| Magnetic materials are an indispensable part of people's life,social industry and national defense and military affairs,especially in today's high-density storage and quantum computers.However,the development of traditional magnetic materials has reached the bottleneck,which shows that the minimum particle size has reached the limit,and the storage per unit area and the amount of calculation are difficult to improve by the order of magnitude.Therefore,the exploration of new magnetic materials has become the research focus of researchers.Molecular-based magnets can fill this gap.It has controllable topological structure,anisotropy spin variation,magnetic coupling between metal ions,quantum tunneling behavior,These characteristics can bring the advantages of small volume,fast operation speed,large information capacity and low cost of industrial application,that is to say,they can be used to make the processors of molecular unit memory and quantum computer.There are two categories of molecular-based magnets:low-dimensional molecular magnets and high-dimensional molecular magnets,which include single-molecule magnet?SMM?and single-chain magnet?SCM?.Molecular magnets can show magnetism mainly by using the single electron spin of atoms or ions in the molecule,and its synthesis depends on the branch of coordination magnetochemistry in coordination chemistry.The study of coordination chemistry is based on the coordination of organic ligands with metal ions.With the help of the structural rigidity of organic ligands,the overall structure of coordination molecules,the coordination mode of metal ions and the orbital single electron spin of metal ions are used to synthesize the structure stability.Crystal complexes with excellent properties.The published work on the synthesis of magnetic complexes is based on single-core or binuclear metal ion complexes,and there is a lack of in-depth study on the interaction and structure regulation between metal ions,especially hetero-nuclear trimetallic ion complexes.Therefore,the focus of the study is to synthesize the heteronuclear metal complexes by modifying the organic ligands to regulate the structure of the molecular complexes.The interaction between intramolecular metal ions and molecules is studied and their magnetic structure-activity relationship is explored.The content is to combine three different metal ions into an organic ligand by artificial arrangement and combination,first to prepare d/f bimetallic precursor by chelating,and then to combine the third kind of metal ion by bridge.The idea of this study is to integrate the properties of different metal ions into a molecule and synthesize complex molecules with various structures by electrostatic interaction,covalent bond and hydrogen bond interaction.The complex molecule is prepared by condensation of3-methoxysalicylaldehyde with diamine as organic ligand.The metal ions include the first transition metal ion(CuII,NiII,FeIII,CrIII,CoIII)and lanthanide transition metal ion(PrIII,GdIII,DyIII,TbIII,SmIII,HoIII,NdIII),The structures of molecules include 0-D trinuclear,0-D octanuclear and 1-D complex.Following the above analysis method,this program constructs organic ligand by the condensation between different diamines and o-vanillin.Ni?CH3COO?2·4H2O and Cu?CH3COO?2·H2O are working as first metal ion salt,Hexahydrate lanthanide metal nitrate are working as second metal ion salt,K3Fe?CN6?,K3Co?CN6?and K3Cr?CN6?are working as third metal ion.Different crystallization methods and different equivalent ratios were used for self-assembly reaction.Finally,26 new 3d-4f-3d complexes have been successfully synthesized:1.[Ni?L?Dy?H2O?4][Fe?CN?6]·3H2O2.[Ni?L?Dy?H2O?4][Co?CN?6]·3H2O3.[Ni?L?Dy?H2O?4][Cr?CN?6]·3H2O4.[Ni?L?Ho?H2O?4][Fe?CN?6]·3H2O5.[Ni?L?Ho?H2O?4][Co?CN?6]·3H2O6.[Ni?L?Tb?H2O?4][Co?CN?6]·3H2O7.[Ni?L?Gd?H2O?4][Co?CN?6]·3H2O8.[Ni?L1?Gd?H2O?4][Fe?CN?6]·3H2O9.[Ni?L1?Gd?H2O?4][Co?CN?6]·3H2O10.[Ni?L1?Pr?H2O?4][Co?CN?6]·3H2O11.[Ni?L1?Tb?H2O?4][Cr?CN?6]·3H2O12.[Cu?L3?Gd?H2O?4][Co?CN?6]·3H2O13.{[Cu?L2?]2Gd?H2O?[Fe?CN?6]}2·2DMF14.{[Cu?L2?]2Gd?H2O?[Co?CN?6]}2·2DMF15.{[Cu?L2?]2Gd?H2O?[Cr?CN?6]}2·2DMF16.{[Cu?L2?]2Pr?H2O?[Cr?CN?6]}2·2DMF17.{[Cu?L2?]2Sm?H2O?[Cr?CN?6]}2·2DMF18.{[Cu?L2?]2Sm?H2O?[Co?CN?6]}2·2DMF19.{[Cu?L2?]2Nd?H2O?[Cr?CN?6]}2·2DMF20.{[Cu?L2?]2Pr?H2O?2][Co?CN?6]}n·9nH2O21.{[Cu?L2?]2Pr?H2O?2][Cr?CN?6]}n·9nH2O22.{[Cu?L3?Gd?H2O?][Co?CN?6]}n·8nH2O23.{[Cu?L4?Sm?H2O?3][Co?CN?6]}n·2nH2O24.{[Cu?L4?Pr?H2O?3][Fe?CN?6]}n·2nH2O25.{[Cu?L4?Pr?H2O?3][Co?CN?6]}n·2nH2O26.{[Cu?L4?Nd?H2O?3][Fe?CN?6]}n·2nH2OI also carried out the test of single crystal X-ray diffraction and IR measurements on the crystals of the 26 complexes,and the magnetic properties of the complexes 1-7,14,17,19 and 21.The structure of the complexes shows that the complexes 1-12are trinuclear single molecular structure.The complex 13,19,20,21 is single chain structure,22 is Z type chain structure,and 23-26 is trapezoidal chain structure.The structure can be effectively regulated by changing the experimental method and equivalent ratio.In the aspect of magnetic analysis,the ferromagnetic and antiferromagnetic interactions between metal ions and lanthanide ions have been proved by difference method,and there is obvious anisotropy between transition metal ions and lanthanide metal ions.This paper provides a powerful theoretical basis for the regulation of the structure for metal complexes,and further deepens the study of the magnetic structure-activity relationship of metal complexes. |
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