Coupling constants in fluorinated cyclic compounds. Part 3.—Coupling constants and chemical shifts of perfluoromethylcyclohexane

Abstract

The ¹⁹F nuclear magnetic resonance spectrum of perfluoromethylcyclohexane has been studied. The chemical shifts have been established with precision due to the use of an extended lock in the HA mode and some coupling constants between the ring-fluorine nuclei have been obtained. Variation of temperature and of solvent has been used to study the self-association in solution and a spectrum accummulator employed to record the spectrum of a possible second conformer. It is concluded that the molecule is probably fixed but may be slowly interconverting having an enthalpy difference between the two chair conformations of less than 0.5 kcal mole^–1.