Microwave-assisted synthesis, structure, and tunable liquid-crystal properties of 2, 5-diaryl-1, 3, 4-thiadiazole derivatives through peripheral n-alkoxy chains

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review

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Author(s)

  • Jie Han
  • Xiao-Yong Chang
  • Li-Rong Zhu
  • Mei-Li Pang
  • Ji-Ben Meng
  • Stephen Sin-Yin Chui
  • Siu-Wai Lai

Detail(s)

Original languageEnglish
Pages (from-to)1099-1107
Journal / PublicationChemistry - An Asian Journal
Volume4
Issue number7
Publication statusPublished - 6 Jul 2009

Abstract

A series of substituted 2, 5-diaryl-1, 3, 4-thiadiazole derivatives are prepared by microwave-assisted synthesis in the absence of an organic solvent. All derivatives are well characterized by 1H and 13C NMR, MS, and elemental analyses. The X-ray crystal structure of 2, 5-di-(4-decyloxyphenyl)-1, 3, 4-thiadiazole reveals the tilt lamellar arrangement of rod-shaped molecules, which are stabilized by a variety of weak non-covalent interactions. The liquid crystalline properties are studied by polarized-light optical microscopy (POM), differential scanning calorimetry (DSC), and in situ variable temperature X-ray diffraction (VTXRD). By variations in the peripheral n-alkoxy chains, the calamitic mesogens exhibit enantiotropic smectic (SmC and/or SmA) mesophases with wide mesomorphic temperature ranges, whilst the disc-like mesogens form hexagonal columnar mesophase (Col h) at room temperature. The bulk electrical conductivity values of the smectic mesophases of 1-3 are in the range of 10-3-10 -4 Scm-1, which are slightly higher than that of their solid films. In contrast, the solid film made from 2, 5-di-(3, 4, 5-tri-ACHTUNGTRENUNGoctyloxyphenyl)-1, 3, 4-thiadiazole shows poor conductivity (2×10-7 Scm-1). ©2009 Wiley-VCH Verlag GmbH&Co. KGaA, Weinheim.

Research Area(s)

  • Conducting materials, Diarylthiadiazole, Liquid crystals, Mesophases, Microwave chemistry

Citation Format(s)

Microwave-assisted synthesis, structure, and tunable liquid-crystal properties of 2, 5-diaryl-1, 3, 4-thiadiazole derivatives through peripheral n-alkoxy chains. / Han, Jie; Chang, Xiao-Yong; Zhu, Li-Rong; Pang, Mei-Li; Meng, Ji-Ben; Chui, Stephen Sin-Yin; Lai, Siu-Wai; Roy, V. A L.

In: Chemistry - An Asian Journal, Vol. 4, No. 7, 06.07.2009, p. 1099-1107.

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review