Synthesis and spectroscopic characterization of organophosphono derivatives of lindqvist niobotungstates -: X-ray crystal structures of (nBu4N)3[NbW10O38(RP)2] (R = nBu, Hep and Ph)

A series of organophosphonopolyoxoniobotungstates [NbW10O38(RP)(2)](3-) {R = Me (1), Et (2), Pr (3), nBu (4), Hex (5), Hep (6), Cy (7), Ph (8), All (9)} has been prepared by the reaction of (nBu(4)N)(3)[NbW5O19] with the appropriate organophosphono dichloride, RP(O)Cl-2. All of the products were characterized by infrared and multinuclear ( P-31 and W-183) NMR spectroscopy. Compounds 4, 6 and 8 were characterized by single-crystal X-ray diffraction. The hybrid anions [NbW10O38(RP)(2)](3-) are made up of two W5O18 subunits, which can be viewed as monovacant derivatives of the mobotungstate precursor linked by a {Nb(OPR)(2)} group. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008).