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CH-π Interactions Elucidated at the Single-Molecule Level
Qianyuan Ren1,2, Wenying Hao2,3, Lixia Wang4
1College of Food and Bioengineering, Xihua University, Chengdu 610039, China.
Journal of the American Chemical Society
|August 29, 2025
Summary
This study quantifies CH-π interactions using a protein nanopore system. Deuterium forms weaker CD-π interactions than protic CH-π interactions, resolving a long-standing scientific debate.
Area of Science:
- Biophysics
- Chemical Physics
- Molecular Interactions
Background:
- CH-π interactions are crucial molecular forces in biological and chemical systems.
- Experimentally measuring weak CH-π interactions is challenging due to stronger concurrent noncovalent forces.
Purpose of the Study:
- To accurately compare the strength of CH-π interactions between phenylalanine derivatives and aliphatic amino acids.
- To resolve the debate on the deuterium isotope effect in CH-π interactions.
Main Methods:
- Utilized a refined protein nanopore system for molecular exchange processes.
- Quantitatively compared binding strengths to determine interaction forces.
Main Results:
- CH-π interactions are dominated by dispersive attraction.
- More acidic C-H bonds lead to stronger CH-π interactions.
- Confirmed that deuterium forms weaker CD-π interactions compared to CH-π interactions.
Conclusions:
- The study provides a robust method for measuring weak CH-π interactions.
- Resolved the deuterium isotope effect, showing CD-π interactions are weaker than CH-π interactions.
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