Organic NIR-II dyes, particularly cyanine fluorophores, offer high molar extinction coefficients, biocompatibility and structural tunability and are popular for non-invasive, high-resolution and -contrast in vivo imaging. However, achieving stable, long-wavelength and large Stokes shift NIR-II cyanine suitable for NIR-IIa/IIb bioimaging is still a formidable challenge. Herein, we introduce a novel strategy that extends the emission wavelength by the enhanced HOMO-LUMO separation through simple donor ectopic substitution at the terminal structure of NIR-II cyanine. Compared to the original NIR-II cyanine Flav7, these novel dyes (NIR-ACs) exhibited a significant emission redshift and larger Stokes shift, with the maximum emission wavelength exceeding 1300 nm (NIR-IIa) and a tail emission exceeding 1500 nm (NIR-IIb). Notably, they also demonstrate excellent stability and deeper tissue imaging ability in vivo imaging. Finally, through surface modification of nanoparticles, NIR-ACs nanoparticles (NPs) have successfully achieved high-contrast tumor and bone-targeted detecting as well as multicolor imaging, providing robust tools for in-vivo diagnostics and biomedical research.
{"title":"Constructing Stable and Wavelength-Extended Heptamethine Cyanines via Donor Ectopic Substitution for NIR-IIa/b Bioimaging","authors":"Yi-Feng Ou, Hong-Ya Xiang, Xu Yang, Ren-Xuan Wang, Shuang-Yan Huan, Lin Yuan, Tian-Bing Ren, Xiao-Bing Zhang","doi":"10.1002/anie.202423978","DOIUrl":"https://doi.org/10.1002/anie.202423978","url":null,"abstract":"Organic NIR-II dyes, particularly cyanine fluorophores, offer high molar extinction coefficients, biocompatibility and structural tunability and are popular for non-invasive, high-resolution and -contrast in vivo imaging. However, achieving stable, long-wavelength and large Stokes shift NIR-II cyanine suitable for NIR-IIa/IIb bioimaging is still a formidable challenge. Herein, we introduce a novel strategy that extends the emission wavelength by the enhanced HOMO-LUMO separation through simple donor ectopic substitution at the terminal structure of NIR-II cyanine. Compared to the original NIR-II cyanine Flav7, these novel dyes (NIR-ACs) exhibited a significant emission redshift and larger Stokes shift, with the maximum emission wavelength exceeding 1300 nm (NIR-IIa) and a tail emission exceeding 1500 nm (NIR-IIb). Notably, they also demonstrate excellent stability and deeper tissue imaging ability in vivo imaging. Finally, through surface modification of nanoparticles, NIR-ACs nanoparticles (NPs) have successfully achieved high-contrast tumor and bone-targeted detecting as well as multicolor imaging, providing robust tools for in-vivo diagnostics and biomedical research.","PeriodicalId":125,"journal":{"name":"Angewandte Chemie International Edition","volume":"20 1","pages":""},"PeriodicalIF":16.6,"publicationDate":"2025-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143666571","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}
Here we report a photocatalytic method for the decarboxylative oxygenation of amino acid derivatives and short peptides using dioxygen as a green oxidant. A reverse catalytic strategy utilizing Lewis basic diphenyl diselenide as a Lewis acid catalyst to activate carboxylic acid via chalcogen bonding interaction is the key to this work. This synthetic method is tolerant of functionalities present in both natural and non‐proteinogenic amino acids, enabling the efficient synthesis of C‐terminal amides or imides. Mechanistic studies suggest there is a dual noncovalent interaction between diphenyl diselenide and carboxylic acid, which allows radical decarboxylation through photoinduced intermolecular electron transfer. This new activation mode of carboxylic acids will add a new dimension to classical decarboxylative reactions.
{"title":"Chalcogen‐Bonding‐Enabled, Light‐Driven Decarboxylative Oxygenation of Amino Acid Derivatives and Short Peptides using O2","authors":"Yuzheng Li, Taiqiang Ye, Feng Li, Shenpeng Tan","doi":"10.1002/anie.202502233","DOIUrl":"https://doi.org/10.1002/anie.202502233","url":null,"abstract":"Here we report a photocatalytic method for the decarboxylative oxygenation of amino acid derivatives and short peptides using dioxygen as a green oxidant. A reverse catalytic strategy utilizing Lewis basic diphenyl diselenide as a Lewis acid catalyst to activate carboxylic acid via chalcogen bonding interaction is the key to this work. This synthetic method is tolerant of functionalities present in both natural and non‐proteinogenic amino acids, enabling the efficient synthesis of C‐terminal amides or imides. Mechanistic studies suggest there is a dual noncovalent interaction between diphenyl diselenide and carboxylic acid, which allows radical decarboxylation through photoinduced intermolecular electron transfer. This new activation mode of carboxylic acids will add a new dimension to classical decarboxylative reactions.","PeriodicalId":125,"journal":{"name":"Angewandte Chemie International Edition","volume":"56 1","pages":""},"PeriodicalIF":16.6,"publicationDate":"2025-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143666039","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}
Potassium metal batteries with an anode‐less/‐free configuration could realize competitive energy density, which requires exceptional potassium plating/stripping reversibility via guiding smooth potassium growth and building mechanically stable solid electrolyte interphase (SEI). Electrolyte engineering has been the most widely adopted strategy, but there is less understanding of the electrode effect. We demonstrate that the extent of electrolyte decomposition could also be regulated through electrode surface modification. Elevating the work function of an Al current collector by coating a thin layer of Ni‐decorated carbon nanofiber could greatly suppress the copious solvent reduction, leading to the formation of inorganic‐rich SEIs. Such SEIs possess a large elastic deformation energy to accommodate the volume change and a high ionic conductivity to boost the reaction kinetics. Moreover, the potassiophilic nickel species offer abundant active sites to induce homogeneous potassium deposition. Benefiting from the synergy of stable interphases and promoted nucleation, the modified Al enables a 4.4 V anode‐free cell in a normal‐concentration electrolyte without anode precycling.
{"title":"Unraveling Electrode Surface Chemistry in Determining Interphase Stability and Deposition Homogeneity for Anode‐free Potassium Metal Batteries","authors":"Zhenlu Yu, Qun Liu, Danni Wang, Jie Shi, Dengyun Zhai, Biao Zhang","doi":"10.1002/anie.202502091","DOIUrl":"https://doi.org/10.1002/anie.202502091","url":null,"abstract":"Potassium metal batteries with an anode‐less/‐free configuration could realize competitive energy density, which requires exceptional potassium plating/stripping reversibility via guiding smooth potassium growth and building mechanically stable solid electrolyte interphase (SEI). Electrolyte engineering has been the most widely adopted strategy, but there is less understanding of the electrode effect. We demonstrate that the extent of electrolyte decomposition could also be regulated through electrode surface modification. Elevating the work function of an Al current collector by coating a thin layer of Ni‐decorated carbon nanofiber could greatly suppress the copious solvent reduction, leading to the formation of inorganic‐rich SEIs. Such SEIs possess a large elastic deformation energy to accommodate the volume change and a high ionic conductivity to boost the reaction kinetics. Moreover, the potassiophilic nickel species offer abundant active sites to induce homogeneous potassium deposition. Benefiting from the synergy of stable interphases and promoted nucleation, the modified Al enables a 4.4 V anode‐free cell in a normal‐concentration electrolyte without anode precycling.","PeriodicalId":125,"journal":{"name":"Angewandte Chemie International Edition","volume":"34 1","pages":""},"PeriodicalIF":16.6,"publicationDate":"2025-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143666194","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}
Wilhelm T.S. Huck, Thijs de Jong, Will Robinson, Astra Demertzi
It is generally accepted that minerals were an important source of prebiotic catalysis. In this work we demonstrate how the prebiotic sugar forming formose reaction is guided to unique reaction compositions in the presence of a variety of minerals. When the same mineral is transferred between multiple sequential batch reactions, a new reaction composition is obtained after each reaction cycle. We attribute this effect to the adsorption of catalytic Ca(OH)2 to mineral surfaces. Further exploration shows that first exposing the mineral surface to the aqueous catalyst allows the mineral to subsequently produce formose outputs without the need for any additional catalyst to be present. The impact of the minerals on the formose reaction is dependent on the previous environment. As such, the mineral surface functions as storage of the preceding environmental conditions. Our work supports the development of chemical complexity through the transfer of information between sequences of chemical environments.
{"title":"Environmental History is Transferred via Minerals Altering Formose Reaction Pathways","authors":"Wilhelm T.S. Huck, Thijs de Jong, Will Robinson, Astra Demertzi","doi":"10.1002/anie.202504659","DOIUrl":"https://doi.org/10.1002/anie.202504659","url":null,"abstract":"It is generally accepted that minerals were an important source of prebiotic catalysis. In this work we demonstrate how the prebiotic sugar forming formose reaction is guided to unique reaction compositions in the presence of a variety of minerals. When the same mineral is transferred between multiple sequential batch reactions, a new reaction composition is obtained after each reaction cycle. We attribute this effect to the adsorption of catalytic Ca(OH)2 to mineral surfaces. Further exploration shows that first exposing the mineral surface to the aqueous catalyst allows the mineral to subsequently produce formose outputs without the need for any additional catalyst to be present. The impact of the minerals on the formose reaction is dependent on the previous environment. As such, the mineral surface functions as storage of the preceding environmental conditions. Our work supports the development of chemical complexity through the transfer of information between sequences of chemical environments.","PeriodicalId":125,"journal":{"name":"Angewandte Chemie International Edition","volume":"17 1","pages":""},"PeriodicalIF":16.6,"publicationDate":"2025-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143666353","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}
Songbo Ye, Fangzhou Liu, Fangxin She, Jiaxiang Chen, Di Zhang, Akichika Kumatani, Hitoshi Shiku, Li Wei, Hao Li
The design principles for metal-nitrogen-carbon (M-N-C) single-atom catalysts (SACs) in the hydrogen evolution reaction (HER) have been extensively studied. While hydrogen binding energy ([[EQUATION]]) has long been used as a HER descriptor during the past decades, its applicability to HER SACs has been met with significant controversy. Herein, we investigate the effects of HO*/O* poisoning and H* coverage on SACs with varied metal centers and coordination environments using pH-dependent surface Pourbaix diagrams at the reversible hydrogen electrode (RHE) scale and microkinetic modeling. Our findings reveal that HO* poisoning, realistic H* adsorption strengths at active metal sites, and the potential HER activity at the coordinating N-sites are crucial factors that should be considered for accurate descriptor development. Experimental validation using a series of M-phthalocyanine/CNT catalysts confirms the theoretical predictions, with excellent agreement in exchange current densities and the role of N-sites in Ni/Cu-phthalocyanine/CNT catalysts. More importantly, the controversy surrounding HER SAC design principles is resolved through a novel 2D microkinetic volcano model that incorporates active sites, H* coverage, and HO* poisoning. This work provides answers to a long-lasting debate on HER descriptors by establishing [[EQUATION]] and [[EQUATION]] as a combined HER descriptor for SACs, offering new guidelines for catalyst design.
{"title":"Hydrogen Binding Energy Is Insufficient for Describing Hydrogen Evolution on Single-Atom Catalysts","authors":"Songbo Ye, Fangzhou Liu, Fangxin She, Jiaxiang Chen, Di Zhang, Akichika Kumatani, Hitoshi Shiku, Li Wei, Hao Li","doi":"10.1002/anie.202425402","DOIUrl":"https://doi.org/10.1002/anie.202425402","url":null,"abstract":"The design principles for metal-nitrogen-carbon (M-N-C) single-atom catalysts (SACs) in the hydrogen evolution reaction (HER) have been extensively studied. While hydrogen binding energy ([[EQUATION]]) has long been used as a HER descriptor during the past decades, its applicability to HER SACs has been met with significant controversy. Herein, we investigate the effects of HO*/O* poisoning and H* coverage on SACs with varied metal centers and coordination environments using pH-dependent surface Pourbaix diagrams at the reversible hydrogen electrode (RHE) scale and microkinetic modeling. Our findings reveal that HO* poisoning, realistic H* adsorption strengths at active metal sites, and the potential HER activity at the coordinating N-sites are crucial factors that should be considered for accurate descriptor development. Experimental validation using a series of M-phthalocyanine/CNT catalysts confirms the theoretical predictions, with excellent agreement in exchange current densities and the role of N-sites in Ni/Cu-phthalocyanine/CNT catalysts. More importantly, the controversy surrounding HER SAC design principles is resolved through a novel 2D microkinetic volcano model that incorporates active sites, H* coverage, and HO* poisoning. This work provides answers to a long-lasting debate on HER descriptors by establishing [[EQUATION]] and [[EQUATION]] as a combined HER descriptor for SACs, offering new guidelines for catalyst design.","PeriodicalId":125,"journal":{"name":"Angewandte Chemie International Edition","volume":"54 6 1","pages":""},"PeriodicalIF":16.6,"publicationDate":"2025-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143660760","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}
Natalie Hanheiser, Yuhang Jiang, Christian Zoister, Mathias Dimde, Katharina Achazi, Chuanxiong Nie, Yuanyuan Li, Rainer Haag, Abhishek Kumar Singh
Bacterial infections and antibiotic resistance present an ever-increasing threat to human health worldwide, and medicine urgently needs new alternatives for the successful treatment of bacterial infections. Cationic surfactants have proven to be effective antibacterial agents due to their ability to disrupt bacterial membranes, inhibit biofilm formation, and combat a broad spectrum of pathogens. We employed a orthogonal click chemistry strategy for the efficient modular synthesis of six novel cationic surfactants. Our results emphasize the strong correlation between the surfactant design and its antibacterial potential. Among these six cationic surfactants we identified a prime candidate, which possessed an impressive antibacterial effect against gram-positive and gram-negative bacteria, including drug-resistant strains. We found that our surfactant can prevent biofilm formation and eradicate already existing biofilms. Cryo-TEM imaging was used to reveal the membrane-disrupting properties of the surfactant. In-vivo wound healing experiments underline the surfactants’ ability to inhibit wound infections. Cationic surfactants often face the challenge of balancing strong antibacterial activity with minimal cytotoxicity. Our strategic design and orthogonal click chemistry approach have enabled precise fine-tuning of molecular structures to achieve an optimal balance between antibacterial efficacy and biocompatibility, effectively overcoming this critical limitation.
{"title":"Modular Synthesis of Dendritic Oligo-Glycerol Cationic Surfactants for Enhanced Antibacterial Efficacy","authors":"Natalie Hanheiser, Yuhang Jiang, Christian Zoister, Mathias Dimde, Katharina Achazi, Chuanxiong Nie, Yuanyuan Li, Rainer Haag, Abhishek Kumar Singh","doi":"10.1002/anie.202425069","DOIUrl":"https://doi.org/10.1002/anie.202425069","url":null,"abstract":"Bacterial infections and antibiotic resistance present an ever-increasing threat to human health worldwide, and medicine urgently needs new alternatives for the successful treatment of bacterial infections. Cationic surfactants have proven to be effective antibacterial agents due to their ability to disrupt bacterial membranes, inhibit biofilm formation, and combat a broad spectrum of pathogens. We employed a orthogonal click chemistry strategy for the efficient modular synthesis of six novel cationic surfactants. Our results emphasize the strong correlation between the surfactant design and its antibacterial potential. Among these six cationic surfactants we identified a prime candidate, which possessed an impressive antibacterial effect against gram-positive and gram-negative bacteria, including drug-resistant strains. We found that our surfactant can prevent biofilm formation and eradicate already existing biofilms. Cryo-TEM imaging was used to reveal the membrane-disrupting properties of the surfactant. In-vivo wound healing experiments underline the surfactants’ ability to inhibit wound infections. Cationic surfactants often face the challenge of balancing strong antibacterial activity with minimal cytotoxicity. Our strategic design and orthogonal click chemistry approach have enabled precise fine-tuning of molecular structures to achieve an optimal balance between antibacterial efficacy and biocompatibility, effectively overcoming this critical limitation.","PeriodicalId":125,"journal":{"name":"Angewandte Chemie International Edition","volume":"21 1","pages":""},"PeriodicalIF":16.6,"publicationDate":"2025-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143660753","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}
Timothy P. Aldhous, Raymond Chung, Abbas Hassan, Andrew G. Dalling, Phillippa Cooper, Simon Grélaud, Richard J. Mudd, Lyman J. Feron, Paul D. Kemmitt, John Bower
Ir-systems modified with ferrocene-based homochiral diphosphonite ligands, prepared from functionalized SPINOL derivatives, promote benzamide-directed hydroarylative cross-couplings involving minimally activated alkenes. The processes are highly branched selective and enantioselective. Accordingly, tertiary benzylic stereocenters are generated under byproduct free conditions. This contrasts conventional cross-coupling approaches, which are less step and atom economical. Preliminary results show that the process extends to the formation of quaternary benzylic stereocenters.
{"title":"Benzamide-Directed Hydroarylative Cross-Couplings Using Minimally Activated Alkenes: Enantioselective Synthesis of Tertiary and Quaternary Stereocenters","authors":"Timothy P. Aldhous, Raymond Chung, Abbas Hassan, Andrew G. Dalling, Phillippa Cooper, Simon Grélaud, Richard J. Mudd, Lyman J. Feron, Paul D. Kemmitt, John Bower","doi":"10.1002/anie.202502569","DOIUrl":"https://doi.org/10.1002/anie.202502569","url":null,"abstract":"Ir-systems modified with ferrocene-based homochiral diphosphonite ligands, prepared from functionalized SPINOL derivatives, promote benzamide-directed hydroarylative cross-couplings involving minimally activated alkenes. The processes are highly branched selective and enantioselective. Accordingly, tertiary benzylic stereocenters are generated under byproduct free conditions. This contrasts conventional cross-coupling approaches, which are less step and atom economical. Preliminary results show that the process extends to the formation of quaternary benzylic stereocenters.","PeriodicalId":125,"journal":{"name":"Angewandte Chemie International Edition","volume":"44 1","pages":""},"PeriodicalIF":16.6,"publicationDate":"2025-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143660756","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}
Lithium (Li) metal exhibits great potential for achieving high-energy-density rechargeable batteries. However, the practical application of Li metal anodes is severely hindered by the uncontrollable growth of lithium dendrites as well as the instability of the spontaneously generated solid electrolyte interphase (SEI), causing safety concerns and lifespan issues. Herein, we customize a novel urea-linked covalent organic framework (COF-531) as an interfacial Li-ion pump. The COF-531 is constructed utilizing a highly dynamic urea-linkage, which balances the low reactivity of N-rich melamine (MA), and could simultaneously provide abundant lithiophilic N sites and crystallinity ordered ion channels. This structure is able to promote efficient Li+ de-solvation and transport, leading to uniform deposition via inhibiting dendrites growth. As a result, the COF@Li anode exhibits remarkable cycling performance under high current density (10 mA cm-2 over 11500 h and 20 mA cm-2 over 6000 h in the symmetric Li cells, and 1013 mAh g-1 after 500 cycles under 8.4 A g-1 in a COF@Li || S-in-CMK-3 cell), setting a new benchmark for long-cycle performance in carbonate-based electrolyte. Remarkably, the COF-531 can be produced at a low-cost (~58.6 USD kg-1) on a kilogram scale. This work addresses a critical bottleneck in the commercialization of Li-metal batteries.
{"title":"Urea-linked Covalent Organic Framework as a Li-ion Guided Channel Enabling Ultra-Stable Lithium Metal Anode in Carbonate-based Electrolyte","authors":"Fu-Sheng Ke, Caihong Zhang, Zhen Luo, Kean Chen, Chunxing Yan, Lezhi Yi, Chengtao Gong, Yuliang Cao","doi":"10.1002/anie.202500314","DOIUrl":"https://doi.org/10.1002/anie.202500314","url":null,"abstract":"Lithium (Li) metal exhibits great potential for achieving high-energy-density rechargeable batteries. However, the practical application of Li metal anodes is severely hindered by the uncontrollable growth of lithium dendrites as well as the instability of the spontaneously generated solid electrolyte interphase (SEI), causing safety concerns and lifespan issues. Herein, we customize a novel urea-linked covalent organic framework (COF-531) as an interfacial Li-ion pump. The COF-531 is constructed utilizing a highly dynamic urea-linkage, which balances the low reactivity of N-rich melamine (MA), and could simultaneously provide abundant lithiophilic N sites and crystallinity ordered ion channels. This structure is able to promote efficient Li+ de-solvation and transport, leading to uniform deposition via inhibiting dendrites growth. As a result, the COF@Li anode exhibits remarkable cycling performance under high current density (10 mA cm-2 over 11500 h and 20 mA cm-2 over 6000 h in the symmetric Li cells, and 1013 mAh g-1 after 500 cycles under 8.4 A g-1 in a COF@Li || S-in-CMK-3 cell), setting a new benchmark for long-cycle performance in carbonate-based electrolyte. Remarkably, the COF-531 can be produced at a low-cost (~58.6 USD kg-1) on a kilogram scale. This work addresses a critical bottleneck in the commercialization of Li-metal batteries.","PeriodicalId":125,"journal":{"name":"Angewandte Chemie International Edition","volume":"90 1","pages":""},"PeriodicalIF":16.6,"publicationDate":"2025-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143660761","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}
Zhi-You Zhou, Jia-Feng Du, Jin-Yu Ye, Chao Yang, Chun-Yu Qiu, Nan Fang, Yu-Cheng Wang, Shi-Gang Sun
CO poisoning remains a critical challenge for proton exchange membrane fuel cells (PEMFCs). Current studies of CO tolerance primarily focus on solid/liquid interfaces (in-situ conditions), which differ significantly from PEMFCs' solid/liquid/gas triple-phase interfaces (operando conditions) in microenvironment and mass transport. Herein, we developed an operando transmission infrared spectroscopy method that enables direct observation of CO tolerance mechanism on commercial PtRu/C catalysts in PEMFCs. Under in-situ conditions, hydrogen oxidation reaction (HOR) activity is governed by CO mass transfer, and is insensitive to the availability of active sites, while it is highly sensitive under operando conditions due to enhanced mass transfer, thereby aggravating CO poisoning effects. Notably, 76% of HOR activity can recover upon switching to pure H2. Based on CO band evolution, we proposed a new pathway beyond the traditional bifunctional mechanism of CO tolerance: CO migrates from Pt to Ru sites, undergoing oxidation at potentials as low as 0.01 V vs. reversible hydrogen electrode (RHE).
{"title":"Unraveling CO-Tolerance Mechanism in Proton Exchange Membrane Fuel Cells via Operando Infrared Spectroscopy","authors":"Zhi-You Zhou, Jia-Feng Du, Jin-Yu Ye, Chao Yang, Chun-Yu Qiu, Nan Fang, Yu-Cheng Wang, Shi-Gang Sun","doi":"10.1002/anie.202503868","DOIUrl":"https://doi.org/10.1002/anie.202503868","url":null,"abstract":"CO poisoning remains a critical challenge for proton exchange membrane fuel cells (PEMFCs). Current studies of CO tolerance primarily focus on solid/liquid interfaces (in-situ conditions), which differ significantly from PEMFCs' solid/liquid/gas triple-phase interfaces (operando conditions) in microenvironment and mass transport. Herein, we developed an operando transmission infrared spectroscopy method that enables direct observation of CO tolerance mechanism on commercial PtRu/C catalysts in PEMFCs. Under in-situ conditions, hydrogen oxidation reaction (HOR) activity is governed by CO mass transfer, and is insensitive to the availability of active sites, while it is highly sensitive under operando conditions due to enhanced mass transfer, thereby aggravating CO poisoning effects. Notably, 76% of HOR activity can recover upon switching to pure H2. Based on CO band evolution, we proposed a new pathway beyond the traditional bifunctional mechanism of CO tolerance: CO migrates from Pt to Ru sites, undergoing oxidation at potentials as low as 0.01 V vs. reversible hydrogen electrode (RHE).","PeriodicalId":125,"journal":{"name":"Angewandte Chemie International Edition","volume":"70 1","pages":""},"PeriodicalIF":16.6,"publicationDate":"2025-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143660792","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}
Hua-Hong Chen, Jia-Tian Jiang, Ye-Nan Yang, Long-Wu Ye, Bo Zhou
Carboxylic acids are readily available chemicals with broad applications in chemistry-related areas, and their coupling with amines and alcohols is a fundamental transformation in organic synthesis. However, the catalytic enantioselective coupling of carboxylic acids remains elusive, especially for the atroposelective reaction. Here we report a chiral Brønsted acid (CBA)-catalyzed atroposelective coupling of carboxylic acids with amines and alcohols using ynamides as coupling reagents. The novel enantiocontrol involving CBA-catalyzed ester addition enables the straightforward construction of axially chiral amides and planar-chiral esters with high enantioselectivities through atroposelective intermolecular amidation and intramolecular macrolactonization. Diverse medicinally relevant carboxylic acids can undergo direct late-stage modification by this method. Importantly, this reaction represents the first atroposelective coupling of carboxylic acids with amines, as well as the first chemocatalytic atroposelective coupling of carboxylic acids with alcohols. The resulting atropisomeric skeletons can be readily derivatized to chiral ligands and catalysts for asymmetric catalysis.
{"title":"Brønsted Acid-Catalyzed Atroposelective Coupling of Carboxylic Acids with Amines and Alcohols via Ynamide Mediation","authors":"Hua-Hong Chen, Jia-Tian Jiang, Ye-Nan Yang, Long-Wu Ye, Bo Zhou","doi":"10.1002/anie.202505167","DOIUrl":"https://doi.org/10.1002/anie.202505167","url":null,"abstract":"Carboxylic acids are readily available chemicals with broad applications in chemistry-related areas, and their coupling with amines and alcohols is a fundamental transformation in organic synthesis. However, the catalytic enantioselective coupling of carboxylic acids remains elusive, especially for the atroposelective reaction. Here we report a chiral Brønsted acid (CBA)-catalyzed atroposelective coupling of carboxylic acids with amines and alcohols using ynamides as coupling reagents. The novel enantiocontrol involving CBA-catalyzed ester addition enables the straightforward construction of axially chiral amides and planar-chiral esters with high enantioselectivities through atroposelective intermolecular amidation and intramolecular macrolactonization. Diverse medicinally relevant carboxylic acids can undergo direct late-stage modification by this method. Importantly, this reaction represents the first atroposelective coupling of carboxylic acids with amines, as well as the first chemocatalytic atroposelective coupling of carboxylic acids with alcohols. The resulting atropisomeric skeletons can be readily derivatized to chiral ligands and catalysts for asymmetric catalysis.","PeriodicalId":125,"journal":{"name":"Angewandte Chemie International Edition","volume":"37 1","pages":""},"PeriodicalIF":16.6,"publicationDate":"2025-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143660751","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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