INOR 338 |
| Polyamine compounds are ambivalent ligands able to coordinate metal ions or anions depending on the pH of the medium. When the pH is low enough the positively charged ammonium groups can interact with oppositely charged species through electrostatic interactions. At sufficiently high pH values, polyamines interact with metal ions through the electron pairs of their amino groups forming coordinative bonds. These coordination modes can be modulated by the presence of aromatic fragments within the molecule. For instance, with respect to anion coordination, aromatic moieties provide hydrophobic environments in which electrostatic interactions are reinforced. If the anions have also aromatic components they can give rise to stacking interactions. With respect to metal ions, the aromatic fragments can serve as spacers organizing the coordination sites of the molecule. Aromatic components can yield pi-cation interactions and, if they contain heteroatoms, can contribute to the binding through coordinative bonds. Additionally, appropriate aromatic fragments can aid in the recognition of metal ions and anions through the appearance or modification of a physical signal such as the fluorescence emission. Some recent results concerning polyamine receptors of either open-chain, tripodal or cyclic nature will be presented. Attention will be paid to the metal ion and anion coordination behaviour of these compounds and the possibility they have to act as chemosensors. As a final point the incorporation of the polyamines in different solid supports will be discussed. |
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Anion Coordination Chemistry
8:00 AM-12:00 PM, Monday, August 20, 2007 BCEC -- 205C, Oral
Division of Inorganic Chemistry |