Steering Interpenetration and Charge Dynamics in MOFs via Metal Node Engineering for Photocatalytic Organic Transformations
Qu Bo, Hui Li, Mengyao She, Kexin Zhao, Ping Liu, Yaoyu Wang, Jianli Li
Abstract
Selecting metal nodes on the basis of their electronic configurations is crucial for enhancing the photocatalytic performance of Metal–organic frameworks (MOFs). However, regulation of the inherent structure–performance relationship of MOFs by rational selection of metal nodes remains largely unknown. To address this issue, two boron dipyrromethene (BODIPY)-based MOFs, Co-MOF and Zn-MOF, featuring identical ligands but distinct metal centers, were constructed. Replacing Zn(II) with Co(II) transforms the framework from a dense 3-fold interpenetrating structure to a more open 2-fold interpenetrating structure, which increases the pore size and solvent-accessible volume (25.6% vs 40.2%). Moreover, the 3d 7 electronic configuration of Co(II) facilitates rapid ligand-to-metal charge transfer (LMCT) and enhances photogenerated charge separation. Consequently, compared with the Zn-MOF, the Co-MOF demonstrates superior photocatalytic activity in both N-demethylation of tertiary amines and C-3 formylation of indoles. Particularly, this is the first time that MOFs based on BODIPY ligands have achieved photocatalytic conversion in these two organic reactions. This work discusses that the selection of metal nodes is a key factor in achieving the synergistic regulation of the structure and photoelectric properties of MOFs.