Surface hopping dynamics reveal ultrafast triplet generation promoted by S1–T2–T1 spin-vibronic coupling in 2-mercaptobenzothiazole

Jayakumari, Chithra Mohan; Nag, Probal; Vennapusa, Sivaranjana Reddy

doi:10.1039/d1cp02587b

Cited by 3 publications

(1 citation statement)

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“…Gollnick et al have explained the observed experimental triplet quantum yields based on the S 1 –T 2 /T 1 ISC pathways in these molecules. However, the presence of near-degenerate states in both singlet and triplet domains can open up unexpected IC and ISC pathways, considerably affecting the triplet formation dynamics. − Furthermore, it is essential to understand the mechanism behind the triplet state formation and the precise identification of the long-lived triplet state for tuning a molecule’s photosensitizing ability. With the current developments in computational methods, it is now possible to determine the involved promoter/receiver electronic state of the ISC process.…”

Section: Introductionmentioning

confidence: 99%

Revisiting the Dynamics of Triplet Formation in Anthraquinones

et al. 2022

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Triplet formation pathways in 9,10-anthraquinone (AQ) and its hydroxy derivative, 1-hydroxyanthraquinone (HAQ), are studied theoretically. Dynamics simulations on the model singlet−triplet potential energy surfaces within the linear vibronic coupling framework are performed to elucidate possible internal conversion (IC) and intersystem crossing (ISC) pathways in these molecules. An ultrafast IC decay from the "bright" S 4 to S 1 followed by efficient ISC via S 1 −T 4 and S 1 −T 5 pathways fosters a high triplet quantum yield (Φ T = 0.90) in AQ. In HAQ, a new nonradiative channel of "barrierless" excited-state intramolecular proton transfer (ESIPT) opens up and competes with the IC decay to S 1 upon photoexcitation to the "bright" S 2 . Extremely fast ESIPT on S 2 reduces the efficiency of triplet formation via possible ISC pathways involving S 1 and S 2 , resulting in a low Φ T (=0.17).

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Section: Introductionmentioning

confidence: 99%

Revisiting the Dynamics of Triplet Formation in Anthraquinones

et al. 2022

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Activity-Based Photosensitizers with Optimized Triplet State Characteristics Toward Cancer Cell Selective and Image Guided Photodynamic Therapy

Kilic

Elmazoğlu

Almammadov

et al. 2022

ACS Appl. Bio Mater.

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Activity-based theranostic photosensitizers are highly attractive in photodynamic therapy as they offer enhanced therapeutic outcome on cancer cells with an imaging opportunity at the same time. However, photosensitizers (PS) cores that can be easily converted to activity-based photosensitizers (aPSs) are still quite limited in the literature. In this study, we modified the dicyanomethylene-4 H -chromene (DCM) core with a heavy iodine atom to get two different PSs (DCM O -I, I-DCM O -Cl) that can be further converted to aPS after simple modifications. The effect of iodine positioning on singlet oxygen generation capacity was also evaluated through computational studies. DCM O -I showed better performance in solution experiments and further proved to be a promising phototheranostic scaffold via cell culture studies. Later, a cysteine (Cys) activatable PS based on the DCM O -I core (DCM O -I-Cys) was developed, which induced selective photocytotoxicity along with a fluorescence turn-on response in Cys rich cancer cells.

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Tetraphenyl-1,4-dioxin and Tetraphenyl-pyrane-4-one: Old Molecules, New Insights

Soydan,

Okyar,

Zorlu

et al. 2023

ACS Omega

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Aggregation-induced emission (AIE) is a phenomenon where certain molecules or materials become highly luminescent when they aggregate or come together in a condensed state, such as a solid or a solution. Moreover, new molecules which show AIE properties are designed and synthesized for various applications like imaging, sensing, and optoelectronics. 2,3,5,6-Tetraphenylpyrazine (TPP) is one of the well-established examples of AIE. Herein, 2,3,5,6-tetraphenyl-1,4-dioxin (TPD) and 2,3,4,5-tetraphenyl-4H-pyran-4-one (TPPO), which are old molecules with TPP similarity, were studied, and new insights in terms of structure and aggregation-caused quenching (ACQ)/AIE properties were gained by means of theoretical calculations. Those calculations performed on TPD and TPPO aimed to provide a better understanding of their molecular structures and how they affect their luminescence properties. This information could be used to design new materials with improved AIE properties or to modify existing materials to overcome ACQ.

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Surface hopping dynamics reveal ultrafast triplet generation promoted by S₁–T₂–T₁ spin-vibronic coupling in 2-mercaptobenzothiazole

Abstract: We investigate the T1 formation upon populating the optically “bright” S2 in 2-mercaptobenzothiazole to interpret the underlying relaxation pathways associated with the experimental decay constants reported by D. Koyama and...

Cited by 3 publications

References 43 publications

Revisiting the Dynamics of Triplet Formation in Anthraquinones

Revisiting the Dynamics of Triplet Formation in Anthraquinones

Activity-Based Photosensitizers with Optimized Triplet State Characteristics Toward Cancer Cell Selective and Image Guided Photodynamic Therapy

Tetraphenyl-1,4-dioxin and Tetraphenyl-pyrane-4-one: Old Molecules, New Insights

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