Guest Loading and Multiple Phases in Single Crystals of the van der Waals Host p-tert-Butylcalix[4]arene

We have followed the loading of xenon into the low density form of a van der Waals solid host, p-tert-butylcalix[4]arene (tBC), with solid-state NMR and X-ray diffraction (XRD), techniques sensitive to local and long-range order, respectively. Even though there was little change in the unit cell parameters, 13C and 129Xe solid-state NMR spectra indicate that significant structural changes occur in local order even at low levels of loading. In …