Supramolecular Polymerization and Polymorphs of Oligo(p-phenylene vinylene)-Functionalized Bis- and Monoureas

Bis‐ and monoureas hybridized with the oligo(p‐phenylene vinylene) (OPV) π‐electronic segment and 3,4,5‐tridodecyloxyphenyl wedge were synthesized and their supramolecular polymerization in diluted solution, gel formation in concentrated solution, and liquid crystallinity in bulk state were investigated. Bisurea 1 a featuring a hexamethylene linker showed the highest supramolecular polymerization ability and formed tapelike nanofibers that can gelate various organic solvents. On the other hand, bisurea 1 b featuring a dodecamethylene linker and monourea 2 showed a lower degree of supramolecular polymerization, resulting in gel formations in a smaller variety of solvents. These results clearly reflect a high level of cooperativity between the two urea sites and the two OPV segments of 1 a upon hydrogen‐bonding and π–π stacking interactions, respectively. When the gels of 1 a, 1 b, and 2 were dried, all the compounds self‐organized into multilamellar superstructures. Thermal treatment of these lamellae at high temperatures induces columnar liquid‐crystalline mesophases as a result of microsegregation between the rigid OPV parts and the molten aliphatic wedges. These results demonstrate that the present molecular constituent is very useful for fabricating dye‐based functional assemblies providing nanoscale π‐electronic fibers, and solvent‐incorporated and bulk soft materials. Supramolecular polymers: Oligo(p‐phenylene vinylene)‐functionalized bis‐ and monourea compounds are shown to form a variety of material morphologies involving nanoscale supramolecular tapes, fluorescent organogels, and liquid crystals (see graphic).