Maximum entropy internal order approach to the study of intramolecular rotations in liquid crystals

In this paper a systematic way of obtaining conformational information from the proton dipolar couplings of an internal rotor solute dissolved in a nematic liquid crystal is discussed. An algorithm is proposed that is suitable for automatic conversion of the experimental dipolar couplings into roto-conformational distributions by generalizing the previously proposed maximum-entropy approach. An error analysis on the distributions obtained is also performed for the first time. This maximum entropy internal order (MEIO) method has been applied to a re-analysis of proton NMR data of 3,3′,5,5′-tetrachlorobiphenyl and 2,2′-bifuryl in nematic liquid crystals and orientational order parameters and conformational distributions in the nematic phase have been obtained and compared with the single and cis–trans conformation approach.