Synthesis of [F3SNXeF][AsF6] and Structural Study by Multi-NMR and Raman Spectroscopy, Electronic Structure Cal
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- 作者：Gregory L. Smith ; Hé ; lè ; ne P.A. Mercier ; Gary J. Schrobilgen
- 刊名：Inorganic Chemistry
- 出版年：2007
- 出版时间：February 19, 2007
- 年：2007
- 卷：46
- 期：4
- 页码：1369 - 1378
- 全文大小：166K
- 年卷期：v.46,no.4(February 19, 2007)
- ISSN：1520-510X
文摘
The salt, [F3S
ntities/tbd1.gif">NXeF][AsF6], has been synthesized by the reaction of [XeF][AsF6] with liquid Nntities/tbd1.gif">SF3 at -20 ntities/deg.gif">C.The Xe-N bonded cation provides a rare example of xenon bound to an inorganic nitrogen base in which nitrogenis formally sp-hybridized. The F3Sntities/tbd1.gif">NXeF+ cation was characterized by Raman spectroscopy at -150 ntities/deg.gif">C and by129Xe, 19F, and 14N NMR spectroscopy in HF solution at -20 ntities/deg.gif">C and in BrF5 solution at -60 ntities/deg.gif">C. Colorless[F3Sntities/tbd1.gif">NXeF][AsF6] was crystallized from HF solvent at -45 ntities/deg.gif">C, and its low-temperature X-ray crystal structure wasdetermined. The Xe-N bond is among the longest Xe-N bonds known (2.236(4) Å), whereas the Xe-F bondlength (1.938(3) Å) is significantly shorter than that of XeF2 but longer than in XeF+ salts. The Xe-F and Xe-Nbond lengths are similar to those of HCntities/tbd1.gif">NXeF+, placing it among the most ionic Xe-N bonds known. The nonlinearXe-N-S angle (142.6(3)o) contrasts with the linear angle predicted by electronic structure calculations and isattributed to close N···F contacts within the crystallographic unit cell. Electronic structure calculations at the MP2and DFT levels of theory were used to calculate the gas-phase geometries, charges, bond orders, and valenciesof F3Sntities/tbd1.gif">NXeF+ and to assign vibrational frequencies. The calculated small energy difference (7.9 kJ mol-1) betweenbent and linear Xe-N-S angles also indicates that the bent geometry is likely the result of crystal packing. Thestructural studies, natural bond orbital analyses, and calculated gas-phase dissociation enthalpies reveal thatF3Sntities/tbd1.gif">NXeF+ is among the weakest donor-acceptor adducts of XeF+ with an Xe-N donor-acceptor interactionthat is very similar to that of HCntities/tbd1.gif">NXeF+, but considerably stronger than that of F3Sntities/tbd1.gif">NAsF5. Despite the lowdissociation enthalpy of the donor-acceptor bond in F3Sntities/tbd1.gif">NXeF+, 129Xe, 19F, and 14N NMR studies reveal that theF3Sntities/tbd1.gif">NXeF+ cation is nonlabile at low temperatures in HF and BrF5 solvents.
ntities/tbd1.gif">NXeF][AsF6], has been synthesized by the reaction of [XeF][AsF6] with liquid Nntities/tbd1.gif">SF3 at -20 ntities/deg.gif">C.The Xe-N bonded cation provides a rare example of xenon bound to an inorganic nitrogen base in which nitrogenis formally sp-hybridized. The F3Sntities/tbd1.gif">NXeF+ cation was characterized by Raman spectroscopy at -150 ntities/deg.gif">C and by129Xe, 19F, and 14N NMR spectroscopy in HF solution at -20 ntities/deg.gif">C and in BrF5 solution at -60 ntities/deg.gif">C. Colorless[F3Sntities/tbd1.gif">NXeF][AsF6] was crystallized from HF solvent at -45 ntities/deg.gif">C, and its low-temperature X-ray crystal structure wasdetermined. The Xe-N bond is among the longest Xe-N bonds known (2.236(4) Å), whereas the Xe-F bondlength (1.938(3) Å) is significantly shorter than that of XeF2 but longer than in XeF+ salts. The Xe-F and Xe-Nbond lengths are similar to those of HCntities/tbd1.gif">NXeF+, placing it among the most ionic Xe-N bonds known. The nonlinearXe-N-S angle (142.6(3)o) contrasts with the linear angle predicted by electronic structure calculations and isattributed to close N···F contacts within the crystallographic unit cell. Electronic structure calculations at the MP2and DFT levels of theory were used to calculate the gas-phase geometries, charges, bond orders, and valenciesof F3Sntities/tbd1.gif">NXeF+ and to assign vibrational frequencies. The calculated small energy difference (7.9 kJ mol-1) betweenbent and linear Xe-N-S angles also indicates that the bent geometry is likely the result of crystal packing. Thestructural studies, natural bond orbital analyses, and calculated gas-phase dissociation enthalpies reveal thatF3Sntities/tbd1.gif">NXeF+ is among the weakest donor-acceptor adducts of XeF+ with an Xe-N donor-acceptor interactionthat is very similar to that of HCntities/tbd1.gif">NXeF+, but considerably stronger than that of F3Sntities/tbd1.gif">NAsF5. Despite the lowdissociation enthalpy of the donor-acceptor bond in F3Sntities/tbd1.gif">NXeF+, 129Xe, 19F, and 14N NMR studies reveal that theF3Sntities/tbd1.gif">NXeF+ cation is nonlabile at low temperatures in HF and BrF5 solvents.