Synthesis, characterization and in vitro cytotoxicity of three types of platinum(II) complexes containing 5,7-diethyl-1,2,4-triazolo[1,5-a]pyrimidine

Abstract

Three structurally different mononuclear dichlorido platinum(II) complexes with 5,7-diethyl-1,2,4-triazolo[1,5-a]pyrimidine (detp) were synthesized and characterized through multinuclear magnetic resonance (1H, 13C, 15N, 195Pt) and infrared spectroscopy. The X-ray structure of cis-[PtCl2(detp)(dmso)] (2) was determined using the single-crystal X-ray diffraction technique. The molecular structure of (2) exhibits a square planar geometry surrounding the Pt(II) ion with a unique placement of two chlorido ligands in the cis position in the presence of a S-dmso molecule in the coordination sphere.All NMR data obtained in solution unambiguously confirmed the square planar geometry of Pt(II) with monodentate N3-bonded detp, a monodentate second ligand (detp or NH3 or dmso) and two chlorido ligands in the cis geometry.Cytotoxicity tests using human carcinoma cell lines, specifically the T47D (breast cancer), A549 (non-small cell lung carcinoma), and LoVo (colon cancer) cell lines, and the healthy cell line BALB/3T3 (mouse embryonic fibroblast), indicated that only cis-[PtCl2(detp)2] (1) possesses similar in vitro cytotoxicity against T47D and sevenfold lower toxicity than cisplatin.