Cyanostilbene-Based Supramolecular Polymerization from One-Dimensional to Two-Dimensional Nanostructures via Photoreactions

Stilbene units are extensively used as supra-molecular polymer substructures and key light-responsive components whose structures and/or functions are control-lable via photochemical reactions. A stilbene unit was used to control the morphologies and properties of supramolecular polymerization via ultraviolet (UV) light. A cyanostilbene-based derivative revealed one-dimensional supramolecular polymerization with J-aggregates in methylcyclohexane, leading to a strong emission. Supramolecular polymerization follows the cooperative nucleation-elongation mechanism. Most importantly, the 1D supramolecular polymer was irradiated by UV light and underwent intermolecular [2 + 2] cycloaddition to produce a two-dimensional sheet structure. Additionally, the thermodynamic parameters of the UV-exposed aggregates were approximately 1.5-fold smaller than those of the nonexposed aggregates. These results demonstrate the utility of such stilbene-based aggregates in case of customizable supramolecular polymerization with UV light.