Slow Magnetic Relaxation in Uranium(III) and Neodymium(III) Cyclooctatetraenyl Complexes

Abstract

The synthesis, structure, and magnetic properties of a uranium(III) sandwich complex, [Li(DME)3][UIII(COT″)2] (COT″ = bis(trimethylsilyl)cyclooctatetraenyl dianion), and its coordinatively analogous tetravalent equivalent, [UIV(COT″)2], were investigated. Additionally, a full structural and magnetic comparison to the isostructural and isoelectronic lanthanide complex, [Li(DME)3][NdIII(COT″)2], is provided. DFT calculations reveal that the UIII complex leads to weaker ligand-to-metal donation as compared with the tetravalent equivalent complex. Alternating current magnetic susceptibility results reveal slow magnetic relaxation in both UIII and NdIII complexes. The enhanced magnetic performance of the UIII congener further encourages the use of actinides in the design of single-molecule magnets.