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

Syntheses and Characterization of W(NC6F5)F5- and W2(NC6F5)2F9- Salts and Computational Studies of the W(NR)F5- (R = H, F, CH3, CF3, C6H5, C6F5) and W2(NC6F5)2F9- Anions

Convenient preparative routes to fluorido[(pentafluorophenyl)imido]tungstate(VI) salts have been developed. The reaction of WF₆·NC₅H₅ or [N(CH₃)₄][WF₇] with C₆F₅NH₂ results in quantitative formation of the C₅H₅NH⁺ or N(CH₃)₄⁺ salt of the W(NC₆F₅)F₅^- anion, respectively. The dissolution of [C₅H₅NH][W(NC₆F₅)F₅] in anhydrous HF results in the formation of [C₅H₅NH][W₂(NC₆F₅)₂F₉]. These salts have been comprehensively characterized in the solid state by X-ray crystallography and Raman spectroscopy and in solution by ¹⁹F and ¹H NMR spectroscopy. The crystal structures of the W(NC₆F₅)F₅^- salts reveal conformational differences in the anions, and the ¹⁹F NMR spectra of these salts in CH₃CN reveal coupling of the axial fluorido ligand to the ¹⁴N nucleus of the imido ligand. In addition, density functional theory (DFT-B3LYP) calculations have been performed on a series of W(NR)F₅^- anions (R = H, F, CH₃, CF₃, C₆H₅, C₆F₅) and the W₂(NC₆F₅)₂F₉^- anion, including gas-phase geometry optimizations, vibrational frequencies, molecular orbitals, and natural bond orbital (NBO) analyses.

A highly selective and sensitive fluorescence “turn-on” fluoride ion sensor

A highly selective and sensitive fluorescence “turn-on” and colorimetric dual-channel fluoride ion sensor.