Synthesis of NiFe₂O₄ nanoparticles (NPs) via the hydrothermal approach in the presence of poly(ethylene glycol) as a capping agent is reported to synthesize the functionalized pyrroles via a multi-component reaction.

Abstract

We report the synthesis of NiFe₂O₄ NPs via the hydrothermal approach in the presence of PEG as a capping agent. The diffractometric and microscopic study confirms the formation of a mixture of nonuniform cube and spherical-shaped cubic crystalline NiFe₂O₄ NPs. PEG acts as a capping agent which controls the crystallite size of the formed particles but it does not have much influence on the size of the particles. The as-synthesized NiFe₂O₄ NPs exhibit superparamagnetic behavior and the presence of PEG does not affect the magnetic properties of the particles. The as-synthesized particles prove to be a highly efficient heterogeneous catalyst for the synthesis of functionalized pyrroles via a multi-component reaction under mild reaction conditions resulting in a 93% yield of the desired product in 2.0 h. The presence of PEG enhances the catalytic activities of the particles. The protocol facilitates the synthesis of a library of functionalized pyrroles with moderate to excellent yields. The catalyst exhibits remarkable recyclability up to six catalytic runs without considerable loss of catalytic activity. This developed protocol offers notable advantages over other reported methods in terms of short reaction time, high yield, simple work-up steps, a mild reaction methodology, broad substrate scope, and environmental friendliness.