INTERNATIONAL JOURNAL OF POLYMER ANALYSIS AND CHARACTERIZATION
·
2023
·
IF 1.9
Xiaohong Hu,Weiwei Jin,Haitao Zhang,Qinyu Qing,Juan Pang
Visible-light-driven azobenzene had been reported by theoretical calculation, but could not be detected by any characterization method due to unstable cis structure. Herein, copolymerization was applied to solve the problem based on a time-dependent characteristic of macromolecular motion. Therefore, two copolymers, namely, MRAA-PEG20 copolymer and MRAA-NIPAM copolymer, were synthesized with a definite segment ratio. Both copolymers had photosensitive groups, which were confirmed by UV-vis spectra. Furthermore, copolymer concentration had a linear relationship with absorbance value at 425 nm. Firstly, blue light as an excitation source to induce the isomerization of copolymers. At the same time, repeated interval irradiation was used to evaluate the fatigue performance of the copolymer. Consequently, both copolymers could quickly transform to their cis isomers upon irradiation, which could be reversible recovered to their trans isomers in operable recovery time after removing irradiation. However, the MRAA-PEG20 copolymer had an obvious photobleaching phenomenon along with the circle index, which did not exist in the MRAA-NIPAM copolymer. Secondly, the effects of excitation light source on isomerization were investigated. It was found that blue light was the most efficient excitation source for both copolymers though other light could also induce trans-to-cis transition. Thirdly, the influence of light intensity and temperature was respectively studied. With increasing of light intensity, the absorbance ratio before and after irradiation monotonously decreased, the irradiation response time shortened and the recovery response time prolonged. Moreover, higher temperature resulted in a higher absorbance ratio, shorter irradiation response time, and shorter recovery response time. Finally, synthesized copolymers had characteristic of pH indicator with a critical point of pH 5.0.
研究领域:
材料科学
·
高分子化学
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DOI
高影响因子
Journal of Physical Chemistry C
·
2022
·
IF 4.177
Jun Han,Qunfei Zheng,Cheng Jin,Shanmin Wang,Ying Liu,Yusheng Zhao,Jinlong Zhu
The comparison of different stereoisomeric organic compounds under high pressure has been less investigated. Here, we chose different stereochemical configurations of cis/trans-stilbene to study the luminescence properties, polymerization reaction, and structural changes at 0–20 GPa by spectroscopy and XRD. No fluorescence enhancement occurred in cis-stilbene due to π–π stacking. At 16 GPa, the IR, UV–vis, and sample color changes show that it undergoes an irreversible polymerization, that C(sp2)–H changes to C(sp2 + sp3)–H. However, trans-stilbene undergoes fluorescence enhancement at 0–4 GPa due to the reduction of the torsion angle of the benzene ring and the C═C bond leading to the formation of rigid planar molecules, which is further confirmed by the IR and XRD results. At 8 GPa, the new peaks in UV–vis and XRD results show the formation of new substances by structural change. However, the structure of trans-stilbene is more stable, which leads to the return to the raw state after releasing the pressure, and a reversible transformation occurs at high pressure. The cis-trans isomerization under high pressure was also briefly investigated by combining heating and laser irradiation. The cis → trans-stilbene transition can only happen under a fixed-range light irradiation, and the trans → cis-stilbene transition could not happen even under irradiation with a 360 nm laser, which may provide a new idea for synthesizing trans isomers with a higher purity.
研究领域:
化学
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材料科学
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DOI
高影响因子
POLYMER
·
2024
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IF 4.1
Minghao Wang,Haomin Yu,Jiawei Jiang,Wencong Xu,Guofeng Xu,Si Wu
Cis-trans isomerism plays a crucial role in regulating the thermal properties and phase transitions of materials, which is essential for the development of advanced functional materials. By influencing melting points and glass transition temperatures, cis-trans isomerism enables precise control over material performance in applications such as thermal sensors, self-healing coatings, thermal sensors, and temperature-responsive films. Here we report the impact of cis-trans isomerism in double bonds on the thermal and phase transitions of oleic acid (OA) and elaidic acid (EA) and their derived polymers, with a focus on glass transition temperature ( T g ) and melting point ( T m ). A series of molecules and copolymers with varying cis and trans double bond ratios are synthesized to examine how these isomeric configurations affect thermal behavior. Thermal and structural properties are characterized using differential scanning calorimetry (DSC) and nuclear magnetic resonance (NMR) spectroscopy. The results show a clear correlation between isomeric composition and the polymers' T g and T m , illustrating that the incorporation of cis-trans isomers can be effectively used to fine-tune thermal properties. This research offers valuable insights into the design of advanced polymeric materials with tailored thermal characteristics, paving the way for applications in various high-performance sectors.
研究领域:
材料科学
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化学
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DOI
高影响因子
ANALYTICAL CHEMISTRY
·
2024
·
IF 6.7
Tianpei Cai,Xinyue Lei,Hai-Bo Shang,Xia Li,Yetong Guo,Li-Xin Wu,Huwei Liu,Donghao Li
Generally, the traditional stationary phase for liquid chromatography is the key part, but with an in situ immutable property, leading to many separation limitations. Based on the former exploration of photosensitive gas chromatography, we successfully prepared a photosensitive monolithic capillary silica column with high light transmission, taking advantage of the reversible cis–trans isomerism of azobenzene. And the cis–trans isomerism has launched an effective, reversible, and precise control on the liquid chromatographic retention behavior just by photoinduction according to the theoretical basis of a good correlation between photoinduction time, trans-azobenzene ratio, and chromatographic retention factor (k) (R2 > 0.9586). In this system, the plausible control mechanism of stationary phase’s polarity is the synergistic effect of the self-molecular polarity difference and the occupation (or release) of polar groups on the stationary phase surface by cis–trans isomerism. Furthermore, a “light control–time ratio cycle” strategy was first reported to maintain an arbitrary ratio of trans-azobenzene corresponding to the polarity gradient of the stationary phase during the whole chromatographic separation process, which is verified by a close correlation of the retention time of the targets and the ratio of light-controlled time (R2 > 0.9977). The “gradient elution” of the targets was also surprisingly realized due to the gradient regulation of stationary phase’s polarity by the programmatic control of alternate light induction and time ratio. This work further advances the practical significance of photosensitive chromatography in “one column for multiple columns”, even “one column for multidimensional chromatography”, and truly provides research foundation for its development in the separation and analysis of complex biological samples.
研究领域:
分析化学
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色谱技术
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DOI
PubMed
高影响因子
FOOD CHEMISTRY
·
2022
·
IF 9.231
Fangling Wu,Xishi Wu,Zhe Li,Di Zhang,Chuan-Fan Ding
Identification of cis/ trans -carbon–carbon double-bond (C C) isomers remain challenging. Herein, a simple and rapid method for the separation and analysis of cis/ trans -maleic acid (MA) and aconitic acid (AA) using Trapped Ion Mobility Spectrometry (TIMS) was developed. α-, β-, γ-cyclodextrin (CD) were served as the separation reagent, slight difference in mobility separation was obtained by [CD-MA/AA-H] - . Specially, with the addition of divalent metal ion (G 2+ ) as coordination metal ion, the separation effect was much increased by [CD-MA/AA + G-H] + , and α-CD has better mobility separation effect than β-/γ-CD. Moreover, chemical calculations revealed the binary and ternary complexes are in the inclusion forms, and microscopic interactions between cis/ trans -MA/AA, CDs, and G 2+ are somewhat different that making their mobility separation. Finally, quantifications of cis/ trans -isomers were analyzed in food samples, with good linearity (R 2 > 0.99) and recoveries obtained from 87.25 % to 100.73 %.
研究领域:
分析化学
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计算化学
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产品关联
DOI
PubMed
高影响因子
CRYSTAL GROWTH & DESIGN
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2024
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IF 3.2
Yujiao Li,Yunan Zhang,Qi An,Jingwen Shi,Lixin Liu
Based on the study of the effect of positional isomerism of coformer functional groups on the cocrystallization and physicochemical properties of the active pharmaceutical ingredients, the impact of cis–trans isomeric butenedioic acid as coformers on the conformation, crystal structure, and its physicochemical properties of marbofloxacin was further explored. In this work, fumaric acid (FA) and maleic acid (MA) with different configurations were chosen as coformers to synthesize the pharmaceutical salt cocrystal (MBF-FA-H2FA) and salt (MBF-MA) of marbofloxacin (MBF), and their structures were fully characterized. Significant differences between the conformations of marbofloxacin in the salt cocrystal and in salt were found. In the salt cocrystal, the N atom of the piperazine group from marbofloxacin is coplanar with the pyridone ring, and the whole is straight like fumaric acid, whereas the marbofloxacin piperazine group in the salt is bent like the maleic acid configuration. Furthermore, the conformational variability of marbofloxacin in the salt cocrystal and the salt resulted in different crystal structures and opposite physicochemical properties. Notably, both multicomponent crystals have a surface hydrophilic intercalation structure. However, the salt cocrystal and salt exhibited different solubility and permeability. Specifically, the MBF-MA salt showed improved solubility and permeability, while the MBF-FA-H2FA salt cocrystal showed a decreased solubility and permeation rate compared to MBF. In addition, in vitro bacterial inhibitory activity assays indicated that the MBF-MA salt has stronger inhibitory activity against Gram-negative and Gram-positive bacterial strains than the MBF-FA-H2FA salt cocrystal and pure MBF.
研究领域:
药学
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晶体学
·
生物化学
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DOI
高影响因子
Materials Today Communications
·
2024
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IF 3.7
Pingping Wu,Xuegang Hao,Yuanyuan Shang,Junchao Liu
Azobenzene, a representative photoresponsive liquid crystal, has extensive applications in fields such as bionic robotics, actuators, artificial muscles, motors, and various functional devices. Photoisomerization ( trans-cis isomerization) is the most important mechanism for its photoresponse. Currently, the isomerization of azobenzene mesogens can be measured through UV–vis absorption spectra, NMR techniques or transient grating methods. Visualization of the trans-cis isomerization of azobenzene mesogens still remains a challenge. In this study, a linear relationship is observed between the absorption intensity of azobenzene mesogens and the stopband shift of azobenzene inverse opals (AZOIOs) films during the isomerization process. This phenomenon can be used to determine the isomerization degree of azobenzene mesogens through the switching of the stopband of the AZOIOs film, enabling the visualization of the azobenzene mesogens’s configuration transition. The results of this study are highly significant for the design and fabrication of novel azobenzene devices.
研究领域:
材料科学
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光学
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化学
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DOI
高影响因子
ANALYTICA CHIMICA ACTA
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2020
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IF 5.977
Xiaoping Zhang,Xiang Ren,Konstantin Chingin,Jiaquan Xu,Xin Yan,Huanwen Chen
We present an approach for the elucidation of C=C bond position and cis/trans isomers, which is achieved by the reaction of ambient water radical cations and double bonds, followed by the fragmentation of epoxide radical cations to generate diagnostic ions in tandem mass spectrometry . Hexenol double bond positional isomers and cis/trans isomers which exhibit different properties and biological functions are characterized as a proof of concept. The merits of the approach include the simplicity of experimental setup, rapid derivatization (within seconds), the obviation of organic solvents , as well as easy spectral interpretation.
研究领域:
分析化学
·
生物化学
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产品关联
DOI
PubMed
高影响因子
FOOD CHEMISTRY
·
2024
·
IF 8.5
Sisi He,Lulu Shi,Zi-Wei Zheng,Fangling Wu,Chuan-Fan Ding
In recent years, fatty acids containing conjugated C Cs have attracted extensive research attention due to their biological activities against human diseases. However, their differentiation is challenging. This study developed a comprehensive analytical solution to accurately differentiate cis/trans- fatty acid isomers using ion mobility mass spectrometry (IM-MS) and theoretical calculations. Cis/trans -fatty acids were mobility-differentiated via simple complexation with 1,5,9-triazacyclododecane (9C3N) or 1,4,8,11-tetraazacyclotetradecane (10C4N) and metal ions , obtaining baseline separation with a peak-to-peak resolution of 0.35–0.92. Moreover, the conformation of the complexes was optimized theoretically, revealing different binding modes between the cis / trans- fatty acid-9C3N/10C4N–metal ion systems, yielding in-depth structural data on the complexes and elucidating the principles of mobility separation. Furthermore, the proposed method was assessed in terms of quantification, accuracy, and precision repeatability. Finally, the method was applied to analyze oil samples. Given its simplicity, speed, and lack of chemical derivatization or chromatographic separation, this technique has potential applications in food analysis .
研究领域:
分析化学
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生物化学
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产品关联
DOI
PubMed
高影响因子
FOOD RESEARCH INTERNATIONAL
·
2024
·
IF 7
Jing Wei,Jingtao Cui,Yanchi Zhou,Tong Li,Qiaozhu Wei,Tian Li,Weimin Zhang
The effects of cis – trans isomerization on the oxidation products of oleic acid (composites and structure characterization) were investigated. The reduction of thermal oxidation reaction of methyl elaidate (ME) was 6.72 % lower than that of methyl oleate (MO), and the oxidation products (core aldehydes) first increased and then decreased with the prolongation of thermal oxidation time. ME exhibited better oxidation stability than MO in free radicals, hydroperoxides, double bonds, aldehydes, and glycerides. The oxidation products were mainly 11-oxo-9-undecenoate (initial stage) and methyl 9-oxononanoate (later stage), following the free radical chain reaction mechanism. The H8 in double bond was more easily dehydrogenated in the chain initiation stage than H11, followed by the formation of core aldehyde through three intermediates and two transition states each pathway. ME required a higher energy barrier (1.3–13.6 kJ/mol) than MO reaction, making it more difficult for ME to undergo thermal oxidation reaction. The transition state 4 and 5 were rate determining steps of chain initiation reaction and proliferation reaction, respectively. This study was of great significance to further control the formation of these trans fats and their oxidation products.
研究领域:
食品科学
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化学动力学
·
脂质氧化
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DOI
PubMed
高影响因子
ADVANCED FUNCTIONAL MATERIALS
·
2025
·
IF 19
Ziqiu Ren,Hanwen Zhang,Xinqi Lu,Xiyue Wang,Xinyu Yuan,Yanlin Song,Na Wang
The operational stability issues of perovskite devices under illumination pose significant challenges for practical applications, attributed to substantial alterations in lattice distortion, defect enrichment, and stress distribution in the excited state. However, most existing modification strategies predominantly focus on defect elimination and chemical transformations at the ground state level, which may not yield the desired outcomes in the excited state. To address this challenge, this study introduces a dynamic management strategy utilizing 4-aminoazobenzene hydrochloride, which exhibits photoinduced cis-trans isomerism, for the buried interface within perovskite devices. Experimental results demonstrate that the isomerized molecules anchored at the buried interface effectively inhibit the formation of photoinduced defects and mitigate interfacial stress accumulation. A comprehensive mechanism of the dynamic management through cis-trans isomerism transformation has been proposed to elucidate the buried interface modification process. Consequently, the device efficiency and operational stability have been markedly enhanced, achieving a peak efficiency of 25.65% and retaining over 92% of its initial efficiency after 1200 h continuous illumination under International Summit on Organic Photovoltaic Stability protocol (ISOS ).
研究领域:
材料科学
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光伏技术
·
化学工程
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产品关联
DOI
高影响因子
Frontiers of Materials Science
·
2018
·Vol. 12
·期 2
·129-138
·
IF 1.478
Ouyang Shenshen,Wang Tao,Zhong Longgang,Wang Shunli,Wang Sheng
Bulk poly( m -phenylene isophthalamide) (PMIA) can achieve flexibility upon dissolution by a LiCl/dimethylacetamide co-solvent, but remains hydrophobic despite the occasional emergence of cis amide groups providing a weak negative charge. In this study, based on the significant surface differences between PMIA membranes processed by nanofiber electrospinning and casting, a series of chemical analyses, in-situ Au nanoparticle depositions, and dye-adsorption experiments revealed that more cis-configuration amide groups appeared on the surface of the electrospun PMIA membrane than on that of the cast membrane. Based on this surface difference, a strategy was proposed to improve the dyeing properties of PMIA by reversibly changing the cis/trans configurations of electrospun and cast membranes. The reversible chain-segment switch mechanism is a novel method for tuning the macroscale properties of polymer materials based on inherent molecular characteristics.
研究领域:
材料科学
·
化学工程
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产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）