Eccentrically Twisted and Helical Nanoarchitectonics by Sequence-Defined Peptide-π Conjugates

Peptide self-assembly presents a powerful strategy for constructing chiral nanostructures with promising applications in biology and materials science. Here, we demonstrate the precise control over helical nanostructures through sequence-specific dipeptide-naphthalenediimide (NDI) conjugates. Two enantiomeric pairs of NDI derivatives, bearing either glycyl-L/D-leucine (Gly-Leu) or L/D-leucyl-glycine (Leu-Gly) sequences, were assembled in methanol/water and dimethylformamide/water mixed solvents. Strikingly, the Gly-Leu-functionalized derivatives (NDI-Gly-Leu) exhibited sequence-dependent chirality expression, forming eccentric twists and helices with significantly amplified chiroptical signals, while the NDI-Leu-Gly did not. We propose the "radius of torsion" to quantitatively describe the helicity of the nanostructures and correlate with their optical activity for the first time. We further revealed the generation of chiral NDI^•- radical anions from NDI derivatives, which also showed the sequence-defined assembly effect. These insights deepen the fundamental understanding of peptide-directed chiral self-assembly and open new avenues for designing functional chiral nanomaterials.