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首页> 外文期刊>Chemistry: A European journal >Influence of the Base on Pd@MIL-101-NH2(Cr) as Catalyst for the Suzuki-Miyaura Cross-Coupling Reaction
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Influence of the Base on Pd@MIL-101-NH2(Cr) as Catalyst for the Suzuki-Miyaura Cross-Coupling Reaction

机译：碱对Pd @ MIL-101-NH2（Cr）催化铃木-宫浦交叉偶联反应的影响

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摘要

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 N-2 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.
机译：金属有机骨架（MOF）的化学稳定性是阻止其在工业过程中使用的主要因素。在此表明，明智地选择Suzuki-Miyaura交叉偶联反应的碱可以避免MOF催化剂Pd @ MIL-101-NH2（Cr）的分解。比较了该反应的四个碱：K 2 CO 3，KF，Cs 2 CO 3和CsF。与氟化物相比，碳酸盐是最具活性的，并在较短的反应时间内获得了优异的收率。但是，粉末XRD和N-2吸附测量结果表明，当使用碳酸盐时，MOF催化剂会降解，但仍会结晶并带有氟化物。 XANES测量表明，降解的MOF中仍存在Pd @ MIL-101-NH2（Cr）的三聚体铬簇。另外，碱的不同抗衡阳离子显着影响材料的催化活性。 TEM显示，经过几次催化运行后，许多Pd纳米颗粒（NPs）已迁移到MOF颗粒的外表面并形成了较大的聚集体。与钾碱相比，用铯碱催化后的Pd NPs更大。

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