Scrambling reactions between boron and various phosphorus moieties: The B(NEt 2) 3/PCl 3, B(NEt 2) 3/OPCl 3 and B(NEt 2) 3/SPCl 3 systems

Abstract

A 31P, 11B and 1H NMR study of the scrambling reactions between tris (diethylamino) boron B[N(C 2H 5) 2] 3 and PCl 3, OPCl 3 and SPCl 3 shows that the mixed species QCl 3− n (NEt 2) n [ Q = B, P, OP or SP and n = 1 or 2] are more favoured than would be the case if a completely random mechanism was involved. In the PCl 3/B[N(C 2H 5) 2] 3 system the chlorine substituents display preferential affinity for phosphorus moieties over boron centers while the reverse situation is encountered in the two other systems involving quadruply coordinated phosphorus. The Lewis acidity of boron and the effective electronegativity of phosphorus moieties may explain these trends.