Symmetry-based rational design for boosting chiroptical responses

[摘要] Chiral molecules play indispensable roles in advanced materials and technologies. Nevertheless, no conventional, yet reliable logical strategies are available for designing chiral molecules of desired chiroptical properties. Here, we propose a general protocol for rationally aligning multiple chiral units to boost the chiroptical responses, using hexahelicene as a prototype. In this proof-of-concept study, we align two hexahelicenes in various orientations and examine by theoretical calculations to predict the best chiroptical performance for X-shaped and S-shaped double hexahelicenes. We synthesize and optically resolve both double hexahelicenes and show that they exhibit more than a twofold increase in intensity of circular dichroism and circularly polarized luminescence, experimentally validating the protocol. The enhanced chiroptical responses are theoretically assignable to the electric and magnetic transition dipole moments of component hexahelicenes aligned in the correct symmetry. A guiding principle for designing advanced molecular and supramolecular chiral materials is further discussed.

[学科分类] 化学工程（综合）