Synthesis of Triphenylene Discotic Liquid Crystals Possessing Nine Alkyl Chains: Influence of Molecular Symmetry and Chain Length on Mesomorphism
Synthesis of Triphenylene Discotic Liquid Crystals Possessing Nine Alkyl Chains: Influence of Molecular Symmetry and Chain Length on Mesomorphism
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DOI：
10.1080/15421406.2013.781489
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发表时间：
2013-07
影响因子：
0.7
通讯作者：
B. Xiao;Zhaoqing Liu;Bi-qin Wang;P. Hu;C. Redshaw;K. Zhao
中科院分区：
文献类型：
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作者：
B. Xiao;Zhaoqing Liu;Bi-qin Wang;P. Hu;C. Redshaw;K. Zhao
用直接法合成了一系列新型的苯并菲双嵌段液晶，并研究了分子对称性和链长对液晶性的影响。利用偏光显微镜（POM）、差示扫描量热法（DSC）和广角X射线衍射（XRD）对对称化合物1，3，7，11-三甲氧基苯并菲-2，6，10-三基三（3，4，5-三烷氧基苯甲酸酯）（C7，C8，C10，C12）和不对称化合物2进行了研究。结果表明，在较宽的温度范围内，对称化合物1a（C7）和1b（C8）呈现塑性柱状中间相，而其它化合物呈现六方柱状中间相。所有对称化合物1的各向同性温度均高于不对称化合物2。清亮点随着烷基链的延长而降低。
A series of new triphenylene discotic liquid crystals has been synthesized by a straightway and the influence of molecular symmetry and chain length on the mesomorphism investigated. The symmetrical compounds 1, 3,7,11-trimethoxytriphenylene-2,6,10-triyl tris(3,4,5-tris(alkyloxy)benzoate), with alkyl chain lengths of C7, C8, C10, and C12, and the unsymmetrical compounds 2 were studied by using polarized optical microscopy (POM), differential scanning calorimetry (DSC) and by wide-angle X-ray diffraction (XRD). The results showed that the symmetrical compounds 1a (C7) and 1b (C8) exhibit a plastic columnar mesophase, whereas the other compounds display a hexagonal columnar mesophase over a wide temperature range. All symmetrical compounds 1 display higher isotropization temperatures than that of the unsymmetrical 2. The clearing points are lowered as the alkyl chain lengthened.