Magnetic cobalt oxide supported organosilica-sulfonic acid as a powerful nanocatalyst for the synthesis of tetrahydrobenzo[a]xanthen-11-ones

A novel core–shell structured magnetic cobalt oxide supported organosilica-sulfonic acid (Co(3)O(4)@SiO(2)/OS-SO(3)H) nanocomposite is prepared through a low-cost, simple, and clean method. The characterization of Co(3)O(4)@SiO(2)/OS-SO(3)H was performed by using Fourier transform infrared (FT-IR) spectroscopy, thermal gravimetric analysis (TGA), powder X-ray diffraction (PXRD), energy dispersive X-ray (EDX) spectroscopy, scanning electron microscopy (SEM), vibrating sample magnetometer (VSM), and transmission electron microscopy (TEM). The TGA and FT-IR results illustrate the high stability of the designed nanocomposite. The SEM image showed a size of about 40 nm for the Co(3)O(4)@SiO(2)/OS-SO(3)H nanoparticles. Furthermore, according to the result of VSM analysis, the saturation magnetization of this nanocomposite was about 25 emu/g. This novel material was used as an efficient nanocatalyst for the synthesis of biologically active tetrahydrobenzo[a]xanthen-11-one derivatives. These products were obtained in high to excellent yields under green conditions. The recoverability and reusability of this catalyst were also investigated under applied conditions.