Phase transition and dynamic structure in the toluene clathrate of t-butylcalix[4]arene

Abstract
Variable temperature solid-state 13C NMR and differential scanning calorimetry were used to show that the toluene clathrate of t-butylcalix[4]arene undergoes a symmetry lowering phase transition at 248.0 K. 2H NMR was used to show that the high symmetry of the complex at room temperature is due to dynamic disorder of the toluene guest, which is most easily described as an axial rotor.