Jump to main content
Jump to site search

Issue 18, 2018
Previous Article Next Article

Effect of counter ions on the mesogenic ionic N-phenylpyridiniums

Author affiliations

Abstract

Two series of ionic liquid crystals (ILCs) derived from N-phenylpyridinium 1–2 were prepared and their mesomorphic properties were investigated. A versatile and effective method was developed to prepare these ionic compounds 2-X from their precursor chloride 2-Cl. X-ray crystal structure analyses of three single crystals revealed that a sandwiched head-to-head or bilayer lamellar structure induced by H-bonds in the solid state was observed. The anion was proximally intercalated near the head group. Weak H-bonds were induced and attributed to the formation of mesophases. The type of counter anions has a significant influence on the stability of the mesophase, ΔTSmA = 221.3 (2-Cl) > 213.1 (2-SCN) > 173.9 (2-BF4) > 85.4 (2-RSO3) > 63.8 (2-PF6) > 41.4 °C (2-OTf) for all derivatives with n = 12. The compound 2-BF4 (n = 16) has the widest temperature range of the smectic-A (SmA) phase (i.e., ΔTSmA = 234.3 °C), significantly broader than those of other reported ILCs. Also compound 2-NTf2 (n = 14) was the first phenylpyridinium-based ILC and compound 2-SCN (n = 16) was the room temperature ILC. The X-ray diffraction experiments confirmed the structure of the SmA phase and it showed a strong dependence of bilayer structure with various anions. A linear correlation plot (R2 = 0.9643) of the clearing temperatures of compounds 2-X with the calculated effective radius (Reff) of the anions was obtained.

Graphical abstract: Effect of counter ions on the mesogenic ionic N-phenylpyridiniums

Back to tab navigation

Supplementary files

Article information


Submitted
23 Feb 2018
Accepted
06 Apr 2018
First published
09 Apr 2018

CrystEngComm, 2018,20, 2593-2607
Article type
Paper

Effect of counter ions on the mesogenic ionic N-phenylpyridiniums

R. Wang, G. Lee and C. K. Lai, CrystEngComm, 2018, 20, 2593
DOI: 10.1039/C8CE00286J

Social activity

Search articles by author

Spotlight

Advertisements