Synthesis And Properties Of Rare Earth Complexes Of 2,6-bis [N-Substituted Carbamoyl] Pyridine

Pyridine ligands are widely used in medical,environmental,agricultural and other fields due to it is easy to synthesize,stable in properties and adjustable in structure.Therefore,it aroused the interest of researchers.In order to research and discuss with different 2,6-Bis[N-Substituted Carbamoyl]Pyridine ligand coordination effect of rare earth metal elements,in this paper,different substituted imidazole,amino alcohol and thiophenyl amines were introduced to modify the structural unit 2,6-Bis[N-substituted carbamoyl]Pyridine.Four new ligands were obtained by modification.Nineteen new rare earthcomplexes,2,6-Bis[N-substituted carbamoyl]Pyridine ligands coordinates with rare earth metal ions,were synthesized and their structures and properties were studied.The interaction of four 2,6-Bis[N-substituted carbamoyl]Pyridine ligands with rare earth metal ions and its recognition properties were investigated.This paper is divided into five chapters.Chapter one is a liter-ature revie w on the research status and progress in the context of this research.The seco nd chapter is based on the previous accumulation of us,synthesized four 2,6-B is[N-substituted carbamoyl]Pyridine ligands.Firstly,we preparation the inte-r mediate Pyridine-2,6-dicarboxylic acid by pyridine-2,6-dicarboxylic acid as raw materials,then introduced replace imidazole group,the amino alcohols and thi-ophene based amino compounds,respectively,to synthesis of 2,6-Bis[N-?1'-imi-dazolepropyl?carbamoyl]pyridine?L₁?,2,6-Bis[N-?2'-hydroxypropyl?carbamoyl]pyridine?L₂?,2,6-Bis[N-?1',1'-dimethyl-2'-hydroxy?car-bamoyl]pyridine?L₃?and 2,6-bis[N-?2'-thienylethy1?earbamoy1]pyridine?L₄?.The four ligands were characterized by elemental microanalysis,NMR,IR and UV.The third chapter,using conventional heating synthesis method or hydrothermal synthesis method,four 2,6-Bis[n-substituted formamide]Pyridine ligands were respectively coordinated with different rare earth metal salts to prepare 19new rare earth metal complexes(C₁^C₁₉).The structures of 19 target rare earthcomplexes were characterized by elemental analysis,IR,UV and molar ratio method,and the composition of the complexes was determined.The fluorescence properties and thermal stability of the complexes were also discussed by fluorescence spectrometry and thermogravimetric analysis.The fourth chapter,the interaction between four 2,6-Bis[N-substituted carbamoyl]Pyridine ligands and rare earth metal ions was investigated by ultraviolet spectroscopy,and the recognition performance of four target ligands on rare earth metal ions was preliminar-ily analyzed.The result showed that These four target ligands and 10 rare earth ions La³⁺,Ce³⁺,Nd³⁺,Sm³⁺,Eu³⁺,Gd³⁺,Tb³⁺,Er³⁺,Pr³⁺and Y³⁺have obvious ion recognition ability,and are not affected by some common metal ions,so they have good anti-interference ability.However,among the 10 rare earth metal ions tested,the four target ligands,2,6-Bis[N-substituted formamide]Pyridine molecules have not been found to show specific selective recognition ability for a certain rare earth metal ion.The fifth chapter is the summary of the whole research work and the prospect of the next step.