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1

Copper(II) Schiff-base complexes and apoglobin stability  

Microsoft Academic Search

N,N?-Propylene-bis-(N-salicylidene)copper(II) (Cu(Salprn)) explicitly stabilizes apomyoglobin. The optical spectrum of this copper(II) Schiff-base complex of apomyoglobin arises from the electronic excitations of ?*-O-Salprn?dx2-y2 and N-Salprn?dx2-y2. Shifts of these transitions with respect to those of the parent complex may be a consequence of hydrophobic solvatochromism or binding of an additional ligand. ESR parameters imply no change in the identity of the first

Joseph J. Stephanos; Leia M. Jackson; Anthony W. Addison

1999-01-01

2

Electrochemical and spectroelectrochemical properties of copper(II) Schiff-base complexes  

Microsoft Academic Search

The electrochemical behaviour of several copper(II) complexes with Schiff-base ligands containing pyrrole groups has been investigated in aprotic solvents by cyclic voltammetry and spectroelectrochemistry. Electrochemical oxidation of copper(II) complexes in acetonitrile produces conducting polymeric films at the electrode surface. The modified electrodes were electrochemically and spectrochemically characterized and their electrocatalytical properties have been examined.

J Losada; I del Peso; L Beyer

2001-01-01

3

New antiferromagnetic copper(II) complexes with some dibasic tridentate ONS donor Schiff bases  

Microsoft Academic Search

Summary The syntheses of new copper(II) complexes of Schiff bases derived from salicylaldehyde, 5-chlorosalicylaldehyde, 5-bromosalicylaldehyde, 4-methoxysalicylaldehyde, 5-methoxysalicylaldehyde and 3-aminothiophenol are reported. The Schiff bases coordinate through O, N and S as tridentate dibasic ligands. The complexes, which are characterised by elemental analysis, i.r. and electronic spectra and magnetic susceptibility measurements are insoluble in common solvents and decompose above 250° without

Arun Syamal

1980-01-01

4

Electrochemical behaviour of the complexes of copper(II) with a Schiff base compartmental ligand  

Microsoft Academic Search

The ethylenediamine Schiff base derivative ofo-acetoacetylphenol, H4aapen, is a ligand able to form both mononuclear and dinuclear complexes with copper(II) ion. Mononuclear positional isomers can be obtained, having the copper in the O2O2 site and in the N2O2 site. The electrochemistry of these copper(II) complexes in dimethylsulfoxide shows that the two positional isomers are reduced at different potentials through an

Piero Zanello; Pietro Alessandro Vigato; Gian Antonio Mazzocchin

1982-01-01

5

Dinuclear Schiff-base copper(II) complexes with various bridging groups  

Microsoft Academic Search

Three new centrosymmetric dinuclear copper(II) complexes, [Cu2Cl2(L)2] (1), [Cu2(?1,3-NCS)2(L)2] (2), and [Cu2(?1,1-N3)2(L)2] (3), where L, L, and L are the deprotonated forms of the Schiff bases 1-[(2-propylaminoethylimino)methyl]naphthalen-2-ol (HL), 1-[(3-methylaminopropylimino)methyl]naphthalen-2-ol (HL), and 2-[(2-isopropylaminoethylimino)methyl]phenol (HL), respectively, have been prepared and characterized by elemental analysis, IR spectra, and single-crystal X-ray crystallography. Each Cu is coordinated by the three donors of the Schiff bases

Dong-Mei Xian; Zhong-Lu You; Mei Zhang; Peng Hou; Xiao-Hui Li

2011-01-01

6

Investigations on the Liquid Crystalline Phase of Schiff's Base Complexes of Copper(II) and Their Corresponding Ligands  

Microsoft Academic Search

Some new liquid crystalline Schiff's base complexes with copper(II) have been prepared. Microscopic observations and D.S.C. measurements reveal broad nematic mesophases. X-ray investigations on magnetically oriented samples confirm the nematic mesophase and indicate a cybotactic one.Anisotropic magnetic susceptibility data of a mixture of Schiff's base complexes of copper(II) are presented. An orientation with the longitudinal axis parallel to the magnetic

Bettina Borchers; Wolfgang Haase

1991-01-01

7

Synthesis, Crystal Structures and Antibacterial Activities of Two Schiff Base Copper(II) Complexes  

Microsoft Academic Search

Two new mononuclear Schiff base copper(II) complexes, [CuBr2L] (1) and [CuBr(NCS)L] (2), where L=N,N?dimethyl?N??(1?pyridinylmethylidene)propane?1,3?diamine, have been obtained from a similar synthetic procedure. The complexes were characterized by elemental analyses and single crystal X?ray diffraction. In 1, the copper(II) ion is five?coordinated in a distorted square?pyramidal configuration, with three N atoms of L and one terminal Br atom defining the basal

2006-01-01

8

Epoxidation of styrene with iodosylbenzene in the presence of copper(II) Schiff-base complexes  

Microsoft Academic Search

Copper(II) complexes with salen Schiff-base ligands derived from ethylenediamine or (S,S)-1,2-diphenylethylenediamine and salicylaldehyde or 5-methoxy, 5-bromo and 5-nitrosalicylaldehyde have been tested as catalysts for the epoxidation of styrene with iodosylbenzene, in dichoromethane as a solvent. The reactions were followed by gas chromatographic analysis and mass spectrometry. Catalytic activities were found to be dependent upon both the Lewis acidity of the

Santiago Zolezzi; Evgenia Spodine; Antonio Decinti

2003-01-01

9

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

PubMed

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

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

2014-12-10

10

New acyclic Schiff-base copper(II) complexes and their electrochemical, catalytic, and antimicrobial studies  

Microsoft Academic Search

A new series of acyclic mononuclear copper(II) complexes have been prepared by Schiff-base condensation derived from 5-methylsalicylaldehyde, diethylenetriamine, tris(2-aminoethyl) amine, triethylenetetramine, N,N-bis(3-aminopropyl)ethylene diamine, N,N-bis(aminopropyl) piperazine, and copper perchlorate. All the complexes were characterized by elemental and spectral analyses. Electronic spectra of the complexes show a d–d transition in the range 500–800?nm, electrochemical studies of the complexes show irreversible one-electron-reduction process

A. Vijayaraj; R. Prabu; R. Suresh; C. Sivaraj; N. Raaman; V. Narayanan

2011-01-01

11

Tridentate (NNO) Schiff-base copper(II) complex: synthesis, crystal structure, and magnetic study  

Microsoft Academic Search

A new azido adduct of a tridentate Schiff-base copper(II) complex has been synthesized and characterized structurally and magnetically. X-ray single crystal structure analysis reveals that the asymmetric unit of [Cu2(L)2(µ1,1-N3)2][Cu(L)(N3)] (1) [HL = 1-(N-ortho-hydroxyacetophenimine)-2,2-diethyl-aminoethane] has two independent moieties. One of these forms a dimer, containing end-on azido bridges, with its center of inversion related equivalents. The complex crystallizes in monoclinic

Chandan Adhikary; Rupam Sen; Gabriele Bocelli; Andrea Cantoni; Massimo Solzi; Siddhartha Chaudhuri; Subratanath Koner

2009-01-01

12

Synthesis and characterization of copper(II) Schiff base complexes derived from salicylaldehyde and glycylglycylglycine  

Microsoft Academic Search

Two copper(II) tripeptide Schiff base complexes: [Mg(H2O)6][CuL]2·3.5H2O (1) and [Cd(H2O)4(CuL)2]·3.5H2O (2) (H3L=N-salicylideneglycylglycylglycine) have been synthesized and structurally characterized. Single crystal X-ray diffraction analyses showed that the copper atom exhibits square-planar geometry, with the chelating ONNO atoms of the deprotonated Schiff base ligand(L) in the basal plane. In 1, the anions [CuL]? and cations [Mg(H2O)6]2+ are stacked in well-separated columns along

Wen-Long Liu; Yang Zou; Chun-Lin Ni; Zhao-Ping Ni; Yi-Zhi Li; Yuan-Gen Yao; Qing-Jin Meng

2004-01-01

13

Synthesis, crystal structure and nuclease activity of a Schiff base copper(II) complex  

Microsoft Academic Search

A new Schiff base copper(II) complex, Cu(o-VANAHE)2 (o-VANAHE=2-(o-vanillinamino)-1-hydroxyethane), has been synthesized and characterized. Single crystal X-ray diffraction results suggest that this complex structure belongs to triclinic crystal system, space group P1¯ with the following crystallographic parameters: a=8.819(4)Å, b=10.794(5)Å, c=11.350(5)Å, ?=70.262(6)°, ?=70.816(6)°, ?=78.360(6)°, V=955.4(7)Å3, Z=2, Dc=1.571 Mg·m?3, and the final R1=0.0393, wR2=0.0994 for the observed reflections 2620(I>2?(I)). The molecular geometry is

Lian-Zhi Li; Chao Zhao; Tao Xu; Hai-Wei Ji; Yan-Hong Yu; Guang-Qiang Guo; Hui Chao

2005-01-01

14

Synthesis and solid state structures of two new copper(II) complexes of Schiff bases derived from furfuryl and tetrahydrofurfurylamine  

Microsoft Academic Search

Two Schiff base copper(II) complexes, bis(N-furfurylsalicylaldiminato)copper(II) (I) and bis(N-tetrahydrofurfurylsalicylaldiminato)copper(II) (II), were synthesized and their solid state structures were determined by X-ray crystallography. Complex I has a square planar geometry. In contrast, complex II displays a distorted square planar geometry. Thus, the geometry around copper in the solid state structures of I and II is determined by a combination of steric

W. Chen; P. Miao; Y. G. Li; H. L. Zhu; Q. F. Zeng

2010-01-01

15

Synthesis, Characterization and Anticancer Activity of L-Alanine Schiff Base Complexes of Copper(II), Zinc(II), Nickel(II) and Cobalt(II)  

Microsoft Academic Search

A new series of copper(II), zinc(II), nickel(II) and cobalt(II) complexes with the Schiff base derived from 4-hydroxysalicylaldehyde and L-alanine has been synthesized. These compounds have been characterized by elemental analyses, thermoanalyses, conductivity measurements, infrared and electronic spectra. The Schiff base ligand and its zinc(II) complex have been further identified by H NMR. The results suggest that the Schiff base acts

Wu Zishen; Gui Ziqi; Yen Zhenhuan

1990-01-01

16

Syntheses, characterization, redox behavior and Lewis acidity of chiral nickel(II) and copper(II) Schiff base complexes  

Microsoft Academic Search

Chiral nickel(II) and copper(II) Schiff base complexes with [N2O2] coordination derived from (1R.2R)- and (1S.2S)-1,2-diamino- cyclohexane were prepared and characterized by 1H, 13C NMR, IR and mass spectroscopy and polarimetric measurement in the case of the ligands. Cyclovoltammetric and spectrophotometric measurements revealed that the redox behavior and the Lewis acidity are influenced strongly by the substituents of the ligand. Substituents

Ernst-G. Jäger; Kerstin Schuhmann; Herlmar Görls

1997-01-01

17

Huge Antiferromagnetic Exchange Interactions in Newly Reported Copper(ii) Complex of the Antiprine Schiff Base of 3-FORMYLSALICYLIC Acid  

NASA Astrophysics Data System (ADS)

This study reports the magnetic properties of newly reported copper(II) complex of the antiprine Schiff base of 3-formylsalicylic acid. Although the separation of Cu centers and the bridge angle is not known, from the magnetic analysis it is suggested that there are strong antiferromagnetic interactions between the metal centers in dimeric units. It is also suggested that the system becomes demagnetized below a certain temperature.

Bayri, Ali

18

Copper(II) selective electrochemical sensor based on Schiff Base complexes  

Microsoft Academic Search

Plasticized membranes using Schiff Base complexes, derived from 2,3-diaminopyridine and o-vanilin have been prepared and explored as Cu2+-selective sensors. Effect of various plasticizers viz., dibutyl phthalate (DBP), dioctylphthalate (DOP), chloronaphthalene (CN), tri-n-butylphosphate (TBP) etc. and anion excluder, sodium tetraphenylborate (NaTPB) was studied in detail and improved performance was observed at several instances. Optimum performance was observed with Schiff Base (B)

Lok P. Singh; Jitendra M. Bhatnagar

2004-01-01

19

Polymetallic complexes: Part VI. Schiff base complexes of cobalt(II), copper(II), nickel(II), zinc(II), cadmium(II) and mercury(II)  

Microsoft Academic Search

The doubly bidentate ON-NO donor Schiff base, prepared from salicylaldehyde and 4,4'-diaminodiphenylmethane forms complexes with 1:1 metal: ligand stoichiometric ratios. The cobalt(II), copper(II) and nickel(II) complexes exhibit subnormal magnetic moments. All the six complexes possess high melting points and are sparingly soluble in common organic solvents. A dinuclear octahedral structure is proposed for the cobalt(II), copper(II), nickel(II) and zinc(II) complexes

Bipin B. Mahapatra; Debendra Panda

1984-01-01

20

Synthesis, characterization, and thermal decomposition of fluorinated salicylaldehyde Schiff base derivatives (salen) and their complexes with copper(II)  

Microsoft Academic Search

Trifluoromethoxy functionalized copper(II) Schiff base complexes N,N?-bis(5-trifluoromethoxysalicylaldehyde)cyclohexanediiminatodiaquacopper(II) and N,N?-bis(5-trifluoromethoxysalicylaldehyde)phenylenediiminatocopper(II) were synthesized and characterized. Thermal decompositions\\u000a of the synthesized complexes were studied by thermogravimetry in order to evaluate their thermal stability and thermal decomposition\\u000a pathways. Three similar decomposition steps occurred for the two copper complexes. Mass losses and evolved gasses were characterized\\u000a by TG\\/DTA-MS. Kinetic parameters were calculated and the results

Göktürk Avsar; Hüseyin Altinel; Mustafa Kemal Yilmaz; Bilgehan Guzel

2010-01-01

21

Copper(II) complexes with chiral reduced Schiff bases: Helical self-assembly via intermolecular C–H?O interactions  

Microsoft Academic Search

Copper(II) complexes having the general formula [Cu(Ln)2] with the N,O-donor reduced Schiff bases N-(2-hydroxy-5-X-benzyl)-(R)-?-methylbenzylamine and N-(2-hydroxy-5-X-benzyl)-(S)-?-methylbenzylamine (X=Cl and Br) (HLn) are described. These chiral complexes crystallize in the noncentrosymmetric P212121 (X=Cl) and P21 (X=Br) space groups. In each case, self-assembly via intermolecular C–H?O interaction leads to a supramolecular helical superstructure.

Vamsee Krishna Muppidi; Sunirban Das; Pallepogu Raghavaiah; Samudranil Pal

2007-01-01

22

Nickel(II) and copper(II) complexes of unsymmetrical tetradentate reduced Schiff base ligands  

Microsoft Academic Search

Two new reduced Schiff base ligands, [HL1=4-{2-[(pyridin-2-ylmethyl)-amino]-ethylimino}-pentan-2-one and HL2=4-[2-(1-pyridin-2-yl-ethylamino)-ethylimino]-pentan-2-one] have been prepared by reduction of the corresponding tetradentate unsymmetrical Schiff bases derived from 1:1: 1 condensation of 1,2-ethanediamine, acetylacetone and pyridine-2-carboxaldehyde\\/2-acetyl pyridine. Four complexes, [Ni(L1)]ClO4 (1), [Cu(L1)]ClO4 (2), [Ni(L2)]ClO4 (3), and [Cu(L2)]ClO4 (4) with these two reduced Schiff base ligands have been synthesized and structurally characterized by X-ray crystallography. The

Apurba Biswas; Michael G. B. Drew; Ashutosh Ghosh

2010-01-01

23

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

Microsoft Academic Search

Twelve homo- and hetero-nuclear copper(II) complexes of tetradentate Schiff base ligands containing N4 donor sets have been prepared by employing several steps. The characterization and nature of bonding of the complexes have been deduced from elemental analysis, FT-IR, molar conductivity, magnetic moment measurements and thermal analysis. The three Schiff base ligands were further identified using 1H and 13C NMR spectra.

Bülent Dede; Fatma Karipcin; Mustafa Cengiz

2009-01-01

24

The Interaction of Nickel(II) and Copper(II) Schiff Base Complexes with Diorganotin(IV) Dichlorides in Acetonitrile: A Thermodynamic Study  

Microsoft Academic Search

Adduct formation of nickel(II) and copper(II) Schiff base complexes, (NiL) and (CuL), as donors with diorganotin(IV) dichlorides as acceptors has been investigated spectrophotometrically, in acetonitrile. L is ?,??-Me2-salen, N,N -ethylenebis(?-methylsalicylideneiminate) (1), ?,??-Me2-salpn, N,N -1,2-propylenebis(?-methylsalicylideneiminate) (2), ?,??-Ph2-salen, N,N -ethylenebis(?-phenylsalicylideneiminate) (3), and ?,??-Ph2-salpn, N,N -1,2-propylenebis(?-phenylsalicylidene- iminate) (4). The trend of adduct formation of the nickel(II) and copper(II) Schiff base complexes with a

Zahra Asadi; Mozaffar Asadi; Fatemeh Mosalanezhad

2011-01-01

25

Antiradical activity of different copper(II) Schiff base complexes and their effect on alloxan-induced diabetes.  

PubMed

Considering the important role of antioxidants in biological systems, the group of copper(II) complexes derived from salicylaldehyde and alpha- or beta-alanine and its thiourea derivative and copper(II) complexes derived from pyruvic acid and beta-alanine were studied. The antiradical activity of the tested compounds was studied by both in vitro and in vivo methods. The chemical methods based on inhibition of INT-formazane or 3-nitrotyrosine formation were used for the evaluation of SOD-mimic and antiperoxynitrite activity, respectively. In the case of in vivo activity evaluation, an alloxan-induced diabetes mellitus model in mice was used, the mechanism of action of alloxan being closely connected with the formation of free radicals selectively damaging the pancreatic beta-cells. Since all the substances studied showed different positive effects, it is obvious that they have not acted only as a source of copper(II) ions but their effect is related to their specific chelate structure. The obtained results are a contribution to the knowledge of copper(II) Schiff base complexes with ligands of aldimine or ketimine type and form the basis for further preclinical tests of these bioactive agents in biological models of oxidative stress. PMID:15646262

Vanco, Ján; Svajlenová, Ol'ga; Ramanská, Eva; Muselík, Jan; Valentová, Jindra

2004-01-01

26

Syntheses and characterizations of zinc(II) and copper(II) complexes with reduced Schiff base derived from salicylaldehyde and D,L-selenomethionine  

Microsoft Academic Search

New zinc(II) and copper(II) complexes with a reduced Schiff-base ligand derived from D,L-selenomethionine and salicylaldehyde have been synthesized and characterized by elemental analysis, magnetic susceptibility, IR, and NMR measurements. The single-crystal X-ray structure of the Cu(II) complex reveals that this complex is a carboxylate-bridged dimer of dinuclear copper(II) subunits and all metal centers are five-coordinate with O4N donor sets in

Ling-Yun Wang; Xue-Guang Ran; De-Rong Cao; Jie Hao

2011-01-01

27

Oxindole-Schiff base copper(II) complexes interactions with human serum albumin: spectroscopic, oxidative damage, and computational studies.  

PubMed

CD and EPR were used to characterize interactions of oxindole-Schiff base copper(II) complexes with human serum albumin (HSA). These imine ligands form very stable complexes with copper, and can efficiently compete for this metal ion towards the specific N-terminal binding site of the protein, consisting of the amino acid sequence Asp-Ala-His. Relative stability constants for the corresponding complexes were estimated from CD data, using the protein as competitive ligand, with values of log K(CuL) in the range 15.7-18.1, very close to that of [Cu(HSA)] itself, with log K(CuHSA) 16.2. Some of the complexes are also able to interfere in the alpha-helix structure of the protein, while others seem not to affect it. EPR spectra corroborate those results, indicating at least two different metal species in solution, depending on the imine ligand. Oxidative damage to the protein after incubation with these copper(II) complexes, particularly in the presence of hydrogen peroxide, was monitored by carbonyl groups formation, and was observed to be more severe when conformational features of the protein were modified. Complementary EPR spin-trapping data indicated significant formation of hydroxyl and carbon centered radicals, consistent with an oxidative mechanism. Theoretical calculations at density functional theory (DFT) level were employed to evaluate Cu(II)-L binding energies, L-->Cu(II) donation, and Cu(II)-->L back-donation, by considering the Schiff bases and the N-terminal site of HSA as ligands. These results complement previous studies on cytotoxicity, nuclease and pro-apoptotic properties of this kind of copper(II) complexes, providing additional information about their possibilities of transport and disposition in blood plasma. PMID:19595461

da Silveira, Vivian Chagas; Caramori, Giovanni Finoto; Abbott, Mariana Pedrinha; Gonçalves, Marcos Brown; Petrilli, Helena Maria; da Costa Ferreira, Ana Maria

2009-10-01

28

Copper(II) complexes with multidentate Schiff-base ligands containing imidazole groups: ligand-complex or self-complementary molecule?  

Microsoft Academic Search

The copper(II) complexes with multidentate Schiff-base ligands containing imidazole groups have potentially donor and acceptor character in the formation of a coordination bond and a hydrogen bond. They can function as a ligand-complex or as a self-complementary building block for the construction of the assembly structure due to the formation of a coordination bond or a hydrogen bond. In such

Yukinari Sunatsuki; Yuri Motoda; Naohide Matsumoto

2002-01-01

29

Synthesis, crystal structure and DNA-binding properties of a new copper(II) complex with l-valine Schiff base and 1,10-phenanthroline  

Microsoft Academic Search

A new copper(II) complex, [Cu(sal-l-val)phen] (sal-l-val=a Schiff base derived from salicylaldehyde and l-valine, phen=1,10-phenanthroline), has been synthesized and characterized by elemental analysis, IR spectra and X-ray single crystal diffraction. Results show that this crystal structure of the copper(II) complex belongs to triclinic crystal system, P1 space group with crystallographic data: a=10.3710(16)Å, b=13.9350(19)Å, c=16.670(2)Å, ?=79.970(2)°, ?=75.623(2)°, ?=84.160(3)° and Z=4. The copper(II)

Jianfang Dong; Lianzhi Li; Guihua Liu; Tao Xu; Daqi Wang

2011-01-01

30

Copper(II) complexes of sterically hindered Schiff base ligands: Synthesis, structure, spectra and electrochemistry  

Microsoft Academic Search

The synthesis, structure and spectral and redox behaviour of copper(II) complexes of sterically constrained N3, N3S2 and N2S2 ligands are described. The ligands 2,6-bis(2,4,6-trimethylphenyliminomethyl)pyridine (L1), 2,6-bis(2,6-diisopropylphenyliminomethyl)pyridine (L2), 2,6-bis(2-methylthiophenyliminomethyl)pyridine (L3), 1,3-bis(2-methylthiophenyliminomethyl)benzene (L4), 1,3-bis(2,4,6-trimethylphenyliminomethyl)benzene (L5) and 1,3-bis(2,6-diisopropyl-phenyliminomethyl)benzene (L6) have been synthesized. The 1:1 copper(II) complexes of L1–L5 have been isolated and characterized by spectral and electrochemical techniques. The X-ray crystal structure of

Ramalingam Balamurugan; Mallayan Palaniandavar; Malcolm A. Halcrow

2006-01-01

31

PENTADENTATE LIGANDS VIII. COPPER(II) COMPLEXES OF SCHIFF BASE LIGANDS  

Microsoft Academic Search

Copper(II) complexes of a related series of potentially pentadentate ligands derived from substituted salicylaldehydes and 2,2?-(aminoethyl)-sulfide, 3,3?-bis(aminopropyl)sulfide, 3,3?-bis(aminopropyl)ether and diethylenetriamine have been prepared. Elemental analysis, mass, infrared and visible spectra and magnetic susceptibility measurements have been employed in order to characterize these new compounds. The materials appear to be monomeric in the solid state exhibiting no abnormal magnetic properties at

L. T. Taylor

1973-01-01

32

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

Microsoft Academic Search

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

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

1975-01-01

33

Synthesis and characterization of copper(II) complexes of the methylpyruvate Schiff base of S-methyldithiocarbazate (Hmpsme) and the X-crystal structures of Hmpsme and [Cu(mpsme)Cl  

Microsoft Academic Search

New copper(II) complexes of general formula, [Cu(mpsme)X] (mpsme=anionic form of the methylpyruvate Schiff base of S-methyldithiocarbazate; X=Cl?, Br?) have been prepared and characterized by a variety of physico-chemical techniques. Based on magnetic and spectral evidence, a square-planar structure is assigned to these complexes. Reaction of the Schiff base with copper(II) nitrate does not yield a nitrato–copper(II) complex of the ligand.

Mohammad Akbar Ali; Aminul Huq Mirza; Ray J. Butcher

2001-01-01

34

Copper(II) complexes of symmetrical and unsymmetrical tetradentate Schiff base ligands incorporating 1-benzoylacetone: Synthesis, crystal structures and electrochemical behavior  

Microsoft Academic Search

Three new copper(II) complexes [CuL1]2(ClO4)2 (1), [CuL2]ClO4 (2) and [CuL3] (3) with three Schiff base ligands [HL1=1-phenyl-3-{3-[(pyridin-2-ylmethylene)-amino]-propylimino}-butan-1-one, HL2=1-phenyl-3-[3-(1-pyridin-2-yl-ethylideneamino)-propylimino]-butan-1-one and H2L3=3-[3-(1-methyl-3-oxo-3-phenyl-propylideneamino)-propylimino]-1-phenyl-butan-1-one] have been synthesized and structurally characterized by X-ray crystallography. The mono-negative tetradentate asymmetric Schiff base ligands (L1)? and (L2)? are chelated in complexes 1 and 2 to form square planar copper(II) complexes. In complex 1, the two units are associated

Biswarup Sarkar; Gabriele Bocelli; Andrea Cantoni; Ashutosh Ghosh

2008-01-01

35

Nickel(II) copper(II) complexes Schiff base ligands containing N4O2 N4S2 donors parole terminal binding groups: Synthesis characterization X-ray structures Daft electrochemical studies  

EPA Pesticide Factsheets

Did you mean: Nickel(II) copper(II) complexes Schiff base ligands containing N4O2 N4S2 donors parole terminal binding groups: Synthesis characterization X-ray structures Daft electrochemical studies ?

36

Photofunctional supramolecular solution systems of chiral Schiff base nickel(II), copper(II), and zinc(II) complexes and photochromic azobenzenes  

Microsoft Academic Search

Preparations, crystal structures, electronic and CD spectra are reported for new chiral Schiff base complexes, bis(N-R-1-naphthylethyl-3,5-dichlorosalicydenaminato)nickel(II), copper(II), and zinc(II). Nickel(II) and copper(II) complexes adopt a square planar trans-[MN2O2] coordination geometry with ?(R,R) configuration. While zinc(II) complex adopts a compressed tetrahedral trans-[MN2O2] one with ?(R,R) configuration and exhibits an emission band around 21000cm?1 (?ex=27000cm?1). Absorption and CD spectra were recorded in

Takashiro Akitsu

2007-01-01

37

Double-strand DNA cleavage induced by oxindole-Schiff base copper(II) complexes with potential antitumor activity.  

PubMed

Some oxindole-Schiff base copper(II) complexes have already shown potential antitumor activity towards different cells, inducing apoptosis in a process modulated by the ligand, and having nuclei and mitochondria as main targets. Here, three novel copper(II) complexes with analogous ligands were isolated and characterized by spectroscopic techniques, having their reactivity compared to the so far most active complex in this class. Cytotoxicity experiments carried out toward human neuroblastoma SH-SY5Y cells confirmed its pro-apoptosis property. DNA cleavage studies were then performed in the presence of these complexes, in order to verify the influence of ligand structural features in its nuclease activity. All of them were able to cause double-strand DNA scissions, giving rise to nicked circular Form II and linear Form III species, in the presence of hydrogen peroxide. Additionally, DNA Form II was also detected in the absence of peroxide when the most active complex, [Cu(isaepy)2]2+ 1, was used. In an effort to better elucidate their interactions with DNA, solutions of the different complexes titrated with DNA had their absorption spectra monitored. An absorbance hyperchromism observed at 260 nm pointed to the intercalation of these complexes into the DNA structure. Further, investigations of 2-deoxy-d-ribose (DR) oxidation catalyzed by each of those complexes, using 2-thiobarbituric acid reactive species (TBARS) method, and detection of reactive oxygen species (ROS) formation by spin-trapping EPR, suggested that their mechanism of action in performing efficiently DNA cleavage occurs preferentially, but not only by oxidative pathways. PMID:18295339

da Silveira, Vivian Chagas; Luz, Juliana Silva; Oliveira, Carla Columbano; Graziani, Ilaria; Ciriolo, Maria Rosa; da Costa Ferreira, Ana Maria

2008-01-01

38

Synthesis, X-ray structure and catalytic properties of a copper(II) Schiff base complex modeling the activity of the Cu B site of dopamine ?-hydroxylase  

Microsoft Academic Search

The copper(II) complex [Cu(salgly)(bpy)]·4H2O (1), where salgly is a tridentate glycinatosalicylaldimine Schiff base ligand, is prepared and structurally characterized. The complex is found to be catalytically active in the oxidation of ascorbic acid by dioxygen and the process is also effective in the presence of benzylamine giving benzaldehyde as a product, thus modeling the activity of the CuB site of

Pattubala A. N. Reddy; Riya Datta; Akhil R. Chakravarty

2000-01-01

39

Nickel(II) and copper(II) Schiff base complexes bearing benzo-15-crown-5 functionalities as probes for spectroscopic recognition of lanthanide ions  

Microsoft Academic Search

A combination of host guest and coordination chemistry in the design of a spectroscopic sensor for lanthanide and aluminium ions is described. Nickel(II) and copper(II) complexes with a N2O Schiff base ligand and bearing two benzo-15-crown-5 moieties as flexible arms have been prepared and characterised by FAB-MS, UV–Vis and FTIR spectroscopies and, depending on the transition metal, by 1H NMR

Carla Sousa; Paula Gameiro; Cristina Freire; Baltazar de Castro

2004-01-01

40

Synthesis, crystal structures, and molecular hyperpolarizabilities of a new Schiff base ligand, and its copper(II), nickel(II), and cobalt(II) metal complexes  

Microsoft Academic Search

A new ligand (HL) obtained from the Schiff base condensation of 4-(diethylamino)salicylaldehyde with 4-nitroaniline is reported, with its nickel(II), copper(II), and cobalt(II) complexes. The crystal structures are reported for the four derivatives. While, NiIIL2 and CuIIL2 are centrosymmetric molecules, CoIIL2 exhibits a pseudo-tetrahedral molecular structure. The quadratic hyperpolarizabilities (?) of HL and CoIIL2, measured by electric field induced second harmonic

Pascal G. Lacroix; Frédéric Averseng; Isabelle Malfant; Keitaro Nakatani

2004-01-01

41

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

Microsoft Academic Search

New Schiff base derivatives (L1 and L2) 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(L1)2] and [Cu(L1)2] have been synthesized with bidentate NO donor Schiff base ligand (L1). The Ni(II) and Cu(II) atoms in each complex are four coordinated in a square planar geometry. Schiff bases (L1 and L2) and complexes

Cemal ?enol; Zeliha Hayvali; Hakan Dal; Tuncer Hökelek

2011-01-01

42

Carbonyl compound dependent hydrolysis of mono-condensed Schiff bases: A trinuclear Schiff base complex and a mononuclear mixed-ligand ternary complex of copper(II)  

Microsoft Academic Search

Two Schiff bases, HL1 and HL2 have been prepared by the condensation of N-methyl-1,3-propanediamine (mpn) with salicylaldehyde and 1-benzoylacetone (Hbn) respectively. HL1 on reaction with Cu(ClO4)2·6H2O in methanol produced a trinuclear CuII complex, [(CuL1)3(?3-OH)](ClO4)2·H2O·0.5CH2Cl2 (1) but HL2 underwent hydrolysis under similar reaction conditions to result in a ternary CuII complex, [Cu(bn)(mpn)ClO4]. Both complexes have been characterised by single-crystal X-ray analyses,

Subrata Naiya; Biswarup Sarkar; You Song; Sandra Ianelli; Michael G. B. Drew; Ashutosh Ghosh

2010-01-01

43

Copper(II) and Zinc(II) Complexes of Schiff Bases Derived from Amino Acids and O-Vanillin  

Microsoft Academic Search

Some new Cu(II) and Zn(II) complexes of Schiff bases derived from o-vanillin and glycine, DL-alanine, DL-valine, DL-methionine, L-leucine, and L-phenylalanine have been synthesized and characterized by elemental analyses, molar electrical conductivity, electronic and infrared spectra, and thermogravimetric analyses. The results suggested that the Schiff bases are bivalent anions with tridentate ONO donors derived from the carboxylate oxygen, imino nitrogen, and

Guangbin Wang; James C. Chang

1994-01-01

44

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)

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.

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

2012-08-01

45

Study on potential antitumor mechanism of a novel Schiff base copper(II) complex: synthesis, crystal structure, DNA binding, cytotoxicity and apoptosis induction activity.  

PubMed

A new cytotoxic copper(II) complex with Schiff base ligand [Cu(II)(5-Cl-pap)(OAc)(H(2)O)]·2H(2)O (1) (5-Cl-pap=N-2-pyridiylmethylidene-2-hydroxy-5-chloro-phenylamine), was synthesized and structurally characterized by X-ray diffraction. Single-crystal analysis revealed that the copper atom shows a 4+1 pyramidal coordination, a water oxygen appears in the apical position, and three of the basal positions are occupied by the NNO tridentate ligand and the fourth by an acetate oxygen. The interaction of Schiff base copper(II) complex 1 with DNA was investigated by UV-visible spectra, fluorescence spectra and agarose gel electrophoresis. The apparent binding constant (K(app)) value of 6.40×10(5) M(-1) for 1 with DNA suggests moderate intercalative binding mode. This copper(II) complex displayed efficient oxidative cleavage of supercoiled DNA, which might indicate that the underlying mechanism involve hydroxyl radical, singlet oxygen-like species, and hydrogen peroxide as reactive oxygen species. In addition, our present work showed the antitumor effect of 1 on cell cycle and apoptosis. Flow cytometric analysis revealed that HeLa cells were arrested in the S phase after treatment with 1. Fluorescence microscopic observation indicated that complex 1 can induce apoptosis of HeLa cells, whose process was mediated by intrinsic mitochondrial apoptotic pathway owing to the activation of caspase-9 and caspase-3. PMID:21463568

Qiao, Xin; Ma, Zhong-Ying; Xie, Cheng-Zhi; Xue, Fei; Zhang, Yan-Wen; Xu, Jing-Yuan; Qiang, Zhao-Yan; Lou, Jian-Shi; Chen, Gong-Jun; Yan, Shi-Ping

2011-05-01

46

Synthesis, crystal structure and magnetic properties of quasi-linear tetranuclear copper(II) Schiff base complexes formed by covalent linkage of asymmetrically dibridged dicopper(II) units  

Microsoft Academic Search

Alkoxo-phenoxo bridged tetranuclear copper(II) complexes [Cu4L2(O2CC6H4-p-OH)2] (1) and [Cu4L2(O2CC6H4-o-OH)2] (2) containing pentadentate Schiff base ligand N,N?-(2-hydroxypropane-1,3-diyl)bis(salicylaldimine) (H3L) are prepared and structurally characterized. Crystal structures of the complexes show the covalent linkage between two {Cu2L(O2CR)}(R = C6H4-p-OH, C6H4-o-OH) units through the phenoxo atoms of the Schiff base ligand showing axial\\/equatorial bonding modes. The Cu(1)–O(2)–Cu(2) alkoxo bridge angle is 131° in 1

Arindam Mukherjee; Manas K. Saha; Indranil Rudra; Suryanarayanasastry Ramasesha; Munirathinam Nethaji; Akhil R. Chakravarty

2004-01-01

47

Synthesis, crystal structure and DNA-binding properties of a new copper(II) complex with L-valine Schiff base and 1,10-phenanthroline  

NASA Astrophysics Data System (ADS)

A new copper(II) complex, [Cu(sal- L-val)phen] (sal- L-val = a Schiff base derived from salicylaldehyde and L-valine, phen = 1,10-phenanthroline), has been synthesized and characterized by elemental analysis, IR spectra and X-ray single crystal diffraction. Results show that this crystal structure of the copper(II) complex belongs to triclinic crystal system, P1 space group with crystallographic data: a = 10.3710(16) Å, b = 13.9350(19) Å, c = 16.670(2) Å, ? = 79.970(2)°, ? = 75.623(2)°, ? = 84.160(3)° and Z = 4. The copper(II) complex has four independent structures in the crystallographic asymmetric unit, three of them show distorted square-pyramidal and the fourth displays distorted trigonal bipyramid CuN 3O 2 coordination geometry. In the crystal, ?-? stacking and the intermolecular hydrogen bonds form two-dimensional network. The interactions between the copper(II) complex and calf thymus DNA(CT-DNA) have been studied by using UV, fluorescence and CD spectra, as well as viscosity and thermal denaturation measurements. Experiment results confirm that the copper(II) complex binds to CT-DNA in an intercalative mode.

Dong, Jianfang; Li, Lianzhi; Liu, Guihua; Xu, Tao; Wang, Daqi

2011-02-01

48

A novel tetra(? 3-phenoxo) bridged copper(II) Schiff base complex containing a Cu 4O 4 cubane core: Synthesis, structural aspects and magneto-structural correlations  

Microsoft Academic Search

A novel tetranuclear complex, [Cu4L4]·Na·ClO4 (1) has been prepared from an interesting multidentate Schiff base ligand H2L resulting from the 1:1 condensation of 3-methoxysalicylaldehyde with benzhydrazide. The prepared complex has been characterized by elemental analysis, FT-IR, UV–Vis spectroscopy, electrochemical studies and single crystal X-ray diffraction analysis. The Cu4O4 cubane core consists of four ?3-phenoxo-bridged copper(II) atoms giving an approximately cubic

Joy Chakraborty; Santarupa Thakurta; Guillaume Pilet; Dominique Luneau; Samiran Mitra

2009-01-01

49

Synthesis and mesomorphic properties of symmetric tetradentate Schiff bases based on azo-containing salicylaldimines and their copper(II) complexes  

Microsoft Academic Search

Two new tetradentate Schiff bases, in which two identical aromatic bent core mesogenic units containing phenylazo are connected via a 1,2-phenylene spacer, N,N?-di-(5-(4-alkoxyphenyl)azo)-salicylidene-1,2-phenylene diimine (alkoxy?=?decyloxy, dodecyloxy), and their copper(II) complexes were synthesized and studied for their mesomorphic character. The ligands were prepared by the condensation of 5-((4-alkoxyphenyl)azo)salicylaldehydes with 1,2-phenylene diamine. The ligands and their copper complexes have been characterized by

Kamellia Nejati; Zolfaghar Rezvani; Eslam Alizadeh; Razie Sammimi

2011-01-01

50

Metal-assisted light-induced DNA cleavage activity of 2-(methylthio)phenylsalicylaldimine Schiff base copper(II) complexes having planar heterocyclic bases  

Microsoft Academic Search

Ternary copper(II) complexes [CuLL?](ClO4), where HL is NSO-donor Schiff base (2-(methylthio)phenyl)salicylaldimine and L? is NN-donor phenanthroline bases like 1,10-phenanthroline (phen), dipyridoquinoxaline (dpq) and 2,9-dimethyl-1,10-phenanthroline (dmp), are prepared and structurally characterized by X-ray crystallography. The complexes have a distorted square-pyramidal (4+1) CuN3OS coordination geometry. While [CuL(phen)](ClO4) and [CuL(dpq)](ClO4) show axial sulfur ligation, [CuL(dmp)](ClO4) has the sulfur bonded at the equatorial site.

Pattubala A. N Reddy; Bidyut K Santra; Munirathinam Nethaji; Akhil R Chakravarty

2004-01-01

51

Synthesis, crystal structure and photo-induced DNA cleavage activity of ternary copper(II) complexes of NSO-donor Schiff bases and NN-donor heterocyclic ligands  

Microsoft Academic Search

New ternary copper(II) complexes [CuLnB](ClO4) (1–3), where HLn is the NSO donor Schiff base derived from the condensation of 2-mercaptoethylamine hydrochloride with salicylaldehyde (HL1) or 2-hydroxy-3-methoxybenzaldehyde (HL2) and B is NN-donor heterocyclic base like 2,2?-bipyridine (bpy, 1), 1,10-phenanthroline (phen, 2) or 2,9-dimethyl-1,10-phenanthroline (dmp, 3), are prepared, structurally characterized by X-ray crystallography and their DNA cleavage activity studied. The complexes show

Shanta Dhar; Munirathinam Nethaji; Akhil R. Chakravarty

2005-01-01

52

Antiradical activity of different copper(II) Schiff base complexes and their effect on alloxan-induced diabetes  

Microsoft Academic Search

Considering the important role of antioxidants in biological systems, the group of copper(II) complexes derived from salicylaldehyde and ?- or ?-alanine and its thiourea derivative and copper(II) complexes derived from pyruvic acid and ?-alanine were studied. The antiradical activity of the tested compounds was studied by both in vitro and in vivo methods. The chemical methods based on inhibition of

Ján Van?o; O?ga Švajlenová; Eva Ra?anská; Jan Muselík; Jindra Valentová

2004-01-01

53

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

PubMed Central

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

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

2006-01-01

54

Synthesis, crystal structures and magnetic properties of new oxalato- and phenolato-bridged binuclear copper(II) complexes with Schiff-base ligands  

Microsoft Academic Search

Two binuclear complexes of copper(II), [(Hfsaaep)Cu(?-C2O4)Cu(Hfsaaep)] (1) and [Cu2(Hfsadmpn)2(H2O)2](ClO4)2 (2), have been synthesized by using Schiff-base ligands derived from 3-formyl-salicylic acid: 3-[N-2-(pyridylethyl)formimidoyl]salicylic acid (H2fsaaep) and 3-N-[N?,N?-dimethylaminopropyl)formimidoyl]salicylic acid (H2fsadmpn). The crystal structures of compounds 1 and 2 have been solved. That of compound 1 consists of neutral binuclear entities with copper atoms bridged by one oxalato group, which connect axial–equatorial positions

Floriana Tuna; Gabriel Ionut Pascu; Jean-Pascal Sutter; Marius Andruh; Stéphane Golhen; Joseph Guillevic; Hans Pritzkow

2003-01-01

55

Study on potential antitumor mechanism of a novel Schiff Base copper(II) complex: Synthesis, crystal structure, DNA binding, cytotoxicity and apoptosis induction activity  

Microsoft Academic Search

A new cytotoxic copper(II) complex with Schiff base ligand [CuII(5-Cl-pap)(OAc)(H2O)]·2H2O (1) (5-Cl-pap=N-2-pyridiylmethylidene-2-hydroxy-5-chloro-phenylamine), was synthesized and structurally characterized by X-ray diffraction. Single-crystal analysis revealed that the copper atom shows a 4+1 pyramidal coordination, a water oxygen appears in the apical position, and three of the basal positions are occupied by the NNO tridentate ligand and the fourth by an acetate oxygen.

Xin Qiao; Zhong-Ying Ma; Cheng-Zhi Xie; Fei Xue; Yan-Wen Zhang; Jing-Yuan Xu; Zhao-Yan Qiang; Jian-Shi Lou; Gong-Jun Chen; Shi-Ping Yan

2011-01-01

56

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

Microsoft Academic Search

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

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

2010-01-01

57

Synthesis and Characterization of Nickel (II), Cobalt (II), Copper(II), Manganese (II), Zinc (II), Zirconium (IV), Oxomolybdenum (V), and Dioxouranium (VI) Complexes of the Schiff Base Derived from Salycylaldehyde and Thiophene2Carboxylic Acid Hydrazide  

Microsoft Academic Search

Several new coordination complexes of nickel (II), cobalt (II), copper(II), manganese(II), zinc(II), zirconium (IV), oxomolybdenum (V), and dioxouranium (VI) with the new Schiff base derived from salicylaldehyde and thiophene-2-carboxylic acid hydrazide have been synthesized and characterized by elemental analysis, electrical conductance, molecular weight, oxidimetric titration, electronic and IR spectra, and magnetic susceptibility measurements. The Schiff base behaves as a dibasic,

A. Syamal; M. R. Maurya; E. Dooms; J. A. McLean Jr

1986-01-01

58

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

PubMed Central

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.

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

2014-01-01

59

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

PubMed

Novel mixed ligand bivalent copper complexes [Cu. L. A. ClO 4 ] 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)/2,2(1)-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

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

2014-01-01

60

Copper(II) and ruthenium(II)\\/(III) Schiff base complexes  

Microsoft Academic Search

Metal complexes of general formula [Cu(L)](ClO4)2, [Ru(L)(PPh3)2]Cl2 and [Ru(L)(PPh3)Cl]Cl2[L = 1,4-di- (o-benzylidiminophenoxy\\/benzylidiminophenylthio)butane] containing N2O2 or N2S2 donor atoms have been prepared and characterised by spectral, magnetic and cyclic voltammetric studies. The rhombic nature of the e.s.r. spectra of the RuIII complexes indicates an asymmetry in the electronic environment around the Ru atom. e.s.r. spectra of the CuII complexes show a

Gurusamy Rajagopal; Nagarajan Prasanna; Periakaruppan Athappan

1999-01-01

61

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

PubMed

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. PMID:24699287

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

2014-07-15

62

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)

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.

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

2014-07-01

63

Thermal decomposition kinetics of Schiff base complexes of copper(II) and palladium(II)  

Microsoft Academic Search

Thermogravimetric (TG), derivative thermogravimetric (DTG) and differential thermal analysis (DTA) curves of CuL2 and Pd(LH)2Cl2 (LH=salicylidene-2-aminofluorene and 2-hydroxy-1-naphthalidene-2-aminofluorene) in air are studied. Mass loss considerations at the main decomposition stages indicate conversion of the complex to oxides. Mathematical analysis of TG data shows that first order kinetics are applicable in all cases. Kinetic parameters (energy and entropy of activation and

V. Indira; G. Parameswaran

1987-01-01

64

Synthesis and Crystal Structures of Ternary Copper(II) Complex Containing Salicylaldehyde Schiff Base and 4,4?Bipyridine  

Microsoft Academic Search

\\u000a Abstract  A new ternary mixed-ligand complex [Cu2(sal-glu)2(bipy)(H2O)2] · (H2O) (bipy = 4,4?-bipyridine and sal-glu = salicylaldehyde l-glutamic Schiff base) has been synthesized and characterized by X-ray diffraction. It crystallizes in the triclinic system,\\u000a space group P-1 with a = 9.6199(13) Å, b = 9.9111(13) Å, c = 9.9167(13) Å. The amino acid Schiff base coordinates to the Cu(II) ion in a tridentate mode including phenol-hydroxyl oxygen,\\u000a carboxyl oxygen and amide nitrogen atom, while the bipy coordinates

Xun Feng; Cheng-Zhi Xie; Li-Ya Wang; Yu-Fang Wang; Lu-Fang Ma

2008-01-01

65

Synthesis, crystal structure, and fluorescence properties of a two-dimensional copper(II) complex with Schiff base  

Microsoft Academic Search

A new Schiff base ligand C19H13NO5(H2L) was synthesized using 2-aminoterephthalic acid and 2-hydroxy-1-naphthaldehyde. A complex of this ligand [Cu(C19H11NO5)(C2H6O)]\\u000a n\\u000a was synthesized and characterized by IR, UV, fluorescence spectroscopy and X-ray diffraction single-crystal analysis. The\\u000a crystal crystallizes in the monoclinic system, space group Pbca with a = 8.7745(18), b = 18.613(4), c = 24.644(5) Å, V = 4024.9(14) Å3, Z

Y. H. Fan; Y. F. Wang; C. F. Bi; Q. Wang; X. Zhang; X. Y. Liu

2010-01-01

66

Synthesis, characterization, and electrochemical study of two new macroacyclic Schiff bases and their copper(II) and zinc(II) complexes  

Microsoft Academic Search

Two new potentially octadentate N2O6 Schiff-base ligands 2-((E)-(2-(2-(2-((E)-2-hydroxy-3-methoxybenzylideneamino)phenoxy)phenoxy)phenylimino)methyl)-6-methoxyphenol H2L and 2-((E)-(2-(2-(2-((E)-2-hydroxy-3-methoxybenzylideneamino)phenoxy)-4-tert-butylphenoxy)phenylimino)methyl)-6-methoxyphenol H2L were prepared from the reaction of O-Vaniline with 1,2-bis(2?-aminophenoxy)benzene or 1,2-bis(2?-aminophenoxy)-4-t-butylbenzene, respectively. Reactions of H2L and H2L with copper(II) and zinc(II) salts in methanol in the presence of N(Et)3 gave neutral [CuL]?·?0.5CH2Cl2, [CuL], [ZnL]?·?0.5CH2Cl2, and [ZnL] complexes. The complexes were characterized by IR spectra, elemental analysis, magnetic susceptibility,

Hassan Keypour; Maryam Shayesteh; Davood Nematollahi; Laura Valencia; Hadi Amiri Rudbari

2010-01-01

67

Magnetic coupling in trinuclear partial cubane copper(II) complexes with a hydroxo bridging core and peripheral phenoxo bridges from NNO donor Schiff base ligands  

Microsoft Academic Search

Three new trinuclear copper(II) complexes, [(CuL1)3(?3-OH)](ClO4)2·3.75H2O (1), [(CuL2)3(?3-OH)](ClO4)2(2) and [(CuL3)3(?3-OH)](BF4)2·0.5CH3CN (3) have been synthesized from three tridentate Schiff bases HL1, HL2, and HL3 (HL1=2-[(2-amino-ethylimino)-methyl]-phenol, HL2=2-[(2-methylamino-ethylimino)-methyl]-phenol and HL3=2-[1-(2-dimethylamino-ethylimino)-ethyl]-phenol). The complexes are characterized by single-crystal X-ray diffraction analyses, IR, UV–vis and EPR spectroscopy, and variable-temperature magnetic measurements. All the compounds contain a partial cubane [Cu3O4] core consisting of the trinuclear unit [(CuL)3(?3-OH)]2+

Chaitali Biswas; Michael G. B. Drew; Albert Figuerola; Silvia Gómez-Coca; Eliseo Ruiz; Vassilis Tangoulis; Ashutosh Ghosh

2010-01-01

68

Synthesis, structural characterization, antiradical and antidiabetic activities of copper(II) and zinc(II) Schiff base complexes derived from salicylaldehyde and beta-alanine.  

PubMed

A series of copper(II) and zinc(II) complexes involving a tridentate O,N,O'-donor Schiff base derived from salicylaldehyde and beta-alanine {i.e. N-salicylidene-beta-alanine(2-), (L)}, having the composition [Cu(2)(L)(2)(H(2)O)].H(2)O (1), [Cu(L)(H(2)O)](n) (2), and [Zn(L)(H(2)O)](n) (3), have been prepared and characterized by elemental analyses, UV-visible (UV-VIS), FT-IR and ESI-MS spectra, and thermal analyses. Complexes 1 and 2 have been investigated by single crystal X-ray analysis and also by temperature dependent magnetic susceptibility measurements (294-80K). All prepared complexes have been evaluated by the antiperoxynitrite activity assay and alloxan-induced diabetes model. The significant antioxidant and antidiabetic activities have been found in the case of both copper(II) complexes 1 and 2. In spite of first two complexes, the zinc(II) complex 3, as well as the potassium salt of the ligand (KHL) showed only insignificant protective effect against the tyrosine nitration in vitro. PMID:18037491

Vanco, Ján; Marek, Jaromír; Trávnícek, Zdenek; Racanská, Eva; Muselík, Jan; Svajlenová, Ol'ga

2008-04-01

69

A novel copper(II) complex with schiff base derived from o -vanillin and L-methionine: Syntheses and crystal structures  

Microsoft Academic Search

A new Schiff base copper(II) complex, {[CuL(H2O)2][CuL(H2O)]3 · 4H2O · C3H7NO}\\u000a n\\u000a (H2L = (Z)-2-(2-hydroxy-3-methoxybenzylideneamino)-4-(methylthio)butanoic acid), was synthesized and characterized by IR, UV,\\u000a and X-ray diffraction single-crystal analysis. The crystal belongs to the triclinic crystal system, space group with cell\\u000a parameters a = 5.2027(5) Å, b = 16.6916(16) Å, c = 20.237(2) Å, ? = 88.895(10)°, ? = 84.127(1)°, ?

Q. Wang; C. F. Bi; Y. H. Fan; X. Zhang; J. Zuo; S. B. Liu

2011-01-01

70

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)

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

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

2010-09-01

71

Synthesis, characterization, catalase functions and DNA cleavage studies of new homo and heteronuclear Schiff base copper(II) complexes  

Microsoft Academic Search

A new tetradentate diimine–dioxime ligand containing a donor set of N4, and its homo-, heterodinuclear and homotrinuclear copper(II) complexes were prepared and characterized on the basis of their elemental analysis, FT-IR, 1H and 13C NMR spectra, molar conductivity and magnetic moment measurements. The extraction ability of N,N??-bis[1-biphenyl-2-hydroxyimino-1-ethylidene]-diethylenetriamine was also evaluated in chloroform by using several transition metal picrates such as

Bulent Dede; Ismail Ozmen; Fatma Karipcin

2009-01-01

72

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

PubMed

Cu(ii) complexes with Schiff bases derived from 2-pyridin-2-ylethanamine were obtained and characterized by UV-Vis, fluorescence, and IR spectra. The X-ray crystal structures determined for [Cu(ii)(epy(di-t-Buba))Cl] × 0.042H2O and [Cu(ii)(epy(di-t-Buba))O2CCH3] revealed tetrahedral distortion of the Cu(ii) coordination sphere in the solid phase. For both molecules the Cu(ii) ions were found in tetragonal environments, as was confirmed by the values of EPR g-matrix diagonal components. The thermal properties of the complexes and the gas phase composition were studied by TG/IR techniques. Thin layers of the studied copper(ii) complexes were deposited on Si(111) by a spin coating method and characterized by scanning electron microscopy (SEM/EDS), atomic force microscopy (AFM) and fluorescence spectra. For copper(ii) layers the most intensive fluorescence band from intra-ligand transition was observed between 498 and 588 nm. The layers' fluorescence intensity was related to the rotation speed and deposition time. PMID:24848427

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

2014-07-14

73

Magnetic, spectroscopic and X-ray crystallographic structural studies on copper(II) complexes of tridentate NNS Schiff base ligands formed from 2-acetylpyrazine and S-methyl- and S-benzyldithiocarbazates  

Microsoft Academic Search

New copper(II) complexes of general empirical formula, [Cu(NNS)X] (NNS=anionic forms of the 2-acetylpyrazine Schiff bases of S-methyl- and S-benzyldithiocarbazate, Hapsme and Hapsbz) and X=Cl?, Br?, NCS? and NO3? have been synthesized and characterized. X-ray crystal structures of the free ligand, Hapsbz and the complexes, [Cu(apsbz)(NO3)]?, [Cu(apsme)(NCS)]2 and [Cu(apsme)Cl]2 have been determined. In the solid state, the Schiff base, Hapsbz remains

Malai Haniti S. A. Hamid; Mohammad Akbar Ali; Aminul Huq Mirza; Paul V. Bernhardt; Boujemaa Moubaraki; Keith S. Murray

2009-01-01

74

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

Microsoft Academic Search

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

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

2005-01-01

75

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

Microsoft Academic Search

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

Mehmet Tümer; Hüseyin Köksal; Selahattin Serin

1996-01-01

76

Synthesis and Catalytic Activity of Polymer Supported Schiff Base Complexes of Copper(II) and Iron(III) Ions in Comparison to Unsupported Complexes  

Microsoft Academic Search

The polymer supported metal complexes of N,N??bis(acetyl acetone)o?phenylene?diamine (ACPDA) Schiff base were synthesized by suspension copolymerization of styrene and allyl chloride in the presence of divinyl benzene (DVB) as cross?linker and azobisisobutyronitrile (AIBN) as initiator at 70±0.1°C and then ACPDA Schiff base and metal ions were loaded on the resulting polymer beads. The cross?linked density in polymer beads was varied

K. C. Gupta; H. K. Abdulkadir

2007-01-01

77

Synthesis and characterization of cobalt(II), nickel(II), copper(II), palladium(II) and dioxouranium(VI) complexes of the antipyrine Schiff base of 3-formylsalicylic acid  

Microsoft Academic Search

A new Schiff base has been synthesized from 4-aminoantipyrine and 3-formylsalicylic acid. The ligand has a dianionic tetradentate compartmental OONO donor system. The cobalt(II), nickel(II), copper(II) and dioxouranium(VI) complexes exist in phenolato-bridged dinuclear species, while palladium(II) gives a mononuclear complex with free –COOH groups. The complexes have been characterized by elemental analyses, i.r., u.v.-vis, thermal and magnetic measurements.

Jiban Kumar Nag; Sanjib Pal; Chittaranjan Sinha

2005-01-01

78

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

PubMed

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

Gökçe, Cansu; Gup, Ramazan

2013-05-01

79

Synthesis, Spectroscopic, and Electrochemical Characterization of a Schiff Base: 4,4?-bis[(4- diethylaminosalicylaldehyde)diphenyl methane]diimine and Its Complexes With Copper(II), Cobalt(II), and Cadmium(II)  

Microsoft Academic Search

The synthesis of a new ligand tetradentate Schiff base: 4,4?-bis[(4-diethyl aminosalicylaldehyde) diphenyl methane] diimine (H2L), obtained by condensation of 4,4?-diaminodiphenyl methane with 4-diethylaminosalicylaldehyde, and its complexes with copper(II), cobalt(II) and cadmium(II), is described. The metal complexes were characterized by elemental analysis, by UV-visible, infrared, and EPR spectroscopy, by cyclic voltammetry, and by thermal analysis (DTA-TG). The coordination of the metal

Sonia Benabid; Tahar Douadi; Houria Debab; Marc De Backer; François-Xavier Sauvage

2012-01-01

80

Synthesis and Characterization of Some Cobalt(II), Copper(II), and Nickel(II) Complexes with New Schiff Bases from the Reaction of p?Aminoazobenzene with Salicylaldehyde  

Microsoft Academic Search

Two new Schiff bases have been synthesized by the reaction of p?aminoazobenzene with salicylaldehyde (LH) and the oxidative polycondensation product of LH (LH2). The complexes of cobalt(II), copper(II), and nickel(II) with LH and LH2 have been prepared. The ligands and their complexes have been characterized by elemental analyses, IR spectra, electronic absorption spectra, mass spectra, H and C NMR spectra,

Esin Peker; Selahattin Serin

2004-01-01

81

One trinuclear copper(II) complex derived from a new Schiff base ligand based on the dianion of 4-chloro-6-(hydroxymethyl)-2-((3-aminopropylimino)methyl)-phenol: Synthesis, structure, spectroscopic and magnetic properties  

Microsoft Academic Search

A linear trinuclear copper(II) complex (1), prepared from a new Schiff base ligand, namely the dianion of 4-chloro-6-(hydroxymethyl)-2-((3-aminopropylimino)methyl)-phenol, was synthesized and characterized in this paper. The X-ray structural study reveals that the geometry of the central Cu2 ion is elongated octahedral and that of the two side Cu(II) ions is distorted square pyramidal. The magnetic susceptibility measurements from 2 to

Juechao Jiang; Zhaolian Chu; Wei Huang

2009-01-01

82

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

Microsoft Academic Search

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

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

1999-01-01

83

Influence of inductive effects and steric encumbrance on the catecholase activities of copper(II) complexes of reduced Schiff base ligands.  

PubMed

A series of copper(ii) complexes derived from reduced Schiff base ligands has been synthesized and characterized by single-crystal X-ray diffraction and spectroscopic analyses. With the exception of [Cu(Ala5NO2)(H2O)] (), which crystallized as a mononuclear repeating unit, [Cu2L2(H2O)x(DMSO)y]·solvent (L = Ala5H (), Ala5OMe (), Ala5Cl (), Ala5Br (), Gly5Br (), Val5Br () and Leu5Br (), x = 1 or 2, y = 0 or 1, solvent = MeOH or DMSO and H2O) crystallized as phenoxo-bridged dinuclear building units containing Cu2O2 cores. In , , , and , the axial positions are occupied by solvent ligands and carboxylate oxygen atoms from adjacent dimers, resulting in the formation of 1D helical coordination polymers. In , a 2D network is constructed by utilizing weak CuO interactions (?2.7 Å) with carboxylate groups. All complexes have been investigated for their catecholase activities with 3,5-DTBC, and they show significant catalytic activities except for . The catalytic activities are also observed to increase with increasing +I effects, as well as increase with increasing steric bulkiness on the ?-carbon of the carboxylate group. PMID:24435550

Thio, Yude; Yang, Xiandong; Vittal, Jagadese J

2014-03-01

84

Highly polarizable metallic complexes for nonlinear optics copper(II) and nickel(II) complexes of bis(salicylaldiminato) Schiff base  

Microsoft Academic Search

In this study highly polarizable metallic complexes of Cu2+, Ni2+, and Cr3+ of Bis(salicylaldiminato) Schiff base have been synthesized. These nonlinear optical materials showed second harmonic generation (SHG) when they were pumped 1.06 micrometers Nd:YAG laser. The intensity of the SH signal varied between the metal complexes, being strongest for Ni-salen complex. An extensive study for these materials has been

Abdalla M. Darwish; R. Copeland; R. Sliz; Putcha Venkateswarlu; Manmohan D. Aggarwal; A. Williams; Kamala N. Bhat; James M. Thompson; N. B. Laxmeshwar

1996-01-01

85

The preparation, characterization, crystal structure and biological activities of some copper(II) complexes of the 2-benzoylpyridine Schiff bases of S-methyl- and S-benzyldithiocarbazate  

Microsoft Academic Search

The complexes [Cu(NNS)X] (HNNS represents the 2-benzoylpyridine Schiff bases of S-methyl- or S-benzyldithiocarbazate; X?Cl, Br, NO3) have been prepared and characterized by a variety of physico-chemical techniques. Magnetic and spectral evidence support a square-planar structure for the [Cu(Bp?SR)X] (Bp?SR=the benzoylpyridine Schiff bases; R?CH3, CH2C6H5; X?Cl, Br) and [Cu(Bp?SMe)NO3] complexes and a five-coordinate distorted square-pyramidal structure for the [Cu(Bp?SBz)NO3] complex. The

M. E. Hossain; M. N. Alam; J. Begum; M. Akbar Ali; M. Nazimuddin; F. E. Smith; R. C. Hynes

1996-01-01

86

Synthesis and Characterization of Copper(II), Nickel(II) and Cobalt(II) Complexes with Azo?Linked Schiff Base Ligands  

Microsoft Academic Search

Diazo compounds were prepared by coupling of benzenediazonium chloride ions with 4?amino?5?hydroxy?2,7?naphthalenedisulfonic acid mono sodium salt under alkaline conditions, and new Schiff bases H2L and H2L were then obtained by the condensation of 4?amino?5?hydroxy?6?(2,5?dicholorophenylazo)?2,7?naphthalene disulfonic acid disodium salt and 4?amino?5?hydroxy?6?(2?nitrophenylazo)?2,7?naphthalenedisulfonic acid disodium salt with o?vanillin. New Cu(II), Ni(II) and Co(II) complexes of the Schiff base ligands were also prepared and

Mehmet Tunçel; Selahattin Serin

2005-01-01

87

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

PubMed

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, (1)H and (13)C 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 1.34×10(4) and 2.5×10(4) M(-1), respectively. PMID:23988527

Shebl, Magdy

2014-01-01

88

Synthesis and characterisation of nickel(II), cobalt(II), manganese(II), copper(II), zinc(II), dioxouranium(VI) and dioxomolybdenum(VI) complexes of tridentate dibasic ONO donor Schiff bases derived from 2-benzothiazolecarbohydrazide and salicylaldehyde\\/2-hydroxy-1-naphthaldehyde  

Microsoft Academic Search

The syntheses of several new coordination complexes of nickel(II), cobalt(II), manganese(II), copper(II), zinc(II), dioxouranium(VI) and dioxomolybdenum(VI) with new Schiff bases derived from 2-benzothiazolecarbohydrazide and salicylaldehyde or 2-hydroxy-1-naphthaldehyde are described. These complexes have been characterised by elemental analyses, electrical conductance, magnetic susceptibility, molecular weight, i.r. and electronic spectra. The Schiff bases behave as dibasic and tridentate ligands coordinating through the ONO

Arun Syamal; Mannar Ram Maurya

1986-01-01

89

Synthesis, Magnetic and Spectral Studies of Some Mixed-Ligand Complexes of Copper(II) and Cobalt(II) with Schiff Bases and 2- or 3-Pyrazoline-5-one Derivatives  

Microsoft Academic Search

Novel hexa-coordinated mixed-ligand complexes of copper(II) and cobalt(II) of the general compositions [M(SB) (L-L) (H2O)] and [M(SB) (L)2(H2O)], where L-L = DMMASPHP and SBH2 = hbzaaH2 or hbzatH2 for M = Cu(II) or Co(II), and L = MPHP and SBH2 = hbzaaH2 or hbzatH2 for M = Cu(II) or Co(II), have been synthesised by refluxing the respective metal salt\\/Schiff base\\/pyrazoline

R. C. Maurya; D. D. Mishra; R. Rathore; S. Jain

1994-01-01

90

Synthesis and Characterization of Copper(II), Zinc(II), Nickel(II) and Cobalt(II) Complexes with a New Schiff Base Containing Glycyl-DL-Phenylalanine  

Microsoft Academic Search

A new Schiff base. H2[DB:G-P]. obtained from 2,4-dihydroxybenzaldehyde and glycyl-DL-phenylalanine reacted with Cu(II), Zn(II). Ni(II) and Co(II) to yield new complexes. The complexes were characterized hy elemental analyses. molar conductance, H NMR, DTA, TG, IR and UV spectroscopy. In these complexes the ligand is coordinated to the metal through its phenolic oxygen, carboxyl oxygen, imino nitrogen and amide nitrogen. All

Wang Guangbin; Miao Zhiwei; Liu Xiaolan; Miao Fangming

1998-01-01

91

Zeolite-encapsulated copper (II) complexes with N 3O 2 Schiff bases: synthesis and characterization  

Microsoft Academic Search

Copper(II) complexes with N3O2 Schiff base ligands[B: bis-(acetylacetone)-3-amino-bis(propylenediimine) = H2(acac)2trien; C: bis-(acetylacetone)-3-methylamino-bis(propylenediimine) = H2(acac)2Metrien] were encapsulated in the supercages of zeolite Y in a two-step process: (i) adsorption of copper(II) acetylacetonate in the supercage of the zeolite; (ii) in-situ Schiff base condensation of the copper(II) acetylacetonate complex with corresponding triamine. The resulting materials were purified by Soxhlet extraction. Bulk and

I. Neves; C. Freire; A. N. Zakhárov; B. de Castro; J. L. Figueiredo

1996-01-01

92

Synthesis and characterization of copper(II) complexes with dissymmetric tetradentate Schiff base ligands derived from aminothioether pyridine. Crystal structures of [Cu(pytIsal)]ClO 4·0.5CH 3OH and [Cu(pytAzosal)]ClO 4  

Microsoft Academic Search

The copper(II) complexes of dissymmetric tetradentate Schiff base ligands containing a mixed donor set of NSNO ([Cu(pytXsal)]ClO4) were prepared and characterized by analytical methods and their electrochemical behaviors were studied. The crystal structures of two complexes were determined. The copper atom in both complexes lies in a slightly tetrahedrally distorted square planar coordination.

Nezameddin Daneshvar; Ali A. Entezami; Ali A. Khandar; L. A. Saghatforoush

2003-01-01

93

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

Microsoft Academic Search

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

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

2011-01-01

94

Copper(II), cobalt(II), nickel(II) and zinc(II) complexes of Schiff base derived from benzil-2,4-dinitrophenylhydrazone with aniline  

Microsoft Academic Search

New Schiff base chelates of Cu(II), Co(II), Ni(II) and Zn(II) derived from benzil-2,4-dinitro-phenylhydrazone with aniline\\u000a have been synthesised. Microanalytical data, molar conductance, and magnetic susceptibility values have been obtained, and\\u000a IR,1H NMR,13C NMR, UV-Vis, CV and EPR spectral studies have been carried out to suggest tentative structures for the complexes

N. Raman; S. Ravichandran; C. Thangaraja

2004-01-01

95

Synthesis, characterization and electrochemical behaviour of some copper(II) complexes with linear and tripodal tetradentate ligands derived from Schiff bases  

Microsoft Academic Search

New copper(II) complexes [Cu(H2L)(H2O)n]Cl2·xH2O (n = 0 or 2) with linear and tripodal tetradentate ligands have been synthesized and characterized using elemental analysis, molar conductance, IR spectra, magnetic measurements, electronic and ESR spectra. The spectral studies support the binding of linear ligands with two N and two O donor sites to copper(II) ion, providing a square planar geometry and show

S. Djebbar-Sid; O. Benali-Baitich; J. P. Deloume

1997-01-01

96

Synthesis and characterization of new azo-linked Schiff bases and their cobalt(II), copper(II) and nickel(II) complexes  

Microsoft Academic Search

Azo compounds were prepared by the reaction between benzenediazonium chloride and 4-amino-5-hydroxy-2,7-naphthalenedisulfonic\\u000a acid monosodium salt under alkaline conditions. Two new azo-linked Schiff base ligands, 4-(3-methoxysalicylidene)-5-hydroxy-6-(2-hydroxyphenylazo)-2,7-naphthalene\\u000a disulfonic acid disodium salt (H2L) and 4-(3-methoxysalicylidene)-5-hydroxy-6-(2-hydroxy-4-cholorophenylazo)-2,7-naphthalenedisulfonic acid disodium salt (H2L1), have been synthesized. Also, the new CuII, NiII and CoII complexes of the azo-linked Schiff base ligands were prepared and characterized by infrared spectra,

Mehmet Tunçel; Selahattin Serin

2006-01-01

97

Synthesis and characterization of copper(II) and cobalt(II) complexes with two new potentially hexadentate Schiff base ligands. X-ray crystal structure determination of one copper(II) complex  

Microsoft Academic Search

Two new potentially hexadentate N2O4 Schiff base ligands 2-((z)-(2-(2-(2-((z)-3,5-di-tert-butyl-2-hydroxybenzylideneamino) phenoxy) phenoxy) phenylimino) methyl)-4,6-di-tert-butylphenol [H2L1] and 2-((z)-(2-(2-(2-((z)-3,5-di-tert-butyl-2-hydroxybenzylideneamino) phenoxy)-5-tert-butylphenoxy) phenylimino) methyl)-4,6-di-tert-butylphenol [H2L2] were prepared from the reaction of 3,5-di-tert-butyl-2-hydroxy benzaldehyde with 1,2-bis(2?-aminophenoxy)benzene or 1,2-bis(2?-aminophenoxy)-4-t-butylbenzene, respectively. From the direct reaction of ligands [H2L1] and [H2L2] with copper(II) and cobalt(II) salts in methanolic solution and in the presence of N(Et)3 the neutral [CuL1], [CuL2],

Hassan Keypour; Maryam Shayesteh; Abdolhossein Sharifi-Rad; Sadegh Salehzadeh; Hamidreza Khavasi; Laura Valencia

2008-01-01

98

Ferromagnetic exchange coupling in a new bis(?-chloro)-bridged copper(II) Schiff base complex: Synthesis, structure, magnetic properties and catalytic oxidation of cycloalkanes  

Microsoft Academic Search

A new (?-chloro)-bridged complex [Cu(HL)Cl]2·H2O (1) with the Schiff base ligand H2L, [2-((E)-(2-hydroxyethylimino)methyl)-4-bromophenol], has been synthesized and characterized by elemental analysis, IR, UV–Vis and EPR spectroscopic studies. X-ray diffraction studies show that 1 is a binuclear CuII complex with a pair of chlorine atoms bridging the copper atoms in a central Cu2Cl2 core. Each copper atom in 1 adopts a

Santarupa Thakurta; Partha Roy; Georgina Rosair; Carlos J. Gómez-García; Eugenio Garribba; Samiran Mitra

2009-01-01

99

Electrochemical synthesis and crystal structure of iron(II), cobalt(II), nickel(II) and copper(II) complexes of dianionic tetradentate N4 Schiff base ligand  

Microsoft Academic Search

The electrochemical oxidation of anodic metal (iron, cobalt, nickel and copper) in an acetonitrile solution of the potentially chelating Schiff base N,N(dithiodiethylenebis-(aminylydenemethylydene)-bis(1,2-phenylene)ditosylamide (H2L) afforded stable complexes of empirical formula [ML]. The compounds obtained have been characterized by microanalysis, IR spectroscopy and ES-MS mass spectrometry. The crystal and molecular structures of [FeL]·CH3CN (1) [CoL]·CH3CN (2), [NiL]·CH3CN (3) and [CuL]·CH3CN (4) have

Laura Rodríguez; Elena Labisbal; Antonio Sousa-Pedrares; José Arturo García-Vázquez; Jaime Romero; Antonio Sousa

2010-01-01

100

Preparation and characterization of a copper(II) compound with a new glycine Schiff base containing an ester function  

Microsoft Academic Search

Summary A new Schiff base was obtained from glycine and ethyl-a-ketocyclopentylcarboxylate. This forms a potassium salt K(Rgly)·H2O, where Rgly=C10H14O4N. From this salt a new copper(II) complex was prepared, Cu(Rgly')·2H2O, where Rgly'=C10H13O4N (deprotonated Schiff base). The compounds were characterized by i.r. spectroscopy, differential thermal analysis (d.t.a.) and thermogravimetric analysis (t.g.). The activation energy corresponding to the dehydration process for compounds was

Miguel A. Bafiares; Amador Angoso; Juan L. Manzano; Emilio Rodriguez; Práxedes Dévora

1989-01-01

101

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

Microsoft Academic Search

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

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

2000-01-01

102

Immobilization of copper Schiff base complexes in zeolite matrix: Preparation, characterization and catalytic study  

Microsoft Academic Search

New zeolite-immobilized hybrid catalysts Cu(NO2-salen)–NaY have been prepared by encapsulating copper(II) Schiff base complexes [where NO2-salenH2 is N,N?-(ethylene)-bis-(5-nitro-salicylaldiimine)] in NaY zeolite matrix. The hybrid materials have been characterized by UV–vis, IR and EPR spectrometry and by X-ray powder diffraction analysis. The neat copper(II) Schiff base complex [Cu(NO2-salen)(EtOH)] (1) has also been synthesized and characterized. A brilliant color change (green–gray) has

Buddhadeb Dutta; Sreyashi Jana; Rajesh Bera; Pratap Kumar Saha; Subratanath Koner

2007-01-01

103

Polymer complexes XXXVII novel models and structural of symmetrical poly-Schiff base on heterobinuclear complexes of dioxouranium(VI)  

Microsoft Academic Search

Some binary and ternary novel complexes of dioxouranium(VI) with 5-vinylsalicylaldehyde (VSH) have been prepared and characterized by various physico-chemical techniques. The amine exchange reactions of coordinated poly-Schiff bases in these complexes have been also carried out which give symmetrical tetradentate poly-Schiff base complexes. Metal exchange reaction of these dioxouranium(VI) complexes with copper(II) gives the corresponding Cu(II) complexes. Reaction of tetradentate

A. Z El-Sonbati; A. A El-Bindary; I. G. A Rashed

2002-01-01

104

Highly salicylate-selective membrane electrode based on a new thiomacrocyclic Schiff base complex of binuclear copper(II) as neutral carrier  

Microsoft Academic Search

New binuclear metallic complexes of thiomacrocyclic Schiff base, 3,9,13,19 -tetraphenyl-6,16-dithione-1,11-dithio-4,5,7,8,14,15,17,18-octaazacycloeicosa-3,8,13,18-tetraene binuclear metal(II) [M(II)2-TDDOCT] (M=Cu, Co, Ni), were synthesized and their anion response characteristics were investigated. The performances of the electrodes are considerably influenced by the nature of the central metals. The Cu(II) complex-based electrode exhibited a good selectivity to salicylate anion with an anti-Hofmeister selectivity pattern: Sal?>ClO4?>SCN?>I?>Benzoate>Br?>Acetate>F?>SO32?>NO2?>Cl?>NO3?>SO42?>H2PO4?. The electrode had

En-Ping Luo; Ya-Qing Chai; Ruo Yuan; Jian-Yuan Dai; Lan Xu

2009-01-01

105

Synthesis and Characterization of Two New Schiff Base Ligands and their Complexes with Cobalt(II), Nickel(II) and Copper(II)  

Microsoft Academic Search

Two Schiff base ligands, 2-{E-[(5-phenyl-6H-1,3,4-thiadiazin-2yl)imino]methyne}-1-naphthol (L1H) and 5-nitro-2-{[(5-phenyl-6H-1,3,4-thiadiazin-2-yl)imino]methyne}phenol (L2H) have been prepared from 5-phenyl-6H-1,3,4-thiadiazin-2-amine (A), 2-hydroxynaphthaldehyde (1) and 2-hydroxy-5-nitrobenzaldehyde (2) Mononuclear Co(II), NiII and CuII complexes of the ligands have been prepared by using CoII, NiII and CuII salts with a 1:2 metal:ligand ratio. It was determined that the bidentate behavior of the ligands is accomplished via the phenolic oxygen

Ay?egül Yazic?; Filiz Akgün

2006-01-01

106

New Complexes of Copper(II) with a Schiff Base Derived from 2-Phenyl-L, 2, 3-triazole-4-carboxaldehyde and Aniline  

Microsoft Academic Search

Copper(II) complexes of 2-phenyl-1, 2, 3-triazole-4-carboxalideneaniline (PTCA) have been synthesised and characterised using elemental analysis, conductance and magnetic measurements, IR, electronic and E. S. R. spectral studies, cyclic voltammetry and thermal analyses. The complexes have the general empirical formula [Cu(PTCA)2X2] (when X=Cl, Br or acetate group.) or [Cu(PTCA)2X]X (when X=ClO4). A distorted octahedral structure has been assigned for the complexes.

K. K. Mohammed Yusuff; C. Krishnakumar

1993-01-01

107

Syntheses of new schiff bases derived from 2-hydrazinoethanol and salicylaldehyde, substituted salicylaldehydes and their copper(I), copper(II) and oxovanadium(IV) complexes  

Microsoft Academic Search

Several new complexes ML (where M=CuII or VIV and LH2=X-C6H4(OH) CH=N-NH(CH2)2OH where X=H, 5-chloro, 5-bromo, 5-nitro, 3-ethoxy or 5,6-benzo) have been synthesized and characterized on the basis of elemental analysis, electronic and infrared spectra and magnetic susceptibility measurements. At pH ~ 5 copper(II) is reduced to copper(I) and a diamagnetic complex, CuLH · H2O is formed. At higher pH (~8)

Arun Syamal; Syeed Ahmed; Om Prakash Singhal

1983-01-01

108

Synthesis, structure and properties of ternary copper(II) complexes of ONO donor Schiff base, imidazole, 2,2?-bipyridine and 1,10-phenanthroline  

Microsoft Academic Search

Reaction of copper(II) salt with salicylidene anthanilic acid (SAA), a tridentate ligand and imidazole (ImH), a monodentate ligand or bidentate polypyridyl ligands like 2,2?-bipyridine (bipy) or 1,10-phenanthroline(phen) in MeOH:MeCN (1:1V\\/V) yields [Cu(SAA)(ImH)] (1), [Cu(SAA)(bipy)]CH3CN (2) and [Cu(SAA)(phen)] (3) in ?80% yield. These complexes were characterized by elemental analysis, magnetic susceptibility, X-band e.p.r., electronic spectroscopy and cyclic voltammetry. All the reported

R. N. Patel; Nripendra Singh; V. L. N. Gundla

2006-01-01

109

Design, synthesis, and characterization of a series of biologically active copper(II) Schiff-base coordination compounds  

Microsoft Academic Search

Four Schiff-base copper(II) complexes, [Cu(L)(Phen)(H2O)](NO3)2 (1), [Cu(L)(bipy)(H2O)](ClO4)(H2O)(NO3) (2), [Cu(L)(Dien)](ClO4)2(H2O) (3), and [Cu(L)(ImH)(H2O)](ClO4) (4) (L ?=?N-[(1)-pyridin-2-ylmethylidene]benzohydrazide, Phen?=?1,10-phenanthroline, bipy?=?2,2?-bipyridine, Dien?=?diethylenetriamine, ImH?=?imidazole), have been synthesized and characterized using various physico-chemical techniques. L is coordinated to copper(II) neutral and uninegatively charged tridentate chelating agent via the azomethine nitrogen, pyridine nitrogen, and carbonyl oxygen. The copper(II) complexes are paramagnetic with octahedral stereochemistry. The crystal structures

Ram N. Patel; Anurag Singh; Krishna K. Shukla; Vishnu P. Sondhiya; Dinesh K. Patel; Yogendra Singh; Rajesh Pandey

2012-01-01

110

Synthesis and characterization of thermally stable Schiff base polymers and their copper(II), cobalt(II) and nickel(II) complexes  

Microsoft Academic Search

In this study, the Schiff base monomers [(M1; N,N?-p-phenylenebis(salicylideneimine)) and ethylenediamine (M2; N,N?-p-ethylenebis(salicylideneimine))] were synthesized by the condensation reaction between p-phenylenediamine and aromatic aldehydes. The Schiff base polymers (SBPs) having double azomethine groups were prepared by oxidative polycondensation (OP) reaction of monomers in aqueous alkaline medium with NaOCl [P1; poly-(N,N?-p-phenylenebis(salicylideneimine)) and P2; poly-(N,N?-p-ethylenebis(salicylideneimine))] as the oxidant at 90°C. Average molecular

M. Tunçel; A. Özbülbül

2008-01-01

111

Synthesis, crystal structures, and urease inhibition studies of two new Schiff-base copper complexes derived from n-butylamine  

Microsoft Academic Search

Two Schiff-base copper(II) complexes, bis(N-n-butyl-5-chlorosalicylaldiminato) copper(II) (1) and bis(N-n-butyl-4-methoxysalicylaldiminato) copper(II) (2), were synthesized and their solid-state structures were determined by X-ray crystallography. Complex 1 displays a distorted square-planar geometry, while 2 possesses square-planar geometry. Copper(II) complexes 1 and 2 showed strong inhibitory activity against jack bean urease (IC50?=?2.7, 3.5?µmol?L), compared with acetohydroxamic acid (IC50?=?63.00?µmol?L). A molecular modeling study was carried

Yuguang Li; Zuowen Li; Yang Liu; Xiongwei Dong; Yongming Cui

2011-01-01

112

Synthesis, crystal structures, and urease inhibition studies of two new Schiff-base copper complexes derived from n-butylamine  

Microsoft Academic Search

Two Schiff-base copper(II) complexes, bis(N-n-butyl-5-chlorosalicylaldiminato) copper(II) (1) and bis(N-n-butyl-4-methoxysalicylaldiminato) copper(II) (2), were synthesized and their solid-state structures were determined by X-ray crystallography. Complex 1 displays a distorted square-planar geometry, while 2 possesses square-planar geometry. Copper(II) complexes 1 and 2 showed strong inhibitory activity against jack bean urease (IC50?=?2.7, 3.5?µmol?L), compared with acetohydroxamic acid (IC50?=?63.00?µmol?L). A molecular modeling study was carried

Yuguang Li; Zuowen Li; Yang Liu; Xiongwei Dong; Yongming Cui

2012-01-01

113

Synthesis and Biological Activity of the Schiff Base N,N?-bis(Salicylidene)thiourea and Its Complexes of Copper (II), Nickel (II) and Zinc (II)  

Microsoft Academic Search

The Schiff base N,N?-bis(salicylidene)thiourea and its complexes of copper(II), nickel(II) and zinc(II) have been synthesized and characterized by elemental analyses, molar conductivity measurements, thermal analyses, infrared and electronic spectral data. The Schiff base ligand has been further identified by H NMR and mass spectra. The results suggest that the Schiff base behaves as a quadridentate ligand attached to the metal

Zhu Xinde; Wang Chenggang; Lu Zhiping; Le Zhifeng; Wu Zishen

1996-01-01

114

Syntheses and structures of two new bis-N,O-bidentate Schiff base ligands and their respective copper(II) complexes with dinuclear double-helical configuration  

Microsoft Academic Search

Two flexible Schiff base ligands bis-[(N,N?-3,5-di-tert-butylsalicylidene)-4,4?-diaminodiphenyl] ether (H2L1) and bis-[(N,N?-3-tert-butyl-5-methylsalicylidene)-4,4?-diaminodiphenyl] ether (H2L2) were prepared in high yields and their structures were determined by X-ray single-crystal diffraction. Different packing modes were observed in H2L1 and H2L2 due to the different spacial hindrance of substituted groups bonded to the phenol rings. Reaction of ligands H2L1 and H2L2 with Cu(ClO4)2·6H2O in hot methanol

Zhaolian Chu; Wei Huang

2007-01-01

115

Dinuclear and polynuclear transition metal complexes with macrocyclic ligands. 6. New dinuclear copper(ii) complexes with macrocyclic Schiff bases derived from 4- tert -butyl-2,6-diformylphenol  

Microsoft Academic Search

New dinuclear complexes containing CuII atoms in the cavity of a macrocyclic Schiff base were prepared by template condensation of 4-tert-butyl-2,6-diformylphenol with 1,3-diaminopropane in the presence of CuII trimethylacetate and chloride as well as by extra-ligand exchange. The mononuclear CuII complex with two 1,3-diaminopropane molecules can serve as an intermediate in this template synthesis. The reaction of CuII trimethylacetate with

V. V. Roznyatovsky; N. E. Borisova; M. D. Reshetova; Yu. A. Ustynyuk; G. G. Aleksandrov; I. L. Eremenko; I. I. Moiseev

2004-01-01

116

Synthesis and Structural Characterization of Two New Schiff Bases incorporating a Piperazine Skeleton, and their Reactions with Copper(II) Perchlorate  

Microsoft Academic Search

The synthesis of Schiff bases N,N??bis(4?dodecyloxy?benzylidene?N?propyl)?piperazine (2) and N,N??bis?[4?(4??octyloxy?benzoic)?ester?benzylidene?N?propyl]?piperazine (6) in a multistep process is reported. The intermediates as well as the products were characterized by elemental analysis, melting point and IR, H and C?NMR spectroscopy. The complex formation of these Schiff bases with copper(II) perchlorate resulted in disruption of the imino bond and yielded N,N??bis(3?aminopropyl)piperazineperchloratocopper(II) perchlorate, Cu(L)(ClO4)2, where L

Liliana Cseh; Ramona Tudose; Otilia Costisor; Ingo Pantenburg; Gerd Meyer; Wolfgang Linert

2008-01-01

117

Synthesis, Characterization and Electrochemical Behaviour of Some Manganese and Copper Complexes with Tetradentate Schiff Base Ligands  

Microsoft Academic Search

A series of symmetrical tetradentate Schiff bases derived from substituted salicylaldehyde and ethylenediamine were prepared and characterized by elemental analysis, IR, UV-Visible and H NMR spectroscopy. The interaction of these bases with MnCl2 4H2O and CuCI2 2H2O have been studied, leading to the preparation of manganese(II) and copper(II) complexes. Microanalysis, molar conductance, IR, UV-Visible spectroscopy, magnetic measurements and ESR spectra

N. Tidjani-Rahmouni; S. Djebbar-Sid; N. Chenah; O. Benali-Baitich

1999-01-01

118

Synthesis and characterization of nickel(II), cobalt(II), copper(II), manganese(II), zinc(II), zirconium(IV), dioxouranium(VI) and dioxomolybdenum(VI) complexes of a new Schiff base derived from salicylaldehyde and 5-methylpyrazole-3-carbohydrazide  

Microsoft Academic Search

Summary Synthesis of a new Schiff base derived from salicylaldehyde and 5-methylpyrazole-3-carbohydrazide, and its coordination compounds with nickel(II), cobalt(II), copper(II), manganese(II), zinc(II), zirconium(IV), dioxouranium(VI) and dioxomolybdenum(VI) are described. The ligand and the complexes have been characterized on the basis of analytical, conductance, molecular weight, i.r., electronic and n.m.r. spectra and magnetic susceptibility measurements. The stoichiometries of the complexes are represented

Arun Syamal; Mannar Ram Maurya

1986-01-01

119

Dielectric properties and conductivity studies of some tetradentate cobalt(II), nickel(II), and copper(II) Schiff base complexes  

Microsoft Academic Search

Dielectric and conductivity properties of cobalt(II), nickel(II), and copper(II)–imidazole-2-carboxaldehyde-glycylglycine (imal-glygly) complexes have been studied using impedance spectroscopy. The dielectric constant and dielectric loss factor for metal complexes have been analyzed in the frequency range from 1Hz to 1MHz at room temperature. The a.c. conductivity result reveals that these complexes exhibit dissimilar frequency dependent conductivity. An attempt has been made to

R. Selwin Joseyphus; E. Viswanathan; C. Justin Dhanaraj; J. Joseph

120

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  

Microsoft Academic Search

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

Pascal G. Lacroix; Santo Di Bella; Isabelle Ledoux

1996-01-01

121

Novel copper-based therapeutic agent for anti-inflammatory: synthesis, characterization, and biochemical activities of copper(II) complexes of hydroxyflavone Schiff bases.  

PubMed

Four hydroxyflavone derivatives have been synthesized with the aim of obtaining a good model of superoxide dismutase. Better to mimic the natural metalloenzyme, copper complexes have been designed. The Cu(II) complexes of general formulae, [CuL] where L?=?5-hydroxyflavone-o-phenylenediamine (L¹H?)/m-phenylenediamine (L²H?) and 3-hydroxyflavone-o-phenylenediamine (L³H?)/m-phenylenediamine (L?H?) have been synthesized. The structural features have been determined from their analytical and spectral data. All the Cu(II) complexes exhibit square planar geometry. Redox behavior of copper complexes was studied and the present ligand systems stabilize the unusual oxidation state of the copper ion during electrolysis. The in vitro antimicrobial activities of the investigated compounds were tested against the bacterial species Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Proteus vulgaris, and Pseudomonas aeruginosa and fungal species Aspergillus niger, Rhizopus stolonifer, Aspergillus flavus, Rhizoctonia bataicola, and Candida albicans. Superoxide dismutase and anti-inflammatory activities of the copper complexes have also been measured and discussed. PMID:22238015

Joseph, J; Nagashri, K

2012-07-01

122

Synthesis, characterization and antimicrobial activity of cobalt(II), nickel(II)and copper(II) complexes with new asymmetrical Schiff base ligands derived from 7-formyanil-substituted diamine-sulphoxine and acetylacetone  

Microsoft Academic Search

Asymmetric 7-formyanil-substituted-imino-4-(4-methyl-2-butanone)-8-hydroxyquinoline-5-sulphonic acid (Schiff bases), react with CoII, NiII and CuII ions to give 1:2, 1:1 and 2:1 complexes as established by conductometric titrations in 1:1 DMF:H2O. The complexes were investigated by elemental analyses, molecular weight determinations, molar conductance, magnetic moments, thermal analysis, i.r., u.v.–vis. and e.s.r. spectra. The complexes have an octahedral crystal structure and general formula [ML·(OH2)2], where

Wageih G. Hanna; Mona M. Moawad

2001-01-01

123

Some Metal(II) Complexes of Potentially Terdentate Heterocyclic Schiff Bases  

Microsoft Academic Search

Complexes of copper(II), cobalt(II) and oxovanadium(IV) with Schiff bases obtained by condensing salicylaldehyde, substituted salicylaldehydes and 2-hydroxy-l-naphthaldehyde with 2-aminopyridine (ampy), 5-methyI-2-aminopyridine (CH3ampy) and 4-aminopyridine (4-ampy) have been synthesized and characterized. Two types of complexes [MLCI(H2O)n and ML2] were obtained, depending on whether the metal chloride or metal acetate was used for the synthesis. There is evidence that the three donor

Gabriel A. Kolawole; Adegboye O. Adeyemo

1990-01-01

124

Metal complexes of sulphur-nitrogen chelating agents. Part 14. Nickel(II), palladium(II), copper(II), cobalt(II), and cobalt(III) complexes of the tetradentate schiff bases having ONNS donor sites  

Microsoft Academic Search

Complexes of nickel(II), palladium(II), copper(II), cobalt(II), and cobalt(III) with methyl-2-(ß-salicylaldiminoethyl)-cyclopent-1-en-dithiocarboxylate (H2L1) and methyl-2-(ß-salicylaldiminoisopropyl)cyclopent-1-en-dithiocarboxylate (H2L2) have been prepared. They contain the donor sites ONNS. The metal(II) ions from neutral, monomeric square planar chelate complexes. The cobalt(III) complexes [CoL1-(H2O)2]X (X=Cl or ClO4) appear to betrans-diaqua-species. All compounds have been characterized by a number of physico-chemical methods.

Santosh K. Mondal; Parimal Paul; Rita Roy; Kamalaksha Nag

1984-01-01

125

Synthesis, crystal structure and hydrolysis of a dinuclear copper(II) complex constructed by N 2O donor Schiff base and 4,4?-bipyridine: Discrete supra-molecular ensembles vs. oligomers  

Microsoft Academic Search

The tridentate Schiff base ligand, 7-amino-4-methyl-5-aza-3-hepten-2-one (HAMAH), prepared by the mono-condensation of 1,2-diaminoethane and acetylacetone, reacts with Cu(BF4)2·6H2O to produce initially a dinuclear Cu(II) complex, [{Cu(AMAH)}2(?-4,4?-bipy)](BF4)2 (1) which undergoes hydrolysis in the reaction mixture and finally produces a linear polymeric chain compound, [Cu(acac)2(?-4,4?-bipy)]n (2). The geometry around the copper atom in compound 1 is distorted square planar while that in

Chaitali Biswas; Shouvik Chattopadhyay; Michael G. B. Drew; Ashutosh Ghosh

2007-01-01

126

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

PubMed

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. PMID:24727167

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

2014-08-14

127

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

NASA Astrophysics Data System (ADS)

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.

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

128

Study on preparation of modified lubricant containing nano-Schiff base and Schiff base copper complex in W\\/O microemulsion reactor  

Microsoft Academic Search

A successful preparation of Schiff base and Schiff base copper complex was carried out directly in polar base oil (vegetable\\u000a oil) using a water\\/oil microemulsion reactor. The prepared nanometer sized Schiff base and Schiff base copper complex dispersed\\u000a uniformly and spontaneously in the oil. The nanometer sized particles of the Cu(II) chelate of bissalicylaldehyde-ethylenediamine\\u000a and the bissalicylaldehyde-ethylenediamine in oil were

Xinlei Gao; Jian Li; Wanzhen Gao

2009-01-01

129

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

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.

Lacroix, P.G. [Universite Paris-Sud, Toulouse (France)] [Universite Paris-Sud, Toulouse (France); Di Bella, S. [Universita di Cantania (Italy)] [Universita di Cantania (Italy); Ledoux, I. [Laboratorie de Bagneux (France)] [Laboratorie de Bagneux (France)

1996-02-01

130

Designing dicyanamide bridged 1D molecular architecture from a mononuclear copper(II) Schiff base precursor: Syntheses, structural variations and magnetic study  

Microsoft Academic Search

A new tridentate N2O donor Schiff base ligand [(C6H5C(OH)CHC(CH3)NCH2C5H4N)LH] was obtained by 1:1 condensation of benzoylacetone with 2-picolylamine and has been used to synthesise a mononuclear [CuLCl] (1) and an end-to-end dicyanamide bridged polynuclear {[Cu2(?-L)2(?2-1,5-(CN)2N)]ClO4}n (2) copper(II) complexes. The ligand, 1 and 2 were clearly characterised by elemental analysis, FT-IR, 1H NMR, UV–Vis spectral studies, electrochemical studies and in addition

Aurkie Ray; Guillaume Pilet; Carlos J. Gómez-García; Samiran Mitra

2009-01-01

131

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

PubMed

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

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

2014-10-15

132

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

NASA Astrophysics Data System (ADS)

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

Das, Mithun; Chattopadhyay, Shouvik

2013-11-01

133

Oxidative peptide /and amide/ formation from Schiff base complexes  

NASA Technical Reports Server (NTRS)

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.

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

1982-01-01

134

Remarkable photocytotoxicity in hypoxic HeLa cells by a dipyridophenazine copper(II) Schiff base thiolate.  

PubMed

Copper(II) complexes [Cu(satp)(L)] (1-3) of a Schiff base thiolate (salicylidene-2-aminothiophenol, H2satp) and phenanthroline bases (L), viz. 1,10-phenanthroline (phen in 1), dipyrido[3,2-d:2',3'-f]quinoxaline (dpq in 2) and dipyrido[3,2-a:2',3'-c]phenazine (dppz in 3), were prepared, characterized and their anaerobic DNA photocleavage activity and hypoxic photocytotoxicity studied. The redox active complexes show the Cu(II)-Cu(I) couple near -0.5 V for 1 and near 0.0 V vs. SCE (saturated calomel electrode) for 2 and 3. The one-electron paramagnetic complexes (~1.85 ?B) are avid DNA binders giving Kb values within 1.0×10(5)-8.0×10(5) M(-1). Thermal melting and viscosity data along with molecular docking calculations suggest DNA groove and/or partial intercalative binding of the complexes. The complexes show anaerobic DNA cleavage activity in red light under argon via type-I pathway, while DNA photocleavage in air proceeds via hydroxyl radical pathway. The DFT (density functional theory) calculations reveal a thyil radical pathway for the anaerobic DNA photocleavage activity and suggest the possibility of generation of a transient copper(I) species due to bond breakage between the copper and sulfur to generate the thyil radical. An oxidation of the copper(I) species is likely by oxygen in an aerobic medium or by the buffer medium in an anaerobic condition. Complex 3 exhibits significant photocytotoxicity in HeLa cells (IC50=8.3(±1.0) ?M) in visible light, while showing lower dark toxicity (IC50=17.2(±1.0) ?M). A significant reduction in the dark toxicity is observed under hypoxic cellular conditions (IC50=30.0(±1.0) ?M in dark), while retaining its photocytotoxicity (IC50=8.0(±1.0) ?M). PMID:21726772

Lahiri, Debojyoti; Majumdar, Ritankar; Mallick, Dibyendu; Goswami, Tridib K; Dighe, Rajan R; Chakravarty, Akhil R

2011-08-01

135

Effect of ligand substitution on DNA binding ability of two new square planar copper(II)–Schiff base complexes  

Microsoft Academic Search

Two terdentate NNO donor Schiff base ligands CH3C(OH)CHC(CH3)NCH2C5H4N [HL1] and C6H5C(OH)CHC(CH3)NCH2C5H4N [HL2] were used to synthesize two mononuclear square planar copper(II) complexes, [CuL1(CF3COO)] (1) and [CuL2(CF3COO)] (2). The complexes were characterized by elemental analyses, FT-IR, UV–vis spectral methods and their structures were established by single crystal X-ray diffraction study. The biochemical activity of the complexes towards DNA binding were performed

Dipali Sadhukhan; Aurkie Ray; Saurabh Das; Corrado Rizzoli; Georgina M. Rosair; Samiran Mitra

2010-01-01

136

Biological and spectral studies of transition metal complexes with a quinquedentate Schiff base, 2,6-diacetylpyridine bis(thiocarbohydrazone)  

Microsoft Academic Search

Manganese(II), cobalt(II), and copper(II) complexes with a quinquedentate Schiff base, 2,6-diacetylpyridine bis(thiocarbohydrazone), have been synthesized and characterized by elemental analysis, molar conductance, magnetic susceptibility, and IR, H NMR, C NMR, mass (for ligand), UV and Electron Paramagnetic Resonance spectroscopies. The complexes are [M(L)X]X, where M=Mn(II), Co(II), and Cu(II), L = 2,6-diacetylpyridine bis(thiocarbohydrazone), and X= and Oac. The ligand with five

Sulekh Chandra; Amit Kumar Sharma

2009-01-01

137

Nickel(II) and copper(II) complexes of Schiff base ligands containing N 4O 2 and N 4S 2 donors with pyrrole terminal binding groups: Synthesis, characterization, X-ray structures, DFT and electrochemical studies  

Microsoft Academic Search

A series of hexadentate ligands, H2Lm (m=1?4), [1H-pyrrol-2-ylmethylene]{2-[2-(2-{[1H-pyrrol-2-ylmethylene]amino}phenoxy)ethoxy]phenyl}amine (H2L1), [1H-pyrrol-2-ylmethylene]{2-[4-(2-{[1H-pyrrol-2-ylmethylene]amino}phenoxy)butoxy]phenyl}amine (H2L2), [1H-pyrrol-2-ylmethylene][2-({2-[(2-{[1H-pyrrol-2-ylmethylene]amino}phenyl)thio]ethyl}thio)phenyl]amine (H2L3) and [1H-pyrrol-2-ylmethylene][2-({4-[(2-{[1H-pyrrol-2-lmethylene]amino}phenyl)thio]butyl}thio) phenyl]amine (H2L4) were prepared by condensation reaction of pyrrol-2-carboxaldehyde with {2-[2-(2-aminophenoxy)ethoxy]phenyl}amine, {2-[4-(2-aminophenoxy)butoxy]phenyl}amine, [2-({2-[(2-aminophenyl)thio]ethyl}thio)phenyl]amine and [2-({4-[(2-aminophenyl)thio]butyl}thio)phenyl]amine respectively. Reaction of these ligands with nickel(II) and copper(II) acetate gave complexes of the form MLm (m=1?4), and the synthesized ligands and their complexes have been characterized by a variety

Ali Akbar Khandar; Christine Cardin; Seyed Abolfazl Hosseini-Yazdi; John McGrady; Marjan Abedi; Seyed Amir Zarei; Yu Gan

2010-01-01

138

Solvothermal Synthesis and Crystal Structure of a 18-Membered Macrocycle Schiff Base Dinuclear Copper(II) Complex: Cu 2 (NO 3 ) 4 (APTY) 4 (APTY = 1,5-dimethyl-2-phenyl-4-{[(1 E )-pyridine-4-ylmethylene]amino}-1,2-dihydro-3 H -pyrazol-3-one)  

Microsoft Academic Search

\\u000a Abstract  A new 18-membered macrocycle Schiff base dinuclear copper(II) complex: Cu2(NO3)4(APTY)4 (1) (APTY = 1,5-dimethyl-2-phenyl-4-{[(1E)-pyridine-4-ylmethylene]amino}-1,2-dihydro-3H-pyrazol-3-one), has been successfully synthesized by solvothermal treatment of Cu(NO3)2 · 6H2O with APTY. Compound 1 crystallizes in the triclinic space group P-1 with cell parameters: a = 10.556(2) Å, b = 12.075(2) Å, c = 15.230(3) Å, ? = 74.75(3), ? = 81.50(3), ? = 70.60(3)°, V = 1762.7(6) Å3, R1 = 0.0493, wR2 = 0.1400, Z = 1, D\\u000a calc = 1.455 g\\/cm3, F(000) = 798, S = 1.009. In the compound molecules, each of the six-coordinated CuII atoms are

Hong-Yun Jin; Jing-Zhong Chen; Xian-Wen Wang; Shu-En Hou

2009-01-01

139

Synthesis, spectral studies, and antimicrobial activity of binary and ternary Cu(II), Ni(II), and Fe(III) complexes of new hexadentate Schiff bases derived from 4,6-diacetylresorcinol and amino acids  

Microsoft Academic Search

Two new hexadentate N2O4 donor Schiff bases, H4L and H4L, were synthesized by condensation of 4,6-diacetylresorcinol with glycine and alanine, respectively. The structures of the ligands were elucidated by elemental analyses, IR, H NMR, electronic, and mass spectra. Reactions of the Schiff bases with copper(II), nickel(II), and iron(III) nitrates in 1 : 2 molar ratio gave binuclear metal complexes and,

Magdy Shebl

2009-01-01

140

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

Microsoft Academic Search

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 (?) of three Schiff base ligands and

Dong-Dong Qin; Zheng-Yin Yang; Gao-Fei Qi

2009-01-01

141

Titanium(IV) complexes of disulfide-linked Schiff bases.  

PubMed

With the goal of preparing Ti(IV) complexes bearing a sulfur-based redox function of possible use in electrocatalytic oxidations of alcohols at electrode surfaces, a series of seven 2,2'-dithiodianiline Schiff-base derivatives, including two new variations, were tested in reactions with Ti(OR)(4) (R = (i)Pr, (t)Bu). Instead of the expected dimetallic products of general formula [LTi(OR)(2)](2), mononuclear species LTi(OR)(2) were obtained, confirmed by crystallographic determinations to have an unprecedented, symmetrical, and macrocyclic arrangement with four-point binding to the metal center and with the disulfide moieties remaining uncoordinated. Cyclic voltammetry performed in CH(2)Cl(2) displayed oxidations at potentials useful for fuel cells (+1.1-1.5 V vs Ag/AgCl), but despite the uncoordinated disulfide moieties, the complexes were reticent to engage in reduction processes. PMID:22515278

Donzelli, Alberto; Metushi, Imir; Potvin, Pierre G

2012-05-01

142

Synthesis of a new series of chiral Schiff's bases and their copper complexes  

Microsoft Academic Search

A new series of chiral Schiff's bases containing 2-hydroxybenzilideneaniline moieties and their copper complexes were synthesized and studied by differential scanning calorimetry, polarized optical microscopy, X-ray diffraction and EPR measurement. The results show that most of the Schiff's bases and only two of the copper complexes exhibited chiral smectic liquid crystal phases.

Yanqing Tian; Fengyu Su; Peixiang Xing; Yingying Zhao; Xinyi Tang; Xiaoguang Zhao; Enle Zhou

1996-01-01

143

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)

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.

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

2014-02-01

144

Copper(II) ion selective electrode based on a newly synthesized Schiff-base chelate  

Microsoft Academic Search

A new Cu (II) ion-selective electrode has been fabricated in poly (vinyl chloride) matrix based on a recently synthesized\\u000a Schiff-base chelate. The addition of sodium tetraphenylborate (NaTPB) and various plasticizers viz. TBP, TEHP, DOS, and CN\\u000a have been found to substantially improve the performance of the electrode. The membrane of various compositions of the ionophore\\u000a (I) were investigated and it

Ajay Kumar Jain; Raj Kumar Singh; Shalabh Jain; Jitendra Raisoni

2008-01-01

145

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

Microsoft Academic Search

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

Masoud Salavati-Niasari; Elham Zamani; Mehdi Bazarganipour

2007-01-01

146

Catalytic, Asymmetric Cyclopropanation of Diphenylethene Mediated by Chiral Copper(Schiff Base) Complexes  

Microsoft Academic Search

Asymmetric cyclopropanation of diphenylethene with diazoacetates was catalyzed by new copper-(Schiff base) complexes. The\\u000a effects of the substituents in substituted salicylaldehyde on the ee's were studied, and a 94.5% ee was achieved.

Zhengning Li; Huilin Chen

2001-01-01

147

Efficient and enantioselective nitroaldol reaction catalyzed by copper Schiff-base complexes  

Microsoft Academic Search

Mild and efficient enantioselective nitroaldol reactions of nitromethane with various aldehydes were catalyzed by chiral copper Schiff-base complexes, which can be readily prepared from amino acid, yielding the corresponding adducts with high yields and good enantiometric excess (ee).

Changsheng Gan; Guoyin Lai; Zuhui Zhang; Zhiyong Wang; Ming-Ming Zhou

2006-01-01

148

Cobalt (II), manganese (II) complexes with bidentate Schiff bases of benzhydrazide: Synthesis, characterization and electrochemical studies  

Microsoft Academic Search

The synthesis, characterization and cyclic voltammetry of some benzhydrazide Schiff bases and their metal complexes are reported. The structures of the novel complexes were elucidated by means of FTIR, FT 1H-NMR, 13C-NMR, elemental analyses, cyclic voltammetry studies and thermal gravimetric analyses. Tautomeric properties of the ligating Schiff bases were observed from the infrared and proton N MR data. The electrochemical

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

149

Complexes of a tridentate ONS Schiff base. Synthesis and biological properties  

Microsoft Academic Search

Several new complexes of a tridentate ONS Schiff base derived from the condensation of S-benzyldithiocarbazate with salicylaldehyde have been characterised by elemental analyses, molar conductivity measurements\\u000a and by i.r. and electronic spectra. The Schiff base (HONSH) behaves as a dinegatively charged ligand coordinating through\\u000a the thiolo sulphur, the azomethine nitrogen and the hydroxyl oxygen. It forms mono-ligand complexes: [M(ONS)X], [M=NiII,

M. Tofazzal H. Tarafder; Manaf A. Ali; D. Juan Wee; Kasbollah Azahari; Sidik Silong; Karen A. Crouse

2000-01-01

150

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)

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.

Tyagi, Monika; Chandra, Sulekh; Tyagi, Prateek

2014-01-01

151

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

PubMed

Complexes of manganese(II) and copper(II) of general composition M(L)2X2 have been synthesized [L=2-acetyl thiophene thiosemicarbazone and X=Cl(-) and NO3(-)]. The elemental analysis, molar conductance measurements, magnetic susceptibility measurements, mass, IR, UV, NMR and EPR spectral studies of the compounds led to the conclusion that the ligand acts as a bidentate manner. The Schiff's base ligand forms hexacoordinated complexes having octahedral geometry for Mn(II) and tetragonal geometry for Cu(II) complexes. The thermal studies suggested that the complexes are more stable as compared to ligand. In molecular modelling the geometries of Schiff's base and metal complexes were fully optimized with respect to the energy using the 6-31g(d,p) basis set. The mycological studies of the compounds were examined against the plant pathogenic fungi i.e. Rhizoctonia bataticola, Macrophomina phaseolina, Fusarium odum. PMID:23978792

Tyagi, Monika; Chandra, Sulekh; Tyagi, Prateek

2014-01-01

152

Syntheses and characterization of a chelating resin containing ONNO donor quadridentate Schiff base and its coordination complexes with copper(II), nickel(II), cobalt(II), iron(III), zinc(II), cadmium(II), molybdenum(VI) and uranium(VI) 1 ONNO indicates donor sites of the quadridentate Schiff base. 1 , 2 Presented at the National Seminar on Reactive and Functional Polymers held at Gujarat University, Ahmedabad, Gujarat, India in March, 1996. 2  

Microsoft Academic Search

A new mixed Schiff base N,N?-ethylenemono(3-carboxysalicylideneimine)mono(salicylideneimine) has been synthesized by the condensation of equimolar quantities of ethylenediamine, salicylaldehyde and 3-formylsalicylic acid. A polymer supported Schiff base (PS–CH2–LH2) has been synthesized by the reaction of chloromethylated polystyrene (containing 3.9 mmol of chlorine per g of resin and 2% cross-linked with divinylbenzene) and the Schiff base N,N?-ethylenemono(3-carboxysalicylideneimine)mono(salicylideneimine). The polymer-anchored Schiff base reacts

A. Syamal; M. M. Singh; D. Kumar

1999-01-01

153

Effect of ligand substitution on DNA binding ability of two new square planar copper(II)-Schiff base complexes  

NASA Astrophysics Data System (ADS)

Two terdentate NNO donor Schiff base ligands CH 3C(OH) dbnd CHC(CH 3) dbnd NCH 2C 5H 4N [ HL 1] and C 6H 5C(OH) dbnd CHC(CH 3) dbnd NCH 2C 5H 4N [ HL 2] were used to synthesize two mononuclear square planar copper(II) complexes, [Cu L 1(CF 3COO)] ( 1) and [Cu L 2(CF 3COO)] ( 2). The complexes were characterized by elemental analyses, FT-IR, UV-vis spectral methods and their structures were established by single crystal X-ray diffraction study. The biochemical activity of the complexes towards DNA binding were performed using absorbance and fluorescence titration methods and their mode of binding with calf thymus DNA has been established by viscosity measurement technique.

Sadhukhan, Dipali; Ray, Aurkie; Das, Saurabh; Rizzoli, Corrado; Rosair, Georgina M.; Mitra, Samiran

2010-06-01

154

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

Microsoft Academic Search

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 LMXn·H2O and L2MXn (L=phosphate Schiff base ligand; M=Ag+, Mn2+, Cu2+, Zn2+, Cd2+, Hg2+, or Fe3+ and X=NO3?, Br? or Cl?). The structure of the prepared compounds was investigated using elemental analysis, IR, 1H and 31P

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

2004-01-01

155

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  

Microsoft Academic Search

Complexes of Cu(II) and Ni(II) of the composition [M(L)X] [where M=Ni(II), Cu(II) and X=Cl?, NO3?, CH3COO?] were synthesized with 1,5-dioxo-9,10-diaza-3,ol-tribenzo-(7,6,10,11,14,15) peptadecane, a N2O2 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

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

2011-01-01

156

Synthesis, characterization and biological evaluation of manganese(II), cobalt(II), nickel(II), copper(II), and cadmium(II) complexes with monobasic (NO) and neutral (NN) Schiff bases  

Microsoft Academic Search

New complexes of MnII, CoII, NiII, CuII, and CdII with bis(acetophenone) ethylenediamine and 5-chlorosalicylideneaniline or 5-bromosalicylideneaniline have been prepared and characterized on the basis of elemental analyses, thermogravimetric analyses, magnetic measurements, electronic and i.r. spectra. The antimicrobial activities of the complexes, ligands, control (dimethyl formamide) and metal salts were tested against Salmonella typhi (bacteria), Saccharomyces cerevisae (yeast), and two fungal

Nilesh H. Patel; Hitesh M. Parekh; Mohan N. Patel

2005-01-01

157

Synthesis, characterization, and X-ray crystal structures of metal complexes with new Schiff-base ligands and their antibacterial activities  

Microsoft Academic Search

Two new potentially hexadentate Schiff bases, [H2L] and [H2L], were prepared by condensation of 2-(3-(2-aminophenoxy)naphthalen-2-yloxy)benzenamine with 3,5-di-tert-butyl-2-hydroxy benzaldehyde and o-vanillin, respectively. Reaction of these ligands with cobalt(II) chloride, copper(II) perchlorate, and zinc(II) nitrate gave complexes ML. The ligands and their complexes have been characterized by a variety of physico-chemical techniques. The solid and solution state investigations show that the complexes

Hassan Keypour; Maryam Shayesteh; Reza Golbedaghi; Abdolkarim Chehregani; Allan G. Blackman

2012-01-01

158

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

NASA Astrophysics Data System (ADS)

The metal complexes of Cu(II), Ni(II) and Co(II) with Schiff bases of 3-(2-hydroxy-3-ethoxybenzylideneamino)-5-methyl isoxazole [HEBMI] and 3-(2-hydroxy-5-nitrobenzylidene amino)-5-methyl isoxazole [HNBMI] which were obtained by the condensation of 3-amino-5-methyl isoxazole with substituted salicylaldehydes have been synthesized. Schiff bases and their complexes have been characterized on the basis of elemental analysis, magnetic moments, molar conductivity, thermal analysis and spectral (IR, UV, NMR and Mass) studies. The spectral data show that these ligands act in a monovalent bidentate fashion, co-ordinating through phenolic oxygen and azomethine nitrogen atoms. Chelates of Co(II), Ni(II) appear to be octahedral and Cu(II) appears to be distorted octahedral. To investigate the relationship between formation constants of binary complexes and antimicrobial activity, the dissociation constants of Schiff bases and stability constants of their binary metal complexes have been determined potentiometrically in aqueous solution at 30 ± 1 °C and at 0.1 M KNO 3 ionic strength and discussed. Antimicrobial activities of the Schiff bases and their complexes were screened. The structure-activity correlation in Schiff bases and their metal(II) complexes are discussed, based on the effect of their stability constants. It is observed that the activity enhances upon complexation and the order of activity is in accordance with stability order of metal ions.

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

2008-06-01

159

Synthesis, X-ray crystallography, thermal studies, spectroscopic and electrochemistry investigations of uranyl Schiff base complexes  

NASA Astrophysics Data System (ADS)

Some tetradentate salen type Schiff bases and their uranyl complexes were synthesized and characterized by UV-Vis, NMR, IR, TG, C.H.N. and X-ray crystallographic studies. From these investigations it is confirmed that a solvent molecule occupied the fifth position of the equatorial plane of the distorted pentagonal bipyramidal structure. Also, the kinetics of complex decomposition by using thermo gravimetric methods (TG) was studied. The thermal decomposition reactions are first order for the studied complexes. To examine the properties of uranyl complexes according to the substitutional groups, we have carried out the electrochemical studies. The electrochemical reactions of uranyl Schiff base complexes in acetonitrile were reversible.

Asadi, Zahra; Shorkaei, Mohammad Ranjkesh

2013-03-01

160

A study on copper(II)-Schiff base-azide coordination complexes: Synthesis, X-ray structure and luminescence properties of [Cu(L)(N 3)]X (L = Schiff bases; X = ClO 4, PF 6)  

Microsoft Academic Search

Two Schiff bases N,N?-(bis(pyridin-2-yl)benzylidene)propane-1,3-diamine (pbpd) and N,N?-(bis(pyridin-2-yl)formylidene)butane-1,4-diamine (pfbd) have been prepared and used to synthesize copper(II) complexes. Four complexes of the type [Cu(L)(N3)]X (1–4) [L=pbpd; X=ClO4 (1); L=pbpd; X=PF6 (2); L=pfbd; X=ClO4 (3); L=pfbd; X=PF6 (4)] have been synthesized and characterized on the basis of microanalytical, spectroscopic, magnetic, electrochemical, luminescence and other physicochemical properties. Two representative complexes of the series,

Sk Hafijur Rahaman; Hoong-Kun Fun; Barindra Kumar Ghosh

2005-01-01

161

Coordination geometries and cooperative ordering effects in copper(II) complexes with tridentate Schiff base dianosis IV 1. EPR monocrystal investigation of dipotassium-bis[( ?-isocyanato- N, O)-{ N-salicylidene-( R, S)- ?-alaninato}]dicuprate(II)  

Microsoft Academic Search

Some aspects of the crystal structure of dipotassium-bis[(?-isocyanato-N,O)-{N-salicylidene-(R,S)-?-alaninato}](dicuprate(II), K2[Cu2{sal-R,S-ala}2(?-NCO)2], necessary for the interpretation of EPR monocrystal spectra are reported The crystal structure consists of centrosymmetric binuclear [Cu2{sal-R,S-ala}2(?-NCO)2]2? complex anions connected with the K+ ions by electrostatic forces. The coordination around CuII is approximately square-pyramidal. The basis of the pyramid is formed by the donor atoms O,N,O of the tridentate Schiff

C. Friebel; G. Plesch; V. Kettmann; J. Krätsmár-Šmogrovi?; O. Švajlenová

1997-01-01

162

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

NASA Astrophysics Data System (ADS)

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.

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

2009-04-01

163

Mossbauer spectra of iron carbonyl complexes of aromatic azines and schiff bases  

SciTech Connect

An analysis is presented for the Mossbauer spectral data for a series of new iron carbonal complexes of aromatic azines and Schiff bases. The Mossbauer spectra were obtained on an electrodynamic instrument with a source consisting of Co 57 in chromium. The isomer shifts were related to the center of the sodium nitroprusside doublet. The nature of the substituents at the methylenimino group carbon a tom does not have a significant effect on the Mossbauer spectral parameters of binuclear complexes of iron with nitrogen bridges not containing a nitrogen-nitrogen bond. The ortho-metallated complexes obtained from Schiff bases and aromatic azines have two structurally nonequivalent iron atom positions.

Trusov, V.V.; Maksimov, Y.V.; Nekhaev, A.I.; Tyorin, V.D.

1986-02-01

164

Chiral copper-Schiff base catalyst for asymmetric henry reaction  

Microsoft Academic Search

Five copper-Schiff base complexes were synthesized conveniently from copper(II) acetate monohydrate, salicylaldehydes, and\\u000a amino alcohols. The complexes were shown to be effective as catalysts in the asymmetric Henry reaction affording nitro alkanols\\u000a in up to 98% yield with moderate and good enantiomeric excess (up to ee 38.6%).

Yong-guang Gao; Na Chen; Hua-jiang Wu; Xin-sheng Li

2007-01-01

165

New ionic dinuclear Ir(iii) Schiff base complexes with aggregation-induced phosphorescent emission (AIPE).  

PubMed

Two new ionic dinuclear Ir(iii) Schiff base complexes which are straightforward to synthesise have luminescence quantum yields as high as 37% in neat films. These are the first examples of dinuclear ionic Ir(iii) complexes that display aggregation-induced phosphorescent emission (AIPE). PMID:24852610

Li, Guangfu; Wu, Yong; Shan, Guogang; Che, Weilong; Zhu, Dongxia; Song, Baiqiao; Yan, Likai; Su, Zhongmin; Bryce, Martin R

2014-07-01

166

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

Microsoft Academic Search

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

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

2008-01-01

167

A sandwich-type triple-decker lanthanide complex with mixed phthalocyanine and Schiff base ligands.  

PubMed

A new triple-decker dinuclear sandwich-type dysprosium complex based on both the phthalocyanine ligand and the tetradentate Schiff base ligand was synthesized, which is of interest for synthetic chemistry and also shows single-molecule magnetic behaviour. PMID:23818021

Gao, Feng; Li, Yu-Yang; Liu, Cai-Ming; Li, Yi-Zhi; Zuo, Jing-Lin

2013-08-21

168

THE ISOTROPIC HYPERFINE INTERACTION IN SOME TETRADENTATE SCHIFF-BASE COMPLEXES OF COPPER (II)  

Microsoft Academic Search

The isotropic hyperfine constant is investigated for a series of tetradentate Schiff-base complexes of Copper II. In this series the immediate copper environment is essentially square planar and consists of two oxygen and two nitrogen atoms in cis positions. The constancy of ?, which is proportional to the hyperfine constants, indicates that it is quite independent of ligand substitution, depending

Harry C. Allen Jr; Michele I. Scullane

1978-01-01

169

SYNTHESIS OF THE NEW SCHIFF BASE POLYAZA MACROCYCLES AND THEIR COMPLEXES WITH Cu AND Ni  

Microsoft Academic Search

The new Schiff base macrocycles were synthesized from the condensation of diethylenetriamine or dipropylenetriamine with terephthalaldehyde. The relevant transition metal complexes were then formed with nickel and copper salts after the reduction of the macrocycles. CHN-analysis, IR, NMR, and mass spectroscopies were used for their structure characterization.

D. Habibi; V. Izadkhah

2004-01-01

170

A New Synthetic Route to Macrocyclic Nickel (II) Complexes with Uninegative, Schiff-Base Ligands.  

National Technical Information Service (NTIS)

Two series of nickel(II) complexes containing uninegative, macrocyclic Schiff-base ligands have been prepared via simple condensation reactions. Characterization of the new compounds Ni(AT)X and Ni(TAT)X, where AT is 11,13-dimethyl-1,4,7,10-tetraazacyclot...

S. C. Cummings R. E. Sievers

1969-01-01

171

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

PubMed

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. PMID:18456546

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

2008-12-15

172

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

NASA Astrophysics Data System (ADS)

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.

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

2008-12-01

173

Electron-rich salen-type Schiff base complexes of Cu(II) as catalysts for oxidation of cyclooctene and styrene with tert-butylhydroperoxide: A comparison with electron-deficient ones  

Microsoft Academic Search

Two square planar copper(II) complexes of tetradentate Schiff base ligands derived from aromatic aldehydes and 2,2?-dimethylpropandiamine (H2{salnptn(3-OMe)2}, H2{hnaphnptn}) have been prepared and used as catalysts for oxidation of cyclooctene and styrene with tert-butylhydroperoxide (TBHP). Oxidation of cyclooctene with TBHP gave cyclooctene oxide as the sole product, but in the case of styrene a mixture of styrene oxide and benzaldehyde has

Saeed Rayati; Saeed Zakavi; Marjan Koliaei; Andrzej Wojtczak; Anna Kozakiewicz

2010-01-01

174

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

NASA Astrophysics Data System (ADS)

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

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

175

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

PubMed

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. PMID:24611370

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

2013-12-01

176

Thermal and spectral studies on complexes derived from tetradentate Schiff bases  

Microsoft Academic Search

Several new complexes of Schiff bases ligands H4La and H4Lb with transition metal ions such as Cr(III), Fe(III), Co(II) and Zn(II) are synthesized. Elemental analysis, infrared, UV–Vis\\u000a and thermal analysis, as well as conductivity and magnetic susceptibility measurements are used to elucidate the structure\\u000a of the newly prepared metal complexes. A square planar geometry is suggested for Zn(II) complexes, while

H. M. Abdel-Fattah; A. L. El-Ansary; N. S. Abdel-Kader

2009-01-01

177

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

PubMed

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

Reiss, Aurora; Chifiriuc, Mariana Carmen; Amzoiu, Emilia; Spînu, Cezar Ionu?

2014-01-01

178

Synthesis and spectral characterization of ternary mixed-vanadyl ?-diketonate complexes with Schiff bases  

NASA Astrophysics Data System (ADS)

A new method to synthesize some mononuclear ternary oxovanadium(IV) complexes of the general formula [VO(?-dike)(SB)] (where H?-dike = acetylacetone; benzoylacetone or dibenzoylmethane, HSB = Schiff bases) has been explored by stepwise substitutions of acetylacetonate ion of VO(acac)2 with Schiff bases. The substituted acetylacetone could be fractionated out with p-xylene as an azeotrope. The complexes were characterized by elemental analyses, molecular weight determinations, spectral (electronic, infrared, 1H NMR, EPR and powder XRD) studies, magnetic susceptibility measurements and cyclic voltammetry. Molar conductance measurements indicated the complexes to be non-electrolytes in nitrobenzene. Bidentate chelating nature of ?-diketones and Schiff base anions in the complexes was established by infrared and NMR spectra. Molecular weight determinations confirmed mononuclear nature of the complexes. The EPR spectra illustrated coupling of the unpaired electron with 51V nucleus (I = 7/2). Cyclic voltammograms of all the complexes displayed two-step oxidation processes. The oxidation peak potential corresponded to the quasireversible one-electron oxidation process of the metal center, yielding V(V) species. Transmission electron microscopy (TEM) indicated spherical particles of ˜200 nm diameter. The synthesized complexes are mixed-ligand complexes showing a considerable hydrolytic stability in which vanadium is having coordination number 5. A square pyramidal geometry around vanadium has been assigned in all the complexes.

Baranwal, Balram Prasad; Tripathi, Kiran; Singh, Alok Kumar; Tripathi, Saurabh

2012-06-01

179

Asymmetric Cyclopropanation Catalyzed by a Series of Copper(Schiff-Base) Complexes with Two Chiral Centers  

Microsoft Academic Search

A series of copper-(Schiff-base) complexes with two chiral centers derived from 1,2-diphenyl-2-amino-ethanol were synthesized and applied to catalyze the asymmetric cyclopropanation of ethenes with diazoacetates. A mechanism that can explain the observed results was proposed. Some of these complexes were also efficient catalysts for asymmetric cyclopropanation of 1,1-diphenylethene with ethyl diazoacetate, affording high e.e. of up to 98.6%. An e.e.

Changsheng Jiang; Zhang Ming; Qitao Tan; Dai Qian; Tianpa You

2002-01-01

180

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

PubMed

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

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

2014-01-01

181

COMPLEXES OF COPPER(II) WITH N,N?BIS(4-ANTIPYRYLMETHYLIDENE)ETHYLENEDIAMINE  

Microsoft Academic Search

Copper(II) complexes of the Schiff base N,N?-bis(4-antipyrylmethylidene)ethylenediamine (BAME) having the general formula [Cu(BAME)2]X2 (X=ClO4, NO3, Cl or Br) have been synthesized and characterized by elemental analyses, electrical conductance in non-aqueous solvents, infrared, electronic and EPR spectra as well as magnetic susceptibility measurements. In the complexes, BAME acts as a neutral bidentate ligand coordinating through both azomethine nitrogens. Both anions remain

K. C. Raju; N. T. Madhu; P. K. Radhakrishnan

2002-01-01

182

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

PubMed

Two novel copper(II) complexes with Schiff base of benzimidazole [Cu(L)Cl]2·CH3OH have been synthesized. HL(1) (N-(benzimidazol-2-ymethyl)-5-chlorosalicylideneimine, C15H11ClN3O) and HL(2) (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 ?-? 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 1.81×10(4) (1), 1.37×10(4) (2), 6.27×10(3) (HL(1)) and 3.14×10(3) (HL(2)) 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 HL(1) 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 ?mol L(-1)) and against COLO205 lines (IC50=16.5±3.4 ?mol L(-1)) is much stronger than that of HL(1), which had the potential to develop anti-cancer drug. PMID:24220672

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

2014-03-01

183

Synthetic, spectroscopic and X-ray crystallographic structural study of the monomeric [Cu(pysme)(sac)(MeOH)] and dimeric [Cu(6mptsc)(sac)] 2 complexes [pysme=anion of the pyridine-2-carboxaldehyde Schiff base of S-methyldithiocarbazate, 6mptsc=the anion of the 6-methyl-2-pyridinecarbaldehydethiosemicarbazone and sac=the saccharinate anion  

Microsoft Academic Search

New mixed-ligand copper(II) complexes of empirical formulas [Cu(pysme)(sac) (CH3OH)] and [Cu(6mptsc)(sac)]2 have been synthesized and characterized by conductance, magnetic, IR and electronic spectroscopic techniques. X-ray crystallographic structure analyses of these complexes indicate that in both complexes the copper(II) ions adopt a five-coordinate distorted square-pyramidal geometry with an N3SO donor environment. The Schiff bases are coordinated to the copper(II) ions as

Mohammad Akbar Ali; A. H Mirza; Thahira B. S. A Ravoof; Paul V Bernhardt

2004-01-01

184

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

NASA Astrophysics Data System (ADS)

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).

Selvi, Canan; Nartop, Dilek

2012-09-01

185

Cationic schiff base amphiphiles and their metal complexes: Surface and biocidal activities against bacteria and fungi.  

PubMed

A series of cationic surfactants containing schiff base groups was synthesized by condensation of four fatty amines namely: dodecyl, tetradecyl, hexadecyl and octadecyl amine and 4-diethyl aminobenzaldehyde (1-4), as well as their metal complexes with divalent transition metal ions including Co, Cu and Mn (5-16). The surface activities of the synthesized surfactants were influenced by their chemical structures and the type of the transition metals. The biological activity measurements of the parent cationic schiff bases showed high efficacy against Gram positive and Gram negative bacterial strains and fungi. While on complexation, the biocidal activity was increased remarkably. The biocidal activity of the tested compounds against sulfur reducing bacteria showed promising results in the field of biocide applications. PMID:20167455

Negm, N A; Zaki, M F; Salem, M A I

2010-05-01

186

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

NASA Astrophysics Data System (ADS)

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

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

2013-03-01

187

Synthesis, Mesomorphism, and Spectroscopic Characterization of New Schiff Bases and Their Cu(II), Pd(II) Complexes  

Microsoft Academic Search

New Schiff bases have been prepared from 1,2-dialkyloxy-4-formyl-5-hydroxybenzene and 4,5-diamino-1,2-didodecyloxybenzene. Pd(II) and Cu(II) complexes are obtained with metal Schiff base ratio of 1:1. The new compounds have been characterized by elemental analyses; IR; and, H NMR, C NMR, and mass spectra. The mesomorphic properties of these complexes were investigated by polarizing microscopy and X-ray diffraction analysis. These complexes form columnar

?. Gürol; V. Ahsen

2005-01-01

188

Spin crossover complexes of iron(III) with an N 4 tetradentate Schiff base ligand  

Microsoft Academic Search

Iron(III) complexes of the Schiff base formed from the condensation of 2-aminobenzaldehyde and ethylenediamine, H2amben, were prepared by the reaction of H2amben with iron(III) halides in acetone. Fe(amben)Cl and Fe(amben)Br·H2O exhibit a spin crossover between the 2T and 6A states as shown by magnetic susceptibility measurements, variable temperature Mössbauer spectra, and electron spin resonance at 77 K. Structural investigation of

Greg Brewer; Jerry Jasinski; William Mahany; Leopold May; Sergey Prytkov

1995-01-01

189

Synthesis, characterization, antifungal, antibacterial and DNA cleavage studies of some heterocyclic Schiff base metal complexes  

Microsoft Academic Search

Co(II), Ni(II), Cu(II) and Zn(II) complexes of the Schiff base derived from indole-3-carboxaldehyde and m-aminobenzoic acid were synthesized and characterized by elemental analysis, molar conductance, IR, UV–Vis, magnetic moment, powder XRD and SEM. The IR results demonstrate the bidentate binding mode of the ligand involving azomethine nitrogen and carboxylato oxygen atoms. The electronic spectral and magnetic moment results indicate that

Madhavan Sivasankaran Nair; Dasan Arish; Raphael Selwin Joseyphus

190

Chemistry of rhenium and technetium. II. Schiff base complexes with polyfunctional amino acids  

SciTech Connect

Amino acid Schiff base technetium(V) complexes of salicylaldehyde with l-cysteine, l-serine, l-histodine, l-threonine, l-glutamic acid and l-tryptophan have been preapred by direct reaction and by constituent combination. The amino acid part of the ligands coordinates to the technetium through the carboxylate group, while the other available functional group of the amino acids plays a more minor role as blocking group or in intramolecular bonding. 3 tables.

Du Preez, J.G.H.; Gerber, T.I.A.; Fourie, P.J.; Van Wyk, A.J.

1984-01-01

191

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

Microsoft Academic Search

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

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

2001-01-01

192

Carbenoid insertions into the silicon?hydrogen bond catalyzed by chiral copper (I) schiff base complexes  

Microsoft Academic Search

An asymmetric insertion reaction of ?-diazoesters derived from methyl arylacetates into the silicon-hydrogen bond of silanes was achieved using a copper (I) catalyst associated with a chiral, C2 symmetric Schiff base. Addition of the diazoesters 1 (1 equiv) to the Cu·Lig complex (R,R)-3 (0.1 equiv) in the presence of the silane reagent (1.5 equiv) at ?40° C yielded the corresponding

Les A. Dakin; Scott E. Schaus; Eric N. Jacobsen; James S. Panek

1998-01-01

193

Design, structural elucidation, DNA interaction and antimicrobial activities of metal complexes containing tetraazamacrocyclic Schiff bases  

Microsoft Academic Search

Tetraazamacrocyclic Schiff bases, designed and synthesized from 3-hydroxy-4-nitrobenzylideneacetoacetanilide\\/3-hydroxy-4-nitrobenzylidene-o-acetoacetotoluidide and 1,2-diaminobenzene, are tetradentate ligands and form solid cationic complexes with Cu, Ni, Co, Zn, Mn, and VO salts in ethanol. Microanalytical data, magnetic moment, electronic, IR, Mass, C NMR, H NMR, and electron spin resonance (ESR) techniques were used to characterize the synthesized compounds. Electronic absorption and IR spectra suggest that

N. Raman; A. Sakthivel; K. Rajasekaran

2009-01-01

194

Synthesis, Characterization and Biological Activities of Copper(II). Zmc(II), Iron(II), Iron(III). Cobalt(II), Cobalt(III), and Nickel(II) Complexes of the Schiff Base Derived from D-Glucosamme and 2-Hydroxynaphthaldehyde  

Microsoft Academic Search

Cu(II), Zn(II), Fe(II), Fe(III), Co(II), Co(III). Ni(II) complexes with the Schiff basc derived from D-glucosamine and 2-hydroxynaphthaldehyde (NGH2) were synthesized. These compounds [Cu(II)NG 2H2O, Zn(II)(NGH)2. H2O, Fe(II)NG .2H2O, Fe(III)NG(OAc) .H2O, Co(II)NG .2H2O, Co(III)NG(OAc).H2O and Ni(II)(NGH)2 .4H2O] were characterized by element analyses, conductivity measurements, infrared and electronic spectra. The Schiff base ligand (NGH2) and Zn(II)(NGH)2. H2O were further characterized by H

Hao-Yu Shen; Shu-Yong Liang; Zhi-Feng Luo; Xiang-Cai Bang; Xin-De Zhu

1998-01-01

195

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

SciTech Connect

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.

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

2010-03-15

196

Preferential azido bridging regulating the structural aspects in cobalt(III) and copper(II)–Schiff base complexes: Syntheses, magnetostructural correlations and catalytic studies  

Microsoft Academic Search

A tridentate NNO donor Schiff base ligand [(1Z,3E)-3-((pyridin-2-yl)methylimino)-1-phenylbut-1-en-1-ol=LH] in presence of azide ions coordinates with cobalt(II) and copper(II) ions giving rise to three new coordination complexes [Co2(L)2(?1,1-N3)2(N3)2] (1), [Cu2(L)2(?1,3-N3)]·ClO4 (2) and [(?1,1-N3)2Cu5(?-OL)2(?1,1-N3)4(?1,1,1-N3)2]n (3). The complexes have been characterized by elemental analysis, FT-IR, UV–Vis spectral studies, and single crystal X-ray diffraction studies. These complexes demonstrate that under different synthetic conditions the

Aurkie Ray; Georgina M. Rosair; Guillaume Pilet; Bülent Dede; Carlos J. Gómez-García; Sandra Signorella; Sebastián Bellú; Samiran Mitra

2011-01-01

197

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

Microsoft Academic Search

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

Mala Nath; Nidhee Chaudhary

1998-01-01

198

Anion-controlled Formation of Silver(I) Complexes of A Hexaazamacrocyclic Schiff Base: Synthesis, Structures and Electrochemistry  

Microsoft Academic Search

Six silver(I) complexes of a macrocyclic Schiff Base (L) with different counter anions have been prepared and structurally characterized, where L is a hexaazamacrocyclic Schiff Base derived from the [2 + 2] condensation of terephthalaldehyde and 3-azapentane-1,5-diamine. [Ag2L(NO3)2] (1) crystallizes in the triclinic space group P1, with a = 7.705(7), b = 7.926(5), c = 12.06(1) Å, ? = 90.33(1),

Hai-Liang Zhu; Ye-Xiang Tong; La-Sheng Long; Ming-Liang Tong; Xiao-Ming Chen

1999-01-01

199

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

Microsoft Academic Search

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 (77K) 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,

Udayshankar G.. Singh; Ruth T.. Williams; Keith R.. Hallam; Geoffrey C.. Allen

2005-01-01

200

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

Microsoft Academic Search

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

Udayshankar G. Singh; Ruth T. Williams; Keith R. Hallam; Geoffrey C. Allen

2005-01-01

201

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

SciTech Connect

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.

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

1988-11-16

202

Synthesis and Characterization of Some Indium(III) Complexes of Schiff Bases  

Microsoft Academic Search

Several new indium(III) complexes of Schiff bases having the general formula InCIL [H2L = R(NCH-o-C6H3ROH), R = (CH2)3, CH2C(CH3)2CH2; R = H, 5-OCH3 6-OCH3] were prepared. These complexes were characterized by elemental analysis, conductivity measurement, UV-Vis, IR, NMR and mass spectral data. A square pyramidal structure with an apical chlorine atom was suggested for these complexes.

Cheng-Hsien Lin

1993-01-01

203

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

Microsoft Academic Search

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

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

2010-01-01

204

Coordination chemistry of two new tetraaza Ni(II) and Cu(II) macrocyclic and two new Co(II) and Zn(II) macroacyclic Schiff base complexes containing piperazine moiety: X-ray crystal structures of Ni(II) and Zn(II) complexes  

Microsoft Academic Search

A new potentially tetradentate (N4) Schiff base ligand (L), 1,9,12,20-tetraazatetracyclo[18.2.2.02,7.014,19]tetracosa-2(7),3,5,8,12,14(19),15,17-octaene containing a piperazine moiety is described. Macrocyclic Schiff base complexes, [NiL](ClO4)2 (1) and [CuL](ClO4)2 (2) have been obtained from equimolar amounts of ligand (L) with nickel(II) and copper(II) metal ions. While the equilibrium reaction in the presence of cobalt(II) and zinc(II) metal ions with ligand L in a 1:1 molar

Hassan Keypour; Parisa Arzhangi; Nasibeh Rahpeyma; Majid Rezaeivala; Yalcin Elerman; Hamid Reza Khavasi

2011-01-01

205

Copper (II) complexes of two new oxamidate bis-tetradentate Schiff-base ligands  

Microsoft Academic Search

Two novel symmetrical bis-tetradentate Schiff base ligands, H2L1 and H4L2, have been prepared from the condensation of N,N?-bis (3-aminopropyl) oxamide with pyridine-2-carbaldehyde and pyrrol-2-carbaldehyde, respectively. The ligands react with copper (II) nitrate in basic medium to yield the dinuclear complexes [Cu2L1] (NO3) 2 and [Cu2L2] . [Cu2L1] (NO3) 2 reacts with sodium azide to yield the neutral dinuclear complex [Cu2L1

Jose M. Dominguez-Vera; Natividad Galvez; Jose M. Moreno; Enrique Colacio

1998-01-01

206

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

PubMed Central

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.

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

2013-01-01

207

Antibacterial and Antifungal Studies on Some Schiff Base Complexes of Zinc(II)  

PubMed Central

Two Schiff base ligands L1 and L2 were obtained by the condensation of glycylglycine respectively with imidazole-2-carboxaldehyde and indole-3-carboxaldehyde and their complexes with Zn(II) were prepared and characterized by microanalytical, conductivity measurement, IR, UV-Vis., XRD and SEM. The molar conductance measurement indicates that the Zn(II) complexes are 1 : 1 electrolytes. The IR data demonstrate the tetradentate binding of L1 and tridentate binding of L2. The XRD data show that Zn(II) complexes with L1 and L2 have the crystallite sizes of 53 and 61 nm respectively. The surface morphology of the complexes was studied using SEM. The in vitro biological screening effects of the investigated compounds were tested against the bacterial species Staphylococcus aureus, Escherichia coli, Klebsiella pneumaniae, Proteus vulgaris and Pseudomonas aeruginosa and fungal species Aspergillus niger, Rhizopus stolonifer, Aspergillus flavus, Rhizoctonia bataicola and Candida albicans by the disc diffusion method. A comparative study of inhibition values of the Schiff base ligands and their complexes indicates that the complexes exhibit higher antimicrobial activity than the free ligands. Zinc ions are proven to be essential for the growth-inhibitor effect. The extent of inhibition appeared to be strongly dependent on the initial cell density and on the growth medium.

Joseyphus, R. Selwin

2008-01-01

208

Antibacterial and Antifungal Studies on Some Schiff Base Complexes of Zinc(II).  

PubMed

Two Schiff base ligands L1and L2 were obtained by the condensation of glycylglycine respectively with imidazole-2-carboxaldehyde and indole-3-carboxaldehyde and their complexes with Zn(II) were prepared and characterized by microanalytical, conductivity measurement, IR, UV-Vis., XRD and SEM. The molar conductance measurement indicates that the Zn(II) complexes are 1: 1electrolytes. The IR data demonstrate the tetradentate binding of L1and tridentate binding of L2. The XRD data show that Zn(II) complexes with L1and L2 have the crystallite sizes of 53 and 61nm respectively. The surface morphology of the complexes was studied using SEM. The in vitro biological screening effects of the investigated compounds were tested against the bacterial species Staphylococcus aureus, Escherichia coli, Klebsiella pneumaniae, Proteus vulgaris and Pseudomonas aeruginosa and fungal species Aspergillus niger, Rhizopus stolonifer, Aspergillus flavus, Rhizoctonia bataicola and Candida albicans by the disc diffusion method. A comparative study of inhibition values of the Schiff base ligands and their complexes indicates that the complexes exhibit higher antimicrobial activity than the free ligands. Zinc ions are proven to be essential for the growth-inhibitor effect. The extent of inhibition appeared to be strongly dependent on the initial cell density and on the growth medium. PMID:23990740

Joseyphus, R Selwin; Nair, M Sivasankaran

2008-06-01

209

Anion directed template synthesis of Cu(II) complexes of a N,N,O donor mono-condensed Schiff base ligand: A molecular scaffold forming highly ordered H-bonded rectangular grids  

Microsoft Academic Search

Anion directed, template syntheses of two dinuclear copper(II) complexes of mono-condensed Schiff base ligand Hdipn (4-[(3-aminopentylimino)-methyl]-benzene-1,3-diol) involving 2,4-dihydroxybenzaldehyde and 1,3-diaminopentane were realized in the presence of bridging azide and acetate anions. Both complexes, [Cu2(dipn)2(N3)2] (1) and [Cu2(dipn)2(OAc)2] (2) have been characterized by X-ray crystallography. The two mononuclear units are joined together by basal–apical, double end-on azido bridges in complex 1

Pampa Mukherjee; Oindrila Sengupta; Michael G. B. Drew; Ashutosh Ghosh

2009-01-01

210

Theoretical study of structure and electronic absorption spectra of some Schiff bases and their zinc complexes.  

PubMed

Tetradentate Schiff bases (H(2)L(i)), derivatives of salicylic aldehyde (H(2)L(1), H(2)L(2)) or o-vanillin (H(2)L(3), H(2)L(4)) with ethylenediamine or o-phenylenediamine as a bridge, and their zinc complexes were studied experimentally and theoretically in view of their possible application as emitters in organic light emitting diodes (OLEDs). The composition of thin films of the complexes was analyzed using a combination of different experimental and molecular modeling techniques taking into account changes in the Gibbs free energy of dehydration and dimerization reactions. The absorption spectra of the initial Schiff bases were investigated in methanol solutions, while the absorption spectra of their zinc complexes were investigated in thin films. Experimental results of elemental analysis, IR spectroscopy, laser desorption/ionization mass spectrometry (LDI MS), and X-ray diffraction as well as theoretical analysis of electronic absorption spectra by the quantum-chemical TD DFT method demonstrate that thin films of the zinc complexes contain binuclear anhydrous molecules. This conclusion should be taken into account when considering both transport and luminescence properties of these complexes in OLED heterostructures. A comparison of the results of CIS, TD DFT/PBE, and TD DFT/PBE0 calculations reveals the crucial importance of the inclusion of the exact exchange in the E(XC) functional for the further correct description of potential energy surfaces of excited states for the systems studied. PMID:19891422

Vladimirova, Kseniya G; Freidzon, Alexandra Ya; Kotova, Oxana V; Vaschenko, Andrei A; Lepnev, Leonid S; Bagatur'yants, Alexander A; Vitukhnovskiy, Alexei G; Stepanov, Nickolai F; Alfimov, Michael V

2009-12-01

211

[Di-n-butytin tridentate acylhydrazone Schiff base complexes: synthesis and studies by infrared spectroscopy].  

PubMed

Four tridentate acylhydrazone schiff base ligands H2L [H2L1:C6H5C(O)NHN = CHC6H4OH-2, H2L2:C6H5C(O)NHN = CHC6H3(OH)(2)-2,4, H2L3:NC5H4C(O)NHN = CHC6H4OH-2, H2L4:NC5H4C(O)NHN = CHC6H3(OH)(2)-2,4] were synthesized and use to form four novel di-n-Butytin complexes of the type (n-Bu)2SnL with di-n-Butytin oxide [(n-Bu)2SnO]. All these ligands and complexes were characterized by elemental analysis and infrared spectroscopy. Their principal infrared spectral absorption peaks were assigned and discussed for the region of 4,000-400 cm-1. A comparison of the infrared spectra of the ligands with those of the corresponding complexes reveals that the disappearance of the bands assigned to carbonyl unambiguously confirms that the ligands coordinate with tin in the enol form. The coordination manner for tridentate acylhydrazone schiff base ligands with tin atom in the complexes was determined. The results indicated that the Sn atom in these complexes is five-coordinated. PMID:12939967

Wang, Shao-ling; Lu, Wen-guan; Liu, Hong-wen; Chen, Xiao-kang

2003-02-01

212

Highly Fluorescent BF2 Complexes of Hydrazine-Schiff Base Linked Bispyrrole.  

PubMed

A series of BF2 complexes of hydrazine-Schiff base linked bispyrrole have been prepared from a simple two-step reaction from commercially available substances and are highly fluorescent in solution, film, and solid states with larger Stokes shift and excellent photostabilities comparable or even super to those of their BODIPY analogues. These resultant fluorescent dyes are highly susceptible to the postfunctionalization, as demonstrated in this work via the Knoevenagel condensation to introducing functionalities or tether groups to the chromophore. PMID:24850322

Yu, Changjiang; Jiao, Lijuan; Zhang, Ping; Feng, Zeya; Cheng, Chi; Wei, Yun; Mu, Xiaolong; Hao, Erhong

2014-06-01

213

Preparation of macrocyclic Schiff-base ligand and antibacterial activities of transition metal complexes thereof  

Microsoft Academic Search

A macrocyclic Schiff-base (H2L) ligand is prepared via condensation of 2,6-pyridine dicarboxaldehyde with triethylene tetramine. The ligand is characterized using elemental analysis, by mass spectrometry, infrared (IR) spectroscopy, and proton nuclear magnetic resonance spectroscopy. The corresponding 1:1 metal complexes with Cr(III), Fe(III), Co(II), Ni(II), Cu(II), Cd(II), UO2(II), and Th(IV) are additionally characterized by determining their magnetic moment, molar conductance, thermal

Gehad G. Mohamed; Mohamed M. Omar; Mohsen S. Abou El-Ela; Ahmed M. M. Hindy

2011-01-01

214

Cu II acetate complexes involving N,N,O donor Schiff base ligands: Monoatomic oxygen bridged dimers and alternating chains of the dimers and Cu 2(OAc) 4  

Microsoft Academic Search

Two tridentate N,N,O donor Schiff bases, HL1 (4-(2-ethylamino-ethylimino)-pentan-2-one) and HL2 (3-(2-amino-propylimino)-1-phenyl-butan-1-one) on reaction with CuII acetate in presence of triethyl amine yielded two basal-apical, mono-atomic acetate oxygen-bridging dimeric copper(II) complexes, [Cu2L12(OAc)2] (1), [Cu2L22(OAc)2] (2). Whereas two other similar tridentate ligands HL3 (4-(2-amino-propylimino)-pentane-2-one) and HL4 (3-(2-amino-ethylimino)-1-phenyl-butan-1-one) under the same conditions produced a mixture of the corresponding dimers and a one-dimensional alternating

Biswarup Sarkar; Michael G. B. Drew; Marta Estrader; Carmen Diaz; Ashutosh Ghosh

2008-01-01

215

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)

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.

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

2014-01-01

216

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

SciTech Connect

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.

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

1993-12-31

217

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

NASA Astrophysics Data System (ADS)

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.

Hanif, Muhammad; Chohan, Zahid H.

2013-03-01

218

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

NASA Astrophysics Data System (ADS)

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

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

2014-01-01

219

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

PubMed

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. PMID:24309180

Mohammadi, Khosro; Niad, Mahmood; Jafari, Tahereh

2014-03-25

220

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

PubMed Central

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

Mishra, A. P.; Soni, Monika

2008-01-01

221

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

NASA Astrophysics Data System (ADS)

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.

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

2011-09-01

222

Synthesis, spectral and magnetic studies of mono- and bi-nuclear metal complexes of a new bis(tridentate NO 2) Schiff base ligand derived from 4,6-diacetylresorcinol and ethanolamine  

Microsoft Academic Search

A new bis(tridentate NO2) Schiff base ligand, H4L, was prepared by the reaction of the bifunctional carbonyl compound; 4,6-diacetylresorcinol (DAR) with ethanolamine. The ligand reacted with iron(III), cobalt(II), nickel(II), copper(II), zinc(II), cadmium(II), cerium(III) and uranyl(VI) ions, in absence and in presence of LiOH, to yield mono- and bi-nuclear complexes with different coordinating sites. The ligand and its metal complexes were

Magdy Shebl

2009-01-01

223

Prepared and characterization of new macrocyclic Schiff bases and their binuclear copper complexes  

Microsoft Academic Search

The new five macrocyclic ligands were synthesized by reaction of 2,6-diaminopyridine and various dialdehydes. Then, their copper(II) perchlorate complexes were synthesized by template effect by reaction of 2,6-diaminopyridine, Cu(ClO4)2·6H2O and aldehydes. The ligands and their complexes have been characterized by elemental analysis, IR, 1H and 13C NMR, UV–vis spectra, magnetic susceptibility, conductivity measurements, mass spectra. All complexes are diamagnetic and

Hamdi Temel; Salih Ilhan

2008-01-01

224

Spectroscopic and electrochemical characterization of some Schiff base metal complexes containing benzoin moiety  

NASA Astrophysics Data System (ADS)

The ligation behavior of bis-benzoin ethylenediamine (B2ED) and benzoin thiosemicarbazone (BTS) Schiff bases towards Ru3+, Rh3+, Pd2+, Ni2+ and Cu2+ were determined. The bond length of M-N and spectrochemical parameters (10Dq, ?, B and LFSE) of the complexes were evaluated. The redox characteristics of selected complexes were explored by cyclic voltammetry (CV) at Pt working electrode in non aqueous solvents. Au mesh (100 w/in.) optically transparent thin layer electrode (OTTLE) was also used for recording thin layer CV for selected Ru complex. Oxidation of some complexes occurs in a consecutive chemical reaction of an EC type mechanism. The characteristics of electron transfer process of the couples M2+/M3+ and M3+/M4+ (M = Ru3+, Rh3+) and the stability of the complexes towards oxidation and/or reduction were assigned. The nature of the electroactive species and reduction mechanism of selected electrode couples were assigned.

El-Shahawi, M. S.; Al-Jahdali, M. S.; Bashammakh, A. S.; Al-Sibaai, A. A.; Nassef, H. M.

2013-09-01

225

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

PubMed

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. PMID:23116556

Sumrra, Sajjad H; Chohan, Zahid H

2013-12-01

226

Complexes of technetium(V) with potentially tridentate schiff bases derived from s-methyldithiocarbazate  

SciTech Connect

The syntheses and characterization of several new neutral oxotechnetium(V) complexes with potentially dianionic tridentate Schiff bases, derived from S-methyldithiocarbazate, are described. For a 1:1 metal ion to ligand ratio the five-coordinate complexes TcOLCl were isolated in all cases. Only in one case could a six-coordinate TcOL/sub 2/Cl, with the ligand acting as a bidentate chelate, be isolated from a 1:2 metal ion to ligand ratio. Magnetic susceptibility measurements of the complex TcO(HAF)Cl surprisingly indicate paramagnetism with a d/sup 2/ electronic configuration, while all the other compounds were found to be diamagnetic. The relative strength of the Tc=O bond is mainly determined by the electronic influence of the cis-ligands. The complexes have been characterized by elemental analyses, infrared and electronic spectra, and conductance measurements.

DuPreez, J.G.H.; Gerber, T.I.A.; Knoesen, O.

1987-01-01

227

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

PubMed

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. PMID:24390488

Rîmbu, Cristina; Danac, Ramona; Pui, Aurel

2014-01-01

228

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

NASA Astrophysics Data System (ADS)

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

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

2013-11-01

229

Efficient Water Oxidation Catalyzed by Mononuclear Ruthenium(II) Complexes Incorporating Schiff Base Ligands.  

PubMed

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 )2 Ce(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. PMID:24888489

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

230

Double-stranded monohelical complexes from an unsymmetrical chiral Schiff-base ligand.  

PubMed

A new Schiff-base ligand is prepared by a two-step reaction of 3-formylsalicylic acid and (1R, 2R)-diaminocyclohexane in alcoholic solvents. The 1:1 condensation product exists as a zwitterion in the solid state and forms pleated hydrogen-bonded sheets. Metalation of the ligand with divalent iron, nickel, cobalt, and zinc resulted in the formation of double-stranded monohelices with exclusively M-helicity. Each complex has two tridentate ligands, with the carboxylic acid groups remaining uncoordinated. In the crystal lattice, these complexes form extended M-helical strands through intermolecular hydrogen bonding interactions. Metalation of the ligand with copper salts resulted in a distinctly different type of complex, in which the ligand has transformed into a symmetric tetradentate salen ligand with uncoordinated carboxylic acid groups. PMID:18166045

Lalehzari, Azadeh; Desper, John; Levy, Christopher J

2008-02-01

231

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

NASA Astrophysics Data System (ADS)

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

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

2014-04-01

232

Complexes of divalent transition metal chlorides with the tetradentate Schiff base ligand 1,2-bis(2?-pyridylmethyleneimino)-benzene  

Microsoft Academic Search

Transition metal(II) chloro complexes of the new Schiff base ligand 1,2-bis(2'-pyridylmethyleneimino)benzene (L), derived from 2-pyridinecarboxaldehyde and 1,2-phenylenediamine, were prepared. Compounds of [MnLCl2]-H2O, [CoLCl2]·2H2O, [NiLCl2] and [Zn3L2Cl4]Cl2 were prepared. Details are given of the formation of the complex [Cu(L·EtOH)Cl2], in which one molecule of EtOH adds across only one of the Schiff base {ie531-01} groups to give the coordinated ligand L·EtOH.

Spyridoula Kasselouri; Achilleas Garoufis; George Kalkanis; Spyros P. Perlepes; Nick Hadjiliadis

1993-01-01

233

Self-assembling dicopper(II) complexes of di-2-pyridyl ketone Schiff base ligands derived from S-alkyldithiocarbazates  

Microsoft Academic Search

Condensation of di-2-pyridyl ketone with S-methyldithiocarbazate or S-benzyldithiocarbazate yields potentially bridging ligands of the form Py2CNNHC(S)SR; Hdpksme (R=Me; the di-2-pyridyl ketone Schiff base of S-methyldithiocarbazate) and Hdpksbz (R=Bz; the di-2-pyridyl ketone Schiff base of S-benzyldithiocarbazate). Complexation of these ligands with Cu(II) in a 1:1M ratio leads to the formation of dinuclear complexes of the general formula [Cu(NNNS)X]2 (X=Cl?, NO3?, H2O).

Mohammad Akbar Ali; Aminul H. Mirza; Ray J. Butcher; Paul V. Bernhardt; Mohammad Rezaul Karim

2011-01-01

234

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

PubMed

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(2)O and L(2)MX(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 aeruginosa, Klebsiella pneumoniae, 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. PMID:14670488

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

2004-01-01

235

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

PubMed

Fluorescence spectroscopy in combination with circular dichroism (CD) spectroscopy were used to investigate the interaction of water-soluble amino acid Schiff base complexes, [Zn(L1,2)(phen)] where phen is 1,10-phenanthroline and H2L1,2 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 DeltaG, DeltaH and DeltaS at different temperatures (298, 310 and 318K) were calculated. The results indicate that the hydrophobic and hydrogen bonding interactions play a major role in [Zn(L1)(phen)]-BSA association, whereas hydrophobic and electrostatic interactions participate a main role in [Zn(L2)(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 (f(alpha), f(beta), f(turn) and f(random)) 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 design. PMID:18701343

Gharagozlou, Mehrnaz; Boghaei, Davar M

2008-12-15

236

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

PubMed

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 (1)H 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, (1)H 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

Abou-Hussein, Azza A; Linert, Wolfgang

2014-01-01

237

Synthesis, structure, DNA binding, and cleavage activity of two copper(II) complexes  

Microsoft Academic Search

Two copper(II) complexes, [Cu2(L)2(H2O)]? (1) and {[Cu2(L)2(H2O)]?·?H2O}? (2), have been synthesized and characterized by elemental analysis, UV-visible absorption spectra, and single-crystal X-ray diffraction. H2L is an amino acid Schiff base derived from condensation of N-(2-hydroxybenzaldehyde) and L-methionine. H2L is a reduced product of H2L by sodium borohydride (scheme 1). Both complexes consist of one-dimensional covalently bonded polymeric chains. Complex 1 has

Chunyan Gao; Xiaofang Ma; Jing Lu; Zhigang Wang; Jinlei Tian; Shiping Yan

2011-01-01

238

The effect of donor groups and geometry on the redox potential of copper Schiff base complexes  

Microsoft Academic Search

We report a study which correlates the metrical parameters of the unsubstituted tetradentate copper Schiff base complexes containing N2O2, N2N2 and N2S2 donors with their respective redox potentials. To achieve this aim we were required to structurally characterise many of the seminal species including, [CuAmbpr-H2], [CuH4Amben][ClO4]2, [CuH4Ambpr][ClO4]2, [CuH4Ambbu][ClO4]2, CuH4Salpr and [Cu(SSalen)2][ClO4]2 which were absent from the crystallographic catalogue. The oxidative

Michelle K. Taylor; John Reglinski; Leonard E. A. Berlouis; Alan R. Kennedy

2006-01-01

239

X-ray and DFT studies of a mono- and binuclear copper(II) ionic compound containing a Schiff base.  

PubMed

In the structure of trans-bis(ethanol-?O)tetrakis(1H-imidazole-?N(3))copper(II) bis[?-N-(2-oxidobenzylidene)-D,L-glutamato]-?(4)O(1),N,O(2'):O(2');?(4)O(2'):O(1),N,O(2')-bis[(1H-imidazole-?N(3))cuprate(II)], [Cu(C(3)H(4)N(2))(4)(C(2)H(6)O)(2)][Cu(2)(C(15)H(14)N(3)O(5))(2)], both ions are located on centres of inversion. The cation is mononuclear, showing a distorted octahedral coordination, while the anion is a binuclear centrosymmetric dimer with a square-pyramidal copper(II) coordination. An extensive three-dimensional hydrogen-bonding network is formed between the ions. According to B3LYP/6-31G* calculations, the two equivalent components of the anion are in doublet states (spin density located mostly on Cu(II) ions) and are coupled as a triplet, with only marginal preference over an open-shell singlet. PMID:23124455

Langer, Vratislav; Mach, Pavol; Gyepesová, Dalma; Andrezálová, Lucia; Kohútová, Mária

2012-11-01

240

Electroreduction of a Binuclear Macrocyclic Complex of Copper(II) of the Robson Type in Aqueous Solutions  

Microsoft Academic Search

The electroreduction of a binuclear complex of copper(II) with a macrocyclic Schiff base of the Robson type on the basis of 4-tert-butyl-2,6-diformylphenol and 1,3-diaminopropane on the dropping-mercury, gold, amalgamated-gold, and glassy-carbon electrodes is studied in an aqueous environment. The data of experiments on preparative electrolysis and the results of measurements by a method of cyclic voltammetry and classic polarography suggest

N. V. Roznyatovskaya; G. A. Tsirlina; V. V. Roznyatovskii; M. D. Reshetova; Yu. A. Ustynyuk

2004-01-01

241

Characteristic spectral studies and in vitro antifungal activity of some Schiff bases and their organotin (IV) complexes  

Microsoft Academic Search

The synthesis andin vitro antifungal activity of some Schiff bases and their Sn (IV) complexes has been tested against plant pathogenic fungi and it\\u000a is found that they possess excellent fungicidal activity. On the basis of1H-,13C-,119Sn NMR-,119Sn Mössbauer, IR and Elemental analysis the tetrahedral geometry is proposed for the synthesized compounds.

Wajid Rehman; Musa Kaleem Baloch; Bakhtiar Muhammad; Amin Badshah; Khalid M. Khan

2004-01-01

242

Self-assembly of a 15-nickel metallamacrocyclic complex derived from the L-glutamic acid Schiff base ligand.  

PubMed

An intriguing 15-nickel metallamacrocyclic complex, [Ni15(EVan)10(H2O)20], (EVan = Schiff base formed between l-glutamic acid and o-vanillin), has been synthesized and characterized by single-crystal X-ray diffraction and spectroscopic analyses. adopts a Ni-O-Ni-O-Ni-O configuration and can be divided into five discrete trinuclear units. PMID:24615170

Thio, Yude; Toh, Shi Wei; Xue, Feng; Vittal, Jagadese J

2014-04-28

243

Structural and biological behaviors of some nonionic Schiff-base amphiphiles and their Cu(II) and Fe(III) metal complexes.  

PubMed

Novel series of nonionic Schiff bases was synthesized and characterized using microelemental analysis, FTIR and (1)H NMR spectra. These Schiff bases and their complexes with Cu and Fe have been evaluated for their antibacterial activity against bacterial species such as Staphylococcus aureus, Pseudomonas aureus, Candida albi, Bacillus subtilis and Escherichia coli and their fungicidal activity against Aspcrgillus niger and Aspcrgillus flavus. The results of the biocidal activities showed high potent action of the synthesized Schiff bases towards both bacteria and fungi. Furthermore, complexation of these Schiff bases by Cu(II) and Fe(III) show the metal complexes to be more antibacterial and antifungal than the Schiff bases. The results were correlated to the surface activity and the transition metal type. The mode of action of these complexes was discussed. PMID:18325743

Negm, Nabel A; Zaki, Mohamed F

2008-07-15

244

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)

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.

Arish, D.; Nair, M. Sivasankaran

2011-11-01

245

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

PubMed

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(2)X(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, (1)H and (13)C-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(2)Cl(2) complex exhibits tremendous antimicrobial, DNA binding and cleaving properties. PMID:21855399

Arish, D; Nair, M Sivasankaran

2011-11-01

246

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)

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

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

2013-03-01

247

Spectroscopic and magnetic studies on some copper (II) complexes of antipyrine Schiff base derivatives  

Microsoft Academic Search

A new series of copper(II) complexes derived from 4-(2-thienyl-methylidene amino) antipyrine (TAAP) and 4-furfurylidene amino antipyrine (FAAP) have been synthesized. The complexes are formulated as [(TAAP)Cu](ClO4)2, [(FAAP)2Cu](ClO4)2, [(FAAP)Cu(OH)Br], [L2CUX2]·nH2O and [L2Cu(NO3)2], L ? TAAP or FAAP, X ? Cl or Br and n = 2 or 1, based on their elemental analyses and infrared spectral data. The infrared data indicate

Kamal Z. Ismail; Ali El-Dissouky; Aziza Z. Shehada

1997-01-01

248

DNA binding and nuclease activity of an oxovanadium valinato-Schiff base complex.  

PubMed

A new oxovanadium complex [VO(sal-l-val)(phen)] (sal-l-val=Schiff base derived from salicylaldehyde and l-valine; phen=1,10-phenanthroline) has been designed and synthesized with the aim of developing potential DNA nuclease. The interaction of DNA with this structurally characterized oxovanadium complex has been studied by various physicochemical tools like UV-vis, fluorescence, viscosity and circular dichroism (CD). The intrinsic binding constant of the complex with DNA is determined by electronic absorption studies and calculated to be (4.74±0.02)×10(5)M(-1). The spectroscopic studies and the viscosity measurements indicate that the complex binds calf thymus DNA (CT-DNA) by intercalative mode. The ability of the complex to induce DNA cleavage was studied by gel electrophoresis techniques. The complex has been found to promote cleavage of pUC19 plasmid DNA from the super coiled (SC) form I to nicked coiled (NC) relaxed form II with good efficiency. PMID:24560950

Saha, Urmila; Mukherjea, Kalyan K

2014-05-01

249

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

PubMed

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, (1)H NMR, (13)C 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. PMID:21993257

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

2011-12-15

250

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

SciTech Connect

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.

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

1998-09-07

251

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

NASA Astrophysics Data System (ADS)

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.

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

2014-06-01

252

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

PubMed

The [Co(Me2Salen)(PBu3)(OH2)]BF4 and [Co(Me2Salen)(PPh3)(Solv)]BF4, complexes were synthesized and characterized by FT-IR, UV-Vis, (1)H 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. PMID:24637279

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

2014-06-01

253

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

PubMed

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

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

2013-12-21

254

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

PubMed

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

Raman, N; Sakthivel, A; Pravin, N

2014-05-01

255

Synthesis, characterization, biological and catalytic applications of transition metal complexes derived from Schiff base.  

PubMed

A novel series of Cu(II), Ni(II), Zn(II), Co(II), and Cd(II) complexes have been synthesized from the Schiff base. Structural features were determined by analytical and spectral techniques like IR, (1)H NMR, UV-vis, elemental analysis, molar electric conductibility, magnetic susceptibility and thermal studies. The complexes are found to be soluble in dimethylformamide and dimethylsulfoxide. Molar conductance values in dimethylformamide indicate the non-electrolytic nature of the complexes. Binding of synthesized complexes with calf thymus DNA (CT DNA) was studied. There is significant binding of DNA in lanes 2, 3, and 5. Lanes 4 and 6 are showing more florescence when compared to the control indicating that these molecules are strongly bound to the DNA by inserting themselves between the two stacked base pairs and exhibiting their original property of fluorescence. Angiogenesis study has revealed that the compounds B-2, B-4 and B-5 have potent antitumor efficacy and activation of antiangiogenesis could be one of the possible underlying mechanisms of tumor inhibition. PMID:24915881

Bushra Begum, A; Rekha, N D; Vasantha Kumar, B C; Lakshmi Ranganatha, V; Khanum, Shaukath Ara

2014-08-01

256

Tetradentate Schiff base ligands and their complexes: Synthesis, structural characterization, thermal, electrochemical and alkane oxidation  

NASA Astrophysics Data System (ADS)

Three Schiff base ligands (H2L1-H2L3) with N2O2 donor sites were synthesized by condensation of 1,5-diaminonapthalene with benzaldehyde derivatives. A series of Cu(II), Co(II), Ni(II), Mn(II) and Cr(III) complexes were prepared and characterized by spectroscopic and analytical methods. Thermal, electrochemical and alkane oxidation reactions of the ligands and their metal complexes were investigated. Extensive application of 1D (1H, 13C NMR) and 2D (COSY, HETCOR, HMBC and TOSCY) NMR techniques were used to characterize the structures of the ligands and establish the 1H and 13C resonance assignments of the three ligands. Ligands H2L1 and H2L3 were obtained as single crystals from THF solution and characterized by X-ray diffraction. Both molecules are centrosymmetric and asymmetric unit contains one half of the molecule. Catalytic alkane oxidation reactions with the transition metal complexes investigated using cyclohexane and cyclooctane as substrates. The Cu(II) and Cr(III) complexes showed good catalytic activity in the oxidation of cyclohexane and cyclooctane to desired oxidized products. Electrochemical and thermal properties of the compounds were also investigated.

Ceyhan, Gökhan; Köse, Muhammet; McKee, Vickie; Uru?, Serhan; Gölcü, Ay?egül; Tümer, Mehmet

257

Luminescence and structural properties of lanthanide complexes of Schiff bases derived from pyridoxal and amino acids.  

PubMed

Lanthanide complexes of Schiff bases (SBs) with 1:1 and 1:2 (M:Lig) stoichiometric ratios were prepared by condensation of pyridoxal (PL) and aspartic acid (Asp) or l-histidine (His), respectively, in the presence of the appropriate metal chloride as a templating agent. These complexes were studied by optical spectroscopy and single crystal X-ray diffraction techniques. Crystallographic studies of 1:1 ([Eu(PL-Asp)(H(2)O)(4)](H(2)O)) and 1:2 ([Eu(PL-His)(2)(H(2)O)(2)]Cl(H(2)O)(4)) complexes show that Eu(III) is eight-coordinate in both structures, in a distorted square antiprism environment formed by the phenolic oxygen of PL, the nitrogen atom of carbon-nitrogen double bond, oxygen atoms of the carboxylate groups of His or Asp, and oxygen atoms of the water molecules. The main species formed in aqueous solutions containing these SBs have been determined by analysis of the luminescence spectra, lifetimes of Eu(III) excited states and vibronic interaction as well as structural features of the Eu(III) coordination sphere. Possible tetradentate coordination function of SBs in aqueous solutions with relatively high concentrations as well as the potential application of the lanthanide SB complexes as new luminescence materials are discussed. PMID:17828370

Puntus, Lada; Zhuravlev, Konstantin; Lyssenko, Konstantin; Antipin, Mikhail; Pekareva, Irina

2007-09-28

258

Tetradentate Schiff base ligands and their complexes: synthesis, structural characterization, thermal, electrochemical and alkane oxidation.  

PubMed

Three Schiff base ligands (H(2)L(1)-H(2)L(3)) with N(2)O(2) donor sites were synthesized by condensation of 1,5-diaminonapthalene with benzaldehyde derivatives. A series of Cu(II), Co(II), Ni(II), Mn(II) and Cr(III) complexes were prepared and characterized by spectroscopic and analytical methods. Thermal, electrochemical and alkane oxidation reactions of the ligands and their metal complexes were investigated. Extensive application of 1D ((1)H, (13)C NMR) and 2D (COSY, HETCOR, HMBC and TOSCY) NMR techniques were used to characterize the structures of the ligands and establish the (1)H and (13)C resonance assignments of the three ligands. Ligands H(2)L(1) and H(2)L(3) were obtained as single crystals from THF solution and characterized by X-ray diffraction. Both molecules are centrosymmetric and asymmetric unit contains one half of the molecule. Catalytic alkane oxidation reactions with the transition metal complexes investigated using cyclohexane and cyclooctane as substrates. The Cu(II) and Cr(III) complexes showed good catalytic activity in the oxidation of cyclohexane and cyclooctane to desired oxidized products. Electrochemical and thermal properties of the compounds were also investigated. PMID:22571942

Ceyhan, Gökhan; Köse, Muhammet; McKee, Vickie; Uru?, Serhan; Gölcü, Ay?egül; Tümer, Mehmet

2012-09-01

259

The synthesis and characterization of mono and dinuclear group 13 complexes derived from a Schiff base.  

PubMed

The coordination preferences of the tetradentate Schiff base, N,N'-ethylenebis(acetylacetoimine), H(2)L, with a variety of group 13 precursors, led to the formation of a series of mono and binuclear products. The reaction of H(2)L with AlMe(3) and Me(2)GaCl afforded the binuclear complexes, [L{Al(Me)(2)}(2)] 1 and [H(2)L{GaCl(Me)(2)}(2)], 3, the latter an adduct of the neutral ligand. Treatment of 1 with iodine generated the cationic Al(III) complex, [LAl(thf)(2)]I, 2, while the addition of n-BuLi to H(2)L, followed by reaction with GaCl(3) and InCl(3) led to an ionic complex [{LGaCl}(2)(?Li)]GaCl(4), 4, an In(III) dimer, [LInCl](2), 5 and monomeric [LInCl(thf)], 6. In contrast, the reaction of [In{N(SiMe(3))(2)}(3)] with H(2)L yielded a homoleptic, air stable, indium complex, [L(3)In(2)], 7. All products were definitively characterized by X-ray crystallography and their structures confirmed by pertinent spectroscopic techniques. PMID:22653153

Aprile, Antonino; Wilson, David D J; Richards, Anne F

2012-07-28

260

Copper(II) complexes containing a CuN4O2 coordination sphere assembled via pyridine-imine-amide coordination: Synthesis, structure and properties  

Microsoft Academic Search

Copper(II) complexes [CuL2] of pyridine-N, imine-N and amide-O donor Schiff bases (HL) are reported. The Schiff bases Hpabh, Hpamh and Hpadh were prepared by condensation of 2-pyridinecarboxaldehyde with benzhydrazide, 4-methoxybenzhydrazide and 4-dimethylaminobenzhydrazide, respectively. The complexes were synthesised in MeOH media by reacting Cu(OAc)2 · H2O with HL in a 1:2 mole ratio. The X-ray structure of [Cu(pabh)2] was determined. The

Satyanarayan Pal; Jally Pushparaju; Nimma Rajaiah Sangeetha; Samudranil Pal

2000-01-01

261

Mixed (phthalocyaninato)(Schiff-base) di-dysprosium sandwich complexes. Effect of magnetic coupling on the SMM behavior.  

PubMed

Reaction between Schiff-base ligand and half-sandwich complex M(Pc)(acac) led to the isolation of new sandwich-type mixed (phthalocyaninato)(Schiff-base) di-lanthanide compounds M2(Pc)2(L)H2O (M = Dy, Gd) (1, 2) [H2Pc = metal free phthalocyanine, Hacac = acetylacetone, H2L = N,N'-bis(3-methyloxysalicylidene)benzene-1,2-diamine] with the triple-decker molecular structure clearly revealed by single crystal X-ray diffraction analysis. For the comparative studies, sandwich triple-decker analogues with pure Schiff-base ligand M2(L)3H2O (M = Dy, Gd) (3, 4) were also prepared. Dynamic magnetic measurement result reveals the single-molecule magnet (SMM) nature of the di-dysprosium derivative 1, while the static magnetic investigation over both pure and the diamagnetic diluted samples of this compound discloses the interionic ferromagnetic coupling between the two dysprosium ions, which in turn effectively suppresses the QTM and enhances the energy barrier of this SMM. Nevertheless, comparative studies over the static magnetic properties of the di-dysprosium triple-decker complexes 1 and 3 indicate the stronger magnetic coupling between the two lanthanide ions in mixed (phthalocyaninato)(Schiff-base) species than in the pure Schiff-base triple-decker analogue, suggesting the special coordination sphere around the dysprosium ions in the former compound over the latter one on the more intense inter-ionic ferromagnetic coupling. As a very small step towards understanding the structure-property relationship, the present result will be surely helpful for the design and synthesis of the multinuclear lanthanide-based SMMs with good properties. PMID:24005576

Wang, Hailong; Liu, Chenxi; Liu, Tao; Zeng, Suyuan; Cao, Wei; Ma, Qi; Duan, Chunying; Dou, Jianmin; Jiang, Jianzhuang

2013-11-21

262

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

PubMed

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. PMID:23983671

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

2013-01-01

263

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

PubMed Central

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.

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

2013-01-01

264

Charge transfer complexes of adenosine-5'-monophosphate and cytidine-5'-monophosphate with water-soluble cobalt(II) Schiff base complexes in aqueous solution.  

PubMed

Water-soluble cobalt(II) tetradentate Schiff base complexes have been shown to form charge transfer (CT) complexes with a series of nucleoside monophosphates including adenosine-5'-monophosphate (AMP) and cytidine-5'-monophosphate (CMP). The investigated water-soluble cobalt(II) Schiff base complexes are (i) disodium[{bis(5-sulfo-salicylaldehyde)-o-phenylenediiminato}cobalt(II)], Na2[Co(SO3-salophen)] (1); (ii) disodium[{bis(5-sulfo-salicylaldehyde)-4,5-dimethyl-o-phenylenediiminato}cobalt(II)], Na2[Co(SO3-sal-4,5-dmophen)] (2) and (iii) disodium[{bis(4-methoxy-5-sulfo-salicylaldehyde)-4,5-dimethyl-o-phenylenediiminato}cobalt(II)], Na(2)[Co(SO3-4-meosal-4,5-dmophen)] (3). The formation constant and thermodynamic parameters for charge transfer complex formation of water-soluble cobalt(II) Schiff base complexes with nucleoside monophosphates were determined spectrophotometrically in aqueous solution at constant ionic strength (I = 0.2 mol dm(-3) KNO3) under physiological condition (pH 7.0) and at various temperatures between 288 and 308 K. The stoichiometry has been found to be 1:1 (water-soluble cobalt(II) Schiff base complex: nucleoside monophosphate) in each case. Our spectroscopic and thermodynamic results show that the interaction of water-soluble cobalt(II) Schiff base complexes with the investigated nucleoside monophosphates occurs mainly through the phosphate group. The trend of the interaction according to the cobalt(II) Schiff base complexes due to electronic and steric factors is as follows: Na2[Co(SO3-salophen)] > Na2[Co(SO3-sal-4,5-dmophen)] > Na2[Co(SO3-4-meosal-4,5-dmophen)]. Also the trend of the interaction of a given cobalt(II) Schiff base complex according to the nucleoside monophosphate is as follows: CMP > AMP. PMID:15950536

Boghaei, Davar M; Gharagozlou, Mehrnaz

2006-01-01

265

Two novel compartmental macrocyclic dinuclear copper(II) complexes with ? 2Cl and ? 2-OAc bridges  

Microsoft Academic Search

Two novel compartmental macrocyclic dinuclear copper(II) complexes with different bridging ligands, formulated as [Cu2II(L)(?2-Cl)]·1.5(H2O) (1) and [Cu2II(L)(?2-OAc)]·(DMF) (2), are characterized by X-ray single-crystal diffraction where LH3 is a pentadentate ligand obtained from the Schiff base condensation between 3,5-di-tert-butyl-2-hydroxybenzaldehyde and 2,6-bis(aminomethyl)-4-chlorophenol in a molar ratio of 2:1. Due to the use of different bridges and bulky t-bu groups, different molecular conformation

Zhaolian Chu; Wei Huang

2008-01-01

266

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

SciTech Connect

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.

Jurisson, S.S.

1982-01-01

267

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

SciTech Connect

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.

Brown, L.S.; Varo, G.; Lanyi, J.K. [Univ. of California, Irvine, CA (United States)] [and others

1995-10-03

268

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

PubMed

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 ?(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 ?-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. PMID:22939284

Singh, Atresh Kumar; Singh, Alok Kumar

2012-10-01

269

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

PubMed

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

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

2014-09-15

270

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

NASA Astrophysics Data System (ADS)

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 ?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 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 ?-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.

Singh, Atresh Kumar; Singh, Alok Kumar

2012-10-01

271

Synthesis, crystal structure and magnetic properties of nickel(II) and cobalt(III) complexes of a pentadentate Schiff base  

NASA Astrophysics Data System (ADS)

Two new Schiff base complexes, [Ni2(HL)2(?1,3-N3)]ClO4·H2O (1) and [Co(L)(N3)] (2) where L = 2,2'-{(methylimino)bis[propane-3,1-diylnitrilomethylylidene]}diphenolate ion, have been synthesized by the reaction of equimolar amounts of nickel(II) or cobalt(II) perchlorate with the pentadentate Schiff base ligand (H2L) in presence of azide ion. The complexes have been characterized by microanalytical, spectroscopic, single crystal X-ray diffraction and other physicochemical studies. Structural studies reveal that 1 is an end-to-end azido-bridged binuclear complex in which each nickel(II) adopts irregular octahedral geometry. In contrast, 2 is a mononuclear octahedral cobalt(III) complex containing the azide ion in one of its apical positions. Low temperature magnetic measurements on 1 indicate noticeable intradimer ferromagnetic interactions.

Layek, Manas; Ghosh, Mahendra; Sain, Saugata; Fleck, Michel; Muthiah, Packianathan Thomas; Jenniefer, Samson Jegan; Ribas, Joan; Bandyopadhyay, Debasis

2013-03-01

272

Synthesis, spectroscopic characterization and antibacterial activity of new cobalt(II) complexes of unsymmetrical tetradentate (OSN2) Schiff base ligands.  

PubMed

Cobalt ion complexes with the Schiff bases, (4-X-2-{[2-(2-pyridine-2-yl-ethylsulfanyl)ethylimino]methyl}phenol (X=methoxy (OMe), phenylazo (N(2)Ph), bromo (Br), nitro (NO(2))),were synthesized and investigated by several techniques using elemental analysis (C, H, N), FTIR, electronic spectra and molar conductivity. The thermal stability of free ligands and related cobalt complexes were studied by using differential scanning calorimetry (DSC) and thermogravimetric analyses (TGA). Cyclic voltammetry indicates that the investigated cobalt complexes, under the experimental conditions, have irreversible redox behavior. The synthesized compounds have antibacterial activity against the four Gram-positive bacteria: Streptococcus pyogenes, Streptococcus agalactiae, Staphylococcus aureus and Bacillus anthracis and also against the two Gram-negative bacteria: Klebsiella pneumoniae and Pseudomonas aeruginosa. The activity data show that the parent Schiff bases are more potent antibacterials than the cobalt complexes. PMID:19608303

Saghatforoush, Lotf Ali; Chalabian, Firoozeh; Aminkhani, Ali; Karimnezhad, Ghasem; Ershad, Sohrab

2009-11-01

273

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

PubMed

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

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

2014-12-10

274

Synthesis, characterization and antimicrobial activity of transition metal complexes with the Schiff base derived from imidazole-2-carboxaldehyde and glycylglycine  

Microsoft Academic Search

The Co(II), Ni(II) and Cu(II) complexes of the Schiff base derived from imidazole-2-carboxaldehyde and glycylglycine were synthesized and characterized by elemental analysis, PMR, molar conductance, IR, electronic, magnetic measurements, ESR, redox properties, thermal studies, XRD and SEM. Conductance measurements indicate that the complexes are 1 : 1 electrolytes. IR data show that the ligand is tetradentate with imidazole nitrogen, azomethine

R. Selwin Joseyphus; M. Sivasankaran Nair

2009-01-01

275

Synthesis, characterization and crystal structures of dinuclear macrocyclic Schiff base copper(I) complexes bearing different bridges  

Microsoft Academic Search

Utilizing a new 20-membered macrocyclic Schiff base ligand with two coordination sites formed from the [2+2] condensation of 1,3-diaminopropane and benzene-1,3-dicarboxaldehyde in the presence of CuX (X=Cl?, Br?, I?) salts, air-stable dicopper(I) complexes were synthesized in acetonitrile, intramolecularly linked via two halide groups, and characterized by different physico-chemical techniques. The single crystal X-ray diffraction technique indicates these complexes consist of

Ali Akbar Khandar; Ray J. Butcher; Marjan Abedi; Seyed Abolfazl Hosseini-Yazdi; Mehmet Akkurt; M. Nawaz Tahir

2010-01-01

276

Metal Complexes of Non-Symmetric Tetradentate Schiff Bases Derived from N-(1-hydroxy-2-acetonaphthone)-1-amino-2-phenyleneimine  

Microsoft Academic Search

Novel non-symmetrical tetradentate Schiff base complexes with N2O2 and N3O donor sites have been obtained using the half-unit N-(l-hydroxy-2-acetonaphthone)-l-amino-2-phenyleneimine (HL). Two reaction pathways have been used (i) preparation of the free ligand which is then reacted with the desired metal salt, and (ii) template synthesis without isolation of the free ligand. The prepared nickel and copper complexes have been characterized

Davar M. Boghaei; Maryam Lashanizadegan

2000-01-01

277

Synthesis, spectroscopy, thermal analysis, magnetic properties and biological activity studies of Cu(II) and Co(II) complexes with Schiff base dye ligands.  

PubMed

Three azo group-containing Schiff base ligands, namely 1-{3-[(3-hydroxypropylimino) methyl]-4-hydroxyphenylazo}-4-nitrobenzene (2a), 1-{3-[(3-hydroxypropylimino) methyl]-4-hydroxyphenylazo}-2-chloro-4-nitrobenzene (2b) and 1-{3-[(3-hydroxypropylimino) methyl]-4-hydroxyphenylazo}-4-chloro-3-nitrobenzene (2c) were prepared. The ligands were characterized by elemental analysis, FTIR spectroscopy, UV-Vis spectroscopy, ¹³C- and ¹H-NMR spectroscopy and thermogravimetric analysis. Next the corresponding copper(II) and cobalt(II) metal complexes were synthesized and characterized by the physicochemical and spectroscopic methods of elemental analysis, FTIR spectroscopy, UV-Vis spectroscopy, magnetic moment measurements, and thermogravimetric analysis (TGA) and (DSC). The room temperature effective magnetic moments of complexes are 1.45, 1.56, 1.62, 2.16, 2.26 and 2.80 B.M. for complexes 3a, 3b, 3c, 4a 4b, and 4c, respectively, indicating that the complexes are paramagnetic with considerable electronic communication between the two metal centers. PMID:22643354

Ahmadi, Raziyeh Arab; Amani, Saeid

2012-01-01

278

Selective anion binding by a cofacial binuclear zinc complex of a Schiff-base pyrrole macrocycle.  

PubMed

The synthesis of the new cofacial binuclear zinc complex [Zn(2)(L)] of a Schiff-base pyrrole macrocycle is reported. It was discovered that the binuclear microenvironment between the two metals of [Zn(2)(L)] is suited for the encapsulation of anions, leading to the formation of [K(THF)(6)][Zn(2)(?-Cl)(L)]·2THF and [Bu(n)(4)N][Zn(2)(?-OH)(L)] which were characterized by X-ray crystallography. Unusually obtuse Zn-X-Zn angles (X = Cl: 150.54(9)° and OH: 157.4(3)°) illustrate the weak character of these interactions and the importance of the cleft preorganization to stabilize the host. In the absence of added anion, aggregation of [Zn(2)(L)] was inferred and investigated by successive dilutions and by the addition of coordinating solvents to [Zn(2)(L)] solutions using NMR spectroscopy as well as isothermal microcalorimetry (ITC). On anion addition, evidence for deaggregation of [Zn(2)(L)], combined with the formation of the 1:1 host-guest complex, was observed by NMR spectroscopy and ITC titrations. Furthermore, [Zn(2)(L)] binds to Cl(-) selectively in THF as deduced from the ITC analyses, while other halides induce only deaggregation. These conclusions were reinforced by density functional theory (DFT) calculations, which indicated that the binding energies of OH(-) and Cl(-) were significantly greater than for the other halides. PMID:21391550

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

2011-04-01

279

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

SciTech Connect

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.

Bozell, J.J.; Hames, B.R. [National Renewable Energy Lab., Golden, CO (United States); Dimmel, D.R. [Institute of Paper Science and Technology, Atlanta, GA (United States)

1995-04-21

280

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

PubMed Central

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

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

2011-01-01

281

Preparation and biodistribution of copper-67 complexes with tetradentate Schiff-base ligands.  

PubMed

Uncharged, lipophilic, low molecular weight copper complexes labeled with generator-produced copper-62 are of interest as potential radiopharmaceutials for imaging the brain with positron emission tomography (PET). We report here the synthesis and biodistribution of a series of [67Cu]copper(II) complexes with tetradentate N2O2(2-)Schiff-base ligands. The compounds studied varied in lipophilicity from log P = 1.7 to log P = 3.6, where P is the octanol/water partition coefficient. In rat biodistribution studies the tracers were generally found to penetrate the blood-brain barrier following intravenous injection, but some far better than others. For closely related compounds brain uptake at 1 min postinjection increased with increasing lipophilicity, although log P was clearly not the sole determinant of high brain uptake. Substantial variations were also observed in the rate at which these various compounds are cleared from brain, with a few exhibiting the prolonged cerebral retention of tracer that would be desired for imaging with 62Cu and PET. PMID:8046620

John, E K; Bott, A J; Green, M A

1994-04-01

282

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

PubMed Central

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).

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

2013-01-01

283

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

SciTech Connect

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.

Singh, Udayshankar G. [Department of Chemistry, Open University, Milton Keynes MK7 6AA (United Kingdom)]. E-mail: usingh@engr.ucsb.edu; Williams, Ruth T. [Department of Chemistry, Open University, Milton Keynes MK7 6AA (United Kingdom)]. E-mail: r.t.williams@open.ac.uk; Hallam, Keith R. [Interface Analysis Centre, University of Bristol, Bristol BS2 8BS (United Kingdom)]. E-mail: k.r.hallam@bristol.ac.uk; Allen, Geoffrey C. [Interface Analysis Centre, University of Bristol, Bristol BS2 8BS (United Kingdom)]. E-mail: g.c.allen@bristol.ac.uk

2005-11-15

284

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

PubMed

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) free radical scavenging and reducing power activity of superoxide anion radical generated non-enzymatic systems. Electrochemical and thermal properties of the compounds were investigated. PMID:21752697

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

2011-10-15

285

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

SciTech Connect

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.

Li Wei; Li Zongwei [Department of Chemistry, Nankai University, 94 Weijing Road, Tianjin 300071 (China); Li Licun [Department of Chemistry, Nankai University, 94 Weijing Road, Tianjin 300071 (China); State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002 (China)], E-mail: llicun@nankai.edu.cn; Liao Daizheng; Jiang Zonghui [Department of Chemistry, Nankai University, 94 Weijing Road, Tianjin 300071 (China)

2007-10-15

286

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

PubMed

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

Mohammadi, Khosro; Rastegari, Mina

2012-11-01

287

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

NASA Astrophysics Data System (ADS)

A series of new VO(IV) complexes with two new tetradentate Schiff base of 4,4'-(2,2-dimethylpropane-1,3-diyl)-bis(azan-1-yl-1-yldene)dipent-2-en-2-ol) [H2L1] and 3,3'-(2,2-dimethylpropane-1,3-diyl)azan-1-yl-1-ylidene)-bis(1-phenylbut-1-en-1-ol) [H2L2] (which have been derived from 2,2-dimethyl-1,3-diaminopropan, and diketones of acetylacetone and benzoylacetone) were synthesized and characterized by 1H NMR, 13C NMR, FT-IR, mass and UV-Vis spectrophotometry. The electrochemical properties of the vanadyl complexes were investigated by means of cyclic voltammetry. The oxidation potentials are increased by increasing the electron-withdrawing properties of functional groups of the Schiff base ligands according to the trend of Me < Ph. The thermogravimetry (TG) and differential thermoanalysis (DTA) of the VO(IV) complexes were carried out in the range of 20-700 °C. The complexes were decomposed in two stages. Also, decomposition of the synthesized complexes is related to the Schiff base characteristics. The thermal decomposition of the studied reactions was first order. The kinetic parameters for the decomposition steps in vanadyl complexes thermograms have been calculated.

Mohammadi, Khosro; Rastegari, Mina

2012-11-01

288

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

NASA Astrophysics Data System (ADS)

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.

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

2014-01-01

289

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

PubMed

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, (1)H NMR, (13)C 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 (13)C 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. PMID:24021948

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

2014-01-01

290

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

PubMed Central

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

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

2011-01-01

291

Facile synthesis of Cu(II) complexes of monocondensed N,N,N donor Schiff base ligands: Crystal structure, spectroscopic and magnetic properties  

Microsoft Academic Search

Four new copper(II) complexes, [(CuL1N3)2](ClO4)2 (1), [(CuL2N3)2](ClO4)2 (2), [CuL3(N3)(ClO4)]n (3) and [CuL4(?-1,1-N3)(?-1,3-N3)(ClO4)]n (4) where L1=N1-pyridin-2-yl-methylene-propane-1,3-diamine, L2=N1-(1-pyridin-2-yl-ethylidene)propane-1,3-diamine, L3=N1-(1-pyridin-2-yl-ethylidene)ethane-1,2-diamine and L4=N1-(1-pyridin-2-yl-ethylidene)propane-1,2-diamine are four tridentate N,N,N donor Schiff base ligands, have been derived and structurally characterized by X-ray crystallography. Compounds 1 and 2 consist of double basal–apical end-on (EO) azide bridged dinuclear CuII complexes with square-pyramidal geometry. In complex 3 the square planar

Shouvik Chattopadhyay; Mau Sinha Ray; Michael G. B. Drew; Albert Figuerola; Carmen Diaz; Ashutosh Ghosh

2006-01-01

292

pH-metric and spectroscopic properties of new 4-hydroxysalicylidene-2-aminopyrimidine Schiff-base transition metal complexes  

Microsoft Academic Search

The new complexes, cis-[WO2(Hsap)2], [Ru(PPh3)2(Hsap)2], [Pd(Hsap)Cl(H2O)], [Pd(PPh3)2(Hsap)]Cl, [Ag(Hsap)(H2O)2], [Ni(Hsap)(AcO)(H2O)2], [Ni(Hsap)2] and [Cu(Hsap)Cl(H2O)] are reported, where H2sap is 4-hydroxysalicylidene-2-amino pyrimidine Schiff-base. The complexes were characterized by elemental analyses, spectroscopic (IR, NMR, UV–vis, ESR and mass) and physical techniques (conductivity, magnetic and thermal measurements). The Schiff-base H2sap behaves as a bidentate chelate with the deprotonated 2-hydroxy and azomethine nitrogen centers with the

Abd El-Fatah Ouf; Mayada S. Ali; Eman M. Saad; Sahar I. Mostafa

2010-01-01

293

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)

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

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

2012-12-01

294

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

PubMed

A new asymmetric heptaaza Schiff base macrocyclic bis(pendant donor) manganese(II) complex, [MnL(1)](ClO(4))(2).CH(3)CN (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. PMID:20637685

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

2010-10-01

295

Synthesis and characterization of molybdenum complexes with bidentate Schiff base ligands within nanoreactors of MCM-41 as epoxidation catalysts  

Microsoft Academic Search

The mesoporous molecular sieve MCM-41 was covalently grafted with 3-aminopropyl trimethoxysilane to give aminopropyl modified MCM-41 (AmpMCM-41). Reaction of this material with furfural, pyrrolcarbaldehyde, 2-acetylpyrrol, 2-aminoacetophenone, salicylaldehyde and acetylacetone afforded the corresponding supported Schiff base ligands. Subsequent reaction with bis(acetylacetonato)dioxomolybdenum(VI) leads to various molybdenum complexes supported on MCM-41 through propyl chain spacer. Characterization of these materials was carried out with

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

2006-01-01

296

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

Microsoft Academic Search

Metal complexes are synthesized with Schiff bases derived from o-phthalaldehyde (opa) and amino acids viz., glycine (gly) l-alanine (ala), l-phenylalanine (pal). Metal ions coordinate in a tetradentate or hexadentate manner with these N2O2 donor ligands, which are characterized by elemental analysis, molar conductance, magnetic moments, IR, electronic, 1H NMR and EPR spectral studies. The elemental analysis suggests the stoichiometry to

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

2008-01-01

297

Synthesis and Characterization of Mononuclear Copper(II), Cobalt(II) and Nickel(II) Chelates with New Bidentate Aromatic Schiff Bases  

Microsoft Academic Search

Copper(II), cobalt(II) and nickel(II) complexes of ligands such as N-(3-hydroxy salicylidene)-3, 5-di(tert-butyl)-4-hydroxyaniline (L H) and N-(3, 4-dihydroxysalicylidene)-3, 5-di(tert-butyl)-4-hydroxyaniline (LH) have been prepared and characterized by elemental analyses, magnetic moment, infrared, electronic absorption spectral data and molar conductance. Thermal decomposition studies show that the copper, cobalt and nickel complexes decompose with the loss of hydrated water followed by loss of the

Mehmet Tümer; Hüseyin Köksal; Selahattin Serin

1997-01-01

298

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

PubMed

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

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

2014-02-01

299

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.  

PubMed

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, (1)H 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(2)(1a-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. PMID:20363662

Raman, N; Selvan, A; Manisankar, P

2010-07-01

300

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)

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.

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

2010-07-01

301

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

Microsoft Academic Search

The Schiff-base complex ion formed between the vitamin B6 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

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

2007-01-01

302

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

Microsoft Academic Search

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

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

2007-01-01

303

Oxorhenium(V) complexes containing tridentate Schiff-base and monothiol coligands  

PubMed Central

The reaction of [n-(C4H9)4N][ReOBr4(OPPh3)] with the tridentate Schiff-base [HOC6H4C(H)NC6H4SH] allows for the isolation of [ReOBr{?3-(OC6H4C(H)NC6H4S)}] (1). The reaction of [n-(C4H9)4N][ReOBr4(OPPh3)] with [HOC6H4C(H)NC6H4SH] and the appropriate benzenethiol (C6H4X-4-SH) where X=H, Br, Cl, F, and OCH3 in methanol–acetonitrile treated with triethylamine has led to the isolation of a series of rhenium complexes of the type [ReO{?3-(OC6H4C(H)NC6H4S)} (?1-C6H4X-4-S)] (X=H (2), Br (3), Cl (4), F (5), and OCH3 (6)). Likewise, under similar reaction conditions, the use of benzylmercaptan ligands of the type (C6H4X-4-CH2SH) where X=H, Cl, F, and OCH3 has led to the isolation of a series of rhenium complexes of the type [ReO{?3-(OC6H4C(H)NC6H4S)} (?1-C6H4X-4-CH2S)] (X=H (7), Cl (8), F (9), and OCH3 (10)). The incorporation of the appropriate amine functionality into the substituent R of the monodentate ligand allows for the isolation of a cationic oxorhenium(V) species, namely, [ReO{?3-(OC6H4C(H)NC6H4S)} (?1-C5H4NH-2-S)][Br] (11).

Femia, Frank J.; Chen, Xiaoyuan; Babich, John W.; Zubieta, Jon

2010-01-01

304

Studies on Biologically Active Complexes of Nickel(II), Copper(II) and Zinc(II) with Tridentate NNO, NNS and NNN Donor Pyrazine Derived Ligands  

Microsoft Academic Search

New biologically active tridentate pyrazine-derived NNO, NNS and NNN Schiff base ligands (I, II and III) and their nickel(II), copper(II) and zinc(II) complexes 1–9. have been synthesised and characterised on the basis of conductance and magnetic measurements, elemental analyses, and H-NMR, IR and electronic-spectral data. The synthesised ligands and their complexes have been evaluated for antibacterial activity against Esoherichi a

Zahid Hussain Chohan; Humayun Pervez

1993-01-01

305

DFT Studies on second-order nonlinear optical properties of mono (salicylaldiminato) Nickel(II) polyenyl Schiff base metal complexes  

NASA Astrophysics Data System (ADS)

Density function theory (DFT) B3LYP/6-31g(d)-finite field (FF) method was employed to investigate the second-order nonlinear optical (NLO) properties of Nickel(II) polyenyl Schiff base complexes and its polyenyl ligands. It is found that the complexes display higher second-order NLO responses than their ligands. An enhancement of second-order NLO properties of complexes because the Ni 2+ ion increased the electron densities distribution of coordinated atoms and adjacent carbon atoms in frontier molecular orbitals, and reduced the gaps between occupied and unoccupied orbitals. Thus the metal complexes display better second-order NLO responses.

Liu, Chun-Guang; Qiu, Yong-Qing; Sun, Shi-Ling; Li, Na; Yang, Guo-Chun; Su, Zhong-Min

2007-07-01

306

Synthesis and electrochemical studies of heterobinuclear complexes containing copper and molybdenum nitrosyl groups linked by Schiff base ligands  

Microsoft Academic Search

The reaction of [MoCl(NO)Tp\\u000a * = tris(3,5-dimethylpyrazolylborate] with copper Schiff base complexes derived by condensation of one mole each of 2,5-dihydroxybenzaldehyde\\u000a and salicylaldehyde with ?,? diamines [NH2(CH2)\\u000a n\\u000a NH2, n = 2–4] yields heterobinuclear complexes with two potential redox centres. I.r., electronic and e.s.r. spectroscopic properties\\u000a of these complexes are described. Cyclic voltammetric data of the base complexes in DMSO

Samwel T. Lutta

2000-01-01

307

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

Microsoft Academic Search

A tetradentate N2O2 donor Schiff base ligand, H2L, 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

Magdy Shebl

2008-01-01

308

Structurally Diverse Copper Complexes Bearing NNO-Tridentate Schiff-Base Derivatives as Efficient Catalysts for Copolymerization of Carbon Dioxide and Cyclohexene Oxide.  

PubMed

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

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

2014-05-19

309

NH-type of chiral Ni(II) complexes of glycine Schiff base: design, structural evaluation, reactivity and synthetic applications.  

PubMed

The work being reported here deals with the design of a new type of "N-H" Ni(II) complexes of glycine Schiff bases and study general aspects of their reactivity. It was confirmed that the presence of NH function in these Ni(II) complexes does not interfere with the homologation of the glycine residue, rendering these derivatives of high synthetic value for the general synthesis of ?-amino acids. In particular, the practical application of these NH-type complexes was demonstrated by asymmetric synthesis of various ?-substituted pyroglutamic acids via Michael addition reactions with chiral Michael acceptors. PMID:24424805

Bergagnini, Mackenzie; Fukushi, Kazunobu; Han, Jianlin; Shibata, Norio; Roussel, Christian; Ellis, Trevor K; Aceña, José Luis; Soloshonok, Vadim A

2014-02-28

310

Synthesis, crystal structures and electronic properties of Schiff base nickel (II) complexes: Towards solvatochromism induced by a photochromic solute  

Microsoft Academic Search

Two new mononuclear nickel (II) complexes incorporating Schiff base ligands, bis(N-R-1-phenylethyl- or N-2-propyl-3,5-dichlorosalicydenaminato)nickel (II), have been synthesized and characterized. The former chiral brown paramagnetic complex adopts a compressed tetrahedral [NiN2O2] coordination geometry of ?(R,R) absolute configuration with the coordination bond angles of N–Ni–N=116.3(2)° and O–Ni–O=141.4(2)°. On the other hand, the latter green diamagnetic complex adopts a square planar trans-[NiN2O2] coordination

Takashiro Akitsu; Yasuaki Einaga

2005-01-01

311

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

Microsoft Academic Search

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

Yuhua Fan; Caifeng Bi; Jinying Li

2003-01-01

312

Complexes of a porphyrin-like N4-donor Schiff-base macrocycle.  

PubMed

A metal-free 16-membered N4-donor [1 + 1] Schiff-base macrocycle was isolated as HL(Pr)·2acid, by 1?:?1 condensation of diphenylamine-2,2'-dicarboxaldehyde (1), dipropylene triamine and an excess of either acetic or formic acid, or as HL(Pr)·(tosylic acid) when just one equivalent of tosylic acid was employed. Interestingly, the acid-free synthesis employed for the 14-membered analogue HL(Et) failed to generate pure HL(Pr) macrocycle, but nevertheless the crude product obtained was able to be used in subsequent complexation reactions to form five mononuclear complexes: Zn(II)L(Pr)(BF4)·H2O·0.5IPA (where IPA is isopropylalcohol), [Cu(II)L(Pr)](BF4), [Ni(II)L(Pr)](BF4), [Co(II)L(Pr)](BF4)·0.5H2O, [Fe(III)L(Pr)(NCS)2]·1.5H2O. Crystal structure determinations show that, like the HL(Et) analogues, [Ni(II)L(Pr)](BF4) features a square planar N4 coordinated Ni(II) centre and [Fe(III)L(Pr)(NCS)2]·0.15MeOH·0.2H2O features an octahedral N6 coordinated Fe(III) centre (two NCS anions bound axially). In both cases the N4-donor macrocycle is bound equatorially to the metal ion. Cyclic voltammograms of the BF4 complexes were carried out in MeCN vs. 0.01 mol L(-1) AgNO3/Ag and revealed multiple redox processes. The Zn(II) complex exhibits multiple ligand-centered redox processes. Interestingly, [Ni(II)L(Pr)](BF4) has two reversible redox processes, at E(m) = +0.38 (?E = 0.06 V) and -1.7 V (?E = 0.06 V), whereas the previously reported analogue [Ni(II)L(Et)](BF4) had a process at E(pc) = +0.59 V with only a weak return wave. Likewise, [Cu(II)L(Pr)](BF4) has a reversible process, at E(m) = -1.17 V (?E = 0.06 V) plus a process at E(pc) = +0.45 V, whereas previously reported [Cu(II)L(Et)](BF4) only featured irreversible processes, with the oxidation occurring at E(pc) = +0.50 V. PMID:23400271

Wilson, Rajni K; Brooker, Sally

2013-06-14

313

Photocytotoxicity and near-IR light DNA cleavage activity of oxovanadium(IV) Schiff base complexes having phenanthroline bases  

Microsoft Academic Search

Oxovanadium(IV) complexes [VO(L)(B)] (1–3), where H2L is a Schiff base ligand 2-(2-hydroxybenzylideneamino)phenol and B is 1,10-phenanthroline (phen for 1), dipyrido[3,2-d:2?,3?-f]quinoxaline (dpq for 2) or dipyrido[3,2-a:2?,3?-c]phenazine (dppz for 3), have been prepared, characterized and their DNA binding property and photo-induced DNA cleavage activity studied. Complex 3 which is structurally characterized by X-ray crystallography shows the presence of an oxovanadium(IV) moiety in

Puja Prasad; Pijus K. Sasmal; Ritankar Majumdar; Rajan R. Dighe; Akhil R. Chakravarty

2010-01-01

314

Triiodide-selective polymeric membrane electrodes based on Schiff base complexes of Cu (II) and Fe (III)  

Microsoft Academic Search

Poly(vinyl chloride) (PVC) membrane electrodes based on two complexes of Schiff base 2,2?[4,4?-diphenylmethane bis (nitromethylidyne)] bisphenol, L, with copper (II) and iron (III) ions were prepared, characterized and used for determination of triiodide ions. The electrodes based on CuL and FeL complexes show an anionic response slope of ?60mV per decade in a linear activity range 6.0×10?1 to 8.0×10?6moll?1 and

Susan Sadeghi; Abolfazl Gafarzadeh; Mohammed Ali Naseri; Hashem Sharghi

2004-01-01

315

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

Microsoft Academic Search

Metal complexes of a novel Schiff base (HL=3-(4?-ethylazomethinobenzene sulphonamide)-4-methoxy-1,2,5-thiadiazole) derived from condensation of sulphametrole and varelaldehyde are reported and characterized based on elemental analyses, IR, solid reflectance, magnetic moment, molar conductance, and thermal analysis (TG). From the elemental analyses data, 1:1 metal complexes are formed having the general formulae [MCl3(HL)(H2O)]·3H2O (M=Cr(III), Fe(III)) and [MCl2(HL)(H2O)2]·yH2O (where M=Mn(II), Fe(II), Co(II), Ni(II), Cu(II)

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

2010-01-01

316

Synthesis, characterization and crystal structures of di-three-coordinated copper(I) macrocyclic Schiff base complexes  

Microsoft Academic Search

The air-stable di-copper(I) complexes Cu2L(SCN)2 (1) and Cu2L(SCN)1.86I0.14 (2) of the N4 macrocyclic Schiff base ligand L have been synthesized and characterized by IR, elemental analysis, UV–Vis and crystal structure determination. X-ray analysis of the complexes shows an approximate distorted trigonal planar geometry around each copper(I) ion that is constructed from one N-bonded thiocyanate (or iodide in 2) group and

Ali Akbar Khandar; Ray J. Butcher; Marjan Abedi; Seyed Abolfazl Hosseini-Yazdi; Mehmet Akkurt; M. Nawaz Tahir

2011-01-01

317

Synthesis and spectral characterization of homo-and hetero-dinuclear complexes with a new septadentate Schiff base ligand  

Microsoft Academic Search

Reaction between 3-formylsalicylic acid and bis-(2-aminophenyl)-disulphide yields a septadentate Schiff base with N2SO4 donor frame of which the inner compartment is N2SO2 and the outer is O2O2 type. It forms several complexes with inner copper centre and outer nontransition\\/transition metal ions. The complexes have\\u000a been characterised by elemental analyses, spectral (IR, absorption, diffused reflectance), thermal and magnetic data. Dinuclear\\u000a copper

J K Nag; D Das; S Pal; C Sinha

2001-01-01

318

Synthesis, structure, DNA binding and cleavage properties of ternary amino acid Schiff base-phen\\/bipy Cu(II) complexes  

Microsoft Academic Search

Ternary Cu(II) complexes [Cu(II)(saltrp)(B)] (1,2), (saltrp=salicylidene tryptophan, B=1,10 phenathroline (1) or 2,2? bipyridine (2)) were synthesized and characterized. Complex 2 was structurally characterized by single crystal X-ray crystallography. The molecular structure shows a distorted square pyramidal coordination geometry (CuN3O2) in which the ONO donor Schiff base is bonded to the Cu(II) in the basal plane. The N,N donor heterocyclic base

Pulimamidi Rabindra Reddy; Addla Shilpa; Nomula Raju; Pallepogu Raghavaiah

2011-01-01

319

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

PubMed

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

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

2014-12-10

320

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

PubMed

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 ?8-?8 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. PMID:24437575

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

2014-02-11

321

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

NASA Astrophysics Data System (ADS)

Complexes of copper(II) and nickel(II) of general composition M(L)2X2, have been synthesized [where L = 3-Bromoacetophenone thiosemicarbazone and X = CH3COO-, Cl- and NO3-]. All the complexes were characterized by elemental analysis, magnetic moments, IR, electronic and EPR spectral studies. The ligand behaved as bidentate and coordinated through sulfur of sbnd Cdbnd S group and nitrogen atoms of sbnd Cdbnd N group. The copper(II) and nickel(II) complexes were found to have magnetic moments 1.94-2.02 BM, 2.96-3.02 BM respectively which was corresponding to one and two unpaired electrons respectively. The molar conductance of the complexes in solution of DMSO lies in the range of 10-20 ?-1 cm2 mol-1 indicating their non-electrolytic behavior. On the basis of EPR, electronic and infrared spectral studies, tetragonal geometry has been assigned for copper(II) complexes and an octahedral geometry for nickel(II) complexes. The values of Nephelauxetic parameter ? lie in the range 0.19-0.37 which indicated the covalent character in metal ligand '?' bond. Synthesized ligand and its copper(II) and nickel(II) complexes have also been screened against different bacterial and fungal species which suggested that complexes are more active than the ligands in antimicrobial activities.

Chandra, Sulekh; Bargujar, Savita; Nirwal, Rita; Qanungo, Kushal; Sharma, Saroj K.

2013-09-01

322

Oxo-molybdenum and oxo-tungsten complexes of Schiff bases relevant to molybdoenzymes.  

PubMed

A series of octahedral dioxomolybdenum(VI) complexes of the type [MoO(2)L(2)] {L = 4-Ar-pent-2-en-ol; L(i-Pr2Ph) with Ar = 2,6-diisopropylphenyl (1); L(Me2Ph) with Ar = 2,6-dimethylphenyl (2), L(MePh) with Ar = 2-methylphenyl (3) and with Ar = phenyl (4)} and dioxotungsten(VI) compounds [WO(2)L(2)] {L(i-Pr2Ph) (5); L(Me2Ph) (6) and L(MePh) (7)} with Schiff bases have been synthesized as models for oxotransferases. Spectroscopic characterization in solution shows with the sterically encumbered ligands L(i-Pr2)Ph and L(Me2)Ph isomerically pure products whereas the ligand with only one substituent in ortho position at the aromatic ring L(MePh) revealed a dynamic mixture of three isomers as confirmed by variable temperature NMR spectroscopy. Single crystal X-ray diffraction analyses of compounds 1, 2, and 4 and showed them to be in the N,N-trans conformation consistent with the larger steric demand at nitrogen. Oxygen atom transfer (OAT) properties towards trimethylphosphine were investigated leading to the isolation of two mononuclear molybdenum(IV) compounds [MoO(PMe(3))(L(Me2Ph))(2)] (8) and [MoO(PMe(3))(L(MePh))(2)] (9) as confirmed by spectroscopic and crystallographic means. The kinetics of OAT between complex [MoO(2)(L(Me2Ph))(2)] (2) and PMe(3) was investigated by UV/Vis spectroscopy under pseudo-first-order conditions revealing single-step reactions with Eyring values of DeltaH(double dagger) = +60.79 kJ mol(-1) and DeltaS(double dagger) = -112 J mol(-1) K(-1) and a first-order dependence of phosphine consistent with a slow nucleophilic attack of the phosphine showing the octahedral geometries of this system to be unfavorable for OAT. Compound 1 showed no OAT reactivity towards PMe(3) emphasizing the influence of sterical properties. Furthermore, the reactivity of the reduced compounds [MoO(PMe(3))(L(Me2Ph))(2)] (8) and [MoO(PMe(3))(L(MePh))(2)] (9) towards molecular oxygen was investigated leading, in the case of 8, to the substitution of PMe(3) by O(2) under formation of the peroxo compound [MoO(O(2))(L(Me2Ph))(2)] (10). In contrast, the analogous reaction employing 9 led to oxidation forming the dioxo compound [MoO(2)(L(MePh))(2)] (3). PMID:20449078

Lyashenko, Ganna; Saischek, Gerald; Judmaier, Martina E; Volpe, Manuel; Baumgartner, Judith; Belaj, Ferdinand; Jancik, Vojtech; Herbst-Irmer, Regine; Mösch-Zanetti, Nadia C

2009-08-01

323

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

NASA Astrophysics Data System (ADS)

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

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

2013-05-01

324

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

NASA Astrophysics Data System (ADS)

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.

Chellaian, Justin Dhanaraj; Johnson, Jijo

2014-06-01

325

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

PubMed

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, (1)H 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. PMID:24637276

Chellaian, Justin Dhanaraj; Johnson, Jijo

2014-06-01

326

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

NASA Astrophysics Data System (ADS)

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.

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

2014-05-01

327

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

PubMed

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

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

2011-04-01

328

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

PubMed Central

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.

Abdulghani, Ahlam Jameel; Khaleel, Asmaa Mohammed Noori

2013-01-01

329

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

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.

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

1995-04-12

330

A theoretical investigation into the luminescent properties of d8-transition-metal complexes with tetradentate Schiff base ligands.  

PubMed

A theoretical investigation on the luminescence efficiency of a series of d(8) transition-metal Schiff base complexes was undertaken. The aim was to understand the different photophysics of [M-salen](n) complexes (salen = N,N'-bis(salicylidene)ethylenediamine; M = Pt, Pd (n = 0); Au (n = +1)) in acetonitrile solutions at room temperature: [Pt-salen] is phosphorescent and [Au-salen](+) is fluorescent, but [Pd-salen] is nonemissive. Based on the calculation results, it was proposed that incorporation of electron-withdrawing groups at the 4-position of the Schiff base ligand should widen the (3)MLCT-(3)MC gap (MLCT = metal-to-ligand charge transfer and MC = metal centered, that is, the dd excited state); thus permitting phosphorescence of the corresponding Pd(II) Schiff base complex. Although it is experimentally proven that [Pd-salph-4E] (salph = N,N'-bis(salicylidene)-1,2-phenylenediamine; 4E means an electron-withdrawing substituent at the 4-position of the salicylidene) displays triplet emission, its quantum yield is low at room temperature. The corresponding Pt(II) Schiff base complex, [Pt-salph-4E], is also much less emissive than the unsubstituted analogue, [Pt-salph]. Thus, a detailed theoretical analysis of how the substituent and central metal affected the photophysics of [M-salph-X] (X is a substituent on the salph ligand, M = Pt or Pd) was performed. Temperature effects were also investigated. The simple energy gap law underestimated the nonradiative decay rates and was insufficient to account for the temperature dependence of the nonradiative decay rates of the complexes studied herein. On the other hand, the present analysis demonstrates that inclusions of low-frequency modes and the associated frequency shifts are decisive in providing better quantitative estimates of the nonradiative decay rates and the experimentally observed temperature effects. Moreover, spin-orbit coupling, which is often considered only in the context of radiative decay rate, has a significant role in determining the nonradiative rate as well. PMID:24715418

Tong, Glenna So Ming; Chow, Pui Keong; To, Wai-Pong; Kwok, Wai-Ming; Che, Chi-Ming

2014-05-19

331

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

PubMed

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

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

2014-10-15

332

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

PubMed

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

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

2014-01-24

333

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

NASA Astrophysics Data System (ADS)

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.

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

2014-10-01

334

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

PubMed

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*, ?H*, ?S* and ?G* are calculated from the DTG curves using Coats-Redfern method. The synthesized ligand, in comparison to their metal complexes also was screened for its antibacterial activity against bacterial species, Escherichia coli, Pseudomonas aeruginosa, Staphylococcus pyogones and Fungi (Candida). The activity data shows that the metal complexes to be more potent/antibacterial than the parent Schiff base ligand against one or more bacterial species. PMID:21130026

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

2011-01-01

335

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

Microsoft Academic Search

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

K. C. Raju; P. K. Radhakrishnan

2003-01-01

336

Schiff base oxovanadium(IV) complexes of phenanthroline bases showing DNA photocleavage activity at near-IR light and photocytotoxicity  

Microsoft Academic Search

Oxovanadium(IV) complexes [VO(L)(B)](ClO4) (1–3) of N-2-pyridylmethylidine-2-hydroxyphenylamine (HL) Schiff base and phenanthroline bases (B), viz. 1,10-phenanthroline (phen in 1), dipyrido[3,2-d:2?,3?-f]quinoxaline (dpq in 2) or dipyrido[3,2-a:2?,3?-c]phenazine (dppz in 3), were prepared, characterized and their DNA binding property, photo-induced DNA cleavage activity and photocytotoxicity in HeLa cells studied. The crystal structure of 1 shows the presence of a VO2+ moiety in VO2N4 coordination

Puja Prasad; Pijus K. Sasmal; Imran Khan; Paturu Kondaiah; Akhil R. Chakravarty

2011-01-01

337

PVC-based Cu (II)-Schiff base complex membrane coated graphite electrode for the determination of the triiodide ion  

Microsoft Academic Search

A triiodide-selective electrode based on copper (II)-Schiff base complex as a membrane carrier is proposed. The electrode\\u000a was prepared by incorporating the carrier into a plasticized polyvinylchloride (PVC) membrane and was directly coated on the\\u000a surface of a graphite electrode. The obtained electrode showed a near Nernstian slope of 57.0 ± 0.4 mV\\/decade to I\\u000a 3\\u000a ?\\u000a ions over an

S. Sadeghi; A. Gafarzadeh; H. Naeimi

2006-01-01

338

Synthesis and characterization of tetradentate bis-Schiff base complexes of di- and tri-valent transition metals  

Microsoft Academic Search

The bis-Schiff bases of N2O2 dibasic ligands, H2La and H2Lb are synthesized by the condensation of ethylenediamine (a) and trimethylenediamine (b) with 6-formyl-7-hydroxy-5-methoxy-2-methylbenzo-pyran-4-one. The ligands are characterized using elemental analysis, IR, UV–Vis, H-NMR and mass spectroscopy. The ionization constant pKa values are determined spectrophotometrically. The H-NMR spectra of the ligands show the presence of phenolic coordinating groups. New complexes of

Aida L. El-Ansary; Hussein M. Abdel-Fattah; Nora S. Abdel-Kader

2008-01-01

339

A new Co(II) complex with N,O-donor Schiff base: Synthesis, structure and characterization  

Microsoft Academic Search

A new Co(II) complex with tridentate Schiff base ligand with a N,N,O donor set has been synthesized and characterized by single\\u000a X-ray technique and spectroscopic techniques. The thermochemical properties have been studied. X-ray structure analysis of\\u000a the title compound Co(II)L2 [HL = 2-methyl-6-(2?-hydroxybenzylideneamino) pyridine] shows that the polyhedron around Co(II) is a distorted tetrahedron,\\u000a and the self-assembly via intermolecular ?-?

L. Xu; Yu. V. Mironov; X. Qi; S.-J. Kim

2006-01-01

340

Dissociation constants of some Schiff bases and stability constants of their copper, cobalt, nickel and zinc complexes  

Microsoft Academic Search

The stoichiometry and stability constant of metal complexes with 4-(3-methoxy-salicylideneamino)-5-hydroxynaphthalene-2,7-disulfonic\\u000a acid monosodium salt (H2L) and 4-(3-methoxysalicylideneamino)-5-hydroxy-6-(2,5-dichlorophenylazo)-2,7-naphthalene disulfonic acid monosodium salt\\u000a (H2L1) were studied by potentiometric titration. The stability constants of H2L and H2L1 Schiff bases have been investigated by potentiometric titration and u.v.–vis spectroscopy in aqueous media. The dissociation\\u000a constants of the ligand and the stability constants of the metal

Mehmet Tunçel; Hayati Sar?

2007-01-01

341

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)

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.

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

2011-09-01

342

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

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.

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

2007-01-01

343

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

PubMed Central

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

Company, Anna; Gomez, Laura; Mas-Balleste, Ruben; Korendovych, Ivan V.; Ribas, Xavi; Poater, Albert; Parella, Teodor; Fontrodona, Xavier; Benet-Buchholz, Jordi; Sola, Miquel; Que, Lawrence; Rybak-Akimova, Elena; Costas, Miquel

2008-01-01

344

Fast O2 binding at dicopper complexes containing Schiff-base dinucleating ligands.  

PubMed

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)2C6H3}4]-), where RL is a Schiff-base ligand containing two tridentate binding sites linked by a xylyl spacer, has been prepared and characterized, and its reaction with O2 has been 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 the solid state 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. 1-3BArF and 1-3CF3SO3 in acetone react rapidly with O2 to generate metaestable [CuIII2(mu-O)2(RL)]2+ 1-3(O2) and [CuIII2(mu-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(mu-O)2 form with respect to the CuII2(mu-eta2:eta2-O2) isomer. The reaction of 1X, X = CF3SO3 and BArF, with O2 in acetone has been studied by stopped-flow UV-vis exhibiting an unexpected very fast reaction rate (k=3.82(4)x10(3) M-1 s-1, DeltaH=4.9+/-0.5 kJ.mol-1, DeltaS=-148+/-5 J.K-1.mol-1), nearly 3 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) are discussed and compared with those associated with selected examples of reported models of O2-processing copper proteins. A synergistic role of the copper ions in O2 binding and activation is clearly established from this analysis. PMID:17500512

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 V; Costas, Miquel

2007-06-11

345

pH-metric and spectroscopic properties of new 4-hydroxysalicylidene-2-aminopyrimidine Schiff-base transition metal complexes  

NASA Astrophysics Data System (ADS)

The new complexes, cis-[WO 2(Hsap) 2], [Ru(PPh 3) 2(Hsap) 2], [Pd(Hsap)Cl(H 2O)], [Pd(PPh 3) 2(Hsap)]Cl, [Ag(Hsap)(H 2O) 2], [Ni(Hsap)(AcO)(H 2O) 2], [Ni(Hsap) 2] and [Cu(Hsap)Cl(H 2O)] are reported, where H 2sap is 4-hydroxysalicylidene-2-amino pyrimidine Schiff-base. The complexes were characterized by elemental analyses, spectroscopic (IR, NMR, UV-vis, ESR and mass) and physical techniques (conductivity, magnetic and thermal measurements). The Schiff-base H 2sap behaves as a bidentate chelate with the deprotonated 2-hydroxy and azomethine nitrogen centers with the pendant pyrimidine cyclic nitrogen functionality playing no role in coordination. The dissociation constants of H 2sap and the stability constants of the metal complexes have been determined pH-metrically at various temperatures, and the thermodynamic activation parameters (? S*, ? G*, ? H*) calculated.

Ouf, Abd El-Fatah; Ali, Mayada S.; Saad, Eman M.; Mostafa, Sahar I.

346

Structural and electrochemical studies of Co(II), Ni(II), Cu(II) and Cd(II) complexes with a new symmetrical N 2O 2 Schiff base: Crystal structure of the ligand 1,2-di[4-(2-imino 4-oxo pentane)phenyl]ethane  

Microsoft Academic Search

The crystal structure of a new Schiff base: 1,2-di[4-(2-imino 4-oxo pentane)phenyl]ethane (H2L) is described. This molecule undergoes tautomerism with three tautomers: keto-imine, enol-imine and keto-amine. It acts mainly as a tetradentate ligand. Its complexes with cobalt(II), nickel(II), copper(II) are characterised using spectroscopic determinations and cyclic voltammetry. These new complex species are formulated as [CoL]·(H2O)3, [(NiCl2)2(H2L)], [CuCl2(H2L)] and [CdCl2(H2L)], respectively. The

Amel Ghames; Tahar Douadi; Djahida Haffar; Salah Chafaa; Magali Allain; Mustayeen A. Khan; Gilles M. Bouet

2006-01-01

347

Synthesis, crystal structure and luminescent properties of some Zn(II) Schiff base complexes: experimental and computational study.  

PubMed

A series of Zn(II)-Schiff bases I, II and III complexes were synthesized by reaction of o-phenylenediamine with 3-methylsalicylaldehyde, 4-methylsalicylaldehyde and 5-methylsalicylaldehyde. These complexes were characterized using FT-IR, UV-Vis, Diffuse reflectance UV-Vis, elemental analysis and conductivity. Complex III was characterized by XRD single crystal, which crystallizes in the triclinic system, space group P-1, with lattice parameters a=9.5444(2) Å, b=11.9407(2) Å, c=21.1732(3) Å, V=2390.24(7) Å(3), D ( c )=1.408 Mg m(-3), Z=4, F(000)=1050, GOF=0.981, R1=0.0502, wR2=0.1205. Luminescence property of these complexes was investigated in DMF solution and in the solid state. Computational study of the electronic properties of complex III showed good agreement with the experimental data. PMID:21222144

Eltayeb, Naser Eltaher; Teoh, Siang Guan; Adnan, Rohana; Teh, Jeannie Bee-Jan; Fun, Hoong-Kun

2011-07-01

348

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

NASA Astrophysics Data System (ADS)

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.

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

349

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

PubMed

Metal complexes are synthesized with Schiff bases derived from o-phthalaldehyde (opa) and amino acids viz., glycine (gly) l-alanine (ala), l-phenylalanine (pal). Metal ions coordinate in a tetradentate or hexadentate manner with these N(2)O(2) donor ligands, which are characterized by elemental analysis, molar conductance, magnetic moments, IR, electronic, (1)H NMR and EPR spectral studies. The elemental analysis suggests the stoichiometry to be 1:1 (metal:ligand). Based on EPR studies, spin-Hamiltonian and bonding parameters have been calculated. The g-values calculated for copper complexes at 300K and in frozen DMSO (77K) indicate the presence of the unpaired electron in the dx2-y2 orbital. The evaluated metal-ligand bonding parameters showed strong in-plane sigma- and pi-bonding. X-ray diffraction (XRD) and scanning electron micrography (SEM) analysis provide the crystalline nature and the morphology of the metal complexes. The cyclic voltammograms of the Cu(II)/Mn(II)/VO(II) complexes investigated in DMSO solution exhibit metal centered electroactivity in the potential range -1.5 to +1.5V. The electrochemical data obtained for Cu(II) complexes explains the change of structural arrangement of the ligand around Cu(II) ions. The biological activity of the complexes has been tested on eight bacteria and three fungi. Cu(II) and Ni(II) complexes show an increased activity in comparison to the controls. The metal complexes of opapal Schiff base were evaluated for their DNA cleaving activities with calf-thymus DNA (CT DNA) under aerobic conditions. Cu(II) and VO(II) complexes show more pronounced activity in presence of the oxidant. PMID:18656419

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

2008-12-15

350

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

NASA Astrophysics Data System (ADS)

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

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

2004-09-01

351

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

NASA Astrophysics Data System (ADS)

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

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

352

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

PubMed

Four new complexes, [M(Salpyr)] where Salpyr=N,N'-bis(Salicylidene)-2,3- and 3,4-diiminopyridine and M=Co, Cu, Mn, Ni and Zn were synthesized and characterized by (1)H NMR, IR spectroscopy, elemental analysis and UV-vis spectrophotometry. UV-vis spectrophotometric study of the adduct formation of the zinc(II) complexes, [Zn(2,3-Salpyr)] and [Zn(3,4-Salpyr)], as donor with R(2)SnCl(2) (R=methyl, phenyl, n-butyl), PhSnCl(3) and Bu(3)SnCl as acceptors has been investigated in methanol, as solvent. The formation constants and the thermodynamic free energies were measured using UV-vis spectrophotometry. Titration of the organotin chlorides with Zn(II) complexes at various temperatures (T=283-313K) leads to 1:1 adduct formation. The results show that the formation constants were decreased by increasing the temperature. The trend of the reaction of R(n)SnCl(4-n) as acceptors toward given zinc complexes was as follows: PhSnCl3 > Me2SnCl2 > Ph2SnCl2 > Bu2SnCl2 > Bu3SnCl. By considering the formation constants and the ?G° of the complex formation for the Schiff base as donor and the M(II) as acceptor, the following conclusion was drawn: the formation constant for a given Schiff base changes according to the following trend: Ni > Cu > Co > Zn > Mn. PMID:22626922

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

2012-08-01

353

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

PubMed

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. PMID:24681321

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

2014-07-15

354

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)

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.

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

2014-07-01

355

Structural models for the reduced form of vanadate-dependent peroxidases: vanadyl complexes with bidentate chiral Schiff base ligands.  

PubMed

The penta-coordinated vanadyl complexes [VO(ON)(2)] have been obtained by reaction between [VOX(2)] (X = acetylacetonate or chloride) and the Schiff base ligands HON = (R)-sal-am, (R)-Clsal-am and (S)-naph-am, where sal and naph are the salicylidene and naphthalidene moieties, and am derives from phenylethylamine. The three complexes and the ligand (R)-Clsal-am have been structurally characterized. The geometry of the complexes is in-between trigonal-bipyramidal (with the two imine functions in the axis) and square-pyramidal; tau values range from 0.66 to 0.44. Structural and EPR (electron paramagnetic resonance) features are in accord with the coordination environment proposed for the inactive, reduced (V(IV)) form of the bromoperoxidase from the marine brown alga Ascophyllum nodosum. PMID:15134921

Santoni, Gabriella; Rehder, Dieter

2004-05-01

356

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

NASA Astrophysics Data System (ADS)

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.

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

2014-12-01

357

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

PubMed

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

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

2014-12-10

358

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

Microsoft Academic Search

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

Adel A. A. Emara

1999-01-01

359

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

Microsoft Academic Search

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

Nur?en Sarì; Perihan Gürkan

2003-01-01

360

Synthesis and characterization of polystyrene-anchored monobasic bidentate Schiff base and its complexes with bi-, tri-, tetra- and hexavalent metal ions  

Microsoft Academic Search

A new monobasic bidentate ON donor Schiff base PS–LH2 (where PS–LH2 = polystyrene-anchored Schiff base obtained by condensation of chloromethylated polystyrene (containing 1.17 mmol of chlorine per gram of resin cross-linked with 2% divinylbenzene), 2-hydroxy-1-naphaldehyde and 4-aminosalicylic acid has been synthesized. PS–LH2 reacts with metal complexes to form polystyrene-anchored complexes: PS–LHM(CH3Coo) · DMF (where M = Cu, Zn, Cd, UO2),

D. Kumar; A. Syamal; L. K. Sharma

2008-01-01

361

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

PubMed

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

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

2010-07-01

362

Synthesis, structure, and single-molecule magnetic properties of rare-earth sandwich complexes with mixed phthalocyanine and Schiff base ligands.  

PubMed

Double- and quadruple-decker complexes of rare-earth metals with mixed phthalocyanine and Schiff base ligands have been synthesized and structurally and magnetically characterized. These complexes (see picture: Dy?pink, Ca?green, N?blue, C?black) extend the scope of sandwich-type tetrapyrrole-based rare-earth molecular materials. PMID:23281042

Wang, Hailong; Cao, Wei; Liu, Tao; Duan, Chunying; Jiang, Jianzhuang

2013-02-11

363

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

PubMed

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

Chohan, Zahid H; Sumrra, Sajjad H

2010-10-01

364

New Cu(II) complexes with polydentate chelating Schiff base ligands: Synthesis, structures, characterisations and biochemical activity studies  

Microsoft Academic Search

We have reported herein the synthesis of three new Cu(II) complexes of tri- and tetradentate Schiff base ligands containing\\u000a N3 or N4 donor set along with terminal NNN? or SCN? ligands: [L1Cu(NCS)]ClO4 (1), [L2Cu(NCS)2] (2) and [L3Cu(NNN)]ClO4 (3) [L1 = NC5H4C(CH3)=N(CH2)3N=C(CH3)C5H4N, L2= Me2N–(CH2)3–N=C(CH3)C5H4N and L3 = NC5H4CH=N–(CH2)4–N=CHC5H4N]. The complexes have been systematically characterised by elemental, spectroscopic and electrochemical techniques. Antimicrobial\\u000a activities

Brajagopal Samanta; Joy Chakraborty; C. R. Choudhury; S. K. Dey; D. K. Dey; S. R. Batten; P. Jensen; Glenn P. A. Yap; Samiran Mitra

2007-01-01

365

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

Microsoft Academic Search

Two new macrocyclic Schiff base ligands L1 and L2 from [1+1] and [2+2] condensation reaction, respectively, have been obtained in a one-pot synthesis starting from 1,4-bis(2-formylphenyl)piperazine and 2,2-dimethyl-propylendiamine. Unfortunately, because of the low solubility of two products, we were unable to separate them effectively. Macrocyclic Schiff base complexes [NiL1](ClO4)2, [CuL1](ClO4)2 and [ZnL1](ClO4)2 were prepared from the reaction of a mixture

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

2010-01-01

366

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)

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

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

2012-10-01

367

Synthesis and Structural Characterization of a Nickel(II) Complex with Unsymmetrical NNO-Donor Schiff Base like Hydrazone Ligand  

Microsoft Academic Search

\\u000a Abstract  The nickel(II) complex Ni[C5H4N–C(CH3)=N–N=C(O)–C6H5]2 (1), containing the potentially tridentate Schiff base like hydrazone ligand (LH) which is the 1:1 condensation product of benzhydrazide\\u000a and 2-acetylpyridine, was prepared and characterized by IR and UV–Vis spectra, thermal analysis and single crystal X-ray diffraction\\u000a measurements. Structural investigation shows that the molecule prefers a monoclinic lattice, having space group Cc, a = 10.248(6), b = 19.692(11), c = 12.281(7) Å,

Amitabha Datta; Nien-Tsu Chuang; Jui-Hsien Huang

368

Synthesis and DNA binding studies of Mg(II) complex of Schiff base derived from vanillin and L-tryptophan.  

PubMed

The Mg(II) complex of Schiff base (K[HL]) derived from vanillin and L-tryptophan could bind with herring sperm DNA. The binding behaviors between them in physiological pH environment (pH 7.40) have been studied by spectroscopy, cyclic voltammetry and viscosity methods. Binding ratios of n(Mg(II)): n(K[HL]) = 1:1 and n(Mg(II)L): n(DNA) = 5:1 were confirmed. The obtained thermodynamic parameters suggest that the interaction between Mg(II)L and DNA is driven mainly by entropy. Combined with fluorimeteric studies, cyclic voltammetry, CD spectroscopy and viscosity methods, the results indicate the interaction modes between Mg(II)L and DNA are mainly with intercalation and involving some electrostatic interaction. PMID:21259163

Zhang, Yan; Wang, Xingming; Ding, Lisheng

2011-01-01

369

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

PubMed

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

Asadi, Mozaffar; Torabi, Susan; Mohammadi, Khosro

2014-03-25

370

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)

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.

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

371

Synthesis, structural characterization, fluorescence, antimicrobial, antioxidant and DNA cleavage studies of Cu(II) complexes of formyl chromone Schiff bases  

NASA Astrophysics Data System (ADS)

Cu(II) complexes have been synthesized from different Schiff bases, such as 3-((2-hydroxy phenylimino)methyl)-4H-chromen-4-one (HL1), 2-((4-oxo-4H-chromen-3-yl)methylneamino) benzoicacid (HL2), 3-((3-hydroxypyridin-2-ylimino)methyl)-4H-chromen-4-one (HL3) and 3-((2-mercaptophenylimino)methyl)-4H-chromen-4-one (HL4). The complexes were characterized by analytical, molar conductance, IR, electronic, magnetic, ESR, thermal, powder XRD and SEM studies. The analytical data reveal that metal to ligand molar ratio is 1:2 in all the complexes. Molar conductivity data indicates that all the Cu(II) complexes are neutral. On the basis of magnetic and electronic spectral data, distorted octahedral geometry is proposed for all the Cu(II) complexes. Thermal behaviour of the synthesized complexes illustrates the presence of lattice water molecules in the complexes. X-ray diffraction studies reveal that all the ligands and their Cu(II) complexes have triclinic system with different unit cell parameters. Antimicrobial, antioxidant and DNA cleavage activities indicate that metal complexes exhibited greater activity as compared with ligands.

Kavitha, P.; Saritha, M.; Laxma Reddy, K.

2013-02-01

372

Synthesis, characterization, DNA binding, photo-induced DNA cleavage, and antimicrobial activity of metal complexes of a Schiff base derived from bis(3-aminophenyl)malonamide  

Microsoft Academic Search

The peptide linkage Schiff base (H2L) and its complexes have been synthesized and fully characterized by elemental analysis, UV–Vis, FTIR, H-NMR, C-NMR, EPR, and FAB-mass spectra. The stoichiometry of the complexes is [ML] (where M = Cu(II), Co(II), Ni(II), Zn(II), and VO(IV)). All the complexes exhibit square-planar geometry except the vanadyl complex which has square-pyramidal geometry. Interactions of the complexes

N. Raman; A. Sakthivel; R. Jeyamurugan

2009-01-01

373

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

NASA Astrophysics Data System (ADS)

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.

Arun, Thesingu Rajan; Raman, Natarajan

2014-06-01

374

Synthesis and characterization of some Schiff base transition metal complexes derived from vanillin and L(+)alanine  

Microsoft Academic Search

The cobalt(II), nickel(II), copper(II) and zinc(II)-vanillidene-L(+)alanine complexes were synthesized and characterized by\\u000a elemental analysis, conductivity measurements, magnetic behavior, infrared, electronic spectral measurements, X-ray powder\\u000a diffraction and biological studies. The conductance measurements indicate that all the complexes are non-electrolytes. The\\u000a infrared spectra indicate the coordination of imino nitrogen, phenolic oxygen and carboxylato oxygen atoms. The electronic\\u000a spectral measurements demonstrate that cobalt(II)

R. Selwin Joseyphus; C. Justin Dhanaraj; M. Sivasankaran Nair

2006-01-01

375

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

NASA Astrophysics Data System (ADS)

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

Çelikbilek, ?eyma; Koç, Ziya Erdem

2014-05-01

376

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

NASA Astrophysics Data System (ADS)

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

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

2012-12-01

377

Magnetic and catalytic properties of a new copper(II)–Schiff base 2D coordination polymer formed by connected helical chains  

Microsoft Academic Search

A dicyanamide bridged 2D polynuclear complex of copper(II) having molecular formula [Cu2(L)(?1,5-dca)2]n (1) has been synthesized using the Schiff base ligand N,N?-bis(salicylidene)-1,3-diaminopentane, (H2L) and sodium dicyanamide (dca). The complex presents a 2D hexagonal structure formed by 1,5-dca singly bridged helical chains connected through double 1,5-dca bridges. The chelating characteristics of the H2L Schiff base ligand results in the formation of

Dipali Sadhukhan; Aurkie Ray; Ray J. Butcher; Carlos J. Gómez García; Bülent Dede; Samiran Mitra

2011-01-01

378

Helical-chain copper(II) complexes and a cyclic tetranuclear copper(II) complex with single syn-anti carboxylate bridges and ferromagnetic exchange interactions.  

PubMed

Tridentate Schiff-base carboxylate-containing ligands, derived from the condensation of 2-imidazolecarboxaldehyde with the amino acids beta-alanine (H2L1) and 2-aminobenzoic acid (H2L5) and the condensation of 2-pyridinecarboxaldehyde with beta-alanine (HL2), D,L-3-aminobutyric acid (HL3), and 4-aminobutyric acid (HL4), react with copper(II) perchlorate to give rise to the helical-chain complexes [[Cu(mu-HL1)(H2O)](ClO4)]n (1), [[Cu(mu-L2)(H2O)](ClO4).2H2O]n (2), and [[Cu(mu-L3)(H2O)](ClO4).2H2O]n (3), the tetranuclear complex [[Cu(mu-L4)(H2O)](ClO4)]4 (4), and the mononuclear complex [Cu(HL5)(H2O)](ClO4).1/2H2O (5). The reaction of copper(II) chloride with H2L1 leads not to a syn-anti carboxylate-bridged compound but to the chloride-bridged dinuclear complex [Cu(HL1)(mu-Cl)]2 (6). The structures of these complexes have been solved by X-ray crystallography. In complexes 1-4, roughly square-pyramidal copper(II) ions are sequentially bridged by syn-anti carboxylate groups. Copper(II) ions exhibit CuN2O3 coordination environments with the three donor atoms of the ligand and one oxygen atom belonging to the carboxylate group of an adjacent molecule occupying the basal positions and an oxygen atom (from a water molecule in the case of compounds 1-3 and from a perchlorate anion in 4) coordinated in the apical position. Therefore, carboxylate groups are mutually cis oriented and each syn-anti carboxylate group bridges two copper(II) ions in basal-basal positions with Cu...Cu distances ranging from 4.541 A for 4 to 5.186 A for 2. In complex 5, the water molecule occupies an equatorial position in the distorted octahedral environment of the copper(II) ion and the Cu-O carboxylate distances in axial positions are very large (>2.78 A). Therefore, this complex can be considered as mononuclear. Complex 6 exhibits a dinuclear parallel planar structure with Ci symmetry. Copper(II) ions display a square-pyramidal coordination geometry (tau = 0.06) for the N2OCl2 donor set, where the basal coordination sites are occupied by one of the bridging chlorine atoms and the three donor atoms of the tridentate ligand and the apical site is occupied by the remaining bridging chlorine atom. Magnetic susceptibility measurements indicate that complexes 1-4 exhibit weak ferromagnetic interactions whereas a weak antiferromagnetic coupling has been established for 6. The magnetic behavior can be satisfactorily explained on the basis of the structural data for these and related complexes. PMID:11232828

Colacio, E; Ghazi, M; Kivekäs, R; Moreno, J M

2000-06-26

379

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

PubMed

Schiff base disulfide ligands (H2L(1-6)) were synthesized from the condensation of cystamine with salicylaldehyde(H2L(1)), 5-chlorosalicylaldehyde(H2L(2)), o-vanillin(H2L(3)), 2-hydroxyacetophenone(H2L(4)), 3-methyl-2-hydroxyacetophenone(H2L(5)), and 2-hydroxy-1-naphthaldehyde(H2L(6)). H2L(1-6) reacts with the ruthenium precursor complex [RuHCl(CO)(PPh3)3] in benzene giving rise to six new ruthenium(II) complexes of general formula [Ru(CO)L(1-6)]. Characterization of the new complexes was carried out by using elemental and spectral (IR, UV-Vis, NMR ((1)H and (13)C) and Mass) techniques. An octahedral geometry was assigned for all the complexes based on the spectral data obtained. The catalytic efficiency of the new complexes in aldehyde to amide conversion in the presence of NaHCO3, N-alkylation of aniline in the presence of t-BuOK, and transfer hydrogenation of ketones in the presence of iPrOH/KOH reactions were studied. Furthermore, the effect of solvents and catalyst/substrate ratio on the catalytic aldehyde to amide conversion were also discussed. PMID:24747860

Prakash, Govindan; Viswanathamurthi, Periasamy

2014-08-14

380

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

NASA Astrophysics Data System (ADS)

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.

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

2014-06-01

381

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)

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.

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

382

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

Microsoft Academic Search

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

N. Raman; S. Ravichandran

2005-01-01

383

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)

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

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

2011-11-01

384

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

PubMed Central

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

Okamoto, Yu; Nidaira, Keisuke; Akitsu, Takashiro

2011-01-01

385

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

NASA Astrophysics Data System (ADS)

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

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

2007-05-01

386

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

Microsoft Academic Search

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

Fethi Bedioui

1995-01-01

387

Complexing behaviour of Schiff bases derived from 3-acetyl-4-hydroxy-6-methyl-2H-pyran-2-one  

SciTech Connect

By reaction of 3-acetyl-r-hydroxy-6-methyl-2H-pyran-2-one (HDh, dehydroacetic acid) with H{sub 2}NR (R = Me, nPr or nBu) and HN(CH{sub 2}CH{sub 2}NH{sub 2}){sub 2} the related Schiff bases HDHR and H{sub 2}Dh{sub 2}T were obtained. All ligands react with uranyl nitrate yielding 1:2 adducts. In the uranyl acetate-HDhR systems adduct formation and ligand deprotonation should occur, depending on solvent, reaction time and hydration, whereas H{sub 2}Dh{sub 2}T undergoes total deprotonation in the presence of uranyl acetate to give (UO{sub 2}(Dh{sub 2}T)). Ligands and complexes have been characterized by ir and nmr ({sup 1}H and {sup 13}C) spectroscopy and, in some cases, by thermogravimetric measurements. The action of the amines on the preformed (UO{sub 2}(Dh){sub 2}) complex is discussed.

Fregona, D.; Faraglia, G. (Metallorganica e Analitica dell'Univ., Padova (Italy)); Sitran, S. (Inst. di Chimica e Tecnologia dei Radioelementi del C.N.R., Padova (Italy))

1992-01-01

388

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

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.

Yernale, Nagesh Gunvanthrao; Bennikallu Hire Mathada, Mruthyunjayaswamy

2014-01-01

389

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

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, (1)H 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

Yernale, Nagesh Gunvanthrao; Bennikallu Hire Mathada, Mruthyunjayaswamy

2014-01-01

390

Synthesis, spectral characterization, catalytic and antibacterial studies of new Ru(III) Schiff base complexes containing chloride/bromide and triphenylphosphine/arsine as co-ligands  

NASA Astrophysics Data System (ADS)

A new Ru(III) Schiff base complexes of the type [RuX(EPh 3)L] (X = Cl/Br; E = P/As; L = dianion of the Schiff bases were derived by the condensation of 1,4-diformylbenzene with o-aminobenzoic acid/ o-aminophenol/ o-aminothiophenol in the 1:2 stoichiometric ratio) have been synthesized from the reactions of [RuX 3(EPh 3) 3] with appropriate Schiff base ligands in benzene in the 2:1 stoichiometric ratio. The new complexes have been characterized by analytical, spectral (IR, electronic, 1H, 13C NMR and ESR), magnetic moment and electrochemical studies. An octahedral structure has been tentatively proposed for all these new complexes. All the new complexes have been found to be better catalyst for the oxidation of alcohols using molecular oxygen as co-oxidant at ambient temperature and aryl-aryl coupling reactions. These complexes were also subjected to antibacterial activity studies against Escherichia coli, Aeromonas hydrophilla and Salmonella typhi.

Arunachalam, S.; Padma Priya, N.; Jayabalakrishnan, C.; Chinnusamy, V.

2009-10-01

391

Synthesis, structure, magnetic properties and DFT calculations of two hydroxo-bridged complexes based on Mn(III)(Schiff-Bases).  

PubMed

Two hydroxo-bridged complexes, {[Mn(III)(3-CH(3)O)salen](2)[Cr(III)(salen)(OH)(2)]}ClO(4)·6H(2)O (1) and {[Mn(III)(5-CH(3))salen](2)(OH)}ClO(4)·3H(2)O (2) [salen = N,N'-ethylenebis(salicylideneiminato) dianion], have been synthesized by the hydrolysis of the corresponding Mn(III)(Schiff-Bases) derivatives and [Cr(salen)(H(2)O)(2)]Cl precursors. X-Ray structure characterization reveals the discrete linear arched trinuclear structure of 1 and the 1D chain arrangement of 2. Magnetic experimental data and density functional theory (DFT) calculations both indicate the dominant antiferromagnetic interaction mediated by the hydroxo-bridges in both 1 and 2. Frequency-dependent AC susceptibilities reveal slow relaxation of 1 in low temperature. It is worth noting that the structure and magnetic properties of 1 is comparable to a reported cyano-bridged SMM, K[(5-Brsalen)(2)(H(2)O)(2)Mn(2)Cr(CN)(6)]·2H(2)O. PMID:21541410

Zhou, Hong-Bo; Wang, Hui-Sheng; Chen, Ying; Xu, Yong-Lu; Song, Xiao-Jiao; Song, You; Zhang, Yi-Quan; You, Xiao-Zeng

2011-06-14

392

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

NASA Astrophysics Data System (ADS)

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).

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

2014-01-01

393

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

PubMed

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). PMID:24044990

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

2014-01-24

394

(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

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

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

2014-01-01

395

Synthesis, characterization, and protein tyrosine phosphatases inhibition activities of oxovanadium(IV) complexes with Schiff base and polypyridyl derivatives.  

PubMed

Seven new mixed-ligand vanadyl complexes, [V(IV)O(5-Br-SAA)(NN)] and [V(IV)O(2-OH-NAA)(NN)] (1-7) (5-Br-SAA for 5-bromosalicylidene anthranilic acid, 2-OH-NAA for 2-hydroxy-1-naphthaldehyde anthranilic acid and NN for N,N'-donor heterocyclic base, namely, 2,2'-bipyridine (bpy, 1 and 5), 1,10-phenanthroline (phen, 2 and 6), dipyrido[3,2-d:2',3'-f]quinoxaline (dpq, 3 and 7), dipyrido[3,2-a:2',3'-c]phenazine (dppz, 4)), were synthesized and characterized. X-ray crystal structure of [V(IV)O(5-Br-SAA)(phen)] revealed a distorted octahedral geometry with the Schiff base ligand coordinated in a tridentate ONO-fashion and the phenanthroline ligand in a bidentate fashion. Density-functional theory (DFT) calculations suggest a similar structure and the same coordination mode for all the other oxovanadium complexes synthesized. Biochemical assays demonstrate that the mixed-ligand oxovanadium(IV) complexes are potent inhibitors of protein tyrosine phosphatase 1B (PTP1B), with IC(50) values approximately 41-75 nM. Kinetics assays suggest that the complexes inhibit PTP1B in a competitive manner. Notably, they had moderate selectivity of PTP1B over T-cell protein tyrosine phosphatase (TCPTP) (about 2-fold) and good selectivity over Src homology phosphatase 1 (SHP-1) (about 4 approximately 7-fold). Thus, these mixed-ligand complexes represent a promising class of PTP1B inhibitors for future development as anti-diabetic agents. PMID:20542335

Yuan, Caixia; Lu, Liping; Wu, Yanbo; Liu, Zhiwei; Guo, Maolin; Xing, Shu; Fu, Xueqi; Zhu, Miaoli

2010-09-01

396

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

PubMed

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

Sato, Hisako; Mori, Yukie; Yamagishi, Akihiko

2013-05-21

397

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)

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.

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

2007-07-01

398

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

PubMed

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, (1)H NMR, (13)C 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 ZnL(2)A has lower MIC values than ampicillin for P. aeruginosa ATCC 27853 strain. PMID:23274224

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

2013-02-15

399

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)

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.

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

2008-08-01

400

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

PubMed

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., (1)H NMR, (13)C NMR, ESR, thermal analyses (TGA and DTG) and magnetic measurements. The results showed that the Schiff-base ligand acts as bi-negative tridentate through the azomethine nitrogen, the deprotonated carboxylate oxygen and the enolic carbonyl oxygen. The optical band gaps measurements indicated the semi-conducting nature of these complexes. Molecular docking was used to predict the binding between the Schiff base ligand with the receptor of prostate cancer mutant H874Y. The interactions between the Cu(II) complex and calf thymus DNA (CT-DNA) have been studied by UV spectra. The results confirm that the Cu(II) complex binds to CT-DNA in an intercalative mode. PMID:24858353

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

2014-11-11

401

Synthesis, characterization, crystal structure and antibacterial activities of transition metal(II) complexes of the schiff base 2-[(4-methylphenylimino)methyl]-6-methoxyphenol.  

PubMed

Five transition metal(II) complexes, [ML(2)Cl(2)] 1 approximately 5, were synthesized from the reaction of MCl(2) x nH(2)O (M = Mn, Co, Ni, Cu, Cd) and the Schiff base ligand 2-[(4-methylphenylimino)methyl]-6-methoxyphenol (C(15)H(15)NO(2), L), obtained by condensation of o-vanillin (2-hydroxy-3-methoxybenzaldehyde) with p-toluidine. They were characterized by elemental analysis, molar conductance, FT-IR spectra, thermal analysis. The structure of complex 1 was determined by single-crystal X-ray diffraction. Its crystal structure is of monoclinic system, space group P2(1)/c with a = 9.0111(18) A, b = 11.222(2) A, c =28.130 (6) A, alpha = 90 masculine, beta = 92.29(3) masculine, gamma = 90 masculine, V = 2867.6(10) A(3), Z = 4. The Mn atom is six-coordinate and displays distorted octahedral geometry.The Schiff base ligand and its complexes have been tested in vitro to evaluate their antibacterial activity against bacteria, viz., Escherichia coli, Staphylococcus aureus and Bacillus subtilis. It has been found that the complexes have higher activity than the corresponding free Schiff base ligand against the same bacteria. PMID:19471194

Yu, Yu-Ye; Xian, Hui-Duo; Liu, Jian-Feng; Zhao, Guo-Liang

2009-01-01

402

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

Microsoft Academic Search

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

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

2011-01-01

403

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

Microsoft Academic Search

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

M. Sivasankaran Nair; C. Ravi Samuel Raj

2009-01-01

404

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

PubMed Central

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

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

2010-01-01

405

Molecular design of new magnetically active copper complexes with heteroaromatic schiff bases and azo compounds  

Microsoft Academic Search

Copper chelates with tridentate ligands containing pyridine or pyrazole ring at the azomethine or azo fragment were synthesized\\u000a by chemical electrochemical methods, and their structure was characterized by the EXAFS spectra. Thermal magnetochemical analysis\\u000a of the complexes revealed antiferromagnetic exchange interaction in all complexes. The exchange interaction parameter of the\\u000a complex containing an N-tosylamino group in the ortho position with

A. S. Burlov; A. I. Uraev; V. N. Ikorskii; S. A. Nikolaevskii; Yu. V. Koshchienko; I. S. Vasil’chenko; D. A. Garnovskii; V. G. Vlasenko; Ya. V. Zubavichus; L. N. Divaeva; G. S. Borodkin; A. D. Garnovskii

2008-01-01

406

Synthesis, crystal structures and magnetic studies of dicyanamide bridged two new 1D copper(II) complexes  

Microsoft Academic Search

Two new dicyanamide bridged 1D polynuclear copper(II) complexes [Cu(L1){?1,5-N(CN)2}]n (1) [L1H=C6H5C(O)NHNC(CH3)C5H4N] and [Cu(L2){?1,5-N(CN)2}]n (2) [L2H=C6H5C(O)CHC(CH3)NCH2CH2N(CH3)2] have been synthesised and structures of both the complexes and their crystal packing arrangements have been established by X-ray crystallography. For complex 1, a tridentate hydrazone ligand (L1H) obtained by the condensation of benzhydrazide and 2-acetylpyridine is used, whereas a tridentate Schiff base (L2H) derived

Soma Sen; Samiran Mitra; David L. Hughes; Georgina Rosair; Cédric Desplanches

2007-01-01

407

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

Microsoft Academic Search

Co(II), Ni(II), Cu(II) and Zn(II) complexes of the Schiff base derived from vanillin and dl-?-aminobutyric acid were synthesized and characterized by elemental analysis, IR, electronic spectra, conductance measurements, magnetic measurements, powder XRD and biological activity. The analytical data show the composition of the metal complex to be [ML(H2O)], where L is the Schiff base ligand. The conductance data indicate that

M. Sivasankaran Nair; R. Selwin Joseyphus

2008-01-01

408

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

NASA Astrophysics Data System (ADS)

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

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

2014-08-01

409

Some new Cu(II) complexes containing an ON donor Schiff base: Synthesis, characterization and antibacterial activity  

Microsoft Academic Search

Six new copper(II) complexes, CuLCl·H2O (1), CuL(NO3)·2H2O (2), [Cu(L)2] (3), CuL(SCN)·2H2O (4), CuL(ClO4)·2H2O (5) and (CuL)2(SO4)·4H2O (6), where HL=1-phenyl-2,3-dimethyl-4-(N-2-hydroxy-4-methoxy-benzaldehyde)-3-pyrazolin-5-one, have been synthesized. The characterization of the newly formed compounds was done by 1H NMR, UV–Vis, IR, ESR spectroscopy, elemental analysis and molar electric conductivity. The crystal structure of 1-phenyl-2,3-dimethyl-4-(N-2-hydroxy-4-methoxy-benzaldehyde)-3-pyrazolin-5-one has been determined by X-ray diffraction studies, as well as the

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

2011-01-01

410

Synthesis of Mononuclear Metal Complexes with Some Tetradentate Schiff Base Ligands  

Microsoft Academic Search

A series of Cu(II), Ni(II) and Co(II) complexes with N,N?-bis-[5-X-salicylidene]-2,2?-diaminodibenzyl [H2-XSalDDB (X?H, CH3, Br)] have been prepared. The metal complexes were characterized on the basis of elemental analyses, electrical conductance, magnetic susceptibility, spectral and thermal studies. All of the complexes are non-electrolytes of 1:1 (M:L) stoichiometry. The room temperature magnetic susceptibility and electronic spectral data support a pseudo-tetrahedral geometry for

N. V. Thakkar; R. M. Patil

2000-01-01

411

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

NASA Astrophysics Data System (ADS)

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.

Salavati-Niasari, Masoud; Bazarganipour, Mehdi

2009-06-01

412

Substituent Effects on Spin State in a Series of Mononuclear Manganese(III) Complexes with Hexadentate Schiff-Base Ligands.  

PubMed

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

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

413

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

PubMed

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

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

2007-08-20

414

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

NASA Astrophysics Data System (ADS)

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.

Yadav, Sunita; Singh, R. V.

2011-01-01

415

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

Microsoft Academic Search

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

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

2000-01-01

416

Synthesis, characterization and thermal study of some tetradentate Schiff base transition metal complexes  

Microsoft Academic Search

Several mononuclear Co(II), Ni(II), Cu(II), and Fe(II) complexes of tetradentate salpren-type diimine, obtained from 3,5-di-tert-butyl-2-hydroxybenzaldehyde and 1,3-diaminopropane have been prepared and characterized by analytical, spectroscopic (FT-IR,\\u000a UV–VIS) techniques, magnetic susceptibility measurements and thermogravimetric analyses (TG). The thermodynamic and thermal\\u000a properties of complexes have been investigated. For further characterization Direct Insertion Probe-Mass Spectrometry (DIP-MS)\\u000a was used and the fragmentation pattern and

Fatih Do?an; Mahmut Ulusoy; Ömer F. Öztürk; ?smet Kaya; Bekir Salih

2009-01-01

417

Synthesis and characterization of tin(II) complexes of fluorinated Schiff bases derived from amino acids.  

PubMed

New tin(II) complexes of general formula Sn(L)(2) (L=monoanion of 3-methyl-4-fluoro-acetophenone phenylalanine L(1)H, 3-methyl-4-fluoro-acetophenone alanine L(2)H, 3-methyl-4-fluoro acetophenone tryptophan L(3)H, 3-methyl-4-fluoro-acetophenone valine L(4)H, 3-methyl-4-fluoro-acetophenone isoleucine L(5)H and 3-methyl-4-fluoro-acetophenone glycine L(6)H) have been prepared. It is 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 ((1)H, (13)C, (19)F and (119)Sn NMR) spectral studies. The ligands act as bidentate towards metal ions, via the azomethine nitrogen and deprotonated oxygen of the respective amino acid. Elemental analyses and NMR spectral data of the ligands with their tin(II) complexes agree with their proposed square pyramidal structures. A few representative ligands and their tin complexes have been screened for their antibacterial activities and found to be quite active in this respect. PMID:20381414

Singh, Har Lal

2010-07-01

418

Synthesis and characterization of 2-quinoxalinol Schiff-base metal complexes  

Microsoft Academic Search

The reaction of uranyl acetate with (2,2?-(1E,1?E)-(2-benzyl-3-hydroxyquinoxaline-6,7-diyl)bis(azan-1-yl-1-ylidene)bis(methan-1-yl-1-ylidene) diphenol) (H2L1) at room temperature in methanol and chloroform yields the UO2L1 complex. Crystals were grown through solvent diffusion of the ligand–metal complex in dimethyl formamide with diethyl ether to prepare: UO2L1·DMF (1). Complexes with 2,2?-(1E,1?E)-(2-benzyl-3-hydroxyquinoxaline-6,7-diyl)bis(azan-1-yl-1-ylidene)bis(methan-1-yl-1-ylidene)dibenzene-1,4-diol (H2L2) and 2,2?-(1E,1?E)-(2-hydroxy-3-isopropylquinoxaline-6,7-diyl)bis(azan-1-yl-1-ylidene)bis(methan-1-yl-1-ylidene)diphenol (H2L3) were also prepared, and crystals of the uranyl complexes (UO2L2·DMF (2) and (3))

Xianghong Wu; Mohan S. Bharara; Travis H. Bray; Brandon K. Tate; Anne E. V. Gorden

2009-01-01

419

Near-Infrared Luminescent PMMA-Supported Metallopolymers Based on Zn-Nd Schiff-Base Complexes.  

PubMed

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

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

2014-06-16

420

Copper(II) complexes of N 4 tetradentate ligands with flexible alkyl spacers: Crystal structure, DNA binding and cleavage studies  

Microsoft Academic Search

Mononuclear copper(II) complexes, [Cu L1] (ClO4)2 (1), [Cu L2] (ClO4)2 (2) and [Cu L3] (ClO4)2 (3) with quadridentate Schiff base ligands L1 (N,N?-bis-pyridin-2-ylmethyl-butane-1,4-diimine), L2 (N,N?-bis-pyridin-2-ylmethyl-pentane-1,5-diimine) and L3 (N,N?-bis-pyridin-2-ylmethyl-hexane-1,6-diimine) have been synthesized and characterized. The crystal structure data of 1 reveals the existence of the complex in two different geometries, namely a square pyramid and a distorted octahedron, which eventually leads

Varadarajan Uma; Alfonso Castineiras; Balachandran Unni Nair