Design And Synthesis Of Metal Ion Fluorescent Probes And Their Recognition Of Fe³⁺ And Cu²⁺

Objective:We designed and synthesized a novel fluorescent probe,characterized its structure and investigated its selective recognition on Fe³⁺and Cu²⁺,which can be applied for the selective recognition and detection on Fe³⁺and Cu²⁺in the water environment system.And this project can provide some basic experimental data for further development and application of these fluorescent probes.Methods:The ¹H NMR and ¹³C NMR were used to characterize the structure of fluorescent probe.And we used Fluorescence spectroscopy and NMR spectroscopy to investigate the interaction effect and anti-interference detection between pyrene-containing calix[3]arene fluorescent probe 1 and Fe³⁺,and the application range of p H and the detection of Fe³⁺in water samples（bottled drinking water,tap water and artificial lake）;And Fluorescence spectroscopy and NMR spectroscopy also been used to investigate the interaction effect and anti-interference detection between ruthenium-containing cup[4]arene fluorescent probe 2 and Fe³⁺,and the application range of p H and the detection of Fe³⁺in water samples（bottled drinking water,tap water and artificial lake）.Moreover,the Fluorescence spectrometry,UV-vis absorption spectroscopy and nuclear magnetic resonance spectroscopy were used to investigate the interaction effect and anti-interference detection between fluorescent probe TPE-An-Py based on a tetraphenylethylene-functionalized salicylaldehyde Schiff-base and Cu²⁺,and the application range of p H and the detection of Cu²⁺in water samples（bottled drinking water,tap water and artificial lake）.Results:1.We synthesized three fluorescent probes,including pyrene-containing calix[3]arene fluorescent probe 1,ruthenium-containing cup[4]arene fluorescent probe 2 and fluorescent probe TPE-An-Py based on a tetraphenylethylene-functionalized salicylaldehyde Schiff-base.And Tetrahydrofuran/Water(V_{tetrahydrofuran}/V_water=7/3,2.00×10^-3mol/LTris-HCl buffer,p H=7.00)was used as the detection system,the results showed that a significant decrease in the fluorescence intensity of probe 1 at482 nm caused by Fe³⁺,while other metal ions and anions have almost no effect on the fluorescence spectrum of probe 1 and they have no significant change on the fluorescence intensity of probe 1 when detecting Fe³⁺.When the concentration of Fe³⁺was in the range of 4.00×10^-6～2.00×10^-4mol/L,the fluorescence intensity of probe1 is linearly related to the concentration of Fe³⁺,and the correlation coefficient R²was0.9947,the detection limit（LOD）was 2.09×10^-7mol/L,and the binding constant（Ka）between the two was 2.68×10²mol/L.And in the conditions of p H=2.00～11.00,Fe³⁺caused a decrease of fluorescence intensity of probe 1 at 482 nm,and the decrease amplitude is almost the same.In selected experimental conditions,probe 1can instantly detect Fe³⁺in aqueous solution,and the recovery rates of Fe³⁺in bottled drinking water,tap water and artificial lake were 99.75～102.51%,99.06～101.27%and 99.28～103.15%.2.In Tetrahydrofuran/Tris-HCl buffer solution,which with a volume ratio of 4:1(2.00×10^-3mol/L,p H=7.00),Fe³⁺caused the decrease of the fluorescence intensity of probe 2 at 418nm,while other metal cations and anions had no significant effect on the fluorescence intensity of probe 2 and had little effect on the fluorescence intensity of probe 2 when Fe³⁺was detected.When the concentration of Fe³⁺was in the range of 5.00×10^-6～5.00×10^-4mol/L,the fluorescence intensity of fluorescent probe 2 showed a good linear relationship with the concentration of Fe³⁺,which correlation coefficient R²=0.9956,the detection limit was 7.68×10^-7mol/L,and the binding constant（Ka）was 7.85×10²mol/L.In the p H range of2.00-11.00,probe 2 can still detect Fe³⁺effectively.And in selected experimental conditions,probe 2 can instantly detect Fe³⁺in aqueous solution,and the recovery rates of Fe³⁺in bottled drinking water,tap water and artificial lake were98.22～100.05%,87.71～105.62%,94.00～117.37%.3.In Tetrahydrofuran/Tris-HCl buffer solution,which with a volume ratio of 4:1(2.00×10^-3mol/L,p H=7.00),Cu²⁺led to a decrease in the fluorescence intensity of probe TPE-An-Py at 598 nm,and the increase of the absorption peak at 439 nm,while other metal cations and anions have little effect on the fluorescence spectrum of probe TPE-An-Py(except for Fe³⁺,which had a slight effect),and the fluorescence intensity of probe TPE-An-Py had no obvious change when detecting Cu²⁺.When 10 times the mount of Cu²⁺than probe was added,the fluorescence quenching rate could reach at 91.66%.And the binding ratio between probe TPE-An-Py and Cu²⁺was 1:2,Ka=3.34×10³mol/L.When the concentration of Cu²⁺ranged from 5.00×10^-6to 1.20×10^-4mol/L,the fluorescence intensity of probe TPE-An-Py was linearly correlated with the concentration of Cu²⁺,R²=0.9929,LOD=2.36×10^-7mol/L;When the p H value was 3.00～7.00,there is no significant change in the fluorescence intensity of probe TPE-An-Py when detecting Cu²⁺.However,when the p H value was 8.00～11.00,the fluorescence intensity of the system had a slight decrease and the amplitude is small.In selected experimental conditions,the recovery rates of Cu²⁺in bottled drinking water,tap water and artificial lake by probe TPE-An-Py are 99.92～101.77%,96.79～107.50%and106.72～111.19%.Conclusion:1.In THF/Tris-HCl buffer solution,which with a volume ratio of 7:3(2.00×10^-3mol/L,p H=7.00),probe 1 can instantly recognize Fe³⁺with a better anti-interference ability and a stronger specificity.In the range of Fe³⁺concentration from 4.00×10^-6to 2.00×10^-4mol/L,probe 1 can quantitatively detect the content of Fe³⁺,LOD=2.09×10^-7mol/L.And Fe³⁺can also be detected effectively at a wide p H range.And probe 1 can detect Fe³⁺in water samples,and the recovery rate is 99.06～103.15%.2.In Tetrahydrofuran/Tris-HCl buffer solution,which with a volume ratio of 4:1(2.00×10^-3mol/L,p H=7.00),probe 2 can instantly identify Fe³⁺with a better anti-interference ability and a stronger specificity,and the detection limit for Fe³⁺is 7.68×10^-7mol/L.In different acid-base conditions,probe 2 can still recognize Fe³⁺;The recovery rate of Fe³⁺in water samples by probe 2 is87.71～117.37%.3.Using Tetrahydrofuran/Tris-HCl buffer solution(2.00×10^-3mol/L,p H=7.00),which with a volume ratio of 4:1 as the detection system,probe TPE-An-Py can selectively identify Cu²⁺with a strong specificity,and it can not easily affected by the genus ion and anion,thus has a strong anti-interference ability.When the concentration of Cu²⁺is between 5.00×10^-6and 1.20×10^-4mol/L,the probe TPE-An-Py can quantitatively detect Cu²⁺,LOD=2.36×10^-7mol/L.And probe TPE-An-Py and Cu²⁺can form a complex at molar ratio of 1:2.And in the p H condition of 8.00～11.00,the detection of Cu²⁺through probe TPE-An-Py is more sensitive and the recovery rate of Cu²⁺in water samples is 96.79～111.19%.