A Simple but Effective Dual Redox and Fluorescent Ion Pair Receptor Based on a Ferrocene-Imidazopyrene Dyad

The ferrocene-imidazopyrene dyad, bearing the imidazole ring as the only receptor site, acts as a redox and optical molecular sensor for ion pairs, exhibiting an easily detectable signal change in the redox potential of the ferrocene/ferrocinium redox couple and in the emission spectrum. Perturbation of the emission spectrum follows the order Pb2+ > Hg2+ > Zn2+ for cations and H2PO4- > AcO- for anions.