化学•材料最新文献

{"title":"Diverging and Converging Propagation of the Polymerization Front of Cyclooctadiene for Tunable Front Velocity and Patterning.","authors":"Lily J Shan, Yuqun Feng, Yuan Gao","doi":"10.1021/acs.jpcb.5c01387","DOIUrl":"10.1021/acs.jpcb.5c01387","url":null,"abstract":"<p><p>Frontal polymerization (FP) with thermochemical instabilities provides a morphogenic manufacturing method for polymeric parts by autonomously forming patterned domains with different phases, leading to mechanical properties surpassing the homogeneous counterpart. The mechanical properties largely depend on the characteristics of the patterns. Understanding and controlling the pattern features are of vital importance to FP-based manufacturing processes. In the present study, we demonstrate that the geometry and propagating route of FP in cyclooctadiene have significant impacts on the front velocity and the pattern formed by the instability. By varying the diverging angle of the propagating route, the front velocity and the wavelength of the pattern can be typically adjusted by 25% and 50%, respectively. The tuning range on the wavelength of patterns is almost twice that with controlling merely the thermal condition. The tuning effects on the front velocity and pattern features are further validated with a parametric study. The mechanism of energy balance between the reaction and diffusion and the geometry-dependent cure kinetics are elucidated with detailed finite-element analyses. The current results and findings provide a fundamental understanding of unstable FP in various geometries and can theoretically guide the development of FP-based morphogenic manufacturing methods with adjustable material properties.</p>","PeriodicalId":60,"journal":{"name":"The Journal of Physical Chemistry B","volume":" ","pages":"5621-5629"},"PeriodicalIF":2.8,"publicationDate":"2025-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144109133","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 the Epidermal Growth Factor Receptor under Piconewton Mechanical Compressive Force Manipulations.","authors":"Dedunu S Senarathne, Lalita Shahu, H Peter Lu","doi":"10.1021/acs.jpcb.5c00800","DOIUrl":"10.1021/acs.jpcb.5c00800","url":null,"abstract":"<p><p>Studying the relationship among protein structure, dynamics, and function under external compressive forces offers valuable insights. While extensive research has focused on manipulating protein dynamics and ligand-receptor interactions under pulling forces, the exploration of protein conformational changes under compressive forces has been limited. In this study, we investigate the response of unliganded epidermal growth factor receptor (EGFR) monomers, liganded EGF-EGFR monomers, and dimers when exposed to external compressive forces using a home-modified AFM setup with an ultrasoft AFM tip. We observed that both ligand-bound and unbound EGFR proteins can undergo spontaneous tertiary structural rupture under piconewton-level compressive forces, a previously hidden protein behavior that may play a significant role in protein cell signaling. The magnitudes of the threshold compressive forces obtained in our study lie in the range of tens and hundreds of piconewtons (pN), which is accessible within a live biological system. Moreover, we developed a kinetic model to exhibit that only a fraction of the uniaxial compressive force exerted by the AFM tip affects the internal tension that causes a pseudopulling force within the protein before it undergoes the tertiary structural rupture. This calculated fraction ranged from 0.45 to 0.65, depending on the protein type and the approach velocity of the AFM tip. Additionally, we employed molecular dynamics (MD) simulations, particularly Steered MD (SMD) simulations along with Umbrella Sampling (US), to investigate the dynamics of unliganded and liganded EGFR in the presence of external compressive forces. These MD simulation results offer valuable insights into the flexibilities and unfolding behaviors of both liganded and unliganded EGFR proteins when subjected to external compressive forces.</p>","PeriodicalId":60,"journal":{"name":"The Journal of Physical Chemistry B","volume":" ","pages":"5411-5422"},"PeriodicalIF":2.8,"publicationDate":"2025-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144148679","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":"NixW1–x Nanoparticles as Electrocatalysts for Hydrogen Evolution in Acidic Medium","authors":"Kanghoon Choi, Sasha Omanovic","doi":"10.1021/acs.jpcc.5c02508","DOIUrl":"https://doi.org/10.1021/acs.jpcc.5c02508","url":null,"abstract":"This study investigates the electrocatalytic performance of nanostructured Ni–W electrocatalysts for the hydrogen evolution reaction (HER) in an acidic medium (0.5 M H₂SO₄). Electrocatalysts were synthesized using a solution combustion synthesis method, followed by metal reduction under a 10 vol % H₂/Ar atmosphere. By systematically varying the Ni-to-W atomic ratio in Ni_<i>x</i>W_1–<i>x</i> electrocatalysts (<i>x</i> = 0.1, 0.3, 0.5, 0.7, and 0.9), we identified the optimal composition for maximum HER activity. Comprehensive structural and electrochemical analyses, including X-ray diffraction, X-ray photoelectron spectroscopy, ultraviolet photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy, linear sweep voltammetry, and electrochemical impedance spectroscopy, were conducted to investigate phase composition, surface chemistry, work function (Φ), morphology, and HER catalytic activity. Among the compositions evaluated, Ni_0.7W_0.3 demonstrated superior HER performance, characterized by a Tafel slope of 100 ± 2 mV dec^–1, an exchange current density (<i>j</i>₀) of 677 ± 106 μA cm^–2, and an overpotential (η₁₀) of −143 ± 4 mV at a cathodic current density of −10 mA cm^–2. When compared to the previously reported Ni–W electrocatalysts for acidic HER, Ni_0.7W_0.3 stands out as one of the most effective electrocatalysts. This remarkable performance results from an optimized phase composition, enabling synergistic interactions among the Ni–W alloy phase, metallic tungsten, and oxygen-deficient tungsten oxide species. These structural features create an enhanced electronic environment, facilitating charge transport and promoting efficient water dissociation kinetics. Moreover, the high work function of Ni_0.7W_0.3 contributes to improved electron transfer kinetics, effectively lowering the energy barriers of the HER process. Its well-defined nanostructure, featuring multiple active edges and facets, further increases the density of accessible active sites, enhancing catalytic activity. Collectively, these findings highlight the potential of Ni–W electrocatalysts as cost-effective and highly efficient alternatives to noble metal-based electrocatalysts for acidic water electrolysis.","PeriodicalId":61,"journal":{"name":"The Journal of Physical Chemistry C","volume":"18 1","pages":""},"PeriodicalIF":4.126,"publicationDate":"2025-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144228887","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":"Visible-Light Photoredox-Catalyzed Carboxylation of Benzylic C(sp3)–O Bonds in Ethers with CO2","authors":"Jing-Wei Yang, Chuan-Kun Ran, Wen-Jing Zhu, Yi Jiang, Si-Shun Yan, Jian-Heng Ye, Da-Gang Yu","doi":"10.1021/acs.joc.5c01091","DOIUrl":"https://doi.org/10.1021/acs.joc.5c01091","url":null,"abstract":"Although significant progress has been made in achieving site-selective C–O bond functionalization in specific substrates, the selective cleavage and functionalization of C(sp³)–O bonds in ethers remain a fundamental challenge in synthetic chemistry. Herein, we present an efficient carboxylation method via the photoredox-catalyzed cleavage of benzylic C(sp³)–O bonds in ethers with carbon dioxide (CO₂). Diverse primary, secondary, and tertiary benzyl ethers undergo selective carboxylation with CO₂ to generate valuable aryl acetic acids, including several drug molecules. This photocatalyzed carboxylation reaction is operationally simple to implement and versatile for various benzylic ethers, exhibiting favorable compatibility with diverse functional groups. Mechanistic studies indicate that the single electron transfer (SET) reduction of ethers might be the key to generating a highly reactive radical anion intermediate, which could undergo C–O bond cleavage and another SET reduction process to generate carbanions for reaction with CO₂.","PeriodicalId":57,"journal":{"name":"Journal of Organic Chemistry","volume":"16 1","pages":""},"PeriodicalIF":4.354,"publicationDate":"2025-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144219580","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":"Retrieval of Genuine Ultraviolet Liquid-Microjet Photoelectron Spectra.","authors":"Edoardo Simonetti, Helen H Fielding","doi":"10.1021/acs.jpca.5c02024","DOIUrl":"https://doi.org/10.1021/acs.jpca.5c02024","url":null,"abstract":"<p><p>Ultraviolet liquid-microjet photoelectron spectroscopy is a powerful technique for the determination of electron binding energies of molecules in aqueous solution and for exploring their photochemical dynamics. However, our poor understanding of inelastic scattering of low energy electrons (<10 eV) in water has hindered the determination of accurate vertical ionization energies; although several algorithms have been implemented to retrieve genuine binding energies from experimental spectra, a consensus on the parameters employed is yet to be reached. Here, we investigate the effect of these parameters on the retrieval of true photoelectron spectra of water, phenol, and phenolate. We show that the scattering cross sections, obtained by extrapolating the cross sections in amorphous ice to zero electron kinetic energy, describe the distortion observed in our spectra accurately and that the description of the transmission of electrons at the liquid-vacuum interface is crucial to infer a value for the electron affinity of water at the surface, and we emphasize the importance of considering concentration depth profiles when retrieving true photoelectron spectra of surface-active solutes. Our work highlights the potential for accurate ultraviolet photoelectron spectroscopy of aqueous solutions of organic molecules.</p>","PeriodicalId":59,"journal":{"name":"The Journal of Physical Chemistry A","volume":" ","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144223742","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":"Proximity-Induced Fluorescence Quenching in Rhodamine Systems <i>In Vacuo</i>: Effect of Charges and Aromatic Moieties.","authors":"Thomas Toft Lindkvist, Lukas Raphael Benzenberg, Steen Brøndsted Nielsen, Renato Zenobi","doi":"10.1021/acs.jpca.5c03150","DOIUrl":"10.1021/acs.jpca.5c03150","url":null,"abstract":"<p><p>FRET is a valuable technique for exploring conformations of macromolecules in solution and in the gas phase. Donor fluorescence quenching is often identified from shortened excited-state lifetimes. However, when dyes are incorporated into proteins, the local microenvironment can affect the photophysics and energy transfer. To examine the effect of nearby charges and aromatic moieties on lifetimes, we investigated different cationic rhodamine-575 model systems <i>in vacuo</i>. In homodimers, the internal Coulomb repulsion induces a distance-dependent increase in lifetime, ranging from 5.90 ns (single dye) to 6.78 ns (shortest interdye linker), which we attribute to reduced oscillator strengths as corroborated by TD-DFT calculations. Our findings highlight that excited-state lifetimes are not necessarily directly correlated with fluorescence quantum yields, contrasting typical intuition. We discuss different quenching mechanisms and compare with results obtained in solution, as the opposite effect is observed in methanol, where excited-state lifetimes decrease upon bringing the dyes closer together. In the case of homotrimers in the gas phase, lifetimes systematically decrease with the number of nonprotonated (neutral) dyes. This suggests enhanced nonradiative decay rates driven by strong interactions between dyes and nearby aromatic moieties.</p>","PeriodicalId":59,"journal":{"name":"The Journal of Physical Chemistry A","volume":" ","pages":"4936-4943"},"PeriodicalIF":2.7,"publicationDate":"2025-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144109132","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":"Computing the pH-Dependent Thermodynamics of the Allostery between Dimerization and Palmitate Binding in β-Lactoglobulin.","authors":"Lucie da Rocha, Sara R R Campos, António M Baptista","doi":"10.1021/acs.jpcb.5c01119","DOIUrl":"10.1021/acs.jpcb.5c01119","url":null,"abstract":"<p><p>The study of pH-dependent allosteric processes presents a significant challenge, both experimentally and computationally. In this work, we apply the constant-pH molecular dynamics method to explore an interesting case of allostery involving protein-ligand binding and dimerization. As a model system, we use β-lactoglobulin (BLG), a small protein from bovine milk known to dimerize and bind palmitic acid in a hydrophobic pocket─both processes sensitive to pH. This study focuses on the holo form of BLG, and, when combined with our previous study of the apo form (da Rocha et al. <i>J. Chem. Theory Comput.</i> <b>2022</b> 18, 1982), completes the thermodynamic cycle of the allosteric process. The corresponding pH-dependent free energy profiles are obtained through the use of a thermodynamic linkage relation, avoiding the need of performing heavy computational calculations. Dimerization is found to be more favorable near the isoionic point, as observed in the apo form. Palmitate binding is found to be more favorable around pH 6-7, a biologically relevant pH range at which the gate covering the binding site is known to open. A pH-dependent measure of allosteric coupling is computed, showing that ligand binding and dimerization exhibit an antagonist relationship within the studied pH range of 3-8, with binding destabilizing dimerization and vice versa.</p>","PeriodicalId":60,"journal":{"name":"The Journal of Physical Chemistry B","volume":" ","pages":"5423-5437"},"PeriodicalIF":2.8,"publicationDate":"2025-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144126229","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":"Lysozyme in Mixtures of Hydrogen Bond Acceptor Solvents with Water: Enthalpies and Entropies of Preferential Solvation.","authors":"Vladimir A Sirotkin","doi":"10.1021/acs.jpcb.5c00304","DOIUrl":"10.1021/acs.jpcb.5c00304","url":null,"abstract":"<p><p>The main focus of this work is to clarify how enzyme macromolecules become solvated in water-organic mixtures and to estimate the enthalpies and entropies of this solvation process. Isothermal calorimetry and water/organic solvent adsorption measurements were used to investigate the preferential solvation of hen egg white lysozyme in hydrogen bond acceptor solvents at 298.15 K. Dimethyl sulfoxide, N,N-dimethylformamide, acetonitrile, 1,4-dioxane, and acetone were used as model organic cosolvents. Preferential solvation was described by analyzing the excess thermodynamic functions of the mixing. The novelty of this approach is that the enthalpies and entropies of protein, water, and organic solvents can be simultaneously investigated across the entire range of water content. There are three composition regimes in water-organic mixtures. Stabilization of the protein as a result of the preferential hydration of lysozyme was detected in the water-rich region. Protein stabilization is driven by the positive change in entropy. The residual enzyme activity values are close to 100%, compared with those for pure water. In the intermediate region, lysozyme has a higher affinity for organic solvent molecules than for water. The cosolvent-induced inactivation of lysozyme was detected at intermediate water content, and residual enzyme activity is close to zero. At the lowest water content, the cosolvent molecules are preferentially excluded from the protein surface, resulting in preferential hydration and nonzero residual enzyme activity. In the water-poor region, protein stabilization is driven by the exothermic enthalpy change. The present study clearly demonstrates that the preferential solvation thermodynamic quantities strongly depend on the acceptance strength of the cosolvent hydrogen bond.</p>","PeriodicalId":60,"journal":{"name":"The Journal of Physical Chemistry B","volume":" ","pages":"5386-5399"},"PeriodicalIF":2.8,"publicationDate":"2025-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144118349","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":"Examining the Role of Internal Electric Fields in Reducing Reaction Barriers in Cycloaddition Reactions of Oxygen-Bridged Al/P- and Si/P-Based Frustrated Lewis Pairs with Heterocumulenes.","authors":"Zheng-Feng Zhang, Ming-Der Su","doi":"10.1002/asia.202500431","DOIUrl":"https://doi.org/10.1002/asia.202500431","url":null,"abstract":"<p><p>In this investigation, computational methods were employed to study the transition-metal-free trapping reactions of small organic molecules using two distinct intramolecular frustrated Lewis pairs (FLPs) via cycloaddition mechanisms. The reactivity of oxygen-bridged geminal FLP-type molecules Al/P-Rea (1) and Si/P-Rea (2) with CS₂, PhN═C═S, SO₂, and PhN═S═O was evaluated. Experimental results reported by Mitzel and coworkers indicate that FLPs 1 and 2 alone exhibit limited ability to activate these four small molecules, being hindered by endergonic barriers, reaction thresholds, or potential structural degradation. Evidence from activation strain model (ASM) analysis suggests that the interaction of a larger FLP-type molecule with a chemical bond in a smaller organic molecule, or its binding to a single bond within a heterocumulene, induces enhanced motion within the smaller molecule (or heterocumulene). This increased motion leads to a significant rise in structural strain energy, which substantially affects the activation energy required for bonding. Alternatively, our ASM findings emphasize that when an FLP-type molecule binds simultaneously to both ends of a similar-sized organic molecule, the activation barrier is primarily governed by the strain energies of both reactants. Notably, this study further suggests that introducing cations (e.g., Li⁺) or anions (e.g., Cl⁻) into the reaction system of otherwise unreactive or weakly reactive FLP-type molecules induces an internal electric field that dramatically reduces the activation energy and enhances the exergonicity of the process, thereby facilitating the overall reaction. We hope that this study provides experimental synthetic chemists with novel insights and valuable guidance for future synthetic efforts.</p>","PeriodicalId":145,"journal":{"name":"Chemistry - An Asian Journal","volume":" ","pages":"e00431"},"PeriodicalIF":3.5,"publicationDate":"2025-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144223826","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":"New Exciplex-forming Cohost Systems Harnessing Acceptors With Phenanthrene and Phenanthroline Core for Near-Infrared OLEDs.","authors":"Guan-Cheng Liu, Tzu-Hao Huang, Yi-Yun Chen, Yu-Cheng Kung, Yuan-Chih Lo, Wen-Yi Hung, Ken-Tsung Wong","doi":"10.1002/asia.202500357","DOIUrl":"https://doi.org/10.1002/asia.202500357","url":null,"abstract":"<p><p>Two new acceptors, C-BPhCN and N-BPhCN, with 2,3-dicyanopyrazinophenanthrene and pyrazino[2,3-f][1,10]phenanthroline-2,3-dicarbonitrile core and ortho-linked biphenyl peripherals were synthesized and characterized. The exciplex formation of C-BPhCN and N-BPhCN as acceptor (A) and SBFC-G1 as donor (D) was examined. Through optimization, the device using a D:A (2:1) blend in emitting layer (EML) exhibited maximum external quantum efficiency (EQE_max) of 8.26% and 5.25% with electroluminescence peak (EL λ_max) centered at 581 and 595 nm, respectively. A new D-A-D configured near-infrared (NIR) fluorescent emitter DMACBBT was introduced as a dopant in the exciplex-forming cohost system. By tuning the thickness of the electron transporting layer (ETL), the EQE_max of the device employing SBFC-G1:C-BPhCN (2:1): 9 wt % DMACBBT as the EML reached 1.03% with EL λ_max at 808 nm. The counterpart device utilizing SBFC-G1:N-BPhCN (2:1): 9 wt % DMACBBT as the EML exhibited an EQE_max of 1.01% and EL λ_max at 817 nm. The stability of the NIR OLED device was measured, yielding lifetimes (T₆₀) of 182 and 126 h for SBFC-G1:C-BPhCN and SBFC-G1:N-BPhCN cohost-based devices, respectively. This work highlights the high efficiency of NIR OLEDs that can be practically realized by using the exciplex cohost systems with a tailor-made NIR fluorescent emitter.</p>","PeriodicalId":145,"journal":{"name":"Chemistry - An Asian Journal","volume":" ","pages":"e00357"},"PeriodicalIF":3.5,"publicationDate":"2025-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144223828","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}