Enhanced Activity of MOF-Based Pd/Electron-Transfer Mediator Catalysts in Oxidation Reactions Involving Isonitrile by Defect Engineering

Herein, we report a Pd/electron-transfer mediator (ETM) catalyst "Pd/Cu-UiO-67(N)x" based on defect-engineered metal–organic frameworks (MOFs), which exhibits high activity and stability in the aminoamidation reaction of N-sulfonyl-2-allyl aniline with isonitrile insertion. The Pd turnover number of the Pd/Cu-UiO-67(N)x system is about 30 times higher than that of existing catalytic systems by decreasing the loading of Pd and base. This work systematically investigates the specific effects of defects on the activation of the reactants. The rationally anchored Pd(II) and Cu(II) in the framework interact with the O2 trapped in the defective MOF to achieve reoxidation of Pd(0). This strategy not only confers high activity and stability to Pd(II) species but also provides access to the application of MOFs in large-size substrate transformations.