Fluoride-Ion Acceptor Properties of WSF4: Synthesis, Characterization, and Computational Study of the WSF5– and W2S2F9– Anions and 19F NMR Spectroscopic Characterization of the W2OSF9– Anion

The new [N(CH3)4][WSF5] salt was synthesized by two preparative methods: (a) by reaction of WSF4 with [N(CH3)4][F] in CH3CN and (b) directly from WF6 using the new sulfide-transfer reagent [N(CH3)4][SSi(CH3)3]. The [N(CH3)4][WSF5] salt was characterized by Raman, IR, and 19F NMR spectroscopy and [N(CH3)4][WSF5]·CH3CN by X-ray crystallography. The reaction of WSF4 with half an aliquot of [N(CH3)4][F] yielded [N(CH3)4][W2S2F9], which was characterized by Raman and 19F NMR spectroscopy and by X-ray crystallography. The WSF5– and W2S2F9– anions were studied by density functional theory calculations. The novel [W2OSF9]− anion was observed by 19F NMR spectroscopy in a CH3CN solution of WOF4 and WSF5–, as well as CH3CN solutions of WSF4 and WOF5–.