Chemical Vapor Deposition of Pd(C 3 H 5 )(C 5 H 5 ) to Synthesize Pd@MOF-5 Catalysts for Suzuki Coupling Reaction
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Chemical Vapor Deposition of Pd(C3H5)(C5H5) to Synthesize Pd@MOF-5 Catalysts for Suzuki Coupling Reaction Mingming Zhang • Jingchao Guan • Bingsen Zhang • Dangsheng Su • Christopher T. Williams • Changhai Liang
Received: 18 November 2011 / Accepted: 7 January 2012 / Published online: 19 January 2012 Ó Springer Science+Business Media, LLC 2012
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 (FTIR) 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. M. Zhang J. Guan C. Liang (&) Laboratory of Advanced Materials and Catalytic Engineering, Dalian University of Technology, Dalian 116024, China e-mail: [email protected] URL: http://finechem.dlut.edu.cn/liangchanghai B. Zhang D. Su Department of Inorganic Chemistry, Fritz Haber Institute of the Max Planck Society, 14195 Berlin, Germany C. T. Williams Department of Chemical Engineering, University of South Carolina, Columbia, SC 29208, USA
Keywords MOF-5 Palladium MOCVD Suzuki coupling
1 Introduction Recently, there has been a considerable upsurge in the study of porous hybrid organic–inorganic materials-metal organic frameworks, referred to as MOFs. Because of their tunable cavities, high surface area, controlled porosity and low density, MOFs have been applied in a lot of fields including chemical sensing [1, 2], drug release [3], gas sorption or storage [4], and catalysis [5]. However, their application in catalysis has been very limited mainly due to two factors: first, the stability of the materials toward temperature, moisture, and some reactants and impurities is much lower compared to inorganic porous materials; second, in many MOF structures, the coordination positions around the metal ion are occupied by organic linkers, leaving no available place for reactants sorption [6–8]. However, as an alternative concept, MOF can be used as a catalyst support and applied in fine chemical synthesis. Opelt et al. [9] prepared a 0.5 wt% Pd@MOF-5 catalyst by the coprecipita
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