Trimethylamine-monobromoborane

The addition compound of trimethylamine and monobromo-borane has been prepared by reaction of trimethylamine-borane with either bromine or boron tribromide,4 but an excess of either reagent gives further bromination. Hydrogen bromide, however, gives only the monobromo derivative, even when added in excess. The synthesis is similar to that of trimethylamine- 

The solution turns light pink at this point. 

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