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, H2L [where H2L = RC6H4NNC6H4NCH-C6H4OHR = p-H for H2L1, p-Me for H2L2 and p-Cl for H2L3], were prepared by the condensation of salicylaldehyde with 2-{(o-hydroxy aryl)azo} aniline. Reaction of H2L with VOSO4 afforded the oxovanadium complex, (L)V(O)(H2O). The (L1)V(O)(H2O) complex displays two reversible responses at 0.7 V and −0.65 V vs.SCE in cyclic voltammetry. Catalytic activity of (L1)V(O)(H2O) toward H2O2 induced oxidation of organic thioethers to sulfoxide and sulfones have been examined. The cytotoxicity of (L1)V(O)(H2O) has also been examined on human lung cancer cells.