Trilacunary A-beta-Keggin tungstogermanates and -silicates functionalized with phenyltin(IV) electrophiles.

The first organic derivative of a beta-Keggin tungstogermanate, the monomeric Keggin anion {(C(6)H(5))Sn(OH)}(3)(A-beta-GeW(9)O(34)) (1), was the only species isolated from the reaction of (C(6)H(5))SnCl(3) with Na(10)[A-beta-GeW(9)O(34)] in water, whereas the Si-analogue {(C(6)H(5))Sn(OH)}(3)(A-beta-SiW(9)O(34)) (2) and two dimeric tungstosilicates, the unprecedented species {(C(6)H(5))Sn(A-beta-H(3)SiW(9)Sn(2)O(37))}(2)O(2) (3) and the known sandwich-type polyanion {(C(6)H(5))Sn(OH)}(3)(A-beta-H(3)SiW(9)O(34))(2) (4), were isolated starting from A-beta-SiW(9)O(34). The novel polyanion 3 can be described as the product of a double Sn-C hydrolysis followed by condensation of two subunits of 2 through double Sn-O-Sn bridge formation. Solid-state characterization has been carried out by infrared spectroscopy, thermogravimetry and single-crystal X-ray diffraction, representing the first structural analysis for 4. A full solution multinuclear NMR ((1)H, (13)C, (117)Sn, and (183)W) and solid-state (117)Sn CP-MAS NMR study enabled full characterization of 1. A weak 1-dimensional polyanion association through (Sn)O-HO(t) hydrogen contacts involving one of the protonated bridging O atoms of the (C(6)H(5))(3)Sn(3)O(12) corner-shared triad is observed for 1 by X-ray diffraction, resulting in a local C(s) pseudosymmetry for the Sn centers detected by solid-state (117)Sn NMR spectroscopy.