Synthesis and characterization of silica-coated Fe3O4 nanoparticle@silylpropyl triethylammonium polyoxometalate as an organic–inorganic hybrid heterogeneous catalyst for the one-pot synthesis of tetrahydrobenzimidazo[2,1-b]quinazolin-1(2H)-ones

In this study, silica-coated Fe₃O₄ nanoparticle@silylpropyl triethylammonium polyoxometalate catalyst was fabricated and characterized using atomic absorption, inductively coupled plasma optical emission spectrometry, elemental analysis, thermogravimetric analysis, Fourier-transform infrared, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and vibrating sample magnetometry analyses. The activity of this catalyst was examined in the synthesis of tetrahydrobenzimidazo2,1-b]quinazolin-1(2H)-ones. The bonding of the polyoxometalate to the surface of the nanoparticles exhibited excellent catalytic activity in this synthesis. Besides, the catalyst showed good reusability and recovery from the reaction mixture. Tetrahydrobenzimidazo2,1-b]quinazolin-1(2H)-ones were synthesized in high yields in the presence of inexpensive supported solid acid catalysts under classical heating conditions.