Abstract
Six members of homologues series of the liquid crystal dimers, 4-n-alkoxybenzylidine-4′-bromoaniline disulphides, which contain a sulphur–sulphur (S–S) link in the flexible spacer have been synthesised and their liquid crystalline properties were characterised. The dimers possess a general formulation in which a S–S group situated between two identical bromo-substituted aromatic imines have bonded, respectively, to S atom through the methylene unit of –(CH2)n– in which n denotes the number of carbon atoms. The number of carbon atoms in the spacers were varied following ascending order from 3 to 8. The dimers with a shorter spacer (n = 3 and 4) displayed nematic phase as well as smectic phase. The higher homologues in which n = 5–8 exhibited smectogens. The odd–even effect can be ascribed to the torsion angle of S–S linkage.
Acknowledgements
The author (G.Y. Yeap) would like to thank Universiti Sains Malaysia for providing the research facilities.