Abstract
In this study, a functionalized graphene oxide catalyst (GO/f-SiO2/Co) was successfully synthesized by decorating the graphene oxide surface using the attachment of hybrid silane (silica/nitrogen) and chelation with Co (II). The catalyst has been characterized by Fourier Transform Infrared (FT-IR), powder X-ray diffraction (XRD), Energy Dispersive X-ray (EDX), Scanning Electron Microscopy (SEM), Transmission electron microscopy (TEM), Raman spectra, Brunauer-Emmett-Teller (BET), and Thermal Gravimetric (TGA) analyses. The synthesized catalyst was used as an effective heterogeneous catalyst for the synthesis of triazolo[1,2-a]indazole-trione and spiro triazolo[1,2-a]indazole-tetraones derivatives under solvent-free conditions at 90 °C. The high thermal stability, corrosion resistance, and ability of the catalyst to recycle make the catalyst favorable. In addition, easy work-up procedure and short reaction time with high conversion yields (91-97%) are some benefits of the current method.