NiFe2O4@SiO2-immobilized copper Schiff base complex as a versatile heterogeneous catalyst for efficient one-pot multicomponent synthesis of bioactive naphthopyran derivatives†

Abstract

Herein, we have presented the synthesis of a Cu(II) Schiff base metal complex immobilized on a silica-coated NiFe₂O₄ magnetic nanoparticle (MNP) surface, forming a novel heterogeneous and magnetically retrievable nanocatalyst, NiFe₂O₄@SiO₂@CuSB. Comprehensive characterization through FT-IR, PXRD, SEM, EDS, TEM, SAED, VSM, BET, and XPS confirms the catalyst's structure, surface morphology, elemental composition, and properties. Using a one-pot multicomponent synthesis of naphthopyran derivatives, the catalytic performance of NiFe₂O₄@SiO₂@CuSB was evaluated. This efficient, eco-friendly protocol enables the synthesis of naphthopyran derivatives using a diverse range of aldehydes, malononitrile, and 2-naphthol, exhibiting excellent functional group tolerance. The desired products have been synthesized in high yields without any byproducts. The heterogeneity of the solid nanocatalyst was assessed using a hot filtration test. This innovative catalyst offers a practical way to efficiently produce bioactive compounds, which have applications in medical chemistry.