Influence of the Base on Pd@MIL‐101‐NH2(Cr) as Catalyst for the Suzuki–Miyaura Cross‐Coupling Reaction |
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| Authors: | Dr. Fabian Carson Vlad Pascanu Dr. Antonio Bermejo Gómez Yi Zhang Dr. Ana E. Platero‐Prats Prof. Xiaodong Zou Prof. Belén Martín‐Matute |
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| Affiliation: | 1. Berzelii Center EXSELENT on Porous Materials, Stockholm University, 106?91 Stockholm (Sweden);2. Department of Materials and Environmental Chemistry, Stockholm University, 106 91 Stockholm (Sweden);3. Department of Organic Chemistry, Stockholm University, 106 91 Stockholm (Sweden);4. Current Address: AstraZeneca Translational Science Centre at Karolinska Institute, Stockholm, 171 65 (Sweden) |
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| Abstract: | The chemical stability of metal–organic frameworks (MOFs) is a major factor preventing their use in industrial processes. Herein, it is shown that judicious choice of the base for the Suzuki–Miyaura cross‐coupling reaction can avoid decomposition of the MOF catalyst Pd@MIL‐101‐NH2(Cr). Four bases were compared for the reaction: K2CO3, KF, Cs2CO3 and CsF. The carbonates were the most active and achieved excellent yields in shorter reaction times than the fluorides. However, powder XRD and N2 sorption measurements showed that the MOF catalyst was degraded when carbonates were used but remained crystalline and porous with the fluorides. XANES measurements revealed that the trimeric chromium cluster of Pd@MIL‐101‐NH2(Cr) is still present in the degraded MOF. In addition, the different countercations of the base significantly affected the catalytic activity of the material. TEM revealed that after several catalytic runs many of the Pd nanoparticles (NPs) had migrated to the external surface of the MOF particles and formed larger aggregates. The Pd NPs were larger after catalysis with caesium bases compared to potassium bases. |
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| Keywords: | cross‐coupling heterogeneous catalysis metal– organic frameworks nanoparticles palladium |
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