Direct Evidence for Oxygen‐Atom Exchange between Nonheme Oxoiron(IV) Complexes and Isotopically Labeled Water

Rates of exchange: Evidence that nonheme oxoiron(IV) complexes exchange their oxygen atoms with H218O was obtained for the first time, by monitoring electrospray ionization mass spectral changes of the oxoiron(IV) species. The oxygen-atom exchange depended markedly on the amounts of H218O present and reaction temperatures but not on the presence of trans axial ligand (see scheme).