Redox-gated recognition of dihydrogen phosphate using a ferrocene-tethered non-symmetric aryl-triazole pentad

ABSTRACT

Anions play many roles in our environment. Consequently, the development of synthetic receptors capable of targeted anion binding is of ongoing importance. While many such receptors are known, simplified designs and measurement approaches are always beneficial. Herein, we report the synthesis of a non-symmetric aryl-triazole pentad receptor appended with a single ferrocene, its electrochemistry, and the selective binding to dihydrogen phosphate (H₂PO₄^–) anions of its oxidised form over various environmentally prevalent anions (HSO₄^–, Cl^–, NO₃^–). The receptor was constructed using a modular architecture with simple installation of a ferrocene unit using click chemistry. Electrochemical analysis on the receptor revealed that addition of H₂PO₄^– anion led to a shift in the redox peaks of the receptor (FcP) towards more negative potentials, indicating higher anion affinity was achieved after the ferrocene was oxidised to its cationic form (FcP⁺). This work verifies prior studies on the efficacy of cationic charge in simpler receptor design for the creation of functional host-guest systems.

GRAPHICAL ABSTRACT

KEYWORDS:

• Anions
• recognition
• ferrocene
• triazoles

Acknowledgments

We acknowledge support from the NSF (CHE-2305013). J.B.U. was supported by NSF REU grant number CHE-1852182. We acknowledge NMR support from NSF MRI CHE-1920026. The prodigy probe was partially funded by Indiana Clinical and Translational Sciences Institute. In addition, we thank Dr. Li Sun (Pine Research Instrumentation) for his help with the digital CV simulations.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Supplementary material

Supplemental data for this article can be accessed online at https://doi.org/10.1080/10610278.2024.2326525

Additional information

Funding

The work was supported by the National Science Foundation [CHE-1852182]; National Science Foundation [MRI CHE-1920026]; National Science Foundation [CHE-2305013].

Notes on contributors

Nabarupa Bhattacharjee

Nabarupa Bhattacharjee Conceptualization, Synthesis, Investigation, Formal analysis, Writing – original draft and editing.

Akash Nathani

Akash Nathani Electrochemistry, Investigation, Formal analysis, Writing – review & editing.

James B. Unzaga

James B Unzaga Electrochemistry.

Takashi Ito

Takashi Ito Conceptualization, Funding acquisition, Supervision, Digital CV simulations, Project administration, Writing – review & editing.

Amar H. Flood

Amar H. Flood Conceptualization, Funding acquisition, Supervision, Project administration, Writing – review & editing.