Department of Chemistry, Indian Institute of Technology, Kharagpur 721 302, West Bengal, India.
J Phys Chem B. 2010 Mar 4;114(8):2779-89. doi: 10.1021/jp907936s.
The effect of the addition of cosolvents in the room temperature ionic liquid (RTIL) 1-ethyl-3-methylimidazolium ethyl sulfate ([Emim][EtSO(4)]) was probed by the solvent and rotational relaxation studies of coumarin 153 in neat ionic liquid [Emim][EtSO(4)] and [Emim][EtSO(4)]-cosolvent mixtures by using steady-state and time-resolved fluorescence spectroscopy. With gradual addition of cosolvents in the RTIL, both the average solvation time and rotational relaxation times gradually decrease. Addition of cosolvents in the IL decreases the viscosity of the medium. We have optimized the geometry of [Emim][EtSO(4)] and [Emim][EtSO(4)]-cosolvent mixtures by using quantum chemical calculations using density functional theory methods, which show the formation of hydrogen bond between cosolvents with [Emim][EtSO(4)]. With addition of the same amount of alcohols in neat [Emim][EtSO(4)], the rotational relaxation time decreases more compared to the addition of the same amount of water.
通过稳态和时间分辨荧光光谱法研究了溶剂和香豆素 153 在纯室温离子液体 1-乙基-3-甲基咪唑硫酸乙酯([Emim][EtSO(4)])和[Emim][EtSO(4)]-共溶剂混合物中的旋转弛豫，考察了共溶剂在室温离子液体([Emim][EtSO(4)])中的添加效果。随着共溶剂在 RTIL 中的逐渐添加，平均溶剂化时间和旋转弛豫时间逐渐减小。离子液体中添加共溶剂会降低介质的粘度。我们使用密度泛函理论方法对[Emim][EtSO(4)]和[Emim][EtSO(4)]-共溶剂混合物的几何形状进行了优化计算，结果表明共溶剂与[Emim][EtSO(4)]之间形成了氢键。在纯[Emim][EtSO(4)]中加入等量的醇，与加入等量的水相比，旋转弛豫时间下降更多。
