APPLIED SURFACE SCIENCE
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2019
·
IF 5.155
Maiyong Zhu,Qi Chen,Jingjing Tang,Wenjing Wei,Songjun Li
The combination of carbon and iron oxide has recently attracted increasing research interest in energy conversion and storage . Here, the hybrid nanostructure with N, S-codoped Fe 3 O 4 supported/embedded on/in N-doped porous carbon (NS-Fe 3 O 4 @N-PC) nanococoon was prepared via direct pyrolysis of core@shell β-FeOOH@Polypyrrole (β-FeOOH@PPy) composite. Benefiting from the synergistic effect of high redox activity of NS-Fe 3 O 4 and excellent electrical conductivity as well as good mechanical stability of N-PC, the obtained NS-Fe 3 O 4 @N-PC exhibited an enhanced specific capacitance of 866 F/g at 1 A/g along with excellent rate capability (383 F/g at 10 A/g) and improved cycling stability (78.2% of initial capacitance retained after 5000 cycles test) while applied as electrode materials of supercapacitor . Significantly, the asymmetric supercapacitor devices assembled using NS-Fe 3 O 4 @N-PC as anodes and commercial carbon nanotubes as cathodes can achieve a large stack energy density of 38.9 Wh/Kg at a stack power density of 700.2 W/Kg along with good stability (only 8.4% decay of initial capacitance after 5000 cycles at 4 A/g). The present work may provide a general approach for fabricating other metal oxide@carbon hybrid nanomaterials for various applications.
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BIOPOLYMERS
·
2019
·Vol. 110
·期 9
·e23318
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IF 1.845
Yan Xiao,Chenna Tang,Yang Chen,Meidong Lang
Stimuli-responsive polymers that can undergo conformational changes with external triggers have enabled themselves as smart materials for various utilizations, among which biodegradability is of particular importance to be engineered for biomedical application. In this study, a thermo and pH dual responsive polypeptide ( N , N -dimethylaminoethyl acrylate-modified poly( l -cysteine)) (PLC- g -DMAEA) was prepared by the combination of N -carboxyanhydride ring-open polymerization and thiol-ene click chemistry. The biodegradable poly( l -cysteine) (PLC) with pendant thiol groups provided an easily clickable backbone for postmodification, which was demonstrated by reacting with a well-known monomer of N , N -dimethylaminoethyl acrylate (DMAEA) to achieve both temperature and pH responsiveness. The irreversible thermo-response of PLC- g -DMAEA could be attributed to the ordered β-sheets formed upon heating, leading to the trapped side groups with poor water accessibility. Moreover, this copolymer precipitated at pH ranging from 7.5 to 9.7, but protonation of tertiary amine groups (pH < 7.5) and salt forming of masked thiol groups (pH > 9.7) rendered it soluble in water. Our results revealed that a ready available vinyl monomer could be easily clicked onto the biodegradable PLC and its stimuli responsiveness would be reserved. Moreover, the primary and secondary structures of PLC might influence the conformation, thus leading to the unique responsive behavior of the resulted copolymer. Graphical
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Asian Journal of Organic Chemistry
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2018
·Vol. 7
·期 12
·2527-2533
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IF 2.496
Wei-Ze Li,Zhong-Xia Wang
Graphical Reaction of quinoline N -oxides and pyridine N -oxides with arylzinc reagents under transition-metal-free conditions was studied. The reaction was carried out in toluene (for quinoline N -oxides) or THF (for pyridine N -oxides) at 100 °C and required 2 equiv. of arylzinc loadings and the presence of 2.5 equiv. of TFAA, affording 2-arylquinolines and 2-arylpyridines, respectively, in 24% to 95% yields. Reaction of quinoline N -oxides and pyridine N -oxides with arylzinc reagents under transition-metal-free conditions was studied. The reaction was carried out in toluene (for quinoline N -oxides) or THF (for pyridine N -oxides) at 100 °C and required 2 equiv. of arylzinc loadings and the presence of 2.5 equiv. of TFAA, affording 2-arylquinolines and 2-arylpyridines, respectively, in 24% to 95% yields. Functional groups OMe, F, Cl, Br, CF 3 , C(O)NH 2 , COOR and NO 2 were tolerated. Mechanistic studies showed that the reaction of quinoline N -oxides proceeded via a 2-arylquinolin-1(2 H )-olate intermediate, and the reaction of pyridine N -oxides via a 5-arylpenta-2,4-dienal oxime intermediate.
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HIGH PERFORMANCE POLYMERS
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2015
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IF 1.286
Yewei Xu,Yi Sun,Yonglin Lei,Jichuan Huo,Lin Zhang
This article presents a convenient polymerization route to synthesize poly(arylene ether)s containing N-arylenebenzimidazolyl groups. The novel polymers were prepared by a catalyst-free nucleophilic substitution reaction, in which the N–H and O–H sites were removed from 2-(2-hydroxyphenyl)-1H-benzimidazole with different activated difluorides containing carbonyl groups in sulfolane. The reaction was carried out in the presence of anhydrous potassium carbonate at 210°C. The structures of the polymers were characterized using Fourier transform infrared spectroscopy, proton nuclear magnetic resonance spectroscopy, and elemental analysis. The results show good agreement with the proposed structure. All resulting polymers show essentially amorphous patterns. Moreover, differential scanning calorimetry and thermogravimetric measurements show that the polymers have high glass transition temperatures (>209°C), good thermostability, and high decomposition temperatures (>425°C). Furthermore, the polymers also exhibit excellent solubility in common organic solvents.
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BIOORGANIC & MEDICINAL CHEMISTRY
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2013
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IF 2.903
Xiu Liu,Ling Zhang,Jin-Guo Tan,Han-Hong Xu
Based on the discovery of thymine as an ecdysteroid agonist, a series of 1,4-disubstituted diacylhydrazine derivatives with a thymine moiety were designed and synthesized. The activities of these compounds against Spodoptera litura (Fabricius) were evaluated by the insect immersion method. Results showed that compound 2h with an N -cyclohexylmethyl substituent exhibits the most potent agonist activity with a median lethal concentration of 23.21 μg/mL. This compound also caused malformation of molting larvae and adults. Compound 2h was further demonstrated as an ecdysteroid agonist by reporter gene assay on the Spodoptera frugiperda cell line (Sf9 cells). A molecular docking study indicated that hydrophobic interactions and the formation of hydrogen bonds between the compounds and the ecdysone receptor play critical roles in promoting the binding affinity of the compound. The structure of compound 2h may serve as a favorable template for the development of new ecdysteroid agonists with a pyrimidinedione moiety.
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JOURNAL OF CHEMICAL AND ENGINEERING DATA
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2017
·
IF 2.323
Dong-Fang Zhao,Li-Sheng Wang,Jian Sun,Chuan-Ming Chen
A phosphorus flame retardant named N,N′-piperazinebis(neopentylglycol)phosphoramidate (PBNGP) was synthesized and characterized by elemental analysis, Fourier transform infrared spectroscopy, mass spectra, and nuclear magnetic resonance. Its thermal properties were evaluated via thermogravimetric analysis and differential scanning calorimetry. The solubilities of PBNGP in selected solvents at T = (293.15 to 333.15) K and atmospheric pressure were measured via a static-analytic method. The experimental data were correlated with Scatchard–Hildebrand, Buchowski-Ksiazczak, Wilson, nonrandom two liquid, and universal quasichemical equations. The calculated results showed that all of these models can reproduce the experimental data well, and the Wilson model gives the best correlation, with an overall relative standard deviation of 0.70%. The solubility parameter of PBNGP was calculated using the Scatchard–Hildebrand methodology.
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SEPARATION AND PURIFICATION TECHNOLOGY
·
2024
·
IF 8.1
Hao Jiang,Mei Yan,Hao Chen,Xue Chen,Yutuo Fu,Chongshen Guo
How to make full use of solar energy and improve the efficiency of charges separation of photocatalysis has been a concern for scientists all along. To achieve this, this work designed an n-n + homojunction of S-doped SnFe 2 O 4 and applied it to near infrared driven photocatalytic degradation and sterilization. The experimental results demonstrated that S doping significantly enhanced the photocatalytic performance of SnFe 2 O 4 . The degradation rate of ciprofloxacin and the removal rate of Staphylococcus aureus ( S. aureus ) reached up to approximately 65 % and 100 % after 6 h irradiation, respectively. The S-doping could increase the content of shallow trap states in SnFe 2 O 4 , effectively inhibiting the recombination of photogenerated electrons and holes. Moreover, S-doping also enhances the n-type character and forms n-n + homojunction. This n-n + homojunction generates a built-in electric field within the sample, which causes band bending and promotes photogenerated charges transfer and separation. Consequently, more carries are available for the generation of reactive oxygen species. Free radical quenching experiments and ESR tests show that •O 2 − is the main free radical in the photocatalysis. In addition, DFT calculations confirmed the enhanced activation of O 2 after S doping. This work provides a feasible way to effectively promote charges separation and transfer in metalloid-based photocatalysts.
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ELECTROCHIMICA ACTA
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2011
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IF 3.65
Yan Liang,Hongyun Liu,Kaina Zhang,Naifei Hu
N,N-diethylacrylamide (DEA) and 4-vinylpyridine (4VP) were polymerized into P(DEA-co-4VP) copolymer hydrogel films with immobilized glucose oxidase (GOD) on electrode surface with the simple one-step procedure under mild conditions, designed as P(DEA-co-4VP)-GOD. Cyclic voltammetric (CV) response of ferrocenedicarboxylic acid (Fc(COOH) 2 ) probe at P(DEA-co-4VP)-GOD film electrodes was very sensitive to environmental pH, temperature, and sulfate concentration. For example, in pH 5.0 buffers, the CV response of Fc(COOH) 2 was quasi-reversible with quite large peak heights at 25 °C for the films, showing the on state; while at pH 9.0, the peaks were greatly suppressed and the system was at the off state. This pH-sensitive on-off switching behavior of the films toward the probe was reversible and could be repeated for many times between pH 5.0 and 9.0. Similarly, the film system could be switched on-off reversibly when the temperature was changed between 25 and 39 °C, or when the concentration of Na 2 SO 4 was changed between 0 and 0.50 M. This triply responsive property could be further used to realize triply switchable electrochemical oxidation of glucose catalyzed by GOD immobilized in the films and mediated by Fc(COOH) 2 in solution. The responsive mechanism of the system was also explored and discussed. The pH-sensitive property was attributed to the electrostatic interaction between the P4VP component of the films and the probe at different pH, while the thermo- and sulfate-sensitive behavior was ascribed to the structure change of PDEA constituent of the films with temperature and Na 2 SO 4 concentration, respectively. These “smart” films combine the unique stimuli-responsive properties of both P4VP and PDEA with enzymatic reactions and may be used to fabricate a novel type of multi-controllable electrochemical biosensors based on bioelectrocatalysis.
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Soft Matter
·
2024
·Vol. 20
·期 37
·7448-7456
·
IF 2.9
Cuihong Ma,Cong Du,Qing Bo Tong,Xin Ning Zhang,Miao Du,Qiang Zheng,Zi Liang Wu
Incorporating associative interactions as the energy dissipation units has been recognized as an effective strategy to develop tough hydrogels. For hydrogen-bond associations, however, it is highly challenging to stabilize them under aqueous conditions. Although affording cooperativity can enhance and stabilize the hydrogen bonds, it usually requires stepwise polymerization to form these cooperative associations between different polymers and networks. Here, we report a series of tough supramolecular hydrogels with robust hydrogen-bond associations between grafted polymers that are synthesized by polymerization of a macromonomer of poly(N,N-dimethylacrylamide) (PDMAA) and a small monomer of methacrylic acid. The grafted chains of PDMAA form cooperative hydrogen bonds with the main chain of poly(methacrylic acid) (PMAAc), forming supramolecular hydrogels with high toughness and good stability. The tough and stiff hydrogels are in a glassy state, exhibit forced elastic deformation at room temperature, and remain stable over a wide pH range. In contrast, hydrogels prepared by the copolymerization of DMAA and MAAc are swollen and weak in water due to the lack of successive hydrogen donor/acceptor units and the absence of cooperative hydrogen bonds. In addition, these tough hydrogels exhibit good recyclability and shape memory properties, owing to the supramolecular nature of the network and the temperature-dependent mechanical properties. The influence of polymer structure on the associative interactions and macroscopic properties of the hydrogels should be informative for the design of tough soft materials with versatile applications.
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Journal of Energy Chemistry
·
2024
·
IF 14
Yutong Jing,Qiang Lv,Yujia Chen,Bo Wang,Bochen Wu,Cheng Li,Shengbo Yang,Zhipeng He,Dianlong Wang,Huakun Liu,Shixue Dou
Polymer solid electrolytes (SPEs) based on the [solvate-Li + ] complex structure have promising prospects in lithium metal batteries (LMBs) due to their unique ion transport mechanism. However, the solvation structure may compromise the mechanical performance and safety, hindering practical application of SPEs. In this work, a composite solid electrolyte (CSE) is designed through the organic-inorganic synergistic interaction among N , N -dimethylformamide (DMF), polycarbonate (PC), and Mg 2 B 2 O 5 in poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP). Flame-retardant Mg 2 B 2 O 5 nanowires provide non-flammability to the prepared CSEs, and the addition of PC improves the dispersion of Mg 2 B 2 O 5 nanowires. Simultaneously, the organic-inorganic synergistic action of PC plasticizer and Mg 2 B 2 O 5 nanowires promotes the dissociation degree of LiTFSI and reduces the crystallinity of PVDF-HFP, enabling rapid Li ion transport. Additionally, Raman spectroscopy and DFT calculations confirm the coordination between Mg atoms in Mg 2 B 2 O 5 and N atoms in DMF, which exhibits Lewis base-like behavior attacking adjacent C–F and C–H bonds in PVDF-HFP while inducing dehydrofluorination of PVDF-HFP. Based on the synergistic coupling of Mg 2 B 2 O 5 , PC, and DMF in the PVDF-HFP matrix, the prepared CSE exhibits superior ion conductivity (9.78×10 −4 S cm −1 ). The assembled Li symmetric cells cycle stably for 3900 h at a current density of 0.1 mA cm −2 without short circuit. The LFP||Li cells assembled with PDL-Mg 2 B 2 O 5 /PC CSEs show excellent rate capability and cycling performance, with a capacity retention of 83.3% after 1000 cycles at 0.5 C. This work provides a novel approach for the practical application of organic-inorganic synergistic CSEs in LMBs.
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JOURNAL OF MOLECULAR STRUCTURE
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2024
·
IF 4
Tianyang Hou,Yuangang Xu,Ze Xu,Xiaopeng Zhang,Ming Lu
The formation of non-metallic pentazolate salts from the combination of simple nitrogen-rich cations with cyclo -N 5 − is expected to be applied in propellants and explosives. In this work, a series of structurally similar cations ([NH 3 CH 3 ] + , [NH 2 (CH 3 ) 2 ] + , [NH(CH 3 ) 3 ] + , and [N(CH 3 ) 4 ] + ) were used to synthesize four cyclo -N 5 − containing energetic salts, and the contribution of crystal stacking mode, hydrogen bonding, C–H··· π and π -stacking interactions in the stabilization of cyclo -N 5 − salts has been investigated by geometrical and Hirshfeld surface analyses as well as theoretical calculations. All salts have been thoroughly characterized by single-crystal X-ray diffraction, infrared (IR), multinuclear NMR ( 1 H and 13 C) spectroscopy, and elemental analysis. The decomposition temperatures of all salts are higher than 75 °C, as measured by thermogravimetric (TG). These compounds all show low sensitivities (IS ≥ 35 J, FS > 360 N) measured by standard BAM methods. Their heats of formation and detonation performances were calculated using the Born–Haber energy cycle and K-J method (“Pilem” program), respectively. This study has great significance for future design and synthesis of cyclo -N 5 − containing energetic materials.
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ACS Applied Materials & Interfaces
·
2025
·
IF 8.2
Long Li,Yan Wu
This study reports a strategy for constructing highly efficient single-atom photocatalysts through the formation of Ni–N chemical bonds. By anchoring Ni single atoms on nitrogen-doped ZnIn2S4 (N-ZIS), we created a localized charge region that enables directed interfacial charge transfer. The newly formed Ni–N bond plays dual roles of significantly enhancing charge carrier separation and prolonging their lifetime, and serving as an efficient electron transfer pathway from N trap states to Ni active sites. Combined experimental characterization and density functional theory (DFT) calculations confirm the unique stabilizing effect of single Ni atoms in the N-ZIS matrix and elucidate the charge transfer mechanism through Ni–N bridges. The optimized 5%Ni–N30-ZIS photocatalyst exhibits exceptional hydrogen evolution performance, surpassing most previously reported ZIS-based systems. This work highlights the crucial importance of precise control over interfacial chemical bonding at the molecular level for achieving efficient spatial charge separation in inorganic photocatalysts, providing insights for the design of high-performance photocatalytic materials.
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