Palladium-supported Fe3O4@SiO2 functionalized methyl 2-phenyl thioacetate as a sustainable catalyst for Isatins synthesis

The researchers have actively developed sustainable catalysis processes, placing a strong emphasis on heterogeneous catalysts to reduce the use of toxic solvents and reagents, as well as to mitigate hazardous reactions and streamline time-consuming separations, over the past two decades. Preserving active sites has become a critical focus area during this period. This study centered on synthesizing and evaluating Fe₃O₄@SiO₂-SD@Pd, assessing its efficacy and reusability. A comprehensive suite of characterization techniques was employed, including FT-IR, TGA, FE-SEM, VSM, TEM, BET, ICP, EDS, mapping, and XRD. The results demonstrate that Fe₃O₄@SiO₂-SD@Pd is effective for both Isatin Heck, C-H activation, and cycloaddition reactions under moderate conditions, yielding between 78% and 88%. Notably, this catalyst exhibits simultaneous activity in both reactions within a DMF-H₂O solvent mixture at lower temperatures. The mercury poisoning test confirmed that the reaction proceeds via the Pd ⁽⁰⁾/Pd ⁽⁺²⁾ mechanism. Furthermore, the catalyst is environmentally benign and retains its efficiency over five reuse cycles without significant loss.