Metal complexes of 2-benzoylpyridine-derived thiosemicarbazones: structural, electrochemical and biological studies

Abstract

Complexes of 2-benzoylpyridine thiosemicarbazone (H2Bz4DH) as well as of its N(4)-methyl (H2Bz4Me) and N(4)-phenyl (H2Bz4Ph) analogues with iron(II), nickel(II) and zinc(II) were characterized by a variety of spectroscopic techniques. Electrochemical studies revealed that the iron(II) complexes undergo oxidation giving the iron(III) analogues, which could be reduced back by cellular thiols such as thioredoxine, suggesting that this process could occur in biological media. The thiosemicarbazones have antifungal activity against Candida albicans that significantly decreases on coordination. The crystal structure 2-benzoylpyridine-N(4)-methyl thiosemicarbazone (H2Bz4Me) was determined.