| Single-molecule magnets have important research significance in the new generation of high-density information storage materials and theoretical research due to their magnetic bistable and independent magnetic domain properties.Among them,the two metal ion centers of the dinuclear rare earth single-molecule magnets are mainly connected by bridging oxygen or nitrogen atom.In addition,due to the existence of magnetic interactions and different magnetic anisotropy axes in dinuclear single-molecule magnets,it exhibit different magnetic properties,which can promote the further development of single-molecule magnets.Therefore,In this paper,seven Schiff base ligands and three oxazole ligands were synthesized,and seven novel D2d configuration of the dinuclear dysprosium complexes were synthesized by selecting mixed Schiff base ligands and oxazole ligands and introducing bridging ligands under certain conditions.Combining magnetic charcterization and theoretical calculations,the magneto-structural correlations is deeply explored.The specific research is as follows:1.Using 2-hydroxy-3-methoxybenzaldehyde as a raw material,it reacts with p-tert-butyl o-aminophenol and 2-amino-4,6-di-tert-butylphenol to obtain the corresponding ligands H2L1and H2L3.Ligands HL2 and HL3 were obtained by oxidation-reduction of silver nitrate with Schiff base ligands H2L1 and H2L3,respectively.the Schiff base ligand and the oxazole ligand are reacted with the rare earth dysprosium salt at the same time to obtain two dinuclear dysprosium complexes with similar structures,Dy2(L1)2(L2)2(CH3CH2OH)(CH3OH)(1)and Dy2(L1)2(L3)2(CH3OH)2·1.5CH3OH(2).Their structure and magnetism were investigated.Combined with theoretical calculations,the different orientation of the magnetic anisotropy axis,resulting from the different spatial arrangements of the mixed ligands in the core structure.The small exchange energy,antiferromagnetic exchange interaction and non-parallel alignment of the main magnetic axes between Dy1 and Dy2 in 1 and 2 may be the reasons behind the low experimental extracted effective energy barrier for the magnetization reversal.2.We synthesized six ligands H2L4,H2L5,H2L6,HL7,H2L8,H2L9,and characterized by NMR.Five dinuclear dysprosium complexes were obtained by the reaction of five ligands with different anionic dysprosium salts under the action of auxiliary ligands 2,6-dimethoxyphenol(L'),HL7 and oxalate,[Dy2(L4)2(L')2(CH3CH2OH)2](3),[Dy2(L5)2(L')2(CH3OH)2](4),[Dy2(L6)2(L7)2(CH3OH)2](5),[Dy2(L8)2(CH3COO)4]·H2O(6)and[Dy2(L8)2(C2O4)(CH3CH2OH)2](7).The crystal structure of complexes 3-7 were analyzed respectively.Combining magnetic charcterization,the?MT diagram shows that there is a weak ferromagnetic interaction between 3 and 4,and the MH curve does not overlap,which indicates that 3 and 4 have strong magnetic anisotropy. |
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