A NOVEL SERIES OF PALLADIUM(II) AND PLATINUM(II) COMPLEXES WITH 1,4-BENZODIAZEPINES AS LIGANDS

Abstract

The complexing behaviour towards palladium(II) and platinum(II) halides of some 1,4-benzodiazepines is reported. The ligands used in this study are 7-chloro-2-methylamino-5-phenyl-3H-1,4-benzodiazepin-4-oxide, 1,3-dihydro-7-nitro-5-phenyl-2H-1,4-benzodiazepin-2-one and 7-chloro-1-methyl-5-phenyl-3H-1,4-benzodiazepin-2-one. The complexes have been studied by means of magnetic susceptibility measurements, infrared and far infrared spectra, electronic spectra and conductivity measurements. The most convincing structural evidence for these complexes is a square planar stereochemistry with bridging ligands joining two metal ions and terminal halides in the 1:1 complexes and terminal ligands and terminal halides in the 1:2 derivatives. Assignments for the metal-ligand and metal-halide bands have also been made.     

Bis -(3,5-dimethyl-pyrazolyl-1-methyl)-(3-phosphanyl-propyl)-amine complexes of copper(II), nickel(II), and cobalt(II)

A series of Cu(II), Co(II), and Ni(II) complexes of bis-(3,5-dimethyl-pyrazolyl-1-methyl)-(3-phosphanyl-propyl)-amine C₁₅H₂₆N₅P (1), prepared from 3-aminopropylphosphine and 1-hydroxymethyl-3,5-dimethylpyrazole were characterized. The nature of bonding and the geometry of the complexes have been deduced from elemental analysis, infrared, electronic, ¹H NMR, ³¹P NMR spectra, magnetic susceptibility, and conductivity measurements. The studies indicate octahedral geometry for nickel complex and square pyramidal geometry for copper and cobalt complexes. The EPR spectra of copper complex in acetonitrile at 300 K and 77 K were recorded. Biological activities of the ligand and metal complexes have been studied on Staphylococcus aureus, Escherichia coli, Aspergillus niger, and Aspergillus flavus by well-diffusion method. The zone of inhibition values were measured at 37°C for a period of 24 h. The electrochemical behavior of copper complexes was studied by cyclic voltammetry. Catalytic study indicates the copper complex has efficient catalytic activity in oxidation of amitriptyline.     

Studies on mononuclear chelates derived from substituted Schiff-base ligands (part 6): synthesis and characterization of a new 3-ethoxysalicyliden- p -aminoacetophenoneoxime and its complexes with cobalt(II), nickel(II), copper(II) and zinc(II)

Schiff-base complexes of cobalt(II), nickel(II), copper(II) and, zinc(II) with 3-ethoxysalicyliden-p-aminoacetophenoneoxime (HL) were prepared and characterized on the basis of elemental analyses, IR, ¹H- and ¹³C-NMR, electronic spectra, magnetic susceptibility measurements, molar conductivity and thermogravimetric analyses (TGA). A tetrahedral geometry has been assigned to the complexes.     

A NEW CYCLOBUTANE SUBSTITUTED SCHIFF BASE LIGAND,SYNTHESIS OF ITS Cd(II), Co(II), Cu(II), Ni(II) AND Zn(II) COMPLEXES AND INVESTIGATION OF THEIR STRUCTURE

Abstract

A new, thiazole derivative ligand, 4-(1-phenyl-1-methylcyclobutane-3-yl)-2-(2-hydroxy-5-bromo benzylidenehydrazino) thiazole (LH), has been synthesized by the reaction of 2-hydroxy-5-bromobenzaldehyde, thiosemicarbazide and subsequently 1-phenyl-1-methyl-3-(2-chloro-1-oxoethyl) cyclobutane. Mononuclear complexes with a metal-ligand ratio of 1 : 2 have been prepared with Cd(II), Co(II), Cu(II), Ni(II) and Zn(II). The authenticity of the ligand and its complexes was established by elemental analyses, IR, ¹³C and ¹H NMR spectra, magnetic susceptibility measurements and thermogravimetric analyses (TGA) and differential scanning calorimetry (DSC).     

Syntheses and spectroscopic studies on group IIB metal 1,4-benzodiazepine complexes

Summary The preparation and characterization of some zinc(II) and cadmium(II) halide complexes with 1,3-dihydro-7-nitro-5-phenyl-2H-1,4-benzodiazepin-2-one and 7-chloro-l-methyl-5-phenyl-3H-1,4-benzodiazepin-2-one are reported. The complexes have been studied by means of magnetic susceptibility measurements, i.r. and far-i.r. spectra and conductivity measurements. Assignments for metalligand and metal-halide modes have been made. The evidence suggests that the complexes, which contain 1 : 1.5, 1 : 1, 1 : 2 and 1 : 4 metal : ligand stoichiometric ratios, have a pseudotetrahedral symmetry, with the exception of Zn(Mog)₄Br₂ ·₂H₂O which is octahedral.     

Copper(II), nickel(II), cobalt(II) and zinc(II) complexes of 2-[2-(6-methylbenzothiazolyl)azo]-5-dimethylaminobenzoic acid: synthesis,spectral, thermal and molecular modelling studies

Complexes of copper(II), nickel(II), cobalt(II), and zinc(II) with 2-[2-(6-methylbenzothiazolyl)azo]-5-dimethylaminobenzoic acid have been prepared and characterized by elemental analysis, vibrational spectra, magnetic susceptibility measurements, conductance measurements and e.p.r. spectra. Stability constants have been evaluated potentiometrically. Electronic spectra, magnetic susceptibility measurements and molecular modeling studies support a distorted square planar geometry around the metal ions. Vibrational spectra indicate the coordination of the azo group, nitrogen of benzothiazole, the carboxylate anion and the acetate ion on complexation with the metal ion. All complexes are found to be monomers. The stability of the complexes follow the order: copper(II) > nickel(II) > cobalt(II) > zinc(II).     

Synthesis and characterization of iron(III), manganese(II), cobalt(II), nickel(II), copper(II) and zinc(II) complexes of salicylidene-N-anilinoacetohydrazone (H2L1) and 2-hydroxy-1-naphthylidene-N-anilinoacetohydrazone (H2L2)

Salicylidene-N-anilinoacetohydrazone (H(2)L(1)) and 2-hydroxy-1-naphthylidene-N-anilinoacetohydrazone (H(2)L(2)) and their iron(III), manganese(II), cobalt(II), nickel(II), copper(II) and zinc(II) complexes have been synthesized and characterized by IR, electronic spectra, molar conductivities, magnetic susceptibilities and ESR. Mononuclear complexes are formed with molar ratios of 1:1, 1:2 and 1:3 (M:L). The IR studies reveal various modes of chelation. The electronic absorption spectra and magnetic susceptibility measurements show that the iron(III), nickel(II) and cobalt(II) complexes of H(2)L(1) have octahedral geometry. While the cobalt(II) complexes of H(2)L(2) were separated as tetrahedral structure. The copper(II) complexes have square planar stereochemistry. The ESR parameters of the copper(II) complexes at room temperature were calculated. The g values for copper(II) complexes proved that the Cu-O and Cu-N bonds are of high covalency.     

Local structure analysis of Cu(II)-diazepam complexes by ESR spectroscopy

CuL(2)X(2) (L = 7-chloro-1,3-dihydro-1-methyl-5-phenyl-3H-1,4-benzodiazepin-2-one, also known as diazepam, X = Cl, Br) complexes have been prepared and investigated by ESR spectroscopy. Powder ESR spectra of these complexes suggest a planar-rhombic distorted local symmetry. The CH(3)Cl solutions spectra show the presence of pseudo-tetrahedral species with a 3d(xy)+4p(z) mixture ground state for the paramagnetic electron. The anisotropic spectra obtained for the Cu(II)-diazepam solution adsorbed on NaY zeolite confirm the existence of a CuN(2)X(2) chromophore.     

Synthesis and spectroscopic studies of copper(II) and nickel(II) complexes containing hydrazonic ligands and heterocyclic coligand

Two types of copper(II) and nickel(II) complexes derived from benzophenone anthranoylhydrazone (L1), 2-acetonaftanone anthranoylhydrazone (L2), 4-phenylacetonaftonone anthranoylhydrazone (L3), benzophenone salicyoylhydrazone (L4), 2-acetonaftanon salicyoylhydrazone (L5), 4-phenylacetonaftanon salicyoylhydrazone (L6) and bidentate heterocyclic base [1,10-phenanthroline (phen)] with general stoichiometry [ML2] and [ML(phen)]Cl have been synthesized and characterized by elemental analysis, infrared spectra, UV-vis electronic absorption spectra and magnetic susceptibility measurements. The effect of varying pH and solvent on the absorption behavior of both ligands and complexes have been investigated. According to the IR spectra, the ligands act as monobasic bidentate and coordination takes place in the enol tautomeric form.     

Local structure analysis of Cu(II)-diazepam complexes by ESR spectroscopy

CuL₂X₂ (L = 7-chloro-1,3-dihydro-1-methyl-5-phenyl-3H-1,4-benzodiazepin-2-one, also known as diazepam, X = Cl, Br) complexes have been prepared and investigated by ESR spectroscopy. Powder ESR spectra of these complexes suggest a planar-rhombic distorted local symmetry. The CH₃Cl solutions spectra show the presence of pseudo-tetrahedral species with a 3d_xy+4p_z mixture ground state for the paramagnetic electron. The anisotropic spectra obtained for the Cu(II)-diazepam solution adsorbed on NaY zeolite confirm the existence of a CuN₂X₂ chromophore.     

Iron(II), cobalt(II), nickel(II) and copper(II) chelates of 1,1′-Dibenzoylacetylferrocene

Summary 1,1-Dibenzoylacetylferrocene (DBAFc) complexes of iron(II), cobalt(II), nickel(II) and copper(II) have been prepared and characterized. The physical properties of the complexes are discussed on the basis of uv-visible, Mössbauer spectra and magnetic measurements.     

Iron(II), cobalt(III), nickel(II) and copper(II) chelates of furan and thiophene azo-oximes

Summary Complexes of furan and thiophene azo-oximes with iron(II), cobalt(III), nickel(II) and copper(II) have been prepared and characterised. Iron(II), cobalt(III) and copper(II) complexes are diamagnetic in the solid state. The diamagnetism of the copper(II) chelates is suggestive of antiferromagnetic interaction between two copper centres.¹H n.m.r. spectral data suggest atrans-octahedral geometry for the tris-chelates of cobalt(III). Nickel(II) complexes are paramagnetic, in contrast to the diamagnetism of the analogous complexes of arylazooximes. The electronic spectra are suggestive of octahedral geometry for the iron(II), cobalt(III) and nickel(II) complexes, andD _4h -symmetry for copper(II). Infrared data indicate N-bonding of the oximino-group to the metal ions.     

Nickel(II) and copper(II) complexes of 5-substituted-salicylaldehyde thiosemicarbazones

Binuclear nickel(II) and copper(II) complexes with four 5-methoxysalicylaldehyde N(3)-substituted thiosemicarbazones and nickel(II) complexes of four 5-nitro-salicylaldehyde N(3)-substituted thiosemicarbazones have been prepared and characterized. I.r., electronic, and e.s.r. spectra of the complexes, as well as i.r., electronic, and 1H- and 13C-n.m.r spectra of the thiosemicarbazones, have been obtained. None of these compounds show significant growth inhibitory activity against the fungi Aspergillus niger and Paecilomyces variotii.     

Spectral studies on cobalt(II), nickel(II) and copper(II) complexes of naphthaldehyde substituted aroylhydrazones

A series of new coordination complexes of cobalt(II), nickel(II) and copper(II) with two new aroylhydrazones, 2-hydroxy-1-naphthaldehyde isonicotinoylhydrazone (H(2)L(1)) and 2-hydroxy-1-naphthaldehyde-2-thenoyl-hydrazone (H(2)L(2)) have been synthesized and characterized by elemental analysis, conductance measurements, magnetic susceptibility measurements, (1)H NMR spectroscopy, IR spectroscopy, electronic spectroscopy, EPR spectroscopy and thermal analysis. IR spectra suggests ligands acts as a tridentate dibasic donor coordinating through the deprotonated naphtholic oxygen atom, azomethine nitrogen atom and enolic oxygen atom. EPR and ligand field spectra suggests octahedral geometry for Co(II) and Ni(II) complexes and a square planar geometry for Cu(II) complexes.     

Copper(II) coordination compounds with 2-(7-bromo-2-oxo-5-phenyl-3<Emphasis Type="Italic">H</Emphasis>-1,4-benzdiazepin-1-yl)acetohydrazide and products of its condensation with pyruvic acid

Some methods for the synthesis of copper(II) complexes with 2-(7-bromo-2-oxo-5-phenyl-3H-1,4-benzodiazepin-1-yl)acetohydrazide (Hydr) ([Cu(Hydr)(H₂O)Cl₂]) and products of its condensation with pyruvic acid ([Cu(HydrHPv)(H₂O)Cl₂] and, with alkalization to pH 8, [Cu(HydrPv)₂]) were developed, and the complexes themselves were synthesized. The complexes were characterized by electrical conductivity, magnetic susceptibility, and IR and EPR spectroscopy measurements.     

4-Cyanoaniline complexes with transition metal(II) halides

Summary Coordination compounds formed by the interaction of manganese(II), cobalt(II), nickel(II) and copper(II) chloride and bromide with 4-cyanoaniline (4-CA) have been prepared and characterized by molar conductance, magnetic susceptibilities, electronic and i.r. spectral measurements down to 200 cm^–1 in the solid state. The isolated complexes are M(4-CA)₂X₂ except for nickel(II) bromide which is NI(4-CA)₄Br₂. I.r. spectra, indicate that 4-CA, though a potentially bidentate ligand, nevertheless acts only as a terminally aniline (NH₂) bonded monodentate ligand in all the complexes. Tentative stereochemistries of the complexes have been suggested in the solid state.     

Copper(II), nickel(II) and cobalt(II) complexes of oxaldihydrazide and succindihydrazide Schiff bases with salicylaldehyde ando-hydroxyacetophenone

Summary Polymeric copper(II), nickel(II) and cobalt(II) complexes of the type M₂L where M = Cu^II, Ni^II or Co^II and H₄L = disalicylaldimine oxamide (H₄A), di(o-hydroxyacetophenoneimine)oxamide (H₄B), disalicylaldimine succinamide (H₄C) or di(o-hydroxyacetophenoneimine)succinamide (H₄D), have been synthesized and characterized by analysis, i.r. and electronic spectra and magnetic moment data. Copper(II) complexes and some of the nickel(II) and cobalt(II) complexes are planar while other nickel(II) complexes are distorted octahedral and other cobalt(H) complexes are square pyramidal. Anomalously low magnetic moments of some complexes have been related to M-M interactionsvia oxo-bridge structures.     

Physicochemical Investigation on the Complexes of Co(II), Ni(II) and Cu(II) with Aminocyclodiphosph(V)azane Derivative

Co(II), Ni(II), and Cu(II) form 2:1 complexes with aminocyclodiphosph(V)azane derivative. The complexes have been investigated in solution by the spectrophometric molar ratio and conductometeric methods. The ligand and its complexes have been isolated in solid state and characterized on the basis of microanalytical, infrared, electronic, magnetic moment, 1 H NMR and mass spectral data. The cobalt and nickel complexes were assigned to be in tetrahedral structure while the copper complex is assigned to be in square planar.     

Zinc(II), Cobalt(II) and Nickel(II) Complexes of 5-Substituted-1,3,4-Thiadiazoles

Zn(II), Co(II) and Ni(II) complexes with some 5-substituted-1,3,4-thiadiazoles (L₁-L₄) have been prepared and characterized by conductivity, microanalysis, thermal analysis, infrared and electronic spectra measurements. All complexes behave as 1:1 electrolyte and the ligands are coordinated as bidentate molecules. The stability constants and energy of formation are determined and discussed on the basis of the ligands structure.     

Thermal Studies of Cobalt(II), Nickel(II) and Copper(II) Complexes of 4-(Sulfonylazido Phenylazo) Pyrazolones

The thermal decompositions of cobalt(II), nickel(II) and copper(II) complexes of4-(3'-sulfonylazido-6'-methoxyphenylazo)-1-phenyl-3-methyl-2-pyrazolin-5-one H(D¹–SO₂N₃) and 4-(4'-sulfonylazido phenylazo)-3-phenyl-3-methyl-2-pyrazolin-5-one H(D²–SO₂N₃) were studied by thermogravimetry. The decomposition in all cases takes place along two stages. The first stage is due to the elimination of water and nitrogen molecules with the formation of tetracoordinate complexes containing nitrene reactive species[M(DSO₂N:)₂]. The second stage represents the decomposition of the material to the metal oxide. The kinetics of the decomposition were examined by using Coats–Redfern, the decomposition in all complexes was found to be first order for the first and second stages. The activation energies and other activation parameters (H^* and S^* and G^*) were computed and related to the bonding and stereochemistry of the complexes.This revised version was published online in November 2005 with corrections to the Cover Date.