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Updated: Jun 25, 2026
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Computation of Atmospheric Concentrations of Molecular Clusters from ab initio Thermochemistry
Published on: April 8, 2020
Guest-host hydrogen bonding in structure H clathrate hydrates
Robin Susilo1, Saman Alavi, Igor L Moudrakovski
1Steacie Institute for Molecular Sciences, National Research Council of Canada, Ottawa, Ontario, Canada.
Summary
Tert-butylmethylether (TBME) forms hydrogen bonds in structure H clathrate hydrates, restricting its movement. Neohexane (NH) does not form these bonds, allowing for greater guest mobility within the clathrate cage.
Area of Science:
- Physical Chemistry
- Materials Science
- Chemical Physics
Background:
- Clathrate hydrates are inclusion compounds formed by water cages encapsulating guest molecules.
- Structure H (sH) clathrate hydrates exhibit unique cage structures capable of hosting various guests.
- Understanding guest-host interactions is crucial for applications in gas storage and separation.
Purpose of the Study:
- To investigate the role of guest-host hydrogen bonding in sH clathrate hydrates.
- To contrast the dynamics and structure of tert-butylmethylether (TBME) and neohexane (NH) guests within sH clathrate cages.
- To elucidate how guest molecule structure influences its behavior within the hydrate cage.
Main Methods:
- Conducting molecular dynamics (MD) simulations for TBME and NH sH clathrates.
- Measuring (1)H and (13)C Nuclear Magnetic Resonance (NMR) relaxation times of the guest molecules.
- Analyzing guest structure and dynamics within the sH clathrate cages.
Main Results:
- TBME forms stable, long-lived hydrogen bonds with water molecules in the equatorial region of the sH cage.
- These hydrogen bonds significantly restrict the rattling and rotational motions of TBME within the cage.
- NH, lacking an ether oxygen, does not form hydrogen bonds and exhibits less restricted guest dynamics.
- Despite being isoelectronic, the presence of the oxygen atom in TBME dictates distinct guest-host interactions.
Conclusions:
- Guest-host hydrogen bonding is a key factor governing guest dynamics in sH clathrate hydrates.
- The chemical nature of the guest molecule, specifically the presence of hydrogen bond donors/acceptors, profoundly impacts its confinement behavior.
- This study provides insights into the molecular mechanisms controlling guest mobility in clathrate systems, relevant for materials design.
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