SYNTHESIS AND V-51 AND W-183 NMR-STUDY OF ALPHA-K6H[GEW9V3O40].XH2O AND BETA-K6H[GEW9V3O40].XH2O

The trivanadium-substituted polyoxoanions A-alpha and A-beta-K6H[GeW9V 3O40] . xH2O have been synthesized from their lacunary precursors alph a- and beta-GeW9O3410-, and characterized by elemental analysis, IR, c yclic voltammogram and V-51 and W-183 NMR. W-183 NMR spectra of the ti tle anions consist of two lines (intensity ratio 2:1) as expected for the C3v structures of the trisubstituted Aalpha- and Abeta-Keggin anio ns. The 2J(W-O-W) couplings of title anions exhibits sharper lines (19 .35 and 16.73 Hz respectively), confirming the A-type [GeW9V3O40]7- st ructure, that is the new complexes contain the substituted vanadium in adjacent corner-shared octahedra of alpha- and beta-Keggin structures respectively.