95Mo solid-state NMR spectra of molybdates

Abstract

95Mo solid-state NMR spectra of a variety of molybdates of alkali metals as well as molybdates of some divalent metals, MoO3, Mo(CO)6, polyoxo complexes H3PMo12O40·χH2O and [(C4H9)4N]4·[Mo8O26] are reported. Alkali-metal molybdates show mainly sharp single resonances. Signals from the molybdates of divalent metals show a splitting due to second-order quadrupole effects. For MoO3, signals from structurally inequivalent Mo sites seem to be resolved. The 95Mo spectrum of H3PMo12O40·χH2O exhibits a large chemical shift anisotropy, while for [(C4H9)4N]4·[Mo8O26] the superposition of a sharp peak from almost regular MoO4 tetrahedra and a broad line from Mo atoms in distorted octahedra is observed. For molybdates the resonances are shifted upfield with decreasing MoO bond length. The results can be used for studying molybdenum-based catalysts. © 1988.