The Coiling Effect in Ether Ionic Liquids: Exploiting Acetate as a Probe for Transport Properties and
Beatriz R de Moraes1, Vitor H Paschoal1, Nicolas Keppeler2
1Laboratório de Espectroscopia Molecular, Departamento de Química Fundamental, Instituto de Química, Universidade de São Paulo, São Paulo 05508-900, Brazil.
The Journal of Physical Chemistry. B
|April 12, 2024
Summary
Ether functionalization significantly improves ionic liquid fluidity by reducing viscosity. This study explores structure-property relationships and anion- A cation interactions in ether-based ionic liquids.
Area of Science:
- Materials Science
- Physical Chemistry
- Computational Chemistry
Background:
- High viscosity of ionic liquids (ILs) hinders their practical applications.
- Modifying cation side chains with ether groups is a strategy to enhance IL fluidity.
- Understanding structure-property relationships is crucial for designing improved ILs.
Purpose of the Study:
- To investigate the structure-property relationship of ionic liquids with ether-functionalized cations and acetate anions.
- To elucidate the effect of ether groups on IL viscosity, thermal stability, and microstructure.
- To analyze the interaction between acetate anions and ether-functionalized ionic liquids.
Main Methods:
- Synthesis and characterization of ionic liquids with varying cation side chains (alkyl, ether, hydroxyl).
- Experimental evaluation of viscosity, thermal stability using spectroscopy (Raman, IR).
- Computational analysis using density functional theory (DFT) and ab initio molecular dynamics (AIMD) simulations.
Main Results:
- Ether insertion in cation side chains significantly reduces IL viscosity, attributed to a cation coiling effect.
- Acetate anions exhibit bidentate coordination with ether ILs, enhanced by hydrogen bonding in hydroxyl-functionalized ILs.
- Spectroscopic and simulation data reveal weaker acetate-imidazolium ring interactions and intramolecular hydrogen bonding in ether ILs.
Conclusions:
- Ether functionalization is an effective strategy to enhance ionic liquid fluidity.
- The coordination behavior of acetate anions is influenced by ether and hydroxyl groups on the cation.
- Combined experimental and theoretical approaches provide comprehensive insights into ionic liquid behavior.
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