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From Molecules to Materials: Engineering New Ionic Liquid Crystals Through Halogen Bonding
Published on: March 24, 2018
Thermodynamics of halogen bonding in solution: substituent, structural, and solvent effects
Mohammed G Sarwar1, Bojan Dragisic, Lee J Salsberg
1Department of Chemistry, Lash Miller Chemical Laboratories, University of Toronto, Toronto, Ontario M5S 3H6, Canada.
Journal of the American Chemical Society
|January 19, 2010
Summary
This study quantifies halogen bonding thermodynamics in solution using NMR titrations. Electrostatic models show limitations, highlighting solvent effects and differences from hydrogen bonding.
Area of Science:
- Physical Chemistry
- Organic Chemistry
- Supramolecular Chemistry
Background:
- Halogen bonding is a significant non-covalent interaction.
- Understanding its thermodynamics in solution is crucial for chemical applications.
- Existing models often rely on simplified electrostatic descriptions.
Purpose of the Study:
- To conduct a detailed thermodynamic study of halogen bonding in organic solution.
- To investigate the influence of substituents on halogen bond donor ability.
- To compare the limitations of electrostatic models with computational and solvent effect data.
Main Methods:
- Utilized (19)F NMR titrations to determine association constants.
- Employed substituted iodoperfluoroarenes as halogen bond donors.
- Analyzed linear free energy relationships using substituent constants and electrostatic potentials.
- Evaluated computationally derived binding energies and solvent effects.
Main Results:
- Quantified association constants for various Lewis base-iodine interactions.
- Established linear free energy relationships for halogen bond donors.
- Demonstrated limitations of purely electrostatic models for comprehensive halogen bonding data.
- Identified significant solvent effects and differences compared to hydrogen bonding.
Conclusions:
- Halogen bonding thermodynamics in solution can be accurately determined using NMR titrations.
- Electrostatic models are useful but insufficient for complex halogen bonding scenarios.
- Solvent effects play a critical role, distinguishing halogen bonding from hydrogen bonding.
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