Département de chimie moléculaire

The synthesis of two new Fe chelators built on the tris-L-serine trilactone scaffold of enterobactin and bearing a 8-hydroxyquinoline (oxinobactin) or 8-hydroxyquinoline-5-sulfonate (sulfoxinobactin) unit was described. The x-ray structure of the ferric oxinobactin was detd., exhibiting a slightly distorted octahedral environment for Fe(III) and a $Δ$ configuration. The Fe(III) chelating properties were examd. by potentiometric and spectrophotometric titrns. in MeOH-H2O 80/20{%} wt./wt. solvent for oxinobactin and in H2O for sulfoxinobactin. They reveal the extraordinary complexing 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). [on SciFinder(R)]