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2024年12月31日，《科学》（20230203）一周论文导读2023-02-06 10:16·科学网编译 | 冯维维Science,3 FEB 2023, VOLUME 379 ISSUE 6631《科学》2023年2月3日，第379卷6631期化学ChemistryComputer-aided key step generation in alkaloid total synthesis生物碱全合成中计算机辅助关键步骤生成▲ 作者：YINGFU LIN, RUI ZHANG, DI WANG, AND TIM CERNAK▲ 链接：https://www.science.org/doi/10.1126/science.ade8459▲ 摘要：高效的化学合成对于满足未来对药物、材料和农用化学品的需求至关重要。几十年来，对适度复杂分子的逆向合成分析已经实现了自动化。最近，潜在组合路径的数据爆炸对计算机硬件和软件构成了挑战。作者探索了一种计算策略，将计算机辅助合成规划与分子图编辑相结合，以最大限度地减少生产生物碱所需的合成步骤。▲ Abstract：Efficient chemical synthesis is critical to satisfying future demands for medicines, materials, and agrochemicals. Retrosynthetic analysis of modestly complex molecules has been automated over the course of decades, but the combinatorial explosion of route possibilities has challenged computer hardware and software until only recently. Here, we explore a computational strategy that merges computer-aided synthesis planning with molecular graph editing to minimize the number of synthetic steps required to produce alkaloids.Asymmetric counteranion-directed photoredox catalysis不对称反阴离子定向光氧化还原催化▲ 作者：SAYANTANI DAS, CHENDAN ZHU, DERYA DEMIRBAS, ECKHARD BILL, CHANDRA KANTA DE, AND BENJAMIN▲ 链接：https://www.science.org/doi/10.1126/science.ade8190▲ 摘要：光氧化还原催化要利用光诱导的发色团和底物之间的电子转移来促进化学反应性。在底物与发色团不协调的情况下，控制立体选择性可能具有挑战性。作者报道了一种高度立体选择的方法，将阳离子发色团与手性阴离子配对。在发色团还原后，阴离子与活化的底物配对，在这种情况下，氧化苯乙烯衍生物可进行[2+2]环加成，从而有利于两种潜在镜像产物中一种的形成。▲ Abstract：Photoredox catalysis enables distinctive and broadly applicable chemical reactions, but controlling their selectivity has proven to be difficult. The pursuit of enantioselectivity is a particularly daunting challenge, arguably because of the high energy of the activated radical (ion) intermediates, and previous approaches have invariably required pairing of the photoredox catalytic cycle with an additional activation mode for asymmetric induction. A potential solution for photoredox reactions proceeding via radical ions would be catalytic pairing with enantiopure counterions. However, although attempts toward this approach have been described, high selectivity has not yet been accomplished. Here we report a potentially general solution to radical cation–based asymmetric photoredox catalysis. We describe organic salts, featuring confined imidodiphosphorimidate counteranions that catalyze highly enantioselective [2+2]-cross cycloadditions of styrenes.A room temperature rechargeable Li2O-based lithium-air battery enabled by a solid electrolyte由固体电解质驱动的室温可充电锂空气电池▲ 作者：ALIREZA KONDORI, MOHAMMADREZA ESMAEILIRAD, AND MOHAMMAD ASADI▲ 链接：https://www.science.org/doi/10.1126/science.abq1347▲ 摘要：在能量密度方面，锂空气电池有能力与汽油电池竞争。然而，在大多数体系中，反应途径要么涉及一个或两个电子转移，分别导致过氧化锂（Li2O2）或超氧化物锂（LiO2）。作者研究了一种使用陶瓷-聚乙烯氧化物基复合固体电解质的锂-空气电池，发现它可以通过锂氧化物（Li2O）的形成和分解进行四电子氧化还原反应。该复合电解质通过四电子转移过程表现出较高的离子导电性和稳定性。▲ Abstract：Lithium-air batteries have scope to compete with gasoline in terms of energy density. However, in most systems, the reaction pathways either involve one- or two-electron transfer, leading to lithium peroxide (Li2O2) or lithium superoxide (LiO2), respectively. Kondori et al. investigated a lithium-air battery that uses a ceramic-polyethylene oxide–based composite solid electrolyte and found that it can undergo a four-electron redox reaction through lithium oxide (Li2O) formation and decomposition. The composite electrolyte embedded with Li10GeP2S12 nanoparticles shows high ionic conductivity and stability and high cycle stability through a four-electron transfer process.地球物理学GeophysicsSmoke-weather interaction affects extreme wildfires in diverse coastal regions烟-天气相互作用影响不同沿海地区的极端野火▲ 作者：XIN HUANG, KE DING, JINGYI LIU, ZILIN WANG, RONG TANG, LIAN XUE, HAIKUN WANG, QIANG ZHANG, ZHE-MIN TAN, AND AIJUN DING▲ 链接：https://www.science.org/doi/10.1126/science.add9843▲ 摘要：极端野火威胁着人类生命、空气质量和生态系统。作者展示了天气尺度反馈在地中海和美国西海岸和东南亚季风气候体系中对驱动极端火灾的首要作用。他们发现，烟雾气溶胶的辐射效应可以改变近地表风、空气干燥和降雨，从而通过增强火焰排放以及削弱扩散加剧空气污染。野火、烟雾和天气之间错综复杂的相互作用形成了一个正反馈循环，大大增加了空气污染的暴露。▲ Abstract：Extreme wildfires threaten human lives, air quality, and ecosystems. Here, we show the primacy of synoptic-scale feedback in driving extreme fires in Mediterranean and monsoon climate regimes in the West Coast of the United States and Southeastern Asia. We found that radiative effects of smoke aerosols can modify near-surface wind, air dryness, and rainfall and thus worsen air pollution by enhancing fire emissions and weakening dispersion. The intricate interactions among wildfires, smoke, and weather form a positive feedback loop that substantially increases air pollution exposure.The magmatic web beneath Hawai‘i夏威夷地表下的岩浆网▲ 作者：JOHN D. WILDING, WEIQIANG ZHU, ZACHARY E. ROSS, AND JENNIFER M. JACKSON▲ 链接：https://www.science.org/doi/10.1126/science.ade5755▲ 摘要：夏威夷岛是由著名的莫纳克亚火山、莫纳罗亚火山和基拉韦厄火山形成的。目前最活跃的是基拉韦厄火山，但其他火山仍然可能爆发。作者使用超过20万次地震事件，绘制出40公里深处流入这些火山的岩浆的几何形状。岩浆形成了连接基拉韦厄和莫纳罗亚火山的基岩综合体，并且有一些与莫纳克亚火山有关的证据。观测结果表明火山之间有更大的地下联系，为岩浆运输提供了有趣的见解。▲ Abstract：The island of Hawai‘i is shaped by its well-known volcanoes, Mauna Kea, Mauna Loa, and Ki?lauea. Although Ki?lauea is currently by far the most active, the other volcanoes could still erupt as well. Wilding et al. used more than 200,000 seismic events to map out the geometry of the magma feeding into these volcanoes at a 40-kilometer depth (see the Perspective by Flinders). The magma forms a sill complex that connects Ki?lauea and Mauna Loa, and there is some evidence of connection to Mauna Kea. The observations suggest far greater underground connections between the volcanoes and provide an interesting insight into magma transport.物理学PhysicsMedium-density amorphous ice中密度非晶冰▲ 作者：ALEXANDER ROSU-FINSEN, MICHAEL B. DAVIES, ALFRED AMON, HAN WU, ANDREA SELLA, ANGELOS MICHAELIDES, AND CHRISTOPH G. SALZMANN▲ 链接：https://www.science.org/doi/10.1126/science.abq2105▲ 摘要：水冰有许多晶体相，还有一些无定形结构。复杂的结构图对于理解冰的重要性很重要。Rosu-Finsen等人发现了在低温下球磨六方冰形成的中密度非晶冰。其独特的密度和结构有助于将其确定为一种新形式的冰，从而提出了对于这种重要材料的稳定无定形结构的问题。▲ Abstract：Amorphous ices govern a range of cosmological processes and are potentially key materials for explaining the anomalies of liquid water. A substantial density gap between low-density and high-density amorphous ice with liquid water in the middle is a cornerstone of our current understanding of water. However, we show that ball milling “ordinary” ice Ih at low temperature gives a structurally distinct medium-density amorphous ice (MDA) within this density gap. These results raise the possibility that MDA is the true glassy state of liquid water or alternatively a heavily sheared crystalline state. Notably, the compression of MDA at low temperature leads to a sharp increase of its recrystallization enthalpy, highlighting that H2O can be a high-energy geophysical material.
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