Boron halides as reagents in inorganic syntheses. Part I. A general method for the preparation of anhydrous bromides and oxybromides, and a comment on reactions with elemental sulphur
Abstract
The reaction between boron tribomide and metal, metalloid, and non-metal oxides (and sulphides) appears to offer a general method for preparing anhydrous bromides and oxybromides. It has been demonstrated for (i) As2O3, As2S3, Sb2S3, and TiO2(which give corresponding bromides), (ii) As2O5, As2S5, and Sb2O5(which give bromides in a lower oxidation state), (iii) P2O5 and WO3(which give corresponding oxybromides), and (iv) V2O5(which gives the reduced oxybromide, VOBr2). The reactions are carried out under reflux, the conversions are essentially quantitative, and separation of pure products is readily achieved.
Interaction of sulphur and dibromophenylborane, C6H5BBr2, gave a member of a new cyclic system.