Post-synthetic modifications of metal–organic cages

Abstract

Metal–organic cages (MOCs) are discrete, supramolecular entities that consist of metal nodes and organic linkers, which can offer solution processability and high porosity. Thereby, their predesigned structures can undergo post-synthetic modifications (PSMs) to introduce new functional groups and properties by modifying the linker, metal node, pore or surface environment. This Review explores current PSM strategies used for MOCs, including covalent, coordination and noncovalent methods. The effects of newly introduced functional groups or generated complexes upon the PSMs of MOCs are also detailed, such as improving structural stability or endowing desired functionalities. The development of the aforementioned design principles has enabled systematic approaches for the development and characterization of families of MOCs and, thereby, provides insight into structure–function relationships that will guide future developments. Metal–organic cages with good solubility, accessible cavities and abundant reactive sites can undergo various post-synthetic modifications to assemble into multidimensional functional materials. This Review explores current post-synthetic modification strategies used for metal–organic cages, including covalent, coordination and noncovalent methods.