Journal of Physical Organic Chemistry最新文献

{"title":"Kinetics of Double-Bond Isomerizations Among 1-Octene and cis and trans Linear Internal Octenes on Dry Amberlyst15 Catalyst: Adsorbed Alcohol Becomes an Active Site","authors":"Jeffrey C. Gee,&nbsp;Karen W. Fulbright,&nbsp;Daniel H. Ess,&nbsp;Jyothish Joy","doi":"10.1002/poc.70026","DOIUrl":"https://doi.org/10.1002/poc.70026","url":null,"abstract":"<div>\u0000 \u0000 <p>The double-bond isomerization of 1-octene to an equilibrium distribution of all seven linear octene isomers on a dry Amberlyst15 catalyst was followed at 90°C using gas chromatography to resolve five of the seven isomers. The simplest kinetic models that fit observed data over several hours indicated that carbenium ions are likely intermediates in these isomerizations. The C2 octyl carbenium ion appeared to be more stable than the C3 and C4 octyl carbenium ions, leading to a lower equilibrium <i>trans</i> to <i>cis</i> ratio in 2-octene than in 3-octenes and 4-octenes. At equilibrium, [2-octyl carbenium ion] / [3-octyl carbenium ion] = 1.6. The octene adsorption coefficient for double-bond isomerization on this catalyst was 0.4–0.5, indicating a rather weak adsorption. However, the concurrent dimerization of octene to branched hexadecene isomers required an adsorption coefficient of ~40, indicating octene adsorbs onto two different types of sites on this catalyst. The primary alcohol 2-ethyl-1-hexanol was added to reaction mixtures to suppress octene dimerization, and the active isomerization site in this work was a molecule of 2-ethyl-1-hexanol adsorbed onto a supported sulfonic acid group of the initial resin. This new site was less active than the original acid site.</p>\u0000 </div>","PeriodicalId":16829,"journal":{"name":"Journal of Physical Organic Chemistry","volume":"38 8","pages":""},"PeriodicalIF":1.9,"publicationDate":"2025-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144492656","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Molecular Structure of Dicyclopentadiene by Gas-Phase Electron Diffraction and Theoretical Calculations","authors":"Valeriya A. Mukhina,&nbsp;Alexey V. Eroshin,&nbsp;Ilya S. Navarkin,&nbsp;Sergey A. Shlykov","doi":"10.1002/poc.70027","DOIUrl":"https://doi.org/10.1002/poc.70027","url":null,"abstract":"<div>\u0000 \u0000 <p>In this article, the structure of the free dicyclopentadiene (DCPD) molecule was studied for the first time by the gas-phase electron diffraction (GED) at 268 K supplemented by quantum chemical calculations (B3LYP and MP2 with the cc-pVTZ basis set). The possibility of transition between endo and exo isomers of DCPD was considered in the gas phase. Three models of the refinement of the experimental (GED) data were applied on the base of two harmonic force fields and molecular dynamic simulations. The theoretical and experimental geometric parameters of the endo isomer are presented. In addition, the geometric parameters of the exo isomer calculated by quantum chemistry are given.</p>\u0000 </div>","PeriodicalId":16829,"journal":{"name":"Journal of Physical Organic Chemistry","volume":"38 7","pages":""},"PeriodicalIF":1.9,"publicationDate":"2025-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144308872","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Density Functional Theory Study of the Reductive Removal of Epoxide Oxygen From Small Polycyclic Aromatic Hydrocarbon Surface","authors":"Hiroshi Kawabata,&nbsp;Hiroto Tachikawa,&nbsp;Masahiro Shinoda","doi":"10.1002/poc.70022","DOIUrl":"https://doi.org/10.1002/poc.70022","url":null,"abstract":"<div>\u0000 \u0000 <p>The conductivity of graphene oxide is significantly increases when it is reduced, and oxygen is removed. In this study, the mechanism of deoxygenation of the epoxide sites of small polycyclic aromatic hydrocarbons (PAHs) with triphenylphosphine (PPh₃) was investigated using DFT. When PPh₃ attacks the epoxide oxygen, the carbon–oxygen bond is immediately cleaved by electron transfer, and the oxygen is then abstracted to form triphenylphosphine oxide. The reaction was found to be single-step and different from that of three-membered ring ethers, which are not bound to PAHs. The activation energy for deoxygenation is approximately 20 kcal/mol, and the reaction is exothermic.</p>\u0000 </div>","PeriodicalId":16829,"journal":{"name":"Journal of Physical Organic Chemistry","volume":"38 7","pages":""},"PeriodicalIF":1.9,"publicationDate":"2025-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144292449","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Assessing the Aromaticity of Fluorinated Benzene Derivatives Using New Descriptors Based on the Distributed Multipole Analysis (DMA) Partition of the Electron Density","authors":"Nathália M. P. Rosa,&nbsp;Matheus Máximo-Canadas,&nbsp;Itamar Borges Jr","doi":"10.1002/poc.70024","DOIUrl":"https://doi.org/10.1002/poc.70024","url":null,"abstract":"&lt;p&gt;We investigated the impact of fluorination on the aromaticity of 12 benzene-based compounds using a recently proposed new set of six descriptors (ACS Omega 2025, 10, 14, 14157–1417) based on the distributed multipole analysis (DMA) partition of the electron density. These descriptors allow the quantification of electron delocalization, an observable property related to aromaticity, and were defined from the components of the DMA quadrupole moment tensor &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;Q&lt;/mi&gt;\u0000 &lt;mn&gt;2&lt;/mn&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt;$$ {boldsymbol{Q}}_2 $$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;, the first electric multipole moment with out-of-plane contributions. We found a decrease in aromaticity that is related to the electron-withdrawing inductive effects of fluorine substituents, which modify the electron density distribution on the ring, particularly in regions adjacent to the substituents. The analysis by the &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;Q&lt;/mi&gt;\u0000 &lt;mn&gt;2&lt;/mn&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt;$$ {boldsymbol{Q}}_2 $$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;-based aromaticity descriptors revealed a strong correlation between electron distribution and electronic delocalization in fluorinated systems, confirming that fluorine substituents directly affect the symmetry and uniformity of electronic delocalization. A linear relationship between the &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;Q&lt;/mi&gt;\u0000 &lt;mn&gt;2&lt;/mn&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt;$$ {boldsymbol{Q}}_{mathbf{2}} $$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; descriptors &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;Q&lt;/mi&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mn&gt;2&lt;/mn&gt;\u0000 &lt;mi&gt;zz&lt;/mi&gt;\u0000 &lt;mo&gt;,&lt;/mo&gt;\u0000 &lt;mtext&gt;origin&lt;/mtext&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt;$$ {Q}_{2 zz, origin} $$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; and the &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mtext&gt;NICS&lt;/mtext&gt;\u0000 &lt;mfenced&gt;\u0000 &lt;mn&gt;1&lt;/mn&gt;\u0000 &lt;/mfenced&gt;\u0000 &lt;mi&gt;zz&lt;/mi&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt;$$ NICS(1) zz $$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; and ring current strength ","PeriodicalId":16829,"journal":{"name":"Journal of Physical Organic Chemistry","volume":"38 7","pages":""},"PeriodicalIF":1.9,"publicationDate":"2025-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/poc.70024","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144256038","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Functionalization of Graphene Flake Surfaces With p-Substituted Phenyl Radicals: Estimation of Activation Energies From Hammett Substituent Constants","authors":"Hiroshi Kawabata,&nbsp;Hiroto Tachikawa,&nbsp;Masahiro Shinoda","doi":"10.1002/poc.70025","DOIUrl":"https://doi.org/10.1002/poc.70025","url":null,"abstract":"<div>\u0000 \u0000 <p>Chemical modification of flat graphene surfaces composed of pure sp² carbons is extremely challenging. In this study, we used density functional theory to investigate the addition of phenyl radical derivatives to the surface of graphene flakes and clarified the effect of the nature of the substituents on the activation energy using Hammett plots. Circumcoronene was used as a model for the graphene flakes, and 13 <i>para</i>-substituted phenyl radicals were used as radical species. The activation energy consists of the distortion energies of the graphene flakes and radical species and the interaction energy between the graphene flakes and radical species. The interaction energy is 30%–40% of the activation energy. The interaction energy between the nitrophenyl radical and graphene flake is 3.1 kcal/mol, 2.3 kcal/mol lesser than that between the <i>N,N</i>-dimethylamino-phenyl radical and graphene flake. As the electron-withdrawing properties of the substituents increase, the interaction energy decreases, and consequently, the activation energy decreases. Furthermore, natural energy decomposition analysis shows that the intermolecular interactions are stabilized by charge transfer and electrostatic interactions, the magnitudes of which increase when increasing the Hammett constants of the substituents.</p>\u0000 </div>","PeriodicalId":16829,"journal":{"name":"Journal of Physical Organic Chemistry","volume":"38 7","pages":""},"PeriodicalIF":1.9,"publicationDate":"2025-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144244722","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Reaction of N-Allenyl-1H-Pyrrole-2-Yl-Carbaldehydes With Hydroxylamine: A Quantum Chemical Insight Into the Mechanism and Substituent Influence","authors":"Alexander S. Bobkov,&nbsp;Nikita V. Teplyashin,&nbsp;Svetlana V. Martynovskaya,&nbsp;Andrey V. Ivanov,&nbsp;Nadezhda M. Vitkovskaya","doi":"10.1002/poc.70023","DOIUrl":"https://doi.org/10.1002/poc.70023","url":null,"abstract":"<div>\u0000 \u0000 <p>We report on a quantum chemical study (B2PLYP-D3BJ/6-311+G**//B3LYP/6-31+G*) of the mechanism of the reaction of <i>N</i>-allenyl-1<i>H</i>-pyrrole-2-yl-carbaldehydes with hydroxylamine in ethanol leading to pyrrolopyrazine oxides. The main focus is placed on unraveling the influence of the nature of the substituent in the fourth and fifth positions of the pyrrole ring on the kinetic characteristics of the key stages of the reaction, which are oximation and intramolecular cyclization. The aryl substituents are found to favor the reaction, in contrast to the alkyl substituents.</p>\u0000 </div>","PeriodicalId":16829,"journal":{"name":"Journal of Physical Organic Chemistry","volume":"38 7","pages":""},"PeriodicalIF":1.9,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144190644","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Fundamental Origin of the Polar Contribution to Heat Capacity Changes in Hydration in an Aqueous Solution","authors":"Maxim P. Evstigneev,&nbsp;Anastasiya O. Lantushenko","doi":"10.1002/poc.70021","DOIUrl":"https://doi.org/10.1002/poc.70021","url":null,"abstract":"&lt;div&gt;\u0000 \u0000 &lt;p&gt;The current understanding of the nature of the physical factors making up the experimentally measured heat capacity change (&lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mo&gt;∆&lt;/mo&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;C&lt;/mi&gt;\u0000 &lt;mi&gt;P&lt;/mi&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt;$$ Delta {C}_P $$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;) for hydration/solvation occurring with net-neutral solutes at equilibrium in an aqueous solution is based on a large body of experimental work done from 1970 to 2000 which postulates the leading role of the hydrophobic effect (HE) in &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mo&gt;∆&lt;/mo&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;C&lt;/mi&gt;\u0000 &lt;mi&gt;P&lt;/mi&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt;$$ Delta {C}_P $$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;. Other contributions have also been identified, but their relative role and nature are not well understood. In the present work, we provide a new insight into the nature of the fundamental terms contributing to &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mo&gt;∆&lt;/mo&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;C&lt;/mi&gt;\u0000 &lt;mi&gt;P&lt;/mi&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt;$$ Delta {C}_P $$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; for a wide variety of molecular processes in an aqueous solution. The crux of our findings is the identification of two leading physical factors, viz., the long known HE and the newly found non-specific solute-solvent van der Waals orientational interactions (Keesom force), making up the magnitude of experimental &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mo&gt;∆&lt;/mo&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;C&lt;/mi&gt;\u0000 &lt;mi&gt;P&lt;/mi&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt;$$ Delta {C}_P $$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; in a general case under the standard conditions of an aqueous solution, “classical” manifestation of HE and employing the model of a rigid net-neutral solute. As a consequence, one can now characterize the thermodynamic nature of various molecular interactions in a solution based on the level of &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mo&gt;∆&lt;/mo&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;C&lt;/mi&gt;\u0000 &lt;mi&gt;P&lt;/mi&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt;$$ Delta {C}_P $$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; from a single viewpoint, including the identification of the leading factor, understanding the interrelation of different factors, the interpretation of the sign of &lt;span","PeriodicalId":16829,"journal":{"name":"Journal of Physical Organic Chemistry","volume":"38 7","pages":""},"PeriodicalIF":1.9,"publicationDate":"2025-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144171926","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hierarchical Molecular Structure–Based Method to Estimate the Normal Boiling Point of Aliphatic Oxygen-Containing Organic Compounds","authors":"Jincan Long,&nbsp;Chao-Tun Cao,&nbsp;Chenzhong Cao","doi":"10.1002/poc.70020","DOIUrl":"https://doi.org/10.1002/poc.70020","url":null,"abstract":"<div>\u0000 \u0000 <p>In this work, a hierarchical molecular structure method (HMSM) was proposed to extract molecular descriptors. In this method, the molecular structure is divided into three hierarchies: the first hierarchy involves the contributions of the number of vertices (vertex number <i>m</i> and the sum of vertex number effect, <i>S</i>_VNE); the second hierarchy involves the contributions of the vertex skeleton (odd-even index, OEI, and intramolecular polarization effect index, IMPEI); and the third hierarchy involves the contributions of the functional group (polarization effect index, PEI, and group influencing factor, <i>G</i>_N). Using these six molecular descriptors, the normal boiling points (NBP) of aliphatic oxygen-containing organic compounds (AOCOCs), including alcohols, ethers, aldehydes, ketones, carboxylic acids, and esters, can be quantitatively correlated well. The results show that the average absolute percentage error (APPE) between the experimental and calculated NBP values for each series of AOCOCs is less than 1%. Based on the obtained QSPR models, the NBPs of some AOCOCs that have not been experimentally measured were predicted, including 14 alcohols, 25 ethers, 106 aldehydes, 72 ketones, 103 carboxylic acids, and 57 esters. Additionally, a QSPR model for all 518 AOCOCs was also derived, yielding an APPE value of only 1.35%, indicating that the HMSM-based QSPR model performs exceptionally well in the field of QSPR modeling. The specific contributions of functional groups to NBP were discussed and their order is as follows: <span></span>COOH &gt; <span></span>OH &gt; <span></span>COO<span></span> &gt; <span></span>C(O)<span></span> &gt; <span></span>CHO &gt; <span></span>O<span></span>.</p>\u0000 </div>","PeriodicalId":16829,"journal":{"name":"Journal of Physical Organic Chemistry","volume":"38 7","pages":""},"PeriodicalIF":1.9,"publicationDate":"2025-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144171873","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"In-Depth Insights Into the Excited State Intramolecular Proton Transfer of Biologically Active Triazene Derivatives of Oxazole","authors":"Ritu Payal,&nbsp;Manju K. Saroj,&nbsp;Sapan Kumar Jain,&nbsp;R. C. Rastogi","doi":"10.1002/poc.70018","DOIUrl":"https://doi.org/10.1002/poc.70018","url":null,"abstract":"<div>\u0000 \u0000 <p>Phenyltriaz-1-en-1-yl-4-phenyloxazoles (PTOs) have been identified as photoinduced tautomeric photophysical probes. A series of PTOs has been synthesized and studied for their absorption and fluorescence spectral behavior in different solvent media with varying polarities. PTOs exhibited dual fluorescence behavior and large Stoke's shifts suggesting the presence of tautomeric forms (N* and T*). Dipole moments of PTOs in their excited states were calculated using Bakhshiev, Lippert–Mataga, Reichardt, and Kawski solvatochromic shift methods and were correlated with the theoretical dipole moments for N* and T* forms. The frontier molecular orbitals (HOMO-LUMO) and various physicochemical parameters (χ, η, σ, μ_p, ω, ΔE^II, N_max) were calculated using density functional theory (ground state-(CIS)/B3LYP/6–311++G(d,p)) computations to analyze the excited state intramolecular proton transfer (ESIPT) within these probes. The electrostatic potential (ESP) maps and Mulliken/NBO charges established the electrophilic and nucleophilic sites within molecules and intramolecular proton transfer from one end of the triazeno-bridge to the other end. DFT incorporated dispersion correction (D3(BJ)) accounts for significant van der Waals interactions. In vitro antioxidant activity of PTOs studied using 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assay revealed them as potential antioxidants. Two multi-parametric scales based on solvent polarity, namely, (i) Catálan and (ii) Abboud-Kamlet-Taft, were employed to analyze the acidity and basicity of PTOs in ground and excited states to provide a plausible mechanism for ESIPT.</p>\u0000 </div>","PeriodicalId":16829,"journal":{"name":"Journal of Physical Organic Chemistry","volume":"38 6","pages":""},"PeriodicalIF":1.9,"publicationDate":"2025-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143939549","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Computational Insight to Stereochemical Control on Conjugate Addition of Pyrroloalkenyl Thiol on Activated Alkyne","authors":"Akankasha Yadav,&nbsp;Sunita Siyak,&nbsp;Neelima Gupta","doi":"10.1002/poc.70019","DOIUrl":"https://doi.org/10.1002/poc.70019","url":null,"abstract":"<div>\u0000 \u0000 <p>[3+2] Cycloaddition reaction of thiazolium ylide with activated acetylene does not yield the expected pyrrolothiazole, in contrast to a similar reaction of other <i>N</i>-cycloiminium ylides. Initially formed [3+2] cycloadduct undergoes thiazole ring opening followed by a thiol-yne type nucleophilic addition on second molecule of activated alkyne to give <i>E</i>,<i>Z</i> and/or <i>Z</i>,<i>Z</i> isomers of 1:2 adduct. We have investigated the reaction of thiazolium ylides with alkyl propiolate computationally at DFT level to understand the impact of stereochemical control on mechanistic aspects. Relatively more stable conformer of thiazolium ylide leads to a thermodynamically as well as kinetically preferred diastereomer of the cycloadduct having <i>trans</i> orientation of hydrogen atoms, which restricts the auto-oxidation and facilitates the ring opening. Formation of the <i>Z</i> or <i>E</i> isomer in subsequent thiol-yne reaction depends on the stereochemical control of the allene or allenoate intermediate. Experimentally observed reactivity of thiazolium ylide is computationally rationalized on the basis of the CDFT-based reactivity indices and the stereochemical control on reaction mechanism.</p>\u0000 </div>","PeriodicalId":16829,"journal":{"name":"Journal of Physical Organic Chemistry","volume":"38 6","pages":""},"PeriodicalIF":1.9,"publicationDate":"2025-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143914353","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}