Ion-Pairing Chromonic Liquid Crystals via Alternately Stacked Assembly of Amphiphilic Charged π-Electronic Systems.

In this study, a new assembly strategy for lyotropic chromonic liquid crystals (LCLCs) is proposed using π-π interactions, mainly comprising electrostatic and dispersion forces, between charged π-electronic systems to form stacking structures supported by the hydration of triethylene glycol (TEG) units. The meso-TEG-aryl-substituted porphyrin Au complex, an amphiphilic π-electronic cation, showed diverse states and assembly modes in ion pairs depending on the coexisting counteranions. The PCCp ion pair formed a hexagonal columnar (Col) LC phase based on a charge-by-charge assembly, suggesting the formation of an ordered arrangement of charged π-electronic systems through π-π interactions, with reduced interactions between the TEG chains. Furthermore, in the presence of water, LCLC behavior in the Col and nematic columnar phases according to the amount of water were observed for the PCCp ion pair as a result of π-π interactions. Magnetic-field-induced orientation of the charge-by-charge columnar structures upon dehydration was observed. Furthermore, single-stranded charge-by-charge columnar structures, as components of the LCLCs, were observed using transmission electron microscopy (TEM).