Keywords: Dimethylaminobenzaldehyde thiosemicarbazone; UV-Vis.spectra; antibacterial, antifungal activity, octahedral complexes

Abstract

A series of cobalt(II) and nickel(II) complexes were prepared by reactions with p-dimethylaminobenzaldehyde thiosemicarbazone (Hdmbtsc) in stoichiometric ratio of 1:2 and in the presence of co-ligands pyridine, 1,10 phenanthroline and PPh3, which yielded octahedral complexes (1-8). The ligand acted as uninegative and neutral bidentate ligands coordinating through its N, S donor atoms. Dimethylaminobenzaldehyde thiosemicarbazone (Hdmbtsc) is reported to form complexes with mercury and zinc [14]. The ligand and complexes were characterized using spectroscopic techniques (UV-Vis, FTIR). They were screened for antibacterial activity against Gram +ve (Listeria) and Gram –ve (E. coli) bacteria and antifungal activity against Candida albicans using agar diffusion method. Cobalt complexes 1, 2 and 4 and nickel complex 8 were found to be active against Gram -ve bacteria (E. coli), while cobalt complexes 1-5 and nickel complex 6 showed moderate activity against fungi (Candida albicans). [Co(dmtsc)2(phen)]Cl2 (4), [Co(dmtsc)2(PPh3)2(NO3)2] (5) and [Ni(Hdmtsc)2(Cl)2] (6) were found to be the most effective against tested bacterial and fungal strains.