A new Pd(II) catalyst supported on magnetic SBA-15 for the Mizoroki-Heck coupling reaction

This study details the anchoring of a linear polyamine-Pd(II) complex on magnetite/SBA-15 composite. The synthesis involved sequential treatment of magnetic mesoporous silica with (3-aminopropyl) triethoxysilane (APTES), trichlorotriazine, tetraethylenepentamine (TEPA), PdCl₂, and sodium acetate, resulting in the formation of Fe₃O₄@SBA-TEPA-Pd(II). The supported complex was thoroughly characterized using standard analytical techniques. X-ray photoelectron spectroscopy (XPS) further confirmed the presence of both Pd(II) and Pd(0) species within the material. The catalytic activity of Fe₃O₄@SBA-TEPA-Pd(II) was systematically investigated in the Mizoroki-Heck cross-coupling reaction, with a detailed examination of the influences of various reaction parameters. The reaction was optimized using N-methylpyrrolidone (NMP) as the solvent, a 0.36 mol % Pd catalyst, K₂CO₃ as the base, and a reaction temperature of 120 °C. Under these conditions, the Fe₃O₄@SBA-TEPA-Pd(II) catalyst exhibited a broad substrate scope, efficiently reacting with a range of haloarenes (I, Br, Cl) and olefins. The catalyst demonstrated several practical benefits, including facile magnetic separation, high stability, recyclability over six cycles, and minimal palladium leaching of 0.1 %.