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Bis-butoxyphenyl dipyridine cation with high affinity for PF6−: Enhancement of solid fluorescence and inhibits Escherichia coli and Staphylococcus aureus activity through anion-π+ interactions

Chen, Ling; Zhou, Xu; Shen, Lingyi; Peng, Senlin; Yuan, Jing Li; Xu, Hong; Wang, Zhi Yong; Redshaw, Carl; Zhang, Qi Long

Authors

Ling Chen

Xu Zhou

Lingyi Shen

Senlin Peng

Jing Li Yuan

Hong Xu

Zhi Yong Wang

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Professor Carl Redshaw C.Redshaw@hull.ac.uk
Professor of Inorganic Materials Chemistry and REF Lead for Chemistry

Qi Long Zhang



Abstract

The contamination of anions and the overuse of antibiotics pose significant hazards to human health. Excess anions can cause serious damage to organisms and the natural environment, while the misuse of antibiotics has led to the emergence of multi-drug resistant bacteria. Therefore, it is important to develop multifunctional fluorescent sensing devices that integrate the rapid and sensitive detection of specific anions and that exhibit excellent antimicrobial activity against multi-resistant bacteria. This study describes the synthesis of three water-soluble cationic fluorescent molecules, DPPT-R (R = 5C, 6C, 7C). Their structures were characterized using 1H NMR spectroscopy, HRMS, and single crystal X-ray diffraction. Spectroscopic properties of the probes were recorded using UV–visible absorption and fluorescence spectroscopy. The recognition mode and mechanism of the fluorescent probes towards PF6− were investigated. Under aqueous solution conditions involves the PF6− induced aggregation of the probe via strong electrostatic interactions, leading to fluorescence quenching. Adjusting the alkyl chain length of the probe can enhance the sensitivity for the detection of the target anions. The detection limits are 0.892 μM, 0.786 μM and 0.444 μM for R = 5C, 6C, 7C, respectively. In addition, DPPT-R and DPPT-R@PF6 exhibit good inhibitory activity and fluorescence imaging capability against methicillin-resistant Staphylococcus aureus and multidrug-resistant Escherichia coli. Among them, the side chain of DPPT-R@PF6 with an almost 90° bend may be more advantageous for membrane insertion, thus enhancing its antimicrobial activity. In particular, after DPPT-R and PF6− form the DPPT-R@PF6 complex, the complex enhances its solid-state fluorescence, intensity of bacterial fluorescence imaging, and antibacterial activity through anion-π+ interactions. Therefore, this study can provide a new strategy and theoretical basis for the design and application of multifunctional fluorescent sensing materials and antibacterial molecules based on electrostatic interactions and anion-π+ interactions.

Citation

Chen, L., Zhou, X., Shen, L., Peng, S., Yuan, J. L., Xu, H., Wang, Z. Y., Redshaw, C., & Zhang, Q. L. (2024). Bis-butoxyphenyl dipyridine cation with high affinity for PF6−: Enhancement of solid fluorescence and inhibits Escherichia coli and Staphylococcus aureus activity through anion-π+ interactions. Journal of molecular structure, 1315, Article 138783. https://doi.org/10.1016/j.molstruc.2024.138783

Journal Article Type Article
Acceptance Date May 27, 2024
Online Publication Date May 29, 2024
Publication Date Nov 5, 2024
Deposit Date Jun 15, 2024
Publicly Available Date May 30, 2025
Journal Journal of Molecular Structure
Print ISSN 0022-2860
Publisher Elsevier
Peer Reviewed Peer Reviewed
Volume 1315
Article Number 138783
DOI https://doi.org/10.1016/j.molstruc.2024.138783
Public URL https://hull-repository.worktribe.com/output/4710451