Search Results (343)

Developing high-performance n-type polymer semiconductors is hindered by the scarcity of strong electron-deficient building blocks. Herein, we report a dual-functionalization strategy that integrates both quinoid and cyano groups into polythiophene backbones to construct n-type polymers. Two new polymers, PQTTCN and PQTVTCN, were synthesized via the Stille copolymerization of a thienoquinoid-based dibrominated monomer (TTD2T-Br) with cyano-functionalized bithiophene and thienylene-vinylene-thienylene distannyl monomers, respectively. Electrochemical and computational analyses confirm that both polymers exhibit low-lying LUMO levels of −4.07 eV and highly planar backbones. In organic field-effect transistors, PQTTCN and PQTVTCN show unipolar n-type charge transport, with electron mobilities of 0.036 and 0.002 cm² V⁻¹ s⁻¹, respectively, which are attributed to their deep frontier molecular orbitals and planar conformations. Upon doping, both polymers exhibit n-type thermoelectric performance, achieving an electrical conductivity and power factor values of 0.16 S cm⁻¹ and 0.75 μW m⁻¹ K⁻² for PQTTCN and 0.043 S cm⁻¹ and 0.17 μW m⁻¹ K⁻² for PQTVTCN, respectively. AFM and GIWAXS results demonstrate that PQTTCN has better dopant compatibility and higher crystallinity than PQTVTCN. This work highlights that the combination of quinoid and cyano units offers a promising strategy for developing high-performance n-type polymer semiconductors for organic electronics. Full article

Organic semiconductors offer a potential class of materials for organic photovoltaic (OPV) applications due to their tunable optoelectronic properties and low-cost processing. A methodical DFT/TD-DFT study of a library of organic donor–π–acceptor (D–π–A) compounds based on triphenylamine donors, thiophene-based π-bridges, and benzothiadiazole/malononitrile acceptors is presented in this work, with the goal of rationalizing the structure–property relationships governing their photovoltaic behavior. CAM-B3LYP calculations were used to analyze the role of donor, bridge, and acceptor units in modulating frontier-orbital alignment, charge-transfer character, and optical absorption properties, as well as to evaluate the active-layer thickness in the estimation of the light-harvesting efficiency. The results, which are intended as internal comparative descriptors rather than predictive device efficiencies, reveal that the most pronounced bathochromic shifts and most favorable optical responses are not simply associated with the strongest donor or acceptor moieties, but rather arise from an optimal balance between frontier-orbital delocalization and charge-transfer character across the molecular framework. A preliminary assessment of photovoltaic descriptors suggests that the proposed computational workflow may provide useful guidelines for the descriptor-guided design and screening of next-generation organic photovoltaic materials. Full article

Phenolic acids exhibit structure-dependent vibrational responses governed by aromatic substitution, π-conjugation, oxygenated functional groups, and molecular environment. In this work, p-coumaric, caffeic, trans-ferulic, and gallic acids were investigated through an integrated experimental Raman, density functional theory (DFT), and chemometric approach to establish molecular relationships between hydroxylation, methoxylation, conjugation, and Raman spectral behavior. Raman spectra were recorded in the solid state and in an ethanol/water (1:1, v/v) mixture. At the same time, DFT calculations were used to optimize the molecular structures, simulate Raman spectra, assign vibrational modes, and evaluate molecular electrostatic potential, frontier orbitals, electronic descriptors, and localized orbital locator maps. The solid-state Raman spectra provided the most resolved molecular fingerprints, with hydroxycinnamic acids exhibiting intense bands corresponding to aromatic and conjugated ν(C=C) modes. In contrast, gallic acid displayed a distinct hydroxybenzoic vibrational pattern dominated by phenolic C–O/O–H and carboxylic contributions. DFT-assisted assignments confirmed that the main spectral differences arise from coupled vibrations involving ν(C=C), ν(C=O), ν(C–O), δ(O–H), aromatic ring deformations, and methoxy-related modes. Molecular electrostatic potential (MEP) and localized orbital locator (LOL) analyses showed that oxygen-centered regions are the most electrostatically and electronically localized sites, thereby explaining the sensitivity of C–O, O–H, and C=O bands to solvent-mediated interactions. HOMO–LUMO analysis revealed extended frontier-orbital delocalization in hydroxycinnamic acids, in contrast to the more localized hydroxybenzoic electronic structure of gallic acid. Principal component analysis confirmed that solid-state Raman spectra provide stronger chemometric discrimination than solution spectra, with PC1 and PC2 explaining 79.0% of the total variance in the solid-state dataset. Overall, the results show that specific functional groups define the principal vibrational domains of the studied phenolic acids. In contrast, the exact band positions, relative intensities, and coupling patterns are additionally modulated by aromatic substitution, π-conjugation, electronic distribution, physical state, and molecular environment. Within the limitations of a single-conformer isolated-molecule model, the combined Raman–DFT–chemometric approach provides a comparative interpretation of the vibrational fingerprints of the four selected compounds. Full article

Contact electrification (CE), also referred to as triboelectrification, describes electron transfer occurring at the interface of dissimilar materials. Its microscopic mechanism remains unclarified due to the complex coupling of multiple physical fields, yet the rapid development of triboelectric nanogenerators (TENGs) has rendered CE a prominent research hotspot in tribology on account of its promising application prospects. Metal/polymer combinations have been widely employed for CE research due to their significant differences in electron gain and loss. Nevertheless, most existing studies focus solely on saturated polymers, and systematic comparative analyses between saturated and unsaturated molecular structures are rarely reported. Accordingly, the intrinsic microscopic origin of enhanced interfacial electrification performance induced by unsaturated groups has not been fully understood. In this work, first-principles calculations based on density functional theory (DFT) are implemented to establish interfacial models consisting of an Al substrate and three types of PTFE single chains: fully saturated-PTFE, PTFE with unsaturated bonds at the chain terminus, and PTFE with unsaturated bonds in the middle of the chain. The inherent mechanism governing the modulation of CE behaviors by unsaturated structures are comprehensively revealed from multiple perspectives, including charge transfer, electrostatic potential, and frontier orbital distribution. Computational results demonstrate that unsaturated groups drastically elevate local electrostatic potential and strengthen the electron-trapping capability of molecular chains, thereby substantially boosting CE performance. Moreover, this modulation effect exhibits remarkable position dependence, where unsaturated structures located in the middle of molecular chains deliver better performance improvement than terminal unsaturated moieties. The electron-donating and electron-accepting properties of materials are dominated by the energy level characteristics of the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO), respectively. This study elucidates the microscopic mechanism of CE at unsaturated polymer/metal interfaces at the molecular scale, and provides theoretical support for optimizing the output performance of TENGs through surface modification strategies. Full article

Developing sustainable lithium-ion batteries (LIBs) requires binder–carbon interfaces that combine mechanical compatibility, interfacial cohesion, and reduced environmental impact. In this work, density functional theory calculations were used to evaluate the interactions of representative binder monomers acrylonitrile (AN), pyrrole (PY), vinylidene fluoride (VDF), and tetrafluoroethylene (TFE) with pristine graphene and chitosan-functionalized graphene oxide (GO/chitosan). Structural, energetic, electronic, and topological features were analyzed using counterpoise-corrected interaction energies, frontier-orbital descriptors, molecular electrostatic potential maps, projected density of states, noncovalent interaction analysis, and quantum theory of atoms in molecules topology. Final interaction energies were obtained at the M06-2X/def2-TZVP level with Boys–Bernardi counterpoise correction to provide a more robust description of weak noncovalent adsorption. Most binder–surface interactions fall within a weak, near-thermoneutral adsorption regime. On pristine graphene, AN and PY exhibit weakly favorable adsorption, with minimum counterpoise-corrected interaction energies of −3.13 and −2.10 kcal mol⁻¹, respectively, whereas TFE and VDF show orientation-dependent, near-neutral behavior. GO/chitosan introduces oxygen-containing and amino functionalities that modify the adsorption balance, particularly for selected perpendicular configurations of fluorinated monomers, although the net stabilization remains modest. NCI, QTAIM, MEP, and PDOS analyses indicate that surface functionalization increases the chemical heterogeneity and directionality of local contacts; however, these local descriptors do not necessarily translate into strong global adsorption energies. Overall, the results identify GO/chitosan as a chemically tunable interface for binder–carbon compatibility in LIB electrodes and demonstrate the importance of triple-ζ, counterpoise-corrected calculations for evaluating weak binder–surface interactions. Full article

A 9-methylacridinium salt, 10-(3,5-di-tert-butylphenyl)-9-methylacridin-10-ium tetrafluoroborate (2), was synthesized from the corresponding acridone by treatment with methylmagnesium bromide followed by tetrafluoroboric acid. Compound 2 was obtained as a yellow solid in 95% yield and characterized by NMR spectroscopy and high-resolution mass spectrometry. Electrochemical measurements revealed irreversible reduction behavior, with a reduction potential of −0.52 V vs. SCE determined by second-harmonic alternating-current voltammetry. Compound 2 exhibited absorption extending into the visible region and fluorescence at 492 nm with a lifetime of 4.6 ns. Unlike the previously reported 9-mesityl analogue, compound 2 was fluorescent, a difference that may reflect the absence of the high-lying donor orbital associated with the 9-mesityl group. Its singlet excited-state reduction potential was estimated to be +2.21 V vs. SCE, indicating substantial photooxidizing ability. DFT and TD-DFT calculations provided complementary insight into its frontier molecular orbital distributions and principal electronic transitions. These findings highlight the influence of the 9-substituent on the electronic and emissive properties of acridinium-based photoactive molecules. Full article

The development of multi-targeted therapeutic agents is increasingly recognized as essential for treating multifactorial diseases. Butyrolactone I and butyrolactone III, γ-butyrolactone derivatives isolated from the marine fungus Aspergillus terreus, represent structurally related natural products with largely unexplored polypharmacological potential. This study employed a comprehensive in silico approach combining ADMET profiling, quantum chemical calculations, molecular docking, and molecular dynamics simulations to evaluate their therapeutic potential across multiple pharmacological targets. Physicochemical analysis revealed favorable drug-like properties for both compounds, with complete compliance with Lipinski’s Rule of Five, high predicted gastrointestinal absorption (>80%), and acceptable toxicity profiles (toxicity class 4, LD₅₀ = 2000 mg/kg). Neither compound showed hepatotoxic, neurotoxic, cardiotoxic, carcinogenic, or mutagenic liabilities. Frontier molecular orbital analysis (DFT/B3LYP/6-31G(d,p)) revealed comparable HOMO energies (−6.054 and −6.059 eV), with butyrolactone III exhibiting enhanced kinetic stability based on a larger HOMO–LUMO gap (4.662 eV vs. 4.443 eV) and higher chemical hardness (η = 2.331 eV vs. 2.222 eV). Molecular docking against four therapeutic targets revealed target-selective binding profiles: butyrolactone III demonstrated binding affinity toward acetylcholinesterase exceeding donepezil (−9.0 vs. −8.3 kcal/mol), while butyrolactone I exhibited MDM2 binding affinity slightly exceeding nutlin-3a (−7.8 kcal/mol). Both compounds showed moderate interactions with COX-2 and topoisomerase IV. Molecular dynamics simulations validated the stability of AChE complexes (RMSD < 2.0 Å) and the MDM2–butyrolactone I complex (RMSD: 0.69 ± 0.09 Å), while the MDM2–butyrolactone III complex exhibited significant instability (RMSD up to 3.55 Å), highlighting the critical role of the prenyl group in MDM2 recognition. These findings, consistent with, though not a direct experimental validation of, previously published in vitro data, support the evaluation of butyrolactone III as a scaffold for neuroprotective agents and butyrolactone I as a p53 pathway modulator for cancer therapy, illustrating the potential value of fungal metabolites in multi-target drug discovery and the role of integrated computational approaches in prioritizing candidates for subsequent experimental testing. Full article

Removing mercury (Hg²⁺) from aqueous environments remains a major environmental challenge due to its high toxicity and bioaccumulation. Graphene quantum dots (GQDs) are adsorbents that show promise in removing these contaminants, but their yield is low in their pristine form. This study investigates the effect of phosphorus (P) doping on vacancy-containing GQDs to enhance Hg²⁺ absorption using density functional theory (DFT) calculations. These were performed at the M06-2X/def2-TZVP level of theory to optimize the structures of GQDs, 1P-GQDs, and 2P-GQDs to evaluate adsorption energies, frontier molecular orbitals, and dipole moments. The results show that GQDs with vacancy have an adsorption energy of −65.21 kcal mol⁻¹, which increases to −104.54 kcal mol⁻¹ for 1P-GQDs, indicating the strongest Hg²⁺ binding. However, 2P-GQD shows a lower value of −73.47 kcal mol⁻¹, suggesting lower efficiency due to electronic competition between dopants. Dipole moments increase from 0.8192 D (GQD) to 4.6729 D (1P-GQD) and 5.7557 D (2P-GQD), confirming strong polarization induced by P incorporation. The HOMO-LUMO gap decreases from 2.204 eV to 1.937 eV after single doping. At the same time, after Hg²⁺ adsorption, the values increase to 5.153 eV (GQD), 3.462 eV (1P-GQD), and 2.068 eV (2P-GQD), indicating configuration-dependent electronic stabilization. PDOS analysis confirms weak cation-π interaction in GQD and strong orbital hybridization in 1P-GQD, consistent with a coordination-type bond. Doping a single phosphate atom optimizes the electronic structure of GQDs with a vacancy site, thereby improving charge transfer and adsorption strength through electronic balance. Full article

CO₂ methanation with renewable hydrogen is a promising strategy for carbon valorization and synthetic natural gas (SNG) production. However, the molecular mechanisms behind catalyst-dependent adsorption and mass transport in zeolite-confined spaces are still not fully elucidated. Herein, we performed comparative molecular simulations on HZSM-5, Ni/ZSM-5 and Ru/ZSM-5 by combining density functional theory (DFT), grand canonical Monte Carlo (GCMC) and molecular dynamics (MD) methods, aiming to clarify the thermodynamic and mass transport mechanisms of reactant enrichment and product desorption in CO₂ methanation. The electronic structures of the three systems were systematically evaluated via Mulliken charge analysis, differential charge density mapping, and frontier molecular orbital calculations. We further quantified the adsorption thermodynamics and diffusion kinetics of reactants and products, focusing specifically on the effects of temperature and framework Si/Al ratio for Ni/ZSM-5. The results show that Ni doping greatly modulates the local electronic environment of the ZSM-5 framework, enhancing the adsorption of CO₂ (−121.9 kJ·mol⁻¹) and H₂ (−81.6 kJ·mol⁻¹) and weakening the adsorption of CH₄ and H₂O. A higher Si/Al ratio reduces CO₂ adsorption capacity, while elevated temperatures inhibit reactant adsorption and lower the diffusion selectivity of CH₄. This demonstrates that moderately low temperatures and moderate Si/Al ratios can optimize the adsorption and diffusion behaviors of reactants and products. This work provides molecular-level insights into the adsorption and diffusion behaviors of Ni/ZSM-5 and offers theoretical references for the rational development of high-performance CO₂ methanation catalysts. Full article

The relationship between the position of the thiazole-5H proton signal and the presence of various substituents in the molecule was investigated in detail from an experimental and theoretical point of view. For this purpose, twenty 2,4-disubstituted thiazole derivatives were carefully chosen and synthesized, and their NMR spectra were recorded. Density functional theory calculations of ¹H NMR chemical shifts, frontier molecular orbitals, and molecular electrostatic potential surfaces were performed. The position of the thiazole-5H proton signal in the NMR spectrum is shown to strongly depend on the type and position of substituents in the molecule. Based on the obtained results, we can conclude that compounds with the smallest values of thiazole-5H proton shift are simultaneously those with small electron affinity, ionization potential and molecular electronegativity values, while compounds with the largest values of thiazole-5H proton shift have large electron affinity, ionization potential, and molecular electronegativity and a small HOMO-LUMO energy gap. These relationships become less clear in the case of compounds with intermediate values of the proton shift. Present research is a step towards an easy-to-use tool for predicting electronic effects in materials containing thiazole, based on the position of the thiazole-5H proton NMR signal. Full article

A novel water treatment agent, ethylenediamine–benzenesulfonic acid-modified polyaspartic acid (PASP-S), was controllably synthesized using an amino ring-opening reaction. The controllable synthesis methods, conditions for polymerization degree, and the molecular weight of the new polymer were explored. The structure was characterized using Fourier-transform infrared spectroscopy (FT-IR), ¹H nuclear magnetic resonance (¹H-NMR), and gel permeation chromatography (GPC). The scale inhibition, corrosion inhibition, and fluorescence properties of the new polymer, as well as the corresponding mechanisms, were investigated using static scale inhibition tests, electrochemical measurements, X-ray photoelectron spectroscopy (XPS), density functional theory (DFT), and frontier molecular orbital (FMO) theory. The results indicate that PASP-S exhibits strong Ca²⁺ chelation ability and can effectively inhibit CaCO₃ and CaSO₄ scaling. At 50 mg/L, the scale inhibition efficiency for Ca₃(PO₄)₂ reaches 99.50%. At 30 mg/L, its corrosion inhibition efficiency is 33.19% higher than that of PASP. Unexpectedly, the polymer shows remarkable selective antibacterial activity. At 100 mg/mL, the inhibition rate against Escherichia coli (E. coli) is 71%, while no obvious inhibition is observed for Bacillus cereus. A good linear relationship is found between fluorescence intensity and concentration. Mechanistic studies demonstrate that PASP-S adsorbs on the scale surface, suppressing crystal growth and distorting crystal morphology. Meanwhile, it forms a protective film on the electrode surface, thus reducing the dissolution and corrosion of carbon steel. Full article

This study aims to elucidate the impact of biostimulants and fungicides on onion yield and quality, utilizing a combined experimental and molecular modeling approach. The biostimulants (Humiblack^®, Agasi^®, and Tifi^®) and fungicides (mancozeb and metalaxyl) were applied to onion crops, resulting in significant improvements in onion quality and yield. The stability and environmental impact of mancozeb and metalaxyl alone and in conjunction with biostimulants were investigated. The stability of the fungicide mixture was assessed in ultrapure water and rainwater, revealing high resistance to hydrolysis. Solar stability assessments, conducted using a sun simulator to mimic environmental conditions, highlighted differences in stability between mancozeb and metalaxyl in the presence of biostimulants. Metalaxyl showed higher photostability owing to the benzene ring. It was also less susceptible to biostimulant effects and remained stable in solution. Density functional theory descriptors and frontier orbital analysis rationalized the higher photoreactivity of mancozeb (smaller HOMO–LUMO gap and broader orbital delocalization). At the same time, molecular dynamics simulations supported stronger solvation of mancozeb and short-range water structuring, consistent with enhanced aqueous susceptibility. The results link fungicide physicochemical properties with field performance and aqueous stability, supporting the use of the fungicide mixture together with a single biostimulant as a practical approach for balancing crop productivity and environmental persistence. Full article

We performed a theoretical analysis (the PBE-D2/DNP level of the density functional theory with the use of the DSPP pseudopotentials) of the geometries, bonding and frontier orbital energies, spin and charge distribution for the entire series (from La to Lu) of lanthanide atoms interacting with I_h−C₈₀ cage, for both η⁵ and η⁶ exohedral coordination patterns. In certain regards, the exohedral η⁵ and η⁶ coordination of Ln atoms to the C₈₀ fullerene cage exhibits similar qualitative and semi-quantitative trends (the bonding strength, shortest Ln^…C distances, charge and spin of lanthanide atoms). The most interesting aspect is the molecular spin of the complexes, where we observed different patterns of ferromagnetic and antiferromagnetic coupling. Three complexes represent an extreme, when the antiferromagnetic coupling results in zero or close-to-zero molecular spin. In some cases, the molecular spin is a simple sum of 2 e of the isolated C₈₀ cage and the spin of an isolated Ln atom. However, the most common situation is when another 2 e spin adds: it is best illustrated with Eu (spin of 7 e for the atomic ground state), where the molecular spin of its η⁵ and η⁶ complexes is not about 9 e but reaches almost 11 e. Full article

Combining plant-derived bioactives could produce effective anti-inflammatory interventions for myofascial inflammation. This study evaluated in vitro synergy and computational mechanisms of curcumin–evodiamine activity against TNF-α, IL-1β, iNOS and COX-2, with frontier molecular orbital analysis to inform putative mechanisms. Evodiamine and curcumin were identified/quantified by HPLC–PDA and LC–MS (λmax 226 nm and 426 nm; RT 8.61 and 9.53 min; [M−H]⁻m/z 302.2 and 367.2). Purities were 98.08 ± 1.92% and 98.04 ± 1.86%. Noncytotoxic concentrations in RAW264.7 cells were determined, then LPS-stimulated cells were treated with evodiamine (0.01 µM), curcumin (0.01 µM) and a 1:1 mixture (0.001 µM). Molecular docking against TNF-α, IL-1β, iNOS and COX-2 and HOMO–LUMO calculations were performed. Curcumin and the combination significantly reduced TNF-α and NO; curcumin and the combination reduced IL-1β, whereas evodiamine alone showed limited effects. Docking predicted stronger binding for curcumin and evodiamine than ibuprofen across targets (e.g., curcumin ΔG −10.18 kcal·mol⁻¹ for TNF-α; evodiamine ΔG −10.02 kcal·mol⁻¹ for COX-2). Frontier orbital energies indicated differing electronic profiles (ibuprofen ΔE 8.62 eV; evodiamine 9.65 eV; curcumin 9.89 eV), suggesting complementary reactivity. The curcumin–evodiamine combination exhibits in vitro anti-inflammatory activity with supportive docking and orbital data, providing mechanistic rationale for further development. Full article

Alzheimer’s disease (AD) is a multifactorial neurodegenerative disorder characterized by cholinergic dysfunction, amyloid-β aggregation, mitochondrial stress, and aberrant kinase activity. Carotenoids, naturally occurring pigments with antioxidant and neuroprotective properties, have emerged as promising candidates for AD intervention. In this study, we performed a systematic stepwise computational screening of a large carotenoid library (n = 1191) to identify multitarget candidates against AD–related proteins. The workflow consisted of predefined ADMET filtering (oral absorption > 90%, Caco-2 > 0.9, logBB > −1, and absence of major CYP inhibition and toxicity alerts), reducing the dataset to 61 compounds, followed by multi-target molecular docking against AChE, BChE, BACE-1, MAO-B, and GSK3-β. Compounds were ranked using an aggregated mean docking score across all five targets, and the top-performing candidate was subjected to detailed mechanistic analyses. Hopkinsiaxanthin emerged as the highest-ranked multitarget carotenoid and was further evaluated using frontier molecular orbital (FMO) analysis, pharmacophore modeling, 100 ns molecular dynamics (MD) simulations, MM/PBSA binding free energy calculations, and per-residue decomposition. Docking predicted favorable estimated binding affinities toward all targets. MD simulations confirmed stable receptor–ligand complexes with low RMSD values (0.278–0.285 nm). MM/PBSA analysis indicated favorable binding free energies, particularly for GSK3-β (−22.73 kcal/mol) and AChE (−21.50 kcal/mol). Per-residue decomposition identified key hotspot residues driving stabilization. Overall, this structured computational framework identifies Hopkinsiaxanthin as a promising multitarget scaffold and supports its prioritization for experimental validation in AD models. Full article