Photolysis of CH3Re(O2)2O induced by ligand-to-metal charge transfer and by peroxide intraligand excitation

The electronic spectrum of the diperoxo complex MeReVII(O2)2O shows a peroxide IL (intraligand) absorption at λmax ∼ 260 nm in addition to the well known peroxide to Re(VII) LMCT band at λmax = 358 nm. Upon IL excitation, the diperoxo group undergoes a dismutation. Accordingly, MeRe(O2)2O photolyzes to MeReVIIO3 and O2. LMCT excitation at λirr = 405 nm is assumed to generate the radical pair MeReVI(O2)O+/O2- in the primary photochemical step. Back electron transfer and reaction with water leads finally to the monoperoxo complex MeReVII(O2)O2 and H2O2.