Synthesis, magnetic, spectral and antimicrobial activity of new Schiff bases complexes derived from 1,2,4-triazole-5-thione

A series of biologically active new mixed ligand complexes of cobalt(II), nickel(II) copper(II) and cadmium(II) have been synthesized. The reactions of the Schiff base ligand 3-benzyl-1H-4-[(2-methoxybenzylidine)amino]l,2,4-triazole-5-thione(MBT);3-benzyl-1H-4-[(4chlorobenzylidine)amino]-1,2,4-triazole-5-thione(CBT); 3benzyl-1H-4-[(4-nitrobenzylidine)amino]-1,2,4-triazole-5-thione (NBT) and sodium diethyldithiocarbamate trihydrate(dtc) as second ligand. The mixed ligand complexes have been characterized by elemental analyses, spectroscopic measurements (FT-IR, UV-Vis and ESR.), molar conductance, and magnetic measurements. The stoichiometry of these complexes is 1:1:1 ; 1:2:1or 1:1:2 (M:L1:L2). All mixed ligand complexes have octahedral structures. The free ligands and its their metal complexes were screened for their in vitro antibacterial activity against Gram-negative and Gram-positive bacterial strains and for in vitro antifungal activity. The results of these studies showed that the Cd (II) complexes have higher activity against bacteria and fungi than the free ligands and other metal complexes.