Complexation of Ln(III) and Ca(II) Cations with 3,4-Dicarboxyinulin and Model Compounds: Methyl 3,4-Dicarboxy-alpha-D-fructofuranoside and 3,4-Dicarboxynystose, As Studied by Multinuclear Magnetic Resonance Spectroscopy and Potentiometry.
Complexes of Ln(III) and Ca(II) cations with 3,4-dicarboxyinulin (DCI) and model compounds, methyl 3,4-dicarboxy-alpha-D-fructofuranoside (DCF) and 3,4-dicarboxynystose (DCN) were studied using multinuclear magnetic resonance spectroscopy and potentiometric methods. Complexes of the model compounds with Ln(III) ions provided a feasible way in which to study complexation phenomena of the dicarboxyinulin/Ca(II) system using NMR techniques. Information on complex geometry was derived from the effect of Ln(III) ions on chemical shifts and longitudinal relaxation rates. Metal-ligand stoichiometries of 1:2 and 1:1, in which the ligand coordination was tridentate as well as tetradentate, were found. Potentiometric measurements carried out with Ca(II) yielded information on the stoichiometry as well as the cooperativity of metal ion binding by the ligands.
Johnson
Louise
L
Laboratory of Organic Chemistry and Catalysis, Delft University of Technology, Julianalaan 136, 2628 BL Delft, The Netherlands, and TNO Biotechnology and Chemistry Institute, P.O. Box 360, 3700 AJ Zeist, The Netherlands.
Verraest
Dorine L.
DL
Besemer
Arie C.
AC
van Bekkum
Herman
H
Peters
Joop A.
JA