Design And Synthesis Of Fluorescence Probes Based On Terpyridine And The Detection Research For Fe³⁺

BackgroundIron element is widespread in a variety of key proteins or enzymes,such as hemoglobin,nucleotide reductase,cytochrome peroxidase and oxidase,and plays an important physiological role in organisms.Lacking of Fe³⁺in the body will directly lead to hypoferric anemia,while excessive Fe³⁺will bring about pernicious anemia,heart disease,kidney failure,diabetes and other diseases.Therefore,the detection of Fe³⁺is particularly significant in life science.At present,atomic absorption spectrometry（AAS）,inductively coupled plasma-mass spectrometry（ICP-MS）and other detection methods have been widely used in clinical detection of Fe³⁺.However,these detection methods exhibited obvious disadvantages,such as expensive analytical instruments and complication in sample pretreatment.Meanwhile,the fluorescence probe has been widely concerned owing to its high selectivity,high sensitivity,fast analytical speed,simple instrument and convenient operation.Therefore,the detection of Fe³⁺by fluorescent probes has became a hot topic in recent years.ObjectiveSeven fluorescent molecular probes based on tribipyridine were constructed.Research the effect detection of the seven fluorescent probes on Fe³⁺with the method of in vitro detection,select the fluorescence probes that specifically recognizes of Fe³⁺and the fluorescence probes that can specifically identify Fe³⁺and Fe²⁺were screened.The water solubility and fluorescence emission ability of the probe were improved,by changing the structure of the probe and introducing new groups into the probe.Methods1.Seven kinds of fluorescence probes（A1,A2,A3,A4,A5,A6 and B1）were synthesized by the methods of organic synthesis,and their structures were characterized by NMR hydrogen spectrum and mass spectrometry.2.The recognition of common metal ions by seven kinds of probes was studied via fluorescence emission spectrometry and ultraviolet absorption spectrometry.The nonlinear least square curve fitting was used to calculate the binding constants of the fluorescent probes and Fe³⁺,and investigate the binding ability of the probe to Fe³⁺.3.By comparing the recognition ability of different structure probes for Fe³⁺,we deduced the reason of the influence of probe structure on binding performance.Results1.The seven fluorescent probes successfully synthesized had good recognition effect on Fe³⁺,which was rapid,and had a good ability to resist interference of other ions.2.The combination of fluorescent probe A1 with Fe³⁺and Fe²⁺produced color reaction,which provided a more convenient and direct detection method for Fe³⁺and Fe²⁺,and had strong practical value.3.Increasing fluorescent groups can improve the luminous ability of the probe.At the same time,it can also reduce the binding sites of the fluorescent probe and the types of ions identified.So we can transform the multi-ion identification probe into a specific identification probe.4.The Bis（2-pyridine methyl）amine（DPA）group was successfully introduced into the probe B1,compared with probe A1,the fluorescence emission capacity of probe B1was increased by 12.4 times as much as that of A1,and the water solubility was increased by 6.5 times as much as that of A1.Conclusion1.The recognition of Fe³⁺and Fe²⁺by molecular probe A1 achieved the effect of naked eye recognition,and the specific recognition of Fe³⁺by probe A6.2.The DPA group introduced into probe B1which improved the capacity fluorescence emission and the water-solubility of the probe,and the selectivity of the probe was not affected.