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

• Published in: Inorganic chemistry Vol. 50; no. 9; pp. 4212 - 4220
• Main Authors: Sola, Antonia, Orenes, Raúl A, García, María Ángeles, Claramunt, Rosa M, Alkorta, Ibon, Elguero, José, Tárraga, Alberto, Molina, Pedro
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 02.05.2011
• Subjects: Anions - chemistry; Colorimetry; Ferrous Compounds - chemistry; Isomerism; Models, Molecular; Molecular Conformation; Molecular Probes - chemistry; Oxidation-Reduction; Spectrum Analysis
• ISSN: 0020-1669; 1520-510X
• DOI: 10.1021/ic102314r

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.