Exchange of Halide for Miscellaneous Anions

Exchange reactions using triorgano telluronium halides as starting materials produced triorgano telluronium salts with the anions Y identified below. These telluronium salts precipitate when aqueous or ethanolic solutions of the reactants are combined. 

Triphenyl Telluronium Triboranate-8 1.00 g (2.3 mmol) of triphenyl telluronium bromide are dissolved in 100 ml of water and 0.26 g (2.2 mmol) of tetramethyl ammonium triboranate-8 are dissolved in 50 ml of water. The two solutions are cooled to 0° and mixed. The precipitate is filtered off, washed under nitrogen with diethyl ether, and dried in a stream of nitrogen yield 0.83 g (95%) m.p. 57° (dec.). 

Diphenyl Methyl Telluronium Tetrafluoroborate 0.5 g (1.2 mmol) of diphenyl methyl telluronium iodide are dissolved in water. An aqueous solution eontaining 0.23 g (1.2 mmol) of silver tetrafluoroborate is prepared by reacting equivalent amounts of silver oxide and tetrafluoroboric acid. The solutions are mixed, stirred for 1 h at 20°, heated under reflux for 4h, and concentrated. Silver iodide is filtered off and the product crystallized m.p. 135°. 

Similarly prepared were the following triorgano telluronium tetrafluoroborates  

IVimethyl Telluronium Tetrabromoborate 1.69 g (6.7 mmol) of trimethyl telluronium bromide and 15 g (60 mmol) of boron tribromide are mixed in a vacuum line trap, the mixture is stirred magnetically at 20° for 8 h, and excess boron tribromide is then removed to leave the colorless product m.p. 215° (dec.). 

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