From Molecular to Nanostructured Iron Complexes of Amphiphilic Chelators Based on 8-Hydroxyquinoline Subunits – Evidence of Self-Assembled Edifices Mimicking Siderophores from Marine Bacteria

Authors

  • Jérémy Brandel,

    1. Département de Chimie Moléculaire UMR-5250, ICMG FR-2607 CNRS, Université Joseph Fourier, B. P. 53X, 38041 Grenoble Cedex 9, France, Fax: +33-4-76514836
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  • Stéphane Torelli,

    1. Département de Chimie Moléculaire UMR-5250, ICMG FR-2607 CNRS, Université Joseph Fourier, B. P. 53X, 38041 Grenoble Cedex 9, France, Fax: +33-4-76514836
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  • Gisèle Gellon,

    1. Département de Chimie Moléculaire UMR-5250, ICMG FR-2607 CNRS, Université Joseph Fourier, B. P. 53X, 38041 Grenoble Cedex 9, France, Fax: +33-4-76514836
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  • Guy Serratrice,

    1. Département de Chimie Moléculaire UMR-5250, ICMG FR-2607 CNRS, Université Joseph Fourier, B. P. 53X, 38041 Grenoble Cedex 9, France, Fax: +33-4-76514836
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  • Jean-Luc Putaux,

    1. Centre de Recherches sur les Macromolécules Végétales (CERMAV) CNRS, ICMG FR-2607, affiliated with Université Joseph Fourier B. P. 53X, 38041 Grenoble Cedex 9, France
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  • Jean-Louis Pierre

    1. Département de Chimie Moléculaire UMR-5250, ICMG FR-2607 CNRS, Université Joseph Fourier, B. P. 53X, 38041 Grenoble Cedex 9, France, Fax: +33-4-76514836
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Abstract

Amphiphilic iron chelators based on the 8-hydroxyquinoline moiety were synthesized in order to study their potential trend to aggregate into more complex structures. The QS10 and QS4 ligands only differ by the length of the lipophilic alkyl chain (C10 and C4, respectively) tethered to the chelating subunit. Physicochemical investigations in aqueous solution were performed to determine the global stability constants of the iron complexes. At physiological pH, the [Fe(QS10)3]3– predominant species undergoes time-dependent reorganization, as evidenced by cryogenic transmission electron microscopy: after a few hours of equilibration, iron-rich micelles arranged in large clustered structures were observed, whereas after several days complexes were assembled into nanospheres with typical diameters of 100 to 200 nm. This pattern is different from the previous reported amphiphilic catechol derivative and highlights the importance of the nature of the chelating subunit and the residual charge on the type of aggregates formed. These results are relevant to mimic the properties of siderophores from marine bacteria. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)

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