Ding Sha, Xu Aixiang, Sun Aokui, Xia Yong, Liu Yuejun
School of Packaging and Materials Engineering, Hunan University of Technology, Zhuzhou 412007, PR China.
Hunan Key Laboratory of Biomass Fiber Functional Materials, Hunan University of Technology, Zhuzhou 412007, PR China.
ACS Omega. 2020 Jul 31;5(31):19695-19701. doi: 10.1021/acsomega.0c02393. eCollection 2020 Aug 11.
DFT and TDDFT calculations are adopted to study the sensing mechanism of a turn-on-type cysteine fluorescent probe (2-(1-phenyl-imidazo[1,5-α]pyridine-3-yl)phenyl acrylate, denoted as MZC-AC). The photoinduced electron transfer (PET) process of MZC-AC and the excited state intramolecular proton transfer (ESIPT) process of MZC have been investigated in detail. We demonstrate that the fluorescence quenching of MZC-AC is ascribed to the PET mechanism and the large Stokes shift fluorescence emission of MZC is the result of the ESIPT mechanism. The results have been cross-validated by geometries, frontier molecular orbital analysis, and potential energy curve scanning. As a result, our calculations completely reproduce the experimental results and give powerful evidence for the sensing mechanism of MZC-AC for cysteine.
采用密度泛函理论（DFT）和含时密度泛函理论（TDDFT）计算来研究一种开启型半胱氨酸荧光探针（2-(1-苯基-咪唑并[1,5-α]吡啶-3-基)苯基丙烯酸酯，记为MZC-AC）的传感机制。详细研究了MZC-AC的光致电子转移（PET）过程以及MZC的激发态分子内质子转移（ESIPT）过程。我们证明，MZC-AC的荧光猝灭归因于PET机制，而MZC的大斯托克斯位移荧光发射是ESIPT机制的结果。通过几何结构、前线分子轨道分析和势能曲线扫描对结果进行了交叉验证。结果表明，我们的计算完全重现了实验结果，并为MZC-AC对半胱氨酸的传感机制提供了有力证据。
