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  • Dicationic ionic liquid crystals: Synthesis, characterization, optical properties, and ionic conductivity of bis(4-oligoethyleneoxyphenyl) viologen bistosylate salts
Title: Dicationic ionic liquid crystals: Synthesis, characterization, optical properties, and ionic conductivity of bis(4-oligoethyleneoxyphenyl) viologen bistosylate salts
ree bis(4-oligoethyleneoxyphenyl) viologen bistosylate salts of different lengths were prepared via the Zincke reaction followed by a metathesis reaction with silver tosylate, and their chemical structures confirmed by 1H, 13C nuclear magnetic resonance (NMR), Fourier transform infrared (FTIR) techniques, and elemental analysis. Thermogravimetric analysis (TGA) showed these salts had excellent thermal stabilities, losing just 5 % of their initial mass between 283 and 288 °C. Liquid crystalline phases and transition temperatures were determined by differential scanning calorimetry (DSC), polarizing optical microscopy (POM), and variable temperature X-ray diffraction (VTXRD) techniques. The salts exhibited weak fluorescent emission in dichloromethane and no emission in acetonitrile but exhibited light emission in the solid state. Their absolute quantum yields ranged between 3 and 12 %. Impedance spectroscopy showed that the ionic conductivity of the salts increases with the number of oxyethylene units in the extended viologen moiety. The salt-containing four oxyethylene units at each end reach a conductivity value of 10-2 S·cm−1, attributed to its larger molecular flexibility and improved ionic liquid mobility.  more » « less
Award ID(s):
2211347
PAR ID:
10513465
Author(s) / Creator(s):
; ; ; ; ; ; ; ; ;
Publisher / Repository:
Elsevier
Date Published:
Journal Name:
Journal of Molecular Liquids
Edition / Version:
1
Volume:
398
Issue:
C
ISSN:
0167-7322
Page Range / eLocation ID:
124140
Subject(s) / Keyword(s):
Ionic liquid crystals Differential scanning calorimetry Polarized optical microscopy Variable temperature X-ray diffraction Ionic conductivity Dielectric spectroscopy
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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