Synthesis And Fluorescence Properties Of Benzohydropyrones And Their Europium Complexes

Rare earth organic complexes have attracted widespread attention from researchers in the field of luminescent materials due to their unique fluorescent properties.Flavone compounds have excellent conjugated structures,but research on them has focused on the pharmaceutical field.?-diketone organic ligands can coordinate with rare earth ions in the form of chelation to obtain rare earth complexes with high fluorescence performance,which is a research hotspot in the field of rare earth complexes.In this thesis,a series of flavanone derivatives with?-diketone structure were synthesized based on the flavanone structure.Based on this,a ketone ligand with a tricarbonyl structure was synthesized.Several new?-diketones and triketone rare-earth complexes were prepared by coordinating them with rare-earth europium ions,respectively.The ligands and complexes were characterized by means of nuclear magnetic resonance,elemental analysis,infrared spectroscopy,fluorescence spectroscopy,and thermogravimetry,and the effect of the ligands on the properties of the complexes was explored.This has a great significance to further expand the research of rare earth organic complexes.The main research contents of the full text are as follows:?1?Four benzodihydropyranone compounds(L_1-4)were synthesized from 2'-hydroxyacetophenone as starting material,and four new binary rare earth complexes were obtained by reacting with the ion of rare earth europium.Elemental analysis and infrared spectroscopy were used to characterize the structure of the complexes,and its general structure can be speculated as Eu(L_1-4)₃·2H₂O.The fluorescence spectrum of the complexes were measured,and the fluorescence performance in the solid state were investigated.The results showed that all the four ligands could effectively sensitizes the rare earth europium ion to emit light,and the introduction of substituent had a great influence on the fluorescence properties.The rare earth complex Eu?L₄?₃·2H₂O with-Cl group showed the best fluorescence performance.The thermogravimetric analysis was showed that the different ligand substituents had little effect on the thermal stability of the complexes,and all the four rare earth complexes had good thermal stability.?2?Four benzodihydropyranone compounds(L_1-4)were synthesized from 2'-hydroxyacetophenone as starting material,and1,10-o-phenanthroline?phen?was introduced as the second ligand,and four new ternary rare earth complexes were obtained by reacting with the ion of rare earth europium.Elemental analysis and infrared spectroscopy were used to characterize the structure of the complexes,and its general structure can be speculated as Eu(L_1-4)₃·phen.The fluorescence spectrum of the complexes were measured to investigate the fluorescence performance in the solid state.The results showed that the introduction of the electron-donating group-CH₃,-OCH₃in the presence of the second ligand phen reduced the fluorescence intensity of the rare earth complexes,and the introduction of-Cl of the electron-withdrawing group effectively increased the fluorescence intensity of the rare earth complex.Among them,the complex Eu?L₄?₃·phen has the best fluorescence performance.The thermogravimetric analysis was showed the different ligand substituents had little effect on the thermal stability of the complexes,but the introduction of the second ligand phen improved the thermal stability of the rare earth complexes,and all the four rare earth complexes had good thermal stability.?3?A benzodihydropyranone ester?V₁?and a new triketone ligand?V₂?with a tricarbonyl group were synthesized from2'-hydroxyacetophenone as starting material,introducing phen as the second ligand,respectively reacted with rare earth europium ions to obtain two new ternary rare earth complexes.Elemental analysis and infrared spectroscopy were used to characterize the structure of the complexes,and its general structure can be speculated as Eu?V₁?₃·phen and Na[Eu?V₂?₂·phen].The solid fluorescence spectra of the complexes were measured,and the results showed that both ligands could sensitize the rare earth europium ions to emit light,but the fluorescence intensity of the complexes was relatively weak,which was mainly related to the structure and coordination mode of the ligands.