A highly efficient method of epoxidation of olefins with hydrogen peroxide catalyzed by changeable hexadentate 8-quinolinolato manganese(III) complexes

Novel hexadentate binding 8-quinolinolato manganese(III) complexes were proposed and conveniently synthesized for the epoxidation of olefins with aqueous hydrogen peroxide in water–acetone media with ammonium acetate and acetic acid as additives. The catalytic efficiencies of the suggested catalysts were found to be obviously superior to the traditional tetradentate salen–MnIIICl, due to their special hexadentate binding structures that could be easily converted to the corresponding pentadentate with pendant hydroxyl groups by opening an axial Mnsingle bondO bond in the reaction media, as supported by UV–vis spectra, in situ cyclic voltammetry, and quartz crystal microbalance characterizations.