Arene ruthenium(II) p-chloroacetophenone phenylthiosemicarbazone complex mediated transfer hydrogenation of ketones

A series of cationic half-sandwich arene ruthenium(II) complexes of general formula [Ru(η6-p-cymene)Cl(L)]Cl have been synthesized from the reaction of [Ru(η6-p-cymene)Cl2]2 with thiosemicarbazone derivatives (L). Characterization of the complexes were accomplished by analytical and spectral (FT-IR, UV–Vis, 1H NMR) methods. Single crystal structure determination reveals the presence of a pseudooctahedral three-legged piano stool conformation. All the complexes exhibit a quasi-reversible one electron reduction in the range from −0.75 to −0.85 V. Further, the catalytic activity of the titled complex has been investigated in the transfer hydrogenation of ketones in the presence of isopropanol/NaOH.

Graphical abstractThe η6-p-cymene ruthenium(II)phenylthiosemicarbazone complexes were synthesized and characterized. One of the complexes [Ru(η6-p-cymene)Cl(L2)]Cl efficiently catalyzes the transfer hydrogenation of various ketones up to 99% conversion.Figure optionsDownload full-size imageDownload as PowerPoint slide