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Synthesis of Mixed Tail Triphenylene Discotic Liquid Crystals: Molecular Symmetry and Oxygen-Atom Effect on the Stabilization of Columnar Mesophases
引用本文:赵可清,胡平,汪必琴,余文浩,陈红梅,王新玲,清水洋.Synthesis of Mixed Tail Triphenylene Discotic Liquid Crystals: Molecular Symmetry and Oxygen-Atom Effect on the Stabilization of Columnar Mesophases[J].中国化学,2007,25(3):375-381.
作者姓名:赵可清  胡平  汪必琴  余文浩  陈红梅  王新玲  清水洋
作者单位:[1]College of Chemistry and Material Sciences, Sichuan Normal University, Chengdu, Sichuan 610066, China [2]National Institute of Advanced Industrial Science and Technology (AIST), Kansai Centre, 1-8-31 Midorigaoka, Ikeda, Osaka 563-8577, Japan
基金项目:Project supported by the National Natural Science Foundation of China (Nos. 50473062, 50673069), the Sichuan Province Youth Foundation (No. 04-ZQ026-044) and the Research Project of Sichuan Province (No. 05GG009-005), China.
摘    要:Small change in chemical structure of discotic liquid crystals can cause big difference in their mesomorphism. Replacing of the alkoxy peripheral chains of triphenylene by oxygen-atom containing ester chains would result in novel mesomorphism. A series of mixed tail triphenylenes containing propoxyacetyloxy and alkoxy, abbreviated as C18H6(OCnH2n+1)3(OCOCH2OC3H7)3, n=4-8, and hexa(propyloxyacetyloxy)triphenylene, C18H6(OCOCH2OC3H7)6 were synthesized. Thermal gravimetry analysis (TGA) of three discogens showed that they had good thermal stability till 350 ℃. The mesomorphism was investigated through differential scanning calorimetry (DSC) and polarized optical microscopy (POM). The preliminary X-ray diffraction (XRD) results of one compound showed that it exhibited ordered hexagonal columnar (Colho) mesophase. These mixed tail triphenylene derivatives possessed much stable Colho mesophase and wider mesophase ranges than their hexaalkoxytriphenylene C18H6(OR)6 and hexaalkanoyloxytriphenylene C18H6(OCOR')6 analogues. The asymmetrical compounds 2,6,11-trialkoxy-3,7,10-tri(2-propyloxyacetyloxy)triphenylenes with n=5-8 displayed higher clearing points and wider temperature ranges than their symmetrical isomers 2,6,10-trialkoxy-3,7,11-tri(2-propyloxyacetyloxy)- triphenylenes, while C18H6(OCOCH2OC3H7)6 had the highest clearing point due to the β-oxygen-atom effect.

关 键 词:苯并菲  混晶须盘状液晶  合成  分子对称性  氧原子效应  柱状相稳定
修稿时间:2006-05-092006-11-15

Synthesis of Mixed Tail Triphenylene Discotic Liquid Crystals: Molecular Symmetry and Oxygen-Atom Effect on the Stabilization of Columnar Mesophases
ZHAO Ke-Qing, HU Ping, WANG Bi-Qin, YU Wen-Hao, CHEN Hong-Mei, WANG Xin-Ling, SHIMIZU Yo , Kansai Centre -- Midorigaoka, Ikeda, Osaka -, Japan.Synthesis of Mixed Tail Triphenylene Discotic Liquid Crystals: Molecular Symmetry and Oxygen-Atom Effect on the Stabilization of Columnar Mesophases[J].Chinese Journal of Chemistry,2007,25(3):375-381.
Authors:ZHAO Ke-Qing  HU Ping  WANG Bi-Qin  YU Wen-Hao  CHEN Hong-Mei  WANG Xin-Ling  SHIMIZU Yo  Kansai Centre -- Midorigaoka  Ikeda  Osaka -  Japan
Institution:a College of Chemistry and Material Sciences, Sichuan Normal University, Chengdu, Sichuan 610066, China ;b National Institute of Advanced Industrial Science and Technology (AIST
Abstract:Small change in chemical structure of discotic liquid crystals can cause big difference in their mesomorphism. Replacing of the alkoxy peripheral chains of triphenylene by oxygen‐atom containing ester chains would result in novel mesomorphism. A series of mixed tail triphenylenes containing propoxyacetyloxy and alkoxy, abbreviated as C18H6(OCnH2n+1)3(OCOCH2OC3H7)3, n=4–8, and hexa(propyloxyacetyloxy)triphenylene, C18H6(OCOCH2‐OC3H7)6 were synthesized. Thermal gravimetry analysis (TGA) of three discogens showed that they had good thermal stability till 350 °C. The mesomorphism was investigated through differential scanning calorimetry (DSC) and polarized optical microscopy (POM). The preliminary X‐ray diffraction (XRD) results of one compound showed that it exhibited ordered hexagonal columnar (Colho) mesophase. These mixed tail triphenylene derivatives possessed much stable Colho mesophase and wider mesophase ranges than their hexaalkoxytriphenylene C18H6(OR)6 and hexaalkanoyloxytriphenylene C18H6(OCOR′)6 analogues. The asymmetrical compounds 2,6,11‐trialkoxy‐3,7,10‐tri(2‐propyloxyacetyloxy)triphenylenes with n=5–8 displayed higher clearing points and wider temperature ranges than their symmetrical isomers 2,6,10‐trialkoxy‐3,7,11‐tri(2‐propyloxyacetyloxy)‐ triphenylenes, while C18H6(OCOCH2OC3H7)6 had the highest clearing point due to the β‐oxygen‐atom effect.
Keywords:triphenylene  discotic liquid crystal  columnar phase  β-oxygen-atom effect  molecular symmetry
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