Preparation of Ag-doped g-C3 N4 Nano Sheet Decorated Magnetic γ-Fe2 O3 @SiO2 Core-Shell Hollow Spheres through a Novel Hydrothermal Procedure: Investigation of the Catalytic activity for A3 , KA2 Coupling Reactions and [3 + 2] Cycloaddition

The smart nanocarrier containing zein/starch co-biopolymers enhanced by graphitic carbon nitride; exploring opportunities in brain cancer treatment

In this investigation, we present an innovative pH-responsive nanocomposite designed to address challenges associated with using 5-Fluorouracil (5-FU) in cancer therapy. The nanocomposite containing zein (Z), starch (S), and graphitic carbon nitride (g-C3N4) macromolecules is synthesized by a water-in-oil-in-water (W/O/W) double emulsion technique, serving as a carrier for 5-FU. The S/Z hydrogel matrix's entrapment and loading efficiency are greatly improved by adding g-C3N4 nanosheets, reaching noteworthy values of 45.25 % and 86.5 %, respectively, for drug loading efficiency and entrapment efficiency. Characterization through FTIR and XRD validates the successful loading of 5-FU, elucidating the chemical bonding within the nanocomposite and crystalline characteristics. Structural analysis using FESEM, along with DLS and zeta potential measurements, reveals an average nanocomposite size of 193.48 nm, indicating a controlled structure, and a zeta potential of -42.32 mV, signifying a negatively charged surface. Studies on the in vitro release of drugs reveal that 5-FU is delivered more effectively and sustainably in acidic environments than in physiological circumstances. This highlights the fact that the created nanocarrier is pH-sensitive. Modeling release kinetics involves finding the right mathematical conditions representing underlying physicochemical processes. Employing curve-fitting techniques, predominant release mechanisms are identified, and optimal-fitting kinetic models are determined. The Baker kinetic model performed best at pH 7.4, indicating that the leading cause of the drug release was polymer swelling. In contrast, the Higuchi model was most accurate for drug release at pH 5.4, illuminating the diffusion and dissolution mechanisms involved in diffusion. To be more precise, the mechanism of release at pH 7.4 and 5.4 was anomalous transport (dissolution-controlled), according to the Korsmeyer-Peppas mathematical model. The pH-dependent swelling and degradation behavior of S/Z/g-C3N4@5-FU nanocomposite showed higher swelling and faster degradation in acidic environments compared to neutral conditions. Crucially, outcomes from the MTT test affirm the significant cytotoxicity of the 5-FU-loaded nanocomposite against U-87 MG brain cancer cells, while simultaneously indicating non-toxicity towards L929 fibroblast cells. These cumulative findings underscore the potential of the engineered S/Z/g-C3N4@5-FU as a productive and targeted therapeutic approach for cancer cells.

Synthesis of propargylamine: pioneering a green path with non-conventional KA2 coupling approach

The KA2 coupling reaction is a well-explored and versatile method for forming C-C bonds in synthetic chemistry. It is composed of ketone, amine, and alkyne, which play a major role in the synthesis of propargylamines, known for their diverse biological activities and are used in treating neurogenetical disorders. The KA2 coupling is highly challenging due to the low reactivity of ketimines toward nucleophilic attacks with metal acetylide intermediates formed by activating the C-H bond of the alkyne. Despite predominant studies conducted on thermal conditions for KA2 coupling reactions, green and sustainable approaches like non-conventional methods still have a lot to achieve. This review article provides a comprehensive introduction to the non-conventional approach in the KA2 coupling reaction, outlining its mechanisms and exploring future aspects.

Green synthesis of chitosan/polyacrylic acid/graphitic carbon nitride nanocarrier as a potential pH-sensitive system for curcumin delivery to MCF-7 breast cancer cells

A novel pH-sensitive nanocarrier containing chitosan (CS), polyacrylic acid (PAA), and graphitic carbon nitride (g-C₃N₄) was designed via water/oil/water (W/O/W) emulsification to administer curcumin (CUR) drug. g-C₃N₄ nanosheets with a high surface area and porous structure were produced via simple one-step pyrolysis process using thiourea as precursor, and incorporated into CS/PAA hydrogel. X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FT-IR) were used to assess the crystalline structure of the nanocarrier and the interactions between its components, respectively. Scanning electron microscopy (SEM) images revealed a spherical structure and confirmed the g-C₃N₄ impregnation into the CS/PAA matrix. Zeta potential and dynamic light scattering (DLS) provided information about the surface charge and average size distribution. High CUR loading and entrapment efficiencies were obtained, which were further improved upon addition of g-C₃N₄. The release kinetics of drug-loaded CS/PAA/g-C₃N₄ nanocomposites were investigated at pH = 5.4 and pH = 7.4, and the results showed an excellent controlled pH-sensitive release profile. Cell apoptosis and in vitro cytotoxicity were investigated using flow cytometry and MTT analyses. CS/PAA/g-C₃N₄/CUR resulted in the highest rate of apoptosis in MCF-7 breast cancer cells, demonstrating the excellent nanocomposite efficacy in eliminating cancerous cells. CS/PAA hydrogel coated with g-C₃N₄ shows great potential for pH-sensitive controlled drug release.

Fabrication, functionalization and advanced applications of magnetic hollow materials in confined catalysis and environmental remediation

Magnetic hollow-structured functional hybrid materials with unique architectures and preeminent properties have always been an area of extensive research. They represent a subtle collaboration of hollow architecture, mesoporous nanostructure and magnetic character. Owing to the merits of a large void space, low density, high specific surface area, well-defined active sites and facile magnetic recovery, these materials present promising application projections in numerous fields, such as drug delivery, adsorption, storage, catalysis and many others. In this review, recent progress in the design, synthesis, functionalization and applications of magnetic hollow-meso/nanostructured materials are discussed. The first part of the review has been dedicated to the preparation and functionalization of the materials. The synthetic protocols have been broadly classified into template-assisted and template-free methods and major trends in their synthesis have been elaborated in detail. Furthermore, the benefits and drawbacks of each method are compared. The later part summarizes the application aspects of confined catalysis in organic transformations and environmental remediation such as degradation of organic pollutants, dyes and antibiotics and adsorption of heavy metal ions. Finally, an outlook of future directions in this research field is highlighted.

Silver nanoparticles-decorated Preyssler functionalized cellulose biocomposite as a novel and efficient catalyst for the synthesis of 2-amino-4H-pyrans and spirochromenes

Silver nanoparticles-decorated Preyssler functionalized cellulose biocomposite (PC/AgNPs) was prepared and fully characterized by FTIR, UV–vis, SEM, and TEM techniques. The preparation of PC/AgNPs was studied systematically to optimize the processing parameters by Taguchi method using the amount of PC, reaction temperature, concentration of silver nitrate and pH of medium. Taguchi’s L9 orthogonal (4 parameters, 4 level) was used for the experimental design. The SEM analysis confirmed the presence of the Preyssler as a white cloud as well as spherical AgNPs on the surface of cellulose. The formation of AgNPs on the surface was observed by changing of the color from yellow to deep brown and confirmed by UV–vis spectroscopy. The best yield of AgNPs forming was obtained in pH 12.5 at 80 ºC in 20 min. TEM analysis confirmed the formation of spherical AgNPs with a size of 50 nm, at the 1% wt. loading of Preyssler. This easily prepared PC/AgNPs was successfully employed as an efficient, green, and reusable catalyst in the synthesis of a wide range of 2-amino-4H-pyran and functionalized spirochromene derivatives via a one-pot, multicomponent reaction. The chief merits realized for this protocol were the utilization of commercially available or easily accessible starting materials, operational simplicity, facile work-up procedure, obtaining of high to excellent yields of the products and being done under green conditions. The catalyst could be easily separated from the reaction mixture and reused several times without observing any appreciable loss in its efficiency.

Pd on poly(1-vinylimidazole) decorated magnetic S-doped grafitic carbon nitride: an efficient catalyst for catalytic reduction of organic dyes

A novel magnetic catalyst, (SGCN/Fe₃O₄/PVIs/Pd) was synthesized by growing of poly(1-vinylimidazole) on the surface of ionic liquid decorated magnetic S-doped graphitic carbon nitride, followed by stabilization of palladium nanoparticles. Catalytic activity of the prepared heterogeneous catalyst was explored for the catalytic reduction of hazardous dyes, methyl orange and Rhodamine B, in the presence of NaBH₄. Besides, the effects of the reaction variables on the catalytic activity were investigated in detail. The kinetics study established that dye reduction was the first order reaction and the apparent activation energy was calculated to be 72.63 kJ/mol and 68.35 kJ/mol¹ for methyl orange and Rhodamine B dyes, respectively. Moreover, ΔS^# and ΔH^# values for methyl orange were found to be − 33.67 J/mol K and 68.39 kJ/mol respectively. These values for Rhodamine B were − 45.62 J/mol K and 65.92 kJ/mol. The recycling test verified that the catalyst possessed good stability and reusability, thereby making it a good candidate for the catalytic purposes. Furthermore, a possible catalytic mechanism for dye catalytic reduction over SGCN/Fe₃O₄/PVIs/Pd was proposed.

Green synthesis of Ag NPs on magnetic polyallylamine decorated g-C3N4 by Heracleum persicum extract: efficient catalyst for reduction of dyes

Silver nanoparticles were immobilized on magnetic polyallylamine (PAA) decorated g-C₃N₄ by using Heracleum persicum extract as a biological reducing and stabilizing agent. The resulting nanocomposite, Fe₃O₄-g-C₃N₄-TCT-PAA-Ag, was then characterized using BET, VSM, XRD, TGA, FTIR, TEM, EDS and ICP. The catalytic performance of the synthesized nanocatalyst was considered in the reduction of rhodamine B, and methyl orange in the presence of sodium borohydride in the aqueous medium at room temperature. The results showed that Fe₃O₄-g-C₃N₄-TCT-PAA-Ag nanocomposite could promote both reduction reactions efficiently in very short reaction times (70-100 s). In addition, Fe₃O₄-g-C₃N₄-TCT-PAA-Ag could be magnetically recovered and recycled for several cycles with no significant decrease in its catalytic performance. Using the experimental results, the rate constant, enthalpy, and entropy of the reduction reactions of both dyes were estimated.