Organotin(IV) complexes with pyruvic acid phenylhydrazone (HPAPD): synthesis, spectral characterization, and <i>in vitro</i> antibacterial activity

Abstract

The reaction of pyruvic acid phenylhydrazone [HPAPD, (1)] with organotin(IV) chloride(s) leads to the formation of five new organotin(IV) complexes: [MeSnCl2(PAPD)] (2), [BuSnCl2(PAPD)] (3), [PhSnCl2(PAPD)] (4), [Me2SnCl(PAPD)] (5), and [Ph2SnCl(PAPD)] (6). The ligand [HPAPD, (1)] and its organotin(IV) complexes (2–6) have been characterized by CHN analyses, molar conductivity, UV-Vis, FT-IR, 1H, 13C, and 119Sn NMR spectral studies. Spectroscopic data suggested that HPAPD is coordinated to tin(IV) through the carboxylato-O and azomethine-N as a mononegative bidentate chelating agent; the coordination number of tin is five. Compound 1 and its organotin(IV) complexes (2–6) were assayed for in vitro antibacterial activity against Staphylococcus aureus, Bacillus subtilis, Enterobacter aerogenes, Escherichia coli, and Salmonella typhi. The screening results show that 2–6 have better antibacterial activity than 1 and that 6 exhibits significantly better activity than 2–5.