How does water affect the dynamics of the room-temperature ionic liquid 1-hexyl-3-methylimidazolium hexafluorophosphate and the fluorescence spectroscopy of coumarin-153 when dissolved in it?

被引：68

作者：

Annapureddy, Harsha V. R. ^{[1
]}

Hu, Zhonghan ^{[1
]}

Xia, Junchao ^{[1
]}

Margulis, Claudio J. ^{[1
]}

机构：

[1] Univ Iowa, Dept Chem, Iowa City, IA 52242 USA

来源：

JOURNAL OF PHYSICAL CHEMISTRY B | 2008年 / 112卷 / 06期

关键词：

D O I：

10.1021/jp077623k

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

Molecular dynamics simulations of mixtures of 1-hexyl-3-methylimidazolium hexafluorophosphate ([HMIM+][PF6-]) and water have been performed in order to investigate how small amounts of water affect the translational and rotational dynamics of this ionic liquid (IL). We find that water is closely associated with the anions and that its presence enhances both the translational and rotational dynamics of the IL. In agreement with experiments, we find that the fluorescence spectra of Coumarin-153 is red-shifted because of the presence of water. Small amounts of water enhance the speed of relaxation of the solvent surrounding the solute probe after photoexcitation, but only at a "local environment" level. Interconversion between environments still occurs on a long time scale compared with the fluorescence lifetime of the probe. Excitation wavelength-dependent emission is observed both in the neat IL and in the IL+water mixture.

引用

页码：1770 / 1776

页数：7

共 92 条

[61] Excitation-wavelength-dependent fluorescence behavior of some dipolar molecules in room-temperature ionic liquids [J].