Nematogenic homologous series of coumarin derivatives containing azomethine-ester linkages: synthesis, characterisation, photophysical and mesomorphic properties

Novel Homologous series of coumarin based Schiff's base derivatives derived from 4'-formyl phenyl 7-n-alkoxycoumarin-3-carboxylate and 4-n-(decyloxy)aniline have been synthesised. The proposed structures of all the newly prepared compounds were confirmed by FT-IR, H-1-NMR, C-13-NMR and elemental analysis. The photophysical properties of the coumarin based Schiff's base derivatives have been studied. The textures of coumarin based Schiff's base derivatives and their transition temperature were observed and recorded under a polarising optical microscope. The enthalpy change data were measured using Differential Scanning Calorimetry. By varying the alkoxy group (n = 1-10, 12, 14, 16) at the terminal position at one end of the moiety, the nematic phase was observed on heating as well as cooling. The thermal stability of all the compounds was recorded using thermal gravimetry analysis. [GRAPHICS]