Columnar liquid crystalline benzenetrisamides with pendant 1,3,4-oxadiazole groups |
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| Authors: | Joaquín Barberá Mariel A Godoy Paulina I Hidalgo José A Ulloa Jorge M Vergara |
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| Institution: | 1. Facultad de Ciencias–Instituto de Ciencia de Materiales de Aragón, Química Orgánica , Universidad de Zaragoza–CSIC, 50009 , Zaragoza, Spain;2. Facultad de Ciencias Químicas, Departamento de Química Orgánica , Universidad de Concepción , Concepción, Chile |
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| Abstract: | Novel liquid crystal materials based on 1,3,5-benzenetrisamide derivatives with three pendant 2-phenyl-5-(mono-, di-, and/or tri-n-alkoxyphenyl)-1,3,4-oxadiazole arms (Ia–c, IIa–c) were prepared. The mesomorphic properties of these compounds were characterised and studied by differential scanning calorimetry, polarising optical microscopy and X-ray diffraction. The formation of a columnar mesophase was found to be dependent on the number of alkoxy side chains. The compounds Ib and IIb, with a total of six alkoxy chains, and compounds Ic and IIc, with nine alkoxy chains, exhibited an enantiotropic hexagonal columnar (Colh ) phase with high isotropisation temperatures; however, compounds Ia and IIa with a total of three alkoxy chains formed a crystalline phase. Compounds IIb and c were room temperature liquid crystals. |
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| Keywords: | liquid crystals 1 3 4-oxadiazoles benzenetrisamides mesophases hexagonal columnar phase |
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