From helices to superhelices through hierarchical assembly across competing pathways

Abstract

Understanding how molecular chirality propagates through competing self-assembly pathways remains a central challenge in supramolecular chemistry. We report a chiral π-conjugated quinquethiophene–rhodanine derivative forming four distinct and isolatable supramolecular aggregates from a single enantiomer under identical chemical conditions. These assemblies exhibit different chiroptical signatures, morphologies, hierarchical organization, and are selectively accessed through thermal and mechanical treatment. Calorimetry enables the experimental construction of the energy landscape, while long-term kinetic studies and spectral deconvolution reveal interconversions between helical structures, identifying an off-pathway hierarchical state. Remarkably, the most stable structure forms through a helix-to-superhelix transition governed by secondary nucleation. Cross-seeding experiments demonstrate that different dimensionality assemblies accelerate transformations across hierarchical levels, revealing an unusually interconnected assembly network. These results provide an experimental example where multiple supramolecular structures, their thermodynamic ordering, and kinetic connectivity are established within a single molecular system, showing how pathway selection programs chirality, hierarchy, and morphology in supramolecular materials. Understanding how molecular chirality propagates through competing self-assembly pathways to generate hierarchical structures remains a central challenge in supramolecular chemistry. Here the authors report a chiral π-conjugated quinquethiophene–rhodanine derivative that forms four distinct and isolatable supramolecular aggregates from a single enantiopure monomer under identical chemical conditions.