Mirror inversion of the low-symmetry ground-state structures of the methylcyclohexane and 1,1-dimethylcyclohexane radical cations. An electron paramagnetic resonance study

The dynamics of the methylcyclohexane and 1,1-dimethylcyclohexane radical cations in a solid perfluoromethylcyclohexane matrix at low temperature have been studied by electron paramagnetic resonance (EPR) spectroscopy. The reversible variations of the experimental EPR linewidth, observed for both cations in the temperature region 4–173 K, have been reproduced through simulations employing a dynamical model for the molecular motion. It was assumed that an interconversion between two energetically equivalent mirror images of the molecular framework occurred. The related activation energy has been determined to be 0.2 and 0.3 kcal mol–1 for the methylcyclohexane and 1,1-dimethycyclohexane radical cations, respectively.