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991.
Wang Wang Prof. M. Kevin Brown 《Angewandte Chemie (International ed. in English)》2023,62(32):e202305622
The synthesis of polycyclic compounds is of high interest due to the prevalence of these motifs in drugs and natural products. Herein, we report on the stereoselective construction of 3D bicyclic scaffolds and azetidine derivatives by modulation of N-sulfonylimines to achieve either [4+2]- or [2+2]-cycloaddition reactions. The utility of the method was established by further modulation of the product. Mechanistic studies are also included, which support reaction via Dexter energy transfer. 相似文献
992.
Xingxing Zhang Qingmei Su Gaohui Du Bingshe Xu Shun Wang Zhuo Chen Liming Wang Wenhuan Huang Huan Pang 《Angewandte Chemie (International ed. in English)》2023,62(39):e202304947
Pursuing high power density lithium metal battery with high safety is essential for developing next-generation energy-storage devices, but uncontrollable electrolyte degradation and the consequence formed unstable solid-electrolyte interface (SEI) make the task really challenging. Herein, an ionic liquid (IL) confined MOF/Polymer 3D-porous membrane was constructed for boosting in situ electrochemical transformations of Janus-heterarchical LiF/Li3N-rich SEI films on the nanofibers. Such a 3D-Janus SEI-incorporated into the separator offers fast Li+ transport routes, showing superior room-temperature ionic conductivity of 8.17×10−4 S cm−1 and Li+ transfer number of 0.82. The cryo-TEM was employed to visually monitor the in situ formed LiF and Li3N nanocrystals in SEI and the deposition of Li dendrites, which is greatly benefit to the theoretical simulation and kinetic analysis of the structural evolution during the battery charge and discharge process. In particular, this membrane with high thermal stability and mechanical strength used in solid-state Li||LiFePO4 and Li||NCM-811 full cells and even in pouch cells showed enhanced rate-performance and ultra-long life spans. 相似文献
993.
Jin Xu Prof. Jun Liu Prof. Lixiang Wang 《Angewandte Chemie (International ed. in English)》2023,62(24):e202303870
Since the breakthrough of conductive polymers in 1977, scientists have made great efforts to create small band gap (Eg) conjugated polymers. Two general strategies to design small Eg conjugated polymers are quinoid structure and donor-acceptor structure. Ultrasmall Eg conjugated polymers (Eg<1.0 eV) always suffer from poor air stability because of high-lying HOMO energy levels. In this work, we report a new strategy to design ultrasmall Eg conjugated polymers by N−B←N unit, i.e. balanced resonant boron-nitrogen covalent bond (B−N) and boron-nitrogen coordination bond (B←N). The resulting polymer exhibits an Eg of 0.82 eV and an onset absorption wavelength of >1500 nm. Moreover, the polymer exhibits excellent air stability because of its low-lying LUMO/HOMO energy levels. An unprecedented property of this polymer is the selective light absorption in the infrared range (800–1500 nm) and high transparency in the visible range (400–780 nm). Using this property, for the first time, we demonstrate the application of conjugated polymers as transparent thermal-shielding coating layer on glass, which reduces indoor solar irradiation through window and consequently reduces power consumption for cooling of buildings and cars in summer. 相似文献
994.
Dr. Huanhuan Shi Prof. Mengmeng Li Shuai Fu Dr. Christof Neumann Dr. Xiaodong Li Dr. Wenhui Niu Yunji Lee Prof. Mischa Bonn Dr. Hai I. Wang Prof. Andrey Turchanin Dr. Ali Shaygan Nia Dr. Sheng Yang Prof. Xinliang Feng 《Angewandte Chemie (International ed. in English)》2023,62(28):e202303929
Two-dimensional van der Waals heterostructures (2D vdWHs) have recently gained widespread attention because of their abundant and exotic properties, which open up many new possibilities for next-generation nanoelectronics. However, practical applications remain challenging due to the lack of high-throughput techniques for fabricating high-quality vdWHs. Here, we demonstrate a general electrochemical strategy to prepare solution-processable high-quality vdWHs, in which electrostatic forces drive the stacking of electrochemically exfoliated individual assemblies with intact structures and clean interfaces into vdWHs with strong interlayer interactions. Thanks to the excellent combination of strong light absorption, interfacial charge transfer, and decent charge transport properties in individual layers, thin-film photodetectors based on graphene/In2Se3 vdWHs exhibit great promise for near-infrared (NIR) photodetection, owing to a high responsivity (267 mA W−1), fast rise (72 ms) and decay (426 ms) times under NIR illumination. This approach enables various hybrid systems, including graphene/In2Se3, graphene/MoS2 and graphene/MoSe2 vdWHs, providing a broad avenue for exploring emerging electronic, photonic, and exotic quantum phenomena. 相似文献
995.
Min Wang Huimin Chen Min Wang Jinxiu Wang Dr. Yongxiao Tuo Prof. Wenzhen Li Shanshan Zhou Linghui Kong Prof. Guangbo Liu Prof. Luhua Jiang Guoxiong Wang 《Angewandte Chemie (International ed. in English)》2023,62(40):e202306456
Heterostructured oxides with versatile active sites, as a class of efficient catalysts for CO2 electrochemical reduction (CO2ER), are prone to undergo structure reconstruction under working conditions, thus bringing challenges to understanding the reaction mechanism and rationally designing catalysts. Herein, we for the first time elucidate the structural reconstruction of CuO/SnO2 under electrochemical potentials and reveal the intrinsic relationship between CO2ER product selectivity and the in situ evolved heterostructures. At −0.85 VRHE, the CuO/SnO2 evolves to Cu2O/SnO2 with high selectivity to HCOOH (Faradaic efficiency of 54.81 %). Mostly interestingly, it is reconstructed to Cu/SnO2-x at −1.05 VRHE with significantly improved Faradaic efficiency to ethanol of 39.8 %. In situ Raman spectra and density functional theory (DFT) calculations reveal that the synergetic absorption of *COOH and *CHOCO intermediates at the interface of Cu/SnO2-x favors the formation of *CO and decreases the energy barrier of C−C coupling, leading to high selectivity to ethanol. 相似文献
996.
997.
Dr. Qing-Yun Guo Zitong Wang Dr. Xuanyu Feng Yingjie Fan Prof. Dr. Wenbin Lin 《Angewandte Chemie (International ed. in English)》2023,62(35):e202306905
Although many monometallic active sites have been installed in metal–organic frameworks (MOFs) for catalytic reactions, there are no effective strategies to generate bimetallic catalysts in MOFs. Here we report the synthesis of a robust, efficient, and reusable MOF catalyst, MOF-NiH, by adaptively generating and stabilizing dinickel active sites using the bipyridine groups in MOF-253 with the formula of Al(OH)(2,2′-bipyridine-5,5′-dicarboxylate) for Z-selective semihydrogenation of alkynes and selective hydrogenation of C=C bonds in α,β-unsaturated aldehydes and ketones. Spectroscopic studies established the dinickel complex (bpy⋅−)NiII(μ2-H)2NiII(bpy⋅−) as the active catalyst. MOF-NiH efficiently catalyzed selective hydrogenation reactions with turnover numbers of up to 192 and could be used in five cycles of hydrogenation reactions without catalyst leaching or significant decrease of catalytic activities. The present work uncovers a synthetic strategy toward solution-inaccessible Earth-abundant bimetallic MOF catalysts for sustainable catalysis. 相似文献
998.
Dr. Wei-Hua Deng Prof. Qiao-Hong Li Jie Chen Chuan-Zhe Wang Dr. Zhi-Hua Fu Dr. Xiao-Liang Ye Prof. Guan-E Wang Prof. Gang Xu 《Angewandte Chemie (International ed. in English)》2023,62(31):e202305977
The electronic conductivity (EC) of metal–organic frameworks (MOFs) is sensitive to strongly oxidizing guest molecules. Water is a relatively mild species, however, the effect of H2O on the EC of MOFs is rarely reported. We explored the effect of H2O on the EC in the MOFs (NH2)2-MIL-125 and its derivatives with experimental and theoretical investigations. Unexpectedly, a large EC increase of 107 on H2SO4@(NH2)2-MIL-125 by H2O was observed. Brønsted acid–base pairs formed with the −NH2 groups, and H2SO4 played an important role in promoting the charge transfer from H2O to the MOF. Based on H2SO4@(NH2)2-MIL-125, a high-performance chemiresistive humidity sensor was developed with the highest sensitivity, broadest detection range, and lowest limit of detection amongst all reported sensing materials to date. This work not only demonstrated that H2O can remarkably influence the EC of MOFs, but it also revealed that post-modification of the structure of MOFs could enhance the influence of the guest molecule on their EC to design high-performance sensing materials. 相似文献
999.
Catalytic Diastereo- and Enantioselective Cyclopropanation of gem-Dihaloalkanes and Terminal Olefins
Hou-Lu Liu Xinyu Wang Ke Gao Zhaobin Wang 《Angewandte Chemie (International ed. in English)》2023,62(28):e202305987
Chiral cyclopropane derivatives are essential in synthetic chemistry and drug discovery. Their synthesis commonly relies on asymmetric cyclopropanation of diazo compounds, potentially explosive and needing stabilizing substituents. Thus, asymmetric catalytic transformations of non-stabilized carbenes or carbenoids remain a formidable challenge. Herein, we report the unprecedented chromium-catalyzed asymmetric cyclopropanation of readily available gem-dihaloalkanes and terminal olefins. Distinct from previous approaches, gem-dihaloalkanes serve as suitable precursors for non-stabilized carbenes or carbenoids, furnishing various functionalized chiral cyclopropanes. Mechanistic studies, including radical trapping, non-linear effect, and UV/Vis spectroscopy, provide insights into the catalytic process, featuring radical-polar crossover. 相似文献
1000.
Jimin Song Dr. Xiaojuan Yu Dr. Alexei Nefedov Dr. Peter G. Weidler Dr. Sylvian Grosjean Prof. Dr. Stefan Bräse Dr. Yuemin Wang Prof. Dr. Christof Wöll 《Angewandte Chemie (International ed. in English)》2023,62(34):e202306155
Studies on reactions in solutions are often hampered by solvent effects. In addition, detailed investigation on kinetics is limited to the small temperature regime where the solvent is liquid. Here, we report the in situ spectroscopic observation of UV-induced photochemical reactions of aryl azides within a crystalline matrix in vacuum. The matrices are formed by attaching the reactive moieties to ditopic linkers, which are then assembled to yield metal–organic frameworks (MOFs) and surface-mounted MOFs (SURMOFs). These porous, crystalline frameworks are then used as model systems to study azide-related chemical processes under ultrahigh vacuum (UHV) conditions, where solvent effects can be safely excluded and in a large temperature regime. Infrared reflection absorption spectroscopy (IRRAS) allowed us to monitor the photoreaction of azide in SURMOFs precisely. The in situ IRRAS data, in conjunction with XRD, MS, and XPS, reveal that illumination with UV light first leads to forming a nitrene intermediate. In the second step, an intramolecular rearrangement occurs, yielding an indoloindole derivative. These findings unveil a novel pathway for precisely studying azide-related chemical transformations. Reference experiments carried out for solvent-loaded SURMOFs reveal a huge diversity of other reaction schemes, thus highlighting the need for model systems studied under UHV conditions. 相似文献