High-performance NiFe2O4 spinel catalysts: Recyclability and efficiency in multicomponent reactions

Abstract

Multicomponent reactions (MCRs) provide a greener approach to chemical synthesis, yet their complexity requires efficient catalysts. In this study, we investigate nickel ferrite spinels (NiFe₂O₄) as heterogeneous catalysts for the aza-Henry MCR to synthesize 2-arylimidazo[1,2-a]pyridines. NiFe₂O₄ was synthesized via a sol–gel method and calcined at 500, 700, and 1000 °C. Higher calcination temperatures yielded spinels with enhanced purity, crystallinity, and magnetization, improving catalytic performance, particularly for the sample calcined at 1000 °C. Catalytic assays showed that with just 10 mol.% catalyst, the yield of 2-arylimidazo[1,2-a]pyridine reached 93 %, surpassing both homogeneous and heterogeneous alternatives. NiFe₂O₄ also efficiently catalyzed the synthesis of the gastroprotective drug Zolimidine®, achieving a 65 % yield. Its magnetic properties facilitated easy recovery and reuse over five cycles, maintaining 80 % catalytic efficiency and over 98 % recovery. These results highlight NiFe₂O₄ spinels as sustainable, recyclable, and highly effective catalysts for MCRs, making them promising candidates for laboratory and industrial applications.