The application of siderophores for metal recovery and waste remediation: examination of correlations for prediction of metal affinities

The naturally occurring metal-chelating compounds known as siderophores may be useful in environmental applications, but limited metal specificity data is available for this class of compounds. Correlations that predict ligand–metal affinity vs metal ion charge density and hydrolysis behavior are applied to the case of the siderophore desferrioxamine B (DFB). DFB–metal complex formation constants are better correlated to the first hydrolysis constant of the respective metal cations than to the ratio of charge to metal–ligand interatomic separation. Test cases of Pb II, Sn II and Bi III confirm this conclusion.