Synthesis of Polyhydroquinoline, 2,3-Dihydroquinazolin-4(1H)-one, Sulfide and Sulfoxide Derivatives Catalyzed by New Copper Complex Supported on MCM-41

Magnetic curcumin-copper graphene oxide as facile and recyclable heterogeneous nanocatalyst for preparation of polyhydroquinolines and sulfoxides

In this research project, a versatile procedure has been designed for the preparation of supported copper@curcumin on magnetic graphene oxide nanoparticles (GO@Fe3O4@Cur-Cu). The structure of prepared nanocatalyst was characterized by several techniques including; Fourier transform infrared, powder X-ray diffraction, thermal gravimetric analysis, energy dispersive X-ray analysis, inductively coupled plasma optical emission spectroscopy, vibrating sample magnetometer, transmission electron microscopy, and scanning electron microscopy analyses. The catalytic properties of GO@Fe3O4@Cur-Cu were examined for the efficient synthesis of polyhydroquinolines as well as the preparation of sulfoxides through selective oxidation of sulfides in the presence of hydrogen peroxide.

Investigating layer-by-layer chitosan-dextran sulfate-coated mesoporous silica as a pH-sensitive drug delivery system

Mesoporous silica nanoparticles (MSNPs) coated by chitosan (CS) were shown to be a proper candidate as a carrier for drug delivery purposes. However, choosing the suitable drug-containing complexes to be applied on MSNPs-CS is of much greater importance to evaluate the possible candidate for an efficient combination of cell viability, drug release kinetics, and atherosclerosis prevention. In this regard, this study concentrates on the synthesis and assessment of coated MSNPs-CS designed for drug delivery purposes. The MSNPs are coated with polyelectrolyte complexes (PEC) composed of CS and dextran sulfate (MSNPs-CS-DX), serving as a versatile drug carrier with favorable biological characteristics. CS-DX is applied to MSNPs without requiring complex or multi-step synthesis procedures. Rosuvastatin, a cholesterol-lowering medication, is chosen for its therapeutic relevance. Additionally, CS-DX is found to relatively impede the uptake of low-density lipoproteins (LDLs) by macrophages, enhancing their potential therapeutic utility. FTIR pattern, FESEM, and TEM images prove MSNPs-CS-DX formation. DLS measurement demonstrates the average particle size of 110 nm for MSNPs, with the combined thickness of CS and DX layers ranging from 10 to 15 nm. BET test is carried out to evaluate the pore size and porosity of structure, showing outstanding results that cause an entrapment efficiency of 57% for MSNPs-CS-DX. Furthermore, the findings demonstrate the pH sensitivity of MSNPs-CS-DX on drug release kinetics. Notably, the CS-DX layer exhibits a significant enhancement in cell viability of human umbilical vein endothelial cells (HUVEC) by approximately 24% within a 24 h timeframe compared to MSNPs lacking CS-DX.

Preparation and characterization of graphitic carbon nitride-supported L-arginine as a highly efficient and recyclable catalyst for the one-pot synthesis of condensation reactions

In this work, graphitic carbon nitride-supported l-arginine (g-C₃N₄@l-arginine) nanocatalyst was synthesized and evaluated using FT-IR, EDX, XRD, TGA, and FESEM analyses. The performance of the prepared nanocatalyst was examined in the synthesis of 1,4-dihydropyridine, 4H-chromene, and 2,3-dihydro quinazoline derivatives. The novel g-C₃N₄@l-arginine nanocatalyst showed high thermal stability, easy separation from reaction media, the capability to be used in various multicomponent reactions, and acceptable reusability.

A nickel nanoparticle engineered CoFe2O4/SiO2-NH2@carboxamide composite as a novel scaffold for the oxidation of sulfides and oxidative coupling of thiols

The purpose of this work was to prepare a new Ni-carboxamide complex supported on CoFe2O4 nanoparticles (CoFe2O4/SiO2-NH2@carboxamide-Ni). The carboxamide host material unit generated cavities that stabilized the nickel nanoparticles effectively and prevented the aggregation and separation of these particles on the surface. This compound was appropriately characterized using FT-IR spectroscopy, FE-SEM, ICP-OES, EDX, XRD, TGA analysis, VSM, and X-ray atomic mapping. The catalytic oxidation of sulfides and oxidative coupling of thiols in the presence of the designed catalyst was explored as a highly selective catalyst using hydrogen peroxide (H2O2) as a green oxidant. The easy separation, simple workup, excellent stability of the nanocatalyst, short reaction times, non-explosive materials as well as appropriate yields of the products are some outstanding advantages of this protocol.

Synthesis of a new Ni complex supported on CoFe2O4 and its application as an efficient and green catalyst for the synthesis of bis(pyrazolyl)methane and polyhydroquinoline derivatives

A novel and magnetic nanocatalyst was synthesized for the synthesis of multicomponent compounds.

New Hydrogen-Bond-Enriched 1,3,5-Tris(2-hydroxyethyl) Isocyanurate Covalently Functionalized MCM-41: An Efficient and Recoverable Hybrid Catalyst for Convenient Synthesis of Acridinedione Derivatives

A new nano-ordered 1,3,5-tris(2-hydroxyethyl) isocyanurate-1,3-propylene covalently functionalized MCM-41 (MCM-41-Pr-THEIC) was designed and prepared at room temperature through a simple procedure. According to various microscopic, spectroscopic, or thermal methods and techniques, the correlation of the catalytic performance of the hybrid mesoporous MCM-41-Pr-THEIC to its structural characteristics was fully confirmed. The new MCM-41-Pr-THEIC organosilica nanomaterials were successfully investigated as a solid mild nanocatalyst through hydrogen-bonding activation provided by its organic moiety, for the pseudo-four-component condensation of dimedone, aldehydes, and ammonium acetate or p-toluidine to afford the corresponding acridinedione derivatives under green conditions. Furthermore, the introduced nanocatalyst could be reused at least four times with negligible loss of its activity, indicating the good stability and high activity of the new hybrid organosilica.

Needle ball-like nanostructured mixed Cu-Ni-Co oxides: Synthesis, characterization and application to the selective oxidation of sulfides to sulfoxides

A mixed nano-metal oxides of Cu-Ni-Co has been synthesized. Several characterization techniques (EDS, XRD, TEM, and SEM) have been used to provide insight into the nature and structure of the catalyst. The size of this mixed metal oxide is 22 nm. The SEM images indicate that the sample with spherical particles, of which spherical assembly is comprised of elongated rod/needle-like subunits pointing radially outward, creates a needle ball-like structure. To efficiently catalyze the selective oxidation of sulfide towards sulfoxide, this heterogeneous catalyst uses an oxidizing agent (hydrogen peroxide- H₂O₂) and a solvent (acetonitrile) in mild conditions. The influence of reaction temperature and sulfide/oxidant molar ratio was evaluated with respect to sulfide conversion and chemoselectivity towards the sulfoxide product. Under optimized conditions, product yields in the range from 70 to 97% were obtained.

Functionalized Ordered Mesoporous Silicas (MCM-41): Synthesis and Applications in Catalysis

Mesoporous silica sieves are among the most studied nano-objects due to their stable pore structure and easy preparation. In particular, MCM-41 have attracted increasing research attention due to their chemical versatility. This review focuses on the synthesis and regioselective functionalization of MCM-41 to prepare catalytic systems. The topics covered are: mono and di-functionalized MCM-41 as basic and acid catalysts, catalysts based on metallic complexes and heteropolyacids supported onto MCM-41, metallic nanoparticles embed onto functionalized MCM-41 and magnetic MCM-41 for catalytic purposes.