2H NMR and X-ray studies of a substance exhibiting crystal-like smectic phases

DSC, polarizing optical microscopy and X-ray diffractometry were used to investigate the mesomorphic behavior of 4-n-butyl-4'-acetyl-biphenyl, which resulted to exhibit a smectic E and, possibly, a smectic K phase. Addnl., 2H NMR spectroscopy was applied on a selectively deuterated sample to study the properties of alignment of the mesophases within a magnetic field, as well as to characterize mol. dynamics. Two motional processes were found to be active in the smectic E phase, namely fast Ĉ-flips of the benzene rings and mol. self-diffusion about the herringbone bidimensional lattice of the layers. No mol. overall diffusional motions were obsd. by either 2H NMR spectroscopy or dielec. relaxation measurements.