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《科學》（20230804出版）一周論文導讀
原文地址：http://news.sciencenet.cn/htmlnews/2023/8/506126.shtm
編譯 | 未玖
Science, 4 AUG 2023, VOL 381, ISSUE 6657
《科學》2023年8月4日，第381卷，6657期
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材料科學Materials Science
Intrinsically elastic polymer ferroelectric by precise slight cross-linking
通過精確微交聯實現本征彈性鐵電聚合物
▲ 作者：Liang Gao, Ben-Lin Hu, Linping Wang, Jinwei Cao, Ri He, Fengyuan Zhang, et al.
▲ 鏈接：
https://www.science.org/doi/full/10.1126/science.adh2509
▲ 摘要：
鐵電體是現代世界不可分割的組成部分，在電學、電子學和生物醫學中具有重要意義。然而，鐵電體在新興可穿戴電子產品中的應用受到非彈性變形的限制。
研究組通過塑性鐵電聚合物的微交聯，將鐵電響應和彈性回彈結合到一種材料中，開發了本征彈性鐵電體。精確的微交聯可實現結晶性和回彈性之間的復雜平衡。
因此，研究組制備了在高達70%應變的機械變形下仍具有穩定鐵電響應的彈性鐵電體。這種彈性鐵電體有望應用于可穿戴電子產品，例如彈性鐵電傳感器、信息存儲和能量轉換。
▲ Abstract：
Ferroelectrics are an integral component of the modern world and are of importance in electrics, electronics, and biomedicine. However, their usage in emerging wearable electronics is limited by inelastic deformation. We developed intrinsically elastic ferroelectrics by combining ferroelectric response and elastic resilience into one material by slight cross-linking of plastic ferroelectric polymers. The precise slight cross-linking can realize the complex balance between crystallinity and resilience. Thus, we obtained an elastic ferroelectric with a stable ferroelectric response under mechanical deformation up to 70% strain. This elastic ferroelectric exerts potentials in applications related to wearable electronics, such as elastic ferroelectric sensors, information storage, and energy transduction.
A stable rhombohedral phase in ferroelectric Hf(Zr)1+xO2capacitor with ultralow coercive field
具有超低矯頑場鐵電Hf(Zr)1+xO2電容器中的穩定菱形相
▲ 作者：Yuan Wang, Lei Tao, Roger Guzman, Qing Luo, Wu Zhou, Yang Yang, et al.
▲ 鏈接：
https://www.science.org/doi/full/10.1126/science.adf6137
▲ 摘要：
基于氧化鉿的鐵電材料因其能夠集成到硅電子器件中，是下一代納米級器件頗有潛力的候選者。然而，螢石結構氧化物鐵電器件固有的高矯頑場導致其工作電壓不兼容，耐久性能受限。
研究組發現了一種富含鉿-鋯[Hf(Zr)]的互補金屬氧化物半導體（CMOS）兼容菱形鐵電體Hf(Zr)1+xO2材料。X射線衍射結合掃描透射電鏡顯示，過量的Hf(Zr)原子嵌入在空心位點內，嵌入的原子擴展了晶格，增加了面內和面外應力，從而穩定了菱形相（r相）及其鐵電性質。
該鐵電器件基于r相Hf(Zr)1+xO2，具有超低的矯頑場（約0.65兆伏/厘米），此外還在飽和極化下實現了超過1012次循環的高耐久性。該材料的發現或有助于實現低成本和長壽命的存儲芯片。
▲ Abstract：
Hafnium oxide–based ferroelectric materials are promising candidates for next-generation nanoscale devices because of their ability to integrate into silicon electronics. However, the intrinsic high coercive field of the fluorite-structure oxide ferroelectric devices leads to incompatible operating voltage and limited endurance performance. We discovered a complementary metal-oxide semiconductor (CMOS)–compatible rhombohedral ferroelectric Hf(Zr)1+xO2material rich in hafnium-zirconium [Hf(Zr)]. X-ray diffraction combined with scanning transmission electron microscopy reveals that the excess Hf(Zr) atoms intercalate within the hollow sites. We found that the intercalated atoms expand the lattice and increase the in-plane and out-of-plane stresses, which stabilize both the rhombohedral phase (r-phase) and its ferroelectric properties. Our ferroelectric devices, which are based on the r-phase Hf(Zr)1+xO2, exhibit an ultralow coercive field (~0.65 megavolts per centimeter). Moreover, we achieved a high endurance of more than 1012cycles at saturation polarization. This material discovery may help to realize low-cost and long-life memory chips.
化學Chemistry
Mechanistic snapshots of rhodium-catalyzed acylnitrene transfer reactions
銠催化酰氮烯轉移反應的機理瞬拍
▲ 作者：Hoimin Jung, Jeonguk Kweon, Jong-Min Suh, Mi Hee Lim, Dongwook Kim & Sukbok Chang
▲ 鏈接：
https://www.science.org/doi/full/10.1126/science.adh8753
▲ 摘要：
銠（Rh）酰氮烯配合物廣泛涉及催化C-H酰胺化反應，但尚未能進行分離和結構表征。
為了克服這一挑戰，研究組設計了一種帶有雙齒二惡唑酮配體的發色八面體Rh配合物，其中光誘導金屬到配體的電荷轉移引發催化C-H酰胺化。對Rh-二惡唑酮配合物的X射線光晶體學分析闡明了目標Rh-酰氮賓結構，并提供了單線態氮賓物種主導酰氨基轉移反應的有力證據。
研究組還監測了親核試劑與原位生成的Rh-酰氮賓的結晶反應，為捕獲氮賓轉移的機理瞬拍提供了一個晶體學上可追蹤的反應體系。
▲ Abstract：
Rhodium (Rh) acylnitrene complexes are widely implicated in catalytic C–H amidation reactions but have eluded isolation and structural characterization. To overcome this challenge, we designed a chromophoric octahedral Rh complex with a bidentate dioxazolone ligand, in which photoinduced metal-to-ligand charge transfer initiates catalytic C–H amidation. X-ray photocrystallographic analysis of the Rh-dioxazolone complex allowed structural elucidation of the targeted Rh-acylnitrenoid and provided firm evidence that the singlet nitrenoid species is primarily responsible for acylamino transfer reactions. We also monitored in crystallo reaction of a nucleophile with the in situ–generated Rh-acylnitrenoid, which provided a crystallographically traceable reaction system to capture mechanistic snapshots of nitrenoid transfer.
Photosensitized O2 enables intermolecular alkene cyclopropanation by active methylene compounds
光敏O2通過活性亞甲基化合物實現分子間烯烴環丙烷化
▲ 作者：Dhruba P. Poudel, Amrit Pokhrel, Raj Kumar Tak, Majji Shankar & Ramesh Giri
▲ 鏈接：
https://www.science.org/doi/full/10.1126/science.adg3209
▲ 摘要：
環丙烷是許多臨床前、臨床和商業藥物以及天然產品的關鍵特征。最多產的合成技術是烯烴與重氮烷烴的金屬催化反應，重氮烷是一種高能試劑，需要嚴格的安全預防措施。發現可替代的無害試劑仍是一項持續挑戰。
研究組報道了一種簡單、光氧化還原催化的未活化烯烴與活性亞甲基化合物的分子間環丙烷化反應。在空氣或氧氣（O2）下的中性溶劑中，該反應借由藍色發光二極管光激發的光氧化還原催化劑和碘輔助催化劑（作為分子碘添加或由烷基碘化物原位生成）進行。
機理研究表明，無論活性亞甲基化合物加成至烯烴還是閉環反應，光敏O2在碳中心自由基的生成中都起著至關重要的作用。
▲ Abstract：
Cyclopropanes are key features in many preclinical, clinical, and commercial drugs, as well as natural products. The most prolific technique for their synthesis is the metal-catalyzed reaction of an alkene with a diazoalkane, a highly energetic reagent requiring stringent safety precautions. Discovery of alternative innocuous reagents remains an ongoing challenge. Herein, we report a simple photoredox-catalyzed intermolecular cyclopropanation of unactivated alkenes with active methylene compounds. The reaction proceeds in neutral solvent under air or dioxygen (O2) with a photoredox catalyst excited by blue light-emitting diode light and an iodine co-catalyst that is either added as molecular iodine or generated in situ from alkyl iodides. Mechanistic investigations indicate that photosensitized O2plays a vital role in the generation of carbon-centered radicals for both the addition of active methylene compounds to alkenes and the ring closure.
地球科學Earth Science
Tremor signals during fluid injection are generated by fault slip
流體注入過程中的震顫信號由斷層滑動產生
▲ 作者：Shankho Niyogi, Abhijit Ghosh, Abhash Kumar & Richard W. Hammack
▲ 鏈接：
https://www.science.org/doi/full/10.1126/science.adh1331
▲ 摘要：
地震震顫信號也被稱為長周期、長持續時間信號，已在幾個為加強油氣勘探而進行流體注入的地方被報道。然而，人們對這些信號的來源仍知之甚少。
研究組分析了堪薩斯州惠靈頓油田的地震震顫信號，在二氧化碳注入項目中使用了地震陣列。他們表明，這些信號是在二氧化碳注入時在地表以下產生的，具有類似于在冰川和火山環境中觀察到的獨特光譜特征。
震源位于注入點附近，并與先前存在的斷層對齊。模擬結果表明，這種地震是由斷層上的摩擦滑動產生的。這些觀測結果可能揭示了一種重要的變形模式，有助于研究相關應力、地震活動性和觸發，以及在所有流體（包括超臨界二氧化碳）注入操作期間跟蹤斷層活動。
▲ Abstract：
Seismic tremor signals, also known as long-period, long-duration signals, have been reported in several locations where fluid injection for enhanced oil and gas exploration is taking place. However, the origin of these signals remains poorly constrained. We studied seismic tremor signals in Wellington Field, Kansas, using a seismic array during a carbon dioxide injection program. We show that these signals are generated below the surface during the time of carbon dioxide injection. They have a distinct spectral signature, similar to those observed in glacial and volcanic environments. The tremor sources are located near the injection site and aligned with preexisting faults. Modeling results imply that such tremors are generated by frictional slip on fault. These observations may reveal an important deformation mode, which is useful for studying associated stress, seismicity, and triggering, as well as for tracking fault activities during injection operations of all fluids, including supercritical carbon dioxide.
空間組學Spatial Omics
The dawn of spatial omics
空間組學的曙光
▲ 作者：Dario Bressan, Giorgia Battistoni & Gregory J. Hannon
▲ 鏈接：
https://www.science.org/doi/full/10.1126/science.abq4964
▲ 摘要：
空間組學被廣泛認為是生命科學的新前沿。這個概念涵蓋一系列廣泛的技術，有望改觀生物學的許多領域，并最終通過同時測量物理組織結構和分子特征來徹底改變病理學。
盡管空間組學在過去5年里已趨成熟，但它仍面臨著一些發展缺陷：進入壁壘、穩健性、實驗設計和分析的最佳實踐不明確，以及缺乏標準化。
在該文中，研究組提出了不同類型空間組學技術的系統目錄；強調其原理、強項和局限性；并就這一非常強大但仍難以駕馭的領域面臨的最大挑戰給出了一些觀點和建議。
▲ Abstract：
