Identifying the Key Photosensitizing Factors over Metal–Organic Frameworks for Selective Control of 1 O 2 and O 2 ⋅ − Generation

Abstract The reaction pathway, product selectivity and catalytic efficiency of photo‐oxidation are highly dependent on the specific reactive oxygen species (ROS), such as singlet oxygen ( 1 O 2 ) and superoxide (O 2 ⋅ − ), generated via the sensitization of O 2 by photosensitizers. Studies on uncovering the role of photosensitizing factors on the selective control of 1 O 2 and O 2 ⋅ − generation are significant but remain underexplored. Here, we constructed a photosensitizing metal–organic framework molecular platform (UiO‐1–UiO‐4) by elaborately engineering Ir(III) complex ligands with pyrenyl group for modulating photosensitizing factors and elucidating their impact on ROS generation. Impressively, the ratios of 1 O 2 and O 2 ⋅ − generation varied from 0 : 100 for UiO‐1 to 94 : 6 for UiO‐4 by modulating photosensitizing factors. UiO‐2 and UiO‐4 were respectively immobilized in a continuous‐flow reactor, achieving gram‐scale photosynthesis of phenol and juglone with high purity (>94 %) via O 2 ⋅ − and 1 O 2 pathway, respectively. Investigations reveal that UiO‐4 with ligand localized excited state and long excited state lifetime contributed to triggering energy transfer to afford 1 O 2 , whereas UiO‐1 with charge‐transfer state and negative reduction potential facilitates charge transfer to produce O 2 ⋅ − . This work offers a novel insight into regulating ROS generation by modulating the photosensitizing factors at the molecular level.