Fe3O4@SiO2@ILâPVP magnetic nanoparticles: Effective synthesis of spirooxindoles

Abstract

Various magnetite heterogeneous catalysts for the organic reaction are increasingly recognized while their stability still is a critical challenge. In this regard, SiO₂, ionic liquid (IL), and polyvinyl pyrrolidone (PVP) were applied as a three-layer stabilization system for modifying magnetic Fe₃O₄ to produce Fe₃O₄@SiO₂@ILâPVP as a novel nanocatalyst. The Fe₃O₄@SiO₂@ILâPVP as stabilized heterogeneous catalysts were utilized in a robust, and environmentally friendly strategy for the preparation of the spirooxindole derivatives by the one-pot condensation of isatin, malononitrile, and 1,3-dicarbonyl in a water solvent. The proposed method revealed a high yield spirooxindole derivatives preparation (99%) at short reaction times (1.0 min), low catalyst mass (0.002 g), and satisfactory temperature (30 °C) which confirm the lack of any tedious challenge and promising applicability and reusability. This work introduces a rational core-shell nanosystem design with a facile and novel construction strategy to arrive at nonexquisite metal-based composite catalysts with superior catalytic proficiency and prominent long-term stability.