Slow magnetic relaxation in homoleptic trispyrazolylborate complexes of neodymium(iii) and uranium(iii)

Abstract

Lanthanide- and actinide-based single-molecule magnets are rapidly gaining prominence due to the unique properties of f-orbitals, yet no direct comparison of slow magnetic relaxation of an isostructural and valence isoelectronic lanthanide and actinide complex exists. We present the dynamic magnetic properties of two f-element single-molecule magnets, NdTp₃ and UTp₃ (Tp⁻ = trispyrazolylborate), demonstrating that, although neither complex displays the full anisotropy barrier predicted from its electronic structure, relaxation is slower in the uranium congener. Magnetic dilution studies performed with NdTp₃ reveal that, while intermolecular interactions partially account for the faster relaxation dynamics, they are not uniquely responsible.