If the f-elements; rare earths and actinides, have many applications in various fields (catalysis, materials for optics, for magnetism, for energy and quantum technologies), major fundamental questions yet remain to be discovered. The nature of the interactions between the f orbitals, which have a low radial extension, and their surroundings is still in question. Indeed, if the buried-character of f-electrons confers their compounds with some of their properties, this particularly harms the description of covalent bonds of φ-symmetry. More specifically, the interaction of two φ-symmetry metallic orbitals, which would lead to the description of φ-bonds, is sorely lacking in the landscape of molecular chemistry. In order to exacerbate the interactions with f- orbitals, we propose to use the argument of symmetry, locking the f orbitals in an ideal configuration, which will make the description of φ-interactions easier to study. We propose to use original large aromatic ligands in order to synthesize compounds of high symmetry. This approach notably differs from the current one, which aims to sterically hinder conventional ligands with large substituents. Once the symmetry is locked, we will vary the electron count and the redox state, as well as the ligand field by modulating the 4f- or 5f-ion used, including transuranic elements. The organometallic synthesis of the these original 4f- and 5f-compounds will be followed by experimental electronic density studies as well as adapted spectroscopy, which will shed light on the interactions of φ−symmetry. Unusual radioelements, uranium and more classical rare earth metal ions will thus lead to an overall assessment of the necessary requirements to enhance the interactions and move towards molecules containing several f-metal ions and a small intermetallic distance. The redox and physical properties of the latter compounds will be engineered with the aim of forming molecules containing metal-metal interactions of φ-symmetry.
Fields of science
- HORIZON.1.1 - European Research Council (ERC) Main Programme