Metallocorroles with Formally Tetravalent Iron

The unusual oxidation state + IV for iron centers can be stabilized by porphyrin‐like corrole ligands in such a way that the compounds 1 (R  Cl, Ph, OFe‐corrole) can be isolated at room temperature. The oxygen‐bridged binuclear iron(IV) corrole, which can be readily converted into the mononuclear iron(IV) corrole, forms as the only defined product from the reaction of the ligand with [Fe₂(CO)₉] followed by workup in air. In contrast, only a few iron(IV) porphyrins are known so far, and these are too unstable to be isolated as solids. (Figure Presented.)