Synthesis And Characterization Of Charge Transfer Compounds And Magnetic Thin Films

Electron transfer（ET）is a well–known phenomenon in nature,from basic plant photosynthesis to material science fields,such as catalysis,energy conversion and information processing,are inseparable from charge transfer.In particular,the charge transfer between metal ions can induce significant changes in their spin states,magnetic exchange interactions,intramolecular charge distributions and bond lengths,thereby can be used to reversibly manipulate the magnetic,electric and mechanical properties of compounds through external stimuli such as heat,light and magnetic/electric fields.Owing to these,charge transfer complexes have attracted broad interests from researchers in recent years.In this thesis,on the basis of previous research results,phenanthroline and dpq were selected as auxiliary ligands,and the 4 building blocks were used to synthesis seven different cyano bridged tetranuclear{Fe₂Co₂}compounds,and explored the relationship between their charge transfer behaviors and molecular structures.At the same time,three representative charge transfer complexes were selected to synthesis three magnetic thin films,and it was investigated whether they maintained the original charge transfer behavior.The successful synthesis of magnetic thin films with charge transfer properties has opened up new ideas for the functionalization of charge transfer compounds,which can be widely used in magnetic sensors,magnetic switches and other devices.The following are the main results of this article:（1）Using four different building blocks[Bu₄N][（Tp^R）Fe（CN）₃](Tp^R=Tp,Tp*,Pz Tp,Tp^4–Me),phenanthroline as auxiliary ligand and Co（Cl O₄）₂·6H₂O to synthesis compounds 1–4.These four compounds had similar molecular structures,only the substituents on the building blocks were different.Among them,compound 1 exhibited a paramagnetic state over the entire temperature range,and compound 2–4 exhibited thermally induced charge transfer behavior.Through the study of the structure–activity relationship of these four compounds,it was found that when the auxiliary ligands were the same,the transition temperature of the compounds with different building blocks were Pz Tp>Tp>Tp^4–Me>Tp*.In order to support this conclusion,the compound 5 was obtained by using dpq as an auxiliary ligand.This compound also showed a thermally induced charge transfer behavior,and compared with other reported charge transfer compounds to explore the transition temperature with different structure of the building blocks.Finally,compounds 6–7 were obtained by anion replacement of compound 2.The auxiliary ligands and building blocks of these three compounds were all the same.Only the counterions were different,so they exhibited different charge transfer behaviors.Exploring the structure–activity relationships of the three compounds,it was found that the volume and steric hindrance of the counterion wound directly affect the strength of theπ–πinteraction between molecules,which affects the charge transfer behavior.（2）Three kinds of charge transfer compounds with good solubility and stability were selected from the existing charge transfer compounds,mixed with HPMC,and successfully synthesized three high–quality magnetic thin films through the dip–coating method.It was also proved by variable temperature infrared and variable temperature magnetic susceptibility that these magnetic films still maintained the original photothermally and thermally induced charge transfer behaviors.At the same time,the surface morphology of different sides of the films was observed by scanning electron microscope.The successful preparation of magnetic thin films with charge transfer properties opened up new ideas for the functionalization of charge transfer compounds.