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

Wachs, I. E., Lehigh University
Molinari, J. E., Lehigh University
Podkolzin, S. G., Stevens Institute of Technology

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.