Triphenylcarbenium perchlorate

Direct oxidation of diphenylmethanes is of little practical value as color formers. In liquid sulfur dioxide, leuco diphenylmethane 12 (Scheme 2) undergoes hydride abstraction by triphenylcarbenium perchlorate at the benzylic amine position to form immonium ion7 13, whereas in acetonitrile... 

Benzotellurin and triphenylcarbenium perchlorate in refluxing trifluoroacetic acid... 

Refluxing telluraxanthenes with triphenylcarbenium perchlorate in trifluoroacetic acid produced telluraxanthylium perchlorates3. 

Methylphenyl)-telluraxanthyliuin Perchlorate3 A mixture of 1.54g (5 mmol) of 9-(4-mcthylphenyl)-telluraxanthenc and 1.88 g (5.5 mmol) of triphenylcarbenium perchlorate in 30 ml of trifluoroacetic acid is heated under reflux for 30 min. The cooled mixture is diluted with 50 ml of absolute diethyl ether, and the precipitate is filtered, washed with three 50 ml portions of absolute diethyl ether, and dried in air yield 2.0 g (100%) m.p. 160° (dec. explosion). 

Addition of perchloric acid or triphenylcarbenium perchlorate to solutions of 9-hydroxytelluraxanthenes formed dark blue telluraxanthylium perchlorates in almost quantitative yields3,4. 

During the 80s and early 90s, Lambert and co-workers reported a number of experiments, which, according to the authors, suggested the existence of free silylium ions in solution. [80-84] The alleged silylium ions were prepared by hydride abstraction from an alkylsilane with triphenylcarbenium perchlorate according to reaction (2) first suggested by Corey. [85]... 

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