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Place Amphi Dorothy Hodgkin
Title
Abstract
Hemiindigoids are photoswitches inherently isomerizable solely upon visible light irradiation. By associating them with a glycosidic moiety within a photoswitchable glycomacrocycle (PGM), it is possible to combine the photochromic properties with the chirality of the sugar, while taking advantage of the functionalization versatility and natural abundance of carbohydrates. Building on previous results obtained in our laboratory, we successfully synthesized, via a one-pot double CuAAC reaction, two novel GMPs, one containing a hemiindigo (HI) and the other a hemithioindigo (HTI) as the photochromic unit, a first to date. Acyclic photoswitchable glucosides were also synthesized in both series. The investigation of the photophysical, photochemical, and chiroptical properties of the majority of the synthesized compounds demonstrated that the N-substitution of HIs enhances photostability at the expense of emission properties. A significant increase in photoconversion quantum yields was measured for PGM-HI, along with a chirality transfer between the glucosidic moiety and the photochromic unit, which was also observed for PGM-HTI. HTIs exhibit absorption maxima at slightly higher energies than HIs, yet still within the visible region. Preliminary results concerning the acyclic molecules as chiral dopants in liquid crystals are promising and confirm the feasibility of using HIs/HTIs for this application.
PhD supervision
- Director: Pr. Joanne Xie, Professor, PPSM, ENS Paris-Saclay
Members of the jury
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Mickaël MENAND, Associate Professor, Sorbonne Université, Reviewer
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Guy ROYAL, Professor, Université Grenoble Alpes, Reviewer
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Stéphanie NORSIKIAN, Research Director, CNRS - Université Paris-Saclay, Examiner
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Christophe COUDRET, Research Director, CNRS - Université de Toulouse, Examiner