Chirality Driven Twisting as a Driving Force of Primitive Folding in Binary Mixtures

Area of Science:

• Supramolecular Chemistry
• Materials Science
• Biophysics

Background:

• N-trifluoroacetylated α-aminoalcohols (TFAAAs) exhibit distinct self-assembly behaviors based on chirality.
• Chirally pure TFAAAs form quasi-one-dimensional supramolecular fibers, while racemates form isometric precipitates.
• These fibers induce reversible gelation in solutions.

Purpose of the Study:

• To investigate the formation and properties of supramolecular fibers from TFAAAs.
• To elucidate the mechanism behind gel contraction and the observed rotational dynamics.
• To explore the potential of these systems as molecular motors.

Main Methods:

• Chiral synthesis of N-trifluoroacetylated α-aminoalcohols.
• Solution-based self-assembly studies.
• Microscopic observation (e.g., optical microscopy) of fiber formation and gel dynamics.
• Time-resolved analysis of gel contraction and fiber rotation.

Main Results:

• Chirally pure TFAAAs self-assemble into quasi-one-dimensional supramolecular fibers.
• Fiber formation leads to reversible gelation, with gels initially occupying large volumes and subsequently contracting.
• Microscopic observations revealed significant fiber rotation and coiling, resembling hairpin formation, driving gel contraction.
• The morphology of twisted fibers shows resemblance to protein structures, suggesting analogies in folding mechanisms.
• Fiber rotation converts intermolecular interaction energy into mechanical motion, indicative of molecular motor activity.

Conclusions:

• TFAAAs self-assemble into chiral supramolecular fibers capable of reversible gelation.
• Gel contraction is driven by the rotational dynamics of these fibers, leading to coiling.
• The observed rotational behavior suggests TFAAA gels can function as a simple model for molecular motors.
• The study provides insights into the relationship between molecular structure, self-assembly, and emergent dynamic properties.