基于超额光谱和氰基探针的离子液体溶液结构研究

Solution structure is an important part of solution chemistry. To investigate solution structure is also one of the most challenging tasks in physical chemistry. Ionic liquids have become one of the hotspot research fields due to its potential applications in various fields such as electrochemistry, catalysts. Currently, the study of ionic liquids mainly focuses on design, development and application of task-specific ionic liquids, while the study on solution structure and the effect of incorporating additional functional groups is rare. In this work, we will take advantage of the high resolution of excess spectra and the high sensitivity of infrared probe molecules to study the solution structure in ether-based functional/non-functional ionic liquids and acetonitrile binary systems. Imidazolium- and pyrrolidinium-based ionic liquids are selected as ionic liquids and acetonitrile is used as co-solvent and infrared probe molecule. Clusters and solution structure in the whole concentration can be revealed by employed both experimental and theoretical methods, especially the combination of excess spectra and infrared probe molecules. Comparative study of ether-based functional and non-functional ionic liquids will also be performed to essentially elucidate the effect of incorporating ether-based functional groups on solution structure and physicochemical properties. This study will provide theoretical insight and vital instruction on designing ionic liquids and exploring their applications.

溶液结构是溶液化学的重要组成部分，研究溶液结构也是物理化学最具挑战的任务之一。离子液体因在电化学、催化等多个方面表现出优异性能，成为当前化学领域研究的热点之一。目前的研究主要集中在新型功能化离子液体的制备和应用，而对其溶液结构、以及功能化基团引入的影响的研究很少。本项目拟通过将可以提高光谱表观分辨率的超额光谱和高灵敏度的红外探针相结合，研究醚基功能化/未功能化离子液体与乙腈体系的溶液结构。拟选取咪唑、吡咯两类离子液体，以乙腈作为红外探针和共溶剂，综合利用多种实验手段和量子化学计算的方法，特别是将超额光谱和红外探针相结合的方法，对溶液中可能存在的作用体进行指认，进而得到全浓度范围的溶液结构变化。比较醚基功能化和未功能化离子液体的溶液结构差别，从本质上揭示醚基的引入对离子液体溶液结构和物理化学性质的影响，为功能化离子液体的设计、开发以及应用提供理论上的指导。

溶液结构是溶液化学的重要组成部分，研究溶液结构也是物理化学最具挑战的任务之一。醚基功能化离子液体在电化学和能源等领域受到了越来越多的关注，但是关于醚基功能化离子液体微观结构的基础研究却鲜有报道。本项目综合利用红外光谱、超额光谱和量子化学计算的方法，对醚基功能化/非功能化离子液体进行了研究。本项目研究的主要内容为：对离子液体与共溶剂体系中可能存在的作用体进行了指认，比较醚基的引入对于离子液体体系的氢键相互作用的影响，比较了阴离子为[TFSI]−和[FSI]−的醚基功能化离子液体的氢键和微观结构的不同等。其主要的结论有：1）[EOMIM]+可以与C2−H和C5−H形成分子内氢键，且与C2−H形成的氢键比较稳定；2）在离子液体中引入醚基，会使阴阳离子间以及阳离子与溶剂间的氢键作用减弱；3）对多个体系中溶液中存在的可能的作用体进行了指认；4）醚基功能化离子液体与不同的共溶剂作用，其主要的作用位点可能发生变化等。该课题揭示醚基的引入对离子液体溶液结构和氢键相互作用的影响，为功能化离子液体的设计、开发以及应用提供理论上的指导。