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991.
Hyperbranched Hybridization Chain Reaction for Triggered Signal Amplification and Concatenated Logic Circuits
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Dr. Sai Bi Min Chen Xiaoqiang Jia Ying Dong Prof. Dr. Zonghua Wang 《Angewandte Chemie (International ed. in English)》2015,54(28):8144-8148
A hyper‐branched hybridization chain reaction (HB‐HCR) is presented herein, which consists of only six species that can metastably coexist until the introduction of an initiator DNA to trigger a cascade of hybridization events, leading to the self‐sustained assembly of hyper‐branched and nicked double‐stranded DNA structures. The system can readily achieve ultrasensitive detection of target DNA. Moreover, the HB‐HCR principle is successfully applied to construct three‐input concatenated logic circuits with excellent specificity and extended to design a security‐mimicking keypad lock system. Significantly, the HB‐HCR‐based keypad lock can alarm immediately if the “password” is incorrect. Overall, the proposed HB‐HCR with high amplification efficiency is simple, homogeneous, fast, robust, and low‐cost, and holds great promise in the development of biosensing, in the programmable assembly of DNA architectures, and in molecular logic operations. 相似文献
992.
Aryne‐Induced Novel Tandem 1,2‐Addition/(3+2) Cycloaddition to Generate Imidazolidines and Pyrrolidines
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Dr. Sharada P. Swain Yi‐Chun Shih Dr. Shwu‐Chen Tsay Joby Jacob Dr. Chun‐Cheng Lin Dr. Kuo Chu Hwang Dr. Jia‐Cherng Horng Prof. Dr. Jih Ru Hwu 《Angewandte Chemie (International ed. in English)》2015,54(34):9926-9930
A new “single‐flask” method was developed for the synthesis of imidazolidines and pyrrolidines with high stereoselectivity. First, a Schiff base was arylated with an aryne. Second, an intramolecular proton transfer took place from the methylene position to the anionic aryne ring. Third, the resultant ylide reacted with a second equivalent of the same Schiff base in situ or an electron‐deficient alkene through a (3+2) cycloaddition. These sequential tandem 1,2‐addition/(3+2) cycloaddition reactions led to the desired heterocycles in 63–88 % yields. 相似文献
993.
Clicked Isoreticular Metal–Organic Frameworks and Their High Performance in the Selective Capture and Separation of Large Organic Molecules
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Chung Yen Ang Hongzhong Chen Dr. Jia Liu Prof. Dr. Ruqiang Zou Prof. Dr. Yanli Zhao 《Angewandte Chemie (International ed. in English)》2015,54(43):12748-12752
Three highly porous metal–organic frameworks (MOFs) with a uniform rht‐type topological network but hierarchical pores were successfully constructed by the assembly of triazole‐containing dendritic hexacarboxylate ligands with ZnII ions. These transparent MOF crystals present gradually increasing pore sizes upon extension of the length of the organic backbone, as clearly identified by structural analysis and gas‐adsorption experiments. The inherent accessibility of the pores to large molecules endows these materials with unique properties for the uptake of large guest molecules. The visible selective adsorption of dye molecules makes these MOFs highly promising porous materials for pore‐size‐dependent large‐molecule capture and separation. 相似文献
994.
Photocatalytically Renewable Micro‐electrochemical Sensor for Real‐Time Monitoring of Cells
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Jia‐Quan Xu Yan‐Ling Liu Qian Wang Huan‐Huan Duo Xin‐Wei Zhang Dr. Yu‐Tao Li Prof. Wei‐Hua Huang 《Angewandte Chemie (International ed. in English)》2015,54(48):14402-14406
Electrode fouling and passivation is a substantial and inevitable limitation in electrochemical biosensing, and it is a great challenge to efficiently remove the contaminant without changing the surface structure and electrochemical performance. Herein, we propose a versatile and efficient strategy based on photocatalytic cleaning to construct renewable electrochemical sensors for cell analysis. This kind of sensor was fabricated by controllable assembly of reduced graphene oxide (RGO) and TiO2 to form a sandwiching RGO@TiO2 structure, followed by deposition of Au nanoparticles (NPs) onto the RGO shell. The Au NPs‐RGO composite shell provides high electrochemical performance. Meanwhile, the encapsulated TiO2 ensures an excellent photocatalytic cleaning property. Application of this renewable microsensor for detection of nitric oxide (NO) release from cells demonstrates the great potential of this strategy in electrode regeneration and biosensing. 相似文献
995.
Feng‐Yang Bai Xiao‐Le Zhu Zi‐Man Jia Xu Wang Yan‐Qiu Sun Prof. Rong‐Shun Wang Prof. Xiu‐Mei Pan 《Chemphyschem》2015,16(8):1768-1776
The mechanism and kinetics of the reactions of CF3COOCH2CH3, CF2HCOOCH3, and CF3COOCH3 with Cl and OH radicals are studied using the B3LYP, MP2, BHandHLYP, and M06‐2X methods with the 6‐311G(d,p) basis set. The study is further refined by using the CCSD(T) and QCISD(T)/6‐311++G(d,p) methods. Seven hydrogen‐abstraction channels are found. All the rate constants, computed by a dual‐level direct method with a small‐curvature tunneling correction, are in good agreement with the experimental data. The tunneling effect is found to be important for the calculated rate constants in the low‐temperature range. For the reaction of CF3COOCH2CH3+Cl, H‐abstraction from the CH2 group is found to be the dominant reaction channel. The standard enthalpies of formation for the species are also calculated. The Arrhenius expressions are fitted within 200–1000 K as kT(1)=8.4×10?20T 2.63exp(381.28/T), kT(2)=2.95×10?21T 3.13exp(?103.21/T), kT(3)=1.25×10?23T 3.37exp(791.98/T), and kT(4)=4.53×10?22T 3.07exp(465.00/T). 相似文献
996.
Direct Determination of Trace Dopamine in an Ascorbic Acid Solution at a Bare Glassy Carbon Electrode Using Differential Pulse Voltammetry
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Lijian Sun Jing Chen Fangmin Zhao Na Liu Yingqiu Zhang Jianbo Jia Jianguo Wang 《Electroanalysis》2015,27(6):1411-1415
It is difficult to monitor dopamine (DA) accurately with a bare glassy carbon electrode because of the interference of ascorbic acid (AA). In this paper, a method for the determination of DA in an AA solution using differential pulse voltammetry was established. Because AA loses its electrochemical activity after being oxidized, hydrogen peroxide was used to oxidize AA, and the interference of AA was completely eliminated. As a result, trace DA could be directly determined in the AA solution with a bare glassy carbon electrode. When trace DA was determined in a 1.0 mmol L?1 AA solution, there was a wide linear range from 3.0×10?8 mol L?1 to 1.0×10?5 mol L?1. The application of this method was demonstrated by the selective measurement of DA in an injection without pretreatment. 相似文献
997.
Reversing the Stereoselectivity of a Palladium‐Catalyzed O‐Glycosylation through an Inner‐Sphere or Outer‐Sphere Pathway
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Shaohua Xiang Kim Le Mai Hoang Jingxi He Yu Jia Tan Prof. Dr. Xue‐Wei Liu 《Angewandte Chemie (International ed. in English)》2015,54(2):604-607
An efficient and concise method for the construction of various O‐glycosidic bonds by a palladium‐catalyzed reaction with a 3‐O‐picoloyl glucal has been developed. The stereochemistry of the anomeric center derives from either an inner‐sphere or outer‐sphere pathway. Harder nucleophiles, such as aliphatic alcohols and sodium phenoxides give β‐products, and α products result from using softer nucleophiles, such as phenol. 相似文献
998.
Formation of DNA:RNA Hybrid G‐Quadruplex in Bacterial Cells and Its Dominance over the Intramolecular DNA G‐Quadruplex in Mediating Transcription Termination
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999.
Hypervalent Iodine Reagents Enable Chemoselective Deboronative/Decarboxylative Alkenylation by Photoredox Catalysis
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Hanchu Huang Kunfang Jia Prof. Dr. Yiyun Chen 《Angewandte Chemie (International ed. in English)》2015,54(6):1881-1884
Chemoselective C(sp3)? C(sp2) coupling reactions under mild reaction conditions are useful for synthesizing alkyl‐substituted alkenes having sensitive functional groups. Reported here is a visible‐light‐induced chemoselective alkenylation through a deboronation/decarboxylation sequence under neutral aqueous reaction conditions at room temperature. This reaction represents the first hypervalent‐iodine‐enabled radical decarboxylative alkenylation reaction, and a novel benziodoxole‐vinyl carboxylic acid reaction intermediate was isolated. This C(sp3)? C(sp2) coupling reaction leads to aryl‐and acyl‐substituted alkenes containing various sensitive functional groups. The excellent chemoselectivity, stable reactants, and neutral aqueous reaction conditions of the reaction suggest future biomolecule applications. 相似文献
1000.
Redox‐Neutral α‐Allylation of Amines by Combining Palladium Catalysis and Visible‐Light Photoredox Catalysis
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Jun Xuan Ting‐Ting Zeng Zhu‐Jia Feng Qiao‐Hui Deng Prof. Dr. Jia‐Rong Chen Dr. Liang‐Qiu Lu Prof. Dr. Wen‐Jing Xiao Prof. Dr. Howard Alper 《Angewandte Chemie (International ed. in English)》2015,54(5):1625-1628
An unprecedented α‐allylation of amines was achieved by combining palladium catalysis and visible‐light photoredox catalysis. In this dual catalysis process, the catalytic generation of allyl radical from the corresponding π‐allylpalladium intermediate was achieved without additional metal reducing reagents (redox‐neutral). Various allylation products of amines were obtained in high yields through radical cross‐coupling under mild reaction conditions. Moreover, the transformation was applied to the formal synthesis of 8‐oxoprotoberberine derivatives which show potential anticancer properties. 相似文献