Ultrasonic-Assisted Preparation, Characterization, and Use of Novel Biocompatible Core/Shell Fe3O4@GA@Isinglass in the Synthesis of 1,4-Dihydropyridine and 4H-Pyran Derivatives

This work focussed on the synthesis of a new catalytic material isinglass (IG)-based Fe 3 O 4 @GA@IG core/shell magnetic nanoparticles and the investigation of its catalytic activity in two important multicomponent reactions. Fe 3 O 4 nanoparticles were prepared using a simple coprecipitation method and then coated with IG consisting predominantly of the protein collagen in the presence of glutaraldehyde as a cross-linking agent. The obtained hybrid material has been characterized by Fourier transform infrared analysis, scanning electron microscopy, transmission electron microscopy (TEM), vibrating sample magnetometry, energy-dispersive X-ray, X-ray diffraction (XRD), and Brunauer-Emmett-Teller analyses. The results of XRD analysis implied that the prepared nanocomposite consists of two compounds of crystalline magnetite and amorphous IG, and the formation of its core/shell structure had been confirmed by TEM images. The catalytic performance of the as-prepared core/shell bionanocatalyst was evaluated for the first time in the synthesis of 1,4-dihydropyridine and 4 H -pyran derivatives under sonication in ethanol. This core/shell structure because of the superparamagnetic property of Fe 3 O 4 and unique properties of IG as a bifunctional biocatalyst offers a high potential for many catalytic applications. Recycling study revealed that no significant decrease in the catalytic activity was observed even after six runs.