Design,Syntheses And Magnetic Properties Of Dysprosium And Iron Group Complexes

Because of the unique molecular magnetic properties,single-molecule magnets(SMMs)have attracted great interest with the collective aim of their practical applications in ultrahigh-density information storage,quantum computing and molecular spintronics.In this thesis,several novel Ln-based and Iron-based complexes were designed and synthesized by using N,O-riched organic ligands,and their structures and magnetic properties were investigated.More details are as follows:1.A novel mononuclear cobalt complex was designed and synthesized based on1,8-naphthopyridine-2-carboxylic acid(HL3).The alternating-current(ac)magnetic measurements showed that the complex exhibited typical single-molecule magnetic behavior with Ueff of 45 K under the 700 Oe applied dc field.Crystal structure analysis showed that the axial O-Co-O angle was close to 180 °,which may be beneficial to the single molecule magnetic behavior.2.Using 4,6-dihydrazine pyrimidine(H2L1)and 8-hydroxyquinoline-2-formaldehyde(HL2)as ligands,two novel complexes,Dy2Cl(1+1)and Dy2Cl(3+1),were successfully obtained by slow solvent evaporation and slow diffusion of diethyl ether at room temperature,and their structures and magnetic properties were analyzed subsequently.The coordination environment of the dysprosium ions in Dy2Cl(1+1)and Dy2Cl(3+1)was different,and the crystal system also changed from orthorhombic to monoclinic system.The magnetic measurements showed that no significant out-of-phase(???)signals were observed for complexes Dy2Cl(1+1)and Dy2Cl(3+1)even the temperature down to 1.9 K.However,obvious frequency-dependence of ??? signals of these two complexes were detected under 700 Oe applied dc field,indicating typical slow magnetic relaxation behavior.3.Using H2L1 and HL2 as ligands,three novel complexes,Dy2-SCN,Dy3-SCN and Dy4-SCN,were synthesized by adjusting the reaction conditions.Dy2-SCN,Dy3-SCN and Dy4-SCN crystalize in the orthorhombic,monoclinic and triclinic space group,respectively.The magnetic measurements showed that the complex Dy2-SCN didn't display slow magnetic relaxation behavior.For complexes Dy3-SCN and Dy4-SCN,slow magnetic relaxation behavior can be observed under 500 and 600 Oe dc field,respectively.