Synthesis, structure and reactivity of azosalophen complexes of vanadium(IV): studies on cytotoxic properties.

The free ligands, 2-{(o-hydroxyaryl)azo}-1-N-salicylidene phenylamine, H(2)L [where H(2)L = RC(6)H(4)N=NC(6)H(4)N=CH-C(6)H(4)OHR = p-H for H(2)L(1), p-Me for H(2)L(2) and p-Cl for H(2)L(3)], were prepared by the condensation of salicylaldehyde with 2-{(o-hydroxy aryl)azo} aniline. Reaction of H(2)L with VOSO(4) afforded the oxovanadium complex, (L)V(O)(H(2)O). The (L(1))V(O)(H(2)O) complex displays two reversible responses at 0.7 V and -0.65 V vs. SCE in cyclic voltammetry. Catalytic activity of (L(1))V(O)(H(2)O) toward H(2)O(2) induced oxidation of organic thioethers to sulfoxide and sulfones have been examined. The cytotoxicity of (L(1))V(O)(H(2)O) has also been examined on human lung cancer cells.