Efficient acceptorless dehydrogenative oxidation of alcohols catalyzed by ruthenium(II) complexes containing schiff base ligands

The catalytic performance of ruthenium carbonyl complexes containing Schiff base ligands [RN--CH (C10H6O)]2Ru(CO)2 [R = C6H5 (1); 4-CH3C6H4 (2); 4-OCH3C6H4 (3); R = 2,6-(CH3)2C6H3 (4); 4-ClC6H4 (5); 4BrC6H4 (6); 4-CF3C6H4 (7)] were explored in acceptorless dehydrogenative oxidation of alcohols with the releasing of hydrogen as the only by-product. All the Ru complexes 1-7 demonstrated good catalytic activities in oxidation of secondary alcohols to furnish the corresponding ketone products in excellent yields. Moreover, these Ru complexes displayed good selectivity in oxidation of primary alcohols to affording the aldehydes as the final products in 37-96 % yields. Among the complexes, the complex 7, which having an electron-withdrawing group (-CF3) showed the best catalytic activity.