BODIPY photosensitizers based on PET and heavy atom effect: A comparative study on the efficient formation of excited triplet state and singlet oxygen in BODIPY dimers and monomers

作者：Zhang, Xian-Fu^*

来源：Journal of Photochemistry and Photobiology A: Chemistry , 2018, 355: 431-443.

DOI：10.1016/j.jphotochem.2017.07.019

• Singlet oxygen
• Photosensitizer
• Excited triplet state
• Photoinduced electron transfer
• BODIPY dimer
• Charge recombination

Covalent dimerization and iodine substitution methods were used to synthesize heavy atom free and heavy atom present BODIPY singlet oxygen photosensitizers. Both dimerization and iodization could strongly enhance the excited triplet state (T-1) formation up to 95% efficiency. The mechanism for excited triplet state formation was revealed by examining UV-vis electronic absorption, steady state and time resolved visible and NIR luminescence, laser flash photolysis, singlet oxygen chemical trapping, and quantum chemical calculation. The dimerization method shows a different mechanism in T-1 generation: photoinduced electron transfer (PET) from lowest lying excited singlet state (S-1) followed by charge recombination, instead of the traditional intersystem crossing from Si state. The PET mechanism makes such a photosensitizer sensitive to solvent polarity. This type of heavy atom free and PET-based photosensitizers could be important in photodynamic therapy of tumor and organic photochemistry.

• 出版日期2018-3-15
• 单位河北科技师范学院