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Metal-Organic Frameworks Through Cavity Design

Metal-Organic Frameworks (MOFs) have attracted worldwide research efforts because of their fascinating structures and intriguing potential applications in clean energy, especially in gas storage and carbon capture. Synthetically, a one-pot reaction between a metal salt and an organic linker has dominated the field. This approach appears simple but the reactions happened during the procedure are complicated. To study the mechanism of MOF assembly and to gain more control in MOF synthesis, we launched a cavity-by-cavity approach. In this presentation, I will start with a single cavity (the enclosure of a Metal-Organic Polyhedron or MOP), and show that the “bridging angle” of a ligand determines the geometry of the cavity. I will demonstrate that bridging-ligand substitution reaction can be generally applied in both MOP and MOF preparation. From there, I’ll show that single cavities can be assembled into chains and 2D or 3D networks of cavities either by step-wise assembly or ligand design and extension. These synthetic methods have lead to novel MOFs such as “single-molecule traps” and “elastic single-molecule traps” for carbon capture. MOFs with unusual stability will also be presented. At the end, a biomimetic MOF built from 1D cavities (channels) that exhibits enzymatic functions will be discussed.