高浓度NaBF_4/DMF溶液中的离子溶剂化和离子缔合  

Ion Solvation and Ion Association in High-Concentration of NaBF_4 /DMF Solutions

作　　者：轩小朋[1] 汤俊明[1] 王键吉[1] 汪汉卿[2] 

机构地区：[1]河南师范大学化学与环境科学学院,河南新乡453007 [2]中国科学院兰州化学物理研究所,甘肃兰州730000

出　　处：《光谱学与光谱分析》2005年第4期548-552,共5页Spectroscopy and Spectral Analysis

基　　金：国家自然科学基金 (2 99730 0 9);河南师范大学青年科学基金 (2 0 0 4 0 0 7)资助项目

摘　　要：利用振动光谱技术和量子化学方法研究了NaBF4/DMF溶液中的离子缔合和离子溶剂化现象。DMF分子的谱带变化表明,Na+ 与DMF分子的相互作用是通过DMF分子羰基上的氧原子进行的。Na+ 的溶剂化层内含有4个DMF分子,呈近似的四面体结构。而BF-4谱带的变化表明,溶液中存在着离子缔合,有直接接触离子对生成。直接接触离子对的含量随溶液浓度增加而增大。Ion solvation and ion association in solutions of NaBF4/DW were studied by infrared and Raman spectroscopy and ab initio quantum chemistry. It was found that the sodium cation interacts on oxygen atom of C=O group in DNIF molecules. The solvation number of Na+, four, was obtained according to the change analysis of CH3 rocking band. The splitting of the v, mode of BF4- anion indicates the presence of contact ion pairs. Ionic association degree increases with increasing molality of the salt. The solvated structure of Na+ and the geometry of Li+ BF4- ion pair were also suggested based on the ab initio calculations.

关 键 词：离子溶剂化 离子缔合 DMF 溶液 接触离子对 量子化学方法 NA^+ 四面体结构 光谱技术 相互作用 浓度增加 分子 氧原子 谱带 羰基 近似 

分 类 号：O645.13[理学—物理化学] O646.1[理学—化学]