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The synthesis of two new iron chelators built on the tris-L-serine trilactone scaffold of enterobactin and bearing a 8-hydroxyquinoline (oxinobactin) or 8-hydroxyquinoline-5-sulfonate (sulfoxinobactin) unit has been described. The X-ray structure of the ferric oxinobactin has been determined, exhibiting a slightly distorted octahedral environment for Fe(Ⅲ) and a Δ configuration. The Fe(Ⅲ) chelating properties have been examined by Potentiometrie and spectrophotometric titrations in methanol--water 80/20% w/w solvent for oxinobactin and in water for sulfoxinobactin. They reveal the extraordinarily completing ability (pFeⅢ values) of oxinobactin over the p[H] range 2--9, the pFe value at p[H] 7.4 being 32.8. This was supported by spectrophotometric competition showing that oxinobactin removes Fe (Ⅲ) from ferric enterobactin at p[H] 7.4. In contrast, the Fe (III) affinity of sulfoxinobactin was largely lower as compared to oxinobactin but similar to that of the ligand O-TRENSOX having a TREN backbone. These results are discussed in relation to the predisposition by the trilactone scaffold of the chelating units. Some comparisons are also made with other quinoline-based ligands and hydroxypyridinonate ligand (hopobactin). [ABSTRACT FROM AUTHOR]