  2. Association of structural modifications with bioactivity in three new copper(II) complexes of Schiff base ligands derived from 5-chlorosalicylaldehyde and amino acids.

    PubMed

    Li, Ang; Liu, Ya-Hong; Yuan, Ling-Zhi; Ma, Zhong-Ying; Zhao, Chun-Lai; Xie, Cheng-Zhi; Bao, Wei-Guo; Xu, Jing-Yuan

    2015-05-01

    Three novel structurally associated copper(II) complexes [Cu(II)(SalCl-Gly)(H2O)2] (1), [Cu(II)(SalCl-Ala)(H2O)] (2) and [Cu(II)(SalCl-Gly)(bipy)]·0.5H2O (3) (SalCl-Gly=5-chloro-2-hydroxybenzylidene-glycine, SalCl-Ala=5-chloro-2-hydroxybenzylidene-alanine, bipy=2,2'-bipyridine) have been synthesized and characterized by X-ray crystallography, elemental analysis, IR and fluorescence spectroscopy. Single-crystal diffraction reveals that complex 1 is an infinite 1D zigzag chain in which SalCl-Gly serves as both a chelating and a bridging ligand, while complexes 2 and 3 are mononuclear. Cu(II) ions in complexes 1-3 exhibit distorted quasi-hexacoordinated octahedral, tetracoordinated square planar, and pentacoordinated square pyramid geometry, respectively. Their interactions with calf thymus DNA (CT-DNA) have been investigated by viscosity measurements and fluorescence spectroscopy. The apparent binding constant (Kapp) values for 1-3 are 1.02×10(5), 0.98×10(5) and 1.57×10(5)M(-1), respectively. All complexes displayed efficient oxidative cleavage of supercoiled DNA in the presence of H2O2. Complex 2, whose ligand can be regarded as a methyl-modification of SalCl-Gly of 1, showed a reduced DNA cleavage activity and a little-changed DNA-binding ability compared with 1. While attaching a 2,2'-bipyridine group to 1, the resulting complex 3 was conferred an enhanced intercalation into DNA. Moreover, cytotoxicity studies of three complexes against HepG-2 (human liver hepatocellular carcinoma) and NCI-H460 (human large-cell lung carcinoma) cells indicated that, thereto, complex 3 possessed the highest inhibition on viability of tested cells. PMID:25771239

  3. Chelation and extraction of copper(II) with 5-pyrazolone-based Schiff bases

    Microsoft Academic Search

    N. J. Parmar; H. A. Barad; B. R. Pansuriya; R. A. Patel

    2011-01-01

    Copper(II) chelates of the Schiff bases (H2L), obtained by condensation of 4-butyryl-3-methyl-1-phenyl-pyrazoline-5-one (HBMPP) with o-phenylene diamine (H2L) and p-phenylene diamine (H2L), have been prepared and characterized by elemental analyses, thermogravimetric analyses, magnetic measurements, diffuse reflectance spectra, IR and mass spectra, and conductance measurements. The extractability of copper(II) with H2L in chloroform was examined. Effective extraction was observed with 1?×?10?mol?dm of

  4. Antifungal Activities of Copper(II) with Biosensitive Macrocyclic Schiff Base Ligands Derived from 4-Aminoantipyrine Derivatives

    PubMed Central

    Joseph, J.

    2009-01-01

    Novel copper(II) complexes have been synthesized from the macrocyclic Schiff bases derived from Knoevenagel condensed ?-ketoanilides (obtained by the condensation of acetoacetanilide and substituted benzaldehydes), 4-aminoantipyrine and o-phenylene diamine. The structural features have been determined from their analytical and spectral data. All the Cu(II) complexes exhibit square planar geometry. Their high molar conductance values support their 1 : 2 electrolytic nature. The magnetic moment data provide evidence for the monomeric nature of the complexes. The X-band ESR spectra of the [CuL1](OAc)2 in DMSO solution at 300 and 77 K were recorded and their salient features are reported. The in vitro biological screening effects of the investigated compounds were tested against the bacterial species Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Proteus vulgaris and Pseudomonas aeruginosa and fungal species Aspergillus niger, Rhizopus stolonifer, Aspergillus flavus, Rhizoctonia bataicola and Candida albicans by well diffusion method. A comparative study of inhibition values of the Schiff bases and their complexes indicate that complexes exhibit higher antimicrobial activity than the Schiff bases. Copper ions proved to be essential for the growth-inhibitor effect. The extent of inhibition appeared to be strongly dependent on the initial cell density and on the growth medium. PMID:23983523

  5. Enantioselective catalysis using lanthanide Schiff base complexes

    SciTech Connect

    Watkin, J.G. [Los Alamos National Laboratory, NM (United States)

    1996-10-01

    The use of lanthanide-based catalysts to facilitate organic transformations is currently an area of rapid growth, in particular the application of lanthanide alkoxide and triflate derivatives as effective Lewis-acidic catalysts for Michael additions and aldol reactions, and bis-pentamethylcyclopentadienyl derivatives as extremely active catalysts for hydrogenation and enantioselective hydroamination reactions. We have begun an investigation into the use of lanthanide complexes containing chiral alkoxide ligands as Lewis-acidic catalysts for enantioselective organic reactions. Since the large ionic radii of the lanthanide +III metal centers can often lead to oligomerization of simple alkoxide species, we have also examined the use of multidentate, chelating Schiff base ligands to provide an asymmetric environment about a lanthanide metal center. Structural investigations of the catalysts will be described, together with the use of these catalysts in enantioselective Meerwein-Ponndorf-Verley reduction of ketones and nitroaldol reactions.

  6. Formation of a novel ferromagnetic end-to-end cyanate bridged homochiral helical copper(II) Schiff base complex via spontaneous symmetry breaking.

    PubMed

    Bhattacharyya, Anik; Ghosh, Biswa Nath; Herrero, Santiago; Rissanen, Kari; Jiménez-Aparicio, Reyes; Chattopadhyay, Shouvik

    2015-01-14

    A homochiral helical coordination polymer of copper(II) has been synthesized using achiral precursors via spontaneous symmetry breaking and has been confirmed by single crystal X-ray diffraction and solid-state CD spectroscopy. The variable temperature magnetic measurements indicate the presence of weak ferromagnetic exchange interactions mediated by end-to-end cyanate bridges (J = +0.12 cm(-1)). PMID:25427985

  7. Cyclopalladated binuclear complexes of schiff bases

    Microsoft Academic Search

    K. Selvakumar; S. Vancheesan

    1996-01-01

    Refluxing palladium acetate with Schiff bases C6H5CH=NMe (1), C6H5CH=N Bun (2), 4-MeC6H4CH=NBun (3), 4-OCH3C6H4CH=NBun (4), 3,4-(OMe)2C6H3CH=N Bun (5) and 2,4-(OMe)2C6H3CH=NBun (6) in acetic acid followed by metathesis with LiCl on methanol gave chloro-bridged cyclopalladated complexes 1a–6a. The reactions of these chloro-bridged complexes with binucleating ligands such as 4,4?-bipyridine, 1,1,2,2-tetra-acetyl ethane,N,N?-bis(2-hydroxybenzylidene)-1 ,4-diaminobutane, N,N?-bis(2-hydroxy-3-t-butyl-5-methylbenzylidene)-1, 4-diaminobutane, N,N?-bis(2-hydroxy-5-methyl-?-phenyl-benzylidene)-1, 4-diaminobutane and 2-hydroxybenzalazine gave binuclear cyclopalla-dated

  8. Long Range Binuclear Copper(II) Chelates with Tetradentate Schiff Base Derived from Heterocyclic ?-Diketones and Aromatic Diamines

    Microsoft Academic Search

    B. T. Thaker; B. V. Patel; Purnima Thaker

    1991-01-01

    Copper(II) chlorides react with m-phenylenediamine or 2,6-diaminopyridine and 1-phenyl-3-methyl-4-benzoylpyrazolone-5 (HPmbzP) and its 4?-chloro, 4?-nitro derivatives or 1-phenyl-3-methyl-4-acetyl-pyrazolone-5 (HPmAcP) to form complexes of the general formulae [Cu(C40H31N6O2)] and [Cu(C39H30N7O2)] or [Cu(C30H27N6O2)] and [Cu(C29H26N7O2)]. The complexes are characterised to be distorted from square-planar to tetrahedral with the diamine moieties of the tetradentate Schiff base acting as bridges. The ligands coordinate through all

  9. Synthesis, characterization and antibacterial activity of a Schiff base derived from cephalexin and sulphathiazole and its transition metal complexes

    NASA Astrophysics Data System (ADS)

    Anacona, J. R.; Rodriguez, Juan Luis; Camus, Juan

    2014-08-01

    Metal(II) coordination compounds of a cephalexin Schiff base (HL) derived from the condensation of cephalexin antibiotic with sulphathiazole were synthesized. The Schiff base ligand, mononuclear [ML(OAc)(H2O)2] (M(II) = Mn, Co, Ni, Zn) complexes and magnetically diluted trinuclear copper(II) complex [Cu3L(OH)5] were characterized by several techniques, including elemental and thermal analysis, molar conductance and magnetic susceptibility measurements, electronic, FT-IR, EPR and 1H NMR spectral studies. The analytical and molar conductance values indicated that the acetate ions coordinate to the metal ions. The Schiff base ligand HL behaves as a monoanionic tridentate NNO and tetradentate NNOO chelating agent in the mono and trinuclear complexes respectively.

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

    NASA Astrophysics Data System (ADS)

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

    2015-02-01

    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 1H 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.

  11. 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

  12. Syntheses, crystal structure, spectroscopic and photoluminescence studies of mononuclear copper(II), manganese(II), cadmium(II), and a 1D polymeric Cu(II) complexes with a pyrimidine derived Schiff base ligand

    NASA Astrophysics Data System (ADS)

    Ray, Sangita; Konar, Saugata; Jana, Atanu; Das, Kinsuk; Dhara, Anamika; Chatterjee, Sudipta; Kar, Susanta Kumar

    2014-01-01

    The complexation behaviour of Schiff base ligand 2-((2-(4,6-dimethylpyrimidin-2-yl)hydrazono)methyl)phenol [HL] towards different metal centres is reported by the syntheses and characterization of three mononuclear Cu(II), Mn(II) and Cd(II) complexes, [Cu(L)(H2O)2](NO3)(H2O) (1), [Mn(L)2](CH3OH) (2), [Cd(L)2](CH3OH) (3) and a 1D polymeric Cu(II) complex, [Cu(L)(ClO4)(C2N2O2H)]n(CH3OH) (4) respectively. In the complexes 1-4 the deprotonated uninegative tridentate ligand serves as NNO donor where one pyrimidine ring N, the azomethine N and the salicyl hydroxyl oxygen atoms are coordinatively active. The complex 1 has almost square pyramidal geometry [? = 0.2081] whereas the metal centres maintain distorted octahedral geometry in the remaining three complexes 2-4. All the complexes are characterized by X-ray crystallography. The Cd(II) complex has considerable fluorescence while the rest of the complexes and the ligand molecule are fluorescent silent.

  13. 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.

  14. 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

  15. 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.

  16. Designed synthesis of copper(II) and nickel(II) complexes with a tridentate N2O donor Schiff base: Modulation of crystalline architectures through Csbnd H⋯? and anion⋯? interactions

    NASA Astrophysics Data System (ADS)

    Das, Mithun; Chattopadhyay, Shouvik

    2013-11-01

    Two copper(II) complexes, Cu(L1)Cl (1), Cu(L1)NCS (3) and two nickel(II) complexes Ni(L1)Cl (2), Ni(L1)NCS (4), where HL1 = 1-[(2-diethylamino-ethylimino)-methyl]-naphthalen-2-ol act as tridentate N2O donor ligand, have been prepared and characterized by elemental analysis, IR and UV-Vis spectroscopy and single crystal X-ray diffraction studies. The geometry of the central metal ion in each of the four complexes is square planar. The existence of Csbnd H⋯? interactions in 2 gives rise to one dimensional chain structure. Complex 3 shows two Csbnd H⋯? interactions and one anion⋯? interactions which leads to a two dimensional layer structure. Each mononuclear unit of 4 has two Csbnd H⋯? interactions along b axis to form a double strand one dimensional array of the molecules in crystal packing.

  17. Synthesis, structures and urease inhibition studies of Schiff base metal complexes derived from 3,5-dibromosalicylaldehyde.

    PubMed

    Cui, Yongming; Dong, Xiongwei; Li, Yuguang; Li, Zuowen; Chen, Wu

    2012-12-01

    Eleven mononuclear copper(II), nickel(II), zinc(II) and cobalt(II) complexes of Schiff base ligands derived from 3,5-dibromosalicylaldehyde/3,5-dichlorosalicylaldehyde were synthesized and determined by single crystal X-ray analysis. The crystal structures of complexes 1, 2, 4, 5, 6, 8 and 11 present the square-planar coordination geometry at the metal center and complexes 7, 9 and 10 show the distorted tetrahedral geometry. While one copper center in 3 has a square-planar geometry, the other copper is slightly distorted square-planar. The inhibitory activities of all the obtained complexes were tested in vitro against jack bean urease. It was found that Schiff base copper(II) complexes 1, 3, 5, 8 and 11 showed strong urease inhibitory activities (IC(50) = 1.51-3.52 ?M) compared with acetohydroxamic acid (IC(50) = 62.52 ?M), which was a positive reference. Their structure-activity relationships were further discussed. PMID:23142672

  18. 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.

  19. A dinuclear copper(II) complex and a zigzag chain iron(II) polymer based on the 4-antipyrine derived Schiff base ligands: The hydroxylation and redox occurred under the solvothermal conditions

    Microsoft Academic Search

    Xian-Wen Wang; Yue-Qing Zheng

    2007-01-01

    A new dinuclear copper(II) compound, [Cu2(L1-O)2] (1) (L1=(4E)-4-(2-hydroxybenzylideneamino)-1,2-dihydro-2,3-dimethyl-1-phenylpyrazol-5-one), and zigzag chain polymer, {[FeCl2(L2)]}n (2) (L2=1,5-dimethyl-2-phenyl-4-{[(1E)-pyridine-4-ylmethylene]amino}-1,2-dihydro-3H-pyrazol-3-one), were synthesized by solvothermal reactions and structurally characterized. The methyl group hydroxylation and the redox have been observed in the preparation of 1 and 2, respectively.

  20. Chromotropism Behavior and Biological Activity of some Schiff Base-Mixed Ligand Transition Metal Complexes

    Microsoft Academic Search

    Azza A. A. Abou-Hussen; Wolfgang Linert

    2009-01-01

    We report about a series of mono-nuclear and bi-nuclear complexes with acyclic as well as macro-cyclic ligands, which have been synthesized with Schiff base ligands in tri- tetra and pentadentate forms. The bonding sites on complex formation are mainly the azomethine groups and\\/or imide nitrogen, ketonic oxygen or sulphur atoms. Complexes of two series of Schiff base ligands, H2La and

  1. 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

  2. Hydrolysis of PNPP Catalyzed by Cu (II), Ni (II) Schiff Base Complexes in CTAB Micellar Solution

    Microsoft Academic Search

    Min Li; Dong Kou; Juan Du

    2007-01-01

    The kinetics of hydrolysis of p?nitrophenyl picolinate(PNPP) catalyzed by metallomicelles formed from Cu (II), Ni (II) Schiff base complexes (CuL, NiL) and CTAB micelle were investigated in the pH range of 6.0–9.0 at 30°C. For the Cu (II) Schiff base complex CuL, the apparent rate constants (kobsd) of PNPP hydrolysis initially increased with the increasing pH of reaction media, then

  3. 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.

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

    PubMed

    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. PMID:23978792

  5. Infrared and DNA-binding on ultraviolet and fluorescence spectra of new copper and zinc complexes with a naringenin Schiff-base ligand

    NASA Astrophysics Data System (ADS)

    Li, Yan-hua; Wang, Bao-dui; Yang, Zheng-yin

    2007-06-01

    A naringenin Schiff-base ligand (H 3L) and its copper(II) and zinc(II) complexes have been synthesized and characterized by elemental analyses, molar conductivities, 1H NMR, IR spectra, UV spectra and thermal analyses. The DNA-binding properties of the Cu(II) and Zn(II) complexes have been investigated by fluorescence spectroscopy, ultraviolet spectroscopy and by viscosity measurements. The results indicate that complexes and ligand may bind to DNA by intercalation modes, but the binding affinity of the complexes is much higher than that of the ligand.

  6. Synthesis, characterization and electrochemical study of synthesis of a new Schiff base (H2cdditbutsalen) ligand and their two asymmetric Schiff base complexes of Ni(II) and Cu(II) with NN'OS coordination spheres

    NASA Astrophysics Data System (ADS)

    Menati, Saeid; Azadbakht, Azadeh; Taeb, Abbas; Kakanejadifard, Ali; Khavasi, Hamid Reza

    2012-11-01

    A novel Schiff base (H2cdditbutsalen) ligand was prepared via condensation of Methyl-2-{N-(2'-aminoethane)}-amino-1-cyclopentenedithiocarboxylate(Hcden) and 3,5-di-tert-butyl-2-hydroxybenzaldehyde. The ligand and Ni(II) and Cu(II) complexes were characterized based on elemental analysis, IR, 1H NMR, 13C NMR, UV-Vis spectrometry and cyclic voltammetry. The structure of copper{methyl-2-{N-[2-(3,5-di-tert-butyl-2-hydroxyphenyl)methylidynenitrilo]ethyl}amino-1-cyclopentedithiocarboxylate has been determined by X-ray crystallography. The X-ray results confirm that the geometry of the complex is slightly distorted square-planar structure. The copper(II) ion coordinates to two nitrogen atoms from the imine moiety of the ligand, a sulfur atom the methyl dithiocarboxylate moiety and phenolic oxygen atom.

  7. Synthesis, characterization and electrochemical study of synthesis of a new Schiff base (H?cddi(t)butsalen) ligand and their two asymmetric Schiff base complexes of Ni(II) and Cu(II) with NN'OS coordination spheres.

    PubMed

    Menati, Saeid; Azadbakht, Azadeh; Taeb, Abbas; Kakanejadifard, Ali; Khavasi, Hamid Reza

    2012-11-01

    A novel Schiff base (H(2)cddi(t)butsalen) ligand was prepared via condensation of Methyl-2-{N-(2'-aminoethane)}-amino-1-cyclopentenedithiocarboxylate(Hcden) and 3,5-di-tert-butyl-2-hydroxybenzaldehyde. The ligand and Ni(II) and Cu(II) complexes were characterized based on elemental analysis, IR, (1)H NMR, (13)C NMR, UV-Vis spectrometry and cyclic voltammetry. The structure of copper{methyl-2-{N-[2-(3,5-di-tert-butyl-2-hydroxyphenyl)methylidynenitrilo]ethyl}amino-1-cyclopentedithiocarboxylate has been determined by X-ray crystallography. The X-ray results confirm that the geometry of the complex is slightly distorted square-planar structure. The copper(II) ion coordinates to two nitrogen atoms from the imine moiety of the ligand, a sulfur atom the methyl dithiocarboxylate moiety and phenolic oxygen atom. PMID:22925979

  8. Ruthenium(II) hydrazone Schiff base complexes: Synthesis, spectral study and catalytic applications

    NASA Astrophysics Data System (ADS)

    Manikandan, R.; Viswanathamurthi, P.; Muthukumar, M.

    2011-12-01

    Ruthenium(II) hydrazone Schiff base complexes of the type [RuCl(CO)(B)(L)] (were B = PPh 3, AsPh 3 or Py; L = hydrazone Schiff base ligands) were synthesized from the reactions of hydrazone Schiff base ligand (obtained from isonicotinoylhydrazide and different hydroxy aldehydes) with [RuHCl(CO)(EPh 3) 2(B)] (where E = P or As; B = PPh 3, AsPh 3 or Py) in 1:1 molar ratio. All the new complexes have been characterized by analytical and spectral (FT-IR, electronic, 1H, 13C and 31P NMR) data. They have been tentatively assigned an octahedral structure. The synthesized complexes have exhibited catalytic activity for oxidation of benzyl alcohol to benzaldehyde and cyclohexanol to cyclohexanone in the presence of N-methyl morpholine N-oxide (NMO) as co-oxidant. They were also found to catalyze the transfer hydrogenation of aliphatic and aromatic ketones to alcohols in KOH/Isopropanol.

  9. Manganese(III) Schiff-base complexes involving heterocyclic ?-diketone and diethylene triamine

    Microsoft Academic Search

    C. K. Modi; I. A. Patel; B. T. Thaker

    2008-01-01

    Synthesis, spectral, thermal and coordination aspects of pentadentate Schiff-base complexes of the type [Mn(L)(X)] · H2O [where H2L = N,N?–diethylamine bis(1-phenyl-3-methyl-4-acetylimino-2-pyrazoline-5-ol) and X=NCS, NO3, ClO4, CN or N3] are reported. The Schiff-base ligand (H2L) and metal complexes have been characterized by elemental analysis, FT-IR, H-NMR, magnetic measurements, molar conductivity measurements, electronic spectra, cyclic voltammetric and thermal studies. Magnetic moment values

  10. Some novel tetradentate Schiff base complexes VO(IV) and Cu(II) involving fluorinated heterocyclic ?-diketones and polymethylene diamines of varying chain length

    Microsoft Academic Search

    C. K. Modi; B. T. Thaker

    2008-01-01

    The present article describes the synthesis, spectral, coordination and thermal aspects of N,N?-polymethylene bis(1-phenyl-3-methyl-4-trifluoroacetylimino-2-pyrazoline-5-ol)oxovanadium(IV) or copper(II) Schiff base complexes with alkyl\\u000a backbones ranging from two to four carbons have been characterized on the basis of elemental analysis, magnetic moments, molar\\u000a conductivity measurements, spectra (FTIR, ESR, UV-Visible, MS), VPO and thermal studies. The vapour pressure osmometry (VPO)\\u000a and mass spectral studies

  11. Copper(II) complexes of schiff bases derived of 2-hydroxy-3-naphthaldehyde. The crystal and molecular structures of bis-{(phenyl)[(2-oxo-3 H -naphth-3-ylidene)methyl]aminato}copper(II) and bis-{(benzene-4-trifluoromethyl)[(2-oxo-3 H -naphth-3-ylidene)-methyl]aminato}copper(II)

    Microsoft Academic Search

    J. M. Fernández; J. J. Lembrino-Canales; R. Villena-I

    1994-01-01

    The Schiff base ligands, 3-[(Phenyl)-2-hydroxy-3H-Naphth-3-ylidene)methyl]aldamine (1) and 3-[(benzene-4-trifluoromethyl)-2-hydroxy-3H-naphth-3-ylidene)methyl]aldamine (2), and their corresponding Cu(II) complexes (I andII were synthesized. The crystal and molecular structures ofI andII were determined. CompoundI crystallizes in the triclinic crystal systema=10.804(5),b=12.589(5), andc=10.369(3) (Å), ?=107.72(3), ?=95.75(3), and ?=76.32(4)(°), in the space group P\\u000a

  12. Studies on synthesis, characterization, DNA interaction and cytotoxicity of ruthenium(II) Schiff base complexes

    NASA Astrophysics Data System (ADS)

    Raja, Gunasekaran; Butcher, Ray. J.; Jayabalakrishnan, Chinnasamy

    The synthesis and characterization of three hexa-coordinated ruthenium(II) Schiff base complexes of the type [RuCl(CO)(B)L] (B = PPh3/AsPh3/py and L = monobasic tridentate Schiff base ligand derived by the condensation of salicylaldehyde with 4-aminoantipyrine) are reported. IR, electronic, NMR and mass spectral data of the complexes are discussed. An octahedral geometry has been tentatively proposed for all the complexes. DNA binding properties of the ligand and its ruthenium(II) complexes have been investigated by electronic absorption spectroscopy. Two of the complexes were tested for DNA cleavage property. Finally, in vitro study of the cytotoxicity of the ligand and the complex [RuCl(CO)(PPh3)L] on HeLa were tested. The IC50 value for the ligand and the complex were 52.3 and 31.6 ?m respectively.

  13. Synthesis, characterization, thermal, and antimicrobial studies of binuclear metal complexes of sulfaguanidine Schiff bases

    Microsoft Academic Search

    Raafat M. Issa; Saleh A. Azim; Abdalla M. Khedr; Doaa F. Draz

    2009-01-01

    A series of metal complexes of Schiff bases derived from condensation of sulfa-guanidine with 1-benzoylacetone (H2L), 2-hydroxybenzophenol (H2L), dibenzoylmethane (H2L), 5-methylisatine (H2L), and 1-methylisatine (H2L) have been synthesized. The complexes are characterized by elemental analysis, molar conductance, magnetic moment measurements, IR, UV–Vis, H NMR, and ESR spectra, as well as thermogravimetric analysis. The low molar conductance values indicate the complexes

  14. Highly Ordered LB Films of a Novel Ferric Schiff Base Complex

    Microsoft Academic Search

    Kezhi Wang; Masa-Aki Haga; Hideaki Monjushiro

    1999-01-01

    An amphiphlic ferric Schiff base complex, FeLCl·2H2O (L = N,N?-bis-(1-phenyl-3-methyl-4-octadecylidene-pyrazone-5-one)ethylenediamine), is newly synthesized and characterized. Surface pressure-area isotherm on pure water subphase of the complex shows stable Langmuir film-formation. UV-visible spectroscopy and low-angle x-ray diffraction indicate that LB films transferred on hydrophilic glass are of highly ordered structure.

  15. New Azomethyne and Tetradentate Schiff Base Complexes of Transition Metals Containing Heterocyclic ?-Diketones as Ligands

    Microsoft Academic Search

    B. V. Patel; B. T. Thaker

    1986-01-01

    Several new azomethyne and tetradentate Schiff base complexes MA2.XH2O (M?Co(II), Ni(II) and Cu(II))have been synthesized where HA is 1-Phenyl-3-methyl-4-benzoylpyrazolone-5 (HPMBZP), a very stable asymmetric analogue of aliphatic ?-diketone. Characterization involved elemental analysis, conductivity measurements, IR, proton magnetic resonance spectra, magnetic susceptibility and melting points. The complexes are shown to be neutral chelates. IR and electronic spectral data together with band

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

    PubMed

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

    2015-06-15

    The platinum complexes of Schiff base ligands derived from 4-aminoantipyrine and a few substituted aldehydes were synthesized and characterized by elemental analysis, mass, (1)H 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(000)=352, Dc=1.405mg/m(3), ?=0.099mm(-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. PMID:25782179

  17. Spectroscopic studies and biological activity of some transition metal complexes of unusual Schiff base

    NASA Astrophysics Data System (ADS)

    Abu Al-Nasr, Ahmad K.; Ramadan, Ramadan M.

    2013-03-01

    Unusual Schiff base ligand, 4-ethanimidoyl-6-[(1E)-N-(2-hydroxy-4-methylphenyl)ethanimidoyl]benzene-1,3-diol, L, was synthesized via catalytic process involving the interaction of some metal ions with a macrocyclic Schiff base (MSB). The transition metal derivatives [ML(H2O)4](NO3)3, M = Cr(III) and Fe(III), [NiL(H2O)4](NO3)2, [ML(H2O)2](NO3)2, M = Zn(II) and Cd(II), [Cl2Pd(?-Cl)2PdL], [PtL(Cl)2] and [PtL(Cl)4] were also synthesized from the corresponding metal species with L. The Schiff bases and complexes were characterized by elemental analysis, mass spectrometry, IR and 1H NMR spectroscopy. The crystal structure of L was determined by X-ray analysis. The spectroscopic studies revealed a variety of structure arrangements for the complexes. The biological activities of L and metal complexes against the Escherchia coli as Gram-negative bacteria and Staphylococcus aureus as Gram-positive bacteria, and the two fungus Aspergillus flavus and Candida albicans were screened. The cytotoxicity of [PtL(Cl)2] complex, a cis-platin analogous, was checked as an antitumor agent on two breast cancer cell lines (MCF7 and T47D) and human liver carcinoma cell line (HepG2).

  18. Organotin(IV) complexes of Schiff bases derived by condensation of heterocyclic ketones and sulfa drugs

    Microsoft Academic Search

    H. L. Singh; M. K. Gupta; A. K. Varshney

    2001-01-01

    —Reaction of bis(triorganotin)oxide with Schiff bases derived by condensation of heterocyclic ketones, 2-acetylfuran and 2-acetylthiophene, with various sulfadrugs (sulfaguanidine, sulfathiazole, sulfisoxazole and sulfadiazine) leads to the formation of a new series of organotin(IV) complexes. An attempt has been made to probe their structures on the basis of elemental analysis, conductance measurements, molecular weight determination, UV, IR and NMR (1H, 13C

  19. Complexation Properties of Schiff Bases Containing the N-Phenylaza-15-crown-5 Moiety

    Microsoft Academic Search

    Liudmil Antonov; Maria Vladimirova; Elena Stanoeva; Walter M. F. Fabian; Loreto Ballester; Mariana Mitewa

    2001-01-01

    The complexation of a series of new Schiff bases containing theN-phenylaza-15-crown-5 (Ph-A15C5) moiety with alkali and alkaline-earth metal ions (incl. Be2+ and Mg2+, is studied by means of UV-Vis spectroscopy. The corresponding stability constant values are determined and discussed from two aspects: the position of the Ph-A15C5 moiety in the ligand molecule and the nature of the metal ion.

  20. One-dimensional organic photoconductive nanoribbons built on Zn-Schiff base complex

    SciTech Connect

    Liu Li [Anhui Key Laboratory of Functional Molecular Solids, College of Chemistry and Materials Science, Anhui Normal University, Wuhu 241000 (China); Department of Biochemical Engineering, Anhui University of Technology and Science, Wuhu 241000 (China); Shao Mingwang, E-mail: mwshao@mail.ahnu.edu.c [Anhui Key Laboratory of Functional Molecular Solids, College of Chemistry and Materials Science, Anhui Normal University, Wuhu 241000 (China); Functional Nano and Soft Materials Laboratory (FUNSOM), Soochow University, Suzhou 215123 (China); Wang Xiuhua [Anhui Key Laboratory of Functional Molecular Solids, College of Chemistry and Materials Science, Anhui Normal University, Wuhu 241000 (China)

    2010-03-15

    One-dimensional organic nanoribbons built on N-p-nitrophenylsalicylaldimine zinc complex were synthesized via a facile solvothermal route. The scanning electron microscope images revealed that the as-synthesized products were ribbon-like with width mainly of 300-600 nm, thickness of about 50 nm, and length of up to tens of micrometers. Fourier transform infrared spectrum was employed to characterize the structure. Ultraviolet-visible absorption and photoluminescence spectra showed that the products had good photoluminescent property and exhibited blue emission. The conductivity of a bundle of nanoribbons was also measured, which showed that the Schiff base zinc nanoribbons had good photoconductive property. This work might enrich the organic photoconductive materials and be applicable in light-controlled micro-devices or nano-devices in the future. - Graphical abstract: The Schiff base zinc nanoribbons nanowires exhibited good photoresponse under an incandescent lamp, which indicated their potential application as organic semiconductive or photoconductive nanodevices in the future.

  1. 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,

  2. Synthesis and Electrical Properties of Three Novel Poly(Ferrocenyl-Schiff Bases) and Their Charge Transfer Complexes with Iodine

    Microsoft Academic Search

    Wei-Jun Liu; Guo-Xuan Xiong; Dong-Hai Zeng

    2010-01-01

    Three ferrocenyl-Schiff base monomers were synthesized by the condensation of ferrocenecarboxaldehyde and phenylenediamine\\u000a under neutral conditions, and then used to produce copolymer materials with terephthaloyl chloride monomer by the Friedel–Crafts\\u000a method. The model compound and copolymers of three novel poly(ferrocenyl-Schiff bases) and their charge transfer complexes\\u000a with iodine were successful obtained and their structures were characterized by 1H-NMR, infrared, and

  3. Synthesis and spectral characterization of Cu(II) complexes of some thio-Schiff bases of acyl pyrazolone analogues

    Microsoft Academic Search

    Ravindra J. Yadav; Komal M. Vyas; R. N. Jadeja

    2010-01-01

    A series of tridentate pyrazolone-based thio-Schiff bases were synthesized by the interaction of 4-acyl\\/aroyl pyrazolones with thiosemicarbazide in an ethanolic medium. All of these ligands were characterized on the basis of elemental analysis, infrared (IR), H- and C-NMR data. Nuclear magnetic resonance (NMR) suggests the amine-one form of ligand in solution at room temperature. Copper Schiff-base complexes, [Cu(L)(H2O)], have been

  4. Synthesis and characterization of Ni(II), Cu(II) and Zn(II) complexes with new macrocyclic Schiff base ligands containing piperazine moiety

    NASA Astrophysics Data System (ADS)

    Keypour, Hassan; Arzhangi, Parisa; Rahpeyma, Nasibeh; Rezaeivala, Majid; Elerman, Yalcin; Büyükgüngör, Orhan; Valencia, Laura; Khavasi, Hamid Reza

    2010-08-01

    Two new macrocyclic Schiff base ligands L 1 and L 2 from [1 + 1] and [2 + 2] condensation reaction, respectively, have been obtained in a one-pot synthesis starting from 1,4-bis(2-formylphenyl)piperazine and 2,2-dimethyl-propylendiamine. Unfortunately, because of the low solubility of two products, we were unable to separate them effectively. Macrocyclic Schiff base complexes [NiL 1](ClO 4) 2, [CuL 1](ClO 4) 2 and [ZnL 1](ClO 4) 2 were prepared from the reaction of a mixture of L 1 and L 2 in the presence of nickel(II), copper(II) and zinc(II) metal ions, respectively. In all cases, only [1 + 1] condensation products were obtained and no metal complexes were isolated with the L 2 macrocycle. All of complexes have been characterized by elemental analysis, IR spectra, FAB-MS, conductivity measurements and in the case of Zn(II) complex by 1H and 13C NMR spectroscopy. Crystal structures of [NiL 1](ClO 4) 2 and [NiL 1'](ClO 4) 2 complexes have been also determined. The Ni(II) is coordinated to the ligand L 1 and L 1' by two nitrogen atoms of piperazine group and two nitrogen atoms of the imine groups, in a slightly distorted square-planar geometry.

  5. Antitumor activity of some diorganotin and tin(IV) complexes of Schiff bases.

    PubMed

    Saxena, A; Tandon, J P

    1983-05-01

    Some new di-n-butyltin and tin(IV) complexes of the type Bu2SnL, Bu2SnL2 and SnL2 (where L = anions of Schiff bases derived from S-substituted dithiocarbazates and fluoro-aniline) have been prepared and screened for their antitumor activity in P 388 Lymphocyte Leukaemia system. These complexes do not show any toxicity at low dose levels and display T/C values in the range 94-124. Di-n-butyltin complex derived from salicylaldehyde-S-methyl dithiocarbazate has been found to be the most active in this series. PMID:6850571

  6. Synthesis, DNA binding, and antimicrobial studies of novel metal complexes containing a pyrazolone derivative Schiff base

    Microsoft Academic Search

    Natarajan Raman; Ramaraj Jeyamurugan; Mariyyappan Subbulakshmi; Raja Boominathan; Chithu Ramakrishnan Yuvarajan

    2010-01-01

    A novel series of Co(II), Ni(II), Cu(II), Zn(II), and VO(IV) complexes has been synthesized from the Schiff base derived from\\u000a 4-[(3,4-dimethoxybenzylidene)amino]-1,5-dimethyl-2-phenyl-1,2-dihydropyrazol-3-one and 1,2-diaminobenzene. Structural features\\u000a were determined by analytical and spectral techniques. Binding of synthesized complexes with calf thymus DNA (CT DNA) was\\u000a studied by spectroscopic methods and viscosity measurements. Experimental results indicate that the complexes are able to\\u000a form

  7. 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.

  8. 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.

  9. 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

  10. 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

  11. Design, spectral characterization and biological studies of transition metal(II) complexes with triazole Schiff bases

    NASA Astrophysics Data System (ADS)

    Hanif, Muhammad; Chohan, Zahid H.

    2013-03-01

    A new series of three biologically active triazole derived Schiff base ligands L1-L3 have been synthesized in equimolar reaction of 3-amino-1H-1,2,4-triazole with pyrrol-2-carboxaldehyde, 4-bromo-thiophene-2-carboxaldehyde, and 5-iodo-2-hydroxy benzaldehyde. The prepared Schiff bases were used for further complex formation reaction with different metal elements like Co(II), Ni(II), Cu(II) and Zn(II) as chlorides by using a molar ratio of ligand:metal as 2:1. The structure and bonding nature of all the compounds were identified by their physical, spectral and analytical data. All the metal(II) complexes possessed an octahedral geometry except the Cu(II) complexes which showed a distorted octahedral geometry. All the synthesized compounds, were studied for their in vitro antibacterial, and antifungal activities, against four Gram-negative (Escherichia coli, Shigella sonnei, Pseudomonas aeruginosa and Salmonella typhi) and two Gram-positive (Bacillus subtilis and Staphylococcus aureus) bacterial strains and against six fungal strains (Trichophyton longifusus, Candida albicans, Aspergillus flavus, Microsporum canis, Fusarium solani and Candida glabrata) by using agar-well diffusion method. It has been shown that all the synthesized compounds showed moderate to significant antibacterial activity against one or more bacterial strains. In vitro Brine Shrimp bioassay was also carried out to investigate the cytotoxic properties of these compounds. The data also revealed that the metal complexes showed better activity than the ligands due to chelation/coordination.

  12. Synthesis, spectroscopic characterization and antibacterial studies of lanthanide(III) Schiff base complexes containing N, O donor atoms

    NASA Astrophysics Data System (ADS)

    Lekha, L.; Raja, K. Kanmani; Rajagopal, G.; Easwaramoorthy, D.

    2014-01-01

    A series of six Ln(III) Schiff base complexes, Pr(III), Sm(III), Gd(III), Tb(III), Er(III) and Yb(III), were synthesized using sodium salt of Schiff base, 2-[(5-bromo-2-hydroxy-benzylidene)-amino]-3-hydroxy-propionic acid, derived from L-serine and 5-bromosalicylaldehyde. These complexes having general formula [Ln(L)(NO3)2(H2O)]·NO3 were characterized by elemental analysis, conductivity measurements, UV-Vis, FT-IR, mass spectrometry and fluorescence studies. Elemental analysis and conductivity measurements suggest the complexes have a 1:1 stoichiometry. From the spectral studies it has been concluded that Ln(III) complexes display eight coordination. The Schiff base and its Ln(III) metal complexes have also been screened for their antibacterial activities by Agar diffusion method.

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

    NASA Astrophysics Data System (ADS)

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

    2014-01-01

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

  14. New palladium(II) complexes bearing pyrazole-based Schiff base ligands: synthesis, characterization and cytotoxicity.

    PubMed

    Abu-Surrah, Adnan S; Abu Safieh, Kayed A; Ahmad, Iman M; Abdalla, Maher Y; Ayoub, Mikdad T; Qaroush, Abdussalam K; Abu-Mahtheieh, Ahmad M

    2010-02-01

    Reactions of 5-hydrazino-1,3-dimethyl-4-nitro-1H-pyrazole (1) with substituted benzaldehydes (2-5) in methanol gave the new substituted benzaldehyde (1,3-dimethyl-4-nitro-1H-pyrazol-5-yl)hydrazone Schiff base ligands (6-9) benzaldehyde (1,3-dimethyl-4-nitro-1H-pyrazol-5-yl)hydrazone (H-BDH, 6), 2,3-dimethoxybenzaldehyde (1,3-dimethyl-4-nitro-1H-pyrazol-5-yl)hydrazone (MeO-BDH, 7), 4-chlorobenzaldehyde (1,3-dimethyl-4-nitro-1H-pyrazol-5-yl)hydrazone (Cl-BDH, 8), and 4-hydroxybenzaldehyde (1,3-dimethyl-4-nitro-1H-pyrazol-5-yl)hydrazone (OH-BDH, 9) in moderate to excellent yields. Reactions of these pyrazole-based Schiff bases with [PdCl(2)(NCPh)(2)] in acetone at room temperature gave the trans-palladium(II) complexes trans-[PdCl(2)(L)(2)] (10-13) (L=6-9). The isolated compounds were characterized by their physical properties, elemental analysis, IR-, MS (EI)- and NMR-spectroscopy. The cytotoxic effect of these complexes against the fast growing head and neck squamous carcinoma cells SQ20B and SCC-25 has been studied. The influence was dose dependent and varies by cell type. The complexes 11, 12, and 13 had higher clonogenic cytotoxic effect than cisplatin when tested on SQ20B cell line. PMID:19913953

  15. New 3,4-diaminobenzoic acid Schiff base compounds and their complexes: Synthesis, characterization and thermodynamics

    NASA Astrophysics Data System (ADS)

    Mohammadi, Khosro; Niad, Mahmood; Jafari, Tahereh

    2014-03-01

    Some new tetradentate Schiff base ligands (H3L) were prepared via condensation of 3,4-diaminobenzoic acid with 2-hydroxybenzaldehyde derivatives, such as 3,4-bis((E)-2,4-dihydroxybenzylideneamino)benzoic acid (H3L1), 3,4-bis((E)-2-hydroxy-3-methoxybenzylideneamino)benzoic acid (H3L2) and 3,4-bis((E)-5-bromo-2-hydroxybenzylideneamino)benzoic acid (H3L4). Additionally, a tetradentate Schiff base ligand 3,4-bis((E)-2-hydroxybenzylideneamino)benzoic acid (H3L3) and its complexes were synthesized. Their metal complexes of Co(II), Ni(II), Cu(II) and Zn(II) were prepared in good yields from the reaction of the ligands with the corresponding metal acetate. They were characterized based on IR, 1H NMR, Mass spectroscopy and UV-Vis spectroscopy. Also, the formation constants of the complexes were measured by UV-Vis spectroscopic titration at constant ionic strength 0.1 M (NaClO4), at 25 °C in dimethylformamide (DMF) as a solvent.

  16. Synthesis, Structural, and Biological Studies of Some Schiff Bases and Their Metal Complexes

    PubMed Central

    Mishra, A. P.; Soni, Monika

    2008-01-01

    New bidentate or tridentate Schiff bases and their VO(II) and Co(II) complexes formed by the condensation of methyl isobutyl ketone with nicotinamide (mna)/2-amino-4-chlorophenol (map) and 2-hydroxy acetophenone with nicotinamide (han)/isoniazide (hai). Physicochemical characterization has been carried out to determine the structure of the complexes. The FAB mass and thermal data show degradation pattern of the complexes. XRD analysis reveals that all the studied complexes crystallize as tetragonal crystal system. Some of the complexes have been screened for their antimicrobial activity by the well diffusion technique using DMSO as solvent on different species of pathogenic bacteria/fungi, that is, E. coli, S. aureus, S. fecalis, A. niger, T. polysporum, and their antimicrobial potency have been discussed. It has been found that all the complexes are antimicrobially active and show higher activity than the free ligand. Metal chelation affects significantly the antimicrobial/bioactive behavior of the organic ligands. PMID:18670613

  17. Biological and Spectral Studies of Newly Synthesized Triazole Schiff Bases and Their Si(IV), Sn(IV) Complexes

    PubMed Central

    Singh, Kiran; Puri, Parvesh; Kumar, Yogender; Sharma, Chetan; Aneja, Kamal Rai

    2011-01-01

    The Schiff bases HL1-3 have been prepared by the reaction of 5-bromothiophene-2-carboxaldehyde with 4-amino-5-mercapto-3-methyl/propyl/isopropyl-s-triazole, respectively. Organosilicon(IV) and organotin(IV) complexes of formulae (CH3)2MCl(L1-3), (CH3)2M(L1-3)2 were synthesized from the reaction of (CH3)2MCl2 and the Schiff bases in 1?:?1 and 1?:?2 molar ratio, where M = Si and Sn. The synthesized Schiff bases and their metal complexes have been characterized with the aid of various physicochemical techniques like elemental analyses, molar conductance, UV, IR, 1H, 13C, 29Si, and 119Sn NMR spectroscopy. Based on these studies, the trigonal bipyramidal and octahedral geometries have been proposed for these complexes. The ligands and their metal complexes have been screened in vitro against some bacteria and fungi. PMID:21826133

  18. 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.

  19. New palladium(II) complexes bearing pyrazole-based Schiff base ligands: Synthesis, characterization and cytotoxicity

    Microsoft Academic Search

    Adnan S. Abu-Surrah; Kayed A. Abu Safieh; Iman M. Ahmad; Maher Y. Abdalla; Mikdad T. Ayoub; Abdussalam K. Qaroush; Ahmad M. Abu-Mahtheieh

    2010-01-01

    Reactions of 5-hydrazino-1,3-dimethyl-4-nitro-1H-pyrazole (1) with substituted benzaldehydes (2–5) in methanol gave the new substituted benzaldehyde (1,3-dimethyl-4-nitro-1H-pyrazol-5-yl)hydrazone Schiff base ligands (6–9) benzaldehyde (1,3-dimethyl-4-nitro-1H-pyrazol-5-yl)hydrazone (H-BDH, 6), 2,3-dimethoxybenzaldehyde (1,3-dimethyl-4-nitro-1H-pyrazol-5-yl)hydrazone (MeO-BDH, 7), 4-chlorobenzaldehyde (1,3-dimethyl-4-nitro-1H-pyrazol-5-yl)hydrazone (Cl-BDH, 8), and 4-hydroxybenzaldehyde (1,3-dimethyl-4-nitro-1H-pyrazol-5-yl)hydrazone (OH-BDH, 9) in moderate to excellent yields. Reactions of these pyrazole-based Schiff bases with [PdCl2(NCPh)2] in acetone at room temperature gave the trans-palladium(II) complexes trans-[PdCl2(L)2

  20. Synthesis, characterization, crystal structure determination, thermal study and catalytic activity of a new oxidovanadium Schiff base complex

    NASA Astrophysics Data System (ADS)

    Grivani, Gholamhossein; Ghavami, Abbaseh; Ku?eráková, Monika; Dušek, Michal; Khalaji, Aliakbar Dehno

    2014-11-01

    A new bidentate ON Schiff base ligand of HL (HL = 5-nitro-2-hydroxybenzyl-2-furylmethyl) imine), was synthesized by simple condensation reaction of 5-nitro-2-hydroxybenzaldehyde and 2-furfurylamine. Then by reaction of a methanolic solutions of the HL and VO(acac)2 in the ratio of 2:1, a new oxidovanadium(IV) Schiff base complex of VOL2 was synthesized. The Schiff base ligand and its vanadyl Schiff base complex were characterized by FT-IR, UV-vis spectra and CHN analysis. Single crystals suitable for X-ray analysis were obtained in DMSO as a VOL2(DMSO) complex. The crystal structure of the VOL2(DMSO) was determined by the single-crystal X-ray analysis. The coordination geometry around the vanadium center can be described as a distorted octahedron formed by two phenolato oxygen and two imine nitrogen atoms of the two Schiff base ligands in the equatorial position, the oxygen atom of DMSO and the oxido ion coordinated in the axial position. Thermogravimetric analysis of the VOL2 showed that the formation of mixed vanadium oxides at 450 ?C. In addition, decomposition of the vanadyl Schiff base complex (VOL2) in air at 660 °C resulted in the formation of the V2O5 nano particles with the average size of 52 nm. The catalytic activity of the VOL2 complex was evaluated in the epoxidation of cyclooctene (90% conversion and 100% epoxide) and oxidation of methyl phenyl sulfide (100% conversion and 100% sulfoxide).

  1. The NMR and X-ray study of L-arginine derived Schiff bases and its cadmium complexes

    NASA Astrophysics Data System (ADS)

    Ko?odziej, B.; Grech, E.; Schilf, W.; Kamie?ski, B.; Pazio, A.; Wo?niak, K.

    2014-04-01

    The structure study of five Schiff bases derived from L-arginine (L-Arg) and 2-hydroxy carbonyl compounds were performed in both solution and solid state using NMR and X-ray methods. Both analytical methods applied to the solid state sample of two Schiff bases showed a significant difference in molecular structures of unsubstituted and 7-CH3 substituted compounds. This effect was explained as a steric interaction of methyl group. Additionally the structure of two Cd2+ complexes with some Schiff bases were determined by NMR methods in DMSO solution and in the solid state. On the base of heteronuclear NMR measurement (13C, 15N and 113Cd) it was possible to define the complexation site on nitrogen atom. The large set of spectral parameters: chemical shifts, homo- and heteronuclear coupling constants, were used in structure study.

  2. Preparation and characterization of new tetradentate Schiff base metal complexes and biological activity evaluation

    NASA Astrophysics Data System (ADS)

    Sadeek, S. A.; El-Attar, M. S.; Abd El-Hamid, S. M.

    2013-11-01

    A new Schiff base (N,N'-ethylene (bis 1-cyclopropyl-6-fluoro-4-oxo-7-(piperazine-1-yl)-quinoline-3-carboxylic acid) and its Zn(II), Zr(IV), Ce(IV) and U(VI) complexes were synthesized and characterized by elemental analysis, molar conductance, IR, UV-Vis, 1H NMR spectra, magnetic moment, thermal analysis as well as mass spectra. The IR results demonstrate that the tetradentate binding mode of the ligand involving azomethine nitrogen and carboxylato oxygen atoms. The calculated bond length and the bond stretching force constant, F(Udbnd O), values for UO2 bond are 1.744 Å and 654.49 N m-1. The antimicrobial activity of the synthesized ligand and its complexes were screened and the results showed that the metal complexes were found to be more active than free ligand.

  3. 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.

  4. 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,

  5. Spectroscopic investigations of new binuclear transition metal complexes of Schiff bases derived from 4,6-diacetylresorcinol and 3-amino-1-propanol or 1,3-diamino-propane

    NASA Astrophysics Data System (ADS)

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

    2007-11-01

    The bifunctional carbonyl compound; 4,6-diacetylresorcinol (DAR) serves as precursor for the formation of different Schiff base ligands, which are either di- or tetra-basic with two symmetrical sets of either O 2N or N 2O tridentate chelating sites. The condensation of 4,6-diacetylresorcinol with 3-amino-1-propanol (3-AP) or 1,3-diaminopropane (DAP), yields the corresponding hexadentate Schiff base ligands, abbreviated as H 4L a and H 2L b, respectively. The structures of these ligands were elucidated by elemental analyses, IR, mass, 1H NMR and electronic spectra. Reaction of the Schiff base ligands with copper(II), nickel(II), cobalt(II), zinc(II), cadmium(II), iron(III), chromium(III), vanadyl(IV) and uranyl(VI) ions in 1:2 molar ratio afforded the corresponding transition metal complexes. A variety of binuclear complexes for the metal complexes were obtained with the ligands in its di- or tetra-deprotonated forms. The structures of the newly prepared complexes were identified by elemental analyses, infrared, electronic, mass, 1H NMR and ESR spectra as well as magnetic susceptibility measurements and thermal gravimetric analysis (TGA). The bonding sites are the azomethine and amino nitrogen atoms, and phenolic and alcoholic oxygen atoms. The metal complexes exhibit different geometrical arrangements such as square planar, tetrahedral, square pyramid and octahedral arrangement.

  6. 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.

  7. A novel 1D chain of azido bridged copper(II) with a salen-type di-Schiff base ligand

    NASA Astrophysics Data System (ADS)

    Biswas, Saptarshi; Ghosh, Ashutosh

    2012-07-01

    One new complex of Cu(II), [(CuL)2Cu3(N3)6]n (1) has been synthesized by reacting the "ligand complex", [CuL] with copper acetate and sodium azide (NaN3) in methanol-water where the di-Schiff base ligand H2L = N,N'-bis(?-methylsalicylidene)-1,3-propanediamine. The X-ray single crystal structural analysis shows that complex 1 consists of an incomplete face-sharing double cube of four Cu(II) ions with the formula of [(CuL)2Cu2(N3)2]2+ which are connected by [Cu(N3)4]2- unit to form a novel 1D chain.

  8. 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.

  9. Synthesis, spectroscopic characterization and DNA nuclease activity of Cu(II) complexes derived from pyrazolone based NSO-donor Schiff base ligands

    NASA Astrophysics Data System (ADS)

    Vyas, Komal M.; Joshi, Rushikesh G.; Jadeja, R. N.; Ratna Prabha, C.; Gupta, Vivek K.

    2011-12-01

    Two neutral mononuclear Cu(II) complexes have been prepared in EtOH using Schiff bases derived from 4-toluoyl pyrazolone and thiosemicarbazide. Both the ligands have been characterized on the basis of elemental analysis, IR, 1H NMR, 13C NMR and mass spectral data. The molecular geometry of one of these ligands has been determined by single crystal X-ray study. It reveals that these ligands exist in amine-one tautomeric form in the solid state. Microanalytical data, Cu-estimation, molar conductivity, magnetic measurements, IR, UV-Visible, FAB-Mass, TG-DTA data and ESR spectral studies were used to confirm the structures of the complexes. Electronic absorption and IR spectra of the complexes suggest a square-planar geometry around the central metal ion. The interaction of complexes with pET30a plasmid DNA was investigated by spectroscopic measurements. Results suggest that the copper complexes bind to DNA via an intercalative mode and can quench the fluorescence intensity of EB bound to DNA. The interaction between the complexes and DNA has also been investigated by agarose gel electrophoresis, interestingly, we found that the copper(II) complexes can cleave circular plasmid DNA to nicked and linear forms.

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

    NASA Astrophysics Data System (ADS)

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

    2009-07-01

    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 all the metal chelates are non-electrolytes. IR spectra show that HL is coordinated to the metal ions in a uninegatively tridentate manner with NNO donor sites of the azomethine N, amino N and deprotonated caroxylic-O. From the magnetic and solid reflectance spectra, it is found that the geometrical structures of these complexes are octahedral. The thermal behaviour of these chelates shows that the hydrated complexes losses water molecules of hydration in the first step followed immediately by decomposition of the anions and ligand molecules in the subsequent steps. The activation thermodynamic parameters, such as, E*, ?H*, ?S* and ?G* are calculated from the DrTG curves using Coats-Redfern method. The synthesized ligands, in comparison to their metal complexes also were screened for their antibacterial activity against bacterial species, Escherichia Coli, Pseudomonas aeruginosa, Staphylococcus Pyogones and Fungi (Candida). The activity data show that the metal complexes to be more potent/antibacterial than the parent Shciff base ligand against one or more bacterial species.

  11. 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.

  12. Metal (II) Complexes Derived from Naphthofuran-2-carbohydrazide and Diacetylmonoxime Schiff Base: Synthesis, Spectroscopic, Electrochemical, and Biological Investigation

    PubMed Central

    Sumathi, R. B.; Halli, M. B.

    2014-01-01

    A new Schiff base and a new series of Co(II), Ni(II), Cu(II), Cd(II), and Hg(II) complexes were synthesized by the condensation of naphthofuran-2-carbohydrazide and diacetylmonoxime. Metal complexes of the Schiff base were prepared from their chloride salts of Co(II), Ni(II), Cu(II), Cd(II), and Hg(II) in ethanol. The ligand along with its metal complexes have been characterized on the basis of analytical data, IR, electronic, mass, 1HNMR, ESR spectral data, thermal studies, magnetic susceptibility, and molar conductance measurements. The nonelectrolytic behaviour of the complexes was assessed from the measured low conductance data. The elemental analysis of the complexes confirm the stoichiometry of the type CuL2Cl2 and MLCl2 where M = Ni(II), Co(II), Cd(II), and Hg(II) and L = Schiff base. The redox property of the Cu(II) complex was investigated by electrochemical method using cyclic voltammetry. In the light of these results, Co(II), Ni(II), and Cu(II) complexes are assigned octahedral geometry, Cd(II), and Hg(II) complexes tetrahedral geometry. 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 cleaving capacity of all the complexes was analysed by agarose gel electrophoresis method. PMID:24592203

  13. 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

  14. 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.

  15. 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

  16. 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.

  17. Two new heterodinuclear Schiff base complexes: synthesis, crystal structure and thermal studies.

    PubMed

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

    2015-02-25

    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 [Ni(II)Hg(II)] unit and [Zn(II)Ni(II)] 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 C-H···Cl-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. PMID:25233025

  18. Unsymmetrical Schiff base (ON) ligand on complexation with some transition metal ions: synthesis, spectral characterization, antibacterial, fluorescence and thermal studies.

    PubMed

    Ali, Omyma A M; El-Medani, Samir M; Abu Serea, Maha R; Sayed, Abeer S S

    2015-02-01

    A series of eight metal Schiff base complexes were synthesized by the thermal reaction of Cu(II), Ni(II), Fe(III), Co(II), Zn(II), Hg(II), La(III) or Sm(III) with a Schiff base "L" produced by the condensation of furfuraldehyde and 1,2-diaminobenzene. These compounds were characterized by elemental analysis, UV-Vis, FT-IR, molar conductance, mass spectrometry, thermal and fluorescence studies. The studies suggested the coordination of the ligand L to metal through azomethine imine nitrogen and furan oxygen atoms of Schiff base moiety. Thermogravimetric (TG/DTG) analyses data were studied and indicated high stability for all complexes and suggested the presence of lattice and/or coordinated water molecules in the complexes. Coats-Redfern method has been used to calculate the kinetic and thermodynamic parameters of the metal complexes. The spectral and thermal analysis reveal that all complexes have octahedral geometry except Cu(II) and Ni(II) complexes which can attain a square planner arrangements. The ligand and its complexes exhibited intraligand (?-?(?)) fluorescence and can potentially serve as photoactive materials. Both the ligand and its complexes have been screened for antibacterial activities. PMID:25448965

  19. 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.

  20. Unsymmetrical Schiff base (ON) ligand on complexation with some transition metal ions: Synthesis, spectral characterization, antibacterial, fluorescence and thermal studies

    NASA Astrophysics Data System (ADS)

    Ali, Omyma A. M.; El-Medani, Samir M.; Abu Serea, Maha R.; Sayed, Abeer S. S.

    2015-02-01

    A series of eight metal Schiff base complexes were synthesized by the thermal reaction of Cu(II), Ni(II), Fe(III), Co(II), Zn(II), Hg(II), La(III) or Sm(III) with a Schiff base "L" produced by the condensation of furfuraldehyde and 1,2-diaminobenzene. These compounds were characterized by elemental analysis, UV-Vis, FT-IR, molar conductance, mass spectrometry, thermal and fluorescence studies. The studies suggested the coordination of the ligand L to metal through azomethine imine nitrogen and furan oxygen atoms of Schiff base moiety. Thermogravimetric (TG/DTG) analyses data were studied and indicated high stability for all complexes and suggested the presence of lattice and/or coordinated water molecules in the complexes. Coats-Redfern method has been used to calculate the kinetic and thermodynamic parameters of the metal complexes. The spectral and thermal analysis reveal that all complexes have octahedral geometry except Cu(II) and Ni(II) complexes which can attain a square planner arrangements. The ligand and its complexes exhibited intraligand (?-??) fluorescence and can potentially serve as photoactive materials. Both the ligand and its complexes have been screened for antibacterial activities.

  1. 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

  2. DNA interaction with octahedral and square planar Ni(II) complexes of aspartic-acid Schiff-bases

    NASA Astrophysics Data System (ADS)

    Sallam, S. A.; Orabi, A. S.; Abbas, A. M.

    2011-12-01

    Ni(II) complexes of (S,E)-2-(2-OHbenzilydene)aspartic acid; (S,E)-2-(2,3-diOHbenzilydene)aspartic acid-; (S,E)-2-(2,4-diOH-benzilydene)aspartic acid; (S,E)-2-(2,5-diOHbenzilydene)aspartic acid and (S,E)-2-((2-OHnaphthalene-1-yl)methylene)aspartic acid Schiff-bases have been synthesized by template method in ethanol or ammonia media. They were characterized by elemental analyses, conductivity measurements, magnetic moment, UV, IR and 1H nmr spectra as well as thermal analysis (TG, DTG, DTA). The Schiff-bases are dibasic tridentate or tetradentate donors and the complexes have square planar and octahedral structures. The complexes decompose in two or three steps where kinetic and thermodynamic parameters of the decomposition steps were computed. The interactions of the formed complexes with FM-DNA were monitored by UV and fluorescence spectroscopy.

  3. Spectroscopic studies on two mono nuclear iron (III) complexes derived from a schiff base and an azodye

    SciTech Connect

    Mini, S., E-mail: sadasivan.v@gmail.com; Sadasivan, V., E-mail: sadasivan.v@gmail.com [University College, M G Road, Palayam, Thiruvananthapuram 695 034 Kerala (India); Meena, S. S., E-mail: ssingh@barc.gov.in; Bhatt, Pramod, E-mail: ssingh@barc.gov.in [Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India)

    2014-10-15

    Two new mono nuclear Fe(III) complexes of an azodye (ANSN) and a Schiff base (FAHP) are reported. The azodye is prepared by coupling diazotized 1-amino-2-naphthol-4-sulphonicacid with 2-naphthol and the Schiff base is prepared by condensing 2-amino-3-hydroxy pyridine with furfural. The complexes were synthesized by the reaction of FeCl{sub 3}Ðœ‡2H{sub 2}O with respective ligands. They were characterized on the basis of elemental analysis and spectral studies like IR, NMR, Electronic and M.ssbauer. Magnetic susceptibility and Molar conductance of complexes at room temperature were studied. Based on the spectroscopic evidences and other analytical data the complexes are formulated as[Fe(ANSN)Cl(H{sub 2}O){sub 2}] and [Fe(FAHP)Cl{sub 2}(H{sub 2}O){sub 2}].

  4. The complex extracellular domain regulates the deprotonation and reprotonation of the retinal Schiff base during the bacteriorhodopsin photocycle.

    PubMed

    Brown, L S; Váró, G; Hatanaka, M; Sasaki, J; Kandori, H; Maeda, A; Friedman, N; Sheves, M; Nedleman, R; Lanyi, J K

    1995-10-01

    During the L-->M reaction of the bacteriorhodopsin photocycle the proton of the retinal Schiff base is transferred to the anionic D85. This step, together with the subsequent reprotonation of the Schiff base from D96 in the M-->N reaction, results in the translocation of a proton across the membrane. The first of these critical proton transfers occurs in an extended hydrogen-bonded complex containing two negatively charged residues (D85 and D212), two positively charged groups (the Schiff base and R82), and coordinated water. We simplified this region by replacing D212 and R82 with neutral residues, leaving only the proton donor and acceptor as charged groups. The D212N/R82Q mutant shows essentially normal proton transport, but in the photocycle neither of this protein nor of the D212N/R82Q/D96N triple mutant does a deprotonated Schiff base (the M intermediate) accumulate. Instead, the photocycle contains only the K, L, and N intermediates. Infrared difference spectra of D212N/R82Q and D212N/R82Q/D96N demonstrate that although D96 becomes deprotonated in N, D85 remains unprotonated. On the other hand, M is produced at pH > 8, where according to independent evidence the L<==>M equilibrium should shift toward M. Likewise, M is restored in the photocycle when the retinal is replaced with the 14-fluoro analogue that lowers the pKa of the protonated Schiff base, and now D85 becomes protonated as in the wild type.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7548047

  5. Synthesis, characterization and antimicrobial activities of mixed ligand transition metal complexes with isatin monohydrazone Schiff base ligands and heterocyclic nitrogen base

    NASA Astrophysics Data System (ADS)

    Devi, Jai; Batra, Nisha

    2015-01-01

    Mixed ligand complexes of Co(II), Ni(II), Cu(II) and Zn(II) with various uninegative tridentate ligands derived from isatin monohydrazone with 2-hydroxynapthaldehyde/substituted salicylaldehyde and heterocyclic nitrogen base 8-hydroxyquinoline have been synthesized and characterized by elemental analysis, conductometric studies, magnetic susceptibility and spectroscopic techniques (IR, UV-VIS, NMR, mass and ESR). On the basis of these characterizations, it was revealed that Schiff base ligands existed as monobasic tridentate ONO bonded to metal ion through oxygen of carbonyl group, azomethine nitrogen and deprotonated hydroxyl oxygen and heterocyclic nitrogen base 8-hydroxyquinoline existed as monobasic bidentate ON bonded through oxygen of hydroxyl group and nitrogen of quinoline ring with octahedral or distorted octahedral geometry around metal ion. All the compounds have been tested in vitro against various pathogenic Gram positive bacteria, Gram negative bacteria and fungi using different concentrations (25, 50, 100, 200 ?g/mL) of ligands and their complexes. Comparative study of antimicrobial activity of ligands, and their mixed complexes indicated that complexes exhibit enhanced activity as compared to free ligands and copper(II) Cu(LIV)(Q)?H2O complex was found to be most potent antimicrobial agent.

  6. Synthesis, characterization and study of vanadyl tetradentate Schiff base complexes as catalyst in aerobic selective oxidation of olefins

    Microsoft Academic Search

    Davar M Boghaei; Sajjad Mohebi

    2002-01-01

    Novel vanadyl Schiff base complexes with the general formula VOLx (x=7–18) were synthesized and characterized by physicochemical methods. Only an orange polymeric form was obtained for VOL13, both brown polymeric and green monomeric forms were obtained for VOLx, x=16, 17. These observations suggest that in these complexes oxovanadium(IV) exhibit a coordination number of five. Systematic substitution on the ancillary ligand

  7. Synthesis and Characterization of Dioxo-uranium(VI) Complexes of Some Aroylhydrazines and Their Schiff Bases With Acetone

    Microsoft Academic Search

    Didarul A. Chowdhury; Mohammad N. Uddin; Akter H. Sarker

    Some dioxouranium(VI) bis-complexes of ligands (LH); benzoylhydrazine (BH), salicyloylhydrazine (SalH), nicotinoylhydrazine (NH) and their Schiff bases with acetone (L H); isopropylenebenzoylhydrazine (IPBH), isopropylenesalicyloylhydrazine (IPSalH), isopropylenenicotinoylhydrazine (IPNH) in their both keto and enol forms have been prepared. Magnetic moment, electronic and infra-red spectral data, conductance and elemental analyses help describing the possible stereochemistry of the prepared complexes.

  8. Theoretical spectroscopic study of seven zinc(II) complex with macrocyclic Schiff-base ligand

    NASA Astrophysics Data System (ADS)

    Sayin, Koray; Kariper, Sultan Erkan; Sayin, Tuba Alagöz; Karaka?, Duran

    2014-12-01

    Seven zinc complexes, which are [ZnL1]2+, [ZnL2]2+, [ZnL3]2+, [ZnL4]2+, [ZnL5]2+, [ZnL6]2+ and [ZnL7]2+, are studied as theoretically. Structural parameters, vibration frequencies, electronic absorption spectra and 1H and 13C NMR spectra are obtained for Zn(II) complexes of macrocyclic penta and heptaaza Schiff-base ligand. Vibration spectra of Zn(II) complexes are studied by using Density Functional Theory (DFT) calculations at the B3LYP/LANL2DZ. The UV-VIS and NMR spectra of the zinc complexes are obtained by using Time Dependent-Density Functional Theory (TD-DFT) method and Giao method, respectively. The agreements are found between experimental data of [ZnL5]2+, [ZnL6]2+ and [ZnL7]2+ complex ions and their calculated results. The geometries of complexes are found as distorted pentagonal planar for [ZnL1]2+, [ZnL2]2+ and [ZnL3]2+ complex ions, distorted tetrahedral for [ZnL4]2+ complex ion and distorted pentagonal bipyramidal for [ZnL5]2+, [ZnL6]2+ and [ZnL7]2+ complex ions. Ranking of biological activity is determined by using quantum chemical parameters and this ranking is found as: [ZnL7]2+ > [ZnL6]2+ > [ZnL5]2+ > [ZnL3]2+ > [ZnL2]2+ > [ZnL1]2+.

  9. Theoretical spectroscopic study of seven zinc(II) complex with macrocyclic Schiff-base ligand.

    PubMed

    Sayin, Koray; Kariper, Sultan Erkan; Sayin, Tuba Alagöz; Karaka?, Duran

    2014-12-10

    Seven zinc complexes, which are [ZnL(1)](2+), [ZnL(2)](2+), [ZnL(3)](2+), [ZnL(4)](2+), [ZnL(5)](2+), [ZnL(6)](2+) and [ZnL(7)](2+), are studied as theoretically. Structural parameters, vibration frequencies, electronic absorption spectra and (1)H and (13)C NMR spectra are obtained for Zn(II) complexes of macrocyclic penta and heptaaza Schiff-base ligand. Vibration spectra of Zn(II) complexes are studied by using Density Functional Theory (DFT) calculations at the B3LYP/LANL2DZ. The UV-VIS and NMR spectra of the zinc complexes are obtained by using Time Dependent-Density Functional Theory (TD-DFT) method and Giao method, respectively. The agreements are found between experimental data of [ZnL(5)](2+), [ZnL(6)](2+) and [ZnL(7)](2+) complex ions and their calculated results. The geometries of complexes are found as distorted pentagonal planar for [ZnL(1)](2+), [ZnL(2)](2+) and [ZnL(3)](2+) complex ions, distorted tetrahedral for [ZnL(4)](2+) complex ion and distorted pentagonal bipyramidal for [ZnL(5)](2+), [ZnL(6)](2+) and [ZnL(7)](2+) complex ions. Ranking of biological activity is determined by using quantum chemical parameters and this ranking is found as: [ZnL(7)](2+)>[ZnL(6)](2+)>[ZnL(5)](2+)>[ZnL(3)](2+)>[ZnL(2)](2+)>[ZnL(1)](2+). PMID:24967540

  10. Novel Organotin(IV) Schiff Base Complexes with Histidine Derivatives: Synthesis, Characterization, and Biological Activity

    PubMed Central

    Garza-Ortiz, Ariadna; Camacho-Camacho, Carlos; Sainz-Espuñes, Teresita; Rojas-Oviedo, Irma; Gutiérrez-Lucas, Luis Raúl; Gutierrez Carrillo, Atilano; Vera Ramirez, Marco A.

    2013-01-01

    Five novel tin Schiff base complexes with histidine analogues (derived from the condensation reaction between L-histidine and 3,5-di-tert-butyl-2-hydroxybenzaldehyde) have been synthesized and characterized. Characterization has been completed by IR and high-resolution mass spectroscopy, 1D and 2D solution NMR (1H, 13C??and 119Sn), as well as solid state 119Sn NMR. The spectroscopic evidence shows two types of structures: a trigonal bipyramidal stereochemistry with the tin atom coordinated to five donating atoms (two oxygen atoms, one nitrogen atom, and two carbon atoms belonging to the alkyl moieties), where one molecule of ligand is coordinated in a three dentate fashion. The second structure is spectroscopically described as a tetrahedral tin complex with four donating atoms (one oxygen atom coordinated to the metal and three carbon atoms belonging to the alkyl or aryl substituents), with one molecule of ligand attached. The antimicrobial activity of the tin compounds has been tested against the growth of bacteria in vitro to assess their bactericidal properties. While pentacoordinated compounds 1, 2, and 3 are described as moderate effective to noneffective drugs against both Gram-positive and Gram-negative bacteria, tetracoordinated tin(IV) compounds 4 and 5 are considered as moderate effective and most effective compounds, respectively, against the methicillin-resistant Staphylococcus aureus strains (Gram-positive). PMID:23864839

  11. Novel Organotin(IV) Schiff Base Complexes with Histidine Derivatives: Synthesis, Characterization, and Biological Activity.

    PubMed

    Garza-Ortiz, Ariadna; Camacho-Camacho, Carlos; Sainz-Espuñes, Teresita; Rojas-Oviedo, Irma; Gutiérrez-Lucas, Luis Raúl; Gutierrez Carrillo, Atilano; Vera Ramirez, Marco A

    2013-01-01

    Five novel tin Schiff base complexes with histidine analogues (derived from the condensation reaction between L-histidine and 3,5-di-tert-butyl-2-hydroxybenzaldehyde) have been synthesized and characterized. Characterization has been completed by IR and high-resolution mass spectroscopy, 1D and 2D solution NMR ((1)H, (13)C??and (119)Sn), as well as solid state (119)Sn NMR. The spectroscopic evidence shows two types of structures: a trigonal bipyramidal stereochemistry with the tin atom coordinated to five donating atoms (two oxygen atoms, one nitrogen atom, and two carbon atoms belonging to the alkyl moieties), where one molecule of ligand is coordinated in a three dentate fashion. The second structure is spectroscopically described as a tetrahedral tin complex with four donating atoms (one oxygen atom coordinated to the metal and three carbon atoms belonging to the alkyl or aryl substituents), with one molecule of ligand attached. The antimicrobial activity of the tin compounds has been tested against the growth of bacteria in vitro to assess their bactericidal properties. While pentacoordinated compounds 1, 2, and 3 are described as moderate effective to noneffective drugs against both Gram-positive and Gram-negative bacteria, tetracoordinated tin(IV) compounds 4 and 5 are considered as moderate effective and most effective compounds, respectively, against the methicillin-resistant Staphylococcus aureus strains (Gram-positive). PMID:23864839

  12. Antioxidant, electrochemical, thermal, antimicrobial and alkane oxidation properties of tridentate Schiff base ligands and their metal complexes

    NASA Astrophysics Data System (ADS)

    Ceyhan, Gökhan; Çelik, Cumali; Uru?, Serhan; Demirta?, ?brahim; Elmasta?, Mahfuz; Tümer, Mehmet

    2011-10-01

    In this study, two Schiff base ligands (HL 1 and HL 2) and their Cu(II), Co(II), Ni(II), Pd(II) and Ru(III) metal complexes were synthesized and characterized by the analytical and spectroscopic methods. Alkane oxidation activities of the metal complexes were studied on cyclohexane as substrate. The ligands and their metal complexes were evaluated for their antimicrobial activity against Corynebacterium xerosis, Bacillus brevis, Bacillus megaterium, Bacillus cereus, Mycobacterium smegmatis, Staphylococcus aureus, Micrococcus luteus and Enterococcus faecalis (as Gram-positive bacteria) and Pseudomonas aeruginosa, Klebsiella pneumoniae, Escherichia coli, Yersinia enterocolitica, Klebsiella fragilis, Saccharomyces cerevisiae, and Candida albicans (as Gram-negative bacteria). The antioxidant properties of the Schiff base ligands were evaluated in a series of in vitro tests: 1,1-diphenyl-2-picrylhydrazyl (DPPH rad ) free radical scavenging and reducing power activity of superoxide anion radical generated non-enzymatic systems. Electrochemical and thermal properties of the compounds were investigated.

  13. New tetradentate Schiff bases of 2,2-dimethyl-1,3-diaminopropane and acetylacetone derivatives and their vanadyl complexes.

    PubMed

    Mohammadi, Khosro; Rastegari, Mina

    2012-11-01

    A series of new VO(IV) complexes with two new tetradentate Schiff base of 4,4'-(2,2-dimethylpropane-1,3-diyl)-bis(azan-1-yl-1-yldene)dipent-2-en-2-ol) [H(2)L(1)] and 3,3'-(2,2-dimethylpropane-1,3-diyl)azan-1-yl-1-ylidene)-bis(1-phenylbut-1-en-1-ol) [H(2)L(2)] (which have been derived from 2,2-dimethyl-1,3-diaminopropan, and diketones of acetylacetone and benzoylacetone) were synthesized and characterized by (1)H NMR, (13)C NMR, FT-IR, mass and UV-Vis spectrophotometry. The electrochemical properties of the vanadyl complexes were investigated by means of cyclic voltammetry. The oxidation potentials are increased by increasing the electron-withdrawing properties of functional groups of the Schiff base ligands according to the trend of Mecomplexes were carried out in the range of 20-700°C. The complexes were decomposed in two stages. Also, decomposition of the synthesized complexes is related to the Schiff base characteristics. The thermal decomposition of the studied reactions was first order. The kinetic parameters for the decomposition steps in vanadyl complexes thermograms have been calculated. PMID:22885931

  14. Metal-Based Biologically Active Compounds: Synthesis, Spectral, and Antimicrobial Studies of Cobalt, Nickel, Copper, and Zinc Complexes of Triazole-Derived Schiff Bases

    PubMed Central

    Singh, Kiran; Kumar, Yogender; Puri, Parvesh; Sharma, Chetan; Aneja, Kamal Rai

    2011-01-01

    A series of cobalt, nickel, copper, and zinc complexes of bidentate Schiff bases derived from the condensation reaction of 4-amino-5-mercapto-3-methyl/ethyl-1,2,4-triazole with 2,4-dichlorobenzaldehyde were synthesized and tested as antimicrobial agents. The synthesized Schiff bases and their metal complexes were characterized with the aid of elemental analyses, magnetic moment measurements, spectroscopic and thermogravimetric techniques. The presence of coordinated water in metal complexes was supported by infrared and thermal gravimetric studies. A square planar geometry was suggested for Cu(II) and octahedral geometry proposed for Co(II), Ni(II), and Zn(II) complexes. The Schiff bases and their metal complexes have been screened for antibacterial (Pseudomonas aeruginosa, Bacillus subtilis) and antifungal activities (Aspergillus niger, A. flavus). The metal complexes exhibited significantly enhanced antibacterial and antifungal activity as compared to their simple Schiff bases. PMID:22216017

  15. Synthesis, spectral, and thermal studies of oxomolybdenum(V) Schiff-base complexes derived from heterocyclic ?-diketone

    Microsoft Academic Search

    B. T. Thaker; R. S. Barvalia

    2010-01-01

    Six mononuclear Mo(V) Schiff-base complexes were prepared by the reaction of MoCl5 with Schiff bases, namely HL–HL and HL–HL, such as 5-hydroxy-3-methyl-1(2-chloro)phenyl-1H-pyrazolone-4-carbaldehyde (I), 5-hydroxy-3-methyl-1(3-chloro)phenyl-1H-pyrazolone-4-carbaldehyde (II), and 5-hydroxy-3-methyl-1(3-sulfoamido)phenyl-1H-pyrazolone-4-carbaldehyde (III) with ethanolamine and propanolamine, respectively, in aqueous ethanolic medium. The resulting complexes have been characterized by elemental analyses, molar conductance, FT-IR, H-NMR, electronic, electron spin resonance (ESR) spectra, magnetic susceptibility, and thermal

  16. Self-enhanced electrogenerated chemiluminescence of ruthenium(II) complexes conjugated with Schiff bases.

    PubMed

    Li, Panpan; Jin, Zhaoyu; Zhao, Meilian; Xu, Yanxue; Guo, Yong; Xiao, Dan

    2015-02-01

    In this work, we obtain two ruthenium(ii) complexes with Schiff base cavities that exhibit significantly enhanced electrochemiluminescence (ECL) intensity and quantum efficiency due to Ru(bpy)3(2+) in aqueous solution, without the addition of tri-n-propylamine (TPrA). The great increase in ECL intensity is confirmed to be due to the electrochemical oxidation of phenolic hydroxyl groups and the resonant structure of imino radicals. Thus, the electrons are transferred intramolecularly to the Ru(iii) center, leading to efficient generation of the excited state of Ru(ii)*. Subsequently, we find that Co(2+) bonding with the salen cavity can selectively and quickly quench the ECL signal. Furthermore, we study the mechanism of the process by which Co(2+) hinders the oxidation of phenolic groups and blocks the electron transfer from imino radicals to the Ru center. Thus, a highly sensitive and selective ECL probe for the recognition of Co(2+) was developed with a stable response over a concentration range of 0.9 ?M to 6.3 ?M and a detection limit as low as 21 nM. PMID:25515350

  17. Synthesis, Spectroscopic, Molecular Structure, and Antibacterial Studies of Dibutyltin(IV) Schiff Base Complexes Derived from Phenylalanine, Isoleucine, and Glycine

    PubMed Central

    Singh, Har Lal; Singh, Jangbhadur

    2014-01-01

    New series of organotin(IV) complexes and Schiff bases derived from amino acids have been designed and synthesized from condensation of 1H-indole-2,3-dione, 5-chloro-1H-indole-2,3-dione, and ?-amino acids (phenylalanine, isoleucine, and glycine). All compounds are characterized by elemental analyses, molar conductance measurements, and molecular weight determinations. Bonding of these complexes is discussed in terms of their UV-visible, infrared, and nuclear magnetic resonance (1H, 13C, and 119Sn NMR) spectral studies. The results suggest that Schiff bases behave as monobasic bidentate ligands and coordinate with dibutyltin(IV) in octahedral geometry according to the general formula [Bu2Sn(L)2]. Elemental analyses and NMR spectral data of the ligands with their dibutyltin(IV) complexes agree with their proposed distorted octahedral structures. Few representative compounds are tested for their in vitro antibacterial activity against Gram-positive (B. cereus, Staphylococcus spp.) and Gram-negative (E. coli, Klebsiella spp.) bacteria. The results show that the dibutyltin complexes are more reactive with respect to their corresponding Schiff base ligands. PMID:25525422

  18. Efficient red electroluminescent devices with sterically hindered phosphorescent platinum(II) Schiff base complexes and iridium complex codopant.

    PubMed

    Zhou, Liang; Kwong, Chun-Lam; Kwok, Chi-Chung; Cheng, Gang; Zhang, Hongjie; Che, Chi-Ming

    2014-10-01

    Sterically hindered platinum(II) Schiff base complexes were prepared. Complex 4, which displays red emission with a quantum yield of 0.29 in a thin film and a self-quenching rate constant of 1×10(-7) dm(3) mol(-1) ?s(-1), was used to fabricate organic light-emitting diodes with single or double emissive layers (EMLs). An iridium(III) complex with a wide band gap was codoped into the electron-dominant EML to act as a deep electron trapper, and red-light-emitting devices with the highest current, power, and external quantum efficiencies of 20.43?cd?A(-1) 18.33?Lm?W(-1), and 11.7%, respectively, were fabricated. A high current efficiency and EQE of up to 14.69?cd?A(-1) and 8.3%, respectively, were achieved at a high brightness of 1000?cd?m(-2). The significant delay of efficiency roll-off is attributed to the bulky 3D structure of the norbornene moiety at the periphery of the Schiff base ligand of 4 and to the new device design strategy. The fabricated device had a projected lifetime (LT50) of 18,000?h. PMID:25145872

  19. 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.

  20. 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

  1. 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

    justifies the detailed study of the chemicals and procedures involved with this chemistry. This current work concentrates on the fundamental study of transition metal Schiff base complexes that have shown a great deal of promise in their ability to catalyze...

  2. Adherence to Bürgi–Dunitz stereochemical principles requires significant structural rearrangements in Schiff-base formation: insights from transaldolase complexes

    PubMed Central

    Light, Samuel H.; Minasov, George; Duban, Mark-Eugene; Anderson, Wayne F.

    2014-01-01

    The Bürgi–Dunitz angle (?BD) describes the trajectory of approach of a nucleophile to an electrophile. The adoption of a stereoelectronically favorable ?BD can necessitate significant reactive-group repositioning over the course of bond formation. In the context of enzyme catalysis, interactions with the protein constrain substrate rotation, which could necessitate structural transformations during bond formation. To probe this theoretical framework vis-à-vis biocatalysis, Schiff-base formation was analysed in Francisella tularensis trans­aldolase (TAL). Crystal structures of wild-type and Lys?Met mutant TAL in covalent and noncovalent complexes with fructose 6-­phosphate and sedoheptulose 7-phosphate clarify the mechanism of catalysis and reveal that substrate keto moieties undergo significant conformational changes during Schiff-base formation. Structural changes compelled by the trajectory considerations discussed here bear relevance to bond formation in a variety of constrained enzymic/engineered systems and can inform the design of covalent therapeutics. PMID:24531488

  3. Synthesis, spectroscopic characterization, molecular modeling and potentiometric studies of Co(II), Ni(II), Cu(II) and Zn(II) complexes with 1,1-diaminobutane-Schiff base

    NASA Astrophysics Data System (ADS)

    Alaghaz, Abdel-Nasser M. A.

    2014-08-01

    Complexes of cobalt(II), nickel(II), copper(II) and zinc(II) of general composition [M(L)(H2O)2]·2H2O have been synthesized [L = N,N";-bis(2-hydroxybenzylidene)-1,1-diaminobutane]. The elemental analysis, molar conductance measurements, magnetic susceptibility measurements, mass, IR, UV, NMR, SEM, EDX, thermal and EPR spectral studies of the compounds led to the conclusion that the ligand acts as a tetradentate manner. The molar conductance of the complexes in fresh solution of DMSO lies in the range of 7.46-9.13 ?-1 cm2 mol-1 indicating their non-electrolytic behavior. On the basis of analytical and spectroscopic techniques, octahedral geometry of the complexes was proposed. The Schiff base acts as tetradentate ligand, coordinated through deprotonated phenolic oxygen and azomethine nitrogen atoms. The ligand field parameters were calculated for Co(II), Ni(II) and Cu(II) complexes and their values were found in the range reported for a octahedral structure. The molecular parameters of the ligand and its Co(II), Ni(II), Cu(II) and Zn(II) complexes have been calculated. Protonation constants of Schiff base and stability constants of their binary metal complexes have been determined potentiometrically in 50% DMSO-water media at 25 °C and ionic strength 0.10 M sodium perchlorate.

  4. 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

    2015-04-01

    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

  5. Synthesis, characterization, DNA binding, DNA cleavage and antimicrobial studies of schiff base ligand and its metal complexes.

    PubMed

    Mendu, Padmaja; Kumari, C Gyana; Ragi, Rajesh

    2015-03-01

    A series of Cu(II) , Ni(II) , Co(II) , Mn(II) and Zn(II) complexes have been synthesized from the Schiff base ligand L. The Schiff base ligand 4-chloro-2-((4-oxo-4H-chromen-3yl) methylene amino) benzoic acid (L) has been synthesized by the reaction between chromone-3-carbaldehyde and 4-chloro-2-amino benzoic acid. The nature of bonding and geometry of the transition metal complexes as well as ligand L have been deduced from elemental analysis, FT-IR, UV-vis, (1)H NMR, (13)C NMR, ESR spectral studies, mass, magnetic susceptibility and molar conductance measurements. The complexes are found to have ML2 composition and are neutral in DMSO. Based on elemental, conductance and spectral studies, six-coordinated geometry was assigned for these complexes. The ligand L acts as tridentate and coordinates through nitrogen atom of azomethine group, hydroxyl of the carboxyl group and oxygen atom of keto group of ?-pyrone ring. The interaction of Cu(II) complex with CT- DNA was carried out by UV-vis, fluorescence titrations and viscosity measurements. The complex binds to DNA through intercalative binding mode. The nuclease activity of the above metal complexes shows that Cu(II) and Co(II) complexes cleave DNA through redox chemistry. The biological activity of the ligand and its complexes have been studied on four bacteria E.coli, B.subtilis, pseudomonas and Edwardella and two fungi penicillium and trichoderma by well disc and fusion method and found that the metal complexes are more active than the free Schiff base ligand. PMID:25663196

  6. Assembling of Complex Heterocyclic Ensembles, Schiff Bases, from 5Amino3-[2-(4,5,6,7-tetrahydroindolyl)]pyrazoles and 1Vinyl(ethyl)-2-formylimidazoles

    Microsoft Academic Search

    L. V. Baikalova; L. N. Sobenina; A. I. Mikhaleva; I. A. Zyryanova; N. N. Chipanina; A. V. Afonin; B. A. Trofimov

    2001-01-01

    Condensation of 5-amino-3-(2-pyrrolyl)pyrazoles with 1-vinyl(ethyl)-2-formylimidazoles afforded complex heterocyclic ensembles: Schiff bases containing pyrrole, pyrazole, and imidazole rings. The cis,trans-orientation of CH = N and CH2 = CH groups and E-isomeric structure of the Schiff bases under study with respect to the imine fragment, and also the presence of intra- and intermolecular hydrogen bonds were established.

  7. Synthesis, Structural Characterization and Electrochemical studies of complexes from the NO ligating Schiff bases of furoic acid hydrazide

    Microsoft Academic Search

    S. M. Rahuma; S. O. Sharifah Rohaiza; M. A. Hapipah; B. Wan Jefrey

    Nine new cobalt(II) and manganese(II) complexes with Schiff base derived from the condensation of 2-hydroxyacetophenone (L1), 5-chloro-2-hydroxyacetophenone (L2) , thiophene-2-carboxaldehyde (L3) and 3-methylthiophene-2-carboxaldehyde (L4) with furoic acid hydrazide have been prepared. Another two cobalt complexes with Shiff bases obtained from 2-hydroxyacetophenone (L5), 5-chloro-2-hydroxyacetophenone (L6) with 2- hydroxy-2-naphtholichydrazide were also synthesized .All the complexes were characterized by means of FTIR, FT

  8. 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

  9. Immobilization of cobalt(III) Schiff base complexes onto Montmorillonite-K10: Synthesis, experimental and theoretical structural determination

    NASA Astrophysics Data System (ADS)

    Kianfar, Ali Hossein; Kamil Mahmood, Wan Ahmad; Dinari, Mohammad; Farrokhpour, Hossein; Enteshari, Majid; Azarian, Mohammad Hossein

    2015-02-01

    The [Co(naphophen)(PPh3)(OH2)]ClO4 and [Co(naphophen)(PBu3)(OH2)]BF4 (where naphophen = bis(naphthaldehyde)1,2-phenylenediimine) complexes were synthesized and chracterized by FT-IR, UV-Vis, 1H NMR, 13C NMR spectroscopy and elemental analysis techniques. The coordination geometry of the synthesized complexes were determined by X-ray crystallography. Cobalt (III) complexes have six-coordinated pseudo-octahedral geometry in which the O(1), O(2), N(1) and N(2) atoms of the Schiff base forms the equatorial plane. These complexes showed a dimeric structure via hydrogen bonding between the phenolate oxygen and the hydrogens of the coordinated H2O molecule. The theoretical calculations were also performed to optimize the structure of the complexes in the gas phase to confirm the structures proposed by X-ray crystallography. In addition, UV-Visible and IR spectra of complexes were calculated and compared with the corresponding experimental spectra to complete the experimental structural identification. The synthesized complexes were incorporated onto the Montmorillonite-K10 nanoclay via simple ion-exchange reaction. The structure and morphology of the obtained nanohybrids were identified by FT-IR, XRD, TGA/DTA, SEM and TEM techniques. Based on the XRD results of the new nanohybrid materials, the Schiff base complexes were intercalated in the interlayer spaces of clay. SEM and TEM micrographs of the clay/complex shows that the resulting hybrid nanomaterials has layer structures.

  10. 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.

  11. Synthesis, physicochemical studies, embryos toxicity and DNA interaction of some new Iron(II) Schiff base amino acid complexes

    NASA Astrophysics Data System (ADS)

    Abdel-Rahman, Laila H.; El-Khatib, Rafat M.; Nassr, Lobna A. E.; Abu-Dief, Ahmed M.

    2013-05-01

    New Fe(II) Schiff base amino acid complexes derived from the condensation of o-hydroxynaphthaldehyde with L-alanine, L-phenylalanine, L-aspartic acid, L-histidine and L-arginine were synthesized and characterized by elemental analysis, IR, electronic spectra, and conductance measurements. The stoichiometry and the stability constants of the complexes were determined spectrophotometrically. The investigated Schiff bases exhibited tridentate coordination mode with the general formulae [Fe(HL)2]·nH2O for all amino acids except L-histidine. But in case of L-histidine, the ligand acts as tetradentate ([FeL(H2O)2]·2H2O), where HL = mono anion and L = dianion of the ligand. The structure of the prepared complexes is suggested to be octahedral. The prepared complexes were tested for their toxicity on chick embryos and found to be safe until a concentration of 100 ?g/egg with full embryos formation. The interaction between CT-DNA and the investigated complexes were followed by spectrophotometry and viscosity measurements. It was found that, the prepared complexes bind to DNA via classical intercalative mode and showed a different DNA cleavage activity with the sequence: nhi > nari > nali > nasi > nphali. The thermodynamic Profile of the binding of nphali complex and CT-DNA was constructed by analyzing the experimental data of absorption titration and UV melting studies with the McGhee equation, van't Hoff's equation, and the Gibbs-Helmholtz equation.

  12. 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.

  13. 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.

  14. Synthesis, crystal structures and magnetic properties of dinuclear copper(II) compounds with NNO tridentate Schiff base ligands and bridging aliphatic diamine and aromatic diimine linkers.

    PubMed

    Rigamonti, Luca; Forni, Alessandra; Pievo, Roberta; Reedijk, Jan; Pasini, Alessandro

    2011-04-01

    The synthesis and the characterization of new dinuclear copper(II) compounds of general formula [(L(a-d))(2)Cu(2)(?-N-N)](ClO(4))(2) (1-6) with either neutral aliphatic diamine (N-N = piperazine, pip) or aromatic diimine (N-N = 4,4'-bipyridine, 4,4'-bipy) linker are reported. The copper ligands L(-) (L(a-) = (E)-2-((2-aminoethylimino)methyl)phenolate, L(b-) = (E)-2-((2-aminopropylimino)methyl)-phenolate, L(c-) = (E)-2-((2-aminoethylimino)methyl)4-nitrophenolate, L(d-) = (E)-2-((2-aminoethylimino)methyl)4-methoxyphenolate) are NNO tridentate Schiff bases derived from the monocondensation of a substituted salicylaldehyde 5-G-salH (G = NO(2), H, OMe) with ethylenediamine, en, or 1,3-propylenediamine, tn. The crystal structures of compounds [(L(a))(2)Cu(2)(MeOH)(2)(?-4,4'-bipy)](ClO(4))(2) (1·2MeOH), [(L(b))(2)Cu(2)(MeOH)(2)(?-4,4'-bipy)](ClO(4))(2) (2·2MeOH), [(L(d))(2)Cu(2)(?-4,4'-bipy)](ClO(4))(2) (4), [(L(a))(2)Cu(2)(?-pip)](ClO(4))(2) (5) and [(L(b))(2)Cu(2)(?-pip)](ClO(4))(2) (6) have been determined, revealing the preferred (e-e)-chair conformation of the bridging piperazine in compounds 5 and 6. The presence of hydrogen-bond-mediated intermolecular interactions, that involve the methanol molecules, yields dimers of dinuclear units for 1·2MeOH, and infinite zig-zag chains for 2·2MeOH. The temperature dependences of the magnetic susceptibilities ?(M)(T) for all compounds were measured, indicating the presence of antiferromagnetic Cu-Cu exchange. For the compounds 2-4 with 4,4'-bipy, the coupling constants J are around -1 cm(-1), while in compound 1 no interaction could be detected. The compounds 5 and 6 with piperazine display higher Cu-Cu magnetic interactions through the ?-bonding backbone of the bridging molecule, with J around -8 cm(-1), and the coupling is favoured by the (e-e)-chair conformation of the diamine ring. The non-aromatic, but shorter, linker piperazine gives rise to stronger Cu-Cu antiferromagnetic couplings than the aromatic, but longer, 4,4'-bipyridine. In the latter case, the rotation along the C-C bond between the two pyridyl rings and the consequent non co-planarity of the two copper coordination planes play an important role in determining the magnetic communication. EPR studies reveal that the dinuclear species are not stable in solution, yielding the solvated [(L)Cu(MeOH)](+) and the mononuclear [(L)Cu(N-N)](+) species; it appears that the limited solubility of the dinuclear compounds is responsible for their isolation in the solid state. PMID:21340057

  15. Synthesis, structural, thermal studies and biological activity of a tridentate Schiff base ligand and their transition metal complexes

    NASA Astrophysics Data System (ADS)

    Abd El-halim, Hanan F.; Omar, M. M.; Mohamed, Gehad G.

    2011-01-01

    Schiff base (L) ligand is prepared via condensation of pyridine-2,6-dicarboxaldehyde with -2-aminopyridine. The ligand and its metal complexes are characterized based on elemental analysis, mass, IR, solid reflectance, magnetic moment, molar conductance, and thermal analyses (TG, DTG and DTA). The molar conductance reveals that all the metal chelates are non-electrolytes. IR spectra shows that L ligand behaves as neutral tridentate ligand and bind to the metal ions via the two azomethine N and pyridine N. 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), Ni(II), Cu(II), and Th(IV)) and tetrahedral (Mn(II), Cd(II), Zn(II), and UO 2(II)). The thermal behaviour of these chelates shows that the hydrated complexes losses water molecules of hydration in the first step followed immediately by decomposition of the anions and ligand molecules in the subsequent steps. The activation thermodynamic parameters, such as, E*, ? H*, ? S* and ? G* are calculated from the DTG curves using Coats-Redfern method. The synthesized ligand, in comparison to their metal complexes also was screened for its antibacterial activity against bacterial species, Escherichia coli, Pseudomonas aeruginosa, Staphylococcus pyogones and Fungi ( Candida). The activity data shows that the metal complexes to be more potent/antibacterial than the parent Schiff base ligand against one or more bacterial species.

  16. 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.

  17. Modern spectroscopic technique in the characterization of biosensitive macrocyclic Schiff base ligand and its complexes: Inhibitory activity against plantpathogenic fungi

    NASA Astrophysics Data System (ADS)

    Tyagi, Monika; Chandra, Sulekh; Akhtar, Jameel; Chand, Dinesh

    2014-01-01

    Complexes of the type [M(L)Cl2], where M = Co(II), Ni(II) and Cu(II) have been synthesized with a macrocyclic Schiff base ligand (1,4,5,7,10,11,12,15-octaaza,5,11,16,18-tetraphenyl, 3,4,12,13-tetramethyl cyclo-octadecane) derived from Schiff base (obtained by the condensation of 4-aminoantipyrine and dibenzoyl methane) and ethylenediamine. The ligand was characterized on the basis of elemental analysis, IR, 1H NMR, EI Mass and molecular modeling studies while the complexes were characterized by elemental analysis, molar conductance measurements, magnetic susceptibility measurements, IR, electronic and EPR spectral studies. All the complexes are non-electrolyte in nature. The covalency factor (?) and coefficient factor (?) suggest the covalent nature of the complexes. The ligand and its metal complexes have shown antifungal activity with their LD50 values determined by probit analysis against two economically important fungal plant pathogens i.e. Macrophomina phaseolina and Fusarium solani.

  18. Modern spectroscopic technique in the characterization of biosensitive macrocyclic Schiff base ligand and its complexes: inhibitory activity against plantpathogenic fungi.

    PubMed

    Tyagi, Monika; Chandra, Sulekh; Akhtar, Jameel; Chand, Dinesh

    2014-01-24

    Complexes of the type [M(L)Cl2], where M = Co(II), Ni(II) and Cu(II) have been synthesized with a macrocyclic Schiff base ligand (1,4,5,7,10,11,12,15-octaaza,5,11,16,18-tetraphenyl, 3,4,12,13-tetramethyl cyclo-octadecane) derived from Schiff base (obtained by the condensation of 4-aminoantipyrine and dibenzoyl methane) and ethylenediamine. The ligand was characterized on the basis of elemental analysis, IR, (1)H NMR, EI Mass and molecular modeling studies while the complexes were characterized by elemental analysis, molar conductance measurements, magnetic susceptibility measurements, IR, electronic and EPR spectral studies. All the complexes are non-electrolyte in nature. The covalency factor (?) and coefficient factor (?) suggest the covalent nature of the complexes. The ligand and its metal complexes have shown antifungal activity with their LD50 values determined by probit analysis against two economically important fungal plant pathogens i.e. Macrophomina phaseolina and Fusarium solani. PMID:24161868

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

    PubMed

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

    2014-10-15

    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, (1)H NMR, (13)C 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, (1)H NMR, (13)C 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. PMID:24820326

  20. Synthesis and characterization of Ni(II) complexes of O,N-donor Schiff bases derived from acyl pyrazolone analogues

    Microsoft Academic Search

    Komal M. Vyas; Vrunda K. Shah; R. N. Jadeja

    2011-01-01

    Two bidentate Schiff bases, 5-methyl-2-p-tolyl-4-(1-p-tolylimino-propyl)-2H-pyrazol-3-ol (L1) and 2-(3-chloro-phenyl)-5-methyl-4-(1-p-tolylimino-propyl)-2H-pyrazol-3-ol (L2), were synthesized by condensation of 4-acyl pyrazolones with p-toluidine in ethanol. These ligands have been characterized by elemental analysis, infrared (IR), H NMR, and mass spectra. A single crystal molecular structure of ligand L2 was also solved. Nickel(II) complexes of these ligands with general formula [ML2?·?2H2O] have been prepared by the

  1. Synthesis and crystal structure of Schiff base transition metal complex [Co(PMBP-smdtc) 2 ]?2H 2 O

    Microsoft Academic Search

    Yali Ji; Lang Liu; Dianzeng Jia; YongMin Qiao; Kaibei Yu

    2002-01-01

    A cobalt(II) complex, [Co(PMBP-smdtc)2]·2H2O, in which PMBP-smdtc is the l-phenyl-3-methyl-4-benzoyl-5-pyrazolone Schiff base of S-methyldithiocarbazate, has been synthesized and characterized by IR spectrum and single crystal X-ray diffraction. The crystal is monoclinic: space group C2\\/c, with a = 12.455(2) Å, b = 16.024(2) Å, c = 20.513(3) Å, ß = 101.18(1)°, V = 4016.3(10) Å3, and Z = 4. The cobalt

  2. Synthesis and characterization of inclusion complexes of aliphatic-aromatic poly(Schiff base)s with ?-cyclodextrin (highlight)

    Microsoft Academic Search

    Zhang Youming; Deng Xinrong; Wang Liangcheng; Wei Taibao

    2008-01-01

    This paper describes the formation of polymer inclusion complexes(polymer-CD-ICs) between ?-cyclodextrin(?-CD) and aliphatic-aromatic\\u000a poly(Schiff base)s. Fourier transform infrared(FTIR) spectroscopy, 1H nuclear magnetic resonance spectroscopy(1H-NMR), thermogravimetric analysis(TGA) and X-ray diffraction(XRD) have been used to observe the formation of polymer-CD-ICs.\\u000a In FTIR spectra, the characteristic peaks of ?-CD at 3391 cm?1 shifted to 3418 cm?1 and the intense peak at 1602 cm?1 due to the

  3. 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

    Microsoft Academic Search

    N. Raman; A. Selvan; P. Manisankar

    2010-01-01

    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 [ML2] (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,

  4. Synthesis, characterization and structural determination of some nickel(II) complexes containing imido Schiff bases and substituted phosphine ligands

    NASA Astrophysics Data System (ADS)

    Kianfar, Ali Hossein; Ebrahimi, Mostafa

    2013-11-01

    Some new tridentate ONN Schiff base complexes of [NiL(PR3)] (where L = Salicylidene2-amino4-nitrobenzene (L1), 5-BrSalicylidene2-amino4-nitrobenzene (L2), 5-NO2Salicylidene2-amino4-nitrobenzene (L3), 5-MeOSalicylidene2-amino4-nitrobenzene (L4) and 3-MeOSalicylidene2-amino4-nitrobenzene (L5), R = Bu and Ph (with L1)) were synthesised and characterized by IR, UV-Vis, 1H NMR spectroscopy and elemental analysis. The geometry of [NiL1(PPh3)] was determined by X-ray crystallography. It indicated that the complex had a planar structure and four coordinates in the solid state. The thermogravimetry (TG) and differential thermoanalysis (DTA) of the synthesized complexes were carried out in the range of 20-600 °C, leading to the decomposition of L1-L3 type in three stages and of L4-L5 and [NiL1(PPh3)] type in four stages. Thermal decomposition of the complexes was closely the dependent upon the nature of the Schiff base ligands and proceeded via the first order kinetics.

  5. Synthesis, characterization and structural determination of some nickel(II) complexes containing imido Schiff bases and substituted phosphine ligands.

    PubMed

    Kianfar, Ali Hossein; Ebrahimi, Mostafa

    2013-11-01

    Some new tridentate ONN Schiff base complexes of [NiL(PR3)] (where L=Salicylidene2-amino4-nitrobenzene (L(1)), 5-BrSalicylidene2-amino4-nitrobenzene (L(2)), 5-NO2Salicylidene2-amino4-nitrobenzene (L(3)), 5-MeOSalicylidene2-amino4-nitrobenzene (L(4)) and 3-MeOSalicylidene2-amino4-nitrobenzene (L(5)), R=Bu and Ph (with L(1))) were synthesised and characterized by IR, UV-Vis, (1)H NMR spectroscopy and elemental analysis. The geometry of [NiL(1)(PPh3)] was determined by X-ray crystallography. It indicated that the complex had a planar structure and four coordinates in the solid state. The thermogravimetry (TG) and differential thermoanalysis (DTA) of the synthesized complexes were carried out in the range of 20-600°C, leading to the decomposition of L(1)-L(3) type in three stages and of L(4)-L(5) and [NiL(1)(PPh3)] type in four stages. Thermal decomposition of the complexes was closely the dependent upon the nature of the Schiff base ligands and proceeded via the first order kinetics. PMID:23892113

  6. 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.

  7. Synthesis, spectral, electrochemical and catalytic properties of Ru(III) Schiff base complexes containing N, O donors

    NASA Astrophysics Data System (ADS)

    Raja, K. Kanmani; Indra Gandhi, N.; Lekha, L.; Easwaramoorthy, D.; Rajagopal, G.

    2014-02-01

    A series of new hexa coordinated ruthenium(III) complexes of the type [RuY2(EPh3)2(X-DPMP)] (where Y = Br or Cl; E = P or As; DPMP = 2-[(2,6-Diisopropyl-phenylimino)-methyl]-phenol, X = H, Br, Cl, I and Ph) have been synthesized by equimolar [RuY3(EPh3)3] and the Schiff base ligands in benzene. The bidentate Schiff base ligands (X-DPMP) have been derived from condensation of 2,6-diisopropylaniline with mono and multisubstituted salicylaldehyde derivatives. The complexes have been characterized by elemental analysis, magnetic susceptibility, UV-Vis., IR and EPR spectral and electrochemical measurements. All the ruthenium(III) complexes are found to be stable, paramagnetic, low spin, redox active and display either quasi reversible or irreversible redox couples based on metal centre. They have exhibited catalytic activity for the oxidation of wide range of primary and secondary alcohols to corresponding aldehydes or ketones with moderate to high conversion in the presence of N-methylmorpholine-N-oxide (NMO) as co-oxidant.

  8. 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.

  9. Fast O2 Binding at Dicopper Complexes Containing Schiff-Base Dinucleating Ligands

    PubMed Central

    Company, Anna; Gómez, Laura; Mas-Ballesté, Rubén; Korendovych, Ivan V.; Ribas, Xavi; Poater, Albert; Parella, Teodor; Fontrodona, Xavier; Benet-Buchholz, Jordi; Solà, Miquel; Que, Lawrence; Rybak-Akimova, Elena; Costas, Miquel

    2008-01-01

    A new family of dicopper(I) complexes [CuI2RL](X)2, (R = H, 1X, R = tBu, 2X and R = NO2, 3X, X = CF3SO3, ClO4, SbF6 or BArF, BArF = [B{3,5-(CF3)2-C6H3}4]?), where RL is a Schiff-base ligand containing two tridentate binding sites linked by a xylyl spacer have been prepared, characterized, and their reaction with O2 studied. The complexes were designed with the aim of reproducing structural aspects of the active site of type 3 dicopper proteins; they contain two three-coordinate copper sites and a rather flexible podand ligand backbone. The solid state structures of 1ClO4, 2CF3SO3, 2ClO4 and 3BArF·CH3CN have been established by single crystal X-ray diffraction analysis. 1ClO4 adopts a polymeric structure in solution while 2CF3SO3, 2ClO4 and 3BArF·CH3CN are monomeric. The complexes have been studied in solution by means of 1H and 19F NMR spectroscopy, which put forward the presence of dynamic processes in solution. 1-3BArF and 1-3CF3SO3 in acetone react rapidly with O2 to generate metaestable [CuIII2(?-O)2(RL)]2+ 1-3(O2) and [CuIII2(?-O)2(CF3SO3)(RL)]+ 1-3(O2)(CF3SO3) species, respectively that have been characterized by UV-vis spectroscopy and resonance Raman analysis. Instead, reaction of 1-3BArF with O2 in CH2Cl2 results in intermolecular O2 binding. DFT methods have been used to study the chemical identities and structural parameters of the O2 adducts, and the relative stability of the CuIII2(?-O)2 form with respect to the CuII2(?-?2: ?2-peroxo) isomer. The reaction of 1X, X = CF3SO3 and BArF with O2 in acetone has been studied by stopped-flow exhibiting an unexpected very fast reaction rate (k = 3.82(4) × 103 M?1s?1, ?H‡ = 4.9 ± 0.5 kJ·mol?1, ?S‡ = ?148 ± 5 J·K?1·mol?1), nearly three orders of magnitude faster than in the parent [CuI2(m-XYLMeAN)]2+. Thermal decomposition of 1-3(O2) does not result in aromatic hydroxylation. The mechanism and kinetics of O2 binding to 1X (X = CF3SO3 and BArF) is discussed and compared with those associated to selected examples of reported models of O2-processing copper proteins. A synergistic role of the copper ions in O2 binding and activation is clearly established from this analysis. PMID:17500512

  10. Complexes of Copper(II) with 2,3?Dimethyl?4?formyl(benzhydrazide)?1?phenyl?3?pyrazolin?5?one

    Microsoft Academic Search

    K. C. Raju; P. K. Radhakrishnan

    2003-01-01

    Copper(II) complexes of the Schiff base 2,3?dimethyl?4?formyl?(benzhydrazide)?1?phenyl?3?pyrazolin?5?one (L) of the general formula [Cu(L)2]X2 (X = ClO4 or NO3), [Cu(L)Cl2] and [Cu(L)2Br2] have been synthesized and characterized by elemental analyses, electrical conductance in non?aqueous solvents, infrared, electronic and EPR spectra, as well as magnetic susceptibility measurements. In these complexes, the ligand acts as a neutral bidentate unit coordinating through the azomethine nitrogen atom

  11. Synthesis, spectral characterization, and biological evaluation of transition metal complexes of bidentate N, o donor schiff bases.

    PubMed

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

    2014-01-01

    New series of three bidentate N, O donor type Schiff bases (L (1) )-(L (3) ) 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

  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. Cobalt, nickel, copper and zinc complexes with 1,3-diphenyl-1H-pyrazole-4-carboxaldehyde Schiff bases: antimicrobial, spectroscopic, thermal and fluorescence studies.

    PubMed

    Singh, Kiran; Kumar, Yogender; Puri, Parvesh; Kumar, Mahender; Sharma, Chetan

    2012-06-01

    Two new Schiff bases of 1,3-diphenyl-1H-pyrazole-4-carboxaldehyde and 4-amino-5-mercapto-3-methyl/H-1,2,4-triazole [HL(1-2)] and their Cobalt, Nickel, Copper and Zinc complexes have been synthesized and characterized by elemental analyses, spectral (UV-vis, IR, (1)H NMR, Fluorescence) studies, thermal techniques and magnetic measurements. A square planar geometry for Cu(II) and octahedral geometry for Co(II), Ni(II) and Zn(II) complexes have been proposed. In order to evaluate the biological activity of Schiff bases and to assess the role of metal ion on biological activity, the pyrazole Schiff bases and their metal complexes have been studied in vitro antibacterial against Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Pseudomonas aeruginosa and antifungal against Aspergillus niger, and Aspergillus flavus. In most of the cases higher activity was exhibited upon coordination with metal ions. PMID:22429912

  14. Homo dinuclear lanthanide(III) complexes of a mesogenic Schiff-base, N, N'-di-(4-decyloxysalicylidene)-1',6'-diaminohexane: Synthesis and characterization

    NASA Astrophysics Data System (ADS)

    Shakya, Pawan Raj; Singh, Angad Kumar; Rao, T. R.

    2011-09-01

    A mesogenic Schiff-base, N, N'-di-(4-decyloxysalicylidene)-1',6'-diaminohexane, H 2ddsdh (abbreviated as H 2L 2) that exhibits smectic-B ( SmB) mesophase, was synthesized and its structure studied by elemental analysis, mass spectrometry, NMR & IR spectral techniques. The Schiff-base, H 2L 2, upon condensation with hydrated lanthanide(III) nitrates, yields Ln III complexes of the general composition [Ln 2(L 2H 2) 3(NO 3) 4](NO 3) 2, where Ln = La, Pr, Nd, Sm, Eu, Gd, Tb, Dy and Ho. IR and NMR spectral data imply a bi-dentate bonding of the Schiff-base in its zwitterionic form (as L 2H 2) to the Ln III ions through two phenolate oxygens. The POM and DSC studies reveal that none of the Ln III complexes exhibits mesomorphism. Fluorescence studies show that the Tb III complex displays characteristic metal-centered fluorescence (solution state).

  15. Spectral characterization, cyclic voltammetry, morphology, biological activities and DNA cleaving studies of amino acid Schiff base metal(II) complexes

    NASA Astrophysics Data System (ADS)

    Neelakantan, M. A.; Rusalraj, F.; Dharmaraja, J.; Johnsonraja, S.; Jeyakumar, T.; Sankaranarayana Pillai, M.

    2008-12-01

    Metal complexes are synthesized with Schiff bases derived from o-phthalaldehyde (opa) and amino acids viz., glycine (gly) L-alanine (ala), L-phenylalanine (pal). Metal ions coordinate in a tetradentate or hexadentate manner with these N 2O 2 donor ligands, which are characterized by elemental analysis, molar conductance, magnetic moments, IR, electronic, 1H NMR and EPR spectral studies. The elemental analysis suggests the stoichiometry to be 1:1 (metal:ligand). Based on EPR studies, spin-Hamiltonian and bonding parameters have been calculated. The g-values calculated for copper complexes at 300 K and in frozen DMSO (77 K) indicate the presence of the unpaired electron in the d orbital. The evaluated metal-ligand bonding parameters showed strong in-plane ?- and ?-bonding. X-ray diffraction (XRD) and scanning electron micrography (SEM) analysis provide the crystalline nature and the morphology of the metal complexes. The cyclic voltammograms of the Cu(II)/Mn(II)/VO(II) complexes investigated in DMSO solution exhibit metal centered electroactivity in the potential range -1.5 to +1.5 V. The electrochemical data obtained for Cu(II) complexes explains the change of structural arrangement of the ligand around Cu(II) ions. The biological activity of the complexes has been tested on eight bacteria and three fungi. Cu(II) and Ni(II) complexes show an increased activity in comparison to the controls. The metal complexes of opapal Schiff base were evaluated for their DNA cleaving activities with calf-thymus DNA (CT DNA) under aerobic conditions. Cu(II) and VO(II) complexes show more pronounced activity in presence of the oxidant.

  16. Synthesis, Characterization and Crystal Structure Studies of Nickel(II) Complexes With NO Donor Schiff Base Ligands.

    PubMed

    Vafazadeh, Rasoul; Gorji, Alireza; Ansari, Sara; Willis, Anthony C

    2012-12-01

    Four complexes of the type [Ni(N-substituted-salicydenaminato)2], with bidentate Schiff base ligands (L1-L4), have been synthesized. The complexes were characterized by IR and elemental analysis methods. The solid state structures of three complexes (1-3) were determined by X-ray crystallography. The complexes show mononuclear, four-coordinate, slightly distorted square-planar trans-Ni(N2O2) geometry. The angles around the Ni center deviate slightly from 90° indicating a rectangular distortion. The chelating N-Ni-O angles are larger than 90° whereas the non-chelating N-Ni-O angles are smaller than 90°. The crystallograpic studies indicate that any steric/electronic effects due to CH3 and Br moieties have had no significant impact on the coordination sphere. PMID:24061373

  17. 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.

  18. Two tridentate Schiff base ligands and their mononuclear cobalt (III) complexes: Synthesis, characterization, antibacterial and antifungal activities

    NASA Astrophysics Data System (ADS)

    Gungor, Elif; Celen, Selma; Azaz, Dilek; Kara, Hulya

    Two Schiff base ligands (HL1, HL2) and their Co(III) complexes, [Co(HL1)(L1)] (1) and [Co(HL2)(L2)] (2) [where HL1 = 2-((E)-(2-hydroxyethylimino)methyl)-4-chlorophenol and HL2 = 2-((E)-(2-hydroxyethylimino)methyl)-4-bromophenol] were synthesized and characterized using spectroscopic methods. The crystal structures of 1 and 2 have been re-determined by single crystal diffraction at 100 K. The ligands and their Co(III) complexes were screened for antibacterial and antifungal activities by the disc diffusion, microdilution broth and single spore culture techniques. The antimicrobial activity of the Co(III) complexes and the free ligands exhibit antimicrobial properties and the Co(III) complexes show enhanced inhibitory activity compared with their parent ligand.

  19. 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.

    PubMed

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

    2012-08-01

    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 (1)H 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 R(2)SnCl(2) (R=methyl, phenyl, n-butyl), PhSnCl(3) and Bu(3)SnCl 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=283-313K) 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 R(n)SnCl(4-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. PMID:22626922

  20. Metal complexes of a novel Schiff base derived from sulphametrole and varelaldehyde. Synthesis, spectral, thermal characterization and biological activity

    NASA Astrophysics Data System (ADS)

    Mohamed, Gehad G.; Zayed, M. A.; Abdallah, S. M.

    2010-08-01

    Metal complexes of a novel Schiff base (HL = 3-(4'-ethylazomethinobenzene sulphonamide)-4-methoxy-1,2,5-thiadiazole) derived from condensation of sulphametrole and varelaldehyde are reported and characterized based on elemental analyses, IR, solid reflectance, magnetic moment, molar conductance, and thermal analysis (TG). From the elemental analyses data, 1:1 metal complexes are formed having the general formulae [MCl 3(HL)(H 2O)]·3H 2O (M = Cr(III), Fe(III)) and [MCl 2(HL)(H 2O) 2]· yH 2O (where M = Mn(II), Fe(II), Co(II), Ni(II), Cu(II) and Zn(II), y = 0-3). The important infrared (IR) spectral bands corresponding to the active groups in the ligand and the solid complexes under investigation were studied. IR spectra show that HL is coordinated to the metal ions in a neutral bidentate manner with ON donor sites of the enolic sulphonamide- OH and thiodiaza- N. The solid complexes have been synthesized and studied by thermogravimetric analysis. The thermal dehydration and decomposition of these complexes were studied kinetically using the integral method applying the Coats-Redfern equation. All the metal chelates are found to be non-electrolytes. From the magnetic and solid reflectance spectra, the complexes have octahedral structures. The antibacterial and antifungal activities of the synthesized ligand and its metal complexes were screened against bacterial species ( Escherichia coli and Staphylococcus aureus) and fungi ( Candida and Aspergillus flavus). 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.

  1. 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.

  2. Vo(IV), Fe(III), Co(II) and Cd(II) Complexes of Asymmetric Schiff Base Ligands (N2O3). Synthesis and Spectroscopic Studies

    Microsoft Academic Search

    Saied M. E. Khalil; Hoda F. O. El-Shafiy

    2000-01-01

    New series of mononuclear VO(IV), Co(II) and Cd(II) complexes of the formula [HLVO(OH2)]·nH2O, [HLCo]·xH2O and [HLCd]·xH2O and binuclear Fc(III) complexes of the formula [LFe2Cl2(H2O)3]Cl·H2O have been synthesized. L stands for one of the five asymmetrical pentadentate (N2O3) Schiff base ligands H3L-H3L prepared by the condensation of acetoacetylphenol and ethylenediamine in the molar ratio 1:1 to prepare a half-unit Schiff base

  3. Synthesis and characterization of diorganotin(IV) complexes of tetradentate Schiff bases: crystal structure of n-Bu 2Sn(Vanophen)

    Microsoft Academic Search

    Dilip Kumar Dey; Manas Kumar Saha; Mrinal Kanti Das; Neetu Bhartiya; R. K. Bansal; Georgina Rosair; Samiran Mitra

    1999-01-01

    Diorganotin(IV) complexes of the general formula R2SnL (R=Ph, n-Bu and Me) have been prepared from diorganotin(IV) dichlorides (R2SnCl2) and tetradentate Schiff bases (H2L) containing N2O2 donor atoms in the presence of triethylamine in benzene. The Schiff bases, H2L, were derived from salicylaldehyde, 3-methoxysalicylaldehyde (o-vanillin), 1-phenyl-3-methyl-4-benzoyl-5-pyrazolone and diamines such as o-phenylenediamine and 1,3-propylenediamine. The complexes were characterized by IR, NMR (1H,

  4. Structural investigation of oxovanadium(IV) Schiff base complexes: X-ray crystallography, electrochemistry and kinetic of thermal decomposition.

    PubMed

    Asadi, Mozaffar; Asadi, Zahra; Savaripoor, Nooshin; Dusek, Michal; Eigner, Vaclav; Shorkaei, Mohammad Ranjkesh; Sedaghat, Moslem

    2015-02-01

    A series of new VO(IV) complexes of tetradentate N2O2 Schiff base ligands (L(1)-L(4)), were synthesized and characterized by FT-IR, UV-vis and elemental analysis. The structure of the complex VOL(1)?DMF was also investigated by X-ray crystallography which revealed a vanadyl center with distorted octahedral coordination where the 2-aza and 2-oxo coordinating sites of the ligand were perpendicular to the "-yl" oxygen. The electrochemical properties of the vanadyl complexes were investigated by cyclic voltammetry. A good correlation was observed between the oxidation potentials and the electron withdrawing character of the substituents on the Schiff base ligands, showing the following trend: MeOcomplexes and kinetic aspects of their thermal decomposition. The formation constants with various substituents on the aldehyde ring follow the trend 5-OMe>5-H>5-Br>5-Cl. Furthermore, the kinetic parameters of thermal decomposition were calculated by using the Coats-Redfern equation. According to the Coats-Redfern plots the kinetics of thermal decomposition of studied complexes is of the first-order in all stages, the free energy of activation for each following stage is larger than the previous one and the complexes have good thermal stability. The preparation of VOL(1)?DMF yielded also another compound, one kind of vanadium oxide [VO]X, with different habitus of crystals, (platelet instead of prisma) and without L(1) ligand, consisting of a V10O28 cage, diaminium moiety and dimethylamonium as a counter ions. Because its crystal structure was also new, we reported it along with the targeted complex. PMID:25448962

  5. Structural investigation of oxovanadium(IV) Schiff base complexes: X-ray crystallography, electrochemistry and kinetic of thermal decomposition

    NASA Astrophysics Data System (ADS)

    Asadi, Mozaffar; Asadi, Zahra; Savaripoor, Nooshin; Dusek, Michal; Eigner, Vaclav; Shorkaei, Mohammad Ranjkesh; Sedaghat, Moslem

    2015-02-01

    A series of new VO(IV) complexes of tetradentate N2O2 Schiff base ligands (L1-L4), were synthesized and characterized by FT-IR, UV-vis and elemental analysis. The structure of the complex VOL1?DMF was also investigated by X-ray crystallography which revealed a vanadyl center with distorted octahedral coordination where the 2-aza and 2-oxo coordinating sites of the ligand were perpendicular to the '-yl' oxygen. The electrochemical properties of the vanadyl complexes were investigated by cyclic voltammetry. A good correlation was observed between the oxidation potentials and the electron withdrawing character of the substituents on the Schiff base ligands, showing the following trend: MeO < H < Br < Cl. We also studied the thermodynamics of formation of the complexes and kinetic aspects of their thermal decomposition. The formation constants with various substituents on the aldehyde ring follow the trend 5-OMe > 5-H > 5-Br > 5-Cl. Furthermore, the kinetic parameters of thermal decomposition were calculated by using the Coats-Redfern equation. According to the Coats-Redfern plots the kinetics of thermal decomposition of studied complexes is of the first-order in all stages, the free energy of activation for each following stage is larger than the previous one and the complexes have good thermal stability. The preparation of VOL1?DMF yielded also another compound, one kind of vanadium oxide [VO]X, with different habitus of crystals, (platelet instead of prisma) and without L1 ligand, consisting of a V10O28 cage, diaminium moiety and dimethylamonium as a counter ions. Because its crystal structure was also new, we reported it along with the targeted complex.

  6. Synthesis, spectral characterization, molecular modeling and antimicrobial activity of new potentially N2O2 Schiff base complexes

    NASA Astrophysics Data System (ADS)

    Adly, Omima M. I.; Taha, Ali; Fahmy, Shery A.

    2013-12-01

    Metal complexes of a new potentially tetradentate symmetrical Schiff base ligand (H2L) with Cu(II), Ni(II), Co(II), VO(IV), Zn(II), Cd(II), Ce(III), Fe(III) and UO2(VI) metal ions have been synthesized and characterized based on their elemental analyses, spectral (IR, UV-Vis, 1H NMR and mass spectra), magnetic and molar conductance studies as well as thermal gravimetric analysis (TGA). The synthesized complexes have the general formula [MHxL(H2O)yXn]: x = 0-1, y = 0-4 and n = 0-1; where: L = dianion of 6-hydroxy-5-[N-(2-{[(1E)-1-(6-hydroxy-2,4-dioxo-3,4-dihydro-2H-1,3-thiazin-5-yl)ethylidene]amino}ethyl) ethanimidoyl]-2H-1,3-thiazine-2,4(3H)-dione and X = nitrate or sulphate anion. The ligand behaves as diabasic tetradentate N2O2 sites, except in cases of Co(II), VO(IV) and UO2(VI) metal ions, it behaves as monobasic tetradentate Schiff base ligand. The metal complexes exhibited square planar, square-pyramidal and octahedral geometrical arrangements except for Ce(III) and UO2(VI) complexes, they are octa-coordinated. The Coats-Redfern equation was used to calculate the kinetic and thermodynamic parameters for the different thermal decomposition stages of some complexes. Structural parameters of the ligand and its metal complexes have been theoretically computed on the basis of semiemperical PM3 level, and the results were correlated with their experimental data. The antimicrobial activities of the ligand and its metal complexes were tested against some Gram-positive and Gram-negative bacteria; and fungus strain and the results were discussed.

  7. Synthesis, Characterization, and Kinetic Study of Complexation of Vanadyl Acetylacetone with Some Unsymmetrical N3O Schiff Bases

    Microsoft Academic Search

    Zahra Asadi

    2010-01-01

    This article reports the synthesis and characterization of some new vanadyl Schiff base complexes, ((N-salicylideneN?-pyrrolidene)-1,2-ethylenediaminato)oxovanadium(IV) [VO (Salpyren)], ((7-methyl-N-salicylidene-N?-pyrrolidene)-1,2-ethylenediaminato) oxovanadium(IV) [VO(Mesalpyren)], ((7-phenylN-salicylidene-N?-pyrrolidene)-1,2-ethylenediaminato) oxovanadium(IV) [VO(Phsalpyren)], ((N-salicylidene-N?-pyrrolidene)-1,3propylenediaminato)oxovanadium(IV) [VO(Salpyrpd)], ((7methyl-N-salicylidene-N?-pyrrolidene)-1,3-propylenediaminato) oxovanadium(IV) [VO(Mesalpyrpd)], ((7-phenyl-N-salicylidene-N?-pyrrolidene)-1,3-propylenediaminato)oxovanadium(IV) [VO (Phsalpyrpd)]. These complexes were characterized by elemental analyses, IR, UV-Vis, and mass spectra. The kinetics and mechanism of the complex formation in methanol were studied spectrophotometrically. The second order k2

  8. 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.

  9. Group 12 metal complexes of tetradentate N 2O 2–Schiff-base ligands incorporating pyrazole

    Microsoft Academic Search

    Fabio Marchetti; Claudio Pettinari; Riccardo Pettinari; Augusto Cingolani; Dante Leonesi; Adriana Lorenzotti

    1999-01-01

    New [M(Q)2(X)] derivatives (where M=Zn, Cd or Hg; Q=1-phenyl-3-methyl-4-R(C=O)-pyrazolon-5-ato; in detail: QL, R=C6H5; QB, R=CH2C(CH3)3; QS, R=CH(C6H5)2; X=EtOH or H2O) have been synthesised and characterised. These compounds undergo a condensation reaction with the appropriate diamine in ethanol, affording novel Schiff-base metal derivatives [M(diaquo)bis(1-phenyl-3methyl-4-R(C=N)-pyrazolone)(CH2)ndiimmine] (LnH2, R=C6H5, n=2, 3 or 4; BnH2, R=CH2C(CH3)3, n=2, 3 or 4; SnH2, R=CH(C6H5)2, n=2 or 3;

  10. Binuclear ruthenium(III) Schiff base complexes bearing N 4O 4 donors and their catalytic oxidation of alcohols

    NASA Astrophysics Data System (ADS)

    Venkatachalam, G.; Raja, N.; Pandiarajan, D.; Ramesh, R.

    2008-12-01

    An interesting series of binuclear ruthenium(III) Schiff base complexes bearing bis-salophen/bis-naphophen units of the general composition [(EPh 3)(X)Ru-L-Ru(X)(EPh 3)] (where E = P or As; X = Cl or Br; L = binucleating dianionic tetradentate ligands) have been synthesized and characterized by analytical (elemental analysis, magnetic susceptibility measurements), spectral (FT-IR, UV-vis and EPR) and electrochemical methods. These ruthenium(III) complexes have two N 2O 2 metal binding sites, which are linked to each other with a biphenyl bridge and acts as potential catalyst for oxidation of wide range of primary and secondary alcohols to corresponding aldehydes or ketones with moderate to high conversion in the presence of N-methylmorpholine- N-oxide (NMO). The formation of high-valent Ru V = O species as a catalytic active intermediate is proposed for the catalytic processes.

  11. Amino acetate functionalized Schiff base organotin(IV) complexes as anticancer drugs: synthesis, structural characterization, and in vitro cytotoxicity studies

    Microsoft Academic Search

    Tushar S. Basu Baul; Smita Basu; Dick de Vos; Anthony Linden

    2009-01-01

    Summary  Potassium 2-{[(2Z)-(3-hydroxy-1-methyl-2-butenylidene)]amino}-4-methyl-pentanoate (L1HK) and potassium 2-{[(E)-1-(2-hydroxyphenyl)alkylidene]amino}-4-methyl-pentanoates (L2HK-L3HK) underwent reactions with PhnSnCl4-n (n?=?2 and 3) to give the amino acetate functionalized Schiff base organotin(IV) complexes [Ph3SnLH]\\u000a n\\u000a (1–3) and [Ph2SnL] (4), respectively. These complexes have been characterized by 1H, 13C, 119Sn NMR, IR spectroscopic techniques in combination with elemental analyses. The crystal structures of 1 and 3 were determined.\\u000a The crystal

  12. SYNTHESIS AND CHARACTERISATION OF RUTHENIUM(III) COMPLEXES CONTAINING MONOBASIC BIDENTATE SCHIFF BASES AND THEIR BIOLOGICAL ACTIVITIES

    Microsoft Academic Search

    T. Daniel Thangadurai; M. Gowri; K. Natarajan

    2002-01-01

    New hexa-coordinated ruthenium(III) complexes of the type [RuX2 F(L)(EPh3)2] (X=Cl or Br; L=monobasic bidentate Schiff base ligand; E=P or As) have been synthesised by the reactions of [RuCl3(PPh3)3], [RuCl3(AsPh3)3], [RuBr3-(AsPh3)3] or [RuBr3(PPh3)2(MeOH)] with the appropriate ligands such as anthranilic acid cinnamaldehyde (Hanthcin), anthranilic acid p-tolualdehyde (Hanth-p-tol) and anthranilic acid p-anisaldehyde (Hanth-p-ans). All of these new complexes were characterised using various

  13. Synthesis, characterization, electrochemical and biological studies on some metal(II) Schiff base complexes containing quinoxaline moiety

    NASA Astrophysics Data System (ADS)

    Justin Dhanaraj, Chellaian; Johnson, Jijo

    2014-01-01

    Novel Co(II), Ni(II), Cu(II) and Zn(II) complexes of Schiff base derived from quinoxaline-2,3-(1,4H)-dione and 4-aminoantipyrine (QDAAP) were synthesized. The ligand and its complexes were characterized by elemental analyses, molar conductance, magnetic susceptibility measurements, FTIR, UV-Vis., mass and 1H NMR spectral studies. The X band ESR spectrum of the Cu(II) complex at 300 and 77 K were also recorded. Thermal studies of the ligand and its complexes show the presence of coordinated water in the Ni(II) and Zn(II) complexes. The coordination behavior of QDAAP is also discussed. All the complexes are mono nuclear and tetrahedral geometry was found for Co(II) complex. For the Ni(II) and Zn(II) complexes, octahedral geometry was assigned and for the Cu(II) complex, square planar geometry has been suggested. The grain size of the complexes was estimated using powder XRD. The surface morphology of the compounds was studied using SEM analysis. Electrochemical behavior of the synthesized complexes in DMF at room temperature was investigated by cyclic voltammetry. The in vitro biological screening of QDAAP and its metal complexes were tested against bacterial species Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa. The fungal species include Aspergillus niger, Aspergillus flavus and Candida albicans. The DNA cleavage activity of QDAAP and its complexes were also discussed.

  14. Synthesis, characterization, and thermodynamics of some new unsymmetrical Schiff bases of salicylaldehyde with 3,4-diaminopyridine and their cobalt(III) complexes

    NASA Astrophysics Data System (ADS)

    Asadi, Mozaffar; Torabi, Susan; Mohammadi, Khosro

    2014-03-01

    Some new Schiff bases derived from 3,4-diaminopyridine (3,4-DAP) and their new unsymmetrical Co(III) five coordinate complexes described as [Co(Chel)(L)]ClO4?H2O where (Chel) is the deprotonated form of a series of unsymmetric ligands containing 3,4-diaminopyridine (3,4-DAP) and substituted salicylaldehyde moieties and a new Co(III) six coordinate Co(III) complex, were synthesized and characterized by 1H NMR, IR, UV-Vis, and elemental analysis. For the new synthesized five coordinate complexes, the formation constants of the interaction of the Co(III) Schiff bases with various donors were measured spectrophotometrically. The trend of the formation constants of the five coordinate Co(III) Schiff base complexes toward a given phosphine is as follow: 5-H > 5-Br and the formation constants trend of these donors are as follow: PBu3 > PPh2Me. Furthermore the adduct formation of the five coordinate [Co(3,4-Salpyr)(PBu3)] ClO4?H2O, with aromatic amines shows the following binding trend: Im > 2-MeIm > 2-EtIm > BzIm. The trend of the formation constants of Co(III) Schiff base complexes toward a given donor according to the phosphine axial ligand is as follow: PBu3 > PPh2Me.

  15. Synthesis, characterization, and thermodynamics of some new unsymmetrical Schiff bases of salicylaldehyde with 3,4-diaminopyridine and their cobalt(III) complexes.

    PubMed

    Asadi, Mozaffar; Torabi, Susan; Mohammadi, Khosro

    2014-03-25

    Some new Schiff bases derived from 3,4-diaminopyridine (3,4-DAP) and their new unsymmetrical Co(III) five coordinate complexes described as [Co(Chel)(L)]ClO4?H2O where (Chel) is the deprotonated form of a series of unsymmetric ligands containing 3,4-diaminopyridine (3,4-DAP) and substituted salicylaldehyde moieties and a new Co(III) six coordinate Co(III) complex, were synthesized and characterized by (1)H NMR, IR, UV-Vis, and elemental analysis. For the new synthesized five coordinate complexes, the formation constants of the interaction of the Co(III) Schiff bases with various donors were measured spectrophotometrically. The trend of the formation constants of the five coordinate Co(III) Schiff base complexes toward a given phosphine is as follow: 5-H>5-Br and the formation constants trend of these donors are as follow: PBu3>PPh2Me. Furthermore the adduct formation of the five coordinate [Co(3,4-Salpyr)(PBu3)] ClO4?H2O, with aromatic amines shows the following binding trend: Im>2-MeIm>2-EtIm>BzIm. The trend of the formation constants of Co(III) Schiff base complexes toward a given donor according to the phosphine axial ligand is as follow: PBu3>PPh2Me. PMID:24342295

  16. 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.

  17. Synthesis, spectroscopic, cytotoxic aspects and computational study of N-(pyridine-2-ylmethylene)benzo[d]thiazol-2-amine Schiff base and some of its transition metal complexes

    NASA Astrophysics Data System (ADS)

    Abd El-Aziz, Dina M.; Etaiw, Safaa Eldin H.; Ali, Elham A.

    2013-09-01

    N-(pyridine-2-ylmethylene)benzo[d]thiazol-2-amine Schiff base (L) and its Cu(II), Fe(III), Co(II), Ni(II) and Zn(II) complexes were synthesized and characterized by a set of chemical and spectroscopic measurements using elemental analysis, electrical conductance, mass spectra, magnetic susceptibility and spectral techniques (IR, UV-Vis, 1H NMR). Elemental and mass spectrometric data are consistent with the proposed formula. IR spectra confirm the bidentate nature of the Schiff base ligand. The octahedral geometry around Cu(II), Fe(III), Ni(II) and Zn(II) as well as tetrahedral geometry around Co(II) were suggested by UV-Vis spectra and magnetic moment data. The thermal degradation behavior of the Schiff base and its complexes was investigated by thermogravimetric analysis. The structure of the Schiff base and its transition metal complexes was also theoretically studied using molecular mechanics (MM+). The obtained structures were minimized with a semi-empirical (PM3) method. The in vitro antitumor activity of the synthesized compounds was studied. The Zn-complex exhibits significant decrease in surviving fraction of breast carcinoma (MCF 7), liver carcinoma (HEPG2), colon carcinoma (HCT116) and larynx carcinoma (HEP2) cell lines human cancer.

  18. Synthesis, spectroscopic (electronic, IR, NMR and ESR) and theoretical studies of transition metal complexes with some unsymmetrical Schiff bases

    NASA Astrophysics Data System (ADS)

    Singh, Vinod P.; Singh, Shweta; Singh, Divya P.; Tiwari, K.; Mishra, Monika

    2014-01-01

    Two unsymmetrical Schiff bases, glyoxal salicylaldehyde oxalic acid dihydrazone (gsodh) and glyoxal salicylaldehyde malonic acid dihydrazone (gsmdh) and their Co(II), Ni(II), Cu(II) and Zn(II) complexes have been synthesized. The structures of metal complexes are elucidated on the basis of elemental analyses, molar conductance, magnetic susceptibility measurements, electronic, ESR, IR and NMR (1H and 13C) spectral studies. Both ligands show monobasic tetra-dentate behaviour, bonding through CO, two CN and a phenolate group. The electronic spectral studies in solid state indicate a square planar geometry for Ni(II) and Cu(II) complexes and a tetrahedral geometry for Co(II) complexes. However, Co(II) and Cu(II) complexes adopt octahedral geometry in DMSO solution. The ESR spectra of Cu(II) complexes in DMSO solution at 77 K predict an elongated tetragonal distorted octahedral geometry around metal ion and presence of unpaired electron in d orbital. Further, the structures of ligands and their Ni(II) complexes have been satisfactorily modelled by calculations based on density functional theory (DFT). The electronic spectra of Ni(II) complexes are also analyzed in depth with the help of time dependent-DFT (TD-DFT). The theoretical analyses of electronic structure and molecular orbitals have demonstrated that the high-energy absorption bands are M ? L charge transfer and low energy transitions are d-d transitions.

  19. 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.

  20. 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.

  1. 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.

  2. Synthesis, Characterization, DNA Interaction, and Antitumor Activities of La (III) Complex with Schiff Base Ligand Derived from Kaempferol and Diethylenetriamine

    PubMed Central

    Wang, Qin; Huang, Yu; Zhang, Jin-Sheng; Yang, Xin-Bin

    2014-01-01

    A novel La (III) complex, [LaL(H2O)3]NO3·3H2O, with Schiff base ligand L derived from kaempferol and diethylenetriamine, has been synthesized and characterized by elemental analysis, IR, UV-visible, 1H NMR, thermogravimetric analysis, and molar conductance measurements. The fluorescence spectra, circular dichroism spectra, and viscosity measurements and gel electrophoresis experiments indicated that the ligand L and La (III) complex could bind to CT-DNA presumably via intercalative mode and the La (III) complex showed a stronger ability to bind and cleave DNA than the ligand L alone. The binding constants (Kb) were evaluated from fluorescence data and the values ranged from 0.454 to 0.659 × 105 L mol?1 and 1.71 to 17.3 × 105 L mol?1 for the ligand L and La (III) complex, respectively, in the temperature range of 298–310?K. It was also found that the fluorescence quenching mechanism of EB-DNA by ligand L and La (III) complex was a static quenching process. In comparison to free ligand L, La (III) complex exhibited enhanced cytotoxic activities against tested tumor cell lines HL-60 and HepG-2, which may correlate with the enhanced DNA binding and cleaving abilities of the La (III) complex. PMID:25371657

  3. 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.

  4. Synthesis, spectral, antitumor and antimicrobial studies on Cu(II) complexes of purine and triazole Schiff base derivatives

    NASA Astrophysics Data System (ADS)

    Amer, Said; El-Wakiel, Nadia; El-Ghamry, Hoda

    2013-10-01

    A series of copper (II) complexes of Schiff bases derived from 7H-2,6-diaminopurine and 4H-3,5-diamino-1,2,4-triazole with 2-pyridinecarbaldehyde, salicylaldehyde, 2,4-dihydroxybenzaldehyde and 2-hydroxy-1-naphthaldehyde have been prepared. The donor atoms and the possible geometry of the complexes were investigated by means of elemental and thermal analyses, molar conductance, magnetic moment, UV-Vis, IR, ESR and mass spectra. The ligands behaved as tetradentate, coordinating through the nitrogen atom of the azomethine group and the nearest nitrogen atom to it or oxygen atom of ?-hydroxyl group. The results of simultaneous DTA & TGA analyses of the complexes showed the final degradation product for these complexes is CuO. The spectral studies confirmed a four coordinate environment around the metal ion. The obtained results were supported by 3D molecular modeling of complexes using molecular mechanics (MM+) and semiempirical molecular orbital calculations (PM3). These complexes were also tested for their in vitro antimicrobial activities against some bacterial and fungal strains. Complex 2 was investigated for its cyctotoxic effect against human breast cancer (MCF7), liver carcinoma (HEPG2) and colon carcinoma cell lines (HCT116). This compound exhibited a moderate activity against the tested cell lines with IC50 of 10.3, 9.8 and 8.7 ?g/ml against MCF7, HCT116 and HEPG2, respectively.

  5. Synthesis, spectroscopic characterization and biological evaluation studies of Schiff's base derived from naphthofuran-2-carbohydrazide with 8-formyl-7-hydroxy-4-methyl coumarin and its metal complexes

    NASA Astrophysics Data System (ADS)

    Halli, M. B.; Sumathi, R. B.; Kinni, Mallikarjun

    2012-12-01

    Metal complexes of the type ML2, where M = Co(II), Ni(II), Cu(II), Zn(II), Cd(II), Hg(II) and L = Schiff's base derived from the condensation of naphthofuran-2-carbohydrazide with 8-formyl-7-hydroxy-4-methyl coumarin have been synthesized. The chelation of the complexes have been elucidated in the light of analytical, IR, UV-vis, 1H NMR, mass, ESR spectral data, thermal and magnetic studies. The measured molar conductance values indicate that, the complexes are non-electrolytic in nature. The redox behavior of one of the synthesized metal complexes was investigated by cyclic voltammetry. The Schiff's base and its metal complexes have been screened for their in vitro antibacterial and antifungal activities by MIC method. The DNA cleavage activities of all the complexes were studied by agarose gel electrophoresis method. In addition, the free ligand along with its complexes has been studied for their antioxidant activity.

  6. Synthesis and aggregation behaviour of luminescent mesomorphic zinc(ii) complexes with 'salen' type asymmetric Schiff base ligands.

    PubMed

    Chakraborty, Sutapa; Bhattacharjee, Chira R; Mondal, Paritosh; Prasad, S Krishna; Rao, D S Shankar

    2015-04-01

    A new series of photoluminescent Zn(ii)-salen type asymmetric Schiff base complexes, [ZnL], H2L = [N,N'-bis-(4-n-alkoxysalicylidene)-1,2-diaminopropane] (n = 12, 14 and 16) have been accessed and their mesomorphic and photophysical properties investigated. Though the ligands are non-mesomorphic, coordination to Zn(2+) ion induces liquid crystalline behaviour. The complexes exhibited a lamello-columnar phase (Coll) as characterized by a variable temperature powder X-ray diffraction (XRD) study. Intense blue emissions were observed for the complexes at room temperature in solution, in the solid state and in the mesophase. Aggregation properties of the complexes were explored in different solvents through absorption and photoluminescence studies. While de-aggregation to monomers occurred in coordinating solvents due to axial coordination to Zn(ii), aggregates were formed in the solution of non-coordinating solvents. Density functional theory (DFT) computation carried out on a representative complex using a GAUSSIAN 09 program at the B3LYP level suggested a distorted square planar geometry. The results of a time-dependent DFT (TD-DFT) spectral correlative study showed the electronic properties of the complex molecule to be in compliance with the spectral data. PMID:25803004

  7. Studies on DNA binding behaviour of biologically active transition metal complexes of new tetradentate N2O2 donor Schiff bases: Inhibitory activity against bacteria

    NASA Astrophysics Data System (ADS)

    Sobha, S.; Mahalakshmi, R.; Raman, N.

    A series of Cu(II), Ni(II) and Zn(II) complexes of the type ML have been synthesized with Schiff bases derived from o-acetoacetotoluidide, 2-hydroxybenzaldehyde and o-phenylenediamine/1,4-diaminobutane. 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 six 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 bases are found to act as tetradentate ligands using N2O2 donor set of atoms leading to a square-planar geometry for the complexes around all the metal ions. The binding properties of metal complexes with DNA were investigated by absorption spectra, viscosity measurements and cyclic voltammetry. Detailed analysis reveals that the metal complexes intercalate into the DNA base stack as intercalators. All the metal complexes cleave the pUC19 DNA in presence of H2O2. The Schiff bases and their complexes have been screened for their antibacterial activity against five bacterial strains (Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Staphylococcus epidermidis, Klebsiella pneumoniae) by disk diffusion method. All the metal complexes have potent biocidal activity than the free ligands.

  8. A novel bioactive tyramine derived Schiff base and its transition metal complexes as selective DNA binding agents

    NASA Astrophysics Data System (ADS)

    Raman, N.; Sobha, S.; Thamaraichelvan, A.

    2011-02-01

    A novel tyramine derived Schiff base, 3-4-dimethoxybenzylidene-4-aminoantipyrinyl-4-aminoethylphenol(L) and a series of its transition metal complexes of the type, ML 2Cl 2 where, M = Cu(II), Ni(II), Co(II) and Zn(II) have been designed and synthesized. Their structural features and other properties were deduced from the elemental analysis, magnetic susceptibility and molar conductivity as well as from mass, IR, UV-vis, 1H NMR and EPR spectral studies. The binding properties of these complexes with calf thymus DNA (CT-DNA) were investigated using electronic absorption spectroscopy, viscosity measurement, cyclic voltammetry and molecular docking analysis. The results reveal that the metal(II) complexes interact with DNA through minor groove binding. The interaction has also been investigated by gel electrophoresis. Interestingly, it was found that all the complexes could cleave the circular plasmid pUC19 super coiled (SC) DNA efficiently in the presence of AH 2 (ascorbic acid). The complexes showed enhanced antifungal and antibacterial activities compared to the free ligand.

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

    PubMed

    Prakash, Govindan; Viswanathamurthi, Periasamy

    2014-08-14

    Schiff base disulfide ligands (H2L(1-6)) were synthesized from the condensation of cystamine with salicylaldehyde(H2L(1)), 5-chlorosalicylaldehyde(H2L(2)), o-vanillin(H2L(3)), 2-hydroxyacetophenone(H2L(4)), 3-methyl-2-hydroxyacetophenone(H2L(5)), and 2-hydroxy-1-naphthaldehyde(H2L(6)). H2L(1-6) 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)L(1-6)]. Characterization of the new complexes was carried out by using elemental and spectral (IR, UV-Vis, NMR ((1)H and (13)C) 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. PMID:24747860

  10. 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.

  11. Synthesis and Characterization of a New Schiff Base and its Metal Complexes Derived from the Mannich Base, N-(1-piperidinobenzyl)acetamide

    Microsoft Academic Search

    N. Raman; S. Ravichandran

    2005-01-01

    New neutral Schiff base complexes of Cu(II), Co(II), Ni(II), and Zn(II) derived from 4-aminoantipyrine and N-(1-piperidinobenzyl)acetamide (Mannich base) have been synthesized. The structural features of the complexes have been characterized by microanalytical data, IR, UV-Vis, H NMR, ESR, CV, TGA and powder XRD techniques. Electronic absorption spectra of the complexes indicate an octahedral geometry around the metal ion. The neutral

  12. Synthesis, characterization, in vitro antimicrobial and DNA cleavage studies of Co(II), Ni(II) and Cu(II) complexes with ONOO donor coumarin Schiff bases

    NASA Astrophysics Data System (ADS)

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

    2011-01-01

    A series of Co(II), Ni(II) and Cu(II) complexes have been synthesized with Schiff bases derived from 2-hydroxy-1-naphthaldehyde and 2-oxo-2H-chromene-3-carbohydrazide/6-bromo-2-oxo-2H-chromene-3-carbohydrazide. The chelation of the complexes has been proposed in the light of analytical, spectral (IR, UV-Vis, 1H NMR, ESR, FAB-mass and fluorescence), magnetic and thermal studies. The measured molar conductance values indicate that, the complexes are non-electrolytic in nature. The redox behavior of the complexes was investigated with electrochemical method by using cyclic voltammetry. The Schiff bases and their metal complexes have been screened for their in vitro antibacterial ( Escherichia coli, Staphylococcus aureus, Bacillus subtilis and Salmonella typhi) and antifungal activities ( Candida albicans, Cladosporium and Aspergillus niger) by MIC method. The DNA cleavage is studied by agarose gel electrophoresis method.

  13. Environmental Dependence of Artifact CD Peaks of Chiral Schiff Base 3d-4f Complexes in Soft Mater PMMA Matrix

    PubMed Central

    Okamoto, Yu; Nidaira, Keisuke; Akitsu, Takashiro

    2011-01-01

    Four chiral Schiff base binuclear 3d-4f complexes (NdNi, NdCu, GdNi, and GdCu) have been prepared and characterized by means of electronic and CD spectra, IR spectra, magnetic measurements, and X-ray crystallography (NdNi). A so-called artifact peak of solid state CD spectra, which was characteristic of oriented molecules without free molecular rotation, appeared at about 470 nm. Magnetic data of the complexes in the solid state (powder) and in PMMA cast films or solutions indicated that only GdCu preserved molecular structures in various matrixes of soft maters. For the first time, we have used the changes of intensity of artifact CD peaks to detect properties of environmental (media solid state (KBr pellets), PMMA cast films, concentration dependence of PMMA in acetone solutions, and pure acetone solution) for chiral 3d-4f complexes (GdCu). Rigid matrix keeping anisotropic orientation exhibited a decrease in the intensity of the artifact CD peak toward negative values. The present results suggest that solid state artifact CD peaks can be affected by environmental viscosity of a soft mater matrix. PMID:22072930

  14. Novel Rhenium(III, IV, and V) Tetradentate N2O2 Schiff Base Mononuclear and Dinuclear Complexes

    PubMed Central

    Rotsch, David A.; Reinig, Kimberly M.; Weis, Eric M.; Taylor, Anna B.; Barnes, Charles L.

    2013-01-01

    Reaction of (Bu4N)[ReOCl4] with the tetradentate Schiff base ligand ?, ?’-[(1,1-dimethylethylene)dinitrilo]di-o-cresol (sal2ibnH2) yields cis-[ReVOCl(sal2ibn)], which quickly forms trans-[?-O(ReVO(sal2ibn))2] in solution. The dinuclear complex can also be isolated by the addition of base (Et3N) to the reaction mixture. Conversely, the mononuclear complex can be trapped as cis-[ReVO(NCS)(sal2ibn)] by addition of (Bu4N)SCN to the reaction mixture. Reduction of cis-[ReVO(NCS)sal2ibn] with triphenylphosphine gives the unique trans-[ReIII(NCS)(PPh3)(sal2ibn)] and rare ?-oxo Re(IV) dimer trans-[?-O(ReIV(NCS)(sal2ibn))2]. All of the complexes were characterized by 1H and 13C NMR, FT-IR spectroscopy, electrospray ionization mass spectrometry (ESI-MS), cyclic voltammetry and single crystal X-ray diffraction. PMID:23824208

  15. Novel rhenium(III, IV, and V) tetradentate N2O2 Schiff base mononuclear and dinuclear complexes.

    PubMed

    Rotsch, David A; Reinig, Kimberly M; Weis, Eric M; Taylor, Anna B; Barnes, Charles L; Jurisson, Silvia S

    2013-08-28

    Reaction of (Bu4N)[ReOCl4] with the tetradentate Schiff base ligand ?,?'-[(1,1-dimethylethylene)dinitrilo]di-o-cresol (sal2ibnH2) yields cis-[Re(V)OCl(sal2ibn)], which quickly forms trans-[?-O(Re(V)O(sal2ibn))2] in solution. The dinuclear complex can also be isolated by the addition of base (Et3N) to the reaction mixture. Conversely, the mononuclear complex can be trapped as cis-[Re(V)O(NCS)(sal2ibn)] by addition of (Bu4N)SCN to the reaction mixture. Reduction of cis-[Re(V)O(NCS)sal2ibn] with triphenylphosphine gives the rare trans-[Re(III)(NCS)(PPh3)(sal2ibn)] and unique ?-oxo Re(IV) dimer trans-[?-O(Re(IV)(NCS)(sal2ibn))2]. All of the complexes were characterized by (1)H and (13)C NMR, FT-IR spectroscopy, electrospray ionization mass spectrometry (ESI-MS), cyclic voltammetry and single crystal X-ray diffraction. PMID:23824208

  16. Synthesis, characterization and biological activity of some new VO(IV), Co(II), Ni(II), Cu(II) and Zn(II) complexes of chromone based NNO Schiff base derived from 2-aminothiazole

    NASA Astrophysics Data System (ADS)

    Kalanithi, M.; Kodimunthiri, D.; Rajarajan, M.; Tharmaraj, P.

    2011-11-01

    Coordination compounds of VO(IV), Co(II), Ni(II), Cu(II) and Zn(II) with the Schiff base obtained through the condensation of 2-aminothiazole with 3-formyl chromone were synthesized. The compounds were characterized by 1H, 13C NMR, UV-Vis, IR, Mass, EPR, molar conductance and magnetic susceptibility measurements. The Cu(II) complex possesses tetrahedrally distorted square planar geometry whereas Co(II), Ni(II), and Zn(II) show distorted tetrahedral geometry. The VO(IV) complex shows square pyramidal geometry. The cyclic voltammogram of Cu (II) complex showed a well defined redox couple Cu(II)/Cu(I) with quasireversible nature. The antimicrobial activity against the species Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, Bacillus subtilis, Candida albigans and Aspergillus niger was screened and compared to the activity of the ligand. Emission spectrum was recorded for the ligand and the metal(II) complexes. The second harmonic generation (SHG) efficiency was measured and found to have one fourth of the activity of urea. The SEM image of the copper(II) complex implies that the size of the particles is 2 ?m.

  17. 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

  18. Non-symmetrical tetradentate vanadyl Schiff base complexes derived from 1,2-phenylene diamine and 1,3-naphthalene diamine as catalysts for the oxidation of cyclohexene

    Microsoft Academic Search

    Daver M Boghaei; Sajjad Mohebi

    2002-01-01

    Two series of the novel unsymmetrical diimino tetradentate Schiff bases derived from phenylenediamine and 1,3-naphthalene diamine and their vanadyl complexes were synthesized by template and non-template methods and characterized by 1H, 13C NMR, IR, UV–Vis and elemental analysis. These complexes are used as catalysts for the selective aerobic oxidation of cyclohexene. The catalytic activity increases as the number of electron-donor

  19. Zeolite-encapsulated and clay-intercalated metal porphyrin, phthalocyanine and Schiff-base complexes as models for biomimetic oxidation catalysts: an overview

    Microsoft Academic Search

    Fethi Bedioui

    1995-01-01

    This paper reviews some important recent work on the design and characterization of zeolite-encapsulated and clay-intercalated metal-Schiff base, -porphyrin and-phthalocyanine complexes. After an introduction to the chemistry of clays and zeolites, the incorporation methods of these complexes within the mineral materials are discussed and an overview of their physicochemical characterization is reported. A large part of this paper is devoted

  20. Enhancing the copper(II) complexes cytotoxicity to cancer cells through bound to human serum albumin.

    PubMed

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

    2015-03-01

    We use Schiff-base salicylaldehyde benzoylhydrazone (HL) as the ligand for copper(II), resulting in the complexes [CuCl(L)]·H2O (C1), [CuNO3(L)]·H2O (C2) and [CuBr(L)]2 (C3). We characterize the Cu(II) compounds' interactions with human serum albumin (HSA) using fluorescence spectroscopy and molecular docking. These studies revealed that Cu(II) compounds propensity bound to IIA subdomain of HSA possible by hydrophobic interactions and hydrogen bond. Cu(II) compounds produce intracellular reactive oxygen species (ROS) in cancer cells. Complexes of HSA and copper(II) compounds enhance about 2-fold cytotoxicity in cancer cells but do not raise cytotoxicity levels in normal cells in vitro. Compared with C3 alone, HSA-C3 complex promotes HepG2 cell apoptosis and has a stronger capacity to promote cell cycle arrest at the G2/M phase of HepG2. PMID:25573806

  1. Unusual cocrystals made of a Schiff base metal complex and an organic molecule - Close-packing vs. hydrogen bond interactions

    NASA Astrophysics Data System (ADS)

    Buvaylo, Elena A.; Kokozay, Vladimir N.; Rubini, Katia; Vassilyeva, Olga Yu.; Skelton, Brian W.

    2014-08-01

    The mononuclear complexes [ML2]0 (M = Co, Ni, Zn; HL - Schiff base ligand formed in situ from 2-pyridinecarbaldehyde and anthranilic acid, AA) can efficiently interact with unreacted AA molecules to produce CoL2·AA·H2O (1), NiL2·AA·H2O (2) and ZnL2·AA·0.25CH3OH·0.5H2O (3) cocrystals. Compounds 1-3 have been obtained as single crystals and characterized by elemental analysis, IR spectroscopy, thermal analysis, and single-crystal X-ray diffraction techniques. The compounds crystallize in the triclinic space group P1?, with 1 and 2 being isomorphous. Neutral ML2 molecules in 1-3 show no crystallographically imposed symmetry with the metal atoms octahedrally surrounded by two anionic ligands in a mer configuration. Of the two crystallographically distinct AA molecules, one molecule only is engaged in H-bonding N/Osbnd H⋯O interactions with ML2 units. The solid-state organization of the cocrystals is described as an insertion of the organic molecules between the layers of ML2 complexes as they occur in the reported native NiL2·H2O structure.

  2. Phase transition and vapochromism in molecular assemblies of a polymorphic zinc(II) Schiff-base complex.

    PubMed

    Oliveri, Ivan Pietro; Malandrino, Graziella; Di Bella, Santo

    2014-09-15

    This paper reports for the first time the irreversible thermally induced phase transition, accompanied by color change, and the vapochromic behavior of an amphiphilic, Lewis acidic Zn(II) Schiff-base complex, through detailed X-ray diffraction, thermogravimetric analysis and differential scanning calorimetry, and optical absorption studies. The unprecedented irreversible phase transition for such kind of complexes is associated with a thermal, lamellar-to-hexagonal columnar structural transition, which involves a different arrangement of each molecular unit within the assembled structure, H- and J-type aggregates, respectively, responsible for the thermochromic behavior. The vapochromism, investigated either in powder samples or in thermally annealed cast films, is related to the formation of 1:1 adducts upon exposure to vapors of strong Lewis bases and implies dramatic optical absorption variations and naked-eye observation of the change in color from red-brown to red. The chemisorption process is fast, completely reversible, reproducible, and selective for amines. The reversible switching of the chemisorption-desorption process in cast films is demonstrated by successive cycles, amine exposure and subsequent heating, by monitoring the substantial optical absorption changes in the visible region. Vapochromism of this material can potentially be used to detect vapors of volatile amines. PMID:25148651

  3. 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

  4. Conformational change of a chiral Schiff base Ni(II) complex with a binaphthyl moiety: application of vibrational circular dichroism spectroscopy.

    PubMed

    Sato, Hisako; Mori, Yukie; Yamagishi, Akihiko

    2013-05-21

    Vibrational circular dichroism (VCD) spectroscopy was applied to study the structural change of a Ni(II) complex (denoted by [Ni(II)L]) with a chiral Schiff base ligand, (R)- or (S)-2,2'-bis(salicylideneamino)-1,1'-binaphthyl (denoted by H2L), in solution. The major signals in the mid-IR region were assigned on the basis of comparison with the DFT-calculated spectra. The complex transformed reversibly between the square-planar, tetrahedral and octahedral configurations, depending on solvents and temperature. The observed changes in the VCD peaks accompanying the transformation were analyzed in terms of the conformational change of the chiral ligand with a focus on the twisting angle in the Schiff base backbone and the dihedral angle of the binaphthyl group. PMID:23503591

  5. Zn(II), Ni(II), Cu(II) and Pb(II) complexes of tridentate asymmetrical Schiff base ligands: Synthesis, characterization, properties and biological activity

    NASA Astrophysics Data System (ADS)

    ?ahin, Mustafa; Koçak, Nuriye; Erdenay, Damla; Arslan, U?ur

    2013-02-01

    New asymmetrical tridentate Schiff base ligands were synthesized using 1,2-phenylenediamine, 4-methyl-1,2-phenylenediamine, 2-hydroxy-1-napthaldehyde, 9-anthracenecarboxaldehyde. Schiff base ligands and their metal complexes were synthesised and characterized by using FT-IR, 1H NMR, 13C NMR, UV-Vis, XRD, ESR, elemental analysis and fluorescence studies. The antimicrobial activity of the ligands and their metal complexes were studied against Staphylococcus aureus ATCC 29213, S. aureus ATCC 25923, Streptococcus mutans RSHM 676, Enterococcus faecalis ATCC 29212, Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853. The determination of the antibacterial activity was done using the broth microdilution methods. In general, it has been determined that the studied compounds have MIC values similar to Gram-positive and Gram-negative bacteria. It has been found that Ni, Pb, Zn derivatives of HL1A and ZnL2A has lower MIC values than ampicillin for P. aeruginosa ATCC 27853 strain.

  6. A novel salicylate-selective electrode based on a Sn(IV) complex of salicylal-imino acid Schiff base.

    PubMed

    Xu, Lan; Yuan, Ruo; Chai, Ya-Qin; Wang, Xiu-Ling

    2005-02-01

    A novel poly(vinyl chloride) membrane electrode with high selectivity toward salicylate (Sal-), based on the use of the salicylal-imino acid Schiff base dibenyl complex of Sn(IV) [Sn(IV)-SIADBen] as ionophore is described. The influence of lipophilic charged additives on the performance of the electrode was studied. The results suggested that Sn(IV)-SIADBen according to a positively-charged carrier mechanism. The influence of several other variables was investigated in order to optimize the potentiometric response and selectivity of the electrode. The electrode based on Sn(IV)-SIADBen, with 30.44 wt% PVC, 64.55 wt% plasticizer [dioctyl phthalate (DOP)], 3.81 wt% ionophore, and 1.2 wt% anionic additive exhibited a linear response for the Sal- ion over the concentration range 1.0x10(-1) to 2.5x10(-6) mol l-1, and displayed an anti-Hofmeister selectivity sequence as follows: salicylate>perchlorate>thiocyanate>benzoate>iodide>nitrate>chloride>nitrite approximately acetate>citrate>sulfate. UV-Visible absorption spectra were used to examine the specific interaction of salicylate with the ionophore. The electrode was applied to clinical medical analysis, and the results obtained were consistent with those obtained by conventional methods. PMID:15668810

  7. Potentiometric membrane electrode for salicylate based on an organotin complex with a salicylal Schiff base of amino acid.

    PubMed

    Xu, Lan; Yuan, Ruo; Fu, Ying-Zi; Chai, Ya-Qin

    2005-03-01

    A novel salicylate-selective electrode based on an organotin complex with a salicylal Schiff base of amino acid salicylaldehydeaminoacid-di-n-butyl-Sn(IV) [Sn(IV)-SAADB] as ionophore is described, which exhibits high selectivity for salicylate over many other common anions with an anti-Hofmeister selectivity sequence: Sal- > PhCOO- > SCN- > Cl04- > I- > NO3- > NO2- > Br- > Cl- > CH3COO-. The electrode, based on Sn(IV)-SAADB, with a 30.44 wt% PVC, a 65.45 wt% plasticizer (dioctyl phthalate, DOP), a 3.81 wt% ionophore and a 0.3 wt% anionic additive is linear in 6.0 x 10(-6) - 1.0 x 10(-1) mol l(-1) with a detection limit of 2.0 x 10(-6) mol l(-1) and a slope of 62.0 +/- 1.2 mV/decade of salicylate concentration in a phosphate buffer solution of pH 5.5 at 25 degrees C. The influence on the electrode performances by lipophilic charged additives was studied, and the possible response mechanism was investigated by UV spectra. The electrode was applied to medicine analysis and the result obtained has been satisfactory. PMID:15790114

  8. A systematic investigation on biological activities of a novel double zwitterionic Schiff base Cu(II) complex

    NASA Astrophysics Data System (ADS)

    Thalamuthu, S.; Annaraj, B.; Neelakantan, M. A.

    2014-01-01

    Double zwitterionic amino acid Schiff base, o-vanillylidene-L-histidine (OVHIS) and its copper complex (CuOVHIS) have been synthesized and characterized. CuOVHIS has distorted octahedral geometry, and OVHIS coordinates the copper ion in a tetradentate manner (N2O2). The pKa of OVHIS in aqueous solution was studied by potentiometric and spectrophotometric methods. DNA binding behavior of the compounds was investigated using spectrophotometric, cyclic voltammetric, and viscosity methods. The efficacy of DNA cleaving nature was tested on pUC19 DNA. The in vitro biological activity was tested against various micro organisms. The effect of CuOVHIS on the surface feature of Escherichia coli was analyzed by SEM. DPPH assay studies revealed that CuOVHIS has higher antioxidant activity. OVHIS inhibits proliferation of HCT117 cells with half maximal inhibition (IC50) of 71.15 ± 0.67. Chelation of OVHIS with Cu(II) ion enhances the inhibition of proliferation action (IC50 = 53.14 ± 0.67).

  9. Crystal structure of Ni(II) complex and fluorescence properties of Zn(II) complex with the Schiff base derived from diethenetriamine and PMBP

    Microsoft Academic Search

    Yuan Wang; Zheng-Yin Yang

    2008-01-01

    The Schiff base, H2L, was derived from 1-phenyl-3-methyl-4-benzoyl-5-pyrazolone (PMBP) and diethenetriamine. The crystal structure of [NiL(C2H5OH)]·H2O obtained from ethanol solution was determined by X-ray diffraction analysis. The coordination geometry of Ni(II) ion is a distorted octahedron with three oxygen atoms and three nitrogen atoms. Under the excitation of ultraviolet light, strong fluorescence of solid Zn(II) complex was observed. In addition,

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

    PubMed

    Keskio?lu, Eren; Gündüzalp, Ayla Balaban; Cete, 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, (1)H-(13)C 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(2)O, 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(2)O)(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. PMID:17904895

  11. Tetra- and hexadentate Schiff base ligands and their Ni(II), Cu(II) and Zn(II) complexes. Synthesis, spectral, magnetic and thermal studies

    NASA Astrophysics Data System (ADS)

    Ismail, Tarek M. A.; Saleh, Akila A.; Ghamry, Mosad A. El

    2012-02-01

    Tetradentate N 2O 2, N 4 Schiff bases, 1,2-bis(4-oxopent-2-ylideneamino) benzene (BOAB), 1-(4-oxopent-2-ylideneamino-2-[(2-hydroxyphenyl)ethylideneamino] benzene (OAHAB), 7,16-bis(4-chlorobenzylidene)-6,8,15,17-tetra-methyl-7,16-dihydro -5,9,14,18-tetraza-dibenzo[a,h] cyclo tetradecene (BCBDCT), 7,16-bis(2-hydroxy-benzylidene)-6,8,15,17-tetramethyl-7,16-dihydro-5,9,14,18-tetraza-dibenzo [a,h] cyclo tetradecene (BHBDCT) and hexadentate N 4O 2 Schiff bases, 2,4-bis {2-[1-(2-hydroxyphenyl) ethylideneamino] phenylimino}-3-(2-hydroxybenzylidene) pentane (BHAPHP), 2,4-bis {2-[1-(2-hydroxyphenyl) ethylideneamino] phenylimino}-3-(4-chlorobenzylidene) pentane (BHAPCP) were prepared and characterized by elemental analysis, IR, UV-Vis, 1H NMR and mass spectra. The solid complexes of the prepared Schiff base ligands with Ni(II), Cu(II) and Zn(II) ions were isolated and characterized by elemental and thermal analyses, IR, electronic and ESR spectra as well as conductance and magnetic susceptibility measurements. The results showed that most complexes have octahedral geometry but few can attain the tetrahedral arrangement. The TG analyses suggest high stability for most complexes followed by thermal decomposition in different steps. The kinetic and thermodynamic parameters for decomposition steps in Cu(II) complexes thermograms have been calculated.

  12. Switching and redox isomerism in first-row transition metal complexes containing redox active Schiff base ligands.

    PubMed

    Sasmal, Ashok; Garribba, Eugenio; Gómez-García, Carlos J; Desplanches, Cédric; Mitra, Samiran

    2014-11-14

    The reversible redox isomerisms in first row transition metal complexes of the type ML2 were studied. The six ML2 complexes (M = Mn(III) (), Fe(II) (), Co(III) (), Ni(II) (), Cu(II) () and Zn(II) ()) were synthesized with a redox active Schiff base ligand [2-(3,5-di-tert-butyl-2-hydroxyphenylamino)-4-chlorophenol] (H3L) presenting different oxidation states from -2 to 0 (L(2-), L(-) and L(0)). EPR spectra and magnetic susceptibility measurements indicate the presence of complexes of the type [Mn(III)(L(2-))(L(-))] () with S = 1/2, [Fe(II)(L(-))2] () with S = 2, [Co(III)(L(2-))(L(-))] () with S = 1/2, [Ni(II)(L(-))2] () with S = 1, [Cu(II)(L(-))2] () with S = 1/2 and [Zn(II)(L(-))2] () with S = 0 at high temperatures. Temperature and solvents influence the electronic structures of the species and give several valence tautomers. At low temperatures these complexes present thermally induced metal-to-ligand (, , ) or ligand-to-ligand (in , ) electron transfer (partial or total), resulting in compounds of the type [Mn(IV)(L(2-))2] () with S = 1/2, [Fe(III)(L(-))(L(2-))] () with S = 1, [Ni(III)(L(2-))(L(-))] () with S = 0, [Cu(II)(L(2-))(L(0))] () with S = 1/2 and [Zn(II)(L(2-))(L(0))] () with S = 1. This electron transfer is in agreement with the general trend in the redox potentials of the first row transition metal ions from Mn(ii) to Zn(ii), and it allows us to prepare and stabilize reversibly switchable tautomeric forms in transition metal complexes with redox-active ligands. PMID:25233051

  13. Synthesis, spectroscopic characterization and DNA nuclease activity of Cu(II) complexes derived from pyrazolone based NSO-donor Schiff base ligands

    Microsoft Academic Search

    Komal M. Vyas; Rushikesh G. Joshi; R. N. Jadeja; C. Ratna Prabha; Vivek K. Gupta

    2011-01-01

    Two neutral mononuclear Cu(II) complexes have been prepared in EtOH using Schiff bases derived from 4-toluoyl pyrazolone and thiosemicarbazide. Both the ligands have been characterized on the basis of elemental analysis, IR, 1H NMR, 13C NMR and mass spectral data. The molecular geometry of one of these ligands has been determined by single crystal X-ray study. It reveals that these

  14. Diorganotin(IV) complexes of biologically potent 4( 3H)-quinazolinone derived Schiff bases: Synthesis, spectroscopic characterization, DNA interaction studies and antimicrobial activity

    NASA Astrophysics Data System (ADS)

    Prasad, Kollur Shiva; Kumar, Linganna Shiva; Chandan, Shivamallu; Jayalakshmi, Basvegowda; Revanasiddappa, Hosakere D.

    2011-10-01

    Four Schiff base ligands and their corresponding organotin(IV) complexes have been synthesized and characterized by elemental analyses, IR, 1H NMR, MS and thermal studies. The Schiff bases are obtained by the condensation of 3-amino-2-methyl-4( 3H)-quinazolinone with different substituted aldehydes. The elemental analysis data suggest the stoichiometry to be 1:1 ratio formation. Infrared spectral data agreed with the coordination to the central metal ion through imine nitrogen, lactam oxygen and deprotonated phenolic oxygen atoms. All the synthesized compounds have been evaluated for antimicrobial activity against selected species of microorganisms. In addition, DNA binding/cleavage capacity of the compounds was analyzed by absorption spectroscopy, viscosity measurements and gel electrophoresis methods.

  15. Synthesis of new cobalt(III) Schiff base complex: A new precursor for preparation Co3O4 nanoparticles via solid-state thermal decomposition

    NASA Astrophysics Data System (ADS)

    Khalaji, Aliakbar Dehno; Nikookar, Mahsa; Fejfarova, Karla; Dusek, Michal

    2014-08-01

    A new mononuclear octahedral cobalt(III) Schiff base complex [CoL3] (L = N-salicylidin-2-chloroethylimine) has been synthesized and characterized by elemental analyses (CHN) and FT-IR spectroscopy and used as precursor for preparation of Co3O4 nanoparticles. The crystal structure of this compound has been determined by single-crystal X-ray diffraction. The coordination sphere about cobalt(III) ion consists of three phenolato oxygens and three imino nitrogen atoms from three Schiff base ligands, thus forming a distorted octahedral geometry. Each Schiff base ligand acts as a chelate using phenolato oxygen and imino nitrogen. Subsequently, pure phase Co3O4 nanoparticles, with an average size in the range 10-20 nm, were obtained by solid-state thermal decomposition of the synthesized complex at 450 °C under air atmosphere for 3 h. The Co3O4 nanoparticles were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM).

  16. Novel Organotin(IV)-Schiff Base Complexes: Synthesis, Characterization, Antimicrobial Activity, and DNA Interaction Studies.

    PubMed

    Prasad, K Shiva; Kumar, L Shiva; Prasad, Melvin; Revanasiddappa, Hosakere D

    2010-01-01

    Four organotin(IV) complexes with 2-(2-hydroxybenzylideneamino)isoindoline-1,3-dione (L(1)), and 4-(4-hydroxy-3-methoxybenzylideneamino-N-(pyrimidin-2-yl)benzenesulfonamide (L(2)) were synthesized and well characterized by analytical and spectral studies. The synthesized compounds were tested for antimicrobial activity by disc diffusion method. The DNA binding of the complexes 1 and 3 with CT-DNA has been performed with absorption spectroscopy, which showed that both the complexes are avid binders of CT-DNA. Also the nuclease activity of complexes 1 and 3 with plasmid DNA (pUC19) was studied using agarose gel electrophoresis. The complex 1 can act as effective DNA cleaving agent when compared to complex 3 resulting in the nicked form of DNA under physiological conditions. The gel was run both in the absence and presence of the oxidizing agent. PMID:21253533

  17. Novel Organotin(IV)-Schiff Base Complexes: Synthesis, Characterization, Antimicrobial Activity, and DNA Interaction Studies

    PubMed Central

    Prasad, K. Shiva; Kumar, L. Shiva; Prasad, Melvin; Revanasiddappa, Hosakere D.

    2010-01-01

    Four organotin(IV) complexes with 2-(2-hydroxybenzylideneamino)isoindoline-1,3-dione (L1), and 4-(4-hydroxy-3-methoxybenzylideneamino-N-(pyrimidin-2-yl)benzenesulfonamide (L2) were synthesized and well characterized by analytical and spectral studies. The synthesized compounds were tested for antimicrobial activity by disc diffusion method. The DNA binding of the complexes 1 and 3 with CT-DNA has been performed with absorption spectroscopy, which showed that both the complexes are avid binders of CT-DNA. Also the nuclease activity of complexes 1 and 3 with plasmid DNA (pUC19) was studied using agarose gel electrophoresis. The complex 1 can act as effective DNA cleaving agent when compared to complex 3 resulting in the nicked form of DNA under physiological conditions. The gel was run both in the absence and presence of the oxidizing agent. PMID:21253533

  18. 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.

  19. Ferrocenyl-substituted Schiff base complexes of boron: synthesis, structural, physico-chemical and biochemical aspects.

    PubMed

    Yadav, Sunita; Singh, R V

    2011-01-01

    Biological important complexes of boron(III) derived from 1-acetylferrocenehydrazinecarboxamide (L1H), 1-acetylferrocenehydrazinecarbothioamide (L2H) and 1-acetylferrocene carbodithioic acid (L3H) have been prepared and investigated using a combination of microanalytical analysis, melting point, electronic, IR, 1H NMR and 13C NMR spectral studies, cyclic voltammetry and X-ray powder diffraction studies. Boron isopropoxide interacts with the ligands in 1:1, 1:2 and 1:3 molar ratios (boron:ligand) resulting in the formation of coloured products. On the basis of conductance and spectral evidences, tetrahedral structures for boron(III) complexes have been assigned. The ligands are coordinated to the boron(III) via the azomethine nitrogen atom and the thiolic sulfur atom/enolic oxygen atom. On the basis of X-ray powder diffraction study one of the representative boron complex was found to have orthorhombic lattice, having lattice parameters: a=9.9700, b=15.0000 and c=7.0000. Both the ligands and their complexes have been screened for their biological activity on several pathogenic fungi and bacteria and were found to possess appreciable fungicidal and bactericidal properties. Plant growth regulating activity of one of the ligand and its complexes has also been recorded on gram plant, and results have been discussed. PMID:21167770

  20. Rhenium(V) oxo complexes with acetylacetone derived Schiff bases: structure and catalytic epoxidation.

    PubMed

    Sachse, Anna; Mösch-Zanetti, Nadia C; Lyashenko, Ganna; Wielandt, J Wolfram; Most, Kerstin; Magull, Jörg; Dall'Antonia, Fabio; Pal, Aritra; Herbst-Irmer, Regine

    2007-08-20

    Substitution reactions of rhenium(V) oxo precursors [ReOCl3(PPh3)2] or [NBu4][ReOCl4] with the bidentate acetylacetone-derived ketoamine ligands APOH = 4-anilino-3-penten-2-one, DPOH = 4-[2,6-dimethylanilino]-3-penten-2-one, and MTPOH = 4-[2-(methylthio)anilino]-3-penten-2-one gave the complexes [ReO(APO)Cl2(PPh3)] (1), [ReO(DPO)Cl2(PPh3)] (2), and [NBu4][ReOLCl3] (3, L = APO; 4, L = DPO; 5, L = MTPO), respectively. All complexes exhibit only one ketoamino chelate, independent of the amount of ligand added to the rhenium precursors. The complexes were characterized by 1H and 13C NMR spectroscopy. X-ray crystal structures of the complexes 1, 2, 4, and 5, including that of MTPOH, were determined, revealing the trans position of the two oxygen atoms and the trans-Cl,Cl conformation in 1 and 2, in contrast to most other rhenium complexes of this type where the cis-Cl,Cl conformation is observed. Coordination of the potentially tridentate ligand MTPOH in 5 is bidentate with a dangling thioether substituent. Compound 2 shows catalytic activity in the oxidation of cis-cyclooctene with tert-butylhydroperoxide. PMID:17655288

  1. Bactericidal activity of different oxovanadium(IV) complexes with Schiff bases and application of chelation theory.

    PubMed

    Panchal, Pragnesh K; Parekh, Hitesh M; Pansuriya, Pramod B; Patel, Mohan N

    2006-04-01

    Oxovanadium(IV) complexes have been synthesized and characterized the general composition [VOL(A)], where H2L = salicylidene-o-aminothiophenol A1 = bis(benzylidene)ethylenediamine, A2 = bis(acetophenone)ethylenediamine, A3 = 2,2'-bipyridylamine, A4 = bis(benzylidene) - 1,8-diaminonaphthalene, A5 = thiophene-o-carboxaldeneaniline and A6 = thiophene-o-carboxaldene-p-anisidine. Spectral studies indicate that the oxovanadium(IV) complexes assume a six-coordinate octahedral geometry. The antibacterial activities of the complexes against Salmonella typhi, Escherichia coli and Serratia mercescens are higher as compared to the free ligands, vanadyl sulphate, and the control (DMSO) but of moderate activity as compared to the standard drug (tetracycline). PMID:16789434

  2. Spin crossover in mononuclear and binuclear iron(III) complexes with pentadentate Schiff-base ligands

    NASA Astrophysics Data System (ADS)

    Bo?a, Roman; Fukuda, Yutaka; Gembický, Milan; Herchel, Radovan; Jaroš?iak, Rastislav; Linert, Wolfgang; Renz, Franz; Yuzurihara, Jyunko

    2000-07-01

    A series of mononuclear hexacoordinate iron(III) complexes, [Fe( 5L)(py)]BPh 4, and binuclear hexacoordinate iron(III) complexes, [( 5L)Fe(? 2-bpy)Fe( 5L)](BPh 4) 2, has been prepared and their magnetic properties were investigated; the pentadentate ligands were derivatives of 5L=saldptn=N,N'-bis(2-hydroxybenzyliden)-1,7-diamino-4-azaheptane. Temperature variation of the effective magnetic moment for them shows that a spin transition from the low-spin to the high-spin state occurs. The magnetic data were fitted to an Ising-like model appropriate for the mono- and binuclear systems.

  3. Solid state photoluminescence of novel lanthanide complexes based on 4-benzoylpyrazolone Schiff base

    Microsoft Academic Search

    Arkadiusz Listkowski; Marek Pietraszkiewicz; Gianluca Accorsi; John Mohanraj

    2010-01-01

    A novel, promising ligand for luminescent lanthanide complexes tris-((4-(3-methyl-1-phenyl-5-pyrazolonyl)-phenylmethylidene)-2-aminoethyl)amine (trenPMBP) was prepared and used as effective “antenna” for the ligand-sensitized photoluminescence of Tb3+, Dy3+ and Sm3+ ions. All the complexes show surprisingly intensive photoluminescence in comparison with their simple 4-benzoyl-3-methyl-1-phenyl-5-pyrazolone analogues. One of the reasons of such result can be a relatively high located triplet energy level of trenPMBP around

  4. 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).

  5. A new structurally characterized organotin/Schiff-base complex with approximately rectangular molecular boxes formed through hydrogen bonds

    NASA Astrophysics Data System (ADS)

    Zhou, Yun-shan; Zhang, Li-juan; Zeng, Xi-rui; Vital, J. J.; You, Xiao-Zeng

    2000-10-01

    A new organotin/Schiff-base compound, C 24H 25Cl 4NO 3Sn·0.5C 6H 6 ( 1), was prepared by the reaction of ?- n-butoxycarbonylethyltin trichlorides ( 2) with 2-hydroxy-1-naphthalideneaniline-4-Cl ( 3) in benzene, and characterized by single-crystal X-ray diffraction, IR, 1H NMR, and elemental analysis. Yellow rectangular rods of the title compound crystallize as a benzene solvate of formula C 24H 25Cl 4NO 3Sn·0.5C 6H 6 ( 1) in the triclinic space group P-1. The unit cell has dimensions a=9.3624(2) Å, b=12.4947(3) Å, c=13.4821(3) Å, ?=70.7660(10)°, ?=87.1870(10)°, ?=75.1270(10)°, V=1438.13(6) Å3, and Z=2. The structure was solved by direct method primarily and difmap secondarily. It is found that the OH hydrogen in free 2-hydroxy-1-naphthalideneaniline tautomerizes to the imine nitrogen due to the coordination of the phenolic oxygen atom with the Sn atom after the complex formation, while an intramolecular hydrogen bond still exists between O and N ( N⋯O=2.585(4) Å). The Sn atom is coordinated with three chloride atoms, one carbon atom and two oxygen atoms, resulting in a distorted octahedra. The most notable feature of 1 lies in the ?-? interaction among the approximately planer 2-oxygen-1-naphthalideneaniline moieties and the rectangular molecular boxes formed through hydrogen bonds in which the benzene molecules reside.

  6. Near-infrared luminescent PMMA-supported metallopolymers based on Zn-Nd Schiff-base complexes.

    PubMed

    Zhang, Zhao; Feng, Weixu; Su, Peiyang; Lü, Xingqiang; Song, Jirong; Fan, Daidi; Wong, Wai-Kwok; Jones, Richard A; Su, Chengyong

    2014-06-16

    On the basis of self-assembly from the divinylphenyl-modified Salen-type Schiff-base ligands H2L(1) (N,N'-bis(5-(3'-vinylphenyl)-3-methoxy-salicylidene)ethylene-1,2-diamine) or H2L(2) (N,N'-bis(5-(3'-vinylphenyl)-3-methoxy-salicylidene)phenylene-1,2-diamine) with Zn(OAc)2·2H2O and Ln(NO3)3·6H2O in the presence of pyridine (Py), two series of heterobinuclear Zn-Ln complexes [Zn(L(n))(Py)Ln(NO3)3] (n = 1, Ln = La, 1; Ln = Nd, 2; or Ln = Gd, 3 and n = 2, Ln = La, 4; Ln = Nd, 5; or Ln = Gd, 6) are obtained, respectively. Further, through the physical doping and the controlled copolymerization with methyl methacrylate (MMA), two kinds of PMMA-supported hybrid materials, doped PMMA/[Zn(L(n))(Py)Ln(NO3)3] and Wolf Type II Zn(2+)-Ln(3+)-containing metallopolymers Poly(MMA-co-[Zn(L(n))(Py)Ln(NO3)3]), are obtained, respectively. The result of their solid photophysical properties shows the strong and characteristic near-infrared (NIR) luminescent Nd(3+)-centered emissions for both PMMA/[Zn(L(n))(Py)Nd(NO3)3] and Poly(MMA-co-[Zn(L(n))(Py)Nd(NO3)3]), where ethylene-linked hybrid materials endow relatively higher intrinsic quantum yields due to the sensitization from both (1)LC and (3)LC of the chromorphore than those from only (1)LC in phenylene-linked hybrid materials, and the concentration self-quenching of Nd(3+)-based NIR luminescence could be effectively prevented for the copolymerized hybrid materials in comparison with the doped hybrid materials. PMID:24871052

  7. 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

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

    PubMed

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

    2015-07-01

    The tetradentate Schiff base ligands (L(1)-L(4)), 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 (1)H 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: [Formula: see text]. PMID:25813179

  9. Design, characterization, teratogenicity testing, antibacterial, antifungal and DNA interaction of few high spin Fe(II) Schiff base amino acid complexes

    NASA Astrophysics Data System (ADS)

    Abdel-Rahman, Laila H.; El-Khatib, Rafat M.; Nassr, Lobna A. E.; Abu-Dief, Ahmed M.; Lashin, Fakhr El-Din

    2013-07-01

    In this study, new Fe(II) Schiff base amino acid chelates derived from the condensation of o-hydroxynaphthaldehyde with L-alanine, L-phenylalanine, L-aspartic acid, L-histidine and L-arginine were synthesized and characterized via elemental, thermogravimetric analysis, molar conductance, IR, electronic, mass spectra and magnetic moment measurements. The stoichiometry and the stability constants of the complexes were determined spectrophotometrically. Correlation of all spectroscopic data suggested that Schiff bases ligands exhibited tridentate with ONO sites coordinating to the metal ions via protonated phenolic-OH, azomethine-N and carboxylate-O with the general formulae [Fe(HL)2]·nH2O. But in case of L-histidine, the ligand acts as tetradentate via deprotonated phenolic-OH, azomethine-N, carboxylate-O and N-imidazole ring ([FeL(H2O)2]·2H2O), where HL = mono anion and L = dianion of the ligand. The structure of the prepared complexes is suggested to be octahedral. The prepared complexes were tested for their teratogenicity on chick embryos and found to be safe until a concentration of 100 ?g/egg with full embryos formation. Moreover, the interaction between CT-DNA and the investigated complexes were followed by spectrophotometric and viscosity measurements. It was found that, the prepared complexes bind to DNA via classical intercalative mode and showed a different DNA activity with the sequence: nhi > nari > nali > nasi > nphali. Furthermore, the free ligands and their complexes are screened for their in vitro antibacterial and antifungal activity against three types of bacteria, Escherichia coli, Pseudomonas aeruginosa and Bacillus cereus and three types of anti fungal cultures, Penicillium purpurogenium, Aspergillus flavus and Trichotheium rosium in order to assess their antimicrobial potential. The results show that the metal complexes are more reactive with respect to their corresponding Schiff base amino acid ligands.

  10. 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

  11. Synthesis, characterization, single crystal X-ray determination, fluorescence and electrochemical studies of new dinuclear nickel(II) and oxovanadium(IV) complexes containing double Schiff base ligands.

    PubMed

    Shafaatian, Bita; Ozbakzaei, Zahra; Notash, Behrouz; Rezvani, S Ahmad

    2015-04-01

    A series of new bimetallic complexes of nickel(II) and vanadium(IV) have been synthesized by the reaction of the new double bidentate Schiff base ligands with nickel acetate and vanadyl acetylacetonate in 1:1M ratio. In nickel and also vanadyl complexes the ligands were coordinated to the metals via the imine N and enolic O atoms. The complexes have been found to possess 1:1 metals to ligands stoichiometry and the molar conductance data revealed that the metal complexes were non-electrolytes. The nickel and vanadyl complexes exhibited distorted square planar and square pyramidal coordination geometries, respectively. The emission spectra of the ligands and their complexes were studied in methanol. Electrochemical properties of the ligands and their metal complexes were also investigated in DMSO solvent at 150mVs(-1) scan rate. The ligands and metal complexes showed both quasi-reversible and irreversible processes at this scan rate. The Schiff bases and their complexes have been characterized by FT-IR, (1)H NMR, UV/Vis spectroscopies, elemental analysis and conductometry. The crystal structure of the nickel complex has been determined by single crystal X-ray diffraction. PMID:25613693

  12. The Coordination Chemistry of Dioxouranium(VI): Studies on Some Novel Di and Trinuclear Dioxouranium(VI) Complexes with Pyrazolone Based Schiff Bases

    Microsoft Academic Search

    R. C. Maurya; M. N. Jaiswal; R. Verma; B. Shukla

    1998-01-01

    A new series of eight complexes of dioxouranium(VI) with soma Schiff bases derived from 3-methyl-4-p-nitrobenzoyl-1-phenyl-2-pyrazolin-5-one and certain aromatic amines, viz., p-anisidine (MNBPHP-PAH), m-phenetidine (MNBPHP-MPH), O-toluldine (MNBPHP-OTH), ethylenediamine (MNBFHP-ENDH2), o-phenylenediamine (MNBPHP-OPHDH2), m-phenylenediamine (MNBPHP-MPHDH2), p-enylenediamine (MNBPHP-PPHDH2) or benzidine (MNBPHP-BZH2) have been synthesized. These complexes have been characterized by elemental analyses, molar conductances, magnetic measurements, electronic and infrared spectral studies, and are formulated

  13. Synthesis, structures and fluorescence of nickel, zinc and cadmium complexes with the N,N,O-tridentate Schiff base N-2-pyridylmethylidene-2-hydroxy-phenylamine

    Microsoft Academic Search

    Arpi Majumder; Georgina M. Rosair; Arabinda Mallick; Nitin Chattopadhyay; Samiran Mitra

    2006-01-01

    Mono-, tri- and dinuclear neutral complexes [Ni(HL)(L)]·(ClO4)·0.16(H2O) (1), [ZnLZn(OOCCH3)4ZnL] (2) and [Cd2L2(OCH3CO)2(H2O)2] (3) have been obtained from the reaction between the potentially tridentate N,N,O-donor Schiff base ligand HL, where HL=N-2-pyridylmethylidene-2-hydroxy-phenylamine with nickel, zinc or cadmium salts, respectively. The ligand has been prepared by 1:1 condensation of pyridine-2-carboxaldehyde and 2-aminophenol. The ligand and metal complexes were characterised by elemental analysis, spectroscopic

  14. Ru(II) complexes of N 4 and N 2O 2 macrocyclic Schiff base ligands: Their antibacterial and antifungal studies

    NASA Astrophysics Data System (ADS)

    Shanker, Kanne; Rohini, Rondla; Ravinder, Vadde; Reddy, P. Muralidhar; Ho, Yen-Peng

    2009-07-01

    Reactions of [RuCl 2(DMSO) 4] with some of the biologically active macrocyclic Schiff base ligands containing N 4 and N 2O 2 donor group yielded a number of stable complexes, effecting complete displacement of DMSO groups from the complex. The interaction of tetradentate ligand with [RuCl 2(DMSO) 4] gave neutral complexes of the type [RuCl 2(L)] [where L = tetradentate macrocyclic ligand]. These complexes were characterized by elemental, IR, 1H, 13C NMR, mass, electronic, thermal, molar conductance and magnetic susceptibility measurements. An octahedral geometry has been proposed for all complexes. All the macrocycles and macrocyclic Ru(II) complexes along with existing antibacterial drugs were screened for antibacterial activity against Gram +ve ( Bacillus subtilis, Staphylococcus aureus) and Gram -ve ( Escherichia coli, Klebsiella pneumonia) bacteria. All these compounds were found to be more active when compared to streptomycin and ampicillin. The representative macrocyclic Schiff bases and their complexes were also tested in vitro to evaluate their activity against fungi, namely, Aspergillus flavus and Fusarium species.

  15. 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.

  16. Synthesis, spectroscopic and catalytic studies of Cu(II), Co(II) and Ni(II) complexes immobilized on Schiff base modified chitosan

    NASA Astrophysics Data System (ADS)

    Antony, R.; Theodore David Manickam, S.; Saravanan, K.; Karuppasamy, K.; Balakumar, S.

    2013-10-01

    A new class of bidentate (N, O) Schiff base ligand (L) has been derived from the functional biopolymer (chitosan) and 1,2-diphenylethanedione in 1:1 M ratio. This ligand has been used to synthesise the new first row transition metal complexes of Cu(II), Co(II) and Ni(II). The structural properties of the ligand and the synthesized tetra-coordinated complexes have been investigated by elemental analysis, magnetic study, molar conductance measurement and spectroscopic methods viz. FT-IR, UV-Vis., 1H NMR, 13C NMR and XRD. The spectral evidences strongly suggested the square planar geometry to the complexes. The XRD studies proved that crystallinity of chitosan has been diminished after Schiff base formation and metal complexation of L. Thermal and surface properties of the complexes have been also discussed from the investigation of their TG-DTG curves and SEM images, respectively. In addition, the catalytic efficiency of these complexes has been studied in the cyclohexane oxidation reaction using H2O2 as oxidant at 70 °C.

  17. Dinuclear (Fe(II), Gd(III)) complexes deriving from hexadentate Schiff bases: synthesis, structure, and Mössbauer and magnetic properties.

    PubMed

    Costes, Jean-Pierre; Clemente-Juan, Juan Modesto; Dahan, Françoise; Dumestre, Frédéric; Tuchagues, Jean-Pierre

    2002-06-01

    The dinuclear (Fe(II), Gd(III)) complexes studied in this report derive from hexadentate Schiff base ligands abbreviated H(2)L(i)() (i = 1, 2, 3). H(2)L(1) = N,N'-bis(3-methoxysalicylidene)-1,3-diamino-2,2'-dimethyl-propane, H(2)L(2) = N,N'-bis(3-methoxysalicylidene)-1,2-diamino-2-methylpropane, and H(2)L(3) = N,N'-bis(3-methoxysalicylidene)-1,2-diaminoethane. The crystal and molecular structures of three complexes have been determined at 160 K. Depending on the solvent used in the preparation, L(1)Fe(CH(3)OH)Gd(NO(3))(3)(CH(3)OH)(2), 1, or L(1)Fe((CH(3))(2)CO)Gd(NO(3))(3), 1', is obtained from H(2)L(1). A similar complex, L(2)Fe((CH(3))(2)CO)Gd(NO(3))(3), 2, is obtained from H(2)L(2). Complex 1 crystallizes in the orthorhombic space group Pca2(1) (No. 29): a = 22.141(3) A, b = 9.4159(16) A, c = 15.2075(17) A, V = 3170.4(7) A(3), Z = 4. Complexes 1' and 2 crystallize in the monoclinic space group P2(1)/c (No. 14): 1', a = 9.6264(17) A, b = 19.662(3) A, c = 16.039(3) A, beta = 95.15(2) degrees, V = 3023.6(9) A(3), Z = 4; 2, a = 9.7821(13) A, b = 18.7725(17) A, c = 16.100(2) A, beta = 96.497(16) degrees, V = 2937.5(6) A(3), Z = 4. Complexes 1, 1', and 2 possess an Fe(O(phenoxo))(2-)Gd core. The mononuclear L(3)Fe complex could be prepared from H(2)L(3) but not the related dinuclear (Fe, Gd) species. Mössbauer spectroscopy evidences that the iron center is in the +2 oxidation state for the six complexes. The experimental magnetic susceptibility and magnetization data of complexes 1, 1', and 2 indicate the occurrence of weak Fe(II)-Gd(III) ferromagnetic interactions. Single ion zero-field splitting of the iron(II) must be taken into account for satisfactorily fitting the data by exact calculation of the energy levels associated to the spin Hamiltonian through diagonalization of the full matrix for axial symmetry (1, J = 0.50 cm(-1), D = 2.06 cm(-1); 1', J = 0.41 cm(-1), D = 3.22 cm(-1); 2, J = 0.08 cm(-1), D = 4.43 cm(-1)). PMID:12033896

  18. Chemopreventive Evaluation of a Schiff Base Derived Copper (II) Complex against Azoxymethane-Induced Colorectal Cancer in Rats

    PubMed Central

    Hajrezaie, Maryam; Hassandarvish, Pouya; Moghadamtousi, Soheil Zorofchian; Gwaram, Nura Suleiman; Golbabapour, Shahram; NajiHussien, Abdrabuh; Almagrami, Amel Abdullah; Zahedifard, Maryam; Rouhollahi, Elham; Karimian, Hamed; Fani, Somaye; Kamalidehghan, Behnam; Majid, Nazia Abdul; Ali, Hapipah Mohd; Abdulla, Mahmood Ameen

    2014-01-01

    Background Based on the potential of Schiff base compounds to act as sources for the development of cancer chemotherapeutic agents, this in vivo study was performed to investigate the inhibitory properties of the synthetic Schiff base compound Cu(BrHAP)2 on colonic aberrant crypt foci (ACF). Methodology This study involved five groups of male rats. The negative control group was injected with normal saline once a week for 2 weeks and fed 10% Tween 20 for 10 weeks, the cancer control group was subcutaneously injected with 15 mg/kg azoxymethane once per week for two consecutive weeks, the positive control group was injected with 15 mg/kg azoxymethane once per week for two consecutive weeks and 35 mg/kg 5-fluorouracil (injected intra-peritoneally) for 4 weeks, and the experimental groups were first injected with 15 mg/kg azoxymethane once per week for two consecutive weeks and then fed 2.5 or 5 mg/kg of the Schiff base compound once a day for 10 weeks. Application of the Schiff base compound suppressed total colonic ACF formation by up to 72% to 74% (P<0.05) when compared with the cancer control group. Analysis of colorectal specimens revealed that treatments with the Schiff base compound decreased the mean crypt scores in azoxymethane-treated rats. Significant elevations of superoxide dismutase, glutathione peroxidase and catalase activities and a reduction in the level of malondialdehyde were also observed. Histologically, all treatment groups exhibited significant decreases in dysplasia compared to the cancer control group (P<0.05). Immunohistochemical staining demonstrated down-regulation of the PCNA protein. Comparative western blot analysis revealed that COX-2 and Bcl2 were up-regulated and Bax was down-regulated compared with the AOM control group. Conclusion The current study demonstrated that the Cu(BrHAP)2 compound has promising chemoprotective activities that are evidenced by significant decreases in the numbers of ACFs in azoxymethane-induced colon cancer. PMID:24618844

  19. Spectral characterization, optical band gap calculations and DNA binding of some binuclear Schiff-base metal complexes derived from 2-amino-ethanoic acid and acetylacetone

    NASA Astrophysics Data System (ADS)

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

    2015-01-01

    Bi-nuclear metal complexes derived from the reaction of Cu(II), Co(II), Ni(II) and Zn(II) acetates with the Schiff-base ligand (H2L) resulted from the condensation of 2-amino-ethanoic acid (glycine) and acetylacetone have been synthesized and characterized by elemental analyses, Raman spectra, FT-IR, ES-MS, UV-Vis., 1H NMR, ESR, thermal analyses (TG, DTG and DTA) and magnetic measurements. The results showed that, the Schiff base ligand can bind two metal ions in the same time. It coordinates to the first metal ion as mono-negative bi-dentate through azomethine nitrogen and enolic carbonyl after deprotonation. At the same time, it binds to the second metal ion via carboxylate oxygen after deprotonation. The thermodynamic parameters E?, ?H?, ?G? and ?S? have been calculated by Coats-Redfern (CR) and Horowitz-Metzger (HM) methods. The optical band gaps of the isolated complexes have been calculated from absorption spectra and the results indicated semi-conducting nature of the investigated complexes. The interactions between the copper (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.

  20. Spectroscopic Characterization and Biological Activity of Mixed Ligand Complexes of Ni(II) with 1,10-Phenanthroline and Heterocyclic Schiff Bases

    PubMed Central

    Prashanthi, Y.; Kiranmai, K.; Ira; K, Sathish kumar; Chityala, Vijay kumar; Shivaraj

    2012-01-01

    Mixed ligand complexes of Ni(II) with 1,10-phenanthroline (1,10-Phen) and Schiff bases L1(MIIMP); L2(CMIIMP); L3(EMIIMP); L4(MIIMNP); L5(MEMIIMP); L6(BMIIMP); L7(MMIIMP); L8(MIIBD) have been synthesized. These metal chelates have been characterized by elemental analysis, IR, 1H-NMR, 13C-NMR, Mass, UV-Vis, magnetic moments, and thermogravimetric (TG&DTA) analysis. Spectral data showed that the 1,10-phenanthroline act as neutral bidentate ligand coordinating to the metal ion through two nitrogen donor atoms and Schiff bases acts as monobasic bidentate coordinating through NO donor atoms. All Ni(II) complexes appear to have an octahedral geometry. The antimicrobial activity of mixed ligand complexes has been studied by screening against various microorganisms, it is observed that the activity enhances upon coordination. The DNA binding studies have been investigated by UV-Vis spectroscopy, and the experimental results indicate that these complexes bind to CT DNA with the intrinsic binding constant Kb = 2.5 ± 0.2 × 105?M?1. MTT is used to test the anticancer effect of the complexes with HL60 tumor cell. The inhibition ratio was accelerated by increasing the dosage, and it had significant positive correlation with the medication dosage. PMID:23082074

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

    NASA Astrophysics Data System (ADS)

    Emara, Adel A. A.

    2010-09-01

    The binuclear Schiff base, H 2L, ligand was synthesized by reaction of 4,6-diacetylresorcinol with diethylenetriamine in the molar ratio 1:2. The coordination behavior of the H 2L towards Cu(II), Ni(II), Co(II), Zn(II), Fe(III), Cr(III), VO(IV) and UO 2(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 isolated ligand and its metal complexes. The ligand acts as dibasic with two N 3O-tetradentate sites and can coordinate with two metal ions to form binuclear complexes. The bonding sites are the nitrogen atoms of the azomethine and amine groups and the oxygen atoms of the phenolic groups. The metal complexes exhibit either square planar, tetrahedral, square pyramid or octahedral structures. The Schiff base ligand and its metal complexes were tested against four pathogenic bacteria ( Staphylococcus aureus and Streptococcus pyogenes) as Gram-positive bacteria, and ( Pseudomonas fluorescens and Pseudomonas phaseolicola) as Gram-negative bacteria and two pathogenic fungi ( Fusarium oxysporum and Aspergillus fumigatus) to assess their antimicrobial properties. Most of the complexes exhibit mild antibacterial and antifungal activities against these organisms.

  2. 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

  3. Heterobinuclear Zn-Ln (Ln?=?La, Nd, Eu, Gd, Tb, Er and Yb) complexes based on asymmetric Schiff-base ligand: synthesis, characterization and photophysical properties.

    PubMed

    Zhao, Shunsheng; Liu, Xiangrong; Lü, Xingqiang; Wong, Wai-Kwok

    2013-01-01

    With a novel asymmetric Schiff-base zinc complex ZnL (H2 L?=?N-(3-methoxysalicylidene)-N'-(5-bromo-3-methoxysalicylidene)phenylene-1,2-diamine), obtained from phenylene-1,2-diamine, 3-methoxysalicylaldehyde and 5-bromo-3-methoxysalicylaldehyde, as the precursor, a series of heterobinuclear Zn-Ln complexes [ZnLnL(NO3 )3 (CH3 CN)] (Ln?=?La, 1; Ln?=?Nd, 2; Ln?=?Eu, 3; Ln?=?Gd, 4; Ln?=?Tb, 5; Ln?=?Er, 6; Ln?=?Yb, 7) were synthesized by the further reaction with Ln(NO3 )3 ·6H2 O, and characterized by Fourier transform-infrared, fast atom bombardment mass spectroscopy and elemental analysis. Photophysical studies of these complexes show that the strong and characteristic near-infrared luminescence of Nd(3+) , Yb(3+) and Er(3+) with emissive lifetimes in the microsecond range has been sensitized from the excited state of the asymmetric Schiff-base ligand due to effective intramolecular energy transfer; the other complexes do not show characteristic emission due to the energy gap between the chromophore and lanthanide ions. PMID:23001932

  4. An unexpected Schiff base-type Ni(II) complex: synthesis, crystal structures, fluorescence, electrochemical property and SOD-like activities.

    PubMed

    Chai, Lan-Qin; Zhang, Hong-Song; Huang, Jiao-Jiao; Zhang, Yu-Li

    2015-02-25

    An unexpected Schiff base-type Ni(II) complex, [Ni(L(2))2]?CH3OH (HL(2) = 1-(2-{[(E)-3, 5-dibromo-2-hydroxybenzylidene]amino}phenyl)ethanone oxime), has been synthesized via complexation of Ni(II) acetate tetrahydrate with HL(1) (2-(3,5-dibromo-2-hydroxyphenyl)-4-methyl-1,2-dihydroquinazoline 3-oxide) originally. HL(1) and its corresponding Ni(II) complex were characterized by IR, (1)H NMR spectra, as well as by elemental analysis, UV-Vis and emission spectroscopy, respectively. Crystal structures of the ligand and complex have been determined by single-crystal X-ray diffraction. Each complex links two other molecules into an infinite 1-D chain via intermolecular hydrogen bonding interactions. Moreover, the electrochemical property of the nickle complex was studied by cyclic voltammetry. In addition, SOD-like activities of HL(1) and Ni(II) complex were also investigated. PMID:25247838

  5. Synthesis, spectroscopic and biological activities studies of acyclic and macrocyclic mono and binuclear metal complexes containing a hard-soft Schiff base

    NASA Astrophysics Data System (ADS)

    Abou-Hussein, Azza A. A.; Linert, Wolfgang

    Mono- and bi-nuclear acyclic and macrocyclic complexes with hard-soft Schiff base, H2L, ligand derived from the reaction of 4,6-diacetylresorcinol and thiocabohydrazide, in the molar ratio 1:2 have been prepared. The H2L ligand reacts with Co(II), Ni(II), Cu(II), Zn(II), Mn(II) and UO2(VI) nitrates, VO(IV) sulfate and Ru(III) chloride to get acyclic binuclear complexes except for VO(IV) and Ru(III) which gave acyclic mono-nuclear complexes. Reaction of the acyclic mono-nuclear VO(IV) and Ru(III) complexes with 4,6-diacetylresorcinol afforded the corresponding macrocyclic mono-nuclear VO(IV) and Ru(IIII) complexes. Template reactions of the 4,6-diacetylresorcinol and thiocarbohydrazide with either VO(IV) or Ru(III) salts afforded the macrocyclic binuclear VO(IV) and Ru(III) complexes. The Schiff base, H2L, ligand acts as dibasic with two NSO-tridentate sites and can coordinate with two metal ions to form binuclear complexes after the deprotonation of the hydrogen atoms of the phenolic groups in all the complexes, except in the case of the acyclic mononuclear Ru(III) and VO(IV) complexes, where the Schiff base behaves as neutral tetradentate chelate with N2S2 donor atoms. The ligands and the metal complexes were characterized by elemental analysis, IR, UV-vis 1H-NMR, thermal gravimetric analysis (TGA) and ESR, as well as the measurements of conductivity and magnetic moments at room temperature. Electronic spectra and magnetic moments of the complexes indicate the geometries of the metal centers are either tetrahedral, square planar or octahedral. Kinetic and thermodynamic parameters were calculated using Coats-Redfern equation, for the different thermal decomposition steps of the complexes. The ligands and the metal complexes were screened for their antimicrobial activity against Staphylococcus aureus as Gram-positive bacteria, and Pseudomonas fluorescens as Gram-negative bacteria in addition to Fusarium oxysporum fungus. Most of the complexes exhibit mild antibacterial and antifungal activities against these organisms.

  6. 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

  7. 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

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

    NASA Astrophysics Data System (ADS)

    Ali, Omyma A. M.

    2014-11-01

    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.

  9. Synthesis, spectroscopy and biological investigations of manganese(III) Schiff base complexes derived from heterocyclic ?-diketone with various primary amine and 2,2'-bipyridyl

    NASA Astrophysics Data System (ADS)

    Surati, Kiran R.

    2011-06-01

    The mixed ligand mononuclear complex [Mn(bipy)(HPMFP)(OAc)]ClO 4 was synthesized by reaction of Mn(OAc) 3·2H 2O with HPMFP and 2,2'-bipyridyl. The corresponding Schiff base complexes were prepared by condensation of [Mn(bipy)(HPMFP)(OAc)]ClO 4 with ethylenediamine, ethanolamine and glycine (where HPMFP = 1-phenyl-3methyl-4-formyl-2-pyrazolin-5one, bipy = 2,2'-bipyridyl). All the compounds have been characterized by elemental analysis, magnetic susceptibility, conductometry measurements and 1H and 13C NMR, FT-IR, mass spectrometry. Electronic spectral and magnetic susceptibility measurements indicate square pyramidal geometry around manganese(III) ion. The thermal stabilities, activation energy E*, entropy change ? S*, enthalpy change ? H* and heat capacity of thermal degradation for these complexes were determined by TGA and DSC. The in vitro antibacterial and antifungal activity of four coordination compounds and ligand HPMFP were investigated. In vitro activates of Bacillus subtillis (MTCC-619), Staphylococcus aureus (MTCC-96), Escherichia coli (MTCC-722) and Klebsiella pneumonia (MTCC-109) bacteria and the fungus Candida albicans (ATCC-90028) were determined. All the compounds showed good antimicrobial activity. The antimicrobial activities increased as formation of Schiff base.

  10. 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).

    PubMed

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

    2014-09-15

    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. PMID:24813293

  11. 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.

  12. Synthesis, solvatochromaticity and bioactivities of some transition metal complexes with 2-(R-benzylideneamino)-pyridin-3-ol Schiff base derivatives

    NASA Astrophysics Data System (ADS)

    Ahmed, I. S.; Kassem, M. A.

    2010-10-01

    New four Schiff bases are prepared by condensation of 2-amino-pyridin-3-ol with 3, 4-dihydroxy-benzaldehyde (I), 2-hydroxybenzaldehyde (II), 5-bromo-2-hydroxybenzaldehyde (III), and 4-dimethylaminobenzaldehyde (IV). The structures of these compounds are characterized based on elemental analyses (C. H. N), IR and 1H NMR. Also, the electronic absorption spectra are recorded in organic solvents of different polarity. The solvents are selected to be covered a wide range of parameters (refractive index, dielectric constant and hydrogen bonding capacity). The UV-vis absorption spectra of Schiff base compounds are investigated in aqueous buffer solutions of varying pH and utilized for the determination of ionization constant, p Ka and activation free energy, ? G* of the ionization process. The biological activity against bacterial species and fungi as microorganisms representing different microbial categories such as (two Gram-negative bacteria, Eschericha coli and Agrobacterium sp.),three Gram-positive bacteria ( Staphylococcus aureus, Bacillus subtlus and Bacillus megatherium), yeast ( Candida albicans), and fungi ( Aspergillus niger) were studied.

  13. Solid state 15N and 13C NMR study of dioxomolybdenum (VI) complexes of Schiff bases derived from trans-1,2-cyclohexanediamine

    NASA Astrophysics Data System (ADS)

    Schilf, W.; Kamie?ski, B.; Rozwadowski, Z.; Ambroziak, K.; Bieg, B.; Dziembowska, T.

    2004-08-01

    The 13C, 15N CP MAS NMR and FT-IR spectra of dioxomolybdenum (VI) complexes of trans- N, N'-bis-(R-salicylidene)-1,2-cyclohexanediamine (R=H, R=3,5-diCl, R=3,5-diBr, R=4,6-diOCH 3), trans- N, N'-bis-(2-OH-naphthylidene)-1,2-cyclohexanediamine and trans- N-(salicylidene)- N'-(2-OH-naphthylidene)-1,2-cyclohexanediamine have been measured. Comparative analysis of the NMR and IR spectra of the complexes with those of the corresponding ligands has shown that the complexation of the di-Schiff bases leads to changes in the conformation of the ligands and the charge redistribution. The asymmetric structure and non-planar structure of the complexes have been suggested.

  14. 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.

  15. Antibacterial Role of SO42-, NO3-, C2O42- and CH3CO2- Anions on Cu(II) and Zn(II) Complexes of a Thiadiazole-derived Pyrrolyl Schiff Base

    PubMed Central

    Pervez, Humayun; Rauf, Abdul; Supuran, Claudiu T.

    2002-01-01

    A condensation reaction of 2-amino-1,3,4-thiadiazole with 2-pyrrolecarboxaldehyde to form tridentate NNN donor Schiff base has been performed. The prepared Schiff base was further used for the formation of metal complexes having stoichiometry [M(L)2]Xn, where M=Cu(II) or Zn(II), L=N-(2-pyrrolylmethylene)-2-amino-1,3,4-thiadiazole, X=SO42?, NO3?, C2O42? or CH3CO2? and n=1 or 2. The new compounds described here have been characterized by their physical, spectral and analytical data, and have been screened against several bacterial strains such as Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa. The antibacterial potency of the Schiff base increased upon chelation/complexation, having the same metal ion (cation) but different anions opening up a novel approach in finding new ways to fight against antibiotic resistant strains. PMID:18476004

  16. 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.

  17. Synthesis and characterization of complexes of UO 2 (II) and Th(IV) of bis-schiff bases derived from furoylpyrazolone

    Microsoft Academic Search

    G. X. Zheng; Q. F. Wang; S. G. Luo

    2003-01-01

    Four new complexes of UO2(II) and Th(IV) with bis-Schiff bases, derived from N,N'-bis[(l-phenyl-3-methyl-5-oxo-4-pyrazolinyl)-a-furylmethylidyne]-1,2-propylenediimine [1,2-BPMOPFP-H2] and N,N'- bis[(l-phenyl-3-methyl-5-oxo-4-pyrazolinyl)-a-furylmethylidyne]-1,3-propylenediimine [1,3-BPMOPFP-H2], were synthesized and characterized by elemental analysis, IR, UV, 1HNMR spectroscopy, and molar conductivity. The general formula of the complexes was confirmed to be [UO2(BPMOPFP)], [Th(BPMOPFP)(NO3)]NO3. A possible structure for the complexes have been proposed.

  18. Synthesis, spectroscopic studies, antimicrobial activities and antitumor of a new monodentate V-shaped Schiff base and its transition metal complexes

    NASA Astrophysics Data System (ADS)

    Ramadan, Ramadan M.; Abu Al-Nasr, Ahmad K.; Noureldeen, Amani F. H.

    2014-11-01

    Reaction of 4-aminoacetophenone and 4-bromobenzaldehyde in ethanol resulted in the formation of the monodentate V-shaped Schiff base (E)-1-(4-((4-bromo-benzylidene)amino)phenyl)ethanone (L). Interaction of L with different di- and trivalent metal ions revealed disubstituted derivatives. The ligand and its complexes were characterized by elemental analysis, mass, IR and NMR spectrometry. Biological activities of the ligand and complexes against the Escherchia coli and Staphylococcus aureus bacterias, and the two fungus Aspergillus flavus and Candida albicans were screened. The cytotoxicity of the compounds were checked as antitumor agents on liver carcinoma cell line (HepG2). They exhibited in vitro broad range of antitumor activities towards the cell line; the [ZnL2(H2O)2](NO3)2 complex was stronger antitumor towards HepG2 cell line as well as two breast cancer cell lines (MCF7 and T47D) relative to cis-platin.

  19. Synthesis, characterization, equilibrium study and biological activity of Cu(II), Ni(II) and Co(II) complexes of polydentate Schiff base ligand

    NASA Astrophysics Data System (ADS)

    El-Sherif, Ahmed A.; Shehata, Mohamed R.; Shoukry, Mohamed M.; Barakat, Mohammad H.

    2012-10-01

    Schiff base ligand, 1,4-bis[(2-hydroxybenzaldehyde)propyl]piperazine (BHPP), and its Cu(II), Ni(II) and Co(II) metal complexes were synthesized and characterized by elemental analysis, magnetic susceptibility, molar conductance and spectral (IR and UV-vis) studies. The ground state of BHPP ligand was investigated using the BUILDER module of MOE. Metal complexes are formed in the 1:1 (M:L) ratio as found from the elemental analysis and found to have the general formula [ML]·nH2O, where M = Co(II), Ni(II) and Cu(II), L = BHPP. In all the studied complexes, the (BHPP) ligand behaves as a hexadentate divalent anion with coordination involving the two azomethine nitrogen's, the two nitrogen atoms of piperazine ring and the two deprotonated phenolic OH-groups. The magnetic and spectral data indicates octahedral geometry of metal(II) complexes. The ligand and their metal chelates have been screened for their antimicrobial activities using the disc diffusion method against the selected bacteria and fungi. They were found to be more active against Gram-positive than Gram-negative bacteria. Protonation constants of (BHPP) ligand and stability constants of its Cu2+, Co2+ and Ni2+ complexes were determined by potentiometric titration method in 50% DMSO-water solution at ionic strength of 0.1 M sodium nitrate. It has been observed that the protonated Schiff base ligand (BHPP) have four protonation constants. The divalent metal ions Cu2+, Ni2+ and Co2+ form 1:1 complexes.

  20. Synthesis, characterization, equilibrium study and biological activity of Cu(II), Ni(II) and Co(II) complexes of polydentate Schiff base ligand.

    PubMed

    El-Sherif, Ahmed A; Shehata, Mohamed R; Shoukry, Mohamed M; Barakat, Mohammad H

    2012-10-01

    Schiff base ligand, 1,4-bis[(2-hydroxybenzaldehyde)propyl]piperazine (BHPP), and its Cu(II), Ni(II) and Co(II) metal complexes were synthesized and characterized by elemental analysis, magnetic susceptibility, molar conductance and spectral (IR and UV-vis) studies. The ground state of BHPP ligand was investigated using the BUILDER module of MOE. Metal complexes are formed in the 1:1 (M:L) ratio as found from the elemental analysis and found to have the general formula [ML]·nH(2)O, where M=Co(II), Ni(II) and Cu(II), L=BHPP. In all the studied complexes, the (BHPP) ligand behaves as a hexadentate divalent anion with coordination involving the two azomethine nitrogen's, the two nitrogen atoms of piperazine ring and the two deprotonated phenolic OH-groups. The magnetic and spectral data indicates octahedral geometry of metal(II) complexes. The ligand and their metal chelates have been screened for their antimicrobial activities using the disc diffusion method against the selected bacteria and fungi. They were found to be more active against Gram-positive than Gram-negative bacteria. Protonation constants of (BHPP) ligand and stability constants of its Cu(2+), Co(2+) and Ni(2+) complexes were determined by potentiometric titration method in 50% DMSO-water solution at ionic strength of 0.1 M sodium nitrate. It has been observed that the protonated Schiff base ligand (BHPP) have four protonation constants. The divalent metal ions Cu(2+), Ni(2+) and Co(2+) form 1:1 complexes. PMID:22935596

  1. Synthesis, spectroscopy and thermal study of some nickel(II) complexes containing tridentate Schiff bases and substituted amine ligands, X-ray crystal structure of nickel(II) complex.

    PubMed

    Kianfar, Ali Hossein; Bahramian, Masomeh; Khavasi, Hamid Reza

    2012-08-01

    Some new tridentate ONO and ONS Schiff base complexes of [NiL(amine)] (L=Salicylidene2-aminophenol and Salicylidene2-aminothiophenol, amine=benzylamine, morpholine, pyrrolidine and piperidine) were synthesized and characterized by IR, UV-vis, (1)H NMR spectroscopy and elemental analysis. The geometry of [NiL(2)(bzlan)] determined by X-ray crystallography indicates that the complex has planar structure and has four coordinate in the solid state. The thermogravimmetry (TG) and differential thermoanalysis (DTA) of the synthesized complexes were carried out in the range of 20-700°C, leading to decomposition of ONO type in two stages and of ONS type in three stages. The ONO and ONS complexes were decomposed to NiO and NiS respectively. Thermal decomposition of the complexes is closely the depends upon nature of the Schiff base ligands and proceeds via first order kinetics. PMID:22525035

  2. Synthesis, spectroscopy and thermal study of some nickel(II) complexes containing tridentate Schiff bases and substituted amine ligands, X-ray crystal structure of nickel(II) complex

    NASA Astrophysics Data System (ADS)

    Kianfar, Ali Hossein; Bahramian, Masomeh; Khavasi, Hamid Reza

    Some new tridentate ONO and ONS Schiff base complexes of [NiL(amine)] (L = Salicylidene2-aminophenol and Salicylidene2-aminothiophenol, amine = benzylamine, morpholine, pyrrolidine and piperidine) were synthesized and characterized by IR, UV-vis, 1H NMR spectroscopy and elemental analysis. The geometry of [NiL2(bzlan)] determined by X-ray crystallography indicates that the complex has planar structure and has four coordinate in the solid state. The thermogravimmetry (TG) and differential thermoanalysis (DTA) of the synthesized complexes were carried out in the range of 20-700 °C, leading to decomposition of ONO type in two stages and of ONS type in three stages. The ONO and ONS complexes were decomposed to NiO and NiS respectively. Thermal decomposition of the complexes is closely the depends upon nature of the Schiff base ligands and proceeds via first order kinetics.

  3. Nickel (II) and Copper (II) Complexes Derived from NNOS Donor Unsymmetrical Tetradentate Schiff Base Ligands: Synthesis, Characterization, and Thermodynamic Studies

    Microsoft Academic Search

    Mozaffar Asadi; Sheida Esmaielzadeh; Khosro Mohammadi

    2010-01-01

    A set of eight unsymmetrical tetradentate Schiff bases (cdPhsalpd = Methyl-2-{[3-(2-hydroxyphenyl)phenylidynenitrilo]propyl}amino-1-cyclopentenedithiocarboxylate; cd3-, 4-, 5-OMesalpd = Methyl-2-{[3-(2-hydroxy 3-, 4-, 5-methoxyphenyl)methylidynenitrilo]propyl} amino-1-cyclopentenedithiocarboxylate; cd5Clsalen = Methyl-2-{[3-(2-hydroxy-5-chloro phenyl)methylidynenitrilo]propyl}amino-1-cyclopentenedithiocarboxylate; cd5Brsalen = Methyl-2-{[3-(2-hydroxy-5-bromophenyl)methylidynenitrilo]propyl}amino- 1-cyclopente- nedithiocarboxylate; cd5NO2salen = Methyl-2-{[3-(2-hydroxy-5-nitrophenyl)methylidyne- nitrilo]propyl}amino-1-cyclopentenedithiocarboxylate; and cd5SO3Na = Methyl-2-{[3- (2-hydroxy-5-sodiumsulfitephenyl)methylidynenitrilo]propyl} amino-1-cyclopentenedithi- ocarboxylate, have been obtained by condensation of methyl-2-(3-aminopropylamino) cyclopentenedithiocarboxylate (Hcdpd) with some substituted salicylaldehydes, 2-hydroxy acetophenone, and 2-hydroxy benzophenone, which present

  4. 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

  5. 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.

  6. Synthesis, spectral and antimicrobial activity of Zn(II) complexes with Schiff bases derived from 2-hydrazino-5-[substituted phenyl]-1,3,4-thiadiazole and benzaldehyde/2-hydroxyacetophenone/indoline-2,3-dione

    NASA Astrophysics Data System (ADS)

    Singh, Ajay K.; Pandey, O. P.; Sengupta, S. K.

    2013-09-01

    Zn(II) complexes have been synthesized by reacting zinc acetate with Schiff bases derived from 2-hydrazino-5-[substituted phenyl]-1,3,4-thiadiazole and 2-hydroxyacetophenone/benzaldehyde/indoline-2,3-dione. All these complexes are soluble in DMF and DMSO; low molar conductance values indicate that they are non electrolytes. Elemental analyses suggest that the complexes have 1:2 metal to ligands stoichiometry of the types [ZnL2(H2O)2](L = monoanionic Schiff bases derived from 2-hydrazino-5-[substituted phenyl]-1,3,4-thiadiazole and 2-hydroxyacetophenone/indoline-2,3-dione) [ZnL2?(OOCCH3)2(H2O)2](L? = neutral Schiff bases derived from 2-hydrazino-5-[substituted phenyl]-1,3,4-thiadiazole and benzaldehyde), and they were characterized by IR, 1H NMR, and 13C NMR. Particle sizes of synthesized compounds were measured with dynamic light scattering (DLS) analyser which indicates that particle diameter are of the range ca. 100-200 nm. All these Schiff bases and their complexes have also been screened for their antibacterial (Bacillus subtilis (B. subtilis), Escherichia coli (E. coli) and antifungal activities (Colletotrichum falcatum (C. falcatum), Aspergillus niger (A. niger), Fusarium oxysporium (F. oxysporium) Curvularia pallescence (C. pallescence). The antimicrobial activities have shown that upon complexation the activity increases.

  7. Synthesis, characterization and thermal studies of dinuclear adducts of diorganotin(IV) dichlorides with nickel(II) Schiff-base complexes in chloroform

    Microsoft Academic Search

    Khosrow Aein Jamshid; Mozaffar Asadi; Ali Hossein Kianfar

    2009-01-01

    The formation constants and free energies for the interaction of R2SnCl2 (R = methyl, n-butyl, phenyl) as acceptors, with nickel Schiff-base complexes, ([NiL]) where L = Salen [N,N?-bis(salicylaldehydo)ethylenediimine] (1), 7,7?-Me2Salen [N,N?-bis(2-hydroxyacetophenone) ethylenediimine] (2), Salpn [N,N?-bis(salicylaldehydo)-1,3-propanediimine] (3), Salophen [N,N?-bis(salicylaldehydo)-1,2-phenylenediimine] (4) as donors and also the interaction of Ph2SnCl2 with [NiL?], where L? = [5-methoxysalen, N,N?-bis(5-methoxysalicylidene)ethylenediimine] (5), [5-methoxysalophen, N,N?-bis(5-methoxysalicylidene)-1,2-phenylenediimine] (6) and [5-chlorosalen,

  8. Immobilized molybdenum-thiosemicarbazide Schiff base complex on the surface of magnetite nanoparticles as a new nanocatalyst for the epoxidation of olefins

    NASA Astrophysics Data System (ADS)

    Mohammadikish, M.; Masteri-Farahani, M.; Mahdavi, S.

    2014-03-01

    In this work, a new magnetically recoverable nanocatalyst was developed by immobilization of thiosemicarbazide ligand on the surface of silica coated magnetite nanoparticles (SCMNPs) through Schiff base condensation and followed complexation with MoO2(acac)2. Characterization of the prepared nanocatalyst was performed with different physicochemical methods such as Fourier transform infrared (FT-IR) and atomic absorption spectroscopies, X-ray diffraction (XRD), vibrating sample magnetometry (VSM), thermogravimetric analysis (TGA), field-emission scanning electron microscopy (FE-SEM), and transmission electron microscopy (TEM). The prepared catalyst catalyzed the epoxidation of olefins and allyl alcohols with tert-butyl hydroperoxide (TBHP) and cumene hydroperoxide (CHP) quantitatively with excellent selectivity toward the corresponding epoxides under mild reaction conditions.

  9. Structurally Diverse Copper(II) Complexes of Polyaza Ligands Containing 1,2,3-Triazoles: Site Selectivity and Magnetic Properties

    E-print Network

    Weston, Ken

    Structurally Diverse Copper(II) Complexes of Polyaza Ligands Containing 1,2,3-Triazoles: Site, Florida 32306-4390, United States *S Supporting Information ABSTRACT: Copper(II) acetate mediated coupling, was observed in the copper(II) complexes of L1 -L6 . The preference of copper(II) to two common bidentate 1

  10. Synthesis, characterization, crystal structure and predicting the second-order optical nonlinearity of a new dicobalt(III) complex with Schiff base ligand

    NASA Astrophysics Data System (ADS)

    Zarei, Seyed Amir; Piltan, Mohammad; Hassanzadeh, Keyumars; Akhtari, Keivan; Cin?i?, Dominik

    2015-03-01

    The synthesis and characterization of dicobalt(III) complex [Co2L2(OMe)2] of the tetradentate Schiff base ligand N,N?-bis(2-hydroxybenzylidene)-2,2-dimethyl-1,3-propanediamine (H2L) is reported. The crystal structure of the complex has been determined that exhibited the pseudo-octahedral geometry around both cobalt(III) ions. In the complexation process, H2L acts as two negatively charged tetradentate ligand, L2-, and methoxy group plays as bridging ligand. The geometry structure of the complex is optimized by density functional theory (DFT) using B3LYP/6-311G(d,p). The calculated geometric parameters are in good agreement with the corresponding experimental data. Second-Order Nonlinear Optical (NLO) property of the complex is evaluated by DFT/B3LYP/6-311G(d,p) on the base of the optimized structure that shows the enhancement relative to the calculated value of H2L. The calculated NLO value of the complex is much greater than the corresponding value of urea.

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

    PubMed

    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. PMID:25748987

  12. Copper(II) complexes of rat amylin fragments.

    PubMed

    Kállay, Csilla; Dávid, Agnes; Timári, Sarolta; Nagy, Eszter Márta; Sanna, Daniele; Garribba, Eugenio; Micera, Giovanni; De Bona, Paolo; Pappalardo, Giuseppe; Rizzarelli, Enrico; Sóvágó, Imre

    2011-10-14

    The fragments of rat amylin rIAPP(17-29) (Ac-VRSSNNLGPVLPP-NH(2)), rIAPP(17-22) (Ac-VRSSNN-NH(2)), rIAPP(19-22) (Ac-SSNN-NH(2)) and rIAPP(17-20) (Ac-VRSS-NH(2)) together with the related mutant peptides (Ac-VASS-NH(2) and Ac-VRAA-NH(2)) have been synthesized and their copper(II) complexes studied by potentiometric, UV-Vis, CD and EPR spectroscopic methods. Despite the lack of any common strongly coordinating donor functions some of these fragments are able to bind copper(II) ions in the physiological pH range. The longest fragment rat amylin(17-29) keeps one equivalent copper(II) ion in solution in the whole pH range, while two other peptides Ac-VRSSNN-NH(2) and Ac-SSNN-NH(2) are also able to interact with copper(II) ions in the slightly alkaline pH range. According to the spectral parameters of the complexes, the peptides can be classified into two different categories: (i) the tetrapeptides Ac-VRSS-NH(2), Ac-VASS-NH(2) and Ac-VRAA-NH(2) can interact with copper(II) only under strongly alkaline conditions (pH > 10.0) and the formation of only one species with four amide nitrogen coordination can be detected; (ii) the peptides Ac-VRSSNNLGPVLPP-NH(2), Ac-VRSSNN-NH(2) and Ac-SSNN-NH(2) can form complexes above pH 6.0 with the major stoichiometries [CuH(-2)L], [CuH(-3)L](-) and [CuH(-4)L](2-). These data support that rIAPP(17-29) can interact with copper(II) ions under physiological conditions and the SSNN tetrapeptide fragment can be considered as the shortest sequence responsible for metal binding. Density functional theory (DFT) calculations provide some information on the possible coordination modes of Ac-SSNN-NH(2) towards the copper(II) ion and suggest that for [CuH(-2)L], [CuH(-3)L](-) and [CuH(-4)L](2-), the binding of two, three and four deprotonated amide nitrogens, with NH(-) of the side chain of asparagine as anchoring group, is probable. Moreover, these data reveal that peptides can be effective metal binding ligands even in the absence of anchoring groups, if more polar side chains are present in a specific sequence. PMID:21858342

  13. Copper(II) acetate and picrate complexes of sulfa drugs

    Microsoft Academic Search

    Krishna K. Narang; Jai K. Gupta

    1977-01-01

    Summary Copper(II) acetate and picrate complexes of sulfa drugsviz., sulfanilamide, sulfaguanidine, sulfathiazole, sulfadiazine, sulfamerazine and sulfamethazine were prepared and characterized with the help of analytical, electronic, i.r. and magnetic moment data. The complexes are paramagnetic, planar or mixed planar and octahedral, insoluble and melt (with decomposition) in the 185°–225° range. The sulfa drugs coordinate through their amino groups and the

  14. DNA cleavage, antibacterial, antifungal and anthelmintic studies of Co(II), Ni(II) and Cu(II) complexes of coumarin Schiff bases: synthesis and spectral approach.

    PubMed

    Patil, Sangamesh A; Prabhakara, Chetan T; Halasangi, Bhimashankar M; Toragalmath, Shivakumar S; Badami, Prema S

    2015-02-25

    The metal complexes of Co(II), Ni(II) and Cu(II) have been synthesized from 6-formyl-7,8-dihydroxy-4-methylcoumarin with o-toluidine/3-aminobenzotrifluoride. The synthesized Schiff bases and their 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 molar conductance values indicate that complexes are non-electrolytic in nature. Elemental analysis reveals ML2·2H2O [M = Co(II), Ni(II) and Cu(II)] stoichiometry, where 'L' stands for a singly deprotonated ligand. The presence of co-ordinated water molecules were confirmed by thermal studies. The spectroscopic studies suggest the octahedral geometry. Redox behavior of the complexes were confirmed by cyclic voltammetry. All the synthesized compounds were screened for their antibacterial (Escherichia coli, Pseudomonas auregenosa, klebsiella, Proteus, Staphylococcus aureus and salmonella) antifungal (Candida, Aspergillus niger and Rhizopus), anthelmintic (Pheretima posthuma) and DNA cleavage (Calf Thymus DNA) activity. PMID:25244297

  15. DNA cleavage, antibacterial, antifungal and anthelmintic studies of Co(II), Ni(II) and Cu(II) complexes of coumarin Schiff bases: Synthesis and spectral approach

    NASA Astrophysics Data System (ADS)

    Patil, Sangamesh A.; Prabhakara, Chetan T.; Halasangi, Bhimashankar M.; Toragalmath, Shivakumar S.; Badami, Prema S.

    2015-02-01

    The metal complexes of Co(II), Ni(II) and Cu(II) have been synthesized from 6-formyl-7,8-dihydroxy-4-methylcoumarin with o-toluidine/3-aminobenzotrifluoride. The synthesized Schiff bases and their metal complexes were structurally characterized based on IR, 1H NMR, 13C NMR, UV-visible, ESR, magnetic, thermal, fluorescence, mass and ESI-MS studies. The molar conductance values indicate that complexes are non-electrolytic in nature. Elemental analysis reveals ML2·2H2O [M = Co(II), Ni(II) and Cu(II)] stoichiometry, where 'L' stands for a singly deprotonated ligand. The presence of co-ordinated water molecules were confirmed by thermal studies. The spectroscopic studies suggest the octahedral geometry. Redox behavior of the complexes were confirmed by cyclic voltammetry. All the synthesized compounds were screened for their antibacterial (Escherichia coli, Pseudomonas auregenosa, klebsiella, Proteus, Staphylococcus aureus and salmonella) antifungal (Candida, Aspergillus niger and Rhizopus), anthelmintic (Pheretima posthuma) and DNA cleavage (Calf Thymus DNA) activity.

  16. Effect of structure and composition of nickel(II) complexes with salicylidene Schiff base ligands on their DNA/protein interaction and cytotoxicity.

    PubMed

    Li, Peng; Niu, MeiJu; Hong, Min; Cheng, Shuang; Dou, JianMin

    2014-08-01

    Three new salicylidene Schiff base nickel(II) complexes [Ni(L(1))(CH3COOH)2]2 (1), [Ni2(L(1))2(CH3OH)] (2), [Ni(L(2))2]·3H2O (3) {H2L(1)=N,N'-bis(salicylidene)-3,6-dioxa-1,8-diaminooctane, HL(2)=2-ethyl-2-(2-hydroxybenzylideneamino)propane-1,3-diol} were synthesized and characterized fully by structural, analytical, and spectral methods. The single-crystal X-ray structures of complexes 1 and 2 exhibit the symmetrical ligands coordinated to the nickel(II) ion in a tetradentate fashion via ONNO donor atoms, while the unsymmetrical ligand L(2) presented a ONO tridentate coordination mode in complex 3. The nickel(II) ions lie in the six-coordinated octahedral environment for the mononuclear complexes 1 and 3, along with dinuclear complex 2. The interaction of the complexes with calf thymus DNA (CT-DNA) has been explored by absorption and emission titration methods, which revealed that complexes 1-3 could interact with CT-DNA through intercalation. The interactions of the complexes with bovine serum albumin (BSA) were also investigated using UV-Vis, fluorescence and synchronous fluorescence spectroscopic methods. The results indicated that all of the complexes could quench the intrinsic fluorescence of BSA in a static quenching process. Further, the in vitro cytotoxic effect of the complexes examined on cancerous cell lines such as human lung carcinoma cell line (A549), human colon carcinoma cell lines (HCT-116), human promyelocytic leukemia cells (HL-60) and colonic cancer cell line Caco-2 showed that all three complexes exhibited substantial cytotoxic activity. PMID:24838006

  17. Synthesis and Characterisation of Copper(II) Complexes with Tridentate NNO Functionalized Ligand: Density Function Theory Study, DNA Binding Mechanism, Optical Properties, and Biological Application

    PubMed Central

    Hazra, Madhumita; Dolai, Tanushree; Pandey, Akhil; Dey, Subrata Kumar; Patra, Animesh

    2014-01-01

    The photo physical properties of two mononuclear pentacoordinated copper(II) complexes formulated as [Cu(L)(Cl)(H2O)] (1) and [Cu(L)(Br)(H2O)] (2) HL?=?(1-[(3-methyl-pyridine-2-ylimino)-methyl]-naphthalen-2-ol) were synthesized and characterized by elemental, physicochemical, and spectroscopic methods. The density function theory calculations are used to investigate the electronic structures and the electronic properties of ligand and complex. The interactions of copper(II) complexes towards calf thymus DNA were examined with the help of absorption, viscosity, and fluorescence spectroscopic techniques at pH 7.40. All spectroscopy's result indicates that complexes show good binding activity to calf thymus DNA through groove binding. The optical absorption and fluorescence emission properties of microwires were characterized by fluorescence microscope. From a spectroscopic viewpoint, all compounds strongly emit green light in the solid state. The microscopy investigation suggested that microwires exhibited optical waveguide behaviour which are applicable as fluorescent nanomaterials and can be used as building blocks for miniaturized photonic devices. Antibacterial study reveals that complexes are better antimicrobial agents than free Schiff base due to bacterial cell penetration by chelation. Moreover, the antioxidant study of the ligand and complexes is evaluated by using 1,1-diphenyl-2-picrylhydrazyl (DPPH) free-radical assays, which demonstrate that the complexes are of higher antioxidant activity than free ligand. PMID:25386109

  18. Interactions of Trivalent Lanthanide Cations with a New Hexadentate Di-Schiff Base: New Lanthanide(III) Complexes from (NE,N?E)-2,2?-(ethane-1,2-diylbis(oxy))bis(N-(pyridin-2-ylmethylene)ethanamine)

    PubMed Central

    Tsiouri, Mantha; Skorda, Konstantina; Papadimitriou, Christos; Li, Yang; Woollins, J. Derek; Plakatouras, John C.

    2010-01-01

    The novel lanthanide(III) complexes [Ln(NO3)2L](NO3)·3MeOH (Ln = La 1, Pr 2) and [Ln(NO3)3L](NO3)·2MeOH (Ln = Gd 3, Yb 4), where L = (NE,N?E)-2,2?-(ethane-1,2-diylbis(oxy))bis(N-(pyridin-2-ylmethylene)ethanamine), 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. Complex 4 was also characterized with crystallographic studies: orthorhombic P212121, a = 10.6683(14), b = 13.4752(15), c = 19.3320(26) Å. In the molecular structure of 4, Yb(III) is surrounded by all donor atoms of the Schiff base (four nitrogen and two oxygen atoms) and four oxygen atoms belonging to two bidentate chelating nitrato ligands. PMID:20689704

  19. Synthesis and DNA binding studies of Ni(II), Co(II), Cu(II) and Zn(II) metal complexes of N 1,N 5-bis[pyridine-2-methylene]-thiocarbohydrazone Schiff-base ligand

    NASA Astrophysics Data System (ADS)

    Tiwari, A. D.; Mishra, A. K.; Mishra, S. B.; Mamba, B. B.; Maji, B.; Bhattacharya, S.

    2011-09-01

    The thiocarbohydrazone Schiff-base ligand with a nitrogen and sulphur donor was synthesized through condensation of pyridine-2-carbaldehyde and thiocarbohydrazide. Schiff-base ligands have the ability to conjugate with metal salts. A series of metal complexes with a general formula [MCl 2(H 2L)]· nH 2O (M dbnd Ni, Co, Cu and Zn) were synthesized by forming complexes of the N 1,N 5-bis[pyridine-2-methylene]-thiocarbohydrazone (H 2L) Schiff-base ligand. These metal complexes and ligand were characterized by using ultraviolet-visible (UV-Vis), Fourier Transform Infrared (FT-IR), 1H and 13C NMR spectroscopy and mass spectroscopy, physicochemical characterization, CHNS and conductivity. The biological activity of the synthesized ligand was investigated by using Escherichia coli DNA as target. The DNA interaction of the synthesized ligand and complexes on E. coli plasmid DNA was investigated in the aqueous medium by UV-Vis spectroscopy and the binding constant ( Kb) was calculated. The DNA binding studies showed that the metal complexes had an improved interaction due to trans-geometrical isomers of the complexes than ligand isomers in cis-positions.

  20. DFT, characterization and investigation of vibrational spectroscopy of 4-(4-hydroxy)-3-(2-pyrazine-2-carbonyl)hydrazonomethylphenyl-diazen-yl-benzenesulfonamide and its copper(II) complex

    NASA Astrophysics Data System (ADS)

    Ammar, Reda A. A.; Alaghaz, Abdel-Nasser M. A.; Elhenawy, Ahmed A.

    2014-06-01

    Azo-Schiff-base complex of Cu(II) has been synthesized and characterized by elemental, spectral and thermal studies. The conductance data indicate the non-electrolytic nature of the complex. The IR spectra of the prepared complex was suggested that the azo-Schiff-base ligand [4-(4-hydroxy)-3-(2-pyrazine-2-carbonyl)hydrazonomethylphenyl-diazen-yl-benzenesulfonamide] (H2L) behaves as a tri-dentate ligand through the carbonyl oxygen atom, azomethine nitrogen atom and phenolic oxygen atom (ONO). The surface morphology (SEM) of the ligand and its copper(II) complex was studied using SEM analysis. X-ray powder diffraction (XRD) helps to determine the cell parameters of the complex. Transmission electron microscopy (TEM) indicated spherical particles of ?200 nm diameter. The physico-chemical studies revealed octahedral geometry around copper ion. The EPR spectra of copper complex in DMSO at 300 and 77 K were recorded and their salient feature was reported. The redox behavior of the ligand and its copper(II) complex were studied using cyclic voltammetry. Thermal properties and decomposition kinetics of copper(II) complex was investigated. The interpretation mathematical analysis and evaluation of kinetic parameters (E, A, ?H, ?S and ?G) of all thermal decomposition stages have been evaluated using Coats-Redfern (CR), Horowitz-Metzger (HM) and Piloyan-Novikova (PN) equations. Moreover, the density functional theory studies are discussed for ligand, using DFT/B3LYP with 6-31G* and 6-311G* level of theory, the absorption spectra has been computed by using time dependent at TD-DFT/B3LYP with 6-31G* and 6-311G* level of theory. The HOMO-LUMO energy gap of studied systems has been discussed.

  1. 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

  2. Synthesis, spectroscopic, antimicrobial and DNA cleavage studies of new Co(II), Ni(II), Cu(II), Cd(II), Zn(II) and Hg(II) complexes with naphthofuran-2-carbohydrazide Schiff base

    NASA Astrophysics Data System (ADS)

    Halli, Madappa B.; Sumathi, R. B.

    2012-08-01

    A series of Co(II), Ni(II), Cu(II), Cd(II), Zn(II) and Hg(II) complexes have been synthesized with newly synthesized Schiff base derived from naphthofuran-2-carbohydrazide and cinnamaldehyde. The elemental analyses of the complexes are confined to the stoichiometry of the type MLCl2 [M = Co(II) and Cu(II)], ML2Cl2 [M = Ni(II), Cd(II), Zn(II) and Hg(II)] respectively, where L is Schiff base ligand. Structures have been proposed from elemental analyses, IR, electronic, mass, 1H NMR, ESR spectral data, magnetic, and thermal studies. The measured low molar conductance values in DMF indicate that the complexes are non-electrolytes. Spectroscopic studies suggest coordination occurs through azomethine nitrogen and carbonyl oxygen of the ligand with the metal ions. The Schiff base and its complexes have been screened for their antibacterial (Escherichia coli, Staphylococcus aureus, Bacillus subtilis and Salmonella typhi) and antifungal (Aspergillus niger, Aspergillus flavus, Cladosporium and Candida albicans) activities by minimum inhibitory concentration (MIC) method. The DNA cleavage studies by agarose gel electrophoresis method was studied for all the complexes.

  3. Spectroscopic, thermal characterization and cytotoxic activity of bi-, tri- and tetra-nuclear Pd(II) and Pt(II) complexes with diSchiff base ligands

    NASA Astrophysics Data System (ADS)

    Hegazy, Wael Hussein

    2014-10-01

    In this paper; new di-, tri-, and tetra-nuclear Pd(II) and Pt(II) complexes of N,N?-bis(3,4-dihydroxybenzylidene)ethan-1,2-diamine (EDH4), N,N?-bis(3,4-dihydroxy-benzylidene)-benzene-1,2-diamine (PDH4) and N,N?-bis-(3,4-dihydroxybenzylidene)-4,5-dimethyl-1,2-diamine (MPDH4) ligands were synthesized by two different methods. The first method involve 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 Pd(II) or Pt(II) ions in the presence of 2,2?-dipyridyl (L) to form the di- and tri-nuclear metal complexes. The second method involve the condensation of the Pd complex LPd(II)L?, (L = 2,2?-dipyridyl, 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 PdCl2 to form di-, tri-, and tetra-nuclear palladium(II) complexes, respectively. Structures of ligands and metal complexes are characterized by physical properties, FT-IR spectra and nuclear magnetic resonance. The geometries of metal complexes are suggested according to elemental analysis, electronic absorption spectra, thermal analysis, atomic absorption, magnetic susceptibility and molar conductance. Cytotoxic activity against lung large cell carcinoma (H460), prostate carcinoma (DU145), breast adenocarcinoma (MCF-7), amelanotic melanoma (M-14), colon adenocarcinoma (HT-29), and chronic myelogenous leukemia (K562) is also reported.

  4. Synthesis and spectroscopic studies of novel mononuclear complexes of cyclic and acyclic Schiff-base derivatives of tridentate and tetradentate coordination with some bivalent transition metal ions

    Microsoft Academic Search

    Akila A. Saleh

    2005-01-01

    Eight novel cyclic and acyclic Schiff-base ligands, L?=?6-amino-3-methyl-1-phenyl-4-aza-3-hepten-1-one, L?=?3,7-diaza-2,4,8-trimethyl-6-phenylnona-3,7-diene-1,9-diamine, L?= 4,7-diaza-3,5,8-trimethyl-1,10-diphenyldeca-3,7-diene-1,10-dione, L?=?3,5,10,14-tetramethyl-7,12-diphenyl-1,4,8,11-tetraazacyclotetradeca-4,7,11,14-tetraene, L?=?7-amino-3-methyl-1-phenyl-4-aza-3-hepten-1-one, L?=?4,8-diaza-5-methyl-7-phenylundeca-4,8-diene-1,11-diamine, L?=?4,8-diaza-3,9-dimethyl-1,11-diphenyldideca-1,11-dione and L?=?2,12-dimethyl-4,10-diphenyl-1,5,9,13-tetraazacyclohexadeca-1,4,9,12-tetraene, have been prepared and characterized by elemental analysis, IR, H NMR and mass spectroscopy. Their corresponding Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) complexes (1–15) have been prepared by the reaction of the ligand with the metal sulfate or chloride in a 1:1 molar

  5. Characterization of Ni(II) complexes of Schiff bases of amino acids and (S)-N-(2-benzoylphenyl)-1- benzylpyrrolidine-2-carboxamide using ion trap and QqTOF electrospray ionization tandem mass spectrometry

    Microsoft Academic Search

    Robert Jir; Michal Hol; Lenka Kol; Milan N ´; Alexander Popkov

    This work demonstrates the application of electrospray ionization mass spectrometry (ESI-MS) using two different mass analyzers, ion trap and hybrid quadrupole time-of-flight (QqTOF) mass analyzer, for the structural characterization of Ni(II) complexes of Schiff bases of (S)-N-(2-benzoylphenyl)-1- benzylpyrrolidine-2-carboxamide with different amino acids. ESI enables the determination of molecular weight on the basis of rather simple positive-ion ESI mass spectra containing

  6. 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

    NASA Astrophysics Data System (ADS)

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

    2013-01-01

    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.

  7. cis-{MoO2}(2+) assisted Mannich-type addition of acetylacetonate methine to the azomethine of tridentate Schiff bases: racemic complexes with chiral transformed ligands.

    PubMed

    Kurapati, Sathish Kumar; Pal, Samudranil

    2015-02-01

    Reactions of [MoO2(acac)2] (acac(-) = acetylacetonate) with the potential N2O-donor 5,5-membered fused chelate rings forming Schiff bases 2-(2-pyridylaldimine)ethanol (HL(1)) and 4/5-R-2-(2-pyridylaldimine)phenols (HL(n); n = 2-5 for R = H, 4-Cl, 4-Me and 5-Me, respectively) lead to the facile formation of racemic complexes of the general formula cis-[MoO2(acacL(1-5))] () in 80-85% yield. Here, (acacL(n))(2-) represents a chiral N2O2-donor ligand system formed by a novel Mannich-type reaction that involves acetylacetonate and the azomethine fragment of HL(n) both coordinated to the cis-{MoO2}(2+) unit. The characterization of has been performed with the help of microanalytical (CHN), spectroscopic (ESI-MS, IR, UV-Vis and (1)H- and (13)C-NMR) and electrochemical measurements. The molecular structures of all the complexes except for are authenticated by single crystal X-ray crystallography. The Mo(vi) center in each of these analogous complexes is in a distorted octahedral N2O4 coordination sphere assembled by the chiral N2O2-donor transformed ligand (acacL(n))(2-) and the two mutually cis-oriented oxo ligands. In the crystal lattice, each of exists as a centrosymmetric discrete dimer via a pair of reciprocal N-HO hydrogen bonds between its enantiomeric pairs. PMID:25554121

  8. 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.

  9. Synthesis and characterisation of nickel Schiff base complexes containing the meso-1,2-diphenylethylenediamine moiety: selective interactions with a tetramolecular DNA quadruplex.

    PubMed

    Davis, Kimberley J; Richardson, Christopher; Beck, Jennifer L; Knowles, Brett M; Guédin, Aurore; Mergny, Jean-Louis; Willis, Anthony C; Ralph, Stephen F

    2015-02-21

    As part of a program of preparing metal complexes which exhibit unique affinities towards different DNA structures, we have synthesised the novel Schiff base complex N,N'-bis-4-(hydroxysalicylidine)meso-diphenylethylenediaminenickel(ii) (), via the reaction of meso-1,2-diphenylethylenediamine and 2,4-dihydroxybenzaldehyde. This compound was subsequently reacted with 1-(2-chloroethyl)piperidine or 1-(2-chloropropyl)piperidine, to afford the alkylated complexes N,N'-bis-(4-((1-(2-ethyl)piperidine)oxy)salicylidine)meso-1,2-diphenylethylenediaminenickel(ii) () and N,N'-bis-(4-((1-(3-propyl)piperidine)oxy)-salicylidine)meso-1,2-diphenylethylenediaminenickel(ii) (), respectively. These complexes were characterised by microanalysis and X-ray crystallography in the solid state, and in solution by (1)H and (13)C NMR spectroscopy. Electrospray ionisation mass spectrometry (ESI-MS) was used to confirm the identity of () and (). The affinities of () and () towards a discrete 16 mer duplex DNA molecule, and examples of both tetramolecular and unimolecular DNA quadruplexes, was explored using a variety of techniques. In addition, the affinity of two other complexes () and (), towards the same DNA molecules was examined. Complexes () and () were prepared by methods analogous to those which afforded () and (), however 1,2-phenylenediamine was used instead of meso-1,2-diphenylethylenediamine in the initial step of the synthetic procedure. The results of ESI-MS and DNA melting temperature measurements suggest that () and () exhibit a lower affinity than () and () towards the 16 mer duplex DNA molecule, while circular dichroism (CD) spectroscopy suggested that none of the four complexes had a major effect on the conformation of the nucleic acid. In contrast, ESI-MS and CD spectroscopy suggested that both () and () show significant binding to a tetramolecular DNA quadruplex. The results of ESI-MS and Fluorescence Resonance Energy Transfer (FRET) assays indicated that () and () did not bind as tightly to a unimolecular DNA quadruplex, although both complexes had a major effect on the CD spectrum of the latter. These results highlight that the presence of the meso-1,2-diphenylethylenediamine moiety in metal complexes of this type may provide a general method for instilling selectivity for some DNA quadruplexes over dsDNA. PMID:25572696

  10. Synthetic and Spectroscopic Characterization of Organotin(IV) Complexes of Biologically Active Schiff Bases Derived from Sulpha Drugs

    PubMed Central

    Gupta, M. K.; Singh, Har Lal; Varshney, S.; Varshney, A. K.

    2003-01-01

    A number of diorganotin(IV) complexes with Schiffbase have been synthesized and characterized by elemental analysis, conductance measurements, molecular weight determinations, infrared, electronic and multinuclear magnetic resonance (1H, 13C and 119Sn NMR) spectral data. The molar conductivity data shows non-electrolytic nature of complexes. The bidentate nature of the ligands is inferred from IR and NMR spectral studies. The antimicrobial activities of the ligands and their tin complexes have been screened in vitro against the organism Escherichia coli; Staphylococus aureus, Prouteus mirabilis, Bacillus thurengiensis, Penicillium co.,sogenum, Aspergillus niger and Fusarium oxysporum. PMID:18365062

  11. Binding Studies of a New Water-Soluble Iron(III) Schiff Base Complex to DNA Using Multispectroscopic Methods

    PubMed Central

    Shahabadi, Nahid; Ghasemian, Zeinab; Hadidi, Saba

    2012-01-01

    A novel iron(III) complex [Fe(SF)](ClO4)3.2H2O; in which SF?=?N,N0-bis{5-[(triphenylphosphonium chloride)-methyl] salicylidene}-o-phenylenediamine) has been synthesized and characterized using different physicochemical methods. The binding of this complex with calf thymus (CT) DNA was investigated by circular dichroism, absorption studies, emission spectroscopy, voltammetric studies, and viscosity measurements. The results showed that this complex can bind to DNA via external and groove binding modes. PMID:22899896

  12. 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.

  13. Mixed Azomethine Mononuclear and Binuclear Copper (II) Complexes with Alkyl and Aryl Schiff Bases Involving ONO and ONS Donor Atoms

    Microsoft Academic Search

    B. V. Patel; Kalpana Desai; B. T. Thaker

    1989-01-01

    Mixed azomethine mononuclear copper (II) complexes of the type [CuLL'] where, L = 1-phenyl-3-methyl-4-benzoylimine-2-pyrazolene-5-ol and L'?acetylacetonimine or benzoylacetonimine or dibenzoylmethanimine or L = acetylacetonimine and L' = benzoylacetonimine or dibenzoylmethanimine or L = benzoylacetonimine and L' = dibenzoylmethanimine have been synthesised by the template method. Binuclear complexes of copper (II) have been synthesised by the reactions of aminoalkanols or aminothiols

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

    PubMed

    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. PMID:25813173

  15. Gastroprotection Studies of Schiff Base Zinc (II) Derivative Complex against Acute Superficial Hemorrhagic Mucosal Lesions in Rats

    PubMed Central

    Golbabapour, Shahram; Gwaram, Nura Suleiman; Hassandarvish, Pouya; Hajrezaie, Maryam; Kamalidehghan, Behnam; Abdulla, Mahmood Ameen; Ali, Hapipah Mohd; Hadi, A. Hamid A; Majid, Nazia Abdul

    2013-01-01

    Background The study was carried out to assess the gastroprotective effect of the zinc (II) complex against ethanol-induced acute hemorrhagic lesions in rats. Methodology/Principal Finding The animals received their respective pre-treatments dissolved in tween 20 (5% v/v), orally. Ethanol (95% v/v) was orally administrated to induce superficial hemorrhagic mucosal lesions. Omeprazole (5.790×10?5 M/kg) was used as a reference medicine. The pre-treatment with the zinc (II) complex (2.181×10?5 and 4.362×10?5 M/kg) protected the gastric mucosa similar to the reference control. They significantly increased the activity levels of nitric oxide, catalase, superoxide dismutase, glutathione and prostaglandin E2, and decreased the level of malondialdehyde. The histology assessments confirmed the protection through remarkable reduction of mucosal lesions and increased the production of gastric mucosa. Immunohistochemistry and western blot analysis indicated that the complex might induced Hsp70 up-regulation and Bax down-regulation. The complex moderately increased the gastroprotectiveness in fine fettle. The acute toxicity approved the non-toxic characteristic of the complex (<87.241×10?5 M/kg). Conclusion/Significance The gastroprotective effect of the zinc (II) complex was mainly through its antioxidant activity, enzymatic stimulation of prostaglandins E2, and up-regulation of Hsp70. The gastric wall mucus was also a remarkable protective mechanism. PMID:24058648

  16. Synthesis and In Vitro Antitumor Activity of Two Mixed-Ligand Oxovanadium(IV) Complexes of Schiff Base and Phenanthroline

    PubMed Central

    Zhang, Yongli; Wang, Xiangsheng; Fang, Wei; Cai, Xiaoyan; Chu, Fujiang; Liao, Xiangwen; Lu, Jiazheng

    2013-01-01

    Two oxovanadium(IV) complexes of [VO(msatsc)(phen)], (1) (msatsc = methoxylsalicylaldehyde thiosemicarbazone, phen = phenanthroline) and its novel derivative [VO (4-chlorosatsc)(phen)], (2) (4-chlorosatsc = 4-chlorosalicylaldehyde thiosemicarbazone), have been synthesized and characterized by elemental analysis, IR, ES-MS, 1H NMR, and magnetic susceptibility measurements. Their antitumor effects on BEL-7402, HUH-7, and HepG2 cells were studied by MTT assay. The antitumor biological mechanism of these two complexes was studied in BEL-7402 cells by cell cycle analysis, Hoechst 33342 staining, Annexin V-FITC/PI assay, and detection of mitochondrial membrane potential (??m). The results showed that the growth of cancer cells was inhibited significantly, and complexes 1 and 2 mainly caused in BEL-7402 cells G0/G1 cell cycle arrest and induced apoptosis. Both 1 and 2 decreased significantly the ??m, causing the depolarization of the mitochondrial membrane. Complex 2 showed greater antitumor efficiency than that of complex 1. PMID:23424390

  17. Biodistribution (as determined by the radiolabelled equivalent) of a gold(III) bis(pyrrolide-imine) Schiff base complex: a potential chemotherapeutic.

    PubMed

    Akerman, Matthew P; Munro, Orde Q; Mongane, Modisenyane; van Staden, Johan A; Rae, William I D; Bester, Cornelius J; Marjanovic-Painter, Biljana; Szucs, Zoltan; Zeevaart, Jan Rijn

    2013-01-01

    The biodistribution of an N2 N2 ' tetradentate gold(III) chelate, which is known to be cytotoxic towards a range of human cancer cell lines, was determined by a radiolabelled equivalent of the compound. The (198) Au-labelled gold(III) chelate of a bis(pyrrolide-imine) Schiff base ligand with a three-carbon di(azomethine) linkage was successfully synthesised with a high radiochemical yield of 73% and radiochemical purity of >95%. The high energy ?-ray emitted by the (198) Au nucleus was used to follow the biodistribution of the compound in vivo in six male Sprague Dawley rats on a gamma camera. The log Po/w value of the (nat) Au analogue, -1.92(2), showed that the compound is hydrophilic and therefore likely to largely remain in the blood pool. This was confirmed by the biodistribution study, which showed 21% of the injected dose (ID) remained in the blood pool 4.5?h after injection. This decreased to 10.8% over a 24-h period. The activity measured in the lungs, 1.48%ID/g, remained relatively constant over a 24-h period suggesting that the complex had accumulated in the lungs in the form of particulates, and could not be cleared by the test subjects. The t½ for the heart and lungs was greater than 24?h. Excretion of the test compound is seemingly via the kidneys, but is slow with approximately 30% of the ID excreted within 24?h. PMID:24285532

  18. Synthesis of tetradentate N 4 Schiff base dioxomolybdenum (VI) complex within MCM-41 as selective catalyst for epoxidation of olefins

    Microsoft Academic Search

    M. Masteri-Farahani; F. Farzaneh; M. Ghandi

    2007-01-01

    Covalent grafting of MCM-41 with 3-chloropropyl trimethoxysilane and subsequent reactions respectively with pypr [N,N?-bis(2-pyrrolmethylidenaminopropyl)amine] and complexation with MoO2(acac)2 afforded MoO2pyprMCM-41. X-ray diffraction and nitrogen sorption analyses revealed the preservation of the textural properties of the support as well as accessibility of the channel system despite sequential reduction in surface area, pore volume and pore size. Elemental analyses showed nearly complete

  19. DNA cleavage, antimicrobial, anti-inflammatory anthelmintic activities, and spectroscopic studies of Co(II), Ni(II), and Cu(II) complexes of biologically potential coumarin Schiff bases

    Microsoft Academic Search

    M. Manjunatha; Vinod H. Naik; Ajaykumar D. Kulkarni; Sangamesh A. Patil

    2011-01-01

    A series of Co(II), Ni(II) and Cu(II) complexes, [ML?·?2H2O] of Schiff bases derived from 4,4-diaminodiphenyl sulfone (dapsone) and 8-formyl-7-hydroxy-4-methylcoumarin\\/5-formyl-6-hydroxycoumarin have been synthesized. From analytical, spectral (IR, NMR, UV-Vis, ESR and FAB mass), and magnetic studies it has been concluded that the metal complexes possess octahedral geometry and are non-electrolytes. The redox behavior of the metal complexes is investigated by cyclic

  20. Multifunctional Composites of Chiral Valine Derivative Schiff Base Cu(II) Complexes and TiO2.

    PubMed

    Takeshita, Yuki; Takakura, Kazuya; Akitsu, Takashiro

    2015-01-01

    We have prepared four new Cu(II) complexes containing valine moieties with imidazole ligands at the fourth coordination sites and examined their photo-induced reactions with TiO2 in order of understanding the reaction mechanisms. Under a nitrogen atmosphere, the intermolecular electron transfer reactions (essentially supramolecular interactions) of these systems, which resulted in the reduction of Cu(II) species to Cu(I) ones, occurred after UV light irradiation. In this study, we have investigated the conditions of the redox reactions in view of substituent effects of aldehyde moieties. The results of cyclic voltammetry (CV) on an rotating ring-disk electrode (RRDE) suggested that the substitution effects and redox potentials were correlated. Density functional theory (DFT) and time-dependent DFT (TD-DFT) calculations were also performed to simulate the UV-Vis and circular dichroism (CD) spectra; the results revealed a reasonably good correlation between the substituent effects and the highest occupied molecular orbitals and the lowest unoccupied molecular orbitals (HOMO-LUMO) gaps associated with the most intense transition bands. In addition, we summarized the substitution effects of Cu(II) complexes for their corresponding UV light-induced reactions. PMID:25686033

  1. Mechanochemical Reaction of Polymeric Oxovanadium(IV) Complexes with Schiff Base Ligands Derived from 5-Nitrosalicylaldehyde and Diamines

    NASA Astrophysics Data System (ADS)

    Tsuchimoto, Masanobu; Hoshina, Gakuse; Yoshioka, Naoki; Inoue, Hidenari; Nakajima, Kiyohiko; Kamishima, Mayumi; Kojima, Masaaki; Ohba, Shigeru

    2000-08-01

    Light brown [VO(5-NO2salen)]·2H2O (1; H2(5-NO2 salen)=N,N?-di-5-nitrosalicylidene-1,2-ethanediamine) and orange [VO(5-NO2sal-meso-stien)]·0.5H2O (2; H2(5-NO2sal-meso-stien)=N,N?-di-5-nitrosalicylidene-(R,S)(S,R)-1,2-diphenyl-1,2-ethanediamine) which have linear chain structures in the solid state turn dark brown and yellow-brown, respectively, when ground thoroughly in mortars. The IR spectra of 1 and 2 in Nujol mulls show strong V=O stretching bands at 875 and 905 cm-1, respectively. On the other hand, the spectra of the finely ground complexes in Nujol mulls show very weak V=O stretching bands. X-ray powder diffraction patterns of the ground complexes scarcely show diffraction peaks. The spectroscopic and magnetic data suggest that the linear chain structures in the crystals of 1 and 2 are destroyed on grinding to yield the fragments of the polymeric chains.

  2. Multifunctional Composites of Chiral Valine Derivative Schiff Base Cu(II) Complexes and TiO2

    PubMed Central

    Takeshita, Yuki; Takakura, Kazuya; Akitsu, Takashiro

    2015-01-01

    We have prepared four new Cu(II) complexes containing valine moieties with imidazole ligands at the fourth coordination sites and examined their photo-induced reactions with TiO2 in order of understanding the reaction mechanisms. Under a nitrogen atmosphere, the intermolecular electron transfer reactions (essentially supramolecular interactions) of these systems, which resulted in the reduction of Cu(II) species to Cu(I) ones, occurred after UV light irradiation. In this study, we have investigated the conditions of the redox reactions in view of substituent effects of aldehyde moieties. The results of cyclic voltammetry (CV) on an rotating ring-disk electrode (RRDE) suggested that the substitution effects and redox potentials were correlated. Density functional theory (DFT) and time-dependent DFT (TD-DFT) calculations were also performed to simulate the UV–Vis and circular dichroism (CD) spectra; the results revealed a reasonably good correlation between the substituent effects and the highest occupied molecular orbitals and the lowest unoccupied molecular orbitals (HOMO-LUMO) gaps associated with the most intense transition bands. In addition, we summarized the substitution effects of Cu(II) complexes for their corresponding UV light-induced reactions. PMID:25686033

  3. Novel mixed ligand complexes of bioactive Schiff base (E)-4-(phenyl (phenylimino) methyl) benzene-1,3-diol and 2-aminophenol/2-aminobenzoic acid: Synthesis, spectral characterization, antimicrobial and nuclease studies

    NASA Astrophysics Data System (ADS)

    Subbaraj, P.; Ramu, A.; Raman, N.; Dharmaraja, J.

    2014-01-01

    A novel bidentate Schiff base ligand has been synthesized using 2,4-dihydroxybenzophenone and aniline. Its mixed ligand complexes of MAB type [M = Mn(II), Co(II), Ni(II), Cu(II) and Zn(II); HA = Schiff base and B = 2-aminophenol/2-aminobenzoic acid] have been synthesized and characterized on the basis of spectral data UV-Vis, IR, 1H NMR, FAB-Mass, EPR, SEM and magnetic studies. All the complexes were soluble in DMF and DMSO. Elemental analysis and molar conductance values indicate that the complexes are non-electrolytes. HA binds with M(II) ions through azomethine and deprotonated phenolic group and B binds through the primary amine group and deprotonated phenolic/carboxylic groups. Using FAB-Mass the cleavage pattern of the ligand (HA) has been established. All the complexes adopt octahedral geometry around the metal ions. It has been confirmed with the help of UV-Vis, IR, 1H NMR and FAB-Mass spectral data. DNA binding activities of the complexes 1d and 2d are studied by UV-Vis spectroscopy and cleavage studies of Schiff base ligand and its complexes 1d and 2d have been by agarose gel electrophoresis method. In vitro biological activities of the free ligand (HA) and their metal complexes (1a-1e and 2a-2e) were screened against few bacteria, Escherichia coli, Staphylococcus saphyphiticus, Staphylococcus aureus, Pseudomonas aeruginosa and fungi Aspergillus niger, Enterobacter species, Candida albicans by well diffusion technique.

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

    PubMed

    Shakila, K; Kalainathan, S

    2015-01-25

    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). PMID:25173522

  5. 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).

  6. Exhibition of the Brønsted acid-base character of a Schiff base in palladium(ii) complex formation: lithium complexation, fluxional properties and catalysis of Suzuki reactions in water.

    PubMed

    Kumar, Rajnish; Mani, Ganesan

    2015-04-01

    The reaction of the dialdehyde N,N-di(?-formylpyrrolyl-?-methyl)-N-methylamine with two equiv. of 2,6-diisopropylaniline yielded two Schiff bases: bis(iminopyrrolylmethyl)amine () and its hydrolyzed monoimino compound () after column separation. The dimeric lithium complex [(HL)Li]2 () containing the monoanionic form of was obtained by treating with (n)BuLi. The presence of both proton donors and acceptors causes the diimino compound to undergo tautomerization to exhibit an amine-azafulvene structure, though the central amine nitrogen competes for a proton. As a result, in the presence of Pd(2+) ions, the cationic complex [Pd(Cl)(H2L)][Cl] () containing one pendant amine-azafulvene arm and the protonated central amine nitrogen was obtained. Its X-ray structure showed that the bond distances are reversed for the imino-pyrrole moiety relative to those in the structure of . However, the reaction of with [Pd(OAc)2] afforded the neutral complex [PdL] () containing the dianionic form of the ligand. The reaction of with [PdCl2(PhCN)2] yielded a zwitterionic complex [PdCl2(H2L')] () owing to the presence of the central amine nitrogen. The formation of these palladium complexes with the features mentioned above can be explained by invoking the Brønsted acid-base character of the Schiff base. Complex is fluxional owing to the up and down movements of the palladium square plane formed by two 5-membered palladacycles, which causes the interconversion of its enantiomers and is studied by the variable temperature (1)H NMR method. Furthermore, both complexes and are precatalysts for the Suzuki-Miyaura cross-coupling reaction in water. Sterically encumbered and electronically different substrates including activated aryl chlorides and benzyl halides gave the coupled products in very good yields. The reaction proceeds even at room temperature and in the presence of a large excess amount of mercury. PMID:25771810

  7. 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

  8. 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

    Microsoft Academic Search

    R. C. Maurya; S. Rajput

    2006-01-01

    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 (L1H), N-(3?-methyl-1?-phenyl-4?-valerylidene-2?-pyrazolin-5?-)sulfaguanidine (L2H), N-(3?-methyl-1?-phenyl-4?-valerylidene-2?-pyrazolin-5?-one)sulphanilamide (L3H) and N?(-3?-methyl-1?-phenyl-4?-valerylidene-2?-pyrazolin-5?-one)sulphamethoxazole (L4H) 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

  9. Copper(II) complexes of pyrrolidine dithiocarbamate

    Microsoft Academic Search

    Masood Sarwar; Saeed Ahmad; Sajjad Ahmad; Saqib Ali; Shafique Ahmed Awan

    2007-01-01

    Copper(II)-pyrrolidine dithiocarbamate (PDTC) complexes having the general formula, [Cu(PDTC)2], [Cu(PDTC)X2]? (where X = Cl?, I?, CN?, SCN?) and [Cu(PDTC)(en)]+ (en = ethylenediamine) have been prepared and characterized by IR spectroscopy and by thermogravimetric analysis (TGA and\\u000a DTA). The IR data suggests that coordination of pyrrolidine dithiocarbamate (PDTC) takes place through the two sulphur atoms\\u000a in a symmetrical bidentate fashion. The results of thermal analysis

  10. Spectral Characterization and 3D Molecular Modeling Studies of Metal Complexes Involving the O, N-Donor Environment of Quinazoline-4(3H)-one Schiff Base and Their Biological Studies

    PubMed Central

    Siddappa, Kuruba; Mane, Sunilkumar B.

    2014-01-01

    A simple condensation of 3-amino-2-methylquinazoline-4-one with 2-hydroxy-1-naphthaldehyde produced new tridentate ONO donor Schiff base ligand with efficient yield. The structural characterization of ligand and its Cu(II), Ni(II), Co(II), Mn(II), Zn(II), and Cd(II) complexes were achieved by the aid of elemental analysis, spectral characterization such as (UV-visible, IR, NMR, mass, and ESR), and magnetic data. The analytical and spectroscopic studies suggest the octahedral geometries of Cu(II), Co(II), Ni(II) and Mn(II) complexes and tetrahedral geometry of Zn(II) and Cd(II) complexes with the tridentate ONO Schiff base ligand. Furthermore, the conclusions drawn from these studies afford further support to the mode of bonding discussed on the basis of their 3D molecular modeling studies by considering different bond lengths, bond angles, and bond distance. The ligand and its metal complexes evaluated for their antimicrobial activity against Staphylococcus aureus (MTCC number 7443), Bacillus subtilis (MTCC number 9878), Escherichia coli (MTCC number 1698), Aspergillus niger (MTCC number 281), and Aspergillus flavus (MTCC number 277). The MIC of these compounds was found to be most active at 10??g/mL concentration in inhibiting the growth of the tested organisms. The DNA cleavage activity of all the complexes was studied by gel electrophoresis method. PMID:24678278

  11. Two di-nuclear Cd(II) and Mn(II) complexes with one new poly-dentate double Schiff base ligand derived from 1,10-phenanthroline: Syntheses, structures, and physical properties

    Microsoft Academic Search

    Cao-Yuan Niu; Ben-Lai Wu; Xin-Sheng Wan; Hong-Yun Zhang; Hong-Quan Zhang

    2010-01-01

    A new poly-dentate double Schiff base ligand 1,10-phenanthroline-2,9-dicarboxaldehyde-di-2-hydroxybenzoylhydrazone (H2L) was synthesized and structurally characterized. Two CdII and MnII dimers of this ligand were also synthesized, and their crystal structures and photoelectronic spectra were characterized. In the two dimers, ligand L acts as a bridge in the interesting mono–poly-dentate bridging mode. The ligand and its CdII complex strongly emit at 525nm

  12. New group 6 metal carbonyl complexes with 4,5-dimethyl-N,N-bis(pyridine-2-yl-methylene)benzene-1,2-diimine Schiff base: synthesis, spectral, cyclic voltammetry and biological activity studies.

    PubMed

    Mohamed, Rania G; Elantabli, Fatma M; Helal, Nadia H; El-Medani, Samir M

    2015-04-15

    Thermal reaction of M(CO)6 (M=Cr, Mo or W) with a Schiff base (DMPA) derived from the condensation of 4,5-dimethyl-1,2-phenylenediamine and pyridine-2-carboxaldehyde in THF in absence and presence of a secondary ligand; 2-aminobenzimidazole (Abz), thiourea (Tu) or 2-(2'-pyridyl)benzimidazole (pybz) were studied. The reaction of Cr(CO)6 gave the four complexes Cr2(CO)2(DMPA)2; 1, Cr(DMPA)2(Abz)2; 2, Cr2(CO)4(DMPA)2(Tu)2; 3 and Cr(DMPA)2(Pybz); 4, while the thermal reaction of Mo(CO)6 resulted in the formation of the two complexes Mo2(O)6(DMPA)2; 5, and Mo2(O)2(CO)2(DMPA)2(Tu)2; 6. Thermal reaction of W(CO)6 and the Schiff base DMPA gave the complex W(O)2(DMPA)2; 7. The ligand DMPA and its metal complexes have been reported and characterized based on elemental analyses, IR, (1)H NMR, magnetic measurements, and thermal analysis. Cyclic voltammetry and biological activity were also investigated. PMID:25670089

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

    NASA Astrophysics Data System (ADS)

    Mahjoub, Omima Abdalla; Farina, Yang

    2014-09-01

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

  14. 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.

  15. 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.

  16. Preparation, crystal structures, and magnetic features for a series of dinuclear [Ni(II)Ln(III)] Schiff-base complexes: evidence for slow relaxation of the magnetization for the Dy(III) derivative.

    PubMed

    Pasatoiu, Traian D; Sutter, Jean-Pascal; Madalan, Augustin M; Fellah, Fatima Zohra Chiboub; Duhayon, Carine; Andruh, Marius

    2011-07-01

    A series of dinuclear [Ni(II)Ln(III)] Schiff-base complexes (using a Schiff-base dicompartmental ligand derived from o-vanillin [H(2)valpn = 1,3-propanediylbis(2-iminomethylene-6-methoxy-phenol)]) with Ln = La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, and a hydroxo-bridged tetranuclear [Ni(II)Yb(III)] are reported. The crystal structures have been solved for 10 dinuclear complexes revealing four arrangements for the dinuclear units, which are modulated by the coordinated solvent molecules and the nitrato-anion interactions. The magnetic behaviors have been investigated, and the nature of the Ni(II)-Ln(III) exchange interaction has been emphasized by comparison with the behavior of the related [Zn(II)Ln(III)] derivatives. This allowed for establishing that the interaction within these compounds is antiferromagnetic with the 4f ions of the beginning of the Ln series and turns ferromagnetic from Gd(III) toward the end of the series. AC susceptibility investigations clearly show the occurrence of slow relaxation processes of the magnetization close to 2 K for the dinuclear [Ni(II)Dy(III)] complex. PMID:21634381

  17. Synthesis, spectroscopic characterization and biological activities of N?O? Schiff base ligand and its metal complexes of Co(II), Ni(II), Cu(II) and Zn(II).

    PubMed

    Al-Resayes, Saud I; Shakir, Mohammad; Abbasi, Ambreen; Amin, Kr Mohammad Yusuf; Lateef, Abdul

    2012-07-01

    The Schiff base ligand, bis(indoline-2-one)triethylenetetramine (L) obtained from condensation of triethylenetetramine and isatin was used to synthesize the complexes of type, [ML]Cl(2) [M=Co(II), Ni(II), Cu(II) and Zn(II)]. L was characterized on the basis of the results of elemental analysis, FT-IR, (1)H and (13)C NMR, mass spectroscopic studies. The stoichiometry, bonding and stereochemistries of complexes were ascertained on the basis of results of elemental analysis, magnetic susceptibility values, molar conductance and various spectroscopic studies. EPR, UV-vis and magnetic moments revealed an octahedral geometry for complexes. L and its Cu(II) and Zn(II) complexes were screened for their antibacterial activity. Analgesic activity of Cu(II) and Zn(II) complexes was also tested in rats by tail flick method. Both complexes were found to possess good antibacterial and moderate analgesic activity. PMID:22465773

  18. Synthesis, spectroscopic characterization and biological activities of N4O2 Schiff base ligand and its metal complexes of Co(II), Ni(II), Cu(II) and Zn(II)

    NASA Astrophysics Data System (ADS)

    Al-Resayes, Saud I.; Shakir, Mohammad; Abbasi, Ambreen; Amin, Kr. Mohammad Yusuf; Lateef, Abdul

    The Schiff base ligand, bis(indoline-2-one)triethylenetetramine (L) obtained from condensation of triethylenetetramine and isatin was used to synthesize the complexes of type, [ML]Cl2 [M = Co(II), Ni(II), Cu(II) and Zn(II)]. L was characterized on the basis of the results of elemental analysis, FT-IR, 1H and 13C NMR, mass spectroscopic studies. The stoichiometry, bonding and stereochemistries of complexes were ascertained on the basis of results of elemental analysis, magnetic susceptibility values, molar conductance and various spectroscopic studies. EPR, UV-vis and magnetic moments revealed an octahedral geometry for complexes. L and its Cu(II) and Zn(II) complexes were screened for their antibacterial activity. Analgesic activity of Cu(II) and Zn(II) complexes was also tested in rats by tail flick method. Both complexes were found to possess good antibacterial and moderate analgesic activity.

  19. 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.

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

    PubMed

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

    2015-03-01

    New generation of copper(II) complexes with aminoalkylaminoneocryptolepine as bidentate ligands has been synthesized and it is characterized by elemental analyses, magnetic moment, spectra (IR, UV-Vis, (1)H NMR and ESR) and thermal studies. The IR data suggest the coordination modes for ligands which behave as a bidentate with copper(II) ion. Based on the elemental analysis, magnetic studies, electronic and ESR data, binuclear square planar geometry was proposed for complexes 7a, 7b, square pyramidal for 9a, 9b and octahedral for 8a, 8b, 10a, 10b. The molar conductance in DMF solution indicates that all complexes are electrolyte except 7a and 7b. The ESR spectra of solid copper(II) complexes in powder form showed an axial symmetry with (2)B1g as a ground state and hyperfine structure. The thermal stability and degradation of the ligands and their metal complexes were studied employing DTA and TG methods. The metal-free ligands and their copper(II) complexes were tested for their in vitro anticancer activity against human colon carcinoma (HT-29). The results showed that the synthesized copper(II) complexes exhibited higher anticancer activity than their free ligands. Of all the studied copper(II) complexes, the bromo-substituted complex 9b exhibited high anticancer activity at low micromolar inhibitory concentrations (IC50=0.58?M), compared to the other complexes and the free ligands. PMID:24867072

  1. 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

  2. Formation, reactivity and redox properties of carbon- and sulfur-bridged diiron complexes derived from dibenzothienyl Schiff bases: effect of N,N- and N,P-chelating moieties.

    PubMed

    Santo, Kiyokazu; Hirotsu, Masakazu; Kinoshita, Isamu

    2015-02-17

    Dibenzothienyl Schiff bases, DBT-NN and DBT-NP, were derived from condensation of 4-formyldibenzothiophene with N,N-dimethylethylenediamine and 2-(diphenylphosphino)ethylamine, respectively. A photochemical reaction of [Fe(CO)5] with DBT-NN produced diiron complexes, [Fe2(?-DBT-NN)(CO)6] () and [{Fe(?-BPT-NN-?(3)S,C,N)(CO)2}Fe(CO)3] (). Complex has ? coordination of a Schiff base C[double bond, length as m-dash]N bond and an N,N-chelate, while has an S,C,N-tridentate ligand having an uncoordinated dimethylamino group. The corresponding reaction with DBT-NP produced a diiron complex of an S,C,N,P-tetradentate ligand, [{Fe(?-BPT-NP-?(4)S,C,N,P)(CO)}Fe(CO)3] (), which has an N,P-chelate, via the DBT-NP complex [Fe(DBT-NP-?P)(CO)4] (). Reactions of and with one equivalent of PMe2Ph gave the monosubstituted complexes [{Fe(?-BPT-NN-?(3)S,C,N)(CO)2}Fe(CO)2(PMe2Ph)] () and [{Fe(?-BPT-NP-?(4)S,C,N,P)(CO)}Fe(CO)2(PMe2Ph)] (), respectively. The corresponding reactions with an excess of PMe2Ph produced mononuclear complexes, trans-[Fe(BPT-NN-?(3)S,C,N)(CO)(PMe2Ph)2] () and [Fe(BPT-NP-?(4)S,C,N,P)(CO)(PMe2Ph)] (), respectively. Complexes and were structurally characterized by X-ray crystallography. Complexes , , and have similar dinuclear structures with different carbonyl/phosphine substitution patterns. Cyclic voltammograms of , and showed two one-electron reduction processes, and more negative potentials were observed for . The shift of the redox potentials are rationalized by the electron-donating character of the phosphine ligands, which suggests that the reduction occurs at the asymmetrically bridged diiron core. PMID:25623444

  3. Organotin(IV) complexes derived from Schiff base N'-[(1E)-(2-hydroxy-3-methoxyphenyl)methylidene]pyridine-4-carbohydrazone: synthesis, in vitro cytotoxicities and DNA/BSA interaction.

    PubMed

    Hong, Min; Geng, Honglin; Niu, Meiju; Wang, Fei; Li, Dacheng; Liu, Jifeng; Yin, Handong

    2014-10-30

    Five organotin(IV) compounds were synthesized from N'-[(1E)-(2-hydroxy-3-methoxyphenyl)methylidene]pyridine-4-carbohydrazone and the corresponding dialkyltin(IV) or trialkyltin(IV) precursor. Solid state structures were determined by IR, elemental analysis, NMR spectroscopy, and for 1, 2, 4 and 5 single crystal X-ray diffraction analysis. Compounds 1, 2 and 4 are monomers with the tin atoms five-coordinated in distorted trigonal bipyramid, of which the deprotonated Schiff base ligand chelate to tin center in the enolic tridentate mode. Differently, in compound 5, the enolization does not occur for the Schiff base ligand, and only the pyridinyl N atom and the deprotonated phenol hydroxyl oxygen atom participate in the coordination. Fascinatingly, six trimethyltin(IV) coordination units are linked by the Sn?N weak interaction atoms and form a 72-membered crown-like macrocycle. Preliminary in vitro cytotoxicity studies on five human tumor cells lines (HL-60, A549, HT-29, HCT-116 and Caco-2) by MTT assay reveal that di-n-butyltin(IV) complex 2 and diphenyltin(IV) complex 4 triggered significant antiproliferative effects in cultured tumor cells, and their cytotoxic activity correlates with intracellular organotin(IV) concentration. The interaction of the complexes with calf thymus DNA (CT-DNA) has been explored by absorption and emission titration methods, which revealed that complexes 2 and 4 interact with CT-DNA through groove-binding and partial intercalation of the extended planar ligand with the DNA base stack. Further, the albumin interactions of complexes 2 and 4 were investigated using fluorescence quenching spectra and synchronous fluorescence spectra. Studies reveal that di-n-butyltin(IV) complex 2 with higher cytotoxicity show stronger DNA/BSA interaction than diphenyltin(IV) complex 4. PMID:25216377

  4. Synthesis and X-ray structure analysis of a new binuclear Schiff base Co(II) complex with the ligand N,N'-bis(3-methoxysalicylidene)-1,4-butanediamine

    SciTech Connect

    Nasr-Esfahani, M., E-mail: m-nasresfahani@iaun.ac.ir [Islamic Azad University, Najafabad Branch, Department of Materials Science and Engineering (Iran, Islamic Republic of)

    2009-12-15

    The title binuclear complex, tris[N,N-bis(3-methoxysalicylidene)-1,4-diaminobutane] dicobalt(II), C{sub 60}H{sub 70}Co{sub 2}N{sub 6}O{sub 15}, was prepared by the reaction of the tetradentate Schiff base ligand bis(3-methoxysalicylidene)-1,4-diaminobutane and Co(CH{sub 3}COO){sub 2} . 4H{sub 2}O in a ethanol solution and structurally characterized by single-crystal X-ray diffraction. This complex has a dinuclear structure where two Co(II) ions are bridged by one N{sup 0},N'-bis(3-methoxysalicylidene)-1,4-diaminobutane. The two Co(II) ions, have two distorted octahedral coordination involving two O and two N atoms.

  5. 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

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

    NASA Astrophysics Data System (ADS)

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

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

  7. The effect of coordinated solvent ligands on the solid-state structures of compounds involving uranyl nitrate and Schiff bases

    Microsoft Academic Search

    David J Evans; Peter C Junk; Matthew K Smith

    2002-01-01

    A range of solvent adducts of uranyl complexes of the Schiff base ligands salen (salen?N,N?-ethylenebis(salicylidenimine)) and salpn (?N,N?-propylenebis(salicylidenimine)) have revealed similar morphologies about the uranium centre. Subtle differences in hydrogen bonding arrays, types of solvents and conformation of the Schiff base ligands result in vastly different crystal packing motifs.

  8. Syntheses, spectroscopic characterization, thermal study, molecular modeling, and biological evaluation of novel Schiff's base benzil bis(5-amino-1,3,4-thiadiazole-2-thiol) with Ni(II), and Cu(II) metal complexes

    NASA Astrophysics Data System (ADS)

    Chandra, Sulekh; Gautam, Seema; Rajor, Hament Kumar; Bhatia, Rohit

    2015-02-01

    Novel Schiff's base ligand, benzil bis(5-amino-1,3,4-thiadiazole-2-thiol) was synthesized by the condensation of benzil and 5-amino-1,3,4-thiadiazole-2-thiol in 1:2 ratio. The structure of ligand was determined on the basis of elemental analyses, IR, 1H NMR, mass, and molecular modeling studies. Synthesized ligand behaved as tetradentate and coordinated to metal ion through sulfur atoms of thiol ring and nitrogen atoms of imine group. Ni(II), and Cu(II) complexes were synthesized with this nitrogen-sulfur donor (N2S2) ligand. Metal complexes were characterized by elemental analyses, molar conductance, magnetic susceptibility measurements, IR, electronic spectra, EPR, thermal, and molecular modeling studies. All the complexes showed molar conductance corresponding to non-electrolytic nature, expect [Ni(L)](NO3)2 complex, which was 1:2 electrolyte in nature. [Cu(L)(SO4)] complex may possessed square pyramidal geometry, [Ni(L)](NO3)2 complex tetrahedral and rest of the complexes six coordinated octahedral/tetragonal geometry. Newly synthesized ligand and its metal complexes were examined against the opportunistic pathogens. Results suggested that metal complexes were more biological sensitive than free ligand.

  9. 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 of humic substances (HS) and their complexes with metal cations is a matter of ongoing debate, possibly indicating six-dentate coordination of Cu2+ by HS. Introduction Humic substances (HS

  10. Heterobimetallic Zn(II)-Ln(III) phenylene-bridged schiff base complexes, computational studies, and evidence for singlet energy transfer as the main pathway in the sensitization of near-infrared Nd3+ luminescence.

    PubMed

    Lo, Wing-Kit; Wong, Wai-Kwok; Wong, Wai-Yeung; Guo, Jianping; Yeung, Kai-Tai; Cheng, Yuen-Kit; Yang, Xiaoping; Jones, Richard A

    2006-11-13

    A series of 3d-4f heterobimetallic phenylene-bridged Schiff base complexes of the general formula [Zn(mu-L1)Ln(NO3)3(S)n] [Ln = La (1), Nd (2), Gd (3), Er (4), Yb (5); S = H(2)O, EtOH; n = 1, 2; H2L1 = N,N'-bis(3-methoxysalicylidene)phenylene-1,2-diamine] and [Zn(mu-L2)Ln(NO3)3(H2O)n] [Ln = La (6), Nd (7), Gd (8), Er (9), Yb (10); n = 1, 2; H(2)L(2) = N,N'-bis(3-methoxy-5-p-tolylsalicylidene)phenylene-1,2-diamine] were synthesized and characterized. Complexes 1, 2, 4, and 7 were structurally characterized by X-ray crystallography. At room temperature in CH(3)CN, both neodymium(III) (2 and 7) and ytterbium(III) (5 and 10) complexes also exhibited, in addition to the ligand-centered emission in the UV-vis region, their lanthanide(III) ion emission in the near-infrared (NIR) region. The photophysical properties of the zinc(II) phenylene-bridged complexes (ZnL1 and ZnL2) were measured and compared with those of the corresponding zinc(II) ethylene-bridged complexes (ZnL3 and ZnL4). Our results revealed that, at 77 K, both ligand-centered triplet (3LC) and singlet (1LC) states existed for the ethylene-bridged complexes (ZnL3 and ZnL4), whereas only the (1)LC state was detected for the phenylene-bridged complexes (ZnL1 and ZnL2). NIR sensitization studies of [Zn(mu-L')Nd(NO3)3(H2O)n] (L' = L1-L4) complexes further showed that Nd3+ sensitization took place via the 3LC and 1LC states when the spacer between the imine groups of the Schiff base ligand was an ethylene and a phenylene unit, respectively. Ab initio calculations show that the observed differences can be attributed to the difference in the molecular vibrational properties and electron densities of the electronic states between the ethylene- and phenylene-bridged complexes. PMID:17083231

  11. Synthesis, spectroscopic, thermal and electrical conductivity studies of three charge transfer complexes formed between 1,3-di[( E)-1-(2-hydroxyphenyl)methylideneamino]-2-propanol Schiff base and different acceptors

    NASA Astrophysics Data System (ADS)

    Refat, Moamen S.; Ibrahim, Mohamed M.; Moussa, Mohamed A. A.

    2012-01-01

    Charge-transfer complexes (CTC) resulting from interactions of 1,3-di[( E)-1-(2-hydroxyphenyl) methylideneamino]-2-propanol Schiff base with some acceptors such as iodine (I2), bromine (Br2), and picric acid (PiA) have been isolated in the solid state in a chloroform solvent at room temperature. Based on elemental analysis, UV-Vis, infrared, and 1H NMR spectra, and thermogravimetric analysis (TG/DTG) of the solid CTC, [(Schiff)(I2)] (1), [(Schiff)(Br2)] complexes with a ratio of 1:1 and [(Schiff)(PiA)3] complexes with 1:3 have been prepared. In the picric acid complex, infrared and 1H NMR spectroscopic data indicate that the charge-transfer interaction is associated with a hydrogen bonding, whereas the iodine and bromine complexes were interpreted in terms of the formation of dative ion pairs [Schiff+, I{2/•-}] and [Schiff+, Br{2/•-}], respectively. Kinetic parameters were obtained for each stage of thermal degradation of the CT complexes using Coats-Redfern and Horowitz-Metzger methods. DC electrical properties as a function of temperature of these charge transfer complexes have been studied.

  12. Synthesis, structural characterization, thermal studies, catalytic efficiency and antimicrobial activity of some M(II) complexes with ONO tridentate Schiff base N-salicylidene-o-aminophenol (saphH2)

    NASA Astrophysics Data System (ADS)

    Abdel Aziz, Ayman A.; Salem, Abdel Naby M.; Sayed, Mostafa A.; Aboaly, Mohamed M.

    2012-02-01

    The reactions of acetate salts of M(II) (M = Mn, Co, Ni, Cu and Zn) with N-salicylidene-o-aminophenol (saphH2) in ethyl alcohol afforded new four coordinated complexes with the general formula [M(II)(saph)(H2O)]. The complexes have been fully characterized by microanalysis, molar conductance, magnetic susceptibility, 1H NMR, IR, UV-Vis, ESR, mass spectra and thermogravimetric analysis (TGA). The experimental data have been shown that all complexes are mononuclear with the M(II) being coordinated by a dianionic tridentate Schiff base ligand, through the deprotonated two enolic oxygen and the azomethine nitrogen atoms. UV-Vis spectra and magnetic moments have been suggested square planar stereochemistry for Co(II) and Cu(II) complexes, and tetrahedral geometry has been suggested for Mn(II), Ni(II) and Zn(II) complexes. The new complexes have been tested for their abilities to catalyze aerial oxidation of benzaldehyde to benzoic acid. Finally, in view of the biological activity, antibacterial and antifungal tests of the ligand and its complexes have been carried out and the results were compared with some known antibiotics.

  13. Enantiomeric fluoro-substituted benzothiazole Schiff base-valine Cu(II)/Zn(II) complexes as chemotherapeutic agents: DNA binding profile, cleavage activity, MTT assay and cell imaging studies.

    PubMed

    Alizadeh, Rahman; Yousuf, Imtiyaz; Afzal, Mohd; Srivastav, Saurabh; Srikrishna, Saripella; Arjmand, Farukh

    2015-02-01

    To evaluate the biological preference of chiral drugs toward DNA target, new metal-based chemotherapeutic agents of Cu(II) and Zn(II), l-/d-fluorobenzothiazole Schiff base-valine complexes 1 &2 (a and b), respectively were synthesized and thoroughly characterized. Preliminary in vitro DNA binding studies of ligand L and complexes 1 &2 (a and b) were carried out in Tris-HCl buffer at pH 7.2 to demonstrate the chiral preference of l-enantiomeric complexes over the d-analogues. The extent of DNA binding propensity was ascertained quantitatively by Kb, K and Ksv values which revealed greater binding propensity by l-enantiomeric Cu(II) complex 1a and its potency to act as a chemotherapeutic agent. The cleavage studies with pBR322 plasmid DNA revealed higher nuclease activity of 1a as compared to 2avia hydrolytic cleavage mechanism. The complexes 1 &2 (a and b) were also screened for antimicrobial activity which demonstrated significantly good activity for l-enantiomeric complexes. Furthermore, cytotoxicity of the complexes 1a and 1b was evaluated by the MTT assay on human HeLa cancer cell line which implicated that more than 50% cells were viable at 15?M. These results were further validated by cell imaging studies which demonstrated the nuclear blebbing. PMID:25600265

  14. Synthesis, characterization, thermal study and biological evaluation of Cu(II), Co(II), Ni(II) and Zn(II) complexes of Schiff base ligand containing thiazole moiety

    NASA Astrophysics Data System (ADS)

    Nagesh, G. Y.; Mahendra Raj, K.; Mruthyunjayaswamy, B. H. M.

    2015-01-01

    The novel Schiff base ligand 2-(4-(dimethylamino)benzylidene)-N-(4-phenylthiazol-2-yl)hydrazinecarboxamide (L) obtained by the condensation of N-(4-phenylthiazol-2-yl)hydrazinecarboxamide with 4-dimethylaminobenzaldehyde and its newly synthesized Cu(II), Co(II), Ni(II) and Zn(II) complexes have been characterized by microanalysis, magnetic susceptibility, molar conductance, thermal analysis, FT-IR, 1H NMR, ESI mass, UV-Visible, ESR spectroscopy and powder X-ray diffraction data. The newly synthesized ligand behaves as a bidentate ON donor. The IR results confirmed the bidentate binding of the ligand involving oxygen atom of amide carbonyl and azomethine nitrogen. 1H NMR spectral data of the ligand (L) and its Zn(II) complex agreed well with the proposed structures. In order to evaluate the effect of antimicrobial activity of metal ions upon chelation, the newly synthesized ligand and its metal complexes were screened for their antibacterial and antifungal activities by minimum inhibitory concentration (MIC) method. The DNA cleavage activities were studied using plasmid DNA pBR322 as a target molecule by agarose gel electrophoresis method. The brine shrimp bioassay was also carried out to study the in vitro cytotoxicity properties of all the compounds against Artemia salina. Furthermore, the antioxidant activity of the ligand (L) and its metal complexes were determined in vitro by reduction of 1,1-diphenyl-2-picryl hydrazyl (DPPH), the ligand exhibited potent in vitro - antioxidant activity than its metal complexes.

  15. Acute toxicity and gastroprotective effect of the Schiff base ligand ¹H-indole-3-ethylene-5-nitrosalicylaldimine and its nickel (II) complex on ethanol induced gastric lesions in rats.

    PubMed

    Ibrahim, Mohamed Mustafa; Ali, Hapipah Mohd; Abdullah, Mahmood Ameen; Hassandarvish, Pouya

    2012-01-01

    The present study was performed to evaluate the gastroprotective activity of Schiff base ligand derived from the condensation reaction of tryptamine (an indole derivative) and 5-nitrosalicylaldehyde (TNS) and its nickel (II) complex against ethanol-induced gastric ulcer in rats. The compounds were orally administered with low (30 mg/kg) and high (60 mg/kg) doses to ulcer-induced Sprague-Dawley rats. Macroscopically, the ulcer control group exhibited severe mucosal injury, whereas pre-treatment with either cimetidine or TNS and its nickel (II) complex each resulted in significant protection against gastric mucosal injury. Flattening of gastric mucosal folds was also observed in rats pretreated with TNS and its nickel complex. Histological studies of the gastric wall of ulcer control group revealed severe damage of gastric mucosa, along with edema and leucocytes infiltration of the submucosal layer compared to rats pre-treated with either cimetidine or TNS and its nickel (II) compound, where there was marked gastric protection along with reduction of edema and leucocytes infiltration of the submucosal layer. Acute toxicity study done on mice with a higher dose of 5 g/kg of TNS and its nickel (II) complex did not manifest any toxicological signs. Research finding suggest that TNS and its nickel (II) complex could be considered as effective gastroprotective compounds. PMID:23090023

  16. Oxaziridine-mediated enantioselective aminohydroxylation of styrenes catalyzed by copper(II) bis(oxazoline) complexes.

    PubMed

    Michaelis, David J; Williamson, Kevin S; Yoon, Tehshik P

    2009-06-27

    We report an oxaziridine-mediated enantioselective aminohydroxylation of olefins catalyzed by a chiral copper(II) bis(oxazoline) complex. A variety of styrenic olefins undergo efficient aminohydroxylation with excellent regioselectivity and synthetically useful levels of enantioselectivty (up to 84% ee). The reaction can be conducted on multi-gram scale with as little as 2 mol% of the copper(II) catalyst. Hydrolysis of the resulting 1,3-oxazolines under acidic conditions produces N-sulfonyl amino alcohols that can be purified by recrystallization to afford very high levels of enantioselectivity. PMID:20161136

  17. Oxaziridine-mediated enantioselective aminohydroxylation of styrenes catalyzed by copper(II) bis(oxazoline) complexes

    PubMed Central

    Michaelis, David J.; Williamson, Kevin S.; Yoon, Tehshik P.

    2009-01-01

    We report an oxaziridine-mediated enantioselective aminohydroxylation of olefins catalyzed by a chiral copper(II) bis(oxazoline) complex. A variety of styrenic olefins undergo efficient aminohydroxylation with excellent regioselectivity and synthetically useful levels of enantioselectivty (up to 84% ee). The reaction can be conducted on multi-gram scale with as little as 2 mol% of the copper(II) catalyst. Hydrolysis of the resulting 1,3-oxazolines under acidic conditions produces N-sulfonyl amino alcohols that can be purified by recrystallization to afford very high levels of enantioselectivity. PMID:20161136

  18. 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.

  19. Two water-soluble copper(II) complexes: synthesis, characterization, DNA cleavage, protein binding activities and in vitro anticancer activity studies.

    PubMed

    Lu, Jing; Sun, Qian; Li, Jun-Ling; Jiang, Lin; Gu, Wen; Liu, Xin; Tian, Jin-Lei; Yan, Shi-Ping

    2014-08-01

    Two water-soluble ternary copper(II) complexes of [Cu(L)Cl](ClO4) (1) and [Cu(L)Br2] (2) (L=(2-((quinolin-8-ylimino)methyl)pyridine)) were prepared and characterized by various physico-chemical techniques. Both 1 and 2 were structurally characterized by X-ray crystallography. The crystal structures show the presence of a distorted square-pyramidal CuN3Cl2 (1) or CuN3Br2 (2) geometry in which Schiff-base L acts as a neutral tridentate ligand. Both complexes present intermolecular ?-? stacking interactions between quinoline and pyridine rings. The interaction of two complexes with CT-DNA (calf thymus-DNA) and BSA (bovine serum albumin) was studied by means of various spectroscopy methods, which revealed that 1 and 2 could interact with CT-DNA through intercalation mode, and could quench the intrinsic fluorescence of BSA in a static quenching process. Furthermore, the competition experiment using Hoechst 33258 indicated that two complexes may bind to CT-DNA by a minor groove. DNA cleavage experiments indicate that the complexes exhibit efficient DNA cleavage activities without any external agents, and hydroxyl radical (HO) and singlet oxygen ((1)O2) may serve as the major cleavage active species. Notably, the in vitro cytotoxicity of the complexes on three human tumor cells lines (HeLa, MCF-7, and A549) demonstrates that two compounds have broad-spectrum antitumor activity with quite low IC50 ranges of 0.43-1.85?M. Based on the cell cycle experiments, 1 and 2 could delay or inhibit cell cycle progression through the S phase. PMID:24803026

  20. Synthesis, spectral characterization and antimicrobial studies of nano-sized oxovanadium(IV) complexes with Schiff bases derived from 5-(phenyl/substituted phenyl)-2-hydrazino-1,3,4-thiadiazole and indoline-2,3-dione

    NASA Astrophysics Data System (ADS)

    Sahani, M. K.; Yadava, U.; Pandey, O. P.; Sengupta, S. K.

    A new class of oxovanadium(IV) complexes with Schiff bases derived by the condensation of 5-(phenyl/substituted phenyl)-2-hydrazino-1,3,4-thiadiazoles and indoline-2,3-dione have been prepared in ethanol in the presence of sodium acetate. Micro-analytical data, magnetic susceptibility, UV-Vis, IR, EPR and XRD spectral techniques were used to confirm the structures. Electronic absorption spectra of the complexes suggest a square-pyramidal geometry. The oxovanadium(IV) complexes have monoclinic crystal system and particle sizes were found to be in the range 18.0 nm to 24.0 nm (nano-size). In vitro antifungal activity of synthesized compounds was determined against fungi Aspergillus niger, Colletotrichum falcatum and Colletotrichum pallescence and in vitro antibacterial activity was determined by screening the compounds against Gram-negative (Escherichia coli and Salmonella typhi) and Gram-positive (Staphylococcus aureus and Bacillus subtilis) bacterial strains. The oxovanadium(IV) complexes have higher antimicrobial effect than free ligands.

  1. Fe(II)(pap-5NO2)2 and Fe(II)(qsal-5NO2)2 Schiff-Base Spin-Crossover Complexes: A Rare Example with Photomagnetism and Room-Temperature Bistability.

    PubMed

    Iasco, Olga; Rivière, Eric; Guillot, Régis; Buron-Le Cointe, Marylise; Meunier, Jean-François; Bousseksou, Azzedine; Boillot, Marie-Laure

    2015-02-16

    We focus here on the properties of Fe complexes formed with Schiff bases involved in the chemistry of Fe(III) spin-transition archetypes. The neutral Fe(pap-5NO2)2 (1) and Fe(qsal-5NO2)2·Solv (2 and 2·Solv) compounds (Solv = 2H2O) derive from the reaction of Fe(II) salts with the condensation products of pyridine-2-carbaldehyde with 2-hydroxy-5-nitroaniline (Hpap-5NO2) or 5-nitrosalicylaldehyde with quinolin-8-amine (Hqsal-5NO2), respectively. While the Fe(qsal-5NO2)2·Solv solid is essentially low spin (S = 0) and requires temperatures above 300 K to undergo a S = 0 ? S = 2 spin-state switching, the Fe(pap-5NO2)2 one presents a strongly cooperative first-order transition (T? = 291 K, T? = 308 K) centered at room temperature associated with a photomagnetic effect at 10 K (TLIESST = 58 K). The investigation of these magnetic behaviors was conducted with single-crystal X-ray diffraction (1, 100 and 320 K; 2, 100 K), Mössbauer, IR, UV-vis (1 and 2·Solv), and differential scanning calorimetry (1) measurements. The Mössbauer analysis supports a description of these compounds as Fe(II) Schiff-base complexes and the occurrence of a metal-centered spin crossover process. In comparison with Fe(III) analogues, it appears that an expanded coordination sphere stabilizes the valence 2+ state of the Fe ion in both complexes. Strong hydrogen-bonding interactions that implicate the phenolato group bound to Fe(II) promote the required extra-stabilization of the S = 2 state and thus determines the spin transition of 1 centered at room temperature. In the lattice, the hydrogen-bonded sites form infinite chains interconnected via a three-dimensional network of intermolecular van der Waals contacts and ?-? interactions. Therefore, the spin transition of 1 involves the synergetic influence of electrostatic and elastic interactions, which cause the enhancement of cooperativity and result in the bistability at room temperature. PMID:25590643

  2. Tale of a twist: magnetic and optical switching in copper(II) semiquinone complexes.

    PubMed

    Verma, Pratik; Weir, John; Mirica, Liviu; Stack, T Daniel P

    2011-10-17

    An intermediate (C) that is observed in both phenol hydroxylation and catechol oxidation with the side-on peroxide species [Cu(2)O(2)(DBED)(2)](2+) (DBED = N(1),N(2)-di-tert-butylethane-1,2-diamine) is identified as a copper(II) semiquinone species ([1](+)) through independent synthesis and characterization. The reaction of the redox-active 3,5-di-tert-butylquinone ligand with [(DBED)Cu(I)(MeCN)](+) yields a copper(II) semiquinone [1](+) complex with a singlet ground state and an intense purple chromophore (?(580) ~ 3500 M(-1) cm(-1)). All other copper(II) semiquinone complexes characterized to date are paramagnetic and weakly colored (?(800) ~ 500 M(-1) cm(-1)). Antiferromagnetic coupling between the Cu(II) center and the semiquinone radical in [1](+) is characterized by paramagnetic (1)H NMR and SQUID magnetometry. Comparative X-ray crystal structures along with density functional theory calculations correlate the geometric structures of copper(II) semiquinone complexes with their magnetic and optical properties. The unique observable properties of [1](+) originate from an increase in the overlap of the Cu 3d and semiquinone ? orbitals resulting from a large rhombic distortion in the structure with a twist of 51°, attributable to the large isotropic demands of the tert-butyl substituents of the DBED ligand. Independent characterization of [1](+) allows the spectroscopic yields of intermediate C to be quantified in this intriguing hydroxylation reaction. PMID:21696132

  3. Characterization, molecular modeling and antimicrobial activity of metal complexes of tridentate Schiff base derived from 5-acetyl-4-hydroxy-2H-1,3-thiazine-2,6(3H)-dione and 2-aminophenol

    NASA Astrophysics Data System (ADS)

    Adly, Omima M. I.

    Metal complexes of Ni(II), Co(II), Cd(II), VO(IV) and UO2(VI) as well as several Cu(II) salts, including Cl,NO3-,AcO,ClO4- and SO4-2 with a tridentate O2N donor Schiff base ligand (H2L), synthesized by condensation of 5-acetyl-4-hydroxy-2H-1,3-thiazine-2,6(3H)-dione with 2-aminophenol, were prepared and characterized on the basis of elemental analyses, spectral, magnetic, molar conductance and thermal gravimetric analysis. Square planar, tetrahedral and octahedral geometries have been assigned to the prepared complexes. Molecular parameters of the ligand and its metal complexes have been calculated and correlated with the experimental data, and the changes of bond lengths are linearly correlated with IR data. The antimicrobial activities of the synthesized compounds were tested in vitro against the sensitive organisms Staphylococcus aureus as Gram positive bacteria, Proteus vulgaris as Gram negative bacteria and Candida albicans as fungus strain, and the results are discussed.

  4. Cd(II) and Zn(II) complexes of two new hexadentate Schiff base ligands derived from different aldehydes and ethanol amine; X-ray crystal structure, IR and NMR spectroscopy studies

    NASA Astrophysics Data System (ADS)

    Golbedaghi, Reza; Rezaeivala, Majid; Albeheshti, Leila

    2014-11-01

    Four new [Cd(H2L1)(NO3)]ClO4 (1), [Zn(H2L1)](ClO4)2 (2), [Cd(H2L2)(NO3)]ClO4 (3), and [Zn(H2L2)](ClO4)2 (4), complexes were prepared by the reaction of two new Schiff base ligands and Cd(II) and Zn(II) metal ions in equimolar ratios. The ligands H2L1 and H2L2 were synthesized by reaction of 2-[2-(2-formyl phenoxy)ethoxy]benzaldehyde and/or 2-[2-(3-formyl phenoxy)propoxy]benzaldehyde and ethanol amine and characterized by IR, 1H and 13C NMR spectroscopy. All complexes were characterized by IR, 1H and 13C NMR, COSY, and elemental analysis. Also, the complex 1 was characterized by X-ray in addition to the above methods. The X-ray crystal structure of compound 1 showed that all nitrogen and oxygen atoms of ligand (N2O4) and a molecule of nitrate with two donor oxygen atom have been coordinated to the metal ion and the Cd(II) ion is in an eight-coordinate environment that is best described as a distorted dodecahedron geometry.

  5. Pincer ligands based on ?-amino acids: III. New ligands based on 4-substituted phenols and their copper complexes. Enantioselective recognition of tyrosine

    Microsoft Academic Search

    N. E. Borisova; V. A. Knizhnikov; T. G. Gulevich; M. Yu. Seliverstov; E. A. Borisov; M. D. Reshetova

    2009-01-01

    Reactions of L-methionine, L-serine, and L-valine with 5-substituted-2-hydroxybenzene-1,3-dicarbaldehydes gave a series of\\u000a chiral Schiff base pincer ligands which were reduced to the corresponding diamines. The new Schiff base ligands reacted with\\u000a copper(II) chloride to form dinuclear copper complexes which were found to be capable of recognizing tyrosine enantiomers\\u000a in aqueous solution. The structure of the complexes was determined on the

  6. Synthesis, characterization, and 3D-molecular modeling and analysis of some copper(II) chelates in O,N-donor coordination pattern involving Schiff bases derived from 4-butyryl-3-methyl-1-phenyl-2-pyrazolin-5-one and some sulfa drugs

    Microsoft Academic Search

    R. C. Maurya; S. Jhamb; S. Roy; J. Chourasia; A. K. Sharma; P. Vishwakarma

    The synthesis of five new chelates of copper(II) of the general formula [Cu(LH)2(Cl)2], where LH=N-(4?-butyrylidine-3?-methyl-1?-phenyl-2?-pyrazolin-5?-one)sulfamethoxazole (bumphp-smzH, I), N-(4?-butyrylidine-3?-methyl-1?-phenyl-2?-pyrazolin-5?-one)sulfadimidine (bumphp-sdmH, II), N-(4?-butyrylidine-3?-methyl-1?-phenyl-2?-pyrazolin-5?-one)sulfanilamide (bumphp-snmH, III), N-(4?-butyrylidine-3?-methyl-1?-phenyl-2?-pyrazolin-5?-one)sulfamoxole (bumphp-smlH, IV) or N-(4?-butyrylidine-3?-methyl-1’-phenyl-2?-pyrazolin-5?-one)sulfaguanidine (bumphp-sgdH, V) has been carried out. The complexes have been characterized by elemental analyses, copper determination, molar conductance, magnetic and decomposition temperature measurements, electron spin resonance, thermogravimetry, infrared, and electronic spectral studies.

  7. 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

  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.

    PubMed

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

    2005-06-15

    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 4.2.1.1): the cytosolic isoforms I and II, as well as the tumor-associated, transmembrane isozymes CA IX and XII. Except for the sulfaguanidine-derived compounds which were devoid of activity against all isozymes, the other sulfonamides and their metal complexes showed interesting inhibitory activity. Against isozyme CA I, the inhibition constants were in the range of 13-100 nM, against isozyme CA II in the range of 1.9-102 nM, against isozyme CA IX in the range of 6.3-48nM, and against CA XII in the range of 5.9-50nM. Generally, the formyl-chromone derived compounds were better CA inhibitors as compared to the corresponding 6-methyl-chromone derivatives, and for the simple, benzenesulfonamide derivatives activity increased with an increase of the spacer from sulfanilamide to homosulfanilamide and 4-aminoethylbenzenesulfonamide derivatives, respectively. Some of these compounds may show applications for the development of therapies targeting hypoxic tumors in which CA IX and XII are often highly overexpressed. PMID:15908204

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

    SciTech Connect

    Pang, Haijun; Yang, Ming; Kang, Lu [Key Laboratory of Green Chemical Engineering and Technology of College of Heilongjiang Province, College of Chemical and Environmental Engineering, Harbin University of Science and Technology, Harbin 150040 (China)] [Key Laboratory of Green Chemical Engineering and Technology of College of Heilongjiang Province, College of Chemical and Environmental Engineering, Harbin University of Science and Technology, Harbin 150040 (China); Ma, Huiyuan, E-mail: mahy017@nenu.edu.cn [Key Laboratory of Green Chemical Engineering and Technology of College of Heilongjiang Province, College of Chemical and Environmental Engineering, Harbin University of Science and Technology, Harbin 150040 (China)] [Key Laboratory of Green Chemical Engineering and Technology of College of Heilongjiang Province, College of Chemical and Environmental Engineering, Harbin University of Science and Technology, Harbin 150040 (China); Liu, Bo, E-mail: liubo200400@vip.sina.com [Key Laboratory of Green Chemical Engineering and Technology of College of Heilongjiang Province, College of Chemical and Environmental Engineering, Harbin University of Science and Technology, Harbin 150040 (China)] [Key Laboratory of Green Chemical Engineering and Technology of College of Heilongjiang Province, College of Chemical and Environmental Engineering, Harbin University of Science and Technology, Harbin 150040 (China); Li, Shaobin; Liu, Heng [Key Laboratory of Green Chemical Engineering and Technology of College of Heilongjiang Province, College of Chemical and Environmental Engineering, Harbin University of Science and Technology, Harbin 150040 (China)] [Key Laboratory of Green Chemical Engineering and Technology of College of Heilongjiang Province, College of Chemical and Environmental Engineering, Harbin University of Science and Technology, Harbin 150040 (China)

    2013-02-15

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

  10. Spectroscopic and structural studies of the Schiff base 3-methoxy-N-salicylidene-o-amino phenol complexes with some transition metal ions and their antibacterial, antifungal activities

    NASA Astrophysics Data System (ADS)

    Abo-Aly, M. M.; Salem, A. M.; Sayed, M. A.; Abdel Aziz, A. A.

    2015-02-01

    Spectroscopic (IR, Raman, NMR, UV-visible, and ESR), and structural studies of the ligand 3-methoxy-N-salicylidene-o-amino phenol (H2L) and its synthesized complexes with some transition metal ions (Mn(II), Co(II), Ni(II)), Cu(II) and Zn(II)) were recorded and analyzed. The magnetic properties and thermal gravimetric analysis (TGA and DTA) were also measured for the complexes. The metal complexes were found to have The structural formula ML?H2O and the metal ions Mn(II), Co(II), Ni(II)) and Zn(II) were found to form tetrahedral complexes with the ligand whereas Cu(II) formed a square planar one. Antimicrobial activity of the ligand and its complexes were also investigated and discussed.

  11. An unexpected cobalt(III) complex containing a Schiff base ligand: Synthesis, crystal structure, spectroscopic behavior, electrochemical property and SOD-like activity

    NASA Astrophysics Data System (ADS)

    Chai, Lan-Qin; Huang, Jiao-Jiao; Zhang, Hong-Song; Zhang, Yu-Li; Zhang, Jian-Yu; Li, Yao-Xin

    2014-10-01

    An unexpected mononuclear Co(III) complex, [Co(L2)2·(CH3COO)]·CH3OH (HL2 = 1-(2-{[(E)-3,5-dichloro-2-hydroxybenzylidene]amino}phenyl)ethanone oxime), has been synthesized via complexation of Co(II) acetate tetrahydrate with HL1 originally. The plausible reaction mechanism for the formation of quinazoline-type ligand was proposed. HL1 and its corresponding Co(III) complex were characterized by IR, as well as by elemental analysis and UV-vis spectroscopy. The crystal structure of the complex has been determined by single-crystal X-ray diffraction. Each complex links two other molecules into an infinite 1-D chain via intermolecular hydrogen bonding interactions. Moreover, the electrochemical properties of the cobalt(III) complex were studied by cyclic voltammetry and X-ray photoelectron spectrum (XPS). In addition, superoxide dismutase-like activities of HL1 and Co(III) complex were also investigated.

  12. An unexpected cobalt(III) complex containing a Schiff base ligand: Synthesis, crystal structure, spectroscopic behavior, electrochemical property and SOD-like activity.

    PubMed

    Chai, Lan-Qin; Huang, Jiao-Jiao; Zhang, Hong-Song; Zhang, Yu-Li; Zhang, Jian-Yu; Li, Yao-Xin

    2014-10-15

    An unexpected mononuclear Co(III) complex, [Co(L2)2·(CH3COO)]·CH3OH (HL2=1-(2-{[(E)-3,5-dichloro-2-hydroxybenzylidene]amino}phenyl)ethanone oxime), has been synthesized via complexation of Co(II) acetate tetrahydrate with HL1 originally. The plausible reaction mechanism for the formation of quinazoline-type ligand was proposed. HL1 and its corresponding Co(III) complex were characterized by IR, as well as by elemental analysis and UV-vis spectroscopy. The crystal structure of the complex has been determined by single-crystal X-ray diffraction. Each complex links two other molecules into an infinite 1-D chain via intermolecular hydrogen bonding interactions. Moreover, the electrochemical properties of the cobalt(III) complex were studied by cyclic voltammetry and X-ray photoelectron spectrum (XPS). In addition, superoxide dismutase-like activities of HL1 and Co(III) complex were also investigated. PMID:24840495

  13. Synthesis, spectral characterization, molecular modeling and in vitro antibacterial activity of complexes designed from O2, NO and NO donor Schiff-base ligand

    NASA Astrophysics Data System (ADS)

    El-Gammal, Ola A.; Abu El-Reash, G.; Ahmed, S. F.

    2015-01-01

    A new chelating agent, N?-(4-methoxybenzylidene)-2-oxo-2-(phenylamino)acetohydrazide (H2OMPH) and its complexes with Mn(II), Co(II), Ni(II), Cu(II), Zn(II), Hg(II) and U(IV)O22+ ions have been prepared and characterized by conventional techniques. The spectral data indicated that the ligand coordinates as neutral bidentate with Cu(II), Mn(II), U(IV)O22+ and Hg(II), neutral tridentate with Ni(II), mononegative tridentate with Co(II) and binegative tetradentate with Zn(II) ions. On basis of magnetic and electronic spectral data an octahedral geometry for Mn(II), Co(II) and Ni(II) complexes and a square planar geometry for Cu(II) complex have been proposed and confirmed by applying geometry optimization and conformational analysis. The protonation constants of H2OMPH and the stepwise stability constants of its complexes are calculated at 298, 308 and 318 k as well as their thermodynamic parameters. Also, the Kinetic parameters (Ea, A, ?H*, ?S* and ?G*) were determined for each thermal degradation stage of some complexes using Coats-Redfern and Horowitz-Metzger methods. Moreover, the ligand and some complexes were screened for in vitro antibacterial activity against Staphylococcus epidermalies (St. epid); Streptococcus pyagenies (Strp. py.) as Gram +ve bacteria and Escherichia coli (E. coli); Klebsiella spp. (kleb. spp.) as Gram -ve bacteria using inhibition zone diameter.

  14. [Study on synthesis and molecular spectra of the N-(2-hydroxy) naphthylmethyleneamino iron(III), cobalt(II) and copper(II) complexes].

    PubMed

    Kuang, D; Zhang, F

    1997-12-01

    The title complexes were synthesized via reaction of iron nitrate, cobalt acetate and copper acetate with the didentate O,N-donor Schiff bases in methanol solution. The electronic and infrared spectra of these complexes were measured and the major IR bands were assigned. PMID:15810239

  15. Synthesis of oxovanadium(IV) Schiff base complexes derived from C-substituted diamines and pyridoxal-5-phosphate as antitumor agents.

    PubMed

    Hazari, Puja Panwar; Pandey, Anand Kumar; Chaturvedi, Shubhra; Tiwari, Anjani Kumar; Chandna, Sudhir; Dwarakanath, Bilikere Srinivasarao; Mishra, Anil Kumar

    2012-02-01

    Oxovanadium (IV) complexes of N,N'-bispyridoxyl-5, 5'-bis (phosphate) ethylenediimine (L1) and N,N'-bis(pyridoxyl)-5,5'-bis(phosphate)-1''-(p-nitrobenzyl)ethylenediimine (L2) were synthesized by condensation of optically active C-substituted diamines and pyridoxal-5-phosphate. Oxovanadium (IV) complexes derived from L1 and L2 were evaluated as DNA cleavage agent (cleavage of supercoiled plasmid pBR322 DNA). Interestingly, both the oxovanadium (IV) complexes exhibited DNA nuclease activity, and the extent of oxidation of DNA by these vanadyl complexes was superior to VOSO(4) . The significant reduction in primary tumor and increased delay in tumor growth of 15 days was seen in the tumor regression analysis with oxovanadium (IV) complex of L1. With the preliminary studies performed with the pyridoxal-5-phosphate -based salen derivatives including the cytotoxicity and tumor regression, it is evident that the salen bifunctional chelating agent has obtained therapeutic potential if conjugated to a gene-specific targeting molecule for the oxidation of guanine residue. PMID:22023804

  16. Synthesis, Characterization and DNA-binding Properties of Three 3d Transition Metal Complexes of the Schiff Base Derived from Diethenetriamine with PMBP

    Microsoft Academic Search

    Yuan Wang; Zheng-Yin Yang

    2005-01-01

    A new ligand H2L, 1,7-di(1-phenyl-3-methyl-5-pyrazolone-4-benzylidene)diethenetriamine and its three transition metal complexes, ML · nH2O [M=Cu(II), n=2; M=Zn(II), n=0.5; M=Ni(II) (1), n=3] have been synthesized in anhydrous EtOH and characterized on the basis of elemental analyses, molar conductivities, i.r. spectra, u.v. spectra and thermal analyses. In addition, the DNA-binding properties of the ligand and its complexes have been investigated by absorption,

  17. Chiral dioxovanadium(V) Schiff base complexes of 1,2-diphenyl-1,2-diaminoethane and aromatic o-hydroxyaldehydes: Synthesis, characterization, catalytic properties and structure

    Microsoft Academic Search

    Grzegorz Romanowski; Edmund Kwiatkowski; Waldemar Nowicki; Marek Kwiatkowski; Tadeusz Lis

    2008-01-01

    A series of dioxovanadium(V) complexes of tridentate ligands obtained by monocondensation of chiral 1,2-diphenyl-1,2-diaminoethane and aromatic o-hydroxyaldehydes was synthesized. The complexes were characterized by spectroscopic methods in the solid state (IR) and in solution (UV–Vis, CD, 1H and 51V NMR). Single crystal X-ray analysis was performed with (VO2L·H2O)2, denoted as (4·H2O)2, where L is (S,S)-1-amino-2-{(2?-oxido-4?,6?-dimethoxyphenyl)methylene}amino-1,2-diphenylethane. Crystal structure analysis revealed that

  18. Synthesis and characterization of substituted Schiff-base ligands and their d(10) metal complexes: structure-induced luminescence tuning behaviors and applications in co-sensitized solar cells.

    PubMed

    Dong, Yu-Wei; Fan, Rui-Qing; Wang, Ping; Wei, Li-Guo; Wang, Xin-Ming; Zhang, Hui-Jie; Gao, Song; Yang, Yu-Lin; Wang, Yu-Lei

    2015-03-10

    Nine IIB group complexes, [ZnCl2] (), [CdCl2]2 (), [HgCl2] (), [ZnCl2] (), [CdCl2] (), [HgCl2] (), [ZnCl2] (), [CdCl2] () and [HgCl2] (), have been synthesized from the corresponding ortho-(6-methoxy-pyridyl)(CH[double bond, length as m-dash]NAr) (where Ar = 2,6-iPr2C6H3, ; 4-MeC6H4, ; 2-OMeC6H4, ) Schiff base and structurally characterized by elemental analysis, FT-IR, (1)H NMR and X-ray single-crystal analysis. Crystallographic studies reveal that the center metal of the complexes adopts a distorted tetrahedron geometry (except for and , which display square pyramidal geometry) and C-HCl hydrogen bonds and ?? stacking interactions contribute to three-dimensional supramolecular structures. The series of complexes exhibit tunable luminescence from blue, through green, to light yellow by varying the temperature (298 K and 77 K), both in solution and in the solid state. Moreover, the quantum yields range from 0.027 to 0.422, and decrease according to the order of the periodic table (Zn > Cd > Hg). These results indicate that the center atom of the complexes leads to the geometry differences and hence to the tunable luminescence properties. Because exhibited higher molar extinction coefficients and a distinct absorption region, they were employed as co-sensitizers in ruthenium dye N719-sensitized photoanodes to deliver light-electricity efficiency enhancement, being assembled with counter-electrodes and electrolyte to prepare ZnX/N719 (where ZnX = , and ) co-sensitized dye sensitized solar cell (DSSC) devices. The prepared co-absorbent could overcome the deficiency of N719 absorption in the low-wavelength region of the visible spectrum, and offset competitive visible-light absorption of I3(-). Application of these prepared complexes in N719-sensitized solar cells enhanced their performance by 10-36%, which indicated a potential application of these types of complexes in DSSCs. PMID:25597537

  19. Construction of a dinuclear silver(I) coordination complex with a Schiff base containing 4-amino-1,2,4-triazole ligands.

    PubMed

    Sun, Qiaozhen; Zheng, Feng; Sun, Xiaodan; Wang, Wei

    2009-01-01

    The new ligand 1-(1,2,4-triazol-4-ylimino-meth-yl)-2-naphthol (L) and the title silver(I) complex, namely bis-[?-1-(1,2,4-triazol-4-ylimino-meth-yl)-2-naphthol]bis-{[1-(1,2,4-triazol-4-yl-imino-meth-yl)-2-naphthol]silver(I)} dinitrate monohydrate, [Ag(2)(C(13)H(10)N(4)O)(4)](NO(3))(2)·H(2)O, were synthesized. Each silver center in the dimeric complex (related by an inversion centre) is coordinated by two bridging L ligands and one additional L ligand in a monodentate fashion, exhibiting a distorted trigonal-planar coordination. The discrete dimers are further linked through O-H?O hydrogen bonds and weak ?-? stacking inter-actions [the shortest atom-atom separation is ca 3.46?Å between the parallel stacking pairs]. Intramolecular O-H?N hydrogen bonds are also present. PMID:21582069

  20. Solid state isostructural behavior and quantified limiting substitution kinetics in Schiff-base bidentate ligand complexes fac-[Re(O,N-Bid)(CO)3(MeOH)](n).

    PubMed

    Brink, Alice; Visser, Hendrik G; Roodt, Andreas

    2014-12-01

    A range of N,O-donor atom salicylidene complexes of the type fac-[M(O,N-Bid)(CO)3(L)](n) (O,N-Bid = anionic N,O-bidentate ligands; L = neutral coordinated ligand) have been studied. The unique feature of the complexes which crystallize in a monoclinic isostructural space group for complexes containing methanol in the sixth position (L = MeOH) is highlighted. The reactivity and stability of the complexes were evaluated by rapid stopped-flow techniques, and the methanol substitution by a range of pyridine type ligands indicates significant activation by the N,O-salicylidene type of bidentate ligands as observed from the variation in the second-order rate constants. In particular, following the introduction of the sterically demanding and electron rich cyclohexyl salicylidene moiety on the bidentate ligand, novel limiting kinetic behavior is displayed by all entering ligands, thus enabling a systematic probe and manipulation of the limiting kinetic constants. Clear evidence of an interchange type of intimate mechanism for the methanol substitution is produced. The equilibrium and rate constants (25 °C) for the two steps in the dissociative interchange mechanism for methanol substitution in fac-[Re(Sal-Cy)(CO)3(MeOH)] (5) by the pyridine type ligands 3-chloropyridine, pyridine, 4-picoline, and DMAP are k3 (s(-1)), 40 ± 4, 13 ± 2, 10.4 ± 0.7, and 2.11 ± 0.09, and K2 (M(-1)), 0.13 ± 0.01, 0.21 ± 0.03, 0.26 ± 0.02, and 1.8 ± 0.1, respectively. PMID:25393647

  1. 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

  2. A potentiometric investigation of complex formation between some metal ions and biologically active quinazoline-4-3(H)-one Schiff's base

    NASA Astrophysics Data System (ADS)

    Shivakumar, K.; Shashidhar, S.; Halli, M. B.

    2007-10-01

    The proton dissociation constant of the ligand and the stability of the complexes of Co(II), Ni(II), Zn(II), Cd(II), Hg(II), Pb(II), Cu(II), Ba(II), Mg(II), Mn(II), Th(IV), and UO2(II) ions with 2-phenyl-3-(2'-hydroxy-5'-benzylidine)-quinazoline-4-(3H)-one [PBQ] were determined potentiometrically at 30 ± 0.1°C and ionic strengths of 0.025, 0.05, 0.10, 0.15 and 0.20 M NaNO3 in a 60:40 (v/v) ethanol-water medium. The proton-ligand and metal-ligand stability constants of the complexes were determined pH metrically by the Calvin-Bjerrum titration technique. The order of stability constants obeys the Irving-Rossotti rule. The negative values of ? G° suggest that the reactions are spontaneous.

  3. Zeolite encapsulated Ni(II)-Schiff-base complex: a novel size-selective electro-catalyst for the determination of the purity of stevioside.

    PubMed

    Avei, Mehdi Rashvand; Jafarian, Majid; Etezadi, Sedigheh; Gobal, Fereydoon; Khakali, Maryam; Rayati, Saeed; Mahjani, Mohammad Ghasem

    2013-04-15

    Ship-in-a-bottle complex of nickel(II) containing the ligand N,N'-bis(2,4-dihydroxyacetophenone)-2,2-dimethylpropandiimine (H2{salnptn(4-OH)2}) has been synthesized in zeolite Y. The characteristics of the encapsulated complex are identified by the methods of EDX, SEM, XRD, FT-IR and cyclic voltammetry. A catalytic effect in the electrochemical oxidation of glucose, fructose and sucrose, and a blocking effect in stevioside oxidation are demonstrated on the Ni(II){salnptn(4-OH)2}-Y/CPE. The effects of some parameters, such as potential scan rate and concentration of carbohydrates are investigated. The rate constants for the catalytic reaction (k') of carbohydrates are also obtained. The size-selective electro-catalyst shows a good linear dependency on carbohydrates' concentration in the range of 0.01-0.06 M with the detection limit of 6.4mM at the signal-to-noise ratio of 3. Furthermore, the modified electrode exhibits no interference with the simultaneous presence of stevioside. In brief, these results demonstrate that Ni(II){salnptn(4-OH)2}-Y composites have a great potential for synthesizing size-selective electrocatalysts for determining the purity of stevioside. PMID:23601865

  4. Hexa-, hepta- and dodeca-nuclear nickel(II) complexes of three Schiff-base ligands derived from 1,4-diformyl-2,3-dihydroxybenzene.

    PubMed

    Feltham, Humphrey L C; Clérac, Rodolphe; Brooker, Sally

    2009-04-28

    Three new closely-related diimine ligands, H(4), H(4) and H(4), were prepared by the condensation of 1,4-diformyl-2,3-dihydroxybenzene () with two equivalents of 2-aminoethanol, 3-aminopropanol or 2-aminophenol, respectively. Three polynuclear complexes, [Ni(II)(7)(H(2))(4)(OAc)(6)(H(2)O)(2)].5H(2)O (.5H(2)O), [Ni(II)(6)(H(2))(2)(OAc)(6)(micro-OMe)(2)(H(2)O)(2)].5H(2)O (.5H(2)O) and [Ni(II)(12)()(6)(MeOH)(7)(H(2)O)(3)].4H(2)O (.4H(2)O), were prepared by reaction of the appropriate ligand with 1.50/1.75, 1.75/3.00 or 2.00 equivalents, respectively, of nickel(II) acetate tetrahydrate, in methanol. The crystal structures of these complexes are very different to one another, despite what initially appear to be relatively minor ligand modifications. While [Ni(II)(7)(H(2))(4)(OAc)(6)(MeOH)(2)].7MeOH.4H(2)O possesses C(2) symmetry and has a 4:7 L:M ratio, [Ni(II)(6)(H(2))(2)(OAc)(6)(micro-OMe)(2)(MeOH)(2)].0.5MeOH.0.5H(2)O.Et(2)O and [Ni(II)(12)()(6)(MeOH)(6.5)(H(2)O)(3.5)].solvent have no internal symmetry and have L:M ratios of 2:6 and 6:12, respectively. Two of the four ligands in [Ni(II)(7)(H(2))(4)(OAc)(6)(MeOH)(2)] are in similar planes, whilst the two remaining ligands are near perpendicular to these planes. The six ligands in [Ni(II)(12)()(6)(MeOH)(6.5)(H(2)O)(3.5)] adopt an offset grid-like arrangement with eight of the twelve metal ions at the intersections of the perpendicular, offset, ligands. In contrast, [Ni(II)(6)(H(2))(2)(OAc)(6)(micro-OMe)(2)(MeOH)(2)] features an [Ni(II)(4)(OR)(4)] cubane core with wing tips of the remaining two nickel(II) ions. All three complexes were subsequently prepared in stoichiometric syntheses, in yields of 50% (.5H(2)O), 48% (.5H(2)O) and 62% (.4H(2)O). The magnetic properties of .5H(2)O, .5H(2)O, .4H(2)O are consistent with intra-complex antiferromagnetic coupling dominating overall, and therefore all three complexes display low spin ground states. PMID:19352524

  5. Novel dipodal Schiff base compounds: Synthesis, characterization and spectroscopic studies

    NASA Astrophysics Data System (ADS)

    Obali, Aslihan Yilmaz; Ucan, Halil Ismet

    2015-02-01

    Two novel dipodal Schiff base compounds 1,2-benzyloxy-bis-[2-(benzylideneamino)phenol, L1 and 1,2-benzyloxy-bis[3-(benzylideneamino)pyridine], L2 were synthesized. Their sensing actions were confirmed by UV-Vis absorbance and emission spectroscopic studies in presence of Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II), Sn(II), Cd(II) and Pb(II) in methanol medium (1 × 10-4 M). It was found that the dipodal compounds can selectively bind to Cu(II) and Pb(II) metal ions with a significant change in its emission and absorption spectra, while the addition of other metal ions (Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II), Sn(II), Cd(II) and Pb(II)) produces insignificant or minor changes. The host-guest complexes formed were determined by Job's plot method. As a chemosensor, L1 and L2 dipodal Schiff base compounds shows a specific selectivity towards Cu(II) and Pb(II) ions in according to all spectroscopic data.

  6. Synthesis, characterization, and preliminary in vitro studies of vanadium(IV) complexes with a Schiff base and thiosemicarbazones as mixed-ligands

    PubMed Central

    Lewis, Nerissa A.; Liu, Fange; Seymour, Luke; Magnusen, Anthony; Erves, Travis R.; Arca, Jessa Faye; Beckford, Floyd A.; Venkatraman, Ramaiyer; González-Sarrías, Antonio; Fronczek, Frank R.; VanDerveer, Don G.; Seeram, Navindra P.; Liu, Aimin; Jarrett, William L.; Holder, Alvin A.

    2013-01-01

    [VO(Sal-L-tryp)(H2O)] 1 (where sal-L-tryp = N-salicylidene-L-tryptophanate) was used as a precursor to produce the novel complexes, [VO(Sal-L-tryp)(MeATSC)].1.5C2H5OH 2 (where MeATSC = 9-Anthraldehyde-N(4)-methylthiosemicarbazone), [VO(Sal-L-tryp)(N-Ethhymethohcarbthio)].H2O 3 (where N-Ethhymethohcarbthio = (E)-N-ethyl-2-(4-hydroxy-3-methoxybenzylidene)hydrazinecarbothioamide), and [VO(Sal-L-tryp)(acetylethTSC)].C2H5OH 4 (where acetylethTSC = (E)-N-ethyl-2-(1-(thiazol-2-yl)ethylidene)hydrazinecarbothioamide), by reaction with the respective thiosemicarbazone. The chemical and structural properties of these ligands and complexes were characterised by elemental analysis, ESI MS, FT-IR, UV-visible, ESR, 1H and 13C NMR spectroscopy, and X-ray crystallography. DMSO and DMSO-d6 solutions of compounds 1-4 were oxidised in air to produce vanadium(V) species which were verified by ESI MS and 51V NMR spectroscopy. Anti-cancer properties of compounds 2-4 were examined with three colon cancer cell lines, HTC-116, Caco-2, and HT-29, and also with non-cancerous colonic myofibroblasts, CCD18-Co. Compounds 2-3 exhibited less inhibitory effects in the CCD-18Co cells, indicating a possible cytotoxic selectivity towards colon cancer cells. In general, those compounds which exhibited anti-proliferative activity on cancer cells, but did not affect non-cancerous cells, may have a potential in chemotherapy. PMID:23904789

  7. 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.

  8. Schiff-based bipyridine ligands. Unusual coordination features and mesomorphic behaviour

    Microsoft Academic Search

    Raymond Ziessel

    2001-01-01

    Recent investigations from our laboratory have described compelling experimental evidence that Schiff-based pyridine, bipyridine (bipy), terpyridine (terpy), phenanthroline (phen), naphthyridine (naphthy) and pyridine–pyridazine (pyridaz) ligands exhibit a rich coordination chemistry towards transition metal complexes providing unusual coordination modes. This is well illustrated with bipy and phen frameworks which exhibit a bridging type of coordination compared to the classical chelating behaviour.

  9. IR and ESR studies on some dimeric copper(II) complexes

    NASA Astrophysics Data System (ADS)

    Cozar, O.; David, L.; Chi?, V.; Damian, G.; Todic?, M.; Agut, C.

    2001-05-01

    The copper(II) p-chlorobenzoates [Cu 2R 4·CH 3OH·2H 2O] (I) and [Cu 2R 4·CH 3COCH 3·2H 2O] (II) dimeric complexes, where R=( p-ClC 6H 4CO 2), as well as their monomeric species which occur at 77 K have been investigated by IR and ESR spectroscopy. The coordination of the copper(II) ions at the carboxylic -COO group arises from the appearance in the IR spectra of studied complexes of the stretching vibration ?(Cu-O) at 475 cm -1 and the combination frequencies ?(Cu-O)+ ?ring at 690 cm -1, ?(Cu-O)+ ?(O-C?O) at 770-800 cm -1. The room temperature powder ESR spectra of the both copper(II) complexes correspond to a randomly oriented triplet state ( S=1) for coupled Cu(II) ions with short Cu-Cu distance (˜2.64 Å). The 77 K spectra indicate the coexistence of monomeric and dimeric species. The complex (I) presents two monomeric magnetic nonequivalent species, one (I') with square-planar local symmetry D4h(g ?=2.301, g ?=2.067, A ?=174×10 -4 cm-1, A ?=21.4×10 -4 cm-1) and the other (I?) with tetragonal-octahedral O h distorted symmetry due to the coordination of two water molecules along the Oz axis of Cu 2+ ion (g ?=2.327, g ?=2.046, A ?=162×10 -4 cm-1, A ?=43×10 -4 cm-1). Only the tetragonal-octahedral distorted species ( g?=2.324, g?=2.044, A ?=165×10 -4 cm-1, A?=43×10 -4cm -1) occurs in the complex (II).

  10. Spectroscopic studies on Solvatochromism of mixed-chelate copper(II) complexes using MLR technique

    NASA Astrophysics Data System (ADS)

    Golchoubian, Hamid; Moayyedi, Golasa; Fazilati, Hakimeh

    2012-01-01

    Mixed-chelate copper(II) complexes with a general formula [Cu(acac)(diamine)]X where acac = acetylacetonate ion, diamine = N,N-dimethyl,N'-benzyl-1,2-diaminoethane and X = BPh 4-, PF 6-, ClO 4- and BF 4- have been prepared. The complexes were characterized on the basis of elemental analysis, molar conductance, UV-vis and IR spectroscopies. The complexes are solvatochromic and their solvatochromism were investigated by visible spectroscopy. All complexes demonstrated the positive solvatochromism and among the complexes [Cu(acac)(diamine)]BPh 4·H 2O showed the highest ? ?max value. To explore the mechanism of interaction between solvent molecules and the complexes, different solvent parameters such as DN, AN, ? and ? using multiple linear regression (MLR) method were employed. The statistical results suggested that the DN parameter of the solvent plays a dominate contribution to the shift of the d-d absorption band of the complexes.

  11. Synthesis, spectral characterization, structural investigation and antimicrobial studies of mononuclear Cu(II), Ni(II), Co(II), Zn(II) and Cd(II) complexes of a new potentially hexadentate N2O4 Schiff base ligand derived from salicylaldehyde

    NASA Astrophysics Data System (ADS)

    Keypour, Hassan; Shayesteh, Maryam; Rezaeivala, Majid; Chalabian, Firoozeh; Elerman, Yalcin; Buyukgungor, Orhan

    2013-01-01

    A new potentially hexadentate N2O4 Schiff base ligand, H2L derived from condensation reaction of an aromatic diamine and salicylaldehyde, and its metal complexes were characterized by elemental analyses, IR, UV-Vis, EI-MS, 1H and 13C NMR spectra, as well as conductance measurements. It has been originated that the Schiff base ligand with Cu(II), Ni(II), Co(II), Cd(II) and Zn(II) ions form mononuclear complexes on 1:1 (metal:ligand) stoichiometry. The conductivity data confirm the non-electrolytic nature of the complexes. Also the crystal structures of the complexes [ZnL] and [CoL] have also been determined by using X-ray crystallographic technique. The Zn(II) and Co(II) complexes show a tetrahedral configuration. Electronic absorption spectra of the Cu(II) and Ni(II) complexes suggest a square-planar geometry around the central metal ion. The synthesized compounds have antibacterial activity against the three Gram-positive bacteria: Bacillus cereus, Enterococcus faecalis and Listeria monocytogenes and also against the three Gram-negative bacteria: Salmonella paraB, Citrobacter freundii and Enterobacter aerogenes. The results showed that in some cases the antibacterial activity of complexes were more than nalidixic acid and amoxicillin as standards.

  12. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2014-06-01

    Two new mixed-ligand copper(II) complexes, [Cu(dipn)(Nsbnd N)]Br2(1-2) [dipn = dipropylenetriamine, Nsbnd N = ethylenediamine (en) (1) and propylenediamine (pn) (2)], have been synthesized. These complexes were characterized by spectroscopic and thermal techniques. Crystal structure for 2 shows a distorted trigonal-bipyramidal geometry around Cu(II) ion with one solvate water molecule. Antimicrobial and antiproliferative assays were conducted to evaluate the biological activities of these complexes. The complexes exhibit a promising antimicrobial effect against an array of microbes at 200 ?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).

  14. Synthesis and Characterization of Novel Ruthenium(II) Chelates with Some Schiff Bases Derived from 4Benzoyl3Methyl1Phenyl2-Pyrazolin-5One and Sulpha Drugs

    Microsoft Academic Search

    R. C. Maurya; D. D. Mishra; N. Sumita Rao; N. Nageswara Rao

    1994-01-01

    Three novel ruthenium(II) complexes with the neutral bidentate O,N-donor Schiff bases L-L (where L-L is the Schiff base prepared from sulphadiazine, sulphamerazine or sulphamethazine and 4-benzoyl-3-methyl-1-phenyl-2-pyrazolin-5-one) have been synthesized by the interaction of K2RuCl5. H2O and the Schiff bases in aqueous ethanol. The complexes, which have been characterized on the basis of elemental analyses, molar conductances, cyclic voltammetry, infrared, electronic

  15. 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.

  16. Synthesis, characterization and antibacterial activity of some new complexes of Cu(II), Ni(II), VO(II), Mn(II) with Schiff base derived from 4-amino-2,3-dimethyl-1-phenyl-3-pyrazolin-5-one

    Microsoft Academic Search

    Tudor Rosu; Elena Pahontu; Catalin Maxim; Rodica Georgescu; Nicolae Stanica; Gabriela Laura Almajan; Aurelian Gulea

    2010-01-01

    Coordination compounds of Cu(II), VO(II), Ni(II), and Mn(II) with the Schiff base obtained through the condensation of 4-amino-2,3-dimethyl-1-phenyl-3-pyrazolin-5-one with 3-formyl-6-methyl-chromone were synthesized. The characterization of the newly formed compounds was done by 1H NMR, UV–Vis, IR, ESR spectroscopy, elemental analysis and molar electric conductibility. The crystal structure of 1-phenyl-2,3-dimethyl-4-(N-3-formyl-6-methyl-chromone)-3-pyrazolin-5-one (HL) has been determined by X-ray diffraction studies, as well as

  17. Syntheses, structures and electrochemical properties of two co-crystal copper(II) melamine complexes

    NASA Astrophysics Data System (ADS)

    Xu, Li-Feng; Chen, Xiao-Li; Hu, Huai-Ming; Wang, Bao-Cheng

    2008-12-01

    Two new co-crystal copper(II) melamine complexes, [Cu(HBA) 2(MA) 2] [Cu(HBA) 2] ( 1) and [Cu 2(OAc) 4(MA)·(H 2O)] 2[Cu(HPE) 2] ( 2), MA, melamine; HBA, 2-hydroxybenzaldehyde; HPE, 1-(2-hydroxyphenyl)ethanone, have been synthesized and characterized by elemental analysis, IR and single crystal X-ray diffraction. Crystal structural analysis reveals that 1 and 2 all are co-crystal complexes and composed of two neutral coordination units. In 1, two mononuclear units adopt square planar and distorted octahedral coordination environments, respectively. In 2, one is a mononuclear unit with a square planar geometry and the other is a dinuclear unit with a paddle wheel structure in which the apical positions are rarely occupied by two different donor ligands. The 2D supramolecular structures are formed through strong hydrogen bonds with different modes. The electrochemical behaviors of complexes 1 and 2 were investigated.

  18. 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.

  19. Synthetic, Structural, and Biochemical Studies of Organotin(IV) With Schiff Bases Having Nitrogen and Sulphur Donor Ligands

    PubMed Central

    Singh, Har Lal; Varshney, A. K.

    2006-01-01

    Three bidentate Schiff bases having nitrogen and sulphur donor sequences were prepared by condensing S-benzyldithiocarbazate (NH2NHCS2CH2C6H5) with heterocyclic aldehydes. The reaction of diphenyltin dichloride with Schiff bases leads to the formation of a new series of organotin(IV) complexes. An attempt has been made to prove their structures on the basis of elemental analyses, conductance measurements, molecular weights determinations, UV, infrared, and multinuclear magnetic resonance (1H, 13C, and 119Sn) spectral studies. Organotin(IV) complexes were five- and six-coordinate. Schiff bases and their corresponding organotin complexes have also been screened for their antibacterial and antifungal activities and found to be quite active in this respect. PMID:17497003

  20. Correlation of Electronic and Geometric Structure in Mononuclear Copper(II) Superoxide Complexes

    PubMed Central

    Ginsbach, Jake W.; Peterson, Ryan L.; Cowley, Ryan E.; Karlin, Kenneth D.; Solomon, Edward I.

    2013-01-01

    The geometry of mononuclear copper(II) superoxide complexes has been shown to determine their ground state where side-on bonding leads to a singlet ground state and end-on complexes have triplet ground states. In apparent contrast to this trend, the recently synthesized (HIPT3tren)CuII–O2•? (1) was proposed to have an end-on geometry and a singlet ground state. However, re-examination of 1 with resonance Raman (rR), magnetic circular dichroism (MCD), and 2H NMR spectroscopy indicates that 1 is in fact an end-on superoxide species with a triplet ground state that results from the single CuII–O2•? bonding interaction being weaker than the spin pairing energy. PMID:24164429

  1. Synthesis, spectroscopic studies and structures of square-planar nickel(II) and copper(II) complexes derived from 2-{(Z)-[furan-2-ylmethyl]imino]methyl}-6-methoxyphenol.

    PubMed

    Unver, Hüseyin; Hayvali, Zeliha

    2010-02-01

    Two new nickel(II) [Ni(L)(2)] and copper(II) [Cu(L)(2)] complexes have been synthesized with bidentate NO donor Schiff base ligand (2-{(Z)-[furan-2-ylmethyl]imino]methyl}-6-methoxyphenol) (HL) and both complexes Ni(L)(2) and Cu(L)(2) have been characterized by elemental analyses, IR, UV-vis, (1)H, (13)C NMR, mass spectroscopy and room temperature magnetic susceptibility measurement. The tautomeric equilibria (phenol-imine, O-H...N and keto-amine, O...H-N forms) have been systemetically studied by using UV-vis absorption spectra for the ligand HL. The UV-vis spectra of this ligand HL were recorded and commented in polar, non-polar, acidic and basic media. The crystal structures of these complexes have also been determined by using X-ray crystallographic techniques. The complexes Ni(L)(2) and Cu(L)(2) crystallize in the monoclinic space group P2(1)/n and P2(1)/c with unit cell parameters: a=10.4552(3)A and 12.1667(4)A, b=8.0121(3)A and 10.4792(3)A, c=13.9625(4)A and 129.6616(3)A, V=1155.22(6)A(3) and 1155.22(6)A(3), D(x)=1.493 and 1.476 g cm(-3) and Z=2 and 2, respectively. The crystal structures were solved by direct methods and refined by full-matrix least squares to a find R=0.0377 and 0.0336 of for 2340 and 2402 observed reflections, respectively. PMID:20047854

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

    NASA Astrophysics Data System (ADS)

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

    2011-02-01

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

  3. Two Copper(II) Complexes with Mono-Oxime Chelating Ligands: Synthesis, Crystal Structure, and Substituent Effect

    Microsoft Academic Search

    Wen-Kui Dong; Jian Yao; Yin-Xia Sun; Li Li; Jian-Chao Wu

    2010-01-01

    Two new complexes, [Cu(L)2] (1) and [Cu(L)2(H2O)]·CH3OH (2), have been synthesized via the complexation of copper(II) acetate monohydrate with two mono-oxime chelating ligands (HL: 4-[(Methoxyimino)(phenyl)methyl]-5-methyl-2-phenyl-1H- pyrazol-3(2H)-one and HL: 4-[(Ethoxyimino)(phenyl)methyl]-5-methyl-2-phenyl-1H-pyrazol-3(2H)-one), respectively. X-ray crystal structure determination of the two complexes show that complex 1 consists of one copper(II) ion, two bidentate (L) units, and the copper atom of complex 1 has a

  4. Recent pharmacological advancements in schiff bases: a review.

    PubMed

    Murtaza, Ghulam; Mumtaz, Amara; Khan, Farhan Ahmed; Ahmad, Saeed; Azhar, Saira; Khan, Shujaat Ali; Najam-Ul-Haq, Muhammad; Atif, Muhammad; Khan, Shujaat Ali; Maalik, Aneela; Azhar, Saira; Murtaza, Ghulam

    2014-01-01

    Schiff bases are the biologically privileged scaffolds in organic chemistry, commonly synthesized from the condensation reaction of carbonyl functional group with amines. Naturally occurring and synthetically prepared Schiff bases are active molecules with many pharmacological activities like antibacterial, anti-cancer, anti-fungal, anti-malarial, antioxidant and many more. This review article summarizes pharmacological developments in the recent few years and gives a brief overview of their therapeutic potential. PMID:25272879

  5. A novel Schiff-base as a Cu(II) ion fluorescent sensor in aqueous solution

    NASA Astrophysics Data System (ADS)

    Gündüz, Z. Yurtman; Gündüz, C.; Özp?nar, C.; Urucu, O. Ayd?n

    2015-02-01

    A new fluorescent Cu(II) sensor (L) obtained from the Schiff base of 5,5?-methylene-bis-salicylaldehyde with amidol (2,4-diaminophenol) was synthesized and characterized by FT-IR, MS, 1H NMR, 13C NMR techniques. In the presence of pH 6.5 (KHPO4-Na2HPO4) buffer solutions, copper reacted with L to form a stable 2:1 complex. Fluorescence spectroscopic study showed that Schiff base is highly sensitive towards Cu(II) over other metal ions (K+, Na+, Al3+, Ni2+, Co2+, Fe3+, Zn2+, Pb2+) in DMSO/H2O (30%, v/v). The sensor L was successfully applied to the determination of copper in standard reference material. The structural properties and molecular orbitals of the complex formed between L and Cu2+ ions were also investigated using quantum chemical computations.

  6. Determination of chlorogenic acid in coffee using a biomimetic sensor based on a new tetranuclear copper(II) complex

    Microsoft Academic Search

    Mirella Lucas de Carvalho; Murilo Santhiago; Rosely A. Peralta; Ademir Neves; Gustavo Amadeu Micke; Iolanda Cruz Vieira

    2008-01-01

    A new tetranuclear copper(II) complex which mimics the active site of catechol oxidase was synthesized and characterized by IR, CHN, electronic spectroscopic and 1H NMR methods. The title complex [Cu2(?-OH)(bpbpmp-NO2)]2[ClO4]2 was employed in the construction of a novel biomimetic sensor and used in the determination of chlorogenic acid by square wave voltammetry. The performance and optimization of the resulting biomimetic

  7. Synthesis and Structure of a New Trinuclear Copper(II) Complex with 5Phenyl Pyrazole3Carboxylic Acid as Ligand

    Microsoft Academic Search

    Yong-Heng Xing; Guang-Hua Zhou; Yue An; Xiao-Qing Zeng; Mao-Fa Ge

    2008-01-01

    A new copper(II) complex of general formula Na2(Cu3L4) · 2H2O · 2CH3OH (L = 5-phenyl pyrazole-3-carboxylic acid) has been newly obtained by the reaction of copper chloride with 5-phenyl pyrazole-3-carboxylic acid in methanol in the presence of NaOH at room temperature. X-ray diffraction analysis of the crystal structure reveals that the complex is a trinuclear crystal structure that consists of

  8. Schiff's Bases and Crown Ethers as Supramolecular Sensing Materials in the Construction of Potentiometric Membrane Sensors

    PubMed Central

    Faridbod, Farnoush; Ganjali, Mohammad Reza; Dinarvand, Rassoul; Norouzi, Parviz; Riahi, Siavash

    2008-01-01

    Ionophore incorporated PVC membrane sensors are well-established analytical tools routinely used for the selective and direct measurement of a wide variety of different ions in complex biological and environmental samples. Potentiometric sensors have some outstanding advantages including simple design and operation, wide linear dynamic range, relatively fast response and rational selectivity. The vital component of such plasticized PVC members is the ionophore involved, defining the selectivity of the electrodes' complex formation. Molecular recognition causes the formation of many different supramolecules. Different types of supramolecules, like calixarenes, cyclodextrins and podands, have been used as a sensing material in the construction of ion selective sensors. Schiff's bases and crown ethers, which feature prominently in supramolecular chemistry, can be used as sensing materials in the construction of potentiometric ion selective electrodes. Up to now, more than 200 potentiometric membrane sensors for cations and anions based on Schiff's bases and crown ethers have been reported. In this review cation binding and anion complexes will be described. Liquid membrane sensors based on Schiff's bases and crown ethers will then be discussed.

  9. Ligating behaviour of Schiff base ligands derived from heterocyclic ?-diketone and ethanol or propanol amine with oxovanadium (IV) metal ion

    Microsoft Academic Search

    B. T. Thaker; R. S. Barvalia

    2009-01-01

    Synthesis and evaluation of six new oxovanadium (IV) complexes, formed by the interaction of vanadyl sulphate pentahydrate and the Schiff base, viz.; (HL1)–(HL3) and (HL4)–(HL6) such as 5-hydroxy-3-methyl-1(2-chloro)phenyl-1H-pyrazolone-4-carbaldehyde (I), 5-hydroxy-3-methyl-1(3-chloro)phenyl-1H-pyrazolone-4-carbaldehyde (II) and 5-hydroxy-3-methyl-1(3-sulphoamido)phenyl-1H-pyrazolone-4-carbaldehyde (III) with ethanol amine and propanol amine, respectively, in aqueous ethanol medium. The ligands and their Schiff base ligands have been characterized by elemental analyses, IR and

  10. Synthesis and structural characterization of two copper(II) complexes constructed from copper(II) thenoyltrifluoroacetonate and the rigid imidazolyl-based ligands

    NASA Astrophysics Data System (ADS)

    Wang, G.-F.; Sun, S.-W.; Han, Q.-P.; Zhang, W.-C.; Sun, H.; Song, S.-F.; Cui, G.-H.

    2014-12-01

    Two copper(II) complexes, Cu( tta)2( L 1 )2 ( 1), Cu( tta)2( L 2 ) ( 2) (where L 1 = 4-imidazolylbenzaldehyde, L 2 = ( E)-3-(4-(1 H-imidazol-1-yl)phenyl)-1-(4-methoxyphenyl)prop-2-en-1-one) have been synthesized from the reaction of Cu( tta)2 with L 1 and L 2 in the methanol medium, respectively. Their structures have been characterized by IR, elemental analyses and single-crystal X-ray diffraction. The copper (II) ion of 1 is in a distorted octahedral environment, in which the donor atoms are provided by two oxygen atoms of the two tta ligands and two nitrogen atoms of L 1 ligands, while that of 2 is in a distorted square-pyramidal environment with three O atoms of the two tta ligands and one N atom of imidazole ligand L 2 lying at the base.

  11. 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.

  12. 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.

  13. Tautomeric design of ortho-hydroxyheterocyclic Schiff bases

    NASA Astrophysics Data System (ADS)

    Kwocz, Agnieszka; Kochel, Andrzej; Chudoba, Dorota; Filarowski, Aleksander

    2015-01-01

    The article reports on the synthesis and crystallographic and theoretical studies on various heterocyclic derivatives of ortho-hydroxy Schiff bases. The prevailing of one of the two (enolimine - OH and ketoamine - NH) tautomeric forms has been stated in studied compounds depending on the substitutes in heterocyclic formation, the nitrogen and carbon atoms of the imine group. A specific situation has been shown in (1E)-1-(5-chloro-2-hydroxy-3-nitrophenyl)ethanone oxime compound. The potentials on the proton transfer of the hydrogen bridges in these compounds have been found out. Grounded on the obtained potential curves the influence of the protonation on nitrogen in the pyridoxal derivative of the studied ortho-hydroxy Schiff bases has been analysed. The most efficient method of the impact (by means of various substitutes) on the intramolecular tautomeric equilibrium in ortho-hydroxy Schiff bases has been presented.

  14. Potentially cytotoxic new copper(II) hydrazone complexes: synthesis, crystal structure and biological properties.

    PubMed

    Alagesan, Mani; Bhuvanesh, Nattamai S P; Dharmaraj, Nallasamy

    2013-05-21

    A new set of penta-coordinated copper(II) hydrazone complexes containing solvated methanol were synthesized by reacting the hydrazone ligands, 2-acetylpyridine benzoyl hydrazone (HL1) and 2-acetylpyridine thiophene-2-carboxylic acid hydrazone (HL2), with [CuCl2(DMSO)2] and characterized by different spectral methods. Single crystal X-ray diffraction studies of the complexes revealed that both of them, [CuCl(L1)(MeOH)] (1) and [CuCl(L2)(MeOH)] (2), have square pyramidal geometry around the cupric ion, in which the hydrazone is coordinated through NNO atoms along with a molecule of methanol in the apical position. Interaction of the ligands HL1 and HL2 along with the corresponding copper complexes 1 and 2 with calf thymus DNA (CT-DNA) has been estimated by absorption and emission titration methods which revealed that the compounds interacted with CT-DNA through intercalation. Binding of the compounds, i.e., free ligands and complexes (1) and (2) with bovine serum albumin (BSA) protein investigated using UV-visible, fluorescence and synchronous fluorescence spectroscopic methods indicated that there occurred strong binding of copper complexes to BSA over the ligands. Further, the cytotoxicity of the compounds examined in vitro on a panel of cancerous cell lines such as a human cervical cancer cell line (HeLa), a pancreatic cancer cell line (PANC-1), an Ehrlich ascites cancer cell line (EAC) and Dalton's lymphoma ascitic cancer cells (DLA) and a normal mouse embryonic fibroblasts cell line (NIH3) demonstrated that the complexes 1 and 2 possessed superior cytotoxicity than that of well-known commercial anticancer drug cisplatin to the tumor cells but are less toxic to the normal cell line and have emerged as potential candidates for further studies. PMID:23529726

  15. 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.

  16. Synthesis of Chromium(III) Chelates of Some Newly Synthesized Heterocyclic Teiradentate Schiff Bases

    Microsoft Academic Search

    D. S. Raj; P. C. Shah; J. R. Shah

    1992-01-01

    Eight new heterocyclic tetradentate Schiff bases were synthesized by reaction of 4-acetyl-1-phenyl-3-methyl-2-pyrazolin-5-one or 4-acetyl-1-(3?-chlorophenyl)-3-methyl-2-pyrazolin-5-one with ethylenediamine, o-phenylenediamine, m-phenylenedia-mine or p-phenylenediamine and chromium(Hl) complexes prepared.' The complexes were characterized on the basis of elemental analysis, conductance, TGA, magnetic measurements, infrared and electronic spectral studies. The chelates were of octahedral structure and most of them have magnetic moments close to the spin

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

    NASA Astrophysics Data System (ADS)

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

    2012-07-01

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

  18. 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

  19. Spectroscopic and magnetic studies of some copper(II) and chromium(III) complexes with dithiophosphonates as ligands

    NASA Astrophysics Data System (ADS)

    Haiduc, I.; David, L.; Cozar, O.; Micu-Semeniuc, R.; Mezei, G.; Armenean, M.

    1999-05-01

    Cu(II)-bis[4-ethoxyphenyl- O-alkyl]-dithiophosphonate and Cr(III)-tris[4-ethoxyphenyl- O-alkyl]-dithiophosphonate complexes (alkyl=methyl, ethyl, isopropyl) were prepared and studied by magnetic measurements, and electronic, IR and EPR spectroscopic studies. The valence vibrations of the PS 2 group show that this group coordinates isobidentate. The electronic spectra of copper(II) complexes display two weak bands at 15?200 and 18?500 cm -1, ( 2B 1g? 2A 1g and 2B 1g? 2E g) and an intense band at 23?000 cm -1 (L?M charge-transfer). The powder EPR spectra of Cu (II) complexes are typical for square-planar monomeric species and present hyperfine and superhyperfine structure. These results suggest that the copper(II) complexes have D 4h symmetry. Two bands were observed in the UV-Vis spectra of the chromium complexes at 14?320 and 18?640 cm -1 ( 4A 2g(F)? 4T 2g(F) and 4A 2g(F)? 4T 1g(F)). The EPR bands of the Cr(III) complexes may be attributed to isolated metallic ions in pseudoocthaedral surroundings and to Cr(III) ions coupled by dipole-dipole interaction.

  20. Synthesis, Characterization, and Bioactivity of Schiff Bases and Their Cd(2+), Zn(2+), Cu(2+), and Ni(2+) Complexes Derived from Chloroacetophenone Isomers with S-Benzyldithiocarbazate and the X-Ray Crystal Structure of S-Benzyl- ? -N-(4-chlorophenyl)methylenedithiocarbazate.

    PubMed

    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 Cd(2+), Zn(2+), Cu(2+), and Ni(2+). 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

  1. 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

  2. Crystal structures of copper(II) nitrate, copper(II) chloride, and copper(II) perchlorate complexes with 2-formylpyridine semicarbazone

    SciTech Connect

    Chumakov, Yu. M. [Academy of Sciences of Moldova, Institute of Applied Physics (Moldova, Republic of); Tsapkov, V. I. [State University of Moldova (Moldova, Republic of); Antosyak, B. Ya. [Academy of Sciences of Moldova, Institute of Applied Physics (Moldova, Republic of); Bairac, N. N. [State University of Moldova (Moldova, Republic of); Simonov, Yu. A., E-mail: simonov.xray@phys.asm.md [Academy of Sciences of Moldova, Institute of Applied Physics (Moldova, Republic of); Bocelli, G. [National Research Council (IMEM-CNR), Institute of Materials for Electronics and Magnetism (Italy); Pahontu, E. [University of Medicine and Pharmacy (Romania); Gulea, A. P. [State University of Moldova (Moldova, Republic of)

    2009-05-15

    Compounds dinitrato(2-formylpyridinesemicarbazone)copper (I), dichloro(2-formylpyridinesemicarbazone) copper hemihydrate (II), and bis(2-formylpyridinesemicarbazone)copper(2+) perchlorate hydrate (III) are synthesized and their crystal structures are determined. In compounds I-III, the neutral 2-formylpyridine semicarbazone molecule (L) is tridentately attached to the copper atom via the N,N,O set of donor atoms. In compounds I and II, the Cu: L ratio is equal to 1: 1, whereas, in III, it is 1: 2. In complex I, the coordination sphere of the copper atom includes two nitrate ions with different structural functions in addition to the L ligand. The structure is built as a one-dimensional polymer in which the NO{sub 3} bidentate group fulfills a bridging function. The coordination polyhedron of the copper(2+) atom can be considered a distorted tetragonal bipyramid (4 + 1 + 1). Compound II has an ionic structure in which the main element is the [CuLCl{sub 2} . Cu(H{sub 2}O)LCl]{sup +} dimer. In the dimer, the copper atoms are linked via one of the {mu}{sub 2}-bridging chlorine atoms. The coordination polyhedra of the central atoms of the Cu(H{sub 2})LCl and CuLCl{sub 2} complex fragments are tetragonal bipyramid and tetragonal pyramid, respectively. In compound III, the copper atom is octahedrally surrounded by two L ligands in the mer configuration.

  3. Thermodynamics of the formation of complexes of copper(II) ions and glycylglycine in aqueous solutions at 298 K according to calorimetry data

    NASA Astrophysics Data System (ADS)

    Kochergina, L. A.; Emel'yanov, A. V.

    2015-04-01

    Heat effects of the interaction between glycylglycine and copper(II) nitrate solutions are measured by direct calorimetry at a [metal] : [ligand] ratio of 1 : 5 and at different pH values of the solution. The measurements are made at a temperature of 298.15 K and ionic strengths of 0.25, 0.50, and 0.75. KNO3 is used as a background electrolyte. The thermodynamic characteristics of complex formation by the peptide and copper(II) ions in aqueous solutions are determined. Standard enthalpies of the formation of complex particles in aqueous solutions are calculated.

  4. Template-directed synthesis of macrocyclic copper(II) complexes of diazacyclam, 1,3,6,10,12,15-hexaazatricyclo[13.3.1.1]eicosane

    Microsoft Academic Search

    Mohammad Hakimi; Keyvan Moeini; Zahra Mardani; Manuel A. Fernandes; Fabian Mohr; Esther Schuh

    2012-01-01

    Template reaction of copper(II) nitrate with N-(2-aminoethyl)-1,3-diaminopropane and formaldehyde yields a macrocyclic copper(II) complex of 1,3,6,10,12,15-hexaazatricyclo[13.3.1.1]eicosane (L), [CuL(NO3)2] (1). Replacement of nitrate with perchlorate gives [CuL(ClO4)2] (2). These complexes have been characterized by FT-IR and Raman spectroscopies, electronic absorption, cyclic voltammetry, and X-ray crystallography. The crystal structure of 1 shows that copper has distorted octahedral geometry with two secondary and

  5. Spectroscopic studies of some oxygen-bonded copper(II) ?-diketonate complexes

    NASA Astrophysics Data System (ADS)

    David, L.; Cr?ciun, C.; Cozar, O.; Chi?, V.; Agut, C.; Rusu, D.; Rusu, M.

    2001-05-01

    The copper(II) ?-diketonate complexes Cu(L 1) 2, Cu(L 2) 2, Cu(L 3) 2, where L 1=H 3C-CO-CH-CO-CH 3, L 2=H 5C 6-CO-CH-CO-C 6H 5, L 3=H 5C 6-CO-CH-CO-OC 2H 5, were prepared and investigated by spectroscopic (FT-IR, UV-VIS, EPR) methods. The coordination of the Cu(II) ion to the oxygen atoms of two ?-diketonate molecules is observed by the shift of the ? s( C? C), ? s( C? O) and ? as( C? O) stretching vibrations in the FT-IR spectra of the complexes with reference to those of the ligands. In the visible electronic spectra of the Cu(II) ?-diketonate complexes the very broad absorption bands of B 1g?B 2g and B 1g?E g transitions appear at ?13,500, 16,070 cm -1 for Cu(L 1) 2, 14,500, 16,630 cm -1 for Cu(L 2) 2 and 13,075, 15,410 cm -1 for Cu(L 3) 2. Besides the bands of the intraligand ?-? ? transitions (29,000-42,000 cm -1) of ?-diketonates, the UV spectra of the Cu(II)-complexes contain the L ??M d bands (45,500-46,100 cm -1). The powder EPR spectrum of the Cu(L 1) 2 complex is quasi-isotropic and asymmetric ( g?=2.160, g?=2.050), that of Cu(L 2) 2 is axial ( g?=2.216, g?=2.045), and typical for square-planar compounds and that of Cu(L 3) 2 is rhombic, with g1=2.167, g2=2.082 and g3=2.004. The low gyromagnetic factors arise from the delocalization of the unpaired electron in the chelate rings and from some molecular packing effects.

  6. Spectrophotometric investigation of interaction between iodine and pentadentate Schiff base ligands

    NASA Astrophysics Data System (ADS)

    Khouba, Z.; Benabdallah, T.; Maschke, U.

    The interaction between iodine as an electron acceptor (A), and three pentadentate Schiff bases, 1,3-bis(salicylideneamino)-2-propanol (SB1), 1,3-bis(2-hydroxy-1-naphthylideneamino)-2-propanol (SB2), and 1,3-bis[1-(pyridine-2-yl)methylideneamino]-2-propanol (SB3), as electron donor systems (D), was studied spectrophotometrically in methanol at 28 °C. Equilibrium constants KAD and molar extinction coefficients ?AD of the donor-acceptor complexes (AD) were determined using the modified Benesi-Hildebrand equation in conjunction with the non linear fit analysis. The method shows the formation of 1:1 type complexes as major species in solution. The free energy changes ?G° and the energy of the charge transfer band ECT were also calculated for all complexes. The iodine complex derived from SB2 seems to be more stable than those derived from SB3 and SB1. On the other hand, the ionization potential ID of each Schiff base was estimated from the corresponding complex band energy, using an empirical equation. An inverse relationship between ID and KAD values was found. Blue and red shift observed for the 445 nm band of iodine were also discussed on the basis of theoretical considerations.

  7. Spectrophotometric investigation of interaction between iodine and pentadentate Schiff base ligands.

    PubMed

    Khouba, Z; Benabdallah, T; Maschke, U

    2014-05-01

    The interaction between iodine as an electron acceptor (A), and three pentadentate Schiff bases, 1,3-bis(salicylideneamino)-2-propanol (SB1), 1,3-bis(2-hydroxy-1-naphthylideneamino)-2-propanol (SB2), and 1,3-bis[1-(pyridine-2-yl)methylideneamino]-2-propanol (SB3), as electron donor systems (D), was studied spectrophotometrically in methanol at 28 °C. Equilibrium constants K(AD) and molar extinction coefficients ?(AD) of the donor-acceptor complexes (AD) were determined using the modified Benesi-Hildebrand equation in conjunction with the non linear fit analysis. The method shows the formation of 1:1 type complexes as major species in solution. The free energy changes ?G° and the energy of the charge transfer band E(CT) were also calculated for all complexes. The iodine complex derived from SB2 seems to be more stable than those derived from SB3 and SB1. On the other hand, the ionization potential I(D) of each Schiff base was estimated from the corresponding complex band energy, using an empirical equation. An inverse relationship between I(D) and K(AD) values was found. Blue and red shift observed for the 445 nm band of iodine were also discussed on the basis of theoretical considerations. PMID:24530710

  8. XAFS study of metal chelates of phenylazo derivatives of Schiff bases

    NASA Astrophysics Data System (ADS)

    Burlov, Anatolii S.; Mashchenko, Sergey A.; Vlasenko, Valery G.; Zubavichus, Yan V.; Uraev, Ali I.; Lyssenko, Konstantin A.; Levchenkov, Sergei I.; Vasilchenko, Igor S.; Garnovskii, Dmitrii A.; Borodkin, Gennadii S.

    2014-03-01

    The Schiff base derived from o-tosylaminobenzaldehyde and p-aminoazobenzene and its metal chelates (Co2+, Ni2+, Cu2+, and Zn2+) have been synthesized and investigated (IR, 1H NMR, XANES, EXAFS spectroscopy, X-ray diffraction, magnetic measurements). It was found that the azomethine exists in the amino-imine tautomeric form both in solutions and solid state. XAFS investigations reveal that the complexes adopt either distorted tetrahedral or octahedral (due to additional coordination of oxygen atoms of the tosylamino group) ligand environment.

  9. Thermally induced oxidative decarboxylation of copper complexes of amino acids and formation of strecker aldehyde.

    PubMed

    Nashalian, Ossanna; Yaylayan, Varoujan A

    2014-08-20

    In the Maillard reaction, independent degradations of amino acids play an important role in the generation of amino-acid-specific products, such as Strecker aldehydes or their Schiff bases. Such oxidative decarboxylation reactions are expected to be enhanced in the presence of metals. Preliminary studies performed through heating of alanine and various metal salts (Cu, Fe, Zn, and Ca) under pyrolytic conditions indicated that copper(II) and iron(III) because of their high oxidation potentials were the only metals able to induce oxidative decarboxylation of amino acids and formation of Strecker aldehyde or its derivatives as detected by gas chromatography/mass spectrometry. Furthermore, studies performed with synthetic alanine and glycine copper complexes indicated that they constituted the critical intermediates undergoing free-radical oxidative degradation, followed by the loss of carbon dioxide and the generation of Strecker aldehydes, which were detected either as stable Schiff base adducts or incorporated in moieties, such as pyrazine or pyridine derivatives. PMID:25078730

  10. Mixed-ligand copper(II) phenolate complexes: Synthesis, spectral characterization, phosphate-hydrolysis, antioxidant, DNA interaction and cytotoxic studies

    NASA Astrophysics Data System (ADS)

    Gurumoorthy, Perumal; Mahendiran, Dharmasivam; Prabhu, Durai; Arulvasu, Chinnasamy; Rahiman, Aziz Kalilur

    2015-01-01

    A series of phenol-based mixed-ligand copper(II) complexes of the type [CuL1-4(diimine)] (1-8), where L1-4 = N1,N2-bis(5-substituted-2-hydroxybenzylidene)-1,2-ethylene/phenylenediimine and diimine = 2,2?-bipyridyl (bpy) or 1,10-phenanthroline (phen), have been isolated and fully characterized by analytical and spectral techniques. Electronic spectra of complexes suggest Cu(II) cation has a d9 electronic configuration, adopting distorted octahedral geometry with axial elongation, due to Jahn-Teller effect. Electrochemical studies of complexes evidenced one-electron irreversible reduction wave in the cathodic region. The observed rate constant (k) values for the hydrolysis of 4-nitrophenylphosphate (4-NPP) are in the range of 0.25-3.82 × 10-2 min-1. The obtained room temperature magnetic moment values (1.79-1.90 BM) lies within the range observed for octahedral copper(II) complexes. Antioxidant studies revealed that these complexes possess considerable radical scavenging potency against DPPH. The binding studies of complexes with calf thymus DNA (CT-DNA) revealed intercalation with minor-groove binding, and the complex 4 exhibits highest binding activity than the other complexes. The cleavage activity on supercoiled pBR322 DNA revealed the involvement of hydroxyl radical and singlet-oxygen as reactive oxygen species, and complexes encourage binding to minor-groove. Further, the cytotoxicity of complex 4 on human hepatocellular liver carcinoma HepG2 cell line implies the cell death through apoptosis.

  11. Transition metal complexes of quadridentate pyrazolo-based ligands with two thiolato and two imine donor atoms

    Microsoft Academic Search

    L. Hennig; R. Kirmse; O. Hammerich; S. Larsen; H. Frydendahl; H. Toftlund; J. Becher

    1995-01-01

    The copper(II), nickel(II) and cobalt(II) complexes of new S2N2 ligands on Schiff bases of 4-benzoyl-3-methyl-1-phenyl-2-pyrazoline-5-thione and various diamines were prepared and characterized. Using different diamines it is possible to control the geometry around the central metal atom. An X-ray structure determination of a Cu(II) S2N2 complex showed the (N?Cu?S, N?Cu?S) dihedral angle to be 52.11° and the following distances: Cu?S1

  12. The role of the retinylidene Schiff base counterion in rhodopsin in determining wavelength absorbance and Schiff base pKa.

    PubMed

    Sakmar, T P; Franke, R R; Khorana, H G

    1991-04-15

    Glu-113 serves as the retinylidene Schiff base counterion in bovine rhodopsin. Purified mutant rhodopsin pigments were prepared in which Glu-113 was replaced individually by Gln (E113Q), Asp (E113D), Asn (E113N), or Ala (E113A). E113Q, E113N, and E113A existed as pH-dependent equilibrium mixtures of unprotonated and protonated Schiff base (PSB) forms. The Schiff base pKa values determined by spectrophotometric titration were 6.00 (E113Q), 6.71 (E113N), and 5.70 (E113A). Thus, mutation of Glu-113 markedly reduced the Schiff base pKa. The addition of NaCl promoted the formation of a PSB in E113Q and E113A. An exogenously supplied solute anion replaced Glu-113 to compensate for the positive charge of the PSB in these mutants. The lambda max values of the PSB forms of the mutants in NaCl were 496 nm (E113Q), 506 nm (E113A), 510 nm (E113D), and 520 nm (E113N). To evaluate the effect of different types of solute anions on lambda max values, mutants were prepared in sodium salts of halides, perchlorate, and a series of carboxylic acids of various sizes and acidity. The lambda max values of E113Q and E113A depended on the solute anion present and ranged from 488 nm to 522 nm for E113Q and from 486 nm to 528 nm for E113A. The solute anion affected the lambda max values of E113N and E113D to lesser degrees. The reactivities of the mutants to hydroxylamine were also studied. Whereas rhodopsin was stable to hydroxylamine in the dark, E113N reacted slowly and E113Q reacted rapidly under these conditions, indicating structural differences in the Schiff base environments. The lambda max values and solute anion dependencies of the Glu-113 mutants indicate that interactions between Schiff base and its counterion play a significant role in determining the lambda max of rhodopsin. PMID:2014228

  13. Synthesis and degradation of Schiff bases containing heterocyclic pharmacophore.

    PubMed

    Lede?i, Ionu?; Alexa, Anda; Bercean, Vasile; Vlase, Gabriela; Vlase, Titus; ?uta, Lenu?a-Maria; Fulia?, Adriana

    2015-01-01

    This paper reports on the synthesis and characterization of two Schiff bases bearing 1,2,4-triazolic moieties, namely 4H-4-(2-hydroxy-benzylidene-amino)-5-benzyl-3-mercapto-1,2,4-triazole and 4H-4-(4-nitro-benzylidene-amino)-5-benzyl-3-mercapto-1,2,4-triazole using thin layer chromatography, melting interval, elemental analysis, spectroscopy and thermal stability studies. PMID:25590299

  14. Localization of the retinal protonated Schiff base counterion in rhodopsin.

    PubMed Central

    Han, M.; DeDecker, B. S.; Smith, S. O.

    1993-01-01

    Semiempirical molecular orbital calculations are combined with 13C NMR chemical shifts to localize the counterion in the retinal binding site of vertebrate rhodopsin. Charge densities along the polyene chain are calculated for an 11-cis-retinylidene protonated Schiff base (11-cis-RPSB) chromophore with 1) a chloride counterion at various distances from the Schiff base nitrogen, 2) one or two chloride counterions at different positions along the retinal chain from C10 to C15 and at the Schiff base nitrogen, and 3) a carboxylate counterion out of the retinal plane near C12. Increasing the distance of the negative counterion from the Schiff base results in an enhancement of alternating negative and positive partial charge on the even- and odd-numbered carbons, respectively, when compared to the 11-cis-RPSB chloride model compound. In contrast, the observed 13C NMR data of rhodopsin exhibit downfield chemical shifts from C8 to C13 relative to the 11-cis-RPSB.Cl corresponding to a net increase of partial positive or decrease of partial negative charge at these positions (Smith, S. O., I. Palings, M. E. Miley, J. Courtin, H. de Groot, J. Lugtenburg, R. A. Mathies, and R. G. Griffin. 1990. Biochemistry. 29:8158-8164). The anomalous changes in charge density reflected in the rhodopsin NMR chemical shifts can be qualitatively modeled by placing a single negative charge above C12. The calculated fit improves when a carboxylate counterion is used to model the retinal binding site. Inclusion of water in the model does not alter the fit to the NMR data, although it is consistent with observations based on other methods. These data constrain the location and the orientation of the Glu113 side chain, which is known to be the counterion in rhodopsin, and argue for a strong interaction centered at C12 of the retinylidene chain. PMID:8105993

  15. Synthesis and Degradation of Schiff Bases Containing Heterocyclic Pharmacophore

    PubMed Central

    Lede?i, Ionu?; Alexa, Anda; Bercean, Vasile; Vlase, Gabriela; Vlase, Titus; ?uta, Lenu?a-Maria; Fulia?, Adriana

    2015-01-01

    This paper reports on the synthesis and characterization of two Schiff bases bearing 1,2,4-triazolic moieties, namely 4H-4-(2-hydroxy-benzylidene-amino)-5-benzyl-3-mercapto-1,2,4-triazole and 4H-4-(4-nitro-benzylidene-amino)-5-benzyl-3-mercapto-1,2,4-triazole using thin layer chromatography, melting interval, elemental analysis, spectroscopy and thermal stability studies. PMID:25590299

  16. 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

  17. 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.

  18. Highly cytotoxic DNA-interacting copper(II) coordination compounds.

    PubMed

    Brissos, Rosa F; Torrents, Ester; dos Santos Mello, Francyelli Mariana; Carvalho Pires, Wanessa; Silveira-Lacerda, Elisângela de Paula; Caballero, Ana B; Caubet, Amparo; Massera, Chiara; Roubeau, Olivier; Teat, Simon J; Gamez, Patrick

    2014-10-01

    Four new Schiff-base ligands have been designed and prepared by condensation reaction between hydrazine derivatives (i.e. 2-hydrazinopyridine or 2-hydrazinoquinoline) and mono- or dialdehyde (3-tert-butyl-2-hydroxybenzaldehyde and 5-tert-butyl-2-hydroxyisophthalaldehyde, respectively). Six copper(II) coordination compounds of various nuclearities have been obtained from these ligands, which are formulated as [Cu(L1)Cl](CH3OH) (1), [Cu(L2)NO3] (2), [Cu2(L3)(ClO4)2(CH3O)(CH3OH)](CH3OH) (3), [Cu2(L4)(ClO4)(OH)(CH3OH)](ClO4) (4), [Cu8(L3)4(NO3)4(OH)5](NO3)3(CH3OH)5(H2O)8 (5) and [Cu3(HL2')4Cl6](CH3OH)6 (6), as revealed by single-crystal X-ray studies. Their DNA-interacting abilities have been investigated using different characterization techniques, which suggest that the metal complexes act as efficient DNA binders. Moreover, cytotoxicity assays with several cancer cell lines show that some of them are very active, as evidenced by the sub-micromolar IC50 values achieved in some cases. PMID:25096758

  19. Synthesis and spectral characterization of mono- and binuclear copper(II) complexes derived from 2-benzoylpyridine-N(4)-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 [Formula: see text] ground state. The thermal stabilities of some of the complexes were also determined. PMID:25546494

  20. Synthesis, immobilization and catalytic activity of a copper(II) complex with a chiral bis(oxazoline).

    PubMed

    Carneiro, Liliana; Silva, Ana R; Shuttleworth, Peter S; Budarin, Vitaly; Clark, James H

    2014-01-01

    A chiral bis(oxazoline) bearing CH2OH groups was synthesized from a commercial bis(oxazoline) and characterized by 1H- and 13C-NMR, high resolution ESI-mass spectrometry and FTIR. The corresponding copper(II) complex was immobilized onto the surface of a mesoporous carbonaceous material (Starbon® 700) in which the double bonds had been activated via conventional bromination. The materials were characterized by elemental analysis, ICP-OES, XPS, thermogravimetry and nitrogen adsorption at 77 K. The new copper(II) bis(oxazoline) was tested both in the homogeneous phase and once immobilized onto a carbonaceous support for the kinetic resolution of hydrobenzoin. Both were active, enantioselective and selective in the mono-benzoylation of hydrobenzoin, but better enantioselectivities were obtained in the homogeneous phase. The heterogeneous catalyst could be separated from the reaction media at the end of the reaction and reused in another catalytic cycle, but with loss of product yield and enantioselectivity. PMID:25116806

  1. Peculiar reactivity of a di-imine copper(II) complex regarding its binding to albumin protein.

    PubMed

    Silveira, Vivian C; Abbott, Mariana P; Cavicchioli, Maurício; Gonçalves, Marcos B; Petrilli, Helena M; de Rezende, Leandro; Amaral, Antonia T; Fonseca, David E P; Caramori, Giovanni F; Ferreira, Ana M da Costa

    2013-05-14

    A set of four di-imine copper(II) complexes containing pyridine, pyrazine and/or imidazole moieties, [Cu(apyhist)H2O](2+) 1 (apyhist = 2-(1H-imidazol-4-yl)-N-(1-(pyridin-2-yl)ethylidene)ethanamine), [Cu(apzhist)OH](+) 2 (apzhist = 2-(1H-imidazol-4-yl)-N-(1-(pyrazin-2-yl)ethylidene)ethanamine), [Cu(apyepy)OH](+) 3 (apyepy = 2-(pyridin-2-yl)-N-(1-(pyridin-2-yl)ethylidene)ethanamine), and [Cu(apzepy)H2O](2+) 4 (apzepy = N-(1-(pyrazin-2-yl)ethylidene)-2-(pyridin-2-yl)ethanamine), were investigated regarding their capability of interacting with serum albumin (human, HSA and bovine, BSA), by using spectroscopic techniques, CD, UV/Vis and EPR. Like other similar di-imine copper(II) complexes, most of them showed an expected preferential insertion of the metal ion at the primary N-terminal site of the protein, very selective for copper and characterized by a CD band at 560 nm. Further insertion of the copper ion at a secondary site is expected when using an excess of the metal. However, one of these studied complexes, [Cu(apyhist)H2O](2+) 1, exhibited anomalous behaviour interacting only at this secondary metal binding site of albumin, characterized by a CD band at 370 nm, and attributed to the coordination of copper at the Cys34 pocket. Analogous experiments with HSA previously treated with N-ethyl-maleimide (NEM), that oxidizes the protein Cys34 residue and obstructs the metal coordination, verified these results. Additional data obtained by EPR spectroscopy complemented those results. DFT calculations, considering some structural and electronic characteristics of such series of di-imine ligands and of the corresponding copper complexes, suggested molecular recognition of the apyhist ligand at the protein cavity as a feasible explanation for this unexpected and peculiar behaviour of complex 1. PMID:23462863

  2. IR and ESR study of copper(II) complexes with 15N-labelled lysine and ornithine

    NASA Astrophysics Data System (ADS)

    Cozar, O.; Bratu, I.; Szabó, L.; Cozar, I. B.; Chi?, V.; David, L.

    2011-05-01

    [ 15N]-labelled lysine and ornithine amino acids together with their copper(II) complexes are investigated by IR and ESR spectroscopies. The small isotopic shifts in the vibrations frequencies of the bonds involving the N atoms were evidenced by comparing IR spectra of [ 15N]-labelled and [ 14N]-forms of these amino acids. Different monomeric species and their local symmetries were established from ESR spectra of Cu(II)-[ 15N]-lysine (and ornithine) complexes adsorbed on NaY and HY zeolites. The in-plane ? bond has an ionic character ( ?2 ? 0.80) while the in-plane ? bond is more covalent ( ?2 ? 0.73) than that of the ? type for all these species.

  3. In Vivo Formation of a Schiff Base of Aminoguanidine with Pyridoxal Phosphate

    Microsoft Academic Search

    Tadao Taguchi; Michiharu Sugiura; Yoshiki Hamada; Ichitomo Miwa

    1998-01-01

    Aminoguanidine (AG) is considered to be a promising compound for the treatment of diabetic complications. We examined the in vitro and in vivo formation of Schiff bases of AG with pyridoxal 5?-phosphate (PLP) and pyridoxal (PL). AG reacted in vitro far more rapidly with PLP to form a Schiff base (PLP–AG) than with PL to form another Schiff base (PL–AG).

  4. Copper(II) complexes as catalyst for the aerobic oxidation of o-phenylenediamine to 2,3-diaminophenazine.

    PubMed

    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. PMID:25721653

  5. Antimicrobial salicylaldehyde Schiff bases: Synthesis, characterization and evaluation.

    PubMed

    Adeel-Sharif, Hafiz Muhammad; Ahmed, Dildar; Mir, Hira

    2015-03-01

    As the pathogens soon develop resistance to the existing antibiotics, the demand for new and more effective anti-microbial agents is a continuous phenomenon. In this paper we are reporting synthesis and spectral data of eight Schiff bases of salicylaldehyde with different amines, and evaluation of their anti-microbial activities against different bacterial strains. The bases were synthesized by reflux method, and their structures were determined based FT-IR, (1)H-NMR, (13)C-NMR and Mass spectrometric data. The Schiff bases synthesized included 2-{[(Z)-(2-hydroxyphenyl) methylidene] amino}benzoicacid (SB1), 4-{[(Z)-(2-hydroxyphenyl) methylidene] amino} benzoic acid (SB2),2-[(naphthalene-2-ylimino)methyl] phenol(SB3),2-2'-[benzene-1,4-diylbis(nitrilomethylylidene)]diphenol (SB4), 2-2'-[benzene-1,2-diylbis (nitrile-(E)-methylylidene)]diphenol (SB5), 2-[(2-phenylhydrazineylidene)methyl]phenol (SB6), 2-2'-[ethene-1,2-diylbis(iminomethanediyl)]diphenol (SB7) and 2-[(Z)-(phenylimino)methyl]phenol (SB8). The anti-microbial activities of synthesized Schiff bases were determined in terms of zones of inhibition and minimum inhibitory concentrations (MICs). All the bases showed moderate to good activities against all the tested microorganisms. The MICs of most compounds were 100-200?g/mL against different microorganisms. However, it was 50?g/mL for SB1 against P. aeruginosa (1), SB3 against P. aurantiaca, P. aeruginosa (1), E. coli (2), S. typhi (2) and C. freundii, SB4against E. coli (2), S. typhi (1) and S. maltophilia, SB5 against K. pneumoniae and S. typhi (2), SB6 against P. aeruginosa (3) and C. freundii, SB7 against E. cloacae and A. lipoferum, and SB8 against E. coli (2). Considerably active bases may prove to be potential candidates for future antibiotic drugs. PMID:25730802

  6. Potentiometric and spectroscopic study of the complexation of copper(II) ions by tripeptides containing aromatic side-chains

    NASA Astrophysics Data System (ADS)

    Ghalem, S.; Fan, B.-T.; Xiao, L.

    1998-01-01

    The complexation of copper(II) ions with L,L-Gly-Phe-Phe, L,L-Phe-Gly-Phe and L,L-Phe-Phe-Gly was studied by potentiometric and spectroscopic measurements. Only four complexes have been found for each copper(II)-tripeptide system, and no species with two ligand molecules was observed. The results show influences of aromatic side-chains. These influences are dependent upon the location of two aromatic rings in studied tripeptides. The stabilization or destabilization of a given complex is probably the result of several different effects, including steric hindrance, hydrophobic effect, electrodonor effect and ?-d interaction. The spectroscopic measurements, e.s.r and electronic absorption, are useful to determine the complex structures. La complexation du cuivre(II) par Gly-Phe-Phe-L,L, Phe-Gly-Phe-L,L et Phe-Phe-Gly-L,L a été étudiée par potentiométrie et par spectroscopies. Seulement quatre espèces ont été mises en évidence pour chaque système Cu(II)-tripeptide. Aucun complexe contenant deux molécules de ligand n'a été observé. Les résultats obtenus montrent des influences évidentes liées aux chaînes latérales aromatiques. Ces influences dépendent des positions des résidus phénylalanines. La stabilisation ou déstabilisation d'un complexe est probablement le résultat d'un ensemble de différents effets : effet stérique, effet hydrophobe, électrodonneur et l'interaction ?-d. Les spectroscopies RPE et visible ont été utilisées pour la détermination structurale des complexes.

  7. Specific Inhibition of the transcription factor Ci by a Cobalt(III)-Schiff base-DNA conjugate

    PubMed Central

    Hurtado, Ryan R.; Harney, Allison S.; Heffern, Marie C.; Holbrook, Robert J.; Holmgren, Robert A.; Meade, Thomas J.

    2012-01-01

    We describe the use of Co(III) Schiff base-DNA conjugates, a versatile class of research tools that target C2H2 transcription factors, to inhibit the Hedgehog (Hh) pathway. In developing mammalian embryos, Hh signaling is critical for the formation and development of many tissues and organs. Inappropriate activation of the Hedgehog (Hh) pathway has been implicated in a variety of cancers including medulloblastomas and basal cell carcinomas. It is well known that Hh regulates the activity of the Gli family of C2H2 zinc finger transcription factors in mammals. In Drosophila the function of the Gli proteins is performed by a single transcription factor with an identical DNA binding consensus sequence, Cubitus Interruptus (Ci). We have demonstrated previously that conjugation of a specific 17 base-pair oligonucleotide to a Co(III) Schiff base complex results in a targeted inhibitor of the Snail family C2H2 zinc finger transcription factors. Modification of the oligonucleotide sequence in the Co(III) Schiff base-DNA conjugate to that of Ci’s consensus sequence (Co(III)-Ci) generates an equally selective inhibitor of Ci. Co(III)-Ci irreversibly binds the Ci zinc finger domain and prevents it from binding DNA in vitro. In a Ci responsive tissue culture reporter gene assay, Co(III)-Ci reduces the transcriptional activity of Ci in a concentration dependent manner. In addition, injection of wild-type Drosophila embryos with Co(III)-Ci phenocopies a Ci loss of function phenotype, demonstrating effectiveness in vivo. This study provides evidence that Co(III) Schiff base-DNA conjugates are a versatile class of specific and potent tools for studying zinc finger domain proteins and have potential applications as customizable anti-cancer therapeutics. PMID:22214326

  8. Synthesis of a ruthenium(II) bipyridyl complex coordinated by a functionalized Schiff base ligand: Characterization, spectroscopic and isothermal titration calorimetry measurements of M 2+ binding and sensing (M 2+ = Ca 2+, Mg 2+)

    NASA Astrophysics Data System (ADS)

    Dixit, Namrata; Mishra, Lallan; Mustafi, Sourajit M.; Chary, Kandala V. R.; Houjou, Hirohiko

    2009-07-01

    Bis-[methylsalicylidine-4'benzoic acid]-ethylene (LH 2) complexed with cis-Ru(bpy) 2Cl 2·2H 2O provides a complex of composition [Ru(bpy) 2L]·2NH 4PF 6 ( 1), which has been characterized spectroscopically. Its binding behaviour towards Mg 2+ and Ca 2+ ions is monitored using 1H NMR titration, isothermal titration calorimetry (ITC) and luminescence microscopy. The luminescent ruthenium complex binds Ca 2+ in a more selective manner as compared to Mg 2+.

  9. Spectral properties of protonated Schiff base porphyrins and chlorins. INDO-CI calculations and resonance raman studies

    SciTech Connect

    Hanson, L.K.; Chang, C.K.; Ward, B.; Callahan, P.M.; Babcock, G.T.; Head, J.D.

    1984-07-11

    INDO-CI calculations successfully reproduce the striking changes in optical spectra that occur upon protonation of mono- and disubstituted porphyrin, chlorin, and bacteriochlorin Schiff base complexes. They ascribe the changes to Schiff base C=N ..pi..* orbitals which drop in energy upon protonation and mix with and perturb the ..pi..* orbitals of the macrocycle, a result consistent with resonance Raman data. The perturbation is predicted to affect not only transition energies and intensities but also dipole moment directions. The symmetry of the porphyrin and the substitution site of the chlorin are shown to play an important role, especially in governing whether the lowest energy transition will red shift or blue shift. Blue shifts are calculated for protonation of ketimine and enamine isomers of pyrochlorophyll a (PChl). Comparison with reported optical spectra suggests that PChl a Schiff base may undergo isomerization upon protonation. Resonance Raman data on CHO, CHNR, CHNHR/sup +/, and pyrrolidine adducts of chlorin demonstrate the isolation of the peripheral C=O and C=N groups from the macrocycle ..pi.. system intramolecular hydrogen bonding, and selective enhancement of v/sub C=N/ for those species with a split Soret band. V/sub C=N/ is observed with 488.0-nm excitation into the lower-energy Soret and absent for 406.7-nm excitation into the higher-energy Soret, a result predicted by the calculations. 44 references, 10 figures, 2 tables.

  10. Antioxidant, DNA binding and nuclease activities of heteroleptic copper(II) complexes derived from 2-((2-(piperazin-1-yl)ethylimino)methyl)-4-substituted phenols and diimines

    NASA Astrophysics Data System (ADS)

    Ravichandran, J.; Gurumoorthy, P.; Imran Musthafa, M. A.; Kalilur Rahiman, A.

    2014-12-01

    A series of heteroleptic copper(II) complexes of the type [CuL1-4(diimine)](ClO4)2 (1-8) [L1-4 = 2-((2-(piperazin-1-yl)ethylimino)methyl)-4-substituted phenols, and diimine = 2,2?-bipyridyl (bpy) or 1,10-phenanthroline (phen)], have been synthesized and characterized by spectroscopic methods. The IR spectra of complexes indicate the presence of uncoordinated perchlorate anions and the electronic spectra revealed the square pyramidal geometry with N4O coordination environment around copper(II) nuclei. Electrochemical studies of the mononuclear complexes evidenced one-electron irreversible reduction wave in the cathodic region. The EPR spectra of complexes with g|| (2.206-2.214) and A|| (154-172 × 10-4 cm-1) values support the square-based CuN3O coordination chromophore and the presence of unpaired electron localized in dx-y ground state. Antioxidant studies against DPPH revealed effective radical scavenging properties of the synthesized complexes. Binding studies suggest that the heteroleptic copper(II) complexes interact with calf thymus DNA (CT-DNA) through minor-groove and electrostatic interaction, and all the complexes display pronounced nuclease activity against supercoiled pBR322 DNA.

  11. Synthesis of N4 donor macrocyclic Schiff base ligands and their Ru (II), Pd (II), Pt (II) metal complexes for biological studies and catalytic oxidation of didanosine in pharmaceuticals

    NASA Astrophysics Data System (ADS)

    Ravi krishna, E.; Muralidhar Reddy, P.; Sarangapani, M.; Hanmanthu, G.; Geeta, B.; Shoba Rani, K.; Ravinder, V.

    2012-11-01

    A series of tetraaza (N4 donor) macrocyclic ligands (L1-L4) were derived from the condensation of o-phthalaldehyde (OPA) with some substituted aromatic amines/azide, and subsequently used to synthesize the metal complexes of Ru(II), Pd(II) and Pt(II). The structures of macrocyclic ligands and their metal complexes were characterized by elemental analyses, IR, 1H &13C NMR, mass and electronic spectroscopy, thermal, magnetic and conductance measurements. Both the ligands and their complexes were screened for their antibacterial activities against Gram positive and Gram negative bacteria by MIC method. Besides, these macrocyclic complexes were investigated as catalysts in the oxidation of pharmaceutical drug didanosine. The oxidized products were further treated with sulphanilic acid to develop the colored products to determine by spectrophotometrically. The current oxidation method is an environmentally friendly, simple to set-up, requires short reaction time, produces high yields and does not require co-oxidant.

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

    NASA Astrophysics Data System (ADS)

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

    2015-01-01

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

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

    PubMed

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

    2015-01-25

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

  14. Mixed ligand copper(II) complexes of phenanthroline/bipyridyl and curcumin diketimines as DNA intercalators and their electrochemical behavior under Nafion and clay modified electrodes.

    PubMed

    Annaraj, J; Srinivasan, S; Ponvel, K M; Athappan, Pr

    2005-03-01

    The mode of binding of copper(II) mixed ligand complexes of phen/bpy and Knoevenagel condensate of curcumin (4-salicylidene-1,7-bis(4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5-dione) and 4-X-anilines with herring sperm DNA has been investigated using spectral and electrochemical techniques in Tris-HCl buffer pH 7.1. On titration with DNA, usual hypochromism and unusual (large) red shift (30-35 nm) for some of these complexes were observed in their absorption spectra of intense intraligand (IL) pi-pi* transition around 420 nm. Variations in the absorbance due to their interaction with DNA on time scale were also investigated, under fixed concentrations of complex and DNA. On interaction with DNA, the quasi-reversible CuII/I redox couple slightly improves its reversibility with considerable decrease in current intensity. The intercalation of these copper complexes into the DNA base pairs was also investigated by gel retardation assay method. All the experimental results indicate that the phen mixed copper(II) complexes intercalate more effectively into the DNA base pairs than their bpy counterparts. Significant differences in the redox behavior of these copper(II) complexes under electrochemically modified GC electrodes with Nafion and K10 Montmorillonite clay have also been investigated and discussed. PMID:15708787

  15. 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.

  16. Pentacoordinated iron(II) complexes with 2,6-bis[(imino)ethyl]pyridine-Schiff base ligands as new catalyst systems mediated atom transfer radical polymerization of (meth)acrylate monomers

    Microsoft Academic Search

    Adnan Abu-Surrah; Khalid A. Ibrahim; Maher Y. Abdalla; Ayman A. Issa

    2011-01-01

    2,6-bis[1-(cis)-myrtanylimino)ethyl]pyridineiron(II) chloride (2) and 2,6-bis[(1-phenylimino)ethyl]pyridineiron(II) chloride (3) were investigated as novel complexes for iron-mediated atom transfer radical polymerization (ATRP) of methyl methacrylate\\u000a (MMA) and tert-butyl acrylate (tBA) using toluene as the solvent, and ethyl 2-bromoisobutyrate as the initiator. A catalyst\\/initiator molar ratio as low as\\u000a 0.1\\/1 was used in order to reduce catalyst contamination to the polymers. Both complexes produced

  17. A NEW CYCLOBUTANE SUBSTITUTED SCHIFF BASE LIGAND, SYNTHESIS OF ITS Cd(II), Co(II), Cu(II), Ni(II) AND Zn(II) COMPLEXES AND INVESTIGATION OF THEIR STRUCTURE

    Microsoft Academic Search

    Alaaddin Çukurovali; ?brahim Yilmaz

    2001-01-01

    A new, thiazole derivative ligand, 4-(1-phenyl-1-methylcyclobutane-3-yl)-2-(2-hydroxy-5-bromo benzylidenehydrazino) thiazole (LH), has been synthesized by the reaction of 2-hydroxy-5-bromobenzaldehyde, thiosemicarbazide and subsequently 1-phenyl-1-methyl-3-(2-chloro-1-oxoethyl) cyclobutane. Mononuclear complexes with a metal-ligand ratio of 1 : 2 have been prepared with Cd(II), Co(II), Cu(II), Ni(II) and Zn(II). The authenticity of the ligand and its complexes was established by elemental analyses, IR, C and H NMR

  18. Coordination properties of ionic liquid-mediated chromium(II) and copper(II) chlorides and their complexes with glucose.

    PubMed

    Pidko, Evgeny A; Degirmenci, Volkan; van Santen, Rutger A; Hensen, Emiel J M

    2010-11-01

    The structural and coordination properties of complexes formed upon the interaction of copper(II) and chromium(II) chlorides with dialkylimidazolium chloride (RMIm(+)Cl(-)) ionic liquids and glucose are studied by a combination of density functional theory (DFT) calculations and X-ray absorption spectroscopy (XAS). In the absence of the carbohydrate substrate, isolated mononuclear four-coordinated MeCl(4)(2-) species (Me = Cu, Cr) dominate in the ionic liquid solution. The organic part of the ionic liquid does not directly interact with the metal centers. The interactions between the RMIm(+) cations and the anionic metal chloride complexes are limited to hydrogen bonding with the basic Cl(-) ligands and the overall electrostatic stabilization of the anionic metal complexes. Exchange of Cl(-) ligands by a hydroxyl group of glucose is only favorable for CrCl(4)(2-). For Cu(2+) complexes, the formation of hydrogen bonded complexes between CuCl(4)(2-) and glucose is preferred. No preference for the coordination of metal chloride species to specific hydroxyl group of the carbohydrate is found. The formation of binuclear metal chloride complexes is also considered. The reactivity and selectivity patterns of the Lewis acid catalyzed reactions of glucose are discussed in the framework of the obtained results. PMID:20929259

  19. 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.

    PubMed

    Miao, Tiezheng; Zhang, Zhao; Feng, Weixu; Su, Peiyang; Feng, Heini; Lü, Xingqiang; Fan, Daidi; Wong, Wai-Kwok; Jones, Richard A; Su, Chengyong

    2014-11-11

    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. PMID:24866087

  20. A family of 13 tetranuclear zinc(II)-lanthanide(III) complexes of a [3+3] Schiff-base macrocycle derived from 1,4-diformyl-2,3-dihydroxybenzene.

    PubMed

    Feltham, Humphrey L C; Klöwer, Frederik; Cameron, Scott A; Larsen, David S; Lan, Yanhua; Tropiano, Manuel; Faulkner, Stephen; Powell, Annie K; Brooker, Sally

    2011-11-21

    A family of thirteen tetranuclear heterometallic zinc(II)-lanthanide(III) complexes of the hexa-imine macrocycle (L(Pr))(6-), with general formula Zn(II)(3)Ln(III)(L(Pr))(NO(3))(3)·xsolvents (Ln = La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm or Yb), were prepared in a one-pot synthesis using a 3:1:3:3 reaction of zinc(II) acetate, the appropriate lanthanide(III) nitrate, the dialdehyde 1,4-diformyl-2,3-dihydroxybenzene (H(2)L(1)) and 1,3-diaminopropane. A hexanuclear homometallic zinc(II) macrocyclic complex [Zn(6)(L(Pr))(OAc)(5)(OH)(H(2)O)]·3H(2)O was obtained using a 2:0:1:1 ratio of the same reagents. A control experiment using a 1:0:1:1 ratio failed to generate the lanthanide-free [Zn(3)(L(Pr))] macrocyclic complex. The reaction of H(2)L(1) and zinc(II) acetate in a 1:1 ratio yielded the pentanuclear homometallic complex of the dialdehyde H(2)L(1), [Zn(5)(L(1))(5)(H(2)O)(6)]·3H(2)O. An X-ray crystal structure determination revealed [Zn(3)(II)Pr(III)(L(Pr))(NO(3))(2)(DMF)(3)](NO(3))·0.9DMF has the large ten-coordinate lanthanide(III) ion bound in the central O(6) site with two bidentate nitrate anions completing the O(10) coordination sphere. The three square pyramidal zinc(II) ions are in the outer N(2)O(2) sites with a fifth donor from DMF. Measurement of the magnetic properties of [Zn(II)(3)Dy(III)(L(Pr))(NO(3))(3)(MeOH)(3)]·4H(2)O with a weak external dc field showed that it has a frequency-dependent out-of-phase component of ac susceptibility, indicative of slow relaxation of the magnetization (SMM behaviour). Likewise, the Er and Yb analogues are field-induced SMMs; the latter is only the second example of a Yb-based SMM. The neodymium, ytterbium and erbium complexes are luminescent in the solid phase, but only the ytterbium and neodymium complexes show strong lanthanide-centred luminescence in DMF solution. PMID:21935549

  1. Synthesis, characterization, structural analysis of metal(II) complexes of N'-[(E)-3-Bromo-5-Chloro-2-hydroxybenzidene]-4-hydroxybenzohydrazide-Multisubstituted Schiff base as a F(-) and Cu(2+) ions selective chemosensor.

    PubMed

    Sundar, A; Prabhu, M; Indra Gandhi, N; Marappan, M; Rajagopal, G

    2014-08-14

    New colorimetric chemosensor, N'-[(E)-3-Bromo-5-Chloro-2-hydroxybenzidene]-4-hydroxybenzohydrazide, containing OH and NH groups as binding sites have been synthesized and characterized by spectral UV, IR, NMR and ESR. The molecular structure of ligand is determined by X-ray crystallography and it has the monoclinic space group P21/c with cell parameters a=15.1058(6), b=14.3433(6), c=17.5800(8)Å and Z=8. The electronic spectral measurements show that Co(2+), Ni(2+) and Zn(2+) complexes have tetrahedral geometry, while Cu(2+) complex has square planar geometry. Magnetic measurements show that Cu(2+), Co(2+) and Ni(2+) complexes have paramagnetic behavior and Zn(2+) complex has diamagnetic behavior. Anion binding studies carried out using (1)H NMR and UV-visible spectrophotometric titrations revealed that these receptors exhibit selective recognition towards F(-) over other halide anions. The selectivity for F(-) among the halides is attributed mainly to the hydrogen-bond interaction of the receptor with F(-). Receptor (5 × 10(-5)M) shows color change from colorless to yellow in the presence of tetrabutylammonium fluoride (TBAF, 1.5 × 10(-3)M). Moreover, F(-)-induced color changes remain the same even in the presence of large excess of Cl(-), Br(-) and I(-). The binding constant is found to be higher towards F(-) ion and this may be due to presence of OH group, which offers extra binding site. Chromogenic receptor undergoes distinct color changes from colorless to green on gradual addition of Cu(2+) can be used as colorimetric probes for spectrophotometric and visual analysis of Cu(2+) in the presence of other transition metal ions such as Co(2+), Ni(2+) and Zn(2+). PMID:24759756

  2. Synthesis, characterization, structural analysis of metal(II) complexes of N?-[(E)-3-Bromo-5-Chloro-2-hydroxybenzidene]-4-hydroxybenzohydrazide-Multisubstituted Schiff base as a F- and Cu2+ ions selective chemosensor

    NASA Astrophysics Data System (ADS)

    Sundar, A.; Prabhu, M.; Indra Gandhi, N.; Marappan, M.; Rajagopal, G.

    2014-08-01

    New colorimetric chemosensor, N?-[(E)-3-Bromo-5-Chloro-2-hydroxybenzidene]-4-hydroxybenzohydrazide, containing OH and NH groups as binding sites have been synthesized and characterized by spectral UV, IR, NMR and ESR. The molecular structure of ligand is determined by X-ray crystallography and it has the monoclinic space group P21/c with cell parameters a = 15.1058(6), b = 14.3433(6), c = 17.5800(8) Å and Z = 8. The electronic spectral measurements show that Co2+, Ni2+ and Zn2+ complexes have tetrahedral geometry, while Cu2+ complex has square planar geometry. Magnetic measurements show that Cu2+, Co2+ and Ni2+ complexes have paramagnetic behavior and Zn2+ complex has diamagnetic behavior. Anion binding studies carried out using 1H NMR and UV-visible spectrophotometric titrations revealed that these receptors exhibit selective recognition towards F- over other halide anions. The selectivity for F- among the halides is attributed mainly to the hydrogen-bond interaction of the receptor with F-. Receptor (5 × 10-5 M) shows color change from colorless to yellow in the presence of tetrabutylammonium fluoride (TBAF, 1.5 × 10-3 M). Moreover, F--induced color changes remain the same even in the presence of large excess of Cl-, Br- and I-. The binding constant is found to be higher towards F- ion and this may be due to presence of OH group, which offers extra binding site. Chromogenic receptor undergoes distinct color changes from colorless to green on gradual addition of Cu2+ can be used as colorimetric probes for spectrophotometric and visual analysis of Cu2+ in the presence of other transition metal ions such as Co2+, Ni2+ and Zn2+.

  3. 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.

  4. Evidence for a bound water molecule next to the retinal Schiff base in bacteriorhodopsin and rhodopsin: a resonance Raman study of the Schiff base hydrogen/deuterium exchange.

    PubMed Central

    Deng, H.; Huang, L.; Callender, R.; Ebrey, T.

    1994-01-01

    The retinal chromophores of both rhodopsin and bacteriorhodopsin are bound to their apoproteins via a protonated Schiff base. We have employed continuous-flow resonance Raman experiments on both pigments to determine that the exchange of a deuteron on the Schiff base with a proton is very fast, with half-times of 6.9 +/- 0.9 and 1.3 +/- 0.3 ms for rhodopsin and bacteriorhodopsin, respectively. When these results are analyzed using standard hydrogen-deuteron exchange mechanisms, i.e., acid-, base-, or water-catalyzed schemes, it is found that none of these can explain the experimental results. Because the exchange rates are found to be independent of pH, the deuterium-hydrogen exchange can not be hydroxyl (or acid-)-catalyzed. Moreover, the deuterium-hydrogen exchange of the retinal Schiff base cannot be catalyzed by water acting as a base because in that case the estimated exchange rate is predicted to be orders of magnitude slower than that observed. The relatively slow calculated exchange rates are essentially due to the high pKa values of the Schiff base in both rhodopsin (pKa > 17) and bacteriorhodopsin (pKa approximately 13.5). We have also measured the deuterium-hydrogen exchange of a protonated Schiff base model compound in aqueous solution. Its exchange characteristics, in contrast to the Schiff bases of the pigments, is pH-dependent and consistent with the standard base-catalyzed schemes. Remarkably, the water-catalyzed exchange, which has a half-time of 16 +/- 2 ms and which dominates at pH 3.0 and below, is slower than the exchange rate of the Schiff base in rhodopsin and bacteriorhodopsin. Thus, there are two anomalous results, the inconsistency of the observed hydrogen exchange rates of retinal Schiff base in the two pigments with those predicted from the standard exchange schemes and the enhancement of the rate of hydrogen exchange in the two proteins over the model Schiff base in aqueous solution. We suggest that these results are explained by the presence of a structural water molecule (or molecules) at the retinal binding sites of the two pigments, quite close, probably-hydrogen bonded, to the Schiff base proton. In this case, the rate of exchange can be faster than that found for the model compound due to an "effective water concentration" near the Schiff base that is increased from that found in aqueous solution. PMID:8038384

  5. Copper(II) complexes with the N,N,O-tridentate ligand 6-amino-5-formyl-1,3-dimethyluracilato-(N6)-benzoylhydrazone: synthesis, spectral and XRD studies

    Microsoft Academic Search

    Francisco Hueso-Ureña; Miguel N. Moreno-Carretero; Antonio L. Peñas-Chamorro; José M. Amigó; Vicente Esteve; Tony Debaerdemaeker

    1999-01-01

    From reactions between different Cu(II) salts and the Schiff base 6-amino-5-formyl-1,3-dimethyluracil-benzoylhydrazone (H2BEZDO) in alcohol, six new copper complexes with simplified formulas [Cu(HBEZDO)(H2O)(MeOH)]NO3 (1), [CuCl(HBEZDO)(DMF)] (2), [CuBr(HBEZDO)]·2H2O (3), CuBr(HBEZDO) (4), Cu(ClO4)(HBEZDO)·H2O (5), and Cu(SO4)1\\/2(HBEZDO)·112H2O (6) were isolated. The structures of compounds 1, 2 and 3 have been established by means of XRD diffraction methods. In the three compounds, the Schiff base

  6. Enantioselective Friedel-Crafts alkylation reactions catalyzed by a chiral nonracemic C2-symmetric 2,2'-bipyridyl copper(II) complex.

    PubMed

    Lyle, Michael P A; Draper, Neil D; Wilson, Peter D

    2005-03-01

    Enantioselective Friedel-Crafts alkylation reactions of a series of substituted indoles with methyl trifluoropyruvate, catalyzed by a chiral nonracemic C(2)-symmetric 2,2'-bipyridyl copper(II) triflate complex, are described. The corresponding 3,3,3-trifluoro-2-hydroxy-2-indole-3-yl-propionic acid methyl esters were formed in good yield and in high enantiomeric excess (up to 90%). This is the first report of the use of a chiral nonracemic 2,2'-bipyridyl ligand in catalytic and enantioselective Friedel-Crafts alkylation reactions. The structural characterization of a copper(II) chloride complex of the chiral 2,2'-bipyridyl ligand by X-ray crystallography is also presented. [reaction: see text] PMID:15727470

  7. Controlling the pKa of the bacteriorhodopsin Schiff base by use of artificial retinal analogues.

    PubMed Central

    Sheves, M; Albeck, A; Friedman, N; Ottolenghi, M

    1986-01-01

    Artificial bacteriorhodopsin pigments based on synthetic retinal analogues carrying an electron-withdrawing CF3 substituent group were prepared. The effects of CF3 on the spectra, photocycles, and Schiff base pKa values of the pigments were analyzed. A reduction of 5 units in the pKa of the Schiff base is observed when the CF3 substituent is located at the C-13 polyene position, in the vicinity of the protonated Schiff base nitrogen. The results lead to the unambiguous characterization of the (direct) titration of the Schiff base in bacteriorhodopsin and to the conclusion that the deprotonation rate of the Schiff base during the photocycle (i.e., the generation of the M412 intermediate) is determined by a structural change in the protein. PMID:3458179

  8. Synthesis, spectroscopic properties and theoretical studies of bis-Schiff bases derived from polyamine and pyrazolones.

    PubMed

    Ren, Tiegang; Liu, Shuyun; Li, Guihui; Zhang, Jinglai; Guo, Jia; Li, Weijie; Yang, Lirong

    2012-11-01

    A series of novel bis-Schiff base were synthesized from 1-aryl-3-methyl-4-benzoyl-5-pyrazolones and diethylenetriamine (or triethylenetetramine) as the starting materials. All of these bis-Schiff bases were characterized by means of NMR, IR, and MS. The UV-vis absorption spectra and fluorescent spectra of these bis-Schiff bases were also measured. Moreover, the B3LYP/6-31G(d) method was used to optimize the ground state geometry of the bis-Schiff bases; and the UV-vis spectroscopic properties of the products were computed and compared with corresponding experimental data based on cc-pVDZ basis set of TD-B3LYP method. It has been found that all of these bis-Schiff bases show a remarkable absorption peak in a wavelength range of 270-340 nm; and their maximum emission peaks are around 348 nm. PMID:22750686

  9. Synthesis, spectroscopic properties and theoretical studies of bis-Schiff bases derived from polyamine and pyrazolones

    NASA Astrophysics Data System (ADS)

    Ren, Tiegang; Liu, Shuyun; Li, Guihui; Zhang, Jinglai; Guo, Jia; Li, Weijie; Yang, Lirong

    2012-11-01

    A series of novel bis-Schiff base were synthesized from 1-aryl-3-methyl-4-benzoyl-5-pyrazolones and diethylenetriamine (or triethylenetetramine) as the starting materials. All of these bis-Schiff bases were characterized by means of NMR, IR, and MS. The UV-vis absorption spectra and fluorescent spectra of these bis-Schiff bases were also measured. Moreover, the B3LYP/6-31G(d) method was used to optimize the ground state geometry of the bis-Schiff bases; and the UV-vis spectroscopic properties of the products were computed and compared with corresponding experimental data based on cc-pVDZ basis set of TD-B3LYP method. It has been found that all of these bis-Schiff bases show a remarkable absorption peak in a wavelength range of 270-340 nm; and their maximum emission peaks are around 348 nm.

  10. Dimeric versus polymeric coordination in copper(II) cationic complexes with bis(chelating) oxime and amide ligands.

    PubMed

    Buvailo, Andrii I; Gumienna-Kontecka, Elzbieta; Pavlova, Svetlana V; Fritsky, Igor O; Haukka, Matti

    2010-07-21

    A series of copper(ii) complexes with earlier reported ligands N,N'-bis(2-hydroxyiminopropionyl)-1,2-diaminoethane (H(2)pen) and 1,3-diaminopropane (H(2)pap) and novel open chain oxime and amide ligands, N,N'-bis(2-hydroxyiminopropionyl)-1,5-diaminopentane (H(2)papt), 1,6-diaminohexane (H(2)pah) and 1,7-diaminoheptane (H(2)pahp), were prepared and characterized by a variety of spectroscopic methods and X-ray structure analysis. Although a pH-potentiometric study revealed only monomeric species in solution, formation of both binuclear dimeric and 1D-polymeric topologies was found in solid state. In all complexes ligands provide bis-bidentate coordination to Cu(2+) ions via the nitrogen atoms of the oxime groups and the oxygen atoms of the amide groups to form CuN(2)O(2) planar fragments. Compound [Cu(Hpap)(ClO(4))(H(2)O)](x) was isolated in both dimeric (x = 2) and polymeric (x = n) state, representing an example of supramolecular isomerism. All the complexes are additionally stabilized by short intramolecular hydrogen bonds =N-O-H...O-N= between cis-arranged oximato-groups. Stabilization is more effective in the case of dimeric complexes compared to 1D-polymeric chain, which appears to be the reason of preferable dimerization versus polymerization in the studied set of compounds. The effect of polymethylene linker length on the conformation of the dimers is described. PMID:20520918

  11. Copper(II) complexes of a new N-picolylated bis benzimidazolyl diamide ligand: Synthesis, crystal structure and catechol oxidase studies

    Microsoft Academic Search

    Ruchi Bakshi; Miriam Rossi; Francesco Caruso; Pavan Mathur

    2011-01-01

    Copper(II) complexes of a new bis benzimidazole diamide ligand N-picolyl-N,N?-bis(2-methylbenzimidazolyl)hexanediamide [Pic-GBHA=L2] have been synthesized and characterized. One of the compound [Cu(L2)(NO3)2] has been structurally characterized. The copper atom is bound to two benzimidazolyl nitrogen atoms, two amide carbonyl oxygen atoms and a bidentate nitrate ion, resulting in a distorted octahedral geometry. EPR spectra obtained at low temperature indicate a tetragonal

  12. 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

  13. 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

  14. Perchlorate mixed-ligand copper(II) complexes of ?-diketone and ethylene diamine derivatives: Thermal, spectroscopic and biochemical studies

    NASA Astrophysics Data System (ADS)

    El-Ayaan, Usama; El-Metwally, Nashwa M.; Youssef, Magdy M.; El Bialy, Serry A. A.

    2007-12-01

    The present work carried out a study on perchlorate mixed-ligand copper(II) complexes which have been synthesized from ethylenediamine derivatives ( 3a- c) and ?-diketones. These complexes, namely [Cu(DA-Cl)(acac)H 2O]ClO 44, [Cu(DA-Cl)(bzac)H 2O]H 2O.ClO 45, [Cu(DA-OMe)(acac)H 2O]ClO 46, [Cu(DA-OMe)(bzac)H 2O]ClO 47, [Cu(DA-H)(acac)H 2O]2H 2O.ClO 48 and [Cu(DA-H)(bzac)H 2O]ClO 49 (where acac, acetylacetonate and bzac, benzoylacetonate) were characterized by elemental analysis, spectral (IR and UV-vis) and magnetic moment measurements. Thermal properties and decomposition kinetics of all complexes are investigated. The interpretation, mathematical analysis and evaluation of kinetic parameters ( E, A, ? H, ? S and ? G) of all thermal decomposition stages have been evaluated using Coats-Redfern equation. The biochemical studies showed that, the diamines 3a- c have powerful effects on degradation of DNA and protein. The antibacterial screening demonstrated that, the diamine (DA-Cl), 3b has the maximum and broad activities against Gram +ve and Gram -ve bacterial strains.

  15. Schiff bases as potential fungicides and nitrification inhibitors.

    PubMed

    Aggarwal, Nisha; Kumar, Rajesh; Dureja, Prem; Rawat, Diwan S

    2009-09-23

    A number of substituted Schiff bases were synthesized and characterized by (1)H NMR and mass spectrometry. These compounds were screened for antifungal activity in vitro against pathogenic fungi, namely, Sclerotium rolfsii and Rhizoctonia bataticola, and for their effect on nitrification inhibition under laboratory conditions. Maximum antifungal activity was exhibited by (2,4-dichlorobenzylidene)-(2,4,5-trichlorophenyl)-amine and (3-nitrobenzylidene)-(2,4,5-trichlorophenyl)-amine against both fungi (ED(50) with range from 3 to 24 microg/mL). Maximum nitrification inhibition (NI) was exhibited by (2,4-dichlorobenzylidene)-(2-fluorophenyl)-amine, (4-fluorophenyl)-(3-nitrobenzylidene)-amine, (2,6-dichlorobenzylidene)-(4-fluorophenyl)-amine, and (2,6-dichlorobenzylidene)-(3 fluorophenyl)-amine (NI in the range 91-96%). PMID:19702271

  16. Halochromism, ionochromism, solvatochromism and density functional study of a synthesized copper(II) complex containing hemilabile amide derivative ligand.

    PubMed

    Golchoubian, Hamid; Moayyedi, Golasa; Reisi, Neda

    2015-03-01

    This study investigates chromotropism of newly synthesized 3,3'-(ethane-1,2-diylbis(benzylazanediyl))dipropanamide copper(II) perchlorate complex. The compound was structurally characterized by physico-chemical and spectroscopic methods. X-ray crystallography of the complex showed that the copper atom achieved a distorted square pyramidal environment through coordination of two amine N atoms and two O atoms of the amide moieties. The pH effect on the visible absorption spectrum of the complex was studied which functions as pH-induced "off-on-off" switches through protonation and deprotonation of amide moieties along with the CuO to CuN bond rearrangement at room temperature. The complex was also observed to show solvatochromism and ionochromism. The distinct solution color changes mainly associated with hemilability of the amide groups. The solvatochromism of the complex was investigated with different solvent parameter models using stepwise multiple linear regression method. The results suggested that the basicity power of the solvent has a dominant contribution to the shift of the d-d absorption band of the complex. Density functional theory, DFT calculations were performed in order to study the electronic structure of the complex, the relative stabilities of the CuN/CuO isomers, and to understand the nature of the halochromism processes taking place. DFT computational results buttressed the experimental observations indicating that in the natural pH (5.8) the CuO isomer is more stable than its linkage isomer and conversely in alkaline aqueous solution. PMID:25434641

  17. 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.

  18. Copper(II) and gallium(III) complexes of trans-bis(2-hydroxybenzyl) cyclen derivatives: absence of a cross-bridge proves surprisingly more favorable.

    PubMed

    Esteves, Catarina V; Madureira, Joana; Lima, Luís M P; Mateus, Pedro; Bento, Isabel; Delgado, Rita

    2014-05-01

    Two cyclen (1,4,7,10-tetraazacyclododecane) derivatives bearing trans-bis(2-hydroxybenzyl) arms, the 1,7-(2-hydroxybenzyl)-1,4,7,10-tetraazacyclododecane (H2do2ph) and its cross-bridged counterpart (H2cb-do2ph), have been synthesized, aiming toward the possible use of their copper(II) and gallium(III) complexes in nuclear medicine. The protonation of both compounds was studied in aqueous solution as well as their complexes with Cu(2+) and Ga(3+) cations. The complexes of both ligands with Ca(2+) and Zn(2+) metal ions were also studied due to the abundance of these cations in biological media. In mild conditions the complexes of Ca(2+) and Ga(3+) with H2cb-do2ph did not form. The behavior of the two ligands and their complexes was compared by the values of the equilibrium constants, the data of varied spectroscopic techniques, the values of redox potentials of their copper(II) complexes, and the resistance of the complexes to acid dissociation. It was expected that, as found for related pairs of cyclen and cyclam (1,4,8,11-tetraazacyclotetradecane) derivatives, the cross-bridged macrocyclic derivative could be an excellent ligand for the complexation of copper(II). Additionally, the N-2-hydroxybenzyl groups were chosen due to their known ability to coordinate the gallium(III) cation. Due to the small size of the latter cation and its particular propensity to form hexacoordinate complexes, it was also expected that there would be a good ability of both ligands for the uptake of Ga(3+). Surprisingly, the results revealed that the cyclen derivative H2do2ph is the best ligand for the coordination of Cu(2+) and Ga(3+) cations, not only from their thermodynamic stability as expected but also from their kinetic inertness, when compared with its cross-bridged counterpart. PMID:24754354

  19. Trapping of muscle relaxant methocarbamol degradation product by complexation with copper(II) ion: spectroscopic and quantum chemical studies.

    PubMed

    Mansour, Ahmed M; Shehab, Ola R

    2014-07-15

    Structural properties of methocarbamol (Mcm) were extensively studied both experimentally and theoretically using FT IR, (1)H NMR, UV-Vis., geometry optimization, Mulliken charge, and molecular electrostatic potential. Stability arises from hyper-conjugative interactions, charge delocalization and H-bonding was analyzed using natural bond orbital (NBO) analysis. Mcm was decomposed in ethanol/water mixture at 80°C to guaifenesin [(RS)-3-(2-methoxyphenoxy)propane-1,2-diol] and carbamate ion [NH2COO(-)], where the degradation mechanism was explained by trapping the carbamate ion via the complexation with copper(II) ion. The structure of the isolated complex ([Cu(NH2COO)2(H2O)]?4H2O) was elucidated by spectral, thermal, and magnetic tools. Electronic spectra were discussed by TD-DFT and the descriptions of frontier molecular orbitals and the relocations of the electron density were determined. Calculated g-tensor values showed best agreement with experimental values from EPR when carried out using both the B3LYP and B3PW91 functional. PMID:24674917

  20. Anti-thyroid and antifungal activities, BSA interaction and acid phosphatase inhibition of methimazole copper(II) complexes.

    PubMed

    Urquiza, Nora M; Islas, María S; Ariza, Santiago T; Jori, Nadir; Martínez Medina, Juan J; Lavecchia, Martín J; López Tévez, Leonor L; Lezama, Luis; Rojo, Teófilo; Williams, Patricia A M; Ferrer, Evelina G

    2015-03-01

    It has been reported that various metal coordination compounds have improved some biological properties. A high activity of acid phosphatase (AcP) is associated to several diseases (osteoporosis, Alzheimer's, prostate cancer, among others) and makes it a target for the development of new potential inhibitors. Anti-thyroid agents have disadvantageous side effects and the scarcity of medicines in this area motivated many researchers to synthesize new ones. Several copper(II) complexes have shown antifungal activities. In this work we presented for a first time the inhibition of AcP and the anti-thyroid activity produced by methimazole-Cu(II) complexes. Cu-Met ([Cu(MeimzH)2(H2O)2](NO3)2·H2O) produces a weak inhibition action while Cu-Met-phen ([Cu(MeimzH)2(phen)(H2O)2]Cl2) shows a strong inhibition effect (IC50=300?M) being more effective than the reported behavior of vanadium complexes. Cu-Met-phen also presented a fairly good anti-thyroid activity with a formation constant value, Kc=1.02×10(10)M(-1) being 10(6) times more active than methimazole (Kc=4.16×10(4)M(-1)) in opposition to Cu-Met which presented activity (Kc=9.54×10(3)M(-1)) but in a lesser extent than that of the free ligand. None of the complexes show antifungal activity except Cu-phen (MIC=11.71?gmL(-1) on Candidaalbicans) which was tested for comparison. Besides, albumin interaction experiments denoted high affinity toward the complexes and the calculated binding constants indicate reversible binding to the protein. PMID:25641192

  1. Geometrical and optical benchmarking of copper(II) guanidine-quinoline complexes: insights from TD-DFT and many-body perturbation theory (part II).

    PubMed

    Hoffmann, Alexander; Rohrmüller, Martin; Jesser, Anton; dos Santos Vieira, Ines; Schmidt, Wolf Gero; Herres-Pawlis, Sonja

    2014-11-01

    Ground- and excited-state properties of copper(II) charge-transfer systems have been investigated starting from density-functional calculations with particular emphasis on the role of (i) the exchange and correlation functional, (ii) the basis set, (iii) solvent effects, and (iv) the treatment of dispersive interactions. Furthermore (v), the applicability of TD-DFT to excitations of copper(II) bis(chelate) charge-transfer systems is explored by performing many-body perturbation theory (GW?+?BSE), independent-particle approximation and ?SCF calculations for a small model system that contains simple guanidine and imine groups. These results show that DFT and TD-DFT in particular in combination with hybrid functionals are well suited for the description of the structural and optical properties, respectively, of copper(II) bis(chelate) complexes. Furthermore, it is found an accurate theoretical geometrical description requires the use of dispersion correction with Becke-Johnson damping and triple-zeta basis sets while solvent effects are small. The hybrid functionals B3LYP and TPSSh yielded best performance. The optical description is best with B3LYP, whereby heavily mixed molecular transitions of MLCT and LLCT character are obtained which can be more easily understood using natural transition orbitals. An natural bond orbital analysis sheds light on the donor properties of the different donor functions and the intraguanidine stabilization during coordination to copper(I) and (II). PMID:25255876

  2. Mono- and polynuclear copper(II) complexes of alloferons 1 with point mutations (H6A) and (H12A): stability structure and cytotoxicity.

    PubMed

    Kuczer, Mariola; B?aszak, Marta; Czarniewska, Elzbieta; Rosi?ski, Grzegorz; Kowalik-Jankowska, Teresa

    2013-05-20

    Mononuclear and polynuclear copper(II) complexes of the alloferons 1 (Allo1) with point mutations (H6A) H(1)GVSGA(6)GQH(9)GVH(12)G-COOH (Allo6A) and (H12A) H(1)GVSGH(6)GQH(9)GVA(12)G-COOH (Allo12A) have been studied by potentiometric, UV-visible, CD, EPR spectroscopic, and mass spectrometry (MS) methods. Complete complex speciation at different metal-to-ligand ratios ranging from 1:1 to 3:1 was obtained. At physiological pH 7.4 and a 1:1 metal-to-ligand molar ratio, the Allo6A and Allo12A peptides form CuL complexes with the 4N {NH2, N(Im)-H(1),2N(Im)} binding mode. The amine nitrogen donor and the imidazole nitrogen atoms (H(9)H(12) or H(6)H(9)) can be considered to be independent metal-binding sites in the species formed for the systems studied. As a consequence, di- and trinuclear complexes for the metal-to-ligand 2:1 and 3:1 molar ratios dominate in solution, respectively. The induction of apoptosis in vivo in Tenebrio molitor cells by the ligands and their copper(II) complexes at pH 7.4 was studied. The biological results show that copper(II) ions in vivo did not cause any apparent apoptotic features. The most active was the Cu(II)-Allo12A complex formed at pH 7.4 with a {NH2, N(Im)-H(1),N(Im)-H(6),N(Im)-H(9)} binding site. It exhibited 123% higher of caspase activity in hemocytes than the native peptide, Allo1. PMID:23656165

  3. A novel mixed valence copper(I) copper(II) bis(antipyryl-methyl)-piperazine complex: synthesis, molecular structure and spectroscopic characterization

    NASA Astrophysics Data System (ADS)

    Weinberger, P.; Costisor, O.; Tudose, R.; Baumgartner, O.; Linert, W.

    2000-02-01

    This paper describes a new case of the bis(antipyryl-methyl)-piperazine [BAMP] ligand being in the "boat"-conformation and acting as a tetradentate. But unlike in Co(BAMP)(NCS) 2, which is the only complex with BAMP acting as tetradentate known so far, the coordinated copper(II) is connected via a iodo-bridge to a Cu II 2-moiety. The synthesis, elemental analysis, spectroscopic (far- and mid-FTIR, UV-Vis) and structural characterization (X-ray diffraction) as well as magnetochemical and conductivity data of this novel mixed valence binuclear complex Cu ICu II(BAMP)I 3 are presented.

  4. 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

  5. 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.

    PubMed

    Mohamed, Gehad G; Zayed, Ehab M; Hindy, Ahmed M M

    2015-06-15

    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, (1)H 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. PMID:25767990

  6. Studies of intramolecular hydrogen bonds in di-Schiff bases of 2-hydroxy-5-methyl isophthaldehyde

    Microsoft Academic Search

    Zbigniew Rozwadowski; Teresa Dziembowska; Grzegorz Schroeder; Bogumil Brzezinski

    1998-01-01

    Di-Schiff bases obtained by the reaction of 2-hydroxy-5-methyl isophthaldehyde with 4-R-anilines (R = H, CH3 and OCH3) were synthesized and studied by ultraviolet-visible (UV-vis) spectrophotometry and 1H and 13C nuclear magnetic resonance (NMR) spectroscopy. The UV-vis spectra of di-Schiff bases 1–3 and their protonated and deprotonated analogues in acetonitrile are discussed. Isotope effects on the 13C NMR chemical shifts resulting

  7. Vibrational analysis of the all-trans retinal protonated Schiff base.

    PubMed Central

    Smith, S O; Myers, A B; Mathies, R A; Pardoen, J A; Winkel, C; van den Berg, E M; Lugtenburg, J

    1985-01-01

    We have obtained Raman spectra of a series of all-trans retinal protonated Schiff-base isotopic derivatives. 13C-substitutions were made at the 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, and 15 positions while deuteration was performed at position 15. Based on the isotopic shifts, the observed C--C stretching vibrations in the 1,100-1,400 cm-1 fingerprint region are assigned. Normal mode calculations using a modified Urey-Bradley force field have been refined to reproduce the observed frequencies and isotopic shifts. Comparison with fingerprint assignments of all-trans retinal and its unprotonated Schiff base shows that the major effect of Schiff-base formation is a shift of the C14--C15 stretch from 1,111 cm-1 in the aldehyde to approximately 1,163 cm-1 in the Shiff base. This shift is attributed to the increased C14--C15 bond order that results from the reduced electronegativity of the Schiff-base nitrogen compared with the aldehyde oxygen. Protonation of the Schiff base increases pi-electron delocalization, causing a 6 to 16 cm-1 frequency increase of the normal modes involving the C8--C9, C10--C11, C12--C13, and C14--C15 stretches. Comparison of the protonated Schiff base Raman spectrum with that of light-adapted bacteriorhodopsin (BR568) shows that incorporation of the all-trans protonated Schiff base into bacterio-opsin produces an additional approximately 10 cm-1 increase of each C--C stretching frequency as a result of protein-induced pi-electron delocalization. Importantly, the frequency ordering and spacing of the C--C stretches in BR568 is the same as that found in the protonated Schiff base. PMID:4016185

  8. 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.

  9. 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

  10. Studies on Six-Coordinate Octahedral Chromium(III) Chelates with Schiff Bases Derived from 4Acetyl3-methyl-1-(3?-chloro Phenyl)-2-pyrazolin-5-one

    Microsoft Academic Search

    P. M. Parikh; J. R. Shah

    1985-01-01

    In the present paper 4-acetyl-3-methyl-1-(3?-chlorophenyl)-2-pyrazolin-5-one and its Schiff bases with o-toludine, m-toludine, p-toludine, m-chloro-aniline, p-chloroaniline and ethanolamine were employed in the preparation of chromium(III) chelates. All ligands are found to have bidentate coordinating ability. The complexes are six-coordinate and nonelectrolytes. Spectral parameters have been calculated from the visible reflectance spectra.

  11. Novel oxygen chirality induced by asymmetric coordination of an ether oxygen atom to a metal center in a series of sugar-pendant dipicolylamine copperII complexes.

    PubMed

    Mikata, Yuji; Sugai, Yuko; Obata, Makoto; Harada, Masafumi; Yano, Shigenobu

    2006-02-20

    Six sugar-pendant 2,2'-dipicolylamine (DPA) ligands (L1-3 and L'1-3) have been prepared. OH-protected and unprotected D-glucose, D-mannose, and D-xylose were attached to a DPA moiety via an O-glycoside linkage. X-ray crystallography of the copper(II) complexes (1-5) with these ligands revealed that the anomeric oxygen atom is coordinated to the metal center in the solid state, generating a chiral center at the oxygen atom. The CD spectra of these copper complexes in methanol or aqueous solution exhibit Cotton effects in the d-d transition region, which indicates that the ether oxygen atoms remain coordinated to the metal center and the oxygen-atom chirality is preserved even in solution. For complexes 1 and 2, the inverted oxygen-atom chirality and chelate-ring conformation in the solid state are well correlated with the mirror-image CD spectra in methanol solution. The concomitant inversion of the asymmetric configuration around the copper center was also observed in a methanol solution of complex 3 and a pyridine solution of complex 2. The square-pyramidal/octahedral copper(II) centers also exhibited characteristic absorption and CD spectra. PMID:16471965

  12. 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 dx(2)-y(2) ground state. PMID:25602445

  13. 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.

  14. Spectral, biological screening of metal chelates of chalcone based Schiff bases of N-(3-aminopropyl) imidazole

    NASA Astrophysics Data System (ADS)

    Kalanithi, M.; Rajarajan, M.; Tharmaraj, P.; Sheela, C. D.

    2012-02-01

    Tridentate chelate complexes of Co(II), Ni(II), Cu(II) and Zn(II) have been synthesized from the chalcone based ligands 2-[1-(3-(1H-imidazol-1-yl)propylimino)-3-(phenylallyl)]phenol( HL1), 2-[1-(3-(1H-imidazol-1-yl)propylimino)-3-p-tolylallyl]phenol( HL2), 2-[1-(3-(1H-imidazol-1-yl)propylimino)-3-4-nitrophenylallyl]phenol( HL3). Microanalytical data, UV-vis spectrophotometric method, magnetic susceptibility measurements, IR, 1H NMR, Mass, and EPR techniques were used to characterize the structure of chelates. The electronic absorption spectra and magnetic susceptibility measurements suggest a distorted square planar geometry for the copper(II) ion. The other metal complexes show distorted tetrahedral geometry. The coordination of the ligands with metal(II) ions was further confirmed by solution fluorescence spectrum. The antimicrobial activity of the ligands and metal(II) complexes against the species Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, Bacillus subtilis, Candida albigans and Aspergillus niger has been carried out and compared. The electrochemical behavior of copper(II) complex is studied by cyclic voltammetry.

  15. Synthesis and spectroscopic studies of copper(II) complexes with 1-benzotriazol-1-yl-1-[(p-X-phenyl)hydrazono] propan-2-one

    Microsoft Academic Search

    Nadia M. Shuaib; Nouria A. Al-Awadi; Ali El-Dissouky; Abdel-Ghany Shoair

    2006-01-01

    A new series of copper(II) complexes resulted from the reaction of CuCl2·2H2O or Cu(ClO4)2·6H2O and 1-benzotriazol-1-yl-1-[(p-X-phenyl)hydrazono]-propan-2-one, X?=?H (HL), Cl (HL), Br (HL), OCH3 (HL) and CH3 (HL) have been synthesized and characterized by different spectral, magnetic measurements and elemental analysis. IR spectral data indicate that: (i) the free ligands exist in the hydrazo-ketone rather than azo-enol form in the solid

  16. X-ray photoelectron investigation of complex compounds of copper(II) with nitrogen-containing ligands

    SciTech Connect

    Nikol'skii, A.B.; Kudrev, A.G.; Kostikov, Yu.P.

    1986-06-01

    The binding energies of the Cu 2p/sub 3/2/ and N 1s/sub 1/2/ electrons in copper(II) chelates with the formulas Cu(en)/sub 2/X/sub 2/ (X = Cl, Br, ClO/sub 4/, SO/sub 4/, BPh/sub 4/; en denotes ethylenediamine), Cu(bipy)/sub 2/X/sub 2/ (X = Cl, Br, I, ClO/sub 4/, BPh/sub 4/; bipy denotes 2,2'-bipyridyl), Cu(phen)/sub 2/(ClO/sub 4/)/sub 2/ (phen denotes 1,10-phenanthroline), and Cu(bipy)SO/sub 4/ have been measured by x-ray photoelectron spectroscopy(XPS). From the obtained results the donor-acceptor abilities of the X acid ligand and of the bidentate nitrogen-containing ligands were estimated. A correlation between the energy of the Cu 2p/sub 3/2 electron and the position of the charge-transfer band in the UV absorption spectrum of the compounds of the ethylenediamine series has been established. A correlation between the energies of the Cu 2p/sub 3/2/ and N 1s/sub 1/2/ levels has been established for the series of compounds studied. The slope of the linear dependence of the energy of Cu 2p/sub 3/2/ on the energy of N 1s/sub 1/2/ is approx. 0.7. The possibility of the use of XPS for studying photochemical processes in polymer films with the participation of copper complexes has been demonstrated.

  17. Pyrene Schiff base: photophysics, aggregation induced emission, and antimicrobial properties.

    PubMed

    Kathiravan, Arunkumar; Sundaravel, Karuppasamy; Jaccob, Madhavan; Dhinagaran, Ganesan; Rameshkumar, Angappan; Arul Ananth, Devanesan; Sivasudha, Thilagar

    2014-11-26

    Pyrene containing Schiff base molecule, namely 4-[(pyren-1-ylmethylene)amino]phenol (KB-1), was successfully synthesized and well characterized by using (1)H, (13)C NMR, FT-IR, and EI-MS spectrometry. UV-visible absorption, steady-state fluorescence, time-resolved fluorescence, and transient absorption spectroscopic techniques have been employed to elucidate the photophysical processes of KB-1. It has been demonstrated that the absorption characteristics of KB-1 have been bathochromatically tuned to the visible region by extending the ?-conjugation. The extended ?-conjugation is evidently confirmed by DFT calculations and reveals that ???* transition is the major factor responsible for electronic absorption of KB-1. The photophysical property of KB-1 was carefully examined in different organic solvents at different concentrations and the results show that the fluorescence of this molecule is completely quenched due to photoinduced electron transfer. Intriguingly, the fluorescence intensity of KB-1 increases enormously by the gradual addition of water up to 90% with concomitant increase in fluorescence lifetime. This clearly signifies that this molecule has aggregation-induced emission (AIE) property. The mechanism of AIE of this molecule is suppression of photoinduced electron transfer (PET) due to hydrogen bonding interaction of imine donor with water. A direct evidence of PET process has been presented by using nanosecond transient absorption measurements. Further, KB-1 was successfully used for antimicrobial and bioimaging studies. The antimicrobial studies were carried out through disc diffusion method. KB-1 is used against both Gram-positive (Rhodococcus rhodochrous and Staphylococcus aureus) and Gram-negative (Escherichia coli and Pseudomonas aeruginosa) bacterial species and also fungal species (Candida albicans). The result shows KB-1 can act as an excellent antimicrobial agent and as a photolabeling agent. S. aureus, P. aeruginosa, and C. albicans were found to be the most susceptible microorganisms at 1 mM concentration among the bacteria used in the present investigation. PMID:25360825

  18. 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.

  19. Antitubercular and fluorescence studies of copper(II) complexes with quinolone family member, ciprofloxacin

    NASA Astrophysics Data System (ADS)

    Kharadi, G. J.

    2011-09-01

    Four new mixed-ligand complexes of Cu(II) with ciprofloxacin (Cip) and uninegative bidentate ligands have been synthesized and characterized. The structure of mixed-ligand complexes was investigated using spectroscopic method, physicochemical and elemental analyses. The fluorescence spectra of complexes show red shift, which may be due to the chelation by the ligands to the metal ion. It enhances ligand ability to accept electrons and decreases the electron transition energy. Antimycobacterial screening of ligand and its copper compound against Mycobacterium tuberculosis shows clear enhancement in the antitubercular activity upon copper complexation.

  20. 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

  1. Synthesis, Spectral and Antibacterial Studies of Copper(II) Tetraaza Macrocyclic Complexes

    PubMed Central

    Reddy, Puchakayala Muralidhar; Rohini, Rondla; Krishna, Edulla Ravi; Hu, Anren; Ravinder, Vadde

    2012-01-01

    A novel family of tetraaza macrocyclic Cu(II) complexes [CuLX2] (where L = N4 donor macrocyclic ligands) and (X = Cl?, NO3 ?) have been synthesized and characterized by elemental analysis, magnetic moments, IR, EPR, mass, electronic spectra and thermal studies. The magnetic moments and electronic spectral studies suggest square planar geometry for [Cu(DBACDT)]Cl2 and [Cu(DBACDT)](NO3)2 complexes and distorted octahedral geometry to the rest of the ten complexes. The biological activity of all these complexes against gram-positive and gram-negative bacteria was compared with the activity of existing commercial antibacterial compounds like Linezolid and Cefaclor. Six complexes out of twelve were found to be most potent against both gram-positive as well as gram-negative bacteria due to the presence of thio group in the coordinated ligands. PMID:22606024

  2. 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.

  3. The Schiff base bond configuration in bacteriorhodopsin and in model compounds.

    PubMed

    Livnah, N; Sheves, M

    1993-07-20

    The Schiff base linkage bond configuration of bacteriorhodopsin was studied using model compounds consisting of all-trans- and 13-cis-retinal-protonated Schiff bases bearing C = N anti and syn bond configurations. The C = N configuration was analyzed using a combination of Fourier transform infrared spectroscopy and isotopically labeled chromophores. It was found that, in the model compounds, the coupling between the C14--C15 stretching frequency and the N--H rock is weak in the all-trans-retinal-protonated Schiff base in both the anti and syn C = N configurations. However, this coupling is relatively strong in the 13-cis-retinal-protonated Schiff base in both the anti and syn C = N configurations. Thus, it is concluded that, in model compounds, the C14--C15 mode can serve as a marker for the C13 = C14 bond configuration but not for the C = N. A different situation may prevail in bacteriorhodopsin due to different conformations of the retinal chromophore in the protein binding site and in solution. This difference suggests that the C14--C15/NH coupling in retinal-protonated Schiff bases is affected by the retinal conformation. PMID:8343511

  4. 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

  5. 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.

  6. Copper(II) complexes of N-(2-{[(2E)-2-(2-Hydroxy-(5-substituted)-benzylidene)-hydrazino]carbonyl}phenyl)benzamide ligands and heterocyclic coligands

    NASA Astrophysics Data System (ADS)

    Chavan, S. S.; Sawant, V. A.; Jadhav, A. N.

    2014-01-01

    Some copper(II) complexes of the type [Cu(L1-3)(phen]?CH2Cl2 (1a-3a) and [Cu(L1-3) (bipy)]?CH2Cl2 (1b-3b) (where L1 = N-(2-{[(2E)-2-(2-Hydroxy-benzylidene)-hydrazino]carbonyl}phenyl)benzamide, L2 = N-(2-{[(2E)-2-(2-Hydroxy-(5-bromo)-benzylidene)-hydrazino]carbonyl}phenyl)benzamide, L3 = N-(2-{[(2E)-2-(2-Hydroxy-(5-methoxy)-benzylidene)-hydrazino]carbonyl}phenyl)benzamide; phen = 1,10-phenanthroline, bipy = 2,2?-bipyridine) have been prepared and characterized on the basis of elemental analyses, IR, UV-Vis and EPR spectral studies. IR spectra indicate that the ligand L1-3 exists in the keto form in the solid state, while at the time of complexation, it tautomerises into enol form. The single crystal X-ray diffraction study of the representative complex [Cu(L1) (phen)]?CH2Cl2 (1a) reveals the distorted square pyramidal geometry around copper(II). Crystal data of (1a): space group = P21/n, a = 11.5691(16) Å, b = 11.0885(15) Å, c = 24.890(4) Å, V = 3166.2(8) Å3, Z = 4. The electrochemical behavior of all the complexes indicate that the phen complexes appears at more positive potential as compared to those for bipy complexes, as a consequence of its stronger ? acidic character. All the complexes exhibit blue-green emission as a result of the fluorescence from the intra-ligand (? ? ??) emission excited state.

  7. Copper(II) complexes of N-(2-{[(2E)-2-(2-Hydroxy-(5-substituted)-benzylidene)-hydrazino]carbonyl}phenyl)benzamide ligands and heterocyclic coligands.

    PubMed

    Chavan, S S; Sawant, V A; Jadhav, A N

    2014-01-01

    Some copper(II) complexes of the type [Cu(L1-3)(phen]·CH2Cl2 (1a-3a) and [Cu(L1-3) (bipy)]·CH2Cl2 (1b-3b) (where L1=N-(2-{[(2E)-2-(2-Hydroxy-benzylidene)-hydrazino]carbonyl}phenyl)benzamide, L2=N-(2-{[(2E)-2-(2-Hydroxy-(5-bromo)-benzylidene)-hydrazino]carbonyl}phenyl)benzamide, L3=N-(2-{[(2E)-2-(2-Hydroxy-(5-methoxy)-benzylidene)-hydrazino]carbonyl}phenyl)benzamide; phen=1,10-phenanthroline, bipy=2,2'-bipyridine) have been prepared and characterized on the basis of elemental analyses, IR, UV-Vis and EPR spectral studies. IR spectra indicate that the ligand L1-3 exists in the keto form in the solid state, while at the time of complexation, it tautomerises into enol form. The single crystal X-ray diffraction study of the representative complex [Cu(L1) (phen)]·CH2Cl2 (1a) reveals the distorted square pyramidal geometry around copper(II). Crystal data of (1a): space group=P21/n, a=11.5691(16) Å, b=11.0885(15) Å, c=24.890(4) Å, V=3166.2(8) Å(3), Z=4. The electrochemical behavior of all the complexes indicate that the phen complexes appears at more positive potential as compared to those for bipy complexes, as a consequence of its stronger ? acidic character. All the complexes exhibit blue-green emission as a result of the fluorescence from the intra-ligand (???(*)) emission excited state. PMID:24001977

  8. H4octapa: Highly Stable Complexation of Lanthanide(III) Ions and Copper(II).

    PubMed

    Kálmán, Ferenc Krisztián; Végh, Andrea; Regueiro-Figueroa, Martín; Tóth, Éva; Platas-Iglesias, Carlos; Tircsó, Gyula

    2015-03-01

    The acyclic ligand octapa(4-) (H4octapa = 6,6'-((ethane-1,2-diylbis((carboxymethyl)azanediyl))bis(methylene))dipicolinic acid) forms stable complexes with the Ln(3+) ions in aqueous solution. The stability constants determined for the complexes with La(3+), Gd(3+), and Lu(3+) using relaxometric methods are log KLaL = 20.13(7), log KGdL = 20.23(4), and log KLuL = 20.49(5) (I = 0.15 M NaCl). High stability constants were also determined for the complexes formed with divalent metal ions such as Zn(2+) and Cu(2+) (log KZnL = 18.91(3) and log KCuL = 22.08(2)). UV-visible and NMR spectroscopic studies and density functional theory (DFT) calculations point to hexadentate binding of the ligand to Zn(2+) and Cu(2+), the donor atoms of the acetate groups of the ligand remaining uncoordinated. The complexes formed with the Ln(3+) ions are nine-coordinated thanks to the octadentate binding of the ligand and the presence of a coordinated water molecule. The stability constants of the complexes formed with the Ln(3+) ions do not change significantly across the lanthanide series. A DFT investigation shows that this is the result of a subtle balance between the increased binding energies across the 4f period, which contribute to an increasing complex stability, and the parallel increase of the absolute values of the hydration free energies of the Ln(3+) ions. In the case of the [Ln(octapa)(H2O)](-) complexes the interaction between the amine nitrogen atoms of the ligand and the Ln(3+) ions is weakened along the lanthanide series, and therefore the increased electrostatic interaction does not overcome the increasing hydration energies. A detailed kinetic study of the dissociation of the [Gd(octapa)(H2O)](-) complex in the presence of Cu(2+) shows that the metal-assisted pathway is the main responsible for complex dissociation at pH 7.4 and physiological [Cu(2+)] concentration (1 ?M). PMID:25692564

  9. Solid phase extraction of copper(II) by fixed bed procedure on cation exchange complexing resins.

    PubMed

    Pesavento, Maria; Sturini, Michela; D'Agostino, Girolamo; Biesuz, Raffaela

    2010-02-19

    The efficiency of the metal ion recovery by solid phase extraction (SPE) in complexing resins columns is predicted by a simple model based on two parameters reflecting the sorption equilibria and kinetics of the metal ion on the considered resin. The parameter related to the adsorption equilibria was evaluated by the Gibbs-Donnan model, and that related to the kinetics by assuming that the ion exchange is the adsorption rate determining step. The predicted parameters make it possible to evaluate the breakthrough volume of the considered metal ion, Cu(II), from different kinds of complexing resins, and at different conditions, such as acidity and ionic composition. PMID:20036367

  10. Copper(II) cyanido-bridged bimetallic nitroprusside-based complexes: Syntheses, X-ray structures, magnetic properties, {sup 57}Fe Moessbauer spectroscopy and thermal studies

    SciTech Connect

    Travnicek, Zdenek, E-mail: zdenek.travnicek@upol.c [Department of Inorganic Chemistry, Faculty of Science, Palacky University, Tr. 17. listopadu 12, CZ-771 46 Olomouc (Czech Republic); Herchel, Radovan; Mikulik, Jiri [Department of Inorganic Chemistry, Faculty of Science, Palacky University, Tr. 17. listopadu 12, CZ-771 46 Olomouc (Czech Republic); Zboril, Radek [Department of Physical Chemistry, Faculty of Science, Palacky University, Tr. 17. listopadu 12, CZ-771 46 Olomouc (Czech Republic)

    2010-05-15

    Three heterobimetallic cyanido-bridged copper(II) nitroprusside-based complexes of the compositions [Cu(tet)Fe(CN){sub 5}NO].H{sub 2}O (1), where tet=N,N'-bis(3-aminopropyl)ethylenediamine, [Cu(hto)Fe(CN){sub 5}NO].2H{sub 2}O (2), where hto=1,3,6,9,11,14-hexaazatricyclo[12.2.1.1{sup 6,9}]octadecane and [Cu(nme){sub 2}Fe(CN){sub 5}NO].H{sub 2}O (3), where nme=N-methylethylenediamine, were synthesized and characterized by el