Ito Naoki, Huang Wei, Richert Ranko
Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona 85287-1604, USA.
J Phys Chem B. 2006 Mar 9;110(9):4371-7. doi: 10.1021/jp056960v.
We have measured the dynamics of solvation of a triplet state probe, quinoxaline, in the glass-forming ionic liquid dibutylammonium formate near its glass transition temperature Tg=153 K. The Stokes-shift correlation function displays a relaxation time dispersion of considerable magnitude and the optical line width changes systematically along the solvation coordinate. The solvent dynamics in the viscous regime is compared with the rotational behavior of the solute and with the dielectric relaxation of the ionic liquid. Among the different quantities derived from the dielectric experiments, the relaxation of the macroscopic electric field, i.e., the modulus Mt, matches best the solvent response Ct regarding time scale and stretching exponent. Many other properties are reminiscent of the behavior of polar molecular liquids which lack the ionic character.
我们测量了三重态探针喹喔啉在玻璃态离子液体甲酸二丁铵中接近其玻璃化转变温度Tg = 153 K时的溶剂化动力学。斯托克斯位移相关函数显示出相当大的弛豫时间色散，并且光学线宽沿溶剂化坐标系统地变化。将粘性区域中的溶剂动力学与溶质的旋转行为以及离子液体的介电弛豫进行了比较。在介电实验得出的不同量中，宏观电场的弛豫，即模量Mt，在时间尺度和拉伸指数方面与溶剂响应Ct最匹配。许多其他性质让人联想到缺乏离子特性的极性分子液体的行为。
