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    Please use this identifier to cite or link to this item: http://tkuir.lib.tku.edu.tw:8080/dspace/handle/987654321/80009


    Title: Induction of the Columnar Phase of Unconventional Dendrimers by Breaking the C2 Symmetry of Molecules
    Authors: Lai, Long-Li;Wang, Sheng-Wei;Cheng, Kung-Lung;Lee, Jey-Jau;Wang, Tsai-Hui;Hsu, Hsiu-Fu
    Contributors: 淡江大學化學學系
    Keywords: dendrimers;liquid crystals;nitrogen heterocycles;symmetry breaking
    Date: 2012-11-26
    Issue Date: 2013-01-16 15:35:20 (UTC+8)
    Publisher: Weinheim: Wiley - V C H Verlag GmbH & Co. KGaA
    Abstract: Two triazine-based unconventional dendrimers were prepared and characterized by 1H and 13C NMR spectroscopy, mass spectrometry, and elemental analysis. Differential scanning calorimetry, polarizing microscopy, and powder XRD studies showed that these dendrimers display columnar liquid-crystalline phases during thermal treatment. This is ascribable to breaking of their C2 symmetry. The molecular conformations of prepared dendrimers were obtained by computer simulation with the MM3 model of the CaChe program in the gas phase. The simulation showed that the conformations of the prepared dendrimers are rather flat and disfavor formation of the LC phase. However, due to C2-symmetry breaking, the prepared dendrimers have structural isomers in the solid state and thus show the desired columnar phases. This new strategy should be applicable to other types of unconventional dendrimers with rigid frameworks.
    Relation: Chemistry - A European Journal 18(48), pp.15361-15367
    DOI: 10.1002/chem.201200933
    Appears in Collections:[化學學系暨研究所] 期刊論文

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