Synthesis and characterization of a new bioactive mono(thiosemicarbazone) ligand based on 3,5-diacetyl-1,2,4-triazol diketone and its palladium and platinum complexes.

Preparation and characterization of a new 4 N - p -chlorophenyl substituted thiosemicarbazone ligand, H 3 L 2 , and its derived palladium(II) and platinum(II) complexes, [Pt(HL 2 )(PPh 3 )] and [Pd(HL 2 )(PPh 3 )], is described. The molecular structures of the two new metal complexes have been determined by single crystal X-ray diffraction. In both complexes the metal ion is four-coordinated with a [N 2 SP] donor environment, via one triazole nitrogen atom, the azomethine nitrogen and thione sulfur atoms of the thiosemicarbazone moiety and a phosphorous atom from the triphenylphosphine coligand. The biological activity of the new compounds synthesized was initially explored by determining their antiproliferative activity in vitro against T-47D, A2780 and A2780 cis R human cancer cell lines. The cytotoxicity data suggest that these compounds may be endowed with important antitumor properties, especially H 3 L 2 since is capable not only to circumvent cisplatin resistance in A2780 cis R cells but also to exhibit high antiproliferative activity in breast cancer T-47D cells. [ABSTRACT FROM AUTHOR]