Biomimetic Alkane Hydroxylations by an Iron(III) Porphyrin Complex with H2O2 and by a High-Valent Iron(IV) Oxo Porphyrin Cation Radical Complex

Abstract

An iron(III) porphyrin complex with highly electron-withdrawing substituents on the porphyrin ligand efficiently catalyzes the hydroxylation of alkanes by H2O2 via enzyme mimetic oxidation reactions in aprotic solvent. An “isolated” high-valent iron(IV) oxo porphyrin cation radical intermediate, prepared in situ by reaction of the iron porphyrin complex with m-CPBA at −40 °C, is capable of activating C−H bonds of alkanes to give oxygenated products efficiently. The hydroxylating intermediate generated in the catalytic H2O2 reaction is evidenced to be the high-valent iron(IV) oxo porphyrin cation radical species.