Epoxidations catalyzed by an ionic manganese(III) porphyrin and characterization of manganese(V, IV)-oxo porphyrin complexes by UV–vis spectrophotometer in ionic liquid solution

Abstract An ionic metalloporphyrin of manganese tetrakis-(4- N -trimethylaminophenyl)porphyrin hexafluorophosphate ([Mn III TTMAPP][PF 6 ] 5 , 1c ), resided in the mixed ionic liquids (ILs) of [BzMIM]BF 4 and [BMIM]BF 4 , proved to be an efficient and recyclable catalytic system for styrene (derivative) epoxidations without the involvement of the auxiliary axial ligands. The epoxidation rate in 1c –IL could be dramatically promoted by addition of water. In the built-up 1c –IL–H 2 O system, the active manganese(V)-oxo porphyrin intermediate ( 1d , 444 nm) was stabilized to facilitate its detection by a UV–vis spectrophotometer. And the formation of the μ-oxo Mn(IV) porphyrin dimer ( 1e , 416 nm) was completely suppressed due to the counteraction between 1c and the IL.