Solvent effects on the catalytic activity of manganese(III) corroles

Four Mn(III) corroles that differ in their electronic environments based on mesosubstitution by pentafluorophenyl and phenyl groups were synthesized and characterized by spectroscopic techniques. Utilization of these Mn(III) corroles for styrene oxidation using iodosylbenzene (PhIO) as oxygen source in toluene, dichloromethane (DCM), DMF, DMAc, THF and DMSO revealed a remarkable effect of solvent on the catalytic activity. Furthermore, the transformation of Mn(III) corroles into their corresponding Mn(V)-oxo corroles, and subsequent treatment with styrene also indicated that more electron-deficient Mn(V)-oxo corroles exhibit higher reactivity in toluene and DCM, while less electron-deficient Mn(V)-oxo corroles exhibit higher reactivity in DMF and DMAc. A significant difference in the observed rates of reaction suggest that the catalytic oxidation of styrene by manganese corroles may proceed through different pathways, and is strongly solvent-dependent.