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BODIPY‐Based Photodynamic Agents for Exclusively Generating Superoxide Radical over Singlet Oxygen
Author(s) -
Teng KunXu,
Chen WenKai,
Niu LiYa,
Fang WeiHai,
Cui Ganglong,
Yang QingZheng
Publication year - 2021
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.202106748
Subject(s) - singlet oxygen , photochemistry , photodynamic therapy , bodipy , chemistry , trimer , singlet state , triplet state , reactive oxygen species , superoxide , oxygen , excited state , singlet fission , photosensitizer , molecule , fluorescence , organic chemistry , atomic physics , dimer , biochemistry , physics , enzyme , quantum mechanics
Developing Type‐I photosensitizers is considered as an efficient approach to overcome the deficiency of traditional photodynamic therapy (PDT) for hypoxic tumors. However, it remains a challenge to design photosensitizers for generating reactive oxygen species by the Type‐I process. Herein, we report a series of α,β‐linked BODIPY dimers and a trimer that exclusively generate superoxide radical (O 2 −. ) by the Type‐I process upon light irradiation. The triplet formation originates from an effective excited‐state relaxation from the initially populated singlet (S 1 ) to triplet (T 1 ) states via an intermediate triplet (T 2 ) state. The low reduction potential and ultralong lifetime of the T 1 state facilitate the efficient generation of O 2 −. by inter‐molecular charge transfer to molecular oxygen. The energy gap of T 1 ‐S 0 is smaller than that between 3 O 2 and 1 O 2 thereby precluding the generation of singlet oxygen by the Type‐II process. The trimer exhibits superior PDT performance under the hypoxic environment.