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Indirect nuclear spin–spin coupling constants in 1,2‐diboretane‐3‐ylidene, a homoaromatic system with π and σ 3c/2e bonds. Comparison of experimental data with calculations using density functional theory (DFT)
Author(s) -
Wrackmeyer Bernd,
Berndt Armin
Publication year - 2004
Publication title -
magnetic resonance in chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0749-1581
DOI - 10.1002/mrc.1372
Subject(s) - chemistry , density functional theory , coupling constant , spin (aerodynamics) , computational chemistry , spin density , coupling (piping) , molecular physics , quantum mechanics , condensed matter physics , thermodynamics , physics , mechanical engineering , engineering
The non‐classical 1,2‐diboretane‐3‐ylidene 1a was studied by 13 C and 29 Si NMR spectroscopy in order to obtain coupling constants 1 J ( 13 C, 11 B) and 1 J ( 29 Si, 13 C). The magnitudes of 1 J ( 13 C, 11 B) were deduced from linewidth measurements in low‐temperature 13 C and 11 B 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 1 J ( 13 C, 11 B) which mirrors the bonding situation in 1 as described by theory. Copyright © 2004 John Wiley & Sons, Ltd.