Preparation and characterization of Fe3O4@SiO2/APTPOSS core-shell composite nanomagnetics as a novel family of reusable catalysts and their application in the one-pot synthesis of 1,3-thiazolidin-4-one derivatives

Silica/APTPOSS anchored on MnFe2O4 as an efficient nanomagnetic composite for the preparation of spiro-pyrano [2, 3-c] chromene derivatives

The synthesis of Octakis [3- (3-amino propyl triethoxysilane) propyl] octa-silsesquioxane (APTPOSS), a derivative of polyhedral oligomeric silsesquioxane, was utilized to produce an efficient nanocomposite. MNPs@Silica/APTPOSS was characterized through scanning electron microscopy, Fourier transform infrared spectroscopy, vibrating sample magnetometry, X-ray diffraction, and Thermogravimetric analysis. These magnetic nanoparticles, a combination of organic-inorganic hybrid polyhedral oligomeric silsesquioxane, were utilized as a proficient heterogeneous catalyst in the one-pot synthesis of spirooxindoles derivatives. Furthermore, they could be swiftly isolated and reused six times while maintaining their catalytic efficiency.

Synthesis and application of novel urea-benzoic acid functionalized magnetic nanoparticles for the synthesis of 2,3-disubstituted thiazolidin-4-ones and hexahydroquinolines

In this work, we reported the synthesis and application of a new urea-benzoic acid containing ligand [(OEt)3Si(CH2)3-urea-benzoic acid] for the functionalization of silica coated magnetic nanoparticles. The resulting structure, namely Fe3O4@SiO2@(CH2)3-urea-benzoic acid, was characterized through different techniques including FT-IR, SEM, EDX-Mapping, VSM and TGA/DTG analysis. Then, Fe3O4@SiO2@(CH2)3-urea-benzoic acid was applied as a heterogeneous dual acidic and hydrogen bonding catalyst for the synthesis of 2,3-disubstituted thiazolidin-4-ones and hexahydroquinolines under mild and green reaction conditions. More importantly, all of the desired products were obtained with relatively good yields. Also, the catalyst was recovered and reused for four successive runs without significant reduction in yield of the model reaction.

A Green and Efficient Solvent- and Catalyst-Free Ultrasonic Dibenzylation Procedure

A greener improvement was achieved for the synthesis of diverse N,N-dibenzylated compounds from the reaction of various aromatic amines with benzyl bromide using the ultrasound irradiation in solvent- and catalyst-free conditions. The dibenzylation reactions were carried out in different solvents and solvent-free conditions under ultrasound irradiation at various temperatures. The yields were very low in all applied solvents, while in the solvent-free condition and at room temperature, the yields were excellent. Due to obtaining the high reaction yields, the catalyst was not used.

Pd Doped on TCH@SBA-15 Nanocomposites: Fabrication and Application as a New Organometallic Catalyst in the Three-Component Synthesis of N-Benzo-imidazo- or -thiazole-1,3-thiazolidinones

In this study, Pd(II)/TCH@SBA-15 nanocomposites were synthesized by the grafting of 3-chloropropyltriethoxysilane and thiocarbohydrazide on SBA-15 and subsequent deposition of palladium acetates through the ligand-metal coordination method. The structure and morphology of this nanoporous nanocomposite was thoroughly identified by Fourier transform infrared spectroscopy, field emission scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, thermogravimetric analysis, atomic absorption spectroscopy, and Brunauer-Emmett-Teller instrumental analyses. Furthermore, the catalytic activity of this nanocomposite was investigated in the three-component synthesis of 3-benzimidazolyl or benzothiazoleyl-1,3-thiazolidin-4-ones via a reaction of 2-aminobenzimidazole or 2-aminobenzothiazole, aromatic aldehydes, and thioglycolic acid in an acetone-H2O mixture under green conditions. The Pd/TCH@SBA-15 nanocatalyst is demonstrated to exhibit a high catalyzing activity in the three-component reaction of the synthesis of N-heterocyclic thiazolidinones with good to excellent yields. One of the advantages of the suggested method is the direct application of the thiocarbohydrazide ligand to stabilize Pd nanoparticles through formation of a stable ring complex without creating an additional Schiff base step. Moreover, this organometallic nanocatalyst can be recycled several times with no notable leaching or loss of performance.

POSS nanostructures in catalysis

In this review we highlight the use of appealing POSS-based nanostructures for both homogeneous and heterogeneous catalytic applications.

Co-aminobenzamid@Al-SBA-15: a favorable catalyst in synthesis of 2,3-dihydroquinazolin-4(1H)-ones

The novel hybrid Co-aminobenzamid@Al-SBA-15 was synthesized as a modified mesoporous catalyst. To achieve this aim, the obtained materials were investigated by various techniques including Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), N2 adsorption-desorption, field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM) to examine the functional groups, crystallinity, surface area, morphology, particle size distribution and amounts of functional groups, respectively. Co-aminobenzamid@Al-SBA-15 exhibits excellent catalytic activity for the synthesis of 2,3-dihydroquinazolin-4(1H)-ones under mild reaction conditions. The heterogeneous catalyst showed good recyclability and can be reused for ten consecutive cycles without significant loss of its catalytic activity.

C–C and C–H coupling reactions by Fe3O4/KCC-1/APTPOSS supported palladium-salen-bridged ionic networks as a reusable catalyst

This study investigates the potential application of an efficient, easily recoverable and reusable magnetically separable Fe₃O₄/KCC-1/APTPOSS nanoparticle-supported salen/Pd(ii) catalyst for C–C and C–H cross-couplings.

Pd/APTPOSS@KCC-1 as a new and efficient support catalyst for C–H activation

In this study, KCC-1 was functionalized with APTPOSS groups acting as the strong performers so that the Pd NPs were well-dispersed on the fibers of the KCC-1 microspheres.