The Journal of Physical Chemistry A最新文献

{"title":"Switchable Regioselectivity in Cs2CO3-Catalyzed (3 + 2) vs (3 + 4) Annulations of Aminoalkyl Esters with Azadienes: A DFT Study","authors":"Chunhui Liu,&nbsp;Xu Liu,&nbsp;Shixing Zhang,&nbsp;Zhifei Yang,&nbsp;Huijuan Han,&nbsp;Peilin Han","doi":"10.1021/acs.jpca.6c05000","DOIUrl":"https://doi.org/10.1021/acs.jpca.6c05000","url":null,"abstract":"<p>Spiro and fused skeletons are particularly noteworthyfor theirintriguing biological properties and their prevalence in natural productsand drug candidates. Although meaningful progress has been made inthe synthesis of these compounds, a comprehensive mechanistic understandingremains essential. In this study, we present a theoretical investigationof the competing mechanisms in Cs₂CO₃-catalyzed(3 + 2) versus (3 + 4) annulations involving aminoalkyl α,β-unsaturatedesters and azadienes. Our calculations reveal that for benzofuran-derivedazadienes, the (3 + 2) annulation is energetically favored over the(3 + 4) pathway, leading to spirocycles. In contrast, benzothiophene-derivedazadienes preferentially follow the (3 + 4) route to afford fuseddiazepines. The overall mechanism begins with Cs₂CO₃ deprotonating the relatively acidic N–H group of theaminoalkyl α,β-unsaturated ester to generate a nitrogenanion. This anion then nucleophilically attacks the azadiene, formingcarbanion and nitrogen anion intermediates, which subsequently divergeinto two pathways. In Pathway A, the carbanion intermediate undergoesα-regioselective (3 + 2) annulation, followed by protonationwith CsHCO₃ to yield spirobenzofurans. In Pathway B, thenitrogen anion intermediate undergoes γ-regioselective (3 +4) annulation, and subsequent protonation by CsHCO₃ givesthe seven-membered ring benzothiophene-diazepine product. To elucidatethe origin of the heteroatom-controlled regioselectivity, we employedthree complementary approaches: Parr functions (<em>P</em>_k^–) and local nucleophilicity indices(<em>N</em>_k) to assess the nucleophilicity ofthe competing reactive sites, and distortion/interaction analysisto dissect the energetic contributions. The results reveal that replacementof O by S modulates the nucleophilicity of the N1 and C2 sites inopposite directions. Moreover, the distortion/interaction analysisdemonstrates that the O → S substitution selectively increasesthe distortion energy for the (3 + 2) pathway but decreases it forthe (3 + 4) pathway, providing a quantitative physical origin forthe switchable regioselectivity. Collectively, these findings establisha complete mechanistic picture of the heteroatom-controlled regiodivergence.</p>","PeriodicalId":59,"journal":{"name":"The Journal of Physical Chemistry A","volume":"130 37","pages":"7432–7440"},"PeriodicalIF":3.0,"publicationDate":"2026-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148980796","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":"Correction to “Mechanistic Insights into the Cascade Reactivity of 1,6-Enynes with Arylsulfonyl Chlorides”","authors":"Selçuk Eşsiz","doi":"10.1021/acs.jpca.6c05822","DOIUrl":"https://doi.org/10.1021/acs.jpca.6c05822","url":null,"abstract":"","PeriodicalId":59,"journal":{"name":"The Journal of Physical Chemistry A","volume":"130 37","pages":"7531–7531"},"PeriodicalIF":3.0,"publicationDate":"2026-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148980749","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":"Polarizable Split-Charge Equilibration for Accurate Modeling of Nonbonded Interactions","authors":"Taehwan Jang,&nbsp;Minho M. Kim,&nbsp;Hoon Ryu,&nbsp;William A. Goddard, III,&nbsp;Hyungjun Kim","doi":"10.1021/acs.jpca.6c03021","DOIUrl":"https://doi.org/10.1021/acs.jpca.6c03021","url":null,"abstract":"<p>Accuratemodeling of nonbonded interactions remains challengingbecause conventional force fields often provide inadequate descriptionsof polarization and charge transfer. Here, we introduce a polarizablesplit-charge equilibration (PSQ) framework that combines localizedcharge flow with dipolar polarization, thereby mitigating the unphysicallong-range charge delocalization associated with polarizable charge-equilibrationmodels. To enable practical large-scale simulations, we develop anefficient PSQ implementation through algorithmic optimization andparallelization, achieving performance comparable to conventionalapproaches despite the model’s greater formal complexity. Wecombine PSQ with the universal nonbond potential for van der Waalsinteractions and an explicit four-body hydrogen-bond term to formthe PUxH framework. PUxH achieves near-chemical accuracy in predictingsmall-molecular pair interactions and accurately reproduces the bulkproperties of water, ammonia, and benzene. Overall, PUxH providesa transferable, physically grounded, and computationally efficientframework for modeling nonbonded interactions in molecular and condensed-phasesystems.</p>","PeriodicalId":59,"journal":{"name":"The Journal of Physical Chemistry A","volume":"130 37","pages":"7504–7516"},"PeriodicalIF":3.0,"publicationDate":"2026-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148985266","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":"Zinc-Group Element-Stabilized Boron Analogues of Cyclopropenyl Cation Featuring π Aromaticity","authors":"Xiao-han Yin,&nbsp;Yu-le Dou,&nbsp;Bing Yan,&nbsp;Zhong-hua Cui","doi":"10.1021/acs.jpca.6c03023","DOIUrl":"https://doi.org/10.1021/acs.jpca.6c03023","url":null,"abstract":"<p>Planarboron clusters often display π-bonding patterns analogousto those found in aromatic hydrocarbons, making them intriguing inorganiccounterparts of classical hydrocarbon systems. Herein, we report zinc-groupelement-stabilized boron analogues of the cyclopropenyl cation (C₃H₃⁺), formulated as M₃B₃⁺ (M = Zn, Cd, and Hg). Global minimum searchesreveal that these clusters adopt highly symmetric <em>D</em>_3<em>h</em> structures with a ¹A₁′ electronic ground state and exhibit pronounced dynamicstability. Chemical bonding analyses demonstrate that M₃B₃⁺ reproduces the fundamental bonding motifof the cyclopropenyl cation, consisting of covalent M-B interactionsand a three-center two-electron (3c–2e) π bond delocalizedover the B₃ core. The resulting π-electron systemsatisfies Hückel’s (4<em>n</em> + 2) rule, givingrise to π aromaticity, as supported by magnetic aromaticityindices. Notably, in M₃B₃⁺ (M = Znand Cd), the vertical <em>T</em>₁ excited states exhibit σ-antiaromaticity, highlighting an unusual aromaticityreversal upon electronic excitation.</p>","PeriodicalId":59,"journal":{"name":"The Journal of Physical Chemistry A","volume":"130 37","pages":"7336–7344"},"PeriodicalIF":3.0,"publicationDate":"2026-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148985312","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":"KiMecO: A Kinetic Mechanism Optimizer for Experimentally Constrained Master Equation Models","authors":"Clément Soulié,&nbsp;Judit Zádor,&nbsp;Leonid Sheps","doi":"10.1021/acs.jpca.6c04372","DOIUrl":"https://doi.org/10.1021/acs.jpca.6c04372","url":null,"abstract":"<p>Detailed chemical kinetic mechanismsare widely used to model complexgas-phase reactions in atmospheric and combustion chemistry, but areoften underconstrained. In those cases, model predictions may remainaccurate due to parameter error cancellation within the validationconditions, yet fail outside of that range. We introduce KiMecO, anuncertainty informed, master equation based kinetic mechanism optimizerthat constrains the rate coefficients of a submechanism against concentration–timeprofiles of multiple species across multiple conditions. It leveragesmachine learning and parallel computation to explore the sensitivemaster equation parameter space and yield physically consistent correlationsamong rate coefficients. We show that ensembles of master equationmodels are generally more robust than single models and enable uncertaintyanalysis of the optimized rate coefficients.</p>","PeriodicalId":59,"journal":{"name":"The Journal of Physical Chemistry A","volume":"130 37","pages":"7517–7530"},"PeriodicalIF":3.0,"publicationDate":"2026-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148980740","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":"E2(η6–Be6H6) (E = Si–Pb): Doubly Aromatic Inverse-Sandwich Complexes","authors":"Viviana Roman-Ventura,&nbsp;Dumer S. Sacanamboy,&nbsp;Williams García-Argote,&nbsp;Diego Inostroza,&nbsp;Luis Alvarez-Thon,&nbsp;Luis Leyva-Parra,&nbsp;William Tiznado","doi":"10.1021/acs.jpca.6c03758","DOIUrl":"https://doi.org/10.1021/acs.jpca.6c03758","url":null,"abstract":"<p>Wereport E₂(η⁶-Be₆H₆) (E═Si, Ge, Sn, Pb), a new family of doubly aromaticinverse sandwich clusters in which a tetrel diatomic is sandwichedbetween a beryllium hydride ring. All four members adopt a singlet <em>D</em>_6<em>h</em> global minimum, separatedfrom the nearest competing isomer by 31.3, 29.1, 19.8, and 8.4 kcal·mol^–1 for E═Si, Ge, Sn, and Pb, respectively, withlarge HOMO–LUMO gaps of 4.3–4.8 eV and dynamic stabilityconfirmed up to at least 500 K. The electronic structure is stronglypolarized: the tetrel atoms carry large negative charges (−2.1to −1.8 |e|) and interact with the Be₆H₆ ring through predominantly ionic but non-negligible covalent E–Becontacts, while the ring is sustained by six Be–H–Bethree-center two-electron bonds and the E₂ fragment retainssignificant E–E bonding character. A delocalized 6σ/6πbonding pattern spans the full inverse sandwich framework, and diatropicσ and π ring currents─with total ring-current strengthsof 15.6–19.5 nA·T^–1─confirm σ/πdouble Hückel aromaticity throughout the series. These resultsextend the Be₆H₆-based inverse sandwich familyto group 14 and show that the aromatic electron count in these systemsis governed by the electron-accepting capacity of the axial fragment.</p>","PeriodicalId":59,"journal":{"name":"The Journal of Physical Chemistry A","volume":"130 37","pages":"7394–7403"},"PeriodicalIF":3.0,"publicationDate":"2026-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148985171","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":"The Vibrational Raman Optical Activity of β-Propiolactone Derivatives Computed with Coupled-Cluster Theory","authors":"Mya S. Pederson,&nbsp;Luther D. Crum,&nbsp;Ethan J. Poncelet,&nbsp;Brendan M. Shumberger,&nbsp;T. Daniel Crawford,&nbsp;Rollin A. King","doi":"10.1021/acs.jpca.6c01773","DOIUrl":"https://doi.org/10.1021/acs.jpca.6c01773","url":null,"abstract":"<p>Vibrational Raman optical activity (VROA) is an information-richtechnique with which to explore the molecular stereochemistry of chiralmolecules. The molecular properties needed to model a VROA spectrumcan be computed using coupled-cluster (CC) theory. We report VROAspectra computed with CC theory in an origin-independent manner forthe first time, applying the approach to several derivatives of β-propiolactone(oxetan-2-one), a strained, four-membered heterocycle with naturallyoccurring derivatives exhibiting a variety of stereochemistries. Thespectra were theoretically benchmarked in several ways. First, a comparisonof VROA spectra computed using CC2 theory was made to evaluate theperformance of a large number of one-electron basis sets. Second,spectra computed with CC2 and CCSD were compared to gauge the effectivenessof the less costly CC2 method. Third, VROA spectra determined fromCC2 chiroptical tensors computed using different geometries and vibrationalHessians were compared with one another. Finally, VROA spectra forβ-propiolactones substituted with methyl, ethyl, and propylgroups were produced with CC2 using geometries and Hessians determinedby B3LYP/aug-cc-pVTZ computations. For structures monosubstitutedat the 3-position (adjacent to the carbonyl), an intense peak occursat ≈1130 cm^–1 corresponding largely to theC–C stretch between the ring and the alkyl substituent. Forstructures monosubstituted at the 4-position, a similar peak correspondinglargely to the C–C stretch between the ring and the substituentappears at ≈1115 cm^–1. For disubstitutedspecies of (3<em>S</em>,4<em>R</em>) stereochemistry,a mode involving ring-breathing motion and asymmetrical wagging ofthe H atoms on C3 and C4 (on the same side of the β-lactonering) produces a large negative signal at ≈1130 cm^–1. The overall spectrum is found to be dominated by the configurationat the 3-position and less sensitive to that at the 4-position. Theresults suggest that VROA can be productively employed to interrogatethe stereochemistry at the 3-position. Unfortunately, no clear VROAsignal was identified that characterizes the stereochemistry at the4-position in disubstituted species.</p>","PeriodicalId":59,"journal":{"name":"The Journal of Physical Chemistry A","volume":"130 37","pages":"7297–7311"},"PeriodicalIF":3.0,"publicationDate":"2026-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148985212","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":"The Open-Shell Organic Systems Database: Diverse CCSD(T)/CBS Reaction Energies for Assessing Density Functional Theory and Machine Learning Methods","authors":"Amir Karton","doi":"10.1021/acs.jpca.6c03915","DOIUrl":"https://doi.org/10.1021/acs.jpca.6c03915","url":null,"abstract":"<p>We present the Open-Shell Organic Systems (OSOS) database,a diversebenchmark set comprising 9934 atomization, isomerization, and H-abstractionenergies computed at the CCSD(T)/CBS limit via W1-F12 theory. Historically,large-scale data sets (e.g., QM9 and ANI-1x) have been heavily biasedtoward closed-shell species. The OSOS database addresses this gapby providing a diverse and accurate set of reaction energies dedicatedexclusively to organic doublet radical systems for benchmarking andtraining purposes. The data set covers the chemical space spannedby localized and delocalized organic radicals containing up to sevennon-hydrogen atoms (C, N, O, and F). The database consists of 3360radical total atomization energies, 3360 H-abstractions, 2292 H-shifts,and 922 constitutional isomerizations. We use this database to assessthe performance of density functional theory (DFT). We find that mostdensity functionals systematically overestimate radical atomizationenergies; therefore, the inclusion of dispersion corrections generallyleads to a deterioration in performance. Furthermore, delocalizedradicals present a significantly greater challenge for most DFT methodsthan localized species, leading to larger overestimations of theiratomization energies. For localized radicals, errors increase in theorder: O-centered &lt; C-centered &lt; N-centered. Remarkably, thedeep-learning meta-GGA Skala functional demonstrates exceptional accuracy,significantly outperforming conventional functionals across all rungsof Jacob’s Ladder and consistently achieving mean absolutedeviations below 1 kcal mol^–1 for the abstraction,shift, and isomerization reactions. The OSOS database establishesa rigorous standard to guide the development and validation of next-generationdensity functionals and machine-learning potentials for doublet radicals.</p>","PeriodicalId":59,"journal":{"name":"The Journal of Physical Chemistry A","volume":"130 37","pages":"7267–7282"},"PeriodicalIF":3.0,"publicationDate":"2026-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148985278","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":"Final-State-Resolved Dynamics of the OH + CH3OH Reaction from Full-Dimensional Quasi-Classical Trajectory Simulations","authors":"Kaisheng Song,&nbsp;Jun Li","doi":"10.1021/acs.jpca.6c03929","DOIUrl":"10.1021/acs.jpca.6c03929","url":null,"abstract":"<p>State-resolved dynamics of the OH + CH₃OHhydrogen-abstractionreaction, OH + CH₃OH → CH₂OH + H₂O (R1) and OH + CH₃OH → CH₃O+ H₂O (R2), has been investigated using full-dimensionalquasi-classical trajectory (QCT) calculations on a recently developedhigh-accuracy potential energy surface (PES). Selective single-quantumexcitation of five vibrational modes of CH₃OH and rotationalexcitation of the OH radical were considered over a collision-energyrange from 1 to 20 kcal/mol. Product internal state distributionsand energy partitioning were analyzed by the normal-mode analysis(NMA) method. The calculations show that both channels gradually approacha direct mechanism at high collision energies, with most of the availableenergy partitioned into product relative translation. Distinct product-statedistributions are observed for the two channels and are closely relatedto transition-state geometrical relaxation and kinematic constraints.Excitation of different reactant modes leads to pronounced mode-specificeffects. Rotational excitation mainly induces stereodynamical steeringeffects, while torsional excitation promotes energy transfer intolow-frequency bending modes through intramolecular vibrational redistribution(IVR). More importantly, excitation of the high-frequency O–Hand C–H stretching modes reveals strong anharmonic couplingand transient mode mixing in the transition-state region. In particular,the nominal spectator C–H stretching modes actively participatein the reaction dynamics and significantly enhance the vibrationalexcitation of the H₂O product. These results provide furtherinsight into mode-specific energy flow and nonstatistical dynamicsin polyatomic hydrogen-abstraction reactions.</p>","PeriodicalId":59,"journal":{"name":"The Journal of Physical Chemistry A","volume":"130 36","pages":"7127–7140"},"PeriodicalIF":3.0,"publicationDate":"2026-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148917575","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":"Tetroses as a Unique Benchmark for Gas-Phase Carbohydrates: From Cyclic Aldoses to Open-Chain Ketoses","authors":"Lina Uribe,&nbsp;Luigi Crisci,&nbsp;Federico Lazzari,&nbsp;Vincenzo Barone","doi":"10.1021/acs.jpca.6c04475","DOIUrl":"10.1021/acs.jpca.6c04475","url":null,"abstract":"<p>Tetroses are the smallest carbohydratesfor which covalenttopology,ring closure, and cooperative intramolecular OH···Ohydrogen bonding must be treated as a single structural problem. High-resolutiongas-phase rotational data anchor both cyclic aldose and open-chainketose motifs within this family, making tetroses an exacting testof whether the accuracy ladder developed for smaller hydrogen-bondedprototypes transfers to genuine carbohydrates. We combine rotationalconstants and diagnostic infrared markers through a composite strategyin which each observable is treated at the level that controls itsdominant error. Pair-natural-orbital coupled-cluster structures, combinedwith affordable anharmonic rotational corrections, reproduce the microwave-observed <span>d</span>-erythrose furanoses and the open-chain erythrulose conformerwith spectroscopic accuracy. A dual-level vibrational protocol suppliesdiagnostic band assignments for the observed species and predictiveinfrared markers for conformers that remain experimentally uncharacterized.The same structural diagnosis motivates a topology-corrected reconstructionbased on double-hybrid functionals, with covalent and calibrated H···Ocontact corrections redistributed through a weighted Cartesian framework.The resulting ladder is validated on <span>d</span>-erythrose and erythruloseand then used to provide search data for <span>d</span>-threose. The centraloutcome is that cyclic and open-chain tetroses can be described onthe same footing without a uniformly expensive treatment of everycontribution: bonds, interaction-driven hydrogen-bond motifs, andvibrational averaging are each assigned to the rung at which theirdominant error is controlled.</p>","PeriodicalId":59,"journal":{"name":"The Journal of Physical Chemistry A","volume":"130 36","pages":"7162–7176"},"PeriodicalIF":3.0,"publicationDate":"2026-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148917733","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}