Conférence de la Professeure Cornelia Bohne (Victoria)

Titre :  Supramolecular Dynamics and Function for Host-Guest Systems with Increasing Complexity: From Cucurbit[n]urils to Bile Salt Aggregates and  Serum Albumins.

La conférence sera prononcée par la professeure Cornelia Bohne du Département de chimie de l'University of Victoria. Elle sera donnée en anglais. 

Résumé : Supramolecular systems are always reversible and characterization of their dynamics is essential to understand and control their function. The kinetics for the association and dissociation processes of the building blocks of interest are measured using fast kinetic techniques. The characterization of the dynamics of guest binding with cucurbit[n]urils (CB[n]) showed that the exceptionally high equilibrium constants for guest binding are achieved because the dissociation processes are much slower than observed for other macrocycles. The presence of cations, which can bind to the portals of CB[n]s, and the structure of the guest influence the type of mechanism observed for the guest-CB[n] dynamics. Bile salt aggregates are host systems with increased complexity because of the presence of binding sites with different properties. Bile salt aggregates in solution and as gels are excellent hosts to solubilize water insoluble functional guests, such as photochromic compounds. Multiple colors were achieved for photochromic compounds incorporated into bile salt gels eliminating the need for the synthesis of molecules with tethered chromophores. Serum albumins are chiral host systems that were employed to enhance the chiral discrimination of a bimolecular model reaction. Photophysical measurements showed that the highest enantiomeric excess is achieved when the reagent is bound to a protein site for which exchange dynamics of the reagent with the aqueous phase is fast, but once bound the reagent is immobile.

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