The Journal of Physical Chemistry A最新文献

{"title":"Acidity Prediction in Arbitrary Solvents: Machine Learning Based on Semiempirical Molecular Orbital Calculation.","authors":"Rima Suzuki, Hirotoshi Mori","doi":"10.1021/acs.jpca.4c07367","DOIUrl":"10.1021/acs.jpca.4c07367","url":null,"abstract":"<p><p>Due to the nonlinearity of solvent effects, careful solvent selection is essential when using acids in different applications. However, there is a lack of measurements of p<i>K</i>_a while systematically changing molecular structures and solvents. Consequently, there was no protocol to predict the acidity in arbitrary environments. This study developed an arbitrary environment p<i>K</i>_a prediction protocol by integrating quantum chemical calculations using a polarizable continuum model and machine learning. This protocol constructed models to predict the acidity of biologically relevant molecules in water and candidate superstrong acids in organic solvents. For both systems, the p<i>K</i>_a can be predicted with an average absolute error of 1.1 by learning relatively small number of data. This approach can also account for the nonlinear decay of acidity with solvation in different environments (compression effect). The versatility of the protocol extends to its applicability to a wide range of compounds, including those with complex electronic state changes upon proton dissociation, supporting research in diverse fields including, but not limited to, drug discovery and engineering.</p>","PeriodicalId":59,"journal":{"name":"The Journal of Physical Chemistry A","volume":" ","pages":"2612-2617"},"PeriodicalIF":2.7,"publicationDate":"2025-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143497558","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":"Observation of a New TICT State during the Photophysical Process of an Al³⁺ Sensor.","authors":"Bingqing Sun, Lei Liu, Juyoung Yoon","doi":"10.1021/acs.jpca.4c07483","DOIUrl":"10.1021/acs.jpca.4c07483","url":null,"abstract":"<p><p>Schiff base with a C═N bond is widely used in the fabrication of turn-on sensors for cations. The isomerization of C═N is generally believed to induce a dark state and quenches the sensor's fluorescence. With the aid of time-dependent density functional theory (TDDFT), this contribution performs a comprehensive investigation on the photophysical process of a turn-on sensor for Al³⁺. The isomerization of C═N leads to a non-emissive twisted intramolecular charge transfer (TICT) state, which is initiated by an early stage excited state intramolecular proton transfer (ESIPT) process. However, this isomerization process has a very large energy barrier and low reaction rate that cannot effectively quench the sensor's fluorescence. Interestingly, a brand new non-emissive TICT state is observed which is not induced by the isomerization of C═N but by the rotation of a neighboring C-C bond. Due to the low rotation energy barrier, this new TICT state can be attained easily and opens up an effective channel for non-emissive decays. This observation implies that the excited state potential energy surface for sensors based on a Schiff base should be much more complicated than expected. Based on the photophysical process, the sensing mechanism for Al³⁺ as well as its selectivity in the face of interfering cations are uncovered.</p>","PeriodicalId":59,"journal":{"name":"The Journal of Physical Chemistry A","volume":" ","pages":"2420-2428"},"PeriodicalIF":2.7,"publicationDate":"2025-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143514118","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":"Automated Multireference Vertical Excitations for Transition-Metal Compounds.","authors":"Jacob J Wardzala, Daniel S King, Laura Gagliardi","doi":"10.1021/acs.jpca.4c08597","DOIUrl":"10.1021/acs.jpca.4c08597","url":null,"abstract":"<p><p>Excited states of transition metal complexes are generally strongly correlated due to the near-degeneracy of the metal d orbitals. Consequently, electronic structure calculations of such species often necessitate multireference approaches. However, widespread use of multireference methods is hindered due to the active space selection problem, which has historically required system-specific chemical knowledge and a trial-and-error approach. Here, we address this issue with an automated method combining the approximate pair coefficient (APC) scheme for estimating orbital entropies with the discrete variational selection (DVS) approach for evaluating active space quality. We apply DVS-APC to the calculation of 67 vertical excitations in transition metal diatomics as well as to two larger complexes. We show DVS-APC generated active spaces yield NEVPT2 mean absolute errors of 0.18 eV, in line with previous accuracies obtained for organic systems, but larger than errors achieved with hand-selected active spaces (0.14 eV). If instead of using DVS we identify the best results from our trial wave functions, we find improved performance (mean absolute error of 0.1 eV) over the manually selected results. We highlight this deviation between DVS and hand selected active spaces as a possible measure of bias introduced when hand selecting active spaces. However, we find that multiconfiguration pair-density functional theory (MC-PDFT) using the tPBE and tPBE0 functionals is roughly 0.15 eV less accurate than NEVPT2 across this class of diatomic systems, potentially accounting for the decreased performance of DVS-APC, which uses MC-PDFT energies to select between active spaces. We also showcase an ability to \"down-sample\" the DVS-APC wave functions using natural orbital occupancies to achieve smaller minimal active spaces which retain the accuracy of the larger starting active spaces. Finally, DVS-APC and tPBE0 are proven to be effective when applied to modeling excited states in two larger transition metal complexes, suggesting that the transition metal diatomics may be a particular outstanding challenge for DVS-APC and MC-PDFT approaches.</p>","PeriodicalId":59,"journal":{"name":"The Journal of Physical Chemistry A","volume":" ","pages":"2683-2691"},"PeriodicalIF":2.7,"publicationDate":"2025-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143539373","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":"Theoretical Exploration of the Effects of Conjugated Side Chains on the Photoelectric Properties of Y6-Based Nonfullerene Acceptors","authors":"Xingyu Xie,&nbsp;Zhiyun Chen and Shaohui Zheng*,&nbsp;","doi":"10.1021/acs.jpca.4c0858710.1021/acs.jpca.4c08587","DOIUrl":"https://doi.org/10.1021/acs.jpca.4c08587https://doi.org/10.1021/acs.jpca.4c08587","url":null,"abstract":"<p >With the application of nonfullerene acceptors (NFAs) Y6 and its derivatives, the power conversion efficiencies (PCEs) of single-junction organic solar cells (OSCs) have exceeded 20%. Side-chain engineering has proven to be an important strategy for optimizing Y6-based NFAs. However, studies on the incorporation of conjugated side chains into Y6-based NFAs are still rare, and the corresponding underlying mechanisms are still not well understood. In this article, we systematically designed eight molecules based on modifications to the conjugated side chains of two reported Y6-based NFAs, involving alterations of branched alkyl chains at different positions on the thiophene, benzene, bithiophene, and benzene-thiophene moieties that serve as conjugated side chains. Using reliable density functional theory (DFT) and time-dependent DFT calculations, we obtained key photovoltaic parameters such as molecular planarity, dipole moments, electrostatic potential and corresponding fluctuations, frontier molecular orbitals, exciton binding energy (<i>E</i>_b), singlet–triplet energy differences (Δ<i>E</i>_<i>ST</i>), and UV–vis absorption spectra of these newly designed NFAs. The results show that the side conjugated rings and the positions of lateral alkyl chains attached to these rings exert noticeable influences on their photoelectric properties. Notably, compared to the prototype T3EH, 2T2EH, 2T3EH, PT2EH, PT3EH, and P2EH exhibit enhanced absorption (manifesting as increased total oscillator strength) and smaller <i>E</i>_b and Δ<i>E_ST</i> values, hinting at their promising potential as novel NFAs.</p>","PeriodicalId":59,"journal":{"name":"The Journal of Physical Chemistry A","volume":"129 12","pages":"2866–2875 2866–2875"},"PeriodicalIF":2.7,"publicationDate":"2025-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143703855","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":"Infrared Spectroscopy of [H2O–N2O]+-(H2O)n (n = 1 and 2): Microhydration Effects on the Hemibond","authors":"Tatsuki Hosoda,&nbsp;Mizuhiro Kominato and Asuka Fujii*,&nbsp;","doi":"10.1021/acs.jpca.5c0042810.1021/acs.jpca.5c00428","DOIUrl":"https://doi.org/10.1021/acs.jpca.5c00428https://doi.org/10.1021/acs.jpca.5c00428","url":null,"abstract":"<p >The hemibond, a nonclassical covalent bond involving three electrons shared between two centers, has attracted considerable attention due to its significance in radiation chemistry. Water radical cation clusters, [H₂O–X]⁺, exhibit two primary bonding motifs: the hemibond and the hydrogen bond. Although hydrogen bond formation typically dominates, recent studies have identified instances of hemibond formation in some systems involving water molecules. This study focuses on the [H₂O–N₂O]⁺ radical cation cluster, a rare system exhibiting hemibond formation. We investigate the stability of this hemibond in [H₂O–N₂O]⁺ against microhydration by employing infrared photodissociation spectroscopy and conducting theoretical calculations on [H₂O–N₂O]⁺-(H₂O)_<i>n</i> (<i>n</i> = 1 and 2). By comparing experimental and simulated spectra, we determined the predominant intermolecular bonding motifs in [H₂O–N₂O]⁺-(H₂O)_<i>n</i> (<i>n</i> = 1 and 2). Our analysis revealed that proton-transferred-type isomers are almost exclusively populated for <i>n</i> = 1 and 2, whereas hemibonded-type isomers are energetically unfavorable. These findings indicate that microhydration disrupts the hemibond and shifts the stable structural motifs.</p>","PeriodicalId":59,"journal":{"name":"The Journal of Physical Chemistry A","volume":"129 12","pages":"2896–2902 2896–2902"},"PeriodicalIF":2.7,"publicationDate":"2025-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143703852","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":"Demonstration of Intermolecular Triplet–Singlet FRET in Dye-Doped PVA Films at Room Temperature","authors":"Bong Lee*,&nbsp;Ignacy Gryczynski and Zygmunt Gryczynski,&nbsp;","doi":"10.1021/acs.jpca.5c0009610.1021/acs.jpca.5c00096","DOIUrl":"https://doi.org/10.1021/acs.jpca.5c00096https://doi.org/10.1021/acs.jpca.5c00096","url":null,"abstract":"<p >We report the first observation of triplet–singlet resonance energy transfer at room temperature without involving the intersystem crossing process. Triplet (T₁) to singlet (S₁) Förster resonance energy transfer (FRET) has been measured at room temperature with a long-wavelength direct donor’s triplet-state excitation. The donor coumarin 106 (C106D) and acceptor rhodamine 101 (R101A) were embedded in thin poly(vinyl alcohol) (PVA) films. The direct excitation of the C106D triplet state was at 470 nm, well outside the absorption, which avoids the donor singlet-state excitation and its involvement in the FRET process. The intensity of C106D decreases in the presence of R101 and is accompanied by an increase of acceptor R101A emission. The observed FRET results in a red glow of the illuminated area lasting hundreds of milliseconds. The FRET measurements with direct triplet-state excitation can also be used to estimate the photophysical parameters of the donor triplet state.</p>","PeriodicalId":59,"journal":{"name":"The Journal of Physical Chemistry A","volume":"129 11","pages":"2734–2737 2734–2737"},"PeriodicalIF":2.7,"publicationDate":"2025-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143654282","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":"Revealing a Heavy-Atom Assisted Rotation Mechanism in the H + NH2Cl Multi-Channel Reaction","authors":"Yizhuo Chen,&nbsp;Zhao Tu,&nbsp;Jiaqi Li,&nbsp;Chuanxi Duan*,&nbsp;Hongwei Song* and Minghui Yang,&nbsp;","doi":"10.1021/acs.jpca.5c0041510.1021/acs.jpca.5c00415","DOIUrl":"https://doi.org/10.1021/acs.jpca.5c00415https://doi.org/10.1021/acs.jpca.5c00415","url":null,"abstract":"<p >Identifying atomic-level mechanisms in elemental chemical reactions is crucial for understanding complex reaction processes. This study focuses on the typical multichannel H + NH₂Cl reaction, which plays a significant role in environmental science. High-level ab initio calculations determined seven distinct reaction pathways, leading to three product channels: H₂ + NHCl, HCl + NH₂, and Cl + NH₃. A full-dimensional, globally accurate potential energy surface was constructed by fitting 143,333 ab initio energy points, calculated at the UCCSD(T)-F12a/aug-cc-pVTZ level. The atomic-level mechanisms of the reaction along these seven pathways were identified and visualized using quasi-classical trajectory calculations. Interestingly, a novel reaction mechanism, termed “heavy-atom assisted rotation”, was discovered. In this light-heavy-heavy reaction, the attacked heavy atom (either Cl or N) acts as a “gangplank”, propelling the light H atom in front of the other heavy atom through rotational motion. This mechanism results in forward and sideward scattering of products at small impact parameters, which contrasts with any known direct mechanisms.</p>","PeriodicalId":59,"journal":{"name":"The Journal of Physical Chemistry A","volume":"129 12","pages":"2887–2895 2887–2895"},"PeriodicalIF":2.7,"publicationDate":"2025-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143703730","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 “A Novel Approach for Quantifying Magnetic Susceptibility of Aqueous and Organic Solutions”","authors":"Konrad Wojtaszek*,&nbsp;Andrea Cristofolini,&nbsp;Arturo Popoli,&nbsp;Karolina Kolczyk-Siedlecka and Marek Wojnicki,&nbsp;","doi":"10.1021/acs.jpca.5c0094910.1021/acs.jpca.5c00949","DOIUrl":"https://doi.org/10.1021/acs.jpca.5c00949https://doi.org/10.1021/acs.jpca.5c00949","url":null,"abstract":"","PeriodicalId":59,"journal":{"name":"The Journal of Physical Chemistry A","volume":"129 11","pages":"2822 2822"},"PeriodicalIF":2.7,"publicationDate":"2025-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143654375","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":"Neutral Cyclic Nitreones: Electronic Structure Analysis Reveals an Unorthodox Perspective of Several Zwitterionic Heterocyclic Species","authors":"Astha Gupta,&nbsp;Pooja Saulanki and Prasad V. Bharatam*,&nbsp;","doi":"10.1021/acs.jpca.4c0823510.1021/acs.jpca.4c08235","DOIUrl":"https://doi.org/10.1021/acs.jpca.4c08235https://doi.org/10.1021/acs.jpca.4c08235","url":null,"abstract":"<p >Nitreones are compounds with the general formula L → N⁺ ← L′. These compounds exhibit medicinal properties and have found applications in phase transfer catalysis. A few nitreones are cyclic; protonated cycloguanil (an antimalarial agent) is the most prominent example. Recently, a few more cyclic compounds were experimentally reported, in which the central N⁺ was shown to exhibit nitreone character. This led to attention being paid to the chemistry of neutral cyclic nitreones. A thorough literature search led to two sets of cyclic nitreones: C → N ← C type and P → N ← P type. In this work, we report quantum chemical analysis in exploring the electronic structure of neutral cyclic nitreones. Molecular orbital analysis, electron density analysis, charge, electron localization function (ELF), complexation energy values, and Tolman electronic parameter (TEP) all indicate that the studied compounds do carry nitrogen in the N(I) oxidation state and the two lone pairs are at the central nitrogen; thus, they qualify to be considered as cyclic nitreones.</p>","PeriodicalId":59,"journal":{"name":"The Journal of Physical Chemistry A","volume":"129 12","pages":"2854–2865 2854–2865"},"PeriodicalIF":2.7,"publicationDate":"2025-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143703722","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":"A Class of Promising Merocyanine-Functionalized Cd33Se33 Quantum Dots with Strong Fluorescence Emission in Tetrahydrofuran and Acetonitrile","authors":"Yingxing Li,&nbsp;Chuanfang Zhao,&nbsp;Jinliang Ning,&nbsp;Haiming Duan* and Xincun Dou*,&nbsp;","doi":"10.1021/acs.jpca.5c0037810.1021/acs.jpca.5c00378","DOIUrl":"https://doi.org/10.1021/acs.jpca.5c00378https://doi.org/10.1021/acs.jpca.5c00378","url":null,"abstract":"<p >Owing to the existence of surface defects, quantum dots (QDs) could be unstable, and thus, the design of proper ligands to improve their stability and optical performance is challenging. In this work, four D-π-<i>A</i> ligands were designed by modulating the D part of merocyanine and were grafted onto Cd₃₃Se₃₃ QD via a Cd–S bond, forming Cd₃₃Se₃₃@D-π-<i>A</i> complexes. It was found that a hole trap appeared between the HOMO and LUMO of the Cd₃₃Se₃₃@D-π-<i>A</i> complexes in vacuum, and the stronger the electron-donating capability of the D part, the higher the activation energy of the trap, which disappeared in solvent environments. The ligand-to-metal charge transfer (LMCT) mechanism of Cd₃₃Se₃₃@D-π-<i>A</i> complexes induced a fluorescence quenching phenomenon in vacuum, while in solution, the local excitation on the D-π-<i>A</i> ligand facilitated stronger fluorescence due to the enhanced electron-donating capability of its D part. The present study provides a strategy for improving the optical performance of functional QDs through the design and optimization of D-π-<i>A</i> ligands, shedding light on the development and applications of novel functional QDs.</p>","PeriodicalId":59,"journal":{"name":"The Journal of Physical Chemistry A","volume":"129 11","pages":"2745–2753 2745–2753"},"PeriodicalIF":2.7,"publicationDate":"2025-03-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143654437","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}