Synthesis,characterization and biocidal activities of some metal(II) complexes with diacetyl salicylaldehyde acyldihydrazones

Complexes of diacetyl salicylaldehyde oxalic acid dihydrazone, CH₃COC(CH₃)= NNHCOCONHN=CHC₆H₄(OH),(dsodh) and diacetyl salicylaldehyde malonic acid dihydrazone CH₃COC(CH₃)=NNHCOCH₂CONHN=CHC₆H₄(OH), (dsmdh) of general compositions [M(L)]Cl, [M′(L)Cl], [M(L′)]Cl and [M′(L′)Cl] (where M?=?Co(II), Cu(II), Zn(II), Cd(II) and M′?=?Ni(II); HL?=?dsodh and HL′?=?dsmdh) were prepared and characterized by elemental analyses, molar conductance, magnetic moments, electronic, ESR and infrared spectra and X-ray diffraction data. The magnetic moments and electronic spectra indicate six-coordinate octahedral geometry for Co(II) and square planar geometry for Ni(II) complexes. The ESR spectral data of Cu(II) complexes in DMF solution reveal a tetragonally distorted octahedral geometry. Both ligands bond through >C=O, >C=N and deprotonated phenolate groups in all octahedral complexes and through >C=N and deprotonated phenolate groups in Ni(II) square planar complexes. The lattice parameters for Cu(dsodh) and Co(dsmdh) correspond to an orthorhombic and Ni(dsodh) corresponds to a tetragonal crystal lattice.

The complexes show significant antifungal activity against a number of pathogenic fungi viz. Stemphylium, Myrothecium and Alternaria. The antibacterial activity was studied against Pseudomonas fluorescence (gram ?ve) and Clostridium thermocellum (gram +ve).     

Synthesis and Structural Studies on Homo-and Heterobinuclear Complexes of Cu(II), Ni(II) and Co(II) with Arylideneanthranilic Acid Schiff Bases

Homo and heterobinuclear complexes of arylidene- anthranilic acids with Cu(II), Ni(II) and Co(II) are prepared and characterised by chemical analysis, spectral and X-ray diffraction techniques as well as conductivity measurements. Two types of homo-binuclear complexes are formed. The first has the formula M₂L₂Cl₂(H₂O)_n where M=Cu(II), Ni(II) and Co(II), L = p-hydroxybenzylideneanthranilic acid (hba), p-dimethylaminobenzylideneanthranilic acid (daba) and p-nitrobenzylideneanthranilic acid(nba) and n = 0–3. The second type has the formula M₂LCl₃(H₂O)_n in which M is the same as in the first type, L = benzylideneanthranilic acid (ba), (daba) (in cases of Cu(II) and Ni(II)); and n = 1–5. Heterobinuclear complexes having the formula (MLCl₂H₂O) MCl₂(H₂O)_n are isolated by reaction of Cu(II) binary chelates with Ni(II) and/or Co(II) chlorides. These are also characterized and their structures are elucidated.     

Synthesis and spectral studies of new N2S2 and N2O2 Mannich base ligands and their metal complexes

New Mannich bases bis(thiosemicarbazide methyl) phosphinic acid H₃L¹ and bis(1-phenylsemicarbazide methyl) phosphinic acid H₃L² were synthesized from condensation of phosphinic acid and formaldehyde with thiosemicarbazide and 1-phenylsemicarbazide, respectively. Monomeric complexes of these ligands, of general formula K₂[Cr^III(L ⁿ )Cl₂], K₃[Fe^II(L¹)Cl₂], K₃[Mn^II(L²)Cl₂], and K[M(L ⁿ )] (M = Co(II), Ni(II), Cu(II), Zn(II) or Cd(II); n = 1, 2) are reported. The mode of bonding and overall geometry of the complexes were determined through IR, UV-Vis, NMR, and mass spectral studies, magnetic moment measurements, elemental analysis, metal content, and conductance. These studies revealed octahedral geometries for the Cr(III), Mn(II), and Fe(II) complexes, square planar for Co(II), Ni(II), and Cu(II) complexes and tetrahedral for the Zn(II) and Cd(II) complexes. Complex formation via molar ratio in DMF solution has been investigated and results were consistent to those found in the solid complexes with a ratio of (M : L) as (1 : 1).     

Preparation and spectral characterization of new macrocyclic Ni(II) and Co(II) complexes derived from 1,4- bis (2-carboxyaldehydephenoxy)butane and various diamines

Six new macrocyclic complexes were synthesized by the template effect from reaction of 1,4-bis(2-carboxyaldehydephenoxy)butane, Ni(NO₃)₂ · 6H₂O or Co(NO₃)₂ · 6H₂O and various diamines. The metal-to-ligand ratios of Ni(II) or Co(II) metal complexes were found to be 1 : 1. Coordination of the Schiff base to Ni(II) and Co(II) through the two nitrogen and two oxygen atom (ONNO) are expected to reduce the electron density in the azomethine link and hydroxyl group. The Ni(II) and Co(II) complexes are proposed to be tetrahedral and are 1 : 2 electrolytes as shown by their molar conductivities (Λ_M) in DMF (dimethyl formamide) at 10^?3 M. The structures are proposed from elemental analysis, FT-IR, UV-VIS, magnetic susceptibility measurements, molar conductivity measurements, and mass spectra.     

Synthesis and physico-chemical studies of metal(II) complexes with diacetyl benzaldehyde acyldihydrazones and their bio-activity

Complexes of Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) with diacetyl benzaldehyde oxalic acid dihydrazone (dbodh), CH₃COC(CH₃)=NNHCOCONHN=CHC₆H₅ and diacetyl benzaldehyde malonic acid dihydrazone (dbmdh), CH₃COC(CH₃)=NNHCOCH₂CONHN=CHC₆H₅ of general composition [M(dbodh)Cl]Cl and [M(dbmdh)Cl]Cl were synthesized and characterized by microanalyses, molar conductance, magnetic susceptibility, UV–Vis, ESR and IR spectra and X-ray diffraction studies. The complexes are 1 : 1 electrolytes in DMF and are insoluble in water and common organic solvents. The dbodh and dbmdh are neutral tridentate ligands in most complexes and coordinate via one >C=O and two >C=N–groups. In Cu(II) complexes the ligands are pentadentate coordinating through three >C=O and two >C=N–groups. The magnetic moment values and UV–Vis spectra suggest square-planar geometry for Co(II) and Ni(II) complexes and distorted octahedron for both Cu(II) complexes. The ESR spectra of Cu(II) complexes show well-defined copper hyperfine lines in DMSO solution at 120 K and exhibit d _{x ² ?y ²} as the ground state. The X-ray diffraction parameters for [Ni(dbodh)Cl]Cl and [Co(dbmdh)Cl]Cl correspond to a tetragonal crystal lattice. The complexes show significant antifungal activity against Alternaria sp., Curvularia sp. and Colletotrichum sp. and fair antibacterial activity against Bacillus subtilis and Pseudomonas fluorescence.     

New homoleptic metal complexes of Schiff bases derived from 2,4-di-p-tolyl-3-azabicyclo[3.3.1]nonan-9-one

New bidentate Schiff-base ligands 2-(2,4-di-p-tolyl-3-azabicyclo[3.3.1]nonan-9-ylidene)hydrazinecarbothioamide HL¹ and 2-(2,4-di-p-tolyl-3-azabicyclo[3.3.1]nonan-9-ylidene)hydrazinecarboxamide HL² were synthesized from the condensation of 2,4-di-p-tolyl-3-azabicyclo[3.3.1]nonan-9-one with thiosemicarbazide and semicarbazide, respectively. Homoleptic complexes of these ligands, of general formula K[Cr(L ⁿ )₂Cl₂], K₂[Mn(L ⁿ )₂Cl₂], K₂[Fe(L¹)₂Cl₂] and [M(L ⁿ )₂] (where M = Co(II), Ni(II) Cu(II), Zn(II), Cd(II), and Hg(II) ions; n = 1 or 2) are reported. The mode of bonding and overall geometry of the complexes were determined through IR, UV-Vis, NMR and mass spectral studies, magnetic moment measurements, elemental analysis, metal content, and conductance. These studies revealed octahedral geometry for Cr(III), Mn(II), and Fe(II) complexes, square planar for Cu(II), Co(II), and Ni(II) complexes and tetrahedral for Zn(II), Cd(II), and Hg(II) complexes.     

Thermal Decomposition Kinetics of Some Metal Complexes of N,N-diethyl-n '-benzoylthiourea

Thermogravimetry (TG) and differential thermal analysis (DTA) were performed on the complexes with general formula (M(DEBT)_n (where M =Fe, Co, Ni, Cu or Ru; n =2, or 3 and DEBT=N,N-diethyl-N'-benzoylthiourea). Derivative thermogravimetric (DTG) curves were also recorded in order to obtain decomposition data on the complexes. The complexes of Fe(III), Co(II), Ni(II), Cu(II) and Ru(III) displayed two- or three-stage decomposition patterns when heated in a dynamic nitrogen atmosphere. Mass loss considerations relating to the decomposition stages indicated the conversion of the complexes to the sulfides or to the corresponding metal alone (Cu, Ru, NiS, CoS or FeS). Mathematical analysis of the TG and DTG data showed that the order of reaction varied between 0.395 and 0.973. Kinetic parameters such as the decomposition energy, the entropy of activation and the pre-exponential factor are reported. This revised version was published online in July 2006 with corrections to the Cover Date.     

Synthesis,crystal structure and DFT calculations of octahedral nickel(II) complexes derived from N′-[(E)-phenyl(pyridin-2-yl)methylidene]benzohydrazide

The two new nickel(II) complexes, [Ni(HL)(L)](NO₃)?H₂O (1) and [Ni(L)₂] (2) (where HL/L = N′-[(E)-phenyl(pyridin-2-yl)methylidene]benzohydrazide), have been synthesized and characterized by elemental analysis, spectroscopic, magnetic susceptibility, and cyclic voltammetric measurements. Single-crystal X-ray analysis of [Ni(HL)(L)](NO₃)?H₂O (1) and [Ni(L)₂] (2) has revealed the presence of a distorted octahedral geometry around nickel(II). The X-ray and spectral characterizations have confirmed the existence of the keto-enol form of the ligands in the complexes. The electronic structures and spectral properties of the ligands and the complexes have been explained by DFT and TDDFT calculations. Superoxide dismutase activity of these complexes has also been measured.     

Novel 2-aminoimidazole-4-one complexes of copper(II) and cobalt(II): Synthesis,structural characterization and cytotoxicity

A series of 2-aminosubstituted (5Z)-3-phenyl-5-(pyridine-2-ylmethylene)-3,5-dihydro-4H-imidazole-4-ones (L) was prepared by the reaction of the corresponding 2-alkylthio-3,5-dihydro-4H-imidazole-4-ones with morpholine or piperidine in the presence of ytterbium(III) triflate. The resulting ligands were subsequently reacted with CuCl₂·2H₂O and CoCl₂·6H₂O to give the corresponding copper(II) and cobalt(II) complexes, respectively. Analysis revealed that the complexes were formed with an LMCl₂ (M = Cu, Co)-type composition in all cases. The structures of the three cobalt complexes prepared in this way were determined by X-ray crystallography. The results revealed that the cobalt ions in these complexes were tetrahedrally coordinated to two chloride anions and two nitrogen atoms from the pyridine and imidazole moieties of the ligand. The electrochemical properties of the ligands and their complexes were evaluated by cyclic voltammetry, and the results revealed that the first stage in the reduction of the Co(II) and Cu(II) complexes involved the reversible formation of the corresponding Co(I) and Cu(I) complexes, respectively. The cytotoxicity activities of the organic ligands and their complexes were evaluated against several cancer cell lines, including MCF-7, A549 and HEK293 cells. The copper complexes of the organic ligands bearing a phenyl or allyl moiety at their N(3) position together with a piperidine substituent at the 2-position of their imidazolone ring exhibited the greatest cytotoxicity of all of the compounds tested in the current study.     

Synthesis and spectroscopic studies of novel transition metal complexes with schiff base synthesized from 1,4-bis-(<Emphasis Type="Italic">o</Emphasis>-aminophenoxy)butane and salicyldehyde

The new Co(II), Cu(II), Ni(II) and Zn(II) complexes of potentially N₂O₂ Schiff base ligand [N,N’-bis(salicyldehydene)-1,4-bis-(o-aminophenoxy)butane] (H₂L) prepared from 1,4-bis-(o-aminophenoxy)butane and salicyldehyde in DMF. Microanalytical data, elemental analysis, magnetic measurements, ^lH NMR, ¹³C NMR, UV-visible and IR spectra as well as conductance measurements were used to confirm the structures. In all complexes, H₂L behaves as a tetradentate. The article is published in the original.     

Synthesis and Structural Studies of 2,2′-[(2E,5E)-hexane-2,5-diylidenedi-nitrilo]-dibenzenethiol and 2-Hydroxybenzaldehyde (2E,5E)-hexane-2,5-diylidenehydrazone ligands and their Mononuclear Cu(II) and Ni(II) Complexes

Monomeric copper(II) and nickel(II) complexes with tetradentate two new ligands, 2,2′-[(2E,5E)-hexane-2,5-diylidenedi- nitrilo]dibenzenethiol(H₂L) and 2-hydroxybenzaldehyde (2E,5E)-hexane-2,5-diylidenehydrazone(H₂L¹) have been synthesized and characterized by elemental analyses, magnetic moments, molar conductance, ¹H-NMR and ¹³C-NMR, IR, mass spectral studies, theoretical calculations (MM2 and AM1) molecular methods. The mononuclear metal complexes of H₂L and (H₂L¹) were found to have a 1:1 metal:ligand ratio. Elemental analyses, stoichiometric and spectroscopic data of metal complexes indicated that the metal ions were coordinated to the sulphur (-SH) and/or (-OH) oxygen and imine nitrogen atoms (C = N). All of the data obtained from spectral, and molecular mechanics (MM2) or semi empirical calculations (AM1) studies support the structural properties of ligands and its Cu(II) and Ni(II) metal complexes.     

The synthesis and characterization of three new vic -dioximes and their nickel(II), copper(II) and cobalt(II) complexes

Three new vic-dioximes, [L¹H₂], N-(4-ethylphenyl)amino-1-acetyl-1-cyclohexenylglyoxime, [L²H₂], N-(4-butylphenyl)amino-1-acetyl-1-cyclohexenylglyoxime, and [L³H₂], N-(4-methoxyphenyl)amino-1-acetyl-1-cyclohexenylglyoxime were synthesized from 1-acetyl-1-cyclohexeneglyoxime and the corresponding substituted aromatic amines. Metal complexes of these ligands were also synthesized with Ni(II), Cu(II), and Co(II) salts. These new compounds (ligands and complexes) were characterized with FT–IR, magnetic susceptibility measurement, molar conductivity measurements, mass spectrometry measurements, thermal methods (e.g. thermal gravimetric analysis), ¹H NMR (Nuclear Magnetic Resonance) and ¹³C NMR spectral data and elemental analyses.     

Metal complexes of azo coumarin derivative: synthesis,spectroscopic, thermal,and antimicrobial studies

Cu(II), Co(II), Ni(II), Cd(II), and Zn(II) complexes of 6-(2-phenyldiazenyl)-7-hydroxy-4-methyl coumarin (PAHC) are characterized based on elemental analyses, infrared, ¹H NMR, magnetic moment, molar conductance, mass spectra, UV-Vis analysis, thermogravimetric analysis (TGA), and X-ray powder diffraction. From the elemental analyses, it is found that the complexes have formulae [M(L)₂(H₂O) _n ] ? xH₂O (where M = Cu(II), Co(II), Ni(II), Cd(II), and Zn(II), n = 0–2, x = 1–4). The molar conductance data reveal that all the metal chelates are non-electrolytes. From the magnetic and solid reflectance spectra, it is found that the structures of these complexes are octahedral or tetrahedral. The synthesized ligand and metal complexes were screened for antibacterial activity against some Gram-positive and Gram-negative bacteria.     

Coordination compounds of Co(II), Ni(II) and Cu(II) with capric acid hydrazide

The reaction of aquo-ethanolic solutions of Co(II), Ni(II) and Cu(II) salts and ethanolic solution of capric acid hydrazide (L) yielded paramagnetic, high-spin bis- and tris(ligand) chelate complexes. The tris(ligand) complexes, [ML ₃]X ₂·nH₂O [M=Co(II), Ni(II);X=NO ₃ ^– , ClO ₄ ^– , 1/2SO ₄ ^2– ], have an octahedral structure formed on account of the bidentate (NO) coordination of three neutral hydrazide molecules. In the bis(ligand) complexes,ML ₂(NCS)₂ [M=Co(II), Ni(II)] and CuL ₂ X ₂·nH₂O (X=NO ₃ ^– , ClO ₄ ^– and 1/2SO ₄ ^2– ), the oxoanions and NCS^– take also part in coordination. The complexes have been characterized by elemental analysis, IR spectra, magnetic measurements, molar conductivity and TG analysis.

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Caprinsäurehydrazid-Komplexe von Co(II), Ni(II) und Cu(II)

Zusammenfassung Durch die Reaktion von wäßrig-ethanolischen Lösungen von Co(II)-, Ni(II)-und Cu(II)-Salzen mit einer ethanolischen Lösung von Caprinsäurehydrazid (L) wurden paramagnetische high-spin Bis- und Tris-Ligand-Chelatkomplexe erhalten. Tris-Ligand-Komplexe des Typs [ML ₃ X ₂·nH₂O [M=Co(II), Ni(II);X=NO ₃ ^– , ClO ₄ ^– , 1/2SO ₄ ^2– ], die eine oktaedrische Struktur besitzen, entstehen durch die Koordination von drei neutralen zweizähnigen (NO)-Hydrazidmolekülen. Bei den Bis-Ligand-KomplexenML ₂(NCS)₂ [M=Co(II), Ni(II)], sowie bei den Bis-Ligand-Komplexen CuL ₂ X ₂·nH₂O (X=NO ₃ ^– , ClO ₄ ^– , 1/2SO ₄ ^2– ) nehmen bei der Koordination außer Hydrazid auch die Säurereste teil. Die Komplexe wurden durch Elementaranalyse, IR-Spektren, magnetische Messungen, molare Leitfähigkeit und TG-Analysen charakterisiert.

     

Characterization of Copper(II), nickel(II), cobalt(II) and palladium(II) complexes of vicinal oxime-imine ligands; induced chelate isomerism in the same molecule of the nickel(II) complex

Summary Metal complexes of the title ligands were characterized in order to determine the factors influencing the stability of chelate isomerism in the same molecule. The ligands were prepared by 1:1 condensation of isonitrosoacetylacetone (Hiso) with eithero-aminophenol (H₂ isoaph),p-aminophenol (H₂ isopph), or aniline (Hisoanil). The following complexes have been synthesized: [(isoaph)Cu]₄, (Hisoaph)₂Co, (Hisopph)₂ M·nH₂O (M=Ni(II), n=2;M=Pd(II), n=0;M=Co(II), n=2), [(isopph) Cu·H₂O]₂, and (isoanil)₂ M (M=Ni(II), Cu(II), Co(II), or Pd(II)). Both chelate rings in these metal complexes are five-membered. Transimination of one –C=N–C₆H₅ group to –C=NH in (isoanil)₂Ni produced a six-membered chelate ring in (isoim)Ni(isoanil). The induced chelate isomerism is ascribed to intermolecular hydrogen bonding of the imino-hydrogen and the basic nitrogen of the same six-membered chelate ring of an adjacent square planar molecule. Other types of hydrogen bondings with the oximato oxygen (intra- or intermolecular) favour the formation of five-membered chelate rings. Analytical, spectroscopic, and magnetic moment data are in accordance with the suggested formulations.Part of the Ph.D. thesis of Sana M. Imam     

Synthesis,characterization and antimicrobial activity of a new macrocycle and its transition metal complexes

The semicarbazone (L¹) has been prepared by reaction of semicarbazide and glutaraldehyde (2 : 1) in distilled water and methanol (1 : 1). The reaction of semicarbazide, glutaraldehyde and diethyl oxalate in distilled water and methanol gave Schiff-base L², 1,2,4,7,9,10-hexaazacyclo-pentadeca-10,15-dien-3,5,6,8-tetraone. Complexes of first row transition metal ions Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) have also been synthesized. The ligand and its complexes were characterized by elemental analysis, molar conductance, magnetic moment measurements, IR, ¹H NMR, UV–Visible spectra and thermogravimetric analysis (TGA). Molar conductance values show that the complexes of Ni(II), Cu(II), Zn(II), Mn(II) and Co(II) are 1 : 2 electrolytes. On the basis of electronic spectral studies and molar conductance measurements an octahedral structure has been proposed for Mn(II) and Co(II) complexes, tetrahedral for Zn(II) complex and square planar for Ni(II) and Cu(II). The thermal behavior of the compounds, studied by TGA in a nitrogen atmosphere up to 800°C, reveal that the complexes have higher thermal stability than the macrocycle. All the synthesized compounds and standard drugs kanamycin (antibacterial) and miconazole (antifungal) have been screened against bacterial strains Staphylococcus areus, Escherichia coli and fungal strains Candida albicans, Aspergillus niger. The metal complexes inhibit growth of bacteria to a greater extent than the ligand.     

Synthesis,characterization and antimicrobial studies of novel ONO donor hydrazone Schiff base complexes with some divalent metal (II) ions

Metal complexes of two general formulae [M(L)(Cl)(H₂O)₂] [M = Mn(II), Co(II), Ni(II) and Cu(II)] and [M(L)(H₂O)] [M = Zn(II) and Cd(II)] with pyrazine-2-carbohydrazone of 2-hydroxy-5-methylacetophenone (H₂L) are synthesized and characterized by microanalytical, thermal, magnetic susceptibility measurement, spectroscopic (IR, ¹H NMR, ¹³C NMR), mass, molar conductance, X-ray powder diffraction, ESR and SEM studies. While the molar conductance measurements in DMSO indicated their non-electrolytic nature, the spectroscopic studies confirmed a tridentate ONO donor behaviour of the ligand towards the central metal ion. Based on the physico-chemical studies monomeric octahedral geometry around Mn(II), Co(II), Ni(II) and Cu(II) ions (i.e. for the first series of complexes) whereas tetrahedral to Zn(II) and Cd(II) ions (i.e. for the second series of complexes) are suggested. Based on the thermal behavior of the complexes, various kinetic and thermodynamic parameters were evaluated using Coats-Redfern method. The ligand and its metal complexes were screened for in vitro antibacterial and antifungal activity against Gram +ve S. aureus, B. subtilis and Gram –ve E. coli and S. typhi. and fungal strains, C. albicans and A. niger. The observed data infer promising biological activity of some of these complexes compared the parent ligand against all bacterial and fungal species.     

Synthesis,structural studies and bio-activity of Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) complexes with p -amino acetophenone salicyloyl hydrazone

Complexes of the type [M(pash)Cl] and [M(Hpash)(H₂O)SO₄] (M=Mn(II), Co(II), Ni(II), Cu(II) and Zn(II); Hpash = p-amino acetophenone salicyloyl hydrazone) have been synthesized and characterized by elemental analyses, molar electrical conductance, magnetic moments, electronic, ESR and IR spectra, thermal studies and X-ray powder diffraction. All the complexes are insoluble in common organic solvents and are non-electrolytes. The magnetic moment values and electronic spectra indicate a square-planar geometry for Co(II), Ni(II) and Cu(II) chloride complexes and spin-free octahedral geometry for the sulfato complexes. The ligand coordinates through >C=N–,–NH₂ and a deprotonated enolate group in all the chloro complexes, and through >C=N–, >C=O and–NH₂ in the sulfato complexes. Thermal analyses (TGA and DTA) of [Cu(pash)Cl] show a multi-step exothermic decomposition pattern. ESR spectral parameters of Cu(II) complexes in solid state at room temperature suggest the presence of the unpaired electron in d _{x ² ? y ²} . X-ray powder diffraction parameters for [Cu(pash)Cl] and [Ni(Hpash)(H₂O)SO₄] correspond to tetragonal and orthorhombic crystal lattices, respectively. The complexes show a fair degree of antifungal activity against Aspergillus sp., Stemphylium sp. and Trichoderma sp. and moderate antibacterial activity against E. coli and Clostridium sp.     

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

Two bidentate Schiff bases, 5-methyl-2-p-tolyl-4-(1-p-tolylimino-propyl)-2H-pyrazol-3-ol (L1) and 2-(3-chloro-phenyl)-5-methyl-4-(1-p-tolylimino-propyl)-2H-pyrazol-3-ol (L2), were synthesized by condensation of 4-acyl pyrazolones with p-toluidine in ethanol. These ligands have been characterized by elemental analysis, infrared (IR), ¹H NMR, and mass spectra. A single crystal molecular structure of ligand L2 was also solved. Nickel(II) complexes of these ligands with general formula [ML₂?·?2H₂O] have been prepared by the interaction of aqueous solution of Ni-acetate with ethanolic solution of the appropriate ligand. The complexes were separated, analyzed, and their structures were elucidated on the basis of elemental analysis, Ni(II) determination, IR, UV-Vis, conductance, mass, and TGA-DTA data. Octahedral structure was proposed for the synthesized complexes.     

Preparation,IR Characterization and Thermal Properties of Some Metal Complexes of Isatin-3-oxime

The synthesis and characterization of Co(II), Ni(II), Cu(II), Zn(II), Ag(I), Cd(II) and Hg(II) complexes of isatin-3-oxime (H₂OXI) are reported. Elemental analysis, infrared spectroscopy, thermal analysis and X-ray powder diffraction were used to characterize the complexes. The IR spectral data show that the ligand behaves in a monodentate or a bidentate manner in the different complexes. The compositions of the prepared complexes were Ag(HOXI), Hg(OXI) and M(HOXI)₂ for M=Co(II), Ni(II), Cu(II), Zn(II) and Cd(II).This revised version was published online in November 2005 with corrections to the Cover Date.