Design, Preparation and Characterization of MoO3H-functionalized Fe3O4@SiO2 Magnetic Nanocatalyst and Application for the One-pot Multicomponent Reactions.

Molybdic acid-functionalized silica-based Fe3O4 nanoparticles (Fe3O4@SiO2-MoO3H) are found to be a powerful and magnetically recyclable nanocatalyst. The morphology and structure of this nanocatalyst were investigated by Fourier transform infrared spectroscopy (FT-IR), energy dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), field emission scanning electron microscopy (FE-SEM), thermo gravimetric analyses (TGA), X-ray diffraction (XRD) and vibrating sample magnetometer (VSM) techniques. The high catalytic activity of this catalyst was investigated in the synthesis of pyrano[2,3-c]chromenes, representing potent biologically active compounds. The catalyst can be readily separated by applying an external magnet device and recycled up to 8 times without significant decrease in its catalytic activity, which makes it highly beneficial to address the industrial needs and environmental concerns. Fe3O4@SiO2-MoO3H has many advantages, such as low cost, low toxicity, ease of preparation, good stability, high reusability and operational simplicity.