Enhancing Optical Activities of Benzimidazole Derivatives through Coassembly for High-Efficiency Synthesis of Chiroptical Nanomaterials and Accurate ee % Detection of Natural Acids.

Developing efficient protocols to enhance the optical activities of chiral self-assemblies is a key to realizing their chiroptical functions such as chiral sensing and displays. Here, we have reported a coassembly protocol to efficiently boost the chiroptical responses, whereby the synthesis of chiroptical nanomaterials and highly accurate detection of enantiomeric excess (ee %) were achieved. A series of benzimidazole derivatives with different topologies underwent spontaneous aggregation and symmetry breaking in solution, generating silent Cotton effects, yet exclusive weak left-handed circularly polarized luminescence (CPL). The coassembly with natural hydroxyl acids via complementary H bonds afforded chiral nanostructures with emerged Cotton effects and enhanced CPL. Dissymmetry g-factors were dramatically boosted (glum from 1 × 10-3 to 5.5 × 10-2, gabs from 0 to 6.7 × 10-3). In addition, proof of concept of recognition and detection of natural chiral molecules was realized with high accuracy.