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Room temperature ionic liquids with two symmetric ions.

Daniel RauberFrederik PhilippiDaniel SchroederBernd MorgensternAndrew J P WhiteMarlon JochumTom WeltonChristopher W M Kay
Published in: Chemical science (2023)
Room temperature ionic liquids typically contain asymmetric organic cations. The asymmetry is thought to enhance disorder, thereby providing an entropic counter-balance to the strong, enthalpic, ionic interactions, and leading, therefore, to lower melting points. Unfortunately, the synthesis and purification of such asymmetric cations is typically more demanding. Here we introduce novel room temperature ionic liquids in which both cation and anion are formally symmetric. The chemical basis for this unprecedented behaviour is the incorporation of ether-containing side chains - which increase the configurational entropy - in the cation. Molecular dynamics simulations indicate that the ether-containing side chains transiently sample curled configurations. Our results contradict the long-standing paradigm that at least one asymmetric ion is required for ionic liquids to be molten at room temperature, and hence open up new and simpler design pathways for these remarkable materials.
Keyphrases
  • ionic liquid
  • room temperature
  • molecular dynamics simulations
  • high resolution
  • solid state
  • molecular docking
  • minimally invasive
  • quantum dots
  • mass spectrometry
  • aqueous solution