First 3,5-diacetyl-1,2,4-triazol derived mono(thiosemicarbazone) and its palladium and platinum complexes: Synthesis, structure and biological properties

•The first mono(thiosemicarbazone) ligand based on 3,5-diacetyl-1,2,4-triazol diketone.•Pd and Pt complexes show [NNS,P] chelation.•The free ligand exhibits the highest cytotoxicity against the tumor cell lines tested.•DNA binding ability of the new ligand was explored by UV–Vis absorption spectroscopy.

Preparation and characterization of 3,5-diacetyl-1,2,4-triazol mono(4-phenylthiosemicarbazone) ligand, H3L, and its derived palladium(II) and platinum(II) complexes, [Pd(HL)(PPh3)] and [Pt(HL)(PPh3)], 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 [N2SP] 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 cytotoxicity of the new compounds synthesized was investigated in vitro against T-47D, A2780 and A2780cisR human cancer cell lines, being H3L the species with the highest activity. In addition, the DNA binding ability of H3L with calf thymus DNA was explored by UV–Vis absorption spectroscopy.

Graphical abstractThe first mono(thiosemicarbazone) ligand based on 3,5-diacetyl-1,2,4-triazol and its Pd(II) and Pt(II) derivatives have been synthesized and characterized. The cytotoxicity of the new compounds synthesized was investigated in vitro against T-47D, A2780 and A2780cisR human cancer cell lines, being H3L the species with the highest activity. In addition, the DNA binding ability of free ligand with CT-DNA was explored by UV–Vis absorption spectroscopy.Figure optionsDownload full-size imageDownload as PowerPoint slide