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Updated: Jun 28, 2026
10:37
Spatial Separation of Molecular Conformers and Clusters
Published on: January 9, 2014
Size-restricted proton transfer within toluene-methanol cluster ions
Chi-Tung Chiang1, Kevin S Shores, Marek Freindorf
1Department of Chemistry, University at Buffalo, State University of New York at Buffalo, Buffalo, New York 14260-3000, USA.
The Journal of Physical Chemistry. A
|October 28, 2008
Summary
Toluene and methanol cluster ion reactivity was studied. Proton transfer occurs for small methanol clusters (n=2-4), with larger clusters needing to fragment first.
Area of Science:
- Physical Chemistry
- Chemical Physics
- Molecular Interactions
Background:
- Understanding ion-molecule reactions is crucial in various chemical processes.
- Investigating cluster ions provides insights into solvation and reaction mechanisms.
- Toluene and methanol interactions are relevant in atmospheric and industrial chemistry.
Purpose of the Study:
- To elucidate the chemical reactivity and proton transfer dynamics of toluene-methanol cluster ions.
- To determine the influence of methanol cluster size on intracluster proton transfer.
- To explore the interplay between cluster structure, proton affinity, and reaction energetics.
Main Methods:
- Tandem quadrupole mass spectrometry was employed to study cluster ion fragmentation.
- Collision-Induced Dissociation (CID) experiments were performed on [(C6H5CH3)(CH3OH)n](+) ions (n=1-7).
- Computational calculations were utilized to analyze reaction pathways and energy barriers.
Main Results:
- Intracluster proton transfer from toluene to methanol occurs for n=2-4 methanol units.
- Larger clusters (n=5-7) require sequential methanol monomer loss to facilitate proton transfer.
- The (CH3OH)3H(+) ion is the preferred product for n=3 and n=4, indicating size-specific reactivity.
- Cluster structure and methanol subcluster proton affinity govern the proton transfer reaction.
Conclusions:
- The size of the methanol subcluster significantly dictates the feasibility of intracluster proton transfer.
- Cooperative effects in smaller methanol subclusters (n=3) lower the energy barrier for proton transfer.
- Ring structures in larger methanol subclusters (n>=4) stabilize the cluster, hindering direct proton transfer.
- The observed size-restricted reaction is driven by both proton affinity and product stability.
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