Liquid crystalline compounds containing lateral thiol group: synthesis, characterisation, its mesomorphic properties and DFT studies

One new homologous series of mesogenic compounds containing imine (-CH = N-) and ester (-COO-) linkages as well as lateral thiol (-SH) group and terminal alkoxy chain was synthezised. Molecules in the present work was convinced with respective right structure confirmed with FT-IR, H-1-NMR and C-13-NMR spectroscopy. Thermotropic properties of the compounds were investigated on a hot-stage plate of a polarising optical microscope and further by differential scanning calorimetry. All the compounds of the series exhibited excellent liquid crystalline nature. Structure-property relationships, the influence of different flexible spacers and the mesophase ranges were studied. Computational studies and the electron density method was performed with B3LYP method for all molecular structures in present work. The mesophase ranges were found to be dependent on the length and flexibility of the alkoxy chain, as well as the presence of the lateral thiol group. The comparative study of the present series with the geometrically related series provided valuable insights into the effect of molecular shape on the mesomorphic properties.