Zhao Xin, Yin Hang, Zhang Wentian, Guo Jie, Shi Ying
Institute of Atomic and Molecular Physics, Jilin University, Changchun, 130012, China.
Phys Chem Chem Phys. 2023 Aug 16;25(32):21604-21611. doi: 10.1039/d3cp02237d.
We present novel insights into the interplay between excited state intramolecular proton transfer (ESIPT) and spin-orbit coupling (SOC) in the 10-hydroxy-11-benzo[]fluoren-11-one (10-HHBF) molecule, utilizing the time-dependent density functional theory approach and femtosecond transient absorption spectroscopy. Our discoveries entail a reassessment of the luminescence mechanism for 10-HHBF, characterizing it as an ESIPT fluorophore. Additionally, we demonstrate that the molecule undergoes intersystem crossing (ISC) following proton transfer, which quenches the fluorescence of the proton-transferred state, thus resulting in the absence of dual emission and a limited spectral range of fluorescence. Furthermore, our investigation reveals that 10-HHBF displays an SOC enhancement feature induced by ESIPT, which facilitates the ISC process. This trait serves as a barrier to the application of 10-HHBF in single-molecule white light emitters (SMWLEs). Our findings underscore the notable influence of the ESIPT-induced spin-orbit interaction enhancement on luminescent properties, which necessitates consideration in the design of SMWLEs.
我们利用含时密度泛函理论方法和飞秒瞬态吸收光谱，对10-羟基-11-苯并[]芴-11-酮（10-HHBF）分子中激发态分子内质子转移（ESIPT）与自旋-轨道耦合（SOC）之间的相互作用提出了新的见解。我们的发现需要对10-HHBF的发光机制进行重新评估，将其表征为一种ESIPT荧光团。此外，我们证明该分子在质子转移后会发生系间窜越（ISC），这会淬灭质子转移态的荧光，从而导致不存在双发射且荧光光谱范围有限。此外，我们的研究表明，10-HHBF表现出由ESIPT诱导的SOC增强特征，这促进了ISC过程。这一特性成为10-HHBF在单分子白光发射体（SMWLEs）中应用的障碍。我们的研究结果强调了ESIPT诱导的自旋-轨道相互作用增强对发光性质的显著影响，这在SMWLEs的设计中需要加以考虑。
