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Article
Influence of the Counteranion on the Ability of 1-Dodecyl-3-methyltriazolium Ionic Liquids to Form Mesophases
Crystal Growth & Design
  • Kathrin Stappert, Ruhr-Universitat Bochum
  • Derya Unal, Ruhr-Universitat Bochum
  • Eike T. Spielberg, Ruhr-Universitat Bochum
  • Anja V. Mudring, Iowa State University
Document Type
Article
Publication Version
Published Version
Publication Date
1-1-2015
DOI
10.1021/cg501564j
Abstract

The influence of the counteranion on the ability of the mesogenic cation 1-methyl-3-dodecyl-triazolium to form mesophases is explored. To that avail, salts of the cation with anions of different size, shape, and hydrogen bonding capability such as Cl–, Br–, I–, I3–, PF6–, and Tf2N– [bis(trifluorosulfonyl)amide] were synthesized and characterized. The crystal structures of the bromide, the iodide, and the triiodide reveal that the cations form bilayers with cations oriented in opposite directions featuring interdigitated alkyl tails. Within the layers, the cations are separated by anions. The rod-shaped triiodide anion forces the triazolium cation to align with it in this crystal structure but due to its space requirement reduces the alkyl chain interdigitation which prevents the formation of a mesophase. Rather the compound transforms directly from a crystalline solid to an (ionic) liquid like the analogous bis(trifluorosulfonyl)amide. In contrast, the simple halides and the hexafluorophosphate form liquid crystalline phases. Their clearing points shift with increasing anion radius to lower temperatures.

Comments

Reprinted with permission from Cryst. Growth Des., 2015, 15 (2), pp 752–758. Copyright 2014 American Chemical Society.

Copyright Owner
American Chemical Society
Language
en
File Format
application/pdf
Citation Information
Kathrin Stappert, Derya Unal, Eike T. Spielberg and Anja V. Mudring. "Influence of the Counteranion on the Ability of 1-Dodecyl-3-methyltriazolium Ionic Liquids to Form Mesophases" Crystal Growth & Design Vol. 15 Iss. 2 (2015) p. 752 - 758
Available at: http://works.bepress.com/anja_mudring/5/