Competition of ion-pair during the transition from hydrogen bonding to electrostatic interaction on self-assembled monolayer. (20th November 2021)

• Record Type: Journal Article
• Authors: Li, Na; Chen, Jingchao; Huang, Ximing; Guo, Haixia; Li, Xia; Fan, Aihua; Shao, Huibo
• Is Part Of: Electrochimica acta. Volume 397(2021)
• Publication Date: 2021-11-20
• Subjects: Competition -- Ion-pair -- Electrostatic interaction -- Self-assembled monolayer -- Scanning electrochemical microscopy; Electrochemistry -- Periodicals; Electrochemistry, Industrial -- Periodicals; 541.37
• DOI: 10.1016/j.electacta.2021.139310
• Languages: English
• ISSNs: 0013-4686

Abstract

Highlights: The competition of two weak intermolecular interactions for ion-pair and electrostatic interaction was investigated by SECM. The competitive phenomena were suitably characterized by the change of tip electrode current. The competitive strength was enhanced by increasing anion concentration and solution acidity. Probing the competitive mechanisms is conducive to comprehending biological recognition process. Abstract: The competition of intermolecular interactions occurring on the cellular surface plays a vital role in governing biological recognition processes. Herein, the competition between ion-pair and electrostatic interaction on the surface of a reliable artificial membrane, 3-mercaptopropionic acid self-assembled monolayer (3-MPA SAM), was investigated using scanning electrochemical microscopy (secm). The electroactive agent ferrocenemethanol (FcCH2 OH) with one hydroxyl group is adsorbed by terminal carboxyl groups of 3-MPA SAM via hydrogen bonding. Once FcCH2 OH was oxidized into ferroceniummethanol (Fc + CH2 OH) by applying an oxidative potential, the electrostatic interaction between Fc + CH2 OH and the deprotonated carboxyl group of 3-MPA became the dominant intermolecular force in the reaction system accompanied by the breaking of hydrogen bonding. With the addition of perchlorate anion (ClO4 − ), noticeable competition between the ion-pair and electrostatic interaction was observed owing to the spontaneous pairing of Fc + CH2 OH and ClO4 − . The competitive strength of ion-pair could be enhanced by increasing ClO4 − concentration or solution acidity. Compared with the other six anions, ClO4 − has been proved to exhibit more effective competition with the electrostatic interaction, which might attribute to the differences in hydration energy and the pairing capacities with Fc + CH2 OH. This work may contribute to comprehending the biological recognition on the cellular surface and deserve further investigation. Graphical abstract: Image, graphical abstract