Iron(III) complexes of lactobionic acid: equilibrium and structural studies in aqueous solution

Abstract

The equilibrium constants for the protonation of lactobionic acid (4-O-β-D-galactopyranosylgluconic acid) and its co-ordination with Fe^III were studied by potentiometric methods in aqueous solution, at 20.0 °C and I= 0.100 mol dm^–3(NaNO₃). The equilibrium data were processed with the Fortran computer program BEST. Correlations of chelate hydrolysis constants with those of the D-gluconic acid–iron(III) system were carried out. Co-ordination bonding sites and stereochemistry of metal–ligand interactions were inferred from UV and NMR spectroscopy.