Darstellung und 11B-NMR-Spektrum von Heptabromo-closo-heptaborat, [B7Br7]2- sowie Kristallstruktur von [(C5H5N)2CH2][B7Br7] / Preparation and 11B NMR Spectrum of Heptabromo-closo-heptaborate, [B7Br7]2-, and the Crystal Structure of [(C5H5N)2CH2][B7Br7

Abstract

By reaction of conjuncto-[B6H6-B6H6]2- in alkaline solution with excess bromine the heptabromo-closo-heptaborate, [B7Br7]2 is formed. The crystal structure of [(CsH3N)2CH2][B7Br7] has been determined by single crystal X-ray diffraction analysis (monoclinic, space group P21/a with a = 15.0843(14), b = 9.8882(14), c = 17.057(2) Å, β = 114.039°(7)). In accordance with the D5h point symmetry, the anion shows two singlets at -23.3 and -0.1 ppm with the intensity ratio 2:5 in its 11B NMR spectrum.