Abstrakt

Synthesis and thermal studies on new Co(II), Ni(II), Cu(II) and Cd(II) mixed ligand complexes with 3-benzyl-4-amino-1,2,4-triazole-5-thione Schiff bases and ,-bipyridyl

Dina Mamdouh Fouad, Ahmed Bayoumi, Mohamed Abd El-Hakim El-Gahami, Said Ahmed Ibrahim, Abbas Mohamed Hammam

New octahedral mixed ligand complexes of cobalt(II), nickel(II), copper(II) and cadmium(II) have been synthesized with neutral bidentate N, S donor ligands such as 3-benzyl-1H -4-[(2-methoxybenzylidine)amino]-1,2,4- triazole-5-thione(MBT) , 3-benzyl-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 ,-bipyridyl(bipy)which coordinate to themetal atom through two nitrogen atoms. The synthesized complexes have been characterized by elemental analyses, spectroscopicmeasurements (IR, UV-Vis.),molar conductance,magneticmeasurements and thermal studies. The stoichiometry of thesemixed ligand complexes ismetal ion: L1: L2=1:1:1, 1:2:1 or 1:1:2; L1=NBT,MBT orCBT and L2=8-hydroxyquinoline. The thermal decomposition study of the prepared mixed ligand complexes was monitored by TG, DTG and DTAanalysis in dynamic nitrogen atmosphere. TG, DTG and DTAstudies confirmed the chemical formulations of theses complexes. The kinetic parameters were determined fromthe thermal decomposition data using the graphical methods of Coats-Redfern and Horwitz-Metzger. Thermodynamic parameters were calculated using standard relations. NBT was found to formthe most stable Cu(II) and Ni(II) mixed ligand complexes whileMBT forms themost stable Co(II) and Cd(II)mixed ligand complexes.