Premium
Substituent effects on inversion motion of 4‐silatriafulvene derivatives: An ab initio MO study
Author(s) -
Takahashi Masae,
Sakamoto Kenkichi,
Kira Mitsuo
Publication year - 2001
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.1322
Subject(s) - bent molecular geometry , chemistry , ab initio , substituent , planar , computational chemistry , inversion (geology) , ab initio quantum chemistry methods , silicon , bond length , ring flip , silylation , molecular geometry , spectral line , crystallography , molecule , molecular physics , stereochemistry , crystal structure , organic chemistry , physics , quantum mechanics , ring (chemistry) , paleontology , computer graphics (images) , structural basin , computer science , biology , catalysis
The structure and spectroscopic characteristics of various 4‐silamethylenecyclopropene (4‐silatriafulvene) derivatives were investigated using ab initio MO calculations. The minimum energy geometries of all of the derivatives studied here were trans ‐bent around the SiC double bond, and the planar structures were found to be the transition states for the inversion motion between the two equivalent bent structures. The barriers were very low to allow facile inversion at room temperature. It was found that silyl substitution at the unsaturated silicon lowered the barrier height of the inversion motion. Significant differences were found in the calculated absorption maxima and 29 Si NMR chemical shifts between the planar and trans ‐bent 4‐silatriafulvene derivatives, which suggested significant temperature dependence in the spectra. All of these features were in good agreement with the experimental results for a 4‐silatriafulvene derivative, 1,2‐di‐ tert ‐butyl‐4,4‐bis( tert ‐butyldimethylsilyl)‐4‐silamethylenecyclopropene, that we recently isolated. © 2001 John Wiley & Sons, Inc. Int J Quantum Chem 84: 198–207, 2001