Synthesis, characterization, anti-bacterial and anticancer activities of Palladium(II) mixed ligand complexes of 2-mercapto-5-methyl-1,3,4-thiadiazole (HmtzS) and phosphines. Crystal structure of [Pd(mtzS)2(dppf)].H2O.EtOH

Abstract

Two thione and thionate based complexes were synthesized by simply reacting the ligand 2-mercapto-5-methyl-1,3,4-thiadiazole (HmtzS) with palladium(II) salt in a neutral or basic medium in 2:1 molar ratio. Reacting of resulting complex [Pd(mtzS)2] (2) with Ph2P(CH2)nPPh2 (n = 1–4), dppf, Ph3P or Ph3PS yielded mononuclear complexes, [Pd(mtzS)2(Ph2P(CH2)nPPh2)] (3–5), [Pd(mtzS)2(dppf)] (6), [Pd(mtzS)2(Ph3P)2] (7) or [Pd(mtzS)2(Ph3PS)2] (8). An X-ray structure of [Pd(mtzS)2(dppf)] (6) shows that the mtzS ligand is now coordinated in a monodentate fashion via the sulfur atom.. The prepared complexes were screened against Pseudomonas aeruginosa, Bacillus subtilis, Staphylococcus aurous, Escherichia coli and S. typhi. Moreover the cytotoxicity of the prepared complexes were evaluated against colon mammalian cancer (LoVo) and breast cancer (MCF-7) cell lines by MTT assay. Results shows that complexes exhibited cytotoxicity with IC50 values within (9.7 ± 1.2) to (39.1 ± 7.6) µM range against LoVo and within (8.8 ± 1.4) to (40.2 ± 2.6) µM range against MCF-7 cell lines.