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Construction and Systematical Symmetric Studies of a Series of Supramolecular Clusters with Binary or Ternary Ammonium Triphenylacetates
Published on: February 15, 2016
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Supramolecular chirality induced by a weak thermal force.
Placido Mineo1, Valentina Villari, Emilio Scamporrino
1Dipartimento di Scienze Chimiche and I.N.S.T.M. UdR of Catania, University of Catania, Viale Andrea Doria 6, I-95125 Catania, Italy. gmineo@unict.it.
Soft Matter
|March 22, 2014
Summary
Small temperature gradients unexpectedly induce chirality in achiral porphyrin aggregates. This thermal force drives aggregate motion, and optical activity can be controlled by minimizing this force.
Area of Science:
- Supramolecular Chemistry
- Physical Chemistry
- Materials Science
Background:
- Achiral molecules can form chiral aggregates under specific conditions.
- Temperature gradients can induce asymmetry and influence molecular self-assembly.
- Porphyrin systems are widely studied for their optical and electronic properties.
Purpose of the Study:
- To elucidate the origin of unexpected chirality in aggregated achiral porphyrin systems.
- To investigate the role of temperature gradients in inducing asymmetry.
- To demonstrate control over the optical activity of these aggregates.
Main Methods:
- Formation of aggregated structures from an uncharged achiral porphyrin system.
- Application of small, controlled temperature gradients.
- Measurement of thermophoretic motion and induced optical activity.
Main Results:
- Small temperature gradients were identified as the source of asymmetry, leading to chiral aggregate formation.
- The thermal force generated drives the thermophoretic motion of the porphyrin aggregates.
- Induced optical activity was found to be controllable by modulating the thermal force.
Conclusions:
- Chirality in these porphyrin aggregates arises from subtle thermal perturbations, not inherent molecular chirality.
- Thermophoresis, driven by thermal gradients, plays a key role in the self-assembly process.
- Minimizing thermal gradients offers a method to control or eliminate the observed optical activity.
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