Pub Date : 2025-02-05DOI: 10.1021/acs.jpclett.4c03734
J. Fransson, R. Naaman
Redox processes that involve pairs of electrons are common in nature. Some of these reactions involve oxygen molecules. The understanding of the efficiency of the oxygen reduction reaction (ORR), for example, is a challenge since the reaction is spin forbidden and requires the transfer of two pairs of electrons. Past experimental and theoretical studies demonstrated that by controlling the spin of the transferred electrons, it is possible to overcome the barrier resulting from the spin mismatch between the reactants and the products. In other works, it was suggested that the reaction is enhanced if the two electrons in each pair have phase relation, namely, they possess the property of a triplet state. Since in nature electrons are transferred through chiral systems, we probed if chirality affects the formation of paired electrons with the same spin, namely, a triplet like state. The model calculations demonstrate that chirality enhances the probability of the formation of electron pairing in the triplet states, even at room temperature. This enhancement originates from breaking the spin degeneracy, enabled by chirality and interaction of the spins with vibrations.
{"title":"Chirality Assisted Triplet Electron Pairing","authors":"J. Fransson, R. Naaman","doi":"10.1021/acs.jpclett.4c03734","DOIUrl":"https://doi.org/10.1021/acs.jpclett.4c03734","url":null,"abstract":"Redox processes that involve pairs of electrons are common in nature. Some of these reactions involve oxygen molecules. The understanding of the efficiency of the oxygen reduction reaction (ORR), for example, is a challenge since the reaction is spin forbidden and requires the transfer of two pairs of electrons. Past experimental and theoretical studies demonstrated that by controlling the spin of the transferred electrons, it is possible to overcome the barrier resulting from the spin mismatch between the reactants and the products. In other works, it was suggested that the reaction is enhanced if the two electrons in each pair have phase relation, namely, they possess the property of a triplet state. Since in nature electrons are transferred through chiral systems, we probed if chirality affects the formation of paired electrons with the same spin, namely, a triplet like state. The model calculations demonstrate that chirality enhances the probability of the formation of electron pairing in the triplet states, even at room temperature. This enhancement originates from breaking the spin degeneracy, enabled by chirality and interaction of the spins with vibrations.","PeriodicalId":62,"journal":{"name":"The Journal of Physical Chemistry Letters","volume":"207 1","pages":""},"PeriodicalIF":6.475,"publicationDate":"2025-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143124685","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-04DOI: 10.1021/acs.jpclett.4c03267
Joy Chatterjee, Riteeka Tanwar, Anupama S, Abhijit Chatterjee, Madan D. Ambhore, Mukul Kabir, Pankaj Mandal, Partha Hazra
Organic–inorganic hybrid metal halides have become enormously important in optoelectronics, sensing, photosensitization, etc. In this study, we report a structural transition from a staircase configuration to a cubane configuration in Cu(I) iodide-based polymers influenced by the coordination behavior of two different π*-acceptor ligands. The staircase polymer structure, coordinated with 3-cyanopyridine, demonstrates efficient thermally activated delayed fluorescence from (metal+halide)-to-ligand charge transfer [1/3(M+X)LCT] states, with a singlet–triplet energy splitting of ∼9 meV. Conversely, upon replacement of the cyano with an amino group at the same position, a one-dimensional polymeric structure of Cu4I4 cubane-type clusters is formed, which shows strong cluster-centered (3CC) orange emission at room temperature. Temperature-dependent photoluminescence studies indicate that the 3CC state behaves as a self-trapped excitonic state with significant exciton–phonon coupling having a Huang–Rhys factor of 58.6. Additionally, we report this cubane-type cluster polymer acts as an efficient nonlinear optical material showing third harmonic generation with a χ(3) value of 1.32 × 10–18 m2 V–2 and a laser-induced damage threshold of 25.87 GW/cm2.
{"title":"Controlling Triplet-Harvesting Pathways and Nonlinear Optical Properties in Cu(I) Iodide-Based Polymers through Ligand Engineering","authors":"Joy Chatterjee, Riteeka Tanwar, Anupama S, Abhijit Chatterjee, Madan D. Ambhore, Mukul Kabir, Pankaj Mandal, Partha Hazra","doi":"10.1021/acs.jpclett.4c03267","DOIUrl":"https://doi.org/10.1021/acs.jpclett.4c03267","url":null,"abstract":"Organic–inorganic hybrid metal halides have become enormously important in optoelectronics, sensing, photosensitization, etc. In this study, we report a structural transition from a staircase configuration to a cubane configuration in Cu(I) iodide-based polymers influenced by the coordination behavior of two different π*-acceptor ligands. The staircase polymer structure, coordinated with 3-cyanopyridine, demonstrates efficient thermally activated delayed fluorescence from (metal+halide)-to-ligand charge transfer [<sup>1/3</sup>(M+X)LCT] states, with a singlet–triplet energy splitting of ∼9 meV. Conversely, upon replacement of the cyano with an amino group at the same position, a one-dimensional polymeric structure of Cu<sub>4</sub>I<sub>4</sub> cubane-type clusters is formed, which shows strong cluster-centered (<sup>3</sup>CC) orange emission at room temperature. Temperature-dependent photoluminescence studies indicate that the <sup>3</sup>CC state behaves as a self-trapped excitonic state with significant exciton–phonon coupling having a Huang–Rhys factor of 58.6. Additionally, we report this cubane-type cluster polymer acts as an efficient nonlinear optical material showing third harmonic generation with a χ<sup>(3)</sup> value of 1.32 × 10<sup>–18</sup> m<sup>2</sup> V<sup>–2</sup> and a laser-induced damage threshold of 25.87 GW/cm<sup>2</sup>.","PeriodicalId":62,"journal":{"name":"The Journal of Physical Chemistry Letters","volume":"83 1","pages":""},"PeriodicalIF":6.475,"publicationDate":"2025-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143124686","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-04DOI: 10.1021/acs.jpclett.4c03476
C. Alexander Schrage, Phillip Galonska, Justus T. Metternich, Sebastian Kruss
Single-walled carbon nanotubes (SWCNTs) are versatile near-infrared (NIR) fluorophores that can be chemically functionalized to create biosensors. Numerous noncovalent approaches were developed to detect analytes, but these design concepts can be susceptible to nonspecific binding and reduced stability. In contrast, covalent modification of SWCNTs with quantum defects can be utilized to tune their fluorescence properties and enable new molecular recognition concepts. Here, we present and assess four different synthetic pathways/sequences to modify SWCNTs covalently with both sp3 quantum defects and DNA-based guanine defects. We find that it is possible to create two defect types without disrupting the optical properties or chemical stability. Interestingly, the emission peak associated with sp3 defects (E11*) shifts around 3 nm when combined with guanine defects, indicating a coupling between the two defect types. However, it is far lower than the red-shift in bandgap-related emission (E11) by guanine quantum defects (40 nm). We furthermore demonstrate that combinations of defects can be used for (bio)sensing. In summary, the combination of multiple quantum defect types in SWCNTs provides a platform for multifunctional biosensors and a new design space that can be explored.
{"title":"Photophysical Properties of Tandem Quantum Defects in Carbon Nanotubes","authors":"C. Alexander Schrage, Phillip Galonska, Justus T. Metternich, Sebastian Kruss","doi":"10.1021/acs.jpclett.4c03476","DOIUrl":"https://doi.org/10.1021/acs.jpclett.4c03476","url":null,"abstract":"Single-walled carbon nanotubes (SWCNTs) are versatile near-infrared (NIR) fluorophores that can be chemically functionalized to create biosensors. Numerous noncovalent approaches were developed to detect analytes, but these design concepts can be susceptible to nonspecific binding and reduced stability. In contrast, covalent modification of SWCNTs with quantum defects can be utilized to tune their fluorescence properties and enable new molecular recognition concepts. Here, we present and assess four different synthetic pathways/sequences to modify SWCNTs covalently with both sp<sup>3</sup> quantum defects and DNA-based guanine defects. We find that it is possible to create two defect types without disrupting the optical properties or chemical stability. Interestingly, the emission peak associated with sp<sup>3</sup> defects (E<sub>11</sub>*) shifts around 3 nm when combined with guanine defects, indicating a coupling between the two defect types. However, it is far lower than the red-shift in bandgap-related emission (E<sub>11</sub>) by guanine quantum defects (40 nm). We furthermore demonstrate that combinations of defects can be used for (bio)sensing. In summary, the combination of multiple quantum defect types in SWCNTs provides a platform for multifunctional biosensors and a new design space that can be explored.","PeriodicalId":62,"journal":{"name":"The Journal of Physical Chemistry Letters","volume":"55 1","pages":""},"PeriodicalIF":6.475,"publicationDate":"2025-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143124688","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Quasi-two-dimensional CdSe nanoplatelets (NPLs) exhibit promising potential for optoelectronic device applications due to their unique optical properties, particularly trion emission. However, the origin of the trion emission in CdSe NPLs remains unclear. In this study, the steady-state optical properties of CdSe NPLs with different CdSeS crown widths have been investigated. At low temperature, the trion emission intensity decreases with the increase of the CdSeS crown width. Using n-butylamine to remove cadmium oleate from NPLs, it is confirmed that holes in CdSe NPLs are captured by cadmium vacancies, leading to a charge imbalance and trion emission. At room temperature, thermal energy (26 meV) facilitates the escape of holes, eliminating the trion emission and shortening the fluorescence lifetime with the increase in CdSeS crown width. This work clarifies the origin of trion emission in CdSe NPLs and offers insights into the design of optoelectronic devices based on trion emission.
{"title":"Investigation of Trion Emission in CdSe/CdSeS Core/Crown Nanoplatelets","authors":"Huan Liu, Puning Wang, Zhihao Huang, Shan Wang, Zhiyuan Ren, Jinwei Liu, Tingchao He, Rui Chen","doi":"10.1021/acs.jpclett.4c03637","DOIUrl":"https://doi.org/10.1021/acs.jpclett.4c03637","url":null,"abstract":"Quasi-two-dimensional CdSe nanoplatelets (NPLs) exhibit promising potential for optoelectronic device applications due to their unique optical properties, particularly trion emission. However, the origin of the trion emission in CdSe NPLs remains unclear. In this study, the steady-state optical properties of CdSe NPLs with different CdSeS crown widths have been investigated. At low temperature, the trion emission intensity decreases with the increase of the CdSeS crown width. Using <i>n</i>-butylamine to remove cadmium oleate from NPLs, it is confirmed that holes in CdSe NPLs are captured by cadmium vacancies, leading to a charge imbalance and trion emission. At room temperature, thermal energy (26 meV) facilitates the escape of holes, eliminating the trion emission and shortening the fluorescence lifetime with the increase in CdSeS crown width. This work clarifies the origin of trion emission in CdSe NPLs and offers insights into the design of optoelectronic devices based on trion emission.","PeriodicalId":62,"journal":{"name":"The Journal of Physical Chemistry Letters","volume":"76 1","pages":""},"PeriodicalIF":6.475,"publicationDate":"2025-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143124689","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-04DOI: 10.1021/acs.jpclett.4c02939
Logan M. Hennes, Chloe Behringer, Mohsen Farshad, Jennifer L. Schaefer, Jonathan K. Whitmer
Solid-state electrolytes are currently being explored as a safe material capable of addressing consumer energy-storage demands. Solid polymer electrolytes, in particular, offer a high energy density and improved safety when compared to liquid-based electrolytes, but tend to have a significantly lower ionic conductivity. We hypothesize structured ionic liquids can enhance conductivity compared to polymer electrolytes. Here, we explore the performance of these materials through coarse-grained molecular dynamics simulation. While we observe similar phase behavior (incorporating solid, smectic, and liquid phases) to that seen in experiments, we also observe significantly more mobility in the cationic species compared to the anionic species before the system reaches an arrest transition. We further discuss how the general results within this paper can guide further studies and target the design of new highly conductive solid electrolytes with the potential to enable the use of multivalent ionic species as ion conductors.
{"title":"Controlling Electrostatics To Enhance Conductivity in Structured Electrolytes","authors":"Logan M. Hennes, Chloe Behringer, Mohsen Farshad, Jennifer L. Schaefer, Jonathan K. Whitmer","doi":"10.1021/acs.jpclett.4c02939","DOIUrl":"https://doi.org/10.1021/acs.jpclett.4c02939","url":null,"abstract":"Solid-state electrolytes are currently being explored as a safe material capable of addressing consumer energy-storage demands. Solid polymer electrolytes, in particular, offer a high energy density and improved safety when compared to liquid-based electrolytes, but tend to have a significantly lower ionic conductivity. We hypothesize structured ionic liquids can enhance conductivity compared to polymer electrolytes. Here, we explore the performance of these materials through coarse-grained molecular dynamics simulation. While we observe similar phase behavior (incorporating solid, smectic, and liquid phases) to that seen in experiments, we also observe significantly more mobility in the cationic species compared to the anionic species before the system reaches an arrest transition. We further discuss how the general results within this paper can guide further studies and target the design of new highly conductive solid electrolytes with the potential to enable the use of multivalent ionic species as ion conductors.","PeriodicalId":62,"journal":{"name":"The Journal of Physical Chemistry Letters","volume":"28 1","pages":""},"PeriodicalIF":6.475,"publicationDate":"2025-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143124684","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-04DOI: 10.1021/acs.jpclett.4c03120
Lyndon A. Hall, Hunter J. Windsor, Bun Chan, Deanna M. D’Alessandro, Girish Lakhwani
Molecules whose chiroptical signal can be controllably and reversibly altered are of great interest in emerging optoelectronic technologies. Here, we outline the synthesis of a pair of chiral enantiomers (S)-1,1′-binaphthalene-2,2′-bis(1,8-naphthalimide) and (R)-1,1′-binaphthalene-2,2′-bis(1,8-naphthalimide) and their characterization with a range of structural, electrochemical, and spectroelectrochemical techniques. We show that reduction of the naphthalimide moieties in each enantiomer causes substantial changes in their optical and chiroptical properties, enabling them to perform as highly sensitive and reversible redox-modulated chiroptical switches.
{"title":"Chiroptical Switching in an Enantiomeric Pair of Binaphthylenes Based on Redox-Active 1,8-Naphthalimide Substituents","authors":"Lyndon A. Hall, Hunter J. Windsor, Bun Chan, Deanna M. D’Alessandro, Girish Lakhwani","doi":"10.1021/acs.jpclett.4c03120","DOIUrl":"https://doi.org/10.1021/acs.jpclett.4c03120","url":null,"abstract":"Molecules whose chiroptical signal can be controllably and reversibly altered are of great interest in emerging optoelectronic technologies. Here, we outline the synthesis of a pair of chiral enantiomers (<i>S</i>)-1,1′-binaphthalene-2,2′-bis(1,8-naphthalimide) and (<i>R</i>)-1,1′-binaphthalene-2,2′-bis(1,8-naphthalimide) and their characterization with a range of structural, electrochemical, and spectroelectrochemical techniques. We show that reduction of the naphthalimide moieties in each enantiomer causes substantial changes in their optical and chiroptical properties, enabling them to perform as highly sensitive and reversible redox-modulated chiroptical switches.","PeriodicalId":62,"journal":{"name":"The Journal of Physical Chemistry Letters","volume":"67 1 1","pages":""},"PeriodicalIF":6.475,"publicationDate":"2025-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143083654","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Surface modification of semiconductors with noble metals has been shown to effectively tune their photocatalytic activity. However, the photoinduced charge transfer processes at the metal/semiconductor interface and their impact on the concentration of surface-reaching photoexcited charges remain subjects of ongoing debate. In this study, we used time-resolved spectroscopy and kinetic analysis to investigate the behavior of surface-reaching photoholes in metal-loaded TiO2 nanoparticles. Our results reveal that the concentration of surface-reaching photoholes (Ch+(surf)) is highly dependent upon the type of metal and the resulting metal–oxide interface. Among the noble metals studied (Pt, Au, and Ag), Pt loading led to the most significant increase in Ch+(surf), with a nearly 3-fold enhancement compared to pristine TiO2. This enhancement was attributed to the generation of more abundant Ti3+ defects at the metal–oxide interface, which serve as hole trap states, thereby accelerating interfacial charge transfer, improving charge separation, and enriching Ch+(surf). These findings underscore the critical role of the metal–oxide interface in enhancing surface-reaching photoexcited charges, offering valuable insights for the design of advanced materials for solar energy conversion.
{"title":"Spectroscopic Kinetic Insights into the Critical Role of Metal–Oxide Interfaces in Enhancing the Concentration of Surface-Reaching Photoexcited Charges","authors":"Jiaqiang Sun, Yachao Wang, Yu Wang, Yaxiong Wei, Xinsheng Xu, Shuo Chen, Weixin Huang, Guofeng Zhao, Cong Fu","doi":"10.1021/acs.jpclett.4c03606","DOIUrl":"https://doi.org/10.1021/acs.jpclett.4c03606","url":null,"abstract":"Surface modification of semiconductors with noble metals has been shown to effectively tune their photocatalytic activity. However, the photoinduced charge transfer processes at the metal/semiconductor interface and their impact on the concentration of surface-reaching photoexcited charges remain subjects of ongoing debate. In this study, we used time-resolved spectroscopy and kinetic analysis to investigate the behavior of surface-reaching photoholes in metal-loaded TiO<sub>2</sub> nanoparticles. Our results reveal that the concentration of surface-reaching photoholes (<i>C</i><sub>h+(surf)</sub>) is highly dependent upon the type of metal and the resulting metal–oxide interface. Among the noble metals studied (Pt, Au, and Ag), Pt loading led to the most significant increase in <i>C</i><sub>h+(surf)</sub>, with a nearly 3-fold enhancement compared to pristine TiO<sub>2</sub>. This enhancement was attributed to the generation of more abundant Ti<sup>3+</sup> defects at the metal–oxide interface, which serve as hole trap states, thereby accelerating interfacial charge transfer, improving charge separation, and enriching <i>C</i><sub>h+(surf)</sub>. These findings underscore the critical role of the metal–oxide interface in enhancing surface-reaching photoexcited charges, offering valuable insights for the design of advanced materials for solar energy conversion.","PeriodicalId":62,"journal":{"name":"The Journal of Physical Chemistry Letters","volume":"7 1","pages":""},"PeriodicalIF":6.475,"publicationDate":"2025-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143083652","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-04DOI: 10.1021/acs.jpclett.5c00005
Xinlei Zhang, Jing Leng, Qi Sun, Hui Cheng, Fengke Sun, Yejun Xiao, Yan Xu, Wenming Tian, Shengye Jin
Mn-doped perovskite nanocrystals (NCs) exhibit great application potential because of their unique optical properties. However, the long-lived nature of excited Mn2+ easily leads to the coexistence of excited Mn2+ and host excitons in a single NC, which inevitably induces an Auger cross relaxation between them, thus significantly limiting the luminescent efficiency of Mn2+ due to its competition with internal energy transfer. Herein, we design and prepare a kind of Mn-doped core–shell CsPbCl3@Cs4PbCl6 perovskite NC with Mn2+ doped only in the shell layer, which is expected to suppress this Auger process by spatially separating the electronic wave functions. By using pump–pump–probe transient absorption spectroscopy, we demonstrate that the core–shell structure effectively suppresses the Auger process with the Auger relaxation time notably extended from 12.1 to 148.3 ps. Our finding offers an effective strategy to suppress this Auger process in Mn-doped NCs, which is greatly significant for improving their luminescent efficiency.
{"title":"Suppression of Auger Cross Relaxation in Mn-Doped Core–Shell Perovskite Nanocrystals via Wave Function Engineering","authors":"Xinlei Zhang, Jing Leng, Qi Sun, Hui Cheng, Fengke Sun, Yejun Xiao, Yan Xu, Wenming Tian, Shengye Jin","doi":"10.1021/acs.jpclett.5c00005","DOIUrl":"https://doi.org/10.1021/acs.jpclett.5c00005","url":null,"abstract":"Mn-doped perovskite nanocrystals (NCs) exhibit great application potential because of their unique optical properties. However, the long-lived nature of excited Mn<sup>2+</sup> easily leads to the coexistence of excited Mn<sup>2+</sup> and host excitons in a single NC, which inevitably induces an Auger cross relaxation between them, thus significantly limiting the luminescent efficiency of Mn<sup>2+</sup> due to its competition with internal energy transfer. Herein, we design and prepare a kind of Mn-doped core–shell CsPbCl<sub>3</sub>@Cs<sub>4</sub>PbCl<sub>6</sub> perovskite NC with Mn<sup>2+</sup> doped only in the shell layer, which is expected to suppress this Auger process by spatially separating the electronic wave functions. By using pump–pump–probe transient absorption spectroscopy, we demonstrate that the core–shell structure effectively suppresses the Auger process with the Auger relaxation time notably extended from 12.1 to 148.3 ps. Our finding offers an effective strategy to suppress this Auger process in Mn-doped NCs, which is greatly significant for improving their luminescent efficiency.","PeriodicalId":62,"journal":{"name":"The Journal of Physical Chemistry Letters","volume":"133 1","pages":""},"PeriodicalIF":6.475,"publicationDate":"2025-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143084180","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-04DOI: 10.1021/acs.jpclett.4c03272
Asuka J. Iwasaki, Marcin Kirsz, Ciprian G. Pruteanu, Graeme J. Ackland
We have developed two machine-learned pair potentials for krypton based on CCSD(T) quantum chemical calculations on two and three atom clusters. Through extensive testing with molecular dynamics, we find both potentials give good agreement with the experimental equation of state, melting point, and neutron scattering data for the fluid. Compared with the most widely used Lennard-Jones model, our potentials produced similar results in low-pressure melting and equation of state. However, extending the regime to higher pressures of ≤30 GPa showed a remarkable divergence of the Lennard-Jones model from the experimental (solid) equation of state. Our potential showed extremely good agreement, despite having no solid phases in the training set.
{"title":"An Accurate Machine-Learned Potential for Krypton under Extreme Conditions","authors":"Asuka J. Iwasaki, Marcin Kirsz, Ciprian G. Pruteanu, Graeme J. Ackland","doi":"10.1021/acs.jpclett.4c03272","DOIUrl":"https://doi.org/10.1021/acs.jpclett.4c03272","url":null,"abstract":"We have developed two machine-learned pair potentials for krypton based on CCSD(T) quantum chemical calculations on two and three atom clusters. Through extensive testing with molecular dynamics, we find both potentials give good agreement with the experimental equation of state, melting point, and neutron scattering data for the fluid. Compared with the most widely used Lennard-Jones model, our potentials produced similar results in low-pressure melting and equation of state. However, extending the regime to higher pressures of ≤30 GPa showed a remarkable divergence of the Lennard-Jones model from the experimental (solid) equation of state. Our potential showed extremely good agreement, despite having no solid phases in the training set.","PeriodicalId":62,"journal":{"name":"The Journal of Physical Chemistry Letters","volume":"15 1","pages":""},"PeriodicalIF":6.475,"publicationDate":"2025-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143124687","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Bifunctional enzymes that execute tandem chemical reactions progress through orchestrated conformational states to achieve chemical synchronization. In these allosterically regulated systems, specific stimuli, such as substrate and cofactor binding, determine reactivity. Here, we employ a combination of steady-state and time-resolved fluorescence methods to monitor the conformational dynamics of a catalytic loop in formylglycinamidine synthetase, an enzyme that catalyzes a crucial step toward the synthesis of precursors of DNA and RNA. We show that the catalytic loop harbors adaptive structural elements that change secondary structure in response to substrate binding and, thereby, enable allosteric cues to the 25 Å distal NH3-producing site. To exclusively track the conformational changes in the loop, a fluorescent unnatural amino acid was introduced into the 1300-amino acid protein, allowing for a unique signal that was not masked by the indigenous fluorescent amino acids. The study highlights the role of flexible small elements that act as triggers of the allosteric cycle and maps states that are essential for function.
{"title":"Substrate-Induced Dynamic Regulation of the Catalytic Loop in Assisting Allosteric Communication in Formylglycinamidine Synthetase","authors":"Sukhwinder Singh, Tanuja Kistwal, Anindya Datta, Ruchi Anand","doi":"10.1021/acs.jpclett.4c03172","DOIUrl":"https://doi.org/10.1021/acs.jpclett.4c03172","url":null,"abstract":"Bifunctional enzymes that execute tandem chemical reactions progress through orchestrated conformational states to achieve chemical synchronization. In these allosterically regulated systems, specific stimuli, such as substrate and cofactor binding, determine reactivity. Here, we employ a combination of steady-state and time-resolved fluorescence methods to monitor the conformational dynamics of a catalytic loop in formylglycinamidine synthetase, an enzyme that catalyzes a crucial step toward the synthesis of precursors of DNA and RNA. We show that the catalytic loop harbors adaptive structural elements that change secondary structure in response to substrate binding and, thereby, enable allosteric cues to the 25 Å distal NH<sub>3</sub>-producing site. To exclusively track the conformational changes in the loop, a fluorescent unnatural amino acid was introduced into the 1300-amino acid protein, allowing for a unique signal that was not masked by the indigenous fluorescent amino acids. The study highlights the role of flexible small elements that act as triggers of the allosteric cycle and maps states that are essential for function.","PeriodicalId":62,"journal":{"name":"The Journal of Physical Chemistry Letters","volume":"29 1","pages":""},"PeriodicalIF":6.475,"publicationDate":"2025-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143124732","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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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