| Rare earth complexes with good optical properties,have been widely used in the fields of photoelectric display,light enhancement,optical fiber communication,optical sensitization and so on.Bonding type of rare earth polymer luminescent materials could increase the luminous intensity of rare earth ions,and improve the luminous efficiency,due to the strong ultraviolet absorption of organic ligand and the efficient energy transfer from ligand to rare earth ions.In addition,bonding type rare earth-polymer luminescent materials still show the advantage of large Stokes shift,so could be used as a luminescent material and is widely used in the fields of photoelectric display,optical fiber communication,biology and new energy.Therefore,developing new bonding type rare earth-polymer luminescent materials,and exploring its structural properties is becoming a research hotspot at home and abroad.In this study,the new macromolecular reactions were adopted,and three kinds of N,N-bidentate ligands-functionalized polysulfone were prepared.Then,the functionalized polysulfone as macromolecular ligand,was used to coordinate with rare earth ions(Tb(Ⅲ)and Eu(Ⅲ)ions),and N,N-bidentate ligands-functionalized polysulfone-rare earth complexes were obtained finally.The structure of preparaed macromolecular ligands were characterized,and the photophysical and chemical properties of N,N-bidentate ligands-functionalized polysulfone-rare earth complexes were studied.Firstly,chloromethylation polysulfone(CMPSF)was prepared through chloromethylation reaction.Then,benzaldehyde(BA)was bonded onto polysulfone by means of the nucleophilic substitution reaction between CMPSF and hydroxy benzaldehyde,so as to get the benzaldehyde-modified polysulfone BA-PSF.Finally,the Schiff-base reaction occurred between polysulfone(PSF)bonded with hydroxybenzaldehyde(BA)and aminopyrazine(AP),leading to the aminopyrazine type bidentate Schiff base(APSB)ligand-functionalized PSF,APSB-PSF.The chemical structure of APSB-PSF was fully characterized by FTIR and ~1H-NMR spectra.The bonding amount of AP in the polysulfone side chain is determined to be about 1.51 mmol/g.Subsequently,APSB-PSF as macromolecular ligand and 1,10-phenanthroline(Phen)as small molecular and second ligand,were coordinated to Tb(Ⅲ)ion,obtaining the binary polymer-rare earth complex Tb(Ⅲ)-(APSB)3-PSF and ternary complex(Phen)1-Tb(Ⅲ)-(APSB)3-PSF respectively.The fluorescence-emission properties and luminescence mechanism of these complexes were studied.The experimental results show that the ligand APSB-PSF shows strong UV absorption because of a large π conjugated system in the structure of the bonded ligand APSB,and further it emits strong fluorescence by itself.However,after was coordinated to Tb(Ⅲ)ion,the absorption intensity of APSB-PSF is essentially the same,but its fluorescence emission is reduced greatly,that is,intramolecularly energy transfer occurred;at the same time,the complex Tb(Ⅲ)-(APSB)3-PSF emits stronger characteristic fluorescence of Tb(Ⅲ)ion than TbCl3,due to accepting the transferred energy from APSB-PSF,namely the sensitization effect of APSB-PSF on the luminescence of Tb(III)ions was occurred.The triplet state energy of the bonded ligand APSB is not matched with the resonant energy level of Eu(Ⅲ)ion,resulting in that the fluorescence emission of the complex Eu(Ⅲ)-(APSB)3-PSF has not been improved.fluorescence emission.In addition,the ternary complex(Phen)1-Tb(Ⅲ)-(APSB)3-PSF also emits the characteristic fluorescence of Tb(Ⅲ)ion,and its fluorescence emission intensity is higher than that of the binary complex Tb(Ⅲ)-(APSB)3-PSF.And the thermal stability rare earth complexes is outstanding,its apparent weightlessness temperature is 280℃.secondly,phenanthroline(Phen)thtough two step reaction of nitration and amination,so as to get the amino phenanthroline.Finally,the Schiff-base reaction occurred between the modified polysulfone(BA-PSF)with amino phenanthroline,leading to the functionalization of side chain containing(Phen)ligands polysulfone Phen-PSF(I).The chemical structure was characterized by ~1H-NMR,infrared spectroscopy(FT-IR).The bonding amount of Phen in the polysulfone side chain is determined to be about 1.22 mmol/g by elemental analysis(EA).Subsequently,Phen-PSF(I)as macromolecular ligand,was coordinated to Eu(Ⅲ)ion,obtaining the binary polymer-rare earth complex Eu(Ⅲ)-(Phen)3-PSF(I)The fluorescence-emission properties and luminescence mechanism of these complexes were studied.At the same time,change the functional polysulfone Phen-PSF(I)and the dosage of the Eu(Ⅲ)rare earth ions,test the fluorescence intensity after coordination,thoroughly discusses the energy transfer mechanism between them.The experimental results show that the macromolecular ligand Phen-PSF(I)can not only strongly absorb ultraviolet light,and further it emits strong fluorescence by itself;However,after was coordinated to Eu(Ⅲ)ion,the absorption intensity of Phen-PSF(I)is essentially the same,but its fluorescence emission is reduced greatly,that is,intramolecularly energy transfer occurred.At the same time,the complex Eu(Ⅲ)-(Phen)3-PSF(I)emits stronger characteristic fluorescence of Eu(Ⅲ)ion than EuCl3,due to accepting the transferred energy from Phen-PSF(I),namely the sensitization effect of Phen-PSF(I)on the luminescence of Eu(III)ions was occurred.In addition,the proportion of the ligand Phen-PSF(I)too large can also cause complexes characteristic fluorescence of Eu(Ⅲ)is quenching.The triplet state energy of the Phen-PSF(I)is not matched with the resonant energy level of Tb(Ⅲ)ion,resulting in that the fluorescence emission of the complex almost not emit fluorescence.And the thermal stability rare earth complexes is outstanding,its apparent weightlessness temperature is 278℃.Finally,the nucleophilic substitution reaction between chloromethylated polysulfone(CMPSF)and 4,7-two hydroxy-1,10-phenanthroline(H-Phen),leading to the side chain bonded with 4,7-two hydroxy-1,10-phenanthroline groups functionalized polysulfone Phen-PSF(II).The chemical structure was characterized by ~1H-NMR and infrared spectroscopy(FT-IR).Subsequently,Phen-PSF(II)as macromolecular ligand and 1,10-phenanthroline(Phen)as small molecular and second ligand,were coordinated to Eu(Ⅲ)ion,obtaining the binary polymer-rare earth complex Eu(Ⅲ)-(Phen)3-PSF(II)and ternary complex(Phen)1-PSF(II)-(Phen)3-Eu(Ⅲ)respectively.The fluorescence-emission properties and luminescence mechanism of these complexes were studied.The experimental results show that this two complexs can emit stronger characteristic fluorescence of Eu(Ⅲ)ion than EuCl3.In addition,the ternary complex(Phen)1-PSF(II)-(Phen)3-Eu(Ⅲ)fluorescence emission intensity is higher than that of the binary complex Eu(Ⅲ)-(Phen)3-PSF(II).And the thermal stability rare earth complexes is outstanding,its apparent weightlessness temperature is 300℃. |
