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991.
Liangshen Duan Qin Nie Yongxin Hu Liming Wang Kaiyan Guo Zhuoyi Zhou Xu Song Yuanhong Tu Hui Liu Thomas Hansen Jian-song Sun Qingju Zhang 《Angewandte Chemie (International ed. in English)》2023,62(33):e202306971
Herein, we described the first synthesis of the pentasaccharide and decasaccharide of the A. baumannii ATCC 17961 O-antigen for developing a synthetic carbohydrate-based vaccine against A. baumannii infection. The efficient synthesis of the rare sugar 2,3-diacetamido-glucuronate was achieved using our recently introduced organocatalytic glycosylation method. We found, for the first time, that long-range levulinoyl group participation via a hydrogen bond can result in a significantly improved β-selectivity in glycosylations. This solves the stereoselectivity problem of highly branched galactose acceptors. The proposed mechanism was supported by control experiments and DFT computations. Benefiting from the long-range levulinoyl group participation strategy, the pentasaccharide donor and acceptor were obtained via an efficient [2+1+2] one-pot glycosylation method and were used for the target decasaccharide synthesis. 相似文献
992.
Xiaoyang Cheng Xiaotian Jiang Shuhu Yin Lifei Ji Yani Yan Guang Li Rui Huang Prof. Chongtai Wang Prof. Honggang Liao Prof. Yanxia Jiang Prof. Shigang Sun 《Angewandte Chemie (International ed. in English)》2023,62(34):e202306166
To achieve the Fe−N−C materials with both high activity and durability in proton exchange membrane fuel cells, the attack of free radicals on Fe−N4 sites must be overcome. Herein, we report a strategy to effectively eliminate radicals at the source to mitigate the degradation by anchoring CeO2 nanoparticles as radicals scavengers adjacent (Scaad-CeO2) to the Fe−N4 sites. Radicals such as ⋅OH and HO2⋅ that form at Fe−N4 sites can be instantaneously eliminated by adjacent CeO2, which shortens the survival time of radicals and the regional space of their damage. As a result, the CeO2 scavengers in Fe−NC/Scaad-CeO2 achieved ∼80 % elimination of the radicals generated at the Fe−N4 sites. A fuel cell prepared with the Fe−NC/Scaad-CeO2 showed a smaller peak power density decay after 30,000 cycles determined with US DOE PGM-relevant AST, increasing the decay of Fe−NCPhen from 69 % to 28 % decay. 相似文献
993.
Shuyan Gong Mingze Sun Yiyang Lee Nigel Becknell Jiangwei Zhang Zhongqi Wang Liang Zhang Zhiqiang Niu 《Angewandte Chemie (International ed. in English)》2023,62(4):e202214516
Single crystal surfaces with highly coordinated sites very often hold high specific activities toward oxygen reduction reaction (ORR) and others. Transposing their high specific activity to practical high-surface-area electrocatalysts remains challenging. Here, ultrathin Pt(100) alloy surface is constructed via epitaxial growth. The surface shows 3.1–6.9 % compressive strain and bulk-like characteristics as demonstrated by site-probe reactions and different spectroscopies. Its ORR activity exceeds that of bulk Pt3Ni(100) and Pt(111) and presents a 19-fold increase in specific activity and a 13-fold increase in mass activity relative to commercial Pt/C. Moreover, the electrochemically active surface area (ECSA) is increased by 4-fold compared to traditional thin films (e.g. NSTF), which makes the catalyst more tolerant to voltage loss at high current densities under fuel cell operation. This work broadens the family of extended surface catalysts and highlights the knowledge-driven approach in the development of advanced electrocatalysts. 相似文献
994.
Xiao-Yu Li Dr. Tao Wang Yu-Chen Cai Zhao-Dong Meng Jing-Wen Nan Dr. Jin-Yu Ye Prof. Dr. Jun Yi Prof. Dr. Dong-Ping Zhan Prof. Dr. Na Tian Prof. Dr. Zhi-You Zhou Prof. Dr. Shi-Gang Sun 《Angewandte Chemie (International ed. in English)》2023,62(14):e202218669
Proton transfer is crucial for electrocatalysis. Accumulating cations at electrochemical interfaces can alter the proton transfer rate and then tune electrocatalytic performance. However, the mechanism for regulating proton transfer remains ambiguous. Here, we quantify the cation effect on proton diffusion in solution by hydrogen evolution on microelectrodes, revealing the rate can be suppressed by more than 10 times. Different from the prevalent opinions that proton transport is slowed down by modified electric field, we found water structure imposes a more evident effect on kinetics. FTIR test and path integral molecular dynamics simulation indicate that proton prefers to wander within the hydration shell of cations rather than to hop rapidly along water wires. Low connectivity of water networks disrupted by cations corrupts the fast-moving path in bulk water. This study highlights the promising way for regulating proton kinetics via a modified water structure. 相似文献
995.
Keming Song Xiang Wang Zhengkun Xie Zhiwei Zhao Zhe Fang Zhengfeng Zhang Jun Luo Pengfei Yan Zhangquan Peng Weihua Chen 《Angewandte Chemie (International ed. in English)》2023,62(10):e202216450
Solid-electrolyte interphase (SEI) seriously affects battery's cycling life, especially for high-capacity anode due to excessive electrolyte decomposition from particle fracture. Herein, we report an ultrathin SEI (3–4 nm) induced by Cu+-tailored double electrical layer (EDL) to suppress electrolyte consumption and enhance cycling stability of CuS anode in sodium-ion batteries. Unique EDL with SO3CF3-Cu complex absorbing on CuS in NaSO3CF3/diglyme electrolyte is demonstrated by in situ surface-enhanced Raman, Cyro-TEM and theoretical calculation, in which SO3CF3-Cu could be reduced to CuF2-rich SEI. Dispersed CuF2 and F-containing compound can provide good interfacial contact for formation of ultrathin and stable SEI film to minimize electrolyte consumption and reduce activation energy of Na+ transport. As a result, the modified CuS delivers high capacity of 402.8 mAh g−1 after 7000 cycles without capacity decay. The insights of SEI construction pave a way for high-stability electrode. 相似文献
996.
Linlong Dai Yuheng Liu Qing Xu Meifang Wang Dr. Qiaohong Zhu Prof. Dr. Peiyuan Yu Prof. Dr. Guofu Zhong Prof. Dr. Xiaofei Zeng 《Angewandte Chemie (International ed. in English)》2023,62(7):e202216534
Diaryl ethers are widespread in biologically active compounds, ligands and catalysts. It is known that the diaryl ether skeleton may exhibit atropisomerism when both aryl rings are unsymmetrically substituted with bulky groups. Despite recent advances, only very few catalytic asymmetric methods have been developed to construct such axially chiral compounds. We describe herein a dynamic kinetic resolution approach to axially chiral diaryl ethers via a Brønsted acid catalyzed atroposelective transfer hydrogenation (ATH) reaction of dicarbaldehydes with anilines. The desired diaryl ethers could be obtained in moderate to good chemical yields (up to 79 %) and high enantioselectivities (up to 95 % ee) under standard reaction conditions. Such structural motifs are interesting precursors for further transformations and may have potential applications in the synthesis of chiral ligands or catalysts. 相似文献
997.
Dr. Yusen Li Xi Su Wenhao Zheng Dr. Jia-Jia Zheng Linshuo Guo Prof. Mischa Bonn Prof. Xingfa Gao Dr. Hai I. Wang Prof. Long Chen 《Angewandte Chemie (International ed. in English)》2023,62(10):e202216795
Targeted synthesis of kagome ( kgm ) topologic 2D covalent organic frameworks remains challenging, presumably due to the severe dependence on building units and synthetic conditions. Herein, two isomeric “two-in-one” monomers with different lengths of substituted arms based on naphthalene core (p-Naph and m-Naph) are elaborately designed and utilized for the defined synthesis of isomeric kgm Naph-COFs. The two isomeric frameworks exhibit splendid crystallinity and showcase the same chemical composition and topologic structure with, however, different pore channels. Interestingly, C60 is able to uniformly be encapsulated into the triangle channels of m-Naph-COF via in situ incorporation method, while not the isomeric p-Naph-COF, likely due to the different pore structures of the two isomeric COFs. The resulting stable C60@m-Naph-COF composite exhibits much higher photoconductivity than the m-Naph-COF owing to charge transfer between the conjugated skeletons and C60 guests. 相似文献
998.
Yibo Wang Pengyu Meng Zhaohui Yang Dr. Min Jiang Dr. Jian Yang Dr. Huanxin Li Prof. Jiao Zhang Prof. Baode Sun Prof. Chaopeng Fu 《Angewandte Chemie (International ed. in English)》2023,62(28):e202304229
Highly-active and low-cost bifunctional electrocatalysts for oxygen reduction and evolution are essential in rechargeable metal-air batteries, and single atom catalysts with Fe−N−C are promising candidates. However, the activity still needs to be boosted, and the origination of spin-related oxygen catalytic performance is still uncertain. Herein, an effective strategy to regulate local spin state of Fe−N−C through manipulating crystal field and magnetic field is proposed. The spin state of atomic Fe can be regulated from low spin to intermediate spin and to high spin. The cavitation of dxz and dyz orbitals of high spin FeIII can optimize the O2 adsorption and promote the rate-determining step (*O2 to *OOH). Benefiting from these merits, the high spin Fe−N−C electrocatalyst displays the highest oxygen electrocatalytic activities. Furthermore, the high spin Fe−N−C-based rechargeable zinc-air battery displays a high power density of 170 mW cm−2 and good stability. 相似文献
999.
Jing Wang Yahui Wang Yan Liang Prof. Dr. Liejin Zhou Dr. Lijuan Liu Prof. Dr. Zuxiao Zhang 《Angewandte Chemie (International ed. in English)》2023,62(5):e202215062
C−F insertion of carbon-atom units is underdeveloped although it poses significant potential applications in both drug discovery and development. Herein, we report a photocatalytic protocol for late-stage modification of trifluoromethyl aromatic drugs involving formal insertion of abundant alkene feedstocks into a benzylic C−F bond selectively. This redox-neutral transformation features mild conditions and extraordinary functional group tolerance. Preliminary studies are consistent with this transformation involving a radical-polar crossover pathway. Additionally, it offers an alternative strategy for difunctionalization of alkenes via quenching of the carbocation intermediate with nucleophiles other than external fluoride. 相似文献
1000.
Yanan Chang Zhangyu Ma Xuyun Lu Shasha Wang Prof. Jianchun Bao Prof. Ying Liu Prof. Chao Ma 《Angewandte Chemie (International ed. in English)》2023,62(41):e202310163
The rational design of advanced nanohybrids (NHs) with optimized interface electronic environment and rapid reaction kinetics is pivotal to electrocatalytic schedule. Herein, we developed a multiple heterogeneous Co9S8/Co3S4/Cu2S nanoparticle in which Co3S4 germinates between Co9S8 and Cu2S. Using high-angle annular-dark-field imaging and theoretical calculation, it was found that the integration of Co9S8 and Cu2S tends to trigger the interface phase transition of Co9S8, leading to Co3S4 interlayer due to the low formation energy of Co3S4/Cu2S (−7.61 eV) than Co9S8/Cu2S (−5.86 eV). Such phase transition not only lowers the energy barrier of oxygen evolution reaction (OER, from 0.335 eV to 0.297 eV), but also increases charge carrier density (from 7.76×1014 to 2.09×1015 cm−3), and creates more active sites. Compared to Co9S8 and Cu2S, the Co9S8/Co3S4/Cu2S NHs also demonstrate notable photothermal effect that can heat the catalyst locally, offset the endothermic enthalpy change of OER, and promote carrier migrate, reaction intermediates adsorption/deprotonation to improve reaction kinetics. Profiting from these favorable factors, the Co9S8/Co3S4/Cu2S catalyst only requires an OER overpotential of 181 mV and overall water splitting cell voltage of 1.43 V to driven 10 mA cm−2 under the irradiation of near-infrared light, outperforming those without light irradiation and many reported Co-based catalysts. 相似文献