Nuclear magnetic resonance studies of donor–acceptor interaction in boron halide complexes. Part VI. The relative donor strengths of nitrobenzene and pentafluoronitrobenzene

Abstract

The I l B chemical shifts of either the isolated 1 :I complexes or, in the absence of the formation of solid adducts, the 1 : 1 mixture of the components, have been used to investigate the donor properties of nitro-and pentafluoronitro-benzenes towards boron halides in methylene dichloride solution. The I4N chemical shifts, obtained o n the same solutions, revealed no simple correlation w i t h the donor properties although the resonance line widths reflected the acceptor properties of the boron halides. The lQF chemical shifts of complexes of pentafluoronitrobenzene are also discussed.

Molecular addition compounds. 4. Unusually slow reaction of tertiary amines with 9-borabicyclo[3.3.1]nonane (9-BBN) dimer. New, stable, mildly reactive amine complexes of 9-BBN

“…5 In recent years a number of partially substituted boranes have been prepared and have proved to be highly useful reagents. 6 With few exceptions, such as ieri-butylboranetrimethylamine (2),7,8 phenylborane-pyridine (3), 9 thexylborane-trimethylamine (4),10 and disiamylborane-trimethylamine (5),10 the preparation and the chemistry of the corresponding amine complexes have remained relatively unexplored until recently. However, recent studies in this laboratory have resulted in simple procedures for the preparation of thexylborane-triethylamine (6),11 cyclohexylborane-triethylamine (7), 11,12 DIBborane-TMEDA (8), 13 and isopinocampheylborane-triethylamine (9)14 and have led to the discovery of promising new applications for these derivatives.…”