School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou, 510006, P. R. China.
Department of Chemistry and Key Laboratory for Preparation and Application of Ordered Structural Materials of Guangdong Province, Shantou University, Shantou, 515063, P. R. China.
Phys Chem Chem Phys. 2022 Sep 14;24(35):20901-20912. doi: 10.1039/d2cp02897b.
Herein, a series of compact anthracene carboxyimide (ACI) based donor-acceptor dyads were prepared by substituting bulky aryl moieties with various electron-donating ability to study the triplet-excited state properties. The ISC mechanism and triplet yield of the dyads were successfully tuned structural manipulation. Efficient ISC ( ≈ 99%) and long-lived triplet state ( ≈ 122 μs) was observed for the orthogonal anthracene-labeled ACI derivative compared to the Ph-ACI and NP-ACI dyads, which showed fast triplet state decay ( ≈ 7.7 μs). Femtosecond transient absorption study demonstrated the ultrafast charge separation (CS) and efficient charge recombination (CR) in the orthogonal dyads and ISC occurring spin-orbit charge transfer (SOCT) mechanism (AN-ACI: = 355 fs, = 2.41 ns; PY-ACI: = 321 fs, = 1.61 ns), while in Ph-ACI and NP-ACI dyads triplet populate following the normal ISC channel (nπ* → ππ* transition), no CS was observed. We found that the attachment of suitable aryl donor moiety (AN- or PY-) to the ACI core can ensure the insertion of the intermediate triplet state, resulting in a small energy gap among charge separated state (CSS) and triplet state, which leads to efficient ISC in these derivatives. The SOCT-ISC-based AN-ACI dyad was confirmed to be a potent photodynamic therapeutic reagent; an ultra-low IC value (0.27 nM) that was nearly 214 times lower than that of the commercial Rose Bengal photosensitizer (57.8 nM) was observed.
本文通过用各种供电子能力的大体积芳基取代基取代蒽基羧基酰亚胺（ACI）的给体-受体二聚体，来制备一系列紧凑型蒽基 ACI 基给体-受体二聚体，以研究三重激发态性质。通过结构操纵，成功地调节了ISC 机制和三重态产率。与 Ph-ACI 和 NP-ACI 二聚体相比，正交蒽基标记的 ACI 衍生物具有高效的 ISC（ ≈ 99%）和长寿命的三重态（ ≈ 122 μs），而 Ph-ACI 和 NP-ACI 二聚体表现出快速的三重态衰减（ ≈ 7.7 μs）。飞秒瞬态吸收研究表明，正交二聚体中发生超快电荷分离（CS）和有效的电荷复合（CR），ISC 通过自旋轨道电荷转移（SOCT）机制发生（AN-ACI： = 355 fs， = 2.41 ns；PY-ACI： = 321 fs， = 1.61 ns），而在 Ph-ACI 和 NP-ACI 二聚体中，三重态的产生遵循正常的 ISC 通道（nπ*→ππ*跃迁），没有观察到 CS。我们发现，合适的芳基供体（AN-或 PY-）部分与 ACI 核心的连接可以确保插入中间三重态，从而导致电荷分离态（CSS）和三重态之间的能隙较小，这导致这些衍生物中发生有效的 ISC。基于 SOCT-ISC 的 AN-ACI 二聚体被证实是一种有效的光动力治疗试剂；观察到超低的 IC 值（0.27 nM），比商业 Rose Bengal 光敏剂（57.8 nM）低 214 倍。
