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Sample records for copperii schiff-base complexes

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

    PubMed

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

    2014-12-10

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

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

    NASA Astrophysics Data System (ADS)

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

    2016-10-01

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

  3. Synthesis, structure and urease inhibition studies of Schiff base copper(II) complexes with planar four-coordinate copper(II) centers.

    PubMed

    Dong, Xiongwei; Guo, Taolian; Li, Yuguang; Cui, Yongming; Wang, Qiang

    2013-10-01

    Seven new Schiff base copper(II) complexes with planar four-coordinate copper(II) centers have been synthesized and structurally characterized. The solid state structures of complexes 1, 3, 4, 5, 6 and 7 present a square-planar coordination geometry at the metal centers while complex 2 shows a slightly distorted square-planar geometry. Density functional theory calculations have been performed to evaluate the electronic structure of copper(II) complex 7. Inhibition of jack bean urease by copper(II) complexes 1-7 have also been investigated, and potent inhibitory activities with IC50 range of 2.60-17.00μM have been observed for these mononuclear copper(II) complexes. A docking analysis using a DOCK program was conducted to explain the urease inhibitory activity of the copper(II) complexes and the structure-activity relationships were further discussed.

  4. Anti-cancer activity and mutagenic potential of novel copper(II) quinolinone Schiff base complexes in hepatocarcinoma cells.

    PubMed

    Duff, Brian; Thangella, Venkat Reddy; Creaven, Bernadette S; Walsh, Maureen; Egan, Denise A

    2012-08-15

    This study determined the cytotoxic, cyto-selective and mutagenic potential of novel quinolinone Schiff base ligands and their corresponding copper(II) complexes in human-derived hepatic carcinoma cells (Hep-G2) and non-malignant human-derived hepatic cells (Chang). Results indicated that complexation of quinolinone Schiff bases with copper served to significantly enhance cytotoxicity. Here, the complex of (7E)-7-(3-ethoxy-2-hydroxybenzylideamino)-4-methylquinolin-2(1H)-one (TV117-FM) exhibited the lowest IC(50) value (17.9 μM) following 96 h continuous exposure, which was comparable to cisplatin (15.0 μM). However, results revealed that TV117-FM lacked cytoselectivity over non-malignant cells. Additionally, the complex was minimally effluxed from cells via Pglycoprotein (P-gp) and was shown to be non-mutagenic in the Standard Ames test. Furthermore, BrdU incorporation assays showed that it was capable of inhibiting DNA synthesis in a concentrationand time-dependent manner. However, inhibition was not as a consequence of DNA intercalation, as illustrated in electrophoretic mobility shift assays. Interestingly, it was shown that the ligand was capable of inhibiting the action of topoisomerase II, but this was lost following complexation. This indicated that the mechanism of action of the novel copper(II) complex was different from that of the parent ligand and suggests that TV117-FM may have a therapeutic role to play in the treatment of hepatocellular carcinoma. Studies are currently underway to elucidate the exact in vitro mechanism of action of this novel, metal-based anti-cancer agent.

  5. Mixed-ligand copper(ii) Schiff base complexes: the role of the co-ligand in DNA binding, DNA cleavage, protein binding and cytotoxicity.

    PubMed

    Lian, Wen-Jing; Wang, Xin-Tian; Xie, Cheng-Zhi; Tian, He; Song, Xue-Qing; Pan, He-Ting; Qiao, Xin; Xu, Jing-Yuan

    2016-05-31

    Four novel mononuclear Schiff base copper(ii) complexes, namely, [Cu(L)(OAc)]·H2O (), [Cu(HL)(C2O4)(EtOH)]·EtOH (), [Cu(L)(Bza)] () and [Cu(L)(Sal)] () (HL = 1-(((2-((2-hydroxypropyl)amino)ethyl)imino)methyl)naphthalene-2-ol), Bza = benzoic acid, Sal = salicylic acid), were synthesized and characterized by X-ray crystallography, elemental analysis and infrared spectroscopy. Single-crystal diffraction analysis revealed that all the complexes were mononuclear molecules, in which the Schiff base ligand exhibited different coordination modes and conformations. The N-HO and O-HO inter- and intramolecular hydrogen bonding interactions linked these molecules into multidimensional networks. Their interactions with calf thymus DNA (CT-DNA) were investigated by UV-visible and fluorescence spectrometry, as well as by viscosity measurements. The magnitude of the Kapp values of the four complexes was 10(5), indicating a moderate intercalative binding mode between the complexes and DNA. Electrophoresis results showed that all these complexes induced double strand breaks of pUC19 plasmid DNA in the presence of H2O2 through an oxidative pathway. In addition, the fluorescence spectrum of human serum albumin (HSA) with the complexes suggested that the quenching mechanism of HSA by the complexes was a static process. Moreover, the antiproliferative activity of the four complexes against HeLa (human cervical carcinoma) and HepG-2 (human liver hepatocellular carcinoma) cells evaluated by colorimetric cell proliferation assay and clonogenic assay revealed that all four complexes had improved cytotoxicity against cancer cells. Inspiringly, complex , with salicylic acid as the auxiliary ligand, displayed a stronger anticancer activity, suggesting that a synergistic effect of the Schiff base complex and the nonsteroidal anti-inflammatory drug may be involved in the cell killing process. The biological features of mixed-ligand copper(ii) Schiff base complexes and how acetic auxiliary

  6. Synthesis, spectral characterization, DNA binding ability and antibacterial screening of copper(II) complexes of symmetrical NOON tetradentate Schiff bases bearing different bridges

    NASA Astrophysics Data System (ADS)

    Bahaffi, Saleh O.; Abdel Aziz, Ayman A.; El-Naggar, Maher M.

    2012-08-01

    A novel series of four copper(II) complexes were synthesized by thermal reaction of copper acetate salt with symmetrical tetradentate Schiff bases, N,N'bis(o-vanillin)4,5-dimethyl-l,2-phenylenediamine (H2L1), N,N'bis(salicylaldehyde)4,5-dimethyl-1,2-phenylenediamine (H2L2), N,N'bis(o-vanillin)4,5-dichloro-1,2-phenylenediamine (H2L3) and N,N'bis(salicylaldehyde)4,5-dichloro-1,2-phenylenediamine (H2L4), respectively. All the new synthesized complexes were characterized by using of microanalysis, FT-IR, UV-Vis, magnetic measurements, ESR, and conductance measurements, respectively. The data revealed that all the Schiff bases (H2L1-4) coordinate in their deprotonated forms and behave as tetradentate NOON coordinated ligands. Moreover, their copper(II) complexes have square planar geometry with general formula [CuL1-4]. The binding of the complexes with calf thymus DNA (CT-DNA) was investigated by UV-Vis spectrophotometry, fluorescence quenching and viscosity measurements. The results indicated that the complexes bind to CT-DNA through an intercalative mode. From the biological activity view, the copper(II) complexes and their parent ligands were screened for their in vitro antibacterial activity against the bacterial species Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli and Pseudomonas aeruginosai by well diffusion method. The complexes showed an increased activity in comparison to some standard drugs.

  7. Biologically active Schiff bases containing thiophene/furan ring and their copper(II) complexes: Synthesis, spectral, nonlinear optical and density functional studies

    NASA Astrophysics Data System (ADS)

    Gündüzalp, Ayla Balaban; Özsen, İffet; Alyar, Hamit; Alyar, Saliha; Özbek, Neslihan

    2016-09-01

    Schiff bases; 1,8-bis(thiophene-2-carboxaldimine)-p-menthane (L1) and 1,8-bis(furan-2-carboxaldimine)-p-menthane (L2) have been synthesized and characterized by elemental analysis, 1Hsbnd 13C NMR, UV-vis, FT-IR and LC-MS methods. 1H and 13C shielding tensors for L1 and L2 were calculated with GIAO/DFT/B3LYP/6-311++G(d,p) methods in CDCl3. The vibrational band assignments, nonlinear optical (NLO) activities, frontier molecular orbitals (FMOs) and absorption spectrum have been investigated by the same basis set. Schiff base-copper(II) complexes have been synthesized and structurally characterized with spectroscopic methods, magnetic and conductivity measurements. The spectroscopic data suggest that Schiff base ligands coordinate through azomethine-N and thiophene-S/furan-O donors (as SNNS and ONNO chelating systems) to give a tetragonal geometry around the copper(II) ions. Schiff bases and Cu(II) complexes have been screened for their biological activities on different species of pathogenic bacteria, those are, Gram positive bacteria: Bacillus subtitilus, Yersinia enterotica, Bacillus cereus, Listeria monocytogenes, Micrococcus luteus and Gram negative bacteria: Escherichia coli, Pseudomonas aeroginosa, Shigella dysenteriae, Salmonella typhi, Klebsiella pseudomonas by using microdilution technique (MIC values in mM). Biological activity results show that Cu(II) complexes have higher activities than parent ligands and metal chelation may affect significantly the antibacterial behavior of the organic ligands.

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

    NASA Astrophysics Data System (ADS)

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

    2011-06-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-03-01

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

  10. 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.

  11. DNA binding, cytotoxicity and apoptosis induction activity of a mixed-ligand copper(II) complex with taurine Schiff base and imidazole.

    PubMed

    Li, Mei; Kong, Lin Lin; Gou, Yi; Yang, Feng; Liang, Hong

    2014-07-15

    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.

  12. 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

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

    NASA Astrophysics Data System (ADS)

    Kumar, Ravinder; Mathur, Pavan

    2015-02-01

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

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

    PubMed

    Kumar, Ravinder; Mathur, Pavan

    2015-02-01

    Copper(II) complexes with a new N-Substituted benzimidazolyl schiff base ligand are used as catalyst for the oxidation of 1-phenyl propyne. The oxidation is carried out under mild conditions using stoichiometric amounts of oxidant and catalytic amounts of Cu(II) complex as catalyst. Effect of acid/base, oxidant, morphology and surfactant has been studied. Two major products of phenyl propyne oxidation are the α-diketonic product and a terminal aldehyde. Diketone is the major product under acidic conditions while aldehyde formation is highest under basic conditions. The maximum conversion is found with the NO3(-) bound complex. GC-MS is used to find the percentage yields of products. SEM and PXRD of the reused complexes as catalyst suggest that morphology affects the catalytic efficiency. PMID:25448979

  15. Interaction of copper(II) complex of compartmental Schiff base ligand N, N'-bis(3-hydroxysalicylidene)ethylenediamine with bovine serum albumin

    NASA Astrophysics Data System (ADS)

    Boghaei, Davar M.; Farvid, Shokouh S.; Gharagozlou, Mehrnaz

    2007-03-01

    Circular dichroism (CD) spectroscopy, cyclic voltammetry (CV) and differential pulse voltammetry (DPV) were used to investigate the interaction between copper(II) complex of compartmental Schiff base ligand (L), N, N'-bis(3-hydroxysalicylidene)ethylenediamine, and bovine serum albumin (BSA) in 0.1 mol dm -3 phosphate buffer solution adjusted to physiological pH 7.0 containing 20% (w/w) dimethylsulfoxide at room temperature. CD spectra show that the interaction of the copper(II) complex with BSA leads to changes in the α-helical content of BSA and therefore changes in secondary structure of the protein with the slight red shift (2 nm) in CD spectra. From the voltammetric data, i.e. changes in limiting current with addition of BSA, the binding constant ( K) of the interaction of copper(II) complex with BSA was found to be 1.96 × 10 4 dm 3 mol -1. From the shifts in potential with the addition of BSA, the equilibrium constant ratio ( K2/ K1) for the binding of the oxidized Cu IIL ( K1) and reduced Cu IL ( K2) species to BSA was found to be 3.77, which shows that the reduced form Cu IL is bound more strongly to BSA than the oxidized form Cu IIL.

  16. The interaction of taurine-salicylaldehyde Schiff base copper(II) complex with DNA and the determination of DNA using the complex as a fluorescence probe

    NASA Astrophysics Data System (ADS)

    Zhang, Xiaoyan; Wang, Yong; Zhang, Qianru; Yang, Zhousheng

    2010-09-01

    The interaction of taurine-salicylaldehyde Schiff base copper(II) (Cu(TSSB) 22+) complex with DNA was explored by using UV-vis, fluorescence spectrophotometry, and voltammetry. In pH 7.4 Tris-HCl buffer solution, the binding constant of the Cu(TSSB) 22+ complex interaction with DNA was 3.49 × 10 4 L mol -1. Moreover, due to the fluorescence enhancing of Cu(TSSB) 22+ complex in the presence of DNA, a method for determination of DNA with Cu(TSSB) 22+ complex as a fluorescence probe was developed. The fluorescence spectra indicated that the maximum excitation and emission wavelength were 389 nm and 512 nm, respectively. Under optimal conditions, the calibration graphs are linear over the range of 0.03-9.03 μg mL -1 for calf thymus DNA (CT-DNA), 0.10-36 μg mL -1 for yeast DNA and 0.01-10.01 μg mL -1 for salmon DNA (SM-DNA), respectively. The corresponding detection limits are 7 ng mL -1 for CT-DNA, 3 ng mL -1 for yeast DNA and 3 ng mL -1 for SM-DNA. Using this method, DNA in synthetic samples was determined with satisfactory results.

  17. Structural studies of copper(II) complexes with 2-(2-aminoethyl)pyridine derived Schiff bases and application as precursors of thin organic-inorganic layers.

    PubMed

    Barwiolek, Magdalena; Szlyk, Edward; Berg, Andrzej; Wojtczak, Andrzej; Muziol, Tadeusz; Jezierska, Julia

    2014-07-14

    Cu(ii) complexes with Schiff bases derived from 2-pyridin-2-ylethanamine were obtained and characterized by UV-Vis, fluorescence, and IR spectra. The X-ray crystal structures determined for [Cu(ii)(epy(di-t-Buba))Cl] × 0.042H2O and [Cu(ii)(epy(di-t-Buba))O2CCH3] revealed tetrahedral distortion of the Cu(ii) coordination sphere in the solid phase. For both molecules the Cu(ii) ions were found in tetragonal environments, as was confirmed by the values of EPR g-matrix diagonal components. The thermal properties of the complexes and the gas phase composition were studied by TG/IR techniques. Thin layers of the studied copper(ii) complexes were deposited on Si(111) by a spin coating method and characterized by scanning electron microscopy (SEM/EDS), atomic force microscopy (AFM) and fluorescence spectra. For copper(ii) layers the most intensive fluorescence band from intra-ligand transition was observed between 498 and 588 nm. The layers' fluorescence intensity was related to the rotation speed and deposition time.

  18. 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

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

    PubMed

    Nagaraj, Karuppiah; Sakthinathan, Subramanian; Arunachalam, Sankaralingam

    2014-03-01

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

  20. Synthesis, DNA binding, cellular DNA lesion and cytotoxicity of a series of new benzimidazole-based Schiff base copper(II) complexes.

    PubMed

    Paul, Anup; Anbu, Sellamuthu; Sharma, Gunjan; Kuznetsov, Maxim L; Koch, Biplob; Guedes da Silva, M Fátima C; Pombeiro, Armando J L

    2015-12-14

    A series of new benzimidazole containing compounds 2-((1-R-1-H-benzimidazol-2-yl)phenyl-imino)naphthol HL(1-3) (R = methyl, ethyl or propyl, respectively) have been synthesized by Schiff base condensation of 2-(1-R-1-H-benzo[d]imidazol-2-yl)aniline and 2-hydroxy-1-naphthaldehyde. The reactions of HL(1-3) with Cu(NO3)2·2.5H2O led to the corresponding copper(II) complexes [Cu(L)(NO3)] 1-3. All the compounds were characterized by conventional analytical techniques and, for 1 and 3, also by single-crystal X-ray analysis. The interactions of complexes 1-3 with calf thymus DNA were studied by absorption and fluorescence spectroscopic techniques and the calculated binding constants (K(b)) are in the range of 3.5 × 10(5) M(-1)-3.2 × 10(5) M(-1). Complexes 1-3 effectively bind DNA through an intercalative mode, as proved by molecular docking studies. The binding affinity of the complexes decreases with the size increase of the N-alkyl substituent, in the order of 1 > 2 > 3, which is also in accord with the calculated LUMO(complex) energies. They show substantial in vitro cytotoxic effect against human lung (A-549), breast (MDA-MB-231) and cervical (HeLa) cancer cell lines. Complex 1 exhibits a significant inhibitory effect on the proliferation of the A-549 cancer cells. The antiproliferative efficacy of 1 has also been analysed by a DNA fragmentation assay, fluorescence activated cell sorting (FACS) and nuclear morphology using a fluorescence microscope. The possible mode for the apoptosis pathway of 1 has also been evaluated by a reactive oxygen species (ROS) generation study.

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

    NASA Astrophysics Data System (ADS)

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

    2011-12-01

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

  2. 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.

  3. 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.

  4. Asymmetric Schiff bases derived from diaminomaleonitrile and their metal complexes

    NASA Astrophysics Data System (ADS)

    Yang, Jianjie; Shi, Rufei; Zhou, Pei; Qiu, Qiming; Li, Hui

    2016-02-01

    Asymmetric Schiff bases, due to its asymmetric structure, can be used as asymmetric catalyst, antibacterial, and mimic molecules during simulate biological processes, etc. In recent years, research on synthesis and properties of asymmetric Schiff bases have become an increase interest of chemists. This review summarizes asymmetric Schiff bases derived from diaminomaleonitrile (DAMN) and DAMN-based asymmetric Schiff bases metal complexes. Applications of DAMN-based asymmetric Schiff bases are also discussed in this review.

  5. 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.

  6. 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

  7. Enantioselective catalysis using lanthanide Schiff base complexes

    SciTech Connect

    Watkin, J.G.

    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.

  8. Synthesis, crystal structure and magnetic properties of three unprecedented tri-nuclear and one very rare tetra-nuclear copper(II) Schiff-base complexes supported by mixed azido/phenoxo/nitrato or acetato bridges.

    PubMed

    Biswas, Chaitali; Drew, Michael G B; Ruiz, Eliseo; Estrader, Marta; Diaz, Carmen; Ghosh, Ashutosh

    2010-08-28

    Three novel mixed bridged trinuclear and one tetranuclear copper(II) complexes of tridentate NNO donor Schiff base ligands [Cu(3)(L(1))(2)(mu(1,1)-N(3))(2)(CH(3)OH)(2)(BF(4))(2)] (1), [Cu(3)(L(1))(2)(mu(1,1)-N(3))(2)(mu-NO(3)-1kappaO:2kappaO')(2)] (2), [Cu(3)(L(2))(2)(mu(1,1)-N(3))(2)(mu-NO(3)-1kappaO:2kappaO')(2)] (3) and [Cu(4)(L(3))(2)(mu(1,1)-N(3))(4)(mu-CH(3)COO-1kappaO:2kappaO')(2)] (4) have been synthesized by reaction of the respective tridentate ligands (L(1) = 2-[1-(2-dimethylamino-ethylimino)-ethyl]-phenol, L(2) = 2-[1-(2-diethylamino-ethylimino)-ethyl]-phenol, L(3) = 2-[1-(2-dimethylamino-ethylimino)-methyl]-phenol) with the corresponding copper(ii) salts in the presence of NaN(3). The complexes are characterized by single-crystal X-ray diffraction analyses and variable-temperature magnetic measurements. Complex 1 is composed of two terminal [Cu(L(1))(mu(1,1)-N(3))] units connected by a central [Cu(BF(4))(2)] unit through nitrogen atoms of end-on azido ligands and a phenoxo oxygen atom of the tridentate ligand. The structures of 2 and 3 are very similar; the only difference is that the central unit is [Cu(NO(3))(2)] and the nitrate group forms an additional mu-NO(3)-1kappaO:2kappaO' bridge between the terminal and central copper atoms. In complex 4, the central unit is a di-mu(1,1)-N(3) bridged dicopper entity, [Cu(2)(mu(1,1)-N(3))(2)(CH(3)COO)(2)] that connects two terminal [Cu(L(3))(mu(1,1)-N(3))] units through end-on azido, phenoxo oxygen and mu-CH(3)COO-1kappaO:2kappaO' triple bridges to result in a tetranuclear unit. Analyses of variable-temperature magnetic susceptibility data indicates that there is a global weak antiferromagnetic interaction between the copper(II) ions in complexes 1-3, with the exchange parameter J of -9.86, -11.6 and -19.98 cm(-1) for 1-3, respectively. In complex 4 theoretical calculations show the presence of an antiferromagnetic coupling in the triple bridging ligands (acetato, phenoxo and azido) while the interaction

  9. Synthesis, characterization, crystal structure determination and computational study of a new Cu(II) complex of bis [2-{(E)-[2-chloroethyl)imino]methyl}phenolato)] copper(II) Schiff base complex

    NASA Astrophysics Data System (ADS)

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

    2016-07-01

    The copper (II) Schiff base complex of [CuL2] (1), HL = 2-{(E)-[2-chloroethyl) imino]methyl}phenol, has been synthesized and characterized by elemental (CHN) analysis, UV-Vis and FT-IR spectroscopy. The molecular structure of 1 was determined by single crystal X-ray diffraction technique. The conformational analysis and molecular structures of CuL2 were investigated by means of density functional theory (DFT) calculations at B3LYP/6-311G* level. An excellent agreement was observed between theoretical and experimental results. The Schiff base ligand of HL acts as a chelating ligand and coordinates via one nitrogen atom and one oxygen atom to the metal center. The copper (II) center is coordinated by two nitrogen atoms and two oxygen atoms from two Schiff base ligands in an approximately square planar trans-[MN2O2] coordination geometry. Thermogravimetric analysis of CuL2 showed that it was decomposed in five stages. In addition, the CuL2 complex thermally decomposed in air at 660 °C and the XRD pattern of the obtained solid showed the formation of CuO nanoparticles with an average size of 34 nm.

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

    NASA Astrophysics Data System (ADS)

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

    2016-12-01

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

  11. Synthesis and crystal structure of the dinuclear copper(II) Schiff base complex μ-hydroxido-μ-chlorido-bis{[bis(trans-2-nitrocinnamaldehyde)ethylenediamine]chloridocopper(II)} dichloromethane sesquisolvate.

    PubMed

    Barati, Kazem; Clegg, William; Habibi, Mohammad Hossein; Harrington, Ross W; Lalegani, Arash; Montazerozohori, Morteza

    2016-03-01

    Transition metal complexes of Schiff base ligands have been shown to have particular application in catalysis and magnetism. The chemistry of copper complexes is of interest owing to their importance in biological and industrial processes. The reaction of copper(I) chloride with the bidentate Schiff base N,N'-bis(trans-2-nitrocinnamaldehyde)ethylenediamine {Nca2en, systematic name: (1E,1'E,2E,2'E)-N,N'-(ethane-1,2-diyl)bis[3-(2-nitrophenyl)prop-2-en-1-imine]} in a 1:1 molar ratio in dichloromethane without exclusion of air or moisture resulted in the formation of the title complex μ-chlorido-μ-hydroxido-bis(chlorido{(1E,1'E,2E,2'E)-N,N'-(ethane-1,2-diyl)bis[3-(2-nitrophenyl)prop-2-en-1-imine]-κ(2)N,N'}copper(II)) dichloromethane sesquisolvate, [Cu2Cl3(OH)(C20H18N4O4)2]·1.5CH2Cl2. The dinuclear complex has a folded four-membered ring in an unsymmetrical Cu2OCl3 core in which the approximate trigonal bipyramidal coordination displays different angular distortions in the equatorial planes of the two Cu(II) atoms; the chloride bridge is asymmetric, but the hydroxide bridge is symmetric. The chelate rings of the two Nca2en ligands have different conformations, leading to a more marked bowing of one of the ligands compared with the other. This is the first reported dinuclear complex, and the first five-coordinate complex, of the Nca2en Schiff base ligand. Molecules of the dimer are associated in pairs by ring-stacking interactions supported by C-H...Cl interactions with solvent molecules; a further ring-stacking interaction exists between the two Schiff base ligands of each molecule.

  12. Synthesis and crystal structure of the dinuclear copper(II) Schiff base complex μ-hydroxido-μ-chlorido-bis{[bis(trans-2-nitrocinnamaldehyde)ethylenediamine]chloridocopper(II)} dichloromethane sesquisolvate.

    PubMed

    Barati, Kazem; Clegg, William; Habibi, Mohammad Hossein; Harrington, Ross W; Lalegani, Arash; Montazerozohori, Morteza

    2016-03-01

    Transition metal complexes of Schiff base ligands have been shown to have particular application in catalysis and magnetism. The chemistry of copper complexes is of interest owing to their importance in biological and industrial processes. The reaction of copper(I) chloride with the bidentate Schiff base N,N'-bis(trans-2-nitrocinnamaldehyde)ethylenediamine {Nca2en, systematic name: (1E,1'E,2E,2'E)-N,N'-(ethane-1,2-diyl)bis[3-(2-nitrophenyl)prop-2-en-1-imine]} in a 1:1 molar ratio in dichloromethane without exclusion of air or moisture resulted in the formation of the title complex μ-chlorido-μ-hydroxido-bis(chlorido{(1E,1'E,2E,2'E)-N,N'-(ethane-1,2-diyl)bis[3-(2-nitrophenyl)prop-2-en-1-imine]-κ(2)N,N'}copper(II)) dichloromethane sesquisolvate, [Cu2Cl3(OH)(C20H18N4O4)2]·1.5CH2Cl2. The dinuclear complex has a folded four-membered ring in an unsymmetrical Cu2OCl3 core in which the approximate trigonal bipyramidal coordination displays different angular distortions in the equatorial planes of the two Cu(II) atoms; the chloride bridge is asymmetric, but the hydroxide bridge is symmetric. The chelate rings of the two Nca2en ligands have different conformations, leading to a more marked bowing of one of the ligands compared with the other. This is the first reported dinuclear complex, and the first five-coordinate complex, of the Nca2en Schiff base ligand. Molecules of the dimer are associated in pairs by ring-stacking interactions supported by C-H...Cl interactions with solvent molecules; a further ring-stacking interaction exists between the two Schiff base ligands of each molecule. PMID:26942435

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

    NASA Astrophysics Data System (ADS)

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

    2015-02-01

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

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

    PubMed

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

    2015-02-25

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

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

    PubMed

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

    2014-08-14

    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 (1)H 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.

  16. 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.

  17. Synthesis and Characterization with Antineoplastic, Biochemical, Cytotoxic, and Antimicrobial Studies of Schiff Base Cu(II) Ion Complexes

    PubMed Central

    Haque, M. M.; Kudrat-E-Zahan, Md.; Banu, Laila Arjuman; Islam, Md. Shariful; Islam, M. S.

    2015-01-01

    Copper(II) complexes containing two Schiff base ligands derived from 2-hydroxybenzaldehyde with 2-aminophenol and 3-aminophenol have been synthesized and characterized by means of analytical, magnetic, and spectroscopic methods. Bacteria, fungus, Entamoeba histolytica, and antineoplastic activities of the synthesized complexes have been determined by monitoring the parameters cell growth inhibition, survival time of tumour mice, time-body relation, causing of intraperitoneal cells and macrophages, alkaline phosphatase activity, hematological effect, and biopsy of tumour. PMID:26294901

  18. Synthesis and second-order nonlinear optical properties of new copper(II), nickel(II), and zinc(II) Schiff-base complexes. Toward a role of inorganic chromosphores for second harmonic generation

    SciTech Connect

    Lacroix, P.G.; Di Bella, S.; Ledoux, I.

    1996-02-01

    A new Schiff-base ligand based on the condensation of diaminomaleonitrile and 4-(diethylamino)salicylaldehyde is reported with its copper, nickel, and zinc complexes. Their second-order nonlinear optical properties are investigated by electric field induced second harmonic (EFISH) and ZINDO quantum-chemical calculation to probe the role of the metal center in the nonlinearity. All of the complexes exhibit a second-order nonlinear response that is larger than that of the ligand with an hyperpolarizability {beta} value of 400 ({+-}100) 10{sup -30} cm{sup 5} esu{sup -1} for the zinc derivative at 1.34 {mu}m. Theoretical calculations indicate that the two-level model is inadequate to describe the nonlinearity in such systems. 41 refs., 3 figs., 2 tabs.

  19. 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 [τ = 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.

  20. Synthesis, spectroscopy, electrochemistry and thermogravimetry of copper(II) tridentate Schiff base complexes, theoretical study of the structures of compounds and kinetic study of the tautomerism reactions by ab initio calculations

    NASA Astrophysics Data System (ADS)

    Kianfar, Ali Hossein; Ramazani, Shapour; Fath, Roghaye Hashemi; Roushani, Mahmoud

    2013-03-01

    Attempts to spectroscopic and structural study of copper complexes, some Cu(II) Schiff base complexes were synthesized and characterized by means of electronic, IR, 1HNMR spectra and elemental analysis. The thermal analyses of the complexes were investigated and the first order kinetic parameters were derived for them. The cyclic voltammetric studies in acetonitrile were proposed a monomeric structure for complexes. The structures of compounds were determined by ab initio calculations. In the solid state, the ligands exist as keto-amine/enol-imine tautomeric forms with an intramolecular hydrogen bond (Nsbnd H⋯O) between amine and carbonyl group. The kinetic studies of the tautomerism and equilibrium constant of the reactions were calculated using transition state theory. The optimized molecular geometry and atomic charges were calculated using MP2 method with 6-31G(d) basis set for H, C, N and O atoms and LANL2DZ for the Cu atom. The results suggested that, in the complexes, Cu(II) ion is in pseudo square-planar NO3 coordination geometry. Also the bond lengths and angles were studied and compared.

  1. 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 α-glucosidase inhibitory activity than free Schiff base ligand.

  2. 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 α-glucosidase inhibitory activity than free Schiff base ligand.

  3. 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.

  4. Designed synthesis of copper(II) and nickel(II) complexes with a tridentate N2O donor Schiff base: Modulation of crystalline architectures through Csbnd H⋯π and anion⋯π 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⋯π interactions in 2 gives rise to one dimensional chain structure. Complex 3 shows two Csbnd H⋯π interactions and one anion⋯π interactions which leads to a two dimensional layer structure. Each mononuclear unit of 4 has two Csbnd H⋯π interactions along b axis to form a double strand one dimensional array of the molecules in crystal packing.

  5. Mixed ligand copper(II) complexes of 1,10-phenanthroline with tridentate phenolate/pyridyl/(benz)imidazolyl Schiff base ligands: covalent vs non-covalent DNA binding, DNA cleavage and cytotoxicity.

    PubMed

    Rajarajeswari, Chandrasekaran; Ganeshpandian, Mani; Palaniandavar, Mallayan; Riyasdeen, Anvarbatcha; Akbarsha, Mohammad Abdulkadher

    2014-11-01

    A series of copper(II) complexes of the types [Cu(L)(phen)](ClO4) 1-2, where HL is a tridentate ligand with two nitrogen and one oxygen donor atoms (2NO) such as 2-(2-(1H-benzimidazol-2-yl)ethyliminomethyl)phenol (HL1) and 2-(2-(1H-benzimidazol-2-yl)ethyl-imino)methyl)-4-methylphenol (HL2), phen is 1,10-phenanthroline and [Cu(L)(phen)](ClO4)23-6, where L is a tridentate ligand with three nitrogen donor atoms (3N) such as (2-pyridin-2-ylethyl)pyridin-2-ylmethyleneamine (L3), 2-(1H-benzimidazol-2-yl)ethyl)-pyridin-2-yl-methyleneamine (L4), 2-(1H-benzimidazol-2-yl)ethyl)(1H-imidazol-2-ylmethylene)-amine (L5) and 2-(1H-benzimidazol-2-yl)ethyl)(4,4a-dihydroquinolin-2-ylmethylene)amine (L6), has been isolated and characterized by different spectral techniques. In single crystal X-ray structures, 1 possesses square pyramidal distorted trigonal bipyramidal (SPDTBP), geometry whereas 3 and 4 possess trigonal bipyramidal distorted square pyramidal (TBDSP) geometry. UV-Vis and fluorescence spectral studies reveal that the complexes 1-6 bind non-covalently to calf thymus DNA more strongly than the corresponding covalently bound chlorido complexes [Cu(2NO)Cl] 1a-2a and [Cu(3N)Cl2] 3a-6a. On prolonged incubation, all the complexes 1-6 exhibit double strand cleavage of supercoiled (SC) plasmid DNA in the absence of an activator. Also, they exhibit cytotoxicity against human breast cancer cell lines (HBL-100) more potent than their corresponding chlorido complexes 1a-6a, and have the potential to act as efficient cytotoxic drugs. PMID:25199844

  6. 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.

  7. Transition Metal Ion Complexes of Schiff-bases. Synthesis, Characterization and Antibacterial Properties

    PubMed Central

    Munawar, Asifa; Supuran, Claudiu T.

    2001-01-01

    Some novel transition metal [Co(II), Cu(II), Ni(II) and Zn(II)] complexes of substituted pyridine Schiff-bases have been prepared and characterized by physical, spectral and analytical data. The synthesized Schiff-bases act as deprotonated tridentate for the complexation reaction with Co(II), Ni(II) and Zn(II) ions. The new compounds, possessing the general formula [M(L)2] where [M=Co(II), Cu(II), Ni(II) and Zn(II) and HL=HL1, HL2, HL3 and HL4] show an octahedral geometry. In order to evaluate the effect of metal ions upon chelation, the Schiff bases and their complexes have been screened for antibacterial activity against the strains such as Escherichia coli,Staphylococcus aureus, and Pseudomonas aeruginosa. The complexed Schiff bases have shown to be more antibacterial against one more bacterial species as compared to uncomplexed Schiff-bases. PMID:18475987

  8. Synthesis, characterization and antimicrobial studies of Schiff base complexes

    NASA Astrophysics Data System (ADS)

    Zafar, Hina; Ahmad, Anis; Khan, Asad U.; Khan, Tahir Ali

    2015-10-01

    The Schiff base complexes, MLCl2 [M = Fe(II), Co(II), Ni(II), Cu(II) and Zn(II)] have been synthesized by the template reaction of respective metal ions with 2-acetylpyrrole and 1,3-diaminopropane in 1:2:1 M ratio. The complexes have been characterized by elemental analyses, ESI - mass, NMR (1H and 13C), IR, XRD, electronic and EPR spectral studies, magnetic susceptibility and molar conductance measurements. These studies show that all the complexes have octahedral arrangement around the metal ions. The molar conductance measurements of all the complexes in DMSO indicate their non-electrolytic nature. The complexes were screened for their antibacterial activity in vitro against Gram-positive (Streptococcus pyogenes) and Gram-negative (Klebsiella pneumoniae) bacteria. Among the metal complexes studied the copper complex [CuLCl2], showed highest antibacterial activity nearly equal to standard drug ciprofloxacin. Other complexes also showed considerable antibacterial activity. The relative order of activity against S. Pyogenes is as Cu(II) > Zn(II) > Co(II) = Fe(II) > Ni(II) and with K. Pneumonia is as Cu(II) > Co(II) > Zn(II) > Fe(II) > Ni(II).

  9. Synthesis, spectroscopic studies and inhibitory activity against bacteria 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.

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

    NASA Astrophysics Data System (ADS)

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

    2015-04-01

    Two series of new mono and binuclear complexes with a Schiff base ligand derived from the condensation of 3-acetylcoumarine and diethylenetriamine, in the molar ratio 2:1 have been prepared. The ligand was characterized by elemental analysis, IR, UV-visible, 1H-NMR and mass spectra. The reaction of the Schiff base ligand with cobalt(II), nickel(II), copper(II), zinc(II) and oxovanadium(IV) lead to mono or binuclear species of cyclic or macrocyclic complexes, depending on the mole ratio of metal to ligand and as well as on the method of preparation. The Schiff base ligand behaves as a cyclic bidentate, tetradendate or pentaentadentae ligand. The formation of macrocyclic complexes depends significantly on the dimension of the internal cavity, the rigidity of the macrocycles, the nature of its donor atoms and on the complexing properties of the anion involved in the coordination. Electronic spectra and magnetic moments of the complexes indicate that the geometries of the metal centers are either square pyramidal or octahedral for acyclic or macro-cyclic complexes. The structures are consistent with the IR, UV-visible, ESR, 1H-NMR, mass spectra as well as conductivity and magnetic moment measurements. The Schiff base ligand and its metal complexes were tested against two pathogenic bacteria as Gram-positive and Gram-negative bacteria as well as one kind of fungi. Most of the complexes exhibit mild antibacterial and antifungal activities against these organisms.

  11. Reversible Formation and Transmetalation of Schiff-Base Complexes in Subcomponent Self-Assembly Reactions.

    PubMed

    Lewing, Dennis; Koppetz, Hannah; Hahn, F Ekkehardt

    2015-08-01

    Dinuclear complexes [Zn2(NS,NS)2] 3 and [Ni2(NS,NS)2] 6 bearing Schiff-base ligands featuring two NS donor groups were obtained in subcomponent self-assembly reactions using nickel or zinc as template metals. Several transmetalation reactions starting from 3 or 6 yielded the complexes [Pd2(NS,NS)2] 4 and [Co2(NS,NS)2] 5, and their molecular structures were determined by X-ray diffraction. Starting from the mononuclear complex [Ni(NS/NOH)2] 9 featuring a coordinated NS Schiff base and a free NOH Schiff base, completely reversible thermodynamically controlled imine bond formation was observed leading to complex [Ni2(NS,NS)2] 6 and the free Schiff -base ligand NOH,NOH 10.

  12. Synthesis and Characterization of Metal Complexes with Schiff Base Ligands

    ERIC Educational Resources Information Center

    Wilkinson, Shane M.; Sheedy, Timothy M.; New, Elizabeth J.

    2016-01-01

    In order for undergraduate laboratory experiments to reflect modern research practice, it is essential that they include a range of elements, and that synthetic tasks are accompanied by characterization and analysis. This intermediate general chemistry laboratory exercise runs over 2 weeks, and involves the preparation of a Schiff base ligand and…

  13. Synthesis, spectroscopic identification, thermal, potentiometric and antibacterial activity studies of 4-amino-5-mercapto-S-triazole Schiff's base complexes

    NASA Astrophysics Data System (ADS)

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

    2015-05-01

    Complexes of manganese(II), cobalt(II), nickel(II), copper(II) and zinc(II) of general composition [M(L)2] have been synthesized [L = 4-pyridin-2-yl-methylene amino-4H-1,2,4-triazole-3-thiol]. The elemental analyses, molar conductance, spectral (IR, UV-Vis, 1H NMR, mass), magnetic moment and thermal measurements studies of the compounds led to the conclusion that the ligand acts as a tridentate manner (SNN). The molar conductance of the metal complexes in fresh solution of DMSO lies in the range of 8.34-10.46 Ω-1 cm2 mol-1 indicating their non-electrolytic behavior. On the basis of analytical and spectroscopic techniques, octahedral geometry of the complexes was proposed. The Schiff base acts as tridentate ligand coordinated through deprotonated thiolic sulfur, azomethine nitrogen and pyridine nitrogen atoms. The ligand field parameters were calculated for Co(II), Ni(II) and Cu(II) complexes and their values were found in the range reported for a octahedral structure. The data show that the complexes have composition of ML2 type. The activation of thermodynamic parameters are calculated using Coast-Redfern, Horowitz-Metzger (HM), Piloyan-Novikova (PN) and Broido's equations. Protonation constants of Schiff base and stability constants of their binary metal complexes have been determined potentiometrically in 50% DMSO-water media at 25 °C and ionic strength 0.10 M potassium nitrate. Both the Schiff's base ligand and its complexes have been screened for antibacterial activities.

  14. 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.

  15. Synthesis, molecular modeling and spectroscopic characterization of nickel(II), copper(II), complexes of new 16-membered mixed-donor macrocyclic schiff base ligand incorporating a pendant alcohol function

    NASA Astrophysics Data System (ADS)

    Chandra, Sulekh; Ruchi; Qanungo, Kushal; Sharma, Saroj K.

    2011-09-01

    Complexes of Cu(II) and Ni(II) of the composition [M(L)X] [where M = Ni(II), Cu(II) and X = Cl -, NO 3-, CH 3COO -] were synthesized with 1,5-dioxo-9,10-diaza-3,ol-tribenzo-(7,6,10,11,14,15) peptadecane, a N 2O 2 macrocyclic ligand. The complexes were characterized by elemental analysis, molar conductance measurements, UV-vis, IR, 1H NMR, 13C NMR, EPR and molecular modeling studies. All the complexes are non-electrolyte in nature. On the basis of spectral studies, an octahedral geometry has been assigned for Ni(II) complexes and a tetragonal geometry for Cu(II) complexes.

  16. Mononuclear Ru(III) Schiff base complexes: Synthesis, spectral, redox, catalytic and biological activity studies

    NASA Astrophysics Data System (ADS)

    Priya, N. Padma; Arunachalam, S.; Manimaran, A.; Muthupriya, D.; Jayabalakrishnan, C.

    2009-04-01

    An octahedral ruthenium(III) Schiff base complexes of the type [RuX(EPh 3)(L)] (where, X = Cl/Br; E = As/P; L = dianion of the Schiff bases derived from acetoacetanilide with o-phenylenediamine and salicylaldehyde/ o-hydroxyacetophenone/ o-vanillin/2-hydroxy-1-naphthaldehyde) have been synthesized from the reactions of equimolar reactions of [RuX 3(EPh 3) 3] and Schiff bases in benzene. The new Ru(III) Schiff base complexes have been characterized by elemental analyses, FT-IR, electronic, 1H NMR and 13C NMR spectra, EPR spectral studies, powder X-ray diffraction (XRD) and electrochemical studies. The new complexes were found to be effective catalysts for aryl-aryl coupling and the oxidation of alcohols into their corresponding carbonyl compounds, respectively, using molecular oxygen atmosphere at ambient temperature. Further, the new Ru(III) Schiff base complexes were screened for their antibacterial activity against Pseudomonas aeruginosa, Vibrio cholera, Salomonella typhi and Staphylococcus aureaus.

  17. 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.

  18. Ni(II) complexes with Schiff bases derived from amino sugars.

    PubMed

    Costamagna, Juan; Lillo, Luis E; Matsuhiro, Betty; Noseda, Miguel D; Villagrán, Manuel

    2003-07-22

    It was found by 1H and 13C NMR spectroscopy that the Schiff base, 2-deoxy-2-(2-hydroxybenzaldimino)-D-glucopyranose exhibits enol-imine-keto-amine and anomeric equilibria in methanolic, and in dimethyl sulfoxide solutions. The reaction of the Schiff base with nickel acetate gave the bidentate, mononuclear Ni(II) complex that was characterized by spectroscopic methods and by cyclic voltammetry. The coordination of the Schiff base to the metal is through the enol-imine tautomeric form, and the anomeric equilibrium remains in dimethyl sulfoxide solutions. This complex was also obtained by reaction of D-glucosamine with Ni(II) salicylaldehydate. The same reaction was employed for the synthesis of bis-N-[2-deoxy-D-galactopyranosyl-2-(2-hydroxybenzaldiminate)]Ni(II). The small paramagnetic shifts of the 1H NMR resonances of the complexes suggest that paramagnetic species are present in low proportions.

  19. Synthesis, characterization and antibacterial studies of ruthenium(III) complexes derived from chitosan schiff base.

    PubMed

    Vadivel, T; Dhamodaran, M

    2016-09-01

    Chitosan can be modified chemically by condensation reaction of deacetylated chitosan with aldehyde in homogeneous phase. This condensation is carried by primary amine (NH2) with aldehyde (CHO) to form corresponding schiff base. The chitosan biopolymer schiff base derivatives are synthesized with substituted aldehydes namely 4-hydroxy-3-methoxy benzaldehyde, 2-hydroxy benzaldehyde, and 2-hydroxy-3-methoxy benzaldehyde, becomes a complexing agent or ligand. The Ruthenium(III) complexes were obtained by complexation of Ruthenium with schiff base ligands and this product exhibits as an excellent solubility and more biocompatibility. The novel series of schiff base Ruthenium(III) complexes are characterized by Elemental analysis, FT-IR spectroscopy, and Thermo-gravimetric analysis (TGA). The synthesized complexes have been subjected to antibacterial study. The antibacterial results indicated that the antibacterial activity of the complexes were more effective against Gram positive and Gram negative pathogenic bacteria. These findings are giving suitable support for developing new antibacterial agent and expand our scope for applications.

  20. Self-assembled copper(II) metallacycles derived from asymmetric Schiff base ligands: efficient hosts for ADP/ATP in phosphate buffer.

    PubMed

    Kumar, Amit; Pandey, Rampal; Kumar, Ashish; Gupta, Rakesh Kumar; Dubey, Mrigendra; Mohammed, Akbar; Mobin, Shaikh M; Pandey, Daya Shankar

    2015-10-21

    Novel asymmetric Schiff base ligands 2-{[3-(3-hydroxy-1-methyl-but-2-enylideneamino)-2,4,6-trimethylphenylimino]-methyl}-phenol (H2L(1)) and 1-{[3-(3-hydroxy-1-methyl-but-2-enylideneamino)-2,4,6-trimethylphenylimino]-methyl}-naphthalen-2-ol (H2L(2)) possessing dissimilar N,O-chelating sites and copper(ii) metallacycles (CuL(1))4 (1) and (CuL(2))4 (2) based on these ligands have been described. The ligands and complexes have been thoroughly characterized by satisfactory elemental analyses, and spectral (IR, (1)H, (13)C NMR, ESI-MS, UV/vis) and electrochemical studies. Structures of H2L(2) and 1 have been unambiguously determined by X-ray single crystal analyses. The crystal structure of H2L(2) revealed the presence of two distinct N,O-chelating sites on dissimilar cores (naphthalene and β-ketoaminato groups) offering a diverse coordination environment. Metallacycles 1 and 2 having a cavity created by four Cu(ii) centres coordinated in a homo- and heteroleptic fashion with respective ligands act as efficient hosts for adenosine-5'-diphosphate (ADP) and adenosine-5'-triphosphate (ATP) respectively, over other nucleoside polyphosphates (NPPs). The disparate sensitivity of these metallacycles toward ADP and ATP has been attributed to the size of the ligands assuming diverse dimensions and spatial orientations. These are attuned for π-π stacking and electrostatic interactions suitable for different guest molecules under analogous conditions, metallacycle 1 offers better orientation for ADP, while 2 for ATP. The mechanism of the host-guest interaction has been investigated by spectral and electrochemical studies and supported by molecular docking studies. PMID:26373609

  1. Self-assembled copper(II) metallacycles derived from asymmetric Schiff base ligands: efficient hosts for ADP/ATP in phosphate buffer.

    PubMed

    Kumar, Amit; Pandey, Rampal; Kumar, Ashish; Gupta, Rakesh Kumar; Dubey, Mrigendra; Mohammed, Akbar; Mobin, Shaikh M; Pandey, Daya Shankar

    2015-10-21

    Novel asymmetric Schiff base ligands 2-{[3-(3-hydroxy-1-methyl-but-2-enylideneamino)-2,4,6-trimethylphenylimino]-methyl}-phenol (H2L(1)) and 1-{[3-(3-hydroxy-1-methyl-but-2-enylideneamino)-2,4,6-trimethylphenylimino]-methyl}-naphthalen-2-ol (H2L(2)) possessing dissimilar N,O-chelating sites and copper(ii) metallacycles (CuL(1))4 (1) and (CuL(2))4 (2) based on these ligands have been described. The ligands and complexes have been thoroughly characterized by satisfactory elemental analyses, and spectral (IR, (1)H, (13)C NMR, ESI-MS, UV/vis) and electrochemical studies. Structures of H2L(2) and 1 have been unambiguously determined by X-ray single crystal analyses. The crystal structure of H2L(2) revealed the presence of two distinct N,O-chelating sites on dissimilar cores (naphthalene and β-ketoaminato groups) offering a diverse coordination environment. Metallacycles 1 and 2 having a cavity created by four Cu(ii) centres coordinated in a homo- and heteroleptic fashion with respective ligands act as efficient hosts for adenosine-5'-diphosphate (ADP) and adenosine-5'-triphosphate (ATP) respectively, over other nucleoside polyphosphates (NPPs). The disparate sensitivity of these metallacycles toward ADP and ATP has been attributed to the size of the ligands assuming diverse dimensions and spatial orientations. These are attuned for π-π stacking and electrostatic interactions suitable for different guest molecules under analogous conditions, metallacycle 1 offers better orientation for ADP, while 2 for ATP. The mechanism of the host-guest interaction has been investigated by spectral and electrochemical studies and supported by molecular docking studies.

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

    NASA Astrophysics Data System (ADS)

    Galić, Nives; Cimerman, Zvjezdana; Tomišić, Vladislav

    2008-12-01

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

  3. Synthesis, fluorescence study and biological evaluation of three Zn(II) complexes with Paeonol Schiff base

    NASA Astrophysics Data System (ADS)

    Qin, Dong-dong; Yang, Zheng-yin; Qi, Gao-fei

    2009-10-01

    The synthesis of three Paeonol Schiff base ligand and their Zn(II) complexes are reported. The complexes were fully characterized by IR, 1H NMR, elemental analysis and molar conductivity. The experiment results show the three Zn(II) complexes can emit bright fluorescence at room temperature in DMF solution and solid state. The fluorescence quantum yields ( Φ) of three Schiff base ligands and their Zn(II) complexes were calculated using quinine sulfate as the reference with a known ΦR of 0.546 in 1.0N sulfuric acid. Furthermore, in order to develop these Zn(II) complexes' biological value, the antioxidant activities against hydroxyl radicals (OH rad ) were evaluated. The results show the three complexes possess excellent ability to scavenge hydroxyl radicals.

  4. [Photochromic properties of complexes of curcumin aniline schiff base with rare earth].

    PubMed

    Song, Yu-Min; Yang, Mei-Ling; Ma, Jun-Huai; Zhang, Yu-Mei

    2013-12-01

    Using Ce, La, Nd (III) nitrate and a curcumin aniline schiff base and a curcumin bis (4-methyl aniline) schiff base as raw materials, six complexes were synthesized. Through the molar conductance, IR, TG-DTA and element analysis motheds, the structures of complexes were characterized. Moreover, the properties of UV-Visible spectra and photochromic properties of the complex, and the solvatechromic performance in organic solvents were explored. The experiments showed that the complexes have good photochromic and solvate-chromic properties. The fluorescence intensity and UV-Visible spectra intensity were reduced under exposure,and the color of the complex solution became light. The complexes have different UV-Visible spectra in difference organic solvents. The relationship between photochromic properties and time was also studied.

  5. Influence of Schiff base and lanthanide metals on the synthesis, stability, and reactivity of monoamido lanthanide complexes bearing two Schiff bases.

    PubMed

    Han, Fubin; Teng, Qiaoqiao; Zhang, Yong; Wang, Yaorong; Shen, Qi

    2011-03-21

    The monoamido lanthanide complexes stabilized by Schiff base ligand L(2)LnN(TMS)(2) (L = 3,5-Bu(t)(2)-2-(O)-C(6)H(2)CH═N-8-C(9)H(6)N, Ln = Yb (1), Y (2), Eu (3), Nd (4), and La (5)) were synthesized in good yields by the reactions of Ln[N(TMS)(2)](3) with 1.8 equiv of HL in hexane at room temperature. It was found that the stability of 1-5 depends greatly on the size of the lanthanide metals with the increasing trend of Yb ≈ Y < Nd < La. The amine elimination of Ln[N(TMS)(2)](3) with the bulky bidentate Schiff base HL' (L' = 3,5-Bu(t)(2)-2-(O)-C(6)H(2)CH═N-2,6-Pr(i)(2)-C(6)H(3)) afforded the monoamido lanthanide complexes L'(2)LnN(TMS)(2) (Ln = Yb (9), Y (10), Nd (11), and La (12)). While the amine elimination with the less bulky Schiff base HL'' (L'' = 3,5-Bu(t)(2)-2-(O)-C(6)H(2)CH═N-2,6-Me(2)-C(6)H(3)) yielded the desired monoamido complexes with the small metals of Y and Yb, L''(2)LnN(TMS)(2) (Ln = Yb (13) and Y (14)), and the more stable tris-Schiff base complexes with the large metals of La and Nd, yielded L''(3)Ln as the only product. Complexes 1-14 were fully characterized including X-ray crystal structural analysis. Complexes 1-5, 10, and 14 can serve as the efficient catalysts for addition of amines to carbodiimides, and the catalytic activity is greatly affected by the lanthanide metals with the active sequence of Yb < Y < Eu ≈ Nd ≈ La.

  6. Synthesis, characterization, spectroscopic and theoretical studies of new zinc(II), copper(II) and nickel(II) complexes based on imine ligand containing 2-aminothiophenol moiety

    NASA Astrophysics Data System (ADS)

    Shafaatian, Bita; Mousavi, S. Sedighe; Afshari, Sadegh

    2016-11-01

    New dimer complexes of zinc(II), copper(II) and nickel(II) were synthesized using the Schiff base ligand which was formed by the condensation of 2-aminothiophenol and 2-hydroxy-5-methyl benzaldehyde. This tridentate Schiff base ligand was coordinated to the metal ions through the NSO donor atoms. In order to prevent the oxidation of the thiole group during the formation of Schiff base and its complexes, all of the reactions were carried out under an inert atmosphere of argon. The X-ray structure of the Schiff base ligand showed that in the crystalline form the SH groups were oxidized to produce a disulfide Schiff base as a new double Schiff base ligand. The molar conductivity values of the complexes in dichloromethane implied the presence of non-electrolyte species. The fluorescence properties of the Schiff base ligand and its complexes were also studied in dichloromethane. The products were characterized by FT-IR, 1H NMR, UV/Vis spectroscopies, elemental analysis, and conductometry. The crystal structure of the double Schiff base was determined by single crystal X-ray diffraction. Furthermore, the density functional theory (DFT) calculations were performed at the B3LYP/6-31G(d,p) level of theory for the determination of the optimized structures of Schiff base complexes.

  7. Synthesis and Fluorescence Properties of Eu(3+), Tb(3+) Complexes with Schiff Base Derivatives.

    PubMed

    Liu, Yanhong; Kong, Weihua; Yang, Zehui; Dai, Ming; Shi, Ling; Guo, Dongcai

    2016-03-01

    Novel Schiff base ligands derived from N'-benzylidene-benzohydrazide (substituted by -H, -CH3, -OCH3, -Cl) and 2-chloro-N-phenylacetamide were synthesized. The solid complexes of rare earth (Eu, Tb) nitrate with these Schiff base ligands were synthesized and characterized by elemental analysis, EDTA titrimetric analysis, thermal analysis, infrared spectra and UV-Vis spectra analysis. The fluorescence properties of rare earth (Eu, Tb) complexes in solid were studied. Under the excitation of ultraviolet light, these complexes exhibited characteristic emission of europium and terbium ions. The results showed that the ligand favored energy transfer to the emitting energy of Eu and Tb ions. Effects of different ligands on the fluorescence intensity of rare earth (Eu, Tb) complexes had been discussed. The electrochemical properties of rare earth (Eu, Tb) complexes were also investigated.

  8. Synthesis and Fluorescence Properties of Eu(3+), Tb(3+) Complexes with Schiff Base Derivatives.

    PubMed

    Liu, Yanhong; Kong, Weihua; Yang, Zehui; Dai, Ming; Shi, Ling; Guo, Dongcai

    2016-03-01

    Novel Schiff base ligands derived from N'-benzylidene-benzohydrazide (substituted by -H, -CH3, -OCH3, -Cl) and 2-chloro-N-phenylacetamide were synthesized. The solid complexes of rare earth (Eu, Tb) nitrate with these Schiff base ligands were synthesized and characterized by elemental analysis, EDTA titrimetric analysis, thermal analysis, infrared spectra and UV-Vis spectra analysis. The fluorescence properties of rare earth (Eu, Tb) complexes in solid were studied. Under the excitation of ultraviolet light, these complexes exhibited characteristic emission of europium and terbium ions. The results showed that the ligand favored energy transfer to the emitting energy of Eu and Tb ions. Effects of different ligands on the fluorescence intensity of rare earth (Eu, Tb) complexes had been discussed. The electrochemical properties of rare earth (Eu, Tb) complexes were also investigated. PMID:26658796

  9. Synthesis, spectroscopy, electrochemistry and thermal study of vanadyl tridentate Schiff base complexes

    NASA Astrophysics Data System (ADS)

    Kianfar, Ali Hossein; Paliz, Marzeh; Roushani, Mahmoud; Shamsipur, Mojtaba

    2011-11-01

    The VO(IV) complexes of tridentate ONO Schiff ligands were synthesised and characterized by IR, UV-vis and elemental analysis. 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 < NO 2 and H < Cl. The thermogravimetry (TG) and differential thermoanalysis (DTA) of the VO(IV) complexes were carried out in the range of 20-700 °C. The VOL 1(OH 2) decomposed in two steps whereas the remaining six complexes decomposed in three steps. The thermal decomposition of these complexes is closely related to the nature of the Schiff base ligands and proceeds via first order kinetics.

  10. Docking of ethanamine Schiff base imines & metal (II) complexes, cytotoxicity & DNA interaction studies

    NASA Astrophysics Data System (ADS)

    Sujarani, S.; Ramu, A.

    2015-01-01

    The present study deals with a series of biologically and stereo chemically important novel transition metal (II) Schiff base chelates. The Cu (II), Co (II), Mn (II) and Ni (II) ions containing complexes were synthesized by using diphenylethanamine and 2-hydroxy/2, 4-dihydroxy/2-hydroxy-4-methoxybenzaldehydes. The synthesized complexes were characterized using micro analytical, IR, NMR, ESI-Mass, UV-Visible, cyclic voltammetry and the EPR spectroscopic techniques. The spectral data evidenced the action of ligands as a neutral bidentate Schiff bases, coordinating through azomethine nitrogen and oxygen atom of hydroxyl group. The interaction studies revealed the groove binding nature of complexes with CT-DNA. The ligand and synthesized metal complexes showed cytotoxicity against cancerous cells. The strong binding affinity of the imine and metal complexes was also confirmed by molecular docking studies.

  11. Kit for unsymmetric dinucleating double-Schiff-base ligands: facile access to a versatile new ligand system and its first heterobimetallic copper-zinc complex.

    PubMed

    Roth, Arne; Spielberg, Eike T; Plass, Winfried

    2007-05-28

    The synthetic route toward new unsymmetric compartmental "end-off" Schiff-base ligands in a straightforward two-step reaction of 2,6-diformyl-4-methylphenol and two different amine components is presented. To demonstrate the versatility of this method, we have synthesized two different single-Schiff-base proligands, Hbpahmb and Hphmb, utilizing (2-aminoethyl)bis(2-pyridylmethyl)amine and (2-aminomethyl)pyridine, respectively. Subsequent reaction with thiosemicarbazide as the second amine component leads to the novel unsymmetric double-Schiff-base ligands {1-[3-[2-[bis(pyridin-2-ylmethyl)amino]ethyliminomethyl]-2-hydroxy-5-methylphenyl]methylidene}hydrazine carbothioamide (H2bpamptsc) and {1-[3-(pyridin-2-ylmethyliminomethyl)-2-hydroxy-5-methylphenyl]methylidene}hydrazine carbothioamide (H2pmptsc). Both ligands provide two distinctly different coordination pockets: a rigid tridentate N,O,S donor set of the hydrazide compartment versus a rather flexible pentadentate (H2bpamptsc) or tridentate (H2pmptsc) nitrogen-rich chelating side arm. The reaction of the ligand H2bpamptsc with zinc(II) acetate and copper(II) perchlorate yields the heterobinuclear Cu-Zn complex [CuZn(bpamptsc)(mu2,eta1-OAc)(MeCN)](ClO4) (1). PMID:17461577

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

    PubMed Central

    Amzoiu, Emilia; Spînu, Cezar Ionuţ

    2014-01-01

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

  13. Synthesis, spectroscopic, structural characterization, electrochemical and antimicrobial activity studies of the Schiff base ligand and its transition metal complexes

    NASA Astrophysics Data System (ADS)

    Aslantaş, Mehmet; Kendi, Engin; Demir, Necmettin; Şabik, Ali E.; Tümer, Mehmet; Kertmen, Metin

    2009-10-01

    In this study, the Schiff base ligand trans-N,N'-bis[(2,4-dichlorophenyl) methylidene] cyclohexane-1,2-diamine (L) and its copper(II), nickel(II) and palladium(II) transition metal complexes were prepared and characterized by the analytical and spectroscopic methods. The 1H( 13C) NMR spectra of the ligand and its diamagnetic complexes were recorded in DMSO-d 6 solvent and obtained data confirm that the nitrogen atoms of the imine groups coordinated to the metal ions. Electrochemical properties of the ligand and its metal complexes were investigated in the DMF solvent at the 100 and 250 mV s -1 scan rates. The ligand and metal complexes showed both reversible and irreversible processes at these scan rates. The single crystal of the ligand (L) was obtained from MeOH solution, and its crystal structure was determined by X-ray diffraction. The C-H⋯Cl hydrogen bonding interactions in the molecule were seen which increase the stability of the crystal structure. The antimicrobial activity studies of the ligand and its metal complexes were carried out by using the various bacteria and fungi.

  14. Tuning cobalt(III) Schiff base complexes as activated protein inhibitors.

    PubMed

    Heffern, Marie C; Reichova, Viktorie; Coomes, Joseph L; Harney, Allison S; Bajema, Elizabeth A; Meade, Thomas J

    2015-09-21

    Cobalt(III) Schiff base complexes ([Co(acacen)(L)2](+), where L = NH3) inhibit histidine-containing proteins through dissociative exchange of the labile axial ligands (L). This work investigates axial ligand exchange dynamics of [Co(acacen)(L)2](+) complexes toward the development of protein inhibitors that are activated by external triggers such as light irradiation. We sought to investigate ligand exchange dynamics to design a Co(III) complex that is substitutionally inert under normal physiological conditions for selective activation. Fluorescent imidazoles (C3Im) were prepared as axial ligands in [Co(acacen)(L)2](+) to produce complexes (CoC3Im) that could report on ligand exchange and, thus, complex stability. These fluorescent imidazole reporters guided the design of a new dinuclear Co(III) Schiff base complex containing bridging diimidazole ligands, which exhibits enhanced stability to ligand exchange with competing imidazoles and to hydrolysis within a biologically relevant pH range. These studies inform the design of biocompatible Co(III) Schiff base complexes that can be selectively activated for protein inhibition with spatial and temporal specificity.

  15. In vitro anticancer activities of Schiff base and its lanthanum complex.

    PubMed

    Neelima; Poonia, Kavita; Siddiqui, Sahabjada; Arshad, Md; Kumar, Dinesh

    2016-02-15

    Schiff base metal complexes are well-known to intercalate DNA. The La(III) complexes have been synthesized such that they hinder with the role of the topoisomerases, which control the topology of DNA during the cell-division cycle. Although several promising chemotherapeutics have been developed, on the basis of Schiff base metal complex DNA intercalating system they did not proceed past clinical trials due to their dose-limiting toxicity. Herein, we discuss an alternative compound, the La(III) complex, [La(L(1))2Cl3]·7H2O based on a Schiff base ligand 2,3-dihydro-1H-indolo-[2,3-b]-phenazin-4(5H)-ylidene)benzothiazole-2-amine (L(1)), and report in vitro cell studies. Results of antitumor activity using cell viability assay, reactive oxygen species (ROS) generation and nuclear condensation in PC-3 (Human, prostate carcinoma) cells show that the metal complex is more potent than ligand. La(III) complexes have been synthesized by reaction of lanthanum(III) salt in 1:2M ratio with ligands L(1) and 3-(ethoxymethylene)-2,3-dihydro-1H-indolo[2,3-b]-phenazin-4(5H)-ylidene)benzathiazole-2-amine (L(2)) in methanol. The ligands and their La(III) complexes were characterized by molar conductance, magnetic susceptibility, elemental analyses, FT-IR, UV-Vis, (1)H/(13)C NMR, thermogravimetric, XRD, and SEM analysis.

  16. In vitro anticancer activities of Schiff base and its lanthanum complex

    NASA Astrophysics Data System (ADS)

    Neelima; Poonia, Kavita; Siddiqui, Sahabjada; Arshad, Md; Kumar, Dinesh

    2016-02-01

    Schiff base metal complexes are well-known to intercalate DNA. The La(III) complexes have been synthesized such that they hinder with the role of the topoisomerases, which control the topology of DNA during the cell-division cycle. Although several promising chemotherapeutics have been developed, on the basis of Schiff base metal complex DNA intercalating system they did not proceed past clinical trials due to their dose-limiting toxicity. Herein, we discuss an alternative compound, the La(III) complex, [La(L1)2Cl3]·7H2O based on a Schiff base ligand 2,3-dihydro-1H-indolo-[2,3-b]-phenazin-4(5H)-ylidene)benzothiazole-2-amine (L1), and report in vitro cell studies. Results of antitumor activity using cell viability assay, reactive oxygen species (ROS) generation and nuclear condensation in PC-3 (Human, prostate carcinoma) cells show that the metal complex is more potent than ligand. La(III) complexes have been synthesized by reaction of lanthanum(III) salt in 1:2 M ratio with ligands L1 and 3-(ethoxymethylene)-2,3-dihydro-1H-indolo[2,3-b]-phenazin-4(5H)-ylidene)benzathiazole-2-amine (L2) in methanol. The ligands and their La(III) complexes were characterized by molar conductance, magnetic susceptibility, elemental analyses, FT-IR, UV-Vis, 1H/13C NMR, thermogravimetric, XRD, and SEM analysis.

  17. 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)Ǻ, b=9.479(3)Ǻ, c=12.425(4)Ǻ, α=101.636(3)°, β=99.633(3)°, γ=94.040(3)°, V=795.0(4)Ǻ(3), Z=2, F(000)=352, Dc=1.405 mg/m(3), μ=0.099 mm(-1), R=0.0378, and wR=0.0967. The spectral results show that the Schiff base ligand acts as a bidentate donor coordinating through the azomethine nitrogen and the carbonyl oxygen atoms. The geometrical structures of these complexes are found to be square planar. Antimicrobial studies indicate that these complexes exhibit better activity than the ligand. The anticancer activities of the complexes have also been studied towards human cervical cancer cell line (HeLa), Colon Cancer Cells (HCT116) and Epidermoid Carcinoma Cells (A431) and it was found that the [Pt(L3)Cl2] complex is more active.

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

    NASA Astrophysics Data System (ADS)

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

    2015-06-01

    The platinum complexes of Schiff base ligands derived from 4-aminoantipyrine and a few substituted aldehydes were synthesized and characterized by elemental analysis, mass, 1H NMR, IR, electronic spectra, molar conductance, and powder XRD. The structure of one of the ligands L5 was confirmed by a single crystal XRD analysis. The Schiff base ligand crystallized in the triclinic, space group P-1 with a = 7.032(2) Ǻ, b = 9.479(3) Ǻ, c = 12.425(4) Ǻ, α = 101.636(3)°, β = 99.633(3)°, γ = 94.040(3)°, V = 795.0(4) Ǻ3, Z = 2, F(0 0 0) = 352, Dc = 1.405 mg/m3, μ = 0.099 mm-1, R = 0.0378, and wR = 0.0967. The spectral results show that the Schiff base ligand acts as a bidentate donor coordinating through the azomethine nitrogen and the carbonyl oxygen atoms. The geometrical structures of these complexes are found to be square planar. Antimicrobial studies indicate that these complexes exhibit better activity than the ligand. The anticancer activities of the complexes have also been studied towards human cervical cancer cell line (HeLa), Colon Cancer Cells (HCT116) and Epidermoid Carcinoma Cells (A431) and it was found that the [Pt(L3)Cl2] complex is more active.

  19. Novel polymer anchored Cr(III) Schiff base complexes: Synthesis, characterization and antimicrobial properties

    NASA Astrophysics Data System (ADS)

    Selvi, Canan; Nartop, Dilek

    2012-09-01

    New polymer-bound Schiff bases and Cr(III) complexes have been synthesized by the reaction of 4-benzyloxybenzaldehyde, polymer-bound with 2-aminophenol, 2-amino-4-chlorophenol and 2-amino-4-methylphenol. The structure of polymeric-Schiff bases and their Cr(III) complexes have been characterized by elemental analyses, magnetic measurements, IR, UV-Vis, TG-DTA and 1H-NMR. All these compounds have also been investigated for antibacterial activity by the well-diffusion method against Staphylococcus aureus (RSKK-07035), Shigella dysenteria type 10 (RSKK 1036), Listeria monocytogenes 4b(ATCC 19115, Escherichia coli (ATCC 1230), Salmonella typhi H (NCTC 901.8394), Staphylococcus epidermis (ATCC 12228), Brucella abortus (RSKK-03026), Micrococcs luteus (ATCC 93419, Bacillus cereus sp., Pseudomonas putida sp. and for antifungal activity against Candida albicans (Y-1200-NIH).

  20. Novel polymer anchored Cr(III) Schiff base complexes: synthesis, characterization and antimicrobial properties.

    PubMed

    Selvi, Canan; Nartop, Dilek

    2012-09-01

    New polymer-bound Schiff bases and Cr(III) complexes have been synthesized by the reaction of 4-benzyloxybenzaldehyde, polymer-bound with 2-aminophenol, 2-amino-4-chlorophenol and 2-amino-4-methylphenol. The structure of polymeric-Schiff bases and their Cr(III) complexes have been characterized by elemental analyses, magnetic measurements, IR, UV-Vis, TG-DTA and (1)H-NMR. All these compounds have also been investigated for antibacterial activity by the well-diffusion method against Staphylococcus aureus (RSKK-07035), Shigella dysenteria type 10 (RSKK 1036), Listeria monocytogenes 4b(ATCC 19115, Escherichia coli (ATCC 1230), Salmonella typhi H (NCTC 901.8394), Staphylococcus epidermis (ATCC 12228), Brucella abortus (RSKK-03026), Micrococcs luteus (ATCC 93419, Bacillus cereus sp., Pseudomonas putida sp. and for antifungal activity against Candida albicans (Y-1200-NIH). PMID:22622060

  1. Synthesis, interaction with DNA and antiproliferative activities of two novel Cu(II) complexes with Schiff base of benzimidazole

    NASA Astrophysics Data System (ADS)

    Song, Wen-Ji; Cheng, Jian-Ping; Jiang, Dong-Hua; Guo, Li; Cai, Meng-Fei; Yang, Hu-Bin; Lin, Qiu-Yue

    2014-03-01

    Two novel copper(II) complexes with Schiff base of benzimidazole [Cu(L)Cl]2·CH3OH have been synthesized. HL1 (N-(benzimidazol-2-ymethyl)-5-chlorosalicylideneimine, C15H11ClN3O) and HL2 (N-(benzimidazol-2-ymethyl)-salicylideneimine, C15H12N3O) are ligands of complex (1) and complex (2), respectively. The complexes were characterized by elemental analysis, IR, UV-Vis, TGA and X-ray diffraction. Within the complexes, Cu(II) ions were four coordinated by two nitrogen atom of azomethine and imine, one phenolic oxygen atom from HL and one chloride atom. A distorted quadrilateral structure was formed. Complex (1) crystallized in the triclinic crystal system. Results showed that π-π stacking effect occurred due to the existence of aromatic ring from Schiff base and hydrogen bonding between methanol and adjacent atoms. The DNA binding properties of the complexes were investigated by electronic absorption spectra, fluorescence spectra and viscosity measurements. Results indicated that complexes bound to DNA via partial intercalation mode. The DNA binding constants Kb/(L mol-1) were 1.81 × 104 (1), 1.37 × 104 (2), 6.27 × 103 (HL1) and 3.14 × 103 (HL2) at 298 K. The title complexes could quench the emission intensities of EB-DNA system significantly. The results of agarose gel electrophoresis indicated complex (1) could cleave supercoiled DNA through the oxidative mechanism. The inhibition ratios revealed that complex (1) and HL1 had strong antiproliferative activities against human breast cancer cells (MCF-7) lines and human colorectal cancer cells (COLO205) lines in vitro. The antiproliferative activities of complex (1) against MCF-7 lines (IC50 = 16.9 ± 1.5 μmol L-1) and against COLO205 lines (IC50 = 16.5 ± 3.4 μmol L-1) is much stronger than that of HL1, which had the potential to develop anti-cancer drug.

  2. Synthesis and spectral studies of metal complexes of a Schiff base derived from (2-amino-5-chlorophenyl)phenyl methanone.

    PubMed

    Mini, S; Sadasivan, V; Meena, S S; Bhatt, Pramod

    2015-01-01

    Some new complexes of Mn(II), Co(II), Ni(II), Cu(II), Zn(II), and Fe(III) with the Schiff base 5-chloro-2-(furan-2-yl methylamino)phenyl)phenyl methanone has been synthesized and characterized by elemental analysis, spectroscopic data including FT-IR, (1)H NMR, Electronic, ESI mass, Mössbauer & ESR. It has been found that the Schiff base behaves as a neutral bidentate N, O donor which chelates with the metal ions in 1:2 stoichiometry. Magnetic moment and electrolytic conductance data confirms this. The Schiff base and selected complexes were screened for antimicrobial activity. The complexes and the Schiff base were subjected to antioxidant study. The antitumor activity of Co(II) complex was tested by MTT assay. The result indicates the viability of the complex against tested cell lines.

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

    SciTech Connect

    Liu Li; Shao Mingwang; Wang Xiuhua

    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.

  4. Antibacterial and antifungal metal based triazole Schiff bases.

    PubMed

    Chohan, Zahid H; Hanif, Muhammad

    2013-10-01

    A new series of four biologically active triazole derived Schiff base ligands (L(1)-L(4)) and their cobalt(II), nickel(II), copper(II) and zinc(II) complexes (1-16) have been synthesized and characterized. The ligands were prepared by the condensation reaction of 3-amino-5-methylthio-1H-1,2,4-triazole with chloro-, bromo- and nitro-substituted 2-hydroxybenzaldehyde in an equimolar ratio. The antibacterial and antifungal bioactivity data showed the metal(II) complexes to be more potent antibacterial and antifungal than the parent Schiff bases against one or more bacterial and fungal species.

  5. Interaction of water-soluble amino acid Schiff base complexes with bovine serum albumin: Fluorescence and circular dichroism studies

    NASA Astrophysics Data System (ADS)

    Gharagozlou, Mehrnaz; Boghaei, Davar M.

    2008-12-01

    Fluorescence spectroscopy in combination with circular dichroism (CD) spectroscopy were used to investigate the interaction of water-soluble amino acid Schiff base complexes, [Zn(L 1,2)(phen)] where phen is 1,10-phenanthroline and H 2L 1,2 is amino acid Schiff base ligands, with bovine serum albumin (BSA) under the physiological conditions in phosphate buffer solution adjusted to pH 7.0. The quenching mechanism of fluorescence was suggested as static quenching according to the Stern-Volmer equation. Quenching constants were determined using the Stern-Volmer equation to provide a measure of the binding affinity between amino acid Schiff base complexes and BSA. The thermodynamic parameters Δ G, Δ H and Δ S at different temperatures (298, 310 and 318 K) were calculated. The results indicate that the hydrophobic and hydrogen bonding interactions play a major role in [Zn(L 1)(phen)]-BSA association, whereas hydrophobic and electrostatic interactions participate a main role in [Zn(L 2)(phen)]-BSA binding process. Binding studies concerning the number of binding sites and apparent binding constant Kb were performed by fluorescence quenching method. The distance R between the donor (BSA) and acceptor (amino acid Schiff base complexes) has been obtained utilizing fluorescence resonant energy transfer (FRET). Furthermore, CD spectra were used to investigate the structural changes of the BSA molecule with the addition of amino acid Schiff base complexes. The results indicate that the interaction of amino acid Schiff base complexes with BSA leads to changes in the secondary structure of the protein. Fractional contents of the secondary structure of BSA ( fα, fβ, fturn and frandom) were calculated with and without amino acid Schiff base complexes utilizing circular dichroism spectroscopy. Our results clarified that amino acid Schiff base complexes could bind to BSA and be effectively transported and eliminated in the body, which could be a useful guideline for further drug

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

    SciTech Connect

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

    1988-11-16

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

  7. Synthesis, characterization and biological activity of some unsymmetrical Schiff base transition metal complexes.

    PubMed

    Esmadi, Fatima T; Khabour, Omar F; Abbas, Khamis; Mohammad, Abdel Elah; Obeidat, Ra'ad T; Mfady, Doa'a

    2016-01-01

    In this study, several unsymmetrical Schiff bases and their cobalt and manganese complexes have been synthesized and characterized. The unsymmetrical Schiff bases were prepared from reaction of o-phenylendiamine derivatives with 1-hydroxy-2-acetonaphthone and then the product was reacted with the following aldehydes: salicyaldehyde, 2-hydroxynaphthaldehyde, 2-pyridinecarboxaldehyde and 2-qinolinecarboxaldehyde to produce the desired tetradentate unsymmetrical Schiff base ligands H2SL, H2NL, HPYL and HQN, respectively. Reaction of these ligands with cobalt and manganese salts produced complexes of the general formula [M(SL)], [(NL)], [M(PYL)] and [M(QL)]. All the complexes were characterized by elemental analysis, infrared spectroscopy, UV-visible spectroscopy, electrical conductivity and magnetic susceptibility measurements. The prepared complexes were examined for their anti-bacterial activity using gram-positive and gram-negative pathogens. The following complexes showed strong antibacterial activity against Staphylococcus aureus: MnSL1, MnSL2 and MnSL3. The genotoxic activity of four complexes, which are MnNL1, MnSL1, CoNL1 and CoSL1, were examined using 8-hydroxy-2-deoxy guanosine (8-OHdG) assay in cultured human blood lymphocytes. All examined complexes were found to be genotoxic at examined concentrations (0.1-100 µg/mL), but with variable magnitudes (p < 0.05). The levels of 8-OHdG induced by MnNL1 and MnSL1 were significantly higher than that induced by CoNL1 and CoSL1 ones. In general, the order of mutagenicity of the compounds is MnSL1 > MnNL1 > CoSL1 > CoNL1. In conclusion, some of the prepared complexes showed some biological activities that might be of interest for future research.

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

    SciTech Connect

    Lekshmy, R. K. E-mail: tharapradeepkumar@yahoo.com; Thara, G. S. E-mail: tharapradeepkumar@yahoo.com

    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.

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

    PubMed

    Shekaari, Hemayat; Kazempour, Amir; Khoshalhan, Maryam

    2015-01-21

    Schiff bases and their metal complexes in the mixtures of ionic liquid (IL) + organic solvent have shown great potential in attractive oxidation catalytic processes. The efficiency of such a process is strongly dependent on the various molecular interactions occurring between components. Thermodynamic properties of these systems can provide valuable information about structural interactions. Therefore, in this work, the interactions of the IL 1-hexyl-3-methylimidazolium chloride ([HMIm]Cl) with Schiff bases in organic solvents were studied through the measurements of density, viscosity, and electrical conductivity. The effect of solvent on the interactions was examined by the solutions of IL + BPIC Schiff base + solvent (C2H6O-C3H8O-C4H10O). Moreover, the influence of Schiff base ligand and Schiff base complex structures was probed by the solutions of IL + DMA + ligand (salcn/salpr/salen) and IL + DMA + complex (VO(3-OMe-salen)/VO(salophen)/VO(salen)), respectively. Using the experimental data, some important thermodynamic properties, such as standard partial molar volume (V(0)(φ,IL)), experimental slope (Sv), viscosity B-coefficient, solvation number (B/V(0)(φ,IL) and limiting molar conductivity (Λ0) were calculated and discussed in terms of solute-solvent (IL-DMF/alcohol) and solute-cosolute (IL-Schiff base) interactions.

  10. Synthesis and spectroscopic studies of binuclear metal complexes of a tetradentate N 2O 2 Schiff base ligand derived from 4,6-diacetylresorcinol and benzylamine

    NASA Astrophysics Data System (ADS)

    Shebl, Magdy

    2008-09-01

    A tetradentate N 2O 2 donor Schiff base ligand, H 2L, was synthesized by the condensation of 4,6-diacetylresorcinol with benzylamine. The structure of the ligand was elucidated by elemental analyses, IR, 1H NMR, electronic and mass spectra. Reaction of the Schiff base ligand with nickel(II), cobalt(II), iron(III), cerium(III), vanadyl(IV) and uranyl(VI) ions in 1:2 molar ratio afforded binuclear metal complexes. Also, reaction of the ligand with several copper(II) salts, including Cl -, NO 3-, AcO -, ClO 4- and SO 42- afforded different metal complexes that reflect the non-coordinating or weakly coordinating power of the ClO 4- anion as compared to the strongly coordinating power of SO 42- and Cl - anions. Characterization and structure elucidation of the prepared complexes were achieved by elemental and thermal analyses, IR, 1H NMR, electronic, mass and ESR spectra as well as magnetic susceptibility measurements. The metal complexes exhibited different geometrical arrangements such as square planar, octahedral, square pyramidal and pentagonal bipyramidal arrangements. The variety in the geometrical arrangements depends on the nature of both the anion and the metal ion.

  11. Photogalvanic and photovoltaic effects in systems based on metal complexes of Schiff bases

    NASA Astrophysics Data System (ADS)

    Smirnova, E. A.; Besedina, M. A.; Karushev, M. P.; Vasil'ev, V. V.; Timonov, A. M.

    2016-05-01

    The nature of the processes that occur when electrodes modified with complexes [M(Schiff)] (M = Ni, Pd, Pt; Schiff denotes four-dentate Schiff base ligands) are irradiated with visible light for the potential use of these electrodes in photoelectrochemical energy conversion devices is considered. The factors responsible for shifts in the electrode potential upon photoexcitation, i.e., the nature of the metal site, the nature of the substituents in the sensitizer, and the oxygen concentration are discussed. Tentative mechanisms of the photovoltaic effects observed for conventional and semiconductor electrodes modified with [M(Schiff)] complexes are determined.

  12. New sandwich-type lanthanide complexes based on closed-macrocyclic Schiff base and phthalocyanine molecules.

    PubMed

    Gao, Feng; Feng, Xiaowan; Yang, Liu; Chen, Xiaoyu

    2016-04-25

    Two new sandwich-type lanthanide complexes with the general formula [(Pc)2Ln3(L)(OAc)(OCH3)2] (Ln(3+) = Dy(3+) () and Er(3+) ()) were successfully synthesized and structurally characterized based on closed-macrocyclic Schiff base and phthalocyanine molecules. The magnetic properties and structure-property relationship in this multi-decker system were investigated. Interestingly, the corresponding dysprosium complex shows typical single-molecule magnetic behavior with ferromagnetic dipole-dipole interactions and the slow relaxation of magnetization. PMID:27044594

  13. A study of in vitro antibacterial activity of lanthanides complexes with a tetradentate Schiff base ligand

    PubMed Central

    Al Momani, Waleed Mahmoud; Taha, Ziyad Ahmed; Ajlouni, Abdulaziz Mahmoud; Shaqra, Qasem Mohammad Abu; Al Zouby, Muaz

    2013-01-01

    Objective To establish the antibacterial activity of lanthanides complexes with a tetradentate Schiff base ligand L. Methods (N, N′-bis (1-naphthaldimine)-o-phenylenediamine) was prepared from the condensation of 2-hydroxy-1-naphthaldehyde with o-phenylenediamine in a molar ratio of 2:1. The antimicrobial activity of the resultant Ln (III) complexes was investigated using agar well diffusion and micro-broth dilution techniques; the latter was used to establish the minimum inhibitory concentrations for each compound investigated. Results Most of Ln (III) complexes were found to exhibit antibacterial activities against a number of pathogenic bacteria with MICs ranging between 1.95-250.00 µg/mL. Staphylococcus aureus was the most susceptible bacterial species to [LaL(NO3)2(H2O)](NO3) complex while Shigella dysenteriae and Escherichia coli required a relatively higher MIC (250 µg/mL). The complexes La (III) and Pr (III) were effective inhibitors against Staphylococcus aureus, whereas Sm (III) complex was effective against Serratia marcescens. On the other hand, Gd (III), La (III) and Nd (III) were found to be more potent inhibitors against Pseudomonas aeruginosa than two of commonly used antibiotics. The remaining Ln (III) complexes showed no remarkable activity as compared to the two standard drugs used. Conclusions Tetradentate Schiff base ligand L and its complexes could be a potential antibacterial compounds after further investigation. PMID:23646299

  14. Zinc (II) complex with a cationic Schiff base ligand: Synthesis, characterization, and biological studies

    NASA Astrophysics Data System (ADS)

    Lee, Sze Koon; Tan, Kong Wai; Ng, Seik Weng; Ooi, Kah Kooi; Ang, Kok Pian; Abdah, Md Akim

    2014-03-01

    A cationic Schiff base ligand, TSB (L) and its Zn (II) complex (1) were synthesized and characterized by using CHN, 1H-NMR, FT-IR, UV, LC-MS, and X-ray methods. Their ability to inhibit topoisomerase I, DNA cleavage activities, and cytotoxicity were studied. X-ray diffraction study shows that the mononuclear complex 1 is four coordinated with distorted tetrahedral geometry. The singly deprotonated Schiff base ligand L acts as a bidentate ON-donor ligand. Complexation of L increases the inhibitory strength on topoisomerase I activity. Complex 1 could fully inhibit topoisomerase I activity at 250 μM, while L did not show any inhibitory effect on topoisomerase I activity. In addition, L and complex 1 could cleave pBR322 DNA in a concentration and time dependent profile. Surprisingly, L has better DNA cleavage activity than complex 1. The cleavage of DNA by complex 1 is altered in the presence of hydrogen peroxide. Furthermore, L and complex 1 are mildly cytotoxic towards human ovarian cancer A2780 and hepatocellular carcinoma HepG2.

  15. 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.

  16. Ruthenium(II)-Schiff base complexes derived from substituted salicylaldimines and triphenylphosphine

    SciTech Connect

    Armando, M.B.; Lena, R.R.; Rafael, M.E.; Federico, D.R.P.J.

    1993-12-31

    Synthesis and characterization of a series of octahedral ruthenium(II) Schiff base complexes obtained from the interaction of RuCl{sub 2}(PPh{sub 3}){sub 3} with N,N{prime}-ethylene-bis-(5-R-salicylideneimine) are presented. Redox properties and the stability towards oxidation of [Ru(II)(5R-sal{sub 2}en)(PPh{sub 3}){sub 2}] complexes, (R = H-(1), Cl-(2), Br-(3), CH{sub 3}O-(4), NO{sub 2}-(5)) were related to the electron-withdrawing or releasing ability of the substituent in the phenyl ring of the Schiff base. Results show that electron-withdrawing substituents stabilize Ru(II) complexes, while electron-donating groups favour oxidation to Ru(III). Changes in E{sub 1/2} for the complexes, due to remote substituent effects, could be related to changes in basicity of the phenolic oxygen. This variation has more influence on E{sub 1/2} than changes in basicity of the phosphorus in the phosphine ligand. 32 refs., 7 figs., 3 tabs.

  17. 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.

  18. The Zinc-Schiff Base-Novicidin Complex as a Potential Prostate Cancer Therapy

    PubMed Central

    Milosavljevic, Vedran; Haddad, Yazan; Merlos Rodrigo, Miguel Angel; Moulick, Amitava; Polanska, Hana; Hynek, David; Heger, Zbynek; Kopel, Pavel; Adam, Vojtech

    2016-01-01

    Prostate cancer cells control energy metabolism by chelating intracellular zinc. Thus, zinc delivery has been a popular therapeutic approach for prostate cancer. Here, we propose the use of the membrane-penetrating peptide Novicidin connected to zinc-Schiff base as a carrier vehicle for the delivery of zinc to prostate cells. Mass spectrometry, electrochemistry and spectrophotometry confirmed the formation/stability of this complex and provided insight regarding the availability of zinc for complex interactions. This delivery system showed minor toxicity in normal PNT1A cells and high potency towards PC3 tumor cells. The complex preferentially penetrated PC3 tumor cells in contrast to confinement to the membranes of PNT1A. Furthermore, zinc uptake was confirmed in both cell lines. Molecular analysis was used to confirm the activation of zinc stress (e.g., ZnT-1) and apoptosis (e.g., CASP-1). Our results strongly suggest that the zinc-Schiff base-Novicidin complex has great potential as a novel anticancer drug. PMID:27727290

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

    PubMed

    Hanif, Muhammad; Chohan, Zahid H

    2013-03-01

    A new series of three biologically active triazole derived Schiff base ligands L(1)-L(3) 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. PMID:23277183

  20. 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.

  1. A planar Schiff base platinum(II) complex: crystal structure, cytotoxicity and interaction with DNA.

    PubMed

    Peng, Yan; Zhong, Hui; Chen, Zhen-Feng; Liu, Yan-Cheng; Zhang, Guo-Hai; Qin, Qi-Pin; Liang, Hong

    2014-01-01

    A new platinum(II) complex of salphen derivative, namely Schiff base ligand that derived from o-phenylenediamine and 5-chlorosalicylaldehyde was synthesized. The complex possessed a planar mononuclear structure. The in vitro cytotoxicities of the complex were evaluated by microculture tetrozolium (MTT) assay against seven human tumor cell lines with the IC50 values of ca. 11.61 µM. Cell cycle analysis indicated that the complex induced apoptosis and G1-phase arrest in A549 cells. The results of colony formation assay showed that the complex could suppress the proliferation and viability of A549 cells. The binding of the complex to potential target DNA were investigated by fluorescence spectroscopy, viscosity measurements, fluorescence polarization and agarose gel electrophoresis. The results suggest that the most probable binding mode of the complex is intercalation. PMID:24583776

  2. 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.

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

    PubMed

    Mohammadi, Khosro; Niad, Mahmood; Jafari, Tahereh

    2014-03-25

    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 (H3L(1)), 3,4-bis((E)-2-hydroxy-3-methoxybenzylideneamino)benzoic acid (H3L(2)) and 3,4-bis((E)-5-bromo-2-hydroxybenzylideneamino)benzoic acid (H3L(4)). Additionally, a tetradentate Schiff base ligand 3,4-bis((E)-2-hydroxybenzylideneamino)benzoic acid (H3L(3)) 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, (1)H 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 0.1M (NaClO4), at 25 °C in dimethylformamide (DMF) as a solvent.

  4. Synthesis, spectral, antimicrobial and antitumor assessment of Schiff base derived from 2-aminobenzothiazole and its transition metal complexes

    NASA Astrophysics Data System (ADS)

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

    2011-09-01

    N-(thiophen-2-ylmethylene)benzo[ d]thiazol-2-amine Schiff base (L) derived from 2-aminobenzothiazole and 2-thiophenecarboxaldehyde was synthesized and characterized using elemental analysis, IR, mass spectra, 1H NMR and UV-vis spectra. Its complexes with Cu(II), Fe(III), Ni(II) and Zn(II) were prepared and isolated as solid products and characterized by elemental and thermal analyses, spectral techniques as well as magnetic susceptibility. The IR spectra showed that the Schiff base under investigation behaves as bidentate ligand. The UV-vis spectra and magnetic moment data suggested octahedral geometry around Cu(II) and Fe(III) and tetrahedral geometry around Ni(II) and Zn(II). In view of the biological activity of the Schiff base and its complexes, it has been observed that the antimicrobial activity of the Schiff base increased on complexation with the metal ion. In vitro antitumor activity assayed against five human tumor cell lines furnished the significant toxicities of the Schiff base and its complexes.

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

    NASA Astrophysics Data System (ADS)

    Shoukry, Azza A.; Shoukry, Mohamed M.

    2008-08-01

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

  6. In vitro antibacterial, antifungal and cytotoxic activities of some triazole Schiff bases and their oxovanadium(IV) complexes.

    PubMed

    Sumrra, Sajjad H; Chohan, Zahid H

    2013-12-01

    The condensation reaction of 3,5-diamino-1,2,4-triazole with methoxy-, chloro-, bromo-, iodo- and nitro-substituted 2-hydroxybenzaldehydes formed triazole Schiff bases (L(1))-(L(6)). The synthesized ligands have been characterized through physical, spectral and analytical data. Furthermore, the reaction of synthesized Schiff bases with the oxovanadium(IV) sulphate in (1:2) (metal:ligand) molar ratio afforded the oxovanadium(IV) complexes (1)-(6). All the complexes were non-electrolytic and showed a square-pyramidal geometry. The synthesized compounds have been screened for in-vitro antibacterial, antifungal and brine shrimp bioassay. The bioactivity data showed the complexes to be more active than the original Schiff bases.

  7. 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 (ΛM). 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.

  8. Synthesis and characterization of taurine Schiff base derivatives and their Cu(II) complexes: crystal and molecular structure of 5-NO/sub 2/ salicylaldimine ethylene sulfonic acid complex of Cu(II)

    SciTech Connect

    Perez-Cesar, M.C.; Soriano-Garcia, M.; Toscano, R.A.; Gomez-Lara, J.

    1986-04-01

    Spectroscopic analysis of eight copper(II) complexes of Schiff bases derived from taurine and eight different salicylaldehydes and naphthaldehydes are reported. X-ray structural analysis of the copper(II) complex of the 5-NO/sub 2/-salicylaldehyde imine of taurine (5-NO/sub 2/-salicylaldimine ethylene sulfonic acid) as the tetra n-butylammonium salt (Cu(C/sub 9/H/sub 8/N/sub 2/O/sub 6/S)/sub 2/)/sup 2 -/2((C/sub 4/H/sub 9/)/sub 4/N)/sup +/ (CUTAUTBA) has been carried out. The space group is P anti 1, with a = 8.761(4), b = 10.410(3), c = 16.528(4) A, ..cap alpha.. = 77.85(3), ..beta.. = 86.53(4), ..gamma.. = 79.15(3)/sup 0/, and Z = 1. The structure was solved by the heavy-atom method and refined by least-squares techniques to an R factor of 0.068 for 2807 observed reflections. The CUTAU cation is centrosymmetric, with the Cu atom sitting on a crystallographic center of symmetry. The copper atom has a square-planar environment, coordinated by the potentially tridentate Schiff base only through the imino nitrogen and the phenolate oxygen with the deprotonated sulfonic group directed away from the coordination sphere of the Cu(II).

  9. Spectroscopic and density functional theory investigation of novel Schiff base complexes.

    PubMed

    Hassan, Walid M I; Zayed, Ehab M; Elkholy, Asmaa K; Moustafa, H; Mohamed, Gehad G

    2013-02-15

    Novel Schiff base (H(2)L, 1,2-bis[(2-(2-mercaptophenylimino)methyl)phenoxy] ethane) derived from condensation of bisaldehyde and 2-aminothiophenol was prepared in a molar ratio 1:2. The ligand and its metal complexes are fully characterized with analytical and spectroscopic techniques. The metal complexes with Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II) and Th(IV) have been prepared and characterized by elemental analyses, IR and (1)H-NMR spectroscopy, thermal and magnetic measurements. The results suggested that the Schiff base is a bivalent anion with hexadentate OONNSS donors derived from the etheric oxygen (O, O'), azomethine nitrogen (N, N') and thiophenolic sulphur (S, S'). The formulae of the complexes were found to be [ML]·xH(2)O (M=Mn(II) (x=0), Co(II) (x=1), Ni(II), (x=1), Cu(II) (x=2) and Zn(II) (x=0)) and [ML]·nCl (M=Cr(III) (n=1), Fe(III) (n=1) and Th(IV) (n=2)). The thermogravimetric analysis of the complexes shows metal oxide remaining as the final product at 700-1000 °C. Density functional theory at the B3LYP/6-31G(*) level of theory was used to investigate molecular geometry, Mulliken atomic charges and energetics. The synclinal-conformer was found to be responsible for complex formation. The calculation showed that ligand has weak field. Structural deformation and the dihedral angles rotation during complexation were investigated. The binding energy of each complex was calculated. The calculated results are in good agreement with experimental data. PMID:23266605

  10. 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; Kučeráková, 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).

  11. Efficient water oxidation catalyzed by mononuclear ruthenium(II) complexes incorporating Schiff base ligands.

    PubMed

    Li, Ting-Ting; Chen, Yong; Li, Fu-Min; Zhao, Wei-Liang; Wang, Chuan-Jun; Lv, Xiao-Jun; Xu, Quan-Qing; Fu, Wen-Fu

    2014-06-23

    Four new charge-neutral ruthenium(II) complexes containing dianionic Schiff base and isoquinoline or 4-picoline ligands were synthesized and characterized by NMR and ESI-MS spectroscopies, elemental analysis, and X-ray diffraction. The complexes exhibited excellent chemical water oxidation activity and high stability under acidic conditions (pH 1.0) using (NH4)2Ce(NO3)6 as a sacrificial electron acceptor. The high catalytic activities of these complexes for water oxidation were sustained for more than 10 h at low concentrations. High turnover numbers of up to 3200 were achieved. A water nucleophilic attack mechanism was proposed. A Ru(V)=O intermediate was detected during the catalytic cycle by high-resolution mass spectrometry.

  12. Antibacterial activity of Pd(II) complexes with salicylaldehyde-amino acids Schiff bases ligands.

    PubMed

    Rîmbu, Cristina; Danac, Ramona; Pui, Aurel

    2014-01-01

    Palladium(II) complexes with Schiff bases ligands derived from salicylaldehyde and amino acids (Ala, Gly, Met, Ser, Val) have been synthesized and characterized by Fourier transform (FT)-IR, UV-Vis and (1)H-NMR spectroscopy. The electrospray mass spectrometry (ES-MS) spectrometry confirms the formation of palladium(II) complexes in 1/2 (M/L) molar ratio. All the Pd(II) complexes 1, [Pd(SalAla)2]Cl2; 2, [Pd(SalGly)2]Cl2; 3, [Pd(SalMet)2]Cl2; 4, [Pd(SalSer)2]Cl2; 5, [Pd(SalVal)2]Cl2; have shown antibacterial activity against Gram-positive bacteria Staphylococcus aureus and Gram-negative bacteria Escherichia coli.

  13. 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.

  14. Tuning of spin crossover behaviour in iron(III) complexes involving pentadentate Schiff bases and pseudohalides.

    PubMed

    Nemec, Ivan; Herchel, Radovan; Boča, Roman; Trávníček, Zdeněk; Svoboda, Ingrid; Fuess, Hartmut; Linert, Wolfgang

    2011-10-21

    Investigations on a series of eight novel mononuclear iron(III) Schiff base complexes with the general formula [Fe(L(5))(L(1))]·S (where H(2)L(5) = pentadentate Schiff-base ligand, L(1) = a pseudohalido ligand, and S is a solvent molecule) are reported. Several different aromatic 2-hydroxyaldehyde derivatives were used in combination with a non-symmetrical triamine 1,6-diamino-4-azahexane to synthesize the H(2)L(5) Schiff base ligands. The consecutive reaction with iron(III) chloride resulted in the preparation of the [Fe(L(5))Cl] precursor complexes which were left to react with a wide range of the L(1) pseudohalido ligands. The low-spin compounds were prepared using the cyanido ligand: [Fe(3m-salpet)(CN)]·CH(3)OH (1a), [Fe(3e-salpet)(CN)]·H(2)O (1b), while the high-spin compounds were obtained by the reaction of the pseudohalido (other than cyanido) ligands with the [Fe(L(5))Cl] complex arising from salicylaldehyde derivatives: [Fe(3Bu5Me-salpet)(NCS)] (2a), [Fe(3m-salpet)(NCO)]·CH(3)OH (2b) and [Fe(3m-salpet)(N(3))] (2c). The compounds exhibiting spin-crossover phenomena were prepared only when L(5) arose from 2-hydroxy-1-naphthaldehyde (H(2)L(5) = H(2)napet): [Fe(napet)(NCS)]·CH(3)CN (3a, T(1/2) = 151 K), [Fe(napet)(NCSe)]·CH(3)CN (3b, T(1/2) = 170 K), [Fe(napet)(NCO)] (3c, T(1/2) = 155 K) and [Fe(napet)(N(3))], which, moreover, exhibits thermal hysteresis (3d, T(1/2)↑ = 122 K, T(1/2)↓ = 117 K). These compounds are the first examples of octahedral iron(III) spin-crossover compounds with the coordinated pseudohalides. We report the structure and magnetic properties of these complexes. The magnetic data of all the compounds were analysed using the spin Hamiltonian formalism including the ZFS term and in the case of spin-crossover, the Ising-like model was also applied. PMID:21904754

  15. Towards dipyrrins: oxidation and metalation of acyclic and macrocyclic Schiff-base dipyrromethanes.

    PubMed

    Pankhurst, James R; Cadenbach, Thomas; Betz, Daniel; Finn, Colin; Love, Jason B

    2015-02-01

    Oxidation of acyclic Schiff-base dipyrromethanes cleanly results in dipyrrins, whereas the macrocyclic 'Pacman' analogues either decompose or form new dinuclear copper(ii) complexes that are inert to ligand oxidation; the unhindered hydrogen substituent at the meso-carbon allows new structural motifs to form.

  16. Schiff base triphenylphosphine palladium (II) complexes: Synthesis, structural elucidation, electrochemical and biological evaluation

    NASA Astrophysics Data System (ADS)

    Shabbir, Muhammad; Akhter, Zareen; Ahmad, Iqbal; Ahmed, Safeer; Shafiq, Maryam; Mirza, Bushra; McKee, Vickie; Munawar, Khurram Shahzad; Ashraf, Ahmad Raza

    2016-08-01

    The complexes N-(2-oxidophenyl)salicylideneiminatotriphenylphosphine palladium(II) (1) and N-(2-sulfidophenyl)salicylideneiminato triphenylphosphine palladium(II) (2) of tridentate Schiff bases derived from salicylaldehyde and an amino- or thiophenol, have been synthesized and characterized by various spectroscopic, analytical and electro-analytical techniques. X-ray single crystal analysis of complex 1 has revealed its square planar geometry. The thermal analysis has shown the absence of coordinated water and final degradation product is PdO. The alkaline phosphatase studies have indicated that enzymatic activity is concentration dependent which is inversely proportional to the concentration of the compounds. The biological assays (brine shrimp cytotoxicity, DPPH) have reflected their biologically active and mild antioxidant nature. However, results of DNA protection assay have shown that they possess moderate protective activity against hydroxyl free radicals (rad OH). The voltammetric studies ascertain two-electron reduction of the compounds through purely diffusion controlled process and reveal intercalative mode of drug DNA interactions.

  17. Synthesis, Characterization, Anticancer, and Antioxidant Studies of Ru(III) Complexes of Monobasic Tridentate Schiff Bases

    PubMed Central

    Ejidike, Ikechukwu P.

    2016-01-01

    Mononuclear Ru(III) complexes of the type [Ru(LL)Cl2(H2O)] (LL = monobasic tridentate Schiff base anion: (1Z)-N′-(2-{(E)-[1-(2,4-dihydroxyphenyl)ethylidene]amino}ethyl)-N-phenylethanimidamide [DAE], 4-[(1E)-N-{2-[(Z)-(4-hydroxy-3-methoxybenzylidene)amino]ethyl}ethanimidoyl]benzene-1,3-diol [HME], 4-[(1E)-N-{2-[(Z)-(3,4-dimethoxybenzylidene)amino]ethyl}ethanimidoyl]benzene-1,3-diol [MBE], and N-(2-{(E)-[1-(2,4-dihydroxyphenyl)ethylidene]amino}ethyl)benzenecarboximidoyl chloride [DEE]) were synthesized and characterized using the microanalytical, conductivity measurements, electronic spectra, and FTIR spectroscopy. IR spectral studies confirmed that the ligands act as tridentate chelate coordinating the metal ion through the azomethine nitrogen and phenolic oxygen atom. An octahedral geometry has been proposed for all Ru(III)-Schiff base complexes. In vitro anticancer studies of the synthesized complexes against renal cancer cells (TK-10), melanoma cancer cells (UACC-62), and breast cancer cells (MCF-7) was investigated using the Sulforhodamine B assay. [Ru(DAE)Cl2(H2O)] showed the highest activity with IC50 valves of 3.57 ± 1.09, 6.44 ± 0.38, and 9.06 ± 1.18 μM against MCF-7, UACC-62, and TK-10, respectively, order of activity being TK-10 < UACC-62 < MCF-7. The antioxidant activity by DPPH and ABTS inhibition assay was also examined. Scavenging ability of the complexes on DPPH radical can be ranked in the following order: [Ru(DEE)Cl2(H2O)] > [Ru(HME)Cl2(H2O)] > [Ru(DAE)Cl2(H2O)] > [Ru(MBE)Cl2(H2O)]. PMID:27597814

  18. Synthesis, Characterization, Anticancer, and Antioxidant Studies of Ru(III) Complexes of Monobasic Tridentate Schiff Bases

    PubMed Central

    Ejidike, Ikechukwu P.

    2016-01-01

    Mononuclear Ru(III) complexes of the type [Ru(LL)Cl2(H2O)] (LL = monobasic tridentate Schiff base anion: (1Z)-N′-(2-{(E)-[1-(2,4-dihydroxyphenyl)ethylidene]amino}ethyl)-N-phenylethanimidamide [DAE], 4-[(1E)-N-{2-[(Z)-(4-hydroxy-3-methoxybenzylidene)amino]ethyl}ethanimidoyl]benzene-1,3-diol [HME], 4-[(1E)-N-{2-[(Z)-(3,4-dimethoxybenzylidene)amino]ethyl}ethanimidoyl]benzene-1,3-diol [MBE], and N-(2-{(E)-[1-(2,4-dihydroxyphenyl)ethylidene]amino}ethyl)benzenecarboximidoyl chloride [DEE]) were synthesized and characterized using the microanalytical, conductivity measurements, electronic spectra, and FTIR spectroscopy. IR spectral studies confirmed that the ligands act as tridentate chelate coordinating the metal ion through the azomethine nitrogen and phenolic oxygen atom. An octahedral geometry has been proposed for all Ru(III)-Schiff base complexes. In vitro anticancer studies of the synthesized complexes against renal cancer cells (TK-10), melanoma cancer cells (UACC-62), and breast cancer cells (MCF-7) was investigated using the Sulforhodamine B assay. [Ru(DAE)Cl2(H2O)] showed the highest activity with IC50 valves of 3.57 ± 1.09, 6.44 ± 0.38, and 9.06 ± 1.18 μM against MCF-7, UACC-62, and TK-10, respectively, order of activity being TK-10 < UACC-62 < MCF-7. The antioxidant activity by DPPH and ABTS inhibition assay was also examined. Scavenging ability of the complexes on DPPH radical can be ranked in the following order: [Ru(DEE)Cl2(H2O)] > [Ru(HME)Cl2(H2O)] > [Ru(DAE)Cl2(H2O)] > [Ru(MBE)Cl2(H2O)].

  19. Synthesis, Characterization, Anticancer, and Antioxidant Studies of Ru(III) Complexes of Monobasic Tridentate Schiff Bases.

    PubMed

    Ejidike, Ikechukwu P; Ajibade, Peter A

    2016-01-01

    Mononuclear Ru(III) complexes of the type [Ru(LL)Cl2(H2O)] (LL = monobasic tridentate Schiff base anion: (1Z)-N'-(2-{(E)-[1-(2,4-dihydroxyphenyl)ethylidene]amino}ethyl)-N-phenylethanimidamide [DAE], 4-[(1E)-N-{2-[(Z)-(4-hydroxy-3-methoxybenzylidene)amino]ethyl}ethanimidoyl]benzene-1,3-diol [HME], 4-[(1E)-N-{2-[(Z)-(3,4-dimethoxybenzylidene)amino]ethyl}ethanimidoyl]benzene-1,3-diol [MBE], and N-(2-{(E)-[1-(2,4-dihydroxyphenyl)ethylidene]amino}ethyl)benzenecarboximidoyl chloride [DEE]) were synthesized and characterized using the microanalytical, conductivity measurements, electronic spectra, and FTIR spectroscopy. IR spectral studies confirmed that the ligands act as tridentate chelate coordinating the metal ion through the azomethine nitrogen and phenolic oxygen atom. An octahedral geometry has been proposed for all Ru(III)-Schiff base complexes. In vitro anticancer studies of the synthesized complexes against renal cancer cells (TK-10), melanoma cancer cells (UACC-62), and breast cancer cells (MCF-7) was investigated using the Sulforhodamine B assay. [Ru(DAE)Cl2(H2O)] showed the highest activity with IC50 valves of 3.57 ± 1.09, 6.44 ± 0.38, and 9.06 ± 1.18 μM against MCF-7, UACC-62, and TK-10, respectively, order of activity being TK-10 < UACC-62 < MCF-7. The antioxidant activity by DPPH and ABTS inhibition assay was also examined. Scavenging ability of the complexes on DPPH radical can be ranked in the following order: [Ru(DEE)Cl2(H2O)] > [Ru(HME)Cl2(H2O)] > [Ru(DAE)Cl2(H2O)] > [Ru(MBE)Cl2(H2O)]. PMID:27597814

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

    NASA Astrophysics Data System (ADS)

    Topacli, C.; Topacli, A.

    2003-06-01

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

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

    PubMed

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

    2014-03-25

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

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

    PubMed Central

    Abou-Hussein, Azza A.; Linert, Wolfgang

    2014-01-01

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

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

    NASA Astrophysics Data System (ADS)

    Abou-Hussein, Azza A.; Linert, Wolfgang

    2014-01-01

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

  4. 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.

  5. Synthesis, spectroscopic, antimicrobial, DNA binding and cleavage studies of some metal complexes involving symmetrical bidentate N, N donor Schiff base ligand

    NASA Astrophysics Data System (ADS)

    Arish, D.; Nair, M. Sivasankaran

    2011-11-01

    The Schiff base ligand, N, N'-bis-(4-isopropylbenzaldimine)-1,2-diaminoethane (L), obtained by the condensation of 4-isopropylbenzaldehyde and 1,2-diaminoethane, has been used to synthesize the complexes of the type [ML 2X 2] [M = Co(II), Ni(II) and Zn(II); X = Cl and OAc]. The newly synthesized ligand (L) and its complexes have been characterized on the basis of elemental analyses, mass, 1H and 13C-NMR, molar conductance, IR, UV-vis, magnetic moment, CV and thermal analyses, powder XRD and SEM. IR spectral data show that the ligand is coordinated to the metal ions in a bidentate manner. The geometrical structures of these complexes are found to be octahedral. Interestingly, reaction with Cu(II) ion with this ligand undergoes hydrolytic cleavage to form ethylenediamine copper(II) complex and the corresponding aldehyde. The antimicrobial results indicate that the chloro complexes exhibit more activity than the acetato complexes. The complexes bind to CT-DNA by intercalation modes. Novel chloroform soluble ZnL 2Cl 2 complex exhibits tremendous antimicrobial, DNA binding and cleaving properties.

  6. 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 ΔE*, ΔH*, ΔS* and ΔG* 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.

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

    PubMed Central

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

    2013-01-01

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

  8. 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.

  9. Modulation of Amyloid-β Aggregation by Histidine-coordinating Cobalt(III) Schiff Base Complexes

    PubMed Central

    Heffern, Marie C.; Velasco, Pauline T.; Matosziuk, Lauren M.; Coomes, Joseph L.; Karras, Constantine; Ratner, Mark A.; Klein, William B.; Eckermann, Amanda L.; Meade, Thomas J.

    2014-01-01

    Oligomers of the Aβ42 peptide are significant neurotoxins linked to Alzheimer’s Disease (AD). Histidine (His) residues present at the N-terminus of Aβ42 are believed to influence toxicity by either serving as metal-ion binding sites (that promote oligomerization and oxidative damage) or facilitating synaptic binding. Transition metal complexes that bind to these residues and modulate Aβ toxicity have emerged as therapeutic candidates. Cobalt(III) Schiff base complexes (Co(III)-sb) were evaluated for their ability to interact with Aβ peptides. HPLC-MS, NMR, fluorescence, and DFT studies demonstrated that Co(III)-sb complexes could interact with the His residues in a truncated Aβ16 peptide representing the Aβ42 N-terminus. Coordination of Co(III)-sb complexes altered the structure of Aβ42 peptides and promoted the formation of large soluble oligomers. Interestingly, this structural perturbation of Aβ correlated to reduced synaptic binding to hippocampal neurons. These results demonstrate the promise of Co(III)-sb complexes in anti-AD therapeutic approaches. PMID:24961930

  10. Novel nanohybrids of cobalt(III) Schiff base complexes and clay: Synthesis and structural determinations

    NASA Astrophysics Data System (ADS)

    Kianfar, Ali Hossein; Mahmood, Wan Ahmad Kamil; Dinari, Mohammad; Azarian, Mohammad Hossein; Khafri, Fatemeh Zare

    2014-06-01

    The [Co(Me2Salen)(PBu3)(OH2)]BF4 and [Co(Me2Salen)(PPh3)(Solv)]BF4, complexes were synthesized and characterized by FT-IR, UV-Vis, 1H NMR spectroscopy and elemental analysis techniques. The coordination geometry of [Co(Me2Salen)(PPh3)(H2O)]BF4 was determined by X-ray crystallography. It has been found that the complex is containing [Co(Me2Salen)(PPh3)(H2O)]BF4 and [Co(Me2Salen)(PPh3)(EtOH)]BF4 hexacoordinate species in the solid state. Cobalt atom exhibits a distorted octahedral geometry and the Me2Salen ligand has the N2O2 coordinated environment in the equatorial plane. The [Co(Me2Salen)(PPh3)(H2O)]BF4 complex shows a dimeric structure via hydrogen bonding between the phenolate oxygen and hydrogens of coordinated H2O molecule. These complexes were incorporated into Montmorillonite-K10 nanoclay. The modified clays were identified by FT-IR, XRD, EDX, TGA/DTA, SEM and TEM techniques. According to the XRD results of the new nanohybrid materials, the Schiff base complexes are intercalated in the interlayer spaces of the clay. SEM and TEM micrographs show that the resulting hybrid nanomaterials have layer structures. Also, TGA/DTG results show that the intercalation reaction was taken place successfully.

  11. 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*, ΔH*, ΔS* and ΔG* 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.

  12. 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.

    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.

  13. Tautomeric effect of hydrazone Schiff bases in tetranuclear Cu(II) complexes: magnetism and catalytic activity towards mild hydrocarboxylation of alkanes.

    PubMed

    Sutradhar, Manas; Kirillova, Marina V; Guedes da Silva, M Fátima C; Liu, Cai-Ming; Pombeiro, Armando J L

    2013-12-21

    Three new tetranuclear copper(II) complexes [Cu(HL(1))]4·4EtOH (1·4EtOH), [Cu(HL(2))]4 (2) and [Cu(H2L(3))]4(NO3)4·2H2O (3·2H2O) have been synthesized using three different hydrazone Schiff base ligands derived from the condensation of the aromatic acid hydrazides 2-hydroxybenzo-, 2-aminobenzo- or benzo-hydrazide, with 2,3-dihydroxybenzaldehyde. Complexes 1 and 3 have been characterized by single crystal X-ray diffraction analysis. The coordinating behaviour of the ligand depends on the nature of the ortho substituent present in the hydrazide moiety. The ligands bearing a strong electron donating group (by resonance) in the ortho position undergo complexation via enolization and deprotonation, whereas the absence of such an effect leads to complexation via the keto form, and two different types of tetranuclear Cu(II) clusters, viz. open-cubane and cubane, are obtained. Variable temperature magnetic susceptibility measurements of complexes 1 and 3 have been carried out to examine the nature of magnetic interaction between the Cu(II) centres. All the three complexes (1-3) act as good catalyst precursors towards mild hydrocarboxylation of linear and cyclic alkanes into carboxylic acids in water-acetonitrile medium. PMID:24068161

  14. Polymeric material prepared from Schiff base based on O-carboxymethyl chitosan and its Cu(II) and Pd(II) complexes

    NASA Astrophysics Data System (ADS)

    Baran, Talat; Menteş, Ayfer

    2016-07-01

    In this study, a new eco-friendly Schiff base based on O-carboxymethyl chitosan ([OCMCS-7a]) and its copper(II) and palladium(II) complexes were synthesized. Characterizations of [OCMCS-7a] and its metal complexes were conducted using FTIR, 1H NMR, 13C NMR, TG/DTG, XRD, SEM-EDAX, ICP, UV-VIS, GC-MS, elemental analysis, magnetic moment and molar conductivity measurements. The degree of substitution (DS) of [OCMCS-7a] was determined by elemental analysis to be 0.44. It was shown by the solubility test that [OCMCS-7a] was completely soluble in water. Surface images of chitosan, [OCMCS-7a] and its Cu(II) and Pd(II) complexes were investigated using the SEM-EDAX technique. Their thermal behaviors and crystallinities of the synthesized complexes were determined by TG/DTG and X-ray powder diffraction techniques, respectively. The metal contents of the obtained complexes were determined using an ICP-OES instrument. From the analyses, it was noted that the thermal stabilities and crystallinities of [OCMCS-7a] and its complexes decreased compared to chitosan. As a consequence of surface screening, it was also noted that the surface structure of the chitosan was smoother than that of the obtained compounds.

  15. 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.

  16. 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.

  17. 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

  18. 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

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

    PubMed

    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 ((1)H, (13)C, and (29)Si) 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.

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

    SciTech Connect

    Brown, L.S.; Varo, G.; Lanyi, J.K.

    1995-10-03

    During the L {r_arrow} 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 form D96 in the M {r_arrow} 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 {leftrightarrow} 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 pK{sub a} of the protonated Schiff base, and now D85 becomes protonated as in the wild type. We conclude from these results that the proton transfers to and from the Schiff base, and now D85 becomes protonated as in the wild type. We conclude form these results that the proton transfers to and from the Schiff base probably both occur after photoexcitation of D212N/R82Q, but the L {leftrightarrow} M and M {leftrightarrow} N equilibria are shifted away from M, and, untypically, D85 does not retain the proton it had gained. 72 refs., 11 figs., 1 tab.

  1. Synthesis and structures of transition metal pacman complexes of heteroditopic Schiff-base pyrrole macrocycles.

    PubMed

    Leeland, James W; Finn, Colin; Escuyer, Bérengère; Kawaguchi, Hiroyuki; Nichol, Gary S; Slawin, Alexandra M Z; Love, Jason B

    2012-12-01

    A series of polydentate dual-compartment, Schiff-base pyrrole macrocycles has been prepared through the straightforward Lewis acid catalysed [1 + 1] condensation reactions between ONO or O(5)-linked aryldiamines and dipyrromethane dialdehydes. These macrocycles display hydrogen-bond acceptor and donor properties and provide distinct N(4) and O(5)/ONO donor sets for metallation reactions, so forming alkali, alkaline earth, and transition metal complexes that were characterised spectroscopically and crystallographically. While the conformationally flexible O(5) donor set allows the formation of helical potassium salt structures, the transition metal complexes of all variants of these macrocycles invariably adopt wedged, Pacman-shaped structures in which the metal is bound in the pyrrole-imine N(4) donor set, so leaving the ONO/O(5) donor set pendant and apical. In some cases (V, Cr, and Co), this proximate combination of Lewis acid binding site and hydrogen bond acceptor facilitates the coordination of water within the molecular cleft; alternatively, direct interaction between the pendant arm and the metal is seen (e.g. Ti). Higher order [2 + 2] macrocycles were also prepared as minor, inseparable by-products of cyclisation, and Fe(2), Mn(2), and Co(2) complexes of these larger macrocycles were found to adopt binuclear helical structures by X-ray crystallography.

  2. Structural Determinants of p53-Independence in Anticancer Ruthenium-Arene Schiff-Base Complexes.

    PubMed

    Chow, Mun Juinn; Babak, Maria V; Wong, Daniel Yuan Qiang; Pastorin, Giorgia; Gaiddon, Christian; Ang, Wee Han

    2016-07-01

    p53 is a key tumor suppressor gene involved in key cellular processes and implicated in cancer therapy. However, it is inactivated in more than 50% of all cancers due to mutation or overexpression of its negative regulators. This leads to drug resistance and poor chemotherapeutic outcome as most clinical drugs act via a p53-dependent mechanism of action. An attractive strategy to circumvent this resistance would be to identify new anticancer drugs that act via p53-independent mode of action. In the present study, we identified 9 Ru (II)-Arene Schiff-base (RAS) complexes able to induce p53-independent cytotoxicity and discuss structural features that are required for their p53-independent activity. Increasing hydrophobicity led to an increase in cellular accumulation in cells with a corresponding increase in efficacy. We further showed that all nine complexes demonstrated p53-independent activity. This was despite significant differences in their physicochemical properties, suggesting that the iminoquinoline ligand, a common structural feature for all the complexes, is required for the p53-independent activity.

  3. Chemistry of technetium. Elaboration of the mechanism of action of skeletal imaging agents and development of technetium Schiff base complexes

    SciTech Connect

    Jurisson, S.S.

    1982-01-01

    Tc-99m skeletal imaging agents contain diphosphonate ligands coordinated to a technetium center. To investigate the chemistry of coordinated diphosphonates, complexes of the type ((en)/sub 2/Co(O/sub 2/P(OH)C(R)(R')P(OH)O/sub 2/)/sup n+/ have been synthesized and characterized. The affinities of these species for calcium ion in solution have been determined and found to be dependent on the substituents, R and R', of the diphosphonate moiety. The single crystal X-ray structural determination of ((en)/sub 2/Co(O/sub 2/P(OH)CH/sub 2/P(OH)O/sub 2/)ClO/sub 4/ x 2H/sub 2/O illustrates the configuration of a coordinated diphosphonate in the solid state and allows for the implication of possible binding modes of this species to the calcium ion in solution. A series of Tc(V) complexes containing tetradentate Schiff base ligands (derived from diamines and either acetylacetonates or salicylaldehyde) has been synthesized and characterized. An investigation of the reactivity of the Tc(V)-Schiff base complexes with phosphines led to the development of a series of Tc(III)-Schiff base complexes containing two coordinated phosphine ligands, i.e., tr-(Tc(Schiff base)(PRR')/sub 2/)PF/sub 6/. These complexes show intriguing redox behavior in that they exhibit both reversible Tc(III)/Tc(II) and Tc(III)/Tc(IV) couples. The substituents on the Schiff base and phosphine ligands have significant effects on the redox potentials of the technetium(III) center and on the MTLCT bands observed for these complexes. Those substituents which make the Schiff base and phosphine ligands better sigma donors make the Tc(III) more difficult to reduce to Tc(II) and easier to oxidize to Tc(IV). The relatonship between the energy of the MTLCT band and the E/sup 0/ values for these complexes is linear with slopes to unity, suggesting that the ligands contribute equally to these properties.

  4. 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 μg/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)ṡH2O complex was found to be most potent antimicrobial agent.

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

    PubMed

    Devi, Jai; Batra, Nisha

    2015-01-25

    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 μg/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. PMID:25129626

  6. 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 (π-π(∗)) fluorescence and can potentially serve as photoactive materials. Both the ligand and its complexes have been screened for antibacterial activities.

  7. Synthesis and spectral characterization of trinuclear, oxo-centered, carboxylate-bridged, mixed-valence iron complexes with Schiff bases.

    PubMed

    Singh, Atresh Kumar; Singh, Alok Kumar

    2012-10-01

    Some novel trinuclear, oxo-centered, carboxylate-bridged, mixed-valence iron complexes of the general formula [Fe(3)O(OOCR)(3)(SB)(3)L(3)] (where R=C(13)H(27), C(15)H(31) or C(17)H(35,) HSB=Schiff bases and L=Ethanol) have been synthesized by the stepwise substitutions of acetate ions from μ(3)-oxo-hexa(acetato)tri(aqua)iron(II)diiron(III), first with straight chain carboxylic acids and then with Schiff bases. The complexes were characterized by elemental analyses, molecular weight determinations and spectral (electronic, infrared, FAB mass, Mössbauer and powder XRD) studies. Molar conductance measurements indicated the complexes to be non-electrolytes in nitrobenzene. Bridging nature of carboxylate and Schiff base anions in the complexes was established by their infrared spectra. Mössbauer spectroscopic studies indicated two quadrupole-split doublets due to Fe(II) and Fe(III) ions at 80, 200 and 295K, confirming the complexes are mixed-valence species. This was also supported by the observed electronic spectra of the complexes. Magnetic susceptibility measurements displayed octahedral geometry around iron in mixed-valence state and a net antiferromagnetic exchange coupling via μ-oxo atom. Trinuclear nature of the complexes was confirmed by their molecular weight determination and FAB mass spectra. A plausible structure for these complexes has been established on the basis of spectral and magnetic moment data.

  8. Synthesis and spectral characterization of trinuclear, oxo-centered, carboxylate-bridged, mixed-valence iron complexes with Schiff bases

    NASA Astrophysics Data System (ADS)

    Singh, Atresh Kumar; Singh, Alok Kumar

    2012-10-01

    Some novel trinuclear, oxo-centered, carboxylate-bridged, mixed-valence iron complexes of the general formula [Fe3O(OOCR)3(SB)3L3] (where R = C13H27, C15H31 or C17H35, HSB = Schiff bases and L = Ethanol) have been synthesized by the stepwise substitutions of acetate ions from μ3-oxo-hexa(acetato)tri(aqua)iron(II)diiron(III), first with straight chain carboxylic acids and then with Schiff bases. The complexes were characterized by elemental analyses, molecular weight determinations and spectral (electronic, infrared, FAB mass, Mössbauer and powder XRD) studies. Molar conductance measurements indicated the complexes to be non-electrolytes in nitrobenzene. Bridging nature of carboxylate and Schiff base anions in the complexes was established by their infrared spectra. Mössbauer spectroscopic studies indicated two quadrupole-split doublets due to Fe(II) and Fe(III) ions at 80, 200 and 295 K, confirming the complexes are mixed-valence species. This was also supported by the observed electronic spectra of the complexes. Magnetic susceptibility measurements displayed octahedral geometry around iron in mixed-valence state and a net antiferromagnetic exchange coupling via μ-oxo atom. Trinuclear nature of the complexes was confirmed by their molecular weight determination and FAB mass spectra. A plausible structure for these complexes has been established on the basis of spectral and magnetic moment data.

  9. 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 (π-π∗) fluorescence and can potentially serve as photoactive materials. Both the ligand and its complexes have been screened for antibacterial activities.

  10. 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; Okumuş, 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 (ΛM). 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.

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

    SciTech Connect

    Mini, S. Sadasivan, V.; Meena, S. S. Bhatt, Pramod

    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}].

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

    NASA Astrophysics Data System (ADS)

    Mini, S.; Sadasivan, V.; Meena, S. S.; Bhatt, Pramod

    2014-10-01

    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 FeCl3˙2H2O 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(H2O)2] and [Fe(FAHP)Cl2(H2O)2].

  13. 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.

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

    PubMed

    Sayin, Koray; Kariper, Sultan Erkan; Sayin, Tuba Alagöz; Karakaş, 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

  15. Synthesis and spectroscopic characterization of cationic mononuclear oxovanadium(IV) complexes with tetradentate Schiff bases as ligands

    NASA Astrophysics Data System (ADS)

    Gangadharmath, Umesh B.; Revankar, Vidyanand K.; Mahale, Vinayak B.

    2002-10-01

    New tetradentate Schiff-base oxovanadium(IV) complexes [VOL']SO 4 (where L'=tetradentate ligands derived from 2,4-dihydroxy 5-acetyl acetophenone and substituted diamines) were prepared and characterized by physico-chemical techniques. All the complexes are monomeric in nature and a square-pyramidal geometry is proposed. Various ligand-field and molecular-orbital parameters have been calculated.

  16. Cobalt-Schiff base complex catalyzed oxidation of para-substituted phenolics. Preparation of benzoquinones

    SciTech Connect

    Bozell, J.J.; Hames, B.R.; Dimmel, D.R.

    1995-04-21

    Para-substituted phenolics, serving as models for lignin (a renewable source of carbon), are oxidized to the corresponding benzoquinone with oxygen in the presence of catalytic amounts of Co-Schiff base complexes. The reaction products observed depend on the structure of the catalyst. The 5-coordinate catalysts (pyridine)[bis(salicylidene)ethylenediamine]cobalt[(pyr)Co(salen)]and[bis(salicylideneamino)ethylamine]cobalt [Co(n-Me salpr)] convert syringyl alcohol (3,5-dimethoxy-4-hydroxybenzyl alcohol) to 2,6-dimethoxybenzoquinone in high yield. In contrast, syringaldehyde (3,5-dimethoxy-4-hydroxybenzaldehyde) is unreactive toward these catalysts. However, the 4-coordinate Co(salen) converts syringaldehyde to 2,6-dimethoxybenzoiquinone in 72% isolated yield. Phenols bearing a single methoxy group on the ring are unreactive toward any catalyst in MeOH. However, vanillyl alcohol (3-methoxy-4-hydroxybenzyl alcohol) is converted to 2-methoxybenzo-quinone with Co(N-Me salpr) and oxygen in 43% yield in CH{sub 2}Cl{sub 2} and 58% yield in CH{sub 2}Cl{sub 2} in the presence of 1% CuCl{sub 2}. The success of the oxidations appears to be related to the ease of removal of the phenolic hydrogen by the Co/O{sub 2} complex. Competitive deactivation of the catalyst occurs with substrates of lower reactivity. 84 tabs.

  17. 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

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

    PubMed

    Nemec, Ivan; Herchel, Radovan; Svoboda, Ingrid; Boča, Roman; Trávníček, Zdeněk

    2015-05-28

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

  19. Synthesis, structure and antidiabetic activity of chromium(III) complexes of metformin Schiff-bases

    NASA Astrophysics Data System (ADS)

    Mahmoud, M. A.; Zaitone, S. A.; Ammar, A. M.; Sallam, S. A.

    2016-03-01

    A series of Cr3+ complexes with Schiff-bases of metformin with each of salicylaldehyde (HL1); 2,3-dihydroxybenzaldehyde (H2L2); 2,4-dihydroxybenzaldehyde (H2L3); 2,5-dihydroxybenzaldehyde (H2L4); 3,4-dihydroxybenzaldehyde (H2L5) and 2-hydroxynaphthaldehyde (HL6) were synthesized by template reaction. The new compounds were characterized through elemental analysis, conductivity and magnetic moment measurements, IR, UV-Vis., NMR and mass spectroscopy. The complexes have octahedral structure with μ value of hexacoordinated chromium ion. TGA, DTG and DTA analysis confirm the proposed stereochemistry and a mechanism for thermal decomposition was proposed. Thermodynamic parameters are calculated for the second and third decomposition steps. [CrL4Cl(H2O)2].3H2O and [CrL5Cl(H2O)2].2½H2O were able to produce significant decreases in the blood glucose level.

  20. 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; Uruş, Serhan; Demirtaş, İbrahim; Elmastaş, 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.

  1. Exploring the distribution of copper-Schiff base complex covalently anchored onto the surface of mesoporous MCM 41 silica

    SciTech Connect

    Singh, Udayshankar G. . E-mail: usingh@engr.ucsb.edu; Williams, Ruth T. . E-mail: r.t.williams@open.ac.uk; Hallam, Keith R. . E-mail: k.r.hallam@bristol.ac.uk; Allen, Geoffrey C. . E-mail: g.c.allen@bristol.ac.uk

    2005-11-15

    A series of copper-Schiff base MCM 41 materials, synthesized by post-synthetic grafting, was studied by X-ray photoelectron spectroscopy (XPS) and nitrogen sorption (77 K) to explore distribution of the copper-Schiff base complex immobilized on the porous Si-MCM 41. Additional information on the physico-chemical properties of the functionalized materials was obtained by powder X-ray diffraction (XRD), atomic absorption spectroscopy (AAS), CHN microanalysis, FTIR spectroscopy, {sup 29}Si and {sup 13}C CP MAS NMR spectroscopy. The effect of copper-Schiff base complex loading and reaction times on the surface properties of Si-MCM 41 (surface area and pore parameters) in addition to its distribution within the Si-MCM 41 was explored by nitrogen sorption and XPS coupled with argon etching. Argon etching of a surface to a depth of 45 A confirmed that the copper-Schiff base complex was distributed both on the external surface (pore end) and within the pores of Si-MCM 41. The amount of complex located in the pores at this depth was about one-third of the amount detected on the external surface of MCM 41. Nitrogen sorption isotherms measured at 77 K confirmed the reduction in total pore volume and surface area was the result of pore narrowing of Si-MCM 41 following grafting of complex in the 8 h samples. A significant decrease in surface area and pore volume for the 20 h sample (longer reaction time), with the highest copper loading (0.65 mmol g{sup -1}), confirmed pore blocking in this material. The uneven distribution of the copper complex between the external and internal surface of Si-MCM 41 was attributed to the bulky nature of the complex, which restricted access to the pores.

  2. A one-dimensional azido-bridged manganese(III) complex with bidentate Schiff base: Crystal structure and magnetic properties

    SciTech Connect

    Li Wei; Li Zongwei; Li Licun Liao Daizheng; Jiang Zonghui

    2007-10-15

    The synthesis, structural characterization, and magnetic behavior of a novel one-dimensional azido-bridged manganese(III) complex of formula [Mn(L){sub 2}N{sub 3}] (1) is reported, where HL is the bidentate Schiff base obtained from the condensation of salicylaldehyde with 4-methoxy aniline. Complex 1 crystallizes in the monoclinic system, space group P2{sub 1}/n, with a=11.743(4) A, b=24.986(9) A, c=13.081(5) A, {beta}=95.387(7){sup o} and Z=2. The complex is of one-dimensional chain structure with single end-to-end azido bridges and the manganese(III) ion has an elongated octahedral geometry. Magnetic studies show that the weak antiferromagnetic interaction is mediated by the single end-to-end azido bridge with the exchange parameter J=-5.84 cm{sup -1}. - Graphical abstract: A novel azido-bridged manganese(III) complex with bidentate Schiff base ligands has been prepared and characterized structurally and magnetically. The complex is of one-dimensional chain structure with single end-to-end azido bridges in axial positions. Two bidentate Schiff base ligands coordinate in the equatorial mode. The magnetic measurements show that the complex exhibits weak antiferromagnetic interaction.

  3. Spectroscopic, thermal analysis and DFT computational studies of salen-type Schiff base complexes

    NASA Astrophysics Data System (ADS)

    Ebrahimi, Hossein Pasha; Hadi, Jabbar S.; Abdulnabi, Zuhair A.; Bolandnazar, Zeinab

    2014-01-01

    A new series of metal(II) complexes of Co(II), Ni(II), Cu(II), Zn(II), and Pb(II) have been synthesized from a salen-type Schiff base ligand derived from o-vanillin and 4-methyl-1,2-phenylenediamine and characterized by elemental analysis, spectral (IR, UV-Vis, 1H NMR, 13C NMR and EI-mass), molar conductance measurements and thermal analysis techniques. Coats-Redfern method has been utilized to calculate the kinetic and thermodynamic parameters of the metal complexes. The molecular geometry, Mulliken atomic charges of the studied compounds were investigated theoretically by performing density functional theory (DFT) to access reliable results to the experimental values. The theoretical 13C chemical shift results of the studied compounds have been calculated at the B3LYP, PBEPBE and PW91PW91 methods and standard 6-311+G(d,p) basis set starting from optimized geometry. The comparison of the results indicates that B3LYP/6-311+G(d,p) yields good agreement with the observed chemical shifts. The measured low molar conductance values in DMF indicate that the metal complexes are non-electrolytes. The spectral and thermal analysis reveals that all complexes have octahedral geometry except Cu(II) complex which can attain the square planner arrangement. The presence of lattice and coordinated water molecules are indicated by thermograms of the complexes. The thermogravimetric (TG/DTG) analyses confirm high stability for all complexes followed by thermal decomposition in different steps.

  4. 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.

  5. Synthesis, characterization and biological properties of thienyl derived triazole Schiff bases and their oxovanadium(IV) complexes.

    PubMed

    Chohan, Zahid H; Sumrra, Sajjad H

    2012-04-01

    A new series of biologically active thienyl derived triazole Schiff bases and their oxovanadium(IV) complexes have been synthesized and characterized on the basis of physical (m.p., magnetic susceptibility and conductivity), spectral (IR, ¹H and ¹³C NMR, electronic and mass spectrometry) and microanalytical data. All the Schiff base ligands and their oxovanadium(IV) complexes have been subjected to in vitro antibacterial activity against four Gram-negative (Escherichia coli, Shigella flexneri, Pseudomonas aeruginosa, Salmonella enterica serover typhi) and two Gram-positive (Staphylococcus aureus and Bacillus subtilis) bacterial strains and, for in vitro antifungal activity against Trichophyton longifucus, Candida albican, Aspergillus flavus, Microscopum canis, Fusarium solani and Candida glabrata. Brine shrimp bioassay was also carried out to check the cytotoxic nature of these compounds. PMID:21635212

  6. New asymmetric heptaaza Schiff base macrocyclic complex of Mn(II): Crystal structure, biological and DFT studies

    NASA Astrophysics Data System (ADS)

    Khanmohammadi, Hamid; Amani, Saeid; Abnosi, Mohammad H.; Khavasi, Hamid R.

    2010-10-01

    A new asymmetric heptaaza Schiff base macrocyclic bis(pendant donor) manganese(II) complex, [MnL 1](ClO 4) 2·CH 3CN ( 1), has been prepared and characterized by X-ray diffraction and spectroscopic methods. The antimicrobial activity of 1 and a series of its familiar symmetric heptaaza [15]pydieneN 5, [16]pydieneN 5, and [17]pydieneN 5-based bis-(2-aminoethyl) pendant armed Schiff base macrocyclic complexes of Mn(II) were tested against Escherichia coli, Staphylococcus aureus and Candida albicans. The results showed that the symmetric heptaaza [16]pydieneN 5, and [17]pydieneN 5-based Schiff base macrocyclic complexes of Mn(II) had remarkable inhibition zone on the culture of S. aureus and E. coli as compared with standard drugs. The optimized geometry of the prepared complex has been obtained from density functional method, DFT, using B3LYP/6-31G* basis set.

  7. 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 α-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

  8. Silver(I) complexes of 2,4-dihydroxybenzaldehyde-amino acid Schiff bases-Novel noncompetitive α-glucosidase inhibitors.

    PubMed

    Zheng, Jingwei; Ma, Lin

    2015-01-01

    A series of silver(I) complexes of 2,4-dihydroxybenzaldehyde-amino acid Schiff bases were designed and tested for α-glucosidase inhibition. Our results indicate that all the silver complexes (4a-18a) possessed strong inhibitory activity at μmolL(-1) level, especially glutamine (12a) and histidine (18a) Schiff base silver(I) complexes exhibited an IC50 value of less than 0.01μmolL(-1). This series of compounds exhibited noncompetitive inhibition characteristics in kinetic studies. In addition, we investigated the mechanism of inhibition and the structure-activity relationships of the amino acid Schiff base silver complexes. Our results reveal that Schiff base silver complexes may be explored for their therapeutic potential as alternatives of α-glucosidase inhibitors.

  9. 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 (π-π∗) 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.

  10. Synthesis, characterization, crystal structure determination and catalytic activity in epoxidation reaction of two new oxidovanadium(IV) Schiff base complexes

    NASA Astrophysics Data System (ADS)

    Tahmasebi, Vida; Grivani, Gholamhossein; Bruno, Giuseppe

    2016-11-01

    The five coordinated vanadium(IV) Schiff base complexes of VOL1 (1) and VOL2 (2), HL1 = 2-{(E)-[2-bromoethyl)imino]methyl}-2- naphthol, HL2 = 2-{(E)-[2-chloroethyl)imino]methyl}-2- naphthol, have been synthesized and they were characterized by using single-crystal X-ray crystallography, elemental analysis (CHN) and FT-IR spectroscopy. Crystal structure determination of these complexes shows that the Schiff base ligands (L1 and L2) act as bidentate ligands with two phenolato oxygen atoms and two imine nitrogen atoms in the trans geometry. The coordination geometry around the vanadium(IV) is distorted square pyramidal in which vanadium(IV) is coordinated by two nitrogen and two oxygen atoms of two independent ligands in the basal plane and by one oxygen atom in the apical position. The catalytic activity of the Schiff base complexes of 1 and 2 in the epoxidation of alkenes were investigated using different reaction parameters such as solvent effect, oxidant, alkene/oxidant ratio and the catalyst amount. The results showed that in the presence of TBHP as oxidant in 1: 4 and 1:3 ratio of the cyclooctene/oxidant ratio, high epoxide yield was obtained for 1 (76%) and 2 (80%) with TON(= mole of substrate/mole of catalyst) of 27 and 28.5, respectively, in epoxidation of cyclooctene.

  11. Induction of tumor cell apoptosis by taurine Schiff base copper complex is associated the with inhibition of proteasomal activity

    PubMed Central

    ZHANG, XIA; BI, CAIFENG; FAN, YUHUA; CUI, QIUZHI; CHEN, DI; XIAO, YAN; DOU, Q. PING

    2013-01-01

    Schiff bases have been intensively investigated due to their antibacterial and antitumor properties. Copper is a cofactor essential for the tumor angiogenesis processes, whereas other transition metals are not. Consistently, high serum or tissue levels of copper were found in many types of human cancer including breast, prostate, colon, lung, and brain, supporting the idea that copper could be used as a novel selective target for cancer therapies. In the current study we hypothesize that a synthetic taurine Schiff base copper complex (Compound 1) could suppress tumor cell growth via the direct inhibition of proteasome activity. Compound 1 potently inhibits the activity of purified 20S and 26S proteasome in human breast cancer MDA-MB-231 and leukemia Jurkat T cells. Inhibition of tumor cellular proteasomal activity by Compound 1 results in the accumulation of ubiquitinated protein and the proteasome target proteins p27 and Bax, followed by the induction of apoptosis. Our results strongly suggest that taurine Schiff base copper complexes, as potent proteasome inhibitors, have great potential to be developed into novel anticancer drugs. PMID:18949390

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

    NASA Astrophysics Data System (ADS)

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

    2010-07-01

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

  13. Comparative Study of Aluminum Complexes Bearing N,O- and N,S-Schiff Base in Ring-Opening Polymerization of ε-Caprolactone and L-Lactide.

    PubMed

    Chang, Meng-Chih; Lu, Wei-Yi; Chang, Heng-Yi; Lai, Yi-Chun; Chiang, Michael Y; Chen, Hsing-Yin; Chen, Hsuan-Ying

    2015-12-01

    A series of Al complexes bearing Schiff base and thio-Schiff base ligands were synthesized, and their application for the ring-opening polymerization of ε-caprolactone (CL) and l-lactide (LA) was studied. It was found that steric effects of the ligands caused higher polymerization rate and most importantly the Al complexes with N,S-Schiff base showed significantly higher polymerization rate than Al complexes with N,O-Schiff base (5-12-fold for CL polymerization and 2-7-fold for LA polymerization). The reaction mechanism of CL polymerization was investigated by density functional theory (DFT). The calculations predicted a lower activation energy for a process involved with an Al complex bearing an N,S-Schiff base ligand (17.6 kcal/mol) than for that of an Al complex bearing an N,O-Schiff base ligand (19.0 kcal/mol), and this magnitude of activation energy reduction is comparable to the magnitude of rate enhancement observed in the experiment. The reduction of activation energy was attributed to the catalyst-substrate destabilization effect. Using a sulfur-containing ligand to decrease the activation energy in the ring-opening polymerization process may be a new strategy to design a new Al complex with high catalytic activity.

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

    PubMed

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

    2015-01-01

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

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

    PubMed

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

    2015-01-01

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

  16. 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 γ-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.

  17. Two ferromagnetic azido-bridged copper(II) complexes studied by first-principle electronic-structure calculation

    NASA Astrophysics Data System (ADS)

    Zhang, Y. S.; Yao, K. L.; Liu, Z. L.

    2005-09-01

    The electronic structures of two ferromagnetic polynuclear copper(II) complexes, derived from end-to-end azido ligand and tridentate (NNN donor) Schiff base ligand, have been studied using the full-potential linearized augmented plane-wave method based on the density-functional theory. They are [Cu(L1)(μ-1,3-N3)]n(ClO4)n (1) and [Cu(L2)(μ-1,3-N3)]n(ClO4)n (2). The result shows that the spin populations in these two complexes are mainly distributed on the equatorial planes of a square pyramidal that surround the copper(II) ions. There are large and positive spin populations on copper(II) ions, small and positive spin populations on the three nitrogen atoms of tridentate Schiff base ligand, and the two terminal nitrogen atoms of asymmetrical end-to-end azido ligand, while weak and negative spin populations on the central nitrogen atoms of asymmetrical end-to-end azido ligand. Ferromagnetic coupling through the asymmetrical azido ligand in these two complexes has been mainly attributed to the spin delocalization, also with weak spin-polarization effect.

  18. 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.

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

    PubMed

    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, (1)H NMR, (13)C 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.

  20. Crystal structures of type I dehydroquinate dehydratase in complex with quinate and shikimate suggest a novel mechanism of Schiff base formation.

    PubMed

    Light, Samuel H; Antanasijevic, Aleksandar; Krishna, Sankar N; Caffrey, Michael; Anderson, Wayne F; Lavie, Arnon

    2014-02-11

    A component of the shikimate biosynthetic pathway, dehydroquinate dehydratase (DHQD) catalyzes the dehydration of 3-dehydroquniate (DHQ) to 3-dehydroshikimate. In the type I DHQD reaction mechanism a lysine forms a Schiff base intermediate with DHQ. The Schiff base acts as an electron sink to facilitate the catalytic dehydration. To address the mechanism of Schiff base formation, we determined structures of the Salmonella enterica wild-type DHQD in complex with the substrate analogue quinate and the product analogue shikimate. In addition, we determined the structure of the K170M mutant (Lys170 being the Schiff base forming residue) in complex with quinate. Combined with nuclear magnetic resonance and isothermal titration calorimetry data that revealed altered binding of the analogue to the K170M mutant, these structures suggest a model of Schiff base formation characterized by the dynamic interplay of opposing forces acting on either side of the substrate. On the side distant from the substrate 3-carbonyl group, closure of the enzyme's β8-α8 loop is proposed to guide DHQ into the proximity of the Schiff base-forming Lys170. On the 3-carbonyl side of the substrate, Lys170 sterically alters the position of DHQ's reactive ketone, aligning it at an angle conducive for nucleophilic attack. This study of a type I DHQD reveals the interplay between the enzyme and substrate required for the correct orientation of a functional group constrained within a cyclic substrate.

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

    PubMed

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

    2014-12-10

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

  2. 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.

  3. Chloroform-soluble schiff-base Zn(II) or Cd(II) complexes from a dynamic combinatorial library.

    PubMed

    Epstein, D M; Choudhary, S; Churchill, M R; Keil, K M; Eliseev, A V; Morrow, J R

    2001-03-26

    A dynamic combinatorial library of metal ion Schiff-base complexes have been studied for the extraction of Zn(II) or Cd(II) from aqueous solution into chloroform. Library components consist of different aminophenols and 2-pyridinecarboxaldehyde. Extraction of both Zn(II) and Cd(II) into chloroform was observed from aqueous solutions containing 0.0500 mM M(NO3)2, 0.100 M aminophenol, 0.100 M 2-pyridinecarboxaldehyde, 0.100 M NaCl, and 5.00 mM buffer at pH 8.5. Extraction was dependent on pH but not on counterions including Cl-, Br-, or NO3-. Studies showed that equilibrium was attained between the Schiff-base complexes across the two-phase chloroform-water system after 24 h of stirring. Analysis of the extracted species by use of 1H NMR spectroscopy and mass spectrometry as well as solubility studies on characterized complexes suggested that the major extracted species is the neutral bis-Schiff-base metal ion complex. In libraries containing mixtures of two different aminophenols and 2-pyridinecarboxaldehyde, an enhanced extent of extraction of Zn(II) into chloroform is observed. Studies suggest that a Zn(II) complex, which is likely the mixed Schiff-base complex, has superior extraction properties compared to simple libraries with a single aminophenol component. The structures of two bis-Schiff-base complexes of Zn(II) and one of Cd(II) have been determined by X-ray crystallography. The geometries of the two Zn(II) complexes, which differ only by a methyl substituent on the Schiff-base ligand, are markedly different, supporting the use of combinatorial methods in coordination chemistry. Zn(SB14)2 crystallized as the sesquihydrate (C24H18N4O2Zn.1.5 H2O) in the space group C2/c, with cell dimensions a = 23.219(15) A, b = 11.299(7) A, c = 16.822(11) A, beta = 102.91(5) degrees, V = 4302(5) A3, and Z = 8. Zn(SB15)2 crystallized as a 1:1 methanol solvate (C26H22N4O2Zn.CH3OH) in the space group P2(1)/c with cell dimensions a = 13.981(5) A, b = 7.978(3) A, c = 22.568(8) A

  4. Synthesis, spectroscopic, coordination and biological activities of some transition metal complexes containing ONO tridentate Schiff base ligand.

    PubMed

    Belal, A A M; El-Deen, I M; Farid, N Y; Zakaria, Rosan; Refat, Moamen S

    2015-01-01

    The main target of this paper is to get an interesting data for the preparation and characterizations of metal oxide (MO) nanoparticles using H2L Schiff base complexes as precursors through the thermal decomposition procedure. Five Schiff base complexes of Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) metal ions were synthesized from 2-[(2-hydroxy-naphthalen-1-ylmethylene)-amino]-benzoic acid new adduct (H2L). Theses complexes were characterized using infrared, electronic, mass and (1)H NMR spectroscopic techniques. The elemental analysis data was confirmed that the stoichiometry of (metal:H2L) is 1:1 molar ratio. The molar conductance indicates that all of complexes are non electrolytic. The general chemical formulas of these complexes is [M(L)(NH3)]·nH2O. All complexes are tetrahedral geometry. The thermal decomposition behavior of H2L hydrated and anhydrous complexes has been discussed using thermogravimetric analysis (TG/DTG) and differential thermal analyses (DTA) under nitrogen atmosphere. The crystalline phases of the reaction products were checked using X-ray diffractometer (XRD) and scanning electron microscopy (SEM).

  5. Synthesis, spectroscopic, coordination and biological activities of some transition metal complexes containing ONO tridentate Schiff base ligand.

    PubMed

    Belal, A A M; El-Deen, I M; Farid, N Y; Zakaria, Rosan; Refat, Moamen S

    2015-01-01

    The main target of this paper is to get an interesting data for the preparation and characterizations of metal oxide (MO) nanoparticles using H2L Schiff base complexes as precursors through the thermal decomposition procedure. Five Schiff base complexes of Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) metal ions were synthesized from 2-[(2-hydroxy-naphthalen-1-ylmethylene)-amino]-benzoic acid new adduct (H2L). Theses complexes were characterized using infrared, electronic, mass and (1)H NMR spectroscopic techniques. The elemental analysis data was confirmed that the stoichiometry of (metal:H2L) is 1:1 molar ratio. The molar conductance indicates that all of complexes are non electrolytic. The general chemical formulas of these complexes is [M(L)(NH3)]·nH2O. All complexes are tetrahedral geometry. The thermal decomposition behavior of H2L hydrated and anhydrous complexes has been discussed using thermogravimetric analysis (TG/DTG) and differential thermal analyses (DTA) under nitrogen atmosphere. The crystalline phases of the reaction products were checked using X-ray diffractometer (XRD) and scanning electron microscopy (SEM). PMID:25989615

  6. 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.

  7. 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.

  8. 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 μg/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.

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

    PubMed Central

    Abdulghani, Ahlam Jameel; Khaleel, Asmaa Mohammed Noori

    2013-01-01

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

  10. Co(II) and Cd(II) Complexes Derived from Heterocyclic Schiff-Bases: Synthesis, Structural Characterisation, and Biological Activity

    PubMed Central

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

    2013-01-01

    New monomeric cobalt and cadmium complexes with Schiff-bases, namely, N′-[(E)-(3-hydroxy-4-methoxyphenyl)methylidene]furan-2-carbohydrazide (L1) and N′-[(E)-(3-hydroxy-4-methoxyphenyl)methylidene]thiophene-2-carbohydrazide (L2) are reported. Schiff-base ligands L1 and L2 were derived from condensation of 3-hydroxy-4-methoxybenzaldehyde (iso-vanillin) with furan-2-carboxylic acid hydrazide and thiophene-2-carboxylic acid hydrazide, respectively. Complexes of the general formula [M(L)2]Cl2 (where M = Co(II) or Cd(II), L = L1 or L2) have been obtained from the reaction of the corresponding metal chloride with the ligands. The ligands and their metal complexes were characterised by spectroscopic methods (FTIR, UV-Vis, 1H, and 13C NMR spectra), elemental analysis, metal content, magnetic measurement, and conductance. These studies revealed the formation of four-coordinate complexes in which the geometry about metal ion is tetrahedral. Biological activity of the ligands and their metal complexes against gram positive bacterial strain Bacillus (G+) and gram negative bacteria Pseudomonas (G−) revealed that the metal complexes become less resistive to the microbial activities as compared to the free ligands. PMID:24027449

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

    SciTech Connect

    Yang, L.W.; Liu, S.; Wong, E.; Rettig, S.J.; Orvig, C.

    1995-04-12

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

  12. Novel Schiff base copper complexes of quinoline-2 carboxaldehyde as proteasome inhibitors in human prostate cancer cells.

    PubMed

    Adsule, Shreelekha; Barve, Vivek; Chen, Di; Ahmed, Fakhara; Dou, Q Ping; Padhye, Subhash; Sarkar, Fazlul H

    2006-11-30

    We report the synthesis of novel 1:1 Schiff base copper complexes of quinoline-2-carboxaldehyde showing dose-dependent, antiproliferative, and proapoptotic activity in PC-3 and LNCaP prostate cancer cells. We found that quinoline thiosemicarbazone 2 (FPA-137) was the most potent and inhibited proteosome activity in intact human prostate cancer PC-3 and LNCaP cells (IC50 of 4 and 3.2 microM, respectively) compared to clioquinol and pyrrolidine dithiocarbamate (IC50 of 10 and 20 microM), supporting the novelty of 2. PMID:17125278

  13. 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.

  14. 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 (β) and coefficient factor (α) 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.

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

    PubMed

    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 UO2(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*, ΔH*, ΔS* and ΔG* 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.

    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

  17. Two Types of Anion-Induced Reconstruction of Schiff-Base Macrocyclic Zinc Complexes: Ring-Contraction and Self-Assembly of a Molecular Box.

    PubMed

    Zhang, Kun; Zhang, Lei; Feng, Gen-Feng; Hu, Yong; Chang, Fei-Fan; Huang, Wei

    2016-01-01

    Two 46-membered [2 + 2] Schiff-base macrocyclic dinuclear Zn(II) complexes (1a and 1b) were investigated deeply by the postmodification strategy, and two types of supramolecular processes (ring-contraction and self-assembly) have been achieved after the addition of specific anions as stimulus for the equilibrium of Schiff-base macrocyclic complexes. Namely, in the presence of linear three-atom SCN(-), 1a was degraded into two 23-membered [1 + 1] Schiff-base macrocyclic complexes simultaneously (mononuclear Zn(II) complex 2 and dinuclear Zn(II) complex 3). In contrast, 1b was only transformed into the macrocyclic mononuclear complex 5. More interestingly, in the case of pseudolinear five-atom N(CN)2(-), supramolecular self-assembly took place instead of the above-mentioned ring-contraction. Finally, 1a was assembled into a unique molecular box 4 with two 46-membered [2 + 2] Schiff-base macrocyclic heteronuclear Zn4Na4 substrates and double μ2-N(CN)2(-) bridges, while no similar assembly process was observed for 1b. The geometry of anions and pH values slightly adjusted by the pendant arms on the macrocyclic skeletons are believed to be the critical factors for the different supramolecular processes originating from the dynamic covalent chemistry of Schiff-base imine bonds.

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

    NASA Astrophysics Data System (ADS)

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

    2011-09-01

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

  19. 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(μ-O)2(RL)]2+ 1-3(O2) and [CuIII2(μ-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(μ-O)2 form with respect to the CuII2(μ-η2: η2-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, ΔH‡ = 4.9 ± 0.5 kJ·mol−1, ΔS‡ = −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

  20. SOD activity and DNA binding properties of a new symmetric porphyrin Schiff base ligand and its metal complexes.

    PubMed

    Çay, Sevim; Köse, Muhammet; Tümer, Ferhan; Gölcü, Ayşegül; Tümer, Mehmet

    2015-12-01

    4-Methoxy-2,6-bis(hydroxymethyl)phenol (1) was prepared from the reaction of 4-methoxyphenol and formaldehyde. The compound (1) was then oxidized to the 4-methoxy-2,6-diformylphenol (2) compound. Molecular structure of compound (2) was determined by X-ray diffraction method. A new symmetric porphyrin Schiff base ligand 4-methoxy-2,6-bis[5-(4-iminophenyl)-10,15,20-triphenylporphyrin]phenol (L) was prepared from the reaction of the 5-(4-aminophenyl)-10,15,20-triphenylporphyrin (TTP-NH2) and the compound (2) in the toluene solution. The metal complexes (Cu(II), Fe(III), Mn(III), Pt(II) and Zn(II)) of the ligand (L) were synthesized and characterized by the spectroscopic and analytical methods. The DNA (fish sperm FSdsDNA) binding studies of the ligand and its complexes were performed using UV-vis spectroscopy. Additionally, superoxide dismutase activities of the porphyrin Schiff base metal complexes were investigated. Additionally, electrochemical, photoluminescence and thermal properties of the compounds were investigated.

  1. 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.

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

    PubMed

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

    2016-08-01

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

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

    PubMed

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

    2016-08-01

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

  4. Synthesis, characterization and biological activity of ferrocene-based Schiff base ligands and their metal (II) complexes

    NASA Astrophysics Data System (ADS)

    Liu, Yu-Ting; Lian, Gui-Dan; Yin, Da-Wei; Su, Bao-Jun

    Metal (II) complexes derived from S-benzyl-N-(1-ferrocenyl-3-(4-methylbenzene)acrylketone) dithiocarbazate; HL1, S-benzyl-N-(1-ferrocenyl-3-(4-chlorobenzene)acrylketone)dithiocarbazate; HL2, all the compounds were characterized using various spectroscopic techniques. The molar conductance data revealed that the chelates were non-electrolytes. IR spectra showed that the Schiff bases were coordinated to the metal ions in a bidentate manner with N, S donor sites. The ligands and their metal complexes have been screened for in vitro antibacterial, antifungal properties. The result of these studies have revealed that zinc (II) complexes 6 and 13 of both the ligands and copper (II) complexes 9 of the HL2 were observed to be the most active against all bacterial strains, antifungal activity was overall enhanced after complexation of the ligands.

  5. Synthesis, characterization and biological activity of ferrocene-based Schiff base ligands and their metal (II) complexes.

    PubMed

    Liu, Yu-Ting; Lian, Gui-Dan; Yin, Da-Wei; Su, Bao-Jun

    2013-01-01

    Metal (II) complexes derived from S-benzyl-N-(1-ferrocenyl-3-(4-methylbenzene)acrylketone) dithiocarbazate; HL(1), S-benzyl-N-(1-ferrocenyl-3-(4-chlorobenzene)acrylketone)dithiocarbazate; HL(2), all the compounds were characterized using various spectroscopic techniques. The molar conductance data revealed that the chelates were non-electrolytes. IR spectra showed that the Schiff bases were coordinated to the metal ions in a bidentate manner with N, S donor sites. The ligands and their metal complexes have been screened for in vitro antibacterial, antifungal properties. The result of these studies have revealed that zinc (II) complexes 6 and 13 of both the ligands and copper (II) complexes 9 of the HL(2) were observed to be the most active against all bacterial strains, antifungal activity was overall enhanced after complexation of the ligands.

  6. Experimental and Computational Study of the Thermodynamic Properties of Trivalent Cobalt Schiff Base Complexes with Cyclic Amines.

    PubMed

    Esmaielzadeh, Sheida; Azimian, Leila; Zar, Zohreh

    2016-01-01

    Some cobalt(III) complexes with a potentially tetradentate unsymmetrical NNOS Schiff base ligand have been synthesized and characterized using IR, 1HNMR, UV-Vis spectroscopy and elemental analysis. The equilibrium constants were measured spectrophotometrically for 1:1 adduct formation of the cobalt(III) complexes with some cyclic amines in acetonitrile as solvent at constant ionic strength (I = 0.1 M NaClO4), and at various temperatures. In addition, the ground state geometries of the complexes were optimized using density functional theory (DFT) at B3LYP/6-311G** level. Binding energy, thermodynamic parameters, structural parameters and electronic structures of complexes are investigated. The theoretical investigations were done for comparing with the experimental results. Our comparison between the computational and experimental results revealed that the cobalt(III) complexation process is spontaneous, exothermic and entropically unfavorable. PMID:27333559

  7. A novel Schiff base bearing dopamine groups with tripodal structure. Synthesis and its salen/salophen-bridged Fe/Cr(III) capped complexes

    NASA Astrophysics Data System (ADS)

    Kocyigit, Ozcan

    2013-02-01

    This work presents the synthesis of a novel Schiff base and its complexation properties with Fe(III) and Cr(III). A Schiff base bearing dopamine (TRDPA) was synthesized using dopamine hydrochloride and 1,3,5-tris (formylphenoxymethyl)benzene in methanol media. The prepared TRDPA was then reacted with four new trinuclear Fe(III) and Cr(III) complexes involving tetradenta Schiff bases N,N-bis(salicylidene)ethylenediamine-(salenH2) or bis(salicylidene)-o-phenylenediamine-(salophenH2). The structures of these compounds were characterized through 1H NMR, 13C NMR, FT-IR, thermal analysis (TG), elemental analysis, and magnetic susceptibility measurements. The complexes were also characterized as low-spin distorted octahedral Fe(III) and Cr(III) bridged by a catechol group.

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

    PubMed Central

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

    2015-01-01

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

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

    PubMed

    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, (1)H NMR, (13)C 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. PMID:25459719

  10. Synthesis of copper/nickel nanoparticles using newly synthesized Schiff-base metals complexes and their cytotoxicity/catalytic activities.

    PubMed

    Aazam, Elham S; El-Said, Waleed Ahmed

    2014-12-01

    Transition metal complexes compounds with Schiff bases ligand representing an important class of compounds that could be used to develop new metal-based anticancer agents and as precursors of metal NPs. Herein, 2,3-bis-[(3-ethoxy-2-hydroxybenzylidene)amino]but-2-enedinitrile Schiff base ligand and its corresponding copper/nickel complexes were synthesized. Also, we reported a facile and rapid method for synthesis nickel/copper nanoparticles based on thermal reduction of their complexes. Free ligand, its metal complexes and metals nanoparticles have been characterized based on elemental analysis, transmission electron microscopy, powder X-ray diffraction, magnetic measurements and by various spectroscopic (UV-vis, FT-IR, (1)H NMR, GC-MS) techniques. Additionally, the in vitro cytotoxic activity of free ligand and its complexes compounds were assessed against two cancer cell lines (HeLa and MCF-7 cells)and one healthy cell line (HEK293 cell). The copper complex was found to be active against these cancer cell lines at very low LD50 than the free ligand, while nickel complex did not show any anticancer activity against these cell lines. Also, the antibacterial activity of as-prepared copper nanoparticles were screened against Escherichia coli, which demonstrated minimum inhibitory concentration and minimum bactericidal concentration values lower than those values of the commercial Cu NPs as well as the previous reported values. Moreover, the synthesized nickel nanoparticles demonstrated remarkable catalytic performance toward hydrogenation of nitrobenzene that producing clean aniline with high selectivity (98%). This reactivity could be attributed to the high degree of dispersion of Ni nanoparticles.

  11. 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.

  12. 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.

  13. 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 VOL1ṡDMF 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 VOL1ṡDMF 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.

  14. 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.

  15. 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.

  16. Synthesis, crystal structure, fluorescence and electrochemical studies of a new tridentate Schiff base ligand and its nickel(II) and palladium(II) complexes.

    PubMed

    Shafaatian, Bita; Soleymanpour, Ahmad; Kholghi Oskouei, Nasim; Notash, Behrouz; Rezvani, Seyyed Ahmad

    2014-07-15

    A new unsymmetrical tridentate Schiff base ligand was derived from the 1:1M 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 2:1M 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, (1)H NMR, UV/Vis, elemental analyses and conductometry. The crystal structure of nickel complex has been determined by single crystal X-ray diffraction.

  17. Metal based biologically active compounds: design, synthesis, and antibacterial/antifungal/cytotoxic properties of triazole-derived Schiff bases and their oxovanadium(IV) complexes.

    PubMed

    Chohan, Zahid H; Sumrra, Sajjad H; Youssoufi, Moulay H; Hadda, Taibi B

    2010-07-01

    A new series of oxovanadium(IV) complexes have been designed and synthesized with a new class of triazole Schiff bases derived from the reaction of 3,5-diamino-1,2,4-triazole with 2-hydroxy-1-naphthaldehyde, pyrrole-2-carboxaldehyde, pyridine-2-carboxaldehyde and acetyl pyridine-2-carboxaldehyde, respectively. Physical (magnetic susceptibility, molar conductance), spectral (IR, (1)H NMR, (13)C NMR, mass and electronic) and analytical data have established the structures of these synthesized Schiff bases and their oxovanadium(IV) complexes. The Schiff bases, predominantly act as bidentate and coordinate with the vanadium(IV) metal to give a stoichiometric ratio of 1:2 [M:L], forming a general formulae, [M(L-H)(2)] and [M(L)(2)]SO(4) where L = (L(1))-(L(4)) and M = VO(IV) of these complexes in a square-pyramidal geometry. In order to evaluate the biological activity of Schiff bases and to assess the role of vanadium(IV) metal on biological activity, the triazole Schiff bases and their oxovanadium(IV) complexes have been studied for in vitro antibacterial activity against four Gram-negative (Escherichia coli, Shigella flexenari, Pseudomonas aeruginosa, Salmonella typhi) and two Gram-positive (Staphylococcus aureus, Bacillus subtilis) bacterial strains, in vitro antifungal activity against Trichophyton longifucus, Candida albican, Aspergillus flavus, Microscopum canis, Fusarium solani and Candida glaberata. The simple Schiff bases showed weaker to significant activity against one or more bacterial and fungal strains. In most of the cases higher activity was exhibited upon coordination with vanadium(IV) metal. Brine shrimp bioassay was also carried out for in vitro cytotoxic properties against Artemia salina. PMID:20338672

  18. Some biologically active oxovanadium(IV) complexes of triazole derived Schiff bases: their synthesis, characterization and biological properties.

    PubMed

    Chohan, Zahid H; Sumrra, Sajjad H

    2010-10-01

    A series of biologically active oxovanadium(IV) complexes of triazole derived Schiff bases L(1)-L(5) have been synthesized and characterized by their physical, analytical, and spectral data. The synthesized ligands potentially act as bidentate, in which the oxygen of furfural and nitrogen of azomethine coordinate with the oxovanadium atom to give a stoichiometry of vanadyl complexes 1:2 (M:L) in a square-pyramidal geometry. In vitro antibacterial and antifungal activities on different species of pathogenic bacteria (E. coli, S. flexneri, P. aeruginosa, S. typhi, S. aureus, and B. subtilis) and fungi (T. longifusus, C. albicans, A. flavus, M. canis, F. solani, and C. glabrata) have been studied. All compounds showed moderate to significant antibacterial activity against one or more bacterial strains and good antifungal activity against most of the fungal strains. The brine shrimp bioassay was also carried out to check the cytotoxicity of coordinated and uncoordinated synthesized compounds. PMID:20429776

  19. Synthesis and spectroscopic studies of some transition metal complexes of a novel Schiff base ligands derived from 5-phenylazo-salicyladehyde and o-amino benzoic acid

    NASA Astrophysics Data System (ADS)

    Refat, Moamen S.; El-Deen, Ibrahim M.; Ibrahim, Hassan K.; El-Ghool, Samir

    2006-12-01

    Cu(II), Mn(II), Ni(II), and Zn(II) metal complexes with novel heterocyclic Schiff base derived from 5-phenyl azo-salicyladehyde and o-amino benzoic acid have been synthesized and characterized on the basis of elemental analyses, electronic, IR, and 1H NMR spectra, and also by aid of scanning electron microscopy (SEM), X-ray powder diffraction, molar ratio measurements, molar conductivity measurements, and thermogravimetric analyses. It has been found that the Schiff base behaves as neutral tridentate (ONO) ligand forming chelates with 1:1 (metal:ligand) stoichiometry.

  20. Comments on "Synthesis aspects, structural, spectroscopic, antimicrobial and room temperature ferromagnetism of zinc iodide complex with Schiff based ligand" by K. Shakila and S. Kalainathan, Spectrochim. Acta 135 A (2015) 1059-1065

    NASA Astrophysics Data System (ADS)

    Srinivasan, Bikshandarkoil R.; Nadkarni, V. S.

    2016-06-01

    Shakila and Kalainathan report on the synthetic and structural aspects of a zinc iodide complex with Schiff based ligand, which exhibits room temperature ferromagnetism. In this comment, many points of criticism, concerning the characterization of this so called zinc iodide complex of Schiff based ligand are highlighted to prove that the title paper is completely erroneous.

  1. 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.

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

    PubMed

    Dhanaraj, Chellaian Justin; Johnson, Jijo

    2014-01-24

    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 (1)H NMR spectral studies. The X band ESR spectrum of the Cu(II) complex at 300 and 77K 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.

  3. 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

  4. Synthesis, spectral characterization and biological activity of zinc(II) complexes with 3-substituted phenyl-4-amino-5-hydrazino-1, 2, 4-triazole Schiff bases

    NASA Astrophysics Data System (ADS)

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

    New Zn(II) complexes have been synthesized by the reactions of zinc(II) acetate with Schiff bases derived from 3-substituted phenyl-4-amino-5-hydrazino-1, 2, 4-triazole and benzaldehyde, 2-hydroxyacetophenone or indoline-2,3-dione. All these complexes are soluble in DMF and DMSO; low molar conductance values indicate that they are non-electrolytes. Elemental analyses suggest that the complexes have 1:1 stoichiometry of the type [ZnL(H 2O) 2], [ZnL'(OAc) 2(H 2O) 2] (L = dianionic Schiff bases derived from 3-(substituted phenyl)-4-amino-5-hydrazino-1, 2, 4-triazole and 2-hydroxyacetophenone or indoline-2,3-dione; L' = neutral Schiff bases derived from 3-(substituted phenyl)-4-amino-5-hydrazino-1, 2, 4-triazole and benzaldehyde) and they were characterized by FT-IR, 1H NMR, 13C NMR and FAB mass. All these Schiff bases and their complexes have also been screened for their antibacterial activities against Bacillus subtilis, Escherichia coli and antifungal activities against Colletotrichum falcatum, Aspergillus niger, Fusarium oxysporium and Carvularia pallescence by petriplates methods.

  5. 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.

  6. DNA binding propensity and nuclease efficacy of biosensitive Schiff base complexes containing pyrazolone moiety: Synthesis and characterization

    NASA Astrophysics Data System (ADS)

    Paulpandiyan, Rajakkani; Raman, Natarajan

    2016-12-01

    A series of novel Co(II), Cu(II), Ni(II) and Zn(II) complexes (1-8) were synthesized from pyrazolone precursor Schiff base(s), obtained by the condensation of 4-amino-2,3-dimethyl-1-phenyl-3-pyrazolin-5-one (4-aminoantipyrine) with cinnamaldehyde/benzaldehyde and respective metal(II) chloride. They have been characterized by elemental analysis, magnetic susceptibility, molar conductance measurements, UV-Vis., IR, NMR, ESI mass spectra and EPR studies. These complexes show lower conductance values, supporting their non-electrolytic nature. Spectroscopic and other analytical data of the complexes suggest octahedral geometry. The binding properties of these complexes with DNA have been explored by electronic absorption spectra, cyclic voltammetry and viscosity measurements which reveal that the complexes have the ability to interact with calf thymus DNA (CT DNA) by intercalative mode. The binding constant (Kb) values clearly signify that the complex 1 has more intercalating ability than other complexes. DNA cleavage efficacy of these complexes with pUC18 DNA has been investigated by gel electrophoresis technique. All the complexes have been found to promote cleavage of pUC18 DNA from the super coiled form I to the open circular form II in presence of hydrogen peroxide. The in vitro antibacterial and antifungal assay, investigated by Minimum Inhibitory Concentration (MIC) method indicates that these complexes are good antimicrobial agents against various pathogens.

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

    PubMed

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

    2015-04-20

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

  8. 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.

  9. 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.

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

    PubMed

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

    2015-07-01

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

  11. 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.

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

    PubMed

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

    2015-07-01

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

  13. 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 α-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 μg/ml against MCF7, HCT116 and HEPG2, respectively.

  14. BaFe12O19-chitosan Schiff-base Ag (I) complexes embedded in carbon nanotube networks for high-performance electromagnetic materials

    NASA Astrophysics Data System (ADS)

    Zhao, Jie; Xie, Yu; Guan, Dongsheng; Hua, Helin; Zhong, Rong; Qin, Yuancheng; Fang, Jing; Liu, Huilong; Chen, Junhong

    2015-07-01

    The multiwalled carbon nanotubes/BaFe12O19-chitosan (MCNTs/BF-CS) Schiff base Ag (I) complex composites were synthesized successfully by a chemical bonding method. The morphology and structures of the composites were characterized with electron microscopy, Fourier transform infrared spectroscopy and X-ray diffraction techniques. Their conductive properties were measured using a four-probe conductivity tester at room temperature, and their magnetic properties were tested by a vibrating sample magnetometer. The results show that the BF-CS Schiff base Ag (I) complexes are embedded into MCNT networks. When the mass ratio of MCNTs and BF-CS Schiff base is 0.95:1, the conductivity, Ms (saturation magnetization), Mr (residual magnetization), and Hc (coercivity) of the BF-CS Schiff base composites reach 1.908 S cm-1, 28.20 emu g-1, 16.66 emu g-1 and 3604.79 Oe, respectively. Finally, a possible magnetic mechanism of the composites has also been proposed.

  15. BaFe12O19-chitosan Schiff-base Ag (I) complexes embedded in carbon nanotube networks for high-performance electromagnetic materials

    PubMed Central

    Zhao, Jie; Xie, Yu; Guan, Dongsheng; Hua, Helin; Zhong, Rong; Qin, Yuancheng; Fang, Jing; Liu, Huilong; Chen, Junhong

    2015-01-01

    The multiwalled carbon nanotubes/BaFe12O19-chitosan (MCNTs/BF-CS) Schiff base Ag (I) complex composites were synthesized successfully by a chemical bonding method. The morphology and structures of the composites were characterized with electron microscopy, Fourier transform infrared spectroscopy and X-ray diffraction techniques. Their conductive properties were measured using a four-probe conductivity tester at room temperature, and their magnetic properties were tested by a vibrating sample magnetometer. The results show that the BF-CS Schiff base Ag (I) complexes are embedded into MCNT networks. When the mass ratio of MCNTs and BF-CS Schiff base is 0.95:1, the conductivity, Ms (saturation magnetization), Mr (residual magnetization), and Hc (coercivity) of the BF-CS Schiff base composites reach 1.908 S cm−1, 28.20 emu g−1, 16.66 emu g−1 and 3604.79 Oe, respectively. Finally, a possible magnetic mechanism of the composites has also been proposed. PMID:26218269

  16. Chiral manganese (IV) complexes derived from Schiff base ligands: Synthesis, characterization, in vitro cytotoxicity and DNA/BSA interaction.

    PubMed

    Li, Zhen; Niu, Meiju; Chang, Guoliang; Zhao, Changqiu

    2015-12-01

    Two new couples of chiral manganese (IV) complexes with Schiff-base ligands, Λ-[Mn(R-L(1))2]·2(CH3OH) (Λ-1) and Δ-[Mn(S-L(1))2]·2(CH3OH) (Δ-1), Λ-[Mn(R-L(2))2]·(H2O)2 (Λ-2) and Δ-[Mn(S-L(2))2]·(H2O)2 (Δ-2), {H2L(1)=(R/S)-(±)-1-[(1-hydroxymethyl-propylimino)-methyl]-naphthalen-2-ol, H2L(2)=(R/S)-(±)-1-[(1-Hydroxymethyl-2-phenyl-ethylimino)-methyl]-naphthalen-2-ol} have been synthesized, and fully characterized by elemental analyses, UV-Vis spectrum, circular dichroism spectrum, FT-IR spectrum, mass spectrum, and single crystal X-ray diffraction (SXRD). The interaction of the four chiral Mn (IV) complexes with CT-DNA and BSA were also investigated by various spectroscopic techniques (UV-visible, fluorescence spectroscopic). The results show that the Δ-complexes exhibit more efficient CT-DNA interaction with respect to the Λ-complexes. All the complexes could quench the intrinsic fluorescence of BSA by a static quenching process. In addition, the vitro cytotoxicity of these complexes toward four kinds of cancerous cell lines (A549, HeLa, HL-60, and Caco-2) was assayed by the MTT method, which exhibited to be selectively active against certain cell lines.

  17. X-ray characterization and magnetic properties of dioxygen-bridged Cu(II) and Mn(III) Schiff base complexes.

    PubMed

    Yahsi, Yasemin

    2016-07-01

    The coordination chemistry of multinuclear metal compounds is important because of their relevance to the multi-metal active sites of various metalloproteins and metalloenzymes. Multinuclear Cu(II) and Mn(III) compounds are of interest due to their various properties in the fields of coordination chemistry, inorganic biochemistry, catalysis, and optical and magnetic materials. Oxygen-bridged binuclear Mn(III) complexes generally exhibit antiferromagnetic interactions and a few examples of ferromagnetic interactions have also been reported. Binuclear Cu(II) complexes are important due to the fact that they provide examples of the simplest case of magnetic interaction involving only two unpaired electrons. Two novel dioxygen-bridged copper(II) and manganese(III) Schiff base complexes, namely bis(μ-4-bromo-2-{[(3-oxidopropyl)imino]methyl}phenolato)dicopper(II), [Cu2(C10H10BrNO2)2], (1), and bis(diaqua{4,4'-dichloro-2,2'-[(1,1-dimethylethane-1,2-diyl)bis(nitrilomethanylylidene)]diphenolato}manganese(III)) bis{μ-4,4'-dichloro-2,2'-[(1,1-dimethylethane-1,2-diyl)bis(nitrilomethanylylidene)]diphenolato}bis[aquamanganese(III)] tetrakis(perchlorate) ethanol disolvate, [Mn(C18H16Cl2N2O2)(H2O)2]2[Mn2(C18H16Cl2N2O2)2(H2O)2](ClO4)4·2C2H5OH, (2), have been synthesized and single-crystal X-ray diffraction has been used to analyze their crystal structures. The structure analyses of (1) and (2) show that each Cu(II) atom is four-coordinated, with long weak Cu...O interactions of 2.8631 (13) Å linking the dinuclear halves of the centrosymmetric tetranucelar molecules, while each Mn(III) atom is six-coordinated. The shortest intra- and intermolecular nonbonding Mn...Mn separations are 3.3277 (16) and 5.1763 (19) Å for (2), while the Cu...Cu separations are 3.0237 (3) and 3.4846 (3) Å for (1). The magnetic susceptibilities of (1) and (2) in the solid state were measured in the temperature range 2-300 K and reveal the presence of antiferromagnetic spin

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

    NASA Astrophysics Data System (ADS)

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

    2014-06-01

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

  19. 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.

  20. 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.

  1. 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.

  2. 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].

  3. Synthesis, spectroscopic and thermal studies of some IIB group complexes with a new N 2-Schiff base ligand

    NASA Astrophysics Data System (ADS)

    Montazerozohori, Morteza; Khani, Sara; Tavakol, Hosein; Hojjati, Ahmad; Kazemi, Mostafa

    2011-10-01

    Synthesis, spectroscopic and thermal studies of some complexes of a new N 2-Schiff base ligand of N1, N2-bis((E)-2-methyl-3-phenylallylidene)ethane-1,2-diamine (L) with a general formula of MLX 2 (M = Zn(II), Cd(II) and Hg(II); X = Cl -, Br -, I -, SCN - and N 3-) are described. The ligand and its complexes were characterized by elemental analysis, molar conductance, UV-vis spectra, FT-IR spectra, MS, 1H NMR and 13C NMR spectra. The conductivity measurement as well as spectral data indicated that the complexes are non-electrolyte. 1H and 13C NMR spectra have been studied in DMSO-d 6 and/or CDCl 3. The thermal behavior of the complexes shows weight loss by decomposition of the anions and ligand segments in the subsequent steps. Activation thermodynamic parameters of decomposition such as E*, Δ H*, Δ S* and Δ G* were calculated from TG curves.

  4. Aggregation properties of bis(salicylaldiminato)zinc(II) Schiff-base complexes and their Lewis acidic character.

    PubMed

    Consiglio, Giuseppe; Failla, Salvatore; Finocchiaro, Paolo; Oliveri, Ivan Pietro; Di Bella, Santo

    2012-01-14

    The synthesis, characterization, (1)H NMR, optical absorption and fluorescent properties of a series of amphiphilic Schiff-base bis(salicylaldiminato)zinc(II) complexes are reported. Detailed (1)H NMR, DOSY NMR, optical absorption and fluorescence spectroscopy studies indicate the existence of aggregate species in solutions of non-coordinating solvents. The degree of aggregation is related to the nature of the bridging diamine. Chloroform solutions of complexes where the bridging diamine contains a naphthalene or the pyridine nucleus are always characterized by the presence of defined dimer aggregates, whereas oligomeric aggregates are likely formed by complexes where the bridging diamine contains a benzene ring. In coordinating solvents or in the presence of coordinating species, a complete deaggregation of the complexes occurs, because of the axial coordination to the Zn(II) ion, accompanied by considerable changes in the (1)H NMR and optical absorption spectra. The effect of the alkyl chains length seems to play a minor role in the aggregation properties, as noticed by (1)H NMR data, optical absorption and fluorescence spectra, which remain almost unaltered on changing the chain length. PMID:22005842

  5. 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.

  6. Synthesis, characterization and catecholase-like activity of new Schiff base metal complexes derived from visnagin: Theoretical and experimental study

    NASA Astrophysics Data System (ADS)

    Beyazit, Neslihan; Çatıkkaş, Berna; Bayraktar, Şahin; Demetgül, Cahit

    2016-09-01

    A new tetradentate, unsymmetrical Schiff base ligand (H2L) containing a donor set of N2O2 and its mononuclear Cu(II) and Fe(II) complexes ([CuL] and [FeL]), were synthesized and characterized on the basis of their elemental analysis, FT-IR, Raman, 1H and 13C NMR spectra, electronic and mass spectra, molar conductivity and magnetic susceptibility measurements. Density functional theory (DFT) calculations were performed in order to clarify molecular structures, 1H NMR and 13C NMR chemical shift values, frontier molecular orbitals (FMOs), nonlinear optical properties and map of molecular electrostatic potential (MEP) of the title molecules. In agreement with trials, the results provide a full explanation of the highest efficiency observed for the compounds in relation to the electronic and the structural characteristics. The catecholase-like activity of the complexes toward the oxidation of 3,5-di-tert-butylcatechol (3,5-DTBC) to the corresponding quinone showed that both complexes have moderate catalytic activity. [FeL] shows higher activity (kcat = 26.4 h-1) than that of [CuL] (kcat = 23.4 h-1).

  7. 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 μm.

  8. 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.

    PubMed

    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 (1)H, (13)C 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 μm.

  9. Syntheses, characterization, biological activity and fluorescence properties of bis-(salicylaldehyde)-1,3-propylenediimine Schiff base ligand and its lanthanide complexes.

    PubMed

    Taha, Ziyad A; Ajlouni, Abdulaziz M; Al-Hassan, Khader A; Hijazi, Ahmed K; Faiq, Ari B

    2011-10-15

    Eight new lanthanide metal complexes [LnL(NO(3))(2)]NO(3) {Ln(III) = Nd, Dy, Sm, Pr, Gd, Tb, La and Er, L = bis-(salicyladehyde)-1,3-propylenediimine Schiff base ligand} were prepared. These complexes were characterized by elemental analysis, thermogravimetric analysis (TGA), molar conductivity measurements and spectral studies ((1)H NMR, FT-IR, UV-vis, and luminescence). The Schiff base ligand coordinates to Ln(III) ion in a tetra-dentate manner through the phenolic oxygen and azomethine nitrogen atoms. The coordination number of eight is achieved by involving two bi-dentate nitrate groups in the coordination sphere. Sm, Tb and Dy complexes exhibit the characteristic luminescence emissions of the central metal ions attributed to efficient energy transfer from the ligand to the metal center. Most of the complexes exhibit antibacterial activity against a number of pathogenic bacteria.

  10. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2015-05-01

    A series of two biologically active Schiff base ligands L1, L2 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 1H 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.

  12. Temperature-induced solid-state valence tautomeric interconversion in two cobalt-Schiff base diquinone complexes.

    PubMed

    Cador, Olivier; Chabre, Françoise; Dei, Andrea; Sangregorio, Claudio; van Slageren, Joris; Vaz, Maria G F

    2003-10-01

    The mixed-ligand complexes [Co(III)(tpy)(Cat-N-SQ)]Y and [Ni(II)(tpy)(Cat-N-BQ)]PF(6) (tpy = 2,2':6',2' '-terpyridine; Cat-N-BQ, Cat-N-SQ = mononegative and radical dinegative Schiff base diquinone ligand; Y = PF(6), BPh(4)) were prepared. Structural and spectroscopic data support the different charge distribution of the two compounds. The temperature-dependent electronic and spectral properties of solutions containing the [Co(III)(tpy)(Cat-N-SQ)](+) suggest that this compound undergoes a thermally driven valence tautomeric interconversion to [Co(II)(tpy)(Cat-N-BQ)](+) complex, the metal ion being in high-spin configuration. The comparison of the electrochemical properties of the cobalt and nickel derivatives supports the observed behavior. The same interconversion process was found to occur also in the solid state with a significant higher T(c) value than in solution. It was found that the previously reported [Co(III)(Cat-N-BQ)(Cat-N-SQ)] shows a similar behavior. The large difference between the interconversion T(c) in the solid state and in solution is suggested to come from the entropy changes associated with the modifications of vibronic interactions.

  13. Synthesis and characterization of water soluble O-carboxymethyl chitosan Schiff bases and Cu(II) complexes.

    PubMed

    Baran, Talat; Menteş, Ayfer; Arslan, Hülya

    2015-01-01

    In this study, mono-imine was synthesized (3a and 4a) via a condensation reaction between 2,4-pentadion and aminobenzoic acid (meta or para) in alcohol (1:1). The second-imine (CS-3a and CS-4a) was obtained as a result of the reaction of the free oxo groups of mono-imine (3a and 4a) with the amino groups on the chitosan (CS). Their structures were characterized with FTIR and (13)C CP-MAS. Then, the water soluble forms of CS-3a and CS-4a were obtained through oxidation of the hydroxide groups on the chitosan to carboxymethyl groups using monochloracetic acid ([O-CMCS-3a] · 2H2O and [O-CMCS-4a] · 2H2O). Thus, the solubility problem of chitosan in an aqueous media was overcome and Cu(II) complexes could be synthesized more easily. Characterization of the synthesized O-carboxymethyl chitosan Schiff base derivatives and their metal complexes, [O-CMCS-3a-Cu(OAc)2] · 2H2O and [O-CMCS-4a-Cu(OAc)2] · 2H2O, was conducted using FTIR, UV-Vis, TG/DTA, XRD, SEM, elemental analysis, conductivities and magnetic susceptibility measurements. PMID:25128824

  14. 5-Aminotetrazole induces spin crossover in iron(III) pentadentate Schiff base complexes: experimental and theoretical investigations.

    PubMed

    Herchel, Radovan; Trávníček, Zdeněk

    2013-12-14

    A series of novel mononuclear iron(III) complexes [Fe(saldpt)(atz)] (1) and [Fe(Rsalpet)(atz)] (2a-d) involving 5-aminotetrazole (Hatz) and pentadentate Schiff base ligands (H2saldpt = N,N'-bis(2-hydroxybenzyliden)-1,7-diamino-4-azaheptane, H2salpet = N,N'-bis(2-hydroxybenzyliden)-1,6-diamino-3-azahexane, H25Cl-salpet = N,N'-bis(5-chloro-2-hydroxybenzylidene)-1,6-diamino-3-azahexane, H25Br-salpet = N,N'-bis(5-bromo-2-hydroxybenzylidene)-1,6-diamino-3-azahexane and H23,5Br-salpet = N,N'-bis(3,5-dibromo-2-hydroxybenzylidene)-1,6-diamino-3-azahexane) was prepared and characterized by elemental analysis, FTIR spectroscopy, mass spectrometry, single crystal X-ray analysis, magnetic measurements and (57)Fe Mössbauer spectroscopy. In contrast to the high-spin magnetic properties of [Fe(saldpt)(atz)] (1), the complexes [Fe(Rsalpet)(atz)] (2a-d) undergo spin crossover with critical temperatures above 416 K. Furthermore, DFT calculations with the B3LYP functional were employed to investigate the effect of the conductor-like screening model (COSMO) and van der Waals corrections (VDW) as well as relativistic effects with the scalar relativistic second-order Douglas-Kroll-Hess Hamiltonian (DKH2) on low-spin and high-spin molecular geometries and thus on spin crossover parameters (enthalpy, entropy and critical temperature). PMID:24121719

  15. 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

  16. L-Ornithine Schiff base-copper and -cadmium complexes as new proteasome inhibitors and apoptosis inducers in human cancer cells.

    PubMed

    Zhang, Zhongyu; Bi, Caifeng; Fan, Yuhua; Zhang, Nan; Deshmukh, Rahul; Yan, Xingchen; Lv, Xiuwen; Zhang, Pengfei; Zhang, Xia; Dou, Q Ping

    2015-01-01

    Ubiquitin-proteasome system (UPS) plays a crucial role in many cellular processes such as cell cycle, proliferation and apoptosis. Aberrant activation of UPS may result in cellular transformation or other altered pathological conditions. Previous studies have shown that metal-based complexes could inhibit proteasome activity and induce apoptosis in certain human cancer cells. In the current study, we report that the cadmium and copper complexes with heterocycle-ornithine Schiff base are potent inhibitors of proteasomal chymotrypsin-like (CT-like) activity, leading to induction of apoptosis in cancer cells. Two novel copper-containing complexes and two novel cadmium-containing complexes with different heterocycle-ornithine Schiff base structures as ligands were synthesized and characterized. We found that complexes Cu1, Cd1 and Cd2 show proteasome-inhibitory activities in human breast cancer MDA-MB-231 and human prostate cancer LNCaP cells, resulting in the accumulation of p27, a natural proteasome substrate and other ubiquitinated proteins, followed by the induction of apoptosis. Our results suggest that metal complexes with heterocycle-ornithine Schiff base have proteasome-inhibitory capabilities and have the potential to be developed into novel anticancer drugs.

  17. Herbo-mineral based Schiff base ligand and its metal complexes: Synthesis, characterization, catalytic potential and biological applications.

    PubMed

    Kareem, Abdul; Laxmi; Arshad, Mohammad; Nami, Shahab A A; Nishat, Nahid

    2016-07-01

    Schiff base ligand, (L), derived from condensation reaction of 1,7-bis-(4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5-dione, (curcumin), with pyridine-3-carboxamide, (nicotinamide), and its complexes of Co(II), Ni(II) and Cu(II) ions, containing 1,10-phenanthroline as auxiliary ligand were synthesized and characterized by various physico-chemical techniques. From the micro analytical data, the stoichiometry of the complexes 1:1 (metal: ligand) was ascertained. The Co(II) and Cu(II) forms octahedral complexes, while the geometric structure around Ni(II) atom can be described as square planar. The catalytic potential of the metal complexes have been evaluated by recording the rate of decomposition of hydrogen peroxide. The results reveal that the percent decomposition of H2O2increases with time and the highest value (50.50%) was recorded for Co(II) complex. The ligand and its complexes were also screened for their in vitro antibacterial activity against Escherichia coli, Staphylococcus aureus, Klebsiella pneumoniae, Streptococcus pyogenes and Pseudomonas aeruginosa. The relative order of antibacterial activity against S. Pyogenes, S. aureus and E. coli is Cu(II)>Ni(II)>Co(II)>(L); while with P. aeruginosa, K. pneumoniae the order of activity is Cu(II)>Co(II)>Ni(II)>(L). The anthelmintic screening was performed using Pheretima posthuma. The order of anthelmintic activity of ligand and its complexes is [(Phen)CuLCl2]>[(Phen)CoLCl2]>[(Phen)NiL]Cl2>(L).

  18. Herbo-mineral based Schiff base ligand and its metal complexes: Synthesis, characterization, catalytic potential and biological applications.

    PubMed

    Kareem, Abdul; Laxmi; Arshad, Mohammad; Nami, Shahab A A; Nishat, Nahid

    2016-07-01

    Schiff base ligand, (L), derived from condensation reaction of 1,7-bis-(4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5-dione, (curcumin), with pyridine-3-carboxamide, (nicotinamide), and its complexes of Co(II), Ni(II) and Cu(II) ions, containing 1,10-phenanthroline as auxiliary ligand were synthesized and characterized by various physico-chemical techniques. From the micro analytical data, the stoichiometry of the complexes 1:1 (metal: ligand) was ascertained. The Co(II) and Cu(II) forms octahedral complexes, while the geometric structure around Ni(II) atom can be described as square planar. The catalytic potential of the metal complexes have been evaluated by recording the rate of decomposition of hydrogen peroxide. The results reveal that the percent decomposition of H2O2increases with time and the highest value (50.50%) was recorded for Co(II) complex. The ligand and its complexes were also screened for their in vitro antibacterial activity against Escherichia coli, Staphylococcus aureus, Klebsiella pneumoniae, Streptococcus pyogenes and Pseudomonas aeruginosa. The relative order of antibacterial activity against S. Pyogenes, S. aureus and E. coli is Cu(II)>Ni(II)>Co(II)>(L); while with P. aeruginosa, K. pneumoniae the order of activity is Cu(II)>Co(II)>Ni(II)>(L). The anthelmintic screening was performed using Pheretima posthuma. The order of anthelmintic activity of ligand and its complexes is [(Phen)CuLCl2]>[(Phen)CoLCl2]>[(Phen)NiL]Cl2>(L). PMID:27107703

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

    PubMed

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

    2015-06-01

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

  20. 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).

  1. 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

  2. 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.

  3. (E)3-2-(1-(2,4-Dihydroxyphenyl)ethyldeneamino)phenyl)-2-methylquinazoline-4(3H)-one Schiff Base and Its Metal Complexes: A New Drug of Choice against Methicillin-Resistant Staphylococcus aureus

    PubMed Central

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

    2014-01-01

    The 3-(2-aminophenyl) quinazolin-2-methyl-4(3H)-one and 2,4-dihydroxyacetophenone undergo condensation to afford (E)3-2-(1-(2,4-dihydroxyphenyl)ethyldeneamino)phenyl)-2-methylquinazoline-4(3H)-one Schiff base (DHPEAPMQ). The newly synthesized Schiff base (DHPEAPMQ) and its metal complexes were evaluated for their antimicrobial activity against methicillin-resistant Staphylococcus aureus isolated from the Gulbarga region in India. The Cu(II), Ni(II), and Zn(II) complexes of Schiff base (DHPEAPMQ) showed good antimicrobial activity. So, this could be a new drug of choice. PMID:24733996

  4. 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)

    Şahin, Mustafa; Koçak, Nuriye; Erdenay, Damla; Arslan, Uğur

    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.

  5. Investigation of the active site at the deuterated Schiff-base complex formed between the coenzyme vitamin B 6 and the primary amine

    NASA Astrophysics Data System (ADS)

    Lee, Min-Hee; Kim, Bo-Ra; Kim, Ho-Tae

    2007-07-01

    The Schiff-base complex ion formed between the vitamin B 6 molecule and the primary amine was investigated by electrospray ionization MS/MS in the gas phase. The two observed fragments at the MS/MS spectrum were different from the normal alkene loss (Onium reaction or McLafferty rearrangement) fragments of immonium ions. The R-CH-ND loss fragment from the 3H/D-deuterated Schiff-base complex ion was observed as one of two fragments in the MS/MS spectrum. The R-CH-ND loss fragment is thought to have originated from the simultaneous effect of a 3-OH functional group and a pyridine ring in the immonium ion.

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

    PubMed

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

    2014-11-11

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

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

    NASA Astrophysics Data System (ADS)

    Keskioğlu, Eren; Gündüzalp, Ayla Balaban; Çete, Servet; Hamurcu, Fatma; Erk, Birgül

    2008-08-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-11-01

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

  9. Catalytic asymmetric Michael addition of α,β-unsaturated aldehydes to Ni(II) complexes of the Schiff base of glycine.

    PubMed

    Luo, Xiaoyan; Jin, Zhichao; Li, Pengfei; Gao, Jiabin; Yue, Weimin; Liang, Xinmiao; Ye, Jinxing

    2011-02-01

    The conjugate addition of Ni(II) complexes of glycine Schiff base to α,β-unsaturated aldehydes catalyzed by (S)-2-(diphenyl(trimethylsilyloxy)methyl)pyrrolidine afforded adducts in excellent yields with up to 49:1 dr and 95% ee. This method enables the construction of two adjacent chiral centers in one step, and offers an alternative route to chiral α-amino acid derivatives. PMID:21103550

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

    NASA Astrophysics Data System (ADS)

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

    2010-03-01

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

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

    PubMed

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

    2011-09-01

    A mesogenic Schiff-base, N,N'-di-(4-decyloxysalicylidene)-1',6'-diaminohexane, H2ddsdh (abbreviated as H2L2) that exhibits smectic-B (SmB) mesophase, was synthesized and its structure studied by elemental analysis, mass spectrometry, NMR & IR spectral techniques. The Schiff-base, H2L2, upon condensation with hydrated lanthanide(III) nitrates, yields LnIII complexes of the general composition [Ln2(L2H2)3(NO3)4](NO3)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 L2H2) to the LnIII ions through two phenolate oxygens. The POM and DSC studies reveal that none of the LnIII complexes exhibits mesomorphism. Fluorescence studies show that the TbIII complex displays characteristic metal-centered fluorescence (solution state).

  12. Synthesis, characterization and catalytic oxidation properties of multi-wall carbon nanotubes with a covalently attached copper(II) salen complex

    NASA Astrophysics Data System (ADS)

    Salavati-Niasari, Masoud; Bazarganipour, Mehdi

    2009-06-01

    Hydroxyl functionalized copper(II) Schiff-base, N,N'-bis(4-hydroxysalicylidene)-ethylene-1,2-diaminecopper(II), [Cu((OH) 2-salen)], has been covalently anchored on modified MWCNTs. The new modified MWCNTs ([Cu((OH) 2-salen)]-MWCNTs) have been characterized by TEM, thermal analysis, XRD, XPS, UV-vis, DRS, FT-IR spectroscopy and elemental analysis. The modified copper(II) MWCNTs solid was used to affect the catalytic oxidation of ethylbenzene with tert-butylhydroperoxide as the oxidant at 333 K. The system is truly heterogeneous (no leaching observed) and reusable (no decrease in activity) in three consecutive runs. Acetophenone was the major product though small amounts of o- and p-hydroxyacetophenones were also formed revealing that C-H bond activation takes place both at benzylic and aromatic ring carbon atoms. Ring hydroxylation was more over the "neat" complexes than over the encapsulated complexes.

  13. Syntheses, crystal structures, anticancer activities of three reduce Schiff base ligand based transition metal complexes

    NASA Astrophysics Data System (ADS)

    Chang, Hui-Qin; Jia, Lei; Xu, Jun; Zhu, Tao-Feng; Xu, Zhou-Qing; Chen, Ru-Hua; Ma, Tie-Liang; Wang, Yuan; Wu, Wei-Na

    2016-02-01

    Three nickel(II) complexes, [Ni2(L1)2(tren)2(H2O)](ClO4)3 (1), [NiL2(tren)2](ClO4)·2.5H2O (2), [NiL2(tren)2]I·1.5H2O·CH3OH (3) based on amino acid reduced Schiff ligands are synthesized and characterized by physico-chemical and spectroscopic methods. The results show that in all complexes, the amino acid ligand is deprotonated and acts as an anionic ligand. In the dinuclear complex 1, each Ni(II) atom has a distorted octahedron geometry while with different coordination environment. However, the complexes 2 and 3 are mononuclear, almost with the same coordination environment. Furthermore, in vitro experiments are carried out, including MTT assay, Annexin V/PI flow cytometry and western blotting, to assess whether the complexes have antitumor effect. And the results show that all the three complexes have moderate anticancer activity towards human hepatic cancer (HepG2), human cervical cancer (HeLa) and human prostate (PC3) cell lines, in a concentration dependent way. The complex 1 exhibit higher cytotoxicity than the other two complexes and can induce human hepatic cancer cell (HepG2) to cell apoptosis by activating caspase 3.

  14. Syntheses, crystal structures, anticancer activities of three reduce Schiff base ligand based transition metal complexes

    NASA Astrophysics Data System (ADS)

    Chang, Hui-Qin; Jia, Lei; Xu, Jun; Zhu, Tao-Feng; Xu, Zhou-Qing; Chen, Ru-Hua; Ma, Tie-Liang; Wang, Yuan; Wu, Wei-Na

    2016-02-01

    Three nickel(II) complexes, [Ni2(L1)2(tren)2(H2O)](ClO4)3 (1), [NiL2(tren)2](ClO4)·2.5H2O (2), [NiL2(tren)2]I·1.5H2O·CH3OH (3) based on amino acid reduced Schiff ligands are synthesized and characterized by physico-chemical and spectroscopic methods. The results show that in all complexes, the amino acid ligand is deprotonated and acts as an anionic ligand. In the dinuclear complex 1, each Ni(II) atom has a distorted octahedron geometry while with different coordination environment. However, the complexes 2 and 3 are mononuclear, almost with the same coordination environment. Furthermore, in vitro experiments are carried out, including MTT assay, Annexin V/PI flow cytometry and western blotting, to assess whether the complexes have antitumor effect. And the results show that all the three complexes have moderate anticancer activity towards human hepatic cancer (HepG2), human cervical cancer (HeLa) and human prostate (PC3) cell lines, in a concentration dependent way. The complex 1 exhibit higher cytotoxicity than the other two complexes and can induce human hepatic cancer cell (HepG2) to cell apoptosis by activating caspase 3.

  15. Synthesis, structures and urease inhibitory activity of cobalt(III) complexes with Schiff bases.

    PubMed

    Jing, Changling; Wang, Cunfang; Yan, Kai; Zhao, Kedong; Sheng, Guihua; Qu, Dan; Niu, Fang; Zhu, Hailiang; You, Zhonglu

    2016-01-15

    A series of new cobalt(III) complexes were prepared. They are [CoL(1)(py)3]·NO3 (1), [CoL(2)(bipy)(N3)]·CH3OH (2), [CoL(3)(HL(3))(N3)]·NO3 (3), and [CoL(4)(MeOH)(N3)] (4), where L(1), L(2), L(3) and L(4) are the deprotonated form of N'-(2-hydroxy-5-methoxybenzylidene)-3-methylbenzohydrazide, N'-(2-hydroxybenzylidene)-3-hydroxylbenzohydrazide, 2-[(2-dimethylaminoethylimino)methyl]-4-methylphenol, and N,N'-bis(5-methylsalicylidene)-o-phenylenediamine, respectively, py is pyridine, and bipy is 2,2'-bipyridine. The complexes were characterized by infrared and UV-Vis spectra, and single crystal X-ray diffraction. The Co atoms in the complexes are in octahedral coordination. Complexes 1 and 4 show effective urease inhibitory activities, with IC50 values of 4.27 and 0.35 μmol L(-1), respectively. Complex 2 has medium activity against urease, with IC50 value of 68.7 μmol L(-1). While complex 3 has no activity against urease. Molecular docking study of the complexes with Helicobacter pylori urease was performed.

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

    NASA Astrophysics Data System (ADS)

    Yadav, Sunita; Singh, R. V.

    2011-01-01

    Biological important complexes of boron(III) derived from 1-acetylferrocenehydrazinecarboxamide (L 1H), 1-acetylferrocenehydrazinecarbothioamide (L 2H) and 1-acetylferrocene carbodithioic acid (L 3H) 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.

  17. 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.

  18. Substituent effects on spin state in a series of mononuclear manganese(III) complexes with hexadentate Schiff-Base ligands.

    PubMed

    Gildea, Brendan; Harris, Michelle M; Gavin, Laurence C; Murray, Caroline A; Ortin, Yannick; Müller-Bunz, Helge; Harding, Charles J; Lan, Yanhua; Powell, Annie K; Morgan, Grace G

    2014-06-16

    Eleven new mononuclear manganese(III) complexes prepared from two hexadentate ligands, L1 and L2, with different degrees of steric bulk in the substituents are reported. L1 and L2 are Schiff bases resulting from condensation of N,N'-bis(3-aminopropyl)ethylenediamine with 3-methoxy-2-hydroxybenzaldehyde and 3-ethoxy-2-hydroxybenzaldehyde respectively, and are members of a ligand series we have abbreviated as R-Sal2323 to indicate the 323 alkyl connectivity in the starting tetraamine and the substitution (R) on the phenolate ring. L1 hosts a methoxy substituent on both phenolate rings, while L2 bears a larger ethoxy group in the same position. Structural and magnetic properties are reported in comparison with those of a previously reported analogue with L1, namely, [MnL1]NO3, (1e). The BPh4(-) and PF6(-) complexes [MnL1]BPh4, (1a), [MnL2]BPh4, (2a), [MnL1]PF6, (1b'), and [MnL2]PF6, (2b), with both ligands L1 and L2, remain high-spin (HS) over the measured temperature range. However, the monohydrate of (1b') [MnL1]PF6·H2O, (1b), shows gradual spin-crossover (SCO), as do the ClO4(-), BF4(-), and NO3(-) complexes [MnL1]ClO4·H2O, (1c), [MnL2]ClO4, (2c), [MnL1]BF4·H2O, (1d), [MnL2]BF4·0.4H2O, (2d), [MnL1]NO3, (1e), and [MnL2]NO3·EtOH, (2e). The three complexes formed with ethoxy-substituted ligand L2 all show a higher T1/2 than the analogous complexes with methoxy-substituted ligand L1. Analysis of distortion parameters shows that complexes formed with the bulkier ligand L2 exhibit more deformation from perfect octahedral geometry, leading to a higher T1/2 in the SCO examples, where T1/2 is the temperature where the spin state is 50% high spin and 50% low spin. Spin state assignment in the solid state is shown to be solvate-dependent for complexes (1b) and (2e), and room temperature UV-visible and NMR spectra indicate a solution-state spin assignment intermediate between fully HS and fully low spin in 10 complexes, (1a)-(1e) and (2a)-(2e). PMID:24901836

  19. Evaluation of a Schiff base copper complex compound as potent anticancer molecule with multiple targets of action.

    PubMed

    Chakraborty, Ajanta; Kumar, Pramod; Ghosh, Kaushik; Roy, Partha

    2010-11-25

    Copper is a biologically relevant metal as it is associated with various biomolecules related to essential physiological activities. Anticancer compounds with copper as a metal center is hypothesized to be less toxic and more potent. In the present study we have tested the efficacy of a family of Schiff base copper complexes of which the best compound was [Cu(Pyimpy)Cl(2)] where Pyimpy is a tridentate ligand containing two pyridine and one imine nitrogen donor. [Cu(Pyimpy)Cl(2)], represented as CuP1, was checked for its anticancer potential. The IC(50) value of CuP1 was found to be 4.29±0.42, 6.34±0.58 and 5.32±0.38 μM in MCF-7, PC3 and HEK 293 cells respectively. It was found to cause in vitro DNA fragmentation in comet assays and acridine orange staining of MCF 7 cells. CuP1 was further tested on rat breast tumor models and was found to inhibit tumor growth. It caused apoptosis within the tumor by the up regulation of caspase pathway and inhibition of the Akt, matrix metalloproteinase 9 and α-methyl acyl CoA racemase. Antioxidant enzymes which in general results in drug resistant condition in tumor tissues were significantly inhibited by this copper compound (P<0.05). Further, CuP1 did not show any prominent systemic toxicity. These results indicate that CuP1 can be a potential anticancer agent and further investigation will reveal more about its mode of action. PMID:20797395

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

    NASA Astrophysics Data System (ADS)

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

    2015-02-01

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

  1. Metal complexes of Schiff base derived from sulphametrole and o-vanilin . Synthesis, spectral, thermal characterization and biological activity

    NASA Astrophysics Data System (ADS)

    Mohamed, Gehad G.; Sharaby, Carmen M.

    2007-04-01

    Metal complexes of Schiff base derived from condensation of o-vanilin (3-methoxysalicylaldehyde) and sulfametrole [ N1-(4-methoxy-1,2,5-thiadiazole-3-yl)sulfanilamide] (H 2L) are reported and characterized based on elemental analyses, IR, 1H NMR, solid reflectance, magnetic moment, molar conductance, mass spectra, UV-vis and thermal analysis (TGA). From the elemental analyses data, the complexes were proposed to have the general formulae [M 2X 3(HL)(H 2O) 5]· yH 2O (where M = Mn(II), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II), X = Cl, y = 0-3); [Fe 2Cl 5(HL)(H 2O) 3]·2H 2O; [(FeSO 4) 2(H 2L)(H 2O) 4] and [(UO 2) 2(NO 3) 3(HL)(H 2O)]·2H 2O. The molar conductance data reveal that all the metal chelates were non-electrolytes. The IR spectra show that, H 2L is coordinated to the metal ions in a tetradentate manner with ON and NO donor sites of the azomethine-N, phenolic-OH, enolic sulphonamide-OH and thiadiazole-N. 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*, Δ H*, Δ S* and Δ G* are calculated from the DrTG curves using Coats-Redfern method. The synthesized ligand, in comparison to their metal complexes also were screened for their antibacterial activity against bacterial species, Escherichia coli, Salmonella typhi, Bacillus subtillus, Staphylococcus aureus and Fungi ( Aspergillus terreus and Aspergillus flavus). The activity data show that the metal complexes to be more potent/antimicrobial than the parent Shciff base ligand against one or more microbial species.

  2. Mixed ligand complexes of bis(phenylimine) Schiff base ligands incorporating pyridinium moiety. Synthesis, characterization and antibacterial activity

    NASA Astrophysics Data System (ADS)

    Mohamed, Gehad G.; El-Wahab, Zeinab H. Abd

    2005-04-01

    The synthesis and structural characterization of mixed ligand complexes derived from 2,6-pyridinedicarboxaldehydebis( o-hydroxyphenylimine), 2,6-pyridinedicarboxaldehydebis( p-hydroxyphenylimine) (1 ry ligands) and 2-aminopyridne (2 ry ligand) are reported. The ligands and their transition metal complexes were characterized on the bases of their elemental analyses, IR, solid reflectance, magnetic moment, molar conductance and thermal analysis (TGA). The mixed ligand complexes are formed in the 1:1:1 (M:L 1 or L 2:L') ratio as found from the elemental analyses and found to have the formulae [MX 2(L 1 or L 2)(L')]· nH 2O where M = Co(II), Ni(II), Cu(II) and Zn(II), L 1 = 2,6-pyridinedicarboxaldehydebis( p-hydroxyphenylimine), L 2 = 2,6-pyridine dicarboxaldehydebis( o-hydroxyphenylimine), L' = 2-aminopyridine, X = Cl - in case of Cu(II) complex and Br - in case of Co(II), Ni(II) and Zn(II) complexes and y = 0-3. The molar conductance data reveal that the chelates are non-electrolytes. IR spectra show that the Schiff bases are coordinated to the metal ions in a terdentate manner with NNN donor sites of the pyridine- N and two azomethine- N. While 2-aminopyridine coordinated to the metal ions via its pyridine- N. Magnetic and solid reflectance spectra are used to infer the coordinating capacity of the ligand and the geometrical structure of these complexes are found to be octahedral. The thermal behaviour of these chelates shows that the hydrated water molecules and the anions are removed in a successive two steps followed immediately by decomposition of the ligands (L 1, L 2 and L') in the subsequent steps. The activation thermodynamic parameters, such as, E*, Δ H*, Δ S* and Δ G* are calculated from the TG curves and discussed. The ligands and their metal chelates have been screened for their antimicrobial activities and the findings have been reported, explained and compared with some known antibiotics.

  3. Homochiral mononuclear Dy-Schiff base complexes showing field-induced double magnetic relaxation processes.

    PubMed

    Ren, Min; Xu, Zhong-Li; Wang, Ting-Ting; Bao, Song-Song; Zheng, Ze-Hua; Zhang, Zai-Chao; Zheng, Li-Min

    2016-01-14

    A pair of enantiopure mononuclear dysprosium/salen-type complexes (Et3NH)[Dy((R,R)/(S,S)-3-NO2salcy)2] (/), where 3-NO2salcyH2 represents N,N'-(1,2-cyclohexanediylethylene)bis(3-nitrosalicylideneiminato), are reported. The enantiomer contains two crystallographically independent dysprosium(iii) ions, each chelated by two enantiopure 3-NO2salcy(2-) ligands forming a [DyN4O4] core. Detailed magnetic studies on compound reveal a field-induced dual magnetic relaxation behavior, originating from single ion anisotropy and intermolecular interactions, respectively. PMID:26621766

  4. A new family of Fe2Ln complexes built from mononuclear anionic Schiff base subunits.

    PubMed

    Nemec, Ivan; Machata, Marek; Herchel, Radovan; Boča, Roman; Trávníček, Zdeněk

    2012-12-28

    A series of the trinuclear [{Fe(3MeO-L)(2)}(2){μ(6)-Ln(η(2)-NO(3))(H(2)O)}]·nH(2)O, (Ln = Gd (2a), Tb (2b), Dy (2c), Ho (2d), Er (2e), Y (2f), H(2)-3MeO-L = 2-hydroxy-3-methoxy-phenylsalicylaldimine) complexes were prepared and thoroughly characterized. The crystal structure of 2bwas determined and it revealed that the heterotrinuclear complex consists of two anionic [Fe(3MeO-L)(2)](-) subunits coordinated to the [Tb(H(2)O)(η(2)-NO(3))](2+) bridging moiety through the phenolato and methoxy oxygen atoms. The angular distortion within the coordination polyhedron of the [Fe(3MeO-L)(2)](-) subunits grows significantly upon coordination to the Ln atom of the bridging moiety, which consequently induces an increase in the parameter of the axial magnetic anisotropy. This conclusion is obvious from the comparison and analysis of the structural (XRD) and magnetic data of the yttrium trimer 2fand the precursor complex (Pr(3)NH)[Fe(3MeO-L)(2)] (1, Pr(3)NH = the tripropylammonium cation), where D(Fe)(1) = +0.80 cm(-1) and D(Fe)(2f) = +1.64 cm(-1). Furthermore, a weak antiferromagnetic interaction between the Fe(III) centres was found in 2f(J(FeFe) = -0.26 cm(-1)). The magnetic parameters of 2f were used in the fitting of the magnetic properties of 2a as constraints. The ferromagnetic nature of the Fe-Gd interaction in 2a was confirmed, with J(GdFe) = +1.40 cm(-1), D(Gd) = -0.26 cm(-1). Moreover, in the case of the Tb (2b) and Dy (2c) compounds, a slow relaxation of the magnetization at low temperature (below 1.9 K) was observed upon the dehydration of the parent compounds. PMID:23104402

  5. A series of transition and non-transition metal complexes from a N 4O 2 hexadentate Schiff base ligand: Synthesis, spectroscopic characterization and efficient antimicrobial activities

    NASA Astrophysics Data System (ADS)

    Sarkar, Saikat; Dey, Kamalendu

    2010-11-01

    Some transition and non-transition metal complexes of the hexadentate N 4O 2 donor Schiff base ligand 1,8- N-bis(3-carboxy)disalicylidene-3,6-diazaoctane-1,8-diamine, abbreviated to H 4fsatrien, have been synthesized. All the 14 metal complexes have been fully characterized with the help of elemental analyses, molecular weights, molar conductance values, magnetic moments and spectroscopic (UV-Vis, IR, NMR, ESR) data. The analytical data helped to elucidate the structures of the metal complexes. The Schiff base, H 4fsatrien, is found to act as a dibasic hexadentate ligand using N 2N 2O 2 donor set of atoms (leaving the COOH group uncoordinated) leading to an octahedral geometry for the complexes around all the metal ions except VO 2+ and UO 22+. However, surprisingly the same ligand functions as a neutral hexadentate and neutral tetradentate one towards UO 22+ and VO 2+, respectively. In case of divalent metal complexes they have the general formula [M(H 2fsatrien)] (where M stands for Cu, Co, Hg and Zn); for trivalent metal complexes it is [M(H 2fsatrien)]X· nH 2O (where M stands for Cr, Mn, Fe, Co and X stands for CH 3COO, Cl, NO 3, ClO 4) and for the complexes of VO 2+ and UO 22+, [M(H 4fsatrien)]Y (where M = VO and Y = SO 4; M = UO 2 and Y = 2 NO 3). The Schiff base ligand and most of the complexes have been screened in vitro to judge their antibacterial ( Escherichia coli and Staphylococcus aureus) and antifungal ( Aspergillus niger and Pencillium chrysogenum) activities.

  6. Ni(II) and Pd(II) complexes with new N,O donor thiophene appended Schiff base ligand: Synthesis, electrochemistry, X-ray structure and DFT calculation

    NASA Astrophysics Data System (ADS)

    Kundu, Subhankar; Pramanik, Ajoy Kumar; Mondal, Apurba Sau; Mondal, Tapan Kumar

    2016-07-01

    The thiophene appended Schiff's base ligand, 1-(2-(thiophen-2-yl)ethylimino)methyl)naphthalene-2-ol (HL) with N,O donor sites has been synthesized by the condensation between 2-hydroxy-1-naphthaldehyde and thiophene-2-ethylamine. The square planar 1:2 complexes of HL having general formula [M(L)2] (M = Ni(1) and Pd(2)) with nickel(II) and palladium(II) have been synthesized and characterized by several spectroscopic techniques. The geometry has been confirmed by single crystal X-ray study for complex 1. The electronic structure and spectral properties of the complexes are interpreted by DFT and TDDFT studies.

  7. 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 μg/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.

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

    PubMed

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

    2015-04-01

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

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

    PubMed Central

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

    2013-01-01

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

  10. 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.

  11. Synthesis, characterization and crystal structures of the bidentate Schiff base N,N'-bis(2-nitrocinnamaldehyde)ethylenediamine and its complex with CuNCS and triphenylphosphane.

    PubMed

    Clegg, William; Harrington, Ross W; Barati, Kazem; Habibi, Mohammad Hossein; Montazerozohori, Morteza; Lalegani, Arash

    2015-07-01

    Reaction of copper(I) thiocyanate and triphenylphosphane with the bidentate Schiff base N,N'-bis(trans-2-nitrocinnamaldehyde)ethylenediamine {Nca2en, (1); systematic name (1E,1'E,2E,2'E)-N,N'-(ethane-1,2-diyl)bis[3-(2-nitrophenyl)prop-2-en-1-imine]}, C20H18N4O4, in a 1:1:1 molar ratio in acetonitrile resulted in the formation of the complex {(1E,1'E,2E,2'E)-N,N'-(ethane-1,2-diyl)bis[3-(2-nitrophenyl)prop-2-en-1-imine]-κ(2)N,N'}(thiocyanato-κN)(triphenylphosphane-κP)copper(I)], [Cu(NCS)(C20H18N4O4)(C18H15P)] or [Cu(NCS)(Nca2en)(PPh3)], (2). The Schiff base and copper(I) complex have been characterized by elemental analyses, IR, electronic and (1)H NMR spectroscopy, and X-ray crystallography [from synchrotron data for (1)]. The molecule of (1) lies on a crystallographic inversion centre, with a trans conformation for the ethylenediamine unit, and displays significant twists from coplanarity of its nitro group, aromatic ring, conjugated chain and especially ethylenediamine segments. It acts as a bidentate ligand coordinating via the imine N atoms to the Cu(I) atom in complex (2), in which the ethylenediamine unit necessarily adopts a somewhat flattened gauche conformation, resulting in a rather bowed shape overall for the ligand. The NCS(-) ligand is coordinated through its N atom. The geometry around the Cu(I) atom is distorted tetrahedral, with a small N-Cu-N bite angle of 81.56 (12)° and an enlarged opposite angle of 117.29 (9)° for SCN-Cu-P. Comparisons are made with the analogous Schiff base having no nitro substituents and with metal complexes of both ligands.

  12. 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

  13. Experimental and Theoretical Investigations of Magnetic Exchange Pathways in Structurally Diverse Iron(III) Schiff-Base Complexes.

    PubMed

    Herchel, Radovan; Nemec, Ivan; Machata, Marek; Trávníček, Zdeněk

    2015-09-01

    The synthesis, and the structural and magnetic properties, of the following new iron(III) Schiff base complexes with the {O',N,O″}-chelating ligand H2L (2-hydroxyphenylsalicylaldimine) are reported: K[FeL2]·H2O (1), (Pr3NH)[FeL2]·2CH3OH (2), [FeL(bpyO2) (CH3OH)][FeL2]·CH3OH (3), [Fe2L3(CH3OH)]·2CH3OH·H2O (4), and [{Fe2L2}(μ-OH)2{FeL(bpyO2)}2][BPh4]2·2H2O (5), where Pr3NH(+) represents the tripropylammonium cation and bpyO2 stands for 2,2'-bipyridine-N-dioxide. A thorough density functional theory (DFT) study of magnetic interactions (the isotropic exchange) at the B3LYP/def-TZVP level of theory was employed, and calculations have revealed superexchange pathways through intramolecular/intermolecular noncovalent contacts (π-π stacking, C-H···O and O-H···O hydrogen bonds, diamagnetic metal cations) and/or covalent bonds ((μ-O(Ph), μ-OH) or bis(μ-O(Ph)) bridging modes), which helped us to postulate trustworthy spin Hamiltonians for magnetic analysis of experimental data. Within the reported family of compounds 1-5, the mediators of the antiferromagnetic exchange can be sorted by their increasing strength as follows: π-π stacking (J(DFT) = -0.022 cm(-1)/J(mag) = -0.025(4) cm(-1) in 2) < C-H···O contacts and π-π stacking (J(DFT) = -0.19 cm(-1)/J(mag) = -0.347(9)cm(-1) in 1) < O-H···O hydrogen bonds (J(DFT) = -0.53 cm(-1)/J(mag) = -0.41(1) cm(-1) in 3) < bis(μ-O(Ph)) bridge (J(DFT) = -13.8 cm(-1)/J(mag) = -12.3(9) cm(-1) in 4) < (μ-O(Ph), μ-OH) bridge (J(DFT) = -18.0 cm(-1)/J(mag) = -17.1(2) cm(-1) in 5), where J(DFT) and J(mag) are the isotropic exchange parameters derived from DFT calculations, and analysis of the experimental magnetic data, respectively. The good agreement between theoretically calculated and experimentally derived isotropic exchange parameters suggests that this procedure is applicable also for other chemical and structural systems to interpret magnetic data properly. PMID:26262499

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

    PubMed

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

    2013-04-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2013-04-01

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

  17. Exploration of cellular DNA lesion, DNA-binding and biocidal ordeal of novel curcumin based Knoevenagel Schiff base complexes incorporating tryptophan: Synthesis and structural validation

    NASA Astrophysics Data System (ADS)

    Chandrasekar, Thiravidamani; Raman, Natarajan

    2016-07-01

    A few novel Schiff base transition metal complexes of general formula [MLCl] (where, L = Schiff base, obtained by the condensation reaction of Knoevenagel condensate of curcumin, L-tryptophan and M = Cu(II), Ni(II), Co(II), and Zn(II)), were prepared by stencil synthesis. They were typified using UV-vis, IR, EPR spectral techniques, micro analytical techniques, magnetic susceptibility and molar conductivity. Geometry of the metal complexes was examined and recognized as square planar. DNA binding and viscosity studies revealed that the metal(II) complexes powerfully bound via an intercalation mechanism with the calf thymus DNA. Gel-electrophoresis technique was used to investigate the DNA cleavage competence of the complexes and they establish to approve the cleavage of pBR322 DNA in presence of oxidant H2O2. This outcome inferred that the synthesized complexes showed better nuclease activity. Moreover, the complexes were monitored for antimicrobial activities. The results exposed that the synthesized compounds were forceful against all the microbes under exploration.

  18. 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.

  19. DNA cleavage, antimicrobial, spectroscopic and fluorescence studies of Co(II), Ni(II) and Cu(II) complexes with SNO donor coumarin Schiff bases

    NASA Astrophysics Data System (ADS)

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

    2010-01-01

    A series of Co(II), Ni(II) and Cu(II) complexes of the type ML 2 have been synthesized with Schiff bases derived from methylthiosemicarbazone and 5-formyl-6-hydroxy coumarin/8-formyl-7-Hydroxy-4-methylcoumarin. The complexes are insoluble in common organic solvents but soluble in DMF and DMSO. The measured molar conductance values in DMF indicate that, the complexes are non-electrolytes in nature. In view of analytical, spectral (IR, UV-vis, ESR, FAB-mass and fluorescence), magnetic and thermal studies, it has been concluded that, all the metal complexes possess octahedral geometry in which ligand is coordinated to metal ion through azomethine nitrogen, thione sulphur and phenolic oxygen atom via deprotonation. The redox behavior of the metal complexes was investigated by using cyclic voltammetry. The Schiff bases and their complexes have been screened for their antibacterial ( Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa and Salmonella typhi) and antifungal activities ( Aspergillus niger, Aspergillus flavus and Cladosporium) by Minimum Inhibitory Concentration method. The DNA cleavage is studied by agarose gel electrophoresis method.

  20. Low-cost chemiresistive sensor for volatile amines based on a 2D network of a zinc(II) Schiff-base complex

    NASA Astrophysics Data System (ADS)

    Mirabella, S.; Oliveri, I. P.; Ruffino, F.; Maccarrone, G.; Di Bella, S.

    2016-10-01

    A marked chemiresistive behavior is revealed in a nanostructured material obtained by spin-coating a solution of a bis(salycilaldiminato)Zn(II) Schiff-base (ZnSB) complex. The resulting submicron 2D network exhibits reversible changes in absorbance and resistance under the cycles of absorption and desorption of a volatile amine. These results are explained in terms of a Lewis donor-acceptor interaction between the ZnSB (acceptor) and the chemisorbed amine (donor). The 2D network of ZnSB was employed as a sensing element to fabricate a low-cost device for the volatile amines detection, showing promising results for food spoilage detection.

  1. Binuclear Zn(II)–Zn(II) Complex from a 2-Hydroxybenzohydrazide-Derived Schiff Base for Selective Detection of Pyrophosphate

    PubMed Central

    Wang, Junfeng; Liu, Bin; Liu, Xiumin; Panzner, Matt; Wesdemiotis, Chrys

    2014-01-01

    A hydroxybenzohydrazide-based Schiff base ligand was conveniently synthesized. Upon addition of Zn2+ cation, the ligand exhibited a high tendency to form a binuclear structure with a 2:2 ligand-to-zinc ratio, which was accompanied with a large fluorescence turn-on (λem = 507 nm, ϕfl ≈ 0.28). The reactivity of zinc complex was examined by using different phosphate anions, which reveals a higher response to acid pyrophosphate anion. Detailed spectroscopic studies revealed that the pyrophosphate response is based on the ligand displacement mechanism. PMID:25135613

  2. 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

  3. 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.

  4. Structural, spectral and biological studies of binuclear tetradentate metal complexes of N3O Schiff base ligand synthesized from 4,6-diacetylresorcinol and diethylenetriamine.

    PubMed

    Emara, Adel A A

    2010-09-15

    The binuclear Schiff base, H2L, ligand was synthesized by reaction of 4,6-diacetylresorcinol with diethylenetriamine in the molar ratio 1:2. The coordination behavior of the H2L towards Cu(II), Ni(II), Co(II), Zn(II), Fe(III), Cr(III), VO(IV) and UO2(VI) ions has been investigated. The elemental analyses, magnetic moments, thermal studies and IR, electronic, 1H NMR, ESR and mass spectra were used to characterize the isolated ligand and its metal complexes. The ligand acts as dibasic with two N3O-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. PMID:20627808

  5. 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∗, ΔH∗, ΔG∗ and ΔS∗ 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.

  6. Synthesis, spectral characterization, molecular modeling, biological activity and potentiometric studies of 4-amino-5-mercapto-3-methyl-S-triazole Schiff's base complexes

    NASA Astrophysics Data System (ADS)

    Alaghaz, Abdel-Nasser M. A.; Zayed, Mohamed E.; Alharbi, Suliman A.

    2015-03-01

    The Schiff's base derived from condensation of s-triazole (4-amino-5-mercapto-3-methyl-S-triazole) with pyridine-2-aldehyde and their corresponding Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) complexes have been synthesized. The isolated solid complexes were characterized by elemental analyses, molar conductance, spectral (IR, UV-Vis, 1H NMR, mass), magnetic moment and thermal measurements. The IR spectral data suggest that the ligand coordinate in a tridentate manner (SNN) via the one thiol (SH), one pyridine ring and the azomethine (Cdbnd N) groups. The data show that the complexes have composition of ML2 type. The activation of thermodynamic parameters are calculated using Coats-Redfern, Horowitz-Metzger (HM), and Piloyan-Novikova (PN). The octahedral geometry of the complexes is confirmed using DFT method from DMOL3 calculations and ligand field parameters. Protonation constants of Schiff base and stability constants of their binary metal complexes have been determined potentiometrically in 50% DMSO-water media at 25 °C and ionic strength 0.10 M potassium nitrate. The biological activity of these compounds against various fungi has been investigated.

  7. Spectral characterization of novel ternary zinc(II) complexes containing 1,10-phenanthroline and Schiff bases derived from amino acids and salicylaldehyde-5-sulfonates

    NASA Astrophysics Data System (ADS)

    Boghaei, Davar M.; Gharagozlou, Mehrnaz

    2007-07-01

    A series of new ternary zinc(II) complexes [Zn(L 1-10)(phen)], where phen is 1,10-phenanthroline and H 2L 1-10 = tridentate Schiff base ligands derived from the condensation of amino acids (glycine, L-phenylalanine, L-valine, L-alanine, and L-leucine) and salicylaldehyde-5-sulfonates (sodium salicylaldehyde-5-sulfonate and sodium 3-methoxy-salicylaldehyde-5-sulfonate), have been synthesized. The complexes were characterized by elemental analysis, IR, UV-vis, 1H NMR, and 13C NMR spectra. The IR spectra of the complexes showed large differences between νas(COO) and νs(COO), Δ ν ( νas(COO) - νs(COO)) of 191-225 cm -1, indicating a monodentate coordination of the carboxylate group. Spectral data showed that in these ternary complexes the zinc atom is coordinated with the Schiff base ligand acts as a tridentate ONO moiety, coordinating to the metal through its phenolic oxygen, imine nitrogen, and carboxyl oxygen, and also with the neutral planar chelating ligand, 1,10-phenanthroline, coordinating through nitrogens.

  8. Spectroscopic and biological activities studies of bivalent transition metal complexes of Schiff bases derived from condensation of 1,4-phenylenediamine and benzopyrone derivatives.

    PubMed

    Sherif, Omaima E; Abdel-Kader, Nora S

    2014-01-01

    Many tools of analysis such as elemental analyses, infrared, ultraviolet-visible, electron spin resonance (ESR) and thermal analysis, as well as conductivity and magnetic susceptibility measurements were used to elucidate the structures of the newly prepared Co(II), Ni(II) and Cu(II) complexes with Schiff bases derived from the condensation of 1,4-phenylenediamine with 6-formyl-7-hydroxy-5-methoxy-2-methylbenzo-pyran-4-one (H2L) or 5,7-dihydroxy-6-formyl-2-methylbenzopyran-4-one (H4L). The data showed that all formed complexes are 1:1 or 2:2 (M:L) and non-electrolyte chelates. The Co(II) and Cu(II) complexes of the two Schiff bases were screened for antibacterial activities by the disk diffusion method. The antibacterial activity was screened using Escherichia coli and Staphylococcus capitis but the antifungal activity was examined by using Aspergillus flavus and Candida albicans. The Results showed that the tested complexes have antibacterial, except CuH4L, but not antifungal activities.

  9. A Schiff base-derived copper (II) complex is a potent inducer of apoptosis in colon cancer cells by activating the intrinsic pathway.

    PubMed

    Hajrezaie, Maryam; Paydar, Mohammadjavad; Moghadamtousi, Soheil Zorofchian; 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  μg/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  μg/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.

  10. Spectroscopic and biological activities studies of bivalent transition metal complexes of Schiff bases derived from condensation of 1,4-phenylenediamine and benzopyrone derivatives

    NASA Astrophysics Data System (ADS)

    Sherif, Omaima E.; Abdel-Kader, Nora S.

    2014-01-01

    Many tools of analysis such as elemental analyses, infrared, ultraviolet-visible, electron spin resonance (ESR) and thermal analysis, as well as conductivity and magnetic susceptibility measurements were used to elucidate the structures of the newly prepared Co(II), Ni(II) and Cu(II) complexes with Schiff bases derived from the condensation of 1,4-phenylenediamine with 6-formyl-7-hydroxy-5-methoxy-2-methylbenzo-pyran-4-one (H2L) or 5,7-dihydroxy-6-formyl-2-methylbenzopyran-4-one (H4L). The data showed that all formed complexes are 1:1 or 2:2 (M:L) and non-electrolyte chelates. The Co(II) and Cu(II) complexes of the two Schiff bases were screened for antibacterial activities by the disk diffusion method. The antibacterial activity was screened using Escherichia coli and Staphylococcus capitis but the antifungal activity was examined by using Aspergillus flavus and Candida albicans. The Results showed that the tested complexes have antibacterial, except Cusbnd H4L, but not antifungal activities.

  11. 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 μg/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 μg/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

  12. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2015-02-01

    An unexpected Schiff base-type Ni(II) complex, [Ni(L2)2]ṡCH3OH (HL2 = 1-(2-{[(E)-3, 5-dibromo-2-hydroxybenzylidene]amino}phenyl)ethanone oxime), has been synthesized via complexation of Ni(II) acetate tetrahydrate with HL1 (2-(3,5-dibromo-2-hydroxyphenyl)-4-methyl-1,2-dihydroquinazoline 3-oxide) originally. HL1 and its corresponding Ni(II) complex were characterized by IR, 1H 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 HL1 and Ni(II) complex were also investigated.

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

    PubMed Central

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

    2007-01-01

    Objective: A series of 2-benzylideneaminonaphthothiazoles were designed and synthesized incorporating the lipophilic naphthalene ring to render them more capable of penetrating various biomembranes. Methods: Schiff bases were synthesized by the reaction of naphtha[1,2-d]thiazol-2-amine with various substituted aromatic aldehydes. 2-(2′-Hydroxy)benzylideneaminonaphthothiazole was converted to its Co(II), Ni(II) and Cu(II) metal complexes upon treatment with metal salts in ethanol. All the compounds were evaluated for their antibacterial activities by paper disc diffusion method with Gram positive Staphylococcus aureus and Staphylococcus epidermidis and Gram negative Escherichia coli and Pseudomonas aeruginosa bacteria. The minimum inhibitory concentrations of all the Schiff bases and metal complexes were determined by agar streak dilution method. Results: All the compounds moderately inhibited the growth of Gram positive and Gram negative bacteria. In the present study among all Schiff bases 2-(2′-hydroxy)benzylideneaminonaphthothiazole showed maximum inhibitory activity and among metal complexes Cu(II) metal complex was found to be most potent. Conclusion: The results obtained validate the hypothesis that Schiff bases having substitution with halogens, hydroxyl group and nitro group at phenyl ring are required for the antibacterial activity while methoxy group at different positions in the aromatic ring has minimal role in the inhibitory activity. The results also indicated that the metal complexes are better antibacterial agents as compared to the Schiff bases. PMID:17565517

  15. 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

  16. Properties of Asp212----Asn bacteriorhodopsin suggest that Asp212 and Asp85 both participate in a counterion and proton acceptor complex near the Schiff base

    SciTech Connect

    Needleman, R.; Chang, M.; Ni, B.; Varo, G.; Fornes, J.; White, S.H.; Lanyi, J.K. )

    1991-06-25

    The gene coding for bacteriorhodopsin was modified in vitro to replace Asp212 with asparagine and expressed in Halobacterium halobium. x-ray diffraction measurements showed that the major lattice dimension of purple membrane containing the mutated bacteriorhodopsin was the same as wild type. At pH greater than 7, the Asp212----Asn chromophore was blue (absorption maximum at 585 nm) and exhibited a photocycle containing only the intermediates K and L, i.e. a reaction sequence very similar to that of wild-type bacteriorhodopsin at pH less than 3 and the blue form of the Asp85----Glu protein at pH less than 9. Since in the latter cases these effects are attributed to protonation of residue 85, it now appears that removal of the carboxylate of Asp212 has similar consequences as removing the carboxylate of Asp85. However, an important difference is that only Asp85 affects the pKa of the Schiff base. At pH less than 7, the Asp212----Asn protein was purple (absorption maximum at 569 nm) but photoexcitation produced only 15% of the normal amount of M and the transport activity was partial. The reactions of the blue and purple forms after photoexcitation are both quantitatively accounted for by a proposed scheme, K in equilibrium with L1 in equilibrium with L2----BR, but with the addition of an L1 in equilibrium with M reaction with unfavorable pKa for Schiff base deprotonation in the purple form. The latter hinders the transient accumulation of M, and the consequent branching at L1 allows only partial proton transport activity. The results are consistent with the existence of a complex counterion for the Schiff base proposed earlier and suggest that Asp85, Asp212, and at least one other protonable residue participate in it.

  17. 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.

  18. 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

  19. Synthesis, spectroscopy and biological investigations of manganese(III) Schiff base complexes derived from heterocyclic β-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 Δ S*, enthalpy change Δ 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.

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

    NASA Astrophysics Data System (ADS)

    Salavati-Niasari, Masoud; Bazarganipour, Mehdi

    2008-12-01

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

  1. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2008-11-01

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

  3. Spin Crossover Properties of Iron(ii) Complexes with a N4O2 Donor Set by Extended Π-CONJUGATED Schiff-Base Ligands

    NASA Astrophysics Data System (ADS)

    Kuroda, Takayoshi

    2013-09-01

    The preparation and magnetic properties of three Fe(II) Schiff-base complexes, [Fe(qnal-21)2]•CH2Cl2 (1), [Fe(qnal-12)2]•2C6H6 (2) and [Fe(Hqsalc)2] (3), (Hqnal-21 = N-(8'-quinolyl)-2-hydroxy-1-naphthaldimine, Hqnal-12 = N-(8'-quinolyl)-1-hydroxy-2-naphthaldimine, H2qsalc = 4-hydroxy-3-[(8-quinolinylimino)methyl]benzoic acid) are reported. X-ray single crystal structure analyses of 1 and 2 reveal that an Fe(II) ion in each complex is coordinated by two Schiff-base ligands, qnal-21 or qnal-12, in a meridional fashion. Molecular packing of 2 shows that a qnal-12 interacts with neighboring two qnal-12's through π-π interactions, which results in the formation of one-dimensional chain. Although the magnetic property of 2 shows a high-spin state at all the temperature range measured, the χT-T plot of 3 shows abrupt spin crossover behavior with a wide hysteresis of 21 K, probably due to the hydrogen-bond network originated by carboxyl groups.

  4. 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, Δ 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.

  5. Synthesis, crystal structure, spectral characterization and photoluminescence property of three Cd(II) complexes with a pyrazole based Schiff-base ligand

    NASA Astrophysics Data System (ADS)

    Mandal, Susmita; Saha, Rajat; Saha, Manan; Pradhan, Rajesh; Butcher, Ray J.; Saha, Nitis Chandra

    2016-04-01

    Substituted pyrazole containing Schiff-base ligand, 5-methyl-3-formylpyrazole-N-(2‧-methylphenoxy)methyleneimine, (MPzOA), afforded three new Cd(II) complexes, [Cd(MPzOA)Cl2]2.CH3OH (I), [Cd(MPzOA)2(H2O)2](ClO4)2 (II) and [Cd(MPzOA)(H2O)(NO3)2] (III). In the reported complex species the coordination number and geometry of Cd(II) vary. In complex I and II, Cd(II) adopts six and in (III) it adopts eight coordination modes, with prismatic, octahedral and distorted dodecahedral geometry, respectively. All the complexes are characterized by IR, 1H NMR, UV-Vis spectral parameters and X-ray analyses. The complexes have 1D, 2D and 3D supramolecular frameworks formed by non-covalent interactions, like hydrogen bonding, π … π stacking, C-H … π interactions.

  6. Synthesis, characterization of α-amino acid Schiff base derived Ru/Pt complexes: Induces cytotoxicity in HepG2 cell via protein binding and ROS generation

    NASA Astrophysics Data System (ADS)

    Alsalme, Ali; Laeeq, Sameen; Dwivedi, Sourabh; Khan, Mohd. Shahnawaz; Al Farhan, Khalid; Musarrat, Javed; Khan, Rais Ahmad

    2016-06-01

    We have synthesized two new complexes of platinum (1) and ruthenium (2) with α-amino acid, L-alanine, and 2,3-dihydroxybenzaldehyde derived Schiff base (L). The ligand and both complexes were characterized by using elemental analysis and several other spectroscopic techniques viz; IR, 1H, 13C NMR, EPR, and ESI-MS. Furthermore, the protein-binding ability of synthesized complexes was monitored by UV-visible, fluorescence and circular dichroism techniques with a model protein, human serum albumin (HSA). Both the PtL2 and RuL2 complexes displayed significant binding towards HSA. Also, in vitro cytotoxicity assay for both complexes was carried out on human hepatocellular carcinoma cancer (HepG2) cell line. The results showed concentration-dependent inhibition of cell viability. Moreover, the generation of reactive oxygen species was also evaluated, and results exhibited substantial role in cytotoxicity.

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

    PubMed Central

    Rauf, Abdur

    1996-01-01

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

  8. Synthesis, spectroscopic characterization and antimicrobial activity of mono-, bi- and tri-nuclear metal complexes of a new Schiff base ligand

    NASA Astrophysics Data System (ADS)

    Shebl, Magdy; Khalil, Saied M. E.; Ahmed, Saleh A.; Medien, Hesham A. A.

    2010-09-01

    Condensation of o-acetoacetylphenol and 1,2-diaminopropane in 1:1 molar ratio under condition of high dilution yielded the mono-condensed dibasic Schiff base ligand with a N 2O 2 donors. The mono-condensed ligand has been used for further condensation with 2-hydroxy-5-nitrobenzaldehyde to obtain the new asymmetrical dicompartmental Schiff base ligand, H 3L, with N 2O 3 donors. The structure of the ligand was elucidated by analytical and spectroscopic tools (IR, 1H and 13C NMR spectra) which indicated that the coordinating sites are oxygen atoms of the phenolic OH groups, nitrogen atoms of the azomethine groups and the oxygen atom of the ketonic group. Reactions of the ligand with metal salts yielded mono- and homo-bi-nuclear complexes formulated as [M(HL)], where M dbnd Co(II), Ni(II) and Cu(II), [Fe(H 2L)Cl 2(H 2O)]ṡ2½H 2O, [Fe 2(HL)(ox)Cl 3(H 2O) 2]ṡ5H 2O, [UO 2(H 2L)(OAc)(H 2O) 2], [VO(H 3L)(SO 4)(H 2O)]ṡH 2O, [M 2(L)Cl(H 2O) 2]ṡ½H 2O, where M dbnd Co(II) and Ni(II) and [Cu(H 2L)Cl]. The mononuclear Ni(II) complex, [Ni(HL)], was used to synthesize homo- and hetero-bi- and tri-nuclear complexes with the molecular formulae [Ni 2(L)Cl(H 2O) 2], [Ni 2(L) 2FeCl(H 2O)]ṡH 2O and [Ni 2(HL) 2CoCl 2]. The structures of the complexes were characterized by various techniques such as elemental and thermal analyses, IR, 1H and 13C NMR, mass and electronic spectra as well as conductivity and magnetic moment measurements. Square-planar and octahedral geometries are suggested for the Cu(II), Co(II) and Ni(II) complexes, octahedral geometry for the Fe(III) and VO 2+ complexes while uranium(VI) ion is octa-coordinated in its complex. 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.

  9. Cu(II), Ni(II) complexes derived from chiral Schiff-base ligands: Synthesis, characterization, cytotoxicity, protein and DNA-binding properties.

    PubMed

    Li, Zhen; Yan, Hui; Chang, Guoliang; Hong, Min; Dou, Jianmin; Niu, Meiju

    2016-10-01

    A series of novel copper (II) and nickel (II) complexes derived from chiral Schiff-base ligands [(R)/(S)-H2L(1)=(R)/(S)-2-[(1-Hydroxymethyl-propylimino)-methyl]-5-methoxy-phenol and (R)/(S)-H2L(2)=(R)/(S)-2-[(1-Hydroxymethyl-2-phenyl-ethylimino)-methyl]-5-methoxy-phenol], were synthesized and characterized by elemental analyses, (1)H NMR spectra, FT-IR spectrum. The crystal structures of complexes 1-5 were determined through single crystal X-ray diffraction (SXRD). The structures showed the ligands coordinated to the Cu/Ni (II) ion in a neutral manner via ONO donor atoms, and oxygen atoms of solvent molecules occupy the axial positions in Ni (II) complexes 3 and 4. The complexes interactions with BSA and CT-DNA were investigated by various spectroscopic methods (UV-Visible, circular dichroism spectrum, fluorescence spectroscopic and synchronous fluorescence spectra). Interactions of chiral copper (II) complexes are stronger than nickel (II) complexes. Further, the cytotoxicities of the complexes 1-6 towards three kinds of cancerous cell lines, were human lung adenocarcinoma (A549), human cervical carcinoma cell (HeLa) and human breast cancer cell (MCF-7) respectively, were evaluated by MTT assay. All complexes exhibited good cytotoxic activity. Furthermore, Cu (II) complex 5 derived from (R)-Schiff-base ligand was found to be more effective towards HeLa cancerous cell. The results showed that chirality and metal ion have important influence on their anticancer activities and interactions with DNA/BSA.

  10. Cu(II), Ni(II) complexes derived from chiral Schiff-base ligands: Synthesis, characterization, cytotoxicity, protein and DNA-binding properties.

    PubMed

    Li, Zhen; Yan, Hui; Chang, Guoliang; Hong, Min; Dou, Jianmin; Niu, Meiju

    2016-10-01

    A series of novel copper (II) and nickel (II) complexes derived from chiral Schiff-base ligands [(R)/(S)-H2L(1)=(R)/(S)-2-[(1-Hydroxymethyl-propylimino)-methyl]-5-methoxy-phenol and (R)/(S)-H2L(2)=(R)/(S)-2-[(1-Hydroxymethyl-2-phenyl-ethylimino)-methyl]-5-methoxy-phenol], were synthesized and characterized by elemental analyses, (1)H NMR spectra, FT-IR spectrum. The crystal structures of complexes 1-5 were determined through single crystal X-ray diffraction (SXRD). The structures showed the ligands coordinated to the Cu/Ni (II) ion in a neutral manner via ONO donor atoms, and oxygen atoms of solvent molecules occupy the axial positions in Ni (II) complexes 3 and 4. The complexes interactions with BSA and CT-DNA were investigated by various spectroscopic methods (UV-Visible, circular dichroism spectrum, fluorescence spectroscopic and synchronous fluorescence spectra). Interactions of chiral copper (II) complexes are stronger than nickel (II) complexes. Further, the cytotoxicities of the complexes 1-6 towards three kinds of cancerous cell lines, were human lung adenocarcinoma (A549), human cervical carcinoma cell (HeLa) and human breast cancer cell (MCF-7) respectively, were evaluated by MTT assay. All complexes exhibited good cytotoxic activity. Furthermore, Cu (II) complex 5 derived from (R)-Schiff-base ligand was found to be more effective towards HeLa cancerous cell. The results showed that chirality and metal ion have important influence on their anticancer activities and interactions with DNA/BSA. PMID:27619741

  11. Synthesis, spectroscopic characterization and magnetic properties of homo- and heterodinuclear complexes of transition and non-transition metal ions with a new Schiff base ligand

    NASA Astrophysics Data System (ADS)

    Sarkar, Saikat; Biswas, Susobhan; Dey, Kamalendu

    2008-12-01

    Four homodinuclear complexes of Ni(II)-Ni(II), Cu(II)-Cu(II), Co(II)-Co(II) and Co(III)-Co(II) and five heterodinuclear complexes of Co(III)-Zn(II), Co(III)-Cu(II), Co(III)-Ni(II), Cu(II)-Zn(II) and Zn(II)-Cu(II) with the octadentate Schiff base compartmental ligand 1,8- N-bis(3-carboxy)disalicylidene-3,6-diazaoctane-1,8-diamine (H 4fsatrien) have been synthesized. The complexes have been characterized with the help of elemental analyses, molecular weights, molar conductances, magnetic susceptibilities and spectroscopic (UV-vis, IR, ESR) data. Cryomagnetic data also helped to elucidate the structural features of the Cu(II) complexes.

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

    PubMed

    Mohammadi, Khosro; Niad, Mahmood; Irandoost, Amene

    2013-04-15

    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 (L(1)), 3,4-bis-((E)-2-hydroxy-3-methoxybenzylideneamino)benzoic acid (L(2)) and 3,4-bis((E)-2,4-dihydroxybenzylideneamino)benzoic acid (L(3)) 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 VOL(3)>VOL(1)>VOL(2). 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: VOL(3)>VOL(2)>VOL(1).

  13. 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.

  14. Nano structure zinc (II) Schiff base complexes of a N3-tridentate ligand as new biological active agents: spectral, thermal behaviors and crystal structure of zinc azide complex.

    PubMed

    Montazerozohori, M; Mojahedi Jahromi, S; Masoudiasl, A; McArdle, P

    2015-03-01

    In this work, synthesis of some new five coordinated zinc halide/pseudo-halide complexes of a N3-tridentate ligand is presented. All complexes were subjected to spectroscopic and physical methods such as FT-IR, UV-visible, (1)H and (13)C NMR spectra, thermal analyses and conductivity measurements for identification. Based on spectral data, the general formula of ZnLX2 (X=Cl(-), Br(-), I(-), SCN(-) and N3(-)) was proposed for the zinc complexes. Zinc complexes have been also prepared in nano-structure sizes under ultrasonic irradiation. X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were applied for confirmation of nano-structure character for the complexes. Among the complexes, zinc azide complex structure was analyzed by X-ray crystallography. This complex crystallizes as a triplet in trigonal system with space group of P31. The coordination sphere around the zinc center is well shown as a distorted trigonal bipyramidal with three nitrogen atoms from Schiff base ligand and two terminal azide nitrogen atoms attached to zinc ion. Various intermolecular interactions such as NH⋯N, CH⋯N and CH⋯π hydrogen bonding interactions stabilize crystalline lattice so that they causes a three dimensional supramolecular structure for the complex. In vitro screening of the compounds for their antimicrobial activities showed that ZnLI2, ZnL(N3)2, ZnLCl2 and ZnL(NCS)2 were found as the most effective compound against bacteria of Bacillus subtilis, Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli respectively. Also ZnLI2 and ZnLCl2 complexes were found more effective against two selected fungi than others. Finally, thermal behaviors of the zinc complexes showed that they are decomposed via 2-4 thermal steps from room temperature up to 1000°C. PMID:25528511

  15. Nano structure zinc (II) Schiff base complexes of a N3-tridentate ligand as new biological active agents: Spectral, thermal behaviors and crystal structure of zinc azide complex

    NASA Astrophysics Data System (ADS)

    Montazerozohori, M.; Mojahedi Jahromi, S.; Masoudiasl, A.; McArdle, P.

    2015-03-01

    In this work, synthesis of some new five coordinated zinc halide/pseudo-halide complexes of a N3-tridentate ligand is presented. All complexes were subjected to spectroscopic and physical methods such as FT-IR, UV-visible, 1H and 13C NMR spectra, thermal analyses and conductivity measurements for identification. Based on spectral data, the general formula of ZnLX2 (X = Cl-, Br-, I-, SCN- and N3-) was proposed for the zinc complexes. Zinc complexes have been also prepared in nano-structure sizes under ultrasonic irradiation. X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were applied for confirmation of nano-structure character for the complexes. Among the complexes, zinc azide complex structure was analyzed by X-ray crystallography. This complex crystallizes as a triplet in trigonal system with space group of P31. The coordination sphere around the zinc center is well shown as a distorted trigonal bipyramidal with three nitrogen atoms from Schiff base ligand and two terminal azide nitrogen atoms attached to zinc ion. Various intermolecular interactions such as Nsbnd H⋯N, Csbnd H⋯N and Csbnd H⋯π hydrogen bonding interactions stabilize crystalline lattice so that they causes a three dimensional supramolecular structure for the complex. In vitro screening of the compounds for their antimicrobial activities showed that ZnLI2, ZnL(N3)2, ZnLCl2 and ZnL(NCS)2 were found as the most effective compound against bacteria of Bacillus subtilis, Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli respectively. Also ZnLI2 and ZnLCl2 complexes were found more effective against two selected fungi than others. Finally, thermal behaviors of the zinc complexes showed that they are decomposed via 2-4 thermal steps from room temperature up to 1000 °C.

  16. A novel Schiff base derived from the gabapentin drug and copper (II) complex: Synthesis, characterization, interaction with DNA/protein and cytotoxic activity.

    PubMed

    Shokohi-Pour, Zahra; Chiniforoshan, Hossein; Momtazi-Borojeni, Amir Abbas; Notash, Behrouz

    2016-09-01

    A novel Schiff base [C20H23NO3], has been prepared and characterized using FT-IR, UV-vis, (1)H NMR spectroscopy, elemental analysis and X-ray crystallography. A copper (II) complex [Cu(C20H22NO3)2]·H2O has also been synthesized and characterized. The new ligand and complex thus obtained were investigated by their interaction with calf thymus DNA and BSA using electronic absorption spectroscopy, fluorescence spectroscopy, and thermal denaturation. The intrinsic binding constants Kb of the ligand and Cu (II) complex, with CT-DNA obtained from UV-vis absorption studies were 1.53×10(4)M(-1) and 3.71×10(5)M(-1), respectively. Moreover the addition of the two compounds to CT-DNA (1:2) led to an increase of the melting temperature of DNA up to around 2.61°C for the ligand and 3.99°C for the Cu (II) complex. The ligand and Cu (II) complex bind to CT-DNA via a partial intercalative, as shown by the experimental data. In addition, the albumin interactions of the two compounds were studied by fluorescence quenching spectra, the results indicating that the binding mechanism is a static quenching process. The in vitro cytotoxicity of the two compounds on three different cancer cell lines was evaluated by MTT assay. The results showed that the copper complex exerted enhanced cytotoxicity compared with the Schiff base ligand; thereby, this complex clearly implies a positive synergistic effect. Furthermore, the copper complex showed a high, selective, and dose-dependent cytotoxicity against cancer cell lines.

  17. Synthesis and spectroscopic characterization of some transition metal complexes of a new hexadentate N(2)S(2)O(2) Schiff base ligand.

    PubMed

    Sarkar, Saikat; Dey, Kamalendu

    2005-11-01

    A novel interesting hexadentate dibasic N(2)S(2)O(2) donor Schiff base ligand, H(4)dcsalpte, was synthesized by the condensation of 3-formylsalicylic acid and 1,2-di(o-aminophenylthio)ethane and characterized. The reactions of the ligand with different metal(II/III)salts under varied reaction conditions afforded a series of metal complexes. The ligand, H(4)dcsalpte, behaves either as a dibasic or neutral hexadentate one, depending on the reaction conditions. Structural investigations on the ligand and their complexes have been made based on elemental analyses, molar conductance values, magnetic moment values, cryomagnetic and spectral (UV-vis, IR, (1)H NMR, and Mössbauer) data. Based on magnetic susceptibility, Mössbauer and electronic spectral data the iron(III) complex [Fe(III)(H(2)dcsalpte)]ClO(4) (8), isolated in the present investigation, it is inferred that the spin states 5/2 and 1/2 are in equilibrium. Similarly a tri-iron(III) complex [Fe(III)(3)(H(2)dcsalpte)(H(3)dcsalpte)Cl(3)]Cl(3) (7), isolated in this study, has been inferred to contain two iron(III) sites in tetrahedral environment and one in the octahedral environment. The aerial oxidation of an equimolar mixture of H(4)dcsalpte and Co(CH(3)COO)(2).4H(2)O in ethanol under reflux gave two products, [Co(H(2)dcsalpte)]CH(3)COO (10) and [(Hbtcsaldm)Co(Hbvcsaldm)] (11), a cobalt(III) complex bound to two dissimilar tridentate NSO donor ligands formed as a result of the oxidative cleavage of the CS bond. In the complex 11, Hbtcsaldm stands for the dianion of the tridentate Schiff base ligand N-(2'-benzenethiol)-3-carboxysalicylaldimine and Hbvcsaldm stands for the mono anion of the tridentate Schiff base ligand N-(benzene-2'-S-vinyl)-3-carboxysalicylaldimine, both being formed as a result of the oxidative cleavage of H(4)dcsalpte. PMID:16257739

  18. Synthesis and spectroscopic characterization of some transition metal complexes of a new hexadentate N 2S 2O 2 Schiff base ligand

    NASA Astrophysics Data System (ADS)

    Sarkar, Saikat; Dey, Kamalendu

    2005-11-01

    A novel interesting hexadentate dibasic N 2S 2O 2 donor Schiff base ligand, H4dcsalpte, was synthesized by the condensation of 3-formylsalicylic acid and 1,2-di( o-aminophenylthio)ethane and characterized. The reactions of the ligand with different metal(II/III)salts under varied reaction conditions afforded a series of metal complexes. The ligand, H4dcsalpte, behaves either as a dibasic or neutral hexadentate one, depending on the reaction conditions. Structural investigations on the ligand and their complexes have been made based on elemental analyses, molar conductance values, magnetic moment values, cryomagnetic and spectral (UV-vis, IR, 1H NMR, and Mössbauer) data. Based on magnetic susceptibility, Mössbauer and electronic spectral data the iron(III) complex [Fe III( H2dcsalpte)]ClO 4 ( 8), isolated in the present investigation, it is inferred that the spin states 5/2 and 1/2 are in equilibrium. Similarly a tri-iron(III) complex [Fe III3( H2dcsalpte)( H3dcsalpte)Cl 3]Cl 3 ( 7), isolated in this study, has been inferred to contain two iron(III) sites in tetrahedral environment and one in the octahedral environment. The aerial oxidation of an equimolar mixture of H4dcsalpte and Co(CH 3COO) 2·4H 2O in ethanol under reflux gave two products, [Co( H2dcsalpte)]CH 3COO ( 10) and [( Hbtcsaldm)Co( Hbvcsaldm)] ( 11), a cobalt(III) complex bound to two dissimilar tridentate NSO donor ligands formed as a result of the oxidative cleavage of the C sbnd S bond. In the complex 11, Hbtcsaldm stands for the dianion of the tridentate Schiff base ligand N-(2'-benzenethiol)-3-carboxysalicylaldimine and Hbvcsaldm stands for the mono anion of the tridentate Schiff base ligand N-(benzene-2'-S-vinyl)-3-carboxysalicylaldimine, both being formed as a result of the oxidative cleavage of H4dcsalpte.

  19. Two new copper(II) complexes with the shortest (N N) diazine based rigid ligand: Example of unusual tridentate coordination mode

    NASA Astrophysics Data System (ADS)

    Karmakar, Ruma; Choudhury, Chirantan Roy; Batten, Stuart R.; Mitra, Samiran

    2007-01-01

    Two new five coordinated Cu(II) complexes, Cu(L)Cl 2,CH 3OH ( 1) and Cu(L)Br 2 ( 2) derived from the flexidentate ligand (L), 2-pyridinealdazine, have been synthesised and characterised by spectroscopic and electrochemical studies. Single crystal structures of the complexes were determined. Crystal structures of both the complexes contain monomeric entities of five coordinated copper(II) ions where the Schiff base ligand, 2-pyridinealdazine, acts in a tridentate fashion. The central part of the ligand in complex 2 is disordered over two positions: N8 sbnd N9 make up the major position and N8A sbnd N9A make up the minor position.

  20. A vanadyl Schiff base complex: {2,2'-[1,1'-(o-phenylenedinitrilo)bis(ethan-1-yl-1-ylidene)]diphenolato}oxovanadium(IV).

    PubMed

    Kurzak, Krzysztof; Ejsmont, Krzysztof; Koprek, Katarzyna

    2011-09-01

    The green crystals of the title compound, [V(C(22)H(18)N(2)O(2))O], represent a mononuclear oxovanadium complex. The central V(IV) centre has a distorted square-pyramidal coordination. Two N atoms and two O atoms of the Schiff base ligand define the base of the pyramid, and the oxide O atom is in the apical position. Density functional theory (DFT) calculations were performed to analyse the changes in the geometry of the ligand during the complex formation. The most significant changes are observed in the values of the torsion angles in the vicinity of the donor N atoms. The HOMA index (Harmonic Oscillator Model of Aromaticity) has been calculated to compare the aromaticity of the benzene rings in the complex and its ligand. PMID:21881172

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

    PubMed

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

    2014-11-11

    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.

  2. 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.

  3. 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.

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

    PubMed

    Mukherjee, Nandini; Podder, Santosh; Banerjee, Samya; Majumdar, Shamik; Nandi, Dipankar; Chakravarty, Akhil R

    2016-10-21

    Copper(II) pyridoxal Schiff base complexes [Cu(L(1)/L(2))(B)]ClO4 (1-4), where HL(1) is 4-(((2-(1H-imidazol-4-yl)ethyl)imino)methyl)-5-(hydroxymethyl)-2-methylpyridin-3-ol (in 1 and 2), HL(2) is 2-(((2-(1H-imidazol-4-yl)ethyl)imino)methyl)phenol (in 3, 4), B is 11-(9-acridinyl)dipyrido[3,2-a:2',3'-c]phenazine (acdppz in 1 and 3), dipyrido[3,2-a:2',3'-c]phenazine (in 2) and 1,10-phenanthroline (in 4), were synthesized, characterized and their photocytotoxicity in visible light, intracellular localization, cellular uptake and DNA photocleavage activity were studied. Complex 4 was characterized by X-ray crystallography. Complexes 1 and 3 having acdppz as photosensitizer showed significant photocytotoxicity in visible light in HeLa and MCF7 cells giving IC50 value of <0.6 μM, while being relatively non-toxic in dark. The complexes were non-toxic to non-tumorigenic HPL1D cells both in light and dark conditions. Complex 1 showed significant localization in the cytoplasm of HeLa cells within 4 h of treatment, as evidenced from confocal microscopy. DCFDA assay on 1 suggested generation of intracellular reactive oxygen species in HeLa cells upon photo-exposure. Importantly, Annexin-V-FITC/PI assay indicated photo-induced apoptotic cell death. PMID:27423638

  5. 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.

  6. 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

  7. A bis(acetylacetonato)uranium(IV) complex of the Schiff base N,N'-bis(3-hydroxysalicylidene)-2-methyl-1,2-propanediamine.

    PubMed

    Salmon, Lionel; Thuéry, Pierre; Ephritikhine, Michel

    2003-06-01

    The title complex, bis(acetylacetonato-kappa(2)O,O')[N,N'-bis(3-hydroxy-2-oxidobenzaldimino)-2-methyl-1,2-propanediamine-kappa(4)N,O,O',N']uranium(IV) tetrahydrofuran solvate, [U(C(18)H(18)N(2)O(4))(C(5)H(7)O(2))(2)].C(4)H(8)O, is a rare example of a uranium(IV) complex with a compartmental Schiff base. The U atom is located in the N(2)O(2) inner site of the hexadentate N,N'-bis(3-hydroxy-2-oxidobenzaldimino)-2-methyl-1,2-propanediamine group and is bound also to the two O atoms of both acetylacetonate moieties, which results in a dodecahedral coordination environment. Centrosymmetric dimers are formed through intermolecular hydrogen bonds that link the terminal uncoordinated hydroxy groups to one another and to the O atoms of the acetylacetonate ligands. PMID:12794336

  8. Novel mechanistic aspects on the reaction between low spin Fe(II) Schiff base amino acid complexes and hydrogen peroxide-spectrophotometric tracer of intraperoxo intermediate catalyzed reaction.

    PubMed

    Awad, Aida M; Shaker, Ali Mohamad; Zaki, Ahmad Borhan El-Din; Nassr, Lobna Abdel-Mohsen Ebaid

    2008-12-01

    The kinetics and mechanism of the reaction of hydrogen peroxide with some Fe(II) Schiff base complexes were investigated spectrophotometrically in aqueous solution at pH 8 and 35 degrees C under pseudo-first-order conditions. The used ligands were derived from salicylaldehyde or o-hydroxynaphthaldehyde and some amino acids (l-leucine, l-iso-leucine, l-serine, l-methionine and dl-tryptophan). It was found that the formation of the purple interaperoxo complex appears only above pH 7.5. The reaction consists of two steps. The first step involves reversible formation of the intraperoxo intermediate which renders irreversible at pH 8. The second step consists of inner-sphere electron transfer. The suggested scheme illustrated first-order kinetics at low [H(2)O(2)] and zero-order at high [H(2)O(2)]. Moreover, the activation parameters of the reaction were evaluated. PMID:18394952

  9. Cationic half-sandwich Ru(II) complexes containing (N,N)-bound Schiff-base ligands: Synthesis, crystal structure analysis and spectroscopic studies

    NASA Astrophysics Data System (ADS)

    Tao, Li; Miao, Qian; Tehrani, Alireza Azhdari; Hajiashrafi, Taraneh; Hu, Mao-Lin; Morsali, Ali

    2016-08-01

    Three Ru(II) half-sandwich complexes containing (N,N)-bound Schiff-base ligands, [(η6-C6H6) RuCl(L1)]PF6 (1) L1 = (E)-1-(6-methylpyridin-2-yl)-N-(p-tolyl)methanimine, [(η6-p-cymene)RuCl(L1)]PF6 (2) and [(η6-p-cymene)RuCl(L2)]PF6(3) L2 = (E)-1-(6-bromopyridin-2-yl)-N-(p-tolyl)methanimine, were synthesized, characterized and their supramolecular structures were analyzed. The crystal packing of these compounds was studied using geometrical analysis and Hirshfeld surface analysis. The fluorescence behavior of these compounds was also studied. TD-DFT calculations were carried out to better understand the fluorescence properties of complexes 1-3. These compounds could be promising for the design of organometallic dye systems.

  10. Dinuclear and 1D iron(III) Schiff base complexes bridged by 4-salicylideneamino-1,2,4-triazolate: X-ray structures and magnetic properties.

    PubMed

    Herchel, Radovan; Pavelek, Lubomír; Trávníček, Zdeněk

    2011-11-28

    Four new iron(III) complexes were obtained by the reaction of 4-salicylideneamino-1,2,4-triazole (Hsaltrz) and selected dinuclear μ-oxo-bridged iron(III) Schiff base complexes [{FeL(4)}(2)(μ-O)], where L(4) represents a terminal tetradentate dianionic Schiff-base ligand. X-ray structural analysis revealed a novel bridging mode of κN,κO of the saltrz ligand to form dinuclear complexes [{Fe(salen)(μ-saltrz)}(2)]·CH(3)OH (1) (H(2)salen = N,N'-ethylenebis(salicylimine)) and [{Fe(salpn)(μ-saltrz)}(2)] (2) (H(2)salpn = N,N'-1,2-propylenbis(salicylimine)), whereas one-dimensional (1D) zig-zag chains were formed in the case of [{Fe(salch)(μ-saltrz)}·0.5CH(3)OH](n) (3) (H(2)salch = N,N'-cyclohexanebis(salicylimine)) and [Fe(salophen)(μ-saltrz)](n) (4) (H(2)salophen = N,N'-o-phenylenebis(salicylimine)). It was also shown that the rigidity of the terminal ligand L(4) can be considered as the key factor for the molecular dimensionality of the products. The thorough magnetic analysis based on SQUID experiments, including the isotropic exchange and the zero-field splitting of both temperature and field dependent data, was performed for dimeric (1 and 2) and also for polymeric compounds (3 and 4) and revealed weak antiferromagnetic exchange mediated by the saltrz anions with much larger D-parameter (|D|≫|J|). PMID:21968851

  11. 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.

  12. Synthesis, structural characterization and DFT calculation on a square-planar Ni(II) complex of a compartmental Schiff base ligand

    NASA Astrophysics Data System (ADS)

    Biswas, Surajit; Dolai, Malay; Dutta, Arpan; Ali, Mahammad

    2016-12-01

    Reaction of a symmetric compartmental Schiff-base ligand, (H2L) with nickel(II) perchlorate hexahydrate in 1:1 M ratio in methanol gives rise to a mononuclear nickel(II) compound, NiL (1). The compound has been characterized by C, H, N microanalyses and UV-Vis spectra. The single crystal X-ray diffraction studies reveal a square planar geometry around the Ni(II) center. The compound crystallizes in monoclinic system with space group C2/c with a = 21.6425(6), b = 9.9481(3), c = 13.1958(4) Å, β = 107.728(2)°, V = 2706.16(14) Å3 and Z = 4. Ground state DFT optimization and TDDFT calculations on the ligand and complex were performed to get their UV-Vis spectral pattern.

  13. 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.

  14. 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.

  15. 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.

    PubMed

    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, (1)H NMR, and (13)C NMR. Particle sizes of synthesized compounds were measured with dynamic light scattering (DLS) analyser which indicates that particle diameter are of the range ca. 100-200nm. 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.

  16. Some metal complexes of three new potentially heptadentate (N4O3) tripodal Schiff base ligands; synthesis, characterizatin and X-ray crystal structure of a novel eight coordinate Gd(III) complex

    NASA Astrophysics Data System (ADS)

    Golbedaghi, Reza; Moradi, Somaeyh; Salehzadeh, Sadegh; Blackman, Allan G.

    2016-03-01

    The symmetrical and asymmetrical potentially heptadentate (N4O3) tripodal Schiff base ligands (H3L1-H3L3) were synthesized from the condensation reaction of three tripodal tetraamine ligands tpt (trpn), tris (3-aminopropyl) amine; ppe (abap), (2-aminoethyl)bis(3-aminopropyl)amine, and tren, tris(2-aminoethyl)amine, with 5-methoxysalicylaldehyde. Then, the reaction of Ln(III) (Ln = Gd, La and Sm), Al(III), and Fe(III) metal ions with the above ligands was investigated. The resulting compounds were characterized by IR, mass spectrometry and elemental analysis in all cases and NMR spectroscopy in the case of the Schiff base ligands. The X-ray crystal structure of the Gd complex of H3L3 ligand showed that in addition to all donor atoms of the ligand one molecule of H2O is also coordinated to the metal ion and a neutral eight-coordinate complex is formed.

  17. New macrocyclic schiff base complexes incorporating a homopiperazine unit: Synthesis of some Co(II), Ni(II),Cu(II) and Zn(II) complexes and crystal structure and theoretical studies

    NASA Astrophysics Data System (ADS)

    Keypour, Hassan; Rezaeivala, Majid; Ramezani-Aktij, Ameneh; Bayat, Mehdi; Dilek, Nefise; Ünver, Hüseyin

    2016-07-01

    A new macrocyclic Schiff base ligand, L, was synthesized by condensation reaction of 1,4-bis(2-formylphenyl)homopiperazine and 1,4-diaminobutane in acetonitrile. The Schiff base ligand was characterized by using elemental analyses, FT-IR, 1H, 13C NMR and mass spectroscopic techniques. The metal (II) complexes [ML], were synthesized from the reaction of MCl2.nH2O (M: Co, Ni, Cu and Zn) with Schiff base ligand, L and characterized by elemental analyses and FT-IR. X-ray crystal structure of [CoLCl]+ distorted square pyramidal geometry with an N4Cl core, arising from coordination by the four donor nitrogen atoms from the macrocyclic framework and one Cl atom. It crystallizes triclinic space group, P-1 with a = 7.1777(1) Å, b = 11.0357 (2) Å, c = 15.1520(2) Å, V = 1183.14(3), Z = 2, Dc = 1.556 g cm-3, μ (MoKα) = 0.156 mm-1. Also, the bonding situation between the [MCl]+ and Ligand (L) fragments in [MLCl]ClO4 (M = Co(II), Ni(II), Cu(II), Zn(II)) complexes were carried out by energy-decomposition analysis (EDA). The results showed that there is an increasing trend in the case of ΔEelstat of the complexes by changing the M from Co(II) to Zn(II).

  18. 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

    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.

  19. 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

  20. Synthesis and spectroscopic studies of some cadmium(II) and mercury(II) complexes of an asymmetrical bidentate Schiff base ligand

    NASA Astrophysics Data System (ADS)

    Montazerozohori, Morteza; Joohari, Shiva; Musavi, Sayed Alireza

    2009-07-01

    Synthesis and spectroscopic studies on four-coordinate complexes of cadmium(II) and mercury(II) halides with a new asymmetrical bidentate Schiff base ligand of N,N'-bis[α-methylcinamaldehydene]propane-1,2-diamine(L) are described. The ligand and its complexes were characterized by elemental analysis, molar conductance, UV-visible spectra, FT-IR spectra, MS, 1H NMR and 13C NMR spectra. The complexes are non-electrolytes in DMF. The electronic spectra of the complexes were recorded in DMF solution. 1H and 13 C NMR spectra been studied in CDCl3. The molar conductance as well as spectral properties indicated the complexes do not dissociate in DMF and retain their coordination. FT-IR and NMR spectra of the complexes exhibit downfield as well as upfield shifts of the free ligand resonances that show change in geometry during the coordination. The suggested structure of the complexes is pseudo-tetrahedral. Molecular structures of the complexes have been optimized by MM+ calculations that supported pseudo-tetrahedral geometry around the metal (II) ions.

  1. Synthesis, characterization and cytotoxicity of rare earth metal ion complexes of N,N‧-bis-(2-thiophenecarboxaldimine)-3,3‧-diaminobenzidene, Schiff base ligand

    NASA Astrophysics Data System (ADS)

    Shakir, Mohammad; Abbasi, Ambreen; Faraz, Mohammad; Sherwani, Asif

    2015-12-01

    Lanthanide complexes of La3+, Pr3+, Nd3+, Gd3+, Er3+ of general formula [Ln2 L(H2O)4(NO3)4](NO3)2·2H2O have been synthesized from Schiff base, N,N‧-bis-(2-thiophenecarboxaldimine)-3,3‧-diaminobenzidene. The complexes were characterized by elemental analysis, molar conductance, UV-Vis, fluorescence, FT-IR,1H NMR, mass spectroscopy, EDX, SEM and thermal analysis. FT-IR spectral data suggested that ligand coordinate with metal ions through azomethine nitrogen and uncondensed amino group. Molar conductance data revealed 1:2 electrolytic nature of complexes. From the analytical data, the stoichiometry of the complexes was found to be 1:2 (ligand:metal). Thephysico-chemical data suggested eight coordination number for Ln(III)Schiffbase complexes. SEM analysis shows morphological changes in the surfaces of complexes as compared to free ligand. Thermal decomposition profiles were consistent with proposed formulations. The anticancer activity of the complexes and theSchiffbase ligand has been studied towards human cervical cancer celllines (HeLa) and human breast cancer cell lines (MCF-7) and it was found that complexes exhibited greater activity than theSchiffbase.

  2. Ternary oxovanadium(IV) complexes of ONO-donor Schiff base and polypyridyl derivatives as protein tyrosine phosphatase inhibitors: synthesis, characterization, and biological activities.

    PubMed

    Yuan, Caixia; Lu, Liping; Gao, Xiaoli; Wu, Yanbo; Guo, Maolin; Li, Ying; Fu, Xueqi; Zhu, Miaoli

    2009-08-01

    A series of oxovanadium complexes with mixed ligands, a tridentate ONO-donor Schiff base ligand [viz., salicylidene anthranilic acid (SAA)], and a bidentate NN ligand [viz., 2,2'-bipyridine (bpy), 1,10-phenanthroline (phen), dipyrido[3,2-d:2',3'-f]quinoxaline (dpq), dipyrido[3,2-a:2',3'-c]phenazine (dppz), or 7-methyldipyrido[3,2-a:2',3'-c]phenazine (dppm)], have been synthesized and characterized by elemental analysis, electrospray ionization mass spectrometry, UV-vis spectroscopy, Fourier transform IR spectroscopy, EPR spectroscopy, and X-ray crystallography. Crystal structures of both complexes, [V(IV)O(SAA)(bpy)].0.25bpy and [V(IV)O(SAA)(phen)].0.33H(2)O, reveal that oxovanadium(IV) is coordinated with one nitrogen and two oxygen atoms from the Schiff base and two nitrogen atoms from the bidentate planar ligands, in a distorted octahedral geometry (VO(3)N(3)). The oxidation state of V(IV) with d(1) configuration was confirmed by EPR spectroscopy. The speciation of VO-SAA-bpy in aqueous solution was investigated by potentiomtreic pH titrations, and the results revealed that the main species are two ternary complexes at a pH range of 7.0-7.4, and one is the isolated crystalline complex. The complexes have been found to be potent inhibitors against human protein tyrosine phosphatase 1B (PTP1B) (IC(50) approximately 30-61 nM), T-cell protein tyrosine phosphatase (TCPTP), and Src homology phosphatase 1 (SHP-1) in vitro. Interestingly, the [V(IV)O(SAA)(bpy)] complex selectively inhibits PTP1B over the other two phosphatases (approximate ninefold selectivity against SHP-1 and about twofold selectivity against TCPTP). Kinetics assays suggest that the complexes inhibit PTP1B in a competitive and reversible manner. These suggest that the complexes may be promising candidates as novel antidiabetic agents. PMID:19290551

  3. Reactivity of nitrido complexes of ruthenium(VI), osmium(VI), and manganese(V) bearing Schiff base and simple anionic ligands.

    PubMed

    Man, Wai-Lun; Lam, William W Y; Lau, Tai-Chu

    2014-02-18

    Nitrido complexes (M≡N) may be key intermediates in chemical and biological nitrogen fixation and serve as useful reagents for nitrogenation of organic compounds. Osmium(VI) nitrido complexes bearing 2,2':6',2″-terpyridine (terpy), 2,2'-bipyridine (bpy), or hydrotris(1-pyrazolyl)borate anion (Tp) ligands are highly electrophilic: they can react with a variety of nucleophiles to generate novel osmium(IV)/(V) complexes. This Account describes our recent results studying the reactivity of nitridocomplexes of ruthenium(VI), osmium(VI), and manganese(V) that bear Schiff bases and other simple anionic ligands. We demonstrate that these nitrido complexes exhibit rich chemical reactivity. They react with various nucleophiles, activate C-H bonds, undergo N···N coupling, catalyze the oxidation of organic compounds, and show anticancer activities. Ruthenium(VI) nitrido complexes bearing Schiff base ligands, such as [Ru(VI)(N)(salchda)(CH3OH)](+) (salchda = N,N'-bis(salicylidene)o-cyclohexyldiamine dianion), are highly electrophilic. This complex reacts readily at ambient conditions with a variety of nucleophiles at rates that are much faster than similar reactions using Os(VI)≡N. This complex also carries out unique reactions, including the direct aziridination of alkenes, C-H bond activation of alkanes and C-N bond cleavage of anilines. The addition of ligands such as pyridine can enhance the reactivity of [Ru(VI)(N)(salchda)(CH3OH)](+). Therefore researchers can tune the reactivity of Ru≡N by adding a ligand L trans to nitride: L-Ru≡N. Moreover, the addition of various nucleophiles (Nu) to Ru(VI)≡N initially generate the ruthenium(IV) imido species Ru(IV)-N(Nu), a new class of hydrogen-atom transfer (HAT) reagents. Nucleophiles also readily add to coordinated Schiff base ligands in Os(VI)≡N and Ru(VI)≡N complexes. These additions are often stereospecific, suggesting that the nitrido ligand has a directing effect on the incoming nucleophile. M≡N is also

  4. Oxophily of gadolinium(III) and synthesis of dissymmetric di(Schiff bases) and dissymmetric dinuclear compounds. Crystal structure of [Cu[sub 2]L[prime](OH)](ClO[sub 4])[sub 2][center dot]H[sub 2]O with L[prime] = 2-[N-(2-pyridylethyl)formimidoyl]-6-[N-((dimethylamino)propyl)formimidoyl]phenolato

    SciTech Connect

    Andruh, M.; Kahn, O.; Sainton, J. ); Dromzee, Y.; Jeannin, S. )

    1993-04-28

    The strong oxophilic character of the Gd(III) ion has been utilized to protect one of the carbonyl functions of 2,6-diformyl-4-methylphenol, which has allowed the quantitative synthesis of mono(Schiff bases), then dissymmetric di(Schiff bases). The synthetic process is as follows: the reaction of 2,6-diformyl-4-methylphenol with a primary amine RNH[sub 2] in the presence of Gd(III) affords a complex in which Gd(III) is coordinated to two mono(Schiff bases) through their carbonyl and phenolic oxygen atoms. The mono(Schiff base) may be isolated by precipitation of Gd(III) in the form of gadolinium(III) oxalate. The reaction of another primary amine, R[prime]NH[sub 2], on this mono(Schiff base) affords a dissymmetric di(Schiff base), from which dissymmetric dinuclear compounds can be synthesized. For example, this reaction has been carried out with RNH[sub 2] = 2-(2-aminoethyl)pyridine and R[prime]NH[sub 2] = N,N-dimethylpropylenediamine. The mono(Schiff base) 2-formyl-6-(N-(2-pyridylethyl)formimidoyl)-4-methylphenol (HL) and the di(Schiff base) 2-[N-(2-pyridylethyl)formimidoyl]-6-[N-((dimethylamino)propyl)formimidoyl]-4-methylphenol (HL[prime]) have been unambiguously characterized from their [sup 1]H NMR spectra. The copper(II) dinuclear compound [CuL[prime](OH)](ClO[sub 4])[sub 2][center dot]H[sub 2]O obtained from this di(Schiff base) has been synthesized, and its crystal structure has been solved. 36 refs., 2 figs., 5 tabs.

  5. Asymmetric synthesis of α-amino acids via homologation of Ni(II) complexes of glycine Schiff bases; Part 1: alkyl halide alkylations.

    PubMed

    Sorochinsky, Alexander E; Aceña, José Luis; Moriwaki, Hiroki; Sato, Tatsunori; Soloshonok, Vadim A

    2013-10-01

    Alkylations of chiral or achiral Ni(II) complexes of glycine Schiff bases constitute a landmark in the development of practical methodology for asymmetric synthesis of α-amino acids. Straightforward, easy preparation as well as high reactivity of these Ni(II) complexes render them ready available and inexpensive glycine equivalents for preparing a wide variety of α-amino acids, in particular on a relatively large scale. In the case of Ni(II) complexes containing benzylproline moiety as a chiral auxiliary, their alkylation proceeds with high thermodynamically controlled diastereoselectivity. Similar type of Ni(II) complexes derived from alanine can also be used for alkylation providing convenient access to quaternary, α,α-disubstituted α-amino acids. Achiral type of Ni(II) complexes can be prepared from picolinic acid or via recently developed modular approach using simple secondary or primary amines. These Ni(II) complexes can be easily mono/bis-alkylated under homogeneous or phase-transfer catalysis conditions. Origin of diastereo-/enantioselectivity in the alkylations reactions, aspects of practicality, generality and limitations of this methodology is critically discussed.

  6. Synthesis, structural and biochemical activity studies of a new hexadentate Schiff base ligand and its Cu(II), Ni(II), and Co(II) complexes

    NASA Astrophysics Data System (ADS)

    Ekmekcioglu, Pinar; Karabocek, Nevin; Karabocek, Serdar; Emirik, Mustafa

    2015-11-01

    A new Schiff base ligand (H2L) and its metal complexes have been prepared and characterized by elemental analysis, magnetic moment and spectral studies. The comparative in-vitro antimicrobial activities against various pathogens with reference to known antibiotics activity under the standard control of different concentrations revealed that the metal complexes (6-8) showed enhanced antimicrobial activities in general as compared to free ligand. As an exception, the free ligand showed better activity against Trichoderma. The antifungal activity experiments were performed in triplicate. The order of biochemical activity for metal complexes were observed as in the following. CuL > CoL > NiL, which is exactly same as the order of stability constants of these complexes. Additionally, we performed DFT and TD-DFT calculation for free ligand and Cu(II) complex to support the experimental data. The geometries of the Cu(II) complex have been optimized using the B3LYP level of theory. The theoretical calculations confirm that the copper (II) center exhibits a distorted square pyramidal geometry which is favored by experimental results.

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

    NASA Astrophysics Data System (ADS)

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

    2015-06-01

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

  8. Synthesis and spectroscopic characterization of copper(II) complexes with the polydentate chelating ligand 4,4'-[1,4-phenylenedi(nitrilo)dipente-2-one

    NASA Astrophysics Data System (ADS)

    Shauib, Nadia M.; Elassar, Abdel-Zaher A.; El-Dissouky, Ali

    2006-03-01

    A new series of complexes of 4,4'-[1,4-phenylenenedi(nitilo)]dipenten-2-one, (H 2L) with CuX 2· nH 2O, X = Cl, Br, ClO 4, NO 3 and OAc; n = 1-6 as well as their ethylenediamine adducts have been synthesized and characterized by different physical techniques. The formulation of the complexes is assumed based on their elemental analysis and the molar conductivity. The products are found to be pH-dependent. The IR data showed that the ligand acts as dibasic tetradentate coordinated to copper(II) ions through the enolato-oxygen and the azomethine nitrogen atoms. Electronic, ESR spectra and room temperature magnetic moments indicate that complexes 1- 9 are square planar while complexes 10 and 11 are square based pyramidal. The different electronic spectral and ESR parameters are calculated and used to describe the nature of ligand-metal bonding ( σ and π) as well as to estimate the extent of distortion. A macrocyclic containing copper(II) complex, 12 have been isolated by the reaction of Schiff-base with copper(II)-ethylenediamine mixture. The ligand (H 2L) is designed as a building block for larger molecules and superamolecular assemblies.

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

    NASA Astrophysics Data System (ADS)

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

    2016-03-01

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

  10. Crystal structures, DFT calculations and Hirshfeld surface analyses of three new cobalt(III) Schiff base complexes derived from meso-1,2-diphenyl-1,2-ethylenediamine

    NASA Astrophysics Data System (ADS)

    Masoudi, Mohaddeseh; Behzad, Mahdi; Arab, Ali; Tarahhomi, Atekeh; Rudbari, Hadi Amiri; Bruno, Giuseppe

    2016-10-01

    Three new Cobalt(III) Schiff base complexes were synthesized and characterized by spectroscopic methods and x-ray crystallography. The DFT optimized structures of the complexes agreed well with the corresponding x-ray structures. According to the calculated vibrational normal modes, the observed signals in the IR spectra of the complexes were assigned. The experimental UV-Vis spectra of the complexes were also discussed considering the calculated excited states and molecular orbitals. Hirshfeld surface analysis was carried out to study the inter-contact interactions in these complexes. These studies provided comprehensive description of such inter-contact interactions by means of an appealing graphical approach using 3D Hirshfeld surfaces and 2D fingerprint plots derived from the surfaces. It indicated the dominant role of various hydrogen intermolecular interactions such as H⋯H (above 60%), C⋯H/H⋯C (near 15%-20%), O⋯H/H⋯O (about 16% or 17% for structures with counter ion ClO4-) and H⋯F (17% for structure with counter ion PF6-) contacts into the crystal packing which are discussed in details.

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

    NASA Astrophysics Data System (ADS)

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

    2011-05-01

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

  12. Synthesis, characterization and electrochemical behavior of some Ni(II), Cu(II), Co(II) and Cd(II) complexes of ONS type tridentate Schiff base ligand

    NASA Astrophysics Data System (ADS)

    Durmus, Sefa; Atahan, Alparslan; Zengin, Mustafa

    2011-12-01

    Tridentate Schiff base (H 2L) ligand was synthesized via condensation of o-hydroxybenzaldehyde and 2-aminothiophenol. The metal complexes were prepared from reaction of the ligand with corresponding metal salts presence of substituted pyridine in two different solvents (MeOH or MeCN). The ligand and metal complexes were then characterized by using FTIR, TGA, 1H NMR and 13C NMR spectroscopies. The FTIR spectra showed that H 2L was coordinated to the metal ions in tridentate manner with ONS donor sites of the azomethine N, deprotonated phenolic-OH and phenolic-SH. Furthermore, substituted pyridine was coordinated to the central metal atoms. The thermal behavior of the complexes was investigated by using TGA method and dissociations indicated that substituted pyridine and ligand were leaved from coordination. This coordination of the metal complexes was correlated by 1H NMR and 13C NMR. Finally, electrochemical behavior of the ligand and a Ni(II) complex were investigated.

  13. Synthesis, crystal structures, and luminescent properties of phenoxo-bridged heterometallic trinuclear propeller- and sandwich-like Schiff-base complexes.

    PubMed

    Wang, Hailong; Zhang, Daopeng; Ni, Zhong-Hai; Li, Xiyou; Tian, Laijin; Jiang, Jianzhuang

    2009-07-01

    A series of phenoxo-bridged heterometallic Schiff-base trinuclear complexes Zn-M-Zn [M = Cd(II), Pb(II), Nd(III), Eu(III), Gd(III), Tb(III), and Dy(III)] have been synthesized by a rational structural design based on two symmetrical Schiff-base ligands N,N'-bis(3-methoxysalicylidene)propylene-1,3-diamine (H(2)L(a)) and N,N'-bis(3-methoxysalicylidene)benzene-1,2-diamine (H(2)L(b)). Single X-ray diffraction analysis reveals a similar molecular structure among the eight propeller-like and seven sandwich-type phenoxo-bridged Zn-M-Zn complexes. In the compounds Cd[Zn(L(a))Cl](2) (1), {Cd[Zn(L(b))Cl](2)}.H(2)O (2), {Pb[Zn(L(b))Cl](2)}.2H(2)O (4), {Nd[Zn(L(a))Cl](2)(H(2)O)}.0.5ZnCl(4) .2H(2)O (5), and{M(III)[Zn(L(a))Cl](2)(H(2)O)}.0.5ZnCl(4).2MeOH [M = Eu(7), Gd (9), Tb (11), and Dy (13)], two [Zn(L)Cl](-) units coordinate to the central metal ion as a tetradentate ligand using its four oxygen atoms, forming a two-blade propeller-like left-handed and right-handed chiral Zn-M-Zn configuration despite the racemic nature of the whole complexes. Compounds {Pb[Zn(L(a))Cl](2)}.MeOH (3), {Nd[Zn(L(b))Cl](2)(DMF)(OAc)}.CH(3)CN (6), {Eu[Zn(L(b))Cl](2)(DMF)(OAc)}.CH(3)CN (8), {Gd[Zn(L(b))Cl](2)(DMF)(2)}.Cl.2H(2)O (10), {Tb[Zn(L(b))Cl](2)(DMF)(2)}.Cl.2H(2)O (12), {Dy[Zn(L(b))Cl](2)(DMF)(2)}.Cl.2H(2)O (14), and {Pb[Zn(L(b))Cl](2)}.2H(2)O (15) exhibit a relatively rare sandwich-type structure with a central metal ion clamped by two [Zn(L)Cl](-) units. Photophysical studies indicate that all of the complexes exhibit luminescence both in solution and in solid sate, and there exists an energy transfer from the [Zn(L)Cl](-) unit to the central rare earth ions of Nd(III) (5 and 6), Tb(III) (11), and Dy(III) (for 13). In particular, systematic and comparative investigation of the photophysical properties of these trinuclear complexes reveals that the luminescence properties could easily be tuned by changing the central metal or the Schiff-base ligand.

  14. Binding affinities of Schiff base Fe(II) complex with BSA and calf-thymus DNA: Spectroscopic investigations and molecular docking analysis.

    PubMed

    Rudra, Suparna; Dasmandal, Somnath; Patra, Chiranjit; Kundu, Arjama; Mahapatra, Ambikesh

    2016-09-01

    The binding interaction of a synthesized Schiff base Fe(II) complex with biological macromolecules viz., bovine serum albumin (BSA) and calf thymus(ct)-DNA have been investigated using different spectroscopic techniques coupled with viscosity measurements at physiological pH and 298K. Regular amendments in emission intensities of BSA upon the action of the complex indicate significant interaction between them, and the binding interaction have been characterized by Stern Volmer plots and thermodynamic binding parameters. On the basis of this quenching technique one binding site with binding constant (Kb=(7.6±0.21)×10(5)) between complex and protein have been obtained at 298K. Time-resolved fluorescence studies have also been encountered to understand the mechanism of quenching induced by the complex. Binding affinities of the complex to the fluorophores of BSA namely tryptophan (Trp) and tyrosine (Tyr) have been judged by synchronous fluorescence studies. Secondary structural changes of BSA rooted by the complex has been revealed by CD spectra. On the other hand, hypochromicity of absorption spectra of the complex with the addition of ct-DNA and the gradual reduction in emission intensities of ethidium bromide bound ct-DNA in presence of the complex indicate noticeable interaction between ct-DNA and the complex with the binding constant (4.2±0.11)×10(6)M(-1). Life-time measurements have been studied to determine the relative amplitude of binding of the complex to ct-DNA base pairs. Mode of binding interaction of the complex with ct-DNA has been deciphered by viscosity measurements. CD spectra have also been used to understand the changes in ct-DNA structure upon binding with the metal complex. Density functional theory (DFT) and molecular docking analysis have been employed in highlighting the interactive phenomenon and binding location of the complex with the macromolecules.

  15. Binding affinities of Schiff base Fe(II) complex with BSA and calf-thymus DNA: Spectroscopic investigations and molecular docking analysis

    NASA Astrophysics Data System (ADS)

    Rudra, Suparna; Dasmandal, Somnath; Patra, Chiranjit; Kundu, Arjama; Mahapatra, Ambikesh

    2016-09-01

    The binding interaction of a synthesized Schiff base Fe(II) complex with biological macromolecules viz., bovine serum albumin (BSA) and calf thymus(ct)-DNA have been investigated using different spectroscopic techniques coupled with viscosity measurements at physiological pH and 298 K. Regular amendments in emission intensities of BSA upon the action of the complex indicate significant interaction between them, and the binding interaction have been characterized by Stern Volmer plots and thermodynamic binding parameters. On the basis of this quenching technique one binding site with binding constant (Kb = (7.6 ± 0.21) × 105) between complex and protein have been obtained at 298 K. Time-resolved fluorescence studies have also been encountered to understand the mechanism of quenching induced by the complex. Binding affinities of the complex to the fluorophores of BSA namely tryptophan (Trp) and tyrosine (Tyr) have been judged by synchronous fluorescence studies. Secondary structural changes of BSA rooted by the complex has been revealed by CD spectra. On the other hand, hypochromicity of absorption spectra of the complex with the addition of ct-DNA and the gradual reduction in emission intensities of ethidium bromide bound ct-DNA in presence of the complex indicate noticeable interaction between ct-DNA and the complex with the binding constant (4.2 ± 0.11) × 106 M- 1. Life-time measurements have been studied to determine the relative amplitude of binding of the complex to ct-DNA base pairs. Mode of binding interaction of the complex with ct-DNA has been deciphered by viscosity measurements. CD spectra have also been used to understand the changes in ct-DNA structure upon binding with the metal complex. Density functional theory (DFT) and molecular docking analysis have been employed in highlighting the interactive phenomenon and binding location of the complex with the macromolecules.

  16. Antioxidation and DNA-binding properties of binuclear lanthanide(III) complexes with a Schiff base ligand derived from 8-hydroxyquinoline-7-carboxaldehyde and benzoylhydrazine.

    PubMed

    Liu, Yongchun; Zhang, Kejun; Wu, Yun; Zhao, Junying; Liu, Jianning

    2012-08-01

    8-Hydroxyquinoline-7-carboxaldehyde (8-HQ-7-CA), Schiff-base ligand 8-hydroxyquinoline-7-carboxaldehyde benzoylhydrazone, and binuclear complexes [LnL(NO(3))(H(2)O)(2)](2) were prepared from the ligand and equivalent molar amounts of Ln(NO(3))·6H(2)O (Ln=La(3+), Nd(3+), Sm(3+), Eu(3+), Gd(3+), Dy(3+), Ho(3+), Er(3+), Yb(3+), resp.). Ligand acts as dibasic tetradentates, binding to Ln(III) through the phenolate O-atom, N-atom of quinolinato unit, and C=N and -O-C=N- groups of the benzoylhydrazine side chain. Dimerization of this monomeric unit occurs through the phenolate O-atoms leading to a central four-membered (LnO)(2) ring. Ligand and all of the Ln(III) complexes can strongly bind to CT-DNA through intercalation with the binding constants at 10(5)-10(6) M(-1). Moreover, ligand and all of the Ln(III) complexes have strong abilities of scavenging effects for hydroxyl (HO·) radicals. Both the antioxidation and DNA-binding properties of Ln(III) complexes are much better than that of ligand.

  17. Synthesis, crystal structure, DFT study and photocatalytic property of a new Ni(II) complex of a symmetric N2O4-donor bis-Schiff base ligand

    NASA Astrophysics Data System (ADS)

    Wang, Hu; Meng, Xiangmin; Fan, Chuanbin; Fan, Yuhua; Bi, Caifeng

    2016-03-01

    A new complex, Ni(C22H26N2O10S2)·2CH3OH, with a sexidentate (N2O4) symmetric bis-Schiff base ligand (C22H26N2O10S2 = 1,2-bis(2-methoxy-6-formylphenoxy)ethane-2-aminoethane-sulfonic acid) has been synthesized and characterized by physico-chemical and spectroscopic methods. The X-ray crystal structure shows that the Ni(II) atom of the complex is six-coordinated by two nitrogens from Cdbnd N groups, two oxygens from ether groups and two hydroxyl oxygens from sulfonic acid groups in the mono-ligand, forming a distorted octahedral geometry. Theoretical study of the complex is carried out by density functional theory (DFT) method and the B3LYP method employing the 6-3l+G* basis set. Moreover, the complex proved to be good candidate for the photocatalytic degradation of methylene blue.

  18. 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.

  19. Synthesis, crystal structure, DFT study and photocatalytic property of a new Ni(II) complex of a symmetric N2O4-donor bis-Schiff base ligand

    NASA Astrophysics Data System (ADS)

    Wang, Hu; Meng, Xiangmin; Fan, Chuanbin; Fan, Yuhua; Bi, Caifeng

    2016-03-01

    A new complex, Ni(C22H26N2O10S2)·2CH3OH, with a sexidentate (N2O4) symmetric bis-Schiff base ligand (C22H26N2O10S2 = 1,2-bis(2-methoxy-6-formylphenoxy)ethane-2-aminoethane-sulfonic acid) has been synthesized and characterized by physico-chemical and spectroscopic methods. The X-ray crystal structure shows that the Ni(II) atom of the complex is six-coordinated by two nitrogens from Cdbnd N groups, two oxygens from ether groups and two hydroxyl oxygens from sulfonic acid groups in the mono-ligand, forming a distorted octahedral geometry. Theoretical study of the complex is carried out by density functional theory (DFT) method and the B3LYP method employing the 6-3l+G* basis set. Moreover, the complex proved to be good candidate for the photocatalytic degradation of methylene blue.

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

    NASA Astrophysics Data System (ADS)

    Nair, M. Sivasankaran; Joseyphus, R. Selwin

    2008-09-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2013-04-01

    Cu(II), Co(II), and Ni(II) complexes were synthesized from 2-[(5-o-chlorophenylazo-2-hydroxybenzylidin)amino]-phenol Schiff base (H2L). Metal ions coordinate in a tetradentate or hexadentate features with these O2N donor ligand, which are characterized by elemental analyses, magnetic moments, infrared, Raman laser, electronic, and 1H NMR spectral studies. The elemental analysis suggests the stoichiometry to be 1:1 (metal:ligand). Reactions with Cu(II), Co(II) and Ni(II), resulted [Cu(H2L)(H2O)2(Cl)]Cl, [Co(H2L)(H2O)3]Cl2ṡ3H2O and [Ni(H2L)(H2O)2]Cl2ṡ6H2O. The thermal decomposition behavior of H2L complexes has been investigated by thermogravimetric analysis (TG/DTG) at a heating rate of 10 °C min-1 under nitrogen atmosphere. The brightness side in this study is to take advantage for the preparation and characterizations of single phases of CuO, CoO and NiO nanoparticles using H2L complexes as precursors via a solid-state decomposition procedure. The crystalline structures of products using X-ray diffractometer (XRD), morphology of particles by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX) were investigated.

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

    NASA Astrophysics Data System (ADS)

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

    2013-06-01

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

  3. Synthesis, characterization, crystal structure, DNA- and HSA-binding studies of a dinuclear Schiff base Zn(II) complex derived from 2-hydroxynaphtaldehyde and 2-picolylamine

    NASA Astrophysics Data System (ADS)

    Kazemi, Zahra; Rudbari, Hadi Amiri; Mirkhani, Valiollah; Sahihi, Mehdi; Moghadam, Majid; Tangestaninejad, Sharam; Mohammadpoor-Baltork, Iraj

    2015-09-01

    A tridentate Schiff base ligand NNO donor (HL: 1-((E)-((pyridin-2-yl)methylimino)methyl)naphthalen-2-ol was synthesized from condensation of 2-hydroxynaphtaldehyde and 2-picolylamine. Zinc complex, Zn2L2(NO3)2, was prepared from reaction of Zn(NO3)2 and HL at ambient temperature. The ligand and complex were characterized by FT-IR, 1H NMR, 13C NMR and elemental analysis (CHN). Furthermore, the structure of dinuclear Zn(II) complex was determined by single crystal X-ray analysis. The complex, Zn2L2(NO3)2, is centrosymmetric dimer in which deprotonated phenolates bridge the two Zn(II) atoms and link the two halves of the dimer. In the structure, Zinc(II) ions have a highly distorted six-coordinate structure bonded to two oxygen atoms from a bidentate nitrate group, the pyridine nitrogen, an amine nitrogen and phenolate oxygens. The interaction of dinuclear Zn(II) complex with fish sperm DNA (FS-DNA) and HSA was investigated under physiological conditions using fluorescence quenching, UV-Vis spectroscopy, molecular dynamics simulation and molecular docking methods. The estimated binding constants for the DNA-complex and HSA-complex were (3.60 ± 0.18) × 104 M-1 and (1.35 ± 0.24) × 104 M-1, respectively. The distance between dinuclear Zn(II) complex and HSA was obtained based on the Förster's theory of non-radiative energy transfer. Molecular docking studies revealed the binding of dinuclear Zn(II) complex to the major groove of FS-DNA and IIA site of protein by formation of hydrogen bond, π-cation and hydrophobic interactions.

  4. Ruthenium(III) Complexes of Heterocyclic Tridentate (ONN) Schiff Base: Synthesis, Characterization and its Biological Properties as an Antiradical and Antiproliferative Agent

    PubMed Central

    Ejidike, Ikechukwu P.; Ajibade, Peter A.

    2016-01-01

    The current work reports the synthesis, spectroscopic studies, antiradical and antiproliferative properties of four ruthenium(III) complexes of heterocyclic tridentate Schiff base bearing a simple 2′,4′-dihydroxyacetophenone functionality and ethylenediamine as the bridging ligand with RCHO moiety. The reaction of the tridentate ligands with RuCl3·3H2O lead to the formation of neutral complexes of the type [Ru(L)Cl2(H2O)] (where L = tridentate NNO ligands). The compounds were characterized by elemental analysis, UV-vis, conductivity measurements, FTIR spectroscopy and confirmed the proposed octahedral geometry around the Ru ion. The Ru(III) compounds showed antiradical potentials against 2,2-Diphenyl-1-Picrylhydrazyl (DPPH) and 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radicals, with DPPH scavenging capability in the order: [(PAEBOD)RuCl2] > [(BZEBOD)RuCl2] > [(MOABOD)RuCl2] > [Vit. C] > [rutin] > [(METBOD)RuCl2], and ABTS radical in the order: [(PAEBOD)RuCl2] < [(MOABOD)RuCl2] < [(BZEBOD)RuCl2] < [(METBOD)RuCl2]. Furthermore, in vitro anti-proliferative activity was investigated against three human cancer cell lines: renal cancer cell (TK-10), melanoma cancer cell (UACC-62) and breast cancer cell (MCF-7) by SRB assay. PMID:26742030

  5. A Lewis basicity scale in dichloromethane for amines and common nonprotogenic solvents using a zinc(II) Schiff-base complex as reference Lewis acid.

    PubMed

    Oliveri, Ivan Pietro; Maccarrone, Giuseppe; Di Bella, Santo

    2011-11-01

    A consistent, reliable scale of Lewis basicity in dichloromethane for 26 bases, involving amines and nonprotogenic solvents, is presented. A Lewis acidic Zn(II) Schiff-base complex, involving formation of stable 1:1 adducts is used as reference acid. Evaluation of binding constants is achieved from spectrophotometric titrations, by the least-squares nonlinear regression of multiwavelength spectrophotometric data. This Lewis basicity scale represents a unique set of data reflecting the actual Lewis basicity with respect this "real world" Lewis acidic species. The comparison of present Lewis basicity scale with data reported in the literature indicates that while for the involved solvents their relative basicity is scarcely affected by the reference Lewis acid, in contrast for sterically encumbered amines the Lewis basicity seems to be dependent from the reference species. Thus, Lewis basicity is governed by the steric hindrance at the donor atom and involves very different relative basicities than those predicted considering typical reference Lewis acids. This is expected to have a major involvement in the organic synthesis and catalysis, given the sterically encumbered nature of commonly involved Lewis acidic organometallic complexes.

  6. Discovery and investigation of anticancer ruthenium-arene Schiff-base complexes via water-promoted combinatorial three-component assembly.

    PubMed

    Chow, Mun Juinn; Licona, Cynthia; Yuan Qiang Wong, Daniel; Pastorin, Giorgia; Gaiddon, Christian; Ang, Wee Han

    2014-07-24

    The structural diversity of metal scaffolds makes them a viable alternative to traditional organic scaffolds for drug design. Combinatorial chemistry and multicomponent reactions, coupled with high-throughput screening, are useful techniques in drug discovery, but they are rarely used in metal-based drug design. We report the optimization and validation of a new combinatorial, metal-based, three-component assembly reaction for the synthesis of a library of 442 Ru-arene Schiff-base (RAS) complexes. These RAS complexes were synthesized in a one-pot, on-a-plate format using commercially available starting materials under aqueous conditions. The library was screened for their anticancer activity, and several cytotoxic lead compounds were identified. In particular, [(η6-1,3,5-triisopropylbenzene)RuCl(4-methoxy-N-(2-quinolinylmethylene)aniline)]Cl (4) displayed low micromolar IC50 values in ovarian cancers (A2780, A2780cisR), breast cancer (MCF7), and colorectal cancer (HCT116, SW480). The absence of p53 activation or changes in IC50 value between p53+/+ and p53-/- cells suggests that 4 and possibly the other lead compounds may act independently of the p53 tumor suppressor gene frequently mutated in cancer.

  7. Ruthenium(III) Complexes of Heterocyclic Tridentate (ONN) Schiff Base: Synthesis, Characterization and its Biological Properties as an Antiradical and Antiproliferative Agent.

    PubMed

    Ejidike, Ikechukwu P; Ajibade, Peter A

    2016-01-04

    The current work reports the synthesis, spectroscopic studies, antiradical and antiproliferative properties of four ruthenium(III) complexes of heterocyclic tridentate Schiff base bearing a simple 2',4'-dihydroxyacetophenone functionality and ethylenediamine as the bridging ligand with RCHO moiety. The reaction of the tridentate ligands with RuCl₃·3H₂O lead to the formation of neutral complexes of the type [Ru(L)Cl₂(H₂O)] (where L = tridentate NNO ligands). The compounds were characterized by elemental analysis, UV-vis, conductivity measurements, FTIR spectroscopy and confirmed the proposed octahedral geometry around the Ru ion. The Ru(III) compounds showed antiradical potentials against 2,2-Diphenyl-1-Picrylhydrazyl (DPPH) and 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radicals, with DPPH scavenging capability in the order: [(PAEBOD)RuCl₂] > [(BZEBOD)RuCl₂] > [(MOABOD)RuCl₂] > [Vit. C] > [rutin] > [(METBOD)RuCl₂], and ABTS radical in the order: [(PAEBOD)RuCl₂] < [(MOABOD)RuCl₂] < [(BZEBOD)RuCl₂] < [(METBOD)RuCl₂]. Furthermore, in vitro anti-proliferative activity was investigated against three human cancer cell lines: renal cancer cell (TK-10), melanoma cancer cell (UACC-62) and breast cancer cell (MCF-7) by SRB assay.

  8. Ruthenium(III) Complexes of Heterocyclic Tridentate (ONN) Schiff Base: Synthesis, Characterization and its Biological Properties as an Antiradical and Antiproliferative Agent.

    PubMed

    Ejidike, Ikechukwu P; Ajibade, Peter A

    2016-01-01

    The current work reports the synthesis, spectroscopic studies, antiradical and antiproliferative properties of four ruthenium(III) complexes of heterocyclic tridentate Schiff base bearing a simple 2',4'-dihydroxyacetophenone functionality and ethylenediamine as the bridging ligand with RCHO moiety. The reaction of the tridentate ligands with RuCl₃·3H₂O lead to the formation of neutral complexes of the type [Ru(L)Cl₂(H₂O)] (where L = tridentate NNO ligands). The compounds were characterized by elemental analysis, UV-vis, conductivity measurements, FTIR spectroscopy and confirmed the proposed octahedral geometry around the Ru ion. The Ru(III) compounds showed antiradical potentials against 2,2-Diphenyl-1-Picrylhydrazyl (DPPH) and 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radicals, with DPPH scavenging capability in the order: [(PAEBOD)RuCl₂] > [(BZEBOD)RuCl₂] > [(MOABOD)RuCl₂] > [Vit. C] > [rutin] > [(METBOD)RuCl₂], and ABTS radical in the order: [(PAEBOD)RuCl₂] < [(MOABOD)RuCl₂] < [(BZEBOD)RuCl₂] < [(METBOD)RuCl₂]. Furthermore, in vitro anti-proliferative activity was investigated against three human cancer cell lines: renal cancer cell (TK-10), melanoma cancer cell (UACC-62) and breast cancer cell (MCF-7) by SRB assay. PMID:26742030

  9. Effects on rat testes of the thiosemicarbazone derivative Schiff base (4-(1-phenylmethylcyclobutane-3-yl)-2-(2-hydroxybenzylidenehydrazino)thiazole) and its cadmium(II) complex.

    PubMed

    Oner, Hakan; Karatepe, Mustafa; Karatas, Fikret; Oner, Jale; Yilmaz, Ibrahim; Cukurovali, Alaaddin

    2005-01-01

    The aim of this study was to investigate structural and biochemical changes in testes of rats treated with the thiosemicarbazone derivative thiazole ring Schiff base, (4-(1-phenyl-methylcyclobutane-3-yl)-2-(2-hydroxybenzylidene-hydrazino) thiazole (L), and its Cd(II) complex (CdL(2)). The animals were divided into three groups. Group I was designated as control. The rats in groups II and III were injected subcutaneously with L or CdL(2) respectively at 150-mg kg(-1) doses at 3-day intervals for 15 days. At the end of the study, blood samples were collected for biochemical analysis, and testes were removed for histological examinations. Serum levels of vitamin A, E and MDA of the L-injected group were similar to the control group. While CdL(2) treatment decreased serum vitamin A and E levels, it increased the MDA level compared to other groups. Histologically, the testes structures of L-treated animals were similar to the control. Spermatogenic cells in seminiferous tubules of CdL(2)-treated animals displayed necrosis. Nuclei of spermatogonia and primary spermatocytes were pyknotic and heterochromatic. Homogenous pink particles were present in place of the spermatids. The interstitial areas were oedematous and intertubular vessels were plugged. In conclusion, the present results indicate that L does not cause biochemical and morphological alterations, but its Cd(II) complex has degenerative effects in normal rat testes.

  10. The first salen-type ligands derived from 3',5'-diamino-3',5'-dideoxythymidine and -dideoxyxylothymidine and their corresponding copper(II) complexes

    PubMed Central

    Koth, Daniel; Gottschaldt, Michael; Görls, Helmar; Pohle, Karolin

    2006-01-01

    Background There are many nucleoside metal complexes known. According to observations made, only very few of them reveal their central ion to be co-ordinated by the sugar part of their molecules. The regio- and stereospecific exchange of the hydroxyl groups at the sugar moiety by chelating units improves its complexation ability and should give access to a new class of chiral ligands. Results In this paper we present the synthesis of 3',5'-diamino substituted thymidines with ribo- as well as xylo-configuration and the preparation of copper(II) complexes derived from their corresponding Schiff bases. Starting from thymidine, the amino derivatives were prepared in a three and four step reaction sequence respectively. The absolute configuration of the ligands was proved by the three-bond 1H-1H spin spin coupling constants 3J obtained by NMR-studies. Condensation of the amino derivatives with salicylic aldehydes resulted in the corresponding diimines, which represent a new class of chiral salen-type ligands. All ligands formed uncharged stable copper(II) complexes. The structure of 3',5'-bis(3,5-di-tert-butylsalicylaldiminato)-3',5'-dideoxyxylothymidine-copper(II) could be determined by single crystal X-ray structure analysis. The copper centre in this complex has distorted tetrahedral coordination geometry. Conclusion For the synthesis of 3',5'-diamino-3',5'-dideoxy thymidines with xylo- as well as ribo-configuration an effective synthesis pathway has been developed. Their corresponding salicylidene imines form stable coordination compounds with copper(II) ions. They represent the first salen type complexes of nucleosides with this substitution pattern. PMID:16934149

  11. A new bioactive Schiff base ligands derived from propylazo-N-pyrimidin-2-yl-benzenesulfonamides Mn(II) and Cu(II) complexes: Synthesis, thermal and spectroscopic characterization biological studies and 3D modeling structures

    NASA Astrophysics Data System (ADS)

    Tawfik, Abdelrazak M.; El-ghamry, Mosad A.; Abu-El-Wafa, Samy M.; Ahmed, Naglaa M.

    2012-11-01

    New series of Schiff base ligand H2L and their Cu(II) and Mn(II) complexes derived from azosulfapyrimidine were synthesized and characterized by elemental and thermal studies conductance measurements IR, electronic and EPR spectra. 3D modeling of the ligand indicate that azo group does not participate in complex formation and surface potential on one of the ligand under study indicate that electron density around azomethine groups are much higher than the azo group therefore coordination takes place around azomethine groups. The variety in the geometrical structures depends on the nature of both the metal ions and the Schiff base ligands. The thermo kinetic parameters are calculated and discussed. The biological activities of the ligands and complexes have been screened in vitro against some bacteria and fungi to study their capacity to inhibit their growth and to study the toxicity of the compounds.

  12. Electrocatalytic oxidation of 2-mercaptoethanol using modified glassy carbon electrode by MWCNT in combination with unsymmetrical manganese (II) Schiff base complexes

    SciTech Connect

    Mohebbi, Sajjad Eslami, Saadat

    2015-06-15

    Highlights: • High electocatalytic efficiency and stability of modified hybrid electrode GC/MWCNTs/MnSaloph. • Direct reflection of catalytic activity of manganese complexes on electrocatalytic oxidation of 2-ME. • Decreasing overpotential and increasing catalytic peak current toward oxidation of 2-ME. • Deposition of range of novel substituted N{sub 2}O{sub 2} Saloph complexes of manganese(II) on GCE/MWCNT. • Enhancement of electrocatalytic oxidation activity upon electron donating substitutions on the Saloph. - Abstract: The performance of modified hybrid glassy carbon electrode with composite of carbon nanotubes and manganese complexes for the electrocatalytic oxidation of 2-mercaptoethanol is developed. GC electrode was modified using MWCNT and new N{sub 2}O{sub 2} unsymmetrical tetradentate Schiff base complexes of manganese namely Manganese Saloph complexes 1-5, with general formula Mn[(5-x-4-y-Sal)(5-x′-4-y′-Sal) Ph], where x, x′ = H, Br, NO{sub 2} and y, y′ = H, MeO. Direct immobilization of CNT on the surface of GCE is performed by abrasive immobilization, and then modified by manganese(II) complexes via direct deposition method. These novel modified electrodes clearly demonstrate the necessity of modifying bare carbon electrodes to endow them with the desired behavior and were identified by HRTEM. Also complexes were characterized by elemental analyses, MS, UV–vis and IR spectroscopy. Modified hybrid GC/MWCNT/MnSaloph electrode exhibits strong and stable electrocatalytic activity towards the electrooxidation of 2-mercaptoethanol molecules in comparison with bare glassy carbon electrode with advantages of very low over potential and high catalytic current. Such ability promotes the thiol’s electron transfer reaction. Also, electron withdrawing substituent on the Saloph was enhanced electrocatalytic oxidation activity.

  13. 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.

  14. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2006-07-01

    Two series of new binuclear complexes with Schiff base ligands, H 4L a or H 2L b, derived from the reaction of 4,6-diacetylresorcinol and ethylenediamine, in the molar ratio 1:1 and 1:2 have been prepared, respectively. The two ligands react with Co(II), Ni(II), Cu(II), Zn(II), Cd(II), Cr(III) and Fe(III)-nitrates to get binuclear complexes. The ligands were characterized by elemental analysis, IR, UV-vis, 1H NMR and mass spectra. The complexes were synthesized by direct and template methods. Different types of products were obtained for the same ligand and metal salts according to the method of preparation. The H 4L a ligand behaves as a macrocyclic tetrabasic with two N 2O 2 sits, while the H 2L b ligand behaves as a dibasic with two N 2O sites. The H 4L a ligand is a compartmental ligand which hosts the two metal ions at the centers of two cis-N 2O 2 sites, while the metal complexes of H 2L b ligand are binuclear, where the ligand hosts two metal ions at the centers of two N 2O sites. In both cases, deprotonation of the hydrogen atoms of the phenolic OH groups occur except in the case of the Ni(II), Fe(III) and Cr(III) complexes. Electronic spectra and magnetic moments of the complexes indicate that the geometries of the metal centers are either octahedral or tetrahedral. The structures are consistent with the IR, UV-vis, ESR, 1H NMR, mass spectra, and thermal gravimetric analysis (TGA/DTA) as well as conductivity and magnetic moment measurements.

  16. Biphenyl derived Schiff-base vanadium(V) complexes with pendant OH-groups--structure, characterization and hydrogen peroxide mediated sulfide oxygenation.

    PubMed

    Plitt, Patrick; Pritzkow, Hans; Kramer, Roland

    2004-08-01

    A series of mononuclear oxovanadium(v) complexes of tridentate Schiff bases HL(1)-HL(4) and H(2)L(5)-H(2)L(8) derived from 6-phenylsalicylaldehyde and 6-(2-hydroxyphenyl)salicylaldehyde and four different amines was synthesized. The systematically selected ligands contain aliphatic or aromatic nitrogen, or alkoxy- and phenoxy-oxygen as third donor atom. The complexes were characterised by spectroscopic methods in solution and the solid state. Single-crystal X-ray analyses were performed with VO(2)L(1)(), VO(2)L(3)x1/2EtOH (), VO(2)L(4)(), VO(OiPr)L(7)xiPrOH, VO(OiPr)L(8) and H(2)L(8). For all compounds the vanadium(v) cores contain distorted tetragonal pyramidal geometry around the dioxo- and oxovanadium site at which the N(2)O- and NO(2)-donor ligands bind equatorially. Complexes and display intramolecular hydrogen bonding of the pendant hydroxyphenyl group to a coordinated oxygen trans to a nitrogen atom and therefore serve as suitable models for the native site of vanadium dependent haloperoxidases. Variable-temperature (1)H NMR spectra revealed significant hydrogen bond interaction in acetonitrile solution. In situ prepared catalysts are active for hydrogen peroxide mediated oxygenation of ethyl phenyl sulfide and showed complete conversion of the substrate to ethyl phenyl sulfoxide, together with small amounts of the corresponding sulfone, as detected by GC/MS after 10 min. The complex of H(2)L(7) turned out to be most efficient while HL(1) and HL(2) were completely inactive. Catalysis is supported by the pendant OH group in the complex of HL(3), the catalyst is twice as active as the complex of HL(4). PMID:15278124

  17. Asymmetric synthesis of α-amino acids via homologation of Ni(II) complexes of glycine Schiff bases. Part 2: aldol, Mannich addition reactions, deracemization and (S) to (R) interconversion of α-amino acids.

    PubMed

    Sorochinsky, Alexander E; Aceña, José Luis; Moriwaki, Hiroki; Sato, Tatsunori; Soloshonok, Vadim

    2013-11-01

    This review provides a comprehensive treatment of literature data dealing with asymmetric synthesis of α-amino-β-hydroxy and α,β-diamino acids via homologation of chiral Ni(II) complexes of glycine Schiff bases using aldol and Mannich-type reactions. These reactions proceed with synthetically useful chemical yields and thermodynamically controlled stereoselectivity and allow direct introduction of two stereogenic centers in a single operation with predictable stereochemical outcome. Furthermore, new application of Ni(II) complexes of α-amino acids Schiff bases for deracemization of racemic α-amino acids and (S) to (R) interconversion providing additional synthetic opportunities for preparation of enantiomerically pure α-amino acids, is also reviewed. Origin of observed diastereo-/enantioselectivity in the aldol, Mannich-type and deracemization reactions, generality and limitations of these methodologies are critically discussed.

  18. Synthesis, characterization and biological relevance of some metal (II) complexes with oxygen, nitrogen and oxygen (ONO) donor Schiff base ligand derived from thiazole and 2-hydroxy-1-naphthaldehyde

    NASA Astrophysics Data System (ADS)

    Nagesh, G. Y.; Mruthyunjayaswamy, B. H. M.

    2015-04-01

    The novel Schiff base ligand 2-((2-hydroxynaphthalen-1-yl)methylene)-N-(4-phenylthiazol-2-yl)hydrazinecarboxamide (L) obtained by the condensation of N-(4-phenylthiazol-2-yl)hydrazinecarboxamide with 2-hydroxy-1-naphthaldehyde and its newly synthesized Cu(II), Co(II), Ni(II), Zn(II) and Cd(II) complexes have been characterized by microanalysis, molar conductance, IR, 1H NMR, ESI-mass, UV-Visible, TGA/DTA, ESR and powder X-ray diffraction data to explicate their structures. The IR results confirmed the tridentate binding of the ligand involving oxygen atom of amide carbonyl, azomethine nitrogen and naphthol oxygen. 1H NMR spectral data of the ligand (L) and its Zn(II) complex agreed well with the proposed structures. Thermogravimetric studies for Cu(II) and Ni(II) complexes indicated the presence of coordinated water molecules and the final product is the metal oxide. In order to appraise the effect of antimicrobial activity of metal ions upon chelation, the newly synthesized ligand and its metal complexes were screened for their antimicrobial activity by minimum inhibitory concentration (MIC) method. The DNA cleavage activities were studied using plasmid DNA pBR322 (Bangal re Genei, Bengaluru, Cat. No 105850) as a target molecule by agarose gel electrophoresis method. The brine shrimp bioassay was also carried out to study the in vitro cytotoxicity properties against Artemia salina. Furthermore, the antioxidant activity were determined in vitro by reduction of 1,1-diphenyl-2-picryl hydrazyl (DPPH). The ligand exhibited better in vitro-antioxidant activity than its metal complexes.

  19. Synthesis and characterization of novel Cu (II) complexes with 3-substituted-4-amino-5-mercapto-1,2,4-triazole Schiff bases: A new route to CuO nanoparticles

    NASA Astrophysics Data System (ADS)

    Aly, Hisham M.; Moustafa, Moustafa E.; Nassar, Moustafa Y.; Abdelrahman, Ehab A.

    2015-04-01

    Cu (II) complexes, were synthesized with newly derived biologically active 1,2,4-triazole Schiff bases. The Schiff bases were synthesized by condensation of 3-substituted-4-amino-5-mercapto-1,2,4-triazole with dibenzoylmethane. The synthesized compounds were characterized using elemental analysis, magnetic moment, thermal analysis and spectral tools (FT-IR, 1HNMR, ESR, and UV-Vis spectroscopy). All the synthesized complexes are nonelectrolytes in N,N-dimethylformamide. The synthesized Schiff bases and their Cu (II) complexes have been screened for antibacterial (Escherichia coli &Staphylococcus aureus) and antifungal (Aspergillus flavus &Candida albicans) activity using a modified Bauer-Kirby method. Interestingly, the synthesized Cu (II) complexes were used as precursors for CuO nanoparticles which were characterized using XRD, HR-TEM, FT-IR and UV-Vis spectroscopy. The photocatalytic activity of the prepared CuO nanoparticles was studied by performing the degradation of methylene blue dye under UV illumination in the presence of H2O2 and the results showed that the maximum percent of the degradation of methylene blue dye (MB) was found 96.18% after 360 min.

  20. Heterobinuclear complexes of heavy metals with 1,3,5-triketonates and their diamine Schiff-base derivates. Synthetic strategies based on positional and geometric isomerism of mononuclear palladium (II) and UO/sub 2//sup 2 +/ complexes

    SciTech Connect

    Lintvedt, R.L.; Ahmad, N.

    1982-06-01

    Several new mononuclear complexes of Pd(II) and UO/sub 2//sup 2 +/ have been prepared with the binucleating ligands 1,3,5-triketones and their Schiff-base diamine derivaties. The mononuclear complexes have been used as precursors in the preparation of heterobinuclear complexes by means of two different strategies. One depends upon the site selectivity, i.e., positional isomerism, observed for certain metal ions in the Schiff-base ligands that contain two distinctly different coordination sites. The other, which can be applied to symmetric 1,3,5-triketones, depends upon geometric isomerism. In this case, the UO/sub 2//sup 2 +/ ion binds two triketonates in a cis-type configuration due to the steric constaints of a fifth equatorial ligand. The cis complex may then be used to bind a second metal ion. Under similar conditions Pd(II) forms a trans-type complex in which it is not possible to add a second metal ion. This work describes the use of preferred isomerism to design specific heterobinuclear complexes containing heavy metal ions.

  1. Asymmetric Synthesis of Chiral α-Methyl-α,β-diamino Acid Derivatives via Group-Assisted Purification Chemistry Using N-Phosphonyl Imines and a Ni(II)-Complexed Alanine Schiff Base.

    PubMed

    Zhang, Haowei; Yang, Bing; Yang, Zhen; Lu, Hongjian; Li, Guigen

    2016-09-01

    The Mannich reaction between chiral N-phosphonyl imines and a Ni(II)-complexed alanine Schiff base (Ala-Ni) is reported. With a chiral phosphonyl auxiliary, a single isomer of α-methyl-α,β-diamino acid derivative containing vicinal chiral centers, including a chiral quaternary carbon center, can be obtained simply by washing the crude mixture with cosolvents. The absolute stereochemistry of the enantiomerically pure product has been unambiguously determined by X-ray crystallographic analysis. PMID:27459278

  2. Syntheses, crystallographic, mass-spectroscopic determination and antioxidant studies of Co(II), Ni(II) and Cu(II) complexes of a new imidazol based Schiff base.

    PubMed

    Demir, Serkan; Güder, Aytaç; Yazıcılar, Turan K; Çağlar, Sema; Büyükgüngör, Orhan

    2015-01-01

    A new imidazole-based Schiff base, 2-((1H-imidazol-4-yl)methyleneamino)benzylalcohol (HL) and corresponding analogous bis(2-((1H-imidazol-4-yl)methyleneimino)benzylalcohol)metal(II) perchlorates (M: Co(1), Ni(2), Cu(3)) have prepared and characterized by elemental analyses, ESI-MS, IR, UV-Vis spectroscopies and conductivity measurements. X-ray single crystal structures of 1 and 2 have been also determined. Elemental analyses, spectroscopic and conductance data of 3 demonstrated similar structural features with these of crystallographically characterized complexes and based upon this relevances, HL ligands are neutrally coordinated to metal(II) ions in tridentate mode and all complexes are isostructural, dicathionic, contain perchlorate anions as complementary ions and, are in octahedral geometry with the formulae of [M(HL)2](ClO4)2 (for 3) and [M(HL)2](ClO4)2·H2O (for 1 and 2). Radical scavenging activities of the complexes have been evaluated by using DPPH, DMPD(+), and ABTS(+) assays. SC50 values (μg/mL) of the complexes and standards on DPPH, DMPD(+), ABTS(+) follow the sequences, BHA (9.06±0.33)>CMPD3 (15.62±0.52)>CMPD2 (17.43±0.29)>Rutin (21.65±0.60)>CMPD1 (25.67±0.51)>Trolox (28.57±0.37), Rutin>BHA>CMPD3>CMPD2>Trolox>CMPD1, and Trolox>BHA>CMPD3>CMPD2>Rutin>CMPD1 respectively.

  3. Five coordinate M(II)-diphenolate [M = Zn(II), Ni(II), and Cu(II)] Schiff base complexes exhibiting metal- and ligand-based redox chemistry.

    PubMed

    Franks, Mark; Gadzhieva, Anastasia; Ghandhi, Laura; Murrell, David; Blake, Alexander J; Davies, E Stephen; Lewis, William; Moro, Fabrizio; McMaster, Jonathan; Schröder, Martin

    2013-01-18

    Five-coordinate Zn(II), Ni(II), and Cu(II) complexes containing pentadentate N(3)O(2) Schiff base ligands [1A](2-) and [1B](2-) have been synthesized and characterized. X-ray crystallographic studies reveal five coordinate structures in which each metal ion is bound by two imine N-donors, two phenolate O-donors, and a single amine N-donor. Electron paramagnetic resonance (EPR) spectroscopic studies suggest that the N(3)O(2) coordination spheres of [Cu(1A)] and [Cu(1B)] are retained in CH(2)Cl(2) solution and solid-state superconducting quantum interference device (SQUID) magnetometric studies confirm that [Ni(1A)] and [Ni(1B)] adopt high spin (S = 1) configurations. Each complex exhibits two reversible oxidation processes between +0.05 and +0.64 V vs [Fc](+)/[Fc]. The products of one- and two-electron oxidations have been studied by UV/vis spectroelectrochemistry and by EPR spectroscopy which confirm that each oxidation process for the Zn(II) and Cu(II) complexes is ligand-based with sequential formation of mono- and bis-phenoxyl radical species. In contrast, the one-electron oxidation of the Ni(II) complexes generates Ni(III) products. This assignment is supported by spectroelectrochemical and EPR spectroscopic studies, density functional theory (DFT) calculations, and the single crystal X-ray structure of [Ni(1A)][BF(4)] which contains Ni in a five-coordinate distorted trigonal bipyramidal geometry.

  4. 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.

  5. Syntheses, crystal structures and spectroscopic characterization of two new octahedral nickel(II) complexes of a Schiff base ligand derived from pyridoxal and 2-(pyrid-2-yl)ethylamine

    NASA Astrophysics Data System (ADS)

    Mandal, Senjuti; Modak, Ritwik; Sikdar, Yeasin; Naskar, Barnali; Goswami, Sanchita

    2014-09-01

    Two new coordination compounds based on ONN donor Schiff base ligand derived from pyridoxal and 2-(pyrid-2-yl)ethylamine, namely {[Ni(HL)(H2O)2](ClO4)2}∞ (1) and [Ni(HL)(H2O)(SCN)2] (2) have been synthesized and structurally characterized by single-crystal X-ray diffraction along with other physical techniques, including elemental analysis, IR spectra and UV-Vis studies. X-ray studies suggest that both 1 and 2 are mononuclear nickel(II) complexes and exhibit distorted octahedral geometry. In these compounds the pyridoxal based Schiff base ligand displays different coordination modes constructing various architectures.

  6. 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

  7. Microwave-assisted synthesis, characterization and biological activities of organotin (IV) complexes with some thio Schiff bases

    NASA Astrophysics Data System (ADS)

    Singh, Ran Vir; Chaudhary, Pratibha; Chauhan, Shikha; Swami, Monika

    2009-03-01

    Microwave-assisted synthesis and characterization of the organotin (IV) complexes are reported. Trigonal bipyramidal and octahedral complexes of tin (IV) have been synthesized by the reaction of dimethyltin (IV) dichloride with 4-nitrobenzanilide- S-benzyldithiocarbazate (L 1H), 4-chlorobenzanilide- S-benzyldithiocarbazate (L 2H), 4-nitrobenzanilidebenzothiazoline (L 3H) and 4-chlorobenzanilidebenzothiazoline (L 4H). The complexes so formed were characterized by elemental analysis, conductance measurements, molecular weight determinations and spectral data viz. IR, UV-Visible, 1H and 13C NMR. The anti-microbial activities of the ligands and their corresponding organotin (IV) complexes have been screened against various strains of bacteria and fungi. Antifertility activity against male albino rats has also been reported.

  8. A Schiff base connectivity switch in sensory rhodopsin signaling.

    PubMed

    Sineshchekov, Oleg A; Sasaki, Jun; Phillips, Brian J; Spudich, John L

    2008-10-21

    Sensory rhodopsin I (SRI) in Halobacterium salinarum acts as a receptor for single-quantum attractant and two-quantum repellent phototaxis, transmitting light stimuli via its bound transducer HtrI. Signal-inverting mutations in the SRI-HtrI complex reverse the single-quantum response from attractant to repellent. Fast intramolecular charge movements reported here reveal that the unphotolyzed SRI-HtrI complex exists in two conformational states, which differ by their connection of the retinylidene Schiff base in the SRI photoactive site to inner or outer half-channels. In single-quantum photochemical reactions, the conformer with the Schiff base connected to the cytoplasmic (CP) half-channel generates an attractant signal, whereas the conformer with the Schiff base connected to the extracellular (EC) half-channel generates a repellent signal. In the wild-type complex the conformer equilibrium is poised strongly in favor of that with CP-accessible Schiff base. Signal-inverting mutations shift the equilibrium in favor of the EC-accessible Schiff base form, and suppressor mutations shift the equilibrium back toward the CP-accessible Schiff base form, restoring the wild-type phenotype. Our data show that the sign of the behavioral response directly correlates with the state of the connectivity switch, not with the direction of proton movements or changes in acceptor pK(a). These findings identify a shared fundamental process in the mechanisms of transport and signaling by the rhodopsin family. Furthermore, the effects of mutations in the HtrI subunit of the complex on SRI Schiff base connectivity indicate that the two proteins are tightly coupled to form a single unit that undergoes a concerted conformational transition.

  9. Synthesis, characterization and spectroscopy studying of some metal complexes of a new Schiff base ligand; X-ray crystal structure, NMR and IR investigation of a new dodecahedron Cd(II) complex

    NASA Astrophysics Data System (ADS)

    Golbedaghi, Reza; Rezaeivala, Majid; Khalili, Maryam; Notash, Behrouz; Karimi, Javad

    2016-12-01

    Some new [Cd(H2L1)(NO3)]ClO4 (1), [Mn(H2L1)](ClO4)2 (2), [Ni(H2L1)](ClO4)2 (3) and [Cu(H2L1)](ClO4)2 (4) complexes were prepared by the reaction of a Schiff base ligand and M (II) metal ions in equimolar ratios (M = Cd, Mn, Ni and Cu). The ligand H2L1 was synthesized by reaction of 2-[2-(3-formyl phenoxy)propoxy]benzaldehyde and ethanol amine and characterized by IR, 1H,13C NMR spectroscopy and elemental analysis. The synthesized complexes were characterized with IR and elemental analysis in all cases and 1H, 13C NMR, and X-ray in the case of Cd(II) complex. The X-ray crystal structure of compound 1 showed that all nitrogen and oxygen atoms of Schiff base 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.

  10. 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.

  11. Synthesis, spectroscopic characterization and biological activity of the metal complexes of the Schiff base derived from phenylaminoacetohydrazide and dibenzoylmethane

    NASA Astrophysics Data System (ADS)

    El-Tabl, Abdou Saad; El-Saied, Fathey A.; Plass, Winfried; Al-Hakimi, Ahmed Noman

    2008-11-01

    A new series of mono and binuclear Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II), La(III), Ru(III), Hf(IV), ZrO(II) and UO 2(II) complexes of phenylaminodibenzoylhydrazone have been synthesized and characterized by elementals analyses, IR UV-vis spectra, magnetic moments, conductances, thermal analyses (DTA and TGA) and electron spin resonance (ESR) measurements. The IR spectral data show that, the ligand behaves as a neutral bidentate type ( 15 and 16), monobasic bidentate type ( 6), or monobasic tridentate type ( 5, 7, 8, 10, 11, 13, 14, 17- 21) or dibasic tridentate type 2- 4, 9 and 12 towards the metal ion. Molar conductances in DMF solution indicate that, the complexes are non-electrolytes. The ESR spectra of solid complexes ( 9 and 10) show axial and non-axial types indicating a d ground state with significant covalent bond character. However, complexes ( 11 and 12), show isotropic type, indicating manganese(II) octahedral geometry. Antibacterial and antifungal tests of the ligand and its metal complexes are also carried out and it has been observed that the complexes are more potent bactericides and fungicides than the ligand.

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

    NASA Astrophysics Data System (ADS)

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

    2015-07-01

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

  13. 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

  14. 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 (ΔΨm). 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 ΔΨm, causing the depolarization of the mitochondrial membrane. Complex 2 showed greater antitumor efficiency than that of complex 1. PMID:23424390

  15. Enantiopure tetranuclear iron(III) complexes using chiral reduced Schiff base ligands: synthesis, structure, spectroscopy, magnetic properties, and DFT studies.

    PubMed

    Singh, Reena; Banerjee, Atanu; Colacio, Enrique; Rajak, Kajal Krishna

    2009-06-01

    Four new tetranuclear iron(III) complexes of formula [{Fe(L)(2)}(3)Fe], 1-4, have been prepared by reacting [Fe(ClO(4))(3)].6H(2)O with H(2)L in methanol. Here, L(2-) is the deprotonated form of N-(2-hyrdoxybenzyl)-l-valinol (H(2)L(1)), N-(2-hyrdoxybenzyl)-l-leucinol (H(2)L(2)), N-(5-chloro-2-hyrdoxybenzyl)-l-leucinol (H(2)L(3)), and N-(2-hyrdoxybenzyl)-l-phenylalaninol (H(2)L(4)). The complexes are prepared in an enantiomeric pure form. The complexes have been characterized with the help of IR, UV-vis, circular dichroism (CD), (1)H, and elemental analyses. The complex [{Fe(L(2))(2)}(3)Fe].CH(3)OH.2H(2)O, 2.CH(3)OH.2H(2)O, crystallizes in enantiomeric pure form containing a propeller-like Fe(4)O(6) core. (1)H and CD spectral studies of the four species are consistent with the structural similarities of the complexes in solution. Variable-temperature magnetic susceptibility of one case shows an intramolecular antiferromagnetic coupling between the Fe(III) ions. Magnetic measurements are in accord with the S = 5 ground state and suggest single molecular magnet behavior. The magnetic exchange coupling constant between the iron centers within the molecule is interpreted using broken-symmetry density functional theory calculation. PMID:19466801

  16. Reversible sequential transfer of two electrons at the same potential in bis(1,3,5-triketonato)dicopper(II) complexes and their diamine Schiff bases. Effect of Na/sup +/ and similar ions on the cyclic voltammetry

    SciTech Connect

    Lintvedt, R.L.; Kramer, L.S.

    1983-03-02

    The cyclic voltammetry of four binuclear Cu(II) 1,3,5-triketonates and their diamine Schiff-base derivatives has been investigated in DMF with (C/sub 2/H/sub 5/)/sub 4/NClO/sub 4/ as the supporting electrolyte. Addition of simple cations such as Na/sup +/ to these solutions has a profound effect on the reduction potentials of the Cu(II) ions and on the stability of the reduced product. In the presence of a sufficient concentration of Na/sup +/ ions, the complexes exhibit one CV wave due to the coppers with peak separations of 42-44 mV and cathodic half-peak widths of 42-44 mV also. These results may be obtaned with no instrumental iR compensation, providing a high concentration of the supporting electrolyte is present. The process is reversible with use of the criteria of scan rate dependence of the cathodic peak current and width and the equivalence of the cathodic and anodic peak heights. Controlled-potential electrolysis results prove that the process involves the transfer of two electrons. All of the experimental facts may be explained by the reversible, sequential transfer of two electrons at the same potential. Although the two Cu(II) ions in the diamine Schiff bases are in much different coordination environments within the same molecule, they give rise to the same CV wave shapes as the triketonates; i,e., ..delta..E/sub p/ and E/sub pc/ - E/sub p///sub 2/ both are very nearly 42 mV. Thus, they also undergo two-electron transfer at the same potential. The only significant difference between the simpler binuclear Cu(II) triketonates and the diamine Schiff-base derivatives is that E/sub 1///sub 2/ values for the Schiff bases are about 0.1V more negative than for their triketonate analogues.

  17. Synthesis, X-ray, and Spectroscopic Study of Dissymmetric Tetrahedral Zinc(II) Complexes from Chiral Schiff Base Naphthaldiminate Ligands with Apparent Exception to the ECD Exciton Chirality.

    PubMed

    Enamullah, Mohammed; Makhloufi, Gamall; Ahmed, Rifat; Joy, Baitul Alif; Islam, Mohammad Ariful; Padula, Daniele; Hunter, Howard; Pescitelli, Gennaro; Janiak, Christoph

    2016-07-01

    Bidentate enantiopure Schiff base ligands, (R or S)-N-1-(Ar)ethyl-2-oxo-1-naphthaldiminate (R- or S-N^O), diastereoselectively provide Λ- or Δ-chiral-at-metal four-coordinated Zn(R- or S-N^O)2 {Ar = C6H5; Zn-1R or Zn-1S and p-C6H4OMe; Zn-2R or Zn-2S}. Two R- or S-N^O-chelate ligands coordinate to the zinc(II) in a tetrahedral mode and induce Λ- or Δ-configuration at the zinc metal center. In the solid state, the R- or S-ligand diastereoselectively gives Λ- or Δ-Zn configuration, respectively, and forms enantiopure crystals. Single crystal structure determinations show two symmetry-independent molecules (A and B) in each asymmetric unit to give Z' = 2 structures. Electronic circular dichroism (ECD) spectra show the expected mirror image relationship resulting from diastereomeric excess toward the Λ-Zn for R-ligands and Δ-Zn for S-ligands in solution. ECD spectra are well reproduced by TDDFT calculations, while the application of the exciton chirality method, in the common point-dipole approximation, predicts the wrong sign for the long-wavelength couplet. A dynamic diastereomeric equilibrium (Λ vs Δ) prevails for both R- and S-ligand-metal complexes in solution, respectively, evidenced by (1)H NMR spectroscopy. Variable temperature (1)H NMR spectra show a temperature-dependent shift of the diastereomeric equilibrium and confirm Δ-Zn configuration (for S-ligand) to be the most stable one and favored at low temperature. DSC analyses provide quantitative diastereomeric excess in the solid state for Zn-2R and Zn-2S, which is comparable to the results of solution studies.

  18. Synthesis, X-ray, and Spectroscopic Study of Dissymmetric Tetrahedral Zinc(II) Complexes from Chiral Schiff Base Naphthaldiminate Ligands with Apparent Exception to the ECD Exciton Chirality.

    PubMed

    Enamullah, Mohammed; Makhloufi, Gamall; Ahmed, Rifat; Joy, Baitul Alif; Islam, Mohammad Ariful; Padula, Daniele; Hunter, Howard; Pescitelli, Gennaro; Janiak, Christoph

    2016-07-01

    Bidentate enantiopure Schiff base ligands, (R or S)-N-1-(Ar)ethyl-2-oxo-1-naphthaldiminate (R- or S-N^O), diastereoselectively provide Λ- or Δ-chiral-at-metal four-coordinated Zn(R- or S-N^O)2 {Ar = C6H5; Zn-1R or Zn-1S and p-C6H4OMe; Zn-2R or Zn-2S}. Two R- or S-N^O-chelate ligands coordinate to the zinc(II) in a tetrahedral mode and induce Λ- or Δ-configuration at the zinc metal center. In the solid state, the R- or S-ligand diastereoselectively gives Λ- or Δ-Zn configuration, respectively, and forms enantiopure crystals. Single crystal structure determinations show two symmetry-independent molecules (A and B) in each asymmetric unit to give Z' = 2 structures. Electronic circular dichroism (ECD) spectra show the expected mirror image relationship resulting from diastereomeric excess toward the Λ-Zn for R-ligands and Δ-Zn for S-ligands in solution. ECD spectra are well reproduced by TDDFT calculations, while the application of the exciton chirality method, in the common point-dipole approximation, predicts the wrong sign for the long-wavelength couplet. A dynamic diastereomeric equilibrium (Λ vs Δ) prevails for both R- and S-ligand-metal complexes in solution, respectively, evidenced by (1)H NMR spectroscopy. Variable temperature (1)H NMR spectra show a temperature-dependent shift of the diastereomeric equilibrium and confirm Δ-Zn configuration (for S-ligand) to be the most stable one and favored at low temperature. DSC analyses provide quantitative diastereomeric excess in the solid state for Zn-2R and Zn-2S, which is comparable to the results of solution studies. PMID:27295327

  19. Synthesis, characterization and the crystal structure of a cis-dioxovandium(V) complex of a tridentate Schiff base ligand

    SciTech Connect

    Hai-Xin Liu; Wei Wang; Xin Wang; Min-Yu Tan

    1994-12-01

    The title complex, [VO{sub 2}(C{sub 6}H{sub 5}C(O)CHC(CH{sub 3})NNC(O)CH{sub 2}(NC{sub 5}H{sub 5}))]{center_dot}C{sub 2}H{sub 5}OH, was synthesized and characterized by elemental analysis and spectroscopy. Yellow crystals of the complex are monoclinic, space group P2{sub 1}/a with a = 10.690(2), b = 16.008(3), c = 13.164(4){Angstrom}, {beta} = 107.03(2){degrees}, V = 2153.9(18){Angstrom}{sup 3}, F(000) = 880 and Dc = 1.305 g cm{sup -3} for Z =4. X-ray structure analysis shows that the vanadium coordination number is five and the coordination polyhedron is a distorted trigonal bipyramid.

  20. Synthesis, characterization and separation of chiral and achiral diastereomers of Schiff base Pd(II) complex: A comparative study of their DNA- and HSA-binding.

    PubMed

    Kazemi, Zahra; Amiri Rudbari, Hadi; Sahihi, Mehdi; Mirkhani, Valiollah; Moghadam, Majid; Tangestaninejad, Sharam; Mohammadpoor-Baltork, Iraj; Azimi, Gholamhassan; Gharaghani, Sajjad; Kajani, Abolghasem Abbasi

    2016-10-01

    A racemic mixture of a new chiral Schiff base ligand (HL: R/S-(1-phenylethylimino)methylnaphtalen-2-ol) has been utilized to prepare Pd(II) complex. Crystallization technique has been employed to separate diastereomeric pairs of Pd(II) complex: (mesoPdL2) and (racPdL2) that in this paper are known as PdL2(1) and PdL2(2), respectively. The synthesized complexes have been characterized by means of elemental analysis (CHN), FT-IR, (1)H and (13)C NMR spectroscopies. Moreover, PdL2(1) has been structurally characterized by single-crystal X-ray diffraction. The geometry around the metal center is square-planar. The interaction of two diastereomers of Pd(II) complex with FS-DNA has been explored, using UV-vis spectroscopy, fluorescence quenching, chemometrics and viscosity measurement methods. The PdL2(1) exhibited higher binding constant, about 10-fold, (1.0×10(6)M(-1)) as compared to PdL2(2) (1.51.5×10(5)M(-1)). Moreover, the human serum albumin (HSA) binding ability has been monitored by absorption, quenching of tryptophan fluorescence emission and circular dichroism (CD) studies. The slight difference is observed between HSA binding affinity with the complexes: PdL2(1) (6.2×10(4)M(-1)) and PdL2(2) (3.3×10(4)M(-1)). Also, the thermodynamic parameters were determined at three different temperatures (298, 308 and 318K). In this study, molecular docking was also carried out to confirm and illustrate the specific DNA- and HSA-binding of the Pd(II) complexes. In the PdL2(1)-HSA system a T-shaped π-π interaction with PHE206 was observed. While in the PdL2(2)-HSA system there are a hydrogen bond, a π-cation and two T-shaped π-π interactions with ASB324, LYS212 and PHE228, respectively. The groove binding mode of DNA interaction has been proposed for both diastereomers.

  1. Synthesis, characterization and separation of chiral and achiral diastereomers of Schiff base Pd(II) complex: A comparative study of their DNA- and HSA-binding.

    PubMed

    Kazemi, Zahra; Amiri Rudbari, Hadi; Sahihi, Mehdi; Mirkhani, Valiollah; Moghadam, Majid; Tangestaninejad, Sharam; Mohammadpoor-Baltork, Iraj; Azimi, Gholamhassan; Gharaghani, Sajjad; Kajani, Abolghasem Abbasi

    2016-10-01

    A racemic mixture of a new chiral Schiff base ligand (HL: R/S-(1-phenylethylimino)methylnaphtalen-2-ol) has been utilized to prepare Pd(II) complex. Crystallization technique has been employed to separate diastereomeric pairs of Pd(II) complex: (mesoPdL2) and (racPdL2) that in this paper are known as PdL2(1) and PdL2(2), respectively. The synthesized complexes have been characterized by means of elemental analysis (CHN), FT-IR, (1)H and (13)C NMR spectroscopies. Moreover, PdL2(1) has been structurally characterized by single-crystal X-ray diffraction. The geometry around the metal center is square-planar. The interaction of two diastereomers of Pd(II) complex with FS-DNA has been explored, using UV-vis spectroscopy, fluorescence quenching, chemometrics and viscosity measurement methods. The PdL2(1) exhibited higher binding constant, about 10-fold, (1.0×10(6)M(-1)) as compared to PdL2(2) (1.51.5×10(5)M(-1)). Moreover, the human serum albumin (HSA) binding ability has been monitored by absorption, quenching of tryptophan fluorescence emission and circular dichroism (CD) studies. The slight difference is observed between HSA binding affinity with the complexes: PdL2(1) (6.2×10(4)M(-1)) and PdL2(2) (3.3×10(4)M(-1)). Also, the thermodynamic parameters were determined at three different temperatures (298, 308 and 318K). In this study, molecular docking was also carried out to confirm and illustrate the specific DNA- and HSA-binding of the Pd(II) complexes. In the PdL2(1)-HSA system a T-shaped π-π interaction with PHE206 was observed. While in the PdL2(2)-HSA system there are a hydrogen bond, a π-cation and two T-shaped π-π interactions with ASB324, LYS212 and PHE228, respectively. The groove binding mode of DNA interaction has been proposed for both diastereomers. PMID:27599112

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

    SciTech Connect

    Mahjoub, Omima Abdalla; Farina, Yang

    2014-09-03

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

  3. Multifunctional composites of chiral valine derivative Schiff base Cu(II) complexes and TiO2.

    PubMed

    Takeshita, Yuki; Takakura, Kazuya; Akitsu, Takashiro

    2015-02-12

    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.

  4. 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

  5. Mono- and dinuclear nickel(II) complexes of resolved Schiff-base ligands with extended quinoline substituents.

    PubMed

    Prema, Dipesh; Oshin, Kayode; Desper, John; Levy, Christopher J

    2012-04-28

    The coordination chemistry of four enantiopure tetradentate bis(iminoquinoline) ligands with nickel(II) salts is reported. The previously reported ligands CBQ, CPQ, BBQ, and BPQ result from the condensation of (1R,2R)-cyclohexyldiamine or (R)-BINAM with two equivalents of 2-formylbenzo[h]quinoline or 8-isopropyl-2-quinolinecarboxaldehyde {CBQ = (1R,2R)-cyclohexanediamine-N,N'-bis(benzo[h]quinoline-2-ylmethylene), CPQ = (1R,2R)-cyclohexanediamine-N,N'-bis[[(8-isopropyl)-2-quinolinyl]methylene], BBQ = [(R)-1,1'-binaphthalene]-2,2'-diamine-N,N'-bis(benzo[h]quinoline-2-ylmethylene), BPQ = [(R)-1,1'-binaphthalene]-2,2'-diamine-N,N'-bis[[(8-isopropyl)-2-quinolinyl]methylene]}. Reaction of NiI(2) with the (1R,2R)-cyclohexyl ligands gives the mononuclear distorted trigonal-bipyramidal (TBP) complexes [Ni(N(3)-CBQ)I(2)] and [Ni(N(3)-CPQ)I(2)]. Incomplete iodide abstraction from [Ni(N(3)-CPQ)I(2)] with AgOTf leads to partial replacement of the iodide with hydroxide from adventitious water to give [Ni(N(3)-CPQ)I(1.6)(OH)(0.4)] (distorted TBP). The corresponding reaction with [Ni(N(3)-CBQ)I(2)] again fails to remove all of the iodide, resulting instead in conversion to the syn dinuclear [Ni(2)(CBQ)(μ-X)(2)I(2)] (X = Cl(0.925)I(0.075)) complex, where chloride abstraction from the solvent (CH(2)Cl(2)) has resulted in a mixed halide system and the metal centers are square-pyramidal. Reaction of Ni(OTf)(2) with CBQ leads to the isolation of the octahedral cation [Ni(CMBQ)(2)](2+), with CMBQ [(1R,2R)-cyclohexanediamine-mono-N-(benzo[h]quinoline-2-ylmethylene)] being the partial hydrolysis product of CBQ. [Ni(CMBQ)(2)][OTf](2) crystallizes as a 1:1 mixture of P and M helical diastereomers. The coordination of NiI(2) with the (R)-BINAM derived ligands yields the anti dinuclear P-helical complexes [Ni(2)(BBQ)(μ-I)(2)I(2)] and [Ni(2)(BPQ)(μ-I)(2)I(2)]: one nickel ion is coordinated in each bidentate iminoquinoline pocket and the geometry at the metal centers is distorted square

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

    NASA Astrophysics Data System (ADS)

    Shakila, K.; Kalainathan, S.

    2015-01-01

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

  7. 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).

  8. Synthesis, characterization, and antioxidant/cytotoxic activity of new chromone Schiff base nano-complexes of Zn(II), Cu(II), Ni(II) and Co(II)

    NASA Astrophysics Data System (ADS)

    Saif, M.; El-Shafiy, Hoda F.; Mashaly, Mahmoud M.; Eid, Mohamed F.; Nabeel, A. I.; Fouad, R.

    2016-08-01

    A chromone Schiff base complexes of Zn(II) (1), Cu(II) (2), Ni(II) (3) and Co(II) (4) were successfully prepared in nano domain with crystalline or amorphous structures. The spectroscopic data revealed that the Schiff base ligand behaves as a monoanionic tridentate ligand. The metal complexes exhibited octahedral geometry. Transmission electron microscope (TEM) analysis showed that Cu(II) complex have aggregated nanospheres morphology. The obtained nano-complexes were tested as antioxidant and antitumor agents. The H2L and its Cu(II) complex (2) were found to be more potent antioxidant (IC50(H2L) = 0.93 μM; IC50(Cu(II) complex) = 1.1 μM than standard ascorbic acid (IC50 = 2.1 μM) as evaluated by DPPH• method. The H2L and its complexes (1-4) were tested for their in vitro cytotoxicity against Ehrlich Ascites Carcinoma cell line (EAC). The Cu(II) nano-complex (2) effectively inhibited EAC growth with IC50 value of 47 μM in comparison with its parent compound and other prepared complexes. The high antioxidant activity and antitumor activity of Cu(II) nano-complex (2) were attributed to their chemical structure, Cu(II) reducing capacity, and nanosize property. The toxicity test on mice showed that Zn(II) (1) and Cu(II) (2) nano-complex have lower toxicity than the standard cis-platin.

  9. Substituent effects of N4 Schiff base ligands on the formation of fluoride-bridged dicobalt(ii) complexes via B-F abstraction: structures and magnetism.

    PubMed

    Cho, Yae In; Ward, Meredith L; Rose, Michael J

    2016-09-14

    We report the synthesis of two fluoride bridged cobalt(ii) dimers - [Co(μ-F)(pnN4-PhCl)2(OH2)(MeCN)](BF4)3 (1) and [Co(μ-F)2(pnN4-PhCl)2](BF4)2 (2) - and related complexes derived from propyl-bridged N4 Schiff base plus pyridine ligands. Notably, the bridging fluoride ion(s) emanate from B-F abstraction processes on the BF4 anions in the starting salt, [Co(H2O)6](BF4)2. Two types of bridging motifs are generated - mono-bridged (μ-F) or di-bridged (μ-F)2- synthetically differentiated by the absence or presence of pyridine, respectively, during metalation. The synergistic roles of pyridine and the (ClPh)N4 ligand in promoting B-F abstraction were clarified by the isolation and crystallization of the simple tetrakis-pyridine monomeric complex [Co(py)4(MeCN)2](BF4)2 (4) [no B-F abstraction]; subsequent addition of the (ClPh)N4 ligand to 4 resulted in formation of the dimeric, di-bridged complex 2. Omission of pyridine during metalation resulted in formation of the mono-bridged dimer 1. The bulky chlorophenyl substituents were obligate for B-F abstraction, as metalation of the unsubstituted N4 ligand resulted in the non-fluoride-bridged dimer, [Co(pnN4)3](BF4)4 (3). In magnetic studies, complexes 1 (μeff = 6.24μB, 298 K) and 2 (μeff = 7.70μB, 298 K) both exhibit antiferromagnetic (AFM) coupling, but to different extents. Temperature-dependent magnetic susceptibility measurements (SQUID, 2 → 300 K) reveal that the linearity of the mono-fluoride bridge in 1 [∠Co-F-Co = 159.47(11)°] results in very strong AFM coupling (J = -14.9 cm(-1)). In contrast, the more acute Co2F2 diamond core [∠Co-F-Co = 98.8(2)°, 99.1(2)°] results in a smaller extent of AFM coupling (J = -2.97 cm(-1)). Overall, the results indicate the 'non-innocence' of the BF4 counterion in cobalt(ii) chemistry, and dimers 1 and 2 affirm the effect of the geometry of the bridging fluoride ion(s) in determining the extent of AFM coupling. PMID:27491352

  10. Substituent effects of N4 Schiff base ligands on the formation of fluoride-bridged dicobalt(ii) complexes via B-F abstraction: structures and magnetism.

    PubMed

    Cho, Yae In; Ward, Meredith L; Rose, Michael J

    2016-09-14

    We report the synthesis of two fluoride bridged cobalt(ii) dimers - [Co(μ-F)(pnN4-PhCl)2(OH2)(MeCN)](BF4)3 (1) and [Co(μ-F)2(pnN4-PhCl)2](BF4)2 (2) - and related complexes derived from propyl-bridged N4 Schiff base plus pyridine ligands. Notably, the bridging fluoride ion(s) emanate from B-F abstraction processes on the BF4 anions in the starting salt, [Co(H2O)6](BF4)2. Two types of bridging motifs are generated - mono-bridged (μ-F) or di-bridged (μ-F)2- synthetically differentiated by the absence or presence of pyridine, respectively, during metalation. The synergistic roles of pyridine and the (ClPh)N4 ligand in promoting B-F abstraction were clarified by the isolation and crystallization of the simple tetrakis-pyridine monomeric complex [Co(py)4(MeCN)2](BF4)2 (4) [no B-F abstraction]; subsequent addition of the (ClPh)N4 ligand to 4 resulted in formation of the dimeric, di-bridged complex 2. Omission of pyridine during metalation resulted in formation of the mono-bridged dimer 1. The bulky chlorophenyl substituents were obligate for B-F abstraction, as metalation of the unsubstituted N4 ligand resulted in the non-fluoride-bridged dimer, [Co(pnN4)3](BF4)4 (3). In magnetic studies, complexes 1 (μeff = 6.24μB, 298 K) and 2 (μeff = 7.70μB, 298 K) both exhibit antiferromagnetic (AFM) coupling, but to different extents. Temperature-dependent magnetic susceptibility measurements (SQUID, 2 → 300 K) reveal that the linearity of the mono-fluoride bridge in 1 [∠Co-F-Co = 159.47(11)°] results in very strong AFM coupling (J = -14.9 cm(-1)). In contrast, the more acute Co2F2 diamond core [∠Co-F-Co = 98.8(2)°, 99.1(2)°] results in a smaller extent of AFM coupling (J = -2.97 cm(-1)). Overall, the results indicate the 'non-innocence' of the BF4 counterion in cobalt(ii) chemistry, and dimers 1 and 2 affirm the effect of the geometry of the bridging fluoride ion(s) in determining the extent of AFM coupling.

  11. 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.

  12. 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

    2015-04-21

    The reaction of the dialdehyde N,N-di(α-formylpyrrolyl-α-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.

  13. Observation of an organic acid mediated spin state transition in a Co(II)-Schiff base complex: an EPR, HYSCORE, and DFT study.

    PubMed

    Vinck, Evi; Carter, Emma; Murphy, Damien M; Van Doorslaer, Sabine

    2012-08-01

    The interactions of a weak organic acid (acetic acid, HOAc) with a toluene solution of the Co(II)-Schiff base type complex, (R,R')-N,N'-bis(3,5-di-tert-butylsalicylidene)-1,2-cyclohexane-diamino Co(II) (labeled [Co(1)]), was investigated using EPR, HYSCORE, and DFT computations. This activated [Co(II)(1)] system is extremely important within the context of asymmetric catalysts (notably the hydrolytic kinetic resolution of epoxides) despite the lack of detailed structural information about the nature of the paramagnetic species present. Under anaerobic conditions, the LS [Co(II)(1)] complex with a |yz, (2)A(2)〉 ground state is converted into a low-spin (LS) and a high-spin (HS) complex in the presence of the acid. The newly formed LS state is assigned to the coordinated [Co(II)(1)]-(HOAc) complex, possessing a |z(2), (2)A(1)〉 ground state (species A; g(x) = 2.42, g(y) = 2.28, g(z) = 2.02, A(x) = 100, A(y) = 120, A(z) = 310 MHz). The newly formed HS state is assigned to an acetate coordinated [Co(II)(1)]-(OAc(-)) complex, possessing an S = 3/2 spin ground state (species B, responsible for a broad EPR signal with g ≈ 4.6). These spin ground states were confirmed with DFT calculations using the hybrid BP86 and B3LYP functionals. Under aerobic conditions, the LS and HS complexes (species A and B) are not observed; instead, a new HS complex (species C) is formed. This complex is tentatively assigned to a paramagnetic superoxo bridged dimer (AcO(-))[Co(II)(1)···O(2)(-)Co(III)(1)](HOAc), as distinct from the more common diamagnetic peroxo bridged dimers. Species C is characterized by a very broad HS EPR signal (g(x) = 5.1, g(y) = 3.9, g(z) = 2.1) and is reversibly formed by oxygenation of the LS [Co(II)(1)]-(HOAc) complex to the superoxo complex [Co(III)(1)O(2)(-)](HOAc), which subsequently forms the association complex C by interaction with the HS [Co(II)(1)](OAc(-)) species. The LS and HS complexes were also identified using other organic acids (benzoic and

  14. Observation of an organic acid mediated spin state transition in a Co(II)-Schiff base complex: an EPR, HYSCORE, and DFT study.

    PubMed

    Vinck, Evi; Carter, Emma; Murphy, Damien M; Van Doorslaer, Sabine

    2012-08-01

    The interactions of a weak organic acid (acetic acid, HOAc) with a toluene solution of the Co(II)-Schiff base type complex, (R,R')-N,N'-bis(3,5-di-tert-butylsalicylidene)-1,2-cyclohexane-diamino Co(II) (labeled [Co(1)]), was investigated using EPR, HYSCORE, and DFT computations. This activated [Co(II)(1)] system is extremely important within the context of asymmetric catalysts (notably the hydrolytic kinetic resolution of epoxides) despite the lack of detailed structural information about the nature of the paramagnetic species present. Under anaerobic conditions, the LS [Co(II)(1)] complex with a |yz, (2)A(2)〉 ground state is converted into a low-spin (LS) and a high-spin (HS) complex in the presence of the acid. The newly formed LS state is assigned to the coordinated [Co(II)(1)]-(HOAc) complex, possessing a |z(2), (2)A(1)〉 ground state (species A; g(x) = 2.42, g(y) = 2.28, g(z) = 2.02, A(x) = 100, A(y) = 120, A(z) = 310 MHz). The newly formed HS state is assigned to an acetate coordinated [Co(II)(1)]-(OAc(-)) complex, possessing an S = 3/2 spin ground state (species B, responsible for a broad EPR signal with g ≈ 4.6). These spin ground states were confirmed with DFT calculations using the hybrid BP86 and B3LYP functionals. Under aerobic conditions, the LS and HS complexes (species A and B) are not observed; instead, a new HS complex (species C) is formed. This complex is tentatively assigned to a paramagnetic superoxo bridged dimer (AcO(-))[Co(II)(1)···O(2)(-)Co(III)(1)](HOAc), as distinct from the more common diamagnetic peroxo bridged dimers. Species C is characterized by a very broad HS EPR signal (g(x) = 5.1, g(y) = 3.9, g(z) = 2.1) and is reversibly formed by oxygenation of the LS [Co(II)(1)]-(HOAc) complex to the superoxo complex [Co(III)(1)O(2)(-)](HOAc), which subsequently forms the association complex C by interaction with the HS [Co(II)(1)](OAc(-)) species. The LS and HS complexes were also identified using other organic acids (benzoic and

  15. Synthesis, characterization, and antitumor activity of three ternary dinuclear copper (II) complexes with a reduced Schiff base ligand and diimine coligands in vitro and in vivo.

    PubMed

    Jia, Lei; Xu, Jun; Zhao, Xiaolei; Shen, Shanshan; Zhou, Tao; Xu, Zhouqing; Zhu, Taofeng; Chen, Ruhua; Ma, Tieliang; Xie, Jing; Dong, Kun; Huang, Jiancui

    2016-06-01

    Three ternary copper (II) complexes containing 1,10-phenanthroline (phen, 1), dipyrido[3,2-d:2',3'-f]quinoxaline (dpq, 2) and dipyrido[3,2-a:2',3'-c]phenazine (dppz, 3), with the formulation [Cu2(NCL)2(H4PASP)]·4.5H2O (1-3) (where NCL=the diimine coligand, H4PASP=N,N'-(p-xylylene)di-2-aminosuccinic acid), were isolated and characterized. The binding of these complexes with calf thymus DNA was studied using UV-visible absorption titration, emission, and circular dichroism spectroscopy, among other methods. The changes in physicochemical properties that occurred upon binding of these complexes with DNA indicate that binding occurs primarily through intercalative interactions. Human tumor cell lines HeLa, PC3, and HepG2 were treated with the copper(II) complexes in vitro and cell survival rate was assessed by 3-(4,5-dimethyl thiazol-2yl)-2,5-diphenyltetrazolium bromide (MTT) assay and crystal violet survival assay. Flow cytometry was performed on treated cells labeled with AnnexinV/Propidium Iodide staining to determine rates of apoptosis. Western blot was performed to determine the expression levels of the apoptotic markers p53, Bax, and Bcl-2. The complexes reduced cell viability and induced apoptosis in cells of human tumor cell lines in a dose-dependent manner. In addition, using a nude mouse xenograft model, we found that the three ternary copper (II) complexes inhibited human tumor cell growth in vivo. In conclusion, these novel synthetic copper complexes have profound antitumor effects on human tumor cells and are promising therapeutic agents for human tumors.

  16. Synthesis, characterization, and antitumor activity of three ternary dinuclear copper (II) complexes with a reduced Schiff base ligand and diimine coligands in vitro and in vivo.

    PubMed

    Jia, Lei; Xu, Jun; Zhao, Xiaolei; Shen, Shanshan; Zhou, Tao; Xu, Zhouqing; Zhu, Taofeng; Chen, Ruhua; Ma, Tieliang; Xie, Jing; Dong, Kun; Huang, Jiancui

    2016-06-01

    Three ternary copper (II) complexes containing 1,10-phenanthroline (phen, 1), dipyrido[3,2-d:2',3'-f]quinoxaline (dpq, 2) and dipyrido[3,2-a:2',3'-c]phenazine (dppz, 3), with the formulation [Cu2(NCL)2(H4PASP)]·4.5H2O (1-3) (where NCL=the diimine coligand, H4PASP=N,N'-(p-xylylene)di-2-aminosuccinic acid), were isolated and characterized. The binding of these complexes with calf thymus DNA was studied using UV-visible absorption titration, emission, and circular dichroism spectroscopy, among other methods. The changes in physicochemical properties that occurred upon binding of these complexes with DNA indicate that binding occurs primarily through intercalative interactions. Human tumor cell lines HeLa, PC3, and HepG2 were treated with the copper(II) complexes in vitro and cell survival rate was assessed by 3-(4,5-dimethyl thiazol-2yl)-2,5-diphenyltetrazolium bromide (MTT) assay and crystal violet survival assay. Flow cytometry was performed on treated cells labeled with AnnexinV/Propidium Iodide staining to determine rates of apoptosis. Western blot was performed to determine the expression levels of the apoptotic markers p53, Bax, and Bcl-2. The complexes reduced cell viability and induced apoptosis in cells of human tumor cell lines in a dose-dependent manner. In addition, using a nude mouse xenograft model, we found that the three ternary copper (II) complexes inhibited human tumor cell growth in vivo. In conclusion, these novel synthetic copper complexes have profound antitumor effects on human tumor cells and are promising therapeutic agents for human tumors. PMID:26974885

  17. The relationship between the strength of hydrogen bonding and spin crossover behaviour in a series of iron(III) Schiff base complexes.

    PubMed

    Nemec, Ivan; Herchel, Radovan; Trávníček, Zdeněk

    2015-03-14

    X-ray crystal structures and magnetic properties of an isostructural series of iron(III) Schiff base complexes with the general formula [Fe(L(5))(NCX)]·Solv (where H2L(5) = N,N'-bis(2-hydroxy-naphthylidene)-1,6-diamino-4-azahexane, X = S, Solv = tetrahydrofuran, 1a; X = S, Solv = methanol and 0.5 pyrazine, 1b; X = S, Solv = butanone, 1c; Solv = N,N'-dimethylformamide, X = S (1d) or X = Se (1d'); X = S, Solv = dimethyl sulfoxide, 1e) are reported. In the crystals, the individual [Fe(L(5))(NCX)] molecules are connected through weak C-H···O, C-H···π or C-H···S non-covalent contacts into 2D supramolecular networks, while the guest-solvent (Solv) molecules are trapped in the cavities between two adjacent layers, which are furthermore stabilized by N-H···O hydrogen bonds connecting the Solv oxygen atom with the amine group of the [Fe(L(5))(NCX)] molecule, with the N···O distances varying from 2.921(6) Å (in 1d') to 3.295(2) Å (in 1a). The magnetic properties of the complexes were tuned by the different Solv molecules and as a result of this, four new spin crossover (SCO) compounds with cooperative spin transitions are reported, which are accompanied by thermal hysteresis in two cases (1d and 1e): , T1/2 = 84 K; 1d, T1/2↓ = 232 K, T1/2↑ = 235 K and 1e, T1/2↓ = 127 K, T1/2↑ = 138 K. The role of the N-H···O hydrogen bonding in the occurrence and tuning of SCO was also computationally studied using a topological analysis, and also by evaluation of non-covalent interaction (NCI) indexes. Both theoretical approaches showed a clear relationship between the strength of the N-H···O hydrogen bonds and T1/2, as already inferred from X-ray structural and magnetic data. PMID:25645590

  18. Evaluation of DNA Binding, Cleavage, and Cytotoxic Activity of Cu(II), Co(II), and Ni(II) Schiff Base Complexes of 1-Phenylindoline-2,3-dione with Isonicotinohydrazide

    PubMed Central

    Gomathi, Ramadoss; Ramu, Andy; Murugan, Athiappan

    2014-01-01

    One new series of Cu(II), Co(II), and Ni(II) Schiff base complexes was prepared through the condensation reaction between 1-phenylindoline-2,3-dione with isonicotinohydrazide followed by metalation, respectively. The Schiff base ligand(L), (E)-N′-(2-oxo-1-phenylindolin-3-lidene)isonicotinohydrazide, and its complexes were found soluble in DMF and DMSO solvents and characterized by using the modern analytical and spectral techniques such as elemental analysis, conductivity, magnetic moments, IR, NMR, UV-visible, Mass, CV, and EPR. The elemental analysis data of ligand and their complexes were well agreed with their calculated values in which metal and ligand stoichiometry ratio 1 : 2 was noted. Molar conductance values indicated that all the complexes were found to be nonelectrolytes. All the complexes showed octahedral geometry around the central metal ions. Herein, we better characterized DNA binding with the complexes by UV-visible and CD spectroscopy and cyclic voltammetry techniques. The DNA cleavage experiments were carried out by Agarose gel electrophoresis method and the cytotoxicity experiments by MTT assay method. Based on the DNA binding, cleavage, and cytotoxicity studies, Cu and Ni complexes were found to be good anticancer agents against AGS-human gastric cancer cell line. PMID:24744691

  19. Synthesis and Characterization of Cr(III), Mn(III), Fe(III), VO(IV), Zr(IV) and UO2(VI) Complexes of Schiff Base Derived from Isonicotinoyl Hydrazone

    PubMed Central

    Gawande, Pranita U.; Mandlik, P. R.; Aswar, A. S.

    2015-01-01

    2-hydroxy-5-chloro-3-nitroacetophenone isonicotinoyl hydrazone as a Schiff base ligand and its complexes with Cr(III), Mn(III), Fe(III), VO(IV), Zr(IV) and UO2(VI) metal ions have been synthesized. The ligands as well as their metal complexes were well characterized using various physicochemical techniques such as elemental analyses, molar conductance measurements, magnetic measurements, thermal analysis, electronic and IR spectral studies. On the basis of these studies, square pyramidal stereochemistry for Mn(III) and VO(IV) complexes while octahedral stereochemistry for all the other complexes have been suggested. The complexes were found to be stable up to 60-70° and thermal decomposition of the complexes ended with respective metal oxide as a final product. The thermal data have been analyzed for kinetic parameters using Broido and Horowitz-Metzger methods. The synthesized Schiff base ligand and its complexes were also tested for their antimicrobial activity using various microorganisms. PMID:26664052

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

    PubMed

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

    2015-07-20

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

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

    NASA Astrophysics Data System (ADS)

    Karaoğlu, Kaan; Baran, Talat; Değirmencioğlu, İsmail; Serbest, Kerim

    2011-09-01

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

  2. Apoptotic effect of novel Schiff Based CdCl2(C14H21N3O2) complex is mediated via activation of the mitochondrial pathway in colon cancer cells

    PubMed Central

    Hajrezaie, Maryam; Paydar, Mohammadjavad; Looi, Chung Yeng; Moghadamtousi, Soheil Zorofchian; Hassandarvish, Pouya; Salga, Muhammad Saleh; Karimian, Hamed; Shams, Keivan; Zahedifard, Maryam; Majid, Nazia Abdul; Ali, Hapipah Mohd; Abdulla, Mahmood Ameen

    2015-01-01

    The development of metal-based agents has had a tremendous role in the present progress in cancer chemotherapy. One well-known example of metal-based agents is Schiff based metal complexes, which hold great promise for cancer therapy. Based on the potential of Schiff based complexes for the induction of apoptosis, this study aimed to examine the cytotoxic and apoptotic activity of a CdCl2(C14H21N3O2) complex on HT-29 cells. The complex exerted a potent suppressive effect on HT-29 cells with an IC50 value of 2.57 ± 0.39 after 72 h of treatment. The collapse of the mitochondrial membrane potential and the elevated release of cytochrome c from the mitochondria to the cytosol indicate the involvement of the intrinsic pathway in the induction of apoptosis. The role of the mitochondria-dependent apoptotic pathway was further proved by the significant activation of the initiator caspase-9 and the executioner caspases-3 and -7. In addition, the activation of caspase-8, which is associated with the suppression of NF-κB translocation to the nucleus, also revealed the involvement of the extrinsic pathway in the induced apoptosis. The results suggest that the CdCl2(C14H21N3O2) complex is able to induce the apoptosis of colon cancer cells and is a potential candidate for future cancer studies. PMID:25764970

  3. 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

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

    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 μ 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

  4. 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 μg/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

  5. 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

    NASA Astrophysics Data System (ADS)

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

    2015-04-01

    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, 1H NMR, magnetic measurements, and thermal analysis. Cyclic voltammetry and biological activity were also investigated.

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

    PubMed

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

    2013-09-01

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

  7. 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.

  8. Facile luminescent tuning of Zn(II)/Hg(II) complexes based on flexible, semi-rigid and rigid polydentate Schiff bases from blue to green to red: structural, photophysics, electrochemistry and theoretical calculations studies.

    PubMed

    Wang, Xin-Ming; Chen, Shuo; Fan, Rui-Qing; Zhang, Fu-Qiang; Yang, Yu-Lin

    2015-05-01

    The photophysical properties of Zn(II)/Hg(II) Schiff base complexes could be fine and predictably tuned over a wide range of wavelengths by changing the ligand structures. A new series of polydentate Schiff base-type ligands, N,N'-bis(2-pyridinylethylidene)R(3)-1,2-diamine (), which contain a flexible, semi-rigid or rigid group (R(3) = butyl, cyclohexane, tolyl and phenylene), has been designed and employed for synthetizing new mononuclear or binuclear trans Zn(II)/Hg(II) complexes with a general formula of [M()Cl2] ( = N,N'-bis(2-pyridinylethylidene)phenylene-1,2-diamine, M = Zn, ; M = Hg, ), [M()Cl2] ( = N,N'-bis(2-pyridinylethylidene)toluene-3,4-diamine, M = Zn, ; M = Hg, ), [M2()Cl4]·nCH2Cl2 ( = N,N'-bis(2-pyridinylmethylene)cyclohexane-1,2-diamine, M = Zn, n = 0, ; M = Hg, n = 1, ), [M2()Cl4]·nCH3OH ( = N,N'-bis(2-pyridinylethylidene)cyclohexane-1,2-diamine, M = Zn, n = 1, ; M = Hg, n = 0, ), [M2()Cl4] ( = N,N'-bis(3-methoxy-2-pyridinylmethylene)-cyclohexane-1,2-diamine, M = Zn, ; M = Hg, ), [M2()Cl4]·nCH3CN ( = N,N'-bis(3-methoxy-2-pyridinylmethylene)butane-1,4-diamine, M = Zn, n = 4, ; M = Hg, n = 0, ). All the ligands and complexes have been characterized by elemental analyses, IR spectra, and (1)H NMR spectra. Twelve structures of , , , , , and crystallized in three different conditions are further determined by single-crystal X-ray diffraction analyses. Their properties are fully characterized by UV-vis and fluorescence spectra both in solution and the solid state at room temperature. The luminescence color of these Zn(II)/Hg(II) Schiff base complexes could be tuned from blue to green to red (429-639 nm for , 434-627 nm for ) in solution by changing the ligand conjugated systems from flexibile () to semi-rigid () to rigid (). The spectra of the free Schiff bases are centered around 402-571 nm, which are perturbed upon the coordination to the Zn(II)/Hg(II) ion. Both the electrochemical data and TD-DFT calculations show that the HOMO-LUMO band gap from

  9. 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.

  10. Electrochemistry of copper(II) induced complexes in mycorrhizal maize plant tissues.

    PubMed

    Zitka, Ondrej; Merlos, Miguel-Angel; Adam, Vojtech; Ferrol, Nuria; Pohanka, Miroslav; Hubalek, Jaromir; Zehnalek, Josef; Trnkova, Libuse; Kizek, Rene

    2012-02-15

    Aim of the present paper was to study the electrochemical behavior of copper(II) induced complexes in extracts obtained from mycorrhizal and non-mycorrhizal maize (Zea mays L.) plants grown at two concentrations of copper(II): physiological (31.7 ng/mL) and toxic (317 μg/mL). Protein content was determined in the plant extracts and, after dilution to proper concentration, various concentrations of copper(II) ions (0, 100, 200 and 400 μg/mL) were added and incubated for 1h at 37°C. Further, the extracts were analyzed using flow injection analysis with electrochemical detection. The hydrodynamic voltammogram (HDV), which was obtained for each sample, indicated the complex creation. Steepness of measured dependencies was as follows: control 317 μg/mL of coppercopper(II) ions to upper parts of a plant by means of adsorbing of copper(II) in roots. Rapid complex formation was determined under applied potentials 300, 500 and 600 mV during the measuring HDVs. It was also verified that mycorrhizal colonization reduced root to shoot translocation of Cu(II) ions.

  11. 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.

  12. Complexation of copper(II) with chitosan nanogels: toward control of microbial growth.

    PubMed

    Brunel, Fabrice; El Gueddari, Nour Eddine; Moerschbacher, Bruno M

    2013-02-15

    Pure chitosan nanogels were produced, used to adsorb copper(II), and their antimicrobial activities were assessed. The complexation of copper(II) with chitosan solutions and dispersions was studied using UV-vis spectrometry. The adsorption capacity of chitosan nanogels was comparable to that of chitosan solutions, but copper(II)-loaded nanogels were more stable (i.e. no flocculation was observed while chitosan solutions showed macroscopic gelation at high copper concentration) and were easier to handle (i.e. no increase in viscosity). Adsorption isotherms of copper(II) onto chitosan were established and the impact of the pH on copper(II) release was investigated. The formation of a copper(II)-chitosan complex strongly depended on pH. Hence, release of copper(II) can be triggered by a decrease in pH (i.e. the protonation of chitosan amino groups). Furthermore, chitosan nanohydrogels were shown to be a suitable substrate for chitosan hydrolytic enzymes. Finally, a strong synergistic effect between chitosan and copper in inhibiting Fusarium graminearum growth was observed. The suitability of these copper(II)-chitosan colloids as a new generation of copper-based bio-pesticides, i.e. as a bio-compatible, bio-active and pH-sensitive delivery system, is discussed.

  13. A new hydrogen-bonded pseudo-dimer Mn(III) Schiff base complex. The synthesis, X-ray structure and spectroscopic studies

    NASA Astrophysics Data System (ADS)

    Gungor, Elif; Kara, Hulya

    2011-11-01

    A new hydrogen-bonded pseudo-dimer, [Mn(III)L1(CH 3CH 2OH)] 2(ClO 4) ( 1) (L1 = N, N'-bis(2-hydroxy-1-naphthalidenato)-1,2-diaminopropane) has been synthesized and characterized by UV-vis, IR, elemental analysis and crystal structure analysis. The single crystal X-ray diffraction reveals that the structure affords an elongated octahedral MnN 2O 4 coordination environment, geometry with the four donor atoms of the tetradentate Schiff base in the equatorial plane and with two ethanol molecule in axial positions with Mn-O = 2.265(2) and 2.266(2) Å.

  14. 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.

    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.

  15. Synthesis, crystal structures, and biological evaluation of Cu(II) and Zn(II) complexes of 2-benzoylpyridine Schiff bases derived from S-methyl- and S-phenyldithiocarbazates.

    PubMed

    Li, Ming Xue; Zhang, Li Zhi; Chen, Chun Ling; Niu, Jing Yang; Ji, Bian Sheng

    2012-01-01

    Two NNS tridentate Schiff base ligands of 2-benzoylpyridine S-methyldithiocarbazate (HL(1)) and 2-benzoylpyridine S-phenyldithiocarbazate (HL(2)) and their transition metal complexes [Cu(2)(L(1))(2)(CH(3)COO)](ClO(4)) (1), [Zn(2)(L(1))(2)(ClO(4))(2)] (2), [Zn(L(2))(2)](3) have been prepared and characterized by elemental analysis, IR, MS, NMR and single-crystal X-ray diffraction studies. In the solid state, each of two Schiff bases remains in its thione tautomeric form with the thione sulfur atom trans to the azomethine nitrogen atom. Under similar prepared conditions, three new complexes showed distinctly different coordination modes depending on their coordinating preferences. Each copper atom in S-bridged dinuclear complex [Cu(2)(L(1))(2)(CH(3)COO)](ClO(4)) (1) is surrounded by five donor atoms in a square-pyramidal fashion (4+1). [Zn(2)(L(1))(2)(ClO(4))(2)] (2) is a dimer in which each zinc atom adopts a seven-coordinate distorted pentagonal bipyramidal geometry, while mononuclear [Zn(L(2))(2)] (3) has octahedral coordination geometry. Biological studies, carried out in vitro against selected bacteria, fungi, and K562 leukaemia cell line, respectively, have shown that different substituted groups attached at the dithiocarbazate moieties and metals showed distinctive differences in the biological property. Zinc(II) complexes 2 and 3 could distinguish K562 leukaemia cell line from normal hepatocyte QSG7701 cell line. Effect of the title compounds on Mitochondria membrane potential (MMP) and PI-associated fluorescence intensity in K562 leukaemia cell line are also studied. The title compounds may exert their cytotoxicity activity via induced loss of MMP. PMID:22112848

  16. 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.

  17. A new oxovanadium(IV) complex containing an O,N-bidentate Schiff base ligand: Synthesis at ambient temperature, characterization, crystal structure and catalytic performance in selective oxidation of sulfides to sulfones using H2O2 under solvent-free conditions

    NASA Astrophysics Data System (ADS)

    Menati, Saeid; Rudbari, Hadi Amiri; Khorshidifard, Mahsa; Jalilian, Fariba

    2016-01-01

    A new bidentate ON Schiff base ligand, HL, was synthesized by simple condensation reaction of isopropylamine and salicylaldehyde. Then by reaction of HL and VO(acac)2 in the ratio of 2:1 at ambient temperature, a new oxovanadium(IV) Schiff base complex, VOL2, was synthesized. The Schiff base ligand and its oxovanadium(IV) complex were characterized by elemental analyses, FT-IR, 1H NMR, 13C NMR and UV-visible spectroscopies. The crystal structure of oxovanadium(IV) complex, VOL2, was also determined by single crystal X-ray analysis. The vanadium center in this structure is coordinated to two bidentate Schiff base ligands with the two nitrogen and two phenolate oxygen atoms in equatorial positions and one oxo oxygen in the axial position to complete the distorted trigonal bipyramidal N2O3 coordination sphere. Catalytic performance of the VOL2 complex was studied in the selective oxidation of thioanisole with the green oxidant 35% aqueous H2O2 under solvent-free conditions and under organic solvents (EtOH, CHCl3, CH2Cl2, DMF, CH3CN, EtOAc) as a model. Due to better catalytic performance of the VOL2 complex under solvent-free conditions, this complex used for the oxidation of the different sulfides to the corresponding sulfones under solvent-free conditions. The use of hydrogen peroxide as oxidant and the absence of solvent makes these reactions interesting from environmental and economic points of view.

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

    NASA Astrophysics Data System (ADS)

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

    2015-06-01

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

  19. Copper(II) complexes with tridentate N-(benzoyl)-N‧-(salicylidine)-hydrazine and monodentate N-heterocycles: Investigations of intermolecular interactions in the solid state

    NASA Astrophysics Data System (ADS)

    Das, Sunirban; Pal, Samudranil

    2005-10-01

    Ternary copper(II) complexes having the general formula [Cu(bhs)(hc)], with a tridentate Schiff base, N-(benzoyl)- N'-(salicylidine)-hydrazine (H 2bhs) and monodentate N-heterocycles (hc=3,5-dimethylpyrazole, pyrazole, imidazole, and pyridine), are described. The complexes were characterized by elemental analysis, spectroscopic and cryomagnetic measurements and X-ray crystallography. Analytical data, infrared and electronic spectral features and molar conductivity values are consistent with the proposed molecular formula and the +2 oxidation state of the metal ion in these complexes. Cryomagnetic and EPR spectral measurements showed weak antiferromagnetic spin-exchange in all four complexes. In each complex, the metal ion is in N 2O 2 square-plane constituted by the phenolate-O, the imine-N, and the deprotonated amide-O donor bhs 2- and the sp 2 N-donor neutral heterocycle. In the solid state, the complexes having 3,5-dimethylpyrazole, imidazole, and pyridine as the heterocyclic ligand, exist as centrosymmetric dimeric species due to weak apical coordination of the metal bound phenolate-O. On the other hand, only one of the two molecules present in the asymmetric unit of the complex containing pyrazole forms the centrosymmetric dimeric species due to weak apical coordination of the metal bound amide-O. In the crystal lattice, intermolecular π-π, C-H⋯π, C-H⋯N, O-H⋯N and N-H⋯O interactions involving the complex and the solvent molecules lead to one- and two-dimensional supramolecular structures.

  20. In vitro DNA binding, pBR322 plasmid cleavage and molecular modeling study of chiral benzothiazole Schiff-base-valine Cu(II) and Zn(II) complexes to evaluate their enantiomeric biological disposition for molecular target DNA.

    PubMed

    Alizadeh, Rahman; Afzal, Mohd; Arjmand, Farukh

    2014-10-15

    Bicyclic heterocyclic compounds viz. benzothiazoles are key components of deoxyribonucleic acid (DNA) molecules and participate directly in the encoding of genetic information. Benzothiazoles, therefore, represent a potent and selective class of antitumor compounds. The design and synthesis of chiral antitumor chemotherapeutic agents of Cu(II) and Zn(II), L- and -D benzothiazole Schiff base-valine complexes 1a &b and 2a &b, respectively were carried out and thoroughly characterized by spectroscopic and analytical techniques. Interaction of 1a and b and 2a and b with CT DNA by employing UV-vis, florescence, circular dichroic methods and cleavage studies of 1a with pBR322 plasmid, molecular docking were done in order to demonstrate their enantiomeric disposition toward the molecular drug target DNA. Interestingly, these studies unambiguously demonstrated the greater potency of L-enantiomer in comparison to D-enantiomer.

  1. In vitro DNA binding, pBR322 plasmid cleavage and molecular modeling study of chiral benzothiazole Schiff-base-valine Cu(II) and Zn(II) complexes to evaluate their enantiomeric biological disposition for molecular target DNA

    NASA Astrophysics Data System (ADS)

    Alizadeh, Rahman; Afzal, Mohd; Arjmand, Farukh

    2014-10-01

    Bicyclic heterocyclic compounds viz. benzothiazoles are key components of deoxyribonucleic acid (DNA) molecules and participate directly in the encoding of genetic information. Benzothiazoles, therefore, represent a potent and selective class of antitumor compounds. The design and synthesis of chiral antitumor chemotherapeutic agents of Cu(II) and Zn(II), L- and -D benzothiazole Schiff base-valine complexes 1a &b and 2a &b, respectively were carried out and thoroughly characterized by spectroscopic and analytical techniques. Interaction of 1a and b and 2a and b with CT DNA by employing UV-vis, florescence, circular dichroic methods and cleavage studies of 1a with pBR322 plasmid, molecular docking were done in order to demonstrate their enantiomeric disposition toward the molecular drug target DNA. Interestingly, these studies unambiguously demonstrated the greater potency of L-enantiomer in comparison to D-enantiomer.