Synthesis, Characterization and Antimicrobial Investigation of Mixed Ligand Complexes of Cobalt(II) and Nickel(II) with P-Dimethylaminobenzaldehyde Thiosemicarbazone

A series of cobalt(II) and nickel(II) complexes were prepared by reactionswith p-dimethylaminobenzaldehydethiosemicarbazone (Hdmbtsc) in stoichiometric ratio of 1:2 and in the presence of co-ligandspyridine,1,10phenanthroline and PPh3, whichyieldedoctahedralcomplexes(1-8).The ligandactedasuninegative and neutral bidentateligandscoordinating through its N,S donor atoms. Dimethylaminobenzaldehyde thiosemicarbazone (Hdmbtsc)is reported to form complexes with mercury and zinc[14].The ligand andcomplexeswere characterized using spectroscopic techniques (UV-Vis,FTIR).Theywere screenedfor antibacterial activity against Gram +ve (Listeria) and Gram –ve (E.coli) bacteria and antifungal activityagainst Candida albicansusing agar diffusion method.Cobalt complexes 1,2and4and nickelcomplex 8were found to be active againstGram -ve bacteria (E.coli),while cobalt complexes1-5andnickel complex 6showed 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) werefound to be the most effective against tested bacterial and fungal strains.