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

Three structurally different mononuclear dichlorido platinum(II) complexes with 5,7-diethyl-1,2,4triazolo[1,5-a]pyrimidine (detp) were synthesized and characterized through multinuclear magnetic resonance (H-1, C-13, N-15, Pt-195) 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. (C) 2016 Elsevier B.V. All rights reserved.