Synthesis And Fluorescence Properties Of Coordination Polymers Based On Heterocyclic Organic Ligands

Coordination polymers are constructed from metal ions/clusters and organic ligands with inherently high microporosity,large specific surface area and strong chemical modification characteristics.Coordination polymer have been extensively studied,owing to structural diversity in the areas of gas storage and separation,organic pollutants separation and absorption,catalysis,drug delivery,luminescence.In this paper,a series of new coordination polymers were prepared by solvothermal method using the heterocycle ligand as the main organic ligand,transition metals and lanthanide metals as the metal centers.The structures and fluorescence properties of the coordination polymers were characterized by X-ray single crystal diffraction,powder X-ray diffraction(PXRD),thermogravimetric analysis(TG),infrared spectroscopy(IR)and fluorescence spectrum.The complexes are promising fluorescence sensors for detecting and recognizing organic pollutant and metal ions.ions.1.The coordination polymer were synthesized from theophylline as the main ligandTwo coordination polymers(1-2)were synthesized by using zinc ions as the central atoms,theophylline as the main organic ligand and fumaric acid(H2FA)or terephthalic acid(PTA)as auxiliary ligand.The structures and fluorescence properties of the two coordination polymers(1-2)were studied.The complexes 1-2 exhibited excellent recognition abilities and fluorescence quenching for acetone and quenching constant of complexes 1-2 are 15.29M-1?3.05 M-1,respectively.2.The coordination polymer were synthesized from 2,5-furandicarboxylic acid as the ligandThree coordination polymers(3-5)were synthesized by using zinc ions and terbium ion as the central atoms and 2,5-furandicarboxylic acid,(H2FDA)as the organic ligand.The structures and fluorescence properties of the three coordination polymers(3-5)were studied.The complexes 3-4 exhibited excellent recognition abilities and fluorescence quenching for diiodomethane,quenching constant of complexes 3-4 are 43.78M-1?149.60 M-1,respectively.Detection limit of complexes 3-4 are 6.91?m?676.5?m,respectively.5 exhibited excellent recognition abilities and fluorescence quenching for iron ions(Fe3+?Fe2+)and quenching constant of complexes 5 is 1.63×104 M-1?3.76×104 M-1,respectively.3.The coordination polymer were synthesized from 3,3-bipyridine as the main ligandFive coordination polymers(6-10)were synthesized by using zinc ions as the central atoms and 3,3-bipyridine(bpy)as the main organic ligand,2,5-furandicarboxylic acid(H2FDA),isophthalic acid(IPA),and 2,5-thiophenedicarboxylic acid(OBA)as auxiliary ligand.The structures and fluorescence properties of the five coordination polymers(6-10)were studied.The complexes 6-8 exhibited excellent recognition abilities and fluorescence quenching for nitrobenzene(NB),quenching constant of complexes 6-8 are 744 M-1?827 M-1 and 141 M-1 respectively.9-10 exhibited excellent recognition abilities and fluorescence quenching for iron ions(Fe3+)and quenching constant of complexes 9-10 are 1.48×104 M-1?8.09×104 M-1,respectively.