(727d) Existence of Vanadium Umbrella Structure in Biocatalyst Systems Only

Recent debates over the active site structure of vanadia/silica catalysts have suggested the existence of a vanadia peroxo-oxo ?umbrella? structure. This study shows the existence of an umbrella-like structure in biocatalyst systems only, and not on supported oxide catalysts such as vanadia on silica. Spectroscopic evidence shows that vanadia supported on silica is present as a pyramidal structure and maintains this arrangement under methanol oxidation conditions. However, the active site of vanadium haloperoxidase (VHPO) enzymes, and the active site of metal-organic mimic compounds designed to mimic VHPOs, exist as a vanadium peroxo-oxo umbrella structure.