Phosphinothioic bromide

The reaction between the thiophosphorus(III) amide 21 and benzyl bromide is of interest in that it is possible to isolate a pseudoquatemary salt 22, which decomposes at just above its melting point (92-93 °C) to give the corresponding phosphinothioic amide (23). ... 

A similar sequence of reactions was described to account for the behaviour of the same phosphinothioate ester with bromine or with iodine The intermediates including, for the brominolysis, those with two phosphorus atoms appeared to be more stable at room temperature. In the case of iodination, no phosphinic iodide was formed, and the only products that were detected were the ester-iodine complex(es) and the iodide of 146 further reaction, which took 1-2 months, gave the thiopyrophosphinate 148 complexed with iodine, as in 149. The bromination reaction was also slow, and although the complex 149 (X = Br) could readily be detected during shorter reaction periods, di- rNbutylphosphinic bromide was obtainable in yields of about 30% only when admixed S -methyl di-f r -butylphosphinothioate and bromine were stored at room temperature for about 2 months. 

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