Recyclable palladium(II) imino-pyridine complex immobilized on mesoporous silica as a highly active and recoverable catalyst for Suzuki-Miyaura coupling reactions in aqueous medium

A new mesoporous silica supported palladium imino-pyridine complex was successfully prepared by attaching palladium acetates to a novel imino-pyridine ligand functionalized MCM-41. The as-prepared catalyst was characterized by ICP-AES, XRD, FTIR, SEM, and TEM. It was found to be an efficient catalyst for Suzuki-Miyaura coupling reactions in aqueous medium. The reactions of various aryl bromides with arylboronic acids could be carried out under aerobic and low Pd loading (0.1 mol %) conditions with good to excellent yields, and very low Pd leaching (<0.2 ppm) was detected. Moreover, the supported catalyst could be simply recovered and reused several times without significant loss of efficiency.