in Journal of Physical Chemistry A, 116, American Chemical Society, December 2012.
We investigate the relationship between intramolecular rotational dynamics and molecular and crystal structure in 4,4′-dimethoxyoctafluorobiphenyl. The techniques are electronic structure calculations, X-ray diffractometry, and 1H and 19F solid state nuclear magnetic resonance relaxation. We compute and measure barriers for coupled methyl group rotation and methoxy group libration. We compare the structure and the structure-motion relationship in 4,4′-dimethoxyoctafluorobiphenyl with the structure and the structure-motion relationship in related compounds in order to observe trends concerning the competition between intramolecular and intermolecular interactions. The 1H spin-lattice relaxation is nonexponential in both the high-temperature short-correlation time limit and in the low-temperature long-correlation time limit, albeit for different reasons. The 19F spin-lattice relaxation is nonexponential at low temperatures and it is exponential at high temperatures.