Synthesis, Characterization and Mesomorphic Properties of New Rod-like Thiophene Based Liquid Crystals

Abstract

Two new mesogenic homologous series of Schiff base esters, 2-[4-(4′-n-Alkoxy benzoyloxy) benzylidenamino] 3-cyno thiophine (Series-A) and Schiff base cinnamates, 2-[4-(4′-n-alkoxy cinnamoyloxy) benzylidenamino] 3-cyano thiophene (Series-B), comprising a thiophene moiety were synthesized. Structural elucidation was carried out using elemental analysis and spectroscopic techniques such as FT-IR, ¹H-NMR and ¹³C-NMR, and mass spectrometry. The mesomorphic properties and thermal stabilities of the title compounds were studied by using differential scanning calorimetry and optical polarizing microscopy. All the derivatives are mesomorphic in nature showing the nematic phase, and the higher members of Series-A show a smectic C phase whereas Series-B exhibits only the nematic mesophase. The mesomorphic properties of the present series are compared with other structurally related compounds.

Keywords:

• 3-cyno thiophene
• cinnamates
• ester
• nematic
• schiff base
• smectic C

Acknowledgment

The authors are thankful to Gujarat Narmada Valley Fertilizer Company Ltd. (G.N.F.C.), Bharuch, for providing facilities of elemental analysis, to Atul Industries Ltd. Atul, for DSC analysis, and also to SAIF Chandigarh for providing facilities of FT-IR, ¹H-NMR,¹³C-NMR, and Mass spectral analysis.