Xia Zhicheng, Xu Honghong, Huang Anran, Hao Wenxuan, Wu Dongxia, Yin Shibin, He Haixiang
College of Chemistry and Chemical Engineering, Guangxi University, Nanning, 530004, China.
Guangxi Colleges and Universities Key Laboratory of Applied Chemistry Technology and Resource Development, Guangxi University, Nanning, 530004, China.
J Fluoresc. 2024 Sep 19. doi: 10.1007/s10895-024-03911-6.
As one of the biomolecules, hydrogen sulfide (HS) has received a lot of attention. Recent studies have shown that endogenous hydrogen sulfide plays different roles in different organs in biological systems. Fluorescent probe technology has been widely adopted due to its many advantages such as low cost, simple operation, and high sensitivity. Among many probes, dicyanoisophorone fluorophore is often used in probe design for real-time detection of endogenous HS due to the large Stokes shift and long fluorescence emission wavelength. In this paper, the fluorescence sensing mechanism of dicyanoisophorone-like probe L and its product 3 with near-infrared fluorescence emission has been theoretically investigated by using theory methods. The analysis of infrared (IR) vibration spectra and reduced density gradient (RDG) showed that the hydrogen bond of the enolic structure of product 3 was significantly enhanced in the S state. The spectroscopic information revealed that the emission of NIR fluorescence originated from the keto structure of the product. Finally, potential energy curves and frontier molecular orbitals diagrams showed that the fluorescence quenching phenomenon of the probe L was attributed to the photoinduced electron transfer (PET) process, whereas the product 3 generated after the detection of HS undergoes the excited state intramolecular proton transfer (ESIPT) process.
作为生物分子之一，硫化氢（HS）受到了广泛关注。最近的研究表明，内源性硫化氢在生物系统的不同器官中发挥着不同作用。荧光探针技术因其成本低、操作简单、灵敏度高等诸多优点而被广泛采用。在众多探针中，二氰基异佛尔酮荧光团由于斯托克斯位移大、荧光发射波长长，常被用于内源性HS实时检测的探针设计中。本文采用理论方法对具有近红外荧光发射的二氰基异佛尔酮类探针L及其产物3的荧光传感机制进行了理论研究。红外（IR）振动光谱和密度降低梯度（RDG）分析表明，产物3烯醇结构的氢键在S态中显著增强。光谱信息表明，近红外荧光发射源于产物的酮结构。最后，势能曲线和前线分子轨道图表明，探针L的荧光猝灭现象归因于光诱导电子转移（PET）过程，而检测HS后生成的产物3经历激发态分子内质子转移（ESIPT）过程。
