Topology Exploration in Highly Connected Rare-Earth Metal–Organic Frameworks via Continuous Hindrance Control

The structural diversity of highly connected metal–organic frameworks (MOFs) has long been limited due to the scarcity of highly connected metal clusters and the corresponding available topology. Herein, we deliberately chose a series of tritopic linkers with multiple substituents to construct a series of highly connected rare-earth (RE) MOFs. The steric hindrance of these substituents can be systematically tuned to generate various linker rotamers with tunable configurations and symmetries. For example, the methyl-functionalized linker (L-CH3) with C2v symmetry exhibits larger steric hindrance, forcing two peripheral phenyl rings perpendicular to the central one. The combination of C2v linkers and 9-connected RE6 clusters leads to the formation of a new fascinating (3,9)-c sep topology. Unlike Zr-MOFs exhibiting Zr6 clusters in various linker configurations and corresponding different structures, the adaptable RE6 clusters can undergo metal insertion and rearrange into new RE9 clusters when connected to ...