《自然》（20240704出版）一周論文導讀

編譯 | 未玖

Nature,  4 July 2024, VOL 631, ISSUE 8019

《自然》2024年7月4日，第631卷，8019期

材料科學Materials Science

Fabrication of red-emitting perovskite LEDs by stabilizing their octahedral structure

穩定八面體結構制備紅色發光鈣鈦礦LED

▲ 作者：Lingmei Kong, Yuqi Sun, Bin Zhao, Kangyu Ji, Jie Feng, Jianchao Dong, et al.

▲ 鏈接：

https://www.nature.com/articles/s41586-024-07531-9

▲ 摘要：

基于金屬鹵化物鈣鈦礦（PeLEDs）的發光二極管（LEDs）具有高色彩質量和易于溶液處理的優點，是全彩和高清顯示器頗有前景的候選者。盡管人們在應用溴化鉛鈣鈦礦的綠色PeLEDs中取得了巨大成功，但使用碘基對應物實現純紅色（620~650 nm）LEDs仍頗具挑戰性，因其受到低本征帶隙的限制。

研究組報道了整個純紅色區域的高效和顏色穩定的PeLEDs，通過將雙端錨定配體分子摻雜至純碘鈣鈦礦中，在638 nm處的峰值外量子效率達到28.7%。他們證明了有機插層陽離子的一個關鍵功能是通過與暴露的鉛離子配位和增強與碘的氫鍵來穩定鉛碘八面體。該分子協同促進光譜調制，促進鈣鈦礦量子阱之間的電荷轉移，并減少電偏壓下的碘遷移。

研究組實現了碘基鈣鈦礦薄膜的連續可調發射波長，并抑制了由于離子鈣鈦礦中鉛碘鍵能隨著帶隙增加而降低導致的能量損失。重要的是，所得器件在初始亮度為100 cd m?2時表現出杰出的光譜穩定性和超過7600 min的半衰期。

▲ Abstract：

Light-emitting diodes (LEDs) based on metal halide perovskites (PeLEDs) with high colour quality and facile solution processing are promising candidates for full-colour and high-definition displays. Despite the great success achieved in green PeLEDs with lead bromide perovskites, it is still challenging to realize pure-red (620–650?nm) LEDs using iodine-based counterparts, as they are constrained by the low intrinsic bandgap. Here we report efficient and colour-stable PeLEDs across the entire pure-red region, with a peak external quantum efficiency reaching 28.7% at 638?nm, enabled by incorporating a double-end anchored ligand molecule into pure-iodine perovskites. We demonstrate that a key function of the organic intercalating cation is to stabilize the lead iodine octahedron through coordination with exposed lead ions and enhanced hydrogen bonding with iodine. The molecule synergistically facilitates spectral modulation, promotes charge transfer between perovskite quantum wells and reduces iodine migration under electrical bias. We realize continuously tunable emission wavelengths for iodine-based perovskite films with suppressed energy loss due to the decrease in bond energy of lead iodine in ionic perovskites as the bandgap increases. Importantly, the resultant devices show outstanding spectral stability and a half-lifetime of more than 7,600?min at an initial luminance of 100?cd?m?2.

化學Chemistry

Expanding chemistry through in vitro and in vivo biocatalysis

通過體外和體內生物催化擴展化學

▲ 作者：Elijah N. Kissman, Max B. Sosa, Douglas C. Millar, Edward J. Koleski, Kershanthen Thevasundaram & Michelle C. Y. Chang

▲ 鏈接：

https://www.nature.com/articles/s41586-024-07506-w

▲ 摘要：

生命系統包含一個巨大的代謝反應網絡，為化學過程提供了豐富的酶和細胞作為潛在生物催化劑。

蛋白質和細胞生物催化劑的特性（即高選擇性、在環境友好條件下控制反應序列和操作的能力）提供了高效生產分子的方法，同時降低了工業化學的成本和環境影響。此外，生物催化提供了產生化學合成可能無法獲得的化學結構和功能的機會。

研究組綜合考慮了酶、生物合成途徑和細胞工程的發展，使其能夠用于催化新的化學和其他方向。

▲ Abstract：

Living systems contain a vast network of metabolic reactions, providing a wealth of enzymes and cells as potential biocatalysts for chemical processes. The properties of protein and cell biocatalysts—high selectivity, the ability to control reaction sequence and operation in environmentally benign conditions—offer approaches to produce molecules at high efficiency while lowering the cost and environmental impact of industrial chemistry. Furthermore, biocatalysis offers the opportunity to generate chemical structures and functions that may be inaccessible to chemical synthesis. Here we consider developments in enzymes, biosynthetic pathways and cellular engineering that enable their use in catalysis for new chemistry and beyond.

Dynamic stereomutation of vinylcyclopropanes with metalloradicals

乙烯基環丙烷與金屬自由基的動態立體變化

▲ 作者：Marvin Mendel, Teresa M. Karl, Jegor Hamm, Sherif J. Kaldas, Theresa Sperger, Bhaskar Mondal, et al.

▲ 鏈接：

https://www.nature.com/articles/s41586-024-07555-1

▲ 摘要：

在化學過程中，對更大可持續性和更低能源使用不斷增長的需求要求采用全新的方法和反應性原理。在這種背景下，非貴金屬中奇數氧化態通過金屬自由基催化產生迥然不同的反應模式而顯著流行，具有尚未開發的潛力。

與公認的反應性范式相反，有機自由基在加入乙烯基環丙烷后，在應變釋放下導致快速開環，這種轉變廣泛用作自由基介導的機械探針（自由基時鐘）。研究組表明，金屬基自由基（即Ni(I)金屬自由基）觸發可逆順式/反式異構化而非開環。異構化在手性反轉下進行且取決于取代模式，在室溫下不到5分鐘內發生，僅需要添加非貴重催化劑。

綜合計算和實驗機制研究支持金屬自由基催化是這種徹底反應性的起源，合理化了觀察到的立體反轉，揭示了該過程的關鍵反應性特征，包括其可逆性。這些發現使得對映純順式/反式混合物通過多個Ni(I)催化輪迭代熱力學富集為單個非對映體，并擴展到二乙烯基環丙烷，這構成了天然產物和全合成中的戰略基序。

反式異構體通常需要在大約200℃的溫度下加熱才能在外消旋作用下觸發熱異構化，以生成順式二乙烯基環丙烷，然后經歷簡單的Cope型重排，但該研究顯示，類似的反熱力學過程在溫和條件下在Ni(I)金屬催化下進行，而不會損失任何立體化學完整性，從而可以溫和且立體化學純地獲得七元環、稠環系統和螺環。

▲ Abstract：

The ever increasing demands for greater sustainability and lower energy usage in chemical processes call for fundamentally new approaches and reactivity principles. In this context, the pronounced prevalence of odd-oxidation states in less precious metals bears untapped potential for fundamentally distinct reactivity modes via metalloradical catalysis. Contrary to the well-established reactivity paradigm that organic free radicals, upon addition to a vinylcyclopropane, lead to rapid ring opening under strain release—a transformation that serves widely as a mechanistic probe (radical clock) for the intermediacy of radicals—we herein show that a metal-based radical, that is, a Ni(I) metalloradical, triggers reversible cis/trans isomerization instead of opening. The isomerization proceeds under chiral inversion and, depending on the substitution pattern, occurs at room temperature in less than 5?min, requiring solely the addition of the non-precious catalyst. Our combined computational and experimental mechanistic studies support metalloradical catalysis as origin of this profound reactivity, rationalize the observed stereoinversion and reveal key reactivity features of the process, including its reversibility. These insights enabled the iterative thermodynamic enrichment of enantiopure cis/trans mixtures towards a single diastereomer through multiple Ni(I) catalysis rounds and also extensions to divinylcyclopropanes, which constitute strategic motifs in natural product- and total syntheses. While the trans-isomer usually requires heating at approximately 200?°C to trigger thermal isomerization under racemization to cis-divinylcyclopropane, which then undergoes facile Cope-type rearrangement, the analogous contra-thermodynamic process is herein shown to proceed under Ni(I) metalloradical catalysis under mild conditions without any loss of stereochemical integrity, enabling a mild and stereochemically pure access to seven-membered rings, fused ring systems and spirocycles.

A deconstruction–reconstruction strategy for pyrimidine diversification

解構-重構策略助力嘧啶多樣化

▲ 作者：Benjamin J. H. Uhlenbruck, Celena M. Josephitis, Louis de Lescure, Robert S. Paton & Andrew McNally

▲ 鏈接：

https://www.nature.com/articles/s41586-024-07474-1

▲ 摘要：

構效關系（SAR）研究是藥物和農用化學品開發的基礎，但只有少數合成策略適用于小分子候選物中經常遇到的氮雜芳烴。

研究組提出了一種替代方法，將含嘧啶的化合物轉化為各種其他氮雜芳烴。將嘧啶轉化為相應的N—芳基嘧啶鎓鹽，可裂解為三碳亞氨基烯胺構建塊，用于各種雜環形成反應。

這種解構—重建序列使初始嘧啶核多樣化，并能夠獲得如唑類的各種雜環。實際上，這種方法實現了在復雜分子上形成雜環，從而生成其他方法難以獲得的類似物。研究組預計這種解構—重建策略將擴展到其他雜環類。

▲ Abstract：

Structure–activity relationship (SAR) studies are fundamental to drug and agrochemical development, yet only a few synthetic strategies apply to the nitrogen heteroaromatics frequently encountered in small molecule candidates. Here we present an alternative approach in which we convert pyrimidine-containing compounds into various other nitrogen heteroaromatics. Transforming pyrimidines into their corresponding N-arylpyrimidinium salts enables cleavage into a three-carbon iminoenamine building block, used for various heterocycle-forming reactions. This deconstruction–reconstruction sequence diversifies the initial pyrimidine core and enables access to various heterocycles, such as azoles. In effect, this approach allows heterocycle formation on complex molecules, resulting in analogues that would be challenging to obtain by other methods. We anticipate that this deconstruction–reconstruction strategy will extend to other heterocycle classes.

地球科學Earth Science

2023 summer warmth unparalleled over the past 2,000 years

2023年夏季為兩千年來最熱

▲ 作者：Jan Esper, Max Torbenson & Ulf Büntgen

▲ 鏈接：

https://www.nature.com/articles/s41586-024-07512-y

▲ 摘要：

包括異常溫暖的北半球夏季在內，2023年被報道為有記錄以來最熱的一年。然而，將最近的人為變暖與過去的自然變率相關聯頗具挑戰性，因為19世紀以來的稀少氣象記錄往往高估了溫度。

研究組將觀測和重建的6~8月地表氣溫結合起來，表明2023年是過去2000年來北半球溫帶最熱的夏季，比自然氣候變率的95%置信區間高出0.5℃以上。2023年6~8月升溫與公元536年重建最冷夏季的對比顯示，前人類世至2023年的最大溫差為3.93℃。

盡管2023年與溫室氣體引起的變暖趨勢一致，且正在進行的厄爾尼諾事件加劇了這一趨勢，但該極端事件強調了實施國際碳減排協議的緊迫性。

▲ Abstract：

Including an exceptionally warm Northern Hemisphere summer, 2023 has been reported as the hottest year on record. However, contextualizing recent anthropogenic warming against past natural variability is challenging because the sparse meteorological records from the nineteenth century tend to overestimate temperatures. Here we combine observed and reconstructed June–August surface air temperatures to show that 2023 was the warmest Northern Hemisphere extra-tropical summer over the past 2,000 years exceeding the 95% confidence range of natural climate variability by more than 0.5 °C. Comparison of the 2023 June–August warming against the coldest reconstructed summer in CE 536 shows a maximum range of pre-Anthropocene-to-2023 temperatures of 3.93?°C. Although 2023 is consistent with a greenhouse-gases-induced warming trend that is amplified by an unfolding El Ni?o event, this extreme emphasizes the urgency to implement international agreements for carbon emission reduction.

Global variability in atmospheric new particle formation mechanisms

大氣新粒子形成機制的全球變率

▲ 作者：Bin Zhao, Neil M. Donahue, Kai Zhang, Lizhuo Mao, Manish Shrivastava, Po-Lun Ma, et al.

▲ 鏈接：

https://www.nature.com/articles/s41586-024-07547-1

▲ 摘要：

氣溶膠污染研究和氣候變化評估的一個關鍵挑戰是了解大氣氣溶膠顆粒最初如何形成。雖然新粒子形成（NPF）機制已在特定地點描述過，但在大多數地區，由于大氣模型模擬關鍵NPF過程的能力有限，該機制在很大程度上仍不確定。

研究組綜合了分子水平的實驗，在一個完全耦合的全球氣候模型中建立了11類NPF機制和前驅體氣體復雜化學轉化的綜合表征。綜合模擬和觀測結果表明，主要的NPF機制在全球范圍內是不同的，并且隨區域和高程而變化。

在大多數氣溶膠濃度高或氣溶膠輻射強迫大的地區，以前被忽視或代表性不足的涉及有機物、胺、碘氧酸和HNO3的機制可能主導著NPF；這些區域包括海洋和人為污染的大陸邊界層，以及熱帶雨林和亞洲季風區上空的對流層上層。這些代表性不足的機制在其他區域也發揮著顯著作用，例如太平洋和大西洋對流層上層。

因此，NPF在對流層下層不同區域以0.5%過飽和度形成云的核中占不同比例（10~80%）。對全球NPF機制的綜合模擬有助于改進氣溶膠氣候效應的估計和源歸因。

▲ Abstract：

A key challenge in aerosol pollution studies and climate change assessment is to understand how atmospheric aerosol particles are initially formed. Although new particle formation (NPF) mechanisms have been described at specific sites, in most regions, such mechanisms remain uncertain to a large extent because of the limited ability of atmospheric models to simulate critical NPF processes. Here we synthesize molecular-level experiments to develop comprehensive representations of 11 NPF mechanisms and the complex chemical transformation of precursor gases in a fully coupled global climate model. Combined simulations and observations show that the dominant NPF mechanisms are distinct worldwide and vary with region and altitude. Previously neglected or underrepresented mechanisms involving organics, amines, iodine oxoacids and HNO3 probably dominate NPF in most regions with high concentrations of aerosols or large aerosol radiative forcing; such regions include oceanic and human-polluted continental boundary layers, as well as the upper troposphere over rainforests and Asian monsoon regions. These underrepresented mechanisms also play notable roles in other areas, such as the upper troposphere of the Pacific and Atlantic oceans. Accordingly, NPF accounts for different fractions (10–80%) of the nuclei on which cloud forms at 0.5% supersaturation over various regions in the lower troposphere. The comprehensive simulation of global NPF mechanisms can help improve estimation and source attribution of the climate effects of aerosols.