Interaction of ruthenium(II) and ruthenium(III) ions with 5-methyl-1,2,4-triazolo[1,5-a]pyrimidin-7(4H)-one

Abstract

Ru(II) and Ru(III) complexes with 5-methyl-1,2,4-triazolo[1,5-a]pyrimidin-7(4H)-one (HmtpO) of the formula cis-[RuCl2(dmso)3(HmtpO)] (1) and trans-[RuCl4(dmso)(H2mtpO)]·4H2O (2) have been synthesized and characterized using different spectroscopic techniques (IR, 1H–15N HMBC, 1H–13C HSQC, 1H–13C HMBC and EPR). Spectroscopic studies reveal a monodentate coordination of the heterocycle ligand (HmtpO) via N3 to the ruthenium(II) and ruthenium(III) ions. In addition, the X-ray crystal structure was determined for complex (2). The compound crystallized in the triclinic group P1¯. The asymmetric unit of the structure consists of two complex molecules (2a and 2b) and 8 water molecules. The equatorial positions are occupied by four chloride ions, while the N3 bonded, protonated H2mtpO+ and S-bonded dmso ligands are located in axial positions. Complex (1) has been screened for in vitro cytotoxicity against two human cells: non-small cell lung carcinoma (A549) and breast cancer (T47D). The ruthenium(II) complex was found to be less active than cisplatinum.