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Crystal structure of beta-cyclodextrin-dimethylsulfoxide inclusion complex
Thammarat Aree1, Narongsak Chaichit
1Department of Chemistry, Faculty of Science, Chulalongkorn University, Phyathai Road, Pathumwan, Bangkok 10330, Thailand. mam@atc.atccu.chula.ac.th
Carbohydrate Research
|December 21, 2002
Summary
This study details the crystal structure of beta-cyclodextrin (beta-CD) complexed with DMSO and water. The findings reveal specific hydrogen bonding interactions and molecular arrangements critical for crystal stability.
Area of Science:
- Supramolecular Chemistry
- Crystallography
- Materials Science
Background:
- Beta-cyclodextrin (beta-CD) is a cyclic oligosaccharide with a hydrophobic cavity, widely used in drug delivery and separation science.
- Understanding the precise crystalline structure of beta-CD complexes is crucial for optimizing its applications.
- Solvent inclusion in cyclodextrin crystals significantly influences their structural properties and stability.
Purpose of the Study:
- To elucidate the detailed crystal structure of beta-cyclodextrin co-crystallized with dimethyl sulfoxide (DMSO) and water.
- To characterize the conformation of the beta-CD macrocycle and the precise location and interactions of guest molecules within the crystal lattice.
- To investigate the role of water molecules as hydrogen bonding mediators in stabilizing the crystal structure.
Main Methods:
- Single-crystal X-ray diffraction analysis was employed to determine the crystal structure.
- Anisotropic refinement of atomic parameters was performed using 9,127 diffraction data points.
- Computational modeling and analysis of hydrogen bonding networks were utilized to understand structural stability.
Main Results:
- Beta-cyclodextrin (beta-CD) crystallizes as beta-CD.0.5DMSO.7.35H(2)O in the monoclinic space group P2(1).
- The beta-CD macrocycle adopts a 'round' conformation stabilized by intramolecular hydrogen bonds.
- DMSO and water molecules are disordered within the cavity, with specific hydrogen bonding interactions to water and the beta-CD hydroxyl groups, contributing to crystal stability.
Conclusions:
- The crystal structure provides a detailed molecular-level understanding of beta-CD-DMSO-water interactions.
- The extensive hydrogen bonding network, mediated by disordered water molecules, is key to the stability of the observed crystalline form.
- This structural insight is valuable for the rational design of beta-CD based materials and formulations.