Azomesogens: (I) 4-(4′ −n-Alkoxy-2′ −Methylphenylazo)—Benzoic acids: (II) Ethyl 4-(4′ −n-Alkoxyphenylazo)—Benzoates

Abstract

Abstract Two mesongenic homologous series containing azo group are synthesized. The esters of Series II, III and IV exhibit only the smectic phase. The smectic phase exhibits focal conic or fan-shaped textures. Members of Series I exhibit nematic phases, whereas the members of Series II and IV exhibit enantiotropic smectic phase with one exception. The members of series IV exhibit odd-even effects for smectic-isotropic transition temperatures. The smectic phase appears ∼70° to 90° C. The thermal stabilities and structural aspects are discussed in detail. All the compounds were characterised by standard methods. The visible spectra helped to obtain λmax of the mesogens.