Proton Sites in Keggin Heteropoly Acids from 17O NMR
, E-ISSN: 1572-879X
||17O MAS and solution NMR, determination of proton sites, tungsten heteropoly acids
van Bekkum H.
Boreskov Institute of Catalysis, 630090 Novosibirsk, Russia
Laboratory of Organic Chemistry and Catalysis, Delft University of Technology, Julianalaan 136, 2628 BL Delft, The Netherlands
The structure of the bulk proton sites in dehydrated solid Keggin-type heteropoly acids (HPA) H3PW12O40 and H4SiW12O40 was determined by 17O NMR. The terminal W=O oxygen atoms in Keggin heteropolyanions were found to be the predominant protonation sites. The protonation of HP As in solution is also discussed on the basis of 17O NMR data.