{"title":"Rejuvenation mechanism of cross-linked epoxy resin on aged asphalt: insights from molecular dynamics and rheology","authors":"Zhenghong Xu, Zijia Xiong, Minghui Gong, Jiao Jin, Jinxiang Hong, Jinliang Cheng, Lei Jiang","doi":"10.1007/s00894-025-06493-7","DOIUrl":"10.1007/s00894-025-06493-7","url":null,"abstract":"<div><h3>Context</h3><p>Asphalt recycling represents an advanced, eco-friendly pavement rehabilitation technology where proper rejuvenation of aged asphalt ensures the economic viability of reclaimed asphalt pavement (RAP). In this study, molecular models of raw asphalt and aged asphalt were constructed using Materials Studio. The reaction between the epoxy resin and curing agent was automated via a Perl script, establishing molecular dynamics models of epoxy asphalt and epoxy-aged asphalt containing approximately 30% epoxy resin and achieving a cross-linking rate of 87.5%. Through a dual-method approach—directly analyzing cross-linked epoxy resin’s impact on aged asphalt molecules and comparatively evaluating aging degradation in virgin versus epoxy asphalt—we employed cohesive energy density, free volume fraction, and mean square displacement analyses. Results demonstrate that cross-linked epoxy resin weakens strong polar interactions between aged asphalt molecules, increases molecular free volume and diffusion capacity, and significantly inhibits polar molecule aggregation, thereby collectively enhancing aged asphalt performance. Rheological testing confirms that epoxy resin partially restores the viscoelastic properties of aged asphalt, providing macroscopic validation of molecular simulation results. This multi-scale verification advances fundamental understanding of epoxy-recycled asphalt (ERA) systems and establishes theoretical foundations for optimizing pavement performance in sustainable regeneration applications.</p><h3>Methods</h3><p>To investigate the effect of epoxy polymers on the aging behavior of asphalt, molecular models of virgin asphalt, aged asphalt, epoxy asphalt, and epoxy-aged asphalt were constructed using the Amorphous Cells module of the Materials Studio 2020 software. Molecular dynamics simulations of these four asphalt models were then performed using the Forcite module, with atomic and molecular interactions described by the COMPASS II force field.</p></div>","PeriodicalId":651,"journal":{"name":"Journal of Molecular Modeling","volume":"31 10","pages":""},"PeriodicalIF":2.5,"publicationDate":"2025-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145136125","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}
Yingzhe Du, Jun Li, Ning Wen, Zheng Zhang, Dan Song
{"title":"The pyrolysis of polyimide and epoxy resin by the ReaxFF molecular dynamics simulation","authors":"Yingzhe Du, Jun Li, Ning Wen, Zheng Zhang, Dan Song","doi":"10.1007/s00894-025-06492-8","DOIUrl":"10.1007/s00894-025-06492-8","url":null,"abstract":"<div><h3>Context</h3><p>Polyimide (PI) and epoxy resin will age by hot corrosion and long-term high temperature, losing the heat insulting property and forming tremendous potential dangers. In order to evaluate the thermal properties accurately and detect the potential damage of them, the pyrolysis processes of them were studied. The results show that the main products of PI are CO<sub>2</sub> and CN· at high temperature, and their formation are both associated with the break of C-N bond in the imide rings. With the increase of the temperature, the number of CN· increases, but the number of CO<sub>2</sub> decrease. Among several reaction path of the PI productions, the <i>p1</i> is the lowest activation energy and can form CO<sub>2</sub>. The bond dissociation energies of C-N bond in <i>p3</i> and <i>p4</i> are higher than <i>p1</i>. We also investigated the pyrolysis process of the epoxy resin. The results show that the main products of epoxy resin are H<sub>2</sub>, CH<sub>2</sub>O, H<sub>2</sub>O, and CH<sub>4</sub> at 1300 K, and the H<sub>2</sub> is generated by the collision of the hydrogen atoms (<i>p1</i> path), the CH<sub>2</sub>O is generated by the partial decomposition of the C<sub>2</sub> or C<sub>3</sub>, which can form the epoxy groups on the ends of the epoxy resin.</p><h3>Methods</h3><p>Reactive force field (ReaxFF) molecular dynamics simulations were used to study the pyrolysis of PI and epoxy resin. The initial structures of PI and epoxy resin were constructed using Material Studio software, followed by geometry optimization to achieve the most stable configuration. Pyrolysis simulations were performed using the large-scale atomic/molecular massively parallel simulator (LAMMPS). The simulation employed NPT ensemble (0.1 MPa, 298 K) to adjust the system density to 1.0 g/cm<sup>3</sup>, and NVT ensemble for pyrolysis Calculations with a time step of 1 fs and total simulation time of 1 ns. Temperature was controlled using the Bersenden method, with key simulation temperatures including 1300 K (epoxy resin) and 2800–3800 K (PI).</p></div>","PeriodicalId":651,"journal":{"name":"Journal of Molecular Modeling","volume":"31 10","pages":""},"PeriodicalIF":2.5,"publicationDate":"2025-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145136144","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}
Shradheya R. R. Gupta, Rashmi Rameshwari, Indrakant Kumar Singh
{"title":"Discovery of a potent ROR1 inhibitor using μs-scale MD simulations, wt-metadynamics, and absolute binding free energy calculations","authors":"Shradheya R. R. Gupta, Rashmi Rameshwari, Indrakant Kumar Singh","doi":"10.1007/s00894-025-06508-3","DOIUrl":"10.1007/s00894-025-06508-3","url":null,"abstract":"<div><h3>Context</h3><p>Receptor tyrosine kinase-like orphan receptor 1 (ROR1) is a cancer-associated pseudokinase with low expression in normal adult tissues but elevated levels in various malignancies, making it a promising therapeutic target. Among ~ 4 million compounds, CHEMBL3926946 emerged as the most promising candidate, demonstrating a persistent binding pose and a well-defined free energy basin. Well-tempered metadynamics (wt-MetaD) revealed a deep minimum of 26.00 ± 2.44 kcal/mol, indicating a highly stable interaction. CHEMBL3926946 exhibited a favourable Absolute Binding Free Energy Perturbation (ABFEP) of − 16.52 ± 0.37 kcal/mol, significantly outperforming the inhibitor Ponatinib (− 8.67 ± 0.94 kcal/mol), supported by persistent interactions with GLU523 and LEU479. This study highlights CHEMBL3926946 as a robust lead for ROR1-targeted cancer therapy and emphasizes the utility of combining wt-MetaD and ABFEP for reliable hit prioritization.</p><h3>Methods</h3><p>We employed a multilayered in silico pipeline integrating high-throughput virtual screening, long-timescale molecular dynamics (MD), wt-MetaD, and ABFEP. Ligands and protein were prepared using the OPLS2005 force field, and all stages up to wt-MetaD were conducted in Maestro (v12.8.117) using the same force field. A library of ~ 4 million compounds yielded 137 candidates, Further shortlisted via MD. 7 high-confidence molecules underwent 5 independent MD replicates with randomized seeds to ensure statistical robustness. The top 3 compounds were validated by 1 μs (1000 ns) simulations to assess long-term conformational stability and wt-MetaD to reveal deep minimum. ABFEP calculations were performed using the CGenFF force field in NAMD 3.0. We benchmarked ABFEP protocol against experimentally validated ligands, successfully reproducing experimental binding free energies (ΔG), confirming the protocol’s predictive reliability.</p><h3>Graphical Abstract</h3><div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":651,"journal":{"name":"Journal of Molecular Modeling","volume":"31 10","pages":""},"PeriodicalIF":2.5,"publicationDate":"2025-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145136042","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}
Damián Delgado-Montiel, Norma Flores-Holguín, Jesús Baldenebro-López, Rody Soto-Rojo, Manuel Luque-Roman, Tomás Delgado-Montiel, Daniel Glossman-Mitnik
{"title":"Rational design of triphenylamine-based sensitizers for DSSCs: a DFT comparison of pyridine and amine donor substituents","authors":"Damián Delgado-Montiel, Norma Flores-Holguín, Jesús Baldenebro-López, Rody Soto-Rojo, Manuel Luque-Roman, Tomás Delgado-Montiel, Daniel Glossman-Mitnik","doi":"10.1007/s00894-025-06498-2","DOIUrl":"10.1007/s00894-025-06498-2","url":null,"abstract":"<div><h3>Context</h3><p>The rational design of metal-free organic sensitizers is critical for developing cost-effective, high-efficiency dye-sensitized solar cells (DSSCs). This study uses density functional theory (DFT) to explore how modifying the triphenylamine (TPA) donor with pyridine rings or amino groups at ortho-, meta-, and para-positions affects the optoelectronic properties of D-π-A sensitizers. Our calculations show that para-position amino substitution (dye N3) yields the most red-shifted absorption (<span>({lambda }_{max})</span>=523, 50 nm beyond reference dyes), the highest theoretical open-circuit voltage (Voc = 1.77 eV, 0.3 eV higher than others), and enhanced charge transfer efficiency. These findings highlight para-position amines as a promising strategy for optimizing DSSC performance and identify N3 as a prime candidate for synthesis and experimental validation.</p><h3>Methods</h3><p>Ground-state geometries, vibrational frequencies, and frontier molecular orbitals were calculated using the M06 functional with the 6-31G(d) basis set, chosen for its accuracy in organic systems. UV–Vis absorption and excited-state properties were predicted via time-dependent DFT (TD-DFT) with the M06-2X functional, optimized for excited-state accuracy, and the 6-31G(d) basis set. Solvation effects in acetonitrile were modeled using the IEF-PCM polarizable continuum model. Calculations were performed with Gaussian 16.</p></div>","PeriodicalId":651,"journal":{"name":"Journal of Molecular Modeling","volume":"31 10","pages":""},"PeriodicalIF":2.5,"publicationDate":"2025-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145136182","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":"Theoretical investigation on sensing of dopamine and tyramine neurotransmitters by the B9N9 nanoring","authors":"Ascharya Kumar Kar, Swetapadma Praharaj, Tarun Yadav, Somenath Garai, Dileep Kumar Gupta, Dibyaranjan Rout","doi":"10.1007/s00894-025-06478-6","DOIUrl":"10.1007/s00894-025-06478-6","url":null,"abstract":"<div><h3>Purpose</h3><p>The investigation concerns the first demonstration of employing the B<sub>9</sub>N<sub>9</sub> nanoring as an active material for sensing dopamine and tyramine neurotransmitters.</p><h3>Method</h3><p>The calculations for optimization and vibrational frequencies of B<sub>9</sub>N<sub>9</sub> ring, dopamine, and tyramine neurotransmitters have been executed by using density functional theory (DFT) available in the Gaussian09 suite. The standard functional (B3LYP) coupled with the basis set 6-311G(d, p) have been adopted for calculations. Natural bond orbital (NBO) analysis quantified charge transfer, while molecular electrostatic potential (MEP) mapping, electron localization function (ELF), reduced density gradient (RDG) analysis, and quantum theory of atoms in molecules (QTAIM) characterized intermolecular interactions.</p><h3>Results</h3><p>The responsiveness of B<sub>9</sub>N<sub>9</sub> ring towards the considered neurotransmitters is characterized thoroughly by the optimized electronic structures, energies, electronic, and other properties using density functional theory (B3LYP/6-311G(d, p)). The interaction of dopamine and tyramine governs through formation of the N-B dative bond in the most favorable configurations. The interaction energies for the most stable configurations of dopamine@B<sub>9</sub>N<sub>9</sub> and tyramine@B<sub>9</sub>N<sub>9</sub> complexes are found to be −22.11 and −21.49 kcal/mol, respectively, which show a significant interaction of neurotransmitters to nanoring and elucidate the adoption of B<sub>9</sub>N<sub>9</sub> ring in sensing applications for these neurotransmitters. The critical conventional electronic parameters, viz., HOMO, LUMO, Fermi energy, work function, and energy gap, are also computed, and the effect of an aqueous medium is investigated on these parameters. The ELF and RGD techniques are used to quantify the electron density distribution and explore the involved interactions. TD-DFT calculations are performed to simulate the UV-Vis spectra. Additionally, a quantum theory of atoms in molecules (QTAIM) analysis is conducted, which shows that dopamine@B<sub>9</sub>N<sub>9</sub> and tyramine@B<sub>9</sub>N<sub>9</sub> exhibit stronger hydrogen bond interactions, resulting in increased bond strengths.</p><h3>Conclusion</h3><p>B<sub>9</sub>N<sub>9</sub> nanoring shows significant interaction with both neurotransmitters and results in the change in the electronic properties helping in detection of both neurotransmitters.</p><h3>Graphical Abstract</h3><div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":651,"journal":{"name":"Journal of Molecular Modeling","volume":"31 10","pages":""},"PeriodicalIF":2.5,"publicationDate":"2025-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145136101","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":"Interactions of imidazole with water molecules","authors":"Alhadji Malloum, Jeanet Conradie","doi":"10.1007/s00894-025-06515-4","DOIUrl":"10.1007/s00894-025-06515-4","url":null,"abstract":"<div><h3>Context</h3><p>Understanding the interactions of imidazole and water molecules is essential for several chemical and biological activities. Literature mining shows that investigations of hydrated imidazole are rare. In this work, interactions between imidazole and explicit water molecules are investigated. The structures of the complexes formed by imidazole and water molecules are used to estimate imidazole’s hydration enthalpy and free energy. QTAIM investigation shows that imidazole accepts two strong hydrogen bondings while donating one. In addition, it also interacts with water molecules through weaker bonding interactions. The results reported in this work reproduce previous experimental observations and molecular dynamics simulations.</p><h3>Methods</h3><p>The investigation started by generating initial configurations through global optimizations using classical potential energy. Then, a suitable functional of density functional theory (DFT) is selected between 20 functionals, including dispersion corrections, by benchmarking to the DLPNO-CCSD(T1)/CBS. The M06L-D3 functional is found to be the most accurate. The structures of the imidazole-water clusters, <span>(text {IMZ}(text {H}_2text {O})_n)</span>, <span>(n=1-12,;64)</span>, are then optimized at the M06L-D3/def2-TZVPP level of theory. Hydration free energy and enthalpy are estimated using the cluster continuum solvation model. Calculations are performed using Gaussian 16 and ORCA suite of programs. Quantum theory of atoms in molecules (QTAIM) is performed using the AIMAll program.</p></div>","PeriodicalId":651,"journal":{"name":"Journal of Molecular Modeling","volume":"31 10","pages":""},"PeriodicalIF":2.5,"publicationDate":"2025-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00894-025-06515-4.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145136131","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":"Investigate the potential inhibitors of sphingosine kinase 1 (SphK1) with molecular dynamics and artificial intelligence drug design methods","authors":"Yahui Zhang, Yiru Wang, Junfeng Wan, Mengxia Zhao, Qingjie Zhao, Huiyu Li, Yuanming Cao","doi":"10.1007/s00894-025-06503-8","DOIUrl":"10.1007/s00894-025-06503-8","url":null,"abstract":"<div><h3>Context</h3><p>Sphingosine kinase 1 (SphK1) is a sphingosine kinase that can catalyze the phosphorylation of sphingosine to generate sphingosine-1-phosphate. The J-type channel of SPHK1 plays an important role in processes such as cell signaling. Therefore, this study aims to investigate the interaction mechanism between Epidanshenspiroketallactone, PF-543, and SPHK1 in the J-type channel, and to design new small molecules using AI Drug Design (AIDD). Molecular dynamics (MD) simulations reveal that hydrophobic interactions and π-π stacking are of critical significance in stabilizing the J-channel conformation of Sphk1. With MD and AIDD methods, our research provides a novel potential approach for the exploration and design of SphK1 inhibitors.</p><h3>Methods</h3><p>The binding mechanism of Epidanshenspiroketallactone and PF-543 with SphK1 was predicted by the molecular dynamics (MD) method using Gromacs-2022–2. Molecular docking was carried out with MolAICal, and the structures were visualized with the Pymol software. The MD simulation force field was selected as the AMBER99SB force field, the temperature was set at 310 K, and the total MD simulation time was 7.2 μs. A recurrent neural network-long short-term memory (RNN-LSTM) machine model was employed for the design of novel inhibitors.</p></div>","PeriodicalId":651,"journal":{"name":"Journal of Molecular Modeling","volume":"31 10","pages":""},"PeriodicalIF":2.5,"publicationDate":"2025-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145136164","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}
Fei-Yu Chang, Mi Zhong, Zheng-Tang Liu, Qi-Jun Liu
{"title":"Density functional theory study of Mg3TeO6 with excellent optical properties and p-type performance","authors":"Fei-Yu Chang, Mi Zhong, Zheng-Tang Liu, Qi-Jun Liu","doi":"10.1007/s00894-025-06506-5","DOIUrl":"10.1007/s00894-025-06506-5","url":null,"abstract":"<div><h3>Context</h3><p>Due to the limitations of existing p-type transparent conductive oxides (TCOs), this study aims to identify alternative p-type TCO materials with improved performance through first-principles calculations. The electronic, optical, and transport properties of Mg<sub>3</sub>TeO<sub>6</sub> were systematically investigated. Calculations show that Mg<sub>3</sub>TeO<sub>6</sub> is a TCOs with a wide bandgap and good visible light transmittance at different thicknesses, indicating its potential applications in the field of transparent materials. The transport properties of Mg<sub>3</sub>TeO<sub>6</sub> at room temperature were calculated, and it was found that the p-type conductivity of Mg<sub>3</sub>TeO<sub>6</sub> can reach 6.95 S cm<sup>−1</sup>. It has certain comparability with some reported theoretical values of p-type TCO. These results suggest that Mg<sub>3</sub>TeO<sub>6</sub> is a promising candidate for transparent electronics, although further experimental validation is required.</p><h3>Method</h3><p>First-principles calculations based on density functional theory and density functional perturbation theory were employed to execute all calculations in this work. The structural properties were optimized using GGA-PBE functionals, while HSE06 mixed functionals were used for accurate prediction of electronic band structures.</p></div>","PeriodicalId":651,"journal":{"name":"Journal of Molecular Modeling","volume":"31 10","pages":""},"PeriodicalIF":2.5,"publicationDate":"2025-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145110660","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}
Hongbing Shi, Shengping Yu, Fuming Chen, Minzhang Li
{"title":"DFT study on Pt-decorated (9,0) single-walled carbon nanotubes: hydrogen adsorption and sensing","authors":"Hongbing Shi, Shengping Yu, Fuming Chen, Minzhang Li","doi":"10.1007/s00894-025-06499-1","DOIUrl":"10.1007/s00894-025-06499-1","url":null,"abstract":"<div><h3>Context</h3><p>Carbon nanotubes are commonly used for hydrogen detection. However, pure carbon nanotubes exhibit limitations in this application. The Pt-decorated carbon nanotubes are considered to have the potential of hydrogen adsorption and sensing. The adsorption of H<sub>2</sub> on the outside wall of (9,0) single-walled carbon nanotubes (SWCNT(9,0)) were studied using density functional theory (DFT) calculations. The tiny adsorption energy (0.023 eV) implied a high barrier of the adsorption of H<sub>2</sub> on the outer wall of pure SWCNT, so metal atom (Pt, Fe, Ni) was used to decorate SWCNT. The result showed that Pt-SWCNT(9,0) exhibited the highest hydrogen adsorption capacity (0.791 eV) and meanwhile as the most stable catalyst structure. The hydrogen molecule underwent adsorption and dissociation on all three systems. Furthermore, the electronic structures of Pt-SWCNT(9,0) and H<sub>2</sub>/Pt-SWCNT(9,0) were discussed. It is interesting that the interaction between Pt atom and SWCNT(9,0) changed the electronic state of carbon nanotubes and enhanced the adsorption energy of H<sub>2</sub>. In the configurations involving multiple H<sub>2</sub> molecules, most molecules exhibited physical adsorption on Pt-SWCNT(9,0), whereas only one molecule was chemical adsorption. The electron transfer of Pt was promoted with the enhancement of orbital hybridization. In addition, the HOMO–LUMO gap (<i>E</i><sub>g</sub>) increased and the conductivity (<i>σ</i>) of Pt-SWCNT(9,0) changed after the adsorption of H<sub>2</sub>, which was according with the experimental studies. Our calculations reveal that Pt-decorated SWCNT(9,0) has the capabilities of hydrogen adsorption and sensing. In the future, the design of the material structure will tune the conductivity for better H₂ sensor.</p><h3>Methods</h3><p>All DFT calculations were performed using the Gaussian 16 software. GaussView 6.0 software was utilized to visualize the molecular models, molecular orbitals, and electrostatic potential (ESP) of all relevant species. Multiwfn 3.8 software was utilized to plot localized orbital locator (LOL) graph and electron localization function (ELF) distribution maps. The DFT method was the B3LYP-D3BJ. The 6-31G(d,p) basis set was utilized for the C, H atoms, and Lanl2dz basis set for the Pt, Fe, and Ni atoms. No extraneous computational parameters were used in the structure optimization and frequency calculation that could affect calculation accuracy in the gas phase.</p></div>","PeriodicalId":651,"journal":{"name":"Journal of Molecular Modeling","volume":"31 10","pages":""},"PeriodicalIF":2.5,"publicationDate":"2025-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145110658","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}
João P. C. Oliveira, Murillo H. Queiroz, Patricio F. Provasi, Roberto Rivelino
{"title":"A nuclear chemical descriptor based on NMR databases for molecular information: characterization of π-conjugated oligomers","authors":"João P. C. Oliveira, Murillo H. Queiroz, Patricio F. Provasi, Roberto Rivelino","doi":"10.1007/s00894-025-06495-5","DOIUrl":"10.1007/s00894-025-06495-5","url":null,"abstract":"<div><h3>Context</h3><p>Structure–property relationships of increasing systems, such as conjugated oligomers, atomic chains, and H-bonding networks, constitute a problem involving multiple variables in quantum chemical studies. Defining a single parameter that allows investigating different properties of these systems (or even those belonging to a specific chemical group) is not always a simple task. Thus, it is difficult to rationalize the evolution of molecular properties of increasing molecular systems, assigning relevant physicochemical information correlated to their size and structure. For conjugated oligomers, we have proposed a nuclear magnetic resonance (NMR)–based descriptor from the fluctuations of indirect spin–spin coupling constants (SSCCs) between two adjacent <sup>13</sup>C nuclei (<sup>1</sup><i>J</i><sub>CC</sub>) in the π-conjugated system. This parameter is called <i>J</i>-coupling alternation (JCA) and systematically gathers information from structural and electronic properties, allowing a rational evaluation of the molecular properties of growing oligomers. We employ JCA to obtain correlations with vibrational, electronic, and optical properties of conjugated oligomers, belonging to the groups of polypyrrole (PPy), polyfuran (PFu), polythiophene (PTh), and polyselenophene (PSe). This analysis yields excellent linear structure–property relationships, confirming the ability of JCA to characterize realistically different families of π-conjugated oligomers and providing a reliable parameter to design efficient molecular materials.</p><h3>Methods</h3><p>All the oligomers, PPy(<i>n</i>), PFu(<i>n</i>), PTh(<i>n</i>), and PSe(<i>n</i>), with <i>n</i> = 2, 3, 5, 7, 9, and 11, respectively, were fully optimized, without symmetry constraints, using density–functional theory (DFT) at the PBE0/6–311 + G(d,p) level. Next, the vibrational properties were computed within harmonic approximation and NMR spin–spin coupling constants using the GIAO method. Finally, optical properties were obtained via TD-DFT with the CAM-B3LYP/6–311 + G(d,p) method.</p></div>","PeriodicalId":651,"journal":{"name":"Journal of Molecular Modeling","volume":"31 10","pages":""},"PeriodicalIF":2.5,"publicationDate":"2025-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145110659","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}