Partner und Internationale Organisationen
(Englisch)
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A, B, CH, CZ, D, DK, E, F, FIN, GR, H, I, IRL, N, NL, P, RO, S, SI
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Abstract
(Englisch)
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The main idea behind this project was the investigation of classes of ligands able to produce both chelates having good contrast agent ability for magnetic resonance imaging (MRI) and luminescent complexes for the labelling of biological materials and for mapping purposes. The project has developed along two lines, one resorting to compounds derived from the cyclen framework and the other one to macrocyclic compounds. In the first part, four differently substituted cyclen-based macrocycles have been synthesized and characterized, as well as their complexes with trivalent lanthanide ions. The latter were characterized by X-ray crystallography (5 structures). A detailed photophysical study has clearly demonstrated that not only the distance from the organic chromophore to the metal ion is crucial in attaining a sizable energy transfer but, also, the respective orientation of the donor and the acceptor. These results, described in one PhD thesis, shed a new light on the design of lanthanide-containing luminescent edifices. The second part of the project ha been initiated thanks to a new collaboration with a Spanish group. We have tested the capacity of Schiff base macrocycles and macrobicycles for the encapsulation of Ln(III) ions and for enhancing their photophysical properties. If the tested ligands did not prove very good in sensitizing the luminescence of the Eu(III) ion, we demonstrated that one ligand is a good candidates to transfer energy on the Yb(III) ion which, in turn, emits in the near infrared, a spectral range drawing much attention presently in view of potential applications for low-energy luminescent probes testing biological materials. The results obtained have been described in three published paper (a fourth one has been submitted) and presented at six meetings under the form of three invited lectures and three posters. Links have been established with two research groups, one in Spain and the other one in Portugal, while collaboration with an in-house group has been deepened. One graduate student has completed his PhD thesis in Lausanne during the project.
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