Conformational free energy difference (–ΔG° value) of the methyl group in methylcyclohexane: an accurate determination by the direct, low-temperature nuclear magnetic resonance method
1976; Royal Society of Chemistry; Issue: 8 Linguagem: Inglês
10.1039/c39760000278
ISSN2050-5639
AutoresHarold Simmons Booth, Jeremy R. Everett,
Tópico(s)Analytical Chemistry and Chromatography
ResumoThe low-temperature pulse Fourier transform 13C n.m.r. spectrum of methylcyclohexane, enriched with 13C in the methyl substituent, shows that the ratio of major conformation (methyl equatorial) to minor conformation (methyl axial) is 164 : 1 (0·6% methyl axial), corresponding to a conformational free energy difference at 172 K of 1·74 ± 0·06 kcal mol–1(7·30 ± 0·25 kJ mol–1).
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