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Published on: May 27, 2020
Indirect nuclear spin-spin coupling constants in 1,2-diboretane-3-ylidene, a homoaromatic system with pi and sigma
Bernd Wrackmeyer1, Armin Berndt
1Anorganische Chemie II, Universität Bayreuth, D-95440 Bayreuth, Germany. b.wrack@uni-bayreuth.de
Abstract:
The non-classical 1,2-diboretane-3-ylidene 1a was studied by 13C and 29Si NMR spectroscopy in order to obtain coupling constants 1J(13C,11B) and 1J(29Si,13C). The magnitudes of 1J(13C,11B) were deduced from linewidth measurements in low-temperature 13C and 11B NMR spectra. Calculation of the coupling constants for model compounds related to 1a, using DFT methods based on optimized geometries [B3LYP/6-311+G(d,p)], gave data in agreement with the experiments. Furthermore, the calculations predict for the first time a negative sign of 1J(13C,11B) which mirrors the bonding situation in 1 as described by theory.
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