Dopamine sulfamic acid-functionalized magnetic Fe3O4 nanoparticles (DSA@MNPs) were prepared by a very simple and inexpensive procedure using commercial materials and characterized by X-ray diffraction (XRD) analysis, thermogravimetric analysis (TGA), Fourier-transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and vibratingsample magnetometry (VSM) techniques. They were employed as an efficient and recoverable catalyst in oxidation of sulfides to sulfoxides and oxidative coupling of thiols to disulfides using hydrogen peroxide as green oxidant at room temperature. This is the first report of application of DSA@MNPs in organic reactions. The supported magnetic nanoparticles could be easily recovered using an appropriate external magnet, minimizing catalyst loss during separation, and reused for several times without any loss of catalytic activity. Also, the amount of sulfamic acid function in the DSA@MNPs was calculated from ion-exchange pH analysis and back titration.
