First Gemini-type fluorescent ionic liquid crystals: Synthesis, fluorescence emission and self-assembly in liquid crystals and gels

Although many Gemini-type ionic liquids crystals (ILCs) had been studied, the Gemini-type fluorescence ionic liquid was not presented so far. In this work, the first Gemini-type fluorescence ILCs based on dicyanodivi-nylbenzene unit and imidazole cations with -CH3, -C4H9 and -C6H13 chains were prepared. They emitted strong fluorescence in aggregated states based on the aggregation-induced emission effect. They displayed the reversible smectic mesophase in wide scope of temperature. Furthermore, the stable gels in DMSO-toluene (1:1) system were observed for these new ILCs and the gels possessed the excellent thermal reversible response. The novel ionic liquid with C6H13 chains presented the orderly rectangular columnar stacking in gel. The CVs studies suggested that these Gemini-type fluorescence ILCs possessed the stable electrochemical properties. This research not only reported the first Gemini-type ILCs bearing high fluorescence, good liquid crystalline and gel properties, but also presented a unique self-assembled change from a coated mesophase in liquid crystal to a rectangular columnar stacking in gel.

Automated summary

In this study, Gemini-type fluorescence ionic liquid crystals (ILCs) were prepared and investigated. These ILCs emitted strong fluorescence in aggregated states and exhibited reversible smectic mesophase. The stable gels formed in DMSO-toluene system showed excellent thermal reversible response. The novel ILCs with C6H13 chains presented orderly rectangular columnar stacking in the gel phase.