Abstract
In this article we determine the temperature-dependent structure of the tetradecyltrihexylphosphonium bis(trifluoromethylsulfonyl)amide ionic liquid using a combination of X-ray scattering and molecular dynamics simulations. As in many other room-temperature ionic liquids three characteristic intermolecular peaks can be detected in the structure function S(q). A prepeak or first sharp diffraction peak is observed at about q = 0.42 Å -1. Long range anion-anion correlations are the most important contributors to this peak. In all systems we have studied to date, this prepeak is a signature of solvation asymmetry. The peak in S(q) near q = 0.75 Å -1 is the signature of ionic alternation and arises from the charge ordered separation of ions of the same charge. The most intense diffraction peak near q = 1.37 Å -1 arises from short-range separation between ions of opposite charge combined with a significant contribution from cationic carbon-carbon interactions, indicating that cationic hydrophobic tails have significant contacts.
Original language | English |
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Pages (from-to) | 133-143 |
Number of pages | 11 |
Journal | Faraday Discussions |
Volume | 154 |
DOIs | |
Publication status | Published - 2012 |
ASJC Scopus subject areas
- Physical and Theoretical Chemistry