Dynamically Folded Chiral Arms for Selectively Clamping Aromatic Imides.

Peptide-based folding systems have intriguing features with a variety of advanced applications. Rational and precise control over their dynamic folding behaviors and exploring the role in recognition of guests are conducive to construct adaptive molecular machines and host-guest chemistry. In this work, peptide arms were conjugated on the benzothiophene skeleton with a rotatable axis with terminated pyrene as luminescent signaling domains. The folding behaviors show adaptiveness toward solvation that impacts the expression on chirality and chiroptical properties by which the circularly polarized luminescence can be initiated. Beyond the signaling, pyrene domains function as chiral clamps to include aromatic imides by charge-transfer interaction with high selectivity. The size of the aromatic planes, steric effects, and electron deficiency determined the binding affinity. Supramolecular clamping of aromatic imides would disassociate the aggregation into complexes that invert the chirality. The study advances the design of flexible chiral molecular systems with applications in host-guest chemistry and chiroptical sensing.