Local Geometry Symmetry and Electrostatic Distribution Dominated Eight-Coordinate β-Diketone DyIII SIMs

To further explore the correlation among the relaxation dynamics, geometry symmetry and ligand field of Dy-III SIMs, three beta-diketone mononuclear Dy-III complexes, formulating as [Dy(thd)(2)(NO3)(TPPO)(2)] (1), [Dy(tfa)(2)(NO3)(TPPO)(2)] (2) and [Dy(thd)(3)(4-Py)(2)] (3) (thd = 2,2,6,6-tetramethyl-3,5-heptanedione, tfa = trifluoroacetylacetonate, Tppo = Triphenylphosphane oxide and 4-Py = 4-methylpyridine) have been synthesized. Single-crystal X-ray diffractions reveal that complexes 1-3 are all eight-coordinated mononuclear structures with D-2d, C-2v and D-4d local symmetry, respectively. Magnetic analysis reveals that all complexes 1-3 exhibit field-induced single-ion magnets (SIMs) behavior resulted from the mixed eigenstates of ground state doublets. The differences in the results of energy barrier indicate that the local geometry symmetry and electrostatic distribution of Dy-III ions dominate the magnetic property. Furthermore, the relationship between the structure and magnetism of eight-coordinated Dy-III ions SIMs with the SAP N2O6 coordination environment was also discussed via correlation between the anisotropy axis and coordinating geometry symmetry.