Bernd Wilkes

Vergleich der trifluormethylierungseigenschaften von(CF3)Hg, CF3I und (CF3)2te am beispiel der reaktionen mit cyclohexen, benzol und pyridin

Abstract The trifluoromethylation reactions of (CF 3 ) 2 Hg, CF 3 I and (CF 3 ) 2 Te with cyclohexene, benzene and pyridine are compared under similar conditions. Photochemical as well as thermal reactions result in an increase of the reactivity in the series (CF 3 ) 2 Hg 3 I ⪡ (CF 3 )2Te. The yields and the kind of products vary depending on the time of irradiation and the temperature. In all cases the best yields are obtained from the thermal reactions with (CF 3 ) 2 Te. With cyclohexene only trifluoromethylated addition products are observed. The substitution reactions with pyridine yield a mixture of isomeric trifluoromethylpyridines. (CF 3 ) 2 Hg and CF 3 I react with benzene to yield only benzotrifluoride C 6 H 5 CF 3 . The main product of the reaction of (CF 3 )2Te with benzene is also benzotrifluoride; in addition to this the disubstituted bis(trifluoromethyl)benzene isomers and trifluoromethyl- cyclohexadienes are formed. 1 H, 19 F n.m.r. and mass spectra are described.

Tetrakis(trifluormethyl)tellur (CF3)4Te [1]

Abstract (CF 3 ) 4 Te is formed from the reaction of (CF 3 ) 2 TeCl 2 with (CF 3 ) 2 Cd·glyme in CH 3 CN at −10°C via the intermediate (CF 3 ) 3 TeCl as a yellow liquid and identified by n.m.r. and mass spectra.

Preparations and properties of tetrakis(perfluoroorgano)-tellurium compounds

Abstract (CF 3 ) 4 Te is the first chalcogen compound with more than two CF 3 groups. It is formed from the reaction of equivalent amounts of (CF 3 ) 2 TeCl 2 and (CF 3 ) 2 Cd·glyme [1]: (CF 3 ) 3 TeCl is detected as an intermediate. (CF 3 ) 4 Te is a decomposable yellow liquid (m.p. ca. −45 °C). The photolysis in the presence of cyclohexene yields C 6 H 10 (CF 3 ) 2 , C 6 H 10 (CF 3 )(TeCF 3 ) and some decomposition compounds. During the thermal decomposition also |CF 2 is formed. (CF 3 ) 4 Te has amphoteric properties: All these reactions and the spectra of the new compounds as well as some experiments to prepare other tetrakis(perfluoroorgano)Tellurium compounds are discussed.

Preparation and properties of trifluoromethyl tellurium compounds, part II

Abstract The reactions of bis(trifluoromethyl)tellurium and bis(trifluoromethyl) tellurium dihalides with Lewis acids and bases are reported. Bis(trifluoromethyl)tellurium dihalides react with Lewis acids AX and Lewis bases MX to yield the corresponding salts, as shown in the following scheme: As F 5 oxidizes (CF 3 ) 2 Te in a first step to (CF 3 ) 2 TeF 2 , which in a second step reacts with an excess of AsF 5 to form the salt [(CF 3 ) 2 TeF][AsFe 6 ]. The reactions of (CF 3 ) 2 Te with alkali halides yield 1:1 complexes. The chemical properties as well as the 19 F n.m.r., the Raman and the IR spectra of the new compounds will be described and compared with the corresponding iodine compounds.