Direct evidence for oxygen-atom exchange between nonheme oxoiron(IV) complexes and isotopically labeled water.

The establishment of the involvement of high-valent iron-oxo intermediates in the catalytic cycles of heme and nonheme iron monooxygenases and their model compounds has been an important goal in mechanistic enzymology and bioinorganic chemistry. 2] These highly reactive and unstable intermediates are often difficult to characterize directly; therefore, O-labeled water experiments have frequently been carried out to obtain indirect insight into the nature of the reactive intermediates involved in the catalytic oxygenation reactions. Since metal-oxo species can in principle exchange their oxygen with labeled water prior to oxo transfer to organic substrates (Scheme 1), the incorporation of labeled O from H2 O into oxidation products has been