ACS Physical Chemistry Au最新文献

{"title":"Crystal Lattice-Induced Stress modulates Photoinduced Jahn-Teller Distortion Dynamics.","authors":"Vandana Tiwari, Marcus Gallagher-Jones, Hyein Hwang, Hong-Guang Duan, Angus I Kirkland, R J Dwayne Miller, Ajay Jha","doi":"10.1021/acsphyschemau.4c00047","DOIUrl":"10.1021/acsphyschemau.4c00047","url":null,"abstract":"<p><p>Efficient photoredox chemical transformations are essential to the development of novel, cost-effective, and environmentally friendly synthetic methodologies. The concept of the entatic state in bioinorganic catalysis proposes that a preorganized structural configuration can reduce the energy barriers associated with chemical reactions. This concept provides one of the guiding principles to enhance catalytic efficiency by maintaining high-energy conformations close to the reaction's transition state. Copper(I)-based photocatalysts, recognized for their low toxicity and highly negative oxidation potentials, are of particular interest in entasis studies. In this study, we explore the impact of entasis caused by stress induced by the surrounding lattice on the excited state dynamics of a prototypical copper(I)-based photocatalyst in a single crystal form. Using femtosecond broadband transient absorption spectroscopy, we show that triplet state formation from the entactic state is faster (∼3.9 ps) in crystals compared with solution (∼11.3 ps). The observed faster intersystem crossing in crystals hints toward the possible existence of distorted square planar geometry with higher spin-orbit coupling at the minima of the S₁ state. We further discuss the influence of entasis on vibrationally coherent photoinduced Jahn-Teller distortions. Our findings reveal the photophysical properties of the copper complex under lattice-induced stress, which can be extended to enhance the broader applicability of the entatic state concept in other transition metal systems. Understanding how environmental stress-induced geometric constraints within crystal lattices affect photochemical behavior opens avenues for designing more efficient photocatalytic systems based on transition metals, potentially enhancing their applicability to sustainable chemical synthesis.</p>","PeriodicalId":29796,"journal":{"name":"ACS Physical Chemistry Au","volume":"4 6","pages":"660-668"},"PeriodicalIF":3.7,"publicationDate":"2024-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11613236/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142780732","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Crystal Lattice-Induced Stress modulates Photoinduced Jahn–Teller Distortion Dynamics","authors":"Vandana Tiwari,&nbsp;Marcus Gallagher-Jones,&nbsp;Hyein Hwang,&nbsp;Hong-Guang Duan,&nbsp;Angus I. Kirkland,&nbsp;R. J. Dwayne Miller* and Ajay Jha*,&nbsp;","doi":"10.1021/acsphyschemau.4c0004710.1021/acsphyschemau.4c00047","DOIUrl":"https://doi.org/10.1021/acsphyschemau.4c00047https://doi.org/10.1021/acsphyschemau.4c00047","url":null,"abstract":"<p >Efficient photoredox chemical transformations are essential to the development of novel, cost-effective, and environmentally friendly synthetic methodologies. The concept of the entatic state in bioinorganic catalysis proposes that a preorganized structural configuration can reduce the energy barriers associated with chemical reactions. This concept provides one of the guiding principles to enhance catalytic efficiency by maintaining high-energy conformations close to the reaction’s transition state. Copper(I)-based photocatalysts, recognized for their low toxicity and highly negative oxidation potentials, are of particular interest in entasis studies. In this study, we explore the impact of entasis caused by stress induced by the surrounding lattice on the excited state dynamics of a prototypical copper(I)-based photocatalyst in a single crystal form. Using femtosecond broadband transient absorption spectroscopy, we show that triplet state formation from the entactic state is faster (∼3.9 ps) in crystals compared with solution (∼11.3 ps). The observed faster intersystem crossing in crystals hints toward the possible existence of distorted square planar geometry with higher spin–orbit coupling at the minima of the S₁ state. We further discuss the influence of entasis on vibrationally coherent photoinduced Jahn–Teller distortions. Our findings reveal the photophysical properties of the copper complex under lattice-induced stress, which can be extended to enhance the broader applicability of the entatic state concept in other transition metal systems. Understanding how environmental stress-induced geometric constraints within crystal lattices affect photochemical behavior opens avenues for designing more efficient photocatalytic systems based on transition metals, potentially enhancing their applicability to sustainable chemical synthesis.</p>","PeriodicalId":29796,"journal":{"name":"ACS Physical Chemistry Au","volume":"4 6","pages":"660–668 660–668"},"PeriodicalIF":3.7,"publicationDate":"2024-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.acs.org/doi/epdf/10.1021/acsphyschemau.4c00047","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142713585","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Roundabout Mechanism of Ion–Molecule Nucleophilic Substitution Reactions","authors":"Xiangyu Wu,&nbsp;Fei Ying,&nbsp;Hongyi Wang,&nbsp;Li Yang,&nbsp;Jiaxu Zhang and Jing Xie*,&nbsp;","doi":"10.1021/acsphyschemau.4c0006110.1021/acsphyschemau.4c00061","DOIUrl":"https://doi.org/10.1021/acsphyschemau.4c00061https://doi.org/10.1021/acsphyschemau.4c00061","url":null,"abstract":"<p >Roundabout (RA) is an important indirect mechanism for gas-phase X^– + CH₃Y → XCH₃ + Y^– S_N2 reactions at a high collision energy. It refers to the rotation of the CH₃-group by half or multiple circles upon the collision of incoming nucleophiles before substitution takes place. The RA mechanism was first discovered in the Cl^– + CH₃I S_N2 reaction to explain the energy transfer observed in crossed molecular beam imaging experiments in 2008. Since then, the RA mechanism and its variants have been observed not only in multiple C-centered S_N2 reactions, but also in N-centered S_N2 reactions, proton transfer reactions, and elimination reactions. This work reviewed recent studies on the RA mechanism and summarized the characteristics of RA mechanisms in terms of variant types, product energy partitioning, and product velocity scattering angle distribution. RA mechanisms usually happen at small impact parameters and tend to couple with other mechanisms at relatively low collision energy, and the available energy of roundabout trajectories is primarily partitioned to internal energy. Factors that affect the importance of the RA mechanism were analyzed, including the type of leaving group and nucleophile, collision energy, and microsolvation. A massive leaving group and relatively high collision energy are prerequisite for the occurrence of the roundabout mechanism. Interestingly, when reacting with CH₃I, the importance of RA mechanisms follows an order of Cl^– &gt; HO^– &gt; F^–, and such a nucleophile dependence was attributed to the difference in proton affinity and size of the nucleophile.</p>","PeriodicalId":29796,"journal":{"name":"ACS Physical Chemistry Au","volume":"4 6","pages":"581–592 581–592"},"PeriodicalIF":3.7,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.acs.org/doi/epdf/10.1021/acsphyschemau.4c00061","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142713738","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Roundabout Mechanism of Ion–Molecule Nucleophilic Substitution Reactions","authors":"Xiangyu Wu, Fei Ying, Hongyi Wang, Li Yang, Jiaxu Zhang, Jing Xie","doi":"10.1021/acsphyschemau.4c00061","DOIUrl":"https://doi.org/10.1021/acsphyschemau.4c00061","url":null,"abstract":"Roundabout (RA) is an important indirect mechanism for gas-phase X^– + CH₃Y → XCH₃ + Y^– S_N2 reactions at a high collision energy. It refers to the rotation of the CH₃-group by half or multiple circles upon the collision of incoming nucleophiles before substitution takes place. The RA mechanism was first discovered in the Cl^– + CH₃I S_N2 reaction to explain the energy transfer observed in crossed molecular beam imaging experiments in 2008. Since then, the RA mechanism and its variants have been observed not only in multiple C-centered S_N2 reactions, but also in N-centered S_N2 reactions, proton transfer reactions, and elimination reactions. This work reviewed recent studies on the RA mechanism and summarized the characteristics of RA mechanisms in terms of variant types, product energy partitioning, and product velocity scattering angle distribution. RA mechanisms usually happen at small impact parameters and tend to couple with other mechanisms at relatively low collision energy, and the available energy of roundabout trajectories is primarily partitioned to internal energy. Factors that affect the importance of the RA mechanism were analyzed, including the type of leaving group and nucleophile, collision energy, and microsolvation. A massive leaving group and relatively high collision energy are prerequisite for the occurrence of the roundabout mechanism. Interestingly, when reacting with CH₃I, the importance of RA mechanisms follows an order of Cl^– &gt; HO^– &gt; F^–, and such a nucleophile dependence was attributed to the difference in proton affinity and size of the nucleophile.","PeriodicalId":29796,"journal":{"name":"ACS Physical Chemistry Au","volume":"44 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142256285","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ultrafast Spin Relaxation of Charge Carriers in Strongly Quantum Confined Methylammonium Lead Bromide Perovskite Magic-Sized Clusters","authors":"David C. Zeitz,&nbsp;Vivien L. Cherrette,&nbsp;Sarah A. Creech,&nbsp;Yan Li,&nbsp;Yuan Ping and Jin Z. Zhang*,&nbsp;","doi":"10.1021/acsphyschemau.4c0005110.1021/acsphyschemau.4c00051","DOIUrl":"https://doi.org/10.1021/acsphyschemau.4c00051https://doi.org/10.1021/acsphyschemau.4c00051","url":null,"abstract":"<p >Spin relaxation of charge carriers in strongly quantum confined perovskite magic-sized clusters has been probed, for the first time, by using polarization-controlled femtosecond transient absorption (fs-TA) spectroscopy. Fs-TA measurements with a circularly polarized pump and probe allowed for the determination of the exciton spin relaxation lifetime (∼1.5 ps) at room temperature based on the dynamics of a photoinduced absorption (PIA) feature peaked at 458 nm. This spin lifetime is shorter than that of perovskite quantum dots (PQDs) with a larger size, and the results suggest that exciton confinement and defects likely play a more important role in these strongly quantum confined magic-sized clusters with a larger surface-to-volume ratio.</p>","PeriodicalId":29796,"journal":{"name":"ACS Physical Chemistry Au","volume":"4 6","pages":"610–614 610–614"},"PeriodicalIF":3.7,"publicationDate":"2024-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.acs.org/doi/epdf/10.1021/acsphyschemau.4c00051","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142719287","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ultrafast Spin Relaxation of Charge Carriers in Strongly Quantum Confined Methylammonium Lead Bromide Perovskite Magic-Sized Clusters","authors":"David C. Zeitz, Vivien L. Cherrette, Sarah A. Creech, Yan Li, Yuan Ping, Jin Z. Zhang","doi":"10.1021/acsphyschemau.4c00051","DOIUrl":"https://doi.org/10.1021/acsphyschemau.4c00051","url":null,"abstract":"Spin relaxation of charge carriers in strongly quantum confined perovskite magic-sized clusters has been probed, for the first time, by using polarization-controlled femtosecond transient absorption (fs-TA) spectroscopy. Fs-TA measurements with a circularly polarized pump and probe allowed for the determination of the exciton spin relaxation lifetime (∼1.5 ps) at room temperature based on the dynamics of a photoinduced absorption (PIA) feature peaked at 458 nm. This spin lifetime is shorter than that of perovskite quantum dots (PQDs) with a larger size, and the results suggest that exciton confinement and defects likely play a more important role in these strongly quantum confined magic-sized clusters with a larger surface-to-volume ratio.","PeriodicalId":29796,"journal":{"name":"ACS Physical Chemistry Au","volume":"203 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142256287","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Direct Detection of Bound Water in Hydrated Powders of Lysozyme by Differential Scanning Calorimetry","authors":"Judith Peters*,&nbsp;Karin Kornmueller,&nbsp;Rim Dannaoui,&nbsp;Ejona Syla and Annalisa Pastore*,&nbsp;","doi":"10.1021/acsphyschemau.4c0002910.1021/acsphyschemau.4c00029","DOIUrl":"https://doi.org/10.1021/acsphyschemau.4c00029https://doi.org/10.1021/acsphyschemau.4c00029","url":null,"abstract":"<p >While exploring the behavior of lysozyme powders at different percentages of rehydration by differential scanning calorimetry, we noticed a small peak persistently on the left of the melting point of bulk water, which, when heating up the system, was always around −10 °C. The intensity of the transition was maximal at 160% rehydration and disappeared at higher values. By comparing the premelting peak properties in H₂O and D₂O, we attributed it to freezable water bound on the protein surface. This is the first time that such an observation has been reported.</p>","PeriodicalId":29796,"journal":{"name":"ACS Physical Chemistry Au","volume":"4 6","pages":"593–597 593–597"},"PeriodicalIF":3.7,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.acs.org/doi/epdf/10.1021/acsphyschemau.4c00029","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142713736","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Direct Detection of Bound Water in Hydrated Powders of Lysozyme by Differential Scanning Calorimetry","authors":"Judith Peters, Karin Kornmueller, Rim Dannaoui, Ejona Syla, Annalisa Pastore","doi":"10.1021/acsphyschemau.4c00029","DOIUrl":"https://doi.org/10.1021/acsphyschemau.4c00029","url":null,"abstract":"While exploring the behavior of lysozyme powders at different percentages of rehydration by differential scanning calorimetry, we noticed a small peak persistently on the left of the melting point of bulk water, which, when heating up the system, was always around −10 °C. The intensity of the transition was maximal at 160% rehydration and disappeared at higher values. By comparing the premelting peak properties in H₂O and D₂O, we attributed it to freezable water bound on the protein surface. This is the first time that such an observation has been reported.","PeriodicalId":29796,"journal":{"name":"ACS Physical Chemistry Au","volume":"69 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142219238","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"GO@β-Ag2MoO4 Composite: One-Step Synthesis, Characterization, and Photocatalytic Performance against RhB Dye","authors":"Pedro Hyug de Almeida da Silva,&nbsp;Dalete Araújo de Souza,&nbsp;Rubens Lucas de Freitas Filho,&nbsp;Ana Paula de Carvalho Teixeira,&nbsp;Rochel Montero Lago,&nbsp;Walter Ricardo Brito,&nbsp;Edgar Alves Araújo Junior,&nbsp;Litiko Lopes Takeno,&nbsp;Francimauro Sousa Morais,&nbsp;José Fábio de Lima Nascimento,&nbsp;Yurimiler Leyet Ruiz,&nbsp;Libertalamar Brilhalva Saraiva and Francisco Xavier Nobre*,&nbsp;","doi":"10.1021/acsphyschemau.4c0003810.1021/acsphyschemau.4c00038","DOIUrl":"https://doi.org/10.1021/acsphyschemau.4c00038https://doi.org/10.1021/acsphyschemau.4c00038","url":null,"abstract":"<p >The combination of materials to improve properties of interest has become one of the strategies widely used for numerous applications, including new catalysts, over the last few decades. In this study, silver molybdate (β-Ag₂MoO₄) microcrystals were efficiently obtained by the hydrothermal method, obtaining composites with different amounts of graphene oxide (GO) (1, 2.5, 5, 7.5, and 10%, w/w) using the conventional hydrothermal method. The incorporation of GO on silver molybdate was confirmed by X-ray diffraction (XRD) and Raman spectroscopy, where the vibrational modes and crystallographic planes characteristic of the materials of interest were highlighted. The images collected by scanning electron microscopy (SEM) revealed the occurrence of plate-shaped structures (shells) anchored to the surface of the silver molybdate microcrystals (core). The optical properties showed that the materials presented <i>E</i>_gap between 3.34 and 3.39 eV, where the sample with 7.5% of GO (GO@β-AgMo_7.5) was the one that presented energy for the conduction band, largely favorable to the formation of superoxide radicals through the photoexcitation process of electrons. The catalytic tests demonstrated that, among the samples obtained in this study, the sample with 7.5% of GO (GO@β-AgMo_7.5) exhibits superior photocatalytic performance against the dye rhodamine B (RhB) in an aqueous medium. Thus, the kinetics constant for photolysis (absence of catalysts) and for the sample β-AgMo and the sample with 7.5% of GO (GO@β-AgMo_7.5) are 0.38 × 10^–3, 12 × 10^–3, and 23.72 × 10^–3 min^–1, respectively. Therefore, it is 62.5 times more efficient in the degradation of the RhB dye, which confirms the promising photocatalytic properties of the obtained composite.</p>","PeriodicalId":29796,"journal":{"name":"ACS Physical Chemistry Au","volume":"4 6","pages":"632–646 632–646"},"PeriodicalIF":3.7,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.acs.org/doi/epdf/10.1021/acsphyschemau.4c00038","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142719285","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"GO@β-Ag2MoO4 Composite: One-Step Synthesis, Characterization, and Photocatalytic Performance against RhB Dye","authors":"Pedro Hyug de Almeida da Silva, Dalete Araújo de Souza, Rubens Lucas de Freitas Filho, Ana Paula de Carvalho Teixeira, Rochel Montero Lago, Walter Ricardo Brito, Edgar Alves Araújo Junior, Litiko Lopes Takeno, Francimauro Sousa Morais, José Fábio de Lima Nascimento, Yurimiler Leyet Ruiz, Libertalamar Brilhalva Saraiva, Francisco Xavier Nobre","doi":"10.1021/acsphyschemau.4c00038","DOIUrl":"https://doi.org/10.1021/acsphyschemau.4c00038","url":null,"abstract":"The combination of materials to improve properties of interest has become one of the strategies widely used for numerous applications, including new catalysts, over the last few decades. In this study, silver molybdate (β-Ag₂MoO₄) microcrystals were efficiently obtained by the hydrothermal method, obtaining composites with different amounts of graphene oxide (GO) (1, 2.5, 5, 7.5, and 10%, w/w) using the conventional hydrothermal method. The incorporation of GO on silver molybdate was confirmed by X-ray diffraction (XRD) and Raman spectroscopy, where the vibrational modes and crystallographic planes characteristic of the materials of interest were highlighted. The images collected by scanning electron microscopy (SEM) revealed the occurrence of plate-shaped structures (shells) anchored to the surface of the silver molybdate microcrystals (core). The optical properties showed that the materials presented <i>E</i>_gap between 3.34 and 3.39 eV, where the sample with 7.5% of GO (GO@β-AgMo_7.5) was the one that presented energy for the conduction band, largely favorable to the formation of superoxide radicals through the photoexcitation process of electrons. The catalytic tests demonstrated that, among the samples obtained in this study, the sample with 7.5% of GO (GO@β-AgMo_7.5) exhibits superior photocatalytic performance against the dye rhodamine B (RhB) in an aqueous medium. Thus, the kinetics constant for photolysis (absence of catalysts) and for the sample β-AgMo and the sample with 7.5% of GO (GO@β-AgMo_7.5) are 0.38 × 10^–3, 12 × 10^–3, and 23.72 × 10^–3 min^–1, respectively. Therefore, it is 62.5 times more efficient in the degradation of the RhB dye, which confirms the promising photocatalytic properties of the obtained composite.","PeriodicalId":29796,"journal":{"name":"ACS Physical Chemistry Au","volume":"12 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142227335","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}