| Coordination polymers have received more and more attention due to their unique,novel and diverse structures,and they have also provided an opportunity for their wide application in the fields of magnetism,catalysis and fluorescence.Luminescent coordination polymer sensors have attracted more and more attention because of their high sensing performance,operability,easy synthesis of materials and low cost.Therefore,if efficient,sensitive,and stable functional coordination polymer fluorescent probe materials can be developed to achieve effective detection of heavy metal ions in aqueous solutions,it is of great significance for protecting a good environmental system and improving people's living standards.This paper selects two flexible carboxylic acid organic ligands with high symmetry,similar structure,and diverse coordination modes,thiodipropionic acid(H2TDPA)and glutaric acid(H2GTA),four nitrogen-containing imidazole auxiliary organic ligands tris[4-(imidazol-1yl)phenyl]amine(TPA),1,3,5-tris(1-imi dazolyl)benzene(TIB),4,4'-bis(imidazolyl)diphenyl ether(BDE)and 1,4-bis(1-i midazoly)benzene(BIB),respectively,with transition metal Zn2+and Cd2+ions,successfully prepared nine novel structure coordination polymerizations by solvo thermalor hydrothermal methods Material:[Cd(TDPA)(TIB)]n(1),{[Zn3(TDPA)3(TI B)2]·2(H2O)}n(2),{[Zn(TDPA)(TPA)]·(H2O)}n(3),{[Cd(TDPA)(TPA)]·(H2O)}n(4),{[Cd(TDPA)0.5(Cl)(TPA)]·(H2O)}n(5),{[Zn(TDPA)(BDE)]·(H2O)}n(6),{[Zn(GTA)(TIB)]·2(H2O)}n(7),{[Cd(GTA)(TIB)]·4(H2O)}n(8),{[Zn2(GTA)4(BIB)3]·2(H2O)}n(9).The structures of 9 coordination polymers were determined and characterized by CCD single crystal X-ray diffraction analysis,infrared spectroscopy(IR),thermogravimetric analysis(TGA),powder X-ray diffraction analysis(PXRD),fluorescence analysis and other methods.The structure determination and related characterization of polymer materials were carried out.Based on the full under standing and understanding of the basic structure and related characterization of complexes 1-9,the effects of a series of coordination polymer materials 1-9 as fluorescent probes for detecting anion and cation metal ions and organic solven ts were explored,and the detection mechanism was analyzed.The main research contents are as follows:(1)By solvothermal method or hydrothermal method,based on two organic carboxylic acid ligands,four nitrogen-containing ligands and corresponding Zn2+,Cd2+metal ion salts,nine new coordination polymer materials were successfully synthesized.The structure of the composition was determined and analyzed by CCD single crystal X-ray diffraction.The structure showed that the selected organic carboxylic acid ligands can be coordinated in different coordination modes,making the structure of coordination polymers 1-9 novel and diverse.(2)Through PXRD,IR,TGA and other methods,the synthesized 9 coordination polymer materials were characterized,and the purity and thermal stability of the 9synthetic materials were studied.The fluorescence test found that the complexes 1-5and 7-9 had excellent luminescence.Performance,inspired us to carry out application research on the fluorescent sensing performance of synthetic materials.(3)The synthetic materials 1-9 were used as fluorescent probes to detect the properties of Fe3+ions,Cr2O72-ions and nitrobenzene in aqueous solutions.The results found that synthetic materials 1-5 and 7-9 all have good selectivity and detection performance for Fe3+ions,Cr2O72-ions and nitrobenzene in aqueous solutions.(4)Aiming at the efficient detection of Fe3+ions,Cr2O72-ions and nitrobenzene in coordination polymers,the detection mechanism was explored and it was found that Fe3+ions,Cr2O72-ions and nitrobenzene were easier to absorb the excitation energy of coordination polymers,resulting It has a higher fluorescence quenching rate.That is,fluorescence quenching is caused by the competitive absorption of excitation energy between the coordination polymer and Fe3+ions,Cr2O72-ions,and nitrobenzene. |
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