Superhelical Self-Assembly of Microcrystals from Cyclodipeptides

Area of Science:

• Supramolecular Chemistry
• Materials Science
• Organic Chemistry

Background:

• Macroscopic chirality expression is crucial for advanced materials.
• Bottom-up assembly offers a pathway to complex superstructures.
• Controlling hierarchical organization is key for functional materials.

Purpose of the Study:

• To present a cyclodipeptide platform for macroscopic chirality expression.
• To investigate the self-assembly pathway of cyclodipeptides into helical superstructures.
• To explore the potential of these helical structures in chiral materials and optics.

Main Methods:

• Synthesis of homochiral linear dipeptides (tyrosine and phenylglycine).
• Cyclization to form cyclodipeptides.
• In situ reaction-induced aggregation and self-assembly into helical superstructures.

Main Results:

• Achieved ultra-high yields and phase purity of giant helices.
• Identified a novel folded cyclodipeptide geometry forming 2D hydrogen-bonded networks.
• Demonstrated chirality transfer and strong circularly polarized luminescence in the helical structures.

Conclusions:

• The cyclodipeptide platform effectively expresses chirality at the macroscopic level.
• The self-assembly pathway involves microcrystal formation and dislocation-mediated assembly.
• These chiral superstructures show promise for applications in optics and chiral materials.