| The design of new coordination metallic complexes,which have interesting structures and useful physical properties,has been a goal pursued by chemical researchers.Among them,molecular based magnets are important branches of this field,such as single molecular magnets(SMMs)and single chain magnets(SMMs),which have interesting magnetic properties and are closely related to molecular topological structure.However,this field is still in the preliminary stage of research,and there are few experimental synthesis and test characterization for reference,at present.This lack of in-depth research and theoretical analysis has led to a lack of systematic understanding of the correlation between magnetic properties and complex structures.So it prompts the researchers to study magnetic-structure correlation for the purpose of deepening the understanding of magnetic structure-activity relationships and improving the magnetic properties.Our interest in this research field is the heterotrimetallic complexes in which three different metal elements are included in one molecular unit,which could show a fascinating structural pattern.The regulation of the three metal elements can control the coordination structure and spatial distribution of each metal ion,and further adjust the magnetic interaction between different spin carriers.In addition,the heterotrimetallic system combines the properties of three different metals,so it can be designed as multifunctional materials with different properties.Schiff base ligands have the advantage of multiple coordination centers,so Schiffbase ligands have become one of the most important methods for the construction of heterotrimetallic complexes.In this method,two metals are embedded in Schiffbase ligands and then inserted into the third metal based on the charge equilibrium effect.By using this method,different kinds of OD polynuclear clusters ID chains and 2D reticular structures can be constructed.With the aid of the magnetic anisotropy of 4f lanthanide metal ions,some of them exhibit the properties of single molecule or single chain magnets,which will lay a foundation for the design of multifunctional molecular based magnets in the future.In combination with what we mentioned above,three ligands were constructed from ethylenediamine with 2-hydroxy-3-methoxybenzaldehyde(1:2),1,3-diamino-2-propanol with 2-hydroxy-3-methoxybenzaldehyde(1:2)and ethylenediamine with 2-hydroxy-3-methoxybenzaldehyde(1:1),respectively,CU(OAc)2 or Cu(ClO4)2 and Ln(NO3)3·6H2O was embedded into them,then reacted with K3[M(CN)6](M = Cr?,Fe?,Co?)or[W(CN)8]3-.Finally,we successfully synthesized 3 new 3d-4f-5d and 11 new 3d-3d'-4f complexes and completed the related characterization:1.{[Cu2(L1)2Nd(H2O)][W(CN)8]}n· nCH3CN·2nH202.{[Cu2(L1)2 Sm(H20)][W(CN)8]}n·3nH203.{[Cu(L1)Dy(H20)5][W(CN)6]} ·2H204.{[Cu(L1)Dy(H20)4][Co(CN)6]} ·CH3OH·6H205.{[Cu(L2)Gd(H20)3][Cr(CN)6]} n·2nH206.{[Cu(L2)Gd(H20)3][Fe(CN)6]}n·4nH207.{[Cu(L2)Tb(H20)3][Cr(CN)6]}n·2nH2o8.{[Cu(L2)Tb(H20)3][Fe(CN)6]}n·2nH209.{[Cu(L2)Dy(H20)3][Co(CN)6]}n·4nH2O10.{[Cu(L2)La(H20)3][Fe(CN)6]}n·4nH2011.{[Cu(L3)Gd(H20)4][Co2(CN)6]} n· 4nH2012.{[Cu(L3)Ho(H20)4][Co2(CN)6]}n·4nH2013.{[Cu(L3)Tb(H20)4][Co2(CN)6]}n·nCH3OH·3nH2014.{[Cu(L3)Dy(H20)4][Fe2(CN)6]} n· 4nH20We have studied the structure and magnetic properties of 14 complexes by elemental analysis,X-ray single crystal diffraction,infrared spectroscopy and magnetic properties at low temperature.The results of structural analysis show that the complexes 1-2?5-14 have one-dimensional chain structure and complexes 3-4 have zero-dimensional trinuclear metal clusters.Due to the thermal stability of the sample,we have not obtained the magnetic data of the complex 8,9,11,14.The structure and magnetic properties of the remaining 10 complexes were studied.The molecular units of the complex 1-3,5-7,10 contain three different spin centers,1-2,5-7,10,which exhibit weak antiferromagnetism coupling,while complex 3 exhibits weak ferromagnetic coupling.The complex 4,12-13 contains two different spin-center with antiferromagnetic coupling,and 4,13 has a slow magnetic relaxation process,which shows a certain SMMs or SCMs magnets behavior.From the structure-activity relationship analysis of the 10 complexes it can be concluded that the final magnetic properties are greatly affected by the single ion effect and magnetic anisotropy of lanthanide metal ions,and the magnetic anisotropy of the complex molecules is greatly affected by the magnetic exchange between d-f spin centers.The experimental work and the analysis of the structure and magnetism of the complexes will play a positive role in the development of this field.It also promotes the research progress of the structure-activity relationship of complexes. |
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