Yttrium containing head-on complexes of silico- and germanotungstate: Synthesis, structure and solution properties

Two dimeric head-on complexes of yttrium containing silico- and germanotungstate were isolated from the one-pot reaction of Y(NO3)3·6H2O with the lacunary Na10[MW9O34]·16H2O (M = Si and Ge) building blocks in an acetate buffer at pH 4.5. Both polyanions were structurally characterized using various solid-state analytics, such as single-crystal X-ray diffraction, single-crystal X-ray analysis shows that both polyanions crystallize in the monoclinic crystal system (S.G. P21/c). FT-IR spectroscopy, or thermogravimetric analysis. The stability of the polyanion in aqueous solution was studied by multinuclear NMR spectroscopy (183W, 89Y, 29Si, 13C, and 1H). As expected, the 183W NMR spectra display six peaks in the intensity ratio of 4:4:2:4:4:4 which indicates that both polyanions exist as dimeric entities in aqueous solution.