Recyclable Pd(II) immobilized MCM-41 based heterogeneous catalyst for Suzuki-Miyaura and Heck coupling reactions

A new palladium(II) immobilized MCM-41 based catalyst Pd(II)-MS2 was prepared via a facile and straightforward post -modification method. Initially, 3-(trimethoxysilyl)propane-1-thiol was incorporated into the mesoporous matrix MCM-41 to produce SH-propylsilyl@MCM-41 ( MS1 ), which on treatment with an amide -based ligand ( L 1 ) yielded a periodic mesoporous silica material L 1 -S-propylsilyl@MCM-41( MS2 ) having suitable binding sites where Pd(II) ion can easily accumulate. The resulting material MS2 on treatment with Pd(OAc) 2 produces the desired mesoporous material Pd(II)-L 1 -S-propylsilyl@MCM-41 ( Pd(II)-MS2 ) under reflux reaction condition in MeCN. The synthesized mesoporous materials were successfully characterized by various spectroscopic techniques and analyses such as FT-IR, TGA, XPS, TEM, UV-Vis, PXRD, ICP, N 2 adsorption-desorption isotherm. The synthesized mesoporous material Pd(II)-MS2 was used as an efficient and recyclable solid catalyst for Suzuki-Miyaura and Heck coupling reaction under mild reaction conditions. Further, the resulting catalyst can be easily separated from the reaction mixture by simple filtration and efficiently reused up to seven consecutive catalytic cycles for both Suzuki and Heck coupling reactions without loss of catalytic activity. Importantly, synthesized catalyst Pd(II)-MS2 shows excellent catalytic activity even for less reactive aryl chlorides with a decent substrate conversion up to 73-100% yield.