Halogenated BODIPY photosensitizers: Photophysical processes for generation of excited triplet state, excited singlet state and singlet oxygen

Hu，Wenbin1; Zhang，Rui1; Zhang，Xian Fu2; Liu，Jiatian1; Luo，Lin1

2022-05-05

10.1016/j.saa.2022.120965

SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY   影响因子和分区

1386-1425

1873-3557

We have systematically examined the formation of singlet oxygen O(Δ), the excited triplet state (T), and excited singlet state (S) for halogenated BODIPY photosensitizers (halogen = Cl, Br, and I) in eight solvents to understand how halogen atoms and solvent affect these properties. The phosphorescence spectra and lifetimes of singlet oxygen generated by these halogenated BODIPYs have been measured by steady state/time resolved NIR emission, while the formation quantum yield of singlet oxygen (Φ) has been determined by chemical method using diphenylisobenzofuran (DPBF) as the trapping agent. The formation quantum yield Φ of singlet oxygen can be as high as 0.96 for iodinated BODIPY and 0.71 for brominated BODIPY. The triplet state T absorption spectra of brominated and iodinated BODIPYs have been recorded by laser flash photolysis method, in which T shows high formation efficiency and long lifetime. The formation and decay of excited singlet state S of four BODIPYs have been measured by ground state (S) absorption and steady state/time resolved fluorescence. The results show that larger halogen atoms on BODIPY core lead to smaller fluorescence quantum yield, shorter fluorescence lifetime and higher singlet oxygen formation quantum yield due to heavy atom effect that promotes the formation of triplet state. On the other hand, higher solvent polarity causes lower singlet oxygen formation quantum yield, smaller fluorescence quantum yield, and shorter fluorescence lifetime. This solvent effect is explained by the presence of photoinduced charge transfer (ICT) process from halogen atoms to BODIPY. The ICT efficiency has been estimated and the results are agreed with ICT theory. ICT process in halogenated BODIPYs has never been revealed in literature. HOMO/LUMO obtained from DFT calculation also supports the presence of ICT. The involvement of ICT in the photosensitizing process of halogenated BODIPYs provides new insights for designing BODIPY photosensitizers for photodynamic therapy of tumor.

Boron dipyrromethene Fluorescence Heavy atom effect Singlet oxygen Triplet-triplet absorption

SCI ; EI

英语

其他

National Natural Science Foundation of China[62074073] ; Natural Science Foundation of Shenzhen City[JCYJ20190809154005668] ; Multidisciplinary Program in Petrochemistry and Polymer Science, Faculty of Science, Chulalongkorn University[KCJSX2021071]

Spectroscopy

Spectroscopy

WOS:000792688400004

PERGAMON-ELSEVIER SCIENCE LTD

20220611596086

Atoms ; Boron ; Charge transfer ; Dies ; Efficiency ; Excited states ; Ground state ; Halogenation ; Oxygen ; Photodynamic therapy ; Photolysis ; Photosensitizers ; Quantum theory ; Quantum yield ; Solvents

Medicine and Pharmacology:461.6 ; Foundries:534.1 ; Nonferrous Metals and Alloys excluding Alkali and Alkaline Earth Metals:549.3 ; Machine Tool Accessories:603.2 ; Light/Optics:741.1 ; Physical Chemistry:801.4 ; Chemical Reactions:802.2 ; Chemical Agents and Basic Industrial Chemicals:803 ; Chemical Products Generally:804 ; Production Engineering:913.1 ; Atomic and Molecular Physics:931.3 ; Quantum Theory; Quantum Mechanics:931.4

CHEMISTRY

2-s2.0-85124026264

Scopus

1.Department of Chemical Engineering,Hebei Normal University of Science and Technology,Qinhuangdao,066004,China
2.Department of Materials Science and Engineering,Southern University of Science and Technology,Shenzhen,518055,China

Hu，Wenbin,Zhang，Rui,Zhang，Xian Fu,et al. Halogenated BODIPY photosensitizers: Photophysical processes for generation of excited triplet state, excited singlet state and singlet oxygen[J]. SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY,2022,272.

Hu，Wenbin,Zhang，Rui,Zhang，Xian Fu,Liu，Jiatian,&Luo，Lin.(2022).Halogenated BODIPY photosensitizers: Photophysical processes for generation of excited triplet state, excited singlet state and singlet oxygen.SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY,272.

Hu，Wenbin,et al."Halogenated BODIPY photosensitizers: Photophysical processes for generation of excited triplet state, excited singlet state and singlet oxygen".SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 272(2022).