Synthesis and Characterization of Liquid Crystalline Materials Incorporating the Novel 4-Amino-1,2,4-triazole and Isonicotinic Acid Hydrazide Moiety

Abstract

We report the synthesis and evaluation of thermal behavior of two new mesogenic homologous series of liquid crystalline compound containg 1,2,4-triazole and isonicotinic acid ring at the terminus of the molecule viz. 4-[(4H-1,2,4-triazol-4-ylimino) methyl] phenyl 4-alkoxybenzoate and 4-(2-isonicotinoylcarbonohydrazonoyl) phenyl 4-alkoxybenzoate. Both series have been characterized by elemental analysis, FT-IR, mass spectrometry, ¹H-NMR, and ¹³C-NMR. Phase transition temperatures and the thermal parameters were obtained from differential scanning calorimetry (DSC). The texture observation was performed under polarizing optical microscopy (PMO) attached with Mettler hot stage. All the derivatives are mesomorphic in nature showing nematic phase and the higher member of both series shows smectic phase. The use of isonicotinic acid and triazole as a terminal group has a very dramatic effect on the melting and clearing points. The mesomorphic behavior has been analyzed in terms of structural property relationship.

Keywords:

• ester
• isonicotinic acid hydrazide
• mesophase
• nematic phase
• smectic phase
• schiff base
• triazole

ACKNOWLEDGMENT

We are thankful to I.I.T. Bombay, CDRI Lucknow, and Garda Chemicals Ltd., Ankleshwar (Gujarat) for providing an elemental analysis, FT-IR, ¹H-NMR, ¹³C NMR mass and thermal studies.

Notes

Note: SmC - Smectic C; N - nematic; I - isotropic.

Note: SmC - Smectic; N - nematic; I - isotropic.

Note: SmC - Smectic C; N - nematic; I - isotropic.

Note: Values in parantheses indicate monotropy.