Accession Number : ADA290761

Title :   The Redox Chemistry of Some Peroxo and Superoxo Metal Ion Complexes.

Descriptive Note : Final rept. 15 Apr 91-14 Oct 94,

Corporate Author : MISSOURI UNIV-COLUMBIA DEPT OF CHEMISTRY

Personal Author(s) : Thompson, Richard C.

PDF Url : ADA290761

Report Date : 18 NOV 1994

Pagination or Media Count : 5

Abstract : All mononuclear peroxomolybdales and peroxovanadates, which form rapidly over virtually the entire pH range in aqueous solution, have been fully characterized and their formation constants determined. The reactivities of the mono- and diperoxo complexes have been examined; the peroxo ligands are strongly activated by Mo(VI) and mildly so by V(V). Mo(VI) and W(VI) are highly effective and robust catalysts for oxidations by hydrogen peroxide, and should find a number of practical uses in the near future. The system Mo(VI), H2O2, and base is probably the most promising chemical means of producing singlet oxygen known. Substantial progress has been made in elucidating the mechanistic aspects of these systems. Incorporation of heteroligands in peroxometallates does not appear to significantly the redox reactivity of the peroxo ligand(s), but can profoundly affect the lability of the peroxo ligand and also render the peroxo complex soluble in nonaqueous media. Preliminary experiments have revealed that calorimetry is the method of choice to determine formation constants for polynuclear peroxometallates. These species are of importance when relatively high concentrations of catalyst are employed, as will probably be the case in some practical applications. The formation constants are prerequisite to meaningful reactivity studies of these polynuclear complexes. (jg)

Descriptors :   *IONS, *OXIDATION REDUCTION REACTIONS, *METAL COMPLEXES, *HYDROGEN PEROXIDE, HIGH RATE, SOLUTIONS(MIXTURES), WATER, REACTIVITIES, OXYGEN, CHEMISTRY, LIGANDS, CATALYSTS, KINETICS, TUNGSTEN, PH FACTOR, CONCENTRATION(CHEMISTRY), VANADIUM, CALORIMETRY, COMPLEX IONS.

Subject Categories : Inorganic Chemistry
      Physical Chemistry

Distribution Statement : APPROVED FOR PUBLIC RELEASE