A carbon-13 cp/mas NMR investigation of the conformation of substituted cyclohexanes in thiourea inclusion compounds

✍ Scribed by Michael S. McKinnon; Roderick E. Wasylishen

• Publisher: Elsevier Science
• Year: 1986
• Tongue: English
• Weight: 330 KB
• Volume: 130
• Category: Article
• ISSN: 0009-2614
• DOI: 10.1016/0009-2614(86)80259-7

✦ Synopsis

Inclusion compounds of several monosubstituted cyclohexanes and thiourea have been studied using high-resolution "C CP/MAS NMR spectroscopy.

The "C NMR chemical shifts of the substituted cyclohexane ring are sensitive to the conformation of the substituent and allow one to predict qualitatively the relative populations of the axial and equatorial conformers. For methylcyclohexane trapped m thiourea the methyl substituent prefers the equatorial conformation while for the cyclohexyl halides (Cl, Br and I) the axal conformer is preferred. In the case of fluorocyclohexane the equatorial conformer appears to predominate; however, this conformer 1s in rapid equilibrium with the axial conformer.