Synthesis, structural characterization, thermal and electrochemical studies of Mn(II), Co(II), Ni(II) and Cu(II) complexes containing thiazolylazo ligands (original) (raw)
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Spectrochimica Acta Part A-molecular and Biomolecular Spectroscopy, 2009
Some mixed ligand Cu(II) complexes of the type [Cu( L)( en)X 2] ( 1a-3a), [Cu( L)( en)](ClO 4) 2 ( 4a), [Cu( L)( phen)X 2] ( 1b-3b) and [Cu( L)( phen)](ClO 4) 2 ( 4b) [where L = 2-phenyl-3-(benzylamino)-1,2-dihydroquinazoline-4-(3H)-one; en = ethylenediamine; phen = 1,10-phenanthroline; X = Cl -, N 3- and NCS -] have been prepared. The complexes were characterized on the basis of elemental analysis, molar conductance, magnetic moment, IR, UV-vis, mass, ESR and thermal studies. On the basis of electronic spectral data and magnetic susceptibility measurement octahedral geometry has been proposed for 1a-3a and 1b-3b and square-planer geometry for 4a and 4b. The ESR spectral data of complexes provided information about their structure on the basis of Hamiltonian parameters and degree of covalency. The electrochemical behaviour of mixed ligand Cu(II) complexes was studied which showed that complexes of phen appear at more positive potential as compared to those for corresponding en complexes.
Spectrochimica Acta Part A-molecular and Biomolecular Spectroscopy, 2009
Some mixed ligand complexes of the type [M(L 1 or L 2 )(phen or en)(H 2 O)Cl], where M = Mn(II), Co(II), Ni(II) and Cu(II); HL 1 = 2-mercapto-quinazolin-4-one; HL 2 = 2-mercapto-3-phenyl-quinazolin-4-one; phen = 1,10-phenanthroline; en = ethylenediamine have been prepared. All complexes were characterized on the basis of elemental analysis, molar conductance, magnetic susceptibility measurements, IR, UV-vis, ESR and powder X-ray diffraction studies. IR spectra of these complexes reveal that the complex formation occurred through both nitrogen and sulphur atoms. On the basis of electronic spectral data and magnetic susceptibility measurement octahedral geometry has been proposed for the complexes. The ESR spectral data of the Cu(II) complexes showed that the metal-ligand bonds have considerable covalent character. X-ray diffraction studies of Cu(II) complexes are used to elucidate the crystal structure. The electrochemical behaviour of mixed ligand Ni(II) complexes was studied which showed that complexes of phen appear at more positive potential as compared to those for corresponding en complexes.
Russian Chemical Bulletin, 2005
New transition metal (NiII, CoII, and CuII) complexes with 2-methylthio-5-(pyridyl-methylidene)-3,5-dihydro-4H-imidazol-4-ones were synthesized by the reaction of 5-(α-, β-, or γ-)pyridyl-substituted 2-methylthio-3,5-dihydro-4H-imidazol-4-ones with MCl2· nH2O. In the complexes with α-Py-substituted ligands, the metal atom has a tetrahedral coordination environment and is coordinated by the nitrogen atoms of the pyridine and thiohydantoin rings and two chloride anions. The results of electronic spectroscopy and magnetic susceptibility measurements suggest that the complexes with the β-and γ-Py-substituted ligands have polymeric structures, and the metal atoms in these complexes are in an octahedral environment. The molecular and crystal structures of CuIIL1Cl2 (L1 is (5Z)-2-methylthio-3-phenyl-5-(α-pyridylmethylidene)-3,5-dihydro-4H-imidazol-4-one) and CoIIL2Cl2 (L2 is (5Z)-3-methyl-2-methylthio-5-(α-pyridylmethylidene)-3,5-dihydro-4H-imidazol-4-one) were established by X-ray diffraction. Semiempirical quantum-chemical calculations were performed for 2-methylthio-5-(pyridylmethylidene)-3,5-dihydro-4H-imidazol-4-ones. The complexes, starting ligands, and metal chlorides were studied electrochemically. The mechanism of electro-oxidation and electroreduction of 2-methylthio-5-(pyridylmethylidene)-3,5-dihydro-4H-imidazol-4-ones and their cobalt, nickel, and copper complexes was proposed.
Preparation and characterization of some transition metal complexes Co(II},Ni(II),Cu(II)
isara solutions, 2015
A new series of transtion metal complexes of Co(II},Ni(II),Cu(II),Zn(II},Cd(lI) and Hg(lI) were prepared from the novelazo-schiff base ligand (BIADPI) from by coupling reaction of benzimidazolediazonium chloride with 3-(benzylideneimino)phenoI. They have been characterized by elemental analsis (C.H.N),magnetic susceptibility molar conductance and spectral techniques such us FT-IR/H-NMR,electronic spectra and mass spectrometry. The spectral studies of the comlexesreval that the azo-schiff base as a tridentate ligand coordination through the deprotonated phenolic oxygen ,N3 of benzimidazole ring and N3 of azo group which is the farthest of benzimidazole molecule.
Natural Science, 2010
A series of new mixed ligand complexes of cobalt(II), nickel(II), copper(II) and cadmium(II) have been synthesized with 3-benzyl-1H-4-[(2methoxybenzylidine) amino]-1, 2, 4-triazole-5thione (MBT), 3-bezyl-1H-4-[(4-chlorobenzylidine) amino]-1, 2, 4-triazole-5-thione (CBT), 3-benzyl-1H-4-[(4-nitrobenzylidine)amino]-1, 2, 4-triazole-5-thione (NBT) and dehydroacetic acid sodium salt (Nadha). The mixed ligand complexes have been characterized by elemental analysis, spectroscopic spectral measurements (IR, UV-Vis.), molar conductance, magnetic measurements and thermal studies. The stoichiometry of these complexes is M:L 1 :L 2 = 1:1:1, 1:2:1 or 1:1:2 where L 1 = NBT, CBT and MBT and L 2 = Nadha. Tetrahedral structure was proposed for all Cd(II) mixed ligand complexes while the square planar geometry was proposed for Cu(II) mixed ligand complex with NBT. Octahedral structure was proposed for Ni(II), Co(II) mixed ligand complexes and Cu(II) mixed ligand complexes with CBT and MBT ligands. The thermal decomposition study of the prepared complexes was monitored by TG, DTG and DTA analysis in dynamic nitrogen atmosphere. TG, DTG and DTA studies confirmed the chemical formulations of theses complexes. The kinetic parameters were determined from the the thermal decomposition data using the graphical methods of Coats-Redfern and Horwitz-Metzger. Thermodynamic parameters were calculated using standard relations.
Baghdad Science Journal, 2022
This study describes the preparation of new series of tetra-dentate N2O2 dinuclear complexes (Cr3+, Co2+, Cu2+) of the Schiff base derived from condensation of 1-Hydroxy-naphthalene-2-carbaldehyde with 2-amino-5-(2-hydroxy-phenyl)-1,3,4-thiadiazole. The structures of the ligands were identified using IR, UV-Vis , mass, elemental analysis and 1H-NMR techniques. All prepared complexes have been characterized by conductance measurement, magnetic susceptibility, electronic spectra, infrared spectrum, theromgravimatric analysis (TGA) and metal analysis by atomic absorption. From stoichiometry of metal to ligand and all measurements show a octahedral geometry proposed for all complexes of the (Cr3+, Co2+, Cu2+). conductivity measurement shows that of the prepared (Co2+, Cu2+) complexes were non electrolyte but (Cr3+) complexes were electrolyte. The parameters of thermodynamic, activation energy Ea , enthalpy ΔH, entropy ΔS and Gibbs free energy ΔG were calculated using Coats-Redfern me...
Dalton Transactions, 2012
In order to understand and predict structural, redox, magnetic, and optical properties of more complex and potentially mesogenic electroactive compounds such as [Co III (L t-BuLC ) 2 ]ClO 4 (1), five archetypical complexes of general formula [Co III (L RA ) 2 ]ClO 4 , where R = H (2), tert-butyl (3), methoxy (4), nitro (5), and chloro , were obtained and studied by means of several spectrometric, spectroscopic, and electrochemical methods. The complexes 2, 4, and 6 were characterized by single-crystal X-ray diffraction, and show the metal center in an approximate D 2h symmetry. Experimental results support the fact that the electron donating or withdrawing nature of the phenolate-appended substituents changes dramatically the redox and spectroscopic properties of these compounds. The 3d 6 electronic configuration of the metal ion dominates the overall geometry adopted by these compounds with the phenolate rings occupying trans positions to one another. Formation of phenoxyl radicals has been observed for 1, 3, and 6, but irreversible ligand oxidation takes place upon bulk electrolysis. These data were compared to detailed B3LYP/6-31G (d)-level computational calculations and have been used to account for the results observed. A comparison between compound 1 and archetype 3, validates the approach of using archetypical models to study metal-containing soft materials.
New mixed ligand Complexes of Mn(II), Fe(II), Co(II), Ni(II),
A series of few mixed ligand complexes of, manganese(II),iron(II),cobalt(II), nickel(II), zinc (II) and cadmium(II), have been synthesized with The mixed ligand complexes have been characterized by, spectroscopic spectral measurements (FT-IR, U.V- Vis), molar conductance, magnetic measurements, and chloride content (Mohr Method) , metal contents of the complexes were determined by Atomic Absorption . The results suggest that the Mn(II), Fe(II), Co(II), Ni(II), Zn(II), and Cd(II) have distorted tetrahedral geometry . The following general formulae were proposed for the prepared complexes:[M (pro) (Thr)] , where pro- = C5H8NO2 - Thr= C4H9NO2 - , M+2 = Mn(II), Fe(II), Co(II), Ni(II), Zn(II), and Cd(II). Molar conductance of a 10−3M solution in (DMF) indicates that all the complexes are non-electrolytes.
Journal of Inorganic and Organometallic Polymers and Materials, 2009
Transition metal complexes of Mn(II), Fe(III), Cr(III) and Zn(II) metal ions with a general formulas [Mn(L) 2 (Cl) 2 ]Á4H 2 O (I), [Fe(L) 2 (Cl) 2 ]ÁClÁ6H 2 O (II), [Cr(L) 2 (Cl) 2 ]ÁClÁ6H 2 O (III) and [Zn(L) 2 (Cl) 2 ]Á2H 2 O (IV) where L = 4-acetylpyridine thiosemicarbazone, have been synthesized and interpreted using CHN elemental analysis, magnetic susceptibility measurements, molar conductance, thermal analysis and spectroscopic techniques; i.e., infrared, electronic UV/vis, 1 H-NMR and mass. The manganese(II), ferric(III), chromium(III) and zinc(II) complexes have octahedral geometry. The molar conductance measurements reveal that the Mn(II) and Zn(II) chelates are non-electrolytes but Fe(III) and Cr(III) have an electrolytic behavior. The IR spectra show that the 4-acetylpyridine thiosemicarbazone free ligand is coordinated to the metal(II) chlorides as a neutral bidentate ligand through both of the lone pair of electrons of the C=N azomethine group and C=S group. X-ray powder diffraction gives an impression that the resulting complexes are amorphous and different from the start materials. The thermogravimetric studies indicate that uncoordinated water molecules are lost in the first and second decomposition steps. The activation thermodynamic parameters E*, DH*, DS* and DG* are estimated from the differential thermogravimetric analysis (DTG) curves using Horowitz-Metzger (HM) and Coats-Redfern (CR) methods. The ligand and its complexes have been screened for antibacterial and antifungal activities against two bacteria; i.e., Escherichia coli (Gram-ve) and Bacillus subtilis (Gram ?ve) and two fungi, i.e., tricoderma and penicillium activities).
Cobalt(II), nickel(II) and copper(II) complexes of 5-(2-carboxyphenylazo)-2-thiohydantoin
Transition Metal Chemistry, 2003
A new series of hexacoordinate cobalt(II), nickel(II) and copper(II) complexes of 5-(2-carboxyphenylazo)-2-thiohydantoin HL having formulae [LM(OAc)(H2O)2] · nH2O (M = CoII, CuII and NiII), [LM′Cl(H2O)2] · nH2O (M′ = CoII and NiII), [LCuCl(H2O)]2 · 2H2O, [LCu(H2O)3](ClO4) and [LCu(HSO4)(H2O)2] were isolated and characterized by elemental analyses, molar conductivities and magnetic susceptibilities, and by i.r., electronic and e.s.r. spectral measurements, as well as by thermal (t.g. and d.t.g.) analyses. The i.r. spectra indicate that the ligand HL behaves as a monobasic tridentate towards the three divalent metal ions via an azo-N, carboxylate-O and thiohydantoin-O atom. The magnetic moments and electronic spectral data suggest an octahedral geometry for CoII complexes, distorted octahedral geometry for both NiII and CuII complexes with a dimeric structure for [LCuCl(H2O)]2 · 2H2O through bridged chloro ligands. The X-band e.s.r. spectra reveal an axial symmetry for the copper(II) complexes with unsymmetrical ΔMs = ± 1 signal and G-parameter less than four for the dimeric [LCuCl(H2O)]2 · 2H2O. The thermogravimetry (t.g. and d.t.g.) of some complexes were studied; the order and kinetic parameters of their thermal degradation were determined by applying Coats–Redfern method and discussed.