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10:39
Heterogeneous Removal of Water-Soluble Ruthenium Olefin Metathesis Catalyst from Aqueous Media Via Host-Guest Interaction
Published on: August 23, 2018
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Complexation thermodynamics of modified cyclodextrins: extended cavities and distorted structures
Christian Schönbeck1, Peter Westh, René Holm
1NSM, Research Unit for Functional Biomaterials, Roskilde University , Universitetsvej 1, DK-4000 Roskilde, Denmark.
The Journal of Physical Chemistry. B
|August 6, 2014
Summary
Methylated cyclodextrins form inclusion complexes with bile salts. Substituent effects on thermodynamics are explained by dehydration and structural changes, revealing insights into enthalpy-entropy compensation.
Area of Science:
- Supramolecular Chemistry
- Physical Chemistry
Background:
- Modified cyclodextrins are widely studied for their complexation abilities.
- Understanding the thermodynamics of these interactions is crucial for applications.
Purpose of the Study:
- To rationalize the complexation thermodynamics of modified cyclodextrins.
- To investigate the role of methylation on cyclodextrin-bile salt interactions.
Main Methods:
- Calorimetric titrations at various temperatures.
- Molecular dynamics simulations.
- Analysis of enthalpies, entropies, and heat capacities of complexation.
Main Results:
- Methylation induced significant changes in enthalpy and entropy, but smaller changes in Gibbs free energy due to compensation.
- A nonmonotonic trend was observed for thermodynamic parameters with increasing methylation degree.
- Dehydration and structural distortion were identified as key factors influencing complexation thermodynamics.
Conclusions:
- The observed thermodynamic variations are largely explained by changes in dehydration and structural effects.
- Enthalpy-entropy compensation is significantly influenced by hydration variations.
- Findings are applicable to various modified cyclodextrins and highlight general principles in host-guest chemistry.
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