Electrometric titration techniques have long been used to detect the Li+ diffusion coefficient of electrode materials. However, the influence of electrode additives, cell assembly methods, especially, inaccurate assessments of the reaction area often led to unreliable results. Here, we propose a molecular titration technique (MTT) to detect lithium diffusion coefficient (DLi) in LiFePO4. This MTT alleviates the tedious electrode preparation procedure, circumvents the influence of additives, amends the real reaction area errors, and shortens the testing time, making the testing more precise and efficient than the traditional titration techniques. In detail, [Fe(CN)6]3- solution is added into LiFePO4 solid dropwise, while potential change rate (rp) of the solution is recorded. Thereafter, a built-in electric field (BIEF) electron transferring model is established and the relationship between DLi and rp is formulated with Huggins-Weppner equation. Eventually, the de-lithiation diffusion coefficient of Li1-xFePO4 (1≤x≤0) is tested to be 1~8×10-15 cm2/s based on the recorded data and established formulations.
{"title":"A molecular titration strategy: utilizing built-in electric field to detect lithium diffusion coefficient in LiFePO4","authors":"Juezhi Yu, Zexin Lin, Zhihao Deng, Xianrun Cao, Lu Guo, FeiFei Zhang, Sheng Liu, Gangfeng Ouyang","doi":"10.1039/d5cp00481k","DOIUrl":"https://doi.org/10.1039/d5cp00481k","url":null,"abstract":"Electrometric titration techniques have long been used to detect the Li+ diffusion coefficient of electrode materials. However, the influence of electrode additives, cell assembly methods, especially, inaccurate assessments of the reaction area often led to unreliable results. Here, we propose a molecular titration technique (MTT) to detect lithium diffusion coefficient (DLi) in LiFePO4. This MTT alleviates the tedious electrode preparation procedure, circumvents the influence of additives, amends the real reaction area errors, and shortens the testing time, making the testing more precise and efficient than the traditional titration techniques. In detail, [Fe(CN)6]3- solution is added into LiFePO4 solid dropwise, while potential change rate (rp) of the solution is recorded. Thereafter, a built-in electric field (BIEF) electron transferring model is established and the relationship between DLi and rp is formulated with Huggins-Weppner equation. Eventually, the de-lithiation diffusion coefficient of Li1-xFePO4 (1≤x≤0) is tested to be 1~8×10-15 cm2/s based on the recorded data and established formulations.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"7 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143862156","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Electro-chemical conversion of carbon dioxide stands out as an excellent strategy to alleviate the greenhouse effect. Lately, single atom catalysts have gained notable attention as emerging candidates for CO2 reduction reaction, owing to their remarkable cost-efficiency and unprecedented atomic utilization. Applying density functional theory (DFT), our work examines the first couple of proton coupled electron transfer steps of CO2RR, on 3d transition metal-doped B-Gr and compares the activity observed with previously studied supports. Since CO2 activation is the 1st step of CO2RR, we thoroughly investigated the capability of the TM SAs in effectively activating CO2 in both dry phase and in presence of water. According to our calculation, except Ti, Cu and Zn, all other TM@B-Gr systems are able to activate the CO2 molecule. CO2 activation on selected SACs is further attributed to the transfer of charges from the TM SA to the CO2 molecule, as revealed by our Bader charge calculations. In addition, the Gibbs free energy changes for all the reaction intermediates have been calculated to determine the most preferred pathway of the reaction. Our results indicate the preference for OCHO over COOH in the first protonation step, indicating the production of HCOOH as the preferred end product. The same trend has also been observed in presence of H2O. Our DFT based analysis presented in this work, unravels the crucial role a support plays in determining the activity of a single atom catalyst and paves a way forward to the efficient design of 2D catalyst for CO2 reduction reaction.
{"title":"Transition Metal Embedded Boron Doped Graphene for Reduction of CO2 to HCOOH","authors":"Sudatta Giri, Purushothaman Manivannan, Debolina Misra","doi":"10.1039/d5cp01427a","DOIUrl":"https://doi.org/10.1039/d5cp01427a","url":null,"abstract":"Electro-chemical conversion of carbon dioxide stands out as an excellent strategy to alleviate the greenhouse effect. Lately, single atom catalysts have gained notable attention as emerging candidates for CO<small><sub>2</sub></small> reduction reaction, owing to their remarkable cost-efficiency and unprecedented atomic utilization. Applying density functional theory (DFT), our work examines the first couple of proton coupled electron transfer steps of CO<small><sub>2</sub></small>RR, on 3d transition metal-doped B-Gr and compares the activity observed with previously studied supports. Since CO<small><sub>2</sub></small> activation is the 1st step of CO<small><sub>2</sub></small>RR, we thoroughly investigated the capability of the TM SAs in effectively activating CO<small><sub>2</sub></small> in both dry phase and in presence of water. According to our calculation, except Ti, Cu and Zn, all other TM@B-Gr systems are able to activate the CO<small><sub>2</sub></small> molecule. CO<small><sub>2</sub></small> activation on selected SACs is further attributed to the transfer of charges from the TM SA to the CO<small><sub>2</sub></small> molecule, as revealed by our Bader charge calculations. In addition, the Gibbs free energy changes for all the reaction intermediates have been calculated to determine the most preferred pathway of the reaction. Our results indicate the preference for OCHO over COOH in the first protonation step, indicating the production of HCOOH as the preferred end product. The same trend has also been observed in presence of H<small><sub>2</sub></small>O. Our DFT based analysis presented in this work, unravels the crucial role a support plays in determining the activity of a single atom catalyst and paves a way forward to the efficient design of 2D catalyst for CO<small><sub>2</sub></small> reduction reaction.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"63 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143862157","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We synthesized a novel NIR-emissive (785 nm) D-A•-type triphenylmethyl radical TTM-EMICz using a rigidly structured and large-conjugated donor 6-butylindolo[3,2-b]carbazole (ICz) unit. Studies showed that the non-Aufbau electronic structure and PL spectra of the radical can be regulated by the protonation process, in which the PL spectra of the radical can be adjusted to the visible region. Furthermore, the protonated radical TTM-EMICz shows emission centered at 610 nm and 633 nm with PLQY of 4.5 % and 14.9 % in cyclohexane and toluene, with excited state CT properties. The photostability investigation indicated that radical TTM-EMICz has 350 times higher photostability in cyclohexane compared to the well-known carbazole-capped radical TTM-1Cz. This is the first reported near-infrared organic radical with two-state-emissive characteristics (non-Aufbau and Aufbau electronic states), which can be adjusted by protonation/deprotonation process.
{"title":"A near-infrared luminescent organic radical with switchable emission and SOMO-HOMO inversion via protonation/deprotonation process","authors":"Obolda Ablikim, Parida Hazretomar, Mehrigul Abdulahat, Fudong Ma, Ayixiemuguli Tuersun, Zhaoze Ding, Zhuoyang Hu","doi":"10.1039/d5cp00399g","DOIUrl":"https://doi.org/10.1039/d5cp00399g","url":null,"abstract":"We synthesized a novel NIR-emissive (785 nm) D-A•-type triphenylmethyl radical TTM-EMICz using a rigidly structured and large-conjugated donor 6-butylindolo[3,2-b]carbazole (ICz) unit. Studies showed that the non-Aufbau electronic structure and PL spectra of the radical can be regulated by the protonation process, in which the PL spectra of the radical can be adjusted to the visible region. Furthermore, the protonated radical TTM-EMICz shows emission centered at 610 nm and 633 nm with PLQY of 4.5 % and 14.9 % in cyclohexane and toluene, with excited state CT properties. The photostability investigation indicated that radical TTM-EMICz has 350 times higher photostability in cyclohexane compared to the well-known carbazole-capped radical TTM-1Cz. This is the first reported near-infrared organic radical with two-state-emissive characteristics (non-Aufbau and Aufbau electronic states), which can be adjusted by protonation/deprotonation process.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"17 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143862159","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Chromosomal rearrangements involving the Mixed-Lineage Leukemia (MLL) gene are implicated in acute leukemias with poor prognosis. In MLL-rearranged leukemias, the aberrant recruitment of transcriptional and epigenetic modifier complexes is driven primarily by the MLL-AF9 fusion protein. AF9 typically inhibits transcription by recruiting BCL-6 corepressor (BCOR); however, the direct fusion of AF9 with MLL results in a loss of context dependence in AF9 recruitment and causes oncogenic transformation of hematopoietic cells. Notably, the E531R mutation in AF9, which disrupts the binding between the MLL-AF9 fusion protein and BCOR, abrogates the leukemogenic potential in a mouse model, underscoring its significance as a therapeutic target in leukemia. AF9 and BCOR interact through their intrinsically disordered regions (IDRs), which undergo conformational folding upon complex formation. Understanding this conformational transition is critical for guiding drug discovery efforts but interactions mediated by IDRs remain challenging to study due to their dynamic nature. We propose a hybrid method by combining conventional and Replica Exchange Molecular Dynamics (REMD) simulations, to investigate the binding free energy landscape (BFEL) of wild type (WT) and mutant (MT) AF9-BCOR complexes. REMD simulations of WT AF9 alone revealed a significant loss of β-sheets and mutation accelerated the rate of β-sheet disappearance due to the formation of non-native contacts. FEL of WT AF9-BCOR complex exhibited several local minima, highlighting C-terminal BCOR interactions as potential target for therapeutic intervention. Mutation disrupted the native interactions in AF9-BCOR complex and showed poor binding affinity. Our study uncovers the interaction dynamics of AF9-BCOR and introduces an innovative approach for mapping protein-protein interaction energy landscapes, offering valuable insights to advance targeted drug design.
{"title":"Exploring the Binding Free Energy Landscape of Intrinsically Disordered Protein-Protein Interactions: Insights into the AF9-BCOR Complex implicated in Leukemia","authors":"Shilpa Sharma, Arjun Saha","doi":"10.1039/d5cp01009h","DOIUrl":"https://doi.org/10.1039/d5cp01009h","url":null,"abstract":"Chromosomal rearrangements involving the Mixed-Lineage Leukemia (MLL) gene are implicated in acute leukemias with poor prognosis. In MLL-rearranged leukemias, the aberrant recruitment of transcriptional and epigenetic modifier complexes is driven primarily by the MLL-AF9 fusion protein. AF9 typically inhibits transcription by recruiting BCL-6 corepressor (BCOR); however, the direct fusion of AF9 with MLL results in a loss of context dependence in AF9 recruitment and causes oncogenic transformation of hematopoietic cells. Notably, the E531R mutation in AF9, which disrupts the binding between the MLL-AF9 fusion protein and BCOR, abrogates the leukemogenic potential in a mouse model, underscoring its significance as a therapeutic target in leukemia. AF9 and BCOR interact through their intrinsically disordered regions (IDRs), which undergo conformational folding upon complex formation. Understanding this conformational transition is critical for guiding drug discovery efforts but interactions mediated by IDRs remain challenging to study due to their dynamic nature. We propose a hybrid method by combining conventional and Replica Exchange Molecular Dynamics (REMD) simulations, to investigate the binding free energy landscape (BFEL) of wild type (WT) and mutant (MT) AF9-BCOR complexes. REMD simulations of WT AF9 alone revealed a significant loss of β-sheets and mutation accelerated the rate of β-sheet disappearance due to the formation of non-native contacts. FEL of WT AF9-BCOR complex exhibited several local minima, highlighting C-terminal BCOR interactions as potential target for therapeutic intervention. Mutation disrupted the native interactions in AF9-BCOR complex and showed poor binding affinity. Our study uncovers the interaction dynamics of AF9-BCOR and introduces an innovative approach for mapping protein-protein interaction energy landscapes, offering valuable insights to advance targeted drug design.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"219 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143862153","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Christopher Gort, Gustavo T. Feliciano, Alexander A. Auer, Bernhard Kaiser, W. Jaegermann, Jan Philipp Hofmann
Nickel-based oxides are among the best performing catalysts for the alkaline O2 evolution reaction (OER). It has long been recognized that iron enhances the catalytic activity of nickel-based catalysts, though only recently intensive research has been done on the interplay between the two transition metals, leading to the excellent performance, surpassing that of either pure metal. It is still not clear how the electronic configuration in mixed metal compounds changes to enhance their catalytic activity for the OER. We carried out a systematic study of the electronic configuration of thin film mixed metal oxides Ni(1-x)FexOyHz with varying contents x of iron. In this investigation we employed X-ray absorption and resonant valence photoelectron spectroscopy (XAS and resPES) to gain knowledge on the changes induced in the electronic structure by introduction of iron, both before and after electrochemical activation. Based on density functional calculations we found iron species to induce a highly oxidizing environment that facilitates generation of oxo species on iron and neighboring nickel sites. The reduced electron density around Ni-O bonds creates in-gap states near the Fermi level. The magnitude of these in-gap states scales linearly with the OER performance and thus can be used as an activity descriptor. Contrary to literature we see the in-gap states even before electrochemical activation and conclude that they are a consequence of Ni-O-Fe motifs present already before anodization. Beyond 50% metal content the number of Ni-O-Fe motifs is decreasing again, resulting in an interval of 10-30% iron metal content to be optimal for the OER.
{"title":"The role of iron in the electronic configuration of mixed nickel iron oxides for the oxygen evolution reaction","authors":"Christopher Gort, Gustavo T. Feliciano, Alexander A. Auer, Bernhard Kaiser, W. Jaegermann, Jan Philipp Hofmann","doi":"10.1039/d5cp00386e","DOIUrl":"https://doi.org/10.1039/d5cp00386e","url":null,"abstract":"Nickel-based oxides are among the best performing catalysts for the alkaline O2 evolution reaction (OER). It has long been recognized that iron enhances the catalytic activity of nickel-based catalysts, though only recently intensive research has been done on the interplay between the two transition metals, leading to the excellent performance, surpassing that of either pure metal. It is still not clear how the electronic configuration in mixed metal compounds changes to enhance their catalytic activity for the OER. We carried out a systematic study of the electronic configuration of thin film mixed metal oxides Ni(1-x)FexOyHz with varying contents x of iron. In this investigation we employed X-ray absorption and resonant valence photoelectron spectroscopy (XAS and resPES) to gain knowledge on the changes induced in the electronic structure by introduction of iron, both before and after electrochemical activation. Based on density functional calculations we found iron species to induce a highly oxidizing environment that facilitates generation of oxo species on iron and neighboring nickel sites. The reduced electron density around Ni-O bonds creates in-gap states near the Fermi level. The magnitude of these in-gap states scales linearly with the OER performance and thus can be used as an activity descriptor. Contrary to literature we see the in-gap states even before electrochemical activation and conclude that they are a consequence of Ni-O-Fe motifs present already before anodization. Beyond 50% metal content the number of Ni-O-Fe motifs is decreasing again, resulting in an interval of 10-30% iron metal content to be optimal for the OER.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"24 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143862155","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
All-solid-state lithium-ion batteries (ASSLIBs) are anticipated to be the next generation of high-performance lithium batteries due to their enhanced safety and high energy density. However, the widespread application of ASSLIBs will lead to a significant increase in spent batteries, resulting in environmental pollution and resource depletion. Therefore, the development of environmentally friendly recycling methods for ASSLIBs is both urgent and critical. Low-melting mixture solvents (LoMMSs) are proposed by Professor Yu's research group at Tsinghua University in 2023 to facilitate the advancement of green solvents and green chemistry. Here, we utilized LoMMSs to leach metals from solid-state electrolytes (SSEs) of ASSILBs and apply the 55 anti-solvents method to recover metal ions from leachate. Results show that the leaching efficiency of Li is up to 92.5 % at the mild temperature of 80 oC within 24 h. The high Li leaching efficiency is ascribed to the coordination interaction. Furthermore, the Li leaching efficiency in large-scale applications shows minimal deviation from the optimal efficiency. This research provides valuable insights into the development of efficient, green, and mild recycling methods for SSEs in ASSLIBs.
{"title":"Green recovery of solid electrolytes from all-solid-state lithium-ion batteries by low-melting mixture solvents with tunable physical properties","authors":"Yu Chen, Xueqing Zhang, Chenyang Wang, Zhuojia Shi, Xihou Wang, Jiayi Dong, Yanlong Wang, Minghui Feng","doi":"10.1039/d4cp04684f","DOIUrl":"https://doi.org/10.1039/d4cp04684f","url":null,"abstract":"All-solid-state lithium-ion batteries (ASSLIBs) are anticipated to be the next generation of high-performance lithium batteries due to their enhanced safety and high energy density. However, the widespread application of ASSLIBs will lead to a significant increase in spent batteries, resulting in environmental pollution and resource depletion. Therefore, the development of environmentally friendly recycling methods for ASSLIBs is both urgent and critical. Low-melting mixture solvents (LoMMSs) are proposed by Professor Yu's research group at Tsinghua University in 2023 to facilitate the advancement of green solvents and green chemistry. Here, we utilized LoMMSs to leach metals from solid-state electrolytes (SSEs) of ASSILBs and apply the 55 anti-solvents method to recover metal ions from leachate. Results show that the leaching efficiency of Li is up to 92.5 % at the mild temperature of 80 oC within 24 h. The high Li leaching efficiency is ascribed to the coordination interaction. Furthermore, the Li leaching efficiency in large-scale applications shows minimal deviation from the optimal efficiency. This research provides valuable insights into the development of efficient, green, and mild recycling methods for SSEs in ASSLIBs.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"11 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143857479","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Flavio Siro Brigiano, Thomas Thevenet, ALEXIS MARKOVITS, Julia Contreras-Garcia, Alfonso San Miguel, Fabio Pietrucci
The precise tailoring of the atomic architecture of 2D carbon-based materials, which results in the modulation of their physical properties, promises to open new pathways for the design of technological devices in electronics, spintronics and energy storage. High-pressure conditions can lead to the synthesis of complex materials starting from multi-layer graphene, often relying on chemical transformations at the interface between carbon and pressure-transmitting media like water or alcohol. Unfortunately, the experimental characterization of molecular-scale mechanisms at interfaces is very challenging. On the other side, the sheer cost of ab initio simulations strongly limited, so far, the computational works in literature to simplified models that, often, do not capture the complexity of the materials and finite-temperature effects. In this work, we provide for the first time an extensive computational study of complex, realistic models of bilayer graphene-methanol interfaces at high pressure and finite temperature. Our simulations allow to gain fundamental insight on several questions raised from previous experimental works about structural, electronic and reactivity properties of this challenging material. The exploitation of state-of-the-art enhanced sampling techniques combined with topological electronic descriptors allowed to characterize barrier-activated functionalization processes, unveiling a major catalytic effect of carbon defects and pressure towards sp3 formation.
{"title":"Structural transitions at the bilayer graphene--methanol interface from ab initio molecular dynamics","authors":"Flavio Siro Brigiano, Thomas Thevenet, ALEXIS MARKOVITS, Julia Contreras-Garcia, Alfonso San Miguel, Fabio Pietrucci","doi":"10.1039/d5cp00605h","DOIUrl":"https://doi.org/10.1039/d5cp00605h","url":null,"abstract":"The precise tailoring of the atomic architecture of 2D carbon-based materials, which results in the modulation of their physical properties, promises to open new pathways for the design of technological devices in electronics, spintronics and energy storage. High-pressure conditions can lead to the synthesis of complex materials starting from multi-layer graphene, often relying on chemical transformations at the interface between carbon and pressure-transmitting media like water or alcohol. Unfortunately, the experimental characterization of molecular-scale mechanisms at interfaces is very challenging. On the other side, the sheer cost of ab initio simulations strongly limited, so far, the computational works in literature to simplified models that, often, do not capture the complexity of the materials and finite-temperature effects. In this work, we provide for the first time an extensive computational study of complex, realistic models of bilayer graphene-methanol interfaces at high pressure and finite temperature. Our simulations allow to gain fundamental insight on several questions raised from previous experimental works about structural, electronic and reactivity properties of this challenging material. The exploitation of state-of-the-art enhanced sampling techniques combined with topological electronic descriptors allowed to characterize barrier-activated functionalization processes, unveiling a major catalytic effect of carbon defects and pressure towards sp3 formation.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"35 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143857480","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Onni Veteläinen, Morsal Babayan, Lassi Pihlava, Abdul Rahman Abid, Antti Kivimäki, Edwin Kukk, Noelle Walsh, Samuli Urpelainen, Olle Björneholm, Marko Huttula, Matti Alatalo, Minna Patanen, Sergio Díaz-Tendero
Hydrogen migration is a ubiquitous phenomenon upon dissociation of organic molecules. Here we investigate the formation of a H3O+ fragment after core-level photoionization and Auger decay in aminobenzoic acid molecules - a process that requires the migration of at least two hydrogen atoms. Using photoelectron-photoion coincidence spectroscopy, the formation of a H3O+ fragment is observed to be more probable in ortho-aminobenzoic acid than in meta- and para-aminobenzoic acid. Energy-resolved Auger electron–photoion coincidences are measured for the ortho-isomer to investigate the internal energy dependence of the fragmentation channels, most notably of those producing H3O+. The corresponding fragmentation channels and their mechanisms are investigated by exploring the potential energy surface with ab initio quantum chemistry methods and molecular dynamics simulations. Excited-state modeling of dicationic ortho-aminobenzoic acid is used to interpret features in the Auger spectra and identify the electronic states contributing to the signals in the Auger electron photoion coincidence map. We show that populating low-energy excited states of the dication is sufficient to trigger hydrogen migration and produce H3O+ efficiently.
{"title":"Hydrogen migration reactions via low internal energy pathways in aminobenzoic acid dications","authors":"Onni Veteläinen, Morsal Babayan, Lassi Pihlava, Abdul Rahman Abid, Antti Kivimäki, Edwin Kukk, Noelle Walsh, Samuli Urpelainen, Olle Björneholm, Marko Huttula, Matti Alatalo, Minna Patanen, Sergio Díaz-Tendero","doi":"10.1039/d5cp00415b","DOIUrl":"https://doi.org/10.1039/d5cp00415b","url":null,"abstract":"Hydrogen migration is a ubiquitous phenomenon upon dissociation of organic molecules. Here we investigate the formation of a H<small><sub>3</sub></small>O<small><sup>+</sup></small> fragment after core-level photoionization and Auger decay in aminobenzoic acid molecules - a process that requires the migration of at least two hydrogen atoms. Using photoelectron-photoion coincidence spectroscopy, the formation of a H<small><sub>3</sub></small>O<small><sup>+</sup></small> fragment is observed to be more probable in ortho-aminobenzoic acid than in meta- and para-aminobenzoic acid. Energy-resolved Auger electron–photoion coincidences are measured for the ortho-isomer to investigate the internal energy dependence of the fragmentation channels, most notably of those producing H<small><sub>3</sub></small>O<small><sup>+</sup></small>. The corresponding fragmentation channels and their mechanisms are investigated by exploring the potential energy surface with ab initio quantum chemistry methods and molecular dynamics simulations. Excited-state modeling of dicationic ortho-aminobenzoic acid is used to interpret features in the Auger spectra and identify the electronic states contributing to the signals in the Auger electron photoion coincidence map. We show that populating low-energy excited states of the dication is sufficient to trigger hydrogen migration and produce H<small><sub>3</sub></small>O<small><sup>+</sup></small> efficiently.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"64 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143857478","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jocky C. K. Kung, Alan Kádek, Knut Kölbel, Steffi Bandelow, Sadia Bari, Jens Buck, Carl Caleman, Jan Commandeur, Tomislav Damjanović, Simon Dörner, Karim Fahmy, Lara Flacht, Johannes Heidemann, Khon Huynh, Janine-Denise Kopicki, Boris Krichel, Julia Lockhauserbäumer, Kristina Lorenzen, Yinfei Lu, Ronja Pogan, Jasmin Rehmann, Kira Schamoni-Kast, Schwob Lucas, Lutz Schweikhard, Sebastian Springer, Pamela H. W. Svensson, Florian Simke, Florian Trinter, Sven Toleikis, Thomas Kierspel, Charlotte Uetrecht
Gas-phase activation and dissociation studies of biomolecules, proteins and their non-covalent complexes using X-rays hold great promise for revealing new insights into the structure and function of biological samples. This is due to the unique properties of X-ray molecular interactions, such as site-specific and rapid ionization. In this perspective, we report and discuss the promise of first proof-of-principle studies of X-ray-induced dissociation of native biological samples ranging from small 17 kDa monomeric proteins up to large 808 kDa non-covalent protein assemblies conducted at a synchrotron (PETRA III) and a free-electron laser (FLASH2). A commercially available quadrupole time-of-flight mass spectrometer (Q-ToF2, Micromass/Waters), modified for high-mass analysis by MS Vision, was further adapted for integration with the open ports at the corresponding beamlines. The protein complexes were transferred natively into the gas phase via nano-electrospray ionization and subsequently probed by extreme ultraviolet (FLASH2) or soft X-ray (PETRA III) radiation, in either their folded state or following collision-induced activation in the gas phase. Depending on the size of the biomolecule and the activation method, protein fragmentation, dissociation, or enhanced ionization were observed. Additionally, an extension of the setup by ion mobility is described, which can serve as a powerful tool for structural separation of biomolecules prior to X-ray probing. The first experimental results are discussed in the broader context of current and upcoming X-ray sources, highlighting their potential for advancing structural biology in the future.
{"title":"X-ray Spectroscopy Meets Native Mass Spectrometry: Probing Gas-phase Protein Complexes","authors":"Jocky C. K. Kung, Alan Kádek, Knut Kölbel, Steffi Bandelow, Sadia Bari, Jens Buck, Carl Caleman, Jan Commandeur, Tomislav Damjanović, Simon Dörner, Karim Fahmy, Lara Flacht, Johannes Heidemann, Khon Huynh, Janine-Denise Kopicki, Boris Krichel, Julia Lockhauserbäumer, Kristina Lorenzen, Yinfei Lu, Ronja Pogan, Jasmin Rehmann, Kira Schamoni-Kast, Schwob Lucas, Lutz Schweikhard, Sebastian Springer, Pamela H. W. Svensson, Florian Simke, Florian Trinter, Sven Toleikis, Thomas Kierspel, Charlotte Uetrecht","doi":"10.1039/d5cp00604j","DOIUrl":"https://doi.org/10.1039/d5cp00604j","url":null,"abstract":"Gas-phase activation and dissociation studies of biomolecules, proteins and their non-covalent complexes using X-rays hold great promise for revealing new insights into the structure and function of biological samples. This is due to the unique properties of X-ray molecular interactions, such as site-specific and rapid ionization. In this perspective, we report and discuss the promise of first proof-of-principle studies of X-ray-induced dissociation of native biological samples ranging from small 17 kDa monomeric proteins up to large 808 kDa non-covalent protein assemblies conducted at a synchrotron (PETRA III) and a free-electron laser (FLASH2). A commercially available quadrupole time-of-flight mass spectrometer (Q-ToF2, Micromass/Waters), modified for high-mass analysis by MS Vision, was further adapted for integration with the open ports at the corresponding beamlines. The protein complexes were transferred natively into the gas phase via nano-electrospray ionization and subsequently probed by extreme ultraviolet (FLASH2) or soft X-ray (PETRA III) radiation, in either their folded state or following collision-induced activation in the gas phase. Depending on the size of the biomolecule and the activation method, protein fragmentation, dissociation, or enhanced ionization were observed. Additionally, an extension of the setup by ion mobility is described, which can serve as a powerful tool for structural separation of biomolecules prior to X-ray probing. The first experimental results are discussed in the broader context of current and upcoming X-ray sources, highlighting their potential for advancing structural biology in the future.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"28 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143857475","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Alexander Kanzow, Beppo Hartwig, Philipp Buschmann, Kevin G. Lengsfeld, Cara Marie Höhne, Joshua Sky Hoke, Finn Knüppe, Finn Louis Köster, Jakob Klaas van Spronsen, Jens-Uwe Grabow, donald mcnaughton, Daniel A Obenchain
Microwave spectra of citraconic anhydride and its tautomer itaconic anhydride have been recorded in a frequency range of 6 – 18 GHz. Both a- and b-type transitions were observed for both tautomers, while c-type transitions could only be observed for the E torsional symmetry state of citraconic anhydride. For both molecules, a molecular substitution structure, rS, was obtained by measurements of mono-substituted 13C isotopologues in natural abundance. For citraconic anhydride, 18O isotopologues were also observed and the V3 barrier to internal rotation has been determined at 326.5153(61) cm−1. In addition to the microwave spectra, a gas-phase study of isomerisation between the tautomers was carried out, which was assisted by theoretical transition state calculations, employing a variety of different density functionals as well as the wavefunction based Møller-Plesset perturbation theory, MP2, and coupled cluster methods, CCSD(T)-F12c and DCSD-F12b. These were also used to benchmark the experimentally determined rS structures and V3 barrier of rotation in citraconic anhydride. Via theoretical ground state vibrational calculations, semi-experimental equilibrium structure, rSE0→e, were derived for each theoretical method and were compared to the coupled cluster equilibrium structures, re. In addition, mass dependent r(1) m and r(2)m fits were conducted to obtain approximate re structures. Using the determined structures we can revise a previous study that misidentified citraconic anhydride as itaconic anhydride.
在 6 - 18 千兆赫的频率范围内记录了柠檬酸酐及其同系物衣康酸酐的微波光谱。在这两种同系物中都观察到了 a 型和 b 型转变，而只在柠檬酸酐的 E 扭对称态中观察到了 c 型转变。通过测量天然丰度的单取代 13C 同素异形体，获得了这两种分子的分子取代结构 rS。对于柠檬酸酐，还观测到了 18O 同素异形体，并确定了内旋转的 V3 屏障为 326.5153(61) cm-1。除了微波光谱之外，我们还对同系物之间的异构化进行了气相研究，并利用各种不同的密度函数、基于波函数的默勒-普莱塞特扰动理论 MP2 以及耦合簇方法 CCSD(T)-F12c 和 DCSD-F12b 对过渡态进行了理论计算。这些方法还被用于对实验确定的柠檬酸酐 rS 结构和 V3 旋转障碍进行基准测试。通过基态振动理论计算，我们得出了每种理论方法的半实验平衡结构 rSE0→e，并与耦合簇平衡结构 re 进行了比较。利用所确定的结构，我们可以修正之前将柠檬酸酐误认为衣康酸酐的研究。
{"title":"Tautomer identification troubles: The molecular structure of itaconic and citraconic anhydride revealed by rotational spectroscopy","authors":"Alexander Kanzow, Beppo Hartwig, Philipp Buschmann, Kevin G. Lengsfeld, Cara Marie Höhne, Joshua Sky Hoke, Finn Knüppe, Finn Louis Köster, Jakob Klaas van Spronsen, Jens-Uwe Grabow, donald mcnaughton, Daniel A Obenchain","doi":"10.1039/d5cp00389j","DOIUrl":"https://doi.org/10.1039/d5cp00389j","url":null,"abstract":"Microwave spectra of citraconic anhydride and its tautomer itaconic anhydride have been recorded in a frequency range of 6 – 18 GHz. Both a- and b-type transitions were observed for both tautomers, while c-type transitions could only be observed for the E torsional symmetry state of citraconic anhydride. For both molecules, a molecular substitution structure, rS, was obtained by measurements of mono-substituted 13C isotopologues in natural abundance. For citraconic anhydride, 18O isotopologues were also observed and the V3 barrier to internal rotation has been determined at 326.5153(61) cm−1. In addition to the microwave spectra, a gas-phase study of isomerisation between the tautomers was carried out, which was assisted by theoretical transition state calculations, employing a variety of different density functionals as well as the wavefunction based Møller-Plesset perturbation theory, MP2, and coupled cluster methods, CCSD(T)-F12c and DCSD-F12b. These were also used to benchmark the experimentally determined rS structures and V3 barrier of rotation in citraconic anhydride. Via theoretical ground state vibrational calculations, semi-experimental equilibrium structure, rSE0→e, were derived for each theoretical method and were compared to the coupled cluster equilibrium structures, re. In addition, mass dependent r(1) m and r(2)m fits were conducted to obtain approximate re structures. Using the determined structures we can revise a previous study that misidentified citraconic anhydride as itaconic anhydride.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"187 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143862160","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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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