Metal-Mode-Controlled Ligand-to-Metal Charge Transfer in Isostructural One-Dimensional BODIPY MOFs and Photocatalytic H2O2 Production

Abstract

One-dimensional (1D) MOFs offer spatially confined pathways for rapid charge migration, minimizing the transport dispersion and junction resistance typical of multidirectional networks. This structural anisotropy offers an ideal platform for elucidating how distinct metal nodes and photoactive ligands modulate excited-state dynamics in photoactive MOFs. However, the active role of metal nodes as electronic modulators, rather than passive connectors, in chromophore-based 1D MOFs is yet to be elucidated. Herein, two isostructural boron-dipyrromethene (BODIPY)-based Co-MOF and Cd-MOF were designed and synthesized as a defined platform to decouple the influence of framework topology from that of metal-node electronics and to elucidate metal-controlled ligand-to-metal charge transfer (LMCT) in photoexcited electronic evolution. Photocatalytic performance reveals that Co-MOF exhibits substantially improved visible-light-driven two-electron oxygen reduction to H2O2, delivering a production rate of 702 μmol g–1 h–1, compared with 380 μmol g–1 h–1 for Cd-MOF. Spectroscopic and electrochemical spectra demonstrate that the open-shell Co2+ nodes strengthen electronic coupling, promoting efficient LMCT and charge separation with BODIPY linkers. In contrast, the closed-shell Cd2+ nodes lack the ability to undergo rapid electron transfer. This work establishes metal nodes as active participants in photoinduced charge evolution and develops a design principle for developing high-performance photoactive 1D MOFs.