Oxidative transformations in the VV/H2O2/RCOOH system

In order to reveal the nature of intermediates of peroxide oxidation catalysed by vanadium compounds, the inner-sphere transformations of vanadium(V) peroxo complexes with the general formula [VO₆]^– has been studied in approximations of the density functional theory (B3LYP/6-31G**) and Møller–Plesset perturbation theory (MP2/6-31G**). It has been found that the triperoxo complex [V(η–O₂)₃]^– undergoes isomerization to a complex that is unexpectedly more stable, [V(=O)(η–O₂)(O₃)]^–, which incorporates an O₃ group as a bidentate ligand. This reaction was found to occur via two intermediate complexes that can transfer both singlet dioxygen and an oxygen atom to a substrate molecule. The reaction scheme proposed on the basis of calculations is in qualitative agreement with the previously obtained kinetic regularities of ozone formation and oxidation of alkanes, alkenes, arenes and singlet dioxygen acceptors in the V^V/H₂O₂/RCOOH catalytic system.