发光MOFs检测甲醛过程中的激发态氢键作用及其动力学机理研究

项目名称： 发光MOFs检测甲醛过程中的激发态氢键作用及其动力学机理研究

项目编号： No.21503030

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 数理科学和化学

项目作者： 魏宁宁

作者单位： 大连理工大学

项目金额： 21万元

中文摘要： 发光MOFs是一类具有较大比表面积的周期性多孔材料，能够与甲醛通过氢键作用形成复合物，进而改变其发光性质，在甲醛检测方面有很大的应用前景。研究激发态下氢键的动力学行为是理解发光MOFs对甲醛分子的识别和化学传感机制的关键。本项目根据已有的单晶结构，截取代表性结构基元，构建发光MOFs-甲醛氢键复合物，采用含时密度泛函理论研究激发态下氢键行为对MOFs发光性能的影响。考察MOFs-甲醛复合物中各种常规和非常规氢键在激发态下的行为，研究不同电子态下氢键行为的异同和内在联系，揭示激发态下氢键的本质；探索激发态的能量转移、电荷转移、质子转移以及辐射跃迁与非辐射跃迁竞争，阐述氢键作用与MOFs发光性能的关系；深入理解发光MOFs的分子识别和化学传感机制，掌握通过氢键作用来调整和控制MOFs体系光物理和光化学行为的方法，设计开发可用于甲醛检测的新型发光MOFs材料。

中文关键词： 氢键动力学；电子激发态；电荷转移；质子转移；发光量子产率

英文摘要： Porous metal-organic frameworks (MOFs) can be a highly sensitive colorimetric sensor to successively detect formaldehyde in a single-crystal-to-single-crystal fashion because of the hydrogen bonding between MOFs and formaldehyde. Hydrogen bonding in the electronically excited state is very important to understand the switchable properties of luminescent MOFs which can be used as chemical sensors. In this project, the hydrogen-bonded MOFs-formaldehyde complex is constructed based on the representative cluster clipped from the crystal structure. Time-dependent functional theory (TDDFT) is used to investigate the behavior of hydrogen bonding in the excited state as well as the relationship between hydrogen bonding and luminescent properties of MOFs. Upon electronically excitation, the dynamics of various normal and abnormal hydrogen bonds of MOFs-formaldehyde complex are explored by both computational and experimental methods. To understand the nature of excited-state hydrogen bonding, the similarity and difference of hydrogen bonding between ground state and excited state are investigated in detail. In the electronically excited state, the effects of hydrogen bonding on the electronic transition energy, charge transfer, proton transfer, energy transfer, and the competition between radiative and non-radiative transition are explored to obtain the relationship between hydrogen bonding and the luminescent properties of MOFs. The photo-physical and photo-chemical behavior of MOFs can be adjusted and controlled by understanding the sensing mechanism of MOFs. The final goal of this project is to provide theoretical insights and directions to design and develop luminescent functional MOFs which are more effective and sensitive to detect formaldehyde.

英文关键词： Hydrogen Bond Dynamics;Electronically Excited State;Charge Transfer;Proton Transfer;Luminescence Quantum Yield