Tunable Chiroptical Switching via 2-Fold Chiral Conflict in Statistical Racemic Copolymer Assemblies

Chiral communication between mirror-imaged enantiomers is important for the development of homochirality in nature. However, polymers made from racemic mixtures usually show no chiroptical activity. Here, we present a new strategy to create global chirality in statistical racemic copolymers and to switch their chiroptical activity using a 2-fold chiral conflict. Chiroptically active assemblies consisting of racemic building units within two heterochiral segments were constructed via a stepwise statistical polymerization-induced chiral self-assembly (stat-PICSA) method. Furthermore, the stacking patterns and resulting chiroptical activity could be switched by changing the ratio of enantiomeric monomers. This switching exhibited distinct chiral conflict effects: "first come, first served" (FF)/"late-comer lives above" (LA) chiral conflict effects. We expect this 2-fold chiral conflict self-assembly strategy to offer a unique approach for developing chiroptical racemic polymer nanoassemblies and to deepen our understanding of how homochiral structures originate in nature.