A seven-coordinated Dy-III single-ion magnet with C-2v symmetry constructed by a multidentate Schiff-base ligand

Two isostructural mononuclear lanthanide complexes [Ln(H2L)Cl-3](Ln = Dy(1), Tb(2), H2L = 6,6 '-(((oxybis(2,1-phenylene))bis-(azanylylidene))bis(methanylylidene))bis(2-methoxyphenol)) were synthesized by solvothermal reaction. In both complexes, the Ln(III) ions are seven-coordinated with a LnO(4)Cl(3) coordination core in the C-2v symmetry. Magnetic measurements reveal that Dy-III complex 1 shows field-induced two-step magnetization relaxation processes with U-eff = 53.47 K (slow relaxation) and 26.94 K (fast relaxation), respectively. The analysis of energy levels and eigenstates suggests that the mixed ground state doublets result in the field induced single-ion magnet behaviour of complex 1. In addition, the magneto-structural correlation, including the easy magnetic axis of Dy-III ion, was further discussed based on an electrostatic model calculation. This work gave another example of designing low-coordinated Ln-SIMs by utilizing a multidentate Schiff-base ligand with large steric hindrance.

Automated summary

Two isostructural mononuclear lanthanide complexes were synthesized by solvothermal reaction. Magnetic measurements revealed unique magnetization relaxation processes in the Dy-III complex, indicating a field-induced single-ion magnet behavior. The magneto-structural correlation was further discussed based on an electrostatic model calculation.