Enhancing H₂ Uptake by “Close‐Packing” Alignment of Open Copper Sites in Metal–Organic Frameworks

Open and close: Inspired by close-packing of spheres, to strengthen the framework–H2 interaction in MOFs (metal-organic frameworks), a strategy is devised to increase the number of nearest neighboring open metal sites of each H2-hosting cage, and to align the open metal sites toward the H2 molecules. Two MOF polymorphs were made, one exhibiting a record high hydrogen uptake of 3.0 wt % at 1 bar and 77 K.