Synthesis and Characterization of H3PW12O40 and H3PMo12O40 Nanoparticles by a Simple Method

In this study H₃PW₁₂O₄₀·9H₂O and H₃PMo₁₂O₄₀·6H₂O (HPA) particles were changed into nano forms by heat-treatment in an autoclave as a simple, repaid, inexpensive and one step method. The particle size of these nanoparticles was around 25 nm. The as-synthesized nanostructures were characterized by dynamic light scattering, X-ray powder diffraction, transmission electron microscopy, Fourier transform infrared spectroscopy and inductively coupled plasma analyzer. Thermal stability of nanoparticles was surveyed by thermal gravimeter analyse. Acidity of prepared nanoparticles was investigated by pyridine adsorption method. Results showed rising acidity by declining particle size of HPA.     

Fe3O4@SiO2-polymer-imid-Pd magnetic porous nanosphere as magnetically separable catalyst for Mizoroki–Heck and Suzuki–Miyaura coupling reactions

The activity of palladium nanoparticles supported on poly (N-vinylpyrrolidone) grafted Fe₃O₄@SiO₂ was investigated in the cross-coupling reactions. We have applied this catalyst under low loading of the supported palladium nanoparticles for the coupling of aryl halides with alkenes (Mizoroki–Heck reaction) and organoboronic acids (Suzuki–Miyaura reaction) in the absence of phosphorous ligands. Short reaction times and excellent yields of the products express the effectiveness of this catalyst. The nanocatalyst can be separated from the reaction mixture by applying a permanent magnet externally and can be reused for six times without appreciable change in catalytic activity. Also, the amount of leaching of Pd nanoparticles has been determined by ICP analysis and results showed low leaching of the metal into solution from the supported catalyst.     

Solvent-free,sonochemical, one-pot,four-component synthesis of 2H-indazolo[2,1-b]phthalazine-triones and 1H-pyrazolo[1,2-b]phthalazine-diones catalyzed by Fe3O4@SiO2-imid-PMAn magnetic nanoparticles

Research on Chemical Intermediates - A practical and green method for the synthesis of 2H-indazolo[2,1-b]phthalazine-triones and 1H-pyrazolo[1,2-b]phthalazine-diones using Fe3O4@SiO2-imid-PMAn...     

M(II) Schiff base complexes (M = zinc,manganese, cadmium,cobalt, copper,nickel, iron,and palladium) supported on superparamagnetic Fe3O4@SiO2 nanoparticles: synthesis,characterization and catalytic activity for Sonogashira–Hagihara coupling reactions

A series of magnetically separable catalysts consisting of Schiff base complexes of metal ions (Zn, Mn, Cd, Co, Cu, Ni, Fe and Pd) supported on superparamagnetic Fe₃O₄@SiO₂ nanoparticles has been prepared. The structural features of the catalysts were characterized by XRD, FTIR, TEM, FE-SEM, DLS, VSM, UV–Vis, TGA, AFM and N₂ adsorption–desorption. Some of the Fe₃O₄@SiO₂/Schiff base complexes were found to be efficient catalysts for the Cu-free and the phosphine free Sonogashira–Hagihara coupling reaction of aryl halides and phenylacetylene. The catalysts are superparamagnetic, and thus could be easily separated by the utilization of an external magnetic field, and could be reused for six cycles without significant loss of activity.     

Synthesis and characterization of Fe3O4@SiO2–polymer-imid–Pd magnetic porous nanospheres and their application as a novel recyclable catalyst for Sonogashira–Hagihara coupling reactions

We demonstrate herein the modification of magnetic nanoparticles and their use as a magnetic nanocatalyst in direct coupling reactions of aryl halides with terminal alkynes. Magnetite particles were prepared by simple co-precipitation method in aqueous medium, and then Fe₃O₄@ SiO₂ nanosphere was synthesized by using nano-Fe₃O₄ as the core, TEOS as the silica source and PVA as the surfactant. Fe₃O₄@SiO₂ was coated with polymeric N-heterocyclic carbene/Pd. The samples were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy, field emission scanning electron microscopy, dynamic light scattering, thermogravimetric analysis, vibration sample magnetometer and N₂ adsorption–desorption isotherm analysis. Poly (N-vinyl imidazole) functionalized Fe₃O₄@SiO₂ nanoparticle was found to be an efficient nanocatalyst in Sonogashira–Hagihara cross-coupling reactions. The nanocatalyst can be easily recovered by a magnetic field and reused for six runs without appreciable loss of its catalytic activity.