Among porous materials, metal-organic frameworks (MOFs) take the lead in heterogeneous support catalysts because the structure of MOFs can be readily tuned by choice of metal and organic building blocks, and further be modified with diverse functional groups. In order to immobilize catalytically active metal sites on MOFs and efficiently utilize them, it would be essential to employ the coordinating functionalities to the pores and frameworks, which can anchor the metal sites with high stability and control the reactivity of the catalytic centres. However, in order not to obtain the unwanted structures by participation of additional coordinating groups in the framework construction of MOFs, the pore engineering with coordinating functionalities should be carefully implemented. In this review, we discuss various strategies of pore engineering to impart catalytic activities to the MOF architectures, classifying them into two approaches: pre-integrated ligand and sequential attachment. The former demonstrates the use of organic ligands that are already capable of possessing catalytic sites, and the ligands can directly integrate the metals before or after the production of the MOFs. The other approach is the post-synthetic attachment of coordinating functionalities through the sequential attachment process, in which immobilization of catalytically active metal sites also can be achieved by both pre-and post-metalation. Finally, this review will comprehensively discuss the representative catalytic reactions of MOF-based heterogeneous catalysts.

Metal–organic frameworks (MOFs) are an attractive catalyst support for stable immobilization of the active sites in their scaffold due to the high tunability of organic ligands. The active site‐functionalized ligands can be easily employed to construct MOFs as porous heterogeneous catalysts. However, the existence of active sites on the external surfaces as well as internal pores of MOFs seriously impedes the selective reaction in the pore. Herein, through a simple post‐synthetic ligand exchange (PSE) method we synthesized surface‐deactivated (only core‐active) core–shell‐type MOF catalysts, which contain 2,2,6,6‐tetramethylpiperidin‐1‐yl)oxyl (TEMPO) groups on the ligand as active sites for aerobic oxidation of alcohols. The porous but catalytically inactive shell ensured the size‐selective permeability by sieving effects and induced all reactions to take place in the pores of the catalytically active core. Because PSE is a facile and universal approach, this can be rapidly applied to a variety of MOF‐based catalysts for enhancing reaction selectivity.

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