Synthesis, X-ray diffraction structure, spectroscopic properties and antiproliferative activity of a novel ruthenium complex with constitutional similarity to cisplatin

Abstract

The light-protected reaction of [(η6-p-cymene)Ru IICl2]2 with 1-(2-hydroxyethyl)piperazine in dry methanol, followed by addition of excess NH4PF6, afforded the complex [(η6-p-cymene)RuII(NH 3)2Cl](PF6) (1) in 47% yield. Attempts to use the same protocol for the synthesis of [(η6-p-cymene)Os II(NH3)2Cl](PF6) led to the isolation of the binuclear triply methoxido-bridged arene-osmium compound [{(η6-p-cymene)Os}2(μ-OCH3) 3](PF6) (3). Both compounds were characterised by X-ray crystallography and 1H NMR spectroscopy, and the ruthenium complex also by spectroscopic techniques (IR and UV-vis spectroscopies). The antiproliferative activity of complex 1in vitro was studied in A549 (non-small cell lung carcinoma), CH1 (ovarian carcinoma), and SW480 (colon carcinoma) cells and compared to that of [(η6-p-cymene)RuII(en)Cl] (PF6) (2). In contrast to the latter compound, 1 is only modestly cytotoxic in all three cell lines (IC50: 293-542 μM), probably due to the instability of the diammine ruthenium complex in aqueous solution. © 2009 The Royal Society of Chemistry.