Organic−Inorganic Hybrids Based on Polyoxometalates. 5.¹Synthesis and Structural Characterization of Bis(organophosphoryl)decatungstosilicates [γ-SiW₁₀O₃₆((RPO)₂]⁴^-

Abstract

Organophosphoryl polyoxotungstate derivatives [gamma-SiW(10)O(36)(RPO)(2)](4)(-) (R = H (1), Et (2), n-Bu (3), t-Bu (4), C(2)H(4)COOH (5), Ph (6)) have been obtained by reaction of the divacant [gamma-SiW(10)O(36)](8)(-) anion with organophosphonic acids RPO(OH)(2) in acetonitrile. These new heteropolyanions have been characterized by elemental analysis, infrared spectroscopy, multinuclear ((1)H, (29)Si, (31)P, and (183)W) NMR, and X-ray crystallography. Crystals of (NBu(4))(2)(NEt(4))H[gamma-SiW(10)O(36)(C(6)H(5)PO)(2)] (anion 6) are monoclinic, space group P2(1), with lattice constants a = 16.489(4) Å, b = 14.016(3) Å, c = 18.542(8) Å, beta = 91.30(3) degrees, and Z = 2. The hybrid anion has a structure of virtual C(2v)() symmetry with two phenylphosphonate groups grafted to the surface of the divacant tungstosilicate. (183)W and (31)P NMR spectra of NBu(4) salts in DMF solution agree with the solid-state structure and the virtual C(2)(v)() symmetry.