Chemical Vapor Deposition of Pd(C3H5)(C5H5) to Synthesize Pd@MOF-5 Catalysts for Suzuki Coupling Reaction

Abstract

The highly porous metal organic framework MOF-5 was loaded with the metal–organic compound [Pd(C3H5)(C5H5)] by metal–organic chemical vapor deposition (MOCVD) method. The inclusion compound [Pd(C3H5)(C5H5)]@MOF-5 was characterized by powder X-ray diffraction (PXRD), Fourier-transform infrared (FT-IR) spectroscopy, and solid-state nuclear magnetic resonance spectroscopy. It was found that the host lattice of MOF-5 remained intact upon precursor insertion. The –C3H5 ligand in the precursor is easier to lose due to the interaction between palladium and the benzenedicarboxylate linker in MOF-5, providing a possible explanation for the irreversibility of the precursor adsorption. Pd nanoparticles of about 2–5 nm in size was formed inside the cavities of MOF-5 by hydrogenolysis of the inclusion compound [Pd(C3H5)(C5H5)]@MOF-5 at room temperature. N2 sorption of the obtained material confirmed that high surface area was retained. In the Suzuki coupling reaction the Pd@MOF-5 materials showed a good activity in the first catalytic run. However, the crystal structure of MOF-5 was completely destroyed during the following reaction runs, as confirmed by PXRD, which caused a big loss of the activity. The embedding of palladium nanoparticles into the metal organic framework MOF-5 has been successfully prepared by MOCVD method, and been used as catalyst for Suzuki reaction. The prepared Pd@MOF-5 had a very high BET surface area with Pd particles in size of 2–5 nm. The Pd@MOF-5 was used as a heterogeneous catalyst for the Suzuki coupling reaction and achieved a good activity.