The Design,Synthesis And Ion Recognition Of Benzopyranone Derivatives Receptors

Anions and metal cations were widespread in real word and played a very important role in the fields of chemistry,medicine,and environment,etc.Thus the design and synthesis of artificial receptors with specific ion selective identification had attracted the significant attention of researchers.In recent years,benzopyranone derivatives had been served as fluorescent indicators,fluorescent probes and nonlinear optical materials because of their large stokes shift,high quantum yield and good photochemical properties.In this paper,three novel benzopyrone fluorescent receptors were constructed,and they were analyzed by UV-Vis absorption spectroscopy,fluorescence emission spectroscopy and 1H NMR.The main research contents are as follows:1.A series of benzopyrone fluorescent receptors were synthesized and characterized by IR,1H NMR,13C NMR,MS,HRMS and elemental analysis.2.The selectivity of receptors 7a?7e to the anions were investigated by UV-Vis absorption spectroscopy and fluorescence spectroscopy,which exhibited the selective trend in the order of F->AcO->Cl->Br-?I-?HSO4-.1H NMR titration and Job's curve showed that receptors 7a-7e formed 1:2 complexes with anions by hydrogen bonding.The binding constant KA was between 107 and 109 M-2.The detection limit of receptor molecule 7a to F-and AcO-was calculated to be 0.28 and 0.11?M,which demonstrated the high sensitivity to F-and AcO-.3.The receptors 13a-13d based on ICT were designed and synthesized.UV-Vis absorption spectroscopy and fluorescence spectroscopy studies indicated that the receptors 13a and 13c had significant responses to F-and AcO-,the detection limit was calculated to be between 0.05 and 0.16 ?M.Job's curve indicated that the binding ratios of both receptors 13a and 13c to F-and AcO-were 1:2 and 1:1,respectively.1H NMR titration indicated that the interaction between receptors and anion was mainly based on the hydrogen bonds of(O-H)+…X-,which increased the charge density on the O atoms of hydroxyl and the degree of positive and negative charge separation.It also inhibited intramolecular charge transfer and resulted in red shift of the fluorescence spectra.4.The fluorescence spectra of the receptor 16 was investigated by fluorescence emission spectroscopy.The receptor 16 had high selectivity and sensitivity to Hg2+,which exhibited the selective trend in the order of Hg2+>>Mg2+>Mn2+>NH4+?Pb2+?Na+?Zn2+?Ni2+?Co2+.A 1:1 stoichiometry of the receptor 16 towards Hg2+was proposed based on the mass spectrometry,infrared spectroscopy and Benesi-Hildebrand plots.The binding constant Ka was 3.99×104 M-1 and the detection limit was calculated to be 0.018 ?M.The results of MTT assay indicated that the receptor molecule 16 had no harm to Hela cells.Cell imaging studies indicated that the cytoplasm around Hela cells showed strong fluorescence intensity without Hg2+,however,the fluorescence intensity was quenched after adding 50 ?g/mL Hg2+.In summary,the receptor molecule 16 had a specific selectivity to mercury ions in vivo...