The determination of the conformation of the aromatic rings in a lateral fluoro-substituted liquid crystal by 13C NMR spectroscopy

Abstract

A ¹³C–{¹H} NMR spectrum of 2,2′-difluoro-4″-hexoxy-4-pentyl-[1,1′ ∶ 4′,1″]-terphenyl in the nematic phase has been obtained and analysed to yield a set of partially-averaged dipolar couplings, D^CF_ij, which are used to determine the relative conformation of the two fluorinated rings. The probability distribution for the inter-ring angle is found to be peaked at 47.5 ± 2.5° and 122.5 ± 2.5°. The integrated, normalised probability that the inter-ring angle is less than 90° is 0.43.