化学•材料最新文献

{"title":"A Modular Approach to Tuning Emissive <i>N</i>-Quinolyl Through-Space Charge Transfer States Using sp³-Scaffolds.","authors":"Joseph O Watson, Ruth M Pollard, Mark T Sims, Marc K Etherington, Jonathan P Knowles","doi":"10.1021/acs.jpcb.4c05220","DOIUrl":"10.1021/acs.jpcb.4c05220","url":null,"abstract":"<p><p>We have shown that palladium-catalyzed cascade processes provide modular access to rigid quinoline-containing tetracyclic amines. This modular approach enables fine-tuning of the through-space charge transfer (TSCT) state formation between the lone pair localized on the nitrogen atom in the cage moiety and the quinoline moiety by variation of both the intramolecular <i>N</i>-aryl distance and quinoline substitution. Decreasing this <i>N</i>-aryl distance enhances the formation of the TSCT species, giving control over the emission color and photoluminescence quantum yield. Methoxylation of the quinoline unit decreases the propensity of TSCT formation. The development of this structure-activity relationship provides great insight for TSCT formation with an impact on further understanding dimeric, excimeric, and exciplex species. This understanding is crucial for the work underpinning their use in biosensor applications, and the conclusions are of relevance to the broader field of photoluminescence.</p>","PeriodicalId":60,"journal":{"name":"The Journal of Physical Chemistry B","volume":null,"pages":null},"PeriodicalIF":2.8,"publicationDate":"2024-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142575451","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Gas Phase Reactions of Pristine and Single-Atom-Doped Copper and Silver Clusters: Probing Size-Dependent Stability and Novel Superatoms.","authors":"Qiuying Du, Zhixun Luo, Xiaopeng Xing, Jijun Zhao","doi":"10.1021/acs.jpclett.4c02582","DOIUrl":"10.1021/acs.jpclett.4c02582","url":null,"abstract":"<p><p>Gas phase reactions have been a subject of research interest, enabling reliable strategies to explore the stability and reactivity of metal clusters as well as to probe novel superatoms that form the building blocks to assemble new materials with tailored properties. Coinage metal clusters have attracted great research attention due to their simple electronic shell structures and rich photochemical and catalytic properties at relatively low cost. This perspective focuses on the recent progress made in studying the gas phase reactions of undamaged and single-atom-doped Cu_<i>n</i>^±,0 and Ag_<i>n</i>^±,0 clusters with O₂, CO, and NO molecules. It covers various aspects, such as reaction mechanisms, relationships between structure and activity, control of reactivity by changing cluster size and composition, and the identification of novel superatoms (Cu₁₈^-, Ag₁₃^-, Ag₁₇^-, and Ag₁₅O⁺). Lastly, we provide a detailed account of the obstacles and prospective avenues for future research in order to establish a connection between these findings and nanocluster systems that have practical applications.</p>","PeriodicalId":62,"journal":{"name":"The Journal of Physical Chemistry Letters","volume":null,"pages":null},"PeriodicalIF":4.8,"publicationDate":"2024-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142581021","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Neural Thermodynamic Integration: Free Energies from Energy-Based Diffusion Models.","authors":"Bálint Máté, François Fleuret, Tristan Bereau","doi":"10.1021/acs.jpclett.4c01958","DOIUrl":"10.1021/acs.jpclett.4c01958","url":null,"abstract":"<p><p>Thermodynamic integration (TI) offers a rigorous method for estimating free-energy differences by integrating over a sequence of interpolating conformational ensembles. However, TI calculations are computationally expensive and typically limited to coupling a small number of degrees of freedom due to the need to sample numerous intermediate ensembles with sufficient conformational-space overlap. In this work, we propose to perform TI along an alchemical pathway represented by a trainable neural network, which we term Neural TI. Critically, we parametrize a time-dependent Hamiltonian interpolating between the interacting and noninteracting systems and optimize its gradient using a score matching objective. The ability of the resulting energy-based diffusion model to sample all intermediate ensembles allows us to perform TI from a single reference calculation. We apply our method to Lennard-Jones fluids, where we report accurate calculations of the excess chemical potential, demonstrating that Neural TI reproduces the underlying changes in free energy without the need for simulations at interpolating Hamiltonians.</p>","PeriodicalId":62,"journal":{"name":"The Journal of Physical Chemistry Letters","volume":null,"pages":null},"PeriodicalIF":4.8,"publicationDate":"2024-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142581024","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Probing Aromaticity with Supersonic Jet Spectroscopy: A Case Study on Furan, Thiophene, and Selenophene.","authors":"Akshay Kumar Sahu, Anant Ram Satpathi, Saiprakash Rout, Pranay Mohanty, Laxmipriya Dash, Himansu S Biswal","doi":"10.1021/acs.jpclett.4c02791","DOIUrl":"https://doi.org/10.1021/acs.jpclett.4c02791","url":null,"abstract":"<p><p>Aromaticity is a century-old concept that is even introduced in high school textbooks. However, the determination of the order of aromaticity of molecules as simple as furan, thiophene, and selenophene is still challenging. This work describes how different theoretical and experimental methods posit different aromaticity orders. To benchmark the theoretical results and arrive at a conclusion, mass-selective electronic and vibrational spectroscopy of these five-membered heterocycles under isolated supersonic-jet-cooled conditions was necessary. Since the aromaticity order can be unveiled from the magnitude of the electron density in the ring, we used hydrogen bonding as a probe. The experimental results revealed that selenophene forms the strongest π-hydrogen bond, suggesting that selenophene is the most aromatic, followed by thiophene and furan. It is concluded that gauge-including magnetically induced currents (GIMIC) and relative ¹H and ¹³C NMR chemical shifts are better parameters to determine the aromaticity order in a similar class of molecules.</p>","PeriodicalId":62,"journal":{"name":"The Journal of Physical Chemistry Letters","volume":null,"pages":null},"PeriodicalIF":4.8,"publicationDate":"2024-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142602156","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Development of Neural Network Potentials for Studying Chemical Behaviors of La³⁺/Nd³⁺ Ions in Molten LiCl-KCl-CsCl in Combination with Raman Spectroscopy.","authors":"Yi-Zhi Han, Yi-Chuan Liu, Jian-Hui Lan, Ya-Lan Liu, Cong-Zhi Wang, Qun-Yan Wu, Xiang-Dong Ding, Xue Liu, Anastasia O Khudorozhkova, Michael V Laptev, Yury P Zaikov, Wei-Qun Shi","doi":"10.1021/acs.jpcb.4c04750","DOIUrl":"10.1021/acs.jpcb.4c04750","url":null,"abstract":"<p><p>The chemistry of molten salts has attracted great research interest owing to their wide applications in diverse fields. In the pyrochemical reprocessing of spent nuclear fuel or molten salt nuclear reactors, lanthanide elements as the principal fission products bring about changes in the composition and properties of molten salts. Herein, we report a comprehensive study on the coordination chemistry of the representative trivalent lanthanide ions (La³⁺/Nd³⁺) in LiCl-KCl-CsCl using a multiscale strategy combining Raman spectroscopy, deep learning, and large-scale molecular dynamics (MD) simulations. The neural network potential (NNP)-based MD and Raman spectroscopy studies revealed that La³⁺/Nd³⁺ ions prefer to form persistent octahedron complexes with the six-coordinated species as the dominant species at high temperatures. Compared to LaCl₆^3-, NdCl₆^3- shows higher stability with obviously longer lifetimes in LiCl-KCl-CsCl, as confirmed by the observed stronger interaction of Nd³⁺-Cl^- pairs. The total and partial structure factors further indicated the formation of a more stable network structure in LiCl-KCl-CsCl containing NdCl₃. Besides, the temperature exerts a larger influence on the local structures of the La³⁺ species compared to the Nd³⁺ analogues. According to the potential mean force calculations, the bond dissociation energies follow the order Ln-Cl > Li-Cl > K-Cl > Cs-Cl in LiCl-KCl-CsCl-LnCl₃. The NNP-based large-scale MD simulations have been verified to be an efficient and powerful way in molten salt chemistry research.</p>","PeriodicalId":60,"journal":{"name":"The Journal of Physical Chemistry B","volume":null,"pages":null},"PeriodicalIF":2.8,"publicationDate":"2024-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142556665","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Medium-Range Structural Order as the Driver of Activated Dynamics and Complexity Reduction in Glass-Forming Liquids.","authors":"Baicheng Mei, Kenneth S Schweizer","doi":"10.1021/acs.jpcb.4c05488","DOIUrl":"10.1021/acs.jpcb.4c05488","url":null,"abstract":"<p><p>We analyze in depth the Elastically Collective Nonlinear Langevin Equation theory of activated dynamics in metastable liquids to establish that the predicted inter-relationships between the alpha relaxation time, local cage and collective elastic barriers, dynamic localization length, and shear modulus are causally related within the theory to the medium range order (MRO) static correlation length. The latter grows exponentially with density for metastable hard sphere fluids and as a nonuniversal inverse power law with temperature for supercooled liquids under isobaric conditions. The physical origin of predicted connections between the alpha time and other metrics of cage order and the thermodynamic inverse dimensionless compressibility is fully established. It is discovered that although kinetic constraints from the real space first coordination shell are important for the alpha time, they are of secondary importance compared to the consequences of the more universal MRO correlations in both the modestly and deeply metastable regimes. This understanding sheds new light on the theoretical basis for, and prior successes of, the predictive mapping of chemically complex thermal liquids to effective hard sphere fluids based on matching their dimensionless compressibilities, a scheme we call \"complexity reduction\". In essence, the latter is equivalent to the physical requirement that the thermal liquid MRO correlation equals that of its effective hard sphere analog. The mapping alone is shown to provide a remarkable level of quantitative predictive power for the glass transition temperature <i>T</i>_g of 21 molecular and polymer liquids. Predictions for the chemically specific absolute magnitude and growth with cooling of the MRO correlation length are obtained and lie in the window of 2-6 nm at <i>T</i>_g. Dynamic heterogeneity, elastic facilitation, and beyond pair structure issues are briefly discussed. Future opportunities to theoretically analyze the equilibrated deep glass regime are outlined.</p>","PeriodicalId":60,"journal":{"name":"The Journal of Physical Chemistry B","volume":null,"pages":null},"PeriodicalIF":2.8,"publicationDate":"2024-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142556669","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Modulation of the Chirality and Dynamics of Self-Assembled Nanocellulose-Chiral C-Dot Film for Chiral Sensing Applications.","authors":"Sapna Waghmare, Umarfaruk S Sayyad, Arunavo Chatterjee, Somen Mondal","doi":"10.1021/acs.jpclett.4c02564","DOIUrl":"10.1021/acs.jpclett.4c02564","url":null,"abstract":"<p><p>The detection and sensing of chirality using chiral biomaterials are growing areas of research in advanced bioelectronics. As a result, chiral-controlled biomaterials are crucial for advancing current technologies in chiral sensing applications within biosystems. A chiral carbon dot (C-dot) modulated self-assembled emissive cellulose nanocrystal (CNC) film is developed where the chirality of the CNC film can be tempered between left-handed and right-handed chirality after being doped with chiral L/D-C-dots in CNCs (C-dot-CNC film), transferring the chirality from C-dots to CNCs. The interaction between C-dots, CNCs, and carrier dynamics is investigated using a variety of steady-state and time-resolved PL spectroscopy techniques. The chiral C-dot enhanced the protonic conductivity across the CNC via the formation of hydrogen bonds with its surface functional groups and water molecules. Further, the chiral CNC-C-dots photoelectrodes demonstrate an excellent ability to distinguish between left-handed and right-handed small molecules. These findings on the underlying mechanism of spin selectivity between chiral CNC-C-dot and chiral ligand hold promise for the development of efficient chiral-sensing electronic devices.</p>","PeriodicalId":62,"journal":{"name":"The Journal of Physical Chemistry Letters","volume":null,"pages":null},"PeriodicalIF":4.8,"publicationDate":"2024-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142566367","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Catalytic Effect of Potassium Xanthates and Related Compounds on Disulfide Bond Enrichment of Polyalkylene Sulfides Synthesized in the Course of Episulfide Polymerization.","authors":"Mikhail Rumyantsev, Ivan Yu Kalagaev, Sergey Rumyantsev","doi":"10.1021/acs.jpcb.4c05474","DOIUrl":"10.1021/acs.jpcb.4c05474","url":null,"abstract":"<p><p>The original method for the preparation of high-molecular-weight polyalkylene sulfides was reported. Assuming anomalous peculiarities of the reaction (high polymerization rates, high degrees of polymerization, and huge discrepancy between the expected <i>M</i>_n values and the experimentally obtained values), the priority task was set to study the mechanism underlying the observed new type of polymerization. Thus, it was demonstrated that xanthate and related molecules could act as pure catalysts, facilitating both the chain-growth polymerization (ring-opening of episulfides) realized via an anionic route and the direct attack of the sulfur atom of one episulfide molecule on the methylene carbon atom of the second (neighbor) episulfide molecule, accompanied by the subsequent formation of a stable thiiranium-based zwitterionic adduct. The role of xanthate and related compounds as catalysts and stabilizing particles was further supplemented by modeling the attack of thiolate on the sulfur atom of a thiiranium-based adduct. The xanthate molecule acting as a catalyst was found to be involved in all stages of the process discussed by sharing the potassium atom with the sulfur atoms of active components of the system (the initial episulfide molecule, thiolate, and the zwitterionic intermediate). The subsequent analysis revealed the exceptional transparency of the materials obtained, which was found to exceed 99%. The pronounced self-healing ability was also found to be a distinctive feature of the synthesized high-molecular-weight polyalkylene sulfides enriched with disulfide bonds.</p>","PeriodicalId":60,"journal":{"name":"The Journal of Physical Chemistry B","volume":null,"pages":null},"PeriodicalIF":2.8,"publicationDate":"2024-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142566429","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Optical Sensitivity of Multipole Resonant Gold Nanorods in Solution and Film","authors":"Kyoungweon Park, Richard Sottie, Eva Yazmin Santiago, Oscar Avalos-Ovando, Alexander Govorov, Richard A. Vaia","doi":"10.1021/acs.jpcc.4c06417","DOIUrl":"https://doi.org/10.1021/acs.jpcc.4c06417","url":null,"abstract":"Ensembles of large aspect ratio gold rods (AuNRs) are of technological interest due to their extreme optical cross-section at visible and near-infrared wavelengths (<i>C</i> ∼ 10⁴–10⁵ nm²), ultrafast plasmonic and excitonic character (τ ∼ fs–ps), and responsivity to external fields affording ensemble alignment (ns−μs). With increasing aspect ratio and nanorod volume, plasmonic modes beyond dipolar emerge due to phase retardation. Such multipole resonances exhibit larger quality factors due to greater electromagnetic field localization, which is advantageous for optical signal routing, photon manipulation, or multistep processes such as second-harmonic generation, bioimaging, and photocatalysis. However, polydispersity of most as-synthesized AuNRs obscures these physicochemical behaviors across an ensemble, and thus at the macroscale. Herein, we present synthesis procedures for single-crystal AuNRs that simultaneously satisfy production scalability and ultralow dispersity with geometric tunability (aspect ratio:5 to 10; structural dispersity &lt;0.1). Quadrupole and octupole resonances are observed in solutions and nanocomposite films with &gt;10 nM AuNRs. The relationship between multipole resonance, aspect ratio, dielectric environment, temperature, and polarization agrees with theoretical predictions, confirming the foundation for the use of these effects in future technologies.","PeriodicalId":61,"journal":{"name":"The Journal of Physical Chemistry C","volume":null,"pages":null},"PeriodicalIF":4.126,"publicationDate":"2024-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142610046","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}

{"title":"A Tale of Two Cities in Fluorescent Sensing of Carbon Monoxide: Probes That Detect CO and Those That Detect Only Chemically Reactive CO Donors (CORMs), but Not CO","authors":"Dongning Liu, Xiaoxiao Yang, Binghe Wang","doi":"10.1021/acs.joc.4c02301","DOIUrl":"https://doi.org/10.1021/acs.joc.4c02301","url":null,"abstract":"Carbon monoxide (CO) is endogenously produced with a range of pharmacological activities. Sensitive and selective detection of CO is critical to studying its biology. Since the first report of a CO fluorescent probe in 2012, more than 100 papers on this topic have appeared. Noteworthy in such work is the widespread use of two commercially available ruthenium–carbonyl complexes (CORM-2 and CORM-3) as CO surrogates. Unfortunately, these two CORMs are chemically very reactive and preferentially release CO₂ but not CO, unless in the presence of a nucleophile. As a result, there are “two tales” of the reported CO probes: those that detect CO and those that detect only the CORM used but not CO. In addition, because of their lack of reliable CO production and fast degradation in an aqueous solution, there is the question of what “detecting CORM-2 or CORM-3” really means in the context of CO research. Additionally, for applying fluorescent CO probes in detecting low levels (often nanomolar) of CO <i>in vivo</i>, fast reaction kinetics is a prerequisite for meaningful results. In this Perspective, we discuss in detail these issues with the understanding of the evolutionary nature of scientific discoveries and the aim of preventing further confusion.","PeriodicalId":57,"journal":{"name":"The Journal of Organic Chemistry","volume":null,"pages":null},"PeriodicalIF":4.354,"publicationDate":"2024-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142610391","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}