C–N Coupling Reaction Assisted by a Highly Effective Porous Nanocomposite as a Stable and Innovative Magnetic Catalyst

Efficient and recyclable catalytic systems for carbon–nitrogen (C–N) bond formation remain a key challenge in green organic synthesis. Here, a novel magnetic Fe3O4@ZIF-8-Cu nanocatalyst was synthesized and fully characterized. Detailed structural studies established that a core–shell composite with a high surface area, large porosity, uniform copper dispersion, and good magnetic properties, which enables quick recovery, was successfully prepared. The catalyst exhibited high efficiency in the synthesis of diaryl guanidines with yields up to 95% under mild conditions. Notably, the catalyst retains its structure and catalytic performance in repeated reactions. Overall, this article presents an efficient, magnetically separable, and greener catalytic platform for the production of diaryl guanidines, which serve as useful scaffolds in organic pharmaceutical and synthetic chemistry. The complementary properties of the magnetic core, porous shell, and available copper active sites make Fe3O4@ZIF-8-Cu a promising alternative to conventional homogeneous copper catalysts.