VANADIUM BROMOPEROXIDASES MIMICKING SYSTEMS - BROMOHYDRINS FORMATION AS EVIDENCE OF THE OCCURRENCE OF A HYPOBROMITE-LIKE VANADIUM COMPLEX

In the aqueous phase of a two-phase (H2O-CH2Cl2) system mimicking the hydrophilic and the hydrophobic portions of vanadium dependent bromoperoxidases, (V-BrPO), a mono peroxovanadium complex, formed in situ by addition of H2O2 to NH4VO3, oxidizes Br- to a species whose nature is still largely unknown. Such species displays a bromine-like reactivity toward organic substrates dissolved in CH2Cl2. The observation that styrene, 1-methyl- and 2-methyl styrenes afford, together with dibromo-compounds, appreciable amounts of bromohydrins, suggests that a hypobromite-like species is also formed. Evidence is presented that such a species is a vanadium complex.