Page 347 - Academic Press Encyclopedia of Physical Science and Technology 3rd InOrganic Chemistry

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Encyclopedia of Physical Science and Technology EN010K-480 July 16, 2001 17:22

Noble-Gas Chemistry 457

16.5 C] and Xe(OClO 3 ) 2 [yellow solid, mp (dec), 0 C] are structure shows that the compound contains XeN(SO 2 F) +
◦
◦
2
violent detonators. The compounds Xe(OC(O)CF 3 ) 2 and cations fluorine bridged to the Sb 3 F − anion through the
16
˚
FXeOC(O)CF 3 are pale yellow solids which decompose xenon atom [Xe--F bridge bond distance = 2.457(8) A].
˚
within a few hours at room temperature, but can deto- The Xe N bond length is 2.02(1) A. The disubstituted
nate above −20 C if thermally or mechanically shocked. compound Xe[N(SO 2 F) 2 ] 2 is a white solid and is pre-
◦
The nitrates FXeONO 2 and Xe(ONO 2 ) 2 have not been pared by the reaction of XeF 2 and HN(SO 2 F) 2 in a 1:2
isolated, but have been inferred from analysis of the de- molar ratio or by the reaction of FXeN(SO 2 F) 2 with
composition products of the reaction of XeF 2 with pure HN(SO 2 F) 2 in a 1:1 molar ratio. Quantitative decomposi-
◦
HNO 3 . tion to xenon and [N(SO 2 F) 2 ] 2 occurs rapidly at 22 C. The
The formation of xenon–oxygen bonded species in the compound Xe[N(SO 2 CF 3 ) 2 ] 2 is a white solid prepared by
reaction of XeF 2 with excess WOF 4 at low tempera- reaction of (CH 3 ) 3 SiN(SO 2 CF 3 ) 2 with XeF 2 in CF 2 Cl 2 at
ture (−121 C) in SO 2 ClF has been observed by NMR −22 to 10 C and is stable indefinitely at room tempera-
◦
◦
spectroscopy and is formulated as FXe OWF 5 (WOF 4 ) ture. Rapid decomposition at 72 C produces xenon, C 2 F 6 ,
◦
and FXe OWF 5 (WOF 4 ) 2 . The fluorine bridged adducts (CF 3 SO 2 ) 2 NCF 3 , and CF 3 SO 2 NSO 2 .
FXeFMOF 4 (M = W, Mo) undergo solvolysis in HSO 3 F Fluorine bridge formation between the cation and
solvent (−80 C) to give the fluorosulfate bridged species fluoroanion in complex XeF + salts (see Section III.E)
◦
FXe O(F)S( O)O MOF 4 (M = Mo, W), which is in in the solid state indicates that the XeF + cation is a
equilibrium with FXeOSO 2 F and MOF 4 . strong Lewis acid. Nitrogen bases have been shown
Currently, only two examples of cations contain- to displace the anion, forming Lewis acid-base adduct
ing O Xe F linkages are known. The reaction of cations containing N Xe F linkages, e.g., HC N: +
+
−
−
+
+
◦
(CF 3 ) 2 S O with XeF SbF − in HF solvent at −65 C F Xe --F AsF → HC N Xe F + AsF . Suitable
5
6
6
+
results in the species (CF 3 ) 2 S O XeF SbF − (white nitrogen bases that are resistant to oxidation by the
6
solid), which is reported to be stable at −78 C, but is strongly oxidizing XeF cation have been successfully
+
◦
prone to detonate if mechanically disturbed. The salt predicted by choosing bases whose first adiabatic
+
−
CF 3 C(OH)NH AsF reacts with XeF 2 in BrF 5 solvent ionization potentials are greater than or equal to the
2 6
+
by an HF elimination reaction to give the novel Xe O estimated electron affinity of the XeF cation (10.9 eV).
+
bonded CF 3 C(OXeF)NH cation. The thermally unstable, colorless salt HC NXeF AsF −
+
2 6
˚
˚
[Xe F, 1.936(2) A; Xe N, 2.235(3) A] is prepared by
+
reaction of HC N with Xe 2 F AsF − or XeF AsF − in
+
3
6
6
+
anhydrous HF solvent or by reaction of HC NH AsF −
2. Xenon Bonded to Nitrogen 6
with XeF 2 in BrF 5 solvent. Other nitrile adduct cations,
Several ligand groups form compounds containing xenon– RC N XeF + (R = CH 3 ,CH 2 F, CF 3 ,C 2 H 5 ,C 2 F 5 ,
−
nitrogen bonds. The first xenon–nitrogen bonded com- n-C 3 F 7 ,C 6 F 5 ), have been prepared as AsF salts using
6
pound, FXeN(SO 2 F) 2 , was prepared by reaction of methods similar to those used for the preparation of
−
◦
+
HN(SO 2 F) 2 and XeF 2 at 0 CinCF 2 Cl 2 solvent, and HC NXeF AsF . The alkyl and C 6 F 5 derivatives are
6
+
Xe N bonding in this compound was conclusively es- generally thermally less stable than HC NXeF AsF −
6
tablished by X-ray crystallography. The Xe N and Xe F or the perfluorinated alkyl derivatives. The structures of
˚
˚
+
−
bond distances are 2.200(3) and 1.967(3) A, with trig- the H 3 CC NXeF AsF ·HF [Xe F, 1.947(5) A; Xe N,
6
˚
+
onal planar coordination around the nitrogen atom. The 2.179(7) A] and (H 3 C) 3 CC NXeF AsF − [Xe F,
6
˚
˚
compound is a white solid at room temperature, decom- 1.952(3) A; Xe N, 2.212(4) A] salts have also been
posing rapidly and quantitatively at 70 C to XeF 2 , Xe, determined, and the C N Xe angles are found to be
◦
and [N(SO 2 F) 2 ] 2 . The fluoride ion donor properties of significantly bent by 175.0(8) and 166.9(4) degrees,
FXeN(SO 2 F) 2 have been studied by reaction with the respectively. The fluoro(perfluoropyridine)xenon(II)
strong fluoride ion acceptors AsF 5 and SbF 5 . The re- cations 4-RC 5 F 4 N--XeF + (R = F, CF 3 ) have been ob-
action of FXeN(SO 2 F) 2 with AsF 5 results in a yellow served by NMR spectroscopy in HF and BrF 5 solutions
solid, XeN(SO 2 F) AsF , which decomposes at 22 C un- (stable up to −30 C), and their AsF − salts (colorless
−
◦
+
◦
2 6 6
der vacuum to the yellow solid F[XeN(SO 2 F) 2 ] AsF . solids) have been isolated from BrF 5 solutions. Low-
−
+
2 6
The cation consists of two XeN(SO 2 F) 2 groups with pla- temperature Raman and NMR spectroscopic results
nar nitrogen centers joined by a bridging fluorine atom, are consistent with planar cations in which the xenon
+
similar to the Xe 2 F cation (see Section III.E). Crystalline atom is directly bonded to the aromatic ring through
3
+
XeN(SO 2 F) Sb 3 F − has been isolated by dissolution of the lone pair of electrons on the nitrogen atom. The
2 16
XeN(SO 2 F) AsF − in SbF 5 at 0 C. The X-ray crystal fluoro(perfluorodiazine)xenon(II) cations 1,2-C 4 F 4 NN
◦
+
2 6