ChemistrySelect最新文献

Affınity based hybrid nanopolymeric membranes were developed in this work as a support material to immobilize urease. The hybrid membrane exhibits the desired characteristics and has potential applications in biotechnological and biomedical processes, particularly in artificial kidney devices that remove urea from blood. In this study, it was aimed to embed p(GMA) (glycidylmethacrylate) nanoparticles into HEMA(2-hydroxyethylmethacrylate) membranes and use them in urease enzyme immobilization. First, p(GMA) nanoparticles were synthesized with surfactant-free emulsion polymerization method. Then, a hybrid affinity system was developed by embedding p(GMA) nanoparticles in the p(HEMA) polymeric membranes synthesized by the free radical photopolymerization method. Following the characterization studies with dry mass analysis, scanning electron microscopy (SEM) analysis, Fourier-transform infrared spectroscopy (FTIR) analysis, Brunauer–Emmett–Teller (BET) analysis, surface area calculations, and swelling tests of the hybrid membranes, and conditions (pH, temperature, and concentration) were optimized for urease immobilization. Urease was immobilized onto p(GMA) nanoparticles embedded in p(HEMA) hybrid membranes via adsorption. The maximum urease immobilization capacity of the p(GMA) nanoparticles embedded in p(HEMA) hybrid membranes was 31.85 µg/g. The hybrid membrane exhibits the desired characteristics and has potential applications in biotechnological and biomedical processes, particularly in artificial kidney devices that remove urea from blood.

This study compares chemical and green synthesized zinc sulfide nanoparticles for multiple biological properties. A chemical synthesis approach is utilized to synthesize PEGylated ZnS-NPs while the bulbs of Fritillariae cirrhosae bulbus are utilized for green synthesis. After extensive characterization, the NPs are examined for multifunctional biological properties such as antimicrobial, antioxidant, in vitro anticancer, and blood compatibility. Our study found that chemical synthesis results in higher yield and better dispersion behavior. However, the green ZnS-NPs possessed increased antibacterial and antiparasitic potential against Leishmania tropica as the NPs resulted in significant inhibition against Staphylococcus aureus (S. aureus) and Bacillus subtilis (B. subtilis) with minimum inhibitory concentration (MIC) of 0.156 and 0.312 mg/mL, respectively while IC50 of 115.21 and 128.5 µg/mL were observed for the promastigote and amastigote forms of parasite. Furthermore, Fritillaria cirrhosa (F. cirrhosa) synthesized NPs possessed slightly improved antioxidant properties and in vitro anticancer potential against MCF-7 breast cancer cells. Despite differences in the biological properties, the NPs did not result in hemolytic behavior thus demonstrating the compatible nature against blood cells. It was thus evident from the present study that the chemical and green synthesis techniques not only result in NPs with different physicochemical characteristics but also significantly influence the bio-interaction of the obtained ZnS-NPs.

Herein, we developed a metal-free, photosensitized strategy for difunctionalization of olefin feedstocks to access β-amino sulphone architectures, enabled by a tailor-made, readily accessible sulfonylamide bifunctional reagent. This protocol could accommodate a wide range of alkenes and a variety of sulfonylamides, with high yields and excellent regioselectivity. Given remarkably mild reaction conditions, readily accessible starting materials, excellent functional group tolerance, and well-defined regioselectivity, this approach would enable an efficient platform for the assembly of densely functionalized molecular scaffolds.

The formation of a hydrogel for wound dressing can be achieved through the combination of different materials having unique properties. Graviola fruit extract (GrE) not only imparts antimicrobial properties to the hydrogel but also contributes to the potential acceleration of wound healing due to its anti-inflammatory and antioxidant properties. In this study, the freeze–thaw method was employed to create composite hydrogels consisting of polyvinyl alcohol, hyaluronic acid, cross-linked with glutaraldehyde, and GrE. The study evaluated various properties of the gels, including swelling, porosity, gel fraction, and morphology. The obtained results indicated that the physicochemical characteristics of the hydrogels were affected by the level of GrE. The hydrogels had a significant capacity to absorb wound exudate, and their porous structure increased with GrE addition. Our results proved that different GrE-based hydrogels (Gr₁ and Gr₂) treatments exhibited excellent hemolysis, hemostasis, antibacterial activity, and wound healing promotion. They also inhibited proinflammatory cytokines (IL-6 and TNF-α) and exhibited higher wound repair capacity. CD-31 and collagen I increased significantly in wound tissues treated with Gr₁ and Gr₂ hydrogels. So, Gr₁ and Gr₂ hydrogels have demonstrated their potential as valuable local treatment and management for full-thickness wounds.

Cyanidation reactions are an essential method for creating C─CN bonds. Traditional cyanidation reactions usually require the use of highly toxic and unstable cyanide sources, such as NaCN, KCN, CuCN, and TMSCN. K₄[Fe(CN)₆], a product of the coal chemical industry, has the advantages of high yield and low toxicity. It is a very environmentally friendly, safe, and stable cyanide source. Since 2004, K₄[Fe(CN)₆] has emerged as a viable alternative to conventional, highly toxic, and hazardous cyanide sources like NaCN and KCN in cyanidation reactions. Over the past two decades, significant progress has been made in studying green cyanidation reactions involving K₄[Fe(CN)₆]. This paper reviews the advancements in the study of cyanidation coupling reactions between substrates such as aryl halides, sulfonates, aryl carboxylic acids, aromatic aldehydes, acyl chlorides, phenols, benzyl alcohols, and aryl sulfonium salts with K₄[Fe(CN)₆].

Sodium chlorite (NaClO₂) is a new type of air disinfectant, which can oxidize formaldehyde into carbon dioxide (CO₂) on account of releasing chlorine dioxide (ClO₂) gas under acidic condition. Unfortunately, NaClO₂ is prone to moisture absorption and decomposition when exposed to air. In this paper, NaClO₂ was microencapsulated based on emulsion crosslinking method for improving its stability and controlled release properties. Due to their high biocompatibility, sodium alginate (SA) and sodium carboxymethyl cellulose (CMC-Na) were selected as the wall material to prepare NaClO₂-SA/CMC-Na composite microcapsules. The results showed that mean particle size of NaClO₂-SA/CMC-Na composite microcapsules was about 225 nm, and their encapsulation ratio was up to 73.18%. In addition, the thermal stability and environmental tolerance of NaClO₂ are improved greatly through microencapsulating. It was proved by formaldehyde degradation testing that the efficiency of formaldehyde degradation using resulted samples can continue to increase after seven days in pH 6.5 environment, indicating their good controlled-release performance. Moreover, degradation efficiency on 30 µg/mL formaldehyde solution using the resulted microcapsules is up to 97.08%. Meanwhile, after 20 repetition degradation, NaClO₂-SA/CMC-Na composite microcapsules can still continuously degrade formaldehyde gas. Therefore, NaClO₂-SA/CMC-Na composite microcapsules reveal good stability and prolonged action on formaldehyde degradation.

Heterogeneous photocatalysts based on polyoxovanadates with Keggin structure (POV) supported onto zeolite (NH₄ZSM-5) were developed. The amount of POV incorporated was varied from 5% to 30% wt. Catalysts were characterized by N₂ adsorption–desorption isotherms, FT-IR, XRD, DRS UV–vis, TGA, and ³¹P MAS-NMR techniques; and the catalytic activity was evaluated in azo dye degradation. The specific surface area decreased as the POV content increased because of zeolite pore blocking. The XRD patters presented the characteristic peaks of NH₄ZSM-5 and POV, with no additional diffraction peaks, assigned to a well dispersed POV. FT-IR and ³¹P MAS-NMR results confirm that the Keggin structure of [PVW₁₁O₄₀]⁴⁻ anions remain unaltered after their inclusion in the zeolite. The incorporation of POV generated a redshift at the absorption border, determined by DRS UV–vis, which promotes its activity in the visible range. Moreover, while POV content increase the bandgap energy diminishes and the photocatalytic activity increased. The higher photoactivity was 80% of discoloration when 30% wt of POV was incorporated. The characterization and catalytic evaluation indicated that these materials present suitable properties to be used as catalysts in the photocatalytic treatment of wastewater, being the main advantage their easy separation and reuse without significant decrease of the photoactivity.

In this study, MgAlFe-layered double hydroxide (LDH) was prepared using the co-precipitation method, and its performance as a photocatalyst for methylene blue (MB) degradation was evaluated. XRD and FTIR analyses confirmed the crystalline structure and successful incorporation of Al into the LDH layers. SEM and TEM images revealed a uniform morphology and layered structure and UV–vis DRS analysis showed that MgAlFe-LDH has an appropriate band gap for visible light absorption. Photoluminescence studies indicated good charge separation, reducing electron-hole recombination and enhancing photocatalytic performance. The effects of the Mg/Al/Fe molar ratio, illumination time, catalyst dosage, MB concentration, and pH on the degradation efficiency were examined. Optimized conditions of Mg/Al/Fe molar ratio 3:0.9:0.1, 180 min illumination, 10 mg L⁻¹ catalyst, 20 mg L⁻¹ MB, and pH 13 yielded a remarkable 90.4%  MB degradation efficiency. The primary active species in the photocatalytic reaction were identified as hydroxyl radicals (·OH) and holes (h⁺). The incorporation of ternary LDH enhances the photocatalytic performance due to its high stability, versatility, and ability to integrate multiple metal cations. This study broadens the application of LDH in treating organic dye wastewater and provides new insights into the photocatalytic degradation of MB.

Graphene oxide (GO) is a single layer of carbon atoms obtained from the oxidation of graphite by the modified Hummers' method. Sulfuric acid acts as an intercalating agent and allows potassium permanganate to enter the layers to oxidize each layer of graphite to form GO. The resultant GO is highly hydrophilic and less conductive in nature. We further reduced it using a combination of thermal and chemical methods. Thermally reduced GO has been produced by thermal treatment of GO, and chemically reduced GO was obtained by two different reducing agents, such as l-ascorbic acid and sodium borohydride. The degree of oxidation and the purity of the RGO were analyzed using Fourier transform infrared (FTIR), Raman spectroscopy, X-ray diffraction (XRD), and scanning electron microscopy (SEM). FTIR analysis of GO revealed distinct absorption peaks of oxygen-based functional groups that show a higher degree of oxidation of the carbon structure. Upon reduction, the FTIR spectrum exhibits a partial or total removal of the same, which signifies the loss of oxygen and the partial restoration of the graphitic structure. The results emphasize that the carbon-to-oxygen ratio was higher in both reduction methods, but thermal reduction yielded a greater degree of deoxygenation than the other.

A diethyl phosphate (DEP)-catalyzed one-pot synthesis of 2,3-dihydroquinolin-4(1H)-ones in DMF was achieved. Control experiments led to a plausible mechanism involving an intermolecular aldol condensation of 2-aminoacetophenone and aldehyde, followed by a hydrogen bond-driven cyclization. In this process, a series of 2,3-dihydroquinolin-4(1H)-ones were obtained in good yields (48–84%). This strategy features transition metal-free and short reaction times.