Host-guest interactions in the confined spaces of metal–organic frameworks: Design principles, characterizations, and applications

Metal–organic frameworks (MOFs) are revolutionizing porous materials with their incredible structures and functionalities that have been extensively explored in many fields. Unlike traditional porous materials, MOFs offer a unique opportunity for precise design and modification of the porosities and pore environments. Their nanoscale confined spaces with specific shapes and surface functionalities can selectively interact with certain guest molecules through host-guest interactions, unlocking enhanced performance and related mechanisms that were previously undiscovered. Through advanced experimental and theoretical techniques, the high crystallinity of MOFs allows for detailed and in-depth studies of the structure-performance relationships, leading to breakthroughs in design and optimization. This review delves into recent advancements in the construction, characterization, and host-guest applications of MOF-based systems, showcasing their design strategies for remarkable functionality, porosity, and flexibility. The latest progress in adsorption, separation, catalysis, energy storage, crystalline sponge (CS), and sensing are discussed, unraveling the endless possibilities of MOFs and their challenges.