Olga V. Dorofeeva, V. S. Mastryukov, A. Almenningen
1991
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0
Influential Citations
13
Citations
Journal
Journal of Molecular Structure
Abstract
Abstract The molecular structure of bicyclohexyl, (C6H11)2, has been studied by gas-phase electron diffraction with the aid of vibrational spectroscopy and molecular mechanics calculations (MM3 force field). According to these calculations, the most stable conformer is ee anti (C2h symmetry), whereas the next stable conformer, ee gauche, has C2 symmetry and differs by only 0.96 kJ mol−1 in energy. The third conformer, ea anti, has Cs symmetry and its energy content is 7.36 kJ mol−1. Infrared spectra have been recorded in the vapour phase and in argon and nitrogen matrices. From variable temperature measurements by Raman spectroscopy, the enthalpy difference ΔH√O (ee gauche—ee anti) was found equal to 1.5 ±1 kJ mol−1. The electron diffraction results have been interpreted in terms of a mixture of C2h and C2 con- formers only, with a ratio of 52.6 ±9.0% and 47.4 9.0%, respectively, at 112°C. The average main structural parameters of these conformers are as follows (ra structure): CCring1.535 (2) A, CCpivot1.550 (14) A, CH 1.102 (3) A; bond angles CCC 110.7 (10)o,CCH 109.1 (6)o the torsional angle, τ, in the gauche conformer is 74.90° The estimated standard deviations, while allowing for the effects of correlations (3σ), have been increased for internuclear distances to take account of systematic errors in the electron wavelength.