Catalytic transfer hydrogenation and anticancer activity of arene-ruthenium compounds incorporating bi-dentate precursors

Abstract

Ruthenium based organometallic compounds are presently a subject of great attention as anticancer drugs and appear to work reasonably well on tumor cells. We develop a series of mononuclear arene-ruthenium compounds incorporating N,O and N,N bidentate ligands, and their activity as anticancer drugs against human hormone-refractory metastatic prostate cancer (HRMPCs) cell lines are investigated. The ruthenium compounds also act as effective catalysts in the transfer hydrogenation of the -C=O- → -CH(OH)- system. Three types of ligands, namely, sodium glutamate, C4H3NH(2-CH2NHtBu), and C4H3NH(2-CH=NR) are separately coupled with [(η6-cymene)RuCl2]2 (1) (cymene = 4-isopropyltoluene) to synthesize five Ru-derivatives: [(η6-cymene)RuCl(κ2-N,O-OOCCHNH2CH2CH2COOH)] (2), {(η6-cymene)RuCl[C4H3N(2-CH2NHtBu)]} (3), {(η6-cymene)RuCl[C4H3N(2-CH=NCH2Ph)]} (4), {(η6-cymene)RuCl{C4H3N[2-CH=NCH2(C4H7O)]}} (5) and {(η6-cymene)RuCl[C4H3N(2-CHnBuNHCH2(C4H7O))]} (7). To the best of our knowledge, the aforementioned Ru compounds are not only characterized by 1H and 13C NMR spectroscopy, but for the first time their structures have been established by single crystal X-ray diffractometry. Compound 4 influences a concentration-dependent apoptosis in PC-3 cells and initiates the conversion rate in transfer hydrogenation. ? The Royal Society of Chemistry.