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MeTeRf (Rf = CF3, C2F5) can easily be prepared via the reactions of methyl iodide and the corresponding tetramethylammonium perfluoroalkyltellurates(0), [NMe4]TeRf (Rf = CF3, C2F5). Both compounds are easily oxidized by xenon difluoride and the heavier halogens to yield the corresponding dihalides, MeTe(Rf)X2 (X = F, Cl, Br, I) and by ArI(OCOCF3)2 to give the corresponding trifluoroacetates, MeTe(Rf)(OCOCF3)2. All compounds are characterized byspectroscopic means. The molecular structures of MeTe(Rf)F2,MeTe(Rf)Cl2, MeTe(Rf)Br2, and of 4-MeC6H4I(OCOCF3)2 were elucidated by XRD methods.

The reactions of non-activated aldimines with trimethyl(trifluoromethyl)silane and 1 equiv. of tetramethylammonium fluoride proceed via the formation of tetramethylammonium amides which were identified by low-temperature 19F NMR experiments. Consecutive reactions of the salts formed in situ with electrophiles yielded trifluoromethylated amines. Fluoride elimination is observed in the absence of electrophilic substrates leading to the formation of difluoromethylated ketimines.

Trifluoromethylketones of aromatics, heteroaromatics and olefins are formed selectively from reactions of trifluoromethylsilver and the corresponding carboxylic acid chlorides in moderate to excellent yields. The conditions chosen are dependent on the nature of the acyl chloride. Attempts to prepare alkyl(trifluoromethyl)ketones yielded product mixtures of the corresponding acyl fluorides, trifluoromethyl-, pentafluoroethyl- and n -heptafluoropropyl ketones.

The reaction of the sterically shielded phosphane derivative, dichlorodiethylaminophosphane, Cl2PNEt2, with an excess of a mixture of 2,6-bis(trifluoromethyl) and 2,4-bis(trifluoromethyl)phenyl lithium gives bis[2,4-bis(trifluoromethyl)phenyl]diethylaminophosphane, [2,4-(CF3)2C6H3]2PNEt2, in 72 % yield as a colourless solid, while 2,6-bis(trifluoromethyl)phenyl lithium remains unchanged in solution. The amino derivative crystallizes in the monoclinic space group P21/c (a 869.2(1), b 1857.4(1), c 1357.6(1) pm, β 100.57(4)°, Z = 4). Treatment of [2,4-(CF3)2C6H3]2PNEt2 in CHCl3 solution with conc. HCl allows the synthesis of [2,4-(CF3)2C6H3)]2PCl. [2,4-(CF3)2C6H3]2PCl reacts with H2O in THF solution with quantitative formation of the corresponding secondary phosphane oxide. To obtain bis[2,4-bis(trifluoromethyl)phenyl]phosphinic acid, [2,4-(CF3)2C6H3]2P(O)OH, quantitatively, a CHCl3 solution of [2,4-(CF3)2C6H3]2P(O)H, has to be stirred in an NO2 atmosphere. The phosphinic acid crystallizes is the triclinic space group (a 754.2(1), b 927.6(2), c 1305.5(2) pm, α 85.11(2)°, β 75.45(1)°, γ 79.99(2)°, Z = 2). From the reaction of the phosphinic acid with either elemental sodium or with cyanide salts, the corresponding phosphinate salts are obtained in an almost quantitatively yield.

The anions [(TeCF3)2X]− (X = Cl, Br, I) resemble the trihalides [I2X]− in the solid state and show similar dynamic behaviour in solution. All three compounds crystallize iso-structurally in the triclinic space group with Z = 2 and exhibit cell dimensions according to the sizes of the halogen atoms.

A complete series of compounds with the anions [(TeCF3)(3-x)I(x)]- (x = 0-2) had been prepared and characterised in the solid state and by NMR spectroscopic methods. Dynamic behaviour in solution can be assumed for [(TeCF3)3]- and [(TeCF3)2I]-, while in the solid state all three bis(triphenylphosphoranyliden)ammonium (PNP) salts resemble structures found in triiodides. The molecular structures of [PNP][(TeCF3)(3-x)I(x)]- (x = 0-2) are discussed in comparison with [PNP]I3, I2, and Te2(CF3)2. On this basis, the structures of the [(TeCF3)3]- and [(TeCF3)I2]- ions are comparable to symmetric I3- ions, while the [(TeCF3)2I]- ion resembles an asymmetric I3- unit.

Convenient procedures for the synthesis of the title compounds and for the preparation of a variety of 2,4,6-tris(fluorosulfonyl)phenolates are presented.

Tetrakis(pentafluorophenyl)tellurium(IV), Te(C6F5)4 ,w as prepared from the reaction of TeCl4 and Mg(C6F5)Br. Crystalliza- tion of the crude product from n-pentane at 25 °C gave suitable single crystals. The title compound crystallizes in the monoclinic Our investigations of perfluoroorganotellurium compounds in dif- ferent oxidation states (1) allowed us during the last decades to give new insights into the manifold chemistry and structural diversity of perfluoroorganotellurium compounds. Among the numerous compounds structurally characterized so far, those of pentafluoro- phenyl derivatives are best investigated. Some molecular structures of bis(pentafluorophenyl)tellurium(IV) derivatives (25), covalent tris(pentafluorophenyl)- (5, 6) and one salt-like tris(pentafluoro- phenyl)tellurium(IV) derivative (5) have been elucidated, while the parent molecule, Te(C6F5)4, was only characterized by spectro- scopic methods in solution. Herein, we report the results of XRD investigations of Te(C6F5)4, a further example of a tellurium(IV) species with four Te-C bonds.