Synthesis, Electrochemical, Spectroscopic, Antimicrobial, and Superoxide Dismutase Activity of Nickel (II) Complexes with Bidentate Schiff Bases

Five new nickel (II) complexes, namely, [Ni(L1)2](ClO4)2(1); [Ni(L2)2](ClO4)2(2); [Ni(L3)2](ClO4)2(3); [Ni(L4)2](ClO4)2(4); [Ni(L5)2](ClO4)2(5), where L1 = benzoylhydrazide; L2 = N-[(1)-1-(2-methylphenyl)ethylidene]benzohydrazide; L3=N-[(1)-1-(4-methylphenyl)ethylidene]benzohydrazide; L4=N-[(1)-1-(2-methoxyphenyl)ethylidene]benzohydrazide; L5 = N-[(1)-1-(4-methoxy-phenyl)ethylidene]benzohydrazide, have been synthesized and characterized by various physicochemical and spectroscopic techniques. The synthesized complexes are stable powders, insoluble in common organic solvents such as ethanol, benzene, carbon tetrachloride, chloroform, and diethyl ether, and are nonelectrolytes. The magnetic and spectroscopic data indicate a distorted square planar geometry for all complexes. The superoxide dismutase activity of these complexes has been measured and discussed. Antibacterial and antifungal properties of these complexes were also tested.