重新探讨蒽醌类化合物中三重态形成的动力学。

Revisiting the Dynamics of Triplet Formation in Anthraquinones.

机构信息

School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram, Maruthamala PO, Vithuran, Thiruvananthapuram, Kerala 695551, India.

出版信息

J Phys Chem A. 2022 Jun 16;126(23):3680-3687. doi: 10.1021/acs.jpca.2c01980. Epub 2022 Jun 2.

DOI:10.1021/acs.jpca.2c01980

PMID:35655394

Abstract

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 to S followed by efficient ISC via S-T and S-T pathways fosters a high triplet quantum yield (Φ = 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 upon photoexcitation to the "bright" S. Extremely fast ESIPT on S reduces the efficiency of triplet formation via possible ISC pathways involving S and S, resulting in a low Φ (=0.17).

摘要

蒽醌（AQ）及其羟基衍生物 1-羟基蒽醌（HAQ）的三重态形成途径在理论上进行了研究。在线性振子耦合框架内对模型单重态-三重态势能表面上的动力学模拟，阐明了这些分子中可能的内转换（IC）和系间窜越（ISC）途径。从“亮”S 到 S 的超快 IC 衰减，随后通过 S-T 和 S-T 途径有效地进行 ISC，促进 AQ 中高三重态量子产率（Φ=0.90）。在 HAQ 中，在光激发到“亮”S 时，“无势垒”激发态分子内质子转移（ESIPT）的新非辐射通道打开，并与 S 上的 IC 衰减竞争。在 S 上的超快 ESIPT 通过可能涉及 S 和 S 的 ISC 途径降低了三重态形成的效率，导致低 Φ（=0.17）。