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Ionic Bent Shape Ternary Facial Amphiphiles

Chinese Journal of Chemistry 2013年第6期31卷 839-844页

作者： Chixian He Qingye He Sijing Zhang Xiaoping Tan Hongfei Gao Xiaohong Cheng School of Chemistry and Material Engineering Yunnan University Yunnan 650091 China

Novel bent shape tenary facial amphiphilic imidazolium ILC which consist of a ^-conjugated bent aromatic cores （2,5-dithiophenylethynyl phenyl bent core）, two terminal poliphilic alkyl chains and lateral n-alky chain terminated by an imidazolium bromide unit were synthesized by using Kumada and Sonogashira coupling reactions as key steps and both their thermotropic and lyotropic mesophase behaviors were studied by POM, DSC and XRD. columnar phases were found in these compounds, a hexagonal cylinder model with core shell structure is supposed for the columnar phase formed by compound 1/8. Our study may provide a new strategy for designing new LC functional material.

关键词： C--C-coupling reaction facial amphiphilic ionic liquid crystal bent shape columnar phase

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Synthesis of Mixed Tail Triphenylene Discotic Liquid Crystals： Molecular Symmetry and Oxygen-Atom Effect on the Stabilization of columnar Mesophases

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Chinese Journal of Chemistry 2007年第3期25卷 375-381页

作者：赵可清胡平汪必琴余文浩陈红梅王新玲清水洋 College of Chemistry and Material Sciences Sichuan Normal University Chengdu Sichuan 610066 China National Institute of Advanced Industrial Science and Technology (AIST) Kansai Centre 1-8-31 Midorigaoka Ikeda Osaka 563-8577 Japan

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： triphenylene discotic liquid crystal columnar phase β-oxygen-atom effect molecular symmetry

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phase STRUCTURES AND TRANSITION BEHAVIORS OF A TRIPHENYLENE DISCOTIC LIQUID CRYSTAL

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Chinese Journal of Polymer Science 2007年第1期25卷 57-71页

作者： Kwang-Un Jeong Alexander J.Jing Bart Mansdorf Matthew J.Graham Frank W.Harris 程正迪 Maurice Morton Institute and Department of Polymer Science The University of AkronAkronOhio 44325-3909USA

The phase behaviors and structures of a triphenylene-derived discotic liquid crystal （LC） hexa-n-octoxyl- triphenylene （C8HET） were studied using the combined techniques of differential scanning calorimetry （DSC）, wide angle X-ray diffraction （WAXD）, selected area electron diffraction （SAED） and polarized light microscopy （PLM）. Onedimensional （1D） powder WAXD results at different temperatures coupled with DSC and PLM observations revealed that the C8HET compound possessed an LC phase and three different crystalline （K3, K2 and K1） phases below the isotropic （I） melt. The I←→ LC phase transition was thermodynamically reversible and independent of the heating and cooling rates. The development and experimental observation of the three crystalline phases relied on different thermal histories. Among the three crystalline phases in CSHET, the K3 phase is the most stable phase, while the K2 and K1 phases are metastable. Note that the K1 phase only formed via a quenching process. Oh the basis of structure sensitive diffraction experiments such as 2D WAXD of oriented samples and SAED of single crystals, detailed structures and molecular packings of these four ordered phases were identified. The LC phase exhibited a hexagonal columnar phase with 2D lattice dimensions ofa = b = 2.38 nm and γ= 120°. All the three crystalline phases possess monoclinic unit cells, yet the y angle is not 90° in the cases of the K2 and the K3 phases, while in the case of the K1 phase the a angle is not 90°.

关键词： Triphenylene discotic liquid crystal Metastability Crystal structure columnar phase phase transitions.

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