| As a hot research issue of new functional materials, molecular magnets have provided substantial research objects and model compounds to the development of magnetic chemistry. One-dimensional magnetic unit has attracted considerable attention because it possesses infinite spin ground state and shows single-chain magnet (SCM) behavior with high energy barrier and high transitional temperature. Meanwhile, linking the SCM chains into framework via covalent coordination bonds may construct more robust materials with multifunctions. In this thesis, we designed and synthesized three families of molecular magnetic materials based on CoⅡ/LnⅢ single-chains, and explored their magnetic properties. The highlights of this work are as following:1. Using Co ion as spin carrier, we synthesized a water-bridged cobalt chain, which were further linked via a long linker of dicarboxylic ligand to construct a three-dimensional (3D) cobalt coordination polymer. Magnetic study revealed that this coordination polymer showed interesting SCM behaviour with weak ferromagnetic interactions.2. Three 2D LnⅢ coordination polymers {[Ln2(2dmepda)2 (μ3-OH)2-(H2O)]·H2O}n (Ln= TbⅢ, DyⅢ, HoⅢ) with 2,2-dimethylpentanedioic acid (2dmepda) as ligand were synthesized by hydrothermal method, which contained interesting ladder-like lanthanide hydroxide chains. The LnⅢ ions were all-oxygen coordinated with D2d symmetry. Magnetic study of the coordination polymer based on DyⅢ ions exhibited slow relaxation of the magnetization with a large energy barrier of 112 K, τ0 of 1.42×10-8 s and two relaxation pathways resulting from the complicated magnetic structure.3. Two LnⅢ coordination polymers [Ln2(2dmepda)3]n (Ln= DyⅢ, HoⅢ) were synthesized and characterized. These 3D coordination polymers were constructed by carboxylate bridged LnⅢ chains. The two LnⅢ ions in an asymmetric unit of each complex were all-oxygen coordinated with D2d and C2v symmetry. We also investigated the magnetic properites of the two coordination compounds. |
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