Valence Tautomerization of High-Valent Manganese(V)-Oxo Corrole Induced by Protonation of the Oxo Ligand.

The addition of an organic acid to the manganese(V)-oxo corrole complex (tpfc)Mn(V)(O) (tpfc = 5,10,15-tris(pentafluorophenyl)corrole) induces valence tautomerization resulting in the formation of (tpfc(+•))Mn(IV)(OH) in acetonitrile at 298 K. The corrole radical cation manganese(IV) hydroxo complex has been fully characterized by EPR, (1)H NMR, and UV-vis spectroscopy. The reactivity of the valence tautomer (tpfc(+•))Mn(IV)(OH) is compared to that of (tpfc)Mn(V)(O) in three reaction types: hydrogen atom transfer (HAT), electron transfer (ET), and oxygen atom transfer (OAT). (tpfc(+•))Mn(IV)(OH) shows a dramatic 5 orders of magnitude enhancement in the rate of ET but surprisingly does not undergo OAT with PhSMe. The high-valent (tpfc)Mn(V)(O) complex is moderately more reactive toward HAT with substituted phenol and shows superior activity in OAT.