Novel Tungsten, Molybdenum, and Vanadium Oxides Containing Surfactant Ions

Abstract

Hydrothermal reaction of tungstic acid, molybdic acid, and vanadium pentoxide with the surfactant template dodecyltrimethylammonium bromide (DTABr) yielded one compound with a Keggin type structure, [C12H25N(CH3)3]6(H2W12O40)·xH2O, and two new layered compounds, [C12H25N(CH3)3]0.5(MoO3.25) and [C12H25N(CH3)3]2/3V2O5.33·H2O. The tungsten salt produced needlelike crystals of a hexagonal shape while the molybdenum and vanadium salts formed layered structures. FTIR analysis of the tungsten salt was consistent with materials containing Keggin anions. The X-ray powder diffraction data of this material were indexed to a monoclinic cell with a = 50.56(4) Å, b = 54.41(4) Å, c = 13.12(1) Å, and β = 99.21°. The observed reflections are consistent with space group C2/m. Diffraction data obtained from the molybdenum salt showed a between layer d spacing of ca. 22 Å. The vanadium salt was indexed to a triclinic cell with a = 9.813(3) Å, b = 11.512(3) Å, c = 21.725(5) Å, α = 95.30(1)°, β = 93.82(6)°, and γ = 101.12(8)°, with a layer spacing of 21.6 Å.