Isomeric Effects on Supramolecular Polymerization of Hexaazatrinaphthylene Derivatives

Supramolecular polymers based on electron-deficient n-type organic semiconductors are promising candidates for organic electronic applications. Hexaazatrinaphthylene (HATNA) is particularly attractive due to its high charge-carrier mobility and redox activity. However, the impact of molecular symmetry on its supramolecular polymerization remains underexplored. Here, we compare two constitutional isomers of amide-functionalized HATNA derivatives: a C₃-symmetric (C₃-HATNA) and a C₁-symmetric (C₁-HATNA) variant. Although both isomers exhibit similar electrochemical and optical properties in solution, their supramolecular polymerization leads to markedly different structural organizations. Spectroscopic, microscopic, scattering, and computational studies reveal that C₃-HATNA forms tightly packed assemblies, consistent with stronger and more directional hydrogen bonding. In contrast, the reduced symmetry of C₁-HATNA leads to less directional hydrogen bonding and asymmetric solvent exposure of the core, promoting bundling and the formation of longer fibers. These findings highlight the role of molecular symmetry in directing assembly pathways and provide insights for designing supramolecular materials for organic electronics.