A Simple and Convenient Route to Arylxenon(II) Tetrafluoroborates

Abstract

An improved synthesis of arylxenon(II) salts is reported. The series of fluoro-containing arylxenon(II) tetrafluoroborates (aryl = C6F5, 2,3,4,5-C6HF4, 3,4,5-C6H2F3 and 3,5-CöH3F2) are prepared by the reaction of xenon difluoride with the corresponding aryldifluoroboranes. The salts [CöFsXe] [BF4] and [2,3,4,5-C6HF4Xe] [BF4] are long-term stable in anhydrous HF (aHF) solution at rt, while [3,4,5-C6H2F3Xe] [BF4] and [3 ,5-C6H3F2Xe] [BF4] are convertedinto 1,2,3,5-tetrafluorobenzene and 1,3,5-trifluorobenzene, respectively, within a few hours.

C6F5XeF, a versatile starting material in xenon–carbon chemistry

“…In CH 2 Cl 2 , no reaction was detected by 19 F NMR at À78 8C. The stepwise heating of the mixture up to À10 8C followed by cooling to À78 8C was accompanied by the complete consumption of dialkylcadmium.…”

“…[2,4,6-C 6 H 2 F 3 Xe] [BF 4 ] was prepared analogous to the method described in [19] by the reaction of XeF 2 and 2,4,6-C 6 H 2 F 3 BF 2 and [NMe 4 ] F was obtained similar to lit [20].…”

“…The 1 (0.10 mmol), C 6 F 5 SiMe 3 (0.09 mmol), and [NMe 4 ] F (3 mg, 0.03 mmol) together in 1.9 ml CH 2 Cl 2 (À78 8C) were stirred and formed a suspension. 19 NMR control showed that C 6 F 5 SiMe 3 had reacted totally. The molar ratio of C 6 F 5 compounds in the mother liquor was 1:2:C 6 HF 5 :(C 6 F 5 ) 2 ¼ 1:2:4:2.…”

“…[C 6 F 5 Xe] [C 6 F 5 BF 3 ] was formed in approximately 90% yield. 19 4.2.5. The reaction of C 6 F 5 XeF with Cd(2,4,6-C 6 H 2 F 3 ) 2 2,4,6-C 6 H 2 F 3 XeC 6 F 5 (4) was obtained by using the procedure described in Section 4.2.1 starting with C 6 F 5 XeF (0.08 mmol, determined by the quantitative NMR standard C 6 F 6 ) in 0.7 ml CD 2 Cl 2 and Cd(2,4,6-C 6 H 2 F 3 ) 2 (16 mg, 0.04 mmol) in 0.3 ml CD 2 Cl 2 .…”

“…The reaction of C 6 F 5 XeF with perfluoroethenyltrimethylsilane A cold CH 2 Cl 2 solution (À78 8C, 0.2 ml) of CF 2 ¼ CFSiMe 3 (0.02 mmol, containing an admixture of hexane) was added to a stirred CH 2 Cl 2 solution (À78 8C, 1 ml) of 1 (0.08 mmol). 19 F NMR control after 1 h indicated that no reaction had proceeded. After the addition of [NMe 4 ] F (5 mg, 0.05 mmol) dissolved in cold CH 2 Cl 2 (À78 8C, 0.5 ml) the mixture changed the colour to brown and the 19 F NMR displayed the consumption of the starting materials and formation of the products 2, CF 2 ¼ CFÀH, C 6 HF 5 , (C 6 F 5 ) 2 , and Me 3 SiF in the molar ratio 5:40:5:1:60.…”