Crystallographic studies of the boron–nitrogen bond in aminoboranes. Part II. Crystal structure of (dimethylamino) dimethylborane at –95°C

Abstract

(Dimethylamino)dimethylborane crystals are orthorhombic, a= 12·4, b= 24·2, c= 4·1 Å, space group Pn2₁a, Z= 8. The atomic positions have been determined from X-ray diffraction data recorded at –95°C. The structure contains two symmetry-independent molecules which are both almost planar (excluding the hydrogen atoms). The molecular symmetry is close to mm2 (C_2v). The mean length of the B–N bond, 1·42 (σ= 0·03)Å, and the planarity of the molecules suggest π-bonding between the boron and nitrogen atoms and a B–N bond order of 1·6 has been deduced from molecular orbital calculations. Other mean bond lengths are: C–N 1·44 (σ= 0·02), C–B 1·65 (σ= 0·02)Å.