Cholesterol based mesogenic Schiff’s base derivatives with carbonate linkage: Synthesis, characterisation and photoluminescence study

Abstract

ABSTRACT The steroidal derivatives have been found to be extremely good mesogens since their origin. Due to their inherent chirality, they have the potential to induce a wide variety of liquid crystalline phases, including frustrated phases, depending on the structure of the steroidal skeleton and the substituents attached. In this report, thirteen new homologous Schiff’s base derivatives were synthesised by condensing 4-n-alkoxy aniline with 4-formyl phenyl cholesteryl carbonate. All the compounds were characterised using elemental analysis, FT-IR, 1H-NMR and 13C-NMR. In order to study the liquid crystalline behaviour of the synthesised compounds, optical texture studies were carried out using polarising optical microscope in heating and cooling cycles. The derivatives showed a variety of mesophases, including chiral nematic (N*), twist grain boundary-A (TGBA), smectic A (SmA) and chiral smectic C (SmC*) phases. The thermal behaviour was determined using a differential scanning calorimeter and thermogravimetric analysis. All the synthesised compounds are UV-active and show photoluminescence in the blue emission region with good quantum yield.