Molecular motion in solid diamantane studied by nuclear magnetic resonance

Abstract

N.m.r. measurements of proton relaxation times and second moments for solid diamantane have been made from 100 K to its melting point at 518 K. The upper temperature phase, from 442.5 to 518 K, was found to be a plastic phase exhibiting rapid molecular reorientational motion and translational motion with an activation enthalpy of 99.7 ± 1.6 kJ mol^–1. The lower temperature phases are non-plastic and the molecules undergo anisotropic reorientational motion. The measured values of the activation enthalpies are compared with previously predicted theoretical values.