Indirect nuclear spin-spin coupling constants in 1,2-diboretane-3-ylidene, a homoaromatic system with pi and sigma 3c/2e bonds. Comparison of experimental data with calculations using density functional theory (DFT).
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.
Wrackmeyer
Bernd
B
Anorganische Chemie II, Universität Bayreuth, D-95440 Bayreuth, Germany. b.wrack@uni-bayreuth.de
Berndt
Armin
A
D000465:Algorithms; D001896:Boron Compounds / Q000032:analysis* / Q000737:chemistry*; D003198:Computer Simulation; D006841:Hydrocarbons, Aromatic / Q000032:analysis* / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008956:Models, Chemical; D008958:Models, Molecular; D008968:Molecular Conformation; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013113:Spin Labels
D001896:Boron Compounds; D006841:Hydrocarbons, Aromatic; D013113:Spin Labels