Study of the Ferroelectric Liquid Crystal 11EB1M7 by Means of 2H NMR

In this work, a new procedure for the synthesis of the selectively deuterium-labeled chiral liquid crystal (+)-(S)-4-[4‘-(1-methylheptyloxy)] biphenyl 4-(10-undecenyloxy)benzoate (11EB1M7) has been developed, aimed to the study of its structure, orientational ordering, and dynamic behavior by means of 2H NMR. 11EB1M7 was investigated throughout its mesophasic range, formed by a very rich variety of chiral liquid crystalline phases including blue, cholesteric, TGBA*, and smectic C*. Two isotopomers were synthesized by labeling 11EB1M7 on either the phenyl or the biphenyl moiety of the mesogenic core. This allowed structural information (such as the tilt angle of the rigid fragments of the molecule and the angle between their para axes), orientational order parameters, and individual diffusional coefficients for the various overall and internal motions to be obtained from 2H NMR spectra and relaxation measurements by applying suitable data analyses based on several theoretical models.