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41.
Jingxin Wang Dr. Yongjie Shi Dr. Fangyuan Wang Dr. Fanping Huang Prof. Dr. Shao-Tao Bai Prof. Dr. Yu Zhao Prof. Dr. Xumu Zhang 《Angewandte Chemie (International ed. in English)》2023,62(25):e202303868
The atom- and step-efficient synthesis of chiral fused tricyclic lactams from readily available ketoesters using cheap ammonium salts as the nitrogen source is reported. This ruthenium-catalyzed system operates through an efficient tandem dynamic kinetic asymmetric reductive amination (ARA)/lactamization and produces chiral fused tricyclic lactams in high yields with excellent diastereo- and enantioselectivity (up to >99 % ee, >20 : 1 dr and 98 % yield). The robust method was also applied to the concise synthesis of key intermediates in the synthesis of rivastigmine analogues and chiral N-heterocyclic carbene catalysts. 相似文献
42.
Enming Du Yueping Jiang Fangyuan Qin Yange Wang Siyu He Gang Wang Zongming Song Junjie Zhang Ye Tao 《Photochemistry and photobiology》2023,99(4):1149-1156
UV-B-induced corneal damage remains a challenge in clinics, and it is needed to develop novel and effective medicines against UV-B induced photodamage. 3,4-Dihydropyrimidine-2(1H)-thione derivatives have shown many interesting biological activities, including antibacterial, anti-inflammatory, antioxidant, etc. In order to find a promising anticorneal photodamage agent, we designed and synthesized two novel sulfonated dihydropyrimidinthione derivatives to evaluate cytoprotective effect against UV-B-mediated photodamage. With simple structure, compound 6 possessed good water solubility, photostability and biocompatibility. We demonstrated that 6 exhibited significant cytoprotective effects against UV-B-mediated photodamage and the cell viability was up to 93% at 0.2 mg mL−1. The corneal cells were highly sensitive to UV-B radiation, resulting in the release of inflammatory mediators and DNA damage, which were significantly reversed by 6. Moreover, compound 6 reduced Bax and cleaved Caspase-3 expressions to suppress UV-B mediated the intrinsic apoptosis pathway. Our findings suggest that 6 is a promising UV-B resistant agent with potential to be a promising drug candidate for the treatment of corneal photodamage. 相似文献
43.
A series of mildly oxidized graphene oxide (MOGO) reinforced polydicyclopentadiene composites (MOGO/polyDCPD) were prepared via the in situ polymerization of DCPD in the presence of MOGO using ring-opening metathesis polymerization (ROMP). The inter-crosslinking networks between MOGO and polyDCPD backbones formed the reinforced composite structures, examined qualitatively by swelling tests. Bending tests, DMA and TGA measurements were employed to study the optimal loading content of MOGO for achieving the best mechanical and thermal properties of MOGO/polyDCPD composites. The results showed that the maximum mechanical performance was achieved with 0.1 wt% of MOGO loading. Excess MOGO led to decreased mechanical properties due to the poor solubility and uneven distribution of MOGO in the polymer matrix, which was confirmed by SEM. Meanwhile, the thermal stability of MOGO/polyDCPD composites showed a similar trend. The decomposition temperature at 10 wt% weight loss was significantly increased compared with the unfilled polyDCPD, but decreased with composition of MOGO above 0.1 wt%. The addition of MOGO may not only inhibit the back-biting from the catalyst and the formation of low molecular weight oligomers in the polymer, but also covalently immobilize them on its flake. 相似文献
44.
Li Y Zhang D Gai F Zhu X Guo YN Ma T Liu Y Huo Q 《Chemical communications (Cambridge, England)》2012,48(64):7946-7948
Metal-organic polyhedra (MOP) nanocages were successfully surface functionalized via ionic self-assembly and the ordered honeycomb architecture of the encapsulated MOP nanocages was also fabricated at the air/water surface. The results provide a novel synthetic method and membrane processing technique of amphiphilic MOP nanocages for various applications. 相似文献
45.
Integrity of functional self-assembled monolayers on hydrogen-terminated silicon-on-insulator wafers
Silicon-on-insulator (SOI) wafers are commonly used to design microelectronics, energy conversion, and sensing devices. Thin solid films on the surfaces of SOI wafers have been a subject of numerous studies. However, SOI wafers modified by self-assembled monolayers (SAMs) that can also be used as functional device platforms have been investigated to a much lesser extent. In the present work, tert-butoxycarbonyl (t-boc, (CH3)3-C-O-C(O)-)-protected 1-amino-10-undecene monolayers were covalently attached to a H-terminated SOI (1 0 0) surface. The modified wafers were characterized by X-ray photoelectron spectroscopy to confirm the stability of the SAM/Si interface and the integrity of the secondary amine in the SAM. The transmission electron microscopy investigation suggested that this t-boc-protected 1-amino-10-undecene SAM produces atomically flat interface with the 2 μm single crystalline silicon of the SOI wafer, that the SiOx and both available Si/SiOx interfaces are preserved, and that the organic monolayers are stable, with apparent thickness of 1.7 nm, which is consistent with the result of the density functional theory modeling of the molecular features within a SAM. 相似文献
46.
Synthesis of Size‐Controlled Ag@Co@Ni/Graphene Core–Shell Nanoparticles for the Catalytic Hydrolysis of Ammonia Borane 下载免费PDF全文
Fangyuan Qiu Li Li Guang Liu Changchang Xu Cuihua An Yanan Xu Ying Wang Yanan Huang Chengcheng Chen Prof. Yijing Wang Lifang Jiao Prof. Huatang Yuan 《化学:亚洲杂志》2014,9(2):487-493
Size‐controlled Ag0.04@Co0.48@Ni0.48 core–shell nanoparticles (NPs) were synthesized by employing graphene (rGO) with different reduction degrees as supports. The number of C?O and C? O functional groups on the surface of rGO might play a major role in controlling the particle size. The strong steric‐hindrance effect of C?O resulted in the growth of large particles, whereas C? O contributed to the formation of small particles. The particle size of Ag0.04@Co0.48@Ni0.48 NPs supported on rGO with different reduction degrees decreased as the number of C?O functional groups decreased. The decrease in the particle size probably led to the increase in the catalytic activity towards the hydrolysis of ammonia borane (AB). The enhanced catalytic activity largely stemmed from the increasing active sites on the surface of catalysts owing to the decreasing particle size. 相似文献
47.
Dr. Jianwei Nai Zhengbo Chen Haopeng Li Fangyuan Li Yang Bai Prof. Lidong Li Lin Guo 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(2):501-508
As the properties of nanomaterials are strongly dependent on their size, shape and nanostructures, probing the relations between macro‐properties and nanostructures is challenging for nanoscientists. Herein, we deliberately chose three types of Ni(OH)2 with hexagonal, truncated trigonal, and trigonal hourglass‐like nanostructures, respectively, as the electrode modifier to demonstrate the correlation between the nanostructures and their electrocatalytic performance towards L ‐histidine. It was found that the hexagonal hourglass‐like Ni(OH)2 sample had the best electrocatalytic activity, which can be understood by a cooperative mechanism: on one hand, the hexagonal sample possesses the largest specific surface area and the tidiest nanostructure, resulting in the most orderly packing on the electrode surface; on the other hand, its internal structure with the most stacking faults would generate a lot of unstable protons, leading to an enhanced electronic conductivity. The findings are important because they provide a clue for materials design and engineering to meet a specific requirement for electrocatalysis of L ‐histidine, possibly even for other biomolecules. In addition, the hexagonal Ni(OH)2‐based biosensor shows excellent sensitivity and selectivity in the determination of L ‐histidine and offers a promising feature for the analytical application in real biological samples. 相似文献
48.
A mesoporous silica nanoparticle (MSN) based fluorescent sensor for dopamine was constructed with probes inside particle pores and β-cyclodextrin (β-CD) molecules on the particle surface as the selective barricade. The synergistic action of both the hydrophilic rim and hydrophobic cavity of β-CD ensures that the sensor can distinguish dopamine from other biological competitors. 相似文献
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50.
Zhao Fangyuan Wang Fei Zhao Weining Zhou Jing Liu Yang Zou Lina Ye Baoxian 《Mikrochimica acta》2011,173(3-4):383-389
A facile, one-step and template-free method has been developed for the electrodeposition of well-dispersed platinum nanoparticles (Pt-NPs) on a glassy carbon electrode. The effects of various inorganic anions and overpotential on the morphologies and dimensions of the final products were investigated. The resulting Pt-NPs show high electrocatalytic activity towards methanol oxidation and are less easily poisoned by carbon monoxide. Figure
In this study, we have developed a simple, environmentally benign, controllable, and template-free method for the electrodeposition of monodispersed Pt NPs on a glassy carbon electrode. The resulting Pt NPs display high catalytic activity towards methanol oxidation, and are less easily poisoned by carbon monoxide. 相似文献