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991.
Yufei Shu Dr. Xing Lin Dr. Haiyan Qin Zhuang Hu Prof. Yizheng Jin Prof. Xiaogang Peng 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(50):22496-22507
This article offers a materials-chemistry perspective for colloidal quantum dots (QDs) in the field of display, including QD-enhanced liquid-crystal-display (QD-LCD) and QD-based light-emitting-diodes (QLEDs) display. The rapid successes of QDs for display in the past five years are not accidental but have a deep root in both maturity of their synthetic chemistry and their unique chemical, optical, and optoelectronic properties. This article intends to discuss the natural match of QD emitters for display and chemical means to eventually bring about their full potential. 相似文献
992.
Dr. Jiong Wang Dr. Xiang Huang Dr. Shibo Xi Prof. Dr. Hu Xu Prof. Dr. Xin Wang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(43):19324-19329
Efficient electron communication between molecular catalyst and support is critical for heterogeneous molecular electrocatalysis and yet it is often overlooked during the catalyst design. Taking CO2 electro-reduction on tetraphenylporphyrin cobalt (PCo) immobilized onto graphene as an example, we demonstrate that adding a relay molecule improves the interfacial electron communication. While the directly immobilized PCo on graphene exhibits relatively poor electron communications, it is found that diphenyl sulfide serves as an axial ligand for PCo and it improves the redox activity of PCo on the graphene surface to facilitate the generation of [PCo].- active sites for CO2 reduction. Thus, the turnover frequencies of the immobilized Co complexes are increased. Systematic structural analysis indicates that the benzene rings of diphenyl sulfide exhibit strong face-to-face stacking with graphene, which is proposed as an efficient medium to facilitate the interfacial electron communication. 相似文献
993.
Qi Hu Zhen Han Xiaodeng Wang Guomin Li Ziyu Wang Xiaowan Huang Hengpan Yang Xiangzhong Ren Qianling Zhang Jianhong Liu Prof. Chuanxin He 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(43):19216-19221
Previous density-functional theory (DFT) calculations show that sub-nanometric Cu clusters (i.e., 13 atoms) favorably generate CH4 from the CO2 reduction reaction (CO2RR), but experimental evidence is lacking. Herein, a facile impregnation-calcination route towards Cu clusters, having a diameter of about 1.0 nm with about 10 atoms, was developed by double confinement of carbon defects and micropores. These Cu clusters enable high selectivity for the CO2RR with a maximum Faraday efficiency of 81.7 % for CH4. Calculations and experimental results show that the Cu clusters enhance the adsorption of *H and *CO intermediates, thus promoting generation of CH4 rather than H2 and CO. The strong interactions between the Cu clusters and defective carbon optimize the electronic structure of the Cu clusters for selectivity and stability towards generation of CH4. Provided here is the first experimental evidence that sub-nanometric Cu clusters facilitate the production of CH4 from the CO2RR. 相似文献
994.
Guangjun Li Weigang Hu Yongnan Sun Jiayu Xu Xiao Cai Xinglian Cheng Yuying Zhang Ancheng Tang Xu Liu Prof. Mingyang Chen Prof. Weiping Ding Prof. Yan Zhu 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(47):21321-21328
The emergence of atomically precise metal nanoclusters with unique electronic structures provides access to currently inaccessible catalytic challenges at the single-electron level. We investigate the catalytic behavior of gold Au25(SR)18 nanoclusters by monitoring an incoming and outgoing free valence electron of Au 6s1. Distinct performances are revealed: Au25(SR)18− is generated upon donation of an electron to neutral Au25(SR)180 and this is associated with a loss in reactivity, whereas Au25(SR)18+ is generated from dislodgment of an electron from neutral Au25(SR)180 with a loss in stability. The reactivity diversity of the three Au25(SR)18 clusters stems from different affinities with reactants and the extent of intramolecular charge migration during the reactions, which are closely associated with the valence occupancies of the clusters varied by one electron. The stability difference in the three clusters is attributed to their different equilibria, which are established between the AuSR dissociation and polymerization influenced by one electron. 相似文献
995.
Dr. Zhenhua Gao Baoyuan Xu Tongjin Zhang Zhen Liu Weiguang Zhang Xun Sun Yang Liu Dr. Xue Wang Dr. Zifei Wang Prof. Yongli Yan Prof. Fengqin Hu Prof. Xiangeng Meng Prof. Yong Sheng Zhao 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(43):19222-19226
Micro/nanoscale photonic barcodes based on multicolor luminescent segmented heterojunctions hold potential for applications in information security. However, such multicolor heterojunctions reported thus far are exclusively based on static luminescent signals, thus restricting their application in advanced confidential information protection. Reported here is a strategy to design responsive photonic barcodes with heterobimetallic (Tb3+/Eu3+) metal—organic framework multicolor heterostructures. The spatial colors could be precisely controlled by thermally manipulating the energy-transfer process between the two lanthanides, thus achieving responsive covert photonic barcodes. Also demonstrated is that spatially resolved responsive barcodes with multi-responsive features could be created in a single heterostructure. These findings offer unique opportunities to purposely design highly integrated responsive microstructures and smart devices toward advanced anti-counterfeiting applications. 相似文献
996.
Ruibing An Xiaoyang Cheng Shixuan Wei Yuxuan Hu Yidan Sun Zheng Huang Prof. Hong-Yuan Chen Prof. Deju Ye 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(46):20817-20825
Stimuli-responsive smart photosensitizer (PS) nanoassemblies that allow enhanced delivery and controlled release of PSs are promising for imaging-guided photodynamic therapy (PDT) of tumors. However, the lack of high-sensitivity and spatial-resolution signals and fast washout of released PSs from tumor tissues have impeded PDT efficacy in vivo. Herein, we report tumor targeting, redox-responsive magnetic and fluorogenic PS nanoassemblies ( NP-RGD ) synthesized via self-assembly of a cRGD- and disulfide-containing fluorogenic and paramagnetic small molecule ( 1-RGD ) for fluorescence/magnetic resonance bimodal imaging-guided tumor PDT. NP-RGD show high r1 relaxivity but quenched fluorescence and PDT activity; disulfide reduction by glutathione (GSH) promotes efficient disassembly into a small-molecule probe ( 2-RGD ) and an organic PS (PPa-SH), which could further bind with intracellular albumin, allowing prolonged retention and cascade activation of fluorescence and PDT to ablate tumors. 相似文献
997.
Guifa Zhai Wenyan Wang Dr. Wei Xu Guo Sun Chaoqun Hu Xiangming Wu Zisong Cong Liang Deng Yanrong Shi Prof. Dr. Peter F. Leadlay Prof. Dr. Heng Song Prof. Dr. Kui Hong Prof. Dr. Zixin Deng Prof. Dr. Yuhui Sun 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(50):22926-22930
The colinearity of canonical modular polyketide synthases, which creates a direct link between multienzyme structure and the chemical structure of the biosynthetic end-product, has become a cornerstone of knowledge-based genome mining. Herein, we report genetic and enzymatic evidence for the remarkable role of an enoylreductase in the polyketide synthase for azalomycin F biosynthesis. This internal enoylreductase domain, previously identified as acting only in the second of two chain extension cycles on an initial iterative module, is shown to also catalyze enoylreduction in trans within the next module. The mechanism for this rare deviation from colinearity appears to involve direct cross-modular interaction of the reductase with the longer acyl chain, rather than back transfer of the substrate into the iterative module, suggesting an additional and surprising plasticity in natural PKS assembly-line catalysis. 相似文献
998.
Long Chen Hanrui Zhang Shengnan Liu Chenghua Sun Xiujie Hu Shuyun Zhou 《Surface and interface analysis : SIA》2020,52(7):389-395
Designed growth of zinc oxide (ZnO)/poly(3,4-ethylenedioxythiophene) (PEDOT) core/shell hybrid nanotube arrays has been achieved by electropolymerization technique. The ZnO/PEDOT hybrid nanotubes electropolymerized for 2000-second display enhanced electrochromic properties of the contrast ratio up to 31.3%, a lot higher than those of the pure PEDOT and ZnO/PEDOT hybrid nanorods. Moreover, the coloring efficiency of the hybrid nanotubes increases from 105.2 cm2 C−1 of ZnO/PEDOT hybrid nantotube with the electrodeposition time of 1000 seconds to 122.2 cm2 C−1 of 2000 seconds at 520 nm. Therefore, the hybrid composite nanotubes fabricated by the in situ electrodeposition techniques may demonstrate huge potential applications in energy-saving technologies such as smart windows. 相似文献
999.
Yanzhen Han Liying Xun Xiangji Wang Shuopeng Yang Zhanyong Sun Hongmei Shi Xiangdong Xu Shen Hu 《Electrophoresis》2020,41(16-17):1392-1399
Caffeine (CA) is a common xanthine alkaloid found in tea leaves, coffee beans, and other natural plants, and is the most widely used psychotropic substance in the world. Accumulating evidence suggests that low plasma levels of CA and its metabolites may serve as reliable diagnostic markers for early Parkinson's disease (PD) patients. In this study, we demonstrated a new MEKC method for determining CA and its three main downstream metabolites, paraxanthine (PX), theobromine (TB), and theophylline (TP), in human plasma. Plasma samples were collected, and analyzed using MEKC, after SPE. The running buffer was composed of 35 mM phosphate, pH of 10.5, and 25 mM SDS. The separation voltage was 15 kV and the detection wavelength was at 210 nm. Under the optimum conditions, four distinct analytes were completely separated and detected in less than 12 min. Method limits of detection were as low as 7.5 ng/mL for CA, 5.0 ng/mL for TB, and 4.0 ng/mL for both PX and TP. The recoveries were between 88.0% and 105.9%. This method was successfully applied to 27 human plasma samples. The results indicate that the plasma concentrations of the four analytes are significantly lower in patients with early PD than in control subjects (p < 0.05). The area under curve was improved to 0.839 when CA and its three main metabolites were included, suggesting that MEKC testing of CA, TP, TB, and PX may serve as a potential method for early diagnosis of PD. 相似文献
1000.
Hweiyan Tsai Hsiao-Ching Hu Chih-Chung Hsieh Yi-Hsuan Lu Chien-Hong Chen Chwan-Bor Fuh 《中国化学会会志》2020,67(1):152-159
Chloramphenicol (CAP) is a veterinary antibiotic that has been banned due to its severe side effects in humans. Through the application of manure, veterinary antibiotics can enter the soil, where they can be taken up by crops and vegetables and pose a potential health hazard to humans. Thus, it is highly desirable to develop a rapid and sensitive tool for on-site detection of CAP to ensure food safety and to control the abuse of antibiotics. To this end, nitrogen-doped graphene quantum dots (N-GQDs) were successfully prepared via microwave-assisted synthesis using citric acid and urea as carbon and nitrogen sources, respectively. Analytical results suggested that the interaction between N-GQDs and CAP could occurs via π-π stacking, which quenched N-GQD fluorescence. CAP spiked into chicken feed could be rapidly extracted with ethanol and quantified based on N-GQD fluorescence quenching without further separation. This method showed good recovery (97–102.6%), a low detection limit (1.8 ppm), and was not affected by interference from florfenicol, and thiamphenicol, legal substitute antibiotics. This method has excellent potential for determination of CAP in livestock feed and soil. 相似文献