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06:35
Construction and Systematical Symmetric Studies of a Series of Supramolecular Clusters with Binary or Ternary Ammonium Triphenylacetates
Published on: February 15, 2016
Exploring the relationship between cocrystal stability and symmetry: is Wallach's rule applicable to multi-component
Tomislav Friscić1, László Fábián, Jonathan C Burley
1Pfizer Institute for Pharmaceutical Materials Science, Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK.
Chemical Communications (Cambridge, England)
|March 28, 2008
Summary
Racemic cocrystals are more stable than chiral ones. This difference in stability is linked to crystal packing or molecular conformation, impacting solid-state properties.
Area of Science:
- Solid-state chemistry
- Crystallography
- Materials science
Background:
- Chiral compounds exist as enantiomers, forming chiral or racemic mixtures.
- Cocrystals are crystalline solids composed of two or more different molecular components.
- Understanding the stability of different solid forms is crucial for pharmaceutical and materials development.
Purpose of the Study:
- To compare the structural and hydration stability of chiral and racemic binary cocrystals.
- To elucidate the factors influencing the observed stability differences between chiral and racemic forms.
Main Methods:
- Crystallization of binary cocrystals in both chiral and racemic forms.
- Structural analysis using X-ray diffraction.
- Assessment of hydration stability under varying humidity conditions.
Main Results:
- Racemic cocrystals exhibited greater hydration stability compared to their chiral counterparts.
- The study identified distinct contributing factors for stability differences: intermolecular crystal packing in one system and intramolecular molecular conformation in another.
- Structural analysis revealed specific packing arrangements correlating with stability.
Conclusions:
- The stability of cocrystals is influenced by both the chirality of the components and their solid-state arrangement.
- Racemic forms can offer enhanced stability, which is advantageous for practical applications.
- Both intermolecular and intramolecular factors play significant roles in determining cocrystal stability, depending on the specific system.
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