LIQUID CRYSTALS
·
2022
·
IF 2.676
Tong Zhang,Yuyu He,Fanghua Liang,Ran Chen,Pei Chen,Xinbing Chen,Zhongwei An
A series of benzimidazole-based liquid crystal compounds containing laterally difluoro-substituted and ethynyl linking groups, namely, 2-(4-(2-(2,3-difluoro-4-(alkoxy) phenyl)ethynyl)phenyl)-1-methyl-1 H-benzimidazolem derivatives (nPF(2,3)EPMx), are synthesised and investigated for their mesomorphic properties. These compounds mainly display enantiotropic nematic mesophases in the ranges of 32.0–44.5°C (heating process) and 50.0–64.0°C (cooling process). 10PF(2,3)EPMx exhibits lower clearing points and broader nematic phase ranges than nonfluorinated reference compound 10PEPMx, because of their slightly increased dipole moment. nPF(2,3)EPMx displays much larger theoretical birefringence (0.43–0.55) and experimental birefringence (0.42–0.53) than the common tolane-based liquid crystals, which is ascribed to its large π-conjugated molecule composed of benzene core, ethynyl linking group and benzimidazole terminated unit. The theory results of three-dimensional molecular conformations with dipole moment (µ), ratio of length to width (L/W), polarisability anisotropy (Δα) and average polarisability (Δα) calculated with density functional theory are also helpful in explaining the experimental results.
研究领域:
材料科学
·
化学
✓ 已验证
DOI
高影响因子
BIOSENSORS & BIOELECTRONICS
·
2014
·
IF 6.451
Jian Rong Zhang,Wei Tao Huang,Ai Lian Zeng,Hong Qun Luo,Nian Bing Li
Ethynyl triggered enhanced fluorescence quenching effect was first reported based on photoinduced electron transfer (PET) between fluorophore and ethynyl. Ethynyl and 6-carboxyl-fluorescein (FAM) were labeled at the 5′- and 3′-termini of a poly d(T) sequence containing three thymine units, respectively. In the presence of Hg 2+ , Hg 2+ binds to two thymine residues through T–Hg 2+ –T interactions and the formed T–Hg 2+ –T base pairs bring FAM and ethynyl from two matched sequences into close proximity . On the one hand, π-stacked T–Hg 2+ –T mediates and accepts electron transfer of the excited state of FAM and quenches the fluorescence through PET. On the other hand, π-stacked interactions between ethynyl and FAM also provide a de-excitation process for the excited state of FAM via PET and trigger an enhanced fluorescence quenching. On the basis of fluorescence quenching, a simple, rapid, and sensitive Hg 2+ sensor was constructed; under optimum conditions, a good linear relationship was obtained over the concentration range of 5–150 nM for Hg 2+ and a very low detection limit (0.42 nM) was reached. The developed system was further designed as a cysteine (Cys) sensor based on fluorescence recovery resulted from the strong interaction between Cys and Hg 2+ ; the proposed Cys sensor has a linear range of 10–550 nM and a detection limit of 2.5 nM. The two sensors were used for analysis of real samples and the satisfactory results were achieved.
研究领域:
生物化学
·
分析化学
✓ 已验证
DOI
PubMed
高影响因子
LIQUID CRYSTALS
·
2020
·
IF 2.908
Mengting Zhang,Shenghua Du,Diao Yuan,Pei Chen,Guoqing Liu,Jiazhen Dang,Xinbing Chen,Zhongwei An
New kinds of heterocyclic mesogenic compounds containing benzoxazole, ethynyl, and laterally fluorinated phenyl groups, namely 2-[4-[2-[4-alkoxyphenyl]ethynyl]-2,3-difluorophenyl]-benzoxazole derivatives (nPEDFPBx), are synthesized and evaluated. The compounds nPEDFPBx except nitro-substituted ones have enantiotropic nematic mesophases with mesophase ranges of 16–86°C and 29–108 °C on heating and cooling, respectively. The results show that introduction of two lateral fluorine atoms into molecule results in enhanced nematic mesophase stability. Meanwhile, nPEDFPBx displays much higher birefringence (0.507–0.624) than common tolane-based liquid crystals, which is ascribed to its large π-conjugated molecule composed of benzene, ethynyl, and benzoxazole mesogenic unit. The nPEDFPBx has a high potential to serve as a dopant for liquid crystal mixture.
研究领域:
材料科学
·
化学
✓ 已验证
DOI
高影响因子
REACTIVE & FUNCTIONAL POLYMERS
·
2025
·
IF 5.1
Min Zhong,Weichen Sheng,Jianfeng Chen,Han Zhang,Hongping Li,Kan Zhang
The objective of this paper is to conduct a comparative analysis of sesamol-based benzoxazine monomers derived from anilines with an ethynyl substituent in a different position and to obtain some laws to guide the design of thermosets. The synthesis of bio-benzoxazine monomers (S-a, S- o ea, S- m ea, and S- p ea) via a one-step method from sesamol, a biomass monophenol, in the presence of polyformaldehyde by combining four different amines (aniline, ortho -ethynyl aniline, meta -ethynyl aniline, and para -ethynyl aniline), respectively. The structures of four new benzoxazine monomers were characterized by 1 H NMR, 13 C NMR, 2D-HMQC, and FT IR analysis. The FT IR spectra calculated by Gaussian 16 exhibited a high degree of consistency with the experimental data. The DSC scanning results of the monomers demonstrated that the order of the maximum exothermic peak temperature of polymerization was as follows: S- o ea (198.3 °C) < S- p ea (202.1 °C) < S- m ea (216.8 °C) < S-a (240.2 °C), which is in general agreement with the energy level order of HOMO-LUMO, as determined by Gaussian analysis. In addition, the reaction mechanisms of the oxazine ring and the ethynyl moiety were proposed in conjunction with an investigation of the polymerization process by in-situ FT IR. The TGA and MCC test results showed that the polymers (poly(S- o ea), poly(S- m ea), and poly(S- p ea)) derived from the corresponding monomers with ethynyl substituent in various site exhibit both excellent thermal stability and flame retardancy. Notably, poly(S- p ea) exhibited the highest carbon yield (70.2 %) at 800 °C. The incorporation of the ethynyl group not only reduces the polymerization process of benzoxazine monomers but also enhances the performance of resulting polybenzoxazines. This work offers a valuable reference for the preparation of optimal benzoxazine structures in future research.
研究领域:
材料科学
·
有机化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
·
2017
·
IF 3.154
Dezhen Wang,Wentao Zhu,Yao Wang,Jin Yan,Miaomiao Teng,Jiyan Miao,Zhiqiang Zhou
Previous studies have demonstrated the endocrine disruption of o,p′-DDT. In this study, we used a 1H NMR based metabolomics approach to investigate the estrogenic effects of o,p′-DDT (300 mg/kg) on the uterus and brain after 3 days of oral gavage administration, and ethynylestradiol (EE, 100 μg/kg) was used as a positive control. A supervised statistical analysis (PLS-DA) indicated that o,p′-DDT exerted both estrogenic receptor-(ER)-dependent and independent effects on the uterus but mainly ER-independent effects on the brain at metabolome levels, which was verified by coexposing with the antiestrogenic ICI 182,780. Four changed metabolites—glycine, choline, fumarate, and phenylalanine—were identified as ER-independent alterations in the uterus, while more metabolites, including γ-aminobutyrate, N-acetyl aspartate, and some amino acids, were disturbed based on the ER-independent mechanism in the brain. Together with biological end points, metabolomics is a promising approach to study potential estrogenic chemicals.
研究领域:
毒理学
·
代谢组学
·
内分泌学
✓ 已验证
DOI
高影响因子
CELLULOSE
·
2016
·Vol. 24
·期 2
·591-607
·
IF 3.195
Xiao Guifa,Ding Chunyue,Song Feiyu,Qian Xueren,An Xianhui
A facile strategy for preparation of alkyne-functionalized cellulose fibers with click reactivity is reported herein. Poly(3-ethynylaniline) [poly(3-EA)] with pendant alkynyl groups was obtained by chemical oxidation polymerization of 3-ethynylaniline with ammonium persulfate in low-concentration hydrochloric acid solution at ice-bath temperature and used to generate alkyne-functionalized cellulose fibers in situ from pulp fibres. Successful preparation of alkyne-functionalized cellulose fibers was confirmed by attenuated total reflectance Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, and scanning electron microscopy. The effects of process variables on poly(3-EA) deposition and fiber loss were investigated, and suitable preparation conditions identified. Deposition of poly(3-EA) did not change the crystallinity or hydrophilicity of the cellulose fibers. Poly(3-EA) and alkyne-functionalized cellulose fibers reacted with azides by Cu(I)-catalyzed alkyne–azide 1,3-dipolar cycloaddition. Thus, this in situ chemical polymerization technology provides a new platform for click functionalization of cellulose fibers. Applications of cellulose fibers produced in this way are limited to those without demanding requirements in terms of product strength or color.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
LIQUID CRYSTALS
·
2020
·
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
·
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
·
液晶科学
·
有机合成化学
✓ 已验证
DOI
高影响因子
LETTERS IN ORGANIC CHEMISTRY
·
2024
·Vol. 22
·期 1
·56-60
·
IF 0.7
Xin-Yu Lin,Guo-Jun Chen,Su-Zhe Wu,Ke-Xuan Xu,Xiao-Tian Zhang,Qi Feng
4-Hydroxyquinoline-2(1H)-ones exhibit multiple biological activities, and studying their synthetic methods is of great significance. In the presence of tetramethylguanidine and silver nitrate, 4-hydroxyquinoline-2(1H)-ones were efficiently synthesized from 2-ethynylanilines and carbon dioxide under atmospheric pressure. The reaction conditions, such as types of silver catalysts and reaction solvents, were optimized, and the applicability of the substrate was preliminarily investigated. This method provides an alternative pathway for the synthesis of 4-hydroxyquinoline-2(1H)-ones and the conversion and utilization of carbon dioxide.
研究领域:
有机化学
·
药物化学
✓ 已验证
DOI
高影响因子
LIQUID CRYSTALS
·
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
·
化学
✓ 已验证
产品关联
DOI
高影响因子
INORGANIC CHEMISTRY
·
2012
·
IF 4.601
Yu-Peng Zhou,Mei Zhang,Yu-Hao Li,Qi-Rui Guan,Fang Wang,Zhuo-Jia Lin,Chi-Keung Lam,Xiao-Long Feng,Hsiu-Yi Chao
A series of mononuclear gold(I) acetylide complexes with urea moiety, R′3PAuC≡CC6H4-4-NHC(O)NHC6H4-4-R (R′ = cyclohexyl, R = NO2 (2a), CF3 (2b), Cl (2c), H (2d), CH3 (2e), tBu (2f), OCH3 (2g); R′ = phenyl, R = NO2 (3a), OCH3 (3b); R′ = 4-methoxyphenyl, R = H (4a), OCH3 (4b)), have been synthesized and characterized. The crystal structures of Ph3PAuC≡CC6H4-4-NHC(O)NHC6H4-4-NO2 (3a) and (4-CH3OC6H4)3PAuC≡CC6H4-4-NHC(O)NHC6H5 (4a) have been determined by X-ray diffraction. Complexes 2a–2g, 3b, and 4a–4b show intense luminescence both in the solid state and in degassed THF solution at 298 K. Anion binding properties of complexes 2a–2g, 3a–3b, and 4a–4b have been studied by UV–vis and 1H NMR titration experiments. In general, the log K values of 2a–2g with the same anion in THF depend on the substituent R on the acetylide ligand of 2a–2g: R = NO2 (2a) > CF3 (2b) ≥ Cl (2c) > H (2d) > CH3 (2e) ≈ tBu (2f) ≥ OCH3 (2g). Complex 2a with NO2 group shows the dramatic color change toward F– in DMSO, which provides an access of naked eye detection of F–.
研究领域:
无机化学
·
材料化学
·
分析化学
✓ 已验证
DOI
PubMed
高影响因子
SCIENCE OF THE TOTAL ENVIRONMENT
·
2021
·
IF 7.963
Huan He,Yanting Lin,Xiaoxia Yang,Xintong Zhu,Wenxiao Xie,Chaochao Lai,Shanshan Yang,Zhe Zhang,Bin Huang,Xuejun Pan
17 alpha-ethinylestradiol (EE2) in natural waters can seriously harm ecosystems and human health. Dissolved organic matter (DOM) and iron minerals are ubiquitous in natural waters, and they can shorten the half-life of EE2 in the natural environment. The interaction between dissolved organics and iron affects pollutants' transformation pathways. The mechanism of EE2's adsorption on hematite, magnetite and pyrite was studied. A photo-Fenton system was constructed in which humic acid (HA) and iron minerals degraded EE2 under simulated natural light conditions. Pyrite showed the best adsorption and degradation in acidic conditions (52%) for 5 h. Hydroxyl radical was found to be the main active substance in the photodegradation . The degradation products of EE2 were identified and possible degradation pathways were inferred. These results can contribute to the understanding of the transformation pathways of persistent organic pollutants in natural waters.
研究领域:
环境科学
·
生态学
·
水污染治理
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）