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

Single-crystal X-ray diffraction and C-13 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-cryst al H-2 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 ov erlapping equivalent positions can account for the C-13 NMR spectrum at roo m temperature. The high crystallographic symmetry arises from space averagi ng. At high temperatures the C-13 spectrum is consistent with the onset of dynamic processes that result in higher effective symmetry.