Ordered mesoporous organometallic catalyst Pd(II)-PPh₂-PMO(Et) was synthesized by coordinating the Pd(II) with PPh₂-ligand originally incorporated into the ethyl-bridged periodic mesoporous organosilica via surfactant-directed co-condensation. This catalyst exhibited matchable activity with the corresponding PdCl₂(PPh₃)₂ homogeneous catalyst in water-medium Barbier reaction. On one hand, it could be attributed to the large surface area and ordered mesporous channels of the PMO support, leading to the high dispersion of Pd(II) active sites and the reduced diffusion limit. Meanwhile, the ethyl fragments embedded in the pore walls could enhance surface hydrophobility, which further promoted the diffusion and adsorption of organic molecules, leading to the enhanced activity. Besides, the Pd(II)-PPh₂-PMO(Et) could be used repetitively, showing a good potential in industrial applications.

Key words: periodic mesoporous organosilica, Pd(PPh₃)₂Cl₂, immobilized homogeneous catalyst, Barbier reaction, water-medium clean organic reaction