Search Results (670)

The synthesis, in particular the industrial production, of pharmaceuticals requires a broad arsenal of synthetic reactions capable of selectively forming specific structural motifs and assembling smaller building blocks into complex molecules. The Chan–Evans–Lam cross-coupling reaction, which forms a bond between a N-nucleophile and an aryl group from a boronic acid, catalysed by copper salts, is a typical example of this synthetic route. Considering the toxicity of copper and the stringent regulatory limits for its residues in final pharmaceutical products, a heterogeneous catalytic approach offers a viable alternative for this transformation. In this work, we present a simply and reproducibly synthesized catalyst based on copper nanoparticles supported on reduced graphene oxide (Cu-rGO), with high efficiency in a model Chan–Lam reaction involving benzimidazole and aniline derivatives with substituted boronic acids. Full article

In Proton Exchange Membrane Water Electrolysis (PEMWE), the two-phase flow distribution in the anode field significantly affects overall electrolysis performance. Based on visualized experimental data, in this paper, the reaction kinetics equations were theoretically revised, and a three-dimensional, two-phase, non-isothermal, multi-physics coupled model of the electrolysis was developed and experimentally validated. Four different configurations of rectangular turbulence promoters were designed within the anode serpentine flow field and compared with a conventional serpentine flow field (SFF) in terms of their multi-physics distribution characteristics. The results showed that, in the double-row rectangular block serpentine flow field (DRB SFF), the uniformity of liquid water saturation, temperature, and current density improved by 16.6%, 0.49% and 40.8%, respectively. The normal mass transfer coefficient increased by a factor of 6.3, and polarization performance improved by 6.98%. A cross-arranged turbulence promoter structure was further proposed. This design maintains effective turbulence while reducing flow resistance and pressure drop, thereby enhancing mass transfer efficiency and overall electrolysis performance through improved bubble fragmentation. Full article

Background/Objectives: Notwithstanding the declaration by the World Health Organization in May 2023 regarding the conclusion of the COVID-19 pandemic, new cases of this potentially lethal infection continue to be documented globally, exerting a sustained influence on the worldwide economy and social structures. Contemporary SARS-CoV-2 variants, while associated with a reduced propensity for severe acute pathology, retain the capacity to induce long-term post-COVID syndrome, including in ambulatory patient populations. This clinical phenomenon may be attributable to potential autoimmune reactions hypothetically triggered by antiviral antibodies, thereby underscoring the need for developing novel, universal vaccines against COVID-19. The nucleocapsid protein (N), being one of its most conserved and highly immunogenic components of SARS-CoV-2, presents a promising target for such investigative efforts. However, the protective role of anti-N antibodies, generated during natural infection or through immunization with N-based vaccines, alongside the potential adverse effects associated with their production, remains to be fully elucidated. In the present study, we aim to identify potential sites of homology in structures or sequences between the SARS-CoV-2 N protein and human antigens detected using hyperimmune sera against N protein obtained from mice, rabbits, and hamsters. Methods: We employed Western blot analysis of lysates from human cell lines (MCF7, HEK293T, THP-1, CaCo2, Hep2, T98G, A549) coupled with mass spectrometric identification to assess the cross-reactivity of polyclonal and monoclonal antibodies generated against recombinant SARS-CoV-2 N protein with human self-antigens. Results: We showed that anti-N antibodies developed in mice and rabbits exhibit pronounced immunoreactivity towards specific components of the human proteome. In contrast, anti-N immunoglobulins from hamsters showed no non-specific cross-reactivity with either hamster or human proteomic extracts because of the lack of autoreactivity or immunogenicity differences. Subsequent mass spectrometric analysis of the immunoreactive bands identified principal autoantigenic targets, which were predominantly heat shock proteins (including HSP90-beta, HSP70, mitochondrial HSP60, and HSPA8), histones (H2B, H3.1–3), and key metabolic enzymes (G6PD, GP3, PKM, members of the 1st family of aldo-keto reductases). Conclusions: The results obtained herein highlight the differences in the development of anti-N humoral responses in humans and in the Syrian hamster model. These data provide a foundational basis for formulating clinical recommendations to predict possible autoimmune consequences in COVID-19 convalescents and are of critical importance for the rational design of future N protein-based, cross-protective vaccine candidates against novel coronavirus infections. Full article

Given the known biological activity of both natural and synthetic substituted 1H-phenalen-1-ones, the generation of a small chemically and structurally diverse 1H-phenalen-1-one-based library of compounds was warranted. Herein, we have synthesized several groups of compounds to broaden and improve the chemical diversity of our 1H-phenalen-1-one collection. Additionally, we have also introduced hydroxyl, amides or carboxylic groups onto the core, or nitrogen atoms into the core, to increase the chemical diversity while also lowering the ClogP values to aid their water solubility. Notably, we have also improved the synthetic routes to several compounds of interest and have observed the unexpected formation of phenoxazine and acridin-7-one systems during cross-coupling reactions with polyfunctional anilines. Combining the compounds generated in this work with previous ones has enabled us to create a library of chemically diverse 1H-phenalen-1-one available for screening assays. Evaluation of anti-plasmodial activity against the chloroquine-resistant Plasmodium falciparum strain FCR3 revealed four compounds with notable activity, three of which exhibited IC₅₀ values below 1 µM, while none displayed significant cytotoxicity at 10 µM. Full article

Iminophosphine ligands find extensive applications in homogeneous catalysis; however, their potential antitumor activity is currently being explored. Including biologically active moieties, such as aminoalcohols, could enhance this activity further. Therefore, we have synthesised a novel series of Pd(II) and Pt(II) iminophosphine complexes incorporating aminoalcohols as biologically active moieties to explore the potential of enhancing this activity. The series of Pd(II) complexes includes complexes 2a, 2f, and 2h, which were previously reported by our research group as catalysts in Suzuki–Miyaura cross-coupling reaction in aqueous media. Besides their complete characterisation, some structures have been unequivocally corroborated by single-crystal X-ray diffraction (SC-XRD). To evaluate the cytotoxic potential of the complexes, a preliminary in vitro study was conducted on different cancerous cell lines, including using COS-7 cells as a healthy cell line. Notably, complexes 2e, 2f, and 3b exhibited selectivity towards human chronic myelogenous leukaemia (K562), demonstrating IC₅₀ values of 7.73 ± 1.4 µM, 8.53 ± 1.9 µM, and 8.83 ± 1.5 µM, respectively. Remarkably, the selectivity of these complexes surpassed that of cisplatin. Furthermore, in silico analysis indicated a higher binding energy of these complexes to DNA when compared to cisplatin. Full article

This work describes the straightforward synthesis of a novel heterogeneous palladium catalyst immobilized on magnetic Janus-type silica particles coated with an amphiphilic ionic liquid (IL) layer. The material was prepared via a one-pot process wherein TEOS (tetraethoxysilane) and a bis(triethoxysilane) IL precursor are combined to form hollow shells. The IL motifs are selectively located on the outer surface of the hollow particles and serve as centers for the immobilization of palladium species on the material’s surface. The outer surface also hosts magnetic nanoparticles in close proximity to the palladium sites. Thanks to the uniform coverage of the surface with the amphiphilic IL functionality, the material exhibits a well-balanced wettability with reaction components of different polarities. The catalyst’s activity was tested in the Sonogashira cross-coupling reaction of terminal acetylenes and iodobenzene derivatives in water as the solvent. The results show that the mixed palladium–iron oxide catalyst exhibits higher activity than materials containing either immobilized palladium or iron oxide alone, suggesting a synergistic effect in this reaction. Additionally, the reaction proceeds well in the absence of expensive organic ligands and commonly employed additives such as copper co-catalysts or phase transfer catalysts. Furthermore, the material was also used in the oxidative Sonogashira coupling reaction of phenylboronic acid and phenylacetylene. The catalyst can be easily separated using an external magnet and can be reused several times. The feasibility of producing diphenylacetylene on a gram scale via the Sonogashira cross-coupling reaction was also investigated. Full article

This study presents a sustainable and efficient method for fabricating core–shell structured palladium catalysts using a bacterial template and sol–gel synthesis. This synthesis aligns with green chemistry principles by minimizing waste and enhancing resource efficiency. Our results demonstrate that the bacterial template effectively stabilizes Pd nanoparticles (NPs), preventing significant agglomeration during synthesis and subsequent calcination under different atmospheres and final temperatures. The catalyst samples were characterized by SEM, TEM, XRD, and TGA. The 1 wt% Pd/R@SiO₂ catalyst exhibited high activity in the Suzuki–Miyaura cross-coupling reaction, achieving competitive yields. Furthermore, the catalyst demonstrated a stable performance over five consecutive cycles. This work underscores the potential of biotemplated synthesis as a versatile and eco-friendly platform for producing high-performance, tunable catalysts. Full article

With the increasing global demand for environmental protection and sustainable energy utilization, methanol, as a clean and renewable fuel, has become a research focus in the field of marine engines. However, its application in compression ignition engines faces bottlenecks such as low combustion efficiency and poor stability. Taking the L23/30H marine diesel engine as the research object, this paper establishes a combustion simulation model for a methanol/diesel dual-fuel direct-injection engine. The reliability of the model is ensured through grid independence verification and model calibration, and a coupled chemical reaction kinetic mechanism containing 126 species and 711 elementary reactions is constructed. A systematic study is conducted on the effects of injection strategies, including fuel operating modes, spray development patterns, injection intervals, and injection timing, on combustion characteristics. The results show that under the optimized injection strategy (vertical cross spray + synchronous injection) proposed in this study and operating conditions with a high methanol substitution ratio, the combustion efficiency, dynamic performance, and soot emission control effect of the dual-fuel mode are superior to those of the pure diesel mode. Simulation results show that the combined strategy of vertical cross injection and synchronous injection can significantly increase the indicated thermal efficiency (ITE) by 3.2%, reduce the brake specific fuel consumption (BSFC) by approximately 4.5%, advance the peak heat release by 2 °CA, and remarkably improve the combustion efficiency, while earlier injection timing is beneficial to air–fuel mixing. Further comparison of combustion and emission characteristics under different boundary conditions such as methanol energy ratios and injection pressures reveals that increasing methanol injection pressure, compression ratio, and initial pressure can improve combustion uniformity and reduce soot emissions, but NO_x emissions increase, which requires the coordination of after-treatment technologies. Through the comprehensive optimization of multiple parameters, efficient and clean combustion under a high methanol substitution rate is achieved. This paper provides theoretical support and practical guidance for the technological development of marine methanol dual-fuel engines. In the future, industrial applications can be promoted by combining actual engine tests and after-treatment technologies. Full article

A carbon-supported palladium-containing polysiloxane macrocatalyst (Pd-PDMS) was developed for pharmaceutical-grade cross-coupling reactions. The catalyst demonstrates exceptional year-long stability at room temperature while maintaining full catalytic activity. Pd-PDMS efficiently promotes three pharmaceutically relevant reactions: Suzuki coupling (80% yield), copper-free Sonogashira coupling (90% yield at 55 °C), and Heck coupling (80% yield at 90 °C). The copper-free Sonogashira protocol eliminates toxic copper cocatalysts, phosphine ligands, and organic bases while operating under mild conditions. Most significantly, palladium contamination in products reaches ultra-low levels of 22 ppb (Sonogashira, Suzuki) and 167 ppb (Heck), representing a 60–450-fold improvement over European Medicines Agency requirements (10 ppm). The catalyst exhibits excellent recyclability without activity loss over multiple cycles, with simple washing protocols between uses. Scanning electron microscopy and X-ray photoelectron spectroscopy confirmed uniform Pd-PDMS coating on carbon fibers, while density functional theory calculations revealed specific coordination interactions between the palladium complex and carbon support at 3.26 Å distance. This convergence of pharmaceutical-grade metal contamination control, exceptional stability, and multi-reaction versatility establishes a significant advancement for sustainable cross-coupling catalysis in pharmaceutical applications. Full article

Sodium alginate, a natural anionic polysaccharide, exhibits broad potential applications in food, biomedicine, and environmental engineering due to its favorable biocompatibility, degradability, and functional tunability. This review systematically summarizes its chemical structure, physicochemical characteristics, sources, and extraction methods. It also focused on modification strategies, including chemical approaches (e.g., esterification, oxidation, sulfation, graft copolymerization), physical methods (composite modification, irradiation cross-linking, ultrasound treatment), and biological (e.g., enzyme regulation), and elucidated their underlying mechanisms. In the context of food science, special emphasis is placed on food-compatible chemistries and mild modification routes (such as phenolic crosslinking, enzyme-assisted coupling, and other green reactions) that enable the development of edible films, coatings, and functional carriers, while distinguishing these from non-food-oriented chemical strategies. The review further highlights novel applications of modified sodium alginate in areas including food packaging, functional delivery systems, drug release, tissue engineering, and environmental remediation (heavy metal and dye removal). Overall, this work provides a comprehensive perspective linking modification pathways to food-relevant applications and clarifies how chemical tailoring of alginate contributes to the design of safe, sustainable, and high-performance bio-based materials. Full article

The static topology of surface characteristics and active sites in catalysis overlooks a crucial element: the dynamic processes of optimal pattern formation over time and the creation of intermediate structures that enhance reactions. Nature’s principle of coupling reaction and motion in catalytic processes by enzymes or higher organisms offers a new perspective. This work explores a novel theoretical approach by adding the time dimension to optimise topological variations using the Maximum Entropy Production (MEP) assumption. This approach recognises that the catalyst surface is not an unchanging energy landscape but can change dynamically. The time-dependent transport problem of molecules is here interpreted by a non-equilibrium model used for modelling and predicting dynamic pattern formation in excitable media, a class of active matter requiring an activation threshold. We present a nonlocal reaction–cross-diffusion (RXD) formulation of catalytic reactions that can capture the catalyst’s interaction with the target molecule in space and time. The approach provides a theoretical basis for future deep learning models and multiphysics upscaling of catalysts and their support structures across multiphysics fields. The particular advantage of the RXD approach is that it allows each scale to investigate dynamic pattern-forming processes using linear and nonlinear stability analysis, thus establishing a rule base for developing new catalysts. Full article

Novel tricyclic fluorophores were obtained from 2-aryl-[1,2,4]triazolo[1,5-c]quinazoline-5(6H)-ones through chlorodesoxygenation and subsequent Suzuki–Imamura cross-coupling reactions. Their π-extended analogues were synthesized from 5-(4-bromophenyl)-[1,2,4]triazoloquinazolines. The structure of target fluorophores was confirmed by X-ray single crystal diffraction. Photophysical properties in solutions and solid state were studied. 5-Aminoaryl-substituted [1,2,4]triazolo[1,5-c]quinazolines revealed bright blue fluorescence in toluene (Φ_F > 95%), which can be tuned by solvent polarity, the electronic nature and rigidity of the donor fragment, the π-spacer length, and the annelation pattern. Intramolecular charge transfer (ICT) behaviour was demonstrated using both experimental and theoretical data. Distinct acid-induced spectral and fluorescence changes upon protonation were observed for diethylamino-containing derivatives, indicating their potential applicability as dual-mode (polarity and pH) molecular sensors. Full article

The mixture of enantiomers in pharmaceuticals can lead to adverse effects, as demonstrated by thalidomide, where one enantiomer exhibited therapeutic properties while the other was teratogenic. Currently, efforts are focused on developing efficient catalysts capable of selectively producing a single stereoisomer, particularly in the synthesis of neuropharmaceuticals and NSAIDs. In this context, a new chiral catalyst was synthesized, featuring a palladium core and the dipeptide L-lysine-glycine as a ligand. The catalyst was characterized using various spectroscopic techniques and exhibited enantiomeric excesses of up to 40% in aldol reactions. Additionally, it efficiently promoted Heck cross-coupling reactions, indicating its potential catalytic versatility. Full article

Metal anodes promise improvements in energy density and cost; however, their performance is determined within the first several nanometers at the interface. This review reports on how polymer-based artificial solid electrolyte interphases (SEIs) are engineered to stabilize Li and aqueous-Zn anodes, and how these designs are now evaluated against operando readouts rather than post-mortem snapshots. We group the related molecular strategies into three classes: (i) side-chain/ionomer chemistry (salt-philic, fluorinated, zwitterionic) to increase cation selectivity and manage local solvation; (ii) dynamic or covalently cross-linked networks to absorb microcracks and maintain coverage during plating/stripping; and (iii) polymer–ceramic hybrids that balance modulus, wetting, and ionic transport characteristics. We then benchmark these choices against metal-specific constraints—high reductive potential and inactive Li accumulation for Li, and pH, water activity, corrosion, and hydrogen evolution reaction (HER) for Zn—showing why a universal preparation method is unlikely. A central element is a system of design parameters and operando metrics that links material parameters to readouts collected under bias, including the nucleation overpotential (η_nuc), interfacial impedance (charge transfer resistance (R_ct)/SEI resistance (R_SEI)), morphology/roughness statistics from liquid-cell or cryogenic electron microscopy (Cryo-EM), stack swelling, and (for Li) inactive-Li inventory. By contrast, planar plating/stripping and HER suppression are primary success metrics for Zn. Finally, we outline parameters affecting these systems, including the use of lean electrolytes, the N/P ratio, high areal capacity/current density, and pouch-cell pressure uniformity, and discuss closed-loop workflows that couple molecular design with multimodal operando diagnostics. In this view, polymer artificial SEIs evolve from curated “recipes” into predictive, transferable interfaces, paving a path from coin-cell to prototype-level Li- and Zn-metal batteries. Full article

The synthesis of a small library of fused Cyclic Aryl Amino Carbon (f-CArAC) carbene precursors in the form of 1,1,2,4-tetraaryl-1H-isoindol-2-ium triflate (6), (7-R) (R = ^tBu, CF₃) or 3,3-dimethyl-2,8-bis-arene-substituted-3,4-dihydro-isoquinolin-2-ium hydrogen-dichloride (8) and 2,4,8-tri(substituted)-isoquinolin-2-ium tosylate salts (12) has been achieved. All of them feature an arene incorporated on the annulated benzene ring of the corresponding heterocycle, introduced at the early stages of their synthesis via the Suzuki cross-coupling reaction between 2,6-dibromo-benzaldehyde and the desired aryl boronic acid. The terphenyl-2′carbaldehyde by-products of this Suzuki reaction are useful starting points for the preparation of two new iminium iodide salts (10-R) (R = H, CF₃) as potential precursors to access ACyclic Amino Carbon (ACAC) carbenes. Compounds (6) and (7-^tBu) react readily with hydroxide either in THF or in a biphasic Et₂O/aqueous OH⁻ solution to produce the substituted isoindolinols (13) and (14), respectively. The thermal dehydration of the former generates the corresponding f-CArAC carbene in situ, which is trapped by Cu(I)Cl furnishing, a rare example of a two-coordinate Cu(I) complex (15) supported by this new ligand scaffold. Full article