ABSTRACT In the present study, we report N ‐chlorosuccinimide (NCS)‐promoted direct C─H phosphorothiolation of 1‐aryl‐3‐methyl‐1 H ‐pyrazol‐5(4 H )‐ones with S‐hydrogen phosphorothioates at room temperature. The protocol was found to be simple and efficient to produce a variety of phosphorothiolated products in good to excellent yields (74%–82%). This methodology showcases its significant capability in the modification of intricate molecules during the later stages, thereby presenting a novel pathway for establishing C─S─P bonds.

ABSTRACT Mechanochemical synthetic route involving a simple, solvent‐free grinding technique proved effective for synthesizing four chromone‐based derivatives from chromone‐2‐carboxaldehyde and aromatic amines, affording isolated yields of 80%–81%. The products were characterized using FT‐IR, UV–Vis spectroscopy, NMR, elemental analysis, and mass spectrometry. The UV–Vis spectra showed absorption maxima at 370–393 nm, while the FT‐IR spectra exhibited characteristic C═N stretching frequencies between 1640 and 1693 cm −1 , confirming imine bond formation. The novelty of this work lies in the application of a purely mechanochemical route to access biologically relevant chromone–Schiff bases, combining green synthesis with comprehensive experimental and computational evaluation. Structural optimization and electronic analysis were supported by density functional theory (DFT) calculations. The synthesized compounds were evaluated for their antimicrobial screening against two Gram‐positive ( Staphylococcus aureus and Bacillus subtilis ) and two Gram‐negative bacteria ( Escherichia coli and Proteus vulgaris ), and also two fungal agents ( Aspergillus niger and Candida albicans ). Compounds 2‐((benzo[d]thiazol‐2‐ylimino)methyl)‐4H‐chromen‐4‐one (I) and 2‐(((1H‐benzo[d]imidazol‐2‐yl)imino)methyl)‐4H‐chromen‐4‐one (II) exhibited notable antibacterial activity with minimum inhibitory concentration (MIC) values of 31.25–62.5 µg/cm 3 , whereas compounds 2‐(((4‐acetylphenyl)imino)methyl)‐4H‐chromen‐4‐one (III) and 2‐((phenylimino)methyl)‐4H‐chromen‐4‐one (IV) showed significant antifungal activity with MIC values of 31.25–125 µg/cm 3 . These results highlight the effectiveness of mechanochemistry as an environmentally benign and efficient strategy for generating biologically active chromone–Schiff base derivatives. Overall, this study demonstrates the advantages of mechanochemistry—namely operational simplicity, reduced environmental impact, and high efficiency—as a powerful and green platform for the synthesis of biologically active chromone‐based imine derivatives.

ABSTRACT One of the major challenges for advancing sustainable energy sources is developing a molecularly defined and acid‐stable catalyst for water oxidation. In this study, we investigate an octamolybdate‐type polyoxometalate [{Cu(pzc) 2 }Mo 8 O 26 ]·8H 2 O (Cu POM) (pzc‐pyrazine carboxylic acid), as a potential precatalyst that exhibits remarkable catalytic activity and durability for OER in acidic media on undergoing in situ transformation to r‐POM (CuO and residual Mo─O). r‐POM delivers a low overpotential of 234 mV to achieve a current density of 10 mA cm − 2 , surpassing most reported OER catalysts under comparable conditions. Moreover, it exhibits an exceptional long‐term durability of 23 h at a high current density of 50 mA cm − 2 . Mechanistic investigations, supported by post‐catalytic structural characterization, reveal that Cu POM underwent transformation into r‐POM, which acts as the true catalytic species. The catalyst (r‐POM) provides both robust stability in harsh pH environments that synergistically contribute to its catalytic performance. This work highlights the promise of rationally designed polyoxometalates as next‐generation, acid‐resilient OER electrocatalysts for proton‐exchange membrane water electrolysers.

ABSTRACT A highly efficient and selective protocol for the halogenation of the C─H bond of 4‐aminocoumarin derivatives is reported. This shows that the use of trihaloisocyanuric acids in the synthesis of aminocoumarin derivatives consists of obtaining pharmacologically important compounds using new strategies and transformations. The proposed method has a broad substrate scope and uses ethyl acetate as the solvent. The reaction scope evaluation of 4‐aminocoumarins with different structural characteristics showed that the reaction tolerates electron‐withdrawing groups (compounds 3d–f and 8c–e ) and electron‐donating groups (compounds 3b‐c , 3g , 5 , 7 , and 8b ). A sterically hindered group attached to the nitrogen at C4 was also tolerated in the bromination reaction (compound 3h ), as well as an alkyl group (compound 7 ) and even the absence of a substituent on the nitrogen (compound 5 ). Molecular docking results show that, among the compounds tested, compound 3h stands out. Its predicted interactions with acetylcholinesterase (AChE), monoamine oxidase B (MAO‐B), β‐secretase enzyme (BACE), and N‐methyl‐D‐aspartate receptors (NMDAR) suggest a promising profile for inhibiting these neurochemical enzymes and antagonizing glutamatergic NMDAR, potentially contributing to therapeutic strategies for neurodegenerative diseases such as Alzheimer's disease.

ABSTRACT Both Doxycycline hyclate (DOXH) and Florfenicol (FF), which are commonly utilized in veterinary and human medicine, have become known as aquatic pollutants because of their continued persistence in aquatic environments. Purslane biomass was used to create activated carbon (AC) in this study, which was then characterized using FTIR, BET, TGA, SEM, and EDX. The resulting AC showed a pore volume of 0.397 cm 3 /g and a surface area of 226.62 m 2 /g. Adsorption capability was thoroughly evaluated in relation to a number of operational parameters, such as contact time, absorbent dose, solution pH, temperature, and initially antibiotics concentration. Equilibrium was established within 60 min for both drugs, with optimal performance observed at pH 6.0 using 0.02 g of adsorbent. Equilibrium data were analyzed using nonlinear isotherm models, where the Langmuir model provided the best fit, indicating monolayer adsorption on a homogeneous surface. The maximum monolayer adsorption capacities (qmax) predicted by the Langmuir model were 92.27 mg g − 1 for DOXH and 91.08 mg g − 1 for FF, representing the theoretical adsorption capacity of the adsorbent and not being dependent on a single initial concentration. The pseudo‐second‐order (PSO) model best captured the process, according to kinetic assessment, suggesting that chemisorption controlled the adsorption mechanism.

ABSTRACT Silver (Ag) and selenium (Se) nanoparticles (NPs) have shown significant potential for biomedical applications due to their antimicrobial and anticancer properties, synthesized using a green approach. In this study, Lavandula angustifolia Drujba ( L.A. Drujba ) extract was used to synthesize AgNPs and SeNPs in an economical and environmentally friendly manner. The shape, stability, and average size of AgNPs and SeNPs were characterized using UV–vis spectroscopy, FTIR, TEM, SEM, and zeta potential analysis. Antimicrobial activity tests revealed that AgNPs exhibited higher efficacy against Staphylococcus aureus , MRSA and Pseudomonas aeruginosa , E. coli bacteria, with low MIC values. Additionally, AgNPs effectively inhibited quorum‐sensing pathways in P. aeruginosa , significantly reducing pyocyanin production, biofilm formation, and the expression of quorum‐sensing genes (LasI, LasR, RhlI, and RhlR). SeNPs demonstrated moderate biofilm inhibition but limited quorum‐sensing interference. Cytotoxicity studies using A549 lung cancer cells indicated that both AgNPs and SeNPs reduced cell viability and increased lactate dehydrogenase (LDH) level in a dose‐dependent manner, as confirmed by MTT and LDH assays, respectively. The obtained data underscore the potential of AgNPs and SeNPs synthesized from L.A. Drujba extract for antimicrobial and anticancer therapies.

ABSTRACT In this study, silver nanoparticles (AgNPs) were synthesized through a green chemistry approach using roasted hazelnut inner shells, an abundant agricultural byproduct. The hazelnut shell‐derived AgNPs (HIS‐AgNPs) were characterized by UV‐visible spectroscopy, FT‐IR, SEM, TEM, XRD and zeta potential. UV‐vis revealed a surface plasmon resonance peak at 436 nm, while SEM showed spherical particles of 67.8 ± 25.7 nm in size. HIS‐AgNPs exhibited antimicrobial activity against Staphylococcus aureus , Pseudomonas aeruginosa , and Candida albicans , with inhibition zones of 10, 11, and 15 mm and MIC values of 250, 125, and 62.5 µg mL −1 , respectively. They also strongly inhibited acetylcholinesterase (AChE) and butyrylcholinesterase (BChE), with IC 5 0 values of 4.1 and 2.9 µg mL −1 , suggesting relevance for neurodegenerative disorders. In addition, HIS‐AgNPs achieved > 90% photocatalytic degradation of methylene blue under sunlight within 3 h, following pseudo‐first‐order kinetics. Overall, this work demonstrates the sustainable conversion of hazelnut waste into multifunctional AgNPs with promising biomedical and environmental applications.

ABSTRACT Cellulose synthases (CesA) are widely considered highly substrate‐specific, exclusively utilizing nucleotide‐sugar donors to produce β‐1,4‐glucan. However, several in vivo studies have reported incorporation of N‐acetylglucosamine (GlcNAc) into cellulose under certain metabolic conditions, raising the question of whether CesA can directly utilize UDP‐α‐D‐GlcNAc as a substrate. Here, the recombinant bacterial cellulose synthase complex from Rhodobacter sphaeroides (rBcsA‐B) was employed to address this question biochemically. rBcsA‐B catalyzes uridine diphosphate (UDP) cleavage from UDP‐α‐D‐GlcNAc, although with reduced binding affinity (Km = 1.7 ± 0.5 mM) and catalytic efficiency (Vmax = 0.013 ± 0.008 µM NADH/s) relative to natural substrate UDP‐α‐D‐Glc (Km = 0.7 ± 0.2 mM; Vmax = 0.067 ± 0.02 µM NADH/s). Raman spectroscopic analysis of the reaction pellet revealed bands at 890, 1099, 1372, and 1673 cm − 1 , consistent with glycosidic bonds in β‐chitin conformation. Active site mutagenesis of residues within the QxxRW and FxVTxK motifs, namely R382A, Q379A, and K508A, showed reduced catalytic activity toward both substrates. Whereas R382A and Q379A retained donor‐substrate discrimination, K508A did not, suggesting that K508 contributes specifically to discrimination between the C2‐hydroxyl of UDP‐α‐D‐Glc and the bulkier N‐acetyl group of UDP‐α‐D‐GlcNAc, providing direct biochemical evidence that cellulose synthase possesses an intrinsic capacity to synthesize chitin.

ABSTRACT Metal‐containing ionic liquids (M‐ILs) demonstrate more advantages compared to traditional ionic liquids (ILs), particularly in fields like medicine and drug delivery engineering. Designing and identifying M‐ILs with suitable physicochemical properties is a significant challenge for researchers in various fields of science and industry. This work has investigated a series of chelated ionic liquids (ChILs) based on imidazolium dication with the spacers of Metal‐Schiff bases complex using density functional theory (DFT) calculations. To understand noncovalent interactions (NCIs) such as dispersion and hydrogen bonding and the effect of transition metals in the spacer of dicationic species, three ChILs [ML(mim) 2 ][Cl] 2 , (M: Fe(II), Ni, and Zn) were optimized with M06‐2X‐GD3, B3LYP‐GD3, and M06‐2X functionals. The interaction energies of the ChILs range from −208.24 to −207.80 kcal mol −1 , follow the order [ZnL(mim) 2 ][Cl] 2 < [NiL(mim) 2 ][Cl] 2 < [FeL (mim) 2 ][Cl] 2 . NBO and AIM analyses confirm that [Cl] − anions, in addition to electrostatic interactions, have strong hydrogen bonding with the C2─H4 and C2′─H4′ bonds of the imidazolium rings. Also, some of their physical and chemical properties, such as stability in different solvents, dipole moment, and electrochemical stability, were calculated. This study can be useful in understanding the structure–property relationships of ChILs.

ABSTRACT In the present study we have reported novel geminal dicationic ionic liquids (DILs) and their catalytic application in the Morita–Baylis–Hillman (MBH) reaction. A novel series of thermally stable 2‐hydroxyethylmorpholinium (HEM)‐based dicationic ionic liquids, namely [HEM][Br] 2 , [HEM][BF 4 ] 2 , and [HEM][PF 6 ] 2 , were synthesized and thoroughly characterized using FT‐IR, NMR, and mass spectrometry, and their thermal stability was further evaluated through thermogravimetric analysis. The catalytic performance of the synthesized DILs was evaluated in the MBH reaction in an aqueous medium. Remarkably, the use of only 0.011 mol% of [HEM][PF 6 ] 2 afforded a 97% yield with a significant enhancement in reaction rate. Furthermore, [HEM][PF 6 ] 2 could be efficiently recovered and reused for up to six consecutive cycles without notable loss of activity. The present protocol offers several advantages, including mild reaction conditions, operational simplicity, use of water:ethanol as a green solvent, higher yields, and comparatively shorter reaction times.