Sonochemically synthesized ferromagnetic Fe3O4 nanoparticles as a recyclable catalyst for the preparation of pyrrolo[3,4-c]quinoline-1,3-dione derivatives

Abstract

This paper reports the green, rapid synthesis of Fe₃O₄ nanoparticles by the ultrasonic irradiation of Fe₂O₃ solution and Perilla frutescens (P. frutescens) leaf extract, which was used as both reducing and capping agent. The synthesized Fe₃O₄ nanoparticles were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive X-ray analysis, vibrating sample magnetometry, thermogravimetric analysis (TGA) and X-ray photoelectron spectroscopy (XPS). The FT-IR spectra indicated that the bioactive molecules present in the plant extract contain polyols, which act as a reducing as well as capping agent, as confirmed by TGA. TEM and SEM showed that the Fe₃O₄ nanoparticles were approximately spherical in shape with a mean size of 50 nm. The synthesized Fe₃O₄ nanoparticles exhibited ferromagnetic behavior with a saturation magnetization of 25.15 emu g⁻¹. The Fe₃O₄ nanoparticles, with their easy recovery by an external magnetic field, exhibited strong catalytic activity towards pyrrolo[3,4-c]quinoline-1,3-dione derivatives. These results suggest that the Fe₃O₄ nanoparticles produced can be applied as a catalyst in organic synthesis and recycled at least five times without significant loss in its activity.