Emim-R离子液体气相结构与光谱的密度泛函理论研究

应用B3LYP/6-31G(d)方法研究了气相状态下一系列复杂阴离子BF_4~-、AlCl_4~-、PF_6~-、NO_3~-、CF_3COO~-、CF_3SO_3~-、HSO_4~-及其与阳离子[Emim~ ]形成的离子液体[Emim]BF_4、[Emim]AlCl_4、[Emim]PF_6、[Emim]CF_3COO、[Emim]CF_3SO_3、[Emim] HSO_4、[Emim]NO_3的结构和红外光谱,分析了阴阳离子的结合方式及其相互作用。[Emim]BF_4和[Emim]PF_6的计算结果与前人的计算结果及实验观测值符合得较好。研究发现含有O原子的阴离子与阳离子的相互作用比其它的阴离子都强,其中NO_3最强。

DFT study on the structure and spectrum of Emim-R ionic liquids

Ionic liquids which are liquids composed completely of anions and cations at ambient temperature.They have many attractive properties,and have been widely and successfully applied many fields.Science the structural properties are the key points to under- standing the thermodynamic,dynamic,and other properties of ionic liquids,it is very important to understand the structural properties of ionic liquids.In the paper,a series of complex anions such as BF_4~-,AlCl_4~-,PF_6~-,NO_3~-,CF_3COO~-,CF_3SO_3~- and HSO_4~- and the ionic liquids formed by these anions and 1-ethyl-3-methylimidazolium are studied by the density functional theory at B3LYP/6-31G(d) level.The geometry structure,IR spectra of anions and ionic liquids as well as the interactions between cation and anions of ionic liq- uids are obtained and analyzed.The calculated results for Emim BF_4 and Emim PF_6 agree well with the experimental results.It is found that the interactions between cation and anions are stronger for the anions with oxygen atoms than others,the strongest one is NO_3~-.