Tellurium, trifluoromethyl compounds

With the exception of the reactions of trifluoromethyl radicals with sulfur vapor, which is really a separate class of reactions, if the power supplied to the load coil surrounding the reactor (see Fig. 2) was maintained at, or near, the minimum amount needed to support the discharge, in only two cases were compounds found that clearly resulted from reactions other than replacement of halogen by trifluoromethyl. The reaction of tellurium tetrabromide (or the chloride) gave, in addition to the products just reported, very small proportions of such species as BrCF2TeCF2Br and (C2F5)2Te, which were isolated in yields of... 

Removal of the volatile t-butyldimethylchlorosilane from a mixture of chloro-tris[trifluoromethyl] germane and bis[t-butyldimethyIsilyl] tellurium that had been kept at 80° for two days gave bis[tris(trifluoromethyl)germyl] tellurium in 52% yield. The compound can be stored at — 80° without decomposition5. 

Tellurium, evaporated from a crucible, reacted with trifluoromethylthio radicals, generated from bis[trifluoromethyl] disulfane in a radio-frequency glow discharge, in a vessel equipped with a cold finger chilled with liquid nitrogen and evacuated to 0.001 torr. Trap-to-trap distillation of the material that condensed in the cold finger produced bis[trifluoromethylthio tellurium. The thermally unstable compound condensed in the - 45° trap4. 

Chloro(trifluoromethyl)methyleneamino tellurium pentafluoride was similarly prepared2 from tellurium chloride pentafluoride and trifluoromethyl cyanide. The product could be purified only by preparative gas chromatography on a 15% Halocarbon K-352 column. The vapor pressure of the pure compound was 50 torr at 25°. 

Pyrolysis of potassium pentafluorotelluro(trifluoromethyl)amide produced difluoromethy-leneamino tellurium pentafluoride. This compound did not isomerize to trifluoromethyl-imino tellurium tetrafluoride2,3. 

The selective alkylation of tellurium tetrachloride10 and tetrabromide11 to a diorgano tellurium compound was achieved with bis[trifluoromethyl] mercury10 11 and the bipyridyl adduct of bis[pentafluoroethyl] mercury11. 

In the reaction between tellurium tetrachloride and bis[trifluoromethyl] mercury, the following compounds were also formed1 chlorine, dichlorodifluoromethane, cklorodi-fluoromethyl trifluoromethyl tellurium, and bis[chlorodifiuoromethyl tellurium... 

Neat dimethyl tellurium and trifluoromethyl iodide or pentafluoroethyl iodide reacted under UV irradiation to give bis[perfluoroalkyl] telluriums and methyl perfluoroalkyl telluriums. The bis[perfluoroalkyl] telluriums could not be completely separated from the unsymmetrical tellurium compounds by trap-to-trap distillation. The yields are strongly influenced by the molar ratios of the reactants. The products were isolated as yellow, odorless liquids3. 

Bis[trifluoromethyl] Tellurium Dinitrate8 A 10% solution of bisftrifluoromethyl] tellurium in fluorotrichlo-romethane is cooled to — 100° under nitrogen. A solution of chlorine nitrate (5-fold molar excess) in fluorotrichloromethane is slowly added dropwise to the solution of the tellurium compound. The mixture is allowed to slowly warm to — 78° and the solvent is evaporated at this temperature. The white, moisture-sensitive product decomposes with evolution of nitrogen oxides above — 20° m.p. — 22° (in a sealed tube). 

A bomb tube containing bis[trifluoromethyl] tellurium difluoride was cooled to — 196°. Excess boron trifluoride was condensed to the tellurium compound. The tube was sealed and shaken at 20° for three days. The tube was carefully opened and the excess boron trifluoride distilled from the reaction mixture at low temperature1. 

These compounds are easily hydrolyzed and decompose at temperatures above — 15°. They are soluble in polar solvents. Reactions between bis[trifluoromethyl] tellurium dichloride or dibromide with boron trihalides or aluminum trihalides resulted in decomposition1. 

Dimethyl ditellurium is formed when methyl radicals, generated by thermal decomposition of methane butane, diethyl ether, or dimethyl ether interact with tellurium mirrors. Because dimethyl ditellurium can be prepared more conveniently by other methods, these reactions are not of synthetic importance. However, this reaction is one of the two ways to prepare bis[trifluoromethyl] ditellurium. Thus, this compound was prepared through interaction of trifluoromethyl radicals with tellurium tetrachloride , tellurium tetrabromide " or tellurium "... 

Bis[trifluoromethyl] tellurium and bis[pentafluorophenyl] tellurium react with dimethyl zinc or dimethyl eadmium with stepwise replacement of the perfluoroorganyl groups by methyl groups These reactions were carried out in trichloroliluoromethane in the presenee of bis[2-ethoxyethyl] ether as the complexing agent for the perfluoroorgano element compounds. ... 

The diorgano tellurium dicarboxylates are white, crystalline materials that are soluble in organic solvents and stable towards atmospheric agents. Diaryl tellurium diacetates can be boiled in water without decomposition. However, bis[trifluoromethyl] tellurium bis trifluoroacetate] was reported to be moisture-sensitive. Aqueous sodium hydroxide converts diaryl tellurium dicarboxylates to diaryl tellurium oxides or dihydroxides . Thermal gravimetric analysis of diaryl tellurium dicarboxylates indicated that these compounds lose carbon dioxide at 240-260° and form the tetraaryl tellurium derivatives. The tetraorgano tellurium compounds decompose slowly to the diaryl tellurium compounds and hydrocarbons. ... 

Among a series of trifluoromethyl dibenzoheterocyclic onium salts derived from chalcogens, a small number of tellurium compounds have been prepared. As electrophilic trifluoromethylating agents, the tellurium compounds appeared as the least reactive. With a very reactive carbanion, the unsubstituted dibenzotellurophenium salt (81) gave only 9% of the trifluoromethylated product. With the p-diketone enolate, (81) did not react. However, the 3,7-dinitrotellurophenium salt (82) showed a relative activity similar to that of the unsubstituted selenium compound (47). 1... 

Contents Trifluoromethyl Aromatic Compounds (R. Filler) Aliphatic Fluoro-amino Acids (F. Loncrini and R. Filler) Fluoro-alcohols (S. K. De and S. R. Palit) Polyfluoroaromatic Derivatives of Metals and Metalloids (S. C. Cohen and A. G. Massey) The Chemistry of Organic Nitrogen Fluorides (J. P. Freeman) Fluorine Compounds of lenium and Tellurium (B. Cohen and R. D. Peacock) Madelung Constants as a New Guide in the Structural Chemistry of Solids (R. Hoppe). 

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