Inorg. Chem. 50, 4212-4220 (2011)

DOI: 10.1021/ic102314r

Unprecedented 1,3-Diaza[3]ferrocenophane Scaffold as Molecular Probe for Anions

The guanidine unit in the guise of 2-aminoimidazole in the new structural motif 2-arylamino-1,3-diaza[3]ferrocenophane 4 acts as a binding site for anions. The electrochemical behavior of this compound has been studied by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) and was found to exhibit a quasi reversible oxidation peak, associated to the Fe(II)/Fe(III) redox couple (Ep = 440 mV), and a non-reversible oxidation wave (Ep = 817 mV), probably associated to the oxidation of the C═N unit present in the guanidine bridge. Recognition of AcO, PhCO2, F, Cl, and Br anions by the free receptor and the less basic anions Br, Cl, and NO3 by its monoprotonated form takes place by unusual redox-ratiometric measurements and spectroscopic (1H NMR and UV−vis) changes.