Synthesis And Eexplore The Properties Of Fluorescence Probes Based On Fluorescence Resonance Energy Transfer

It is well known that heavy metals and transition metals,anions are widely present in our living environment,and which play an important role in human health.And many metal elements are essential to the human body,however the high concentration of metal elements will endanger the human nervous system on the human body caused irreversible damage,causing the body function of the weakened or lost,leading to disease.Compared with other detection methods,the fluorescence method has the advantages of high sensitivity,high selectivity,simple and quick,real-time insitu detection and visualization.Therefore,the use of fluorescent probe on the metal ions for rapid and easy detection has significant application.Based on the fluorescence resonance energy transfer?FRET?response mechanism have a variety of energy transfer modes due to the presence of multiple fluorescent donors and receptor pairs,which can form a variety of fluorescence emission peaks,which makes the FRET type fluorescent probe has the advantages of higher sensitivity and superior selectivity.FRET probe is accurate and easy to operate.It can meet the requirements of complex samples,and has good application for the detection of heavy metal ions,environmental testing and water quality monitoring and cell imaging.However,the FRET-based fluorophore-based fluorophores are reported to be of a single type and can not constitute multiple pairs of energy donors and receptors.The emission spectra are relatively simple,the spectra are easy to overlap,and the optical signal is poorly selective,fluorescent signal is not easy to distinguish.Therefore,the preparation of two or more fluorophores containing two or more fluorescent groups,based on the FRET mechanism combined with C=N double bond isomerization and rhodamine loop-closed loop mechanism to build a variety of fluorescence response mechanism,to achieve complex samples Multi-ion efficient,fast and accurate detection,to achieve rapid,low-cost analysis.In thesis paper,FRET-type fluorescent probe,especially Rhodamine B-based fluorophore FRET probe for literature review.The mechanism and advantages of fluorescence resonance energy transfer?FRET?fluorescent probe are described in detail,and the development and application of FRET fluorescent probe in recent years are discussed.Based on the literature review and comparison of the fluorescence probe,the three?2-aminoethyl?amine was designed as a flexible platform.On one of the flexible chains,a rhodamine B was first connected.On the basis of this,the benzothiazolaldehyde,4-chloro-7-nitrobenzofurazan?NBD-Cl?,4-morpholinyl-1,8-naphthalene and 2-hydroxy-1-naphthalene formaldehyde was attached to the other two flexible chains,and two kinds of fluorescence probes based on FRET mechanism were synthesized.One is the three?2-aminoethyl?amine flexible platform to connect two different fluorescent groups of probes 1?4?6;the other is the three?2-aminoethyl?amine flexible platform connected to three different fluorescent groups of probes 2?3?5?7.The products and intermediates were characterized by ¹HNMR,¹³C-NMR,ESI-MS and IR.The results showed that the composites were consistent with the characterization.The sensitivities of metal ions and anions were investigated by fluorescence,UVVis absorption spectroscopy,IR,NMR,and MS.The mechanism of identification and interaction of metal ions and anions were investigated.Probe 2 is a superior multi-target recognition probe.The probe 2 clears the Hg²⁺ and Fe³⁺ ions by time resolution.The Hg²⁺ ions are added immediately to open the ring of the rhodamine ring of the probe,and the energy is transferred from the 8-formyl-7-hydroxycoumarin and the NBD unit to the rhodamine B,Fe³⁺ ions were added for 1 h before the FRET process occurred.At the same time to achieve the Hg²⁺,Fe³⁺ naked eye detection.In addition,probe 2 selectively identified Cu²⁺ through different excitation wavelengths,Cu²⁺ reacts with the NBD unit,allowing the probe to respond to enhanced fluorescence enhancement of Cu²⁺.At the same time,Probe 2 also selectively recognizes F-ions,the addition of F-ions makes the fluorescence of the probe significantly enhanced.The probe 6 can identify the different ions by solvent identification.In 1,4-dioxane/water?v/v,6/4?solvent,probe 6 can recognize Zn²⁺ selectively,while in CH₃CN/water?v/v,98/2?solvent,recognize Al3+ selectively through the FRET mechanism.At the same time to achieve the Al³⁺ naked eye detection.Probe 7 is a dual target,highly selective ratio of fluorescent probes.probe 7 selectively identified Hg²⁺ and Cu²⁺ through different excitation wavelengths.The probe 7 can selectively recognize Hg²⁺ through the FRET mechanism and also achieve naked eye recognition of Hg²⁺.Cu²⁺ ions are combined with the NBD unit of probe 7 to enhance the fluorescence of the probe body to realize the selective identification of Cu²⁺.