Synergistic Enhancement of Ligand & Cluster Connectivity to Construct Highly Stable Fluorescein-Based MOFs with Thickened Channel Walls for Boosting Photocatalytic Activity

Fabricating visible-light-responsive metal−organic frameworks (MOFs) with high stability and effective catalytic functionality remains a long-term pursuit yet a great challenge. Herein, a strategy of increasing ligand and cluster connectivity is developed to construct highly stable fluorescein MOFs, La-CFL, presenting a new (4,8)-connected topological structure compared to Cd-FL constructed using 6-connected dinuclear clusters and 3-connected tritopic ligands. La₈(CFL)₄ containers like Chinese “Ritual Wine Vessels (Jue)” resemble linear arrangements interconnected by the [La₂(COO)₄] clusters. This arrangement induces benzene rings and xanthene rings to locate on the inner walls of 1D channels, resulting in thicker channel walls that contribute to enhanced stability. Consequently, La-CFL demonstrates outstanding catalytic performance in thiol–ene reactions under green LED irradiation. It exhibits 2.3 times higher efficiency than Cd-FL while reducing reaction time to one-fifth at 20 min. Furthermore, La-CFL displays size-selective catalysis and retains full activity for 20 cycles without degradation, an improvement over Cd-FL's recyclability limitations.