ACS Publications最新文献_第6页

In Silico Formation of Polyphosphazene Networks Based on Phloroglucinol (Phg) and Hexachlorocyclotriphosphazene (HCCP): Structural and Mechanical Properties as a Function of the Phg:HCCP Ratio.

IF 2.7 2区化学

The Journal of Physical Chemistry A Pub Date : 2025-04-03 Epub Date: 2025-03-25 DOI: 10.1021/acs.jpca.5c00277

Sylvie Neyertz, Méryll Barraco, Nieck E Benes, David Brown

{"title":"In Silico Formation of Polyphosphazene Networks Based on Phloroglucinol (Phg) and Hexachlorocyclotriphosphazene (HCCP): Structural and Mechanical Properties as a Function of the Phg:HCCP Ratio.","authors":"Sylvie Neyertz, Méryll Barraco, Nieck E Benes, David Brown","doi":"10.1021/acs.jpca.5c00277","DOIUrl":"10.1021/acs.jpca.5c00277","url":null,"abstract":"Twenty-four molecular models for polyphosphazene networks were created via an in silico polymerization of phloroglucinol Phg (C6H6O3) and hexachlorocyclotriphosphazene HCCP (N3P3Cl6) mixtures at different Phg:HCCP ratios. A series of monomer mixtures at Phg-to-HCCP stoichiometric ratios ranging from 1:1 to 8:1 were created using molecular dynamics (MD) simulations. Alternating phases of reactions followed by relaxation steps led to the progressive formation of percolating polyphosphazene networks. The actual ratios of Phg to HCCP rings incorporated in the network polymers remained close to those in the mixtures for initial ratios up to 2:1. Above 2:1, there was a gradual divergence toward lower values in the networks as the limits to the number of possible bonds for each monomer started to take effect. The details of the structures were found to be very complex in terms of the probability distributions of links per Phg or HCCP ring. The highest degrees of connectivity and ring packing densities were found in the networks formed from the initial mixtures having Phg-to-HCCP ratios of around 2:1. Mechanical tests were carried out in order to ascertain the resistance of the model polyphosphazene networks to compression/decompression. There again, the networks obtained from the 2:1 initial mixture were found to have the highest Young's modulus and to display the most elasticity as they recovered their initial shape once the compression was removed. The influence of trapped excess monomers in the percolating networks was only noticeable at the highest mixture ratios. The most resistant Phg-HCCP networks are thus obtained from Phg-to-HCCP mixture ratios of around 2:1, with or without trapped excess monomers.","PeriodicalId":59,"journal":{"name":"The Journal of Physical Chemistry A","volume":" ","pages":"3148-3165"},"PeriodicalIF":2.7,"publicationDate":"2025-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143699110","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}

引用次数: 0

A Tribute to Alec M. Wodtke

IF 3.3 3区化学

The Journal of Physical Chemistry C Pub Date : 2025-04-03 DOI: 10.1021/acs.jpcc.5c0132110.1021/acs.jpcc.5c01321

Hua Guo*, Gerard Meijer* and Xueming Yang*,

引用次数: 0

VUV Photoionization Induced Proton Transfer and Formation of New Covalent Bonds in Pyridine-Methanol Complex.

IF 2.7 2区化学

The Journal of Physical Chemistry A Pub Date : 2025-04-03 Epub Date: 2025-03-20 DOI: 10.1021/acs.jpca.5c00286

Bingbing Wu, Yujian Li, Shenghui Xu, Jingyu Li, Ming Wei, Dandan Wang, Min Xie, Yongjun Hu

{"title":"VUV Photoionization Induced Proton Transfer and Formation of New Covalent Bonds in Pyridine-Methanol Complex.","authors":"Bingbing Wu, Yujian Li, Shenghui Xu, Jingyu Li, Ming Wei, Dandan Wang, Min Xie, Yongjun Hu","doi":"10.1021/acs.jpca.5c00286","DOIUrl":"10.1021/acs.jpca.5c00286","url":null,"abstract":"Ion-molecule reactions are a crucial form of reaction in space that can reveal the formation mechanisms and evolutionary processes of some complex interstellar molecules and even prebiotic molecules. In this study, infrared spectra of pyridine (Pyd) and methanol (CH3OH) or deuterated methanol (CH3OD) clusters were measured in the spectral range of 2400-3800 cm-1 using an infrared-vacuum ultraviolet (IR-VUV) scheme. The geometric conformer, infrared spectra of the possible products, and reaction paths were investigated utilizing quantum chemical calculations. By comparing the experimental and theoretically calculated spectra, we found that only a unique hydrogen-bonded structure exists within the Pyd-CH3OH complex, characterized by a linear hydrogen bond conformer between the two constituent molecules. On the other hand, interestingly, we observed a relatively weak NH vibrational peak at 3383 cm-1 in the infrared spectra of both cationic Pyd-CH3OH and Pyd-CH3OD, suggesting that proton transfer has occurred via at least two distinct pathways. These pathways likely involve a proton transfer reaction from either the OH group or the CH3 group of CH3OH to the nitrogen atom of Pyd, with the transfer from the OH group being the predominant route. Through the theoretical calculations, we also found that a new C-C bond can be formed between the two moieties after the proton transfer reactions.","PeriodicalId":59,"journal":{"name":"The Journal of Physical Chemistry A","volume":" ","pages":"3012-3019"},"PeriodicalIF":2.7,"publicationDate":"2025-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143668494","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}

引用次数: 0

Ultrasensitive Differential Scanning Calorimetric (US-DSC) Study of the Thermal-Induced Dynamic Transition Behaviors of PEO-PPO-PEO in Aqueous Solution.

IF 2.8 2区化学

The Journal of Physical Chemistry B Pub Date : 2025-04-03 Epub Date: 2025-03-20 DOI: 10.1021/acs.jpcb.4c08247

Lin Li, Kang Ni, Lvdan Liu, Yuxia Bai, Yanwei Ding

{"title":"Ultrasensitive Differential Scanning Calorimetric (US-DSC) Study of the Thermal-Induced Dynamic Transition Behaviors of PEO-PPO-PEO in Aqueous Solution.","authors":"Lin Li, Kang Ni, Lvdan Liu, Yuxia Bai, Yanwei Ding","doi":"10.1021/acs.jpcb.4c08247","DOIUrl":"10.1021/acs.jpcb.4c08247","url":null,"abstract":"Temperature-responsive macromolecules can provide insights into the mechanisms of the aggregation and precipitation processes of proteins. In this study, the PEO-PPO-PEO triblock copolymer, Pluronic P123, has been utilized as a protein model to investigate the thermally induced dynamic transition behavior by ultrasensitive differential scanning calorimetry (US-DSC). The results of US-DSC reveal hysteresis in the disaggregation process of P123 micelles. Combined with the particle size distribution, a stepwise disaggregation mechanism is proposed. The disaggregation of P123 micelles in the cooling process involved rod-to-sphere transition, fragmentation, and dissolution of micelles. Moreover, US-DSC results show that both the sphere-to-rod transition and micelle fragmentation are dependent on the scanning rate and reveal the relationship between the dynamic transition and thermodynamic properties of P123. These findings expand the understanding not only of aggregation and disaggregation of P123 in dilute aqueous systems but also of the thermal unfolding and aggregation of proteins.","PeriodicalId":60,"journal":{"name":"The Journal of Physical Chemistry B","volume":" ","pages":"3482-3491"},"PeriodicalIF":2.8,"publicationDate":"2025-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143661595","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}

引用次数: 0

Improved Metal-Semiconductor Interface in Monolayer (1L)-MoS₂ via Thermally-Driven Ag Filaments as Atomic Scale Edge Contacts Triggered by Selective Annealing Process Using Long Wavelength (1064 nm) Pulsed Laser.

IF 8.3 2区材料科学

ACS Applied Materials & Interfaces Pub Date : 2025-04-03 DOI: 10.1021/acsami.4c20612

Sumayah-Shakil Wani, Yao-Ren Kuo, K M M D K Kimbulapitiya, Ruei-Hong Cyu, Chieh-Ting Chen, Ming-Jin Liu, Huynh-Uyen-Phuong Nguyen, Bushra Rehman, Xin-Rui Liu, Feng-Chuan Chuang, Yen-Fu Lin, Chang-Hong Shen, Po-Wen Chiu, Yu-Lun Chueh

{"title":"Improved Metal-Semiconductor Interface in Monolayer (1L)-MoS2 via Thermally-Driven Ag Filaments as Atomic Scale Edge Contacts Triggered by Selective Annealing Process Using Long Wavelength (1064 nm) Pulsed Laser.","authors":"Sumayah-Shakil Wani, Yao-Ren Kuo, K M M D K Kimbulapitiya, Ruei-Hong Cyu, Chieh-Ting Chen, Ming-Jin Liu, Huynh-Uyen-Phuong Nguyen, Bushra Rehman, Xin-Rui Liu, Feng-Chuan Chuang, Yen-Fu Lin, Chang-Hong Shen, Po-Wen Chiu, Yu-Lun Chueh","doi":"10.1021/acsami.4c20612","DOIUrl":"https://doi.org/10.1021/acsami.4c20612","url":null,"abstract":"Here, we explore the effectiveness of a pulsed laser annealing (PLA) process to trigger atomic scale edge contacts by Ag filaments in reducing the contact resistance of a MoS2 field-effect transistor (FET). Employing a long wavelength (1064 nm) pulsed laser, we anneal monolayer (1L)-MoS2 FETs with various metal electrodes, including Ag/Au, Ni/Au, and Cr/Au. A remarkable enhancement in FET performance could be achieved after the PLA treatment. Specifically, Ag/Au-contacted 1L-MoS2 FETs after the PLA treatment exhibit a peak field-effect mobility increase from 60 to 135 cm2 V-1 s-1 and an on-current improvement from 40.5 to 96.1 μA at a Vd of 1 V, accompanied by a significant decrease in contact resistance to 0.29 kΩ μm. PLA-treated 1L-MoS2 FETs showed a high on/off ratio of 107. TEM analysis provided insight into the mechanism of reduced contact resistance, revealing the thermally driven diffusion of Ag atoms into the 1L-MoS2 as Ag filaments to lateral contact with the edge of the 1L-MoS2, namely atomic scale edge contacts, as a key contributing factor. Furthermore, our investigation extends to the larger scale CVD-grown 1L-MoS2 films, where the PLA treatment demonstrates notable improvements in mobility, on-current, and on-off ratio.","PeriodicalId":5,"journal":{"name":"ACS Applied Materials & Interfaces","volume":" ","pages":""},"PeriodicalIF":8.3,"publicationDate":"2025-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143770686","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Interaction of Arginine and Tryptophan-Rich Short Antimicrobial Peptides with Membrane Models: A Combined Fluorescence, Simulations, and Theoretical Approach.

IF 5.6 2区化学

Journal of Chemical Information and Modeling Pub Date : 2025-04-03 DOI: 10.1021/acs.jcim.5c00139

Bogdan Zorila, George Necula, Lorant Janosi, Ioan Turcu, Mihaela Bacalum, Mihai Radu

{"title":"Interaction of Arginine and Tryptophan-Rich Short Antimicrobial Peptides with Membrane Models: A Combined Fluorescence, Simulations, and Theoretical Approach.","authors":"Bogdan Zorila, George Necula, Lorant Janosi, Ioan Turcu, Mihaela Bacalum, Mihai Radu","doi":"10.1021/acs.jcim.5c00139","DOIUrl":"https://doi.org/10.1021/acs.jcim.5c00139","url":null,"abstract":"The augmented increase in bacterial antimicrobial resistance necessitates the discovery of alternative antimicrobial molecules such as short antimicrobial peptides (AMPs) with antimicrobial activity and low cytotoxicity. While many such peptides have been studied, their selective affinity for bacterial versus mammalian membranes remains unclear. Here, we propose a complementary approach using state-of-the-art fluorescence experiments, molecular dynamics simulations, and theoretical techniques. The main goal of this approach is to unravel the energetics and molecular interactions of AMPs with different membrane models at the lipid-water interface. We use short Trp- and Arg-rich AMPs, pure phosphatidylcholine (PC), and an 85:15 mixture of PC with phosphatidylglycerol (PG) lipids for the mammalian and bacterial model membranes, respectively. First, we found that the electrostatic interaction of PG headgroups with Arg enhances the peptide interaction with mixed bilayers by 25-30%, leading to increased hydrogen bonding and stronger membrane adhesion. Second, the obtained Gibbs free energies revealed significantly distinct partitioning of the AMP at the interface for the two bilayers, suggesting a qualitatively different insertion method of cationic AMPs into each of the two membrane models. These results highlight the potential of our approach to unravel the membrane selectivity of an AMP in the context of AMP-based rational design of antibiotics.","PeriodicalId":44,"journal":{"name":"Journal of Chemical Information and Modeling ","volume":" ","pages":""},"PeriodicalIF":5.6,"publicationDate":"2025-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143770729","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}

引用次数: 0

Exceptionally Strong Double-Layer Barriers Generated by Polyampholyte Salt.

IF 2.8 2区化学

The Journal of Physical Chemistry B Pub Date : 2025-04-03 DOI: 10.1021/acs.jpcb.5c00012

David Ribar, Clifford E Woodward, Jan Forsman

{"title":"Exceptionally Strong Double-Layer Barriers Generated by Polyampholyte Salt.","authors":"David Ribar, Clifford E Woodward, Jan Forsman","doi":"10.1021/acs.jpcb.5c00012","DOIUrl":"https://doi.org/10.1021/acs.jpcb.5c00012","url":null,"abstract":"Experiments using the surface force apparatus have found anomalously long-range interactions between charged surfaces in concentrated salt solutions. Ion clustering has been suggested as a possible origin of this behavior. In this work, we demonstrate that if such stable clusters indeed form, they are able to induce remarkably strong free energy barriers under conditions where a corresponding solution of simple salt provides negligible forces. Our cluster model is based on connected ions producing a polyampholyte salt containing a symmetric mixture of monovalent cationic and anionic polyampholytes. Ion distributions and surface interactions are evaluated utilizing statistical-mechanical (classical) polymer density functional theory, cDFT. In the Supporting Information, we briefly investigate a range of different polymer architectures (connectivities), but in the main part of the work, a polyampholyte ion is modeled as a linear chain with alternating charges, in which the ends carry an identical charge (hence, a monovalent net charge). These salts are able to generate repulsions, between similarly charged surfaces, of a remarkable strength, exceeding those from simple salts by orders of magnitude. The underlying mechanism for this is the formation of brush-like layers at the surfaces, i.e., the repulsion is strongly related to excluded volume effects, in a manner similar to the interaction between surfaces carrying grafted polymers. We believe our results are relevant not only to possible mechanisms underlying anomalously long-ranged underscreening in concentrated simple salt solutions but also for the potential use of synthesized polyampholyte salt as extremely efficient stabilizers of colloidal dispersions.","PeriodicalId":60,"journal":{"name":"The Journal of Physical Chemistry B","volume":" ","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143770752","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}

引用次数: 0

Looking Backward and Forward

IF 2.7 2区化学

The Journal of Physical Chemistry A Pub Date : 2025-04-03 DOI: 10.1021/acs.jpca.5c0132410.1021/acs.jpca.5c01324

Alec Wodtke*,

引用次数: 0

Plasticization Effects of PEG of Low Molar Fraction and Molar Mass on the Molecular Dynamics and Crystallization of PLA-b-PEG-b-PLA Triblock Copolymers Envisaged for Medical Applications.

IF 2.8 2区化学

The Journal of Physical Chemistry B Pub Date : 2025-04-03 Epub Date: 2025-03-19 DOI: 10.1021/acs.jpcb.5c00171

Nikolaos D Bikiaris, Panagiotis A Klonos, Evi Christodoulou, Panagiotis Barmpalexis, Apostolos Kyritsis

{"title":"Plasticization Effects of PEG of Low Molar Fraction and Molar Mass on the Molecular Dynamics and Crystallization of PLA-b-PEG-b-PLA Triblock Copolymers Envisaged for Medical Applications.","authors":"Nikolaos D Bikiaris, Panagiotis A Klonos, Evi Christodoulou, Panagiotis Barmpalexis, Apostolos Kyritsis","doi":"10.1021/acs.jpcb.5c00171","DOIUrl":"10.1021/acs.jpcb.5c00171","url":null,"abstract":"We prepared and studied a series of triblock copolymers based on poly(ethylene glycol) (PEG) and poly(lactic acid) (PLA). PLA blocks were in situ by ring-opening polymerization (ROP) of lactide (LA) onto the two sites of PEG. While in our recent work on similar copolymers with varying LA/PEG molar ratios and fixed PEG blocks [Bikiaris, N. D. Mater. Today Commun. 2024, 38, 107799], herein, we kept this ratio quite low, at 640/1, and employed different molecular weights, Mn, of the initial PEG at 1, 4, 6, and 8 kg/mol. The triblocks demonstrated high homogeneity, as manifested by the single thermal transition (glass transition, crystallization) with corresponding alternations in a systematic way with the Mn of PEG. With the increase of the latter Mn, accelerated segmental mobility and lowering of Tg by up to 15 K were recorded, accompanied by suppression in the chain fragility (cooperativity). Compared with linear PLAs of various Mns [Klonos, P. A. Polymer 2024, 305, 127177] and other PLA-based copolymers prepared by similar ROPs, with the overall Mn of our copolymers, PEG here sees to play the role of plasticizer on PLA, leading to increased free volume. Due to these effects, in general, the low crystalline fraction of PLA (∼3%) was significantly enhanced in the copolymers (20-26%), and the formed spherulites were mainly enlarged. Contrary to these, nucleation was barely affected; thus, the copolymers exhibited altered semicrystalline morphologies as compared to that in neat PLA. Both aspects of molecular dynamics, free volume and crystallization, were connected to the processability as well as the performance of these systems, considering the envisaged biomedical applications.","PeriodicalId":60,"journal":{"name":"The Journal of Physical Chemistry B","volume":" ","pages":"3514-3528"},"PeriodicalIF":2.8,"publicationDate":"2025-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143661581","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}

引用次数: 0

Isotope Effect on the Few-Femtosecond Relaxation Dynamics of the Ethylene Cation.

IF 2.7 2区化学

The Journal of Physical Chemistry A Pub Date : 2025-04-03 Epub Date: 2025-03-26 DOI: 10.1021/acs.jpca.5c01020

Matteo Lucchini, Manuel Cardosa-Gutierrez, Mario Murari, Fabio Frassetto, Luca Poletto, Mauro Nisoli, Francoise Remacle

{"title":"Isotope Effect on the Few-Femtosecond Relaxation Dynamics of the Ethylene Cation.","authors":"Matteo Lucchini, Manuel Cardosa-Gutierrez, Mario Murari, Fabio Frassetto, Luca Poletto, Mauro Nisoli, Francoise Remacle","doi":"10.1021/acs.jpca.5c01020","DOIUrl":"10.1021/acs.jpca.5c01020","url":null,"abstract":"Few-femtosecond extreme-ultraviolet (EUV) pulses with tunable energy are employed to initiate the Jahn-Teller structural rearrangement in the ethylene cation. We report on a combined experimental and theoretical investigation of an unusual isotope effect on the low-energy competing H/D-loss and H2/D2-loss channels observed in the ultrafast dynamics induced by an EUV-pump pulse and probed by an infrared (IR) pulse. The relative production yields of C2D4+, C2D3+, and C2D2+ exhibit pronounced oscillations with a period of ∼50 fs as a function of the pump-probe delay, while the oscillatory patterns are less pronounced for C2H4+. By using surface hopping to model the nonadiabatic dynamics in the four lowest electronic states of the cation, we show that the enhanced oscillations in deuterated fragment yields arise from a synergy between the isotope effects on the wave packet relaxation through the network of conical intersections and on the vibrational frequencies of the cation.","PeriodicalId":59,"journal":{"name":"The Journal of Physical Chemistry A","volume":" ","pages":"3063-3070"},"PeriodicalIF":2.7,"publicationDate":"2025-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143707784","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}

引用次数: 0