Captodative Radicals Coupling Into Homochiral Molecular Nanotubes With Conglomerate Crystallization

Area of Science:

• Supramolecular Chemistry
• Organic Chemistry
• Materials Science

Background:

• Chiral macrocycles are crucial for enantioselective recognition and asymmetric catalysis.
• Designing and synthesizing novel chiral macrocyclic architectures remains a significant challenge.

Purpose of the Study:

• To construct an unprecedented homochiral molecular nanotube via self-assembly.
• To explore the stimuli-responsive properties and electrochemical behavior of the novel macrocycle.

Main Methods:

• Achiral C2-symmetric semirigid monomers with dicyanomethyl radicals were synthesized.
• Reversible radical coupling was employed for self-assembly into a trimeric macrocycle.
• X-ray crystallography, circular dichroism (CD) spectroscopy, and electrochemical methods were used for characterization.

Main Results:

• An unprecedented homochiral molecular nanotube (1) was successfully constructed through narcissistic chiral self-assembly.
• The nanotube formation transferred conformational chirality from achiral monomers to the macrocycle, yielding homochirality.
• Racemic 1 exhibited conglomerate crystallization into enantiomers, and the dynamic radical bonds imparted solvent- and thermal-responsive properties.

Conclusions:

• A new method for creating stimuli-responsive chiral macrocycles using radical-mediated dynamic covalent chemistry was established.
• The self-assembled homochiral nanotube demonstrates potential applications in enantioselective processes.
• The study offers a novel paradigm for designing complex chiral supramolecular structures.