5-chloro-7-iodo-8-quinolinolatomanganese(III) with the feature of pH-regulated molecular switches as a highly efficient catalyst for epoxidation of olefins with hydrogen peroxide

A simple 5-chloro-7-iodo-8-quinolinolato-manganese(III) complex with the feature of pH-regulated molecular switches was conveniently synthesized and found to be a novel and highly efficient catalyst for the epoxidation of olefins with aqueous hydrogen peroxide in water-acetone media containing ammonium acetate and acetic acid as additives. This should be due to its special hexadentate binding structure that could be easily converted to the corresponding pentadentate form with a pendant hydroxy group via the opening of an axial Mn-O bond in the reaction media, as supported by in situ cyclic voltammetry and UV-vis spectra characterization.