Search Results (1,039)

Herein, we present the synthesis of N-(4-fluorobenzyl)-N’-(4-fluorobenzylidene)-4-methylbenzenesulfonohydrazide. The compound has been thoroughly characterized through melting-point determination, ¹H and ¹³C NMR spectroscopy and mass spectrometry. The structure was unequivocally determined by X-ray analysis. The comprehensive analytical data obtained from these techniques confirm the successful preparation and structural integrity of the newly synthesized molecule. Full article

Pancreatic ductal adenocarcinoma is highly malignant with poor prognosis. Its dense tumor microenvironment severely limits the efficacy of conventional chemotherapy and causes severe side-effects. Herein, we adopt the established Schiff-base crosslinked thermoresponsive injectable self-healing poly(2-(2-methoxyethoxy)ethyl methacrylate-co-oligo(ethylene glycol) methyl ether methacrylate-co-aldehyde 2-hydroxyethyl methacrylate)/carboxymethyl chitosan (APMOH/CMCS) hydrogel as the delivery scaffold. By regulating monomer composition, the volume phase transition temperature (T_VPT) of the hydrogel was tuned to around 43 °C to match the therapeutic temperature requirement. Subsequently, copper–metal organic framework (Cu-MOF) nanoparticles co-loaded with 2,2′-azobis(2-methylimidazoline) dihydrochloride (AIPH) and 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) cationic radicals (ABTS·⁺) (denoted as AB@Cu-MOF) were uniformly incorporated into the hydrogel network. Under near-infrared (NIR) irradiation, ABTS·⁺ acts as a photothermal agent to generate hyperthermia for tumor ablation; the elevated temperature further activates AIPH to produce alkyl radicals, which can oxidize inactivated ABTS back to ABTS·⁺ and construct a sustainable photothermal therapy–thermodynamic therapy (PTT-TDT) circulation. Meanwhile, Cu-MOF can consume intracellular glutathione (GSH) to protect active components from deactivation and initiate chemodynamic therapy (CDT) via Fenton-like reactions to produce toxic reactive oxygen species. Benefiting from the thermoresponsive characteristic, the hydrogel undergoes volume shrinkage upon heating, achieving NIR-triggered on-demand drug release with a cumulative release rate of 81.1%. In vitro and in vivo experiments verified that this integrated platform realizes remarkable triple synergistic efficacy of PTT, TDT, and CDT. The tumor volume of the treatment group was merely 13.3% of the control group, and the system also exhibited excellent biocompatibility. Collectively, it offers a feasible and promising intelligent platform for precise local treatment of pancreatic cancer. Full article

Heptamethine cyanine fluorophores are widely used in NIR imaging, due to their excellent photophysical properties. In the present work, new meso-ethoxy substituted heptamethine carbocyanine fluorophores 6a–c were prepared by replacing the meso-chlorine atom on a cyclohexenyl-bridged scaffold through a base-driven S_RN1 substitution reaction with an ethoxy group. Once isolated, the compounds were examined in several solvents to study how strongly the medium influenced their absorption, emission, and brightness. The fluorophores absorbed in the 755–770 nm range and showed their strongest fluorescence in ethanol, whereas their emissions were heavily quenched in buffer solutions. Calculations of the HOMO and LUMO energies supported the observed data. A comparison with indocyanine green (ICG) under continuous light exposure showed that fluorophores 6a–c degraded more slowly and maintained their absorbance for a considerably longer period. Having long hydrophobic alkyl chains raised the hypothesis that they could act as sensors for bovine serum albumin (BSA), which is known for its hydrophobic pockets. Therefore, they were tested for BSA binding both in silico and in cuvette. Fluorophore 6b produced a clear optical response when BSA was added, giving both a red shift and an increase in absorbance and fluorescence. Quantitative analysis of the fluorophore 6b–BSA interaction revealed a dissociation constant (K_d) of 0.75 μM and an apparent binding stoichiometry of approximately 1:1 (Hill coefficient n = 1.25), confirming high-affinity, single-site binding. Using the linear range of the fluorescence titration, the limit of detection (LOD) and limit of quantitation (LOQ) for BSA were determined to be 1.9 and 6.0 μM, respectively. Selectivity experiments demonstrated that fluorophore 6b does not exhibit fluorescence enhancement in the presence of collagen or human parvalbumin, confirming its selectivity toward BSA. These observations suggest that introducing an alkoxy group at the meso-position can improve carbocyanine fluorophores properties and achieve high photostability, with significant potential for various biomedical applications. Full article

Ionic liquids (ILs) are salts that are liquid at or below 100 °C. They are composed entirely of ions and have unique properties like negligible vapor pressure, high thermal stability, and tunable structures. These characteristics make them a promising alternative to traditional, often volatile and toxic organic solvents in the petrochemical industry. They have broad applications in chemical and petrochemical industry processes. Ionic liquids may be applied in the following processes: desulfurization, benzene toluene xylene (BTX) separation, alkylation, and carbon capture units. Two different ionic liquid-based process configurations have been evaluated for BTX separation. It has been found that the process configuration working with 1-ethyl-3methylimidazolium tricyanomethanide ([emim][TCM]) reduces the energy costs and capital expenditures associated with the Morphylane process by 67 and 63%, respectively. It also reduces solvent costs, confirming it as a cleaner alternative. The hydrodesulfurization (HDS) process is operated under harsh conditions, such as high temperature and high pressure and the requirement of a noble catalyst and hydrogen. High-Temperature Hydrogen Attack (HTHA) failure occurs at high temperatures between the gaseous molecular hydrogen contained inside the steel pressure vessel and the carbon atoms located in the steel matrix or in carbides. Methane molecules are produced during this reaction. This phenomenon can consequently lead to a loss of mechanical properties due to surface decarburization and to the formation of defects caused by methane bubbles mainly located at grain boundaries. The application of ionic liquids (ILs) in oil refineries offers significant advantages, such as safety, environmental sustainability, and process efficiency, primarily by serving as versatile alternatives to hazardous traditional solvents and catalysts. Across BTX extraction, carbon capture, and desulfurization/HDS-adjacent service, the recurring barriers are high viscosity, difficult regeneration, solvent cost/inventory and uncertain long-term stability. Full article

A new three-step strategy for the preparation of 1,2-disubstituted 1H-benzo[d]imidazoles has been developed. The approach involved (1) S_NAr addition-elimination of alkyl- or arylamines to 1-fluoro-2-nitrobenzene to give N-alkyl- or N-aryl-2-nitroanilines, (2) acylation of these adducts with acid chlorides to afford N-alkyl- or N-aryl-N-(2-nitrophenyl) amides, and (3) reduction of the aromatic nitro with iron in acetic acid at 95–100 °C, followed by closure of the resulting amine on the amide carbonyl to produce 1,2-disubstituted benzimidazoles in high yields. The sequence gave the benzimidazole products in NMR-pure form with only one purification after Step 2. Thirty-seven derivatives were prepared, providing a broad selection of 1,2-disubstituted benzimidazoles. Interestingly, the reaction of the aniline nitrogen derived from the reduction of the nitro group afforded the final product by addition to the acyl carbonyl, followed by dehydrative aromatization with no competing rearrangement, acyl transfer, or side products. Full article

The synthetic strategy relies on the highly diastereoselective alkylation at the C4 position of L-pyroglutamic acid derivatives, followed by a decarboxylation-allylation process that enables the incorporation of diverse substituents, including aromatic substituents, affording trans-3,5-disubstituted γ-lactams with excellent diastereiosmeric ratio (dr > 98:2). The resulting γ-lactams were efficiently transformed into a series of α,γ-disubstituted γ-amino acids through hydrogenation and acidic hydrolysis. Furthermore, cross-metathesis reactions with styrene and 1-decene enabled the introduction of structurally diverse lipophilic side chains, furnishing the corresponding γ-amino acids in good overall yields (71–77%) and high diastereoisomeric ratio from >98:2 to 92:8. In addition, N-allylation followed by ring-closing metathesis and hydrogenation provided access to a previously unexplored conformationally constrained γ-amino acid. Overall, seven α,γ-disubstituted γ-amino acids, including fluorinated and conformationally restricted derivatives, were synthesized from common intermediates with high stereocontrol. The developed methodology offers a versatile platform for the preparation of structurally diverse and underexplored γ-amino acid building blocks of potential interest in peptide synthesis, medicinal chemistry, and antimicrobial agent development. Full article

4-Methyl-N-(4-methylbenzyl)-N’-(4-methylbenzylidene)benzenesulfonohydrazide was synthesized via N-alkylation. The compound was characterized by nuclear magnetic resonance (NMR) spectroscopy and mass spectrometry (MS). Its molecular structure was unambiguously established by single-crystal X-ray diffraction analysis. The comprehensive spectral and crystallographic data conclusively verify the successful synthesis and structural integrity of this newly prepared compound. Full article

Transfer hydroformylation of alkenes with formaldehyde constitutes a green and sustainable route to aldehydes. In this work, the transfer hydroformylation of styrene with formaldehyde was efficiently catalyzed by [Rh(κ²-dppe)₂]⁺ (A), where dppe stands for 1,2-bis(diphenylphosphino)ethane. The reaction was found to be first order with respect to both Rh and substrate concentrations and fractional order with respect to formaldehyde concentration, in line with the behavior previously reported for 1-hexene. DFT was used to investigate the reaction mechanism by using ethene and [Rh(κ²-dpe)₂]⁺ (A), where dpe stands for 1,2-bis(phosphine)ethane, as simplified models of the substrate and catalyst, respectively, and by considering several functionals. The DFT calculations indicate that M06-L provides the most suitable description of the thermodynamic and activation parameters associated with the elementary steps. The combined analysis of kinetic results and the DFT calculations allowed us to propose a detailed catalytic cycle for this reaction, initiated by the reversible oxidative addition of formaldehyde to complex A to afford [Rh(H)(CHO)(κ²-dppe)₂]⁺ (B, ${\mathit{K}}_{\mathbf{1}}$). Coordination of ethene occurs through partial dissociation of one phosphorus atom of the diphosphine ligand, generating [Rh(H)(alkene)(CHO)(κ²-dppe)(κ¹-dppe)]⁺ (I_B, ${\mathit{K}}_{\mathbf{2}}$), followed by the transfer of the hydride to the alkene to give [Rh(alkyl)(CHO)(κ²-dppe)₂]⁺ (C, ${\mathit{k}}_{\mathbf{3}}$), which is considered the rate-determining step of the process. The cycle is completed by reductive elimination of propanal, thereby regenerating A. The overall activation energy calculated by DFT (Ea = 20.0 kcal mol⁻¹) is in good agreement with the experimental values determined for 1-hexene and styrene (20.1 and 22.9 kcal mol⁻¹, respectively). On the basis of these experimental and DFT results, a mathematical kinetic model with the canonical form $r_0={{\mathit{K}}_{\mathbf{1}}{\mathit{K}}_{\mathbf{2}}\mathit{k}}_{\mathbf{3}}{\left[Rh\right]}_o\left[alkene\right]\left[C{H}_{2}O\right]/\left({1+\mathit{K}}_{\mathbf{1}}\left[C{H}_{2}O\right]\right)$ was developed and fitted using a tandem LMFit/Bayesian approach, allowing the values of K₁ and K₂k₃ to be estimated, with comparatively low uncertainty. Overall, this integrated kinetic, computational, and statistical study provides a consistent mechanistic and quantitative framework for understanding the transfer hydroformylation of alkenes with formaldehyde. Full article

Reducing hospital-acquired infections, especially those related to medical devices, is essential not only to improve patients’ well-being but also to reduce healthcare costs. Among various antibacterial approaches, creating bactericidal device surfaces has been advocated as it reduces the likelihood of antibiotic-resistant strains emerging when antibiotics are used. Functionalizing the device surface with cationic groups, such as quaternary ammonium terminal groups, has been considered an effective approach for killing microbes upon contact. Nonetheless, multiple steps, some of which may require harsh chemical reactions and toxic solvents, are generally required to attach the cationic quaternary ammonium functionalities to the surface. Inspired by the mussel’s capability to bind to various substrates, various novel biomimetic cationic catechol-terminated small molecules having the quaternary ammonium functionality with different alkyl chain lengths were synthesized for the first time. These compounds were used for surface modification of medical-grade titanium using simple immersion approaches: a single-layer procedure or a two-layer approach, in which the first layer was prepared by dopamine immersion, followed by a second immersion in the compound of interest. The surface characteristics and antimicrobial capability against the Gram-negative E. coli and Gram-positive S. aureus were assessed. The likely effects of the alkyl chain length and modification schemes on the surface properties and antibacterial activity are discussed and compared. The highest antimicrobial activity against E. coli was noted on the modified surfaces prepared by the two-layer approach with the cationic compound having the shortest alkyl chain, C1, at 2 mg/mL (DA_C1-2) and 8 mg/mL (DA_C1-8). The DA_C1-8 surface also exhibited the highest antimicrobial activity against S. aureus. These findings indicated that the antibacterial activity of titanium can be greatly improved by selecting the appropriate compound and a proper, facile immersion procedure. Full article

In this work, the activity of vanadium-doped and undoped phosphomolybdic acids with general formulae H_3+nPMo_12−nV_nO₄₀ (n = 0, 1, 2, and 3) was evaluated in the acetalization of furfural with alkyl alcohols. The main focus was to assess how vanadium charge affects the catalytic activity of phosphomolybdic acid and to link these effects to changes in structural properties. The main reaction parameters, such as charge and concentration of the catalyst, temperature, time, type of alcohol and aldehyde, and charges of vanadium and of H⁺ ions, were studied. Various Brønsted acids (sulfuric, p-toluenesulfonic, undoped, and doped phosphomolybdic acids) were evaluated on the condensation reactions of furfural with methyl alcohol. Notably, H₄PMo₁₁VO₄₀ was the most active and selective catalyst for the formation of methyl acetal furfural. Water has a leveling effect on the strength of these acids. Nonetheless, under reaction conditions, the presence of vanadium affected their acidity strength, and it was possible to verify that the vanadium-monosubstituted phosphomolybdic acid was the strongest. The superior performance of H₄PMo₁₁VO₄₀ was attributed to its additional acidity, resulting from the presence of very strong Brønsted acid sites (H⁺) and Lewis acid sites, due to the inclusion of V⁵⁺ ions in its structure. The novelty of this work is the assessment of vanadium-doped phosphomolybdic acids in the homogeneous phase in the condensation reactions of furfural with various alcohols and of methyl alcohol with various aldehydes. Full article

Coal gasification fine ash (CGFA) is a carbon–mineral composite solid waste whose valorization is severely hindered by poor interfacial compatibility with organic media due to its highly polar surface. Here, we report a surface alkylation strategy using haloalkanes with variable chain lengths to systematically tune the surface chemistry and thermo-oxidative behavior of CGFA. Comprehensive spectroscopic characterizations (XPS, FTIR, and ¹³C NMR) confirm successful grafting of alkyl chains, which increases aliphatic C-H content from 24.8% to 43.9% while reducing polar carboxyl groups from 7.9% to 1.6%, with the mineral framework remaining intact. Thermogravimetric analysis reveals that alkylation lowers the onset decomposition temperature from 358 °C to 295 °C and enhances the maximum mass-loss rate. Kinetic analysis shows that grafted alkyl chains act as low-energy initiation sites, reducing the initial activation energy to 95 kJ/mol, while the later-stage oxidation becomes diffusion-limited. Notably, long straight-chain alkylation achieves the best performance, whereas branched chains are less effective due to steric hindrance and pore blockage. This work establishes a clear chain-length-dependent structure–thermal response relationship, positioning alkylated CGFA as a designable precursor for functional carbon materials, intelligent char-forming agents, and tunable components for energy or responsive material systems. Full article

Bacteria pose significant threats to human health, industrial production, and daily life, with widespread microbial contamination remaining a critical challenge for global public health. Conventional porous materials often suffer from insufficient antibacterial efficacy, necessitating the development of advanced antimicrobial systems. Herein, we report a synthetic strategy for fabricating chloride-regenerable porous tubular polymers (HCP-DMH-Cl) via a combination of Friedel–Crafts alkylation and nucleophilic substitution reactions. HCP was initially prepared through a crosslinking reaction via Friedel–Crafts alkylation using FeCl₃ as the catalyst and benzyl alcohol as the monomer. SEM characterization was performed to validate the tubular architectural morphology of HCP. The polymeric N-halamine precursor, HCP-DMH, was subsequently obtained through stepwise bromomethylation and nucleophilic substitution modifications. Upon chlorination, HCP-DMH-Cl exhibited good antibacterial efficacy against both E. coli and S. aureus, coupled with favorable regenerability of its oxidative chlorine content. This approach paves the way for designing next-generation porous media with tailored antibacterial functionality and sustainable chlorine-release capabilities. Full article

This study addresses the synthesis of a new liquid crystalline compound featuring a 3,5-disubstituted isoxazoline and a 1,3-dioxolan-2-one ring, and renewable aromatic building blocks derived from vanilin and benzoic acid. The target compound was synthesized through a multistep synthetic route involving alkylation, esterification, oxime formation, and a 1,3-dipolar cycloaddition reaction. The synthesized compound, 2-methoxy-4-[5-(2-oxo-1,3-dioxolan-4-yl)-4,5-dihydroisoxazol-3-yl]phenyl 4-n-decyloxybenzoate, was isolated and fully characterized by spectroscopic techniques. Liquid crystal behavior was evaluated by DSC and POM. The monotropic mesomorphic behavior of the title compound was dictated by the interplay between molecular architecture and intermolecular organization, with the methoxy substituent and the 1,3-dioxolan-2-one ring critically influencing phase stability and texture morphology. These findings suggest a structure–property relationship and guide ongoing synthetic optimization toward achieving a stable enantiotropic liquid-crystalline phase and further ion-conduction experiments. Full article

In this work, the ability of a series of imidazolium-based ionic liquids (ILs) to depolymerize Kraft lignin through acid hydrolysis was evaluated. ILs featuring two-, four-, and six-carbon alkyl chains combined with [Cl⁻], [BF₄⁻] and [CH₃COOH⁻] anions were studied to determine the influence of cation and anion structure. The twelve ILs were synthesized and characterized by FT-IR and ¹H/¹³C NMR spectroscopy. Results indicate that both the anion and cation significantly affect depolymerization efficiency; specifically, longer alkyl chain lengths correlated with higher conversion percentages. Anion efficacy followed the order: [Cl⁻] > [CH₃COOH⁻] > [BF₄⁻]. Furthermore, reaction temperature did not show a significant impact on conversion within the studied range. Spectroscopic data suggest that bond dissociation follows a Brønsted acid-catalyzed mechanism, evidenced by the reduction of phenolic components and guaiacyl/syringyl units in the recovered lignin samples. Full article