Dry Excess Electrons in Room-Temperature Ionic Liquids

Claudio J. Margulis, Harsha V. R. Annapureddy, Pablo M. De Biase, David Coker, Jorge Kohanoff, Mario G. Del Popolo

Research output: Contribution to journalArticlepeer-review

33 Citations (Scopus)
280 Downloads (Pure)

Abstract

In this article, we describe general trends to be expected at short times when an excess electron is generated or injected in different room-temperature ionic liquids (RTILs). Perhaps surprisingly, the excess electron does not localize systematically on the positively charged cations. Rather, the excess charge localization pattern is determined by the cation and anion HOMO/LUMO gaps and, more importantly, by their relative LUMO alignments. As revealed by experiments, the short-time (ps/ns) transient UV spectrum of excess electrons in RTILs is often characterized by two bands, a broad band at low energies (above 1000 nm) and another weaker band at higher energies (around 400 nm). Our calculations show that the dry or presolvated electron spectrum (fs) also has two similar features. The broad band at low energies is due to transitions between electronic states with similar character on ions of the same class but in different locations of the liquid. The lower-intensity band at higher energies is due to transitions in which the electron is promoted to electronic states of different character, in some cases on counterions. Depending on the chemical nature of the RTIL, and especially on the anions, excess electrons can localize on cations or anions. Our findings hint at possible design strategies for controlling electron localization, where electron transfer or transport across species can be facilitated or blocked depending on the alignment of the electronic levels of the individual species.
Original languageEnglish
Pages (from-to)20186-20193
Number of pages8
JournalJournal of the American Chemical Society
Volume133
Issue number50
Early online date27 Oct 2011
DOIs
Publication statusPublished - 21 Dec 2011

ASJC Scopus subject areas

  • Chemistry(all)
  • Catalysis
  • Biochemistry
  • Colloid and Surface Chemistry

Fingerprint Dive into the research topics of 'Dry Excess Electrons in Room-Temperature Ionic Liquids'. Together they form a unique fingerprint.

Cite this