基于咔唑的双光子荧光次氯酸根探针光学性质及响应机理

采用含时密度泛函理论与响应函数理论相结合的方法，研究了两种实验室新合成的水溶性双光子荧光次氯酸根（ClO^-）探针分子HCH和HCM的单光子吸收、双光子吸收和荧光发射性质。计算结果表明，HCH和HCM分子与ClO^-反应后，生成物的光吸收和光发射性质均发生明显变化，相应的吸收和发射峰位都发生了明显蓝移，荧光强度展现出明显的增强。另外，两探针分子都具有较大的双光子吸收截面，且与ClO^-反应后，生成物的双光子吸收截面值显著增加，因此两分子均可作为性能优良的双光子荧光探针分子。此外，通过分析HCH和HCM分子与ClO^-反应前后的Mulliken电荷布居情况，从理论上证实了该系列荧光探针分子的识别机理是C＝N异构化。

Optical Properties and Responsive Mechanism of Carbazole-Based Two-Photon Fluorescent Probes for the Detection of Hypochlorite

The one- and two-photon absorption and emission properties of the two newly synthesized watersoluble two-photon fluorescent probes (HCH and HCM) for the detection of ClO^- were investigated using timedependent density functional theory in combination with response theory. Dramatic changes in the photophysical properties of the molecules following reaction with ClO^- were predicted. The photoabsorption and photoemission peaks for both compounds were clearly blue shifted, while the emission intensities were enhanced. Both probes were also found to have large two-photon cross sections. Importantly, in the presence of ClO^- the two-photon cross section of the molecules increased significantly, which indicated that both HCH and HCM should be good two-photon fluorescent probes for sensing ClO^-. The responsive mechanism of the probes was explored by analyzing the molecular Mulliken charge population, which was attributed to C=N isomerization.