Water-Medium Barbier Reaction over a Mesoporous Pd(II) Organometallic Catalyst Immobilized on the Ethyl-Bridged PMOs

Abstract

A mesoporous Pd(II) organometallic catalyst is synthesized by coordinating the Pd(II) with the amine-ligand anchored on ethyl-bridged PMOs. During Barbier reaction in water as an environmentally friendly medium, the as-prepared Pd(II)-PMOs (Et) exhibits matchable catalytic activity and selectivity with the corresponding homogeneous Pd(II) catalyst and could be used repetitively for more than 5 times, which could reduce the cost and even diminish the environmental pollution from heavy metallic ions, showing a good potential in industrial applications. On one hand, the excellent catalytic performance could be attributed to the high surface area and ordered mesporous structure of the PMOs support, which ensures the higher dispersion of Pd(II) active sites and also facilitates the diffusion of reactant molecules. On the other hand, the ethyl fragments embedded in the pore walls could enlarge mesopores and also enhance surface hydrophobility of the PMOs support, which further promotes the diffusion and adsorption of organic molecules, especially in aqueous medium, leading to higher activity and selectivity.