Anion driven ionic liquid crystals: The effect of the connecting group in [closo-1-CB₉H₁₀]^- derivatives on mesogenic properties

Abstract

Replacement of the connecting CH₂ group in ionic liquid crystal 1a[Pyr] with an oxygen atom in 1b[Pyr] resulted in significant destabilisation of the nematic and, to a greater extent, smectic A (SmA) phases, as established from binary mixture studies in 2a[Pyr]. Density functional theory (DFT) modelling of both anions suggests that the destabilisation results from the difference in charge distribution rather than conformational changes. Binary mixture studies demonstrated that all three ionic liquid crystals are compatible with a non-ionic benzoate nematic host 3a.

Keywords:

• ionic liquid crystals
• boron clusters
• synthesis

Acknowledgements

Financial support for this work was received from the National Science Foundation (DMR-0907542). We thank Mr Bryan Ringstrand for help with the attempted preparation of acid 5c[NMe₄].