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Influence of the Base on Pd@MIL‐101‐NH 2 (Cr) as Catalyst for the Suzuki–Miyaura Cross‐Coupling Reaction
Author(s) -
Carson Fabian,
Pascanu Vlad,
Bermejo Gómez Antonio,
Zhang Yi,
PlateroPrats Ana E.,
Zou Xiaodong,
MartínMatute Belén
Publication year - 2015
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201500843
Subject(s) - catalysis , sorption , base (topology) , chemistry , decomposition , chromium , coupling reaction , nanoparticle , xanes , inorganic chemistry , caesium , potassium , metal , chemical engineering , materials science , organic chemistry , nanotechnology , adsorption , mathematical analysis , physics , mathematics , quantum mechanics , spectroscopy , engineering
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‐NH 2 (Cr). Four bases were compared for the reaction: K 2 CO 3 , KF, Cs 2 CO 3 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‐NH 2 (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.