Expanding the Structural Topologies of Rare-Earth Porphyrinic Metal-Organic Frameworks through Ligand Modulation

Expanding the structural diversity of porphyrinic metal-organic frameworks (PMOFs) is essential to develop functional materials with novel properties or enhanced performance in different applications. Herein, we establish a strategy to construct rare-earth (RE) PMOFs with unprecedented topology via rational functionalization of porphyrinic ligands. By introducing phenyl/pyridyl groups to the meso-positions of the porphyrin core, the symmetries and connectivities of the ligands are tuned, and three RE-PMOFs (BUT-224/-225/-226) with new topologies are successfully obtained. In addition, BUT-225(Co), with both the Lewis basic and acidic sites, exhibits enhanced CO₂ uptake and higher catalytic activity for the cycloaddition of CO₂ and epoxides under mild conditions. This work reveals that the RE-PMOFs with novel topologies can be rationally designed and constructed through ligand functionalization, which provides insights into the construction of tailored PMOFs for various applications.