Description du sujet de thèse

Polyoxometalates (POMs) are discrete, water-soluble metal oxide polyanions typically comprising Mo or W metals in their highest oxidation state (MVI). The incorporation of electrophilic preformed sulfur-containing cationic units such as [MoIV3S4(H2O)9]4+ (abbreviated hereafter as {Mo3S4}4+) into lacunar POMs has led to a new class of polyoxothiometallate compounds, thio-POMs.
Recently, we have shown that thio-POMs are among the most efficient catalysts for proton reduction (or HER: hydrogen evolution reaction) when combined with photosensitizers. This exceptional efficiency is due to a synergistic effect between the redox properties of the electron-poor POM, acting here as an electron/proton collecting unit, and the catalytic properties of the {Mo3S4}4+ unit.
This thesis project aims at designing photoactive systems combining complementary inorganic molecular entities, thio-POMs as HER catalysts, and electron-rich octahedral metal clusters (CLUSs) as efficient, robust and cheap photosensitizers. The host-guest supramolecular approach using commercial cyclodextrins (CDs) as water-soluble polytopic connectors provides a simple and inexpensive synthetic self-assembly route for compartmentalization of functional units with optimal contact in space within the tandem.

Contexte de travail

This PhD is part of an ANR project, CLUSPOM-H2. The PhD student will work with a team of four experienced and internationally recognized researchers in the field of synthesis, characterization and studies of the properties (structural, redox and physicochemical) of POMs and thio-POMs. This thesis is part of a multidisciplinary collaborative research project involving two other academic partners (ISCN-Rennes and ISMO-Orsay) and the PhD student will interact with its members in the context of joint studies. Collaborations with theorists, spectroscopists and chemists are envisaged to cover complementary competences in the fields of molecular sciences and inorganic materials, advanced multi-scale spectroscopy, quantum chemistry and photocatalysis.
The thesis will be carried out in the ILV laboratory, UMR 8081 belonging to the University of Versailles St-Quentin en Yvelines. This laboratory is composed of 3 teams, and the PhD student will integrate the MIM group (Molecule-Interactions-Materials). The activity of the MIM gathers transversal and complementary competences going from the synthesis of molecular objects or materials to their in-depth study via specific tools of structural analysis by X-ray diffraction or NMR spectroscopy. Our laboratory has a wide range of equipment (NMR, XRD, MS, electrochemistry, UV-Vis, micro-GC, etc.) necessary to carry out this thesis in the best conditions.

Contraintes et risques

Classic risks related to the handling of chemical products.