6F₅)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]]>

摘要

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.]]>