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Experimental and quantum chemical investigation of the stereochemical dependence of spin coupling constants in symmetrical strained alkenes †
Author(s) -
Berger Stefan,
Krebs Adolf,
Thölke Bernd,
Siehl HansUllrich
Publication year - 2000
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 - 10.1002/1097-458x(200007)38:7<566::aid-mrc674>3.0.co;2-h
Subject(s) - chemistry , coupling constant , spin (aerodynamics) , ab initio , computational chemistry , coupling (piping) , carbon 13 nmr , chemical shift , quantum chemical , fermi contact interaction , ab initio quantum chemistry methods , distortion (music) , molecular physics , atomic physics , molecule , stereochemistry , thermodynamics , quantum mechanics , organic chemistry , physics , mechanical engineering , engineering , amplifier , optoelectronics , hyperfine structure , cmos
The 13 C– 13 C, 13 C– 1 H and 1 H– 1 H spin coupling constants in some strained symmetrical alkenes were measured using a new gradient selected method. The olefinic 1 J (C,C) spin coupling constants were calculated using ab initio and DFT quantum chemical calculations for model compounds. The calculated and experimental data are in good agreement. The olefinic 1 J (C,C) spin coupling constants do not reflect the high distortion of the double bond in silacycloheptene 2 . This is attributed to the fact that the Fermi contact contribution to the coupling constants is transmitted via the sp 2 ‐type σ‐orbital, whereas the π‐type MO with a nodal plane at the position of the nuclei does not contribute to the 13 C– 13 C coupling. Copyright © 2000 John Wiley & Sons, Ltd.