BODIPY parent compound: Excited triplet state and singlet oxygen formation exhibit strong molecular oxygen enhancing effect

Zhang, Xianfu; Zhu, Jiale

doi:10.1016/j.jlumin.2019.04.050

Cited by 13 publications

(12 citation statements)

References 34 publications

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“…Therefore, the SR effect on Φ f and τ f is most likely due to the increase of k isc ; e.g., more T 1 is formed. The TAS of S 0C is the same as that reported previously, 32 and it is known that the positive band that peaked at 410 nm is due to triplet−triplet (T 1 −T n ) transient absorption and the negative band is due to the bleaching of the ground state S 0 . For both S 1C and S 3C , the shapes of TAS are very similar to that of S 0C , except for the slight red shift in peak positions.…”

Section: Resultssupporting

confidence: 80%

Thioetherification Inducing Efficient Excited Triplet State and Singlet Oxygen Generation: Heavy Atom-Free BODIPY Photosensitizer Based on the S₁(n,π*) State

Zhang

2021

J. Phys. Chem. C

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We have examined the ability of the newly synthesized thioalkyl and thiophenyl (SR) BODIPYs to generate the excited triplet state (T 1 ) using the laser flash photolysis technique. Compared to the unsubstituted BODIPY parent, SR BODIPYs are much more efficient in generating T 1 . We have also determined the capability of the SR BODIPYs to yield singlet oxygen O 2 ( 1 Δ g ) using two methods: (1) measuring the steady state and time-resolved NIR phosphorescence that peaked at 1270 nm; (2) recording DPBF decomposition caused by the reaction with singlet oxygen. The results show that both thioalkyl and thiophenyl very remarkably increase the quantum yield of singlet oxygen formation up to 0.83 from 0.10. To understand the mechanism, we have studied the related photophysics using steady state and time-resolved fluorescence and UV−vis absorption, as well as quantum chemical calculations based on Density Functional Theory. Both the thioalkyl and thiophenyl remarkably decrease the quantum yield of fluorescence and shorten the fluorescence lifetime of BODIPYs, they also cause the occurrence of a new S 1 (n,π*) with a slightly lower energy than S 1 (π,π*). Since intersystem crossing (ISC) from S 1 (n,π*) to T 1 (π,π*) is symmetrically allowed, while ISC from S 1 (π,π*) to T 1 (π,π*) is symmetrically forbidden, this explains why SR presence renders BODIPY efficient photosensitizer for excited triplet state and singlet oxygen generation. SR induced efficient T 1 formation is different from the cases of carbonyl (CO) or thiocarbonyl (CS). This finding provides a new method to get efficient heavy atom free photosensitizers, which is important in developing new generation photosensitizers for photodynamic therapy, photochemical up conversion of near IR sunlight in solar cell, and photoredox catalysis.

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Section: Resultssupporting

confidence: 80%

Thioetherification Inducing Efficient Excited Triplet State and Singlet Oxygen Generation: Heavy Atom-Free BODIPY Photosensitizer Based on the S₁(n,π*) State

Zhang

2021

J. Phys. Chem. C

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“…Boron dipyrromethene (BODIPY) is an excellent example in using CS-CR to generate T 1 and singlet oxygen. The BODIPY parent compound itself (the acceptor in Figure ) shows fairly low quantum yield for T 1 and singlet oxygen formation (Φ T and Φ Δ , respectively) because its radiation decay is much faster than intersystem crossing (ISC) so that its fluorescence quantum yield is near unity (Φ f ≈ 1.0) . By attaching an anthracene (or another BODIPY) as the electron donor, Φ T and Φ Δ of the modified BODIPY can be increased to be over 0.90. ,, It has been shown that attaching pyrene, 2-methoxy naphthalene, or 4-amino benzene can also very effectively promote the formation of T 1 and singlet oxygen via CS-CR process.…”

Section: Introductionmentioning

confidence: 99%

Minimizing the Electron Donor Size of Donor–Acceptor-Type Photosensitizer: Twisted Intramolecular Charge-Transfer-Induced Triplet State and Singlet Oxygen Formation

Zhang³

et al. 2020

J. Phys. Chem. C

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Efficient and selective heavy atom-free singlet oxygen photosensitizers (HAFPS) are highly desirable for chemistry, pharmaceutical sciences, phototherapy, and environmental sciences. The donor–acceptor (D–A)-type HAFPS based on charge transfer/charge recombination mechanism usually requires that a photosensitizing chromophore A (such as boron dipyrromethene (BODIPY)) is attached by a large and perpendicular aryl donor D in its ground state. In this report, however, we show that much smaller non-aryl dialkylamino donors also enable BODIPY to generate singlet oxygen and excited triplet state selectively and very efficiently in nonpolar media. The mechanism is that the photoexcitation of NR2-BODIPY leads to the twisting of the NR2 so that a vertical geometry is formed, which best facilitates T1 formation via intramolecular charge transfer/charge recombination processes. This small NR2 group modification does not need any aryl (pyrenyl, anthracyl, BODIPY, naphthyl, and phenyl) to enhance the intersystem crossing; therefore the synthesis is very facile and the material is atom-economic. The synthesis contains neither halogen atoms nor heavy metal ions so that this novel strategy provides more environment- and health-friendly singlet oxygen photosensitizers for use in chemical synthesis, pharmaceutical sciences, phototherapy, environmental sciences, and physiology.

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“…Specifically, the transient fluorescence decay curves of B-Cbl-3 before and after preirradiation of green light yield average excited-state lifetimes of 3.86 and 7.38 ns, respectively, suggesting the green-lighttriggered photocleavage reaction and the consequent generation of BODIPY derivative with excited-state behavior were remarkedly different from that of the B-Cbl-3. 38,39 B-Cbl-3-Mediated Singlet Oxygen Generation upon Green-Light Phototriggering. Figure 2a displayed the electron spin resonance (ESR) characterization results of B-Cbl-3 before and after 550 nm light irradiation using 2, 2, 6, 6tetramethylpiperidine (TEMP) as the 1 O 2 trapping agent.…”

Section: ■ Results and Discussionmentioning

confidence: 65%

“…The picosecond time-resolved fluorescence characterization provided further information regarding the green-light-mediated formation of reaction product from B-Cbl-3 (Figure S3). Specifically, the transient fluorescence decay curves of B-Cbl-3 before and after preirradiation of green light yield average excited-state lifetimes of 3.86 and 7.38 ns, respectively, suggesting the green-light-triggered photocleavage reaction and the consequent generation of BODIPY derivative with excited-state behavior were remarkedly different from that of the B-Cbl-3. , …”

Section: Results and Discussionmentioning

confidence: 89%

Single-Chromophore-Based Therapeutic Agent Enables Green-Light-Triggered Chemotherapy and Simultaneous Photodynamic Therapy to Cancer Cells

Liu

Meng

Bao

et al. 2019

ACS Appl. Bio Mater.

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A new type of single-chromophore-based photoactivatable prodrug (B-Cbl-3) enabling green-light-triggered chemotherapy and simultaneous photodynamic therapy with superb therapeutic efficacy was developed by conjugating a photoactive BODIPY derivative with an antitumor chlorambucil moiety. The optimized BODIPY moiety markedly enabled high efficient photogeneration of 1 O 2 and fluorescence emission with distinct colors before and after photorelease of chlorambucil. The preliminary biological experiment results have verified the efficient photorelease of chlorambucil from B-Cbl-3 and the huge contrast in cytotoxicity between them, superior combined therapeutic performance based on extraordinary low doses of drug and light irradiation, and ratiometric fluorescence imaging for in situ monitoring drug release. The salient superiority of B-Cbl-3 regarding alleviating the attenuation of triggering light caused by optically turbid tissue that short-wavelength lights typically encounters has also been verified.

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BODIPY parent compound: Excited triplet state and singlet oxygen formation exhibit strong molecular oxygen enhancing effect

Cited by 13 publications

References 34 publications

Thioetherification Inducing Efficient Excited Triplet State and Singlet Oxygen Generation: Heavy Atom-Free BODIPY Photosensitizer Based on the S₁(n,π*) State

Thioetherification Inducing Efficient Excited Triplet State and Singlet Oxygen Generation: Heavy Atom-Free BODIPY Photosensitizer Based on the S₁(n,π*) State

Minimizing the Electron Donor Size of Donor–Acceptor-Type Photosensitizer: Twisted Intramolecular Charge-Transfer-Induced Triplet State and Singlet Oxygen Formation

Single-Chromophore-Based Therapeutic Agent Enables Green-Light-Triggered Chemotherapy and Simultaneous Photodynamic Therapy to Cancer Cells

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BODIPY parent compound: Excited triplet state and singlet oxygen formation exhibit strong molecular oxygen enhancing effect

Cited by 13 publications

References 34 publications

Thioetherification Inducing Efficient Excited Triplet State and Singlet Oxygen Generation: Heavy Atom-Free BODIPY Photosensitizer Based on the S1(n,π*) State

Thioetherification Inducing Efficient Excited Triplet State and Singlet Oxygen Generation: Heavy Atom-Free BODIPY Photosensitizer Based on the S1(n,π*) State

Minimizing the Electron Donor Size of Donor–Acceptor-Type Photosensitizer: Twisted Intramolecular Charge-Transfer-Induced Triplet State and Singlet Oxygen Formation

Single-Chromophore-Based Therapeutic Agent Enables Green-Light-Triggered Chemotherapy and Simultaneous Photodynamic Therapy to Cancer Cells

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Thioetherification Inducing Efficient Excited Triplet State and Singlet Oxygen Generation: Heavy Atom-Free BODIPY Photosensitizer Based on the S₁(n,π*) State

Thioetherification Inducing Efficient Excited Triplet State and Singlet Oxygen Generation: Heavy Atom-Free BODIPY Photosensitizer Based on the S₁(n,π*) State