Crystallographic studies of the boron–nitrogen bond in aminoboranes. Part III. Crystal and molecular structure of tri-(1,3,2-benzodioxaborol-2-yl)amine

Abstract

Crystals of tri-(1,3,2-benzodioxaborol-2-yl)amine (o-C₆H₄·O₂B)₃N are monoclinic, a= 13·15, b= 5·78, c= 11·15 Å, β= 100·04°, space group P2₁ with Z= 2. The atomic positions have been determined by least-squares refinement from X-ray diffraction data. The molecule is planar with the approximate symmetry D_3h(m2). Mean bond lengths are: B-N 1·438, B–01·381, C–01·389, and C–C1·388 Å. The molecular structure is discussed on the basis of a π-bond system covering the whole molecule apart from the hydrogen atoms and a B-N bond order of 1·4 is deduced from molecular-orbital calculations.