Wang Yaping, Zhao Zhengyan, Li Guanglan, Yan Yang, Hao Ce
State Key Laboratory of Fine Chemicals, Dalian University of Technology, Panjin, 124221, China.
State Key Laboratory of Fine Chemicals, Dalian University of Technology, Dalian, 116024, China.
J Mol Model. 2018 Jun 7;24(7):153. doi: 10.1007/s00894-018-3676-x.
Formaldehyde is the main cause of indoor pollution. In this research, we investigated the mechanism that the covalent organic framework (COF) identifies formaldehyde applying density functional theory (DFT) and time-dependent (TD) DFT approaches. On one hand, the calculation results of the geometric parameters, IR spectra, as well as H-NMR chemical shifts for protons that associated with the hydrogen bonding formation together with the electronic transition energies verified that the furcate hydrogen bonding formed between the COF and formaldehyde is enhanced in the excited S state and it is not beneficial to luminescence of the COF. On the other hand, excitingly, our further calculation results of the fluorescence rate coefficients also revealed that the strengthened hydrogen bonding behavior in S state caused an efficiently weakened luminescent phenomenon compared with that of the COF. Therefore, this analysis method, which qualitative collaborates with quantitative theoretically, demonstrates the possibility that the COF could be served as a sensor to detect formaldehyde. Graphical Abstract The luminescence of the Covalent Organic Framework can be greatly weakened after the addition of formaldehyde.
甲醛是室内污染的主要原因。在本研究中，我们运用密度泛函理论（DFT）和含时密度泛函理论（TD-DFT）方法，研究了共价有机框架（COF）识别甲醛的机制。一方面，与氢键形成相关的质子的几何参数、红外光谱以及氢核磁共振化学位移的计算结果，连同电子跃迁能量，证实了COF与甲醛之间形成的分叉氢键在激发单重态（S态）中增强，且这对COF的发光不利。另一方面，令人兴奋的是，我们对荧光速率系数的进一步计算结果还表明，与COF相比，S态中增强的氢键行为导致了发光现象的有效减弱。因此，这种定性与定量理论相结合的分析方法，证明了COF用作检测甲醛传感器的可能性。图形摘要 加入甲醛后，共价有机框架的发光会大大减弱。
