Chelating Rotaxane Ligands as Fluorescent Sensors for Metal Ions

Mathieu Denis,Jessica Pancholi,Stephen M. Goldup,Kajally Jobe,Michael Watkinson

doi:10.1002/ange.201712931

Mathieu Denis, Jessica Pancholi + Show 3 more

Open Access

https://doi.org/10.1002/ange.201712931

Copy DOI

Abstract

AbstractAlthough metal‐ion‐binding interlocked molecules have been under intense investigation for over three decades, their application as scaffolds for the development of sensors for metal ions remains underexplored. In this work, we demonstrate the potential of simple rotaxanes as metal‐ion‐responsive ligand scaffolds through the development of a proof‐of‐concept selective sensor for Zn2+.

Highlights

Small molecule fluorescent probes are powerful tools for visualizing metal ions in living systems due to their rapid response time and potential for non-invasive, high resolution and quantitative imaging.[1]
Such small molecule probes are generally composed of a multi-dentate chelating ligand linked to a fluorophore whose output is modulated by the metal binding event
Interlocked molecules,[7] those synthesized using metal-mediated approaches,[8] often possess a well-defined binding pocket containing multiple donor atoms for metal ions.[9]. Such multi-dentate “mechanically chelating” ligands[10] seem ideal for the development of metal-selective ligands and related metal ion sensors by exploiting the size and shape of the three dimensional cavity formed by the mechanical bond

Summary

Introduction

Small molecule fluorescent probes are powerful tools for visualizing metal ions in living systems due to their rapid response time and potential for non-invasive, high resolution and quantitative imaging.[1]. Examination of the selectivity of this response revealed a complete lack of discrimination between Zn2+ and selected divalent metal cations; addition of M(ClO4)2 (M = Mn2+, Fe2+, Co2+, Ni2+, Cu2+, Cd2+, Hg2+) to a solution of 4 led to quenching of the emission to a greater or lesser extent than that observed with Zn2+ (Figure 1b).[23] 4 cannot be classed as a metal ion sensor as, it responds to metal ion binding, it cannot discriminate between competing analytes.

Results

Conclusion