Sustainable biphasic catalysis by confinement into well-defined amphiphilic nanoreactors

Work package:
In the context of sustainable development, it is now essential to consider the recovery and recycling of catalysts in order to improve energy efficiency, limit environmental impact and lower the cost of catalytic processes, especially when rare metals are involved. Micellar biphasic catalysis between an aqueous phase and an organic phase thus offers a very interesting solution but suffers from several disadvantages, such as swelling of the micelle by the solvents/reagents, which can lead to the formation of stable emulsions, preventing good recycling. A very promising solution is to develop "core-shell" nanoreactors by controlled polymerisation and final cross-linking of the micelle. These are composed of a hydrophobic core (cross-linked in the centre) where the catalysts are located and a hydrophilic peripheral layer ensuring solubilisation in water.[1] The aim of this project is to apply this methodology to rhodium(I) [1] and gold(I) [2] catalysis, which have both proven to be very powerful tools for the formation of molecules of interest from relatively simple substrates, but whose recyclability is still a limitation to their wider use. The first step will be to synthesise polymerizable complexes with N-heterocyclic carbene (NHC) ligands[1d] possessing a functional group adapted to the core of nanoreactors. They will then be incorporated into the nanoreactors: either by reversible addition-fragmentation chain transfer (RAFT) polymerisation in water, or by direct insertion into the core of “blank” nanoreactors via non-covalent interactions. They will finally be evaluated in aqueous biphasic catalysis for hydrogenation (Rh) and cycloisomerization and hydroarylation (Au) reactions. This multi-disciplinary internship will provide skills in organometallic chemistry, synthesis and polymerization. The use of air-sensitive compounds will involve work under an inert atmosphere (use of Schlenk techniques, vacuum/argon ramp) and this multifaceted subject will call upon various characterisation techniques such as multinuclear and multi-dimensional NMR, mass spectrometry, dynamic light scattering (DLS), transmission electron microscopy (TEM).