Monofluoroxenonium hexafluorometalates

It is very likely that XeF AsF5" occurs as a reactive intermediate in equation 7. We decided to test this idea by carrying out a number of direct reactions of the monofluoroxenonium hexafluorometalates XeF+AsF5" and XeF+SbF ", both of which can be readily obtained by reaction of XeF2 with MF5 (M = As, Sb) in HF (equation 8) (8). We first studied the fluorination of the alkyl and perfluoroalkyl... 

The next logical step was the extension of this chemistry to SH derivatives. Attempts to oxidatively fluorinate CF3SSH with monofluoroxenonium hexafluorometalates failed, even at 195 K. Only decomposition into the already mentioned Sg + salts could be observed (24). On the other hand, the synthesis of the fluoro(trifluoromethyl)sulfonium- and fluoro(methyl)sulfonium cations from the SH acidic sulfanes CF3SH and CH3SH proceeded without difficulty at 213 K (Figure 1) (25). The elimination of HF at 213 K is expected to be preferred from a thermodynamic point of view, although HF elimination is probably kinetically inhibited in this case. However, at 233 K decomposition of all of these compoimds into the characteristic blue Sg2+ salts is observed. By reaction with chlorine... 

The reactions described in this paper have shown that a number of different molecules can be prepared by the use of the monofluoroxenonium hexafluorometalates. These salts are extremely mild and regioselective agents for oxidative fluorination. Thus, the synthetic potential of XeF+MF6" (M = As, Sb) offers the possibility to obtain monofluorinated onium salts as well as compounds containing an E-XeF element bond or even polyhalonium cations. It is clear that many unexpected results remain to be discovered in this area. 

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