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.