Our Facebook account

E. D. Gerts¹, A. V. Komolkin¹, S. V. Dvinskikh^2,3

Author affiliations
¹Physical Faculty, St.-Petersburg State University,
Ul'yanovskaya str., 1, 198504 St.-Petersburg, Russia. 
E-mail: gerts-e-d@yandex.ru
²Laboratory of Biomolecular NMR, St.-Petersburg State University,
Botanicheskaya str., 17, 199034 St.-Petersburg, Russia
³Department of Chemistry, KTH Royal Institute of Technology,
SE-100 44, Stockholm, Sweden

Abstract
Conformational structure of the thermotropic nematic liquid crystal 4-(?-hydroxy-hexyloxy)-4’-cyanobiphenyl was investigated by NMR spectroscopy and molecular dynamics simulations. Experimental ¹³C NMR spectra in nematic and isotropic phases were obtained and analyzed. ¹³C NMR spectrum lines in mesophase were assigned to atoms in the molecule. Heteronuclear ¹³C – ¹H dipolar coupling constants were determined for every resolved carbon-13 line in the spectra. Molecular dynamics simulations of this substance in the nematic phase were carried out using standard inter- and intramolecular interaction potentials. Good correlation between simulated and experimental dipolar coupling constants was achieved. This suggests that the simulated system adequately corresponds to a structure of real liquid crystal. Thus the simulated conformational distribution of flexible 4-(?-hydroxy-hexyloxy) hydrocarbon chain gives the exact information on the conformations of the aliphatic chain in real liquid crystal.

Keywords: cyanobiphenyl, 2D NMR spectroscopy, molecular dynamics