Single-Molecule Force Spectroscopy Reveals Cation- π Interactions in Aqueous Media Are Highly Affected by Cation Dehydration
2023; American Physical Society; Volume: 130; Issue: 11 Linguagem: Inglês
10.1103/physrevlett.130.118101
ISSN1092-0145
AutoresWeishuai Di, Kai Xue, Jun Cai, Zhenshu Zhu, Zihan Li, Hui Fu, Hai Lei, Wenbing Hu, Chun Tang, Wei Wang, Yi Cao,
Tópico(s)Lipid Membrane Structure and Behavior
ResumoCation-π interactions underlie many important processes in biology and materials science. However, experimental investigations of cation-π interactions in aqueous media remain challenging. Here, we studied the cation-π binding strength and mechanism by pulling two hydrophobic polymers with distinct cation binding properties, i.e., poly-pentafluorostyrene and polystyrene, in aqueous media using single-molecule force spectroscopy and nuclear magnetic resonance measurement. We found that the interaction strengths linearly depend on the cation concentrations, following the order of Li^{+}<NH_{4}^{+}<Na^{+}<K^{+}. The binding energies are 0.03-0.23 kJ mol^{-1} M^{-1}. This order is distinct from the strength of cation-π interactions in gas phase and may be caused by the different dehydration ability of the cations. Taken together, our method provides a unique perspective to investigate cation-π interactions under physiologically relevant conditions.
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