Chemistry

In this work, the effect of chitosan concentration in chitosan/nickel composite coatings on their morphology and electrocatalytic activity in hydrogen evolution reaction (HER) was investigated. A series of Chitosan/Ni coatings with chitosan content from 0 to 0.7 wt.% was obtained by nickel electrodeposition onto a preformed biopolymer matrix, enabling targeted control of the roughness and specific surface area of the nickel layers. Morphology and roughness parameters were studied using atomic force microscopy and confocal microscopy. Electrochemical activity in the HER was examined by linear sweep voltammetry. Among the studied electrocatalysts, the Chitosan(0.6)/Ni system showed the best HER efficiency, with an overpotential of −200 mV at a current density of 10 mA/cm². Electrochemical impedance spectroscopy was used to determine the real surface area of the coatings. The Chitosan(0.6)/Ni sample exhibited the largest surface area, explaining its high HER activity. The obtained data revealed a correlation between chitosan concentration, composite morphology, and electrochemical activity, and allowed determination of the optimal composite composition. The results demonstrate the potential of chitosan as an effective structural modifier of nickel coatings and open up possibilities for the targeted design of composite materials with tailored electrochemical properties. Full article

A series of 1,2,3-triazole-linked-thiazolidine-2,4-dione hybrids (SDP1–SDP15) were designed, synthesized, and evaluated for their antidiabetic potential. All structures were characterized by FT-IR and NMR spectroscopy (¹H and ¹³C). All derivatives exhibited significant in vitro inhibition of α-glucosidase (IC₅₀: 24.17–46.41 µg/mL) and α-amylase (23.25–50.66 µg/mL), comparable to the standard drug acarbose (IC₅₀: 25.18 and 32.53 µg/mL) and superior to the reference drug pioglitazone (IC₅₀: 84.24 and 79.74 µg/mL) for α-glucosidase and α-amylase, respectively. Molecule SDP8 emerged as the most potent with an IC50 of 24.17 and 23.25 µg/mL for α-glucosidase and α-amylase, respectively. Further, SDP8 exhibited a higher docking score of −10.7 kcal/mol and −10.4 kcal/mol against α-glucosidase and α-amylase than pioglitazone (−8.1 kcal/mol and −7.7 kcal/mol, respectively), suggesting that interaction with these two enzymes may be the cause for its antidiabetic activity. Furthermore, DFT analysis revealed favorable electronic properties with a low HOMO-LUMO energy gap, whereas ADMET predictions revealed moderate drug-like characteristics with some limitations, such as poor solubility, relatively high lipophilicity, and partial noncompliance with drug-likeness regulations. Overall, these results highlight triazole-linked thiazolidinedione hybrids as promising candidates for further development in T2DM, with SDP8 serving as a preliminary lead requiring additional optimization and validation. Full article

Cholinesterases (ChEs) are irreversibly inhibited by organophosphorous compounds (OP). Then, OP-inhibited ChEs undergo a reaction that progressively decreases reactivatability. This process called “aging” results from dealkylation of the adduct. Aged ChEs are resistant to antidotal oximes. Structural and conformational changes in the aged phosphylated ChE active site pocket impair enzyme reactivatability. Thus, reactivation of aged ChEs was a challenge for more than 70 years. However, it was postulated that realkylation of aged adducts could lead to reactivation of enzymes. This hypothesis was confirmed in 2018 when a new generation of reactivators, electrophilic quinone methide precursors (QMPs), capable of resuscitating or resurrecting aged ChEs were synthesized. The QMP-mediated resurrection process of ChEs by these first “resurrectors” is still very slow. Thus, substantial optimization in the chemical design of new drugs and drug-targeted delivery are needed before the resurrection approach can be translated into clinically viable therapies. However, despite limitations, the first achievements resolving the non-reactivatability issue of OP-aged cholinesterases and successful administration of these new reactivators can be regarded as a major step forward in improving the therapy of OP poisoning. Full article

Understanding the atomic-scale mechanisms of coal pyrolysis is essential for efficient coal utilization and carbon-neutral energy strategies, yet conventional computational approaches often struggle to balance between the high accuracy of quantum-chemical calculations and the efficiency of reactive force fields. To overcome this limitation, we proposed a multiscale computational framework integrating high-throughput density functional theory (DFT) calculations, ReaxFF-based configuration sampling, YARP reaction enumeration, and DPA3-based machine learning potentials (MLPs). Two coal-specific MLPs, DPA3-coal and DPA3-coal@dftb, were constructed and systematically benchmarked on both small molecular systems and larger C20–30 coal fragments extracted from MD simulations. DPA3-coal@dftb model demonstrated significantly improved accuracy over ReaxFF in predicting energies and atomic forces while maintaining good transferability. To balance computational efficiency and accuracy in large-scale simulations, the DPA3-coal model was employed to perform accelerated reactive molecular dynamics simulations of a Solomon-type bituminous coal molecule from 1600 to 2600 K. The simulations revealed temperature-dependent evolution of coke, tar, and gas products, including secondary condensation and deep-cracking processes at elevated temperatures. Higher-level DFT calculations further confirmed the thermodynamic consistency of key reaction pathways involving radical formation, H-transfer, recombination, and CO generation, indicating that coal-specific MLPs provide an effective atomistic tool for investigating mechanistic trends in coal pyrolysis. Full article

Photocycloaddition reactions provide an efficient strategy for converting alkenes into structurally complex and high-value molecules that are often difficult to access under conventional thermal conditions. Herein, two readily accessible triarylamine-based imine molecular cages possessing distinct cavity environments were investigated as supramolecular photocatalysts for reactions of pyridinium-masked enol (PME) substrates with unactivated alkenes. Spectroscopic studies are consistent with the formation of electron donor–acceptor (EDA) interactions between the electron-rich cage frameworks and electron-deficient PME substrates. Upon blue-light irradiation (450 nm), these charge-transfer assemblies undergo photoinduced activation, likely involving single-electron transfer, N–O bond cleavage, and subsequent radical generation. The resulting radical intermediates participate in formal [4 + 2] cycloaddition reactions to afford tetralone derivatives under metal-free conditions. Comparative studies revealed that the two cages produce distinct product distributions and selectivities, suggesting that subtle variations in cage architecture and confined supramolecular environments influence the fate of reactive radical intermediates and the balance between productive cyclization and competing side pathways. While the detailed mechanistic origin of these effects remains unresolved, this work demonstrates the potential of covalent organic cages as structurally tunable platforms for modulating EDA-mediated photochemical reactivity and radical selectivity. Full article

Lubricants contain various types of additives, with corrosion and rust inhibitors being some of the most important. Due to the importance of 2,5-Dimercapto-1,3,4-thiadiazole (DMTD) in the field of corrosion inhibitors, we used it as a key intermediate to synthesize a series of 4-thiazolidinone and 4-imidazolidinone derivatives. This work also includes performing the reaction of DMTD with ethyl chloroacetate, which produced the corresponding ester, followed by the conversion into a hydrazide derivative using hydrazine hydrate. The next step is the condensing of the yielded hydrazide with various aromatic aldehydes yielding Schiff bases, which were subjected to cyclization by means of mercapto acetic acid and ethyl glycinate to produce the target 4-thiazolidinone and 4-imidazolidinone derivatives, respectively. FT IR, ¹H NMR, and ¹³C NMR spectroscopies were involved to confirm the structures of these derivatives. The synthesized derivatives have been evaluated as copper corrosion and rust inhibitors for medium lubricants in accordance with ASTM-D130 and ASTM-D665 standards. Interestingly, some lubricant blends of the synthesized derivatives showed good performance as copper corrosion and rust inhibitors. Full article

Chromene derivatives are important structural motifs in biologically active compounds and functional materials, and the development of efficient strategies for their synthesis remains of considerable interest. In this work, simple and sustainable methodologies were developed for the synthesis of chromene dimers linked through short amidine/geminal diamine spacers or long, flexible alkyl diamine linkers. The amidine and geminal diamine linkers were obtained from 3-aminochromene derivatives via nucleophilic addition of the amino group to triethyl orthoformate or non-phenolic aldehydes in ethanol, at room temperature or under reflux, affording the corresponding dimers in moderate to very good yields. In a complementary approach, flexible alkyl diamide linkers were prepared from diamines and ethyl cyanoacetate, followed by condensation with salicylaldehydes in aqueous hydrogen carbonate solution and subsequent acidic hydrolysis, leading to new chromene dimers in excellent yields. These mild and operationally simple protocols provide efficient access to structurally diverse chromene dimers with potential applications in medicinal chemistry and materials science. Full article

Apple juice is one of the world’s most widely consumed fruit juices and is therefore a common target for economically motivated adulteration (EMA). Such adulteration may involve dilution with water, substitution with other juices, or the addition of exogenous sugars, each requiring robust analytical methods for detection. In this study, we present an improved analytical method for identifying exogenous C4-type sugars in apple juice which utilizes the naturally occurring sorbitol as an endogenous isotopic reference marker. The method uses liquid chromatography coupled to isotope ratio mass spectrometry (LC-IRMS) to determine the δ¹³C values of the major endogenous sugars in apple juice. The study shows that the δ¹³C value of sorbitol can be measured in the same analytical run as the other major sugar components and remains unaffected by the addition of exogenous C4-type sugars to the apple juice. This method offers significant advantages over existing approaches, notably by eliminating the need for extensive sample preparation and multiple analytical methods thereby improving both analytical throughput and ease of use. Full article

Several bioactive compounds, including phenolic and flavonoid substances, have been identified in the aqueous leaf extract of Schinus terebinthifolius (ALE). These compounds are active ingredients in green nanoparticle biosynthesis. Transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX), zeta potential analysis, and FTIR spectral analysis were used to characterize copper oxide nanoparticles (CuNPs) and silver nanoparticles (AgNPs). According to TEM results, AgNPs exhibited somewhat larger diameters (12 ± 4 nm), were spherical with significant aggregation, and displayed a fairly uniform distribution, while CuNPs were primarily quasi-spherical with a narrow size range of about 4–5 nm. CuNPs showed a much more negative zeta potential value of −25.8 mV, indicating good to high colloidal stability, whereas AgNPs had a zeta potential of −15.5 mV, suggesting moderate stability. The main compounds included chlorogenic acid (10,375.28 µg/g), gallic acid (7015.59 µg/g extract), ellagic acid (1571.29 µg/g extract), and rutin (1485 µg/g extract). The antifungal activity of CuNPs and AgNPs was tested at concentrations of 6, 12, 25, 50, and 75 μg/mL on Quercus rubra wood against Fusarium circinatum and Pythium tardicrescens. The greatest inhibition of F. circinatum growth was observed with CuNPs and AgNPs at 75 µg/mL, showing fungal inhibition percentages (FIPs) of 61.48 and 60.74%, respectively. CuNPs and AgNPs at 75 µg/mL exhibited moderate activity against P. tardicrescens, with FIPs of 21.48% and 15.92%, respectively. The MICs for AgNPs and CuNPs were 1.5 and 85 µg/mL with F. circinatum and P. tardicrescens, respectively. Overall, CuNPs and AgNPs demonstrated potential antifungal activity against F. circinatum but moderate activity against P. tardicrescens compared to the control. This ALE from S. terebinthifolius is rich in flavonoids and phenolic compounds, including gallic acid, chlorogenic acid, rutin, ellagic acid, and p-coumaric acid, as identified by HPLC analysis. These biomolecules act as both capping agents, which stabilize the nanoparticles, and reducing agents. Using S. terebinthifolius ALE’s rich phytochemical profile as a reducing and stabilizing agent provides an environmentally friendly method for the green synthesis of CuNPs and AgNPs. Full article

The catalytic reduction of 4-nitrophenol (4-NP) requires highly efficient and cost-effective materials, making Mn-Ni nanostructures a promising candidate. In this study, Mn-Ni nanoparticles with distinct morphologies (specifically spheres, stars, and core–shell structures) were synthesized by tuning the precursor composition. The structural and optical properties of the synthesized catalysts were characterized via electron microscopy and UV-Vis spectroscopy. Kinetic evaluations of the 4-NP reduction demonstrated that the core–shell architecture yielded the highest catalytic activity, outperforming both the star-shaped and spherical nanoparticles. Furthermore, the high-index facets at the tips of the nanostars appeared to have contributed to enhanced catalytic activity by providing additional active surface sites for the reduction process. Ultimately, this work suggests that structural morphology and interfacial interactions play important roles in determining catalytic performance, rather than absolute surface area, providing valuable insights into the design of future bimetallic catalysts. Full article

This study investigated the application of six machine learning regression algorithms such as Random Forest, CatBoost, K-Nearest Neighbours, XGBoost, LightGBM, and Gradient Boosting, paired with Molecular ACCess System (MACCS) key fingerprints for the quantitative prediction of aromatase (CYP19A1) inhibitory potency, expressed as pIC₅₀. A dataset of 187 compounds was assembled from the ChEMBL database (version 33, Target ID: CHEMBL1978) following by systematic data curation workflow encompassing duplicate removal, pIC₅₀ transformation, and activity-based filtering. Model performance was rigorously evaluated using an 80/20 stratified train/test split, 5-fold cross-validation, and Y-randomisation testing to ensure unbiased assessment of predictive generalisation. Feature selection via CatBoost permutation importance on the held-out test set identified the top 20 predictive MACCS keys from an initial 166-bit space, substantially reducing dimensionality and improving generalisation across all models. Among the algorithms evaluated, CatBoost trained on the top 20 features achieved the strongest test-set performance (R² = 0.693, RMSE = 0.794, MAE = 0.659) with the most stable cross-validation R² (0.062 ± 0.304), outperforming all other algorithms. Y-randomisation testing returned an empirical p-value of <0.01, confirming that model performance reflects genuine structure–activity relationships rather than statistical chance. Permutation importance and SHAP analysis identified nitrogen-containing heterocyclic fragments (MACCS_41, MACCS_145) and halide-bearing substructures (MACCS_109) as the primary structural determinants of aromatase inhibitory potency, consistent with established CYP19A1 pharmacophoric requirements. Application of the model to ten representative plasticizers demonstrated that the refined applicability domain (h* = 0.423) accommodated eight of the ten compounds, enabling reliable potency predictions across phthalate esters and bisphenol analogues. These findings establish a transparent and reproducible QSAR framework for first-tier endocrine disruption risk screening of plasticizers and highlight the importance of permutation-based feature selection and applicability domain assessment in QSAR model development. Full article

As key therapeutic targets for symptomatic treatment of Alzheimer’s disease (AD) according to the cholinergic hypothesis, acetylcholinesterase (AChE; EC 3.1.1.7) and butyrylcholinesterase (BChE; EC 3.1.1.8) have been the subject of numerous studies over decades, leading to large collections of different ligands with corresponding AChE and BChE activity. This vast amount of data provides an ideal basis for the implementation of different machine learning (ML) and deep learning (DL) tools in different steps of the drug discovery process. Mainly applied to identify potential strong inhibitors of AChE and to a lesser extent BChE, many quantitative structure–activity relationship (QSAR) models and other predictive tools have been constructed utilizing different ML algorithms and DL techniques with various success depending on the input data and specific context. Here, we provide an extensive overview of such cases reported in the literature in recent years. Full article

Direct Coal Liquefaction (DCL) is a promising route for converting abundant coal resources into liquid fuels, yet its efficiency remains strongly dependent on catalyst performance. In this work, we present an integrated computational framework combining density functional theory (DFT) calculations with machine learning (ML) to investigate iron–sulfur (FeS) cluster catalysts for DCL. DFT calculations were employed to examine hydrogen-donor dissociation and coal-derived radical hydrogenation on representative FeS clusters. The results indicate that the most favorable catalytic pathways arise from the cooperation between metallic Fe sites (Fe_2) and interfacial Fe sites adjacent to sulfur (Fe_1), while sulfur atoms mainly play an indirect structural and electronic modulation role. Based on these mechanistic insights, a database containing thermodynamic and kinetic data for 636 reactions across 50 FeS cluster models was constructed. This dataset was then used to train three ML classifiers, among which the Random Forest model showed the best performance, reaching accuracies of 80% for H-donor cleavage and 93% for radical hydrogenation on the held-out test sets. SHapley Additive exPlanations (SHAP) analysis further showed that descriptors associated with Fe active-site identity were among the most influential variables in both tasks. Overall, this work provides a mechanistically informed and interpretable computational framework for understanding FeS-catalyzed DCL chemistry and for the preliminary screening of catalyst motifs within the chemical space covered by the present FeS cluster library. Full article

The escalating threat of antibiotic resistance, driven by the persistence of tetracycline in aquatic ecosystems, necessitates the development of advanced remediation platforms with high structural efficiency. In this study, a bimetallic Ag-Fe co-doped ZIF-8 framework was strategically engineered to optimize pore accessibility and surface chemical affinity. The resulting nanocomposite exhibited an ultra-high BET surface area of 1322.64 m²/g and a pore volume of 0.502 cm³/g, while maintaining the characteristic structural integrity of the parent ZIF-8. Adsorption benchmarks demonstrated a superior maximum capacity of 417.97 mg/g at pH 8 under ambient conditions. The sequestration process was found to be governed by pseudo-second-order kinetics, while the Freundlich and intraparticle diffusion models accurately described a multilayer adsorption mechanism occurring across heterogeneous active sites. Furthermore, the Ag-Fe-ZIF-8 maintained its structural stability and performance over three consecutive cycles. These findings highlight the potential of bimetallic ZIF-8 derivatives as robust, high-surface-area platforms for the sustainable removal of pharmaceutical pollutants from wastewater, with an adsorption capacity as high as 417.97 mg/g after 3 h. Full article

In the post-Moore era, large-area manufacturing of high-quality two-dimensional (2D) materials remains a central bottleneck for the industrialization of next-generation microelectronic and optoelectronic devices. Conventional mechanical exfoliation is limited by randomness and small lateral size, whereas chemical vapor deposition inevitably introduces grain boundaries, stress, and interfacial contamination, making it difficult to achieve both high quality and scalability. Metal-assisted exfoliation (MAE) enables controllable exfoliation and nondestructive transfer of large-area, high-quality monolayer 2D materials via precise modulation of metal-2D interfacial interactions dominated by strain-induced decoupling and atomic intercalation. This article systematically outlines the interfacial physical mechanisms and technological evolution of MAE, and highlights its state-of-the-art applications in patterned transfer, high-performance field-effect transistors, and complementary logic circuits, aiming to provide a firm theoretical and technical basis for advancing 2D materials from fundamental research toward practical applications. Full article

The combination of gemcitabine (GEM) and olaparib (OLA) shows promise for treating pancreatic cancer, particularly in patients with mutations in the BRCA genes. This work presents the validation of a straightforward, fast, and sensitive chromatographic method for the simultaneous analysis of GEM and OLA, supporting the development of advanced pharmaceutical formulations that combine the two drugs. The efficient chromatographic separation of GEM and OLA was achieved using a C18 column (250 × 4.6 mm, 5 μm) with a mobile phase composed of acetonitrile and water (50:50, v/v), which eluted isocratically at a flow rate of 0.8 mL/min. Determinations were performed using a PDA detector at 243 nm for both drugs. The retention times for GEM and OLA were approximately 3.3 and 4.3 min, respectively. The method was linear (R² > 0.999), with a regression curve in the concentration range of 0.5 to 10.0 μg/mL, demonstrating sensitivity, precision, and accuracy. The recovery rates of the drugs from the pancreatic tissue were higher than 97.0%. The components of a coated liposomal formulation and the pancreatic tissue did not interfere with the analysis, and both drugs demonstrated a low degradation rate under stressful conditions. In conclusion, the validated method was suitable for quantifying GEM and OLA simultaneously, even in a biological matrix, making it feasible to support the development of advanced pharmaceutical formulations that incorporate both drugs, such as liposomes. Full article

Phosphorus is an indispensable key element in life systems and materials science. Here in this work, several cyanoterphenyl-based phosphinic acid-bridged liquid crystal (LC) dimers of 2(CTOn)P (n = 6, 11) and their methyl esterification derivatives of 2(CTOn)P1E have been synthesized through hydrophosphination reaction followed by Suzuki coupling. The cyanoterphenyl LC dimers of 2(CTOn)P and methyl esterified 2(CTOn)P1E exhibit rich enantiotropic LC mesophases such as nematic (N), smectic A (SmA) and highly ordered smectic E (SmE), rather than the monotropic N or twist bend nematic (N_TB) displayed by the analogous phosphinic acid-bridged cyanobiphenyl LC dimers of 2(CBOn)P as reported previously. The phase transition temperatures of the cyanoterphenyl LC dimers 2(CTOn)P are also significantly higher than those of the cyanobiphenyl series, which is attributed to the larger π-conjugated system of cyanoterphenyl as compared with cyanobiphenyl, resulting in much enhanced π-π stacking interactions. However, the significantly enhanced interactions also make them extremely insoluble; thus, a different two-step synthesis pathway combining hydrophosphination with Suzuki coupling reactions was adopted. It is worth pointing out that by combining multiple characterization techniques, including DEPT 135°, ¹³C NMR, and HR-MS spectra, the definite molecular composition and structure of a byproduct with a third pro-mesogen attached via a branching alkyl spacer has been unambiguously demonstrated, which evidently deepens our understanding of the free radical-mediated hydrophosphination reaction mechanism, thereby providing valuable guidance for diminishing side reactions and achieving well-preparation of the high-purity phosphorus-containing LC dimers. Such phosphinic acid functionalized LC materials are envisioned to bear some unique application prospects. Full article

Developing eco-friendly metal oxide nanoparticles (NPs) with plant-based reducing and stabilizing agents offers a sustainable alternative to traditional chemical methods. Nonetheless, the detailed mechanisms by which phytochemicals influence NPs formation, antimicrobial properties, and cytocompatibility remain poorly understood, especially in systems mediated by Vaccinium. This study aimed to synthesize TiO₂ NPs and ZnO NPs using Vaccinium corymbosum (blueberry) extract, analyze their structural and surface characteristics, assess their antimicrobial effectiveness and cytotoxicity, and explore potential molecular mechanisms through computational docking. ZnO NPs were produced via alkaline precipitation (pH 12) from ZnCl₂, while food-grade TiO₂ was mixed with blueberry extract. A comprehensive characterization was carried out using techniques like X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, transmission and scanning electron microscopy (TEM/SEM), dynamic light scattering (DLS), and high-performance liquid chromatography (HPLC) for polyphenol profiling. The antimicrobial activity was tested against Escherichia coli and Salmonella Typhimurium, and the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined. Cytotoxicity was assessed using Gallus gallus domesticus leukocytes and Artemia salina bioassays, and molecular docking simulations were performed to examine polyphenol interactions with the bacterial DNA gyrase subunit B (GyrB). XRD analysis confirmed the presence of wurtzite ZnO (with a crystallite size of 18.2 nm) and anatase TiO₂ (12.8 nm after functionalization). HPLC identified key polyphenols, including quercetin, cyanidin, malvidin, and cyanidin-3-glucoside, with patterns indicating stronger adsorption onto TiO₂ NPs surfaces. ZnO NPs showed higher antimicrobial effectiveness (>90% inhibition at 2 mg/mL; MIC 0.5–1 mg/mL) compared to TiO₂ (72% inhibition at 16 mg/mL; MIC 8–16 mg/mL). Cytotoxicity results indicated concentration-dependent effects. Molecular docking simulations revealed favorable binding energies (−6.2 to −8.4 kcal/mol) for blueberry polyphenols with GyrB, suggesting potential synergistic antimicrobial effects and ROS production. The study highlights a successful green synthesis of bioactive TiO₂ NPs and ZnO NPs using Vaccinium corymbosum extract, where polyphenol surface functionalization enhances both colloidal stability and biological activity. This comparative research offers mechanistic insights into how polyphenol-coated NPs work and supports the development of eco-friendly antimicrobial oxide nanomaterials. Full article

This study presents an efficient and environmentally friendly route for synthesizing succinic acid derivatives via palladium-catalyzed oxidative dicarbonylation of ethylene, utilizing oxygen as the terminal oxidant. By systematically optimizing reaction parameters—including catalyst composition, solvent volume, gas ratio, temperature, and additives—the turnover number (TON) for dimethyl succinate was significantly enhanced to 10,325. This strategy not only demonstrates the potential of CO and ethylene as simple and abundant C1 and C2 building blocks but also highlights the viability of oxygen as a sustainable oxidant. The developed process offers a promising pathway toward the cost-effective and scalable production of biodegradable materials such as poly(butylene succinate) (PBS), with important implications for advancing green synthesis and enabling an autonomous supply chain in the biodegradable polymer industry. Full article