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Dicyclohexylethyleneglycol, -diethyleneglycol, -triethyleneglycol, and related monosubstituted cyclohexanes. Conformational analysis using low-temperature 13 C and 1 H NMR spectroscopy

Two conformations of each of the title molecules have been detected by 100 MHz 13 C NMR at 210 K. For the dicyclohexyl systems, the conformations are related via a single ring inversion. In each case the equatorial–axial conformer is 4.7 ± 0.4 kJ/mol less stable than the diequatorially substituted f...

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Bibliographic Details
Published in:Canadian journal of chemistry 1995-04, Vol.73 (4), p.566-572
Main Authors: Buchanan, G.W., Moghimi, A., Reynolds, V.M., Bourque, K.
Format: Article
Language:English
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Summary:Two conformations of each of the title molecules have been detected by 100 MHz 13 C NMR at 210 K. For the dicyclohexyl systems, the conformations are related via a single ring inversion. In each case the equatorial–axial conformer is 4.7 ± 0.4 kJ/mol less stable than the diequatorially substituted form in CD 2 Cl 2 solution. For monosubstituted models, the conformational free energy (−ΔG 0 ) values of the -O-CH 2 -CH 2 -OCH 3 , -OCH 2 -CH 2 -O-CH 2 -CH 3 , and -O-CH 2 -CH 2 -O-CH-(CH 3 ) 2 groups have been determined to be 5.4,6.1, and 6.1 ± 0.2 kJ/mol, respectively. In methanol, the latter equilibria are slightly more biased towards the axially substituted conformers. Keywords: substituted ethylene glycols, conformational equilibria.
ISSN:0008-4042
1480-3291
DOI:10.1139/v95-073