Ionic liquid crystals based on 1-alkyl-3-methylimidazolium cations and perfluorinated sulfonylimide anions
摘要:
In contrast to the studies on ionic liquids based on perfluorinated sulfonylimide anions, their ionic liquid crystals were seldom reported. In the present study, four 1-alkyl-3-methylimidazolium perfluorinated sulfonylimide salts ([C(x)MIm][N(SO2RF)(2)], x = 18 and 22; R-F = F (FSI) and CF3(TFSI)) have been synthesized and characterized. [C(22)MIm][FSI], [C(18)MIm][FSI], and [C(22)MIm][TFSI] show smectic A(2) liquid crystalline mesophase. Single-crystal XRD revealed that [C(18)MIm][FSI] and [C(22)MIm][TFSI] show layered structures of low-polar and high-polar layers alternate with each other in the crystalline phase. It is suggested that perfluorinated sulfonylimide anions have relatively weak coulomb interactions with imidazolium headgroups, making them relatively difficult to form mesophase. (C) 2015 Elsevier B.V. All rights reserved.
The Fluid-Mosaic Model, Homeoviscous Adaptation, and Ionic Liquids: Dramatic Lowering of the Melting Point by Side-Chain Unsaturation
作者:Samuel M. Murray、Richard A. O'Brien、Kaila M. Mattson、Christopher Ceccarelli、Richard E. Sykora、Kevin N. West、James H. Davis
DOI:10.1002/anie.200906169
日期:2010.4.1
Defying conventional wisdom: Ionicliquids (ILs) with long, unsaturated alkyl appendages (see top structure) defy established trends that link long ion‐bound alkyl groups to higher melting points. The new ILs are also less viscous than a saturated standard (see bottom structure) at the same temperature. These features parallel those that underpin homeoviscousadaptation in certain organisms and are