Li Guang-Yue, Liu Dong, Zhang Hang, Li Wei-Wei, Wang Feng, Liang Ying-Hua
College of Chemical Engineering, Hebei United University, Tangshan 063009, PR China.
Modern Technology and Education Centre, Hebei United University, Tangshan 063009, PR China.
Spectrochim Acta A Mol Biomol Spectrosc. 2015;149:17-22. doi: 10.1016/j.saa.2015.04.036. Epub 2015 Apr 23.
The fluoride-sensing mechanism of a reported salicylaldehyde-based sensor (J. Photochem. Photobiol. B 2014, 138, 75) has been investigated by the TDDFT method. The present theoretical study indicates that there is an excited-state proton transfer (ESPT) process from the phenolic O-H moiety to the neighbor N atom in the sensor. The added fluoride anion could capture the proton in the O-H moiety and the corresponding phenolic anion is formed, which could inhibit the ESPT process. The experimental UV/Vis and fluorescence spectra are well reproduced by the calculated vertical excitation energies. Frontier molecular orbital analysis indicates that the local excited state of phenolic anion is responsible for its enhanced fluorescence. Due to this reason, the sensor can be used to sense fluoride anion by monitoring the fluorescent change.
已通过TDDFT方法研究了一种报道的基于水杨醛的传感器（《光化学与光生物学杂志B》，2014年，第138卷，第75页）的氟化物传感机制。目前的理论研究表明，传感器中存在从酚羟基部分到相邻氮原子的激发态质子转移（ESPT）过程。添加的氟阴离子可以捕获羟基部分的质子并形成相应的酚阴离子，这可以抑制ESPT过程。计算得到的垂直激发能很好地再现了实验紫外/可见光谱和荧光光谱。前线分子轨道分析表明，酚阴离子的局域激发态是其荧光增强的原因。因此，该传感器可通过监测荧光变化来检测氟阴离子。
