Coumarin dimers of benzidine and phenylenediamine cores: synthesis, characterisation and mesomorphic properties

Three new homologous series of coumarin heterocycles-derived mesogens have been synthesised and characterised. The symmetric dimers of coumarin contain two Schiff base moieties as connecting groups with phenyl or biphenyl central cores. Chemical structures were evaluated using IR, NMR and CHN analysis techniques. Thermal, mesophase behaviours and textural types were studied by DSC and POM instrumentations. The nematic mesophase was enhanced prominently for most of the compounds, and which is appeared in relatively medium to long alkyl chain at both terminals of the molecules.