Liquid Crystalline Properties of 2,5-Bis[4-n-alkoxybenzoyloxy-(4-benzoyloxy)]-3,6-dichloro-1,4-benzoquinones: Synthesis and Characterization

摘要

A new series of 2,5-bis[4-n-alkoxybenzoyloxy-(4-benzoyloxy)]-3,6-dichloro-1,4-benzoquinones, C₆Cl₂O₂(OCOC₆H₄OCOC₆H₄OR)₂, where R = C_mH_{2m + 1} and m = 7, 8, 9, 10, 11, 12, 14, and 16, have been synthesized. These compounds have been characterized by elemental analyses, FT-IR, UV-visible, 1H, and 13C NMR spectra. Mesomorphic properties of these compounds were studied by differential scanning calorimetry (DSC) and polarizing optical microscopy (POM). The mesomorphic nature of these compounds depends on the alkoxy chain length. The compounds (m = 7, 8, 9, 10) exhibit a monotropic nematic mesophase in cooling cycle, while the compounds (m = 11, 12, 14, and 16) show no mesogenic behavior in both heating and cooling cycles. The intermolecular interactions play a vital role in the mesogenic nature of these compounds. In higher homologues of the series the intermolecular interactions become more prominent leading to loss in mesogenic nature.