Journal of the American Chemical Society最新文献_第8页

Thermo-Bistable Red and Sensitized Near-Infrared Photoswitches 热双稳红色和敏化近红外光开关

IF 15 1区化学 Q1 CHEMISTRY, MULTIDISCIPLINARY

Journal of the American Chemical Society

Pub Date : 2026-02-04 DOI: 10.1021/jacs.5c20020

Zhiwei Zhang,Zhubin Hu,Lei Huang,Huichao Guo,Jinghong Dai,Long Deng,Guining Gong,Tong Xia,Ruijia Sun,Botao Ji,Wei-Hong Zhu,Junji Zhang,He Tian

Molecular photoswitching in the red and near-infrared (NIR) region is highly sought after for applications in biological systems, optoelectronic devices, and functional materials where low-energy light minimizes photodamage and enables deep-tissue penetration. However, developing photoswitches that simultaneously achieve long-wavelength responsiveness with robust thermal bistability and high quantum efficiency remains a formidable challenge. Here, we report an intrinsic thermo-bistable, red-light-responsive (605 nm/730 nm) photochromic motif based on a perylene bisimide (PBI) scaffold, which further enables an unprecedented sensitized NIR (808 nm/730 nm) photoisomerization through a triplet pathway. Rational side-chain engineering with aryl substituents of distinct aromaticity and electronic character finely tunes the transition-state energy barrier (ΔG‡ = 45.07 kcal mol–1), leading to exceptional thermal stability and a long-lived closed isomer. Further molecular engineering of PBI-based photoswitches also delivers high photoisomerization quantum yield, bright fluorescence, and near-quantitative photoconversion efficiency. This work provides a new photochromic motif that boosts the overall photochemical/thermal performances of molecular photoswitching at the red-light end, thereby enriching the structural and functional landscape of a high-performance photoswitching system. Demonstrations in dynamic cell-membrane imaging further highlight the potential of these PBI-based photoswitches as powerful photochemical platforms for advanced biomedical and optoelectronic applications.

红色和近红外（NIR）区域的分子光电开关在生物系统、光电子器件和功能材料中的应用备受追捧，在这些应用中，低能量光可以最大限度地减少光损伤并实现深层组织穿透。然而，开发同时具有强大的热双稳定性和高量子效率的长波长响应性的光开关仍然是一个艰巨的挑战。在这里，我们报道了一个基于苝二酰亚胺（PBI）支架的固有热双稳态、红光响应（605 nm/730 nm）光致变色基序，该基序进一步通过三重态途径实现了前所未有的近红外（808 nm/730 nm）光异构化。具有不同芳香性和电子特征的芳基取代基的合理侧链工程精细地调节了过渡态能垒（ΔG‡= 45.07 kcal mol-1），从而获得了优异的热稳定性和长寿命的封闭异构体。基于pbi的光开关的进一步分子工程也提供了高光异构量子产率，明亮的荧光和近定量的光转换效率。这项工作提供了一个新的光致变色基序，提高了分子光开关在红光端的整体光化学/热性能，从而丰富了高性能光开关系统的结构和功能景观。动态细胞膜成像的演示进一步突出了这些基于pbi的光开关作为先进生物医学和光电子应用的强大光化学平台的潜力。

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引用次数: 0

Surface-Only Nuclear Magnetic Resonance Spectroscopy by Dynamic Nuclear Polarization and 2H-Dephasing 动态核极化和2h减相的表面核磁共振波谱

IF 15 1区化学 Q1 CHEMISTRY, MULTIDISCIPLINARY

Journal of the American Chemical Society

Pub Date : 2026-02-04 DOI: 10.1021/jacs.5c21534

Tristan Georges,Ran Wei,X. Ray Cowen,Likai Zheng,Michael Grätzel,Lyndon Emsley

Understanding and controlling surface structure at the atomic scale is essential in functional materials, yet direct and selective surface characterization in such systems remains a challenge. Here a broadly applicable strategy for surface-only solid-state NMR enabled by dynamic nuclear polarization (DNP) is introduced. The method exploits partially deuterated vitrified solvents as proximity “probe” molecules and 2H-based dipolar dephasing to filter out signals from the bulk, thereby providing clear detection of nuclei located exclusively in the first one or two atomic layers at the surface (without 1H–2H exchange). Implemented through a 1H–X{2H} CP-REDOR scheme, this approach allows the detection of X through the 2H–X dipolar couplings, which are almost an order of magnitude lower than their 1H–X counterparts, thus providing unprecedented surface selectivity. The applicability of the new method is demonstrated on several compounds including core–shell nanocrystalline hydroxyapatite, tin dioxide, silica, as well as a passivated hybrid perovskite, and surface sites are resolved that would otherwise have been obscured by the bulk signals. Quantitative analysis of the dephasing curves allows interfacial distance measurements to the solvent. This 2H-dephasing DNP approach establishes a versatile platform for the atomic-scale characterization of functional surfaces in both inorganic materials and proton-rich nanomaterials.

在原子尺度上理解和控制表面结构对功能材料至关重要，但在这种系统中直接和选择性的表面表征仍然是一个挑战。本文介绍了一种广泛适用的基于动态核极化（DNP）的表面固态核磁共振策略。该方法利用部分氘化的玻璃化溶剂作为接近“探针”分子和2h基偶极脱相来过滤掉体中的信号，从而清晰地检测到仅位于表面的第一个或两个原子层的原子核（没有1H-2H交换）。通过1H-X {2H} CP-REDOR方案实现，该方法允许通过2H - X偶极耦合检测X，其几乎比1H-X对应物低一个数量级，从而提供前所未有的表面选择性。新方法的适用性在几种化合物上得到了证明，包括核-壳纳米晶羟基磷灰石、二氧化锡、二氧化硅以及钝化的杂化钙钛矿，并且解决了表面位置，否则会被体信号掩盖。定量分析脱相曲线可以测量到溶剂的界面距离。这种2h脱相DNP方法为无机材料和富质子纳米材料的功能表面的原子尺度表征建立了一个通用平台。

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引用次数: 0

Waveform-Enhanced Alternating Current Electrocatalysis Enables Cu-Catalyzed Carbon–Oxygenation of β-Keto Carbonyls with Alkenes and Alkynes 波形增强的交流电催化使cu催化β-酮羰基与烯烃和炔的碳氧合成为可能

IF 15 1区化学 Q1 CHEMISTRY, MULTIDISCIPLINARY

Journal of the American Chemical Society

Pub Date : 2026-02-04 DOI: 10.1021/jacs.5c19029

Qinghong Yang,Linpu Zhou,Bufan Dang,Yeran Liu,Jianxing Wang,Xin Wang,Wei Ding,Zhiqiang Zhang,Yiheng Guo,Jiaxin Yuan,Heng Zhang,Hong Yi,Li Zeng,Aiwen Lei

Alternating current (AC) electrolysis furnishes a dynamic electric field with tunable frequency, duty ratio, and waveform, features that have recently conferred distinct advantages in organic electrosynthesis. In this work, we introduce an unsymmetrical AC waveform-driven Cu-catalyzed oxidative strategy that employs available β-keto carbonyls, alkenes or alkynes to access valuable 5,5-spirocyclic and E-type alkene scaffolds via intra- and intermolecular carbon–oxygenation. Under two distinct waveforms, the reactions proceed smoothly via a Cu-bound radical and nucleophilic addition pathway, respectively. Electron paramagnetic resonance (EPR) studies demonstrate that unsymmetrical AC waveforms maintain a high-concentration dynamic equilibrium of copper intermediates within their respective reaction environments. These findings broaden the scope of AC electrosynthesis and illustrate how waveform design can be leveraged to direct reactivity in challenging bond-forming cascades.

交流电解提供了一个具有可调频率、占空比和波形的动态电场，这些特征最近在有机电合成中被赋予了明显的优势。在这项工作中，我们引入了一种不对称交流波形驱动的cu催化氧化策略，该策略利用可用的β-酮羰基、烯烃或炔，通过分子内和分子间的碳氧作用获得有价值的5,5-螺环和e型烯烃支架。在两种不同的波形下，反应分别通过cu结合自由基和亲核加成途径顺利进行。电子顺磁共振（EPR）研究表明，不对称交流波形在其各自的反应环境中保持了铜中间体的高浓度动态平衡。这些发现扩大了交流电合成的范围，并说明了如何利用波形设计来指导具有挑战性的键形成级联的反应性。

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引用次数: 0

Myoglobin-Membrane Association Facilitates Oxygen Release via Active-Site Tuning 肌红蛋白-膜协会通过活性位点调节促进氧气释放

IF 15 1区化学 Q1 CHEMISTRY, MULTIDISCIPLINARY

Journal of the American Chemical Society

Pub Date : 2026-02-04 DOI: 10.1021/jacs.5c20333

Santiago Di Lella,Ulises A. Zitare,Luciana Capece,Andresa Messias,Juan Cruz Palermo,Daniel H. Murgida,Sara E. Bari,Darío A. Estrin

Myoglobin, a heme protein abundant in striated muscle cells, plays a crucial role in oxygen delivery to mitochondria. In this study, we combined spectroscopy, rapid kinetics and computer simulations to investigate how the interaction between oxymyoglobin and an outer mitochondrial membrane model - composed of 1:1 POPC:POPE liposomes- impacts oxygen affinity. UV–visible and Resonance Raman spectroscopy studies of metmyoglobin, deoxymyoglobin and oxymyoglobin reveal subtle structural perturbations of the heme binding site, when oxymyoglobin interacts with the model membrane. Stopped-flow kinetic measurements show that these distortions lead to a 2-fold increase in the rate constant for oxygen release. Furthermore, classical and multiscale QM/MM simulations suggest that the increase in the O2 dissociation rate in the presence of the liposomes is mainly due to proximal effects and heme plane distortions produced by specific interactions between oxymyoglobin and the membrane. Altogether, these results point to a fine-tuning in the active site conformation that facilitates oxygen release from oxymyoglobin upon membrane association, potentially enhancing mitochondrial oxygen availability and energy production in cells.

肌红蛋白是横纹肌细胞中富含的一种血红素蛋白，在向线粒体输送氧气的过程中起着至关重要的作用。在这项研究中，我们结合了光谱学、快速动力学和计算机模拟来研究氧肌红蛋白与线粒体外膜模型（由1:1的POPC:POPE脂质体组成）之间的相互作用如何影响氧亲和力。紫外可见和共振拉曼光谱对肌红蛋白、脱氧肌红蛋白和氧基肌红蛋白的研究显示，当氧基肌红蛋白与模型膜相互作用时，血红素结合位点发生了细微的结构扰动。停流动力学测量表明，这些变形导致氧气释放速率常数增加2倍。此外，经典和多尺度QM/MM模拟表明，在脂质体存在的情况下，氧解离率的增加主要是由于氧肌红蛋白与膜之间的特定相互作用产生的近端效应和血红素平面扭曲。总之，这些结果指出活性位点构象的微调，促进氧肌红蛋白在膜结合时释放氧气，潜在地提高线粒体氧气的可用性和细胞中的能量产生。

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引用次数: 0

Leveraging Divergent Ligand-to-Metal Charge-Transfer Excited State Pathways for Catalyst Control over Alkoxyl Radical Reactivity 利用分散的配体-金属电荷转移激发态途径控制烷氧基自由基反应活性

IF 15 1区化学 Q1 CHEMISTRY, MULTIDISCIPLINARY

Journal of the American Chemical Society

Pub Date : 2026-02-04 DOI: 10.1021/jacs.5c22609

Zilu Tang,Yetong Lin,Arshad Mehmood,Ashley E. Lojko,Jagrut A. Shah,Noah J. Schwartzapfel,Benjamin G. Levine,Jeffrey M. Lipshultz

Ligand-to-metal charge-transfer (LMCT) excitation has emerged in recent years as a powerful modality in organic synthesis, namely for the generation of heteroatom-centered radicals through formal metal–ligand bond homolysis from the LMCT excited state. However, the exploitation of alternative LMCT excited state processes has been extremely limited. Here, we describe a general strategy for tuning the reaction course from LMCT excited states of titanium alkoxides. This reactivity paradigm has been exploited for tandem β-scission/Giese addition reactions of both scission-amenable and scission-recalcitrant alcohols under divergent reaction pathways of metal–ligand bond homolysis and excited state β-scission through judicious choice of electronically tuned Ti catalysts. Through intramolecular competition studies, catalyst-controlled scission is shown to facilitate a rate enhancement of up to 103-fold over the intrinsic scission of free alkoxyl radicals, highlighting the impact of accessing the excited state scission paradigm. Computations support the relevance of a scission-promoting LMCT excited state with stereoelectronically aligned alkoxyl radical cation character to enable direct, selective β-scission.

近年来，LMCT激发成为有机合成中一种强有力的方式，即从LMCT激发态通过形式金属-配体键均解生成杂原子中心自由基。然而，替代LMCT激发态过程的开发非常有限。在这里，我们描述了从钛醇氧化物的LMCT激发态调整反应过程的一般策略。通过合理选择电子调谐的Ti催化剂，该反应模式已被用于在金属-配体键均裂和激发态β-裂解的不同反应途径下，可裂解和不可裂解醇的串联β-裂解/Giese加成反应。通过分子内竞争研究，催化剂控制的分裂被证明比游离烷氧基自由基的固有分裂促进了高达103倍的速率提高，突出了进入激发态分裂范式的影响。计算支持了促进分裂的LMCT激发态与立体电子排列的烷氧基自由基阳离子特征的相关性，从而实现了直接、选择性的β-分裂。

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引用次数: 0

Protein Electrostatics Tune the Singlet–Triplet Energy Gap in Natural and Engineered Phototropin Light-Oxygen-Voltage (LOV) Domains 蛋白质静电调节天然和工程致光蛋白光氧电压（LOV）结构域的单线态-三重态能隙

IF 15 1区化学 Q1 CHEMISTRY, MULTIDISCIPLINARY

Journal of the American Chemical Society

Pub Date : 2026-02-04 DOI: 10.1021/jacs.5c21945

Stephen O. Ajagbe,Paulami Ghosh,Samer Gozem

Photoactive flavoproteins such as Light-Oxygen-Voltage (LOV) domains serve as scaffolds for tuning the photophysics of their bound flavin cofactor through sequence mutations. This variable tuning effect has led to the development of a series of engineered LOV-based proteins that optimize fluorescence, intersystem crossing (ISC), photoreduction, and/or adduct formation over a range of time scales. To better guide future engineering efforts, we recently employed hybrid quantum mechanical/molecular mechanical (QM/MM) models of LOV domains to study how intradomain electrostatics exert control over flavin’s photophysics. This work focuses on a series of three LOV1 and three LOV2 domains from Arabidopsis thaliana (AtLOV), Avena sativa (AsLOV), and Chlamydomonas reinhardtii (CrLOV), as well as two engineered protein variants used for singlet oxygen generation, miniSOG and SOPP3. The results, which include an analysis of conformational flexibility, energetics of low-lying singlet and triplet π,π* and n,π* states, and protein electrostatic projection maps, shed light on the variations in ISC efficiency in those systems. We found that LOV1 domains are more flexible than LOV2 domains and have consistently higher triplet n,π* (TnN,π*) energies when compared to the first optically active singlet π,π* (S1π,π*) state. This finding corroborates reports in the literature that ISC is typically less efficient in LOV1 domains. We also find that unfavorable triplet state energetics may provide an alternative explanation for a competing adduct formation directly from the singlet S1π,π* state in CrLOV2. In contrast, SOPP3 was found to have a smaller energy gap between the S1π,π* and TnN,π* compared to miniSOG and all other natural LOV domains, which explains its improved ability to sensitize triplet oxygen. Together, these results emphasize the importance of electrostatic tuning in controlling the efficiency of ISC in LOV domains. The results also indicate that a heavy-atom effect alone cannot explain efficient ISC, especially in Cys-devoid systems like SOPP3.

光-氧电压（LOV）结构域等光活性黄蛋白通过序列突变调节其结合的黄素辅因子的光物理特性。这种可变调谐效应导致了一系列基于lovv的工程蛋白的发展，这些蛋白在一定的时间尺度上优化了荧光、系统间交叉（ISC）、光还原和/或加合物的形成。为了更好地指导未来的工程工作，我们最近使用LOV域的混合量子力学/分子力学（QM/MM）模型来研究域内静电如何控制黄素的光物理。本研究的重点是拟南芥（AtLOV）、燕麦（AsLOV）和莱茵衣藻（CrLOV）的三个LOV1和三个LOV2结构域，以及用于单线态氧生成的两个工程蛋白变体miniSOG和SOPP3。结果包括构象柔韧性的分析，低空单重态和三重态π、π*和n、π*态的能量学，以及蛋白质静电投影图，揭示了这些体系中ISC效率的变化。我们发现LOV1结构域比LOV2结构域更灵活，并且与第一个光学活性单重态π，π* (S1π,π*)相比，具有更高的三重态n，π* (TnN,π*)能量。这一发现证实了文献中的报道，即ISC在LOV1结构域中通常效率较低。我们还发现不利的三重态能量学可能为CrLOV2中单线态S1π，π*态直接形成竞争性加合物提供了另一种解释。相比之下，SOPP3在S1π，π*和TnN，π*之间的能隙比miniSOG和所有其他天然LOV结构域更小，这解释了它对三态氧敏化能力的提高。总之，这些结果强调了静电调谐在控制LOV域中ISC效率中的重要性。结果还表明，单靠重原子效应不能解释高效的ISC，特别是在SOPP3这样缺乏cys的系统中。

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引用次数: 0

Concurrent Pressure-Enhanced Magnetic Order and Photoconductivity in Quasi-One-Dimensional Antiferromagnet MnSb2S4 准一维反铁磁体MnSb2S4的同步压力增强磁序和光电导率

IF 15 1区化学 Q1 CHEMISTRY, MULTIDISCIPLINARY

Journal of the American Chemical Society

Pub Date : 2026-02-04 DOI: 10.1021/jacs.5c21160

Chen Li,Ke Liu,Dequan Jiang,En Chen,Yazhou Zhou,Jing Guo,Yonggang Wang

Low-dimensional van der Waals materials constitute fertile ground for exploring intertwined magnetism, transport, and optoelectronics, yet the structural provenance underlying the interplay among diverse quantum orders remains scarcely elucidated. Here, we report a rare case of simultaneous enhancement of magnetic order and photoconductivity in pressurized quasi-one-dimensional antiferromagnet MnSb2S4. Concomitant with a pressure-induced insulator-to-metal transition, MnSb2S4 exhibits a collapse of magnetic order and dramatic positive-to-negative photoconductivity switching at ∼30 GPa. Notably, possible superconductivity emerges with further compression. Detailed structural analyses and theoretical calculations corroborate these anomalous behaviors and unravel sequential pressure-driven orbital and spin crossover of Mn2+, accompanied by opposite evolutions of Jahn–Teller distortions in two inequivalent [MnS6] octahedra. The intriguing electronic and structural evolutions establish MnSb2S4 as a promising candidate for versatile device engineering and offer an ideal platform for deciphering intricate coupling among multiple degrees of freedom.

低维范德华材料为探索相互交织的磁性、输运和光电子学提供了肥沃的土壤，但不同量子阶之间相互作用的结构来源仍然很少阐明。在这里，我们报道了一个罕见的在加压的准一维反铁磁体MnSb2S4中磁有序和光电导率同时增强的情况。伴随着压力诱导的绝缘体到金属的转变，MnSb2S4在~ 30 GPa时表现出磁性秩序的崩溃和戏剧性的正负光导转换。值得注意的是，随着进一步压缩，可能出现超导性。详细的结构分析和理论计算证实了这些异常行为，并揭示了Mn2+的顺序压力驱动轨道和自旋交叉，伴随着两个不相等的[MnS6]八面体中Jahn-Teller扭曲的相反演变。有趣的电子和结构演变使MnSb2S4成为多功能器件工程的有前途的候选者，并为破译多个自由度之间复杂的耦合提供了理想的平台。

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引用次数: 0

Superconductivity of 30.4 K and Its Reemergence under Pressure in Fe1.11Se Synthesized via Ion-Exchange and Deintercalation Reaction 离子交换脱插反应合成Fe1.11Se中30.4 K的超导性及其在压力下的再现

IF 15 1区化学 Q1 CHEMISTRY, MULTIDISCIPLINARY

Journal of the American Chemical Society

Pub Date : 2026-02-04 DOI: 10.1021/jacs.5c22761

Mingzhang Yang,Yuxin Ma,Qi Li,Ke Ma,Jiali Lu,Zhaolong Liu,Ruijin Sun,Tianping Ying,Mengdi Wang,Xin Chen,Changchun Zhao,Jian-gang Guo,Shifeng Jin,Xiaolong Chen

Binary stoichiometry FeSe (s-FeSe) is a well-known parent of high-temperature unconventional superconductors owing to its charge-neutral layer, highly tunable structure and electronic properties, and rich interplay among multiple electronic phases. Yet, the s-FeSe synthesized via high-temperature equilibrium reactions bears the notorious interstitial Fe, where merely 3% of them is sufficient to kill the superconductivity. Here, we successfully synthesized a new nonstoichiometric Fe1.11Se single crystal with a superconducting onset temperature (Tconset) of 30.4 K through a hydrothermal ion-exchange and deintercalation route. 11% interstitial Fe ions exceed the equilibrium phase diagram limit. Intriguingly, under physical pressure, the Tconset of Fe1+δSe1–xSx exhibits a “V”-shaped evolution with a minimum at 2–2.6 GPa and then upturning into a second superconducting region, reminiscent of the behaviors in FeSe-intercalates. Furthermore, a pressure-induced possible magnetic order, previously observed only in pressurized s-FeSe, shows up. These results offer fresh insights into the role of interstitial Fe in governing superconducting and transport properties under nonequilibrium synthesis and tuning strategies.

二元化学计量FeSe （s-FeSe）由于其电荷中性层、高度可调的结构和电子特性以及多电子相之间丰富的相互作用而成为高温非常规超导体的母体。然而，通过高温平衡反应合成的s-FeSe具有臭名昭著的间隙铁，其中仅3%就足以杀死超导性。本文通过水热离子交换和脱嵌的方法，成功合成了一种新的非化学计量Fe1.11Se单晶，其超导起始温度为30.4 K。11%的间隙铁离子超过平衡相图极限。有趣的是，在物理压力下，Fe1+ δSe1-xSx的Tconset呈现出“V”形演化，最小值为2-2.6 GPa，然后向上进入第二超导区，与fese - interintertes中的行为相似。此外，一种压力诱导的可能的磁顺序，以前只在加压s-FeSe中观察到，也出现了。这些结果为间隙铁在非平衡合成和调谐策略下控制超导和输运性质的作用提供了新的见解。

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引用次数: 0

Supramolecular-Based Ion Separation Membranes for Direct Separation of Concentrated Mixed-Salt Solutions. 直接分离浓缩混合盐溶液的超分子离子分离膜。

IF 15.6 1区化学 Q1 CHEMISTRY, MULTIDISCIPLINARY

Journal of the American Chemical Society

Pub Date : 2026-02-04 DOI: 10.1021/jacs.5c16874

Chengcheng Li, Shen Li, Yajie Zhong, Ting Wang, Xinlong Tian, Mingxin Zhang, Wei Huang

Efficient ion separation from concentrated brines is critical for sustainable water resource utilization, zero-liquid discharge, and strategic ion recovery, yet it remains a formidable challenge for conventional ion-selective membranes (ISMs). Existing ISMs rely on weak ion-pore interactions, limiting their applicability to dilute solutions, whereas stronger binding designs often impose high diffusion barriers that suppress flux. Here, we report a supramolecular ISM in which 18-crown-6 (18C6) macrocycles are integrated into the one-dimensional nanochannels of covalent organic frameworks (COFs), forming a dual-channel architecture─supramolecular pathways for cations and macrocycle-separated free channels for anions. This design minimizes ion interference while enabling strong monovalent-ion recognition and rapid transport. As a result, the 18C6-COF membrane operates effectively in concentrated solutions, achieving high selectivity (S_K⁺/Mg²⁺ = 254.7) and fast permeation (P_K⁺ = 2403 mmol m^-2 h^-1), outperforming state-of-the-art ISMs. Experimental and simulation results show that monovalent cations migrate rapidly through the aligned 1D 18C6 channels via a knock-on-like process, even under strong ion-pore interactions, overcoming the traditional trade-off between binding affinity and transport kinetics. This study lays the groundwork for developing membranes with strong ion-channel interactions for high-concentration mixed-salt separation.

从浓盐水中高效分离离子对水资源的可持续利用、零液体排放和战略性离子回收至关重要，但传统离子选择膜（ISMs）仍然面临着巨大的挑战。现有的ISMs依赖于弱离子孔相互作用，限制了它们对稀溶液的适用性，而更强的结合设计通常施加高扩散屏障，从而抑制通量。在这里，我们报道了一个超分子ISM，其中18冠6 （18C6）大环被整合到共价有机框架（COFs）的一维纳米通道中，形成了双通道结构─阳离子的超分子通道和阴离子的大环分离自由通道。这种设计最大限度地减少了离子干扰，同时实现了强的单价离子识别和快速传输。因此，18C6-COF膜在浓溶液中有效运行，具有高选择性（SK+/Mg2+ = 254.7）和快速渗透（PK+ = 2403 mmol m-2 h-1），优于最先进的ISMs。实验和模拟结果表明，即使在强离子孔相互作用下，一价阳离子也能通过类似敲敲的过程在排列的1D 18C6通道中快速迁移，克服了传统的结合亲和力和运输动力学之间的权衡。该研究为开发具有强离子通道相互作用的高浓度混合盐分离膜奠定了基础。

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引用次数: 0

Polysaccharide Meets Polyoxazoline: Regio- and Stereodefined β-1,2-Linked Pseudo-polysaccharides via Controlled Cationic Ring-Opening Polymerization. 多糖与聚恶唑啉相遇：通过可控阳离子开环聚合制备的区域和立体定向β-1,2链伪多糖。

IF 15.6 1区化学 Q1 CHEMISTRY, MULTIDISCIPLINARY

Journal of the American Chemical Society

Pub Date : 2026-02-03 DOI: 10.1021/jacs.5c19479

Serena I Joseph, Ariana M Hernandez, Serena Summers, Cassandra E Callmann

Polysaccharides exhibit remarkable stereochemical and regiochemical complexity, yet their natural heterogeneity produces differences in composition and material behavior that are difficult to control or predict. Here, we report a synthetic approach that overcomes these challenges through the controlled, cationic ring-opening polymerization of glucosamine-derived 2-oxazoline monomers, affording a new class of well-defined pseudo-polysaccharides, wherein each saccharide subunit is 1,2-N-linked through a nitrogen containing a pendant acyl group. Under optimized conditions using a benzyl-protected monomer (OBn-GlcOx) and a methyl tosylate initiator, polymerization proceeds to full conversion within 3 h at 75 °C with linear molecular weight growth, first-order kinetics, and low dispersity (D̵ ≤ 1.2), consistent with a controlled polymerization mechanism. The resulting polymers exhibit complete β-1,2-regio- and stereoselectivity, narrow molecular-weight distributions, and retention of chain-end functionality that enables chain extension to form diblock copolymers with 2-methyl-2-oxazoline. Following quantitative deprotection, the resulting polymer is water-soluble and both protected and nonprotected versions display markedly enhanced resistance to ultrasonic, acidic, and thermal degradation as compared to chitosan (mass loss ≤63% vs 93% under harshest conditions). These findings establish a synthetic route to stereoregular, amide-linked pseudo-polysaccharides with tunable physicochemical properties, expanding the accessible design space for well-defined, carbohydrate-based materials.

多糖表现出显著的立体化学和区域化学复杂性，但它们的天然异质性产生了难以控制或预测的组成和物质行为的差异。在这里，我们报告了一种合成方法，通过控制，阳离子开环聚合的氨基衍生的2-恶唑啉单体，克服了这些挑战，提供了一类新的明确定义的伪多糖，其中每个糖亚基是1,2- n通过一个含垂链酰基的氮连接。在优化的条件下，使用苯基保护单体（OBn-GlcOx）和甲酯引发剂，聚合在75℃下3小时内进行完全转化，分子量线性增长，一级动力学，低分散性（D′≤1.2），符合可控的聚合机制。所得聚合物具有完整的β-1,2区域和立体选择性，窄分子量分布，以及保留链端功能，使链延伸与2-甲基-2-恶唑啉形成二嵌段共聚物。定量去保护后，得到的聚合物是水溶性的，与壳聚糖相比，受保护和未受保护的聚合物都表现出明显增强的抗超声波、酸性和热降解的能力（质量损失≤63%，在最恶劣的条件下为93%）。这些发现建立了一条合成具有可调物理化学性质的立体规则、酰胺连接的伪多糖的合成路线，扩大了明确的碳水化合物基材料的可访问设计空间。

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引用次数: 0