Electron transport through a single quantum channel is fundamentally limited by the conductance quantum (G0 = 2e2/h ≈ 77.5 μS), achievable only in fully transparent systems without interfacial scattering. However, realizing this quantum limit in metal-molecule-metal junctions has long been hindered by intrinsic electronic mismatches at heterogeneous interfaces. Here, we report a carbon nanobelt single-molecule junction over 1 nm in length, whose conductance reaches G0, driven by the saturation of a single transport channel under ambient conditions. This unprecedented performance arises from electric-field-induced formation of covalent C-Au-C bonds at both contacts, creating atomically fused interfaces that seamlessly merge the nanobelt's π system with Au d orbitals. The resulting d-π conjugation establishes a single, transparent electronic resonance aligned with the Fermi level, suppressing backscattering and enabling near ideal quantum transport. By eliminating heterogeneous interfacial resistance at the atomic scale, this strategy offers a general blueprint for engineering atomically precise, energy-efficient nanoelectronic and optoelectronic devices.
{"title":"Single-Channel Saturation at the Quantum Conductance Limit in Single-Molecule Junctions.","authors":"Junfeng Lin, Bingchen Liu, Bing-Zhong Hu, Yongfeng Wang, Jing-Tao Lü, Yaping Zang, Daoben Zhu","doi":"10.1021/jacs.5c18067","DOIUrl":"https://doi.org/10.1021/jacs.5c18067","url":null,"abstract":"<p><p>Electron transport through a single quantum channel is fundamentally limited by the conductance quantum (<i>G</i><sub>0</sub> = 2e<sup>2</sup>/<i>h</i> ≈ 77.5 μS), achievable only in fully transparent systems without interfacial scattering. However, realizing this quantum limit in metal-molecule-metal junctions has long been hindered by intrinsic electronic mismatches at heterogeneous interfaces. Here, we report a carbon nanobelt single-molecule junction over 1 nm in length, whose conductance reaches <i>G</i><sub>0</sub>, driven by the saturation of a single transport channel under ambient conditions. This unprecedented performance arises from electric-field-induced formation of covalent C-Au-C bonds at both contacts, creating atomically fused interfaces that seamlessly merge the nanobelt's π system with Au d orbitals. The resulting d-π conjugation establishes a single, transparent electronic resonance aligned with the Fermi level, suppressing backscattering and enabling near ideal quantum transport. By eliminating heterogeneous interfacial resistance at the atomic scale, this strategy offers a general blueprint for engineering atomically precise, energy-efficient nanoelectronic and optoelectronic devices.</p>","PeriodicalId":49,"journal":{"name":"Journal of the American Chemical Society","volume":" ","pages":""},"PeriodicalIF":15.6,"publicationDate":"2026-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146130451","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}
Zhan-Hong Ye, Qiao-Qiao Ao, Yang-Chao Peng, Xin Liu, Xing Lin, Chuang-Chuang Li
The first total synthesis of (±)- and (+)-euphohyrisnoid A, a highly rearranged lathyrane Euphorbia diterpenoid with a new [5–7–6–6] tetracyclic core, was accomplished. The synthesis was strategically guided by a mild intramolecular Diels–Alder (IMDA) reaction, which efficiently constructed the pivotal bicyclo[2.2.2] ring system with high diastereoselectivity. This outcome experimentally validated prior quantum mechanical calculations. The IMDA precursor was assembled efficiently via a Tsuji–Trost reaction. The desired seven stereocenters, including two quaternary stereocenters in the final product, were constructed diastereoselectively.
{"title":"Total Synthesis of (±)- and (+)-Euphohyrisnoid A","authors":"Zhan-Hong Ye, Qiao-Qiao Ao, Yang-Chao Peng, Xin Liu, Xing Lin, Chuang-Chuang Li","doi":"10.1021/jacs.6c00187","DOIUrl":"https://doi.org/10.1021/jacs.6c00187","url":null,"abstract":"The first total synthesis of (±)- and (+)-euphohyrisnoid A, a highly rearranged lathyrane <i>Euphorbia</i> diterpenoid with a new [5–7–6–6] tetracyclic core, was accomplished. The synthesis was strategically guided by a mild intramolecular Diels–Alder (IMDA) reaction, which efficiently constructed the pivotal bicyclo[2.2.2] ring system with high diastereoselectivity. This outcome experimentally validated prior quantum mechanical calculations. The IMDA precursor was assembled efficiently via a Tsuji–Trost reaction. The desired seven stereocenters, including two quaternary stereocenters in the final product, were constructed diastereoselectively.","PeriodicalId":49,"journal":{"name":"Journal of the American Chemical Society","volume":"47 1","pages":""},"PeriodicalIF":15.0,"publicationDate":"2026-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146122264","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}
Leon Schlosser, Nils H. Rendel, Julius Gemen, Frank Glorius, Kjell Jorner
The discovery of new organic photocatalysts (PCs) for energy transfer (EnT) catalysis remains a significant challenge, largely due to the vast and underexplored chemical space and the delicate balance of the photocatalytic properties. While transition-metal catalysts are effective, their high cost and environmental impact necessitate the development of metal-free alternatives. In this work, we present a hybrid inverse molecular design strategy that combines global exploration with targeted local optimization to discover highly efficient organic PCs. Our approach leverages a generative model, guided by machine learning predictions and semiempirical simulations, to efficiently navigate chemical space and identify promising molecular scaffolds. We demonstrate the utility of this strategy by rediscovering known PCs and, more importantly, exploring uncharted structural regions, leading to the identification of novel candidates with favorable photophysical properties. A subsequent local exploration stage, using quantum mechanical calculations, allows refinement of the properties as well as control of the synthetic complexity. The practical applicability of the approach is demonstrated by performing a local exploration of one of the identified scaffolds and successfully synthesizing four candidate PCs. We showcase their catalytic aptitude in three different EnT-mediated reactions, including a challenging aza-photocycloaddition, where one of our designed PCs achieved 90% yield, a performance comparable to a state-of-the-art iridium-based catalyst. This study highlights the power of a data-driven inverse design framework to bridge computational discovery and experimental validation, accelerating the identification of novel PCs and expanding the scope of EnT catalysis.
{"title":"Inverse Molecular Design for the Discovery of Organic Energy Transfer Photocatalysts: Bridging Global and Local Chemical Space Exploration","authors":"Leon Schlosser, Nils H. Rendel, Julius Gemen, Frank Glorius, Kjell Jorner","doi":"10.1021/jacs.5c20087","DOIUrl":"https://doi.org/10.1021/jacs.5c20087","url":null,"abstract":"The discovery of new organic photocatalysts (PCs) for energy transfer (EnT) catalysis remains a significant challenge, largely due to the vast and underexplored chemical space and the delicate balance of the photocatalytic properties. While transition-metal catalysts are effective, their high cost and environmental impact necessitate the development of metal-free alternatives. In this work, we present a hybrid inverse molecular design strategy that combines global exploration with targeted local optimization to discover highly efficient organic PCs. Our approach leverages a generative model, guided by machine learning predictions and semiempirical simulations, to efficiently navigate chemical space and identify promising molecular scaffolds. We demonstrate the utility of this strategy by rediscovering known PCs and, more importantly, exploring uncharted structural regions, leading to the identification of novel candidates with favorable photophysical properties. A subsequent local exploration stage, using quantum mechanical calculations, allows refinement of the properties as well as control of the synthetic complexity. The practical applicability of the approach is demonstrated by performing a local exploration of one of the identified scaffolds and successfully synthesizing four candidate PCs. We showcase their catalytic aptitude in three different EnT-mediated reactions, including a challenging aza-photocycloaddition, where one of our designed PCs achieved 90% yield, a performance comparable to a state-of-the-art iridium-based catalyst. This study highlights the power of a data-driven inverse design framework to bridge computational discovery and experimental validation, accelerating the identification of novel PCs and expanding the scope of EnT catalysis.","PeriodicalId":49,"journal":{"name":"Journal of the American Chemical Society","volume":"16 1","pages":""},"PeriodicalIF":15.0,"publicationDate":"2026-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146122523","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}
Yan Li, Jing-Wen Shi, Guo-Ping Yang, Ya-Qian Lan, Jiang Liu, Yao-Yu Wang
Photosensitizers (PSs) play crucial roles in photocatalysis by efficiently harvesting light and facilitating photoinduced charge transfer. However, whether they are applied in a homogeneous solution or immobilized on catalysts, PSs are prone to deactivation through leaching or desorption, leading to a significant decline in photocatalytic performance. Herein, two highly photoactive metal–organic frameworks (MOFs) denoted as NWUM-Cd-s and NWUM-Cd were constructed from Cd(II) ions, 4,4′,4′′-nitrilotribenzoic acid (H3TCA), and a classic [Ru(bpy)3]2+ PS via cocrystallization. These MOFs can firmly lock the [Ru(bpy)3]2+ PS through the structural characteristics of DNA-like double-helix and “···ABABA···” dislocation stacking. This prevents the PS from deactivating during the photocatalytic process, which enables these MOFs to exhibit excellent photocatalytic activity and long-term cycling stability in the model CO2 photoreduction reaction. The CO production rate of interpenetrated NWUM-Cd-s (13.9 mmol g–1 h–1) is 5.3 times that of dislocated monolayer NWUM-Cd (2.6 mmol g–1 h–1). In situ characterizations and theoretical calculations reveal that the interpenetrated structure of NWUM-Cd-s significantly enhances the separation of photogenerated charges, which in turn reduces the overall reaction energy barrier and promotes electron–proton transfer cooperativity, thus leading to more outstanding photoactivity than that of NWUM-Cd. This work demonstrates unprecedented staggered stacking and DNA-like interlocking strategies to lock PSs in catalysts, thereby tackling the long-standing challenges in traditional photocatalysis of low light utilization efficiency, PS deactivation, and slow charge transfer.
{"title":"Locking Photosensitizers into Staggered-Stacking and DNA-Interlocked Metal–Organic Frameworks for Outstanding CO2 Photoreduction Activity","authors":"Yan Li, Jing-Wen Shi, Guo-Ping Yang, Ya-Qian Lan, Jiang Liu, Yao-Yu Wang","doi":"10.1021/jacs.5c19716","DOIUrl":"https://doi.org/10.1021/jacs.5c19716","url":null,"abstract":"Photosensitizers (PSs) play crucial roles in photocatalysis by efficiently harvesting light and facilitating photoinduced charge transfer. However, whether they are applied in a homogeneous solution or immobilized on catalysts, PSs are prone to deactivation through leaching or desorption, leading to a significant decline in photocatalytic performance. Herein, two highly photoactive metal–organic frameworks (MOFs) denoted as <b>NWUM-Cd-</b><i>s</i> and <b>NWUM-Cd</b> were constructed from Cd(II) ions, 4,4′,4′′-nitrilotribenzoic acid (H<sub>3</sub>TCA), and a classic [Ru(bpy)<sub>3</sub>]<sup>2+</sup> PS via cocrystallization. These MOFs can firmly lock the [Ru(bpy)<sub>3</sub>]<sup>2+</sup> PS through the structural characteristics of DNA-like double-helix and “···ABABA···” dislocation stacking. This prevents the PS from deactivating during the photocatalytic process, which enables these MOFs to exhibit excellent photocatalytic activity and long-term cycling stability in the model CO<sub>2</sub> photoreduction reaction. The CO production rate of interpenetrated <b>NWUM-Cd-</b><i>s</i> (13.9 mmol g<sup>–1</sup> h<sup>–1</sup>) is 5.3 times that of dislocated monolayer <b>NWUM-Cd</b> (2.6 mmol g<sup>–1</sup> h<sup>–1</sup>). In situ characterizations and theoretical calculations reveal that the interpenetrated structure of <b>NWUM-Cd-</b><i>s</i> significantly enhances the separation of photogenerated charges, which in turn reduces the overall reaction energy barrier and promotes electron–proton transfer cooperativity, thus leading to more outstanding photoactivity than that of <b>NWUM-Cd</b>. This work demonstrates unprecedented staggered stacking and DNA-like interlocking strategies to lock PSs in catalysts, thereby tackling the long-standing challenges in traditional photocatalysis of low light utilization efficiency, PS deactivation, and slow charge transfer.","PeriodicalId":49,"journal":{"name":"Journal of the American Chemical Society","volume":"57 1","pages":""},"PeriodicalIF":15.0,"publicationDate":"2026-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146122257","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}
Wenhao Sun, Steffen M. Giesen, Robert Berger, Melanie Schnell
Weakly bound complexes containing lead (Pb) were studied in a supersonic jet using broadband chirped-pulse Fourier transform microwave (CP-FTMW) spectroscopy, complemented with quantum-chemical calculations. These complexes were formed from a vapor mixture of tetraethyllead (TEL) and 2-(trifluoromethyl)oxirane (TFO), diluted in a Ne carrier gas. Theoretical isomer searches reveal 75 nearly isoenergetic isomers of the TEL-TFO dimer, all within an energy range of 1.0 kJ/mol. Rotational spectroscopy has unambiguously identified the global-minimum configuration in the ground vibrational state, including its three singly substituted 206/207/208Pb isotopologues. This assignment is further supported by the observation of the TEL-TFO-Ne trimer, which gives rise to six doubly substituted 206/207/208Pb-20/22Ne isotopologues in their natural abundance. The experimental data provides a valuable benchmark for assessing modern quantum-chemical methods, particularly in the treatment of relativistic effects of heavy nuclei along with noncovalent interactions. Additionally, as heavy-atom-containing chiral complexes, parity-violating effects were calculated for the TEL-TFO dimer at various levels of theory, shedding light on parity nonconservation in weakly bound complexes involving heavy nuclei.
{"title":"Chirality Induced in Tetraethyllead through Noncovalent Interactions with a Chiral Tag","authors":"Wenhao Sun, Steffen M. Giesen, Robert Berger, Melanie Schnell","doi":"10.1021/jacs.5c21116","DOIUrl":"https://doi.org/10.1021/jacs.5c21116","url":null,"abstract":"Weakly bound complexes containing lead (Pb) were studied in a supersonic jet using broadband chirped-pulse Fourier transform microwave (CP-FTMW) spectroscopy, complemented with quantum-chemical calculations. These complexes were formed from a vapor mixture of tetraethyllead (TEL) and 2-(trifluoromethyl)oxirane (TFO), diluted in a Ne carrier gas. Theoretical isomer searches reveal 75 nearly isoenergetic isomers of the TEL-TFO dimer, all within an energy range of 1.0 kJ/mol. Rotational spectroscopy has unambiguously identified the global-minimum configuration in the ground vibrational state, including its three singly substituted <sup>206/207/208</sup>Pb isotopologues. This assignment is further supported by the observation of the TEL-TFO-Ne trimer, which gives rise to six doubly substituted <sup>206/207/208</sup>Pb-<sup>20/22</sup>Ne isotopologues in their natural abundance. The experimental data provides a valuable benchmark for assessing modern quantum-chemical methods, particularly in the treatment of relativistic effects of heavy nuclei along with noncovalent interactions. Additionally, as heavy-atom-containing chiral complexes, parity-violating effects were calculated for the TEL-TFO dimer at various levels of theory, shedding light on parity nonconservation in weakly bound complexes involving heavy nuclei.","PeriodicalId":49,"journal":{"name":"Journal of the American Chemical Society","volume":"12 1","pages":""},"PeriodicalIF":15.0,"publicationDate":"2026-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146122260","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}
Long-term in vivo neurochemical sensing with aptamer-based electrochemical sensors is fundamentally limited by the enzymatic degradation of natural D-DNA aptamers and the instability of surface-confined sensing interfaces. Here, we generate a mirror-image L-DNA analogue of a dopamine-binding aptamer and show that chiral inversion preserves folding, affinity, and selectivity, as confirmed by circular dichroism, fluorescence binding assays, and molecular docking. Integration of this L-aptamer with a stabilized electrochemical conjugation on carbon–fiber microelectrodes yields a highly stable mirror-image molecular–electrical interface capable of sensitively transducing dopamine binding into quantitative electrochemical signals. Owing to its exceptional nuclease resistance, the L-aptamer sensor enables continuous dopamine monitoring in vivo for over 24 h─an order-of-magnitude improvement in signal over conventional D-aptamer sensors. Applied in Parkinson’s disease mouse model, the sensor resolves pathological dopamine clearance defects. These results establish mirror-image nucleic acids, when coupled with engineered electrochemical interfaces, as effective components for durable bioelectronic sensing in vivo.
{"title":"Mirror-Image L-DNA Aptamers Enable Stable In Vivo Dopamine Sensing","authors":"Yinghuan Liu, Ying Jin, Fenghui Zhu, Xin Li, Chunran Ma, Zhining Sun, Yichun Yao, Kaixin Song, Lanqun Mao, Ying Jiang","doi":"10.1021/jacs.5c22265","DOIUrl":"https://doi.org/10.1021/jacs.5c22265","url":null,"abstract":"Long-term in vivo neurochemical sensing with aptamer-based electrochemical sensors is fundamentally limited by the enzymatic degradation of natural D-DNA aptamers and the instability of surface-confined sensing interfaces. Here, we generate a mirror-image L-DNA analogue of a dopamine-binding aptamer and show that chiral inversion preserves folding, affinity, and selectivity, as confirmed by circular dichroism, fluorescence binding assays, and molecular docking. Integration of this L-aptamer with a stabilized electrochemical conjugation on carbon–fiber microelectrodes yields a highly stable mirror-image molecular–electrical interface capable of sensitively transducing dopamine binding into quantitative electrochemical signals. Owing to its exceptional nuclease resistance, the L-aptamer sensor enables continuous dopamine monitoring in vivo for over 24 h─an order-of-magnitude improvement in signal over conventional D-aptamer sensors. Applied in Parkinson’s disease mouse model, the sensor resolves pathological dopamine clearance defects. These results establish mirror-image nucleic acids, when coupled with engineered electrochemical interfaces, as effective components for durable bioelectronic sensing in vivo.","PeriodicalId":49,"journal":{"name":"Journal of the American Chemical Society","volume":"23 1","pages":""},"PeriodicalIF":15.0,"publicationDate":"2026-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146122263","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}
Achieving efficient synergy between covalent and supramolecular polymers is an effective strategy for developing novel polymeric materials. However, realizing this synergy through rational chemical design to efficiently integrate both types of polymers within a single polymer network remains a significant challenge. Here, we achieve efficient synergy between covalent and supramolecular polymer chains by inducing entanglement of unsymmetrical topological nodes. Benefiting from the molecular entanglement strategy, this synergistic network effectively integrates the stability of a covalent polymer and the dynamics of a supramolecular polymer. While maintaining the integrity of the network, the reversible host–guest recognition in the supramolecular polymer dissipates the applied energy, thus allowing the mechanical properties of the entire network to be regulated. Besides, the host–guest recognition pairs can serve as splicing points for integrating additional polymers, transforming the topologically entangled covalent-supramolecular synergistic polymer platform into a multifunctional platform that accommodates a variety of polymers, significantly increasing the diversity of their structures and properties. These findings may spur further innovations in the field of polymers in general, as well as promote a deeper understanding of dynamic chemistry.
{"title":"Synergistic Covalent and Supramolecular Polymer Networks Enabled by Unsymmetrical Topological Nodes","authors":"Xue Yang, Zhewen Guo, Liya Chen, Yuling Pan, Zejian He, Zhenguo Zhang, Honggang Mei, Nan Jiang, Xiaole Tao, Ding Xiao, Guangfeng Li, Feihe Huang","doi":"10.1021/jacs.5c20730","DOIUrl":"https://doi.org/10.1021/jacs.5c20730","url":null,"abstract":"Achieving efficient synergy between covalent and supramolecular polymers is an effective strategy for developing novel polymeric materials. However, realizing this synergy through rational chemical design to efficiently integrate both types of polymers within a single polymer network remains a significant challenge. Here, we achieve efficient synergy between covalent and supramolecular polymer chains by inducing entanglement of unsymmetrical topological nodes. Benefiting from the molecular entanglement strategy, this synergistic network effectively integrates the stability of a covalent polymer and the dynamics of a supramolecular polymer. While maintaining the integrity of the network, the reversible host–guest recognition in the supramolecular polymer dissipates the applied energy, thus allowing the mechanical properties of the entire network to be regulated. Besides, the host–guest recognition pairs can serve as splicing points for integrating additional polymers, transforming the topologically entangled covalent-supramolecular synergistic polymer platform into a multifunctional platform that accommodates a variety of polymers, significantly increasing the diversity of their structures and properties. These findings may spur further innovations in the field of polymers in general, as well as promote a deeper understanding of dynamic chemistry.","PeriodicalId":49,"journal":{"name":"Journal of the American Chemical Society","volume":"58 1","pages":""},"PeriodicalIF":15.0,"publicationDate":"2026-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146122258","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}
Chang Liu, Di Zhang, Jiaxiang Chen, Fangxin She, Fangzhou Liu, Zixun Yu, Zhi Zheng, Matthew S. Levine, Jonathan L. Sessler, Yuan Chen, Hao Li, Li Wei
The coordination number between the bound metal center and the supporting nitrogen atoms in single-metal-atom nitrogen–carbon catalysts (M–N–C) is an important structural parameter that can impact the catalytic activity. Understanding the structure–activity relationship between coordination number and catalytic activity is made challenging by difficulties in obtaining M–N–C catalysts with precisely controlled metal–nitrogen coordination environments. Herein, we address this challenge using heterogeneous molecular catalysts for the oxygen reduction reaction (ORR) constructed by depositing structure-defined organometallic molecules on a catalytically inert carbon nanotube substrate. The explicit metal–nitrogen coordination environments enabled us to establish accurate ORR activity–structure correlations for cobalt metal centers with first-shell Co–N coordination numbers of 3 to 5 (Co–Nx, where x = 3, 4, and 5). A good agreement between theoretical predictions and experimental ORR activity and selectivity was seen. Of note, Co atoms in an asymmetric coordination environment were found to exhibit higher activity for the two-electron (2e) ORR. Kinetic studies and operando spectroscopic measurements further revealed that the first-shell coordinating C or N atoms in asymmetric Co–N3 and Co–N5 centers could be protonated and participate in the ORR as a proton relay. The present study may aid in understanding the role of the coordination environment in other metal-based catalytic systems being applied to renewable energy conversion reactions.
{"title":"Coordination-Dependent Oxygen Reduction Reaction Activity of Single Atom Co–Nx–C Electrocatalysts","authors":"Chang Liu, Di Zhang, Jiaxiang Chen, Fangxin She, Fangzhou Liu, Zixun Yu, Zhi Zheng, Matthew S. Levine, Jonathan L. Sessler, Yuan Chen, Hao Li, Li Wei","doi":"10.1021/jacs.5c20980","DOIUrl":"https://doi.org/10.1021/jacs.5c20980","url":null,"abstract":"The coordination number between the bound metal center and the supporting nitrogen atoms in single-metal-atom nitrogen–carbon catalysts (M–N–C) is an important structural parameter that can impact the catalytic activity. Understanding the structure–activity relationship between coordination number and catalytic activity is made challenging by difficulties in obtaining M–N–C catalysts with precisely controlled metal–nitrogen coordination environments. Herein, we address this challenge using heterogeneous molecular catalysts for the oxygen reduction reaction (ORR) constructed by depositing structure-defined organometallic molecules on a catalytically inert carbon nanotube substrate. The explicit metal–nitrogen coordination environments enabled us to establish accurate ORR activity–structure correlations for cobalt metal centers with first-shell Co–N coordination numbers of 3 to 5 (Co–N<i>x</i>, where <i>x</i> = 3, 4, and 5). A good agreement between theoretical predictions and experimental ORR activity and selectivity was seen. Of note, Co atoms in an asymmetric coordination environment were found to exhibit higher activity for the two-electron (2e) ORR. Kinetic studies and <i>operando</i> spectroscopic measurements further revealed that the first-shell coordinating C or N atoms in asymmetric Co–N3 and Co–N5 centers could be protonated and participate in the ORR as a proton relay. The present study may aid in understanding the role of the coordination environment in other metal-based catalytic systems being applied to renewable energy conversion reactions.","PeriodicalId":49,"journal":{"name":"Journal of the American Chemical Society","volume":"83 1","pages":""},"PeriodicalIF":15.0,"publicationDate":"2026-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146122259","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}
Yuxuan Xiong, Jinhong Li, Chaoyu Wang, Langston Tillman, Xiaomin Jiang, Alitza L Soiffer, Ralph R Weichselbaum, Wenbin Lin
Tumor resistance to radiotherapy (RT) and immune checkpoint blockade (ICB) is frequently driven by an immunosuppressive tumor microenvironment, where hypoxia and elevated redox buffering impair both cytotoxic and immune responses. Here, we report a new type of metal-organic framework (MOF)-based radiosensitizer, Pt/Hf-Ir-DBB, that integrates high Z-element-mediated RT enhancement, catalytic redox disruption, and sustained chemotherapeutic delivery into a single multifunctional platform. By confining ultrafine platinum nanoclusters (Pt NCs) within the photoactive Hf-Ir-DBB MOF via photoreduction, this multifunctional system amplifies the hydroxyl radical and singlet oxygen generation under X-ray irradiation. The embedded mixed-valence Pt NCs exhibit potent catalytic activities toward NADH oxidation, H2O2 decomposition, and GSH depletion, thereby alleviating hypoxia and disrupting mitochondrial redox homeostasis. Acting as a sustained-release depot, Pt/Hf-Ir-DBB gradually releases Pt2+ ions for prolonged chemotherapeutic action. This multimodal strategy reprograms the tumor microenvironment by promoting M1-like macrophage polarization and remodeling the extracellular matrix, ultimately facilitating CD8+ T cell activation and infiltration and restoring responsiveness to ICB. In murine colorectal cancer and triple-negative breast cancer models, Pt/Hf-Ir-DBB combined with low-dose X-ray irradiation synergistically enhances both local tumor control and systemic antitumor immunity. These findings establish a rational strategy for overcoming metabolic and immune resistance using MOF-based multifunctional nanoradiosensitizers.
{"title":"Spatial Confinement of Platinum Nanoclusters in a Photoactive Metal-Organic Framework for Radiotherapy Enhancement and Redox-Mediated Immune Activation.","authors":"Yuxuan Xiong, Jinhong Li, Chaoyu Wang, Langston Tillman, Xiaomin Jiang, Alitza L Soiffer, Ralph R Weichselbaum, Wenbin Lin","doi":"10.1021/jacs.5c21748","DOIUrl":"https://doi.org/10.1021/jacs.5c21748","url":null,"abstract":"<p><p>Tumor resistance to radiotherapy (RT) and immune checkpoint blockade (ICB) is frequently driven by an immunosuppressive tumor microenvironment, where hypoxia and elevated redox buffering impair both cytotoxic and immune responses. Here, we report a new type of metal-organic framework (MOF)-based radiosensitizer, Pt/Hf-Ir-DBB, that integrates high Z-element-mediated RT enhancement, catalytic redox disruption, and sustained chemotherapeutic delivery into a single multifunctional platform. By confining ultrafine platinum nanoclusters (Pt NCs) within the photoactive Hf-Ir-DBB MOF via photoreduction, this multifunctional system amplifies the hydroxyl radical and singlet oxygen generation under X-ray irradiation. The embedded mixed-valence Pt NCs exhibit potent catalytic activities toward NADH oxidation, H<sub>2</sub>O<sub>2</sub> decomposition, and GSH depletion, thereby alleviating hypoxia and disrupting mitochondrial redox homeostasis. Acting as a sustained-release depot, Pt/Hf-Ir-DBB gradually releases Pt<sup>2+</sup> ions for prolonged chemotherapeutic action. This multimodal strategy reprograms the tumor microenvironment by promoting M1-like macrophage polarization and remodeling the extracellular matrix, ultimately facilitating CD8<sup>+</sup> T cell activation and infiltration and restoring responsiveness to ICB. In murine colorectal cancer and triple-negative breast cancer models, Pt/Hf-Ir-DBB combined with low-dose X-ray irradiation synergistically enhances both local tumor control and systemic antitumor immunity. These findings establish a rational strategy for overcoming metabolic and immune resistance using MOF-based multifunctional nanoradiosensitizers.</p>","PeriodicalId":49,"journal":{"name":"Journal of the American Chemical Society","volume":" ","pages":""},"PeriodicalIF":15.6,"publicationDate":"2026-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146130424","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}
Hyunchul Kwon, K. Randall McClain, Jakob K. Staab, Patrick W. Smith, Benjamin G. Harvey, Matthew P. Erodici, Simon J. Teat, T. David Harris, Stefan Minasian, Nicholas F. Chilton, Jeffrey R. Long
Mixed-valence complexes featuring lanthanide–lanthanide bonding have recently been shown to act as single-molecule magnets with unprecedented operating temperatures and magnetic coercivities. Here, we present the synthesis and detailed examination of the electronic structure, bonding, and magnetic properties of mixed-valence trinuclear clusters (C5iPr5)3Ln3H3I2 (Ln = Tb, Dy, Ho, Er, and Tm). Near-infrared and X-ray absorption spectra, together with computational results, confirm these clusters possess a three-center, one-electron σ bond. This metal–metal bonding leads to strong intermetal exchange coupling, resulting in magnetic behaviors that starkly contrast with typical multinuclear lanthanide complexes. Notably, structural, spectroscopic, and computational studies of the thulium cluster reveal valence delocalization through a bonding orbital of 5d-parentage between the three Tm centers. This observation represents the first example of a nontraditional electronic structure for thulium involving 5d rather than 4f orbitals. Magnetic analysis reveals a complex interplay between single-ion magnetic anisotropy and ferromagnetic exchange, governing the overall magnetic anisotropy of these clusters. Magnetic susceptibility measurements for Ln = Tb–Er indicate thermally well-isolated high-moment ground states arising from strong magnetic coupling, although the maximum values are lower than those expected for complete parallel alignment of the σ and 4f electrons. Computational analyses suggest that collinear alignment of the local anisotropy axes results in out-of-plane anisotropy for Ln = Er and Tm, whereas noncollinear alignment induces in-plane anisotropy for Ln = Tb, Dy, leading to distinct magnetic relaxation properties. Together, the results highlight the diverse magnetic behaviors that can be realized through lanthanide–lanthanide bonding and outline a synthetic path forward toward maximizing the magnetic anisotropy in f-element clusters.
{"title":"Triangular (C5iPr5)3Ln3H3I2 (Ln = Tb, Dy, Ho, Er, Tm) Clusters with Lanthanide-Dependent Bonding, Valence Delocalization, and Magnetic Anisotropy","authors":"Hyunchul Kwon, K. Randall McClain, Jakob K. Staab, Patrick W. Smith, Benjamin G. Harvey, Matthew P. Erodici, Simon J. Teat, T. David Harris, Stefan Minasian, Nicholas F. Chilton, Jeffrey R. Long","doi":"10.1021/jacs.5c19340","DOIUrl":"https://doi.org/10.1021/jacs.5c19340","url":null,"abstract":"Mixed-valence complexes featuring lanthanide–lanthanide bonding have recently been shown to act as single-molecule magnets with unprecedented operating temperatures and magnetic coercivities. Here, we present the synthesis and detailed examination of the electronic structure, bonding, and magnetic properties of mixed-valence trinuclear clusters (C<sub>5</sub><sup><i>i</i></sup>Pr<sub>5</sub>)<sub>3</sub>Ln<sub>3</sub>H<sub>3</sub>I<sub>2</sub> (Ln = Tb, Dy, Ho, Er, and Tm). Near-infrared and X-ray absorption spectra, together with computational results, confirm these clusters possess a three-center, one-electron σ bond. This metal–metal bonding leads to strong intermetal exchange coupling, resulting in magnetic behaviors that starkly contrast with typical multinuclear lanthanide complexes. Notably, structural, spectroscopic, and computational studies of the thulium cluster reveal valence delocalization through a bonding orbital of 5d-parentage between the three Tm centers. This observation represents the first example of a nontraditional electronic structure for thulium involving 5d rather than 4f orbitals. Magnetic analysis reveals a complex interplay between single-ion magnetic anisotropy and ferromagnetic exchange, governing the overall magnetic anisotropy of these clusters. Magnetic susceptibility measurements for Ln = Tb–Er indicate thermally well-isolated high-moment ground states arising from strong magnetic coupling, although the maximum values are lower than those expected for complete parallel alignment of the σ and 4f electrons. Computational analyses suggest that collinear alignment of the local anisotropy axes results in out-of-plane anisotropy for Ln = Er and Tm, whereas noncollinear alignment induces in-plane anisotropy for Ln = Tb, Dy, leading to distinct magnetic relaxation properties. Together, the results highlight the diverse magnetic behaviors that can be realized through lanthanide–lanthanide bonding and outline a synthetic path forward toward maximizing the magnetic anisotropy in f-element clusters.","PeriodicalId":49,"journal":{"name":"Journal of the American Chemical Society","volume":"28 1","pages":""},"PeriodicalIF":15.0,"publicationDate":"2026-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146122522","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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