Construction And Magnetism Of Cyano-bridged Double-zigzag Molecular Magnets

With the development of information technology,it is difficult for traditional magnetic materials to store high density information due to size effect.Molecular-based magnetic materials such as and single-chain magnets（SMMs and SCMs） can realize the storage function at the level of a single molecule,and their potential high-density magnetic storage function makes them become the focus of scientists in related fields.Cyano-group have strong adjoint ability and small bridging distance,which make them superior in the field of building molecular-based magnetic materials.At present,the construction of molecular-based magnets with single-chain magnets is still a big challenge.In this paper,the double-zigzag chain-like molecular-based magnets with variable structure and magnetic properties are obtained by self-assembly of cyanogen-based construction units and auxiliary ligands with different isosteric resistance with transition metals.A lot of experimental data are accumulated for further study of the structure-activity relationship of magnets and the construction of single-chain magnets.We’ve got several research results:（1）Using tricyanometalates [Bu₄N][Fe（Tp*）（CN）₃] as precursors and tridentate ligand Tp*occupies the three ligand sites of Fe^III and reduces the structural dimension of the compounds.Three one-dimensional double-zigzag molecule-based magnets bridged by cyanide 1-3 were synthesized by self-assembly of nitrogen-containing auxiliary ligands 3-（phenyldiazenyl） pyridine （3-papy） and 3-phenylpyridine （3-bp） with bivalent transition metals Mn^II and Co^II ions.Studie on the magnetic properties of compounds 1-3 showed an intramolecule ferromagnetic interaction.The magnetic properties can be effectively controlled by changing the steric resistance and metal ions.（2）Using tetracyanometalate precursors Li [Fe^Ⅲ（bpy）（CN）₄] and nitrogen-containing ligands 4-（phenyldiazenyl） pyridine（papy）,1,2-di（pyridin-4-yl） diazene（azp）,and 4-phenylpyridine（bp）with bivalent transition metals Cu^II and Ni^II ions,four low-dimensional double-zigzag molecular-based magnets 4-7 were obtained.Spatial steric resistance,metal ions and interchain magnetic interactions make the compounds exhibit diverse magnetic properties.Compounds 4-7 all showed ferromagnetic interaction.Compared with compound 5,compound 6 exhibits a weaker ferromagnetic interaction.Large chain spacing and the introduction of anisotropic metal ion Ni increase the possibility of single-chain magnet behavior,and compound 7 exhibits single-chain magnet behavior.