Xenon—fluorine bonds

Electron Distribution in the Xenon Fluorides and Xenon Oxide Tetrafluoride by ESCA and Evidence for Orbital Independence in the Xenon-Fluorine Bonding... 

T. X. Carroll, R. W. Shaw, T. D. Thomas, C. Kindle and N. Bartlett, Electron Distribution in the Xenon Fluorides and Xenon Oxide Tetrafluoride by ESCA and Evidence for Orbital Independence in the Xenon-Fluorine Bonding, J. Am. Chem. Soc. 96 (1974) 1989-1996. 

The 1 1 adduct (XVIII), a bright yellow solid, is unstable at room temperature while the pale yellow solid 2 1 adduct appears to be stable. Raman spectra show complete absence of v(Xe—F) at 504 cm-1 indicating the absence of terminal xenon-fluorine bonds. The vsym(SO) and vasym(SO) bands are shifted to 1236 and 1494 cm"1, which are higher than those in the neutral molecule, suggesting cation formation. 

Following Bartlett s discovery of xenon hexafluoroplatinate(VI), xenon and fluorine were found to combine to give several volatile, essentially covalent fluorides, and at least one fluoride of krypton has been obtained. From the xenon fluorides, compounds containing xenon-oxygen bonds have been made much of the known chemistry of xenon is set out in Figure 12.1. 

Xenon difluoride fluorinates adamantane in low yield [45] (equation 22) When the carbon-hydrogen bond is activated by an a-sulfur atom, fliiorination occurs readily The reactions involve intermediates that contain sulfur-fluorine bonds. At-Fluoropyridinium reagents behave similarly [99, 100, 101, 102] (equations 55-57)... 

In the past 40 years, compounds have been isolated in which xenon is bonded to several nonmetals (N, C, and Cl) in addition to fluorine and oxygen. In the year 2000, it was reported [Science, Volume 290. page 117) that a compound had been isolated in which a metal atom was bonded to xenon. This compound is a dark red solid stable at temperatures below -40°C it is believed to contain the [AuXe4F+ cation. 

In the following section two aspects are discussed a) the syntheses of fluorinated and non-fluorinated alkynylxenonium salts, [XCsCXe][BF4], and b) the syntheses of polyfluoroalkenylxenonium salts [XCF=CFXe][BF4] and [CF2=CXXe][BF4]. These topics will provide further insight into the fundamental aspects regarding xenon-carbon bond formation. 

To overcome problems associated with the removal of iodobenzene and its derivatives formed upon fluorination of arylalkenes and arylalkynes with (difluoroiodo)arenes, polymer-supported (difluoroiodo)arenes were proposed.139 With these agents, the separation procedures are reduced to filtration of the iodinated polymer. For this purpose popcorn polystyrene is io-dinated and then transformed into the difluoroiodide by treatment with xenon difluoride in the presence of hydrogen fluoride in dichloromelhane at 25 C. The amount of active fluorine bonded to iodine atoms on the polymer support is estimated by iodometric titration. The reactions with phenyl-substituted alkenes result in rearranged gew-difluorides. The procedure provides the same fluorination products as with (difluoroiodo)benzenc (see Section 4.13.) but in much higher yields, e.g. PhCF2CH2Ph (96%), PhCF2CH(Me)Ph (95%). PhCH2CF2H (86%), and l,l-difluoro-2-phenylcyclopentanc (91 %). 

On page 835 it is stated that xenon forms bonds with only the most electronegative elements such as the very active fluorine and oxygen. How can you reconcile this with Ihe formation of the Xc—Xe bond in Xe Winr Rethink Problem 5.15.J... 

Xenon-carbon bond formation is now quite well exemplified, and many products contain fluorinated aryl substituents, e.g. (C6F5C02)Xe(C6F5), [(2,6-F2C5H3N)XeC6F5]+ (Figure 17.7a), [(2,6-F2C6H3)Xe][Bp4] (Figure 17.7b), [(2,6-... 

In 1989, two groups working independently prepared pentafluoro-phenylxenon borates by nucleophilic displacement of fluorine in XeFa using BiCeFs), as an aryl-transfer reagent. The resulting colorless solid, which has a stable xenon-carbon bond, was characterized in solution by Xe and F NMR [e.g., Eq. (22)] (165, 166) ... 

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