Crystallographic studies of the boron–nitrogen bond in aminoboranes. Part IV. Crystal and molecular structure of (diphenylmethyleneamino)dimesitylborane

Abstract

Crystals of the title compound are orthorhombic, a= 17·36, b= 29·25, c= 10·12 Å, space group Pbca, Z= 8. Their structure was determined from diffractometer X-ray intensity data by direct methods and refined by full-matrix least squares to R 0·078 for 608 reflexions. The B[graphic omitted]NC system in the molecule has an allene-type geometry with B[graphic omitted]N 1·38(2), CN 1·29(2)Å, and a B–N–C of 173(2)°. Bond orders obtained by MO calculations are: B[graphic omitted]N 1·6, CN 1·8. The mean B–C bond length is 1·59(2)Å. The mesityl and phenyl groups are rotated from the position eclipsed with the B[graphic omitted]N or CN bonds, the torsion angles being: C–C–B–N –51 and –65, and C–C–C–N 29 and 50°.