Transition-metal saccharide chemistry: synthesis, spectroscopy, electrochemistry and magnetic susceptibility studies of iron(III) complexes of mono- and disaccharides

Low molecular weight, soluble and characterizable saccharide complexes of iron(III) were synthesised from MeOH using stoichiometric quantities of saccharides and sodium metal. Monosaccharides such as d-glucose, l-sorbose, d-fructose, d-mannose and d-galactose, and disaccharides such as lactose, maltose and sucrose were used for complexation. The final iron(III)-saccharide complexes were isolated, purified and characterised by various analytical, spectroscopic methods including Mossbauer, magnetic susceptibility and electrochemical methods. While half of these complexes were found to be mononuclear, the rest exhibited characteristics close to hydroxo-bridged dinuclear species. The inherent stability and hydrolytically robust nature of these complexes over a wide range of pH was demonstrated. The reductive release of iron from these complexes was shown to be better than that of the iron-dextran complex reported in the literature. Based on their demonstrated properties these may be considered as potentially important in the oral nutritional supplementation of iron.