Ionic liquid crystals: Synthesis and characterization via NMR, DSC, POM, X-ray diffraction and ionic conductivity of asymmetric viologen bistriflimide salts

A series of asymmetric viologen bistriflimide salts both short and long alkyl chains were synthesized by the metathesis reaction lithium triflimide salt with respective dibromide in methanol. Their thermotropic liquid crystalline properties determined differential scanning calorimetry, polarizing optical microscopy variable temperature X-ray diffraction techniques. These melt into highly-ordered smectic T phases that is, crystal-to SmT transitions (T m s) at relatively low temperatures (lowest ?12 °C) maintain crystallinity a wide range (8–132 °C), excellent thermal stabilities up to 320 °C as thermogravimetric analysis. results differ respect symmetric salts. Ionic conductivity these was also measured dielectric impedance spectroscopy found be 10 ?2.5 S cm ?1 range, highlighting their potential electrolytes room temperature. • Synthesis performed reaction. liquid-crystalline experimental They transformed temperatures. showed liquid-crystallinity broad ionic –2.5 range.