Synthesis and characterization of half-sandwich ruthenium complexes containing aromatic sulfonamides bearing pyridinyl rings: catalysts for transfer hydrogenation of acetophenone derivatives

1099-0682N-(Quinoline-8-yl-aryl)benzenesulfonamides 1-6 were successfully synthesized by the reaction of 8-aminoquinoline and various benzenesulfonyl chlorides. Then, half-sandwich ruthenium complexes 7-12 were prepared from the reactions of 1-6 with [RuCl2(p-cymene)]2. The synthesized compounds were characterized by NMR and FTIR spectroscopy and elemental analysis, and compounds 8 and 9 were further analyzed by X-ray diffraction. The complexes were screened for their efficiency as catalysts in the transfer hydrogenation of acetophenone derivatives to phenylethanols in the presence of KOH with 2-propanol (as hydrogen source) at 82 °C, and they all showed good activity. Complexes 10 and 12 were the most active (turnover frequency values: 703 and 734 h-1, respectively)