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Article
Dynamic Solvation in Room-Temperature Ionic Liquids
Journal of Physical Chemistry B
  • Pramit Kumar Chowdhury, Iowa State University
  • Mintu Halder, Iowa State University
  • L. Sanders, Iowa State University
  • T. Calhoun, Iowa State University
  • Jared L. Anderson, Iowa State University
  • Daniel W. Armstrong, Iowa State University
  • Xueyu Song, Iowa State University
  • Jacob W. Petrich, Iowa State University
Document Type
Article
Publication Version
Published Version
Publication Date
6-2-2004
DOI
10.1021/jp0376828
Abstract

The dynamic solvation of the fluorescent probe, coumarin 153, is measured in five room-temperature ionic liquids using different experimental techniques and methods of data analysis. With time-resolved stimulated-emission and time-correlated single-photon counting techniques, it is found that the solvation is comprised of an initial rapid component of ∼55 ps. In all the solvents, half or more of the solvation is completed within 100 ps. The remainder of the solvation occurs on a much longer time scale. The emission spectra of coumarin 153 are nearly superimposable at all temperatures in a given solvent unless they are obtained using the supercooled liquid, suggesting that the solvents have an essentially glassy nature. The physical origin of the two components is discussed in terms of the polarizability of the organic cation for the faster one and the relative diffusional motion of the cations and the anions for the slower one. A comparison of the solvation response functions obtained from single-wavelength and from spectral-reconstruction measurements is provided. Preliminary fluorescence-upconversion measurements are presented against which the appropriateness of the single-wavelength method for constructing solvation correlation functions and the use of stimulated-emission measurements is considered. These measurements are consistent with the trends mentioned above, but a comparison indicates that the presence of one or more excited states distorts the stimulated-emission kinetics such that they do not perfectly reproduce the spontaneous emission data. Fluorescence-upconversion results indicate an initial solvation component on the order of ∼7 ps.

Comments

Reprinted (adapted) with permission from Journal of Physical Chemistry B, 108 (2004): 10245, doi: 10.1021/jp0376828. Copyright 2004 American Chemical Society.

Copyright Owner
American Chemical Society
Language
en
File Format
application/pdf
Citation Information
Pramit Kumar Chowdhury, Mintu Halder, L. Sanders, T. Calhoun, et al.. "Dynamic Solvation in Room-Temperature Ionic Liquids" Journal of Physical Chemistry B Vol. 108 Iss. 29 (2004) p. 10245 - 10255
Available at: http://works.bepress.com/jared_anderson/21/