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Aromatic-aromatic ring interaction revisited with model compounds of Wilcox
1Center for Biofunctional Molecules, Pohang University of Science and Technology, Korea.
Journal of Biomolecular Structure & Dynamics
|December 17, 1997
Summary
Aromatic interactions favor folded shapes at low temperatures. Solvent effects create a free energy cancellation, making these interactions significant for molecular conformation.
Area of Science:
- Chemical Physics
- Molecular Interactions
- Organic Chemistry
Background:
- Aromatic-aromatic nonbonded interactions are crucial in molecular structure.
- Previous studies utilized model compounds to investigate these interactions.
Purpose of the Study:
- To reexamine aromatic-aromatic nonbonded interactions.
- To investigate the influence of temperature on conformational preferences.
Main Methods:
- Utilized model compounds previously studied by Wilcox and collaborators.
- Analyzed conformational populations at temperatures down to 210 K.
Main Results:
- Folded conformers (A) were more populated than unfolded conformers (B) at low temperatures.
- Edge-to-face aromatic-aromatic ring interactions were suggested to be in effect.
- The free energy difference between conformers did not show linear temperature dependence.
- A free energy cancellation effect due to solvent molecules was proposed.
Conclusions:
- Solvent molecules significantly influence the observed free energy differences.
- Despite a small net gain (approx. 0.5 kcal/mol) in organic solvents, aromatic interactions play a key role in conformational preference.