Polar effect in columnar unsymmetric 1,3,4-oxa(thia)diazoles

Please use this identifier to cite or link to this item: https://ir.lib.ncu.edu.tw/handle/987654321/101248

Title:	Polar effect in columnar unsymmetric 1,3,4-oxa(thia)diazoles
Authors:	陳銘洲;Hu, Tarng-Shiang;Lin, Kuan-Ting;Mu, Chih-Chin;Kuo, Hsiu-Ming;Chen, Ming-Chou;Lai, Chung K.
Contributors:	理學院化學學系
Keywords:	1,3,4-Oxadiazoles;chemical reactions;chemical structure;Columnar phases;Derivatives;Diffractometers;emissions;Formations;Liquid crystals;nitrogen dioxide;organic compounds;Phases;Photoluminescence;Polar effect;Quinoxalines;Spectral emissivity;Tetrahedrons;X-ray diffraction
Date:	2014-08-28
Issue Date:	2026-04-21 14:28:23 (UTC+8)
Publisher:	Elsevier Ltd.;Elsevier Ltd
Abstract:	摘要： Three new series of heterocyclic 1,3,4-oxa(thia)diazoles 1a–c were prepared and their mesomorphic behavior studied. All compounds 1a exhibited monotropic columnar phases, which were confirmed by powder XRD diffractometer. Compounds 1b were not mesogenic. The formation of columnar phases was sensitive to the substituent groups attached on the phenyl moiety; those with electron-donating groups (R=H, OCH3) were not liquid crystals, in contrast, other derivatives with electron-withdrawing groups (R=F, NO2) formed enantiotropic columnar phases. A Ncell and Rar value equal to 4.73 and 20.20 Å2 of compound 1a (n=16) within a slice of 9.0 Å thick were obtained, indicating that two molecules was correlated to give a supplemental more disc-like molecule within columns. This is the first example, showing that the formation of columnar phases could be controlled by polar groups. The PL spectra of two compounds 1a–c showed one intense peak at λmax=505–511 nm, and these photoluminescent emissions originated from quinoxaline moiety. [Display omitted] 出版者： Elsevier Ltd 出版日期： 2014-12-02 出處： Tetrahedron, 2014-12, Vol.70 (48), p.9204-9213 版權： 2014 識別號： ISSN: 0040-4020 識別號： EISSN: 1464-5416 識別號： DOI: 10.1016/j.tet.2014.10.025
Appears in Collections:	[Department of Chemistry] journal & Dissertation

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