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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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Published in: | Canadian journal of chemistry 1995-04, Vol.73 (4), p.566-572 |
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Main Authors: | , , , |
Format: | Article |
Language: | English |
Citations: | Items that this one cites Items that cite this one |
Online Access: | Get full text |
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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. |
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ISSN: | 0008-4042 1480-3291 |
DOI: | 10.1139/v95-073 |