Design,Synthesis And Luminescence Sensing Properties Of New Lanthanide Complexes

Due to the special luminescence properties of lanthanide complexes and the unique 4f electron of rare earth ions,they show large Stokes shift,long fluorescence lifetime and sharp emission peaks,which lead to their wide application in fluorescence sensing of detecting cations,anions,small organic molecules,temperature,and so on.In this thesis,three ligands were selected to construct five series of rare earth complexes.The precise structures and stabilities of these new complexes were determined by single crystal X-ray diffraction(SCXRD),Fourier infrared(FT-IR),X-ray powder diffraction(PXRD),thermogravimetric analysis(TGA),their luminescence,and performance as luminescence sensors were also studied.This paper mainly contains the following three parts:(1)Structure regulation for ultra-high luminescence quantum yield lanthanide complex and simultaneous detection of cancer marker and ferrous ionThis chapter uses 1,1,1-tris(hydroxymethyl)ethane(THME)as the ligand,and three series of rare earth complexes[Ln(CHO₂)₃]_n(Ln=Tb 1a,Eu 1b);[Ln(CHO₂)₄·(C₂H₈N)]_n(Ln=Y 1c,Gd 1d,Dy 1e);Ln(phen)₂(NO₃)₃(Ln=Tb 1f,Eu1g)were synthesized.The gadolinium break effect appears to be the reason for the different structures of 1a-1b and 1c-1e.In the subsequent synthesis process,auxiliary ligand of 1,10-phenanthroline(phen)was added to synthesize zero-dimensional lanthanide complexes 1f and 1g.The auxiliary ligand provides an antenna for efficient photons absorption,resulting in an ultra-high luminescence quantum yield(QY,90%)of europium complex(1g).The luminescence QY is among the highest record of monomeric(zero-dimensional)rare earth complexes.Furthermore,mononuclear Tb³⁺complex(1f)functionedas amultiplex sensor towards both Fe²⁺and cancer marker of 5-hydroxyindole-3-acetic acid(5-HIAA).Importantly,the limit of detection(LOD)for sensing 5-HIAA is an ultra-sensitive value of 1×10^-8M,which is even lower than that necessary for the early diagnosis of carcinoid tumors.More interestingly,sensing results in simulated urine reveals 1f has potential application for early diagnosis in the clinic.(2)Construction of new 60-nucleus clusters and application as temperature luminescence sensorIn this chapter,a series of lanthanide complexes Ln₆₀(Ln=Gd 2a,Tb 2b,Dy 2c,Ho 2d,Er 2e,Tm 2f,Yb 2g)with large nuclear number were successfully prepared by solvothermal method with 2,2-bis(hydroxymethyl)propionic acid(Hdmp)as the ligand.The structure,elements,and stability of the rare earth complexes were determined by SCXRD,FT-IR,PXRD,TGA and XPS.Moreover,the properties of luminescence and luminescence detection of 2b were studied,and the test results showed that the lanthanide complex 2b could be used as a luminescence sensor for temperature in wide range of 190-295 K.(3)A lanthanide complex based on 7-chloro-1-ethyl-6-fluoro-4-oxo-1,4-dihydroquinoline-3-carboxylic acid as a luminescence sensor for citric acidIn this chapter,a series of lanthanide complexes Ln(CFCA)₄(Ln=Eu 3a,Gd 3b,Tb 3c)were successfully prepared by solvothermal method with7-chloro-1-ethyl-6-fluoro-4-oxo-1,4-dihydroquinoline-3-carboxylic acid(CFCA)as the ligand.The elements,structure and stability of the rare earth complexes were determined by SCXRD,FT-IR,PXRD and TGA.Moreover,the luminescence properties and luminescence detection of 3a were studied,and the analysis of the test results showed that the lanthanide complex 3a could be used as a luminescence sensor for citric acid.