Asymmetric architecture of AB-type block copolymers can induce additional spontaneous curvature to A/B interface, accordingly deflecting the phase boundaries. However, it is often difficult to determine or compare the asymmetric effects of different asymmetric architectures. In this work, we proposed to use the equivalent arm numbers nequ, which was originally defined as nequ = n/iÐ for ABn with unequal B-arms and iÐ being the intramolecular polydispersity of these B-arms, to quantify the asymmetric effect of various linear-hyperbranched copolymers. For each linear-hyperbranched copolymer, nequis estimated by matching its phase boundaries on the side with expanded spherical phase region with those of ABn with unequal B-arms but tunable iÐ. Our results suggest that the addition of B-blocks at the further location from the A-B joint point has less influence on nequ, i.e. the asymmetric effect, because these B-blocks can access more space. For the linear-dendrimer copolymers, nequ changes from 2 to about 3.8 when the overall generation number of the copolymer increases from 2 to 5. In other words, the asymmetric effect of these linear-dendrimer copolymers is intermediate between those of AB2 and AB4 miktoarm star copolymers. In brief, nequ can effectively describe the asymmetric effect on the interfacial curvature of complex asymmetric architectures.
{"title":"Effect of architectural asymmetry of hyperbranched block copolymers on their phase boundaries","authors":"Jiahao Shi, Qingshu Dong, Tao Yang, Weihua Li","doi":"10.1039/d4cp04814h","DOIUrl":"https://doi.org/10.1039/d4cp04814h","url":null,"abstract":"Asymmetric architecture of AB-type block copolymers can induce additional spontaneous curvature to A/B interface, accordingly deflecting the phase boundaries. However, it is often difficult to determine or compare the asymmetric effects of different asymmetric architectures. In this work, we proposed to use the equivalent arm numbers n<small><sub>equ</sub></small>, which was originally defined as n<small><sub>equ</sub></small> = n/iÐ for AB<small><sub>n</sub></small> with unequal B-arms and iÐ being the intramolecular polydispersity of these B-arms, to quantify the asymmetric effect of various linear-hyperbranched copolymers. For each linear-hyperbranched copolymer, nequis estimated by matching its phase boundaries on the side with expanded spherical phase region with those of AB<small><sub>n</sub></small> with unequal B-arms but tunable iÐ. Our results suggest that the addition of B-blocks at the further location from the A-B joint point has less influence on n<small><sub>equ</sub></small>, i.e. the asymmetric effect, because these B-blocks can access more space. For the linear-dendrimer copolymers, n<small><sub>equ</sub></small> changes from 2 to about 3.8 when the overall generation number of the copolymer increases from 2 to 5. In other words, the asymmetric effect of these linear-dendrimer copolymers is intermediate between those of AB<small><sub>2</sub></small> and AB<small><sub>4</sub></small> miktoarm star copolymers. In brief, n<small><sub>equ</sub></small> can effectively describe the asymmetric effect on the interfacial curvature of complex asymmetric architectures.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"67 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143538693","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}
The use of alcohol as hand sanitizer to prevent the spread of contamination of SARS-CoV-2 is known. In this work, a series of atomistic molecular dynamics (MD) simulations were carried out with the receptor-binding-domain (RBD) of the SARS-CoV-2 in different aqueous binary and ternary mixtures of concentrated ethanol, npropanol (n-pr), and isopropanol (iso-pr) solutions to elucidate the structural alteration of RBD at an ambient and elevated temperature and to understand RBD’s interactions with the host cellular receptor ACE2. Computation of several structural metrics like RMSD, Rg, and fraction of native contacts along with the construction of a 2D-free energy landscape suggests that among all the water-alcohol(s) solutions, the structural transition of RBD conformation was more pronounced in the water-etoh-iso-pr mixture at ambient conditions which further altered significantly and RBD adopted partially unfolded states at 350 K, as compared to the native form. We observed that the preferential exclusion of different alcohols from the RBD surface regulates the solvation features of RBD and hence the RBD-alcohol hydrogen bonds, which is one of the crucial factors that rupture RBD’s structure heterogeneously. The comparative study infers that relative to binary mixtures, the ternary solutions rupture the native RBD structure more effectively that was caused by the relative reduction in dynamics in the ternary mixture for the particular pair of hydrogen bonds arising from the hindered rotation of certain alcohol molecules. Our microscopic investigation identified that the specific binding zone binding zone of RBD and ACE2 were found to increase from the molecular docking study; this could prevent further transmission.
{"title":"Unraveling the impact of binary vs ternary alcohol solutions on the conformation and solvation of the SARS-CoV-2 receptor- binding domain","authors":"Rabiul Gazi, Madhurima Jana","doi":"10.1039/d4cp04402a","DOIUrl":"https://doi.org/10.1039/d4cp04402a","url":null,"abstract":"The use of alcohol as hand sanitizer to prevent the spread of contamination of SARS-CoV-2 is known. In this work, a series of atomistic molecular dynamics (MD) simulations were carried out with the receptor-binding-domain (RBD) of the SARS-CoV-2 in different aqueous binary and ternary mixtures of concentrated ethanol, npropanol (n-pr), and isopropanol (iso-pr) solutions to elucidate the structural alteration of RBD at an ambient and elevated temperature and to understand RBD’s interactions with the host cellular receptor ACE2. Computation of several structural metrics like RMSD, Rg, and fraction of native contacts along with the construction of a 2D-free energy landscape suggests that among all the water-alcohol(s) solutions, the structural transition of RBD conformation was more pronounced in the water-etoh-iso-pr mixture at ambient conditions which further altered significantly and RBD adopted partially unfolded states at 350 K, as compared to the native form. We observed that the preferential exclusion of different alcohols from the RBD surface regulates the solvation features of RBD and hence the RBD-alcohol hydrogen bonds, which is one of the crucial factors that rupture RBD’s structure heterogeneously. The comparative study infers that relative to binary mixtures, the ternary solutions rupture the native RBD structure more effectively that was caused by the relative reduction in dynamics in the ternary mixture for the particular pair of hydrogen bonds arising from the hindered rotation of certain alcohol molecules. Our microscopic investigation identified that the specific binding zone binding zone of RBD and ACE2 were found to increase from the molecular docking study; this could prevent further transmission.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"52 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143538689","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}
The spectral response at the interface between lithium-containing 1-ethyl-3-methyl-imidazolium bis(trifluoromethanesulfonyl)imide (EMIM-TFSI) and a gold electrode was investigated using electrochemical attenuated total reflection spectroscopy (EC-ATR) in the far-ultraviolet and infrared regions. At a negatively charged Au electrode within the cathodic limit, an increase in the EMIM cation signal and a decrease in the TFSI anion signal were observed for neat EMIM-TFSI, indicating the normal replacement of the TFSI anions by the EMIM cations. In contrast, an apparent decrease in the EMIM cation signal and an increase in the TFSI anion signal were observed, suggesting the replacement of the EMIM cation with a Li+ cation coordinated with TFSI anions. The ATR spectral responses were reversible in the electrode potential cycles, likely due to diffusion perpendicular to the electrode or the reorientation of the interfacial ionic liquid components. The surface-stabilized Li+ ions coordinated by the TFSI anions at the negatively charged Au electrode may restrict the direct interaction of the EMIM cation with the electrode, thereby reducing the reduction rate of the EMIM cation, and extending the cathodic limit upon the addition of the Li salt.
{"title":"Molecular insight into the dynamics at the lithium-containing ionic liquid/gold film electrode interface using electrochemical attenuated total reflection spectroscopies","authors":"Tomonori Kakinoki, Akihito Imanishi, Shinji Kondou, Ichiro Tanabe, Ken-ichi Fukui","doi":"10.1039/d4cp04831h","DOIUrl":"https://doi.org/10.1039/d4cp04831h","url":null,"abstract":"The spectral response at the interface between lithium-containing 1-ethyl-3-methyl-imidazolium bis(trifluoromethanesulfonyl)imide (EMIM-TFSI) and a gold electrode was investigated using electrochemical attenuated total reflection spectroscopy (EC-ATR) in the far-ultraviolet and infrared regions. At a negatively charged Au electrode within the cathodic limit, an increase in the EMIM cation signal and a decrease in the TFSI anion signal were observed for neat EMIM-TFSI, indicating the normal replacement of the TFSI anions by the EMIM cations. In contrast, an apparent decrease in the EMIM cation signal and an increase in the TFSI anion signal were observed, suggesting the replacement of the EMIM cation with a Li<small><sup>+</sup></small> cation coordinated with TFSI anions. The ATR spectral responses were reversible in the electrode potential cycles, likely due to diffusion perpendicular to the electrode or the reorientation of the interfacial ionic liquid components. The surface-stabilized Li<small><sup>+</sup></small> ions coordinated by the TFSI anions at the negatively charged Au electrode may restrict the direct interaction of the EMIM cation with the electrode, thereby reducing the reduction rate of the EMIM cation, and extending the cathodic limit upon the addition of the Li salt.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"5 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143538686","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}
Carlos Augusto Augusto Campos Roldán, Raphael Chattot, Pierre-Yves Blanchard, Deborah J. Jones, Sara Cavaliere
Platinum-based nanoalloys are considered as efficient electrocatalysts for the oxygen reduction reaction (ORR). However, in situ/operando measurements have revealed that key properties (e.g. induced strain, chemical composition, coordination environment, etc.) evolve significally during operation, hampering their effective implementation in fuel cells. In fact, recent studies have indicated that the impact of the early surface activation steps of Pt-based nanoalloys has been hitherto underestimated and are an important factor contributing to the loss of their electroactivity. In this short perspective, we highlight the need for in situ/operando characterization of Pt-based electrocatalysts during the initial operation steps in the ORR by discussing recent insights into their early degradation and evolution of their key properties during electrochemical characterization.
{"title":"Platinum-Based Nanoalloys for the Oxygen Reduction Reaction: Exposing the True Active Phase via In Situ/Operando Techniques","authors":"Carlos Augusto Augusto Campos Roldán, Raphael Chattot, Pierre-Yves Blanchard, Deborah J. Jones, Sara Cavaliere","doi":"10.1039/d4cp03665d","DOIUrl":"https://doi.org/10.1039/d4cp03665d","url":null,"abstract":"Platinum-based nanoalloys are considered as efficient electrocatalysts for the oxygen reduction reaction (ORR). However, in situ/operando measurements have revealed that key properties (e.g. induced strain, chemical composition, coordination environment, etc.) evolve significally during operation, hampering their effective implementation in fuel cells. In fact, recent studies have indicated that the impact of the early surface activation steps of Pt-based nanoalloys has been hitherto underestimated and are an important factor contributing to the loss of their electroactivity. In this short perspective, we highlight the need for in situ/operando characterization of Pt-based electrocatalysts during the initial operation steps in the ORR by discussing recent insights into their early degradation and evolution of their key properties during electrochemical characterization.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"30 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143546653","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}
Kazuhiro Iwamatsu, Gregory Holmbeck, Alejandro Ramos-Ballesteros, Stephanie Castro Baldivieso, Jacy K Conrad, Michael E Woods, William C. Phillips, Jay A Laverne, Simon M. Pimblott, James F. Wishart
Chromium (Cr) is a frequent constituent of the metal alloys proposed for molten salt nuclear reactor (MSR) applications, and is typically the least noble metal ion present. Consequently, chromium is preferentially corroded into molten salt solutions. The redox poise and redox cycling of chromium ions in the salt can greatly influence its corrosivity towards structural alloys, ultimately impacting the longevity of MSR systems. Radiation-induced chemistry is expected to play a significant role in determining the chromium oxidation state distribution during MSR operations. In the present research, electron pulse radiolysis techniques were employed to characterize the reactivity of Cr(II) and Cr(III) ions with primary radiolysis products in molten lithium chloride-potassium chloride (LiCl-KCl) eutectic over a temperature range of 400–600 °C. Both chromium oxidation states were found to rapidly react with the primary products of molten chloride salt radiolysis, i.e., the solvated electron (eS–) and the dichlorine radical anion (Cl2●–). For reactions with the (eS–), second-order rate coefficients (k) of k = (4.1 ± 0.2) and (6.1 ± 0.3) × 1010 M–1 s–1 at 400 °C for Cr(II) and Cr(III), respectively, were determined. Temperature-dependent measurements allowed for the derivation of activation parameters for electron capture by Cr(II) and Cr(III). Both chromium ions also react with (Cl2●–), k = (7.2 ± 0.3) and (1.4 ± 0.1) × 109 M–1 s–1 at 400 °C for Cr(II) and Cr(III), respectively.
{"title":"Kinetics of Radiation-induced Cr(II) and Cr(III) Redox Chemistry in Molten LiCl-KCl Eutectic","authors":"Kazuhiro Iwamatsu, Gregory Holmbeck, Alejandro Ramos-Ballesteros, Stephanie Castro Baldivieso, Jacy K Conrad, Michael E Woods, William C. Phillips, Jay A Laverne, Simon M. Pimblott, James F. Wishart","doi":"10.1039/d4cp04190a","DOIUrl":"https://doi.org/10.1039/d4cp04190a","url":null,"abstract":"Chromium (Cr) is a frequent constituent of the metal alloys proposed for molten salt nuclear reactor (MSR) applications, and is typically the least noble metal ion present. Consequently, chromium is preferentially corroded into molten salt solutions. The redox poise and redox cycling of chromium ions in the salt can greatly influence its corrosivity towards structural alloys, ultimately impacting the longevity of MSR systems. Radiation-induced chemistry is expected to play a significant role in determining the chromium oxidation state distribution during MSR operations. In the present research, electron pulse radiolysis techniques were employed to characterize the reactivity of Cr(II) and Cr(III) ions with primary radiolysis products in molten lithium chloride-potassium chloride (LiCl-KCl) eutectic over a temperature range of 400–600 °C. Both chromium oxidation states were found to rapidly react with the primary products of molten chloride salt radiolysis, i.e., the solvated electron (e<small><sub>S</sub></small><small><sup>–</sup></small>) and the dichlorine radical anion (Cl<small><sub>2</sub></small><small><sup>●–</sup></small>). For reactions with the (e<small><sub>S</sub></small><small><sup>–</sup></small>), second-order rate coefficients (<em>k</em>) of <em>k</em> = (4.1 ± 0.2) and (6.1 ± 0.3) × 10<small><sup>10</sup></small> M<small><sup>–1</sup></small> s<small><sup>–1</sup></small> at 400 °C for Cr(II) and Cr(III), respectively, were determined. Temperature-dependent measurements allowed for the derivation of activation parameters for electron capture by Cr(II) and Cr(III). Both chromium ions also react with (Cl<small><sub>2</sub></small><small><sup>●–</sup></small>), <em>k</em> = (7.2 ± 0.3) and (1.4 ± 0.1) × 10<small><sup>9</sup></small> M<small><sup>–1</sup></small> s<small><sup>–1</sup></small> at 400 °C for Cr(II) and Cr(III), respectively.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"32 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143538687","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}
This study investigates the spin-dependent transport properties of two different magnetic tunnel junctions (MTJs) with a slab with three Ni atomic layers: Ni(111)/Vacuum/Ni(111) and Ni(111)-{it h}-BN/{it h}-BN/Ni(111)-{it h}-BN. By density functional calculations combined with nonequilibrium Green’s function technique, we found that the Ni/Vacuum/Ni MTJ has a low TMR ratio of only 3.4%. However, when monolayer of {it h}-BN is epitaxially grown on the Ni(111) surface, the TMR ratio can be increased to 136.07% at equilibrium state. When a bias of [0, 100] mV is applied, the TMR ratios are greater than 100% in a wide voltage range. Furthermore, the MTJ exhibits a spin injection efficiency of 88.53% in the parallel magnetic configuration, which remains stable above 80% throughout the entire bias range. All these results indicate that the TMR and spin injection of the MTJs with freestanding Ni as the leads and vacuum as the tunneling barrier can be dramatically improved by epitaxially growing monolayer {it h}-BN on the surface of Ni(111). The length of the pure {it h}-BN region can affect the TMR performance of the device. Specifically, TMR tends to decrease with the length of central barrier, but it can still be greater than 100% within a certain bias range. Meanwhile, the spin injection of the MTJs is hardly affected and can be maintained above 80%, indicating high spin injection efficiency. The findings of this study have significant implications in the understanding TMR and spin injection mechanisms in MTJs and the design of TMR devices.
{"title":"Ab initio study on enhancement of tunneling magnetoresistance and spin injection in Ni/Vacuum/Ni magnetic tunnel junctions by h-BN stacking","authors":"Ziqi Han, Chun-sheng Liu, Xiaohong Zheng, Dayong Liu, Weiyang Wang, Yushen Liu","doi":"10.1039/d4cp04428b","DOIUrl":"https://doi.org/10.1039/d4cp04428b","url":null,"abstract":"This study investigates the spin-dependent transport properties of two different magnetic tunnel junctions (MTJs) with a slab with three Ni atomic layers: Ni(111)/Vacuum/Ni(111) and Ni(111)-{it h}-BN/{it h}-BN/Ni(111)-{it h}-BN. By density functional calculations combined with nonequilibrium Green’s function technique, we found that the Ni/Vacuum/Ni MTJ has a low TMR ratio of only 3.4%. However, when monolayer of {it h}-BN is epitaxially grown on the Ni(111) surface, the TMR ratio can be increased to 136.07% at equilibrium state. When a bias of [0, 100] mV is applied, the TMR ratios are greater than 100% in a wide voltage range. Furthermore, the MTJ exhibits a spin injection efficiency of 88.53% in the parallel magnetic configuration, which remains stable above 80% throughout the entire bias range. All these results indicate that the TMR and spin injection of the MTJs with freestanding Ni as the leads and vacuum as the tunneling barrier can be dramatically improved by epitaxially growing monolayer {it h}-BN on the surface of Ni(111). The length of the pure {it h}-BN region can affect the TMR performance of the device. Specifically, TMR tends to decrease with the length of central barrier, but it can still be greater than 100% within a certain bias range. Meanwhile, the spin injection of the MTJs is hardly affected and can be maintained above 80%, indicating high spin injection efficiency. The findings of this study have significant implications in the understanding TMR and spin injection mechanisms in MTJs and the design of TMR devices.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"83 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143538691","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}
To investigate the radical-site-dependence of the exchange coupling in bisnitroxides, we have synthesized novel three acridan-based diradicals, tert-butyl nitroxide groups at the 2,7-, 2,6- and 3,6-positions of 10-benzyl-10’-methyl-9,9’(10H,10’H)spirobiacridine (1-pp, 1-mp and 1-mm, respectively). Theoretical and experimental magnetic studies indicate that 1-pp and 1-mm exhibit a singlet ground state, while 1-mp exhibits a triplet ground state. These spin states can be explained by the spin polarization mechanism. Quantitative analysis revealed a difference in the magnitude of the exchange coupling constants between 1-pp and 1-mm owing to their local spin structures corresponding to 1,4- and 1,3-phenylene diradical motifs (Kekulé and non-Kekulé structures, respectively).
{"title":"Radical-Site-Dependent Exchange Interactions in Acridane-Based Bisnitroxides","authors":"Yuta Takenouchi, Takuya Kanetomo, Masaya Enomoto","doi":"10.1039/d4cp04393f","DOIUrl":"https://doi.org/10.1039/d4cp04393f","url":null,"abstract":"To investigate the radical-site-dependence of the exchange coupling in bisnitroxides, we have synthesized novel three acridan-based diradicals, tert-butyl nitroxide groups at the 2,7-, 2,6- and 3,6-positions of 10-benzyl-10’-methyl-9,9’(10<em>H</em>,10’<em>H</em>)spirobiacridine (<strong>1-pp</strong>, <strong>1-mp</strong> and <strong>1-mm</strong>, respectively). Theoretical and experimental magnetic studies indicate that <strong>1-pp</strong> and <strong>1-mm</strong> exhibit a singlet ground state, while <strong>1-mp</strong> exhibits a triplet ground state. These spin states can be explained by the spin polarization mechanism. Quantitative analysis revealed a difference in the magnitude of the exchange coupling constants between <strong>1-pp</strong> and <strong>1-mm</strong> owing to their local spin structures corresponding to 1,4- and 1,3-phenylene diradical motifs (Kekulé and non-Kekulé structures, respectively).","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"211 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143538685","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}
Bagrat Shainyan, Alexey Eroshin, Sergey A. Shlykov
A gas-phase electron diffraction analysis combined with mass-spectrometry (GED/MS) of (2R,9S)-trans-2,9-diiodo-13-(triflyl)-13-azabicyclo[8.2.1]tridec-5-ene 5 was performed and the results compared with the earlier studied by GED/MS and X-ray analysis triflamide derivatives, that is 3,7,9-tris(triflyl)-3,7,9-triazabicyclo[3.3.1]nonane 2, 6-iodo-3-(triflamidomethyl)-4-triflyl-1,4,2,7-oxazadisilepane 3, and2,2,4,4-tetramethyl-6,8-bis(triflyl)-3-oxa-6,8-diaza-2,4-disilabicyclo[3.2.2]nonane 4. In addition, the first GED study was performed for triflamide CF3SO2NH2, 6, for which the X-ray structure has also been studied. Two conformers of 5 with the oppositely distorted dihedral angles in the five-membered ring were proved in gas phase, and, after careful analysis, also in the crystal. Very low barrier to interconversion (1.7 kcal/mol) and energy difference (0.6 kcal/mol) were calculated. In gas, the S–N and S–C bonds are longer than in the crystal, clearly indicating tightening due to crystal packing effects.
{"title":"Heterocyclic products of oxidative triflamidation of unsaturated compounds: gas-phase vs. crystal structure","authors":"Bagrat Shainyan, Alexey Eroshin, Sergey A. Shlykov","doi":"10.1039/d4cp04855e","DOIUrl":"https://doi.org/10.1039/d4cp04855e","url":null,"abstract":"A gas-phase electron diffraction analysis combined with mass-spectrometry (GED/MS) of (2R,9S)-trans-2,9-diiodo-13-(triflyl)-13-azabicyclo[8.2.1]tridec-5-ene 5 was performed and the results compared with the earlier studied by GED/MS and X-ray analysis triflamide derivatives, that is 3,7,9-tris(triflyl)-3,7,9-triazabicyclo[3.3.1]nonane 2, 6-iodo-3-(triflamidomethyl)-4-triflyl-1,4,2,7-oxazadisilepane 3, and2,2,4,4-tetramethyl-6,8-bis(triflyl)-3-oxa-6,8-diaza-2,4-disilabicyclo[3.2.2]nonane 4. In addition, the first GED study was performed for triflamide CF3SO2NH2, 6, for which the X-ray structure has also been studied. Two conformers of 5 with the oppositely distorted dihedral angles in the five-membered ring were proved in gas phase, and, after careful analysis, also in the crystal. Very low barrier to interconversion (1.7 kcal/mol) and energy difference (0.6 kcal/mol) were calculated. In gas, the S–N and S–C bonds are longer than in the crystal, clearly indicating tightening due to crystal packing effects.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"29 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143532843","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}
Marco Marino, Gonzalo Rivero Carracedo, Andrey Rybakov, José J. Baldoví, Guido Fratesi
Magnonics is a rapidly growing field that is nowadays broadly recognized as a paradigm shift for information and communication technologies. In this context, antiferromagnetic materials are particularly relevant due to the lack of stray fields and their faster dynamics, with frequencies in the THz range and longer spin relaxation times. Herein, we investigate the chemical tuning of magnons in a prototypical antiferromagnetic transition metal oxide through the creation of a hybrid heterostructure formed by an Fe-phthalocyanine layer over a NiO(001) substrate. Our first-principles calculations for the hybrid material allow us to evaluate the effect of the adsorbed molecules on the electronic structure, charge transfer and magnetic exchange couplings of NiO. In particular, we observe an electron density flow from the O towards the Ni atoms in the substrate, and from the O atoms towards the molecule at the interface. As a result, the magnetic couplings are enhanced by 7.7% at the surface, accompanied by a decrease by 19.1% in the layer below the surface. Interestingly, our results predict a shift of the magnon frequencies by ~10 meV in the optical branch. This work provides a new step towards the design of molecular controlled magnetic materials for magnonic applications.
{"title":"Chemical Tuning of Magnons in NiO(001) by Fe-Phthalocyanine Adsorption","authors":"Marco Marino, Gonzalo Rivero Carracedo, Andrey Rybakov, José J. Baldoví, Guido Fratesi","doi":"10.1039/d4cp04547e","DOIUrl":"https://doi.org/10.1039/d4cp04547e","url":null,"abstract":"Magnonics is a rapidly growing field that is nowadays broadly recognized as a paradigm shift for information and communication technologies. In this context, antiferromagnetic materials are particularly relevant due to the lack of stray fields and their faster dynamics, with frequencies in the THz range and longer spin relaxation times. Herein, we investigate the chemical tuning of magnons in a prototypical antiferromagnetic transition metal oxide through the creation of a hybrid heterostructure formed by an Fe-phthalocyanine layer over a NiO(001) substrate. Our first-principles calculations for the hybrid material allow us to evaluate the effect of the adsorbed molecules on the electronic structure, charge transfer and magnetic exchange couplings of NiO. In particular, we observe an electron density flow from the O towards the Ni atoms in the substrate, and from the O atoms towards the molecule at the interface. As a result, the magnetic couplings are enhanced by 7.7% at the surface, accompanied by a decrease by 19.1% in the layer below the surface. Interestingly, our results predict a shift of the magnon frequencies by ~10 meV in the optical branch. This work provides a new step towards the design of molecular controlled magnetic materials for magnonic applications.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"67 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143532841","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}
Ke Xiao, Xiaohui Shi, Xingyuan Zhang, Qingming Ping, Lulu Du
Fe4N with the high curie temperature, large saturation magnetization and good stability has been widely used in spintronic devices. However, the in-plane magnetic anisotropy of Fe4N limits its further developments in the next-generation spintronic devices. Element substitution is an effective method to improve the magnetic properties of Fe4N. Here, the electronic structures and magnetic properties of ternary iron nitrides MxFe4-xN (x = 1 and 3, M = paramagnetic, antiferromagnetic, ferromagnetic, or heavy metal element) are investigated by first-principles calculations. The magnetic moments of Gd3FefN (21.22 μB) are 2.14 times larger than that of Fe4N (9.89 μB). Due to the antiferromagnetic coupling or low spin state, the total magnetic moments of 0 μB occur in Cr3FefN, YcFe3N, and Y3FefN. The spin polarization in Cu3FecN (76.1%), PtfFe3N (68.4%), and PtcFe3N (65.5%) are 1.59 and 1.42, and 1.37 times larger than that of Fe4N (47.9%). In addition, the tendence from perpendicular magnetic anisotropy (PMA) to in-plane magnetic anisotropy (IMA) in MfFe3N and from IMA to PMA in M3FefN is dependent to the increase the number of M. These novel magnetic properties provide a new avenue for Fe4N in next-generation spintronic devices with high density, low energy consumption, and high speed.
{"title":"Emergence of the novel magnetic properties in ternary iron nitrides toward spintronics: first-principles calculations","authors":"Ke Xiao, Xiaohui Shi, Xingyuan Zhang, Qingming Ping, Lulu Du","doi":"10.1039/d5cp00405e","DOIUrl":"https://doi.org/10.1039/d5cp00405e","url":null,"abstract":"Fe4N with the high curie temperature, large saturation magnetization and good stability has been widely used in spintronic devices. However, the in-plane magnetic anisotropy of Fe4N limits its further developments in the next-generation spintronic devices. Element substitution is an effective method to improve the magnetic properties of Fe4N. Here, the electronic structures and magnetic properties of ternary iron nitrides MxFe4-xN (x = 1 and 3, M = paramagnetic, antiferromagnetic, ferromagnetic, or heavy metal element) are investigated by first-principles calculations. The magnetic moments of Gd3FefN (21.22 μB) are 2.14 times larger than that of Fe4N (9.89 μB). Due to the antiferromagnetic coupling or low spin state, the total magnetic moments of 0 μB occur in Cr3FefN, YcFe3N, and Y3FefN. The spin polarization in Cu3FecN (76.1%), PtfFe3N (68.4%), and PtcFe3N (65.5%) are 1.59 and 1.42, and 1.37 times larger than that of Fe4N (47.9%). In addition, the tendence from perpendicular magnetic anisotropy (PMA) to in-plane magnetic anisotropy (IMA) in MfFe3N and from IMA to PMA in M3FefN is dependent to the increase the number of M. These novel magnetic properties provide a new avenue for Fe4N in next-generation spintronic devices with high density, low energy consumption, and high speed.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"49 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143532844","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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