Metal-organic frameworks based materials as heterogeneous catalysts for C-H bond activation.

Converting light hydrocarbons, such as methane, ethane, propane, and cyclohexane into value-added chemicals and fuel products by direct C-H functionalization is an attractive method in the petrochemical industry. Emerging as a relatively new class of porous solid materials, metal-organic frameworks (MOFs) are appealing as single-site heterogeneous catalysts or catalyst supports for C-H bond activation. In contrast to the traditional microporous and mesoporous materials, MOFs feature high porosity, versatile structural and functional tunability, and molecular level characterization of the structures for the study of structure-property relationships. These virtues endow MOFs as ideal platforms to develop catalysts for C-H activation with high catalytic activity, selectivity and recyclability under relatively mild reaction conditions. This review highlights the research aimed at the implementation of MOFs as sing-site heterogeneous catalysts for C-H bond activation. It provides insights into the rational design and synthesis of three types of stable MOF catalysts for C-H bond activation, that is, (i) metal nodes as catalytic sites, (ii) incorporation of catalytic sites into organic struts, and (iii) incorporation of catalytically active guest species into pores of MOFs. Here, the rational design and synthesis of MOF catalysts that lead to the distinct catalytic property for C-H bond activation are discussed, along with the post-synthesis of MOFs, intriguing functions with MOF catalysts and microenvironments that lead to the distinct catalytic properties of MOF catalysts.