Pub Date : 2024-11-18DOI: 10.1016/j.chempr.2024.10.019
Wenhao Ren, Huanlei Zhang, Miyeon Chang, Nanjun Chen, Wenchao Ma, Jun Gu, Meng Lin, Xile Hu
Zero-gap membrane electrode assembly (MEA) CO electrolyzer stands as a promising technology for circular carbon economy. However, current CO electrolyzers are energetically inefficient when operating at ampere-level current densities. Here, by analyzing the performance discrepancies between MEA and flow cells, we identify the depletion of K+ and water at the cathode as the main contributor to the low performance of MEA CO electrolyzers. This is attributed to the unique cathodic interface in catholyte-free MEA, where there is no aqueous electrolyte to maintain the three-phase interface. Through the development of needle-array catalysts with intensified electric fields (EFs) at their tips, we are able to concentrate the limited K+ cations onto the tips of the cathode, while simultaneously facilitating water uptake via electro-osmosis. We construct an MEA CO electrolyzer that achieves a large current density of 2,500 mA cm−2 at a voltage of only 2.7 V.
零间隙膜电极组件（MEA）一氧化碳电解槽是一种很有前途的循环碳经济技术。然而，目前的二氧化碳电解槽在安培级电流密度下运行时能量效率较低。在这里，通过分析 MEA 和流动电池之间的性能差异，我们发现阴极的 K+ 和水耗尽是导致 MEA CO 电解槽性能低下的主要原因。这归因于无阴极电解质 MEA 中独特的阴极界面，即没有水电解质来维持三相界面。通过开发针状阵列催化剂，并在其顶端加强电场 (EF)，我们能够将有限的 K+ 阳离子集中到阴极顶端，同时通过电渗透促进水的吸收。我们构建的 MEA CO 电解槽在电压仅为 2.7 V 的情况下可达到 2,500 mA cm-2 的大电流密度。
{"title":"Field-enhanced CO electroreduction in membrane electrolyzers at a dehydrated interface","authors":"Wenhao Ren, Huanlei Zhang, Miyeon Chang, Nanjun Chen, Wenchao Ma, Jun Gu, Meng Lin, Xile Hu","doi":"10.1016/j.chempr.2024.10.019","DOIUrl":"https://doi.org/10.1016/j.chempr.2024.10.019","url":null,"abstract":"Zero-gap membrane electrode assembly (MEA) CO electrolyzer stands as a promising technology for circular carbon economy. However, current CO electrolyzers are energetically inefficient when operating at ampere-level current densities. Here, by analyzing the performance discrepancies between MEA and flow cells, we identify the depletion of K<sup>+</sup> and water at the cathode as the main contributor to the low performance of MEA CO electrolyzers. This is attributed to the unique cathodic interface in catholyte-free MEA, where there is no aqueous electrolyte to maintain the three-phase interface. Through the development of needle-array catalysts with intensified electric fields (EFs) at their tips, we are able to concentrate the limited K<sup>+</sup> cations onto the tips of the cathode, while simultaneously facilitating water uptake via electro-osmosis. We construct an MEA CO electrolyzer that achieves a large current density of 2,500 mA cm<sup>−2</sup> at a voltage of only 2.7 V.","PeriodicalId":268,"journal":{"name":"Chem","volume":"36 1","pages":""},"PeriodicalIF":23.5,"publicationDate":"2024-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142665346","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-14DOI: 10.1016/j.chempr.2024.07.033
Nikita Y. Gugin , Kirill V. Yusenko , Andrew King , Klas Meyer , Dominik Al-Sabbagh , Jose A. Villajos , Franziska Emmerling
Mechanochemistry is an environmentally friendly synthetic approach that enables the sustainable production of a wide range of chemicals while reducing or eliminating the need for solvents. Reactive extrusion aims to move mechanochemistry from its conventional gram-scale batch reactions, typically performed in laboratory ball mills, to a continuous, large-scale process. Meeting this challenge requires in situ monitoring techniques to gain insights into reactive extrusion and its underlying processes. While the effectiveness of in situ Raman spectroscopy in providing molecular-level information has been demonstrated, our study uses energy-dispersive X-ray diffraction to monitor reactive extrusion in real time at the crystalline level. Our results provide previously unavailable control over the reactive extrusion process, promoting its perception as an industrially feasible green alternative to traditional solvent-based syntheses.
Video abstract
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机械化学是一种环境友好型合成方法，可实现多种化学品的可持续生产，同时减少或消除对溶剂的需求。反应挤压法旨在将机械化学从传统的克级批量反应（通常在实验室球磨机中进行）转变为连续的大规模工艺。要应对这一挑战，需要采用原位监测技术来深入了解反应挤压及其基本过程。虽然原位拉曼光谱在提供分子级信息方面的有效性已得到证实，但我们的研究利用能量色散 X 射线衍射技术在晶体级实时监测反应挤压。我们的研究结果提供了以前无法获得的对反应性挤压过程的控制，促进了人们对反应性挤压作为传统溶剂型合成的一种工业上可行的绿色替代方法的认识。视频摘要下载：下载视频 (18MB)
{"title":"Lighting up industrial mechanochemistry: Real-time in situ monitoring of reactive extrusion using energy-dispersive X-ray diffraction","authors":"Nikita Y. Gugin , Kirill V. Yusenko , Andrew King , Klas Meyer , Dominik Al-Sabbagh , Jose A. Villajos , Franziska Emmerling","doi":"10.1016/j.chempr.2024.07.033","DOIUrl":"10.1016/j.chempr.2024.07.033","url":null,"abstract":"<div><div>Mechanochemistry is an environmentally friendly synthetic approach that enables the sustainable production of a wide range of chemicals while reducing or eliminating the need for solvents. Reactive extrusion aims to move mechanochemistry from its conventional gram-scale batch reactions, typically performed in laboratory ball mills, to a continuous, large-scale process. Meeting this challenge requires <em>in situ</em> monitoring techniques to gain insights into reactive extrusion and its underlying processes. While the effectiveness of <em>in situ</em> Raman spectroscopy in providing molecular-level information has been demonstrated, our study uses energy-dispersive X-ray diffraction to monitor reactive extrusion in real time at the crystalline level. Our results provide previously unavailable control over the reactive extrusion process, promoting its perception as an industrially feasible green alternative to traditional solvent-based syntheses.</div></div><div><h3>Video abstract</h3><div><span><span><span><span><video><source></source></video></span><span><span>Download: <span>Download video (18MB)</span></span></span></span></span></span></div></div>","PeriodicalId":268,"journal":{"name":"Chem","volume":"10 11","pages":"Pages 3459-3473"},"PeriodicalIF":19.1,"publicationDate":"2024-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142085779","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-14DOI: 10.1016/j.chempr.2024.09.022
Da Zhao , Tobias Ritter
Late-stage deuteration is a crucial technique in the pharmaceutical industry. Direct aromatic deuteration without the use of directing groups or transition-metal catalysts presents a substantial challenge. Now, through the integration of an interrupted Birch reduction, Liang, Xia, and co-workers have developed a photochemical protocol for the efficient hydrogen isotope exchange to incorporate deuterium into the arenes of pharmaceuticals.
{"title":"Illuminating aromatic deuteration","authors":"Da Zhao , Tobias Ritter","doi":"10.1016/j.chempr.2024.09.022","DOIUrl":"10.1016/j.chempr.2024.09.022","url":null,"abstract":"<div><div>Late-stage deuteration is a crucial technique in the pharmaceutical industry. Direct aromatic deuteration without the use of directing groups or transition-metal catalysts presents a substantial challenge. Now, through the integration of an interrupted Birch reduction, Liang, Xia, and co-workers have developed a photochemical protocol for the efficient hydrogen isotope exchange to incorporate deuterium into the arenes of pharmaceuticals.</div></div>","PeriodicalId":268,"journal":{"name":"Chem","volume":"10 11","pages":"Pages 3266-3267"},"PeriodicalIF":19.1,"publicationDate":"2024-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142487534","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-14DOI: 10.1016/j.chempr.2024.10.014
Wenbin Huang , Zhe Dong
In this issue of Chem, Popescu and Paton report a new method to predict triplet energy sensitization of small molecules by sampling the instantaneous vertical energy gaps over molecular vibrational motions. This approach has reduced the mean absolute error of predicting ET from 9.5 to 1.7 kcal/mol compared with previous state-of-the-art methods.
在本期《化学》杂志上，Popescu 和 Paton 报告了一种通过对分子振动运动的瞬时垂直能隙采样来预测小分子三重能敏化的新方法。与以前最先进的方法相比，这种方法将预测 ET 的平均绝对误差从 9.5 千卡/摩尔减少到 1.7 千卡/摩尔。
{"title":"Accurate triplet energies prediction method based on the hot-band model","authors":"Wenbin Huang , Zhe Dong","doi":"10.1016/j.chempr.2024.10.014","DOIUrl":"10.1016/j.chempr.2024.10.014","url":null,"abstract":"<div><div>In this issue of <em>Chem</em>, Popescu and Paton report a new method to predict triplet energy sensitization of small molecules by sampling the instantaneous vertical energy gaps over molecular vibrational motions. This approach has reduced the mean absolute error of predicting E<sub>T</sub> from 9.5 to 1.7 kcal/mol compared with previous state-of-the-art methods.</div></div>","PeriodicalId":268,"journal":{"name":"Chem","volume":"10 11","pages":"Pages 3270-3272"},"PeriodicalIF":19.1,"publicationDate":"2024-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142556260","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-14DOI: 10.1016/j.chempr.2024.08.001
Liangxuan Xu , Du Chen , Peng Zhang , Chungu Xia , Chao Liu
Alkynes have played pivotal roles in numerous synthetic transformations and materials science. Here, by developing nitrogen-deletion coupling, we describe a modular synthesis of alkynes from widely accessible nitriles by swapping the N atom to a C atom in cyano groups, where lithiated gem-diborylalkanes and tert-butyl nitrite are applied sequentially. NMR analysis and crystal structure show the nature of an intermediary α-boryl lithium enamine. A diverse range of nitriles are converted into various internal and terminal alkynes within a short reaction time, including alkynes bearing bulky secondary and tertiary alkyl substituents on both sides.
炔烃在众多合成转化和材料科学中发挥着关键作用。在这里，通过开发缺氮偶联，我们描述了一种通过将氰基中的 N 原子换成 C 原子，从广泛可得的腈中模块化合成炔烃的方法。核磁共振分析和晶体结构显示了中间体 α-硼烷基烯胺锂的性质。在很短的反应时间内，各种腈类都能转化为各种内部和末端炔烃，包括两侧都带有笨重的仲烷基和叔烷基取代基的炔烃。
{"title":"Atom swap in triple bonds via nitrogen-deletion coupling with gem-diborylalkanes","authors":"Liangxuan Xu , Du Chen , Peng Zhang , Chungu Xia , Chao Liu","doi":"10.1016/j.chempr.2024.08.001","DOIUrl":"10.1016/j.chempr.2024.08.001","url":null,"abstract":"<div><div>Alkynes have played pivotal roles in numerous synthetic transformations and materials science. Here, by developing nitrogen-deletion coupling, we describe a modular synthesis of alkynes from widely accessible nitriles by swapping the N atom to a C atom in cyano groups, where lithiated <em>gem</em>-diborylalkanes and <em>tert</em>-butyl nitrite are applied sequentially. NMR analysis and crystal structure show the nature of an intermediary α-boryl lithium enamine. A diverse range of nitriles are converted into various internal and terminal alkynes within a short reaction time, including alkynes bearing bulky secondary and tertiary alkyl substituents on both sides.</div></div>","PeriodicalId":268,"journal":{"name":"Chem","volume":"10 11","pages":"Pages 3474-3487"},"PeriodicalIF":19.1,"publicationDate":"2024-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142138192","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-14DOI: 10.1016/j.chempr.2024.06.015
Yi Zhao , Qingqing Gu , Xue Sun , Dong Wang , Xueqing Gong , Bing Yang , Jing Xu , Bo Peng , Ying Zhang , Chengsi Pan , Yongfa Zhu , Yang Lou
Developing a new tactic for directionally regulating a specific functional group of feedstock molecules at the molecular level is highly desired to synthesize high-value products but remains challenging. We design and construct the two-dimensional molybdenum disulfide (2D MoS2) nanosheets edge-anchored dual Rh atoms (Rh2/MoS2 dual-atom catalyst [DAC]) to boost the ethanol yield in dimethyl oxalate (DMO) selective hydrogenation by precisely manipulating the DMO adsorption configuration. Comprehensive experimental and theoretical results reveal that the pocket-like active center of Rh2 atoms, with a precise metal-metal distance (3.5 Å), realizes the spatially matched bidentate DMO adsorption via two C=O groups (distance of 3.1 Å), which remarkably enhances the DMO activation and drives the production of ethanol via a unilateral activation mechanism. The turnover frequency (TOF) and H2/DMO molar ratio of Rh2/MoS2 DAC are around 19 times higher and 17 times lower, respectively, than those of the best reported catalysts under comparable conditions. Our results offer practical opportunities for updating the industrial syngas-DMO-ethanol route.
{"title":"Steric-confinement Rh2/MoS2 dual-atom catalyst directionally modulating adsorption configuration of ester group to boost ethanol synthesis","authors":"Yi Zhao , Qingqing Gu , Xue Sun , Dong Wang , Xueqing Gong , Bing Yang , Jing Xu , Bo Peng , Ying Zhang , Chengsi Pan , Yongfa Zhu , Yang Lou","doi":"10.1016/j.chempr.2024.06.015","DOIUrl":"10.1016/j.chempr.2024.06.015","url":null,"abstract":"<div><div><span><span>Developing a new tactic for directionally regulating a specific functional group of feedstock molecules at the molecular level is highly desired to synthesize high-value products but remains challenging. We design and construct the two-dimensional </span>molybdenum disulfide (2D MoS</span><sub>2</sub><span>) nanosheets edge-anchored dual Rh atoms (Rh</span><sub>2</sub>/MoS<sub>2</sub><span> dual-atom catalyst [DAC]) to boost the ethanol yield in dimethyl oxalate (DMO) selective hydrogenation by precisely manipulating the DMO adsorption configuration. Comprehensive experimental and theoretical results reveal that the pocket-like active center of Rh</span><sub>2</sub><span> atoms, with a precise metal-metal distance (3.5 Å), realizes the spatially matched bidentate DMO adsorption via two C=O groups (distance of 3.1 Å), which remarkably enhances the DMO activation and drives the production of ethanol via a unilateral activation mechanism. The turnover frequency (TOF) and H</span><sub>2</sub>/DMO molar ratio of Rh<sub>2</sub>/MoS<sub>2</sub> DAC are around 19 times higher and 17 times lower, respectively, than those of the best reported catalysts under comparable conditions. Our results offer practical opportunities for updating the industrial syngas-DMO-ethanol route.</div></div>","PeriodicalId":268,"journal":{"name":"Chem","volume":"10 11","pages":"Pages 3342-3363"},"PeriodicalIF":19.1,"publicationDate":"2024-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141578005","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-14DOI: 10.1016/j.chempr.2024.06.020
Pengfei Hu , Haosen Yang , Rutong Si , Bin Wei , Xiaotian Wang , Ziyan Xu , Xiuyi Yang , Tianqi Guo , Ralph Gebauer , Gilberto Teobaldi , Li-Min Liu , Zhongchang Wang , Lin Guo
Despite the exceptional properties and advanced functionalities of two-dimensional (2D) nanomaterials, the fabrication of freestanding, atomically thin metal nanosheets poses a considerable challenge due to the inherently omnidirectional nature of typical metallic bonds. Herein, we introduce a novel ligand-confinement strategy to prepare the atomically thin Ag nanosheets. The ultrathin 2D structure is stabilized by manipulating the coordinate ligands to construct confined spaces and lower the inherent high surface energy, thus avoiding agglomeration. The atomically thin 2D structure exhibits a distinct quantum confinement effect, inducing energy level splitting conducive to uniform hot spots on planar Ag surfaces and extraordinary surface-enhanced Raman spectroscopy (SERS) properties. Leveraging the synergistic effects of electromagnetic and chemical enhancement, our approach achieves single-molecule-level SERS detection at concentrations as low as 10−17 M of bisphenol F (BPF). The atomically thin noble metal-based SERS technology possesses superb merits of ultra-high sensitivity, extraordinary uniformity, and reproducibility.
尽管二维（2D）纳米材料具有非凡的特性和先进的功能，但由于典型金属键固有的全向性，独立的原子级薄金属纳米片的制备仍面临相当大的挑战。在此，我们介绍了一种制备原子级薄银纳米片的新型配体融合策略。通过操纵配位体构建密闭空间，降低固有的高表面能，从而避免团聚，稳定超薄二维结构。原子级薄二维结构表现出明显的量子约束效应，诱导能级分裂，有利于在平面银表面形成均匀的热点和非凡的表面增强拉曼光谱（SERS）特性。利用电磁和化学增强的协同效应，我们的方法实现了单分子级 SERS 检测，检测浓度低至 10-17 M 的双酚 F (BPF)。这种基于贵金属的原子超薄 SERS 技术具有超高灵敏度、超常均匀性和可重复性等优点。
{"title":"Atomically thin Ag nanosheets for single-molecule SERS detection of BPF","authors":"Pengfei Hu , Haosen Yang , Rutong Si , Bin Wei , Xiaotian Wang , Ziyan Xu , Xiuyi Yang , Tianqi Guo , Ralph Gebauer , Gilberto Teobaldi , Li-Min Liu , Zhongchang Wang , Lin Guo","doi":"10.1016/j.chempr.2024.06.020","DOIUrl":"10.1016/j.chempr.2024.06.020","url":null,"abstract":"<div><div><span>Despite the exceptional properties and advanced functionalities of two-dimensional (2D) nanomaterials<span><span>, the fabrication of freestanding, atomically thin metal nanosheets poses a considerable challenge due to the inherently omnidirectional nature of typical </span>metallic bonds<span><span>. Herein, we introduce a novel ligand-confinement strategy to prepare the atomically thin Ag nanosheets. The ultrathin 2D structure is stabilized by manipulating the coordinate ligands to construct confined spaces and lower the inherent high surface energy, thus avoiding agglomeration. The atomically thin 2D structure exhibits a distinct quantum confinement effect, inducing </span>energy level splitting<span><span> conducive to uniform hot spots on planar Ag surfaces and extraordinary surface-enhanced Raman spectroscopy (SERS) properties. Leveraging the synergistic effects of </span>electromagnetic and chemical enhancement, our approach achieves single-molecule-level SERS detection at concentrations as low as 10</span></span></span></span><sup>−17</sup><span> M of bisphenol F (BPF). The atomically thin noble metal-based SERS technology possesses superb merits of ultra-high sensitivity, extraordinary uniformity, and reproducibility.</span></div></div>","PeriodicalId":268,"journal":{"name":"Chem","volume":"10 11","pages":"Pages 3364-3373"},"PeriodicalIF":19.1,"publicationDate":"2024-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141578128","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-14DOI: 10.1016/j.chempr.2024.06.031
Wuchao Zhao , Fengchao Cui , Jianghua He , Yuetao Zhang , Eugene Y.-X. Chen
In metal-mediated stereoselective polymerization of cyclic esters, racemic catalysts use their enantiomers for enantioselective roles and achieve diverse polymer stereomicrostructures through intermolecular chain exchange. Here, an intramolecular chain shuttling mechanism is achieved by the combination of cis (R,S)-dithiourea and MeOK to overcome limitations on intermolecular polymer exchange and also offer diverse polymer stereomicrostructures. This system exhibits diastereospecificity toward the polymerization of both rac-lactide (rac-LA) and meso-LA, producing highly isotactic PLA (Pm ∼ 0.96) and heterotactic PLA (Pr ∼ 0.92), respectively. Mechanistic studies reveal an “oscillatory adaptive catalysis” (OAC) phenomenon, which is key to achieving dual recognition of the chirality of both the chain end and incoming monomer by using the two switchable chiral centers in catalyst. Such OAC enables dynamic interchange between chiral recognition (that triggers chain propagation) and stereochemical autocorrection (when monomer mismatched) by multi-site cooperativity, which induces chiral-site switching and polymer-chain shuttling intramolecularly within a single catalyst molecule.
{"title":"Oscillatory adaptive catalysis: Intramolecular chain shuttling regulated by stereo-autocorrection in stereoselective polymerization of lactide","authors":"Wuchao Zhao , Fengchao Cui , Jianghua He , Yuetao Zhang , Eugene Y.-X. Chen","doi":"10.1016/j.chempr.2024.06.031","DOIUrl":"10.1016/j.chempr.2024.06.031","url":null,"abstract":"<div><div><span>In metal-mediated stereoselective polymerization of cyclic esters, racemic catalysts use their enantiomers for enantioselective roles and achieve diverse polymer stereomicrostructures through intermolecular chain exchange. Here, an intramolecular chain shuttling mechanism is achieved by the combination of </span><em>cis</em> (<em>R,S</em>)-dithiourea and MeOK to overcome limitations on intermolecular polymer exchange and also offer diverse polymer stereomicrostructures. This system exhibits diastereospecificity toward the polymerization of both <em>rac</em>-lactide (<em>rac</em>-LA) and <em>meso</em>-LA, producing highly isotactic PLA (<em>P</em><sub>m</sub> ∼ 0.96) and heterotactic PLA (<em>P</em><sub>r</sub><span><span> ∼ 0.92), respectively. Mechanistic studies reveal an “oscillatory adaptive catalysis” (OAC) phenomenon, which is key to achieving dual recognition of the </span>chirality<span> of both the chain end and incoming monomer<span> by using the two switchable chiral centers in catalyst. Such OAC enables dynamic interchange between chiral recognition (that triggers chain propagation) and stereochemical autocorrection (when monomer mismatched) by multi-site cooperativity, which induces chiral-site switching and polymer-chain shuttling intramolecularly within a single catalyst molecule.</span></span></span></div></div>","PeriodicalId":268,"journal":{"name":"Chem","volume":"10 11","pages":"Pages 3396-3409"},"PeriodicalIF":19.1,"publicationDate":"2024-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141746612","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
By mimicking nanoscale galvanic reactions, this study focuses on optimizing catalytic hydrogenation by introducing two spatially separated sites for the activation of H2 into proton and electron pairs and the selective reduction of –NO2. The catalyst system is designed with the co-deposition of Pt and Fe2O3 nanoparticles on conductive carbon nanotubes, establishing an electron-transferring pathway. Protic solvents facilitate proton transport. Upon activation of H2 molecules into proton and electron pairs on Pt, modified with ammonia or amines, these active species are efficiently transferred to Fe2O3 nanoparticles for the selective reduction of –NO2 into amines without affecting other functional groups. Compared with Pt/CNT, which easily hydrogenates both C=C and –NO2 groups of 4-nitrostyrene, the Pt&Fe2O3/CNT catalyst modified by NH3 exhibits higher activity and selectivity for –NO2 hydrogenation. Electrochemically, Pt functions as the anode for the hydrogen oxidation reaction, while Fe2O3 acts as the cathode, selectively reducing –NO2.
{"title":"Selective hydrogenation catalysis enabled by nanoscale galvanic reactions","authors":"Mengfei Qiao , Qingyuan Wu , Ying Wang , Shanshan Gao , Ruixuan Qin , Shengjie Liu , Kehong Ding , Dongyuan Zhao , Nanfeng Zheng","doi":"10.1016/j.chempr.2024.06.030","DOIUrl":"10.1016/j.chempr.2024.06.030","url":null,"abstract":"<div><div><span>By mimicking nanoscale galvanic reactions, this study focuses on optimizing catalytic hydrogenation by introducing two spatially separated sites for the activation of H</span><sub>2</sub> into proton and electron pairs and the selective reduction of –NO<sub>2</sub>. The catalyst system is designed with the co-deposition of Pt and Fe<sub>2</sub>O<sub>3</sub><span><span> nanoparticles on conductive </span>carbon nanotubes<span>, establishing an electron-transferring pathway. Protic solvents facilitate proton transport. Upon activation of H</span></span><sub>2</sub> molecules into proton and electron pairs on Pt, modified with ammonia or amines, these active species are efficiently transferred to Fe<sub>2</sub>O<sub>3</sub><span> nanoparticles for the selective reduction of –NO</span><sub>2</sub> into amines without affecting other functional groups. Compared with Pt/CNT, which easily hydrogenates both C=C and –NO<sub>2</sub> groups of 4-nitrostyrene, the Pt&Fe<sub>2</sub>O<sub>3</sub>/CNT catalyst modified by NH<sub>3</sub> exhibits higher activity and selectivity for –NO<sub>2</sub><span> hydrogenation. Electrochemically, Pt functions as the anode for the hydrogen oxidation reaction, while Fe</span><sub>2</sub>O<sub>3</sub> acts as the cathode, selectively reducing –NO<sub>2</sub>.</div></div>","PeriodicalId":268,"journal":{"name":"Chem","volume":"10 11","pages":"Pages 3385-3395"},"PeriodicalIF":19.1,"publicationDate":"2024-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141754488","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-14DOI: 10.1016/j.chempr.2024.10.011
Edward J. Broker Jr. , Kathleen Floyd , James D. Batteas
In the current issue of Chem, Gugin et al. are showcasing the power of energy-dispersive X-ray diffraction to track kinetics and chemical phenomena in situ during twin screw extrusion. This technique holds great promise for industrial scale-up of green chemical syntheses.
在本期《化学》杂志上，Gugin 等人展示了能量色散 X 射线衍射在双螺杆挤压过程中现场跟踪动力学和化学现象的能力。这项技术为绿色化学合成的工业放大带来了巨大希望。
{"title":"In situ energy dispersive X-ray diffraction achieved in twin screw extrusion","authors":"Edward J. Broker Jr. , Kathleen Floyd , James D. Batteas","doi":"10.1016/j.chempr.2024.10.011","DOIUrl":"10.1016/j.chempr.2024.10.011","url":null,"abstract":"<div><div>In the current issue of <em>Chem</em>, Gugin et al. are showcasing the power of energy-dispersive X-ray diffraction to track kinetics and chemical phenomena <em>in situ</em> during twin screw extrusion. This technique holds great promise for industrial scale-up of green chemical syntheses.</div></div>","PeriodicalId":268,"journal":{"name":"Chem","volume":"10 11","pages":"Pages 3268-3270"},"PeriodicalIF":19.1,"publicationDate":"2024-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142562008","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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