Rates of oxygen exchange between phosphomolybdovanadium heteropolyanions and water according to 17O NMR

The method of 17O NMR has been used for studying the kinetics of isotopic exchange 16O-17O between the oxygen atoms of heteropolyanion (HPA), and oxygen atoms of water molecules used as a solvent. The NMR spectra and the rates of enrichment with oxygen-17 of HPA of the composition of PMosub(12-n)Vsub(n)Osub(40)sup(n+3) (n=0.12) and V10O286- (HPA-0, HPA-1, HPA-2, and decavanadate, respectively) have been measured. On the basis of the data obtained the corresponding rate constants were found, and conclusions were made about the state and structure of HPA under conditions close to those observed in catalytic processes