Metal–Organic Frameworks: Postsynthetic Modification

Abstract

Abstract Over the past 5 years or so, postsynthetic modification (PSM) has emerged as a powerful synthetic tool for preparing functionalized metal–organic frameworks (MOFs). In the simplest PSM protocols, a MOF is first prepared and then made to undergo a reaction to generate a new MOF. At its most useful, the new MOF is one that cannot be prepared by direct combination of metal and linker. In this review, three types of PSM reaction are considered. Covalent PSM is the most well‐established of these and involves a covalent modification of linker ligands. This can occur on addition of a reagent, or alternatively through thermal, photochemical, or electrochemical treatment. Dative PSM involves addition of a metal center to a vacant coordination site on a MOF, which is of interest for both catalysis and metal sequestration. Finally, inorganic PSM involves modification of the secondary building units (SBUs) in the MOF, or the coordination of these to the linkers. Inorganic PSM can involve substitution of labile terminal ligands, reaction at the anionic part of the SBU, a redox reaction or substitution of the framework metal centers, or substitution of the linker ligands.