Construction And Application Of Multinuclear Lanthanide Complexes Based On Flexible Acylhydrazone Ligands

Coordination chemistry of lanthanide is an important branch of inorganic chemistry,and has made huge progress in catalysis,sensing,luminescence,and magnetism.Compared with mononuclear lanthanide complexes,most of multinuclear lanthanide complexes possess more complicated structures,which results in more challenges in structural construction and application research of multinuclear lanthanide complexes.Therefore,we further designed different bridged acylhydrazone ligands that could self-assemble with lanthanide ions to form five kinds of multinuclear lanthanide complexes based on our previous research.The research on the structure construction,recognition performance,catalytic performance and near infrared luminescence of these multinuclear lanthanide complexes were also studied.This dissertation is divided into the following five chapters:Chapter 1:The research background of multinuclear lanthanide coordination chemistry was briefly introduced.And then the structure construction of multinuclear lanthanide complexes were also introduced.At the same time,the research progress of multinuclear lanthanide complexes in luminescence recognition,chiral recognition and catalytic applications were briefly reviewed.Chapter 2:A novel chiral acylhydrazone ligand H₂L¹ has been designed and synthesized by using L-valine methyl ester hydrochloride as the raw material and ethoxy salicylic aldehyde as terminal group.Then,four kinds of chiral tetranuclear quadruple-stranded helicates complexes were self-assembled by lanthanide ions and the chiral ligand H₂L¹.Through the preparation of crystals and analysis based on X-ray single crystal diffraction,the structures of these multinuclear lanthanide complexes were focused on.The result indicated that the ligand chirality was transferred and amplified to a higher level through self-assembly with lanthanide ions.Compared with the previous work in the laboratory,the reasons for the change of the ligand H₂L¹ during the self-assembly process were analyzed,which provided experimental reference for the design and construction of chiral multinuclear lanthanide complexes in the future.Chapter 3:We selected the tetranuclear quadruple-stranded helicates lanthanide complex self-assembled by lanthanide ion(Gd³⁺)and the chiral ligand H₂L¹ to investigate its catalytic property for epoxide cycloaddition.By exploring the optimal reaction conditions in terms of temperature,pressure,amount of catalyst and type of co-catalyst,various factors affecting the catalytic conversion rate were studied.Under the optimal reaction conditions,it was found that this lanthanide complex catalyst systems have the characteristics of low dosage?0.005 mol%?,wide application range of catalytic substrates,and high catalytic efficiency(TOF=4700h^-1).The feasible catalytic mechanism was also discussed.Chapter 4:We selected the tetranuclear tetra-helix lanthanide complex self-assembled by lanthanide ion(Nd³⁺)and the chiral ligand to investigate its chiral recognition for bio-related small molecules.The red-shifted and peak-enhanced ultraviolet signal,the weakened near-infrared luminescence signal and the transition of the circular dichroism spectrum signal proved that the complex can specifically recognize L-tartaric acid from various detection materials.It is the first application of chiral multinuclear lanthanide complexes in the recognition of L-tartaric acid,which is useful for the design and synthesis of effective chiral lanthanide complexes for the detection and identification of bio-related small molecules.Chapter 5:A flexible bridged acylhydrazone ligand H₂L² has been designed and synthesized by using disulfide group as functional linking group and ethoxy salicylic aldehyde as terminal group.And then,a binuclear double-helical lanthanide complex was constructed by lanthanide ion(Yb³⁺)and the flexible bridged ligand H₂L².Through the analysis of the crystal structure of the lanthanide complex,the structure characteristics of the multinuclear lanthanide complex was studied.By culturing the complex and lysozyme in the presence of TCEP,a complex-protein composite near-infrared luminescent film can be formed.Initially explored the application of lanthanide complexes in the field of thin film materials.