Hydroxylamine (NH2OH) has a broad range of applications. Electrocatalytic semireduction of nitrate (NO3-) to NH2OH is a promising pathway for its sustainable production. However, the reported route typically led to either insufficient or excessive hydrogenation because the mismatch between supply and demand of active species during electrocatalysis remains a critical challenge, resulting in poor selectivity to NH2OH. Herein, we demonstrate an interfacial water (H2O) frustration strategy to achieve highly selective electrocatalytic semireduction of nitrate (NO3-) to hydroxylamine (NH2OH). By engineering the electric double layer (EDL) through alkali metal cation modulation, we precisely regulated the activation of interfacial H2O to inhibit excessive active hydrogen (*H) generation, thereby controlling the *H supply. In addition, tensile-strained bibased catalysts promoted *NO intermediate formation, enhancing *H demand and suppressing over-reduction to NH3. It achieved a Faradaic efficiency (FE) of 93.9% for NH2OH at 120 mA cm-2 under acidic conditions, which enabled the gram-scale synthesis of industrially relevant oximes with high nitrogen selectivity. Remarkably, this work achieved the highest NH2OH FE under industrial-level current densities (>100 mA cm-2). This work provided a generalizable approach for steering semireduction pathways through interfacial H2O frustration, which constructs the supply-demand balance of essential active species involved in electrocatalytic reactions.
羟胺（NH2OH）具有广泛的应用。硝酸（NO3-）电催化半还原制NH2OH是一条很有前途的可持续生产途径。然而，报道的途径通常导致氢化不足或过度，因为电催化过程中活性物质的供需不匹配仍然是一个关键挑战，导致对NH2OH的选择性差。在此，我们展示了一种界面水（H2O）挫折策略，以实现高选择性电催化硝酸（NO3-）半还原为羟胺（NH2OH）。通过碱金属阳离子调制工程双电层（EDL），精确调节界面H2O的活化，抑制过量活性氢（*H）的产生，从而控制*H的供给。此外，拉伸应变双基催化剂促进了*NO中间体的形成，增加了*H需求，抑制了对NH3的过度还原。在酸性条件下，在120 mA cm-2的条件下，NH2OH的法拉第效率（FE）达到93.9%，实现了克级合成具有高氮选择性的工业相关肟。值得注意的是，这项工作在工业级电流密度（bbb100 mA cm-2）下实现了最高的NH2OH FE。这项工作为通过界面水受挫控制半还原途径提供了一种可推广的方法，该方法构建了参与电催化反应的必需活性物质的供需平衡。
{"title":"Interfacial Water Frustration for Nitrate Semireduction to Hydroxylamine at Industrial-Relevant Currents.","authors":"Shunhan Jia,Ruhan Wang,Weixiang Li,Chaofeng Zheng,Xinning Song,Hanle Liu,Libing Zhang,Limin Wu,Xingxing Tan,Xiaodong Ma,Baolong Qu,Rongjuan Feng,Qian Li,Qinglei Meng,Lihong Jing,Lei He,Xiaofu Sun,Buxing Han","doi":"10.1021/jacs.5c19205","DOIUrl":"https://doi.org/10.1021/jacs.5c19205","url":null,"abstract":"Hydroxylamine (NH2OH) has a broad range of applications. Electrocatalytic semireduction of nitrate (NO3-) to NH2OH is a promising pathway for its sustainable production. However, the reported route typically led to either insufficient or excessive hydrogenation because the mismatch between supply and demand of active species during electrocatalysis remains a critical challenge, resulting in poor selectivity to NH2OH. Herein, we demonstrate an interfacial water (H2O) frustration strategy to achieve highly selective electrocatalytic semireduction of nitrate (NO3-) to hydroxylamine (NH2OH). By engineering the electric double layer (EDL) through alkali metal cation modulation, we precisely regulated the activation of interfacial H2O to inhibit excessive active hydrogen (*H) generation, thereby controlling the *H supply. In addition, tensile-strained bibased catalysts promoted *NO intermediate formation, enhancing *H demand and suppressing over-reduction to NH3. It achieved a Faradaic efficiency (FE) of 93.9% for NH2OH at 120 mA cm-2 under acidic conditions, which enabled the gram-scale synthesis of industrially relevant oximes with high nitrogen selectivity. Remarkably, this work achieved the highest NH2OH FE under industrial-level current densities (>100 mA cm-2). This work provided a generalizable approach for steering semireduction pathways through interfacial H2O frustration, which constructs the supply-demand balance of essential active species involved in electrocatalytic reactions.","PeriodicalId":49,"journal":{"name":"Journal of the American Chemical Society","volume":"29 1","pages":""},"PeriodicalIF":15.0,"publicationDate":"2025-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145704678","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}
Ying Lu, Luhan Wei, Yang Hu, Zihan Xu, Haowen Chen, Nian Zhang, Qiyang Lu
Metal exsolution from perovskite oxides is a promising strategy for fabricating durable catalysts of uniformly dispersed nanoparticles that are anchored to an oxide matrix. However, recent studies have shown that exsolved nanoparticles may still undergo coarsening over extended operating periods, posing challenges for long-term stability. In this work, we show that the strength of the metal–support interaction (MSI) between exsolved metal nanoparticles and the oxide matrix, tuned by the oxygen chemical potential, governs the dominant coarsening pathways of exsolved nanoparticles. We found a volcano-like relationship between MSI strength and the coarsening or growth rate of nanoparticles subjected to long-time annealing. We further reveal that weak MSI induced by a high surface oxygen vacancy concentration can accelerate particle migration and coalescence, while strong MSI led by a higher oxygen chemical potential favors Ostwald ripening, while both can cause instability of exsolved nanoparticles. These insights can inform the design of durable nanocatalysts by offering a mechanistic understanding of particle growth in metal exsolution.
{"title":"Metal–Support Interaction Tuned by Oxygen Chemical Potential Governs Coarsening of Metal Nanoparticles Exsolved from Perovskite Oxides","authors":"Ying Lu, Luhan Wei, Yang Hu, Zihan Xu, Haowen Chen, Nian Zhang, Qiyang Lu","doi":"10.1021/jacs.5c13118","DOIUrl":"https://doi.org/10.1021/jacs.5c13118","url":null,"abstract":"Metal exsolution from perovskite oxides is a promising strategy for fabricating durable catalysts of uniformly dispersed nanoparticles that are anchored to an oxide matrix. However, recent studies have shown that exsolved nanoparticles may still undergo coarsening over extended operating periods, posing challenges for long-term stability. In this work, we show that the strength of the metal–support interaction (MSI) between exsolved metal nanoparticles and the oxide matrix, tuned by the oxygen chemical potential, governs the dominant coarsening pathways of exsolved nanoparticles. We found a volcano-like relationship between MSI strength and the coarsening or growth rate of nanoparticles subjected to long-time annealing. We further reveal that weak MSI induced by a high surface oxygen vacancy concentration can accelerate particle migration and coalescence, while strong MSI led by a higher oxygen chemical potential favors Ostwald ripening, while both can cause instability of exsolved nanoparticles. These insights can inform the design of durable nanocatalysts by offering a mechanistic understanding of particle growth in metal exsolution.","PeriodicalId":49,"journal":{"name":"Journal of the American Chemical Society","volume":"114 4 1","pages":""},"PeriodicalIF":15.0,"publicationDate":"2025-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145704836","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}
Anthony Dougman Cho, Agata Wawrzkiewicz-Jałowiecka, Claudia E.P. Dewi, Shiwei Tang, DaVante Cain, Ethan Cao, Craig Martens, Tilman E. Schäffer, Javier Cervera, Patricio Ramirez, Salvador Mafe, Zuzanna S. Siwy
Nanopores provide controlled nanoconfinement that can be used to induce localized chemical reactions. Here, we present a nanopore exhibiting memory in the frequency of ion current oscillations induced by the dynamic formation and removal of nanoprecipitates within the pore volume. We find that the onset and characteristics of these current oscillations depend on the direction of the voltage scan, with memory effects evidenced in the frequency of switching between high and low conductance states and the probability of the pore to be in the open state. We have also emulated conductive synaptic switching behavior by applying voltage pulses and demonstrated an ability for the system to exhibit long-term potentiation (LTP) and long-term depression (LTD) that mimic learning and memory of synapses. A hypothesis is presented stating that the memory effects arise from the delayed formation and clearing of nanoprecipitates due to spatial-temporal asymmetry as well as from long-term variations in the effective surface charge. We propose a model in which precipitate formation is limited by the cation arrival rate. Our delayed logistic expression successfully recreates steady-state and oscillatory features in the transmembrane current. Nanopores with memory encoded in the frequency of ion current oscillations emulate how the brain stores information, open the possibility to achieve high-dimensional ionic memory, and move beyond the hysteresis in average conductance of ionic memristors.
{"title":"Nanopores with Ionic Memory in Oscillating Ion Current Signals","authors":"Anthony Dougman Cho, Agata Wawrzkiewicz-Jałowiecka, Claudia E.P. Dewi, Shiwei Tang, DaVante Cain, Ethan Cao, Craig Martens, Tilman E. Schäffer, Javier Cervera, Patricio Ramirez, Salvador Mafe, Zuzanna S. Siwy","doi":"10.1021/jacs.5c16779","DOIUrl":"https://doi.org/10.1021/jacs.5c16779","url":null,"abstract":"Nanopores provide controlled nanoconfinement that can be used to induce localized chemical reactions. Here, we present a nanopore exhibiting memory in the frequency of ion current oscillations induced by the dynamic formation and removal of nanoprecipitates within the pore volume. We find that the onset and characteristics of these current oscillations depend on the direction of the voltage scan, with memory effects evidenced in the frequency of switching between high and low conductance states and the probability of the pore to be in the open state. We have also emulated conductive synaptic switching behavior by applying voltage pulses and demonstrated an ability for the system to exhibit long-term potentiation (LTP) and long-term depression (LTD) that mimic learning and memory of synapses. A hypothesis is presented stating that the memory effects arise from the delayed formation and clearing of nanoprecipitates due to spatial-temporal asymmetry as well as from long-term variations in the effective surface charge. We propose a model in which precipitate formation is limited by the cation arrival rate. Our delayed logistic expression successfully recreates steady-state and oscillatory features in the transmembrane current. Nanopores with memory encoded in the frequency of ion current oscillations emulate how the brain stores information, open the possibility to achieve high-dimensional ionic memory, and move beyond the hysteresis in average conductance of ionic memristors.","PeriodicalId":49,"journal":{"name":"Journal of the American Chemical Society","volume":"35 1","pages":""},"PeriodicalIF":15.0,"publicationDate":"2025-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145704838","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}
Yu Wang, Liwen Liu, Qingyun Zheng, Yincui Wu, Zhen Su, Rujing Yuan, Qiong Xia, Beichen Wang, Yuanyuan Yu, Yi-Ming Li
Dynamically profiling of interactors of polyubiquitin (polyUb) chain topologies facilitates deciphering their functional specificity. Current strategies employing antibodies, synthetic antigen-binding fragments (sABs), or ″Affimers″ often lack temporal resolution and face challenges in detecting interactors of low-abundance polyUb chains, such as linear Ub (<0.2% of total Ub chains). Here, we structure-guided designed a photoactivatable OTULIN-specific inhibitor, linear-diUbp-Glu16(4-methoxy-7-nitroindoline, MNI)-dehydroalanine (Dha), which enables transient inhibition of this exclusively linear-specific deubiquitinase in living cells, thereby inducing rapid accumulation of linear Ub chains. Based on this tool, we developed a new strategy of synergizing the linear-diUbp-Glu16(MNI)-Dha with a biotinylated linear-antigen-binding fragment (Fab), which facilitated time-resolved profiling of linear polyubiquitination interactors in both TNF-α stimulated HeLa cells and macrophage colony-stimulating factor (M-CSF)-induced bone-marrow-derived macrophages. Our work also provides new opportunities for analyzing interactors of other low-abundance Ub chains, especially in hard-to-transfect cells, and highlights the effectiveness of chemical protein synthesis in developing advanced protein tools for biological discovery.
{"title":"Synergizing Structure-Guided Photocaged Linear Diubiquitin-Dha with Biotinylated Linear-Fab for Time-Resolved Profiling of Interactors in Living Cells","authors":"Yu Wang, Liwen Liu, Qingyun Zheng, Yincui Wu, Zhen Su, Rujing Yuan, Qiong Xia, Beichen Wang, Yuanyuan Yu, Yi-Ming Li","doi":"10.1021/jacs.5c15159","DOIUrl":"https://doi.org/10.1021/jacs.5c15159","url":null,"abstract":"Dynamically profiling of interactors of polyubiquitin (polyUb) chain topologies facilitates deciphering their functional specificity. Current strategies employing antibodies, synthetic antigen-binding fragments (sABs), or ″Affimers″ often lack temporal resolution and face challenges in detecting interactors of low-abundance polyUb chains, such as linear Ub (<0.2% of total Ub chains). Here, we structure-guided designed a photoactivatable OTULIN-specific inhibitor, linear-diUb<sub>p-Glu16(4-methoxy-7-nitroindoline, MNI)</sub>-dehydroalanine (Dha), which enables transient inhibition of this exclusively linear-specific deubiquitinase in living cells, thereby inducing rapid accumulation of linear Ub chains. Based on this tool, we developed a new strategy of synergizing the linear-diUb<sub>p-Glu16(MNI)</sub>-Dha with a biotinylated linear-antigen-binding fragment (Fab), which facilitated time-resolved profiling of linear polyubiquitination interactors in both TNF-α stimulated HeLa cells and macrophage colony-stimulating factor (M-CSF)-induced bone-marrow-derived macrophages. Our work also provides new opportunities for analyzing interactors of other low-abundance Ub chains, especially in hard-to-transfect cells, and highlights the effectiveness of chemical protein synthesis in developing advanced protein tools for biological discovery.","PeriodicalId":49,"journal":{"name":"Journal of the American Chemical Society","volume":"29 1","pages":""},"PeriodicalIF":15.0,"publicationDate":"2025-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145711433","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}
Controllable synthesis of monodisperse porous metal oxide semiconductor (MOS) nanospheres with uniform size and a tailored chemical environment is highly desired in the compatible manufacturing of high-performance nanodevices. However, the lack of an effective synthesis method has been a crucial challenge due to the uncontrollable hydrolysis rate of precursors and insufficient coassembly driving force. Herein, an active colloidal polymer-directing method is proposed for the facile synthesis of uniform functionalized mesoporous MOS nanospheres, such as mesoporous SnO2 nanospheres with different single-atom modifications (SA/mSnO2). This synthesis method features the utilization of single-atom-modified mesoporous polydopamine nanospheres as the intermediate, whose phenolic hydroxyl and imine groups enable the formation of the SnO2 skeleton and stabilization of SA, respectively. A library of stable gas-sensing inks is prepared based on the obtained SA/mSnO2 nanospheres, enabling wafer-scale fabrication of sensing layers on microelectromechanical systems chips through high-speed printing. These as-fabricated SA/mSnO2 sensors exhibit tailored selectivity due to different single-atom modifications, high sensitivity (5.6 times higher than that of commercial sensors), and excellent device-to-device consistency. Furthermore, by integrating different SA/mSnO2 nanodevices into sensor arrays, an advanced intelligent olfactory system is produced and further integrated into an automated guided vehicle, enabling the autonomous identification and transport of low-concentration leaked chemicals.
{"title":"Active Polymer-Templated Porous Metal Oxide Nanospheres with Tailored Single-Atom Modification for Olfactory Intelligence","authors":"Keyu Chen, Liyuan Zhu, Jianwu Wang, Wenhe Xie, Yu Deng, Lingxiao Xue, Huan Long, Huiming Wan, Jing Ren, Kaiping Yuan, Wei Wang, Qunyan Yao, Dongyuan Zhao, Xiaodong Chen, Yonghui Deng","doi":"10.1021/jacs.5c16614","DOIUrl":"https://doi.org/10.1021/jacs.5c16614","url":null,"abstract":"Controllable synthesis of monodisperse porous metal oxide semiconductor (MOS) nanospheres with uniform size and a tailored chemical environment is highly desired in the compatible manufacturing of high-performance nanodevices. However, the lack of an effective synthesis method has been a crucial challenge due to the uncontrollable hydrolysis rate of precursors and insufficient coassembly driving force. Herein, an active colloidal polymer-directing method is proposed for the facile synthesis of uniform functionalized mesoporous MOS nanospheres, such as mesoporous SnO<sub>2</sub> nanospheres with different single-atom modifications (SA/mSnO<sub>2</sub>). This synthesis method features the utilization of single-atom-modified mesoporous polydopamine nanospheres as the intermediate, whose phenolic hydroxyl and imine groups enable the formation of the SnO<sub>2</sub> skeleton and stabilization of SA, respectively. A library of stable gas-sensing inks is prepared based on the obtained SA/mSnO<sub>2</sub> nanospheres, enabling wafer-scale fabrication of sensing layers on microelectromechanical systems chips through high-speed printing. These as-fabricated SA/mSnO<sub>2</sub> sensors exhibit tailored selectivity due to different single-atom modifications, high sensitivity (5.6 times higher than that of commercial sensors), and excellent device-to-device consistency. Furthermore, by integrating different SA/mSnO<sub>2</sub> nanodevices into sensor arrays, an advanced intelligent olfactory system is produced and further integrated into an automated guided vehicle, enabling the autonomous identification and transport of low-concentration leaked chemicals.","PeriodicalId":49,"journal":{"name":"Journal of the American Chemical Society","volume":"13 1","pages":""},"PeriodicalIF":15.0,"publicationDate":"2025-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145711436","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}
Although many molecular catalysts for electrochemical reduction of carbon dioxide (CO2) to formic acid (HCO2H) have been surveyed to date, catalytic mechanisms proposed are often based on computational studies of hypothetical intermediates that lack direct experimental evidence and thus remain poorly understood. A solid understanding of the reaction mechanism is thus crucial to develop more efficient molecular catalysts. Multioperando analysis was conducted for the electrochemical reduction of CO2 using gas diffusion electrodes (GDEs), where a heterogenized molecular iridium (Ir) catalyst was coordinated with a tetradentate 6,6'-bis(phosphinomethyl)-2,2'-bipyridyl ligand. Application to a GDE system maintained plasmon-enhanced particles on the electrode, enabling time course operando measurements. Operando X-ray absorption fine structure spectroscopy and surface-enhanced Raman scattering measurements were used to track real-time changes in the electronic/intermediate structure of the catalyst, where three Ir intermediates were observed on the path to HCO2H production. The appearance times of each Ir intermediate were clearly distinguishable and showed a high correlation with the activation energy values calculated from DFT calculations. A highly accurate reaction mechanism of heterogenized catalysis was corroborated experimentally, which is typically more difficult to elucidate than homogeneous catalysis.
{"title":"Mechanism of CO2 Electrolysis with Heterogenized Molecular Iridium Catalysts Deciphered Using Operando Spectroscopy.","authors":"Naonari Sakamoto,Keita Sekizawa,Shunsuke Sato,Jieun Jung,Taku Wakabayashi,Kenji Kamada,Takamasa Nonaka,Takeshi Uyama,Takeshi Morikawa,Susumu Saito","doi":"10.1021/jacs.5c19250","DOIUrl":"https://doi.org/10.1021/jacs.5c19250","url":null,"abstract":"Although many molecular catalysts for electrochemical reduction of carbon dioxide (CO2) to formic acid (HCO2H) have been surveyed to date, catalytic mechanisms proposed are often based on computational studies of hypothetical intermediates that lack direct experimental evidence and thus remain poorly understood. A solid understanding of the reaction mechanism is thus crucial to develop more efficient molecular catalysts. Multioperando analysis was conducted for the electrochemical reduction of CO2 using gas diffusion electrodes (GDEs), where a heterogenized molecular iridium (Ir) catalyst was coordinated with a tetradentate 6,6'-bis(phosphinomethyl)-2,2'-bipyridyl ligand. Application to a GDE system maintained plasmon-enhanced particles on the electrode, enabling time course operando measurements. Operando X-ray absorption fine structure spectroscopy and surface-enhanced Raman scattering measurements were used to track real-time changes in the electronic/intermediate structure of the catalyst, where three Ir intermediates were observed on the path to HCO2H production. The appearance times of each Ir intermediate were clearly distinguishable and showed a high correlation with the activation energy values calculated from DFT calculations. A highly accurate reaction mechanism of heterogenized catalysis was corroborated experimentally, which is typically more difficult to elucidate than homogeneous catalysis.","PeriodicalId":49,"journal":{"name":"Journal of the American Chemical Society","volume":"140 1","pages":""},"PeriodicalIF":15.0,"publicationDate":"2025-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145704638","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}
Dipankar Sahoo,Devendra S Maurya,Jasper Adamson,Benjamin E Partridge,Mihai Peterca,Virgil Percec
Our laboratory has reported an unprecedented cogwheel mechanism of helical self-organization, which generates microdomains of single-handed supramolecular columns while disregarding the chirality of its building blocks. Discovered with a dendronized perylene bisimide (PBI), this mechanism arranges the alkyl groups of the self-assembling dendrons parallel to the helical column, providing the most compact helical construct known. Four precise molecular elements were originally considered to be required by the design of this helical structure. The first three elements─alkyl group length, the presence of a chiral methyl group on the alkyl chain, and the parallel arrangement of the helical coat to the column long axis─were demanded by a dimer of the dendronized PBI with 45° internal rotation of PBI units within dimer and a 90° rotation of dimers along the column long axis. Previous experiments demonstrated that a self-repairing process relaxes the number of carbons and eliminates the need for a chiral methyl group within the alkyl chains of the dendronized building block, essential to predict the helical half-pitch and helical coat arrangement. In this work, we demonstrate that the PBI dimer can be replaced by a repeat unit formed from one PBI and three nondendronized aromatic groups. Combined with the previously reported results, this extraordinary tolerance of the cogwheel mechanism to structural defects places it high on the list of models to study the origins of biological homochirality and for numerous practical applications.
{"title":"Extraordinary Tolerance of the Cogwheel Mechanism of Helical Self-Organization to Structural Defects.","authors":"Dipankar Sahoo,Devendra S Maurya,Jasper Adamson,Benjamin E Partridge,Mihai Peterca,Virgil Percec","doi":"10.1021/jacs.5c18057","DOIUrl":"https://doi.org/10.1021/jacs.5c18057","url":null,"abstract":"Our laboratory has reported an unprecedented cogwheel mechanism of helical self-organization, which generates microdomains of single-handed supramolecular columns while disregarding the chirality of its building blocks. Discovered with a dendronized perylene bisimide (PBI), this mechanism arranges the alkyl groups of the self-assembling dendrons parallel to the helical column, providing the most compact helical construct known. Four precise molecular elements were originally considered to be required by the design of this helical structure. The first three elements─alkyl group length, the presence of a chiral methyl group on the alkyl chain, and the parallel arrangement of the helical coat to the column long axis─were demanded by a dimer of the dendronized PBI with 45° internal rotation of PBI units within dimer and a 90° rotation of dimers along the column long axis. Previous experiments demonstrated that a self-repairing process relaxes the number of carbons and eliminates the need for a chiral methyl group within the alkyl chains of the dendronized building block, essential to predict the helical half-pitch and helical coat arrangement. In this work, we demonstrate that the PBI dimer can be replaced by a repeat unit formed from one PBI and three nondendronized aromatic groups. Combined with the previously reported results, this extraordinary tolerance of the cogwheel mechanism to structural defects places it high on the list of models to study the origins of biological homochirality and for numerous practical applications.","PeriodicalId":49,"journal":{"name":"Journal of the American Chemical Society","volume":"6 1","pages":""},"PeriodicalIF":15.0,"publicationDate":"2025-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145704640","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}
Sara Grecchi, Gerardo Salinas, Malinee Niamlaem, Alexander Kuhn, Serena Arnaboldi
Herein, we report the first miniaturized, wireless electrochemical flow reactor capable of performing both reactant pumping and asymmetric synthesis within a single, integrated device. The reactor consists of a hollow, conductive polymer tube where the outer polypyrrole (Ppy) shell acts as an electromechanical pump, and the inner layer, constituted of a chiral thiophene-based oligomer, serves as the enantioselective catalyst. This integrated design overcomes mass-transport limitations and eliminates the need for external pumps. By employing an alternating current (AC) protocol, we achieve near-quantitative yield (99%) and exceptional enantioselectivity (>99% ee) for the reduction of acetophenone. The system’s utility is showcased across three mechanistically distinct transformations, ketone reduction, sulfide oxidation, and reductive amination, culminating in the direct asymmetric synthesis of Ugi’s amine, the chiral probe used in our mechanistic studies, with high stereocontrol (>99.5% ee). This work introduces a new paradigm for reagent-free, pump-free asymmetric synthesis and provides a validated, predictive model for the rational design of smart, automated chemical manufacturing platforms.
{"title":"Unplugging Asymmetric Synthesis with a Wireless, Self-Pumping Electrochemical Reactor","authors":"Sara Grecchi, Gerardo Salinas, Malinee Niamlaem, Alexander Kuhn, Serena Arnaboldi","doi":"10.1021/jacs.5c16187","DOIUrl":"https://doi.org/10.1021/jacs.5c16187","url":null,"abstract":"Herein, we report the first miniaturized, wireless electrochemical flow reactor capable of performing both reactant pumping and asymmetric synthesis within a single, integrated device. The reactor consists of a hollow, conductive polymer tube where the outer polypyrrole (Ppy) shell acts as an electromechanical pump, and the inner layer, constituted of a chiral thiophene-based oligomer, serves as the enantioselective catalyst. This integrated design overcomes mass-transport limitations and eliminates the need for external pumps. By employing an alternating current (AC) protocol, we achieve near-quantitative yield (99%) and exceptional enantioselectivity (>99% ee) for the reduction of acetophenone. The system’s utility is showcased across three mechanistically distinct transformations, ketone reduction, sulfide oxidation, and reductive amination, culminating in the direct asymmetric synthesis of Ugi’s amine, the chiral probe used in our mechanistic studies, with high stereocontrol (>99.5% ee). This work introduces a new paradigm for reagent-free, pump-free asymmetric synthesis and provides a validated, predictive model for the rational design of smart, automated chemical manufacturing platforms.","PeriodicalId":49,"journal":{"name":"Journal of the American Chemical Society","volume":"39 1","pages":""},"PeriodicalIF":15.0,"publicationDate":"2025-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145711431","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}
Sanghyeok Im, Kelly E. Varnell, Alok K. Pandey, Peyman Asghari-Rad, Tae-Sic Yoo, Hojong Kim
This work investigated the impact of fluoride anions on Nd metal recovery in LiCl–KCl–NdCl3 electrolytes by introducing LiF at a molar F/Nd ratio of 9 at 773 K. The voltammetric measurements confirmed that the fluoride ions facilitated single-step Nd(III)/Nd reduction by promoting the stability of the Nd(III) state compared to two-step reduction (Nd(III)/Nd(II) and Nd(II)/Nd) in all-chloride electrolytes. The stabilized Nd(III) state in the LiF-containing electrolyte effectively suppressed partial Nd(III)/Nd(II) reduction and the back-dissolution of Nd metal via comproportionation. By suppressing these reactions, high round-trip Coulombic efficiencies of 77–86% were achieved in the LiF-containing electrolyte during selective Nd deposition–removal cycles compared to 53–59% in all-chloride electrolytes. The Faradaic yield for Nd metal recovery was estimated at 38.6% in the LiF-containing electrolyte following long-term electrolysis, more than three times higher than 11.3% in all-chloride electrolytes. These results confirm the beneficial effect of fluoride ions on Nd metal recovery in low-melting chloride-based electrolytes, promising efficient Nd recovery at low temperatures.
{"title":"Effect of Fluoride Anions on Nd(III) Electrode Processes and Nd Metal Recovery in LiCl–KCl–NdCl3","authors":"Sanghyeok Im, Kelly E. Varnell, Alok K. Pandey, Peyman Asghari-Rad, Tae-Sic Yoo, Hojong Kim","doi":"10.1021/jacs.5c15099","DOIUrl":"https://doi.org/10.1021/jacs.5c15099","url":null,"abstract":"This work investigated the impact of fluoride anions on Nd metal recovery in LiCl–KCl–NdCl<sub>3</sub> electrolytes by introducing LiF at a molar F/Nd ratio of 9 at 773 K. The voltammetric measurements confirmed that the fluoride ions facilitated single-step Nd(III)/Nd reduction by promoting the stability of the Nd(III) state compared to two-step reduction (Nd(III)/Nd(II) and Nd(II)/Nd) in all-chloride electrolytes. The stabilized Nd(III) state in the LiF-containing electrolyte effectively suppressed partial Nd(III)/Nd(II) reduction and the back-dissolution of Nd metal via comproportionation. By suppressing these reactions, high round-trip Coulombic efficiencies of 77–86% were achieved in the LiF-containing electrolyte during selective Nd deposition–removal cycles compared to 53–59% in all-chloride electrolytes. The Faradaic yield for Nd metal recovery was estimated at 38.6% in the LiF-containing electrolyte following long-term electrolysis, more than three times higher than 11.3% in all-chloride electrolytes. These results confirm the beneficial effect of fluoride ions on Nd metal recovery in low-melting chloride-based electrolytes, promising efficient Nd recovery at low temperatures.","PeriodicalId":49,"journal":{"name":"Journal of the American Chemical Society","volume":"5 1","pages":""},"PeriodicalIF":15.0,"publicationDate":"2025-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145704748","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}
Bhavish Dinakar,Juan F Torres,Mostapha Dakhchoune,Griffin Drake,Yogesh Surendranath,Mircea Dincă,Yuriy Román-Leshkov
Interfacial electric fields at heterogeneous catalyst surfaces have been demonstrated to alter kinetics of liquid-phase reactions. In these systems, electric fields are generated from applying a potential to the catalyst through connection to a potentiostat or through electron transfer from redox-active species in solution. Here, we demonstrate that catalyst polarization can also occur by simply contacting electrically conductive inert solids, leading to the counterintuitive conclusion that a catalyst particle touching an inert solid can alter intrinsic reaction rates. Using dehydration of 1-methylcyclopentanol to 1-methylcyclopentene catalyzed by Brønsted-acidic carboxylic acid groups on carbon nanotubes as a proof-of-concept probe reaction, we show that catalyst contact with inert, thermally reduced carbon nanotubes leads to order-of-magnitude changes in reaction rate. Furthermore, we demonstrate that these contact-induced effects can also be observed under standard laboratory reaction conditions, where particle-to-particle contact in stirred catalyst powder suspensions is sufficient to demote rates by ∼8-fold. This work provides the foundation for a new method of reaction rate control, which could have implications whenever heterogeneous catalyst particles are in contact with inert materials for liquid-phase reactions in the presence of electrolyte.
{"title":"Contact with Electrically Conductive Inert Solids Alters Intrinsic Heterogeneous Brønsted Acid Catalysis.","authors":"Bhavish Dinakar,Juan F Torres,Mostapha Dakhchoune,Griffin Drake,Yogesh Surendranath,Mircea Dincă,Yuriy Román-Leshkov","doi":"10.1021/jacs.5c12973","DOIUrl":"https://doi.org/10.1021/jacs.5c12973","url":null,"abstract":"Interfacial electric fields at heterogeneous catalyst surfaces have been demonstrated to alter kinetics of liquid-phase reactions. In these systems, electric fields are generated from applying a potential to the catalyst through connection to a potentiostat or through electron transfer from redox-active species in solution. Here, we demonstrate that catalyst polarization can also occur by simply contacting electrically conductive inert solids, leading to the counterintuitive conclusion that a catalyst particle touching an inert solid can alter intrinsic reaction rates. Using dehydration of 1-methylcyclopentanol to 1-methylcyclopentene catalyzed by Brønsted-acidic carboxylic acid groups on carbon nanotubes as a proof-of-concept probe reaction, we show that catalyst contact with inert, thermally reduced carbon nanotubes leads to order-of-magnitude changes in reaction rate. Furthermore, we demonstrate that these contact-induced effects can also be observed under standard laboratory reaction conditions, where particle-to-particle contact in stirred catalyst powder suspensions is sufficient to demote rates by ∼8-fold. This work provides the foundation for a new method of reaction rate control, which could have implications whenever heterogeneous catalyst particles are in contact with inert materials for liquid-phase reactions in the presence of electrolyte.","PeriodicalId":49,"journal":{"name":"Journal of the American Chemical Society","volume":"1 1","pages":""},"PeriodicalIF":15.0,"publicationDate":"2025-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145704677","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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