Synthesis, Structure And Magnetic Properties Of 3d/4f Polynuclear Metal Complexes

In this thesis, ten new polynuclear complexes have been synthesized by the reactions of Schiff-base ligands with transition metallic and/or lanthanides ions. The crystal structures of the compounds were determined by X-ray cry stallographic methods, and some of them were characterized by element analyses, IR and DC/AC magnetic susceptibility. This thesis could be divided into four chapters:1,A series of binuclear rare earth complexes have been synthesized using Schiff-base ligands. The crystal structures of the compounds were determined by X-ray crystallographic methods.2,Two tetranuclear complexes [Ni4(H2L)4 (CH3OH)4] (7) and [Cu4(H2L)4] (8) were obtained and structurally characterized, and the magnetic properties of the Ni" complex was studied in further. Magnetic studies indicated weak ferromagnetic behavior for the complex.3,Two remarkable diabolo-shaped nonanuclear Dy9 and Ho9 compounds were obtained by the self-assembly between a multidentate ligand and lanthanide ions. The crystal structures of the compounds were determined by X-ray crystallographic methods, and the magnetic properties of the Dy9 complex was studied in further. Alternating current (ac) susceptibility measurements reveal that compound 9 does not exhibit any out-of-phase ac signal. The assembly of two square pyramidal pentanuclear units via the apical metal center may dramatically reduces the effective anisotropy of the molecule, thus resulting in the absence of slow relaxation despite the strong anisotropy of individul Dy5 unit.