Lanthanoid single-ion magnets with the LnN10 coordination geometry.

We have reported two unprecedented single-ion magnets (SIMs) with the homoatomic LnN10 coordination geometry, where the central Ln (Ln = Dy(III) or Er(III)) ion is interlocked by two pentadentate ligands (N5) affording a low symmetry polyhedron. Studies of dynamic magnetic behaviours show an effective energy of 79(4) K for [Dy(N5)2](3+) and 59(4) K for [Er(N5)2](3+), respectively.

Efficient enhancement of magnetic anisotropy by optimizing the ligand-field in a typically tetranuclear dysprosium cluster.

The perturbation to the ligand field around the lanthanide ion may significantly contribute to the magnetic dynamics of single molecule magnets. This can be demonstrated by two typical Dy4 cluster-based single molecular magnets (SMMs), [Dy4X2(µ3-OH)2(µ-OH)2(2,2-bpt)4(H2O)4]X2·2H2O·4EtOH (X = Cl and Br for and , respectively), which were constructed by using 3,5-bis(pyridin-2-yl)-1,2,4-triazole (2,2-bptH) as the polynuclear-chelating ligand. Alternating-current (ac) magnetic susceptibility measurements show that the energy barriers in complexes and were immensely enhanced by comparing with our previous work due to the optimization of the ligand field around Dy(III) ions. Remarkably, their high thermal active barriers at 190 K () and 197 K () under a zero applied external dc magnetic field are also among the highest within the reported tetranuclear lanthanide-based SMMs.