Although current applied processes for extracting uranium in sulfuric, phosphoric and nitric media, are efficient enough to justify their large-scale application, they require improvements to increase their efficiency and reduce their environmental impact. This doctoral project aims to improve these performances by focusing on the liquid-liquid extraction stage. This consists of selectively transferring uranium, extracted after crushing, grinding and leaching rocks, to an oil phase containing a lipophilic ligand compatible with the leachate medium. The ambition here is to develop new extractants analogous to trialkylamines (AMEX process), trialkylphosphines and phosphoric diesters (URPHOS process), and trialkylphosphates (refining). The PhD student will synthesize chiral amphiphilic extractants, derived from bicyclic anhydrides of biosourced alditols (isosorbide, isomannide and isoidide). He will evaluate their affinity towards uranium and their selectivity in the presence of competing ions. He will then characterize the molecular and supramolecular mechanisms of these new extractants (coordination, aggregation) using state-of-the-art methods such as UV, IR, multinucleus NMR, X-ray scattering and neutron scattering. The doctoral training will help the PhD student to integrate easily into academic or industrial environments, particularly in the fields of the nuclear fuel cycle, separative chemistry and formulation. Research will take place in the LTSM laboratory of the Institut de Chimie Séparative de Marcoule, renowned for its expertise in the chemistry and physical chemistry of extractants for hydrometallurgy. The PhD student will benefit from high-quality supervision and a collaborative working environment, surrounded by PhD students, post-docs and engineers, in a serene and stimulating setting.