Rare Earths-Critical Metals for Future Applications

Principal Investigator

This is a new project. This project aims to develop unusual oxidation state rare earth metal (critical metal) organic complexes with high properties (e.g. reactivity, luminescence, strong magnetism), and small molecule activation of these new species. The project expects to advance knowledge of rare valent rare earth chemistry and to enhance the understanding of direct reactions and C-F activations and rare earth complexes involving organic radical anions. Expected outcomes include expansion of tetravalent lanthanoid chemistry and new structures, reactivity, and magnetic properties. Significant benefits are the applications of Australia's abundant rare earths in catalysis as well as the development of new extraction and separation techniques. The results for LnIV will provide key information for the isolation of stable lanthanoids (IV) complexes with high oxidizing abilities, which is important for the expansion of tetravalent lanthanoid chemistry and its applications in catalysis as well as the development of new separation techniques. Divalent and mixed valent rare earth compounds will expand their synthesis and application. All of them require considerable synthetic innovation and would be a major contribution to knowledge and would open exciting reaction chemistry. The innovation is to build –C-F-Ln bonds and induce C-F activation of fluorine substituted ligands by the direct reactions or redox transmetallation RT reactions from free rare earth metals. The redox-active ligand is a particularly attractive linker to promote magnetic coupling in lanthanoids resulting in complexes displaying exchange coupling and single molecule magnet behaviour. These radical-bridged complexes can be accessed using simple N/O supporting ligands. These findings will pave the way for the synthesis of radical-bridged complexes and suitable tuning of the supporting ligand should lead to improved magnetic communication, exchange-coupled SMMs, and understanding the magnetic properties of the 4f-block metal compounds. The main benefits of the project are advancement of knowledge of rare earth chemistry, especially of highly reactive metal-organic compounds, maintenance of Australia’s position as one of the leaders in this field. Knowledge and innovations acquired in this research will facilitate advances in use of Australia's abundant rare earths in chemical manufacture, catalysis, and recycling. It will add value to Australia’s abundant rare earth resources by providing a base for downstream applications. Moreover, the production of rare earth complexes with improved magnetic properties provides an opportunity for advanced manufacturing in Australia’s fine chemicals industry. The most expensive items are rare earth metals for the synthesis of tetravalent rare earth complexes. e.g. Eu $1200/20g, Yb $1252/100g, Dy $939/100g, Tb, $1565/50g, Pr 782/100g, Lu and Tm are much more expensive. Other necessary expensive reagents include pentafluorobenzene $688/500g, 2,6-Difluoroaniline 349/100g, 2,6-Diisopropylaniline $320/100g, 2,3,4,5-Tetrafluoroaniline $195/25g, 2,3,5,6-Tetrafluoroaniline $276/25g, 2,3,4,5,6-Pentafluoroaniline $342/100g, triethyl orthoformate $277/1L, pyrrole $189/100ml, 3-Pentanone $100/1kg needed to prepare organometallic reagents and ligands. Other important reagents include tris(4-bromophenyl)ammoniumyl hexachloroantimonate $105/5g (the oxidizing agent), Benzophenone ($122/1kg), 4,4´-Dipyridyl ($202/25g), iodine ($147/100g), K/Na metal, et al. A supply of deuterated solvents is needed for NMR spectroscopy, e.g. C6D6 ($495/100g) and C4D8O ($477/10g). Microanalyses are a major cost for a synthetic project as the analyses are determined in London (air-sensitive sample $45/C, H, N) and SQUID measurement will be determined at EPSRC National EPR Facility University of Manchester ($160/h).

01 Jun 2025 - 31 Dec 2025

N/A