Darstellung,11B-NMR- und Schwingungsspektren isomerenreiner Halogenohydrodecaborate XnB10H10- n 2-; X = Cl, Br, I; n = 1, 2 / Preparation, 11B NMR and Vibrational Spectra of Pure Isomeric Halohydrodecaborates XnB10H10- n 2-; X = Cl, Br, I; n = 1, 2

Abstract

Pure isomers of XnB10H10-n 2-; X = Cl, Br, I; n = 1, 2; are isolated by ion exchange chromatography on diethylaminoethylcellulose. Their structures are determined by11B and 11B {1H }NMR spectroscopy. There are characteristic chemical shifts due to apical and equatorial substituents, respectively. The highest field signals are explained by the antipodal effect. In contrast to theoretical predictions the experimental investigations show, that the successive electrophilic substitution preferably occurs on equatorial and not on apical B atoms. IR and Ram an spectra of the 2-XB10H9 2-species are very similar in the ν(BH) and in the B10- cage absorption region. In the far infrared there are two characteristic bands, shifting to lower frequencies in the series Cl, Br, I, which are therefore assigned to (B10) - X stretching and (B10) - X deformation modes.