Isatin hydrazone-pyrazole Schiff base dual-response fluorescent probe and preparation method thereof

Abstract

The invention discloses a preparation method of a dual-response fluorescent probe based on an isatin hydrazone-pyrazole Schiff base structure, the dual-response fluorescent probe is synthesized by carrying out nucleophilic addition-elimination reaction on amino-functionalized isatin hydrazone and aldehyde group modified pyrazole, and the chemical structural formula of the dual-response fluorescent probe is as follows: # imgabs0 #. The probe disclosed by the invention has high specific recognition capability on Cu < 2 + > and CN <->. The probe shows fluorescence quenching response to Cu < 2 + >, the response time is short, and the anti-interference capability is strong. The probe realizes selective recognition of CN <-> in a fluorescence'opening 'mode, and shows a dual recognition signal of CN <-> along with obvious solution color change.

Description

Technical Field

[0001] The present invention belongs to the technical field of probe preparation, and particularly relates to an isatin hydrazone-pyrazole Schiff base dual-responsive fluorescent probe and a preparation method thereof. The probe prepared in this application shows high specific recognition ability for Cu 2+ and CN - . The probe shows a fluorescence quenching response to Cu 2+ , with a short response time and strong anti-interference ability; the probe realizes the selective recognition of CN - through a fluorescence "turn-on" method, accompanied by an obvious change in the solution color, showing dual recognition signals for CN - . Background Art

[0002] Ions are indispensable for all kinds of organisms and life forms, and play a crucial role in organisms and the environment. As an essential trace element in the human body, copper participates in a variety of metabolic processes in cells, including promoting enzyme catalysis, regulating the composition and function of proteins, driving DNA replication, and promoting cell differentiation. However, excessive intake may cause health problems such as low blood pressure and poisoning. Cyanide is an important chemical in industrial production and is widely used in fields such as gold mining, electroplating, pharmaceuticals, and organic synthesis. However, after untreated cyanide waste enters the environment, it is extremely easy to combine with organic and inorganic substances and spread through groundwater and surface water, causing serious ecological pollution. The toxicity mechanism of human cyanide poisoning mainly stems from the strong coordination ability between cyanide and metal ions, which can bind to the iron ions of cytochrome c-oxidase, resulting in the inactivation of metal enzymes, thereby inhibiting respiration and changing the normal activities of the respiratory and central nervous systems. Therefore, it is of great significance to develop a highly selective and sensitive Cu 2+ / CN - dual-responsive fluorescent probe.

[0003] Based on this, this application was developed. Summary of the Invention

[0004] The purpose of the present invention is to overcome the defects of the prior art and provide a novel isatin hydrazone-pyrazole Schiff base dual-responsive fluorescent probe, which is synthesized by a nucleophilic addition-elimination reaction of amino-functionalized isatin hydrazone and aldehyde-group-modified pyrazole. The probe shows high specific recognition ability for Cu 2+ and CN - .

[0005] The present invention also provides a preparation method and application of the above isatin hydrazone-pyrazole Schiff base dual-responsive fluorescent probe.

[0006] In order to achieve the above purpose, the solutions adopted in this application are as follows: An isatin-hydrazone-pyrazole Schiff base dual-responsive fluorescent probe, the structural formula of which is shown as follows: .

[0007] A preparation method of the above isatin-hydrazone-pyrazole Schiff base dual-responsive fluorescent probe, and its synthetic route is as follows: Specifically, it includes the following steps: 1) Dissolve isatin and hydrazine hydrate in absolute ethanol, heat and reflux at a constant temperature of 60 - 80 °C with stirring for 4 - 6 h. After the reaction is completed, cool to room temperature, concentrate the solvent, precipitate a solid, filter by suction, wash, dry, and recrystallize with absolute ethanol to obtain a bright yellow precipitate of isatin-3-hydrazone (Compound 1); 2) Dissolve phenylhydrazine and ethyl acetoacetate in the solvent methanol, heat and reflux at a constant temperature of 60 - 80 °C with stirring under the action of a catalyst hydrochloric acid for 2 - 4 h. After the reaction is completed, concentrate the solvent, adjust the pH to neutral, precipitate a solid, make a slurry with ethyl acetate, remove impurities, filter by suction, wash, dry, and obtain 5-methyl-2-phenyl-2,4-dihydro-3H-pyrazol-3-one (Compound 2); 3) React the 5-methyl-2-phenyl-2,4-dihydro-3H-pyrazol-3-one obtained in step 2), phosphorus oxychloride (POCl3) and N,N-dimethylformamide (DMF) at a constant temperature of 70 - 85 °C with stirring for 3 - 5 h. After the reaction is completed, pour it into ice water, precipitate a solid, filter by suction, wash, dry, and separate by column chromatography to obtain 5-chloro-3-methyl-1-phenyl-4,5-dihydro-1H-pyrazole-4-carbaldehyde (Compound 3); 4) Dissolve the isatin-3-hydrazone (Compound 1) obtained in step 1) and the 5-chloro-3-methyl-1-phenyl-4,5-dihydro-1H-pyrazole-4-carbaldehyde (Compound 3) obtained in step 3) in the solvent absolute ethanol, heat and reflux at a constant temperature of 75 - 80 °C with stirring under the action of a catalyst glacial acetic acid for 6 - 8 h. After the reaction is completed, cool to room temperature, precipitate a solid, filter by suction, wash, dry, and recrystallize with methanol to obtain the isatin-hydrazone-pyrazole Schiff base dual-responsive fluorescent probe IHS2.

[0008] Specifically, the molar ratio of isatin to hydrazine hydrate in step 1) is preferably 1∶1 - 2.

[0009] Further, the hydrazine hydrate in step 1) is preferably N2H4·H2O with a mass concentration of 80%; the hydrochloric acid in step 2) is preferably a HCl solution with a concentration of 0.7 - 0.9 mol·L -1 ; the molar ratio of ethyl acetoacetate to the catalyst hydrochloric acid in step 2) is preferably 1∶0.4 - 0.6.

[0010] Specifically, the molar ratio of phenylhydrazine to ethyl acetoacetate in step 2) is preferably 1:1 - 1.2.

[0011] Specifically, the molar ratio of 5-methyl-2-phenyl-2,4-dihydro-3H-pyrazol-3-one, phosphorus oxychloride (POCl3) and N,N-dimethylformamide (DMF) in step 3) is preferably 1:1.2 - 2:1.2 - 2.

[0012] Specifically, the molar ratio of isatin-3-hydrazone to 5-chloro-3-methyl-1-phenyl-4,5-dihydro-1H-pyrazole-4-carbaldehyde in step 4) is preferably 1:1 - 1.2; the molar ratio of 5-chloro-3-methyl-1-phenyl-4,5-dihydro-1H-pyrazole-4-carbaldehyde to the catalyst glacial acetic acid in step 4) is preferably 1:0.2 - 0.6.

[0013] Furthermore, the eluent used for column chromatography separation in step 3) is composed of a mixture of petroleum ether and ethyl acetate with a volume ratio of 4 - 6:1.

[0014] The present invention also provides the application of the above isatin hydrazone-pyrazole Schiff base dual-responsive fluorescent probe in specifically recognizing and detecting Cu 2+ and / or CN - therein.

[0015] Isatin is a natural indole derivative with significant pharmacological activities, showing broad-spectrum biological activities, including antibacterial, antimalarial, antitubercular, anticancer and antiviral properties. By modifying its C3, C5 and nitrogen atoms, the structural diversity and application scope of isatin derivatives have been expanded. Recent studies have shown that some novel isatin derivatives can be used as efficient chemical sensors to achieve selective recognition of specific anions. This indicates the development potential of the isatin skeleton in chemical sensors. Pyrazole compounds, due to their unique aromatic structure and N-donor properties, endow them with strong metal coordination ability, making them show unique advantages in ion recognition and detection, and are ideal choices for detecting various metal ions. In this application, a novel fluorescent probe IHS2 containing an imine structure is synthesized by the nucleophilic addition-elimination reaction of amino-functionalized isatin hydrazone and aldehyde-group-modified pyrazole. This probe shows high specific recognition ability for Cu 2+ / CN - exhibits high specific recognition ability.

[0016] The probe in this application shows high specific recognition ability for Cu 2+ and CN - exhibits high specific recognition ability. The probe shows a fluorescence quenching response to Cu 2+ with a short response time and strong anti-interference ability; the probe realizes the detection of CN through the fluorescence "turn-on" method -Selective recognition, accompanied by an obvious color change of the solution, showing dual recognition signals for CN - compared with the prior art, the advantages and beneficial effects of the present invention are as follows.

[0017] In the acetonitrile solvent of probe IHS2, the probe coordinates with Cu at a binding ratio of 2:1 through the oxygen atom of the isatin moiety (C=O) and the nitrogen atom of the Schiff base skeleton (C=N), achieving specific recognition of Cu

[0018] 2+ 2+ Specific recognition.

[0019] In the acetonitrile solvent of probe IHS2, the probe undergoes a deprotonation reaction with CN through two sites, -NH of the isatin moiety and -CH=N of the Schiff base moiety, achieving specific recognition of CN - - Specific recognition, resulting in a blue shift of the probe's spectrum and a change in the solution color. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 1H NMR spectrum of probe IHS2 of the present invention 1 H NMR); Figure 2 13C NMR spectrum of probe IHS2 of the present invention 13 C NMR); Figure 3 Fluorescence emission spectrum of probe IHS2 of the present invention for the selectivity of Cu 2+ (The abscissa is the wavelength, the ordinate is the fluorescence intensity, and the excitation wavelength is 304 nm); Figure 4 Fluorescence emission spectrum of probe IHS2 of the present invention for the selectivity of CN - (The abscissa is the wavelength, the ordinate is the fluorescence intensity, and the excitation wavelength is 304 nm).

[0021] Figure 5 Photographs of the solution color change of probe IHS2 of the present invention under natural light after adding different anions; Figure 6 Fluorescence emission spectrum of probe IHS2 (2.5×10 -5 mol∙L -1 ) of the present invention in CH3CN solution after adding different concentrations of Cu 2+ (The abscissa is the wavelength, the ordinate is the fluorescence intensity, and the excitation wavelength is 304 nm); Figure 7 Fluorescence emission spectrum of probe IHS2 (5×10 -5 mol·L -1 ) of the present invention in CH3CN solution after adding different concentrations of CN​​​- The fluorescence emission spectrum (the abscissa is the wavelength, the ordinate is the fluorescence intensity, and the excitation wavelength is 304 nm). Detailed implementation mode The technical solutions of the present invention will be further introduced in detail below in conjunction with the embodiments, and the protection scope of the present invention is not limited thereto.

[0023] In the following embodiments, the raw materials used are all ordinary commercially available products that can be directly purchased.

[0024] Room temperature refers to 25 ± 5 °C.

[0025] Example 1 A preparation method of an isatin-hydrazone-pyrazole Schiff base dual-responsive fluorescent probe specifically includes the following steps: 1) Weigh 1.471 g (10 mmol) of isatin in a 250 mL round-bottom flask, add 100 mL of anhydrous ethanol as the solvent, and slowly drip 1.001 g of an N2H4·H2O solution with a mass concentration of 80% (16 mmol) through a constant-pressure dropping funnel. Heat and reflux for 6 h under constant stirring at 78 °C. After the reaction is completed, cool to room temperature, concentrate part of the solvent, precipitate a solid, filter it by suction, wash it with anhydrous ethanol, dry it in vacuo at 60 °C for 12 h, and recrystallize it with anhydrous ethanol to obtain a bright yellow solid, which is isatin-3-hydrazone; 2) Weigh 8.111 g (75 mmol) of phenylhydrazine and 9.761 g (75 mmol) of ethyl acetoacetate in a 250 mL round-bottom flask, add 50 mL of methanol as the solvent, and 50 mL of a hydrochloric acid catalyst with a concentration of 0.8 mol·L -1 Heat and reflux for 2.5 h under constant stirring at 75 °C. After the reaction is completed, remove the organic solvent by rotary evaporation, adjust the pH of the reaction system to neutral with saturated NaOH solution, precipitate a solid, slurry it with ethyl acetate, filter it by suction, wash it with distilled water, and dry it in vacuo at 60 °C for 24 h to obtain a grayish-white solid, which is 5-methyl-2-phenyl-2,4-dihydro-3H-pyrazol-3-one; 3) Weigh 3.51 g (48 mmol) of DMF and add it to a 100 mL three-necked flask. Cool it to 0 - 5 °C in an ice-water bath, slowly add 7.36 g (48 mmol) of POCl3 dropwise using a constant-pressure dropping funnel, and stir for 1 h. Dissolve 6.97 g (40 mmol) of 5-methyl-2-phenyl-2,4-dihydro-3H-pyrazol-3-one in 15 mL of DMF, add it to the three-necked flask, and react under constant stirring at 85 °C for 4 h. After the reaction is completed, pour the reaction system into 100 mL of ice water, let it stand, and precipitate a brownish-yellow solid. Filter it by suction, wash it with distilled water, and dry it in vacuo at 60 °C for 24 h. Perform column chromatography separation using petroleum ether and ethyl acetate (v∶v = 5∶1) to obtain a pale-yellow solid, which is 5-chloro-3-methyl-1-phenyl-4,5-dihydro-1H-pyrazole-4-carbaldehyde; 4) Weigh 0.322 g (2 mmol) of isatin-3-hydrazone and 0.484 g (2.2 mmol) of 5-chloro-3-methyl-1-phenyl-4,5-dihydro-1H-pyrazole-4-carbaldehyde into a 100 mL round-bottom flask, add 40 mL of anhydrous ethanol solvent and 0.05 mL of glacial acetic acid catalyst, and heat under reflux with constant stirring at 80 °C for 8 h. After the reaction is completed, let the system stand and cool to room temperature, and a large amount of orange-yellow solid will precipitate. Filter it by suction, wash it with anhydrous ethanol, and dry it in vacuo at 60 °C for 12 h. Recrystallize it with methanol to obtain the target product, the dual-responsive fluorescent probe IHS2 of isatin hydrazone-pyrazole Schiff base.

[0026] The spectral data of the 1H NMR of the dual-responsive fluorescent probe IHS2 of the target product isatin hydrazone-pyrazole Schiff base is as follows. For details, see Figure 1 and Figure 2 : 1 1H NMR (400 MHz, DMSO- d 6 ) δ: 10.87 (s, 1H), 8.66 (s, 1H), 8.16 (d, J = 8.0 Hz, 1H), 7.66 - 7.55 (m, 5H), 7.41 (t, J = 8.0 Hz, 1H), 7.05 (t, J = 8.0 Hz, 1H), 6.91 (d, J = 4.0 Hz, 1H), 2.59 (s, 3H); 13 13C NMR (100 MHz, DMSO- d 6 ) δ:165.3, 156.4, 151.5, 150.7, 145.4, 137.4, 134.2, 130.6, 129.9, 129.7, 128.8, 125.7, 122.8, 117.0, 113.2, 111.3, 14.8; FT-IR (KBr cm -1 ) ν : 3429, 1737, 1616, 1554, 1331; HRMS ( m / z ): 364.0954 [M+H] + (calcd 364.0960)。

[0027] From the above spectral information, the structure of the target product indigo hydrazone-pyrazole Schiff base dual-responsive fluorescent probe IHS2 prepared can be deduced as follows: 。

[0028] The use of the probe IHS2 of the present invention.

[0029] Test Example 1 Take the indigo hydrazone-pyrazole Schiff base dual-responsive fluorescent probe IHS2 (0.0182 g, 0.05 mmol) prepared in Example 1, dissolve it in DMSO (10 mL), and prepare a probe mother liquor of 5×10 -3 mol·L -1 Take 0.5 mL of the 5×10 -3 mol·L -1 probe mother liquor, dilute it with CH3CN, and make up the volume to 100 mL in a volumetric flask to prepare a 2.5×10 -5 mol·L -1 probe solution. Dissolve different metal salts in 10 mL of deionized water to prepare a 1×10 -2 mol·L -1 metal ion stock solution. Use a microsyringe to take 5 μ L of the 1×10 -2 mol·L -1 metal ion stock solution into 2 mL of the 2.5×10 -5 mol·L -1 blank probe solution to prepare a probe solution containing different metal ions. Use an F7000 fluorescence spectrophotometer, with an excitation wavelength of 304 nm, to measure the blank probe solution and the addition of 1 equivalent of different interfering substances Li + 、Na + 、Mg 2+ 、Al 3+ 、K+ , Ca 2+ , Cr 3+ , Mn 2+ , Fe 3+ , Co 2+ , Ni 2+ , Cu 2+ , Zn 2 + , Cd 2+ , Hg 2+ , Ba 2+ , Pb 2+ (1 × 10 -2 mol·L -1 ) probe solution fluorescence emission spectra. The results are shown in Figure 3 . As Figure 3 shown, probe IHS2 obtained the maximum fluorescence emission peak at 407 nm; after adding Cu 2+ , the fluorescence emission peak decreased significantly and blue-shifted to 390 nm, while the emission peaks of the probe solutions added with other metal ions did not change significantly, indicating that probe IHS2 can specifically recognize Cu 2+ .

[0030] Test Example 2 Take the isatin hydrazone-pyrazole Schiff base dual-responsive fluorescent probe IHS2 (0.0182 g, 0.05 mmol) prepared in Example 1, dissolve it in DMSO (10 mL), and prepare a 5 × 10 -3 mol·L -1 probe mother liquor. Take 0.5 mL of the 5 × 10 -3 mol·L -1 probe mother liquor, dilute it with CH3CN, and make up to the mark in a 100 mL volumetric flask to prepare a 2.5 × 10 -5 mol·L -1 probe solution. Dissolve different salts in 10 mL of deionized water to prepare a 1 × 10 -2 mol·L -1 anion stock solution. Use a microsyringe to take 5 μ μL of the 1 × 10 - 2 mol·L -1 anion stock solution into 2 mL of the 2.5 × 10 -5 mol·L -1 blank probe solution to prepare probe solutions containing different anions. Use an F7000 fluorescence spectrophotometer, with 304 nm as the excitation wavelength, to measure the blank probe solution and the addition of 1 equivalent concentration of different interfering substances F - , Cl - , Br - , I -、HSO4 - 、NO3 - 、ClO4 - , CN - The fluorescence emission spectrum of the probe solution is shown in Figure 4 .like Figure 4 As shown in the fluorescence emission spectrum, it can be seen that the addition of other anions did not cause the change of the strongest fluorescence emission peak of IHS2 at 407nm; - After that, the fluorescence of the probe solution was significantly enhanced, and the fluorescence emission peak blue-shifted to 390.4 nm. The above experimental results show that IHS2 can effectively inhibit CN - Shows good specific recognition ability. Figure 5 The following are photos of the solution color changes of the probe IHS2 of the present invention after adding different anions under natural light. Figure 5 As shown, under natural light, the CH3CN solution of IHS2 was originally transparent and bright yellow. - After that, the solution turned colorless, indicating that IHS2 can achieve CN - of naked eye recognition.

[0031] Test Example 3 The isatin hydrazone-pyrazole Schiff base dual-responsive fluorescent probe IHS2 (0.0182 g 0.05 mmol) prepared in Example 1 was dissolved in DMSO (10 mL) and prepared into 5×10 -3 mol·L -1 Probe stock solution. Take 0.5 mL of 5×10 -3 mol·L -1 The probe stock solution was diluted with CH3CN and fixed to 2.5×10 -5 mol·L -1 Probe solution. Weigh CuCl2·2H2O (0.0170 g, 0.1 mmol) and dissolve it in deionized water (10 mL) to prepare 1×10 -2 mol·L -1 Cu 2+ In order to explore the interaction between probe IHS2 and Cu 2+ Fluorescence titration experiments were performed. -5 mol·L -1 1×10 -2 mol·L -1 Cu 2+ The stock solution was prepared by using a F7000 fluorescence spectrophotometer with an excitation wavelength of 304 nm to measure the changes in the fluorescence emission spectrum of the probe solution.

[0032] Figure 6 Figure 2 shows the fluorescence emission spectra of the probe IHS2 (2.5×10 -5 mol∙L -1 ) of the present invention in CH3CN solution with different concentrations of Cu 2+ (the abscissa is the wavelength, the ordinate is the fluorescence intensity, and the excitation wavelength is 304 nm). As Figure 6 shown, with the increase in the concentration of Cu 2+ (0 - 1.5 equivalents), the fluorescence intensity of IHS2 gradually decreases. When the concentration of Cu 2+ reaches 1.5 equivalents, the fluorescence intensity of the probe solution no longer changes, indicating that a concentration of 1.5 equivalents of Cu 2+ can achieve complete quenching of the fluorescence of IHS2.

[0033] Test Example 4 Take the isatin hydrazone-pyrazole Schiff base dual-responsive fluorescent probe IHS2 (0.0182 g, 0.05 mmol) prepared in Example 1, dissolve it in DMSO (10 mL), and prepare a probe mother liquor with a concentration of 5×10 -3 mol·L -1 ; Take 1 mL of the 5×10 -3 mol·L -1 probe mother liquor, dilute it with CH3CN, and make up to the mark in a 100 mL volumetric flask to prepare a probe solution with a concentration of 5×10 -5 mol·L -1 . Weigh (n-C4H9)4NCN (0.0268 g, 0.1 mmol) and dissolve it in deionized water (10 mL) to prepare a CN -2 mol·L -1 stock solution with a concentration of 1×10 - . In order to explore the relationship between the probe IHS2 and the concentration of CN - , a fluorescence titration experiment was carried out. Gradually add 1×10 -5 mol·L -1 of the CN -2 mol·L -1 stock solution to 2 mL of the 5×10 - probe solution, and use an F7000 fluorescence spectrophotometer to measure the change in the fluorescence emission spectrum of the probe solution with an excitation wavelength of 304 nm.

[0034] Figure 7 Figure 3 shows the fluorescence emission spectra of the probe IHS2 (5×10 -5 mol·L -1 ) of the present invention in CH3CN solution with different concentrations of CN - (the abscissa is the wavelength, the ordinate is the fluorescence intensity, and the excitation wavelength is 304 nm). As Figure 7As shown, with the increase of the concentration of CN - (0 - 1.7 equivalents), the fluorescence intensity of the system gradually increases and is accompanied by a blue shift of the emission peak; when the concentration of CN - reaches 1.7 equivalent concentration, the fluorescence intensity of the probe solution reaches the maximum.

Claims

1. An isatin hydrazone-pyrazole Schiff base dual-responsive fluorescent probe, characterized in that, The structural formula is as follows: 。 2. The preparation method of the isatin hydrazone-pyrazole Schiff base dual-responsive fluorescent probe according to claim 1, characterized in that, It includes the following steps: 1) Dissolve isatin and hydrazine hydrate in absolute ethanol, heat under reflux with constant stirring at 60 - 80 °C for 4 - 6 h. After the reaction is completed, cool to room temperature, concentrate the solvent, precipitate solids, filter by suction, wash, dry, and recrystallize to obtain isatin-3-ylhydrazone; 2) Dissolve phenylhydrazine and ethyl acetoacetate in methanol, heat under reflux with constant stirring at 60 - 80 °C for 2 - 4 h under the action of a catalyst hydrochloric acid. After the reaction is completed, concentrate the solvent, adjust the pH to neutral, precipitate solids, slurry with ethyl acetate, filter by suction, wash, dry to obtain 5-methyl-2-phenyl-2,4-dihydro-3H-pyrazol-3-one; 3) React 5-methyl-2-phenyl-2,4-dihydro-3H-pyrazol-3-one obtained in step 2), phosphorus oxychloride and N,N-dimethylformamide with constant stirring at 70 - 85 °C for 3 - 5 h. After the reaction is completed, pour into ice water, precipitate solids, filter by suction, wash, dry, and separate by column chromatography to obtain 5-chloro-3-methyl-1-phenyl-4,5-dihydro-1H-pyrazole-4-carbaldehyde; 4) Dissolve isatin-3-ylhydrazone obtained in step 1) and 5-chloro-3-methyl-1-phenyl-4,5-dihydro-1H-pyrazole-4-carbaldehyde obtained in step 3) in absolute ethanol, heat under reflux with constant stirring at 75 - 80 °C for 6 - 8 h under the action of a catalyst glacial acetic acid. After the reaction is completed, cool to room temperature, precipitate solids, filter by suction, wash, dry, and recrystallize to obtain the product.

3. The preparation method of the isatin hydrazone-pyrazole Schiff base dual-responsive fluorescent probe according to claim 2, wherein, The molar ratio of isatin to hydrazine hydrate in step 1) is 1∶1 - 2.

4. The preparation method of the isatin hydrazone-pyrazole Schiff base dual-responsive fluorescent probe according to claim 2, wherein The hydrazine hydrate described in step 1) is N2H4·H2O with a mass concentration of 80%; the hydrochloric acid described in step 2) is a HCl solution with a concentration of 0.7 - 0.9 mol·L -1 .

5. The preparation method of the isatin hydrazone-pyrazole Schiff base dual-responsive fluorescent probe according to claim 2, characterized in that, The molar ratio of phenylhydrazine to ethyl acetoacetate in step 2) is 1∶1 - 1.

2.

6. The preparation method of the isatin hydrazone-pyrazole Schiff base dual-responsive fluorescent probe according to claim 2, characterized in that, The molar ratio of 5-methyl-2-phenyl-2,4-dihydro-3H-pyrazol-3-one, phosphorus oxychloride and N,N-dimethylformamide in step 3) is 1∶1.2 - 2∶1.2 - 2.

7. The preparation method of the isatin hydrazone-pyrazole Schiff base dual-responsive fluorescent probe according to claim 2, characterized in that, The molar ratio of isatin-3-ylhydrazone to 5-chloro-3-methyl-1-phenyl-4,5-dihydro-1H-pyrazole-4-carbaldehyde in step 4) is 1∶1 - 1.

2.

8. The preparation method of the isatin hydrazone-pyrazole Schiff base dual-responsive fluorescent probe according to claim 2, characterized in that, The eluent used for column chromatography separation in step 3) is composed of a mixture of petroleum ether and ethyl acetate with a volume ratio of 4 - 6∶1.

9. Use of the isatin hydrazone-pyrazole Schiff base dual-responsive fluorescent probe according to claim 1 in specifically recognizing Cu 2+ and / or CN - therein.

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