| Molecular-based magnetic materials are a type of chemical synthesis methods that coordinate paramagnetic ions（including transition metal ions and rare earth metal ions）or diamagnetic organic ligands and free radicals through self-assembly,which is a molecular solid material with magnetic and physical characteristics formed by bonding.Due to the characteristics of the cyanide group atoms,it has broad application prospects in the fields of aerospace materials,storage materials,microwave materials,photomagnetic and electromagnetic materials,and has become one of the research hotspots in many disciplines such as chemistry,materials,and physics.The distance between them is easy to form a conjugated system,which is conducive to the transfer of magnetic interactions.Therefore,as an important part of molecular-based magnetic materials,cyanide bridging ligands are loved by scientists.The spin-crossing complex can achieve spin switching by pressure,light,temperature and other external factors around room temperature.It is the closest molecular-based magnetic material that can be most easily applied to real life.Therefore,it has broad application prospects in the fields of information storage and molecular switch.The main purpose of this paper is to explore the effect of changing an assembly group on the structure and magnetism of the complex.The main contents of this paper are as follows:1.A series of six new complexes of heterobimetal cyanide were designed and synthesized by using an amine copper compound[Cu（dmpn）2]2+as the assembly chain segment,and polymetallic acid salts containing different number and arrangement of cyanogenbridginggroupsastheconstructionunit.{[Cu（dmpn）2]2[Fe（bpb）（CN）2]}[Fe（bpb）（CN）2]（Cl O4）2.2H2O（1）,[Cu（dmpn）2][Fe（bbp）（CN）3]n.0.5n DMF.2.5n H2O（2）,{[Cu（dmpn）2]1.5[Cr（CN）5（NO）]}n.3n H2O（3）,{[Cu（dmpn）2]2[Fe（CN）6]}n.10n H2O（4）,{[Cu（dmpn）2]4[Mo（CN）8]2}.CH3CN.2H2O（5）,{[Cu（dmpn）2]4[W（CN）8]2}.CH3CN.2H2O（6）.The six complexes were characterized by elemental analysis,infrared spectroscopy,powder and single crystal X-ray diffraction.Structural analysis revealed different structural types of complexes 1-6,from discrete polynuclear entity（1）to one-dimensional single chain（2）to two-dimensional（3,5 and 6）and three-dimensional（4）networks,clearly indicating the important role of building blocks in tuning the structures of the target complexes.We have reported the magnetic properties of cyano bridged complexes through experimental studies and theoretical simulations,revealing the ferromagnetic or antiferromagnetic coupling between low spin Fe（Ⅲ）and Cu（Ⅱ）ions,and the antiferromagnetic interaction between cyano bridged Cr（I）and Cu（Ⅱ）ions.2.We prepared[PPh4]2[Fe（2-CH3im）（CN）5]·2CH3OH（1）and（PPh4）2[Fe（CN）5（imidazole）]·（imidazole）·H2O（4）and characterized based on their structures,using this as the precursor to assemble with Mn compounds,four cyanide bridgedmagneticcomplexesweredesignedand prepared.{[Mn（bipy）（H2O）]2[Fe（2-CH3im）（CN）5]2}n·2n CH3OH·2n H2O（2）,{[Mn（MAC）][Fe（2-CH3im）（CN）5]}n·n CH3OH·2n H2O·n DMF（3）,{[Mn（L）（H2O）]3[Fe（CN）5（imidazole）]}（Cl O4）（5）,{[Mn（MAC）][Fe（CN）5（imidazole）]·CH3OH}n（6）,The structure and magnetic properties were characterized.The results of X-ray data analysis show that the complex 2 has a stepped double chain structure and complex 3 has an ideal single chain structure,which is caused by different space potential resistance effects.Through the study of their magnetism,it is found that there is antiferromagnetic interaction（complexes 2 and 3）between low spin Fe（Ⅲ）ions and high spin Mn（Ⅱ）ions.The results of X-ray data analysis show that the structures of the complexes are cation tetranuclear femn3 solid（5）or one-dimensional infinite chain structure（6）,ferromagnetic coupling and antiferromagnetic coupling in cyanogen bridged FeⅡ-MnⅢ（5）and FeⅡ-MnⅡ（6）units.3.Three Fe（Ⅲ）complexes were s ynthesized by using tetrazole/semi-rigid v-dipyridinamide ligands as the assembly chain segments.{[n-Bu4N][Fe（bipy（ttr）2）2]}·0.5CH3OH·2H2O（1）[Fe（SCN）2（L）2（CH3OH）2]（2）and{[Fe（SCN）2（L）2]·2CH3OH·2H2O}n（3）,and their structures were characterized.The structure and magnetic properties of complex 1 are characterized.Complex 1 is a Fe（Ⅲ）ion coordinated by eight N atoms,which defines a twisted dipteroidal dodecahedron and shows the temperature dependence of incomplete spin crossover behavior.X-ray diffraction results show that the conformations of ligand L in complexes 2and 3 are different.The magnetic properties of the complexes show that the FeⅡ ion center in complex 2 is always in a high spin state,while complex 3 has incomplete spin crossover due to thermal induction. |
PDF Full Text Request