How do corroles stabilize high valent metals?

Trianionic corroles are readily oxidized, yet they are able to stabilize metals in high oxidation states. In an attempt to solve this apparent puzzle, we have estimated both metal d and corrole pi orbital energies by analysis of well established experimental data. Although the corrole pi orbitals are at higher energies than those of closely related porphy-rins, the d orbital energies are even higher, owing to greatly enhanced a bonding dictated by the relatively rigid macrocyclic trianionic-ligand framework. Understanding the relative importance of corrole pi and a effects sheds new light on metallocorrole stability and reactivity that in turn will further advance this hot area of chemistry.