Description succincte
(Anglais)
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The project is concerned with the reduction of any multicomponent self-assembly, in particular helicate self-assemblies, to the combination of a minimal set of microscopic parameters. The subsequent modelling of the associated formation constants allows the interpretation and unravelling of the fundamental origins of preorganization and cooperativity, which are responsible for the fine molecular recognition processes leading to the final sophisticated supramolecular edifices. Much efforts are focussed on the synthesis of a family of structurally-related triple-stranded helicates displaying increasing nuclearites (bimetallic to pentametallic), and from which the dependence of the entropic corrections for macrocyclization and of the intermetallic interactions on the intersite separation can be extracted. Since 4f-block ions are used as the basic metallic components of these architectures, optical and magnetic functions can be exploited in programmed heterometallic helicates resulting from this bottom-to-top approach.
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Partenaires et organisations internationales
(Anglais)
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AT, BE, CH, CZ, DE, DK, ES, FI, FR, GR, HR, HU, IL, IT, LT, NL, NO, PL, PT, SE, SI, UK
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Résumé des résultats (Abstract)
(Anglais)
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The completion of the collection of experimental thermodynamic data through the synthesis and characterization of an ultimate series of trinuclear bimetallic d-f-f triple-stranded helicates allowed (i) the non-constrained evaluation of indepedent intramolecular intermetallic interactions operating at variable distances and (ii) the unambigous assignment of their physical origin to the balanced contributions of unfavorable electrostatic repulsion and favorable gain in solvation energies accompanying the complexation process in condensed phase. An unprecedented model including charge and distance effects provides a novel tool for programming cooperativity in (supra)molecular polynuclear assemblies. In a parallel effort, the related interligand interactions have been explored at a more qualitative level with the development of some remarkable correlations between bond valence sums obtained in the solid state and interligand interactions characterizing the thermodynamic stabilities of the lanthanide complexes in solution. We indeed demonstrated that the more constrained the ligand is in the solid state, the larger interstrand interaction is detected in solution.
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