A series of hexadentate 8-quinolinolato manganese(III) complexes were synthesized and proven to own a distorted octahedral geometry via elemental analysis, solid UV-vis spectroscopy and Hartree-Fock/3-21G+ calculation. These Mn(III) complexes were found to be more efficient than their corresponding tetradentate 8-quiriolinolato manganese(II) and salen-(MnOAc)-O-III for the oxidation of alcohols in acetone medium, being due to their special hexadentate binding structures that could open an axial Mn-O bond to form the more active pentadentate Structures in the presence of aqueous hydrogen peroxide, as supported by UV-vis spectra. The halogen substituents in ligand's aryl ring could significantly enhance the catalytic activities and 5-chloro-7-iodo-8-quinolinolato manganese(III) gave the highest turnover number (TON). A reasonable mechanism for the present catalytic system was proposed. (C) 2008 Elsevier Inc. All rights reserved.