Clusters of imidazolium-based ionic liquid in benzene solutions
Takuya Shimomura1, Toshiyuki Takamuku, Toshio Yamaguchi
1Department of Chemistry and Applied Chemistry, Graduate School of Science and Engineering, Saga University, Honjo-machi, Saga, Japan.
The Journal of Physical Chemistry. B
|June 2, 2011
Summary
Clusters of 1-dodecyl-3-methylimidazolium bis(trifluoromethanesulfonyl)amide (C(12)mim(+)TFSA(-)) form in benzene solutions. These clusters, driven by cation-π interactions, explain the liquid-liquid equilibrium observed in this ionic liquid-aromatic solvent system.
Area of Science:
- Materials Science
- Physical Chemistry
- Supramolecular Chemistry
Background:
- Ionic liquids (ILs) exhibit unique solvation properties.
- Understanding IL-solvent interactions is crucial for their applications.
- Phase behavior of ILs in organic solvents influences their utility.
Purpose of the Study:
- To investigate the cluster formation of 1-dodecyl-3-methylimidazolium bis(trifluoromethanesulfonyl)amide (C(12)mim(+)TFSA(-)) in benzene solutions.
- To elucidate the molecular interactions driving these clusters.
- To explain the observed liquid-liquid equilibrium in the C(12)mim(+)TFSA(-)-benzene system.
Main Methods:
- Small-angle neutron scattering (SANS) for heterogeneity analysis.
- Nuclear Magnetic Resonance (NMR) for molecular interactions.
- Attenuated total reflectance infrared (ATR-IR) spectroscopy.
- Large-angle X-ray scattering (LAXS) for structural insights.
Main Results:
- Heterogeneous mixing of C(12)mim(+)TFSA(-) and benzene observed in a specific mole fraction range (0.9 ≤ x(C6D6) ≤ 0.995).
- NMR suggests cation-π interactions between the imidazolium ring and benzene molecules.
- LAXS indicates specific distances between imidazolium rings and benzene molecules (~3.8 Å).
Conclusions:
- C(12)mim(+)TFSA(-) and benzene form clusters driven by cation-π interactions and TFSA(-) interactions with the imidazolium ring.
- These cluster formations provide a plausible explanation for the liquid-liquid equilibrium in the C(12)mim(+)TFSA(-)-benzene system.
- The study highlights the complex self-assembly behavior of ionic liquids in aromatic solvents.
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