Structural studies of organoboron compounds. XIV. Preparation and crystal and molecular structure of 4-isopropylidene-2,5,5-triphenyl-1,3-dioxa-4-azonia-2-bora-5-boratacyclopentane

Abstract

Details of the synthesis, physical properties, and molecular structure of 4-isopropylidene-2,5,5-triphenyl-1,3-dioxa-4-azonia-2-bora-5-boratacyclopentane are reported. Crystals of this compound are monoclinic, a = 14.126(3), b = 16.008(1), c = 8.642(2) Å, β = 99.052(8)°, Z = 4, space group P21/n. The structure was solved by direct methods and was refined by full-matrix least-squares procedures to R = 0.032 and Rw = 0.033 for 1117 reflections with I ≥ 3σ(I). The molecule contains a nearly planar five-membered B—O—B—O—N ring which incorporates both trigonal planar boron (B—O = 1.333(4) and 418(4), B—C = 1.548(5) Å) and tetrahedral boron atoms (B—O = 1.495(4), B—N = 1.676(4), B—C = 2 at 1.603(5) Å). Other important libration-corrected bond distances include: C=N = 1.284(3) and N—O = 1.418(3) Å.