Outsourcing Intersystem Crossing without Heavy Atoms: Energy Transfer Dynamics in PyridoneBODIPY–C 60 Complexes
Outsourcing Intersystem Crossing without Heavy Atoms: Energy Transfer Dynamics in PyridoneBODIPY–C 60 Complexes
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外包无重原子的系间穿越：吡啶酮BODIPY™C 60 配合物中的能量转移动力学
DOI：
10.1021/acs.jpclett.2c02388
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发表时间：
2022
期刊：
影响因子：
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通讯作者：
Blank, David A.
中科院分区：
文献类型：
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作者：
Swedin, Rachel K.;Healy, Andrew T.;Schaffner, Jacob W.;Kuzmin, Ilya A.;Zatsikha, Yuriy V.;Nemykin, Victor N.;Blank, David A.
利用时间分辨光谱研究了两种完全表征的吡啶酮BODIPY-富勒烯复合物的激发态动力学。光激发最初定位在吡啶酮BODIPY发色团上。能量迅速转移到富勒烯，随后经历ISC以形成三重态，并通过三重态-三重态能量转移将能量返回到吡啶酮BODIPY。这种乒乓能量转移机制导致激发态吡啶酮BODIPY组分的有效（>85%）总体转化，尽管在不存在富勒烯配偶体的情况下吡啶酮BODIPY中完全缺乏ISC。富勒烯附着化学的微小差异并不影响初始的单重态能量转移。然而，与异恶唑基桥相比，N-甲基吡咯烷桥确实减慢了三重态-三重态能量转移和最终三重态的最终弛豫速率。每个步骤的速率被量化，并使用计算预测来补充所提出的机制和能量学。结果证明了缺乏显著自旋-轨道耦合的强发色团的有效三重态敏化。
The excited state dynamics in two fully characterized pyridoneBODIPY–fullerene complexes were investigated using time-resolved spectroscopy. Photoexcitation was initially localized on the pyridoneBODIPY chromophore. The energy was rapidly transferred to the fullerene, which subsequently underwent ISC to form a triplet state and returned the energy to the pyridoneBODIPY via triplet–triplet energy transfer. This ping-pong energy transfer mechanism resulted in efficient (>85%) overall conversion of the excited state pyridoneBODIPY constituent despite a complete lack of ISC in the pyridoneBODIPY in the absence of the fullerene partner. The small difference in attachment chemistry for the fullerene did not impact the initial singlet energy transfer. However, theN-methylpyrrolidine bridge did slow both the triplet–triplet energy transfer and the ultimate relaxation rate of the final triplet state when compared to an isoxazole-based bridge. The rates of each step were quantified, and computational predictions were used to complement the proposed mechanism and energetics. The result demonstrated efficient triplet sensitization of a strong chromophore that lacks significant spin–orbit coupling.