Structural studies of organoboron compounds. XXX. 1,9-Dimethyl-3,5,7-triphenyl-2,4,6,8-tetraoxa-1,9-diazonia-5-bora-3,7- diboratatricyclo[5.4.0.03,9]undecane
Details of the preparation and physical properties of the title compound are given. Crystals of 1,9-dimethyl-3,5,7- triphenyl-2,4,6,8-tetraoxa-1,9-diazonia-5-bora-3,7-diboratatricyclo[5.4.0.03,9]undecane are orthorhombic, a = 9.4026(3), b = 9.4663(2), c = 24.7462(9) Å, Z = 4, space group P212121. The structure was solved by direct methods and was refined by full-matrix least-squares procedures to R = 0.036 and Rw = 0.038 for 1536 reflections with I ≥ 3σ(I). The three six-membered and two seven-membered rings comprising the tricyclo[5.4.0.03,9]undecane ring system all have boat or boat-like conformations. Important bond lengths (corrected for libration) are: B(sp3)—N = 1.649(6) and 1.668(6), B(sp3)—O(N) = 1.492(5) and 1.497(6), B(sp3)—O[B(sp2)] = 1.444(6) and 1.438(5), B(sp3)—C = 1.600(6) and 1.594(7), B(sp2)—O = 1.357(6) and 1.370(6), B(sp2)—C = 1.574(6) Å.