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10:37
Spatial Separation of Molecular Conformers and Clusters
Published on: January 9, 2014
Longitudinal positional ordering of n-alkane molecules in urea inclusion compounds
1Institut fur Kristallographie und Angewandte Mineralogie, Ludwig-Maximilians-Universitat Munchen, Germany. thomas.weber@krist.unibe.ch
Acta Crystallographica. Section B, Structural Science
|March 29, 2000
Summary
Urea inclusion compounds show alkane guest molecules ordering longitudinally within host channels. This one-dimensional ordering transitions to long-range order with decreasing temperature, unaffected by other structural changes.
Area of Science:
- Materials Science
- Crystallography
- Supramolecular Chemistry
Background:
- Urea inclusion compounds form host-guest structures with guest molecules confined within channels.
- Understanding the ordering of guest molecules is crucial for controlling material properties.
Purpose of the Study:
- To quantitatively interpret the diffuse layer profiles in diffraction patterns of urea inclusion compounds.
- To investigate the temperature-dependent ordering of alkane guest molecules within urea channels.
Main Methods:
- Analysis of diffuse scattering from diffraction patterns.
- Modeling of longitudinal positional paracrystalline order.
- Investigation of temperature-dependent structural transitions.
Main Results:
- Diffuse layer profiles quantitatively explained by longitudinal paracrystalline order of alkane guests.
- Gradual transition to long-range order observed with decreasing temperature.
- Ordering is independent of lateral correlations and structural phase transformations.
- Mixed alkane systems show superposition of main and satellite layers due to random distribution.
Conclusions:
- Alkane guest ordering in urea channels is primarily a one-dimensional phenomenon.
- Temperature is a key factor driving the transition from paracrystalline to long-range order.
- The host-guest interactions and molecular arrangements are complex and influenced by composition.
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