Tracking Electrons In Ionic Liquids

Ionic liquids are hot in applications such as energy storage and recycling spent nuclear fuel, both of which involve exposing the liquids to electronic processes. But little is known about the interactions of the liquids with electrons. A research group led by Claudio J. Margulis of the University of Iowa has used quantum molecular dynamics simulations to study what happens in the first few picoseconds after an electron is injected into liquids likely to be used for such applications (J. Am. Chem. Soc. 2013, DOI: 10.1021/ja409338z). The group specifically studied alkylammonium- and pyrrolidinium-based ionic liquids containing bis(trifluoromethylsulfonyl)amide anion. They found that the electron is initially delocalized over several anions and moves among sets of anions. Over the course of 50 femtoseconds, the electron becomes localized onto one anion and initiates the ion’s fragmentation, likely by breaking a bond between nitrogen and sulfur. Better understanding of these processes will help researchers determine which ionic liquids would best resist electron-induced degradation and provide a more detailed picture of electron-transfer reactions in ionic liquid systems, Margulis says.