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.