Thermally Controlled Chiral Supramolecular Polymorphism in Water

Area of Science:

• Supramolecular Chemistry
• Materials Science
• Chiral Chemistry

Background:

• Biological assemblies exhibit stimulus-responsive morphological changes.
• Controlled polymorphic transitions in synthetic chiral supramolecular systems are not well understood.
• Developing synthetic analogues that mimic biological adaptability is crucial.

Purpose of the Study:

• To demonstrate controlled chiral supramolecular polymorphism in water.
• To couple molecular design with external stimuli for tunable self-assembly.
• To investigate temperature-responsive polymorphic transitions.

Main Methods:

• Design and synthesis of an unsymmetrical oligo(phenyleneethynylene) derivative with specific functional groups (pyridine, amide, chiral side chains).
• Investigation of self-assembly behavior in water across different temperature regimes.
• Analysis of polymorphic transitions using stimuli such as temperature, co-solvents, and metal salts.

Main Results:

• The designed molecule self-assembles into three distinct chiral supramolecular polymorphs (short cylinders, double helical fibers, planar aggregates) at different temperatures.
• Polymorphic transitions are linked to temperature-dependent conformation and dehydration of glycol chains.
• A transient double helical fiber polymorph can be stabilized at room temperature using chemical stimuli.

Conclusions:

• LCST-coupled chirality is an effective strategy for regulating thermoresponsive supramolecular polymorphism.
• The findings offer pathways for designing adaptive materials with controlled self-assembly.
• This work advances the understanding of synthetic chiral supramolecular systems.