Ferrocenoyl-amino acids: redox response towards di- and trivalent metal ions

The interaction of six ferrocene-amino acid conjugates (Fc-CO-Gly-OH (2a), Fc-CO-Asp-OH (3a), Fc-CO-Glu-OH (4a), 1,1'-Fc(CO-Gly-OH) (2b), 1,1'-Fc(CO-Asp-OH) (3b), and 1,1'-Fc(CO-Glu-OH) (4b)) with Mg2+ Ca2+, Zn2+, La3+, and Tb3+ was investigated in aqueous solutions using cyclic voltammetry (CV) and differential pulse voltammetry (DPV). Addition of metal ions to solutions caused, in some cases, large changes in the half-wave potential, E-1/2. Our electrochemical results show that the Gly systems, 2a and 2b, show a preference for binding Mg2+, whereas the Asp and Glu conjugates prefer binding Ln(3+). (c) 2004 Elsevier B.V. All rights reserved.