LIQUID CRYSTALS
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2020
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IF 2.908
Guoqing Liu,Liyuan Ren,Mengting Zhang,Shenghua Du,Pei Chen,Aiai Gao,Xinbing Chen,Zhongwei An
Series of heterocyclic compounds containing ethynyl group, 2-[4-[2-[4-(alkoxy)phenyl]ethynyl]phenyl] -benzoxazole derivatives (nPEPBx), are prepared and investigated. They display enantiotropic nematic and smectic mesophases with large mesophase ranges of 30–133°C (heating) and 31–141°C (cooling). Compared with reference analogues without ethynyl group, the compounds nPEPBx roughly give lower melting points and much higher nematic mesophase stability because of the introduction of triple carbon-carbon bond. Meanwhile, they show much higher birefringence (Δn, 0.50–0.65 and 0.55–0.68 for experimental and calculated values with density functional theory (DFT), respectively) than common tolane-based liquid crystals, which indicates that the introduction of benzoxazole unit is an effective method to enhance Δn values of the rod-like molecule. It is concluded that nPEPBx has a potential application in liquid crystal mixture as a dopant to enhance the performance of the host mixture.
研究领域:
材料化学
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液晶物理
✓ 已验证
DOI
高影响因子
LIQUID CRYSTALS
·
2020
·
IF 2.908
Jiazhen Dang,Shenghua Du,Liyuan Ren,Mengting Zhang,Pei Chen,Aiai Gao,Weisong Du,Xinbing Chen,Zhongwei An
Heterocyclic mesogenic compounds are one of the interesting liquid crystals. Here, a series of 1-methyl-1H- benzimidazole-based mesogenic compounds incorporating ethynyl moiety, 2-[4-[2-[4-(alkoxy)phenyl]ethynyl]phenyl]-1-methyl-1H-1,3-benzimidazole derivatives (nPEPMx) with terminal groups of H, CH3 and NO2 (coded as nPEPMH, nPEPMM and nPEPMN, respectively), are synthesised and their properties are evaluated. It is noted that the compounds nPEPMx with short alkoxy chain less than 9 carbon atoms display enantiotropic nematic mesophases, whereas corresponding reference compounds without ethynyl moiety have enantiotropic smectic mesophases. The mesophase ranges of compounds nPEPMx 50–70°C and 55–108°C on heating and cooling for nPEPMH, 76–106°C and 98–142°C for nPEPMM, and 78–132°C and 130–166°C for nPEPMN, respectively. Besides, compounds nPEPMx show obviously large birefringence of 0.501–0.641, suggesting a potential application in liquid crystal mixture. The high birefringence may result from its large π-conjugated molecule structure incorporating ethynyl and benzimidazole π-conjugated mesogenic unit.
研究领域:
材料化学
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液晶科学
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有机合成化学
✓ 已验证
DOI
高影响因子
LIQUID CRYSTALS
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2020
·
IF 2.908
Shenghua Du,Mengting Zhang,Pei Chen,Jiazhen Dang,Aiai Gao,Weisong Du,Xinbing Chen,Zhongwei An
With altering molecular dipole moments via lateral fluoro atom and π-conjugation through carbon–carbon triple bond, improved mesomorphic behaviour is achieved for new kind of fluorinated mesogenic compounds containing ethynyl and 1-methyl-1H-benzimidazole moieties, namely, 2-[4-[2-[4-(alkoxy) phenyl]ethynyl]-3-fluorophenyl]-1-methyl-1H-benzimidazole derivatives (nPEF(3)PMx). The compounds nPEF(3)PMx mainly display enantiotropic nematic mesophases with mesophase ranges of 27.1–59.1 °C and 62.7–96.7°C on heating and cooling for nPEF(3)PMH, 59.499.1°C and 96.2–144.6°C for nPEF(3)PMM, and 101.6–109.4°C and 104.9–157.2°C for nPEF(3)PMN (n < 8), respectively. Compared with nonfluorinated reference analogues I, nPEF(3)PMx give obviously lower melting points and much wider or comparable nematic mesophase ranges, meanwhile, they show much lower melting points and higher nematic mesophase stability than reference analogues II because of their reduced molecular dipole moments and enhanced π-conjugation. In addition, the compounds nPEF(3)PMx are composed of benzene ring, ethynyl bridge and benzimidazole mesogenic unit, therefore, they have high birefringence of 0.48–0.62 resulted from their large π-conjugated molecule. The result indicates that nPEF(3)PMx has a potential application in liquid crystal mixture.
研究领域:
材料科学
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化学
✓ 已验证
产品关联
DOI
高影响因子
POLYMER
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2017
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IF 3.684
Hongyan Yao,Na Zhang,Kunzhi Shen,Ningning Song,Kaixiang Shi,Shiyang Zhu,Yunhe Zhang,Shaowei Guan
A dianhydride monomer 2, 5-bis(3, 4-dicarboxyphenoxy)-4′-phenylethynyl biphenyl (PEPHQDA) containing a chain extendable phenylethynyl pendant group has been successfully synthesized via successive nucleophilic substitution , Sonogashira cross-coupling, hydrolysis and dehydration reactions. A flexible microporous polyimide network has been prepared based on the use of triamine (TAPOB), affording hyperbranched polyimide, followed by the curing of phenylethynyl groups to give network structure. Specifically microporous features such as a well-defined surface morphology , microporous structure and nanometer-sized pore channels have been introduced to the flexible polyimide networks through this two-step pathway. This network exhibit a BET surface area (322 m 2 g −1 ) as well as a comparable CO 2 uptake (1.25 mmol g −1 at 273 K and 1 bar) and enthalpy of adsorption (30.3 kJ mol −1 ) to that of other microporous polyimides derived from rigid tridimensional monomers.
研究领域:
高分子科学
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材料科学
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环境科学
✓ 已验证
产品关联
DOI
高影响因子
SENSORS AND ACTUATORS B-CHEMICAL
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2021
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IF 7.46
Qian Liu,Fang Wu,Huixia Di,Yingna Bi,Meng Meng,Dingbin Liu,Yongmei Yin,Rimo Xi
Developing highly sensitive and specific method is essential for trace Hg 2+ quantifying. Herein, we established a background-free surface-enhanced Raman scattering (SERS) platform which allows not only the detection of Hg 2+ in homogeneous samples, but also high-precision profiling of Hg 2+ distribution in zebrafish. Its superior anti-interference capability is due to the introduction of a high signal-to-noise-ratio (SNR) Raman reporter with an acetylenyl group, which present single nonoverlapping peak at 2125 cm −1 , avoiding interference from other substances. Additionally, the specific recognition of Hg 2+ -bis-thymine complexes and the signal amplified hybridization chain reaction (HCR) were effectively utilized in this design. Benefited from the above strategies, a detection range for Hg 2+ from 1.0 fM to 100 pM was achieved with a detection limit of 0.2 fM. Additionally, Raman imaging was first performed in zebrafish sections to study Hg 2+ distribution which provided a reference for the detection of Hg 2+ pollution in fish. This approach could be extended to target other interested analytes both in simple and biological samples for various purposes.
研究领域:
分析化学
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环境科学
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生物技术
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）