Contributions to bis(perfluoroalkyl) chalkogenide chemistry: preparation of (Rf)2SeO [Rf = C2F5, (CF3)2CF, n-C4F9], (Rf′)2TeX2 [X = F, Cl: Rf′ = n-C3F7, (CF3)2CF, n-C4F9; X = Br: Rf′ = n-C3F7, n-C4F9], (CF3)2Te(NSO)2 and (C2F5)2Te(OH)NO3

The reaction between perfluoroalkyl iodides with a threefold excess of a 1 : 1 molar mixture of Se and Cu is a new method for the preparation of corresponding monoselenides (1a–c) and diselenides (2a–d). They are oxidised with HOF without a solvent to bis(perfluoroalkyl) selenium(IV) oxides (3a–d). Halogenation of (Rf)2Te with XeF2, Cl2 or Br2 yielded (Rf)2TeF2 (7a–c), (Rf)2TeCl2 (8a–c) and (Rf′)2TeBr2 (9a, 9c). Oxidation of (C2F5)2Te with conc. HNO3 gave (C2F5)2Te(OH)NO3 (4). When (CF3)2TeCl2 is treated with AgNSO metathesis took place forming (CF3)2Te(NSO)2 (6). Two (C6F5)2Te(VI) derivatives with the general formula (C6F5)2TeX4 with X = CF3C(O)O (5) and F are made from (C6F5)2TeO2 and CF3C(O)OH or SF4, respectively. The monotelluride (n-C6F13)2Te was synthesised similarly from n-C6F13I, Te and Cu. X-ray structures for 3d, 8a, and 8b are provided.