Crystal structure and 13C CP/MAS NMR of the p-xylene clathrate of Dianin's compound

Single-crystal X-ray diffraction and ¹³C solid state NMR spectroscopy were used to characterize the structure and dynamics of the p-xylene clathrate of Dianin's compound. In contrast to conclusions obtained from single-crystal ²H NMR and modelling, the diffraction results suggest there is a single (symmetry disordered) guest site without any significant distortion of the host framework. A single xylene guest statistically disordered over six overlapping equivalent positions can account for the ¹³C NMR spectrum at room temperature. The high crystal-lographic symmetry arises from space averaging. At high temperatures the ¹³C spectrum is consistent with the onset of dynamic processes that result in higher effective symmetry.