Enhanced photoreactivity of zirconium(IV) and hafnium(IV) porphyrin complexes promoted by water molecules

The visible-light-induced photoreduction of zirconium and hafnium tetraphenylporphyrin derivatives carrying axial benzoato ligands yields the corresponding two-electron-reduced porphodimethene metal complexes and requires the assistance of water as an essential cofactor for substrate conversion in degassed solution.