Trinuclear ruthenium carbonyl complexes with salicylaldimine ligands as efficient catalysts for the oxidation of secondary alcohols

摘要

A series of novel trinuclear ruthenium carbonyl complexes [mu-eta(2)-2-OC6H4-CH=N Ar)](2)Ru-3(CO)(8)[Ar = Ph (8), C6H4-4-Me (9), C6H4-4-CF3 (10), C6H4-4-Cl (11), C6H3-2,6-Me-2 (12), C6H3-2,6-Et-2 (13)] and [mu-eta(2)-2-OC6H4-CH=N-C6H3-2,6(i)Pr(2)]Ru-3(CO)(9) (14) were designed and synthesized. All the seven novel complexes were fully characterized by elemental analysis, IR and NMR spectroscopy. Molecular structures of 8, 11, 13 and 14 were further confirmed by single-crystal X-ray diffraction. The catalytic performance of these complexes in the oxidation of secondary alcohols was explored and it was found the combination of such complexes and N-methylmorpholine-N-oxide (NMO) exhibits high catalytic activities for the oxidation of secondary alcohols, giving the corresponding carbonyl compounds in excellent yields. (C) 2020 Elsevier B.V. All rights reserved.