Driving Helical Packing of a Cyanine Dye on Dendron Nanofiber: Gel-Shrinkage-Triggered Chiral H-Aggregation and Enhanced Enantiodiscrimination.

An intelligent molecular hydrogel with a volume phase transition was constructed to regulate the chiral packing of a well-known cyanine dye on a dynamically self-assembled chiral nanofiber by using a pH trigger. During the shrinkage of the gel, the chiral nanofiber hierarchically assembled into a superhelix and simultaneously drove the dye molecules to stack, from a predominantly monomer form, in an unexpected helical H-aggregation manner. Through such a transformation, the supramolecular chirality of the system was significantly enhanced and a new property of visual discrimination for chiral amines emerged.