Structures And Magnetic Properties Of4f Single Ion Magnets And2p-4f/3d Complexes

This work focuses on the fascinating research field of lanthanide single-molecule magnets and functional complexes. Thirty-eight complexes have been constructed from the nitrogen-containing ligands and nitronyl nitroxide radicals. The X-ray single crystal structure, IR spectra, electronic spectra, magnetic measurements and fluorescence spectra have been investigated.1. Three series of mononuclear lanthanide complexes have been synthesized by using different nitrogen-containing ligands of pz, bpy and terpy. The magnetic measurements showed that the DyⅢ complexes of pz and bpy exhibit slow magnetic relaxation, and the DyⅢ complex of pz is the first mononuclear single-molecule magnet containing the monodentate N-heterocyclic donor ligand with D2d-dodecahedron local symmetry. The luminescence spectra in both visible and NIR regions, the fluorescence lifetimes, and quantum yields of the complexes were also studied.2. Four series of4f-2p complexes have been synthesized by NITNapOMe,2MeONIT, NITPh-3-Br-4-OMe and NITmNO2radicals. Especially for2MeONIT, the DyⅢ and GdⅢ complexes have mononuclear tri-spin structures with the P3121chiral space group, while the TbⅢ complex has1D chain structure. The magnetic measurements rough evaluated the magnetic interactions between LnⅢ ions and other spin carriers within these complexes, fluorescence measurements showed the DyⅢ, TbⅢ and EuⅢ complexes based on2MeONIT, NITPh-3-Br-4-OMe radicals exhibit the characteristic fluorescence spectra of the lanthanide ions.3. Two rarely reported hetero-tri-spin2p-3d-4f complexes have been synthesized by using the nitronyl nitroxide radical with one functional coordination site (NIT-4Py).4. To study how the steric hinderance effects and the coordination groups of nitronyl nitroxide radicals affect the structure of transition metal-radical complexes, by using NITPh-3-Br-4-OMe and NITmN02, two CuⅡ-radical complexes were obtained; one is a five-spin structure with radical having smaller steric hinderance, the other is a tri-spin compound with radical having the bigger steric hinderance. The magnetic studies showed that former has stronger antiferromagnetic interaction between CuⅡ ion and radicals due to the nitroxide occupies an equatorial position in the coordination environment of copper(Ⅱ), latter has weaker ferromagnetic interaction due to the nitroxide occupies an axial position. In addition, the EPR spectra are also studied.