In Situ Heterochiral Helix Coupling Triggered Supramolecular Evolution

Area of Science:

• Supramolecular Chemistry
• Chiral Materials Science
• Biostructure Evolution

Background:

• Precise matching of chiral structures is crucial for directing biostructure evolution.
• Current methods for creating stereoselective pairs rely on static self-assembly.
• Dynamically controlling helix coupling for structure evolution remains a significant challenge due to complex chirality transfer.

Purpose of the Study:

• To introduce stereochemical strategies for controlling heterochiral helix coupling (P and M helices).
• To enable the evolution of primary nanofibers into advanced superstructures.
• To investigate mechanisms of chirality transfer in racemic and meso-systems.

Main Methods:

• Employing stereochemical strategies: homochirality to racemization or mesomerization.
• Utilizing in situ generated heterochiral P-M helix coupling via spatially matched hydrogen bonds.
• Analyzing chirality transfer mechanisms, including bifurcated transfer in racemic systems facilitated by CH···π interactions.

Main Results:

• Homochiral systems remained as nanofibers without evolution for over a year.
• Racemization and mesomerization strategies triggered evolution to superstructures within 7 hours and 12 months, respectively.
• Racemic systems exhibited a rare bifurcated chirality transfer mechanism, unlike unidirectional transfer in meso-systems.

Conclusions:

• Stereochemical control over heterochiral helix coupling is a viable strategy for directing biostructure evolution.
• The developed strategies enable dynamic control over the formation of complex helical superstructures.
• Understanding chirality transfer mechanisms is key to designing advanced self-assembling chiral materials.