The Self-assembly Of Lanthanide Complexes Based On Acylhydrazone And Schiff Base Ligands And Their Functional Properties Of NIR Luminescence

Schiff base ligands have been applied to build lanthanide supramolecular complexes with novel structures and different functions due to their various structures,coordination sites and coordination modes.Recently,more researches are related to the near-infrared luminescence of lanthanide complexes because of the unique photophysical properties as well as the advantages including high intensity,narrow line width,long lifetime,minimal background,and strong penetrating ability.Studies based on the near-infrared luminescence properties of lanthanides has been successfully utilized in many fields,such as fluorescence immunoassays,time-resolved microanalysis,and laser signal amplification.In this thesis,six types of Schiff base ligands with acylhydrazone were designed and synthesized to investigate the differences of their self-assembly processes with lanthanide ions.The structures of some products were adjusted to construct single core,double-core,and hexa-core lanthanide supramolecular complexes.Also,based on a series of lanthanide complexes which was designed by this research group,the ion recognition function of these complexes was investigated.The current thesis includes four aspects:1.The background of supramolecular chemistry based on host-guest and self-assembly chemistry is reviewed,as well as the synthesis,classification and application of Schiff base and acylhydrazone ligands.Meanwhile,the recent research progresses of the near-infrared luminescence of lanthanide complexes are summarized.2.A acylhydrazone chain-like ligand was designed and synthesized using 8-hydroxyquinoline derivatives as antennas by our research group,and the structures and the near infrared luminescence properties of these complexes were characterized.Based on those studies,the structure of Nd³⁺complex has been further clarified,and the space structure of coordination atoms in the cavity of these lanthanide complexes has been investigated.It was explored whether the cavity inside of these complexes is suitable for coordination with uranyl ions to achieve the recognition function of uranyl ions.The cations recognition of these complexes was studied using UV and NIR spectroscopy,and the specific recognition for uranyl ions was revealed and verified.The mechanism of such recognition was also discussed.In general,this research is significant for near-infrared luminescence studies of lanthanide complexes and the detection for uranyl ions.3.Four ligands based on 2-aminonicotinoyl hydrazide were designed and synthesis,as well as six double-core and hexa-core lanthanide complexes by self-assembly between these ligands with lanthanide ions(Er³⁺,Yb³⁺).The structures of these complexes were studied by using infrared,XRD powder diffraction,and X-ray single crystal diffraction.Furthermore,the solid near-infrared luminescence properties of lanthanide complexes were characterized and discussed,which indicates that the sensitization of these ligands to lanthanides ion near-infrared luminescence are based on energy transfer.4.A tridentate Schiff base ligand and a double Schiff base ligand were synthesized.The inducing effects of the anion and cation on the structure of the complex during the self-assembly process with lanthanide ions were studied.Six lanthanide(Eu³⁺,Dy³⁺,Er³⁺,Yb³⁺)single and double-core complexes,one 3d-4f heteronuclear tetra-core complex based on Zn²⁺and Tb³⁺were generated.Structures of these seven complexes were characterized by infrared,XRD powder diffraction and X-ray single crystal diffraction.The solid near-infrared luminescence properties of the first six complexes were characterized and their future applications were discussed.