Half-sandwich ruthenium-based versatile catalyst for both alcohol oxidation and catalytic hydrogenation of carbonyl compounds in aqueous media

摘要

A series of half-sandwich ruthenium-based catalysts for both alcohol oxidation and carbonyl compounds hydrogenation have been synthesized through metal-induced C-H bond activation based on benzothiazole ligands. The neutral ruthenium complexes 1-4 were fully characterized by UV-vis, NMR, IR, and elemental analysis. Molecular structures of complexes 1 and 3 were further confirmed by X-ray diffraction analysis. All complexes exhibited high activity for the catalytic oxidation of a variety of alcohols with (BuOOH)-Bu-t as oxidants to give carbonyl compounds with high yields in water. Moreover, these half-sandwich complexes also showed high efficiency for the catalytic hydrogenation of carbonyl compounds in a methanol-water mixture. The catalyst could be reused for at least five cycles without any loss of activity. The catalytic system also worked well for various kinds of substrates with either electron-donating or electron-withdrawing groups.