Peroxido complexes of vanadium

Abstract

Peroxido complexes represent an important group of vanadium compounds having practical applications in distinct areas of chemistry. They possess insulin mimetic properties, antitumor activity and stimulate or inhibit certain enzymes. The bioinorganic chemistry of peroxidovanadates studies also the role of vanadium in the active centers of vanadium dependent enzymes (haloperoxidases and nitrogenases). Peroxidovanadium compounds are intensively studied for their oxidative properties. They can act as catalysts or stoichiometric oxidants in oxidation reactions of organic compounds, e.g. in epoxidation, sulfoxidation, hydroxylation or bromination. This versatility of vanadium peroxido complexes necessitates a critical review of their molecular structure and properties both in solution and in solid state. In this inclusive review we present the complete set of peroxido complexes of vanadium heretofore characterized by X-ray diffraction analysis. Along with the molecular structures we present and discuss the solid state vibrational spectra and thermal decomposition data. Vibrational, UV–vis and 51V NMR spectraof complexes dissolved in various solvents are also discussed. We have extracted the data from several speciation studies in order to clarify the formation conditions for different types of peroxidovanadates and summarize their 51V NMR chemical shifts. We also refer to certain applications of peroxido complexes of vanadium and we place the emphasis on potential applications which have not yet been thoroughly examined but deserve more attention.