Constructing The Dy(?) Single-ion Magnets Based On The Strong Ligands

Single molecular magnets have broad application prospects in quantum computers,high-density information storage materials and molecular spintronics.Single-ion magnets have become a research hot topic in recent years because of their simple structure and high effective energy barrier.Compared with transition metal ions,lanthanide metal ions have unquenched orbital angular momentum,the mononuclear complexes based on lanthanide metals have very large magnetic anisotropy,resulting in slow magnetic relaxation.This thesis focuses on the construction of Dy(?)single ion magnets based on strong ligands.The main work can be divided into the following three parts:1?Dy(?)-based single-ion magnet with octahedral configurationBy using the oxygen-containing ligands with the strong coordination ability,a six-coordinated mononuclear Dy(?)complex[Dy(Ph₃PO)₃(OPh Cl₂NO₂)₃](1)(Ph₃PO=triphenylphosphine oxide;Cl2NO2Ph OH=2,6-dichloro-4-nitrophenol)with the[Dy O6]octahedral configuration with strong ligand has been successfully synthesized.Magnetic measurements show that complex 1 exhibits slow magnetic relaxation with effective energy barrier of 21.3 K.2?Seven coordinate Dy(?)-based single-ion magnetsIn order to investigate the influence of strength of the ligand field on the magnetic property,the strong strength ligand 2,6-dichloro-4-nitrophenol(Cl₂NO₂Ph OH)and the weak ligand field donor Cl^-were employed to construct two mononuclear seven-coordinate Dy(?)complexes[Dy(TPA)Cl₃](2)and[Dy(TPA)(OPh Cl₂NO₂)₃]·0.5CH₂Cl₂(3)based on the neutral ligand TPA(TPA=tris[(2-pyridyl)methyl]amine).X-ray crystallographic analysis shows that the coordination geometries are the capped octahedron with C_3v symmetry for complex 2 and the capped trigonal prism with C_2v symmetry for complex 3.Magnetic studies have shown that the two complexes field induced slow magnetic relaxation and have different effective energy barriers.The effective energy barrier of complex 3 is 46.5 K,which is higher than that of complex 2.This is due to the strong ligand field Cl₂NO₂Ph O^-.3?Chain-like Ln³⁺-Fe³⁺complex bridged with cyanogenTwo cases of lanthanide metal complexes are successfully synthesized using neutral ligands tris[2-(pyridyl)methyl]amine(TPA)and hexacyanometalate(K₃[Fe(CN)₆])[Dy(TPA)Fe(CN₆)(H₂O)₂]·4H₂O(4)and[Gd₂(TPA)₂Fe₂(CN₆)₂(H₂O)₂]·8.5H₂O(5).Structural analysis shows that the central Dy(?)ion of complex 4 forms one-dimensional chain structure,whereas the central Gd(?)ion of complex 5 has two-dimensional chain structure.