Subcomponent Self-Assembly of Rare-Earth Single-Molecule Magnets

A family of lanthanide complexes has been synthesized by the subcomponent self-assembly methodology. Molecular architectures, which were stable in solution and under ambient conditions, were designed by the in situ formation of ligands around lanthanide ion templates. Magnetic studies indicated that, despite the low C₂ symmetry, 1 and 2 display single molecule magnet (SMM) behavior, with 1 exhibiting an effective energy barrier of the relaxation of the magnetization U_eff/k_B = 50 K and the pre-exponential factor τ_o = 6.80 × 10^–7 s. Step-like features in the hysteresis loops indicate the presence of quantum tunneling of the magnetization (QTM).