D. Research Applications:

2. Recogniton of a Chiral Complex in the Mediated Transport of Iron by E. Coli
Research by Kenneth N. Raymond and his research associates at the University of California, Berkeley

Professor Ken Raymond and his research group at the University of California, Berkeley examine a wide variety of questions in inorganic chemistry and he is well known for his work in the development of chelating agents that have been designed to selectively bind a given metal. Research in his laboratory spans from the study of naturally occuriing iron sequestering agents, to the design of molecules to sequester lanthanides and actinides from biological organisms or the environment. His group is also well known for the examination of the supramolecular structure that ligands impose on metal clusters.
One example of his work that addresses the chiral nature of iron transport in some micro-organisms is illustrated here:

 The Proposed Structure of [&Delta -Iron(III)enterobactin]3-shown on your left is based on the crystal structure of
[&Delta-Vanadium(IV)enterobactin]2- published in the literature
Reference: (CCDC Structure JOSLOS01) Karpishin, T. B., Dewey, T. M., Raymond K.N.;
J. Am. Chem. Soc. 1993, p. 1842, DOI
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Molecular Features:
  1. Three Catechol Binding Subunits () are covalently linked by
  2. A tri-L-serine backbone
    • Note that this is a "depsi-peptide": The L-serine units are linked by ester linkages NOT amide linkages:
  3. The Absolute Configuration around the metal center may be assigned as &Delta using the methods described in Section C and facilitated with the following tools:

  4. Research by the Raymond group and others shows:
    • Biological activity is Stereoselective (for the &Delta isomer)
    • And Regioselective for this region () of the molecule.
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