Sustainable fabrication of NiCuFe2O4 nanospheres: a highly effective palladium-free heterogeneous catalyst for biaryl scaffold synthesis via a Suzuki–Miyaura cross-coupling reaction†

In this work, a noble metal-free and recyclable NiCuFe₂O₄ nanoparticle was developed via a one-pot co-precipitation approach. The synthesized nanoparticle was characterized by various sophisticated techniques such as SEM, EDX, VSM, PXRD, XPS, BET, ICP-AES, ICP-MS, elemental mapping and TEM analyses to gain detailed insights about its physiochemical properties. Electron microscopy studies validate the formation of hierarchical nanosphere morphology of the as-synthesized NiCuFe₂O₄ nanoparticles, while VSM analysis highlights their ferromagnetic nature. Powder X-ray diffraction reveals that Cu replaces Ni in the face-centered cubic lattice, causing a shift in peak positions as well as an increase in the lattice parameter with reduced Ni content. This cost-effective and magnetically separable NiCuFe₂O₄ nanostructure holds promise as a potential substitute for Pd-based catalysts in Suzuki–Miyaura cross-coupling of arylboronic acid with various substituents of aryl halide. Notably, they demonstrate remarkable catalytic activity in producing biaryl scaffolds by effectively activating not only Ar–Br bonds but also chemically inert Ar–Cl and Ar–F bonds under mild conditions in ethanol–water media, outperforming most of the reported works involving transition metal-based catalysts. These heterogenous catalysts have the tendency to retain their activity up to the fifth iterations during the reaction with a broad substrate scope, providing significant economic advantages for industrial applications.