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Trapping Alkali Halide Cluster Ions Inside the Cucurbit[7]uril Cavity
Jiyeon Lee1, Seongjae Jang1, Minsu Kim1
1Department of Chemistry, Pohang University of Science and Technology, Pohang 37673, Gyeongsangbuk-do, Republic of Korea.
The Journal of Physical Chemistry Letters
|October 7, 2022
Summary
Cucurbit[n]urils (CB[n]) capture alkali halide clusters during droplet evaporation. Smaller clusters are trapped inside the CB[7] cavity in the gas phase, forming inclusion complexes.
Area of Science:
- Supramolecular Chemistry
- Analytical Chemistry
- Physical Chemistry
Background:
- Cucurbit[n]urils (CB[n]) are macrocyclic hosts known for encapsulating guest molecules.
- Alkali halide clusters are relevant in various chemical and physical processes.
- Understanding host-guest interactions in the gas phase is crucial for molecular recognition.
Purpose of the Study:
- To investigate the gas-phase behavior of cucurbit[n]uril (CB[n]) interacting with alkali halide clusters.
- To determine the size limitations for alkali halide cluster encapsulation within the CB[7] cavity.
- To explore the mechanism of inclusion complex formation during droplet evaporation.
Main Methods:
- Ion mobility spectrometry-mass spectrometry (IMS-MS) was employed to study CB[7] complexes.
- Collision cross-section (CCS) values were measured for alkali chloride cluster-CB[7] complexes.
- Electrospray ionization was used to generate gas-phase ions.
Main Results:
- CB[7] was observed to capture alkali chloride clusters of varying sizes during droplet evaporation.
- A critical size limit was identified, below which clusters were successfully trapped within the CB[7] cavity.
- Gas-phase trapping occurred despite unfavorable solution-phase conditions for alkali halide cluster formation.
Conclusions:
- Gas-phase trapping of alkali halide clusters by CB[7] is size-dependent.
- Rapid solvent evaporation during electrospray ionization facilitates the formation of inclusion complexes.
- This study reveals a unique gas-phase encapsulation mechanism for cucurbit[n]urils with alkali halide clusters.
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