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排序方式: 共有654条查询结果,搜索用时 15 毫秒
651.
Dr. Dongdong Wang Huili Peng Shaojie Zhang Hongxia Liu Nana Wang Prof. Jian Yang 《Angewandte Chemie (International ed. in English)》2023,62(50):e202315834
Aqueous zinc metal batteries hold great promise for large-scale energy storage because of their high safety, rich material resources and low cost. However, the freeze of aqueous electrolytes hinders low-temperature operation of the batteries. Here, aqueous localized anion-cation aggregated electrolytes composed of Zn(BF4)2 as the salt and tetrahydrofuran (THF) as the diluent, are developed to improve the low-temperature performance of the Zn anode. THF promotes the inclusion of BF4− in the solvation sheath of Zn2+, facilitating the formation of ZnF2-rich solid-electrolyte-interphase. THF also affects the hydrogen bonding between neighboring H2O molecules, effectively lowering the freezing point. Therefore, the full cells of Zn||polyaniline (PANI) exhibit an ultralong cycle life of 8000 cycles with an average Coulombic efficiency of 99.99 % at −40 °C. Impressively, the pouch cells display a high capacity retention of 86.2 % after 500 cycles at −40 °C, which demonstrates the great prospect of such electrolytes in cold regions. This work provides new insights for the design of low-temperature aqueous electrolytes. 相似文献
652.
Dr. Zhonglin Liu Lucas J. Oxtoby Juntao Sun Zi-Qi Li Dr. Nana Kim Dr. Geraint H. M. Davies Prof. Keary M. Engle 《Angewandte Chemie (International ed. in English)》2023,62(4):e202214153
The site-selective palladium-catalyzed three-component coupling of unactivated alkenyl carbonyl compounds, aryl- or alkenylboronic acids, and N-fluorobenzenesulfonimide is described herein. Tuning of the steric environment on the bidentate directing auxiliary enhances regioselectivity and facilitates challenging C(sp3)−F reductive elimination from a PdIV intermediate to afford 1,2-carbofluorination products in moderate to good yields. 相似文献
653.
Xiling Wang Xiaodan Lin Yiping Jiang Xiangquan Qin Nana Ma Fuquan Yao Sheng Dong Chuanfei Liu Yingang Feng Longyi Jin Mo Xian Zhiqi Cong 《Angewandte Chemie (International ed. in English)》2023,62(13):e202217678
Applications of the peroxidase activity of cytochrome P450 enzymes in synthetic chemistry remain largely unexplored. We present herein a protein engineering strategy to increase cytochrome P450BM3 peroxidase activity for the direct nitration of aromatic compounds and terminal aryl-substituted olefins in the presence of a dual-functional small molecule (DFSM). Site-directed mutations of key active-site residues allowed the efficient regulation of steric effects to limit substrate access and, thus, a significant decrease in monooxygenation activity and increase in peroxidase activity. Nitration of several phenol and aniline compounds also yielded ortho- and para-nitration products with moderate-to-high total turnover numbers. Besides direct aromatic nitration by P450 variants using nitrite as a nitrating agent, we also demonstrated the use of the DFSM-facilitated P450 peroxidase system for the nitration of the vinyl group of styrene and its derivatives. 相似文献
654.
In engineering practice, one of the important problems is the problem of finding full-strength contours which permits to control stress concentration at the hole boundary. The article addresses the mixed problem of plane elasticity theory for doubly-connected domain with partially unknown boundary conditions. In the presented work the stress state of the given body and full-strength contours were defined. (© 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献