MOLECULAR CRYSTALS AND LIQUID CRYSTALS
·
2017
·
IF 0.571
Anna Ruan,Hongyu Guo,Chuang Yang,Fafu Yang
Series of cyclotriveratrylene (CTV) derivatives with triazole ring and three alkyl groups were prepared by one-pot click condensation in yield of 80–88%. The structures and crown conformations were confirmed by NMR and MS. Their liquid crystalline properties were investigated by DSC, POM and XRD analysis. The studies on mesomorphic properties suggested that the CTV derivatives with pentyl, hexyl or dodecyl groups show no mesophase but the one with octadecyl groups possesses ordered hexagonal columnar mesophase. In comparison with the reported columnar CTV liquid crystals with six alkyl chains at least, the CTV columnar CTV liquid crystal with three alkyl chains was reported for the first time. These results suggested a subtle balance between the number and length of alkyl chains for columnar CTV liquid crystalline behavior.
研究领域:
材料科学
·
化学
✓ 已验证
DOI
高影响因子
Polymer Chemistry
·
2021
·Vol. 12
·期 5
·736-743
·
IF 5.582
Enjie He,Kai Tu,Jiannan Cheng,Huanjun Lu,Lifen Zhang,Zhenping Cheng,Xiulin Zhu
Main-chain liquid crystalline polymers seldom develop into a columnar phase, let alone mesophase transitions between the columnar phase and other phases as the temperature changes. Herein, we present a new series of main-chain liquid crystalline copolymers which consist of strictly alternating rod-like aryl ester core, alkyl chain and perfluoroalkyl segments synthesized by photoinduced step transfer-addition and radical-termination (START) polymerization. The mesophases can be adjusted by changing the length of alkyl chains or perfluoroalkyl segments, which have been fully investigated and simulated in terms of molecular arrangements of molecules. Importantly the resultant liquid crystalline copolymers can present rare reversible phase transitions from a hexagonal columnar phase to a rectangular columnar phase and finally to a smectic phase with temperature increasing.
研究领域:
材料科学
·
高分子化学
✓ 已验证
产品关联
DOI
高影响因子
LIQUID CRYSTALS
·
2017
·
IF 2.661
Xi-Dan Han,Xian-Li Tian,Wen-Hao Yu,Shi-Kai Xiang,Ping Hu,Bi-Qin Wang,Ke-Qing Zhao,Xiao-Zhen Chen,Chun Feng
A comparative study of our established synthetic approaches to hexasubsituted triphenylenes 2,3-dicarboxylic esters containing four identical β-alkoxy and two adjacent β-alkoxycarbonyl side chains shows that the phase behaviours of small-sized discotic liquid crystals can be tailored over a wide range by simply varying the length of the peripheral alkyl chains. All the prepared esters in two series were observed to form a single hexagonal columnar phase, except for Tp4-1 having four β-butyloxy and two adjacent β-methoxycarbonyl chains which displays two columnar mesophase behaviours with a transition from the columnar plastic phase to hexagonal columnar phase. A significant difference between the two mesophase was observed in the variable temperature X-ray diffraction studies, and the mesophase assignment was also confirmed by polarising optical microscopy and differential scanning calorimetry. Moreover, the prepared esters in each series display the general trend of decreasing clearing temperature upon increasing alkoxy or alkoxycarbonyl chains length. The intermediate triphenylene 2,3-dicarboxylic acids were also found not only to exhibit columnar hexagonal mesophase over a narrower temperature range by maintaining high melting and clearing points but also to form organogel on mixing with toluene or dichloromethane with the assistance of hydrogen bonding.
研究领域:
材料科学
·
化学
✓ 已验证
产品关联
DOI
高影响因子
LIQUID CRYSTALS
·
2024
·
IF 2.4
Tao Deng,Hua Yan,Liangbin Lin,Hongyu Guo,Fafu Yang
Although some cyclotriveratrylene (CTV) liquid crystals had been reported, the CTV liquid crystal with high fluorescence in mesophase was not presented up to now. By introducing diphenylacrylonitrile units on CTV skeleton, two CTV derivatives with AIE units (7a and 7b) were prepared for the first time. Their structures and crown conformations were characterised by 1H NMR, 13C NMR, MALDI-MS spectra and elemental analysis. Samples 7a and 7b exhibited the reversible liquid crystalline behaviours with hexagonal columnar mesophase supported by the DSC, POM and XRD analysis. The studies on photophysical properties of samples 7a and 7b suggested the high fluorescence in solid state and mesophase. The absolute fluorescence quantum yield of 7b in mesophase was as high as 0.45. This work not only reported the first CTV liquid crystals with high fluorescence in aggregated state but also provided a good strategy for constructing the novel CTV liquid crystals with excellent fluorescence.
研究领域:
材料化学
·
光学材料
·
分子设计与合成
✓ 已验证
DOI
高影响因子
JOURNAL OF MOLECULAR STRUCTURE
·
2021
·
IF 3.196
Xiaoyi Zhang,Shengjie Jiang,Guoliang Lin,Hongyu Guo,Fafu Yang
In this article, two new tetraphenylethylene- rufigallol-tetraphenylethylene triads 7a and 7b were synthesized in yield of 50%. These compounds were characterized by mass spectrometry, NMR spectroscopy, and elemental analysis. Their mesomorphic behaviors were studied by polarizing optical microscopy, differential scanning calorimetry, and X-ray diffractometry. Investigation of their liquid crystalline behaviors indicated that compounds 7a and 7b possessed the hexagonal columnar mesophase. Compound 7b with dodecyl chains exhibited the low phase transition temperatures and wide range of mesophase temperatures in comparison with compound 7a . Compounds 7a and 7b exhibited excellent aggregation-induced emission in H 2 O/THF solution. The fluorescence quantum yields of these compounds in the solid state were 22% and 16%, respectively. Results from this study suggest that symmetrical trimer was a good approach to construct novel fluorescence columnar liquid crystals.
研究领域:
材料化学
·
有机化学
✓ 已验证
DOI
高影响因子
JOURNAL OF MOLECULAR LIQUIDS
·
2025
·
IF 5.2
Hongyu Guo,Yanling Huang,Liangbin Lin,Shibing Chen,Fafu Yang
A high luminescence asymmetry factor (g lum ) and an excellent luminescence quantum yield in aggregated state are crucial factors for evaluating the application potential of circularly polarized luminescence (CPL) materials, yet achieving both simultaneously remains challenging. In this work, two AIE-active fluorogens based on two conjugated cyano-distyrylbenzenes attaching one or two cholesterol moieties with amide groups as spacers ( BiCDB-1Ch and BiCDB-2Ch ) were designed and synthesized. Both BiCDB-1Ch and BiCDB-2Ch showed the excellent CPL properties in aggregated states based on their hydrogen-bonding columnar liquid crystalline self-assembly. The absolute fluorescence quantum yield of BiCDB-1Ch with stronger D-A structure was 0.43 and the g lum value was as high as 0.30, which was the highest one among the reported columnar CPL liquid crystals. The detailed liquid crystalline self-assembly behaviour and the mechanism of efficient chirality transfer and amplification were elucidated, providing a strategic approach for developing the novel liquid crystalline materials with superior CPL performance.
研究领域:
材料科学
·
光学
·
有机化学
✓ 已验证
DOI
高影响因子
JOURNAL OF MOLECULAR LIQUIDS
·
2021
·
IF 6.165
Hongyu Guo,Qi Yu,Yuzhi Xiong,Fafu Yang
The first ionic liquid crystals with circularly polarized luminescence were observed based on diphenylacrylonitrile-imidazole salts bearing chiral alkyl chains. Their ordered spiral hexagonal columnar mesophase with long alkyl chains leaded to the effective chiral transfer and chiroptical amplification, resulting in high luminescence dissymmetry factors.
研究领域:
材料科学
·
光学
·
分子化学
✓ 已验证
DOI
高影响因子
LIQUID CRYSTALS
·
2021
·
IF 0
Wenquan Li,Ying Chen,Yanying Ye,Hongyu Guo,Fafu Yang
This paper reported the first triphenylene-fluorescein-triphenylene trimers (3a and 3b), which exhibited stable hexagonal columnar mesophase and good fluorescence in comparison with the similar triphenylene-fluorescein dimers. The trimers 3a and 3b bridged by -C3H6- and -C6H12- group were conveniently prepared in yields of 67% and 73%. They exhibited the stable hexagonal columnar mesophase, high fluorescence quantum yields, and the large Stokes shifts due to the influence of two triphenylene units. The highest fluorescence quantum yield attained 0.91 for 3b and the largest Stokes shift reached 105 nm for 3a. This work revealed that trimers were a good strategy to construct novel columnar liquid crystals with stable columnar mesophase and high fluorescence.
研究领域:
材料科学
·
化学
✓ 已验证
DOI
NEW JOURNAL OF CHEMISTRY
·
2021
·Vol. 46
·期 3
·1168-1174
·
IF 3.591
Hongyu Guo,Xue Wang,Wenchao Zhou,Fafu Yang
Although various perylene derivatives have been studied widely, circularly polarized luminescence (CPL) perylenes in the aggregated state are seldom presented due to the ACQ effect. In this study, a novel diphenylacrylonitrile–perylene derivative with peripheral chiral alkyl chains (CPL-P) was designed and prepared in 81% yield. CPL-P showed Colh mesophase with a wide mesomorphic temperature ranging from 42.8 °C to 155.6 °C. Its photophysical studies suggested good fluorescence emission (550–700 nm) in the aggregated state due to the AIE-FRET effect between the diphenylacrylonitrile unit and perylene skeleton. The chiral optical investigation implied that CPL-P exhibited excellent CPL emission in the aggregated state, which could be attributed to the favourable influence of the AIE-FRET effect and the effective chiral transfer from chiral alkyl chains to the perylene skeleton based on the spiral columnar mesophase. This work not only presents a novel perylene derivative with a good CPL property in the aggregated state, but also opens a new strategy of combining the AIE-FRET effect and chiral transfer based on mesomorphic self-assembly to construct normal dye derivatives with excellent CPL property in the aggregated state.
研究领域:
材料化学
·
光学材料
✓ 已验证
DOI
高影响因子
DYES AND PIGMENTS
·
2017
·
IF 3.473
Mingguang Zhu,Youzhen Zhuo,Kaicong Cai,Hongyu Guo,Fafu Yang
A novel perylene liquid crystal with diphenylacrylonitrile groups on 1,7-bay positions was synthesized in high yield. This highly decorated perylene bisimide showed the ordered hexagonal columnar liquid crystalline behaviour between 124.9 and 189.5 °C. Upon excitation of 480 nm, an attenuation of fluorescent intensity was observed with the increase of water fraction in THF/H 2 O mixtures. However, the fluorescence intensity enhanced dramatically and attained a maximum value at water fraction of 40% in THF/H 2 O systems when excited at 330 nm. The fluorescence intensity increased by 10 times and the pseudo Stokes shift achieved 251 nm. These phenomena were well elucidated by the AIE and FRET effect, which were supported by the investigation of fluorescence quantum yield and fluorescence lifetime .
研究领域:
材料科学
·
化学
·
光学
✓ 已验证
产品关联
DOI
高影响因子
LIQUID CRYSTALS
·
2017
·
IF 2.661
Cheng-Yan Gan,Jing Zhou,Wen-Hao Yu,Shi-Kai Xiang,Lai-Cai Li,Bi-Qin Wang,Ping Hu,Ke-Qing Zhao,Xiao-Zhen Chen,Chun Feng
Hexasubstituted triphenylene (1a) containing four alkoxy and two adjacent methoxycarbonyl tails can be smoothly brominated or nitrated at its α-position(s) of two electron-rich rings to give a series of bromides and nitro compounds through electrophilic aromatic substitutions. Positions of bromo or nitro groups in target compounds were unambiguously established by combined analysis of 2D nuclear magnetic resonance experiments including nuclear Overhauser effect and heteronuclear multiple-bond correlation which indicated that monobromination or mononitration occurred preferentially at position 8 or 5 of 1a, respectively. Calculations of molecular geometry on 2a–e reveal that the α-Br or α-NO2 group(s) would induce different degrees of helical deformation in the triphenylene core and the degree of non-planarity decrease in the following order: 2c > 2b > 2e > 2a > 2d. In contrast to highly twisted 2b–c and 2e, which did not form a mesophase, the formation of a hexagonal columnar phase at room temperature even down to −50°C was observed and confirmed by polarising optical microscopy and X-ray diffraction for sterically less hindered, monosubstituted 2a and 2d.
研究领域:
材料科学
·
化学
·
液晶
✓ 已验证
产品关联
DOI
高影响因子
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