Liquid-Crystalline Ionic Liquids as Ordered Reaction Media for the Diels–Alder Reaction

John Martin Slattery, Duncan Watson Bruce, Yanan Gao, Karina Shimizu, Jose Nuno Canongia Lopes

Research output: Contribution to journalArticlepeer-review

Abstract

Liquid-crystalline ionic liquids (LCILs) are ordered materials that have untapped potential to be used as reaction media for synthetic chemistry. This paper investigates the potential for the ordered structures of LCILs to influence the stereochemical outcome of the Diels–Alder reaction between cyclopentadiene and methyl acrylate. The ratio of endo- to exo-product from this reaction was monitored for a range of ionic liquids (ILs) and LCILs. Comparison of the endo:exo ratios in these reactions as a function of cation, anion and liquid crystallinity of the reaction media, allowed for the effects of liquid crystallinity to be distinguished from anion effects or cation alkyl chain length effects. These data strongly suggest that the proportion of exo-product increases as the reaction media is changed from an isotropic IL to a LCIL. A detailed molecular dynamics (MD) study suggests that this effect is related to different hydrogen bonding interactions between the reaction media and the exo- and endo-transition states in solvents with layered, smectic ordering compared to those that are isotropic.
Original languageEnglish
Pages (from-to)16113–16123
Number of pages11
JournalChemistry : A European Journal
Volume22
Issue number45
Early online date23 Sept 2016
DOIs
Publication statusPublished - 2 Nov 2016

Bibliographical note

© 2016, Wiley-VCH Verlag GmbH & Co. K. This is an author-produced version of the published paper. Uploaded in accordance with the publisher’s self-archiving policy. Further copying may not be permitted; contact the publisher for details.

Keywords

  • DIELS-ALDER
  • IONIC LIQUID
  • LIQUID CRYSTAL
  • MOLECULAR DYNAMICS
  • Ordered Solvents

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