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(+center dot))Mn-IV(OH) in acetonitrile at 298 K. The corrole radical cation manganese(IV) hydroxo complex has been fully characterized by EPR, H-1 NMR, and UVvis spectroscopy. The reactivity of the valence tautomer (tpfc(+center dot))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(+center dot))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.