New azo-benzothiazole based liquid crystals: synthesis and study of the effect of lateral left-to-right marksubstituents on their liquid crystalline behaviour

New azo-phenylbenzothiazole moiety-based liquid crystals with diverse substituents/groups (H, OH, CH3, Cl, F) at position-3 of the central benzene ring were prepared and characterised. All synthesised compounds were characterised using H-NMR and FT-IR spectroscopy, mass spectrometry and elemental analysis. Thermal properties of mesophase of these liquid crystal compounds were studied to reveal that they all exhibited an enantiotropic nematic phase except for the compound bearing an OH group, i.e. EB1-OH. Two new azo-benzothiazole analogous, where the azo group is directly attached to the thiazole ring, were synthesised. The mesomorphic properties of the azo-phenylbenzothiazole liquid crystalline compounds were compared with these compounds to evaluate the effect of the nature of the lateral substituents on their mesomorphic properties.