Tuning The Ligand Field In Seven-Coordinate Dy(Iii) Complexes To Perturb Single-Ion Magnet Behavior

Two mononuclear seven-coordinate Dy(iii) complexes [Dy(TPA)Cl-3] (1) and [Dy(TPA)(OPhCl2NO2)(3)]center dot 0.5CH(2)Cl(2) (2) have been synthesized based on the neutral ligand tris[(2-pyridyl)methyl]amine (TPA) and either the strong strength ligand 2,6-dichloro-4-nitrophenol (Cl2NO2PhOH) or the weak ligand field donor Cl-. The Dy(iii) centers in compexes 1 and 2 have seven-coordinated capped octahedral and capped trigonal prismatic coordination geometries, respectively. Magnetic investigations showed that both complexes display field-induced slow magnetic relaxation. The energy barrier for 2 is higher than that of 1, which is due to the strong ligand field of Cl(2)NO(2)PhO(-)versus Cl-, leading to a larger magnetic anisotropy of 2 as compared to 1.