The Molecular Structure of 1,3,5,7- Tetra(tert-butyl)-2,4,6,8-tetraazidoborazocine [1]

Abstract

The tetra(tert-butyl)-tetraazido-borazocine, 1, has the expected tub shape as determined for (SCNB=NtBu) 4 . However, it crystallizes in the triclinic system and shows no symmetry element in contrast to the isothiocyanato derivate which has C 2 symmetry. There are two kinds of BN bonds which alter from long to short (average 1.491 and 1.388Å). The BN bond lengths to the azido groups are, on average, 1.486Å. All B and N atoms of the ring reside in a trigonal planar environment. The B-N-N bond angles are close to 120 • showing that the central nitrogen atom can be considered as sp 2 -hybridized. The N-N-N bond angles are on average 173.6 • . The two sets of the opposite B 2 N 2 planes include an angle of 114.8 • . The atoms of the azido groups are almost coplanar with the respective NBN planes. This together with the short BN(N 2 ) bond lengths indicates that these azido groups are π-bonded to their corresponding boron atom.