Characterization of Ni(II) and Cd(II) Metal Complexes using Schiff Base Ligand derived from 2-Thiophenecarboxyldehyde and 2 Aminothiophenol

Schiff base ligand derived from condensation of 2-aminothiophenol and 2‑thiophenecarboxyldehyde was synthesized and used for the preparation of Ni(II) and Cd(II) complexes. The synthesized ligand and complexes were analyzed by decomposition temperature, solubility, magnetic susceptibility, molar conductance and infrared spectra. The decomposition temperatures of the complexes are 212 and 221°C. Molar conductance values are 16.12 and 12.60 ohm-1cm2mol-1 respectively. New bands appeared in the IR spectra of the complexes in the range of 519 - 475 cm-1 and 462 - 448 cm-1 which indicate υ (M - N) and υ (M - S) vibrations respectively. Magnetic susceptibility measurement indicated that Ni (II) complex is paramagnetic whileCd(II) complex is diamagnetic. The solubility test revealed that all complexes and ligand are soluble in DMSO. The analytical data show the formation of 2:1 metal to ligand ratio for all complexes and suggested the formula [ML2].nH2O. The ligand and metal chelates have been studied for microbial activity using well diffusion method against selected bacteria and fungi. The results signify that Ni(II) and Cd(II) metal complexes inhibit more compared with Schiff base ligand against the same test organisms.