Liquid crystals with a 5-phenyltropone core

Abstract

Liquid crystals with a 5-phenyltropone structure were prepared. 5-(4-Alkanoylaminophenyl)tropone derivatives (5 and 6) showed smectic A and C phases. From the layer spacing, compound 5q formed an interdigitated bilayer smectic A phase. The variable temperature FTIR spectra of 5q indicated the presence of intermolecular hydrogen bonding between the amide carbonyl group and the NH group on the phenyl ring of neighbouring molecules. The amide groups of the 2-alkanoylamino-5-phenyltropones controlled the occurrence of mesophases through not only inter- and intra-molecular hydrogen bonds, but also dipole-dipole interaction with the tropone carbonyl group of neighbouring molecules.