Biologically Active Co(II) and Ni(II) Complexes of N-(2-Thienylmethylene)-2-Aminothiadiazole

Co(II) and Ni(II) complexes Schiff base, N-(2-thienylmethylene)-2-aminothiadiazole have been prepared and characterized by their physical, spectral and analytical data. The title Schiff-base acts as NNS donor tridentate during the complexation reaction with these metal ions having a composition, [M(L)(2)]X(n) where M=Co(II) or Ni(II), L=, X=NO(3) (-), SO(4) (2-), C(2)O(4) (2-) or CH(3)CO(2) (-) and n=1 or 2 and show an octahedral geometry. In order to evaluate the effect anions upon chelation, the Schiff-base and its new complexes have been screened for their antibacterial activity against bacterial strains e.g., Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa.     

Synthesis, Characterization and Biological Evaluation of Co(II), Cu(II), Ni(II) and Zn(II) Complexes With Cephradine

Some Co(II), Cu(II), Ni(II) and Zn(II) complexes of antibacterial drug cephradine have been prepared and characterized by their physical, spectral and analytical data. Cephradine acts as bidentate and the complexes have compositions, [M(L)(2)X(2)] where [M = Co(II), Ni(II) and Zn(II), L = cephradine and X = Cl(2)] showing octahedral geometry, and [M(L)(2)] where [M = Cu(II), L = cephradine] showing square planar geometry. In order to evaluate the effect of metal ions upon chelation, eephradine and its complexes have been screened for their antibacterial activity against bacterial strains, Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa.     

Antibacterial Role of SO(4), NO(3), C(2)O(4) and CH(3)CO(2) Anions on Cu(II) and Zn(II) Complexes of a Thiadiazole-derived Pyrrolyl Schiff Base

A condensation reaction of 2-amino-1,3,4-thiadiazole with 2-pyrrolecarboxaldehyde to form tridentate NNN donor Schiff base has been performed. The prepared Schiff base was further used for the formation of metal complexes having stoichiometry [M(L)(2)]X(n), where M=Cu(II) or Zn(II), L=N-(2-pyrrolylmethylene)-2-amino-1,3,4-thiadiazole, X=SO(4) (2-), NO(3) (-), C(2)O(4) (2-) or CH(3)CO(2-) and n=1 or 2. The new compounds described here have been characterized by their physical, spectral and analytical data, and have been screened against several bacterial strains such as Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa. The antibacterial potency of the Schiff base increased upon chelation/complexation, having the same metal ion (cation) but different anions opening up a novel approach in finding new ways to fight against antibiotic resistant strains.     

Synthesis, Characterization and Biological Properties of Tridentate NNO, NNS and NNN Donor Thiazole-Derived Furanyl, Thiophenyl and Pyrrolyl Schiff Bases and Their Co(II), Cu(II), Ni(II) and Zn(II) Metal Chelates

2-Aminothiazole undergoes condensation reactions with furane-, thiophene- and pyrrole-2-carboxylaldehyde to give tridentate NNO, NNS and NNN Schiff bases respectively. These tridentate Schiff bases formed complexes of the type [M (L)(2)]X(2) where [M=Co(II), Cu(II), Ni(II) or Zn(II), L=N-(2-furanylmethylene)-2-aminothiazole (L(1)), N-(2-thiophenylmethylene)-2-aminothiazole (L(2), N-(2-pyrrolylmethylene)-2-aminothiazole (L(3)) and X=Cl. The structures of these Schiff bases and of their complexes have been determined on the basis of their physical, analytical and spectral data. The screening results of these compounds indicated them to possess excellent antibacterial activity against tested pathogenic bacterial organisms e.g., Escherichia coli, Staphylococcus aureous and Pseudomonas aeruginosa. However, in comparison, their metal chelates have been shown to possess more antibacterial activity than the uncomplexed Schiff bases.     

Symmetric 1,1'-Dimethylferrocene-Derived Amino Acids: Their Synthesis, Characterization, Ligational and Biological Properties With Cu(II), Co(II) and Ni(II) Ions

Some novel symmetric 1,1'-dimethylferrocene derived amino acids have been prepared by the reaction of 1,1'-ferrocenedimethyldichloride with amino acids (glycine, alanine, phenylalanine and tyrosine). Their Cu(II), Co(II) and Ni(II) complexes, of the type [M(L)] where [M = Cu(II) and L = L(1)-L(5)] and [M(L)Cl(2)] where [M-Co(II)and Ni(II), L = L(1)-L(5)] have been prepared. The dicarboxylic acids and their metal complexes were characterized by their physical, analytical and spectral data. The [M(L)] complexes showed a square planar geometry whereas an octahedral geometry was observed for [M(L)Cl(2)] complexes. The title dicarboxylic acids and their metal complexes have also been screened for their antibacterial activity.     

Antibacterial Co(II), Cu(II), Ni(II) and Zn(II) Complexes of Thiadiazoles Schiff Bases

Schiff bases were obtained by condensation of 2-amino-l,3,4-thiadiazole with 5-substituted-salicylaldehydes which were further used to obtain complexes of the type [M(L)(2)]Cl(2), where M=Co(II), Cu(II), Ni(II) or Zn(II). The new compounds described here have been characterized by physical, spectral and analytical data, and have been screened for antibacterial activity against several bacterial strains such as Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa. The antibacterial potency of these Schiff bases increased upon chelation/complexation, against the tested bacterial species, opening new aproaches in the fight against antibiotic resistant strains.     

Ni (II), Cu (II) and Zn (II) Metal Chelates With Some Thiazole Derived Schiff-Bases: Their Synthesis, Characterization and Bactericidal Properties

A number of thiazole derived tridentate Schiff-bases (LH) and its metal chelates of the type [M(L)(2)X] where M=Ni(II), Cu(II) and Zn(II), L=substituted salicylaldehyde (5-H, 5-CH(3), 5-OCH(3), 5-NO(2) and 5-Cl) and X=CI have been synthesized and characterized with the help of elemental analyses, conductivity measurements, magnetic moments, UV-Vis, IR and NMR spectral data. An octahedral structure for Ni(II) and Zn(II) and a distorted octahedral structure for Cu(II) chelates have been proposed. All the Schiff-bases and their metal chelates have been screened for their biological activity against Escherichia coli, Staphylococcus aureous , Pseudomonas aeruginosa and Klebsiella pneumonae and in comparison, the metal chelates have been shown to possess more antibacterial activity than the uncomplexed Schiff-bases.     

Synthesis, Characterization and Antiproliferative Activity of the Co(II), Ni(II), Cu(II), Pd(II) and Pt(II) Complexes of 2-(4-Thiazolyl)Benzimidazole (Thiabendazole)

Complexes of 2-(4-thiazolyi)benzimidazole (thiabendazole, THBD) with Co(II), Ni(II), Cu(ll) of general formula ML(2)(NO(3))(2) H(2)O and complexes of Pd(II) and Pt(II) of general formula ML2Cl(2) H(2)O have been obtained and characterized by elemental analyses, IR and far IR spectroscopy and magnetic measurements. The X-ray crystal structure of the copper(II) complex has been determined. The in vitro cell proliferation inhibitory activity of these compounds was examined against human cancer cell lines A 549 (lung carcinoma), HCV-29 T (urinary bladder carcinoma), MCF-7 (breast cancer), T47D (breast cancer), MES-SA (uterine carcinoma) and HL-60 (promyelocytic leukemia). Pt-THBD has been found to exhibit an antileukemic activity of the HL-60 line cells matching that of an arbitrary criterion.     

AGGREGATION BEHAVIOR OF COBALT(II), NICKEL(II), AND COPPER(II) BIS(2-ETHYLHEXYL) PHOSPHATE COMPLEXES IN n-HEPTANE

ABSTRACT

The solution behavior of divalent transition metal-bis(2-ethylhexyl) phosphate (M(DEHP)₂, M = cobalt, nickel or copper) complexes in n-heptane have been investigated by vapor pressure osmometry, viscometry and dynamic light scattering. Co(DEHP)₂ complexes tend to form large macromolecular species with a mean aggregation number N_agg as large as 225, and the size of the macromolecular species decreases with increasing Co(DEHP)₂ concentration. In contrast, Cu(DEHP)₂ complexes tend to form small macromolecular species N_agg = 4-8 which increase in size with increasing Cu(DEHP)₂ concentration. On the other hand, Ni(DEHP)₂ complexes (and Ni(DEHP)₂-2H₂O complexes when the molar ratio of H₂O     

Synthesis and some properties of PVC-bound dimethylglyoxime complexes of Co(II), Ni(II), and Cu(II)

Poly(vinyl chloride) (PVC) has been reacted with dimethylglyoxime (DMG) in THF to form the PVC–DMG comples, which has been characterized by spectroscopic and elemental analyses. The latter indicate that there is one DMG moiety anchored on the PVC chain by displacing every 12th Cl atom in the chain. PVC–DMG has further been reacted with alcoholic solutions of Co(II), Ni(II), and Cu(II) to form the intensely colored PVC–DMG–M(II) complexes. The structures of these complexes have been analyzed by elemental and IR spectral analyses. The overall thermal stability of PVC–DMG–M(II) increases in the order: PVC < PVC–DMG–Cu(II) < PVC–DMG–Ni(II) < PVC–DMG–Co(II). The electrical conductivities are also significantly enhanced in the same order. The permittivities of these complexes are high relative to PVC at low frequency falling gradually with increasing frequency and the dielectric loss-frequency behavior is very broad.     

SEARCH FOH OPTIMUM CONDITIONS OF EXTRACTION OF METAL COMPLEXES WITH ALKYLIMIDAZOLES. III. STRUCTURE - EXTRACTABILITY RELATIONSHIPS FOR 1,4-DIMETHYLIMIDAZOLE COMPLEXES OF Co(II), Ni(II), Cu(II), Zn(II), AND Cd(II)

Stability constants of the 1,4-dimethylimidazole complexes of Co(II),Ni{II),Cu(II),Zn(II), and Cd(II) have been determined in aqueous solution and their structure has been elucidated. Conformational equilibria of the type octahedron-tetrahedron have been found in the case of the Co(II) and Sn(II) complexes. The extraction of all complexes has been shown to be dependent on their'molar contributions, d?n? expressed in per cent. The distribution constants have determined for each complex and the composition of the species extracted with organic solvent has been suggested.The measurements were run at 298?K, at the ionic strength of the aqueous phase of 0.5 maintained by means of KNO?3?.     

Antiandrogen and Antimicrobial Aspects of Coordination Compounds of Palladium(II), Platinum(II) and Lead(II)

Synthesis, characterization and antimicrobial activities of an interesting class of biologically potent macrocyclic complexes have been carried out. All the complexes have been evaluated for their antimicrobial effects on different species of pathogenic fungi and bacteria. The testicular sperm density, testicular sperm morphology, sperm motility, density of cauda epididymal spermatozoa and fertility in mating trails and biochemical parameters of reproductive organs have been examined and discussed. The resulting biologically active [M(MaL(n))(R(2))]Cl(2) and [Pb(MaL(n))(R(2))X(2)] (where, M = Pd(II) or Pt(II) and X = Cl or NO(3)) type of complexes have been synthesized by the reactions of macrocyclic ligands (MaL(n)) with metal salts and different diamines in 1:1:1 molar ratio in methanol. Initially the complexes were characterized by elemental analyses, molecular weight determinations and conductivity measurements. The mode of bonding was established on the basis of IR, (1)H NMR, (13)C NMR, (195)Pt NMR, (207)Pb NMR, XRD and electronic spectral studies. The macrocyclic ligand coordinates through the four azomethine nitrogen atoms which are bridged by benzil moieties. IR spectra suggest that the pyridine nitrogen is not coordinating. The palladium and platinum complexes exhibit tetracoordinated square-planar geometry, whereas a hexacoordinated octahedral geometry is suggested for lead complexes.     

Hydrothermal synthesis and structural characterization of one-dimensional coordination polymers of cobalt(II) and nickel(II) with 1,3,5-benzenetriacetic acid

Transition metal complexes [M(Hbta)(H₂O)₄] [M=Co(II) (1), Ni(II) (2), H₃bta=1,3,5-benzenetriacetic acid] have been prepared by reaction of H₃bta with the M(OH)₂ in water by hydrothermal method. The complexes were characterized by X-ray crystallography and electrospray mass spectrometry. The coordination geometries around Co(II) and Ni(II) atoms are both distorted octahedral with O₆ donor set. And the conformation of flexible triacid is cis, trans, trans in the title complexes.     

Conductometric studies of Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) tetrafluoroborates in N,N—dimethylacetamide solutions

Results are reported for the molar conductivities at 25°C of N,N—dimethylacetamide (DMA) solutions of Bu₄NBF₄ and Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) tetrafluoroborates. The limiting molar conductivities of [M(DMA)₆]²⁺ (M  MN, Co, Ni, Cu, Zn) and BF^?₄, as well as association constants for Co(BF₄)₂ in DMA solutions have been calculated. The slight differences between conductometric curves of different metal ions are discussed.     

Search for Optimum Conditions of Extraction of Transition Metal Complexes with Alkylimidazoles. I. Extraction of the Co(II), Ni(II), and Zn(II) Complexes of 1-Methylimidazole and of the Co(II) and Zn(II) Complexes of 2-Methylimidazole

Abstract

It has been shown that for the Co(II), Zn(II), and Ni(II) complexes of 1-methylimidazole and for the Co(II) and Zn(II) complexes of 2-methylimidazole, the partition coefficient D between the aqueous and organic phases is proportional to the degree of formation α _n of a definite complex. Tetrahedral species have been found to be extracted with the Co(II) and Zn(II) complexes of 2-methylimidazole and with the Zn(II) complexes of 1-methylimidazole.     

Synthesis and characterization of alumina-supported Mn(II), Co(II), Ni(II) and Cu(II) complexes of bis(salicylaldiminato)hydrazone as catalysts for oxidation of cyclohexene with tert-buthylhydroperoxide

Complexes of type [M(SAH)(OH₂)], where M is Mn(II),Co(II),Ni(II) and Cu(II), and SAH is the Schiff-base formed by condensation of salicylaldehyde (2 equiv.) and hydrazine (1 equiv.), bis(salicylaldiminato)hydrazone, or “2-({(z)-2-[(E)-1-(2-hydroxyphenyl)methylidene]hydrazono}methyl)phenol” have been prepared and characterized by elemental analysis, IR, UV–vis spectroscopy, conductometric, small area X-ray photoelectron spectroscopy and magnetic measurements. Elemental analysis suggests the stoichiometry to be 1:1 (metal:ligand). The results indicate that the Schiff-base ligand coordinates through one azomethine nitrogen and two phenolic oxygen to the metal ions. Conductance measurements suggest the non-electrolytic nature of the complexes. The atomic concentration of the complexes showed the ratio of M:N:O = 1:2:3, that indicates that a water molecule was in the complex. Alumina-supported complexes “[M(SAH)OH₂]-Al₂O₃” catalyze the oxidation of cyclohexene with tert-butylhydroperoxide (TBHP). The major products of the reaction were 2-cyclohexene-1-ol, 2-cyclohexene-1-one and 2-cyclohexene-1-(tert-butylperoxy). The influence of solvent on the oxidation reaction has been studied. [M(SAH)OH₂]-Al₂O₃ shows significantly higher catalytic activity than other alumina-supported complexes. These catalysts can also be reused in the oxidation of cyclohexene several times. The new materials “[M(SAH)OH₂]-Al₂O₃” were characterized by several techniques: chemical analysis and spectroscopic methods (FT-IR, UV–vis, XRD, DRS).     

SOLVENT EXTRACTION OF METALS WITH 4-DINITROBENZOYL-2, 4-DIHYDRO-5-METHYL-2-PHENYL-3H-PYRAZOL-3-ONE (DMPP)

ABSTRACT

The mechanism of the extraction of copper (II), nickel (II), cobalt (II) and thorium (IV) from aqueous buffer media with 4-dinitrobenzoyl1-2, 4-dihydro-5-methyl-2-phenyl-311-pyrazol-3-one (DMPP) in benzene has been investigated. The values of log K^*where K^*refers to the extraction equilibrium Mn⁺+-nHL ? MD_n+ nH⁺are Cu(II)& lpar; + 0.3), Co(II) (?6.65), Ni(II) (?5.04) and Th(IV) ( + 6.1). Solid complexes synthesized have the composition CuL₂· 2H₂O, NiL₂· 2H₂O and ThL₄respectively (L = anion of the ligand). DMPP seems to be superior to the corresponding 4-benzoyland 4-nitrobenzoyl derivatives of 2,4-dihydro-5-methyl-2-phenyl1-3 H-pyrazol1-3-one (MPP) and also better than thenoyltrifluoroacetone, the popularly employed fluorinated β-dike tone in the system investigated.     

Complexes With Biologically Active Ligands. Part 7 Synthesis and Fungitoxic Activity of Metal Complexes Containing 1,3,5-tris-(8-Hydroxyquinolino)- Trichlorocyclo-Triphosphazatriene

Complexes containing 1,3,5-tris-(8-hydroxyquinolino)-trichlorocyclotriphosphazatriene, a new cyclophosphazene ligand, and Co(II), Cu(II) and Ni(II) were prepared. The new complexes, having the general formula [MLCl(2)], [ML(2)]Cl(2), (M=Cu, Co, Ni); [NiLAc], [NiL(2)Ac]Ac and [ML(3)]X(3) (M=Ni, Co, X=Cl, Ac) were characterised by elemental analysis, electronic-, IR spectroscopy, and electrical conductivity measurements. Some of them inhibited the growth of several fungi species (Aspergillus and Candida spp.).     

Synthesis and Catalytic Activities of Silica-Supported Multifunctional Azo-Containing Schiff Base Complexes with Cu(II), Co(II), Ni(II) and Mn(II)

A novel 4-((5-formyl-2,4-dihydroxyphenyl)diazenyl)benzylphosphonic acid (FPABP) ligand was synthesized and bound to silica-gel which was activated with 3-aminopropyltriethoxysilane (APTES). Cu(II), Co(II), Ni(II) and Mn(II) complexes of silica-supported ligand (FDPDABP) were synthesized. The ligand and its complexes were characterized by using NMR, FT-IR, elemental analysis, ICP-OES and scanning electron Microscope (SEM). Catalytic properties of the complexes were investigated for the selective oxidation of cyclohexane under microwave power. SiO₂-FDPDABP-Cu(II) complex showed good catalytic activitiy for the selective oxidation of cyclohexane to cyclohexanol with 35.61% yield and cyclohexanone with 7.74% yield.     

Synthesis, Characterisation and Anti-Fungal Activities of Some New Copper(II) Complexes of Octamethyl Tetraaza-Cyclotetradecadiene

The ligand Me(8)[14]diene, L, in its free state as well as in the dihydroperchlorate form, L.2HClO(4), coordinates copper(ll) in different salts to yield a series of [CuLX(x)] X(y)(H(2)O)(z) complexes where X = NO(3), ClO(4), NCS, Cl and Br; x and y may have values of 0 or 2 and z = 0, 1 or 2. The complex, [CuL(ClO(4))(2)].2H(2)O is found to undergo axial ligand substitution reactions with SCN(-), NO(3) and Cl(-) to give a variety of substitution derivatives: [CuL(ClO(4))(m) X(n)] where X = NCS, NO(3) and Cl; m = 0 or 1, and n = 1 or 2. The complexes .have been characterised on the basis of analytical, spectroscopic, magnetic and conductance data. The anti-fungal activities of the ligand and its complexes have been investigated against a range of phytopathogenic fungi.