化学•材料最新文献

{"title":"Acidity Scale in a Quaternary Phosphonium Ionic Liquid and Its Implication on Carbon Dioxide Absorption.","authors":"Zhen Wang,Qian-Hang Niu,Wei Liu,Yongjun Zheng,Pengju Ji","doi":"10.1021/acs.joc.5c00925","DOIUrl":"https://doi.org/10.1021/acs.joc.5c00925","url":null,"abstract":"In this work, an acidity scale that comprises 23 organic Brønsted acids of different structural and electronic features was established in a representative quaternary phosphonium ionic liquid (QPIL), i.e., [P4,4,4,16][OTf] (with water content of 100 ppm), by the UV-vis spectroscopic method. The established acidity scale ranges from 5.4 to 22.2, covers about 17 pK units. We found that [P4,4,4,16][OTf] has fairly good stability toward some very strong bases. Acidity comparisons and regression analyses among various solvents show that the counteranion of [P4,4,4,16][OTf] is freer than those of imidazolium-based counterparts, which governs the solvation behavior of the QPIL. With the established acidity scale, we also studied CO2 absorptions in QPILs. To investigate the CO2 absorption in QPILs, a series of anion-functionalized QPILs, i.e., [P4,4,4,16][X] were synthesized, and their absorption capacities and kinetics were measured. The results show that the maximum absorption capacity of [P4,4,4,16][X] is much greater than that of other types of ILs, and a more basic QPIL leads to a faster absorption rate and a higher absorption capacity. The kinetic profiles and correlation analysis suggest that the capacity and mechanism of CO2 absorption in [P4,4,4,16][X] are closely associated with the basicities of anions of these QPILs.","PeriodicalId":57,"journal":{"name":"Journal of Organic Chemistry","volume":"181 1","pages":""},"PeriodicalIF":4.354,"publicationDate":"2025-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144851294","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":"Surface modification of Fe-based catalysts for promoting highly selective linear α-olefin formation in Fischer-Tropsch synthesis","authors":"Xuejian Zhang ,&nbsp;Shuai Zhang ,&nbsp;Jie Liang ,&nbsp;Kangzhou Wang ,&nbsp;Xinhua Gao ,&nbsp;Qingxiang Ma ,&nbsp;Tian-Sheng Zhao ,&nbsp;Yurong He ,&nbsp;Jianli Zhang","doi":"10.1016/j.apcata.2025.120504","DOIUrl":"10.1016/j.apcata.2025.120504","url":null,"abstract":"<div><div>Fischer-Tropsch synthesis (FTS) is a pivotal technology for sustainable production of chemicals from non-fossil resources. However, the design of catalysts to tailor product distribution, particularly to enhance olefin selectivity, remains an enduring challenge. Herein, we report an iron-based catalyst modified with oxygen-containing groups, Fe₃O₄/HEC (hydroxyethyl group-modified), which demonstrates extraordinary catalytic performance in FTS without any alkali metal promoters. This catalyst exhibits high activity, achieving 41.36 % light olefin (C₂-C₄⁼) selectivity and an O/P ratio of 5.49. Meanwhile, the C₅⁺ hydrocarbon selectivity reaches 40.38 % (with 68.2 % linear α-olefins). The modified catalyst promotes the formation of iron carbides and facilitates the coupling of *CH_x to promote chain growth while suppressing secondary hydrogenation reactions, which is considered to account for the high selectivity toward olefins and heavy hydrocarbons.</div></div>","PeriodicalId":243,"journal":{"name":"Applied Catalysis A: General","volume":"707 ","pages":"Article 120504"},"PeriodicalIF":4.8,"publicationDate":"2025-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144852879","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":"Ultrafast and Ultraslow Proton-Transfer Dynamics Induced by Formic Acid Dimer Ionization.","authors":"Saroj Barik, Ester Livshits, Roi Baer, Daniel Strasser","doi":"10.1021/acs.jpca.5c02619","DOIUrl":"https://doi.org/10.1021/acs.jpca.5c02619","url":null,"abstract":"<p><p>Proton-transfer dynamics in hydrogen-bonded dimers are important for understanding debated mechanisms of radiation damage to DNA base pairs. Using coincidence photofragment imaging in ultrafast extreme-ultraviolet pump and near-IR probe experiments on the formic acid dimer, we observed a transient enhancement (150 fs) of the protonated monomer signal. This correlates with ab initio molecular dynamics simulations of the ionization induced dynamics, showing concerted proton transfer and dimer ring opening in a metastable dimer. Coincidence analysis revealed the ultraslow mechanism of the metastable dimer cation on the microsecond time scale. The ultraslow dynamics were attributed to a barrier for the structural rearrangement of the deprotonated moiety from an HCOO to an OCOH geometry. Moreover, ultraslow channels of protonated monomer ions to form H₃O⁺ + CO and H₂O + CHO⁺ were observed and interpreted as dissociation of hot photoions, involving nontrivial hydrogen migration.</p>","PeriodicalId":59,"journal":{"name":"The Journal of Physical Chemistry A","volume":" ","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144853934","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":"Is Tl+ an Analogue of K+? IR Spectroscopy of Tl+ and a Key Peptide of the Selectivity Filter in K+ Channels.","authors":"Satoru Tanabe,Keisuke Hirata,Koichi Tsukiyama,James M Lisy,Masaaki Fujii,Shun-Ichi Ishiuchi","doi":"10.1021/acs.jpclett.5c01660","DOIUrl":"https://doi.org/10.1021/acs.jpclett.5c01660","url":null,"abstract":"Elemental substitution of K+ with Tl+ is a powerful method for enhancing the structural analysis of biomolecules because of significant enhancement of sensitivity. Its validity has been explained by their similar physical properties; however, the chemical analogy between K+ and Tl+ is still under debate. This is of prime importance in K+ channels because of the controversy on the translocation mechanism of K+ provoked by single-crystal X-ray diffraction using Tl+ as a replacement. Here, we have applied cryogenic ion trap infrared laser spectroscopy to a key part of the K+ channel to address the question of chemical similarity between Tl+ and K+ where the conformational distribution of the ion-peptide complexes correlates with ion permeability. The conformations of Tl+ with a partial peptide of the K+ channel selectivity filter were revealed by combining vibrational spectroscopy and quantum chemical calculations. Upon K+ → Tl+ substitution, there is a change in the conformer population distributions, significantly different from permeable K+, but very close to that of impermeable Na+. This suggests that substantial differences may exist for the interactions of Tl+ and K+ in the K+ channel selectivity filter. This difference is rationalized by the changes in the ion-peptide interaction, as directly revealed from the vibrational spectra. The fundamental differences between Tl+ and the peptide indicate that the chemical behavior of Tl+ does not necessarily replicate that of K+, highlighting the need for caution in utilizing elemental substitution of K+ by Tl+ in spectroscopic and crystallographic analyses.","PeriodicalId":62,"journal":{"name":"The Journal of Physical Chemistry Letters","volume":"88 1","pages":"8621-8626"},"PeriodicalIF":6.475,"publicationDate":"2025-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144851033","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":"Annulative Coupling of β-Ketosulfoxonium Ylides, β-Ketothioamides, and Aldehydes: Access to Highly Functionalized Dihydrothiophenes.","authors":"Rahul Kumar Saini,Satyendra Kumar Pandey","doi":"10.1021/acs.joc.5c01156","DOIUrl":"https://doi.org/10.1021/acs.joc.5c01156","url":null,"abstract":"A one-pot strategy has been developed for the efficient synthesis of highly functionalized dihydrothiophenes using β-ketosulfoxonium ylides, β-ketothioamides, and aldehydes. This cascade process involves C(sp3)-H insertion, aldol condensation, and intramolecular 1,4-conjugate addition, forming C-S and C-C bonds efficiently. The method offers good to high yields, a broad substrate scope, structural diversity, and scalability. Additionally, its synthetic utility is demonstrated through further transformation into a thiophene derivative, highlighting its applicability in the construction of complex molecules.","PeriodicalId":57,"journal":{"name":"Journal of Organic Chemistry","volume":"39 1","pages":""},"PeriodicalIF":4.354,"publicationDate":"2025-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144851295","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":"Molecular Editing of Ketones Derived by Pro-aromatic of Dihydroquinazolinones.","authors":"Xiaoxiao Yang,Xinyue Ma,Chao Shu","doi":"10.1021/acs.joc.5c01115","DOIUrl":"https://doi.org/10.1021/acs.joc.5c01115","url":null,"abstract":"Ketones represent a vital class of feedstock chemicals in organic synthesis. Researchers have explored a versatile deacylation strategy utilizing ketones as radical precursors, involving activation through condensation with 2-aminobenzamide to form dihydroquinazolinones (DHQZ). This aromatization-driven deconstructive reaction of ketones offers an efficient approach for the selective construction of diverse bonds, including C-H/D, C-C (sp, sp2, sp3), C-F, C-S/Se, C-N, and C-Si under mild conditions. As a result, ketones have found widespread application in the rapid and efficient assembly of structurally complex molecules. This perspective highlights recent advances in this field, emphasizing product diversity, selectivity, and broad applicability, while providing detailed mechanistic insights.","PeriodicalId":57,"journal":{"name":"Journal of Organic Chemistry","volume":"24 1","pages":""},"PeriodicalIF":4.354,"publicationDate":"2025-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144851297","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":"Updated Guidance for Communicating PFAS Identification Confidence with Ion Mobility Spectrometry.","authors":"Anna K Boatman, Jessie R Chappel, Kaylie I Kirkwood-Donelson, Jonathon F Fleming, David M Reif, Emma L Schymanski, Julia E Rager, Erin S Baker","doi":"10.1021/acs.est.5c01354","DOIUrl":"https://doi.org/10.1021/acs.est.5c01354","url":null,"abstract":"<p><p>Over the past decade, global contamination from per- and polyfluoroalkyl substances (PFAS) has become apparent due to their detection in countless matrices worldwide, from consumer products to human blood to drinking water. As researchers implement nontargeted analyses (NTA) to more fully understand the PFAS present in the environment and human bodies, clear guidance is needed for consistent and objective reporting of the identified molecules. Confidence levels for small molecules analyzed and identified with high-resolution mass spectrometry (HRMS) have existed since 2014; however, unification of currently used levels and improved guidance for their application is needed due to inconsistencies in reporting and continuing innovations in analytical methods. Here, we (i) investigate current practices for confidence level reporting of PFAS identified with liquid chromatography (LC), gas chromatography (GC), and/or ion mobility spectrometry (IMS) coupled with HRMS and (ii) propose a simple, unified confidence level guidance that incorporates both PFAS-specific attributes and IMS collision cross section (CCS) values.</p>","PeriodicalId":36,"journal":{"name":"环境科学与技术","volume":" ","pages":""},"PeriodicalIF":11.3,"publicationDate":"2025-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144843817","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hygroscopic effect on fatigue behaviour of natural fibre reinforced thermoset and thermoplastic composites","authors":"Ali Moghimi-ardekani,&nbsp;Jianqun Hao,&nbsp;Jan Ivens,&nbsp;Aart Willem van Vuure","doi":"10.1016/j.compositesa.2025.109244","DOIUrl":"10.1016/j.compositesa.2025.109244","url":null,"abstract":"<div><div>This study evaluates the fatigue performance of various thermoset and thermoplastic composites reinforced with unidirectional flax fibre under hygroscopic conditions. Quasi-static testing was conducted to assess the impact of humidity on the mechanical modulus of these composites. The flexural and tensile testing results revealed that, at higher humidity levels (85%<!--> <!-->RH) compared to standard conditions (50%<!--> <!-->RH), flexural modulus exhibits a stronger drop than tensile modulus, likely due to compressive deformation. Moreover, the flax fibre composites incorporating thermoset matrices, including epoxy and partially bio-based unsaturated polyester, demonstrate a shorter fatigue life at 85%<!--> <!-->RH relative to 50%<!--> <!-->RH. In contrast, thermoplastic-based flax fibre composites, such as with POM, PA11, and MAPP matrices, show improved fatigue resistance as humidity increases from 50%<!--> <!-->RH to 85%<!--> <!-->RH. These findings are supported by creep tests, which reveal an increase in the creep lifespan of thermoplastic composites at higher humidity. Furthermore, the fatigue data reveal that residual strain, loss factor, and hysteresis energy increase with increasing humidity. Stiffness during fatigue diminishes at 85%<!--> <!-->RH compared to 50%<!--> <!-->RH, but it doesn’t degrade during the cycling.</div></div>","PeriodicalId":282,"journal":{"name":"Composites Part A: Applied Science and Manufacturing","volume":"199 ","pages":"Article 109244"},"PeriodicalIF":8.1,"publicationDate":"2025-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144858237","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}

{"title":"Transition and Regulation of MicroRNA Let-7a Conformation at the Membrane Interface by Different Ionic Solutions.","authors":"Yulu Du, Chao Zhu, Haoyu Xiao, Dongqi Liu, Jiawei Zhang, Wenhui Li, Wangting Lu, Hongjuan Zhang, Feng Wei","doi":"10.1021/acs.jpcb.5c01379","DOIUrl":"https://doi.org/10.1021/acs.jpcb.5c01379","url":null,"abstract":"<p><p>The Lethal 7 (Let-7) miRNA family is attracting more and more attention in recent decades due to its capability in post-transcriptional regulation and the modulation of various physiological and pathological processes. Yet, the underlying mechanism that controls the conformation and biofunctions of Let-7 molecules during their translocation in and out of the cell membrane is still elusive. In the present study, the sum frequency generation vibrational spectroscopy (SFG-VS), a second-order nonlinear spectroscopic technique, was applied to examine the interfacial behavior of Let-7a at the lipid membrane interface. By creating the lamellar membrane environment <i>in vitro</i> with different ionic solutions, we were able to capture conformational changes in the Let-7a molecule based on the SFG spectra collected from the membrane interface after the miRNA-membrane interaction. Our results indicate that the ribose guanosine (rG) residues and ribose uridine (rU) residues of the Let-7a molecule show versatile changes as the concentration of ionic solutions increases. The analysis results also indicate that the hydrogen-bonding networks around the Let-7a molecules are greatly changed by the salt as the concentration of the NaCl and CaCl₂ solutions increases. As NaCl and CaCl₂ solution concentrations rose during experiments, we noted a marked reconfiguration of the hydrogen-bonding network around Let-7a molecules, driven by strengthened interactions between salt ions, water molecules, and Let-7a's functional groups, disrupting the original network and altering its connectivity/stability. This research offers valuable molecular-level insights into the salt-dependent conformation and behavior changes of miRNA at the lamellar lipid membrane interface. These findings also provide new perspectives for miRNA-related therapy and may help researchers in the improvement of innovative and pertinent drug delivery systems.</p>","PeriodicalId":60,"journal":{"name":"The Journal of Physical Chemistry B","volume":" ","pages":""},"PeriodicalIF":2.9,"publicationDate":"2025-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144853955","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":"Pseudouridimycin Biosynthesis: Biochemical Characterization of the Glucose-Methanol-Choline (GMC) Family Oxidoreductase, PumI.","authors":"Krushnamurthy Pattanayakanahalli Henjarappa, Simita Das, Dhananjaya Giriraju, Suvamay Jana, Nilkamal Mahanta","doi":"10.1021/acs.biochem.5c00177","DOIUrl":"https://doi.org/10.1021/acs.biochem.5c00177","url":null,"abstract":"<p><p>Pseudouridimycin (PUM) is a <i>C</i>-nucleoside antibiotic that selectively inhibits bacterial RNA polymerase (RNAP) with remarkable potency. It binds to the nucleoside triphosphate (NTP) entry region in the RNAP active site by mimicking uridine-5'-triphosphate (UTP), thus blocking RNA synthesis in bacteria. Since PUM does not inhibit human RNAP, it presents a highly selective scaffold for clinical applications. Besides its unique mode of action, PUM's peptidyl <i>C</i>-nucleoside structure comprises a rare pseudouridine (PU) moiety linked to an <i>N</i>-hydroxylated dipeptide, which is crucial for binding interactions with RNAP. Recently, the biosynthetic gene cluster (BGC) and a putative pathway have been reported for PUM biosynthesis. However, the investigation of the biosynthetic enzymes is still in its infancy. Here, we report detailed biochemical characterization of a flavin-dependent glucose-methanol-choline (GMC) family oxidoreductase, PumI, from <i>Streptomyces rimosus</i> (SrPumI) through substrate scope, computational modeling, mutational, kinetic, and mechanistic studies. Our studies have indicated that PumI preferentially accepts the native <i>C</i>-nucleoside substrate (PU) over <i>N</i>-nucleosides and acts as a gatekeeper in PUM biosynthesis. Our mutational analysis identified two active site histidines (His454 and His455) and two asparagines (Asn90 and Asn499) in SrPumI as potential flavin-binding residues. We propose His455 as the critical base for initiating catalysis based on our biochemical experiments and bioinformatics analysis. Additionally, Gln297 and Met58 were found to be important for substrate (PU) coordination. Based on these experiments, a mechanism has been proposed for PumI. We believe this work will provide new insights into PUM biosynthesis, enabling pathway engineering to prepare novel PUM derivatives for prospective therapeutic applications.</p>","PeriodicalId":28,"journal":{"name":"Biochemistry Biochemistry","volume":" ","pages":""},"PeriodicalIF":3.0,"publicationDate":"2025-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144853974","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}