γ‐Fe2O3@SiO2‐EC‐ZnII: A Magnetic Recyclable Nanocatalyst for the Synthesis of Spiro[indoline‐3, 9′‐xanthene]trione Derivatives in Aqueous Media

Abstract

AbstractIn this research, ZnII immobilized on creatinated epibromohydrin functionalized γ‐Fe2O3@SiO2 nanoparticles (γ‐Fe2O3@SiO2‐EC‐ZnII) as a novel magnetic nanostructured heterogeneous catalyst has been prepared readily and fully characterized by some spectroscopic and microscopic techniques such as fourier transform infrared spectroscopy (FT‐IR), X‐ray diffraction analysis (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy‐dispersive X‐ray spectroscopy (EDX), thermogravimetric analysis (TGA), vibrating sample magnetometry (VSM), dynamic light scattering (DLS), EDS‐map, inductively coupled plasma atomic emission spectroscopy (ICP‐OES) and CHNS. The above experimental results determined the composition of γ‐Fe2O3@SiO2‐EC‐ZnII and clearly revealed the core‐shell structure nanoparticles are spherical in shape with the particle size in the range of 7–23 nm and superparamagnetic behavior. The magnetic nanostructured catalyst was identified as an efficient catalyst for the rapid synthesis of a library of spiro[indoline‐3, 9‐xanthene]trione derivatives via the condensation reaction of different substituted isatins and dimedone or 1,3‐cyclohexanedione at room temperature in aqueous media. Environmental friendliness, aqueous reaction medium, low cost, high yields, short reaction times, operational simplicity, wide applicability, magnetic recovery of catalyst and reusability up to seven cycles, as the important features of this protocol make the present methodology sustainable and economic.