Design And Magnetic Investigation Of Air-stable Dysprosium Single Molecule Magnets

Hysteresis and slow magnetic relaxation behavior can be observed below the blocking temperatures in types of coordination complexes with magnetic bistable state known as Single-Molecule Magnets(SMMs)which connect microscopic spins to macroscopic magnetic materials and show great potentials in high-density information storage and molecular spintronics.In this thesis,DyⅢ ions are selected as the spin center to construct high-performance SMMs with good air stability,which aims to provide new clues for realizing above applications.More details are as follows:(1)Double-decker DyⅢ macrocycle SMMs with Hula-hoop-like geometries:With the help of Oblate-Prolate Model combined with the strategies toward suppressing quantum of tunnelling magnetization(QTM),a pair of air-stable double-decker DyⅢ macrocyclic enantiomers were designed and prepared using hexaazamacrocycle and fluoride as the equatorial and axial ligands,respectively.Magnetic investigations revealed the strong intramolecular ferromagnetic coupling and two-step relaxation of magnetization.(2)Peroxide-bridged dinuclear dysprosium macrocycle SMMs:A pair of air-stable double-decker DyⅢ macrocyclic enantiomers were successfully synthesized using hexaazamacrocycle and sterically encumbering phenolate as the equatorial and axial ligands,respectively,and the peroxide as bridging ligands.The introduction of peroxide ions enhances the rigidity of molecular skeleton and induces the intramolecular ferromagnetic coupling.(3)Single-Molecule Toroics(SMTs)based on[Dy3]motif:With[Dy3]as the basic units,three SMTs with the same peripheral ligand and different topologies were synthesized by controlling reaction conditions.The coupling of two[Dy3]motifs improves the SMM properties,which provides a new clue to modify topological structures of SMTs and construct covalently bonded[Dy3]polymers.