Guest dynamics in solid acetone-d₆-DOCA and acetone-d₆-APA inclusion compounds: Correlation between the symmetry of the motion and the site symmetry of the host lattice

The molecular motion of acetone-d₆ acting as guest in deoxycholic acid and apocholic acid host lattices in the solid state is interpreted in light of a broader concept assessing that very often the motion of the guest proceeds through discrete jumps rather than diffusively and its symmetry is cogenial with the site symmetry of the host lattice. In particular, the acetone molecules are engaged in threefold jumps about a unique axis, compatible with the 32 site symmetry of the host lattice. The entire dynamic range of this process is investigated in terms of spectral consequences brought about by variations in jump rates, in the relative population of the three symmetry related sites, and in instrumental parameters such as the time interval between the two 90° pulses in the quadrupole echo sequence and the length of the 90° pulses.