Synthesis And Properties Studies Of Naphthalimide Polymeric Fluorescent Probe

Metal is widely used in industrial production and plays an important role in industrial production.With the rapid development of industry,metal is also accompanied by various industrial processes and products into the environment.Excessive metal ions become common pollutants.Some metal elements,if accumulate in body,will seriously damage the health of human beings and various living organisms,their identification and detection is of important practical significance.Therefore,in order to protect the environment and human health,the development of rapid,direct and effective detection of metal ions is an urgent need to solve the important problem.At present,the metal ion detection methods include electrochemical method,cold atomic absorption spectrophotometry,high performance liquid chromatography,ion mass spectrometry and fluorescence chemical sensors and other methods,in which the fluorescence sensor stands out due to its high sensitivity,selectivity,response,real-time monitoring and low detection limits.Naphthalimide derivatives have been increasingly used as ion and small molecule fluorescence sensors in recent years.Since the 1,8-naphthalimide derivative fluorescent probe has the disadvantages of poor water solubility,ease of application,poor heat resistance,and their use,and the polymer membrane probe has a reusable,In the application,low cost of raw materials,environmental protection,production methods are simple,it is easy to achieve a large area display and more portable and so on.Therefore,the design of 1,8-naphthalimide as luminescent group,Schiff base as a recognition group,adjacent to the introduction of polymerization activity of allyl,the preparation of four polymer activity of fluorescent polymer monomer: 5-nitro-salicylaldehyde N-allyl-4-ethylenediamine-1,8-naphthalimide Schiff base（L1）,2,4-dihydroxybenzaldehyde Yl)-4-ethylenediamine-1,8-naphthalimide Schiff base（L2）;N-allyl-4-[3,3 ’-(（2-aminoethyl）(N ’-（2-hydroxybenzylidene）propane hydrazide]（L3）;N-allyl-4-[3,3’-(（2-aminoethyl）(N ’-（2-hydroxy-3-methoxybenzylidene）propane hydrazide]（L4）.The properties of the metal ions and their possible recognition mechanisms were studied.The synthesized naphthalimide small molecule fluorescent probes were copolymerized with styrene to synthesize naphthalimide polymer fluorescent probes and were prepared by using polymer materials.Four kinds of polymer membrane fluorescent probes were prepared by casting method.The paper included the following four parts:1: Introduction of the recent studies on ion fluorescent probes with 1,8-naphthalimide as fluorophore.2: Two monovalent naphthalimide derivatives,copper（II）ion fluorescent monomer probes,were designed and synthesized: L1 and L2.The photophysical properties and the recognition properties of the obtained molecular probes were studied.It was found that L1 showed high electivity to Cu2+ in DMSO / HEPES（1:1 v / v pH = 7.4）solution,while L2 was only in DMF / Tris-HCl（1:1 v / v pH = 7.2）solution good for Cu2+,and all of them showed obvious fluorescence quenching.When Cu2+ concentration is 0.5-5μM,both L1 and L2 have a good linear relationship with Cu2+,indicating that L1 and L2 can quantify Cu2+,and the calculated detection limits are 3.4 × 10-7 M and 1.92 × 10-7 M.The quenching constants of L1 and L2 are 3.4 × 104 M-1 and 1.95 × 105 M-1,respectively,which proves that Cu2+ leads to a large degree of fluorescence quenching of L1 and L2.The experimental results of Job plot,UV-Vis titration and fluorescence titration show that the binding patterns between L1 and L2 and Cu2+ are both 2:1 and fluorescence quenching can occur.Further application of L1 and L2 in the actual water sample Al³⁺ detection was carried out.By contrast,L1 and L2 can recognize Cu2+ in different solution systems,and L2 exhibits better recognition of Cu2+,and has a stronger binding ability to Cu2+.3: Two symmetric structures of bis-Schiff base naphthalimide-based fluorophore aluminum（III）ion probes L3 and L4 were designed and characterized by nuclear magnetic resonance spectroscopy,carbon spectroscopy,mass spectrometry and single crystal X-ray.The structure of the compound was obtained.The ability of the fluorescence probes L3 and L4 to recognize metal ions was investigated by fluorescence and UV spectroscopies.The experimental results show that in the ethanol / Tris-HCl buffer solution（1:1,v / v,pH = 7.2）,L3 can recognize Al³⁺,Al³⁺ in the DMF / HEPES（1:1 v / v pH = 7.4）buffer solution,which will cause the fluorescence intensity of the probes L3 and L4 to increase significantly and have good anti-interference to other metal ions.In the range of 2-10 μM and 3-11 μM,the enhancement of fluorescence intensity showed a good linear relationship with the concentration of Al³⁺ added.The chemimetric and binding modes of the probes L3 and L4 and Al³⁺ were studied by means of graph,UV-Vis titration,fluorescence titration and 1H NMR titration.It was found that both the probes L3 and L4 were able to recognize Al³⁺ and had a strong degree.The stoichiometry between L3 and L4 and Al³⁺ is 1:1,and the organic solvent has the smaller polarity,the stronger the fluorescence intensity and fluorescence quantum yield of L3 and L4,but the higher the fluorescence quantum yield of L3 and L4,and the L3 has a lower detection limit,and is further applied for the detection of Al³⁺ in the actual water sample,and the practical application of L3 and L4 is studied preliminarily.4: Four kinds of fluorescent luminescent materials were prepared by polymerizing four kinds of fluorescent monomer and styrene as raw materials,and then polymer electrolyte was prepared.The fluorescence properties and reusability of the fluorescent polymer materials inthe membrane state are investigated in detail.When the metal ions are in different concentration ranges,the fluorescence intensity of the membrane probe in the water environment satisfies a certain linear relationship with the metal ion concentration,the metal ions have better recognition and good reusability,the practical application of the membrane probe to do the bedding.