Issue 37, 2010

Ferrocene-based multichannel molecular chemosensors with high selectivity and sensitivity for Pb(ii) and Hg(ii) metal cations

Abstract

The synthesis, electrochemical, optical and cation-sensing properties of ferrocene-imidazoquinoxaline dyads 6, are presented. Dyad 6a behaves as a highly selective redox, chromogenic and fluorescent chemosensor molecule for Pb2+ cations in CH3CN solutions; the oxidation redox peak is anodically shifted (ΔE1/2 = 110 mV); in the absorption spectrum a new low-energy band appeared at λ = 463 nm, and the emission band is red-shifted (Δλ = 31 nm) along with an important chelation-enhanced fluorescence factor (CHEF = 276), upon complexation with this metal cation. The dyad 6b, bearing two additional pyridine rings as substituents, has shown its ability for sensing Hg2+ cations through three different channels: the oxidation peak is anodically higher shifted (ΔE1/2 = 300 mV), a new low-energy band appears in the absorption spectrum at λ = 483 nm, and the emission band was also red-shifted (Δλ = 28 nm) and underwent an important chelation-enhanced fluorescent factor (CHEF = 227). The changes in their absorption spectra are accompanied by color changes from yellow to orange which allow their potential use for the “naked eye” detection of these metal cations. Linear sweep voltammetry revealed that Cu2+ cations induced oxidation of the ferrocene unit in both dyads, which is accompanied by an important increase of the emission band.

Graphical abstract: Ferrocene-based multichannel molecular chemosensors with high selectivity and sensitivity for Pb(ii) and Hg(ii) metal cations

Supplementary files

Article information

Article type
Paper
Submitted
10 May 2010
Accepted
30 Jun 2010
First published
11 Aug 2010

Dalton Trans., 2010,39, 8637-8645

Ferrocene-based multichannel molecular chemosensors with high selectivity and sensitivity for Pb(II) and Hg(II) metal cations

M. Alfonso, A. Tárraga and P. Molina, Dalton Trans., 2010, 39, 8637 DOI: 10.1039/C0DT00450B

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