Study on Periodic Mesoporous Rh(I) Organometallic Catalyst for Water-medium Heck Reaction

Periodic mesoporous Rh(I) organometallic catalyst[Rh(I)-PPh2-PMO(Ph)] was synthesized by coordinating Rh (PPh3)(3) Cl complex with PPh2-ligand originally incorporated into the phenyl-bridged periodic mesoporous organosilica(PMO) via surfactant-directed co-condensation approach. The Rh(I) heterogeneous catalyst were characterized by FTIR, NMR, XRD, TEM and N-2 sorption technologies. This catalyst can be effectively applied in water-medium Heck reaction, which results demonstrated it afforded similar catalytic performance to that of the corresponding homogeneous catalyst. It could be attributed to the large surface area and ordered mesoporous channels of the PMOs support, leading to the high dispersion of Rh(I) active sites and the reduced diffusion limit. Meanwhile, the phenyl 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 Rh(I)-PPh2-PMO(Ph) could be used repetitively, showing a good potential in industrial applications.