Structural Chemistry最新文献

{"title":"Rational design of multi-sided Y-shaped triazine derivatives with enhanced NLO response via charge transfer dynamics and solvent engineering","authors":"Shabbir Muhammad,&nbsp;Sadia Riaz,&nbsp;Shafiq urRehman,&nbsp;Shamsa Bibi,&nbsp;Aijaz Rasool Chaudhry,&nbsp;Faleh Zafer Alqahtany,&nbsp;Abdullah G. Al-Sehemi,&nbsp;H. Algarni","doi":"10.1007/s11224-026-02728-2","DOIUrl":"10.1007/s11224-026-02728-2","url":null,"abstract":"<div><p>The exploration of triazine derivatives in nonlinear optics (NLO) has gained remarkable momentum in recent years. Their distinctive structural framework, featuring donor-acceptor systems connected by a π-conjugated bridge, has placed them at the forefront of advanced material innovation. We have conducted a theoretical study on two series of triazine-based NLO systems: symmetrical (1 S to 4 S) and asymmetrically substituted (1 A to 4 A) triazine derivatives, employing density functional theory (DFT). Among all the derivatives, 4 A exhibits the highest linear isotropic (α_iso) and anisotropic polarizability (α_aniso) as 104.1 × 10^− 24 esu and 85.65 × 10^− 24 esu, respectively. Furthermore, the asymmetrically substituted 4 A, showcases the largest static third-order NLO polarizability &lt; γ &gt; value of 716.6 × 10^− 36 esu, which is nearly 108 times higher than that of the prototype NLO molecule, <i>para</i>-nitroaniline, calculated under the same theoretical conditions. The solvent dynamics of the compounds indicate that &lt; γ &gt; values increase by ~ 2–3 times, underscoring that the conductor-like screening model (COSMO) tends to inflate the NLO response compared to the gas and implicit solvation phases. The dynamic &lt; γ &gt; value for the top-performing NLO system, 4 A, was computed over a broad spectrum of laser wavelengths (1907 –489 nm). For the EFISHG process, the &lt; γ &gt; is observed to be 565.29 × 10^− 36 esu and 648.27 × 10^− 36 esu at 1907 nm and 1500 nm, respectively. TD-DFT calculations reveal the lowest transition energy of 3.564 eV, significantly enhancing the NLO efficiency of 4 A. The frontier molecular orbitals (FMOs) indicated a decrease in crucial orbital energy gap due to influence of donor-acceptor attached to the triazine core, with values ranging between 6.68 eV-5.38 eV. Our findings suggest that the designed triazine-based NLO systems hold great promise, likely evoking interest among researches in the optoelectronics domain. potentially sparking interest among researchers in the field of optoelectronics.</p></div>","PeriodicalId":780,"journal":{"name":"Structural Chemistry","volume":"37 4","pages":"2095 - 2115"},"PeriodicalIF":2.3,"publicationDate":"2026-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148614735","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":"Restoring immune tolerance in autoimmune hepatitis: therapeutic implications of the 2025 Nobel prize discoveries","authors":"Krisztina Hagymási","doi":"10.1007/s11224-026-02725-5","DOIUrl":"10.1007/s11224-026-02725-5","url":null,"abstract":"<div><p>The Nobel Prize of Physiology or Medicine 2025 was awarded jointly to Mary E. Brunkow, Frederick J. Ramsdell and Shimon Sakaguchi for their discoveries identifying regulatory T cells (Treg) controlling our immune system response to substances from outside and inside the body, maintaining the peripherial immune tolerance. Their discoveries encourage the development of medical treatments for cancer and autoimmune diseases. Author summarizes the immunosuppresive therapy of autoimmun hepatitis, emphasizing the importance of maintained Treg function, rather then a generalized immunsuppression.</p></div>","PeriodicalId":780,"journal":{"name":"Structural Chemistry","volume":"37 2","pages":"1041 - 1044"},"PeriodicalIF":2.2,"publicationDate":"2026-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147388576","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":"Rational design of fluorinated central cores via peripheral acceptor modification: a DFT/TD-DFT exploration for high-performance organic solar cells","authors":"Iqra Shafiq,&nbsp;Sadia Jamal,&nbsp;Shumaiza Kanwal,&nbsp;Khalid Mahmood,&nbsp;Muhammad Imran,&nbsp;Muhammad Nadeem Arshad","doi":"10.1007/s11224-025-02661-w","DOIUrl":"10.1007/s11224-025-02661-w","url":null,"abstract":"<div><p>Currently, the fluorinated core based materials (<b>AQD1</b>–<b>AQD6</b>) with A₁–π–A₂–π–A₁ configuration molecules were desgined by structural modification of peripheral acceptors in <b>AQR</b> reference. Benzothiophene based (BT) acceptors were utilized for the designing of <b>AQD1</b>–<b>AQD6</b> chromophores. The influence of BT acceptors on photovoltaic characteristics of designed chromophores was accomplished by DFT and TD-DFT calculations at M06/6-311G (d, p) level. Incorporating benzothiophene-based acceptors with strong electron-withdrawing groups significantly reduced the energy gaps (2.16–2.34 eV) and red-shifted the absorption maxima (697–745 nm) compared to the reference molecule (ΔE = 2.34 eV, λmax = 691.64 nm). A significant charge was transferred from central core towards terminal acceptors as illustrated by frontier molecular orbitals (FMOs) surfaces, transition density matrix (TDM), and density of states (DOS). Furthermore, the desgined derivatives exhibited appreciable open-circuit voltages (<i>V</i>_<i>oc</i>) when blended with the PTB7 donor, indicating their strong potential as efficient OSC candidates. Among the studied compounds, <b>AQD4</b> exhibited the most promising optoelectronics properties, such as lowest energy gap (2.16 <i>eV</i>), highest bathochromic shift (<i>λ</i>_<i>max</i> = 744.96 nm), and minimal exciton binding energy (0.50 <i>eV</i>) owing to the strong nitro group on BT acceptor. These results highlight that end-capped modification with BT acceptors may enhances the optoelectronic and photovoltaic performance of OSC materials, emphasizing the importance of rational molecular design for efficient device optimization.</p></div>","PeriodicalId":780,"journal":{"name":"Structural Chemistry","volume":"37 5","pages":"2921 - 2943"},"PeriodicalIF":2.3,"publicationDate":"2026-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148950504","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":"Dynamic behaviour of a soft porous crystal based on a tetra-4-(4-methyl-pyridinium) phenylmethane salt","authors":"Danilo Marchetti,&nbsp;Riccardo Testa,&nbsp;Roberta Pinalli,&nbsp;Alessandro Pedrini,&nbsp;Chiara Massera","doi":"10.1007/s11224-026-02722-8","DOIUrl":"10.1007/s11224-026-02722-8","url":null,"abstract":"<div>\u0000 \u0000 <p>A new, soft porous crystal of general formula <b>TMPPM(PF</b>_<b>6</b><b>)</b>_<b>4</b> has been assembled by combining the rigid tetrahedral tecton tetra-4-(4-methyl-pyridinium)phenylmethane (<b>TMPPM</b>^<b>4+</b>) as cationic organic linker and hexafluorophosphate PF₆⁻ as anionic node. By dissolving the solid compound in acetone, the solvated form <b>TMPPM(PF</b>_<b>6</b><b>)</b>_<b>4</b>⋅<b>0.67(Acetone)</b> is obtained, whose open-pore structure (<b><i>op</i></b>-<b>TMPPM(PF</b>_<b>6</b><b>)</b>_<b>4</b>) contains one-dimensional channels of octagonal cross-section where the disorder solvent is accommodated. By heating the crystals, the solvent is released in a single-crystal-to-single-crystal transformation that leads to a closed-pore phase (<b><i>cp</i></b>-<b>TMPPM(PF</b>_<b>6</b><b>)</b>_<b>4</b>) comprising unconnected voids. The reversible, dynamic adsorption-desorption process was followed by <i>ex situ</i> and <i>in situ</i> PXRD analyses, respectively. Moreover, the release of acetone over time was shown to be in good agreement with the guest-packing efficiency rule.</p>\u0000 </div>","PeriodicalId":780,"journal":{"name":"Structural Chemistry","volume":"37 3","pages":"1089 - 1096"},"PeriodicalIF":2.2,"publicationDate":"2026-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11224-026-02722-8.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147938684","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":"Versatile pyrazine derivatives with robust nonlinear optical (NLO) performance: symmetrical design and theoretical exploration","authors":"Shamsa BiBi,&nbsp;Muneeb Ahmad,&nbsp;Shabbir Muhammad,&nbsp;Shafiq urRehman,&nbsp;Bakhet A. Alqurashy,&nbsp;Abdul Qayyum Khan","doi":"10.1007/s11224-026-02720-w","DOIUrl":"10.1007/s11224-026-02720-w","url":null,"abstract":"<div><p>The work uses quantum chemistry to study symmetrically substituted pyrazine-based derivatives <b>Pyr-1</b> to <b>Pyr-8</b> that follow the donor-π-donor (D-π-D) or acceptor-π-acceptor (A-π-A) pattern aimed at better performance in nonlinear optics (NLO). The properties were studied using DFT and TD-DFT methods at the M06-2X/6-311G** level. All these derivatives exhibit high planarity and extended conjugation, validated by low MPP and SDP values, which facilitate charge transfer within the molecule. Using the electrophilicity and nucleophilicity indices, it is found that <b>Pyr-5</b> and <b>Pyr-8</b> are strong nucleophiles, whereas <b>Pyr-1</b> and <b>Pyr-2</b> exhibit a strong electron-accepting tendency. Analysis of the ELF, MEP, and EDD maps confirms that there is efficient delocalization of electrons and current flow within the molecule. DOS and FMO analysis show the HOMO-LUMO gap in <b>Pyr-6</b> and <b>Pyr-8</b> is smaller than that in <b>Pyr-7</b>, allowing for more efficient transfer of electrons. TDM results suggest that highly planar compounds exhibit strong electron-hole correlations and closely spaced transitions. In addition, NBO analysis reveals that, among all the studied compounds, <b>Pyr-1</b> shows the strongest LP → π* and π → π* interactions and is the most energetically stable. This is attributed to its dipyrrolopyrrole moieties and greater conjugation. The third-order hyperpolarizability of <b>Pyr-8</b> is 463.1 × 10^− 36 esu, approximately 64 times greater than that of <i>p</i>-nitroaniline (7.2 × 10^− 36 esu), due to its planar dipyrrolopyrrole termini and extended conjugation. According to TD-DFT, the material’s enhanced NLO behavior is supported by its low excitation energy, strong oscillator strength, and high transition dipole moments. The results from this study offer practical advice for making effective third-order NLO materials for use in optoelectronics.</p></div>","PeriodicalId":780,"journal":{"name":"Structural Chemistry","volume":"37 4","pages":"2117 - 2137"},"PeriodicalIF":2.3,"publicationDate":"2026-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148613641","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":"Correlation between crystal structure and color fading in the solid-state photochromism of viologen derivatives","authors":"Shota Hirai,&nbsp;Akiko Sekine,&nbsp;Hidehiro Uekusa","doi":"10.1007/s11224-026-02723-7","DOIUrl":"10.1007/s11224-026-02723-7","url":null,"abstract":"<div><p>The solid-state photochromism of viologen derivatives offers significant potential for the development of optical and multifunctional materials; however, the structural factors governing their color fading behavior remain poorly understood. In this study, we synthesized and characterized four viologen-based ionic compounds featuring different cationic substituents (H or <i>tert</i>-butyl) and counter anions (Br⁻ or <i>p</i>-toluenesulfonate, TsO⁻) to systematically investigate the correlation between crystal structure and the thermal fading rate of photoinduced color changes. Upon UV irradiation, all compounds exhibited characteristic coloration due to the formation of viologen radical cations, followed by thermal decolorization in the dark. The fading rate was evaluated using time-dependent diffuse reflectance UV-vis spectroscopy. Structural analyses via single-crystal X-ray diffraction revealed that, in bromide salts, shorter donor–acceptor (D–A) distances between the bromide anion and viologen cation corresponded to faster fading rates, consistent with a distance-dependent electron back-transfer mechanism. In contrast, for TsO⁻ salts, one compound exhibited faster fading despite a longer D–A distance. Crystal packing analysis and DFT calculations indicated that this behavior stems from a π–π stacking-mediated electron transfer pathway between the viologen cation and the aromatic TsO⁻ anion. These findings highlight that, while ionic D–A distances dominate in systems with atomic anions, supramolecular interactions such as π–π stacking significantly influence photochromic fading in systems with molecular anions. This work provides new insights into structure–property relationships in solid-state photochromic systems and contributes to the rational design of viologen-based materials with tunable optical responses.</p></div>","PeriodicalId":780,"journal":{"name":"Structural Chemistry","volume":"37 3","pages":"1109 - 1118"},"PeriodicalIF":2.2,"publicationDate":"2026-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11224-026-02723-7.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147938555","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":"Mechanistic insights into (3 + 2) cycloaddition of glutaraldehyde-N-Aryl nitrone with cinnamaldehyde: Electron density, docking, and molecular dynamics analysis","authors":"Raad Nasrullah Salih,&nbsp;Haydar Mohammad-Salim,&nbsp;Muheb Algso","doi":"10.1007/s11224-025-02698-x","DOIUrl":"10.1007/s11224-025-02698-x","url":null,"abstract":"<div><p>This study investigates the [3 + 2] cycloaddition (32CA) reaction between Glutaraldehyde-N-aryl nitrone (<b>GN-1</b>) and Cinnamaldehyde (<b>CA-2</b>) to elucidate its mechanistic pathway and biological relevance. Understanding this reaction is important because it leads to the synthesis of pharmacologically significant isoxazolidine derivatives, compounds with therapeutic potential. Using Density Functional Theory (DFT) within the framework of Molecular Electron Density Theory (MEDT), we explored the potential energy surface (PES) and identified four stereoisomeric routes. The <i>ortho</i>-<i>endo</i> pathway was found to be both thermodynamically (ΔG = − 8.92 kcal.mol⁻¹) and kinetically the most favorable. Global Electron Density Transfer (GEDT) analysis indicated a forward electron density flux (FEDF) of 0.0594 e, confirming a polar mechanism. Electron Localization Function (ELF) and Bonding Evolution Theory (BET) analyses revealed asynchronous bond formation during the transition state. To explore biological potential, molecular docking against the EGFR L858R mutant (PDB ID: 2ITZ) showed that compound <b>IC-6</b> exhibited the strongest binding affinity (–10.19 kcal.mol⁻¹). Molecular dynamics simulations (200 ns) confirmed the stability of the <b>IC-6</b>/EGFR complex, while absorption, distribution, metabolism, excretion, and toxicity (ADMET) predictions indicated favorable pharmacokinetic and drug-likeness properties. Overall, this work provides quantitative mechanistic insight into the electron density reorganization governing the 32CA reaction and highlights the therapeutic potential of the resulting isoxazolidine derivatives. The novelty of this research lies in the integrated MEDT, ELF, molecular dynamics (MD) approach, which advances beyond previous studies by correlating electron density transfer with biological activity and drug behavior.</p></div>","PeriodicalId":780,"journal":{"name":"Structural Chemistry","volume":"37 5","pages":"2895 - 2920"},"PeriodicalIF":2.3,"publicationDate":"2026-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148950440","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":"DFT study on interaction of some pharmaceutical residues with 4-nitrotoluene: a model system for nitro-functionalized material","authors":"Pubalee Sarmah,&nbsp;Asif Mondal,&nbsp;Rajan Kumar,&nbsp;Bapan Saha","doi":"10.1007/s11224-025-02693-2","DOIUrl":"10.1007/s11224-025-02693-2","url":null,"abstract":"<div><p>Pharmaceuticals as emerging contaminants (EC) in water are one of the major challenges for the future. In this context, the reactivity of selective ECs such as ibuprofen, paracetamol, aspirin, metronidazole, and metoprolol, and their interaction with 4-nitrotoluene (4-NT) are discussed in the light of density functional theory (DFT). The analysis highlights the favorable formation of 4-NT–EC complexes with interaction energies within the range of –13.18 to–6.28 kcalmol⁻¹. The complex formation is exothermic and occurs via non-covalent interactions. Effective interaction leads to changes in the energy of molecular orbitals (MOs) and subsequent alterations in global reactivity descriptors. QTAIM and NCI analyses have also suggested the presence of van der Waals forces between 4-NT and ECs. The findings of this work provide a theoretical basis for future studies on wastewater treatment and the adsorption of ECs onto nitro-substituted materials.</p><h3>Graphical Abstract</h3><div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":780,"journal":{"name":"Structural Chemistry","volume":"37 5","pages":"2881 - 2894"},"PeriodicalIF":2.3,"publicationDate":"2026-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148950502","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":"Generalization of localization delocalization matrices to k-tuple electron number and non QTAIM partitions of the charge density","authors":"Bernard Silvi,&nbsp;Mohammad Esmaïl Alikhani","doi":"10.1007/s11224-025-02706-0","DOIUrl":"10.1007/s11224-025-02706-0","url":null,"abstract":"<div><p>This article presents a generalization of the Localization Delocalization Matrices (LDMs) to <i>k</i>-tuple populations over space-filling non-overlapping volumes. It is shown that LDMs are the expectation value of the LDM operator. The expression of this latter is proposed for electron populations and extended to to higher <i>k</i>-tuple electron populations. Electron Distribution Functions enable efficient calculations of LDMs beyond the single determinant approximation and of the non-overlapping constraint. Examples on small molecules are reported to illustrate the possibilities of the method.</p></div>","PeriodicalId":780,"journal":{"name":"Structural Chemistry","volume":"37 4","pages":"1731 - 1737"},"PeriodicalIF":2.3,"publicationDate":"2026-01-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148613446","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 earliest recognition of what is now referred to as a Racemic Mimic crystal, illustrated with two modern examples – the crystalline behavior of (D,L)- and (L)-selenomethionine and (D,L)- and (L)-cysteine. Racemic Mimics Part 7","authors":"Ivan Bernal,&nbsp;Roger A. Lalancette","doi":"10.1007/s11224-025-02644-x","DOIUrl":"10.1007/s11224-025-02644-x","url":null,"abstract":"<div><p>The concept of crystallization by the pathway labelled “Racemic Mimic” is very recent; in fact, the very name was only coined in a brief introduction to the subject in 2021 (vide infra). Therefore, we decided to remedy the problem of communicating these ideas with those unaware of the subject by illustrating its basics with two simple examples obtained from the literature, <i>i.e.</i>, (D,L)- and (L)-selenomethionine and (D,L)- and (L)-cysteine. These structures were very well done, but the original authors were unaware at the time that they constituted examples of these Racemic Mimics. We also give references to more advanced examples for those finding the topic interesting enough to proceed further (vide infra).</p></div>","PeriodicalId":780,"journal":{"name":"Structural Chemistry","volume":"37 2","pages":"701 - 707"},"PeriodicalIF":2.2,"publicationDate":"2026-01-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147388602","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}