High‐field⁹⁵Mo and¹⁸³W static and MAS NMR study of polyoxometalates

Abstract

The potential of high-field NMR to measure solid-state Mo and W NMR in polyoxometalates (POMs) is explored using some archetypical structures like Lindqvist, Keggin and Dawson as model compounds that are well characterized in solution. NMR spectra in static and under magic angle spinning (MAS) were obtained, and their analysis allowed extraction of the NMR parameters, including chemical shift anisotropy and quadrupolar coupling parameters. Despite the inherent difficulties of measurement in solid state of these low-gamma NMR nuclei, due mainly to the low spectral resolution and poor signal-to-noise ratio, the observed global trends compare well with the solution-state NMR data. This would open an avenue for application of solid-state NMR to POMs, especially when liquid-state NMR is not possible, e.g., for poorly soluble or unstable compounds in solution, and for giant molecules with slow tumbling motion. This is the case of Keplerate where we provide here the first NMR characterization of this class of POMs in the solid state. Copyright © 2017 John Wiley & Sons, Ltd.

A Metal–Organic Framework with Tetrahedral Aluminate Sites as a Single‐Ion Li+ Solid Electrolyte

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Preparation of NHC Stabilized Al(III)fluorides: Fluorination of [(SIMes)AlMe3] with SF4 or Me3SnF

“…This resonance is consistent with data for four‐fold coordinated aluminium fluorides such as the complex [{HC(CMeNAr) 2 }Al(F) 2 ] (Ar = 2,6‐ i Pr 2 C 6 H 3 ) . A signal at δ = 49.8 ppm in the 27 Al NMR spectrum appears also in a typical range for fourfold coordinated aluminium halide species . The 19 F NMR spectrum shows two signals for CH 3 SF 3 at δ = –50.6 ppm and 60.9 ppm, which are in accordance to the literature …”

Alumina: discriminative analysis using 3D correlation of solid-state NMR parameters

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