Photo-Responsive Chiral Supramolecular Polymers Based on C₃-Symmetric Triphenylene Triimides

A new type of C₃-symmetric triphenylene triimides (TTI) bearing different oligo(ethylene glycol) side chains via imide linkages is developed in this study. By exploiting this unique TTI molecule as a building block, a supramolecular polymerization is explored on the basis of π-π stacking and hydrophilic/hydrophobic interaction depending on the type of solvents and rates of heating/cooling process. The molecular chirality of TTI monomer triggers the formation of a preferential helicity in fibrous structures. The stacking type of supramolecular polymerization is highly dependent on the presence of the point chirality of side chains, as evidenced by a collection of spectroscopic analyses including UV/vis and CD spectroscopy together with AFM, TEM, and WAXS. Interestingly, while the fibrous structure in assembled state is maintained due to the intermolecular interaction, the self-assembly does not occur in monomeric state due to the formation of radical anion of imide groups under UV irradiation. This study is anticipated to provide a new direction in the control of the supramolecular chiral assembly.