Excited-state intramolecular proton transfer (ESIPT) process based on ‘naked’ diazaborepins (NDABs) by modification on the parent structure (NDAB-H) is confirmed by experiment and theory calculation. An emission peak is detected at longer wavelength with large Stokes shift in toluene, and a new emission shoulder gradually appeared at short wavelength as the increase of solvent polarity, indicating the ESIPT process is tuned by solvent. Herein, the solvent effect and the mechanism of the ESIPT reaction are further investigated by DFT calculation. Without considering the effect of proton in solvent, seven aprotic solvents with different dielectric constant from DMSO (46.8) to cyclohexane (1.18) are chosen. Typical bond lengths, angles, electron distribution and transfer on frontier molecular orbital and thermodynamics analysis are discussed in different solvents for comparison. This work proved that the ESIPT process is inhibited as the increase of the solvent polarity that is in good agreement with the experimental date.

通过修饰母体结构（NDAB-H），基于“裸”重氮杂配蛋白（NDAB）的激发态分子内质子转移（ESIPT）过程）通过实验和理论计算得到证实。在较长的波长处检测到一个发射峰，甲苯中的斯托克斯位移较大，并且随着溶剂极性的增加，在短波长处逐渐出现了一个新的发射峰，这表明ESIPT过程受溶剂的影响。在此，通过DFT计算进一步研究了溶剂效应和ESIPT反应的机理。在不考虑质子在溶剂中的影响的情况下，选择了介电常数从DMSO（46.8）到环己烷（1.18）不同的七种非质子溶剂。在不同溶剂中讨论了前沿分子轨道和热力学分析中的典型键长，键角，电子分布和转移，以进行比较。