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Place Amphi Dorothy Hodgkin
Title:
Synthesis and properties of arene-ruthenium(II) complexes bearing photoswitchable azobenzene-derived ligands
Resume:
The external manipulation of molecular systems with light is presently seen as an essential strategy for the spatial and temporal control of events at various scales, leading to “smart” systems with wide applications in fields such as biology, material sciences or catalysis. Metal complexes incorporating ligands with photochromic properties appear as a promising class of compounds for such applications since the inherent electronic, optical or catalytic properties of the metal center can be modulated by ligand photoswitching. The work performed in the context of this thesis essentially focused on the synthesis of azobenzene-derived ligands and their incorporation in ƞ6-arene-ruthenium(II) complexes, as well as the study of their properties by UV-vis absorption spectroscopy, 1H and 13C NMR, XRD analysis and molecular modelling by DFT and TD-DFT.A first family of complexes bearing an o-sulfonamide azobenzene ligand diversely substituted to modulate the steric hindrance was synthesized, and the reversible photo-isomerization properties of the proligands and complexes were investigated. The reactivity of these complexes in the presence of various phosphorous or nitrogen-containing nucleophilic species was also examined. A second family of compounds bearing symmetric azobispyridine ligands was then developed and showed an irreversible Z→E isomerization upon action of a photochemical stimulus. Their reactivity was also tested in the presence of different electrophilic species. Finally, the photoswitching and acido-basic properties of new organic polymers containing azobenzene units in their main-chain were analyzed and correlated with theoretical studies performed on a model molecule.
This work is available online.