On the Reactivity of F3S≡NXeF+: Syntheses and Structural Characterizations of [F4S═N−Xe---N≡SF3][AsF6], a Rare Example of

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• 作者：Gregory L. Smith ; Gary J. Schrobilgen
• 刊名：Inorganic Chemistry
• 出版年：2009
• 出版时间：August 17, 2009
• 年：2009
• 卷：48
• 期：16
• 页码：7714-7728
• 全文大小：1092K
• 年卷期：v.48,no.16(August 17, 2009)
• ISSN：1520-510X

文摘

The F₄S═N−Xe---N≡SF₃⁺ cation has been synthesized as the AsF₆⁻ salt by rearrangement of [F₃S≡NXeF][AsF₆] in N≡SF₃ solvent at 0 °C. Deep yellow [F₄S═N−Xe---N≡SF₃][AsF₆], which crystallized from a N≡SF₃ solution at −10 °C, was characterized by Raman spectroscopy (−160 °C) and by single-crystal X-ray diffraction (−173 °C). The Xe−N bond length (2.079(3) Å) of the F₄S═N−Xe---N≡SF₃⁺ cation is among the shortest Xe−N bonds presently known. The F₄S═NXe⁺ cation interacts with N≡SF₃ by means of a Xe---N donor-acceptor bond (2.583(3) Å) that is significantly longer than the primary Xe−N bond (2.079(3)Å) but significantly shorter than the sum of the Xe and N van der Waals radii (3.71 Å). The F₄S═N−Xe---N≡SF₃⁺ cation undergoes a redox decomposition in N≡SF₃ at 0 °C, forming [F₃S(N≡SF₃)₂][AsF₆], cis-N₂F₂, and Xe, which were characterized by low-temperature Raman spectroscopy in the solid state and by ¹⁹F NMR spectroscopy in N≡SF₃ solvent (0 °C). Colorless [F₃S(N≡SF₃)₂][AsF₆] crystallized from N≡SF₃ at −10 °C and was characterized by low-temperature, single-crystal X-ray diffraction. The S(IV) atom of F₃S(N≡SF₃)₂⁺ has long contacts with the N atoms of two N≡SF₃ molecules and a F ligand of a neighboring AsF₆⁻ anion. The arrangement of long contacts avoids, to the maximum extent, the F atoms of SF₃⁺ and the nonbonding electron pair situated on the pseudo-3-fold axis opposite the F ligands of SF₃⁺, providing distorted octahedral coordination about the S(IV) atom. Quantum-chemical calculations using MP2, B3LYP, and PBE1PBE methods were employed to arrive at the gas-phase geometries, charges, bond orders, valencies, and vibrational frequencies for F₄S═N−Xe---N≡SF₃⁺ and F₃S(N≡SF₃)₂⁺ to aid in the assignments of experimental vibrational frequencies. The F₄S═N−Xe---N≡SF₃⁺ cation expands the known chemistry of the F₄S═N− group and is the first example of a N−Xe−N linkage to be structurally characterized by single-crystal X-ray diffraction.