Journal of Physical Organic Chemistry最新文献

Enhanced Hyperpolarizabilities Through p‐Phenylene Bridges: Computational Studies on Metamerism and Functional Molecular Properties of Pyridinium–Dicyanomethanide‐Based Zwitterions 通过对苯桥增强超极化能力：关于吡啶鎓-二氰基甲烷基偶聚物的同素异形体和功能分子特性的计算研究

IF 1.8 4区化学 Q2 CHEMISTRY, ORGANIC

Journal of Physical Organic Chemistry

Pub Date : 2024-09-10 DOI: 10.1002/poc.4657

Sanyasi Sitha

Para‐phenylene‐bridged pyridinium (acceptor)–dicyanomethanide (donor)‐based zwitterions were computationally investigated and are reported here. Reichardt's metamer was found to be twisted and Brooker's metamer in near‐planar conformation. Natural bond orbital (NBO) analysis showed that mesomeric resonance is helping Brooker's metamer but found to be not helpful for Reichardt's metamer. To assess the impacts of metamerism and aromatic bridges, fundamental molecular properties like dipole moments (μ), polarizabilities (α), hyperpolarizabilities (β), and adiabatic absorptions of these two molecules were analyzed and then directly compared with their counterpart zwitterions without any bridges (previously reported). Results of impact of metamerism: Reichardt's metamer showed around three times enhanced hyperpolarizabilities (ωB97xD: β = 1577.1 × 10−30 esu) than the Brooker's metamer (ωB97xD: β = 532.5 × 10−30 esu). Impacts of p‐phenylene bridges: Compared to their respective D–A directly connected zwitterions reported previously (in ωB97xD methodology, Reichardt's: β = 257.2 × 10−30 esu and Brooker's: β = 67.2 × 10−30 esu), respective p‐phenylene‐bridged zwitterions showed five to eight times enhanced hyperpolarizabilities. This report highlights the better efficiencies of Reichardt's metamer over Brooker's metamer and aromatically bridged over the directly connected zwitterions. Current findings may be helpful in the designing of efficient functional molecular chromophores, and aromatic bridge combined with zwitterions can be solutions to nonlinear transparency trade‐off problem.

本文报告了基于对苯基桥接的吡啶鎓（受体）-二氰基甲烷鎓（供体）齐聚物的计算研究结果。研究发现，Reichardt 元胞是扭曲的，而 Brooker 元胞接近平面构象。自然键轨道（NBO）分析表明，介构共振有助于 Brooker 元共聚物，但对 Reichardt 元共聚物没有帮助。为了评估元共聚和芳香桥的影响，我们分析了这两种分子的基本分子性质，如偶极矩（μ）、极化率（α）、超极化率（β）和绝热吸收，然后将它们与没有任何桥的对应齐聚物（以前曾有报道）进行直接比较。元胞作用的影响结果：Reichardt 元聚体的超极化能力（ωB97xD: β = 1577.1 × 10-30 esu）比 Brooker 元聚体（ωB97xD: β = 532.5 × 10-30 esu）高出约三倍。对苯桥的影响：与之前报道的各自的 D-A 直接连接的三元共轭物相比（在 ωB97xD 方法中，Reichardt 的：β = 257.2 × 10-30 esu，Brooker 的：β = 67.2 × 10-30 esu），各自的对苯桥接三元共轭物的超极化能力提高了五到八倍。该报告强调了 Reichardt 元聚合体比 Brooker 元聚合体以及芳香桥接齐聚物比直接连接齐聚物的效率更高。目前的发现可能有助于设计高效的功能分子发色团，芳香桥与齐聚物的结合可以解决非线性透明度权衡问题。

{"title":"Enhanced Hyperpolarizabilities Through p‐Phenylene Bridges: Computational Studies on Metamerism and Functional Molecular Properties of Pyridinium–Dicyanomethanide‐Based Zwitterions","authors":"Sanyasi Sitha","doi":"10.1002/poc.4657","DOIUrl":"https://doi.org/10.1002/poc.4657","url":null,"abstract":"Para‐phenylene‐bridged pyridinium (acceptor)–dicyanomethanide (donor)‐based zwitterions were computationally investigated and are reported here. Reichardt's metamer was found to be twisted and Brooker's metamer in near‐planar conformation. Natural bond orbital (NBO) analysis showed that mesomeric resonance is helping Brooker's metamer but found to be not helpful for Reichardt's metamer. To assess the impacts of metamerism and aromatic bridges, fundamental molecular properties like dipole moments (μ), polarizabilities (α), hyperpolarizabilities (β), and adiabatic absorptions of these two molecules were analyzed and then directly compared with their counterpart zwitterions without any bridges (previously reported). Results of impact of metamerism: Reichardt's metamer showed around three times enhanced hyperpolarizabilities (ωB97xD: β = 1577.1 × 10−30 esu) than the Brooker's metamer (ωB97xD: β = 532.5 × 10−30 esu). Impacts of p‐phenylene bridges: Compared to their respective D–A directly connected zwitterions reported previously (in ωB97xD methodology, Reichardt's: β = 257.2 × 10−30 esu and Brooker's: β = 67.2 × 10−30 esu), respective p‐phenylene‐bridged zwitterions showed five to eight times enhanced hyperpolarizabilities. This report highlights the better efficiencies of Reichardt's metamer over Brooker's metamer and aromatically bridged over the directly connected zwitterions. Current findings may be helpful in the designing of efficient functional molecular chromophores, and aromatic bridge combined with zwitterions can be solutions to nonlinear transparency trade‐off problem.","PeriodicalId":16829,"journal":{"name":"Journal of Physical Organic Chemistry","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142191271","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}

引用次数: 0

In Memoriam: The Life and Scientific Accomplishments of Frank A. L. Anet (1926–2024) 悼念弗兰克-阿奈特（1926-2024）的生平与科学成就

IF 1.8 4区化学 Q2 CHEMISTRY, ORGANIC

Journal of Physical Organic Chemistry

Pub Date : 2024-08-26 DOI: 10.1002/poc.4656

Darón I. Freedberg, Nicholas V. Hud, Max Kopelevich, Daniel J. O'Leary, Jane Strouse

A memorial tribute detailing the life and scientific accomplishments of Frank A. L. Anet, a pioneer of nuclear magnetic resonance (NMR) spectroscopy who discovered bedrock principles in organic chemistry and magnetic resonance. He was the first to show that nuclear Overhauser effects could provide structural information, significantly impacting future NMR applications. In the 1960s and 1970s, he built entire multinuclear NMR spectrometers operating as high as 396 MHz for protons, detecting nuclei inaccessible to commercial instruments, and operating at very low temperatures for studying molecular structure and dynamics. A titan of physical organic chemistry, Frank made important contributions in the areas of conformational analysis, stereochemistry, isotope effects, NMR relaxation theory, and chemical origins of life.

弗兰克-阿奈特是核磁共振 (NMR) 光谱学的先驱，他发现了有机化学和磁共振的基本原理，这本纪念册详细介绍了他的生平和科学成就。他是第一个证明核奥弗霍塞尔效应可以提供结构信息的人，对未来的核磁共振应用产生了重大影响。20 世纪 60 年代和 70 年代，他建造了整个多核 NMR 光谱仪，质子的工作频率高达 396 兆赫，可探测商用仪器无法探测到的原子核，并可在极低的温度下工作，用于研究分子结构和动力学。作为物理有机化学的泰斗，弗兰克在构象分析、立体化学、同位素效应、核磁共振弛豫理论和生命的化学起源等领域做出了重要贡献。

引用次数: 0

Exploring Conformational Preferences in XC(W)ZY Molecules With X, Y = F, Cl, Br and W, Z = O, S, Se: Unraveling the Influence of Conjugative and Anomeric Interactions 探索 XC(W)ZY 分子中的构象偏好，其中 X、Y = F、Cl、Br 和 W、Z = O、S、Se：揭示共轭和同分异构相互作用的影响

IF 1.8 4区化学 Q2 CHEMISTRY, ORGANIC

Journal of Physical Organic Chemistry

Pub Date : 2024-08-12 DOI: 10.1002/poc.4654

Michelle T. Custodio Castro, Carlos O. Della Védova, Rosana M. Romano

The relative stabilities of the syn‐ and anti‐conformers of 72 molecules belonging to the XC(W)ZY type, with X, Y = F, Cl, Br and W, Z = O, S, Se, have been computed using the B3LYP/aug‐cc‐pVDZ approximation. The conformational preferences, represented by the energy differences between the two rotamers, exhibit a systematic trend in relation to both the halogen atoms and the chalcogen atoms. These computational predictions are in agreement with available experimental results. The NBO formalism was employed to assess the influence of both the conjugative and anomeric interactions on the relative energy of the conformers. It has been determined that the conjugative interaction provides a satisfactory explanation for the energy differences between rotamers. In contrast, the anomeric interactions favors the syn‐conformation in all cases. The relative stabilities between XC(W)ZY/YC(W)ZX and XC(W)ZY/XC(Z)WY constitutional isomers have also been computed and correlated with the experimental data.

采用 B3LYP/aug-cc-pVDZ 近似方法计算了 72 个 XC(W)ZY 型分子（X、Y = F、Cl、Br 和 W、Z = O、S、Se）的同构型和反构型的相对稳定性。由两个旋转体之间的能量差异所代表的构象优选性与卤素原子和查尔根原子的关系呈现出一种系统的趋势。这些计算预测与现有的实验结果一致。我们采用 NBO 形式来评估共轭作用和同分异构作用对构象相对能量的影响。结果表明，共轭作用可以令人满意地解释转构体之间的能量差异。相比之下，同分异构作用在所有情况下都有利于合成构象。此外，还计算了 XC(W)ZY/YC(W)ZX 和 XC(W)ZY/XC(Z)WY 构象异构体之间的相对稳定性，并将其与实验数据进行了关联。

{"title":"Exploring Conformational Preferences in XC(W)ZY Molecules With X, Y = F, Cl, Br and W, Z = O, S, Se: Unraveling the Influence of Conjugative and Anomeric Interactions","authors":"Michelle T. Custodio Castro, Carlos O. Della Védova, Rosana M. Romano","doi":"10.1002/poc.4654","DOIUrl":"https://doi.org/10.1002/poc.4654","url":null,"abstract":"The relative stabilities of the syn‐ and anti‐conformers of 72 molecules belonging to the XC(W)ZY type, with X, Y = F, Cl, Br and W, Z = O, S, Se, have been computed using the B3LYP/aug‐cc‐pVDZ approximation. The conformational preferences, represented by the energy differences between the two rotamers, exhibit a systematic trend in relation to both the halogen atoms and the chalcogen atoms. These computational predictions are in agreement with available experimental results. The NBO formalism was employed to assess the influence of both the conjugative and anomeric interactions on the relative energy of the conformers. It has been determined that the conjugative interaction provides a satisfactory explanation for the energy differences between rotamers. In contrast, the anomeric interactions favors the syn‐conformation in all cases. The relative stabilities between XC(W)ZY/YC(W)ZX and XC(W)ZY/XC(Z)WY constitutional isomers have also been computed and correlated with the experimental data.","PeriodicalId":16829,"journal":{"name":"Journal of Physical Organic Chemistry","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2024-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142191280","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}

引用次数: 0

Novel Trifunctional Intramolecular Frustrated Lewis Pair Derived From Aminoboronic Acid for Converting CO2 Into Valuable Chemicals 由氨基硼酸衍生的新型三官能团分子内受托路易斯对，可将二氧化碳转化为有价值的化学品

IF 1.8 4区化学 Q2 CHEMISTRY, ORGANIC

Journal of Physical Organic Chemistry

Pub Date : 2024-08-12 DOI: 10.1002/poc.4655

Mohmmad Faizan, Guntupalli Santhosh, Madhumita Chakraborty, Ravinder Pawar

The conversion of CO2 into valuable chemicals remains a significant challenge for achieving environmental sustainability, primarily due to the stability of the CO2 molecule. This necessitates the development of efficient and ecofriendly catalysts. In recent years, frustrated Lewis pairs (FLPs) have shown promise for CO2 utilization. In this study, we introduce α‐aminodiboronic acid (DBA), a novel trifunctional aminoboronic acid, as an intramolecular FLP for converting CO2 into cyclic carbonate and formic acid. Using density functional theory (DFT) calculations, we explored the reaction mechanism and investigated DBA's electronic structure through molecular electrostatic potential surface (MESP) and natural bond orbital (NBO) analyses. Our results reveal that one −B (OH)2 group induces an unusual state of frustration in the molecule due to charge transfer from the nitrogen atom's lone pair to the π* orbitals, enhancing catalytic performance. The additional −B (OH)2 group serves as an anchoring site for reactive species. The epoxide activation energy is reduced by approximately 27 kcal/mol compared to the uncatalyzed reaction, and the reduction of CO2 occurs with a requirement of 26 kcal/mol. The additional −B (OH)2 plays a crucial role in the catalytic mechanism and minimizes the energies of various structures observed in the reaction path. The reaction energetics align with structural analysis observations, marking this study as the first report on single‐molecule trifunctional FLPs for transforming CO2 into valuable chemicals.

主要由于二氧化碳分子的稳定性，将二氧化碳转化为有价值的化学品仍然是实现环境可持续性的重大挑战。这就需要开发高效、环保的催化剂。近年来，受挫路易斯对（FLPs）在二氧化碳利用方面显示出了前景。在本研究中，我们引入了α-氨基二硼酸（DBA）--一种新型的三官能氨基硼酸--作为分子内 FLP，用于将 CO2 转化为环碳酸盐和甲酸。利用密度泛函理论（DFT）计算，我们探索了反应机理，并通过分子静电位面（MESP）和天然键轨道（NBO）分析研究了 DBA 的电子结构。我们的研究结果表明，由于电荷从氮原子的孤对向π*轨道转移，一个-B (OH)2基团在分子中引起了一种不寻常的沮度状态，从而提高了催化性能。附加的 -B (OH)2 基团可作为反应物的锚定位点。与未催化反应相比，环氧化物的活化能降低了约 27 kcal/mol，而 CO2 的还原只需要 26 kcal/mol。附加的 -B (OH)2 在催化机理中起着关键作用，并使反应路径中观察到的各种结构的能量最小化。反应能量与结构分析观测结果一致，这标志着这项研究首次报道了将 CO2 转化为有价值化学品的单分子三功能 FLPs。

{"title":"Novel Trifunctional Intramolecular Frustrated Lewis Pair Derived From Aminoboronic Acid for Converting CO2 Into Valuable Chemicals","authors":"Mohmmad Faizan, Guntupalli Santhosh, Madhumita Chakraborty, Ravinder Pawar","doi":"10.1002/poc.4655","DOIUrl":"https://doi.org/10.1002/poc.4655","url":null,"abstract":"The conversion of CO2 into valuable chemicals remains a significant challenge for achieving environmental sustainability, primarily due to the stability of the CO2 molecule. This necessitates the development of efficient and ecofriendly catalysts. In recent years, frustrated Lewis pairs (FLPs) have shown promise for CO2 utilization. In this study, we introduce α‐aminodiboronic acid (DBA), a novel trifunctional aminoboronic acid, as an intramolecular FLP for converting CO2 into cyclic carbonate and formic acid. Using density functional theory (DFT) calculations, we explored the reaction mechanism and investigated DBA's electronic structure through molecular electrostatic potential surface (MESP) and natural bond orbital (NBO) analyses. Our results reveal that one −B (OH)2 group induces an unusual state of frustration in the molecule due to charge transfer from the nitrogen atom's lone pair to the π* orbitals, enhancing catalytic performance. The additional −B (OH)2 group serves as an anchoring site for reactive species. The epoxide activation energy is reduced by approximately 27 kcal/mol compared to the uncatalyzed reaction, and the reduction of CO2 occurs with a requirement of 26 kcal/mol. The additional −B (OH)2 plays a crucial role in the catalytic mechanism and minimizes the energies of various structures observed in the reaction path. The reaction energetics align with structural analysis observations, marking this study as the first report on single‐molecule trifunctional FLPs for transforming CO2 into valuable chemicals.","PeriodicalId":16829,"journal":{"name":"Journal of Physical Organic Chemistry","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2024-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142191319","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}

引用次数: 0

Theoretical investigations on N2H5N5/PDO cocrystal via a first‐principles study 通过第一原理研究对 N2H5N5/PDO 共晶体进行理论探索

IF 1.8 4区化学 Q2 CHEMISTRY, ORGANIC

Journal of Physical Organic Chemistry

Pub Date : 2024-08-12 DOI: 10.1002/poc.4653

Zhipeng Chen, Junqi Wang, Qingshan Xie, Chen Yang, Changlin Zhou

The exploration of cyclo‐N5ˉ‐based energetic cocrystals represents a noteworthy avenue within pentazolate chemistry, focusing on leveraging cocrystallization to enhance stability. Recently, a novel cocrystal explosive, N2H5N5/PDO, was developed by combining N2H5N5 with pyrazine 1,4‐dioxide (PDO), exhibiting promising detonation characteristics and reduced sensitivity. This study endeavors to elucidate how the structure and noncovalent interactions impact the performance of N2H5N5/PDO through a first‐principles investigation. The results indicate that the enhanced hydrogen bonding and wave‐like crystal packing structure within the cocrystal effectively bolster its stability compared to N2H5N5. The N···H and O···H interactions, in conjunction with π–π interactions, emerge as critical elements driving cocrystal formation. Compared to the pure N2H5N5, the detonation performance of the cocrystal exhibits a slight decline, albeit with a noticeable reduction in sensitivity.

对基于环 N5ˉ的高能共晶体的探索是五氮杂环化学中一个值得关注的领域，其重点是利用共晶化提高稳定性。最近，通过将 N2H5N5 与 1,4-二氧化吡嗪（PDO）结合，开发出一种新型共晶炸药 N2H5N5/PDO，显示出良好的引爆特性并降低了灵敏度。本研究试图通过第一原理研究，阐明结构和非共价相互作用如何影响 N2H5N5/PDO 的性能。结果表明，与 N2H5N5 相比，共晶体内增强的氢键和波状晶体堆积结构有效地提高了其稳定性。N--H和O--H相互作用以及π-π相互作用是驱动共晶体形成的关键因素。与纯 N2H5N5 相比，共晶体的引爆性能略有下降，但灵敏度明显降低。

{"title":"Theoretical investigations on N2H5N5/PDO cocrystal via a first‐principles study","authors":"Zhipeng Chen, Junqi Wang, Qingshan Xie, Chen Yang, Changlin Zhou","doi":"10.1002/poc.4653","DOIUrl":"https://doi.org/10.1002/poc.4653","url":null,"abstract":"The exploration of cyclo‐N5ˉ‐based energetic cocrystals represents a noteworthy avenue within pentazolate chemistry, focusing on leveraging cocrystallization to enhance stability. Recently, a novel cocrystal explosive, N2H5N5/PDO, was developed by combining N2H5N5 with pyrazine 1,4‐dioxide (PDO), exhibiting promising detonation characteristics and reduced sensitivity. This study endeavors to elucidate how the structure and noncovalent interactions impact the performance of N2H5N5/PDO through a first‐principles investigation. The results indicate that the enhanced hydrogen bonding and wave‐like crystal packing structure within the cocrystal effectively bolster its stability compared to N2H5N5. The N···H and O···H interactions, in conjunction with π–π interactions, emerge as critical elements driving cocrystal formation. Compared to the pure N2H5N5, the detonation performance of the cocrystal exhibits a slight decline, albeit with a noticeable reduction in sensitivity.","PeriodicalId":16829,"journal":{"name":"Journal of Physical Organic Chemistry","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2024-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142191320","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}

引用次数: 0

Torsional influences on cross‐conjugated thieno[3,4‐b]thiophene photochromes 扭转对交叉共轭噻吩并[3,4-b]噻吩光色团的影响

IF 1.8 4区化学 Q2 CHEMISTRY, ORGANIC

Journal of Physical Organic Chemistry

Pub Date : 2024-08-01 DOI: 10.1002/poc.4650

Nicholas P. Adams, John D. Tovar

Photoresponsive conjugated polymers are a promising target for modern organic electronics. Numerous photoswitchable repeat units have been included covalently within polymeric structures to enable responsive chromic materials, most commonly through side‐chain appendages or through formal conjugation along a π‐conjugated backbone. We recently disclosed a new design whereby the photoswitch elements are cross conjugated to a conjugated polymer main chain. In this case, we found that the extent of photoconversion was dictated in part by competitive main chain light absorption, which could be suppressed by using a photoswitching motif that carried most of the frontier molecular orbital densities. Here, we report the modeling and synthesis of a series of thieno[3,4‐b]thiophene (TT)‐based photochromes with various aromatic flankers imparting varying degrees of steric bulk and π‐conjugation in order to elucidate the balancing act between steric and electronic factors to promote photochromism. These model systems provide a better understanding of the behavior of photochromic units within extended oligomeric and polymeric π‐conjugated materials.

光致共振共轭聚合物是现代有机电子学的一个前景广阔的目标。人们在聚合物结构中以共价方式加入了许多光开关重复单元，以实现响应性色材料，最常见的方式是通过侧链附属物或沿着 π 共轭主链进行正式共轭。我们最近披露了一种新设计，即光电开关元件与共轭聚合物主链交叉共轭。在这种情况下，我们发现光电转换的程度部分取决于主链的竞争性光吸收，而通过使用携带大部分前沿分子轨道密度的光开关图案，可以抑制这种竞争性光吸收。在此，我们报告了一系列基于噻吩并[3,4-b]噻吩（TT）的光致变色剂的建模和合成，这些光致变色剂具有不同的芳香侧翼，赋予了不同程度的立体体积和π-共轭，从而阐明了立体因素和电子因素之间的平衡作用，以促进光致变色。通过这些模型系统，我们可以更好地了解扩展低聚物和聚合物 π 共轭材料中光致变色单元的行为。

{"title":"Torsional influences on cross‐conjugated thieno[3,4‐b]thiophene photochromes","authors":"Nicholas P. Adams, John D. Tovar","doi":"10.1002/poc.4650","DOIUrl":"https://doi.org/10.1002/poc.4650","url":null,"abstract":"Photoresponsive conjugated polymers are a promising target for modern organic electronics. Numerous photoswitchable repeat units have been included covalently within polymeric structures to enable responsive chromic materials, most commonly through side‐chain appendages or through formal conjugation along a π‐conjugated backbone. We recently disclosed a new design whereby the photoswitch elements are cross conjugated to a conjugated polymer main chain. In this case, we found that the extent of photoconversion was dictated in part by competitive main chain light absorption, which could be suppressed by using a photoswitching motif that carried most of the frontier molecular orbital densities. Here, we report the modeling and synthesis of a series of thieno[3,4‐b]thiophene (TT)‐based photochromes with various aromatic flankers imparting varying degrees of steric bulk and π‐conjugation in order to elucidate the balancing act between steric and electronic factors to promote photochromism. These model systems provide a better understanding of the behavior of photochromic units within extended oligomeric and polymeric π‐conjugated materials.","PeriodicalId":16829,"journal":{"name":"Journal of Physical Organic Chemistry","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141883605","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}

引用次数: 0

Theoretical study of atomic electronegativity effects on the excited‐state behavior of fluorescent compounds of citrinin 原子电负性对柠檬素荧光化合物激发态行为影响的理论研究

IF 1.8 4区化学 Q2 CHEMISTRY, ORGANIC

Journal of Physical Organic Chemistry

Pub Date : 2024-07-23 DOI: 10.1002/poc.4651

Yue Gao, Meiheng Lv, Zexu Cai, Yuhang Zhang, Tingting Wang, Jianyong Liu, Fangjian Shang, Wenze Li

The present work focuses on the light‐induced behavior of citrinin derivatives in relation to atomic electronegativity. A detailed theoretical study on the photophysical properties and excited‐state behavior of fluorescent compounds of citrinin (Cit‐O, Cit‐S, and Cit‐Se, with different atomic electronegativity) has been conducted, and the effect of electronegativity on the proton transfer in this system has been explained. First, the relevant hydrogen bond parameters and infrared vibrational spectra of the optimized geometrical configurations have been insightfully investigated. It is elucidated that the hydrogen bond is strengthened after photoexcitation, and it provides a driving force for excited‐state intramolecular proton transfer (ESIPT). In addition, the frontier molecular orbitals were analyzed, and the intramolecular charge transfer process in all Cit systems, the phenomenon of charge redistribution, facilitates the ESIPT reaction. By constructing potential energy surfaces for different transfer paths, the atomic electronegativity impact on the ESIPT dynamical behavior of the Cit system was determined. This work clarifies the mechanism of the intramolecular proton transfer process in the excited state of citrinin molecules and complements the theoretical study of the atomic electronegativity‐regulated citrinin system, which provides a corresponding theoretical basis for the design and synthesis of new luminescence‐adjustable citrinin systems.

本研究的重点是枸橼苷衍生物的光诱导行为与原子电负性的关系。研究人员对不同原子电负性的柠苦素荧光化合物（Cit-O、Cit-S 和 Cit-Se）的光物理性质和激发态行为进行了详细的理论研究，并解释了电负性对该体系中质子传递的影响。首先，深入研究了优化几何构型的相关氢键参数和红外振动光谱。结果表明，氢键在光激发后得到了加强，并为激发态分子内质子转移（ESIPT）提供了驱动力。此外，还分析了前沿分子轨道，所有 Cit 体系中的分子内电荷转移过程，即电荷再分布现象，促进了 ESIPT 反应。通过构建不同转移路径的势能面，确定了原子电负性对 Cit 体系 ESIPT 动力行为的影响。这项工作阐明了柠蛋白分子激发态分子内质子转移过程的机理，补充了原子电负性调控柠蛋白体系的理论研究，为设计和合成新的发光可调柠蛋白体系提供了相应的理论基础。

{"title":"Theoretical study of atomic electronegativity effects on the excited‐state behavior of fluorescent compounds of citrinin","authors":"Yue Gao, Meiheng Lv, Zexu Cai, Yuhang Zhang, Tingting Wang, Jianyong Liu, Fangjian Shang, Wenze Li","doi":"10.1002/poc.4651","DOIUrl":"https://doi.org/10.1002/poc.4651","url":null,"abstract":"The present work focuses on the light‐induced behavior of citrinin derivatives in relation to atomic electronegativity. A detailed theoretical study on the photophysical properties and excited‐state behavior of fluorescent compounds of citrinin (Cit‐O, Cit‐S, and Cit‐Se, with different atomic electronegativity) has been conducted, and the effect of electronegativity on the proton transfer in this system has been explained. First, the relevant hydrogen bond parameters and infrared vibrational spectra of the optimized geometrical configurations have been insightfully investigated. It is elucidated that the hydrogen bond is strengthened after photoexcitation, and it provides a driving force for excited‐state intramolecular proton transfer (ESIPT). In addition, the frontier molecular orbitals were analyzed, and the intramolecular charge transfer process in all Cit systems, the phenomenon of charge redistribution, facilitates the ESIPT reaction. By constructing potential energy surfaces for different transfer paths, the atomic electronegativity impact on the ESIPT dynamical behavior of the Cit system was determined. This work clarifies the mechanism of the intramolecular proton transfer process in the excited state of citrinin molecules and complements the theoretical study of the atomic electronegativity‐regulated citrinin system, which provides a corresponding theoretical basis for the design and synthesis of new luminescence‐adjustable citrinin systems.","PeriodicalId":16829,"journal":{"name":"Journal of Physical Organic Chemistry","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2024-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141774711","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}

引用次数: 0

Density functional theory study on frustrated Lewis pairs catalyzed C-H activation of heteroarenes: Mechanism variation tuning by electronic effect 关于受挫路易斯对催化的杂环烯 C-H 活化的密度泛函理论研究：电子效应对机理变化的调整

IF 1.9 4区化学 Q2 CHEMISTRY, ORGANIC

Journal of Physical Organic Chemistry

Pub Date : 2024-07-22 DOI: 10.1002/poc.4652

Youxiang Shao, Kang Xiao, Huize Wang, Yalan Liu

Unreactive C-H bond activation is a new horizon for frustrated Lewis pairs (FLPs) chemistry. Although concerted mechanism (Science 2015, 349, 513) and stepwise carbene mechanism (Org. Lett. 2018, 20, 1102) have been proposed for the FLPs catalyzed C-H bond activation of 1-methylpyrrole, the influence of electronic properties of FLPs on the reaction mechanism is far away from well-understood. In this study, an assortment of P-B type FLPs with different electronic characteristic was employed to study the catalyzed C-H bond activation of 1-methylpyrrole by using density functional theory calculations. Detailed calculations demonstrated that the reactivity variation and the reaction mechanism binary of FLPs catalyzed C-H activation can be varied by tuning electronic effect of Lewis base center. On the one hand, the concerted C-H activation reactivity is mainly controlled by the electron donation of the lone pair of Lewis base center; thus, the FLPs with electron-donating substituents (FLP1, FLP2, and FLP3) catalyzed the C-H bond activation through concerted mechanism. On the other hand, the reactivity of stepwise carbene mechanism is mostly attributed to the vacant orbital of Lewis acid center; as a result, the FLP5 bearing -P(C₆F₅)₂ preferred to catalyzed the bond activation through concerted mechanism. In contrast, a metathesis mechanism through strained four-membered ring transition state is less feasible. These results should provide deeper insight and broader perspective to understand the structure and function of FLPs for rational design of FLPs catalyzed C-H bond activation.

非反应性 C-H 键活化是受挫路易斯对（FLPs）化学的一个新视野。虽然已有人提出了FLPs催化1-甲基吡咯C-H键活化的协同机理（Science 2015, 349, 513）和逐步碳化机理（Org. Lett.本研究采用密度泛函理论计算方法，研究了多种具有不同电子特性的 P-B 型 FLPs 催化 1-甲基吡咯的 C-H 键活化反应。详细的计算结果表明，FLPs 催化 C-H 活化的反应活性变化和反应机理二元化可以通过调整路易斯碱中心的电子效应来实现。一方面，协同 C-H 活化反应活性主要受路易斯碱中心孤对电子捐献的控制；因此，具有电子捐献取代基的 FLPs（FLP1、FLP2 和 FLP3）通过协同机制催化 C-H 键活化。另一方面，逐步碳化机制的反应活性主要归因于路易斯酸中心的空闲轨道，因此，带有 -P(C6F5)2 的 FLP5 更倾向于通过协同机制催化键的活化。相比之下，通过应变四元环过渡态的偏合成机制则不太可行。这些结果将为我们深入了解 FLPs 的结构和功能，合理设计 FLPs 催化 C-H 键活化提供更广阔的视角。

{"title":"Density functional theory study on frustrated Lewis pairs catalyzed C-H activation of heteroarenes: Mechanism variation tuning by electronic effect","authors":"Youxiang Shao, Kang Xiao, Huize Wang, Yalan Liu","doi":"10.1002/poc.4652","DOIUrl":"10.1002/poc.4652","url":null,"abstract":"Unreactive C-H bond activation is a new horizon for frustrated Lewis pairs (FLPs) chemistry. Although concerted mechanism (Science 2015, 349, 513) and stepwise carbene mechanism (Org. Lett. 2018, 20, 1102) have been proposed for the FLPs catalyzed C-H bond activation of 1-methylpyrrole, the influence of electronic properties of FLPs on the reaction mechanism is far away from well-understood. In this study, an assortment of P-B type FLPs with different electronic characteristic was employed to study the catalyzed C-H bond activation of 1-methylpyrrole by using density functional theory calculations. Detailed calculations demonstrated that the reactivity variation and the reaction mechanism binary of FLPs catalyzed C-H activation can be varied by tuning electronic effect of Lewis base center. On the one hand, the concerted C-H activation reactivity is mainly controlled by the electron donation of the lone pair of Lewis base center; thus, the FLPs with electron-donating substituents (FLP1, FLP2, and FLP3) catalyzed the C-H bond activation through concerted mechanism. On the other hand, the reactivity of stepwise carbene mechanism is mostly attributed to the vacant orbital of Lewis acid center; as a result, the FLP5 bearing -P(C6F5)2 preferred to catalyzed the bond activation through concerted mechanism. In contrast, a metathesis mechanism through strained four-membered ring transition state is less feasible. These results should provide deeper insight and broader perspective to understand the structure and function of FLPs for rational design of FLPs catalyzed C-H bond activation.","PeriodicalId":16829,"journal":{"name":"Journal of Physical Organic Chemistry","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2024-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141774712","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}

引用次数: 0

Computational comparison of paratropicity trends in antiaromatic s‐indacene derivatives: Does the functional “make all the difference”? 计算比较反芳香族 s-indacene 衍生物的同位趋势：功能是否 "决定一切"？

IF 1.9 4区化学 Q2 CHEMISTRY, ORGANIC

Journal of Physical Organic Chemistry

Pub Date : 2024-07-16 DOI: 10.1002/poc.4648

Michael P. Miller, Michael M. Haley

A recent publication by Wu and co‐workers demonstrated that the workhorse functional B3LYP tends to overemphasize the delocalization in antiaromatic molecules, leading to poor agreement between the calculated proton NMR values and the experimentally obtained numbers. Rather, they showed that the M11 functional affords the best agreement between theory and experiment. We have computationally re‐examined our previously published NICS‐XY scan data using M11‐determined geometries and find that, aside from the placement of s‐indacene, the antiaromaticity trends for both sets of data are essentially identical.

Wu 及其合作者最近发表的一篇文章表明，工作主函数 B3LYP 往往会过度强调反芳香族分子中的脱ocalization，导致质子 NMR 计算值与实验所得数值之间的一致性很差。相反，他们发现 M11 函数能提供理论与实验之间的最佳一致性。我们使用 M11 确定的几何结构对之前发表的 NICS-XY 扫描数据进行了重新计算检查，发现除了 s-indacene 的位置外，两组数据的反芳香趋势基本相同。

引用次数: 0

Positive charge delocalization and anti-aromaticity of cations generated by protonation of benzo[a]fluoranthenes in superacid 苯并[a]荧蒽在超酸中质子化产生的阳离子的正电荷分散和反芳香性

IF 1.9 4区化学 Q2 CHEMISTRY, ORGANIC

Journal of Physical Organic Chemistry

Pub Date : 2024-07-14 DOI: 10.1002/poc.4647

Takao Okazaki, Haruki Yamashita, Toshikazu Kitagawa

Benzo[a]fluoranthene (4a) is one of non-alternate polycyclic aromatic hydrocarbons. A reaction of 4a in CF₃SO₃H yielded a dark yellow solution. Direct NMR observation indicated the exclusive formation of carbocation 4aH⁺ by protonation at the C(8) position. The most deshielded ¹H and ¹³C signals were observed at 8.99 ppm for H(12) and 8.29 ppm for H(1), 182.6 ppm for C(12b), 155.6 ppm for C(8a), and 149.4 ppm for C(7a). The signals for H(4) and H(5) were significantly more shielded than those of 4a. A reaction of 3-tert-butylbenzo[a]fluoranthene (4b) in CF₃SO₃H afforded carbocation 4bH⁺ by the protonation at the C(8) position. 4bH⁺ was gradually converted to 4aH⁺. The changes in ¹³C NMR chemical shifts (Δδ¹³C) suggested that positive charge was delocalized into mainly seven carbons in 4aH⁺ and 4bH⁺. The observed cations were found to be the most stable cations among the possible protonation cations by the DFT method. The NICS(1)_zz values for the five-membered rings were calculated to be 35.6 for 4aH⁺ and 34.4 for 4bH⁺ by GIAO-B3LYP/6-311+G(2d,p). The experimental NMR and the NICS(1)_zz data indicated that the five-membered rings in 4aH⁺ and 4bH⁺ exhibited anti-aromaticity.

苯并[a]荧蒽（4a）是一种非替代性多环芳烃。4a 在 CF3SO3H 中反应生成深黄色溶液。直接核磁共振观察表明，C（8）位上的质子化作用只形成了碳位 4aH+。在 8.99 ppm（H(12)）和 8.29 ppm（H(1)）、182.6 ppm（C(12b)）、155.6 ppm（C(8a)）和 149.4 ppm（C(7a)）处观察到了最去屏蔽的 1H 和 13C 信号。H(4) 和 H(5) 信号的屏蔽程度明显高于 4a 信号。3- 叔丁基苯并[a]荧蒽（4b）在 CF3SO3H 中发生反应，C(8)位质子化产生了碳位 4bH+。4bH+ 逐渐转化为 4aH+。13C NMR 化学位移（Δδ13C）的变化表明，正电荷主要分散到 4aH+ 和 4bH+ 的七个碳中。通过 DFT 方法发现，所观察到的阳离子是可能的质子化阳离子中最稳定的阳离子。通过 GIAO-B3LYP/6-311+G(2d,p) 方法计算出的五元环的 NICS(1)zz 值为：4aH+ 为 35.6，4bH+ 为 34.4。实验核磁共振和 NICS(1)zz 数据表明，4aH+ 和 4bH+ 中的五元环具有反芳香性。

{"title":"Positive charge delocalization and anti-aromaticity of cations generated by protonation of benzo[a]fluoranthenes in superacid","authors":"Takao Okazaki, Haruki Yamashita, Toshikazu Kitagawa","doi":"10.1002/poc.4647","DOIUrl":"10.1002/poc.4647","url":null,"abstract":"Benzo[a]fluoranthene (4a) is one of non-alternate polycyclic aromatic hydrocarbons. A reaction of 4a in CF3SO3H yielded a dark yellow solution. Direct NMR observation indicated the exclusive formation of carbocation 4aH+ by protonation at the C(8) position. The most deshielded 1H and 13C signals were observed at 8.99 ppm for H(12) and 8.29 ppm for H(1), 182.6 ppm for C(12b), 155.6 ppm for C(8a), and 149.4 ppm for C(7a). The signals for H(4) and H(5) were significantly more shielded than those of 4a. A reaction of 3-tert-butylbenzo[a]fluoranthene (4b) in CF3SO3H afforded carbocation 4bH+ by the protonation at the C(8) position. 4bH+ was gradually converted to 4aH+. The changes in 13C NMR chemical shifts (Δδ13C) suggested that positive charge was delocalized into mainly seven carbons in 4aH+ and 4bH+. The observed cations were found to be the most stable cations among the possible protonation cations by the DFT method. The NICS(1)zz values for the five-membered rings were calculated to be 35.6 for 4aH+ and 34.4 for 4bH+ by GIAO-B3LYP/6-311+G(2d,p). The experimental NMR and the NICS(1)zz data indicated that the five-membered rings in 4aH+ and 4bH+ exhibited anti-aromaticity.","PeriodicalId":16829,"journal":{"name":"Journal of Physical Organic Chemistry","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2024-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141650513","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}

引用次数: 0