Chemistry and Materials Science

Abstract: Large language models (LLMs) have recently acquired multimodal capabilities that enable them to generate chemical images in addition to text, yet the accuracy of these visual representations remains poorly understood. This study evaluated the ability of ChatGPT, Gemini, and Copilot to generate chemical representations commonly used in chemistry education, including Lewis structures, molecular geometry, stereochemistry, and molecular polarity. Using identical prompts, the performance of the models was compared between 2025 and 2026 to assess the evolution of their image-generation capabilities. All three LLMs showed substantial improvements in generating Lewis structures and VSEPR geometries for simple molecules while maintaining accurate conceptual explanations of stereochemistry and molecular polarity. However, important limitations remained. The models were unable to consistently generate chemically correct structures for complex molecules and frequently failed to accurately illustrate bond dipole vector addition, despite providing correct textual explanations. These findings demonstrate the rapid evolution of multimodal LLMs for generating chemical representations while highlighting the need for expert verification before AI-generated images are used in chemistry teaching.

Abstract: The catalytic hydrogenation of furfural is a key reaction to valorize lignocellulosic biomass into value-added chemicals. In this work, the influence of different hydrogen donors on furfural hydrogenation under continuous-flow conditions was evaluated using a 10% Pd/C catalyst in a Phoenix Flow Reactor. Molecular hydrogen (H₂), 2-propanol (transfer hydrogenation), and sodium borohydride (NaBH₄) were tested under identical conditions (150 °C, 20 bar, 0.1 mL·min¹). Each hydrogen source led to distinct reaction pathways and product distributions. H₂ promoted selective formation of furfuryl alcohol (FA) via a Langmuir–Hinshelwood mechanism, with transient formation of tetrahydrofurfuryl alcohol (THFA). 2-propanol favored carbonyl reduction while enabling gradual formation of 2-methylfuran (2-MF) at longer reaction times. NaBH₄ yielded FA exclusively through direct hydride transfer but showed operational limitations due to precipitation under flow conditions. Catalyst deactivation was observed in all systems, mainly associated with carbonaceous deposition. While H₂ and 2-propanol showed comparable catalytic efficiency, NaBH₄ exhibited lower efficiency and limited scalability. These results highlight the critical role of hydrogen donor selection in controlling reaction pathways, selectivity, and process feasibility in continuous-flow biomass valorization.

Abstract: At the Late Postclassic site known as Tehuacán-Ndachjian in Puebla, Mexico, the “Los Escudos” mural remains relatively unknown within Mexico due to limited access to the site, which is situated underground on a mountain. To this day, this study represents the first and unique opportunity to analyse samples of mural painting from this archaeological site. Small pigmented samples were analysed using optical microscopy (OM), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDXS), and X-ray diffraction (XRD). The compositional and structural characterisation of the samples revealed the stratigraphic composition without lime plaster layer and the presence of minerals such as hematite, goethite, palygorskite, gypsum and feldspars. These findings support the conclusion that the pictorial technique used to create the mural was “tempera on earth” with mineral pigments. The overall results provide valuable data on the materials and techniques used, serving as a reference for conservators in addressing preservation, conservation, and restoration issues for mural paintings on mud plaster. Furthermore, the study enhances understanding of ancient painting techniques on mud plaster and the technological advances developed by pre-Hispanic cultures in Mexico.

Abstract: Adsorptive interactions between adsorbents and toxic contaminants are significantly exploited to the advantage of water treatment goals. In this study, adsorptive interactions in aqueous solution between Pb (II) ions and a lowly toxic and structurally robust metal organic framework, zinc-trimesate framework (Zn-H3btc), were evaluated using thermodynamic, equilibrium and kinetic models to establish the capacity of the material to adsorb Pb (II) ions from water. Zn-H3btc was synthesized by refluxing mixtures of zinc nitrate and trimesic acid in DMF solvent and characterized using FTIR, SEM, EDS, PXRD, TGA and DTG methods. Adsorption experiments were carried out on basis of variation of initial concentration, contact time, pH, adsorbent dosage, and temperature. Langmuir isotherm was the best fitting isotherm. Maximum monolayer adsorption capacity of Zn-H3btc was 54.05 mg/g. Kinetic studies revealed a pseudo-second order controlled adsorption process, and hence chemisorption mechanism. The thermodynamic parameters, Gibb’s free energy, ∆G, activation energy, E_a, sticking probability, S*, and isosteric heat of adsorption ∆Hx, indicated that the adsorption process was spontaneous, and required a minimal energy barrier, however, had a fairly large amount of isosteric heat (133.39 kJ/mol) released. The findings revealed that Zn-H3btc would be effective in the adsorption of Pb (II) ions from solution.

Abstract: Herein we report the synthesis and full characterisation of Ru(II)-based homobimetallic complexes bridged by diphosphines of the type [(p-cym)RuCl2]2(µ-dppx), where p-cym = η6-1-isopropyl-4-methylbenzene, dppx = dppe (1,2-bis(diphenylphosphino)ethane, 1), tdppe (trans-1,2-bis(diphenylphosphino)ethylene, 2), dppa (bis(diphenylphosphino)acetylene, 3), dcpe (1,2-bis(dicyclohexylphosphino)ethane, 4), and 1,4dppb (1,4-bis(diphenylphosphino)benzene, 5). We also report the mononuclear complexes [(p-cym)RuCl2(κ1-dppx)], where dppx = dppe (6) and tdppe (7). Complexes 2, 4, 5, 6 and 7 were further characterised via single crystal X-ray diffraction analysis. The bi-metallic complexes were synthesised in a straightforward fashion and isolated in good to excellent yields. The mononuclear complexes 6 and 7 are stable in air but exhibit reactions in solution, hindering their use as precursors for the synthesis of bimetallic complexes. The in vitro cytotoxic (anticancer) activities of complexes 1 – 5 were determined via cell vi-ability studies and their IC50 values were derived on HeLa and Ect1/E6E7 cell lines. All complexes displayed only low to moderate activity and selectivity. Strikingly, the cytotoxic profiles of the different complexes varied substantially, highlighting the importance of the bridging ligand itself in the cytotoxic behaviour of the complexes further demonstrating the importance of ligand design in bimetallic complexes.

Abstract: Cobalt-based catalysts using aluminum oxide as a support and 0.025-0.10 wt.% iridium as a second metal were prepared by the impregnation method and tested in steam and dry reforming of a model biogas with a ratio of CH4:CO2=1:1. The processes were carried out in a fixed bed flow reactor under atmospheric pressure, a gas hourly space velocity of 1000-1500 h-1, and temperature varied in the range of 300-800 ºC. The BET surface area, XRD, SEM, TEM, and H2-TPR methods were used to characterize the physicochemical properties of the “fresh” and “spent” samples of catalysts. The catalysts exhibit high and stable activity in the production of syngas from the biogas. Methane was almost completely converted at 750-800ºC in the steam reforming of biogas. Stability tests over 80-100 hours confirmed the catalyst's stable operation. Syngas with a ratio of H2/CO ~ 0.9 is formed in dry reforming of biogas, while in steam reforming the ratio exceeds 1. It is believed that the addition of iridium to Co/Al2O3 causes the improvement of the catalyst performance due to a synergetic effect because of the interaction between Co and Ir.

Abstract: Fungicide residues in food have emerged as a major concern for food safety monitoring due to increasing multiclass contamination associated with intensive agricultural prac-tices, particularly in Southeast Asia. This review critically evaluates recent advances (2019–2026) in microchemical analytical strategies for multiclass fungicide residue de-termination in complex food matrices, with emphasis on analytical performance, sus-tainability, and applicability to regional food systems. Recent developments in minia-turized and green sample preparation techniques, including modified QuEChERS, dis-persive liquid–liquid microextraction, solid-phase microextraction, magnetic solid-phase extraction, and deep eutectic solvent-based extraction, have significantly reduced sol-vent consumption and sample handling while maintaining high recovery, sensitivity, and reproducibility. Coupling these approaches with advanced detection platforms such as UHPLC–MS/MS, GC–MS/MS, and high-resolution mass spectrometry enables simul-taneous determination of multiclass fungicides and metabolites at trace levels. The re-view also discusses current analytical challenges related to highly polar fungicides, ma-trix effects, transformation products, and standard availability. Overall, microchemical analytical approaches provide promising sustainable and high-throughput solutions for fungicide residue monitoring; however, their effectiveness depends strongly on matrix complexity, analyte properties, and rigorous method validation.

Abstract: This study investigated subcritical water extraction (SWE) as an alternative to hydroalcoholic extraction for the production of Echinacea purpurea root extracts standardized to hydroxycinnamic acids (cichoric and caftaric acids). Extractions were performed at 100°C, 125°C, 150°C, and 170°C for 10 min–30 min. The recovery of hydroxycinnamic acids was strongly influenced by extraction temperature, with the highest values obtained within the range of 100°C–125°C. Further optimization identified 110°C for 10min as the optimal condition, yielding the highest cumulative recovery of hydroxycinnamic acids (1.87±0.10% of dry material). In the resulting dry extracts, SWE at 100°C–125°C produced hydroxycinnamic acid contents of 5.5%–7.1%, whereas the total dry extract yield increased from 24%–28% at 100°C to 40%–41% at 150°C–170°C. Higher temperatures, however, reduced hydroxycinnamic acid content to 0.6%–1.7%, indicating degradation of the target compounds. In contrast, total polyphenol recovery increased continuously with temperature, reaching 4.86% at 170°C for 30 min. This was accompanied by marked increases in free caffeic acid and gallic acid, reaching 458.5 mg/100g DW and 945.7 mg/100g DW, respectively, suggesting the release of bound phenolics following partial disruption of plant cell wall structures. SWE also enhanced the extraction of carbohydrates, uronic acids, fructans, proteins and organic acids, demonstrating extensive temperature-dependent modification of the root matrix. 5-HMF was not detected in extracts obtained below 125°C, but increased progressively at higher temperatures, reaching 200 mg/100 g at 170°C. Biological evaluation in HT29 cells showed favorable cytocompatibility of SWE extracts, confirmed by cell viability, morphological assessment and low DNA damage in the Comet assay. Overall, SWE enables the production of hydroxycinnamic acid-standardized E. purpurea extracts without organic solvents, supporting its application in pharmaceutical, nutraceutical, food and cosmeceutical products.

Abstract: In an environment where the sensitivity of information classification is handled, the defined classification of documents is essential for the strategic protection of assets and their operational integrity. Critical information systems supporting naval, maritime and defence organizations depend on the correct classification of sensitive information to ensure operational continuity, information security and organizational resilience. This study examines the risks associated with the misclassification of critical documents. The real historical case that occurred between 1971 and 1976, published in 1979, deals with the declassification of several sensitive documents that were exposed to civilians who had no authorization or need to know about such information. These incidents demonstrate that classification or declassification failures were the result of weak procedures, technical limitations, and/or human error. A hypothetical case will be conducted in contrast to the real case to identify the key vulnerabilities in classification processes and the associated risk assessment. Finally, corrective measures and proposals will be made, including control procedures and improvements regarding reviews of important issues. These measures aim to reduce classification or declassification errors and strengthen the overall governance of specific information management.

Abstract: Waste lubricating oils (WLOs) represent a major stream of hazardous petroleum-based residues, with global generation exceeding 24 million tons annually. Improper disposal of WLOs poses risks to soil, water, and air quality, while their chemical composition makes them a potential secondary resource within circular economy frameworks. This review summarizes conventional, advanced, and emerging technologies reported for the recycling and valorization of WLOs into high-value petrochemicals and carbon-based materials. Established processes such as acid–clay treatment, solvent extraction, and vacuum distillation are discussed together with more recent approaches, including catalytic upgrading, hydrotreatment, membrane separation, and thermochemical conversion methods such as pyrolysis and catalytic cracking. Reported data on process performance, environmental considerations, and economic aspects are comparatively analyzed to outline current trends and technical challenges in WLO recycling. Particular attention is given to thermochemical pathways capable of generating carbonaceous materials, including carbon black, porous carbons, and functional carbon nanostructures with potential applications in adsorption, catalysis, electrochemical systems, and tribological formulations. Hybrid and integrated process configurations described in the literature are highlighted for their potential to improve recovery efficiency, enhance product quality, and reduce environmental burdens. In addition, recent life cycle assessment (LCA) and techno-economic analysis (TEA) studies are reviewed to provide insight into the environmental and economic implications of advanced re-refining systems. Overall, the reviewed literature indicates that WLO recycling represents not only an important element of sustainable lubricant management, but also a promising waste-to-carbon strategy for the production of value-added carbon-based materials and petrochemical products.

Abstract: An anti-contamination agent (Zn/Al–ATMP–LDH) has been synthesized by intercalation and used to correct the abnormal thickening and related operational risks caused by contact contamination between drilling fluids and cement slurries during high-temperature/high-pressure cementing. Experimental results have shown that the agent is chemically stable and exhibits good compatibility with conventional spacer-fluid additives. When compared with the direct addition of amino tris(methylenephosphonic acid) (ATMP), confining ATMP within a layered double hydroxide (LDH) markedly mitigates the retarding effect. At a dosage exceeding 0.3 wt%, the compressive strength of cement stone increases from 0 to 32.84 MPa following curing at 90 °C for 1 day, and continues to develop steadily after 7 days. Following conditioning at 187 °C, 145 MPa and 120 min, the spacer system formulated using the proposed agent as the core component serves to enhance the rheology of the mixed slurry via synergistic adsorption-regulation-dispersion stabilization-controlled release. The mixed slurry maintains stable rheological properties before and after aging with no uncontrolled thickening. When mixing the cement slurry and drilling fluid at a 7:3 volume ratio, the slurry consistency exceeds 60 Bc within 1 h, failing to meet operational requirements. In contrast, the mixed slurry containing the anti-contamination spacer (cement slurry:drilling fluid:spacer = 7:2:1) exhibits a thickening time greater than 300 min, and has been successfully applied in field cementing operations in a well in the Gaomo area.

Abstract: Efficient pretreatment is essential for improving the conversion of lignocellulose into fermentable sugars and bioethanol. In this study, choline chloride–monoethanolamine (ChCl-MEA)-based ternary deep eutectic solvents containing H₂O₂, NaHCO₃, Na₂S, or ethylene glycol were prepared and applied to pretreatment of Dendrocalamus brandisii. Among the tested systems, ChCl-MEA-Na₂S showed the best overall pretreatment performance, achieving 92.8% delignification and 86.1% cellulose retention. It also effectively disrupted lignin–carbohydrate associations, reduced lignin shielding and generated a more accessible cellulose-rich substrate for bioconversion. In the following separation enzymatic hydrolysis and fermentation, 92.2% cellulose in substrate was conversed to glucose and 17.49 g/L ethanol was obtained via the fermentation of enzymatic hydrolysate. Taking the bioconversion of substrate into consideration, the ChCl-MEA-H₂O₂ and ChCl-MEA-Na₂S were recovered for full components utilization. Especially, the carbon dots produced from the degradation compounds in ChCl-MEA-H₂O₂ DESs had favorable antioxidation and antibacterial performance due to the oxygen-containing group caused by oxidation of H₂O₂.

Abstract: Computer-aided drug design (CADD) is undergoing a fundamental paradigm shift driven by the transition from classical biophysical methods to deep learning architectures and generative artificial intelligence. This review analyzes the evolution of molecular docking algorithms. We examine traditional programs (AutoDock Vina, Glide, GOLD) based on stochastic conformational search and empirical scoring functions, which retain the status of gold standard due to the high physical validity of the generated predictions. Software solutions for high-throughput virtual screening, such as distributed pipelines like EasyDock and graphical interfaces like EasyDockVina, are analyzed. Particular attention is paid to the latest generative AI models (DiffDock, GNINA, AlphaFold 3, DynamicBind, FABFlex), which address the computational challenges of blind docking and macromolecular receptor flexibility. We assess the systemic crisis of neural network generalization ability identified in independent benchmarks (PoseBusters, Bento, NextTopDocker) and substantiate the need to integrate the laws of molecular physics into the latent spaces of models. We conclude that the formation of hybrid pipelines, combining the speed of AI with the rigor of classical mechanics, is a necessary development.

Abstract: Porous titanium materials exhibit tremendous potential in the field of photocatalytic dye degradation owing to their unique structural and performance advantages. Although traditional powder materials (such as TiO2 nanoparticles) possess high specific surface area and active sites, they suffer from issues of difficult recovery and low light utilization efficiency . Coating materials address the recovery problem by immobilizing the catalyst; however, their limitations including limited specific surface area, insufficient visible light response, and poor mechanical stability restrict their practical applications. In contrast, bulk materials with in-situ grown nano-sized titanium dioxide on the surface of a titanium core combine high specific surface area, enhanced visible light absorption capacity, and excellent mechanical stability, making them an ideal choice for photocatalytic dye degradation. In this study, nickel-doped porous titanium was used as the substrate, and Nix-TiO2 nanotube films with a three-dimensional (3D) network structure were successfully prepared via an in-situ hydrothermal method. The effects of nickel content (2.5 wt.%, 5 wt.%, 7.5 wt.%, 10 wt.%) and calcination temperature (350 ℃-750 ℃) on the structure, morphology, and photocatalytic performance of the composite materials were systematically investigated. X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and nitrogen adsorption-desorption (BET) techniques were employed to characterize the phase composition, micromorphology, chemical state, and specific surface area of the samples. Methylene blue (MB, 20 mg/L) was selected as the target pollutant to evaluate the photocatalytic activity and stability of the catalysts under simulated sunlight. Results indicated that nickel did not enter the TiO2 lattice but formed nickel oxide (NiO), constructing a semiconductor composite structure. Among all samples, the Ni7.5-TiO2 catalyst exhibited the optimal photocatalytic performance, achieving a 98.35% MB degradation rate within 3 hours and maintaining excellent cyclic stability after 5 consecutive degradation cycles. The optimal calcination temperature was determined to be 450 ℃, at which TiO2 nanotubes were completely in the anatase phase with an intact 3D network structure and high crystallinity. Compared with pure titanium substrates, the porous titanium-based catalyst showed a significant enhancement in adsorption capacity, and nickel doping further improved this performance by increasing the specific surface area and providing more active sites. The synergistic effect of nickel doping and the porous titanium-based nanotube structure effectively narrowed the TiO2 band gap, inhibited the recombination of photogenerated carriers, and improved solar energy utilization efficiency. This study provides a feasible technical approach for the treatment of wastewater containing organic pollutants and enriches the research on modified TiO2 photocatalytic materials.

Abstract: Due to the increasing threat of antibiotic resistance and the emergence of new pathogenic strains, the development of effective combined therapeutic agents represents a crucial direction in the fight against infections. Within this study, several compounds were synthesized in which iodine is present in a coordination complex with antibiotics – sodium sulfathimidine and gentamicin sulfate. The physicochemical parameters of these compounds were investigated using capillary electrophoresis and UV-spectroscopy, along with their cytotoxicity, antimicrobial, and antiviral activities. As a result of this work, two stable compounds, KC-246 and KC-248, were synthesized, demonstrating virus-inhibitory activity against herpes simplex virus and influenza A under extremely low cytotoxicity levels of 0.018–0.106 mg/ml. Additionally, they exhibited antimicrobial activity against representatives of the families Staphylococcaceae, Pseudomonadaceae, Enterobacteriaceae, Enterococcaceae, and yeast-like fungi. The minimum bactericidal concentrations (MBCs) ranged from 0.794 µg/ml to 0.198 µg/ml (KC-246) and from 2.093 µg/ml to 0.523 µg/ml (KC-248).

Abstract: Interest in non-centrosymmetric crystalline materials exhibiting second harmonic genera-tion (SHG) has increased due to their potential applications in optical sensing and bio-sensing. Saccharide-based metal complexes are particularly attractive systems, as chiral sugars can promote non-centrosymmetric crystal packing. In this work, a new lantha-num–β-D-fructose compound, [La(C₆H₁₂O₆)(H₂O)₅]Cl₃ (LaFRUCl), was synthesized by a simple and low-cost method and characterized by single-crystal X-ray diffraction. The compound crystallizes in the orthorhombic space group P2₁2₁2₁ and consists of infinite (La³⁺–fructose)ₙ chains extending along the [001] direction, forming a one-dimensional metal–organic framework. The nonlinear optical response was evaluated using the Kurtz–Perry powder technique with a Nd:YAG laser (1064 nm) and compared to a sucrose ref-erence. The measured SHG efficiency is comparable to that of previously reported alkaline earth metal–sugar analogues. While the SHG emission is significant, evaluation of the compound’s structural stability under aqueous or physiological conditions would be re-quired before considering biological applications.

Abstract: Background: Research on green-synthesized nanomaterials (GSNs) for environmental remediation is growing rapidly, yet data remains fragmented in non-interoperable formats. Methods: We present OntoNanoMat, a comprehensive semantic resource consisting of a modular OWL 2 DL ontology and a curated dataset of case studies. The data was structured into five thematic modules: Identification, Synthesis, Mechanism, Performance, and Provenance. Results: The dataset is provided in three interoperable formats: CSV for tabular analysis, JSON for web applications, and Turtle (RDF) for Semantic Web integration. Technical validation was performed using SHACL shapes and SPARQL query libraries to ensure logical consistency and data integrity. Conclusions: OntoNanoMat provides a FAIR-compliant (Findable, Accessible, Interoperable, and Reusable) foundation for future machine learning applications and knowledge graph integration in sustainable nanotechnology.

Abstract: Background/Objectives: Cocrystallisation is a well-established path for altering the physicochemical properties and bioavailability of active pharmaceutical ingredients (APIs). A common side effect of anti-tubercular medicines is depletion of group B vitamin reserves in TB patients. Co-administration of supplements such as pyridoxine (vitamin B6) during TB therapy may be used to ameliorate the harmful side effects of vitamin B6 deficiency. Methods: Mechanochemical grinding and solvent evaporation experiments using pyridoxine (PN) with 4-aminosalicylic acid (PAS) and separately with pyrazinecarboxylic acid (PCBA) were conducted. The bulk powder and crystal analysis was performed using FTIR, PXRD, DSC, TGA and SCXRD . Results: The isolation and characterization of two multicomponent salts containing pyridoxine, i.e., PN-PAS‧H2O and PN-PCBA. Mechanochemistry is an efficient method for the preparation of cocrystals. Conclusions: The drug-vitamin combinations may be useful for the development of new treatment regimens with improved therapeutic outcomes and reduced adverse effects.

Abstract:

Nickel-supported over SiO₂-CeO₂ mixed oxides were investigated as catalysts for syngas production via the dry reforming of methane. The SiO₂-CeO₂ supports were optimized, playing on the preparation method and ceria loading with the aim of stabilizing nickel nanoparticles, enhancing the catalytic performance, and improving the resistance to coke formation under high-temperature reforming conditions. To investigate the effect of support composition, SiO₂-CeO₂ mixed oxides with ceria contents ranging from 5 to 30 wt% were prepared using two synthesis routes: sol-gel and wetness impregnation methods. A nickel loading of 5 wt% was deposited on the resulting supports. The catalysts were characterized by XRD, N₂ physisorption, temperature-programmed reduction, and Raman spectroscopy. Catalytic activity tests were conducted over reduced catalysts in an H₂-He stream at 750 °C, using a feed mixture containing 15 vol% CH₄ and 15 vol% CO₂ in He. The effect of temperature on catalytic performance was evaluated in the range of 450–800 °C. Thermogravimetric, XRD and Raman analyses of spent catalysts were used to assess carbon deposition and the nature of crystalline phases. The results highlight the role of CeO₂ content and preparation method in determining nickel dispersion, reducibility, catalytic performance in DRM, and coke resistance.

Abstract: We report the crystallization and single-crystal X-ray analysis of the monohydrate hy-drochloride salt of chloroquine, designed CQCl·H2O, an antimalarial drug (CQ) with the formula C₁₈H₂₆ClN₃. The crystal structure reveals a well-defined supramolecular architecture stabilized by an extensive hydrogen-bonding network involving CQH⁺ cations, chloride anions, and water molecules. Notably, this study provides the first crystallographic characterization of a monoprotonated chloroquine salt. Additionally, our findings demonstrate the feasibility of isolating pseudo-polymorphic forms of a commercially available CQ salt via heterogeneous crystallization.