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

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-(CH2NHBu)-Bu-t), and C4H3NH(2-CH=NR) are separately coupled with [(eta(6)-cymene)RuCl2](2) (1) (cymene = 4-isopropyltoluene) to synthesize five Ru-derivatives: [(eta(6)-cymene)RuCl(kappa(2)-N,O-OOCCHNH2CH2CH2COOH)] (2), {(eta(6)-cymene) RuCl[C4H3N(2-(CH2NHBu)-Bu-t)]} (3), {(eta(6)-cymene) RuCl [C4H3N(2-CH=NCH2Ph)]} (4), {(eta(6)-cymene)RuCl{ C4H3N [2-CH=NCH2(C4H7O)]}} (5) and {(eta(6)-cymene) RuCl [C4H3N(2-(CHBuNHCH2)-Bu-n(C4H7O))]} (7). To the best of our knowledge, the aforementioned Ru compounds are not only characterized by H-1 and C-13 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.