Preparation and characterization of a novel Wells–Dawson heteropolyacid-based magnetic inorganic–organic nanohybrid catalyst H₆P₂W₁₈O₆₂/pyridino-Fe₃O₄for the efficient synthesis of 1-amidoalkyl-2-naphthols under solvent-free conditions

Abstract

A novel magnetic inorganic-organic nanohybrid material H6P2W18O62/pyridino-Fe3O4 (HPA/TPI-Fe3O4) was fabricated and performed as an efficient, eco-friendly, and highly recyclable catalyst for the solvent-free, one-pot, and multi-component synthesis of various substituted 1-amidoalkyl-2-naphthols from the reaction of β-naphthol, an aldehyde, and benzamide with good to excellent yields (47-94%) and in a short span of time (25-60 min). The nanohybrid catalyst was prepared by the chemical anchoring of Wells-Dawson heteropolyacid H6P2W18O62 onto the surface of modified Fe3O4 nanoparticles with N-[3-(triethoxysilyl)propyl]isonicotinamide (TPI) linker. The magnetically recoverable catalyst was easily recycled at least eight times without any loss of catalytic activity. XRD, TEM, UV-vis, and FTIR confirmed that the heteropolyacid H6P2W18O62 is well dispersed on the surface of the solid support and its structure is retained after immobilization on the pyridine modified Fe3O4 nanoparticles. This protocol is developed as a safe and convenient alternate method for the synthesis of 1-amidoalkyl-2-naphthols utilizing an eco-friendly, and a highly reusable catalyst.

Fe3O4@SiO2@ADMPT/H6P2W18O62: a novel Wells–Dawson heteropolyacid-based magnetic inorganic–organic nanohybrid material as potent Lewis acid catalyst for the efficient synthesis of 1,4-dihydopyridines

“…Magnetic susceptibility measurements were carried out using a vibrating sample magnetometer (VSM, Meghnatis Daghigh Kavir Company, Iran) in the magnetic field at room temperature. The preparation and characterization of the heteropolyacid catalyst H 6 P 2 W 18 O 62 , was performed following the previously reported procedures (45).…”

γ‐Fe2O3@Cu3Al‐LDH‐TUD as a new Amphoteric, Highly Efficient and Recyclable Heterogeneous Catalyst for the Solvent‐free Synthesis of Dihydropyrano[3,2‐c]pyrazoles and dihydropyrano[3,2‐c]chromens

“…However, separation of these nanoparticles from the reaction mixture by filtration or centrifugation is frequently difficult and troublesome . In order to ease the removal of nanocatalysts from the reaction products and improve the catalytic activity and recyclability, considerable developments have been made on the synthesis and use of magnetic nanoparticles (MNPs), mainly magnetic nano‐metal oxides , as excellent supports for various catalysts, which can be easily separated from the reaction mixture and recycled simply by an external magnet . In recent years, magnetic nanoparticles (MNPs) have shown a rapid growth in their developments and applications in various industrial and biological areas such as drug delivery, hyperthermia, bioseparations, magnetic resonance imaging (MRI), and catalytic processes .…”

H3PW12O40supported on functionalized polyoxometalate organic–inorganic hybrid nanoparticles as efficient catalysts for three-component Mannich-type reactions in water

“…H 3 PW 12 O 40 have been immobilized on Fe 3 O 4 functionalized nanoparticles [29][30][31] and successfully applied as active species in organic reaction catalysis. 32,33 In this study, organic-inorganic nanohybride of HybPOM was used as a new kind of high surface area material for supporting homogeneous H 3 PW 12 O 40 . The functionalized organic-inorganic polyoxometalates of HybPOM was synthesized by a simple and high yield reaction.…”