A mononuclear nine-coordinated Dy(iii) complex exhibiting field-induced single-ion magnetism behaviour.

A new mononuclear Dy(iii) complex, with the formula [Dy(Hcpt) 3 ]·2H 2 O (1), has been successfully prepared via self-assembly between Dy(iii) ions and 2-cyano- N '-(1-(pyridin-2-yl)amido)acetyl (Hcpt) ligand. X-ray diffraction study shows that the Dy(iii) ion is nine-coordinated by three Hcpt ligands with a tridentate chelating mode, leading to an approximately monocapped square-antiprismatic ( C 4v ) geometry. Magnetic data analysis demonstrates that 1 performs field-induced slow magnetic relaxation with a relaxation barrier of 97.90 K, due to the quantum tunneling effect suppressed upon a static dc field of 2000 Oe. To deeply understand the magnetic behaviors, the relaxation mechanisms and magneto-structure relationship are rationally discussed using ab initio calculations as well.