Pd-loaded superparamagnetic mesoporous NiFe₂O₄ as a highly active and magnetically separable catalyst for Suzuki and Heck reactions

A superparamagnetic solid catalyst has been successfully synthesized by loading palladium nanoparticles into the pore network of a mesoporous NiFe ₂O₄ support (Pd/NF300), which was used as a magnetically separable and highly active catalyst for Suzuki and Heck C-C coupling reactions. Various techniques were employed to characterize the synthesized NiFe ₂O₄ supports and Pd-loaded catalysts. The Pd/NF300 catalyst showed high activity for both Suzuki and Heck reactions even under a very low Pd using amount (0.08 mol% Pd based on aryl halide). Moreover, the catalyst could be magnetically separated, recycled, and showed a very slight reduction in catalytic activity after five cycles. A synergetic catalytic effect between the well dispersed Pd⁰ and the basic mesoporous structure of magnetic supports has been proposed to understand its greatly enhanced catalytic activities.