Angle of twist between the two rings of 4-cyanobiphenyl when dissolved in liquid-crystalline solvents

Abstract

The structure of 4-cyanobiphenyl when dissolved in nematic liquid-crystalline solvents has been investigated. This has been achieved by recording and analysing the proton and deuterium NMR spectra of samples dissolved in the nematic solvents. The dipolar couplings obtained are compared with values calculated by averaging over the bond rotational motion, and the conclusion is reached that the minimum-energy structure has an angle between the two ring normals of 37.0 ± 0.1° in each of three solvents, compared with a value for biphenyl, obtained previously by the same method, of 37.4 ± 0.2°.