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Synthesis of unsymmetric triphenylene discotic liquid crystals with a semi-fluorinated chain and the influence of fluorophobic effect on mesogenic behavior

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Science China Chemistry 2009年第8期52卷 1244-1252页

作者： YANG GaoFan ZHAO KeQing YU WenHao HU Ping WANG BiQin College of Chemistry and Materials Science Sichuan Normal UniversityChengdu 610066China

The fluorophobic effect of the semi-fluorinated chain of discotic molecules efficiently improves the stability of columnar *** symmetric discogens exhibit decreased melting points and wide mesophase ranges.A series of triphenylene derivatives 1,C18H6(OCnH2n+1)4(OMe)(O2CC2H4C6F13),and their hydrocarbon analogues 2,C18H6(OCnH2n+1)4(OMe)(O2CC8H17),n = 4―8,were synthesized for the investigation of the influence of semi-fluorinated peripheral chain and molecular symmetry on *** structures were characterized with 1H NMR and *** mesomorphism was studied with differential scanning calorimetry(DSC) and polarizing optical microscopy(POM).The results showed that all triphenylene derivatives exhibited enantiotropic columnar *** semifluorinated triphenylenes 1a―1e displayed higher melting points and clearing points than their hydrocarbon analogies 2a―*** of them were in columnar mesophase at room temperature.

关键词： discotic liquid crystal triphenylene semi-fluorinated ester chain columnar mesophase fluorophobic effect molecular symmetry

Disk-shaped Symmetric Hexa-substituted triphenylene Derivatives： Synthesis, Physical Properties and Self-assembly

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Chemical Research in Chinese Universities 2013年第3期29卷 495-499页

作者： WANG Dong MI Yong-sheng TANG Jian-kai LIANG Peng-xia JIN Zhao-kui YANG Zhou YANG Huai Department of Materials Physics and Chemistry School of Materials Science and Engineering University of Science and Technology Beijing Beijing 100083 P R. China

A series of triphenylene derivatives with six symmetric substituents was synthesized from hexabromotriphenylene. The synthesis was conducted by six-fold palladium-catalyzed Hagihara-Sonogashira crosscoupling reactions to yield the hexa-alkynyl substituted triphenylene derivatives of HTPI, HTP2, HTP3 and HTP4. The six symmetric substituents can not only endow the triphenylene the longer π-conjugated range, but also increase the solubility of the compounds. Their photophysical, electrochemical, thermal properties were investigated respectively. With the comparison of their properties, the structure-property relationships were established which demonstrated the influences of different substituents on the electronic nature and the mesomorphic phase of these disk-shaped molecules. In addition, with the scanning electron microscopy（SEM） and polarized optical microscopy（POM） characterization, the self-assembly behaviors of the compounds were also investigated.

关键词： triphenylene π-Conjugated range Photophysical property Electrochemical property Self-assembly

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

Synthesis of New triphenylene-containing Discotic Liquid Crystals and the Influence of Fluorophilic Effect and Molecular Symmetry on Mesomorphism

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Chinese Journal of Chemistry 2005年第6期23卷 767-774页

作者：赵可清汪必琴胡平李权张良辅 CollegeofChemistry SichuanNormalUniversityChengduSichuan610066China

New symmetrical and asymmetrical triphenylene‐containing discotic liquid crystals with two different peripheral alkyl chains, known as sym ‐TP(OC 6 H 13 ) 3 (OR) 3 and asym ‐TP(OC 6 H 13 ) 3 (OR) 3 , were synthesized. Their thermotropic liquid crystal properties were investigated through polarizing optical microscopy (POM), differential scanning calorimetry (DSC) and X‐ray diffraction (XRD) analyses. The asymmetrical discogens are 2,6,11‐trialkoxy‐3,7,10‐trihexyloxytriphenylenes, with the alkyl chain carbon numbers varying from 3‐10, 12, and 14, while the symmetrical compounds are 2,6,10‐trialkyloxy‐3,7,11‐trihexyloxytriphenylene. Two fluoroalkoxy substituted triphenylene discogens, 2,6,10‐tri(4,4,4‐trifluorobutoxy)‐3,7,11‐trihexyloxytriphenylene and its asymmetrical isomer 2,6,11‐tri(4,4,4‐trifluorobutoxy)‐3,7,10‐trihexyloxytriphenylene were prepared. These two compounds show higher melting and clearing points than their alkoxy analogs, which implies that fluorophilic effect exists in the formation and stabilization of discotic columnar mesophase. The triphenylene derivatives TP(OC 6 H 13 ) 3 (OR) 3 with two different peripheral chains, symmetrically or asymmetrically attached on triphenylene cores, have lower melting points and clearing points than those of the higher symmetrical compounds TP(OR) 6 with the same total chain carbon numbers. The mixed‐chain‐triphenylenes with longer alkoxy chains ( n =9, 10, 12, 14) show columnar mesophase at room temperature.

关键词： triphenylene discotic liquid crystal columnar molecular symmetry fluorophilic effect

Synthesis of functionalized triphenylene discotic liquid crystals and the influence of unsaturated periphery on mesomorphism

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Science China Chemistry 2011年第10期54卷 1576-1583页

作者： ZHAO KeQing ZHOU Hui YU WenHao HU Ping WANG BiQin MONOBE Hirosato SHIMIZU Yo College of Chemistry and Materials Science Sichuan Normal University Chengdu 610066 China National Institute of Advanced Industrial Science and Technology Kansai Centre Midorigaoka lkeda Osaka 563-8577 Japan

Twelve triphenylene discogens with unsaturated periphery (abbreviated as C18H6(OC5H11)6-x(OR)x(x=1,2,3), R=-C3H6CH==CH2(a),-C3H6C≡CH(b),-C2H4OCH==CH2(c)) were synthesized and characterized. The thermotropic liquid crystal prop-erties were studied by using polarized optical microscopy, differential scanning calorimetry and X-ray diffractometry. The results showed that all triphenylenes exhibited hexagonal columnar mesophase. The thermotropic studies showed that series a (alkene periphery) exhibited higher clearing points than the corresponding series b (alkyne periphery), while series c (vinyloxy periphery) exhibited highest clearing points and widest mesophase temperature ranges. We also found that the symmetric discogens sym-C18H6(OC5H11)3(OR)3 displayed higher melting points and clearing points than the asymmetric ones asym-C18H6(OC5H11)3(OR)3.

关键词： discotic liquid crystal triphenylene functional periphery hexagonal columnar mesophase mesomorphism engineering

Synthesis and mesomorphism of diacetylene-bridged triphenylene discotic liquid crystal dimers

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Science China Chemistry 2009年第7期52卷 975-985页

作者： JI Hong ZHAO KeQing YU WenHao WANG BiQin HU Pin College of Chemistry and Materials Science Sichuan Normal UniversityChengdu 610066China

Connecting two discotic mesogens via a spacer not only stabilizes the columnar mesophase but also leads to the formation of glass columnar phase, and therefore improves the physical properties of discotic liquid crystals as organic semiconductor. Here, we report the synthesis of eight diacetylene-bridged triphenylene discotic liquid crystal dimers, [C18H6(OC n H2n+1)4(OMe)O2C?C8H16?C≡C?]2, 3(n), (n = 4–8), [C18H6(OC6H13)5O2C?C8H16?C≡C?]2, 6 and [C18H6(OC6H13)5O?(CH2)m?C≡C?]2, 8(m), (m = 1, 3) by Eglinton coupling reaction. The thermotropic liquid crystal properties were studied by differential scanning calorimetry and polarized optical microscopy. The results are showed as follows: the length of peripheral alkyl chains of triphenylene influenced properties of liquid crystal dimers; dimers 3(n) (n = 5–8) and 6 had glass columnar phase, and no crystallization was observed above ?50°C for all the triphenylene dimers; compared with 3(6), 6 showed higher molecular symmetry, more stable columnar mesophase and wider mesophase range. The connecting group, length and rigidity of spacer had important influence on the mesomorphism of diacetylene-bridged triphenylene discotic liquid crystal dimers.

关键词： triphenylene discotic liquid crystal Eglinton coupling reaction liquid crystal dimer glass columnar phase

Synthesis and Liquid Crystalline Behavior of Side Chain Liquid Crystalline Polymers Containing triphenylene Discotic Mesogens with Different Length Flexible Spacers

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Chinese Journal of Polymer Science 2015年第9期33卷 1245-1259页

作者： Jian-feng Ban 陈盛张海良 Key Laboratory of Polymeric Materials and Application Technology of Hunan Province Key Laboratory of Advanced Functional Polymer Materials of Colleges and Universities of Hunan Province College of Chemistry Xiangtan University

A series of side chain liquid crystalline polymers （SCLCPs） containing triphenylene （Tp） units in the side chains, denoted as PMTS （without spacer） and PMTnS （n = 2, 3, 4, 6, which is the number of the methylene units between the main chain and Tp moieties in the side chains）, with different lengths of spacers were synthesized through conventional free radical polymerization. The chemical structures of the monomers were confirmed by 1H/IaC-NMR, and the phase behaviors were examined by differential scanning calorimetry （DSC）, polarized optical microscopy （POM） and wide-angle X-ray diffraction （1D and 2D WAXD）. The molecular characterization of the polymers was performed with 1H-NMR, gel permeation chromatography （GPC） and thermogravimetric analysis （TGA）. The phase behaviors of the polymers have been investigated by a combination of techniques including DSC, POM, 1D and 2D WAXD. The results showed that the length of spacer has significant effects on the LC phase behavior of polymers. For PMTS and PMT2S, they displayed the columnar phase developed by the Tp moieties and the main chain as a whole due to the strong coupling effect of the Tp moieties and the main chain. For the PMT3S, PMT4S and PMT6S, they formed the symmetry hexagonal columnar （~n） phase owing to the decoupling effect. All of these indicated that the ＂decoupling effect＂ or ＂coupling effect＂ depended on the length of spacers, leading to the different LC phase formation mechanism.

关键词： Liquid crystalline polymer triphenylene Flexible spacer Phase behavior Columnar phase.

Theoretical study on the charge transport properties of triphenylene discogens with a phenylpropionyloxy or 3-phenylpropenoyloxy side chain

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Science China Chemistry 2009年第8期52卷 1192-1197页

作者： CHEN JunRong HUANG ChuRui XU BuYi LI Quan ZHAO KeQing College of Chemistry and Material Science Sichuan Normal UniversityChengdu 610066China

Charge transport is one of the most important properties in organic *** transport properties of triphenylene discogens with a phenylpropionyloxy or 3-phenylpropenoyloxy side chain have been investigated computationally on the basis of semi-classical Marcus *** results show that three triphenylene derivatives have high charge *** compounds have much better electronic mobility than the *** triphenylenes containing 3-phenylpropenoyloxy have better hole mobility,but smaller electronic mobility than the triphenylenes with *** the triphenylene discogens with a phenylpropionyloxy,the longer the alkloxy chains,the better the positive charge transfer rate,but the smaller the negative charge transfer rate.

关键词： triphenylene charge transport discotic liquid crystals phenylpropilate phenylpropenoate

Synthesis of Novel Discotic C_(60)-triphenylene Derivative by 1,3-Dipolar Cycloaddition

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Chemical Research in Chinese Universities 2012年第2期28卷 358-360页

作者： YANG Fa-fu GUO Hong-yu XIE Jian-wei LIU Zhi-qiang XU Bing-ting College of Chemistry and Materials Science Fujian Normal UniversityFuzhou 350007P.R.China Fujian Key Laboratory of Polymer Materials Fujian Normal UniversityFuzhou 350007P.R.China

1 Introduction Fullerene has received considerable attention and a great researching interest due to its unique structure and interesting properties[1―3]. Many functional groups have been introduced, often region- or stereo-selectively, for tuning the physical properties of C60and for constructing supramoleculararchitectures^[4-6].

关键词： C60 triphenylene 1 3-Dipolar cycloaddition Mosophase