Science, 18 NOVEMBER 2022, VOL 378, ISSUE 6621
《科学》, 2022年11月18日，第378卷，6621期
物理学Physics
Cavity-enabled enhancement of ultrafast intramolecular vibrational redistribution over pseudorotation
伪旋转作用下超快分子内振动重分布的空腔增强
▲ 作者：TENG-TENG CHEN, MATTHEW DU, ZIMO YANG, JOEL YUEN-ZHOU AND WEI XIONG.
▲ 链接：
https://www.science.org/doi/10.1126/science.add0276
▲ 摘要：
分子振动和微腔光子之间的振动强耦合（VSC）产生少量的极化激元（光-物质模式）和许多暗模式（光子特性可以忽略不计）。尽管据报道VSC可以改变热激活的化学反应，但其机制仍不清楚。
为了阐明这一问题，研究组跟踪了五羰基铁[Fe(CO)5]在VSC作用下的简易单分子振动能量交换的超快动力学，其表现出两个相互竞争的途径：伪旋转和分子内振动-能量再分配（IVR）。
结果发现，在极化激元的激发下，能量交换整体加速，IVR速度变快，伪旋转速度变慢。然而，暗模式激发显示的动力学与腔外相比没有变化，伪旋转占主导地位。
因此，尽管热激活VSC修饰化学存在争议，但该工作表明，VSC确实可通过非平衡制备极化激元来改变化学。
▲ Abstract：
Vibrational strong coupling (VSC) between molecular vibrations and microcavity photons yields a few polaritons (light-matter modes) and many dark modes (with negligible photonic character). Although VSC is reported to alter thermally activated chemical reactions, its mechanisms remain opaque. To elucidate this problem, we followed ultrafast dynamics of a simple unimolecular vibrational energy exchange in iron pentacarbonyl [Fe(CO)5] under VSC, which showed two competing channels: pseudorotation and intramolecular vibrational-energy redistribution (IVR). We found that under polariton excitation, energy exchange was overall accelerated, with IVR becoming faster and pseudorotation being slowed down. However, dark-mode excitation revealed unchanged dynamics compared with those outside of the cavity, with pseudorotation dominating. Thus, despite controversies around thermally activated VSC modified chemistry, our work shows that VSC can indeed alter chemistry through a nonequilibrium preparation of polaritons.
Noise-resilient edge modes on a chain of superconducting qubits
超导量子比特链上的抗噪声边缘模
▲ 作者：X. MI, M. SONNER, M. Y. NIU, K. W. LEE, B. FOXEN, R. ACHARYA, ET AL.
▲ 链接：
https://www.science.org/doi/10.1126/science.abq5769
▲ 摘要：
量子系统的固有对称性可保护其原本脆弱的状态。利用这种保护需要测试其对抗不受控环境交互作用的鲁棒性。
通过47个超导量子比特，研究组实现了具有ℤ2奇偶对称性的非局域马约拉纳边缘模（MEMs）的一维“踢”伊辛模型。他们发现，与MEMs重叠的任何多量子比特泡利算符都表现出与单量子比特弛豫率相当的均匀延迟衰减率，无论其大小或组成如何。
这一特性使人们能够准确地重建MEMs的指数局部空间分布。此外，由于预热化机制，MEMs可适应某些对称性破环噪声。该工作阐明了在固态环境中噪声和对称保护边缘模之间的复杂相互作用。
▲ Abstract：
Inherent symmetry of a quantum system may protect its otherwise fragile states. Leveraging such protection requires testing its robustness against uncontrolled environmental interactions. Using 47 superconducting qubits, we implement the one-dimensional kicked Ising model, which exhibits nonlocal Majorana edge modes (MEMs) with ℤ2 parity symmetry. We find that any multiqubit Pauli operator overlapping with the MEMs exhibits a uniform late-time decay rate comparable to single-qubit relaxation rates, irrespective of its size or composition. This characteristic allows us to accurately reconstruct the exponentially localized spatial profiles of the MEMs. Furthermore, the MEMs are found to be resilient against certain symmetry-breaking noise owing to a prethermalization mechanism. Our work elucidates the complex interplay between noise and symmetry-protected edge modes in a solid-state environment.
材料科学Materials Science
Initializing film homogeneity to retard phase segregation for stable perovskite solar cells
初始化薄膜均匀性以延缓稳定钙钛矿太阳能电池的相分离
▲ 作者：YANG BAI, ZIJIAN HUANG, XIAO ZHANG, JIUZHOU LU, XIUXIU NIU, ZIWEN HE, ET AL.
▲ 链接：
https://www.science.org/doi/10.1126/science.abn3148
▲ 摘要：
用于高性能太阳能电池的杂化卤化物钙钛矿中使用的阴阳离子混合物经常发生元素和相分离，这限制了器件的使用寿命。
研究组采用谢林偏析模型来研究单个阳离子的迁移，发现初始薄膜的不均匀性加速了材料的降解。通过添加硒酚制备钙钛矿薄膜（FA1–xCsxPbI3；其中FA为甲脒）可导致均匀的阳离子分布，延缓了材料加工和设备运行中的阳离子聚集。
制备的器件效率大幅提升，在1倍太阳光照的最大功率点下运行3190小时后，仍保持其初始效率的91%。研究组还观察到初始均质FACsPb(Br0.13I0.87)3吸收体延长了器件的使用寿命。
▲ Abstract：
The mixtures of cations and anions used in hybrid halide perovskites for high-performance solar cells often undergo element and phase segregation, which limits device lifetime. We adapted Schelling’s model of segregation to study individual cation migration and found that the initial film inhomogeneity accelerates materials degradation. We fabricated perovskite films (FA1–xCsxPbI3; where FA is formamidinium) through the addition of selenophene, which led to homogeneous cation distribution that retarded cation aggregation during materials processing and device operation. The resultant devices achieved enhanced efficiency and retained >91% of their initial efficiency after 3190 hours at the maximum power point under 1 sun illumination. We also observe prolonged operational lifetime in devices with initially homogeneous FACsPb(Br0.13I0.87)3 absorbers.
Mechanical nanolattices printed using nanocluster-based photoresists
使用基于纳米簇光刻胶印刷的机械纳米晶格
▲ 作者：QI LI, JOHN KULIKOWSKI, DAVID DOAN, OTTMAN A. TERTULIANO, CHARLES J. ZEMAN IV, MELODY M. WANG, ET AL.
▲ 链接：
https://www.science.org/doi/10.1126/science.abo6997
▲ 摘要：
天然材料因其具有优化的层次结构、各向异性和纳米孔隙率的纳米结构、纳米复合结构而呈现出新兴机械性能。目前制造这样复杂的系统颇具挑战性，因为高质量的三维（3D）纳米打印大多限于简单、均匀的材料。
研究组报道了一种利用金属纳米簇快速纳米打印复杂结构纳米复合材料的策略。这些超小、量子受限的纳米簇可作为高度敏感的双光子激活剂，同时作为机械增强剂和纳米级致孔剂的前驱体。
研究组已打印出具有复杂3D结构以及具有可调、分层和各向异性纳米孔隙率结构的纳米复合材料。纳米簇-聚合物纳米晶格具有高比强度、能量吸收、可变形性和可恢复性。
该框架提供了一种可推广、通用的方法，有望实现光活性纳米材料应用于具有新兴机械性能的复杂系统增材制造。
▲ Abstract：
Natural materials exhibit emergent mechanical properties as a result of their nanoarchitected, nanocomposite structures with optimized hierarchy, anisotropy, and nanoporosity. Fabrication of such complex systems is currently challenging because high-quality three-dimensional (3D) nanoprinting is mostly limited to simple, homogeneous materials. We report a strategy for the rapid nanoprinting of complex structural nanocomposites using metal nanoclusters. These ultrasmall, quantum-confined nanoclusters function as highly sensitive two-photon activators and simultaneously serve as precursors for mechanical reinforcements and nanoscale porogens. Nanocomposites with complex 3D architectures are printed, as well as structures with tunable, hierarchical, and anisotropic nanoporosity. Nanocluster-polymer nanolattices exhibit high specific strength, energy absorption, deformability, and recoverability. This framework provides a generalizable, versatile approach for the use of photoactive nanomaterials in additive manufacturing of complex systems with emergent mechanical properties.
化学Chemistry
Halogenation of the 3-position of pyridines through Zincke imine intermediates
Zincke亚胺中间体对吡啶3-位的卤化反应
▲ 作者：BENJAMIN T. BOYLE, JEFFREY N. LEVY, LOUIS DE LESCURE, ROBERT S. PATON, AND ANDREW MCNALLY.
▲ 链接：
https://www.science.org/doi/10.1126/science.add8980
▲ 摘要：
吡啶卤化反应对于获得药物和农药开发所需的大量衍生物至关重要。然而，尽管经过了一个多世纪的合成努力，仍难以实现使广泛吡啶前体的3-位C-H键选择性官能化的卤化过程。
研究组报道了一个吡啶基开环、卤化和闭环的反应序列，其中无环Zincke亚胺中间体在温和条件下发生高度区域选择性的卤化反应。
实验和计算机理研究表明，卤素亲电试剂的性质可改变选择性决定步骤。使用这种方法，研究组合成了一系列不同的3-卤代吡啶，并演示了复杂药物和农药的后期卤化。
▲ Abstract：
Pyridine halogenation reactions are crucial for obtaining the vast array of derivatives required for drug and agrochemical development. However, despite more than a century of synthetic endeavors, halogenation processes that selectively functionalize the carbon–hydrogen bond in the 3-position of a broad range of pyridine precursors remain largely elusive. We report a reaction sequence of pyridyl ring opening, halogenation, and ring closing whereby the acyclic Zincke imine intermediates undergo highly regioselective halogenation reactions under mild conditions. Experimental and computational mechanistic studies indicate that the nature of the halogen electrophile can modify the selectivity-determining step. Using this method, we produced a diverse set of 3-halopyridines and demonstrated late-stage halogenation of complex pharmaceuticals and agrochemicals.
Radical and ionic meta-C–H functionalization of pyridines, quinolines, and isoquinolines
吡啶、喹啉和异喹啉的自由基和离子间位C-H官能化
▲ 作者：HUI CAO, QIANG CHENG AND ARMIDO STUDER.
▲ 链接：
https://www.science.org/doi/10.1126/science.ade6029
▲ 摘要：
吡啶的碳-氢（C-H）官能化是许多农药、药品和材料的快速构建和衍生化的有力工具。由于吡啶的固有电子性质，选择性间位 C-H官能化颇具挑战性。
研究组提出了一种通过氧化还原-中性脱芳构化-再芳构化过程，以进行高度区域选择性的间位C-H三氟甲基化、全氟烷基化、氯化、溴化、碘化、硝化、磺化和吡啶硒化的方案。
引入的脱芳烃激活模式为吡啶和其他氮杂芳烃通过自由基和离子途径进行间位选择性反应提供了多样化平台。这些无催化剂反应的广泛范围和高选择性使其适用于药物的后期功能化。
▲ Abstract：
Carbon-hydrogen (C?H) functionalization of pyridines is a powerful tool for the rapid construction and derivatization of many agrochemicals, pharmaceuticals, and materials. Because of the inherent electronic properties of pyridines, selective meta-C?H functionalization is challenging. Here, we present a protocol for highly regioselective meta-C?H trifluoromethylation, perfluoroalkylation, chlorination, bromination, iodination, nitration, sulfanylation, and selenylation of pyridines through a redox-neutral dearomatization-rearomatization process. The introduced dearomative activation mode provides a diversification platform for meta-selective reactions on pyridines and other azaarenes through radical as well as ionic pathways. The broad scope and high selectivity of these catalyst-free reactions render these processes applicable for late-stage functionalization of drugs.
转自：“科学网”微信公众号
如有侵权，请联系本站删除！
