Oxidative Fluorination of Selenium and Tellurium Compounds using a Thermally Stable Phosphonium SF₅⁻Salt Accessible from SF₆

Abstract

Fluorinated group 16 moieties are attractive building blocks in synthetic chemistry but only few synthetic methods are available to prepare them. Herein, we report a new oxidative fluorination reagent capable of stabilizing reactive fluorinated anions. It consists of an SF 5 À anion and a chemically inert phosphonium cation and is exceptionally thermally stable. Accordingly, it was used to generate the SeF 5 À and TeF 5À anions from the elemental chalcogens and to prepare the unknown tetrafluoro(phenyl)-λ 5 -selenate PhSeF 4À and -tellurate PhTeF 4 À from the corresponding diphenyl dichalcogenides. In addition, we show that further derivatization of [PhTeF 4 ] À by oxidation to trans-PhTeF 4 O À and subsequent alkylation gives access to a new class of trans-(alkoxy)(phenyl)tetrafluoro-λ 6 -tellanes (trans-PhTeF 4 OR), thus providing an approach to introduce the functional group into organic molecules.

Activation of SF5CF3 by the N-Heterocyclic Carbene SIMes

“…Analytical data for 9: 19 F NMR (282.4 MHz, C 6 D 6 ): δ = −55.6 (t, 3 J FF = 10.2 Hz) ppm, GC-MS (C 6 D 6 ): calculated (m/z) for [9]: 248.08, experimental (m/z) for [9]: 248. The obtained NMR data are consistent with those in the literature [46,47].…”

“…The greenhouse gases SF 5 CF 3 and SF 6 are both chemically highly inert and have a long atmospheric lifetime [1][2][3]. Whereas the activation of SF 6 has been well established in the last decade [4][5][6][7][8][9][10][11][12][13][14][15][16][17], the studies on SF 5 CF 3 are rare. Dresdner et al published the reaction of SF 5 CF 3 with perfluoropropylene at temperatures of 425 • C-513 • C to give perfluoroethane and SF 4 [18][19][20].…”