Syntheses, Characterization, and Electrochemical Anion Recognition Investigation of New N‐5‐Ferrocenylisophthalic Amino Acid Methyl Esters

Abstract

AbstractThe N‐5‐ferrocenylisophthalic amino acid methyl esters derivatives 4a–f were prepared by direct condensation of 5‐ferrocenylisophthalic dichloride to the corresponding amino acid methyl esters. The compounds were fully characterized by a range of NMR spectroscopic techniques, mass spectrometry (ESI‐MS) and cyclovoltammetry (CV). The cyclovoltammetric behavior of 4a–f showed one pair of well‐defined and stable redox waves in potential range of 0.0–0.9 V at the GC electrode, which were attributed to the Fc/Fc+ redox process. Electrochemical investigations of 4a–f demonstrated that addition of H2PO4– resulted in large shifts of the respective Fc/Fc+ couple to more negative potentials (ca. 39–68 mV), which suggests that compounds 4a–f have good abilities in recognizing H2PO4–. Moreover, 1H NMR spectroscopic anion titration studies of 4c and 4e strongly suggest the contributions of the amide and Ar–H protons as the important hydrogen donors in anion binding.