Design And Synthesis Of Mononuclear Rare Earth Schiff Base

In this thesis, a series of(11) lanthanide-based 3d-4f Single-Molecule Magnets built by Schiff-based ligands and diamagnetic Zinc(II) ions and lanthanide(III) ions are synthesized and ten of them display Single-Molecule magnetic behavior. Through tuning molecule symmetry by modulating the coordination environments to control the ligand field and study the correlations between single-molecule magnetic behaviour and structure.The main contents include the follows:1. A class of complexes built by ligands(H2L1 H2L2, H2L3, H2L4, H2L5), with transition metal Zn(II) and Dy(III) ions were designed and synthesized, t heir structures were determined, being the Zn-Ln type 3d-4f complexes with th e formulas: [(L4Zn)2Dy(OAc)Cl]·Zn Cl3·3H2O(1), [(L4)3Zn2(OH)3Dy3Cl4]·4CH2Cl2(2), [(L1Zn)2Dy Cl3](3), [(L3Zn)2Dy(OAc)Cl2]·CH2Cl2(4), [(L3Zn)2Dy Cl3]·0.5C H3CN(5), [(L2Zn)2Dy(H2O)Br2]·Zn Br4(6), [(L2Zn)2Dy(SCN)3](7), [(L5Zn)2Dy(OAc)Cl·Zn Cl3·CH2Cl·3H2O(8). All of them show slow magnetic relaxation be havior, in which complex 3 shows higher anisotropy energy barrier(Ueff) being 398 K and blocking temperature being 8 K.2. A class of complexes constructed by ligands H2 L, Dy(III) and transition metal Co(II) and Zn(II) ions [(L2Co)Dy(acac)2Br2]·CH2Cl2(9),[(L2Zn)Dy(acac)Cl](10) were designed and synthesized and their structures were determined. All of them show slow magnetic relaxation behavior and the complex 9 shows higher anisotropy energy barrier(Ueff) being 151 K and blocking temperature being 4 K.3. A “three arms” trinuclear complex [(L6Zn)2Dy Cl]·CHCl3·Me OH(11) formed by ligands H3L6, Dy(III) and Zn(II) ions was synthesized, and the single molecules magnetic properties were investigated.