Palladium nanoparticles encapsulated inside the pores of a metal–organic framework as a highly active catalyst for carbon–carbon cross-coupling

Abstract

Well dispersed palladium nanoparticles were successfully encapsulated in the cages of a metal–organic framework, MIL-101, by using a “double solvents” method coupled with subsequent reduction with NaBH₄. Such a fabrication method can effectively avoid the aggregation of palladium nanoparticles on the external surfaces of MIL-101. The as-prepared catalyst, Pd@MIL-101, was characterized by transmission electron microscopy, powder X-ray diffraction, X-ray photoelectron spectroscopy, N₂ adsorption and inductively coupled plasma atomic emission spectroscopy. The Pd@MIL-101 composite exhibited high catalytic activity toward the Suzuki–Miyaura and Heck cross-coupling reactions. The catalyst can be readily recovered and reused in at least 5 consecutive cycles without significant loss its catalytic activity.