Reduced zwitterionic graphene oxide sheets decorated with nickel nanoparticles as magnetically and efficient catalyst for A3‐coupling reactions under optimized green experimental conditions

Abstract

A Ni‐based supported reduced zwitterionic graphene oxide N,N‐bis(2‐pyridylmethyl)ethylenediamine 1,3‐propanesultone (GO‐BPED‐PS) material was prepared for the catalysis of A3‐coupling reactions under green experimental conditions. First, the in situ generation of nickel nanoparticles (NiNPs) onto the reduced zwitterionic GO‐BPED‐PS sheets was characterized by various techniques such as Fourier infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), X‐ray diffraction (XRD), scanning electron microscopy (SEM), and vibrating sample magnetometer (VSM) analysis. Moreover, the electron density map of NiNPs onto the reduced zwitterionic GO‐based sheets was produced through the X‐ray crystallographic analysis. Then, the as‐prepared reduced GO‐BPED‐PS NiNPs (rGO‐BPED‐PS@NiNPs) material was used as a heterogeneous catalyst for the three‐component coupling reaction (A3‐coupling reaction) of benzaldehyde, morpholine, and terminal alkynes. The experimental conditions were performed in order to obtain very good green chemistry metrics. In particular, we obtained a high catalytic efficiency when using γ‐valerolactone as solvent, a reaction time of 3 h and a temperature of 100°C. In addition, it was demonstrated that the rGO‐BPED‐PS@NiNPs catalyst could be recycled for 11 times without a significant decrease in its catalytic activity.