Studies On Synthesis,Characterization And Fluorescence Properties Of The Complexes Of Rare Earth Elements With Open-chain Amide Ligands

It is well known that rare earth complexes have excellent optical, electrical and magnetic properties. In these complexes, the energy can be transmitted effectively from the organic ligands to the center lanthanide ions through the antenna effect. So, the design of the ligands' structure to obtain more effective transmission becomes the key in the field of luminescene. Recently lanthanide complexes with open-chain amide ligands have attracted much attention mainly because the ligands have the unusual molecular structures: flexible chain, changeable terminal group and high selectivity and coordination to lanthanide ions.In this dissertation, three series of open-chain amide ligands and their lanthanide complexes have been synthesized and characterized in details with elemental analyses, molar conductance, spectra (infrared, ¹HNMR, MS). The luminescence properties of the complexes have been investigated. The dissertation includes five aspects:1. A brief view of the research progress in a variety of luminescent materials of lanthanide complexes and the prospect of rare earth complexes' application in many fields.2. Synthesis and characterization of the ligand N,N'-(1,3-phenylene)dipicolinamide (Fig 1) and its rare earth complexes. The results indicated that the composition of the complexes is [REL(NO₃)₂]NO₃·H₂O (RE = La³⁺,Eu³⁺,Gd³⁺,Tb³⁺,). In these complexes, the europium complex exhibited characteristic fluorescence of europiumion.3. Synthesis and characterization of the ligand6-acetamido-N,N-diethylpicolinamide (Fig 2) and its rare earth complexes. The results indicated that the composition of the complexes is [REL₂(NO₃)₂] NO₃·H₂O (RE = La³⁺,Eu³⁺,Tb³⁺). In these complexes, the terbium complex exhibited characteristic fluorescence of terbium ion.4. Synthesis and characterization of the ligand 6-acetamidopicolinic acid (Fig 3) and its rare earth complexes. The results indicated that the composition of the complexes is REL₃·4H₂O (RE = La³⁺,Eu³⁺,Gd³⁺,Tb³⁺). In these complexes, the europium complex exhibited characteristic fluorescence of europium ion.5. Synthesis and characterization of the ligand N²,N⁶-bis(phenylcarbamoyl)pyridine-2,6-dicarboxamide(Fig 4).