Solid-State and Solution Rearrangements of F₃S≡NXeF⁺Leading to the F₄S═NXe⁺Cation; Syntheses, HF Solvolyses, and Structural Characterizations of [F₄S═NXe][AsF₆] and [F₄S═NH₂][AsF₆]

Abstract

The salt, [F(4)S=NXe][AsF(6)], has been synthesized by the solid-state rearrangement of [F(3)S[triple bond]NXeF][AsF(6)] and by HF-catalyzed rearrangement of [F(3)S[triple bond]NXeF][AsF(6)] in anhydrous HF (aHF) and HF/BrF(5) solvents. The F(4)S=NXe(+) cation undergoes HF solvolysis to form F(4)S=NH(2)(+), XeF(2), and the recently reported F(5)SN(H)Xe(+) cation. Both [F(4)S=NXe][AsF(6)] and [F(4)S=NH(2)][AsF(6)] have been characterized by (129)Xe and (19)F NMR spectroscopy in aHF and HF/BrF(5) solvents and by single-crystal X-ray diffraction. The [F(4)S=NXe][AsF(6)] salt was also characterized by Raman spectroscopy. The Xe-N bond of F(4)S=NXe(+) is among the shortest Xe-N bonds presently known (2.084(3) A), and the cation interacts with the AsF(6)(-) anion by means of a Xe---F-As bridge in which the Xe---F distance (2.618(2) A) is significantly less than the sum of the Xe and F van der Waals radii. Both F(4)S=NXe(+) and F(4)S=NH(2)(+) exhibit trigonal bipyramidal geometries about sulfur, with nitrogen in the equatorial plane and the nitrogen substituents coplanar with the axial fluorine ligands of sulfur. The F(4)S=NH(2)(+) cation is isoelectronic with F(4)S=CH(2) and, like F(4)S=CH(2), has a high barrier to rotation about the S=N double bond and to pseudorotation of the trigonal bipyramidal F(4)S=N- moiety. The solution and solid-state rearrangements of F(3)S[triple bond]NXeF(+) to F(4)S=NXe(+) are proposed to result from attack at sulfur by fluoride ion arising from HF in solution and from the AsF(6)(-) anion in the solid state. Quantum-chemical calculations were employed to calculate the gas-phase geometries, charges, bond orders, valencies, and vibrational frequencies of F(4)S=NXe(+) and F(4)S=NH(2)(+). The F(4)S=NXe(+) cation provides the first example of xenon bonded to an imido-nitrogen, and together with the F(4)S=NH(2)(+) cation are presently the only cations known to contain the F(4)S=N-group. Both cations are intermediates in the HF solvolysis pathways of F(3)S[triple bond]NXeF(+) which lead to F(5)SN(H)Xe(+) and F(5)SNH(3)(+), and significantly extend the chemistry of the F(4)S=N-group.

Nature of the XeVI−N Bonds in F6XeNCCH3and F6Xe(NCCH3)2and the Stereochemical Activity of Their Xenon Valence Electron Lone Pairs

“…ÀNb onds occur for trigonal planar (sp 2 -hybridized) inorganic nitrogen ligandsd erived from the (FO 2 S) 2 N( imidobis(sulfurylfluoride)) group, that include FXeN(SO 2 F) 2 , [15][16][17] + , [19] the related (CF 3 O 2 S) 2 N( imidobis(sulfuryltrifluoromethyl)) group, which is solely represented by (Xe[N-(SO 2 CF 3 ) 2 ] 2 ), [20] and the sulfur-nitrogen-fluorine cations derived from NSF 3 ,n amely, [ F 4 S=NXe] + [21] and [F 4 S=NXe···NSF 3 ] + . [22] The only examples in which xenon is bonded to sp 3 -hybridized nitrogen are [F 5 Te N(H)Xe]…”

Gas-Phase Ion Chemistry of the Noble Gases: Recent Advances and Future Perspectives

“…A second group of condensed-phase Xe-N cations includes (FO 2 S) 2 NXe + , 258,259 F 5 SN(H)Xe + , 257,260 F 5 TeN(H)Xe + , 261 and F 4 S=NXe + . 257,262,263 These species can be regarded as a Xe atom that interacts with the nitrenium ions (FO 2 S) 2 N + , F 5 SN(H) + , F 5 TeN(H) + and F 4 S=N + and are invariably characterized by covalent Xe-N bonds, with short distances of nearly 2.0-2.1 Å. Very recently, 231 the xenon-difluoronitrenium cation F 2 N-Xe + was obtained in the gas phase from Reaction (2) F 2 N-FH + + Xe ® F 2 N-Xe + + HF (2) observed by IT-MS. Based on theoretical results, the ionic product was unambiguously assigned as F 2 N-Xe + .…”

Xenon–Nitrogen Chemistry: Gas‐Phase Generation and Theoretical Investigation of the Xenon–Difluoronitrenium Ion F2NXe+

“…[22,23] In subsequent years, xenonnitrogen chemistry was considerably expanded, noticeably by Schrobilgen and co-workers, [24][25][26][27][28][29][30][31][32][33] and evidence for novel compounds is still emerging. [34,35] In general, apart from the molecular species FXeNA C H T U N G T R E N N U N G (SO 2 F) 2 , [18,20,22,23] Xe[N-A C H T U N G T R E N N U N G (SO 2 F) 2 ] 2 , [20,24] and Xe[NA C H T U N G T R E N N U N G (SO 2 CF 3 ) 2 ] 2 , [21] the xenon-nitrogen compounds observed in the condensed phase are salts of Xe À N cations and counteranions such as AsF 6 À , Sb 3 F 16 À , and BY 4 À (Y=CF 3 , C 6 F 5 ). The Xe À N cations can be in turn divided into two groups.…”

“…À ] salt [34,35] can be also included in this series. Whereas (FO 2 S) 2 NXe + presents a planar arrangement around the N atom and involves, like F 4 S=NXe + , an sp 2 -hybridized nitrogen, the group 16 homologues F 5 SN(H)Xe + and F 5 TeN(H)Xe + present nonplanar N atoms, and are indeed rare examples of xenon bonded to sp 3 -hybridized nitrogen.…”

“…The Lewis acidity of C 6 F 5 Xe + is considerably lower than that of XeF + , and the Xe À N bond lengths of the C 6 F 5 Xe À N CCH 3 + cation observed in the corresponding salts with BY 4 À (Y=CF 3 , C 6 F 5 ) [30] and (C 6 F 5 ) 2 BF 2 À [36] are consistently as long as 2.6-2.7 . A second group of XeÀN cations includes (FO 2 S) 2 NXe + , [19,25] F 5 SN(H)Xe + , [33] and F 5 TeN(H)Xe + [30] (observed as salts of AsF 6 À or Sb 3 F 16 À ), and can be regarded as an Xe atom that interacts with the homo-or heterosubstituted nitrenium ions (FO 2 S) 2 [34,35] can be also included in this series. Whereas (FO 2 S) 2 hybridization, these cations are invariably characterized by covalent Xe À N bonds, with observed short distances of nearly 2.0-2.1 .…”