Preparation, Structural Characterization, Electrochemistry, and Sensing Properties toward Anions and Cations of Ferrocene-Triazole Derivatives

A number of monosubstituted (3, 4, 6, 8, 9, 11, and 13) and disubstituted (15 and 16) ferrocene-derived triazoles have been prepared, by using the copper-catalyzed click reaction, and fully characterized. The versatility of the click reaction enables the decoration of the ferrocene-triazole core, with additional substituents displaying different opto-electrochemical properties. The most salient features derived from the sensing studies are that receptors 3, 6, 15, and 16 undergo unprecedented cathodic shifts of the oxidation peak of the ferrocene/ferrocenium redox couple in the presence of F-, AcO-, H2PO4-, and HP2O73- anions, whereas receptors 11 and 16 behave as dual redox and optically selective molecular sensors for Hg2+ cations. The isolated [6(3)center dot Ni2+] complex has been characterized by X-ray analysis.