A molecular fluorescent probe for detecting Hg 2+ and a preparation method and application thereof

Abstract

The application discloses a molecular fluorescent probe for detecting Hg 2+ , and a preparation method and application thereof, and has a structural formula: the preparation method comprises the following steps: firstly, reacting phenoxazine with 1-bromoethane to obtain compound A; then, generating compound B under the action of DMF and POCl3; and finally, reacting with 1,3-indane diketone to obtain the molecular fluorescent probe. The molecular fluorescent probe has the advantages of simple structure, convenient synthesis, easily obtained raw materials, low cost, high selectivity and high sensitivity, and has important practical application values for detecting samples containing Hg 2+ in the environment.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of organic synthesis and analytical chemistry, and more particularly to a molecular fluorescent probe for detecting Hg 2+ and a preparation method and application thereof. BACKGROUND

[0002] Mercury is the only liquid metal at room temperature, and it is one of the most toxic heavy metal pollutants due to its flowability. It widely exists in water, air and soil. At present, there are about 80 kinds of industries in the world that need mercury as raw material or auxiliary material, and the mercury discharged into the environment is estimated to be 5000 tons per year. The mercury in the environment can enter the biological body through the food chain and accumulate, causing damage to the respiratory system and central nervous system of the human body, causing cerebral palsy, mental retardation, and even threatening the liver and kidney, and seriously harming human health.

[0003] Due to the increasing harm of mercury ions to the environment and human health, researchers have developed and widely applied many mercury ion detection methods such as electrochemical method, atomic emission spectrometry, spectrophotometry, inductively coupled plasma mass spectrometry, atomic absorption spectrometry and gas chromatography. Due to the characteristics of simultaneous detection of multiple elements and rapid analysis, these conventional detection technologies are increasingly widely used in various fields. However, these methods still have many shortcomings, such as the need for expensive experimental instruments, harsh sample pretreatment conditions, high requirements for testers, complex instrument structure and inability to perform real-time monitoring. In order to protect the environment and maintain ecological balance, it is urgent to develop a simple, rapid and highly sensitive method for detecting mercury ions.

[0004] The fluorescent probe method has the characteristics of high sensitivity, high selectivity, simple and fast operation, and is increasingly valued by people and gradually becoming a research hotspot in the field of rapid detection technology. At present, a variety of fluorescent probes for detecting mercury ions have been reported. Kumar's research group developed a highly selective and sensitive chemical sensor for colorimetric and fluorescent dual detection of Hg 2+ (Journal of Photochemistry and Photobiology A: Chemistry, 2023, 434:114220), and Shen's research group designed and synthesized a kind of fluorescent probe for Hg 2+A novel naphthalimide-based fluorescent probe was designed and synthesized by using 1,2-dithiaalkyl as the recognition group (Acs Omega, 2020, 5(29): 18176-18184). Although many excellent optical probes have been developed for the detection of Hg 2+ , there are still some shortcomings such as complicated preparation process, not cheap and easy to obtain raw materials, slow response, poor selectivity, poor water solubility and detection limit.

[0005] Therefore, how to develop a simple, rapid and high-sensitivity fluorescent probe for detecting Hg 2+ is a problem that those skilled in the art need to solve. SUMMARY

[0006] In view of this, the purpose of the present application is to provide a molecular fluorescent probe for detecting Hg 2+ and its preparation method and application, so as to solve the problems in the prior art.

[0007] In order to achieve the above purpose, the technical scheme adopted by the present application is as follows:

[0008] A molecular fluorescent probe for detecting Hg 2+ , the structural formula of which is:

[0009] A preparation method of the above-mentioned molecular fluorescent probe for detecting Hg 2+ , specifically comprising the following steps:

[0010] (1) At room temperature, phenoxazine, anhydrous DMSO (dimethyl sulfoxide) solution, sodium hydroxide and 1-bromoethane are mixed, stirred and reacted, after the reaction is completed, the reaction solution is quenched with water, and extracted with ethyl acetate, the organic phase is separated and dried with anhydrous MgSO4 (magnesium sulfate), the solvent is removed, and the residue is purified by column chromatography to obtain compound A;

[0011] The structural formula of compound A is:

[0012] (2) Under low temperature conditions, compound A, anhydrous DMF (N,N-dimethylformamide), POCl3 (phosphorus oxychloride) and anhydrous 1,2-dichloroethane are mixed and heated to reflux, after the reaction is completed, the reaction solution is quenched with 20% (mass fraction) NaOH (sodium hydroxide) solution, and extracted with water and dichloromethane, the organic phase is separated and dried with anhydrous MgSO4, the solvent is removed under vacuum, and the residue is purified by column chromatography to obtain compound B;

[0013] The structural formula of compound B is:

[0014] (3) mixing compound B, 1,3-indanedione, anhydrous ethanol and potassium methoxide, heating and reacting, monitoring the reaction by TLC until the raw material point disappears, cooling the mixture, precipitating, filtering, washing with anhydrous ethanol, drying with anhydrous MgSO4, and purifying by column chromatography to obtain a molecular fluorescent probe for detecting Hg 2+ .

[0015] The synthesis route of the molecular fluorescent probe of the present application is as follows:

[0016]

[0017] Further, in the above step (1), the ratio of the amounts of phenoxazine, anhydrous DMSO solution, sodium hydroxide and 1-bromoethane is 0.01 mol: 30 mL: 0.05 mol: 0.02 mol.

[0018] Further, in the above step (1), the stirring reaction time is 12-24 h, preferably 18 h.

[0019] Further, in the above step (1), the eluent used in the column chromatography is ethyl acetate: petroleum ether = 1:5.

[0020] Further, in the above step (2), the ratio of the amounts of compound A, anhydrous DMF, POCl3 and anhydrous 1,2-dichloroethane is 5.5 mmol: 3 mL: 5 mL: 25 mL.

[0021] Further, in the above step (2), the low temperature condition is (-20)-0℃, preferably -10℃; the heating and refluxing reaction temperature is 50-150℃, preferably 100℃; and the heating and refluxing reaction time is 12-36 h, preferably 24 h.

[0022] Further, in the above step (2), the eluent used in the column chromatography is ethyl acetate: dichloromethane = 1:10 (volume ratio).

[0023] Further, in the above step (3), the ratio of the amounts of compound B, 1,3-indanedione, anhydrous ethanol and potassium methoxide is 4.2 mmol: 5 mmol: 20 mL: 0.06 mmol.

[0024] Further, in the above step (3), the heating reaction temperature is 50-120℃, preferably 90℃; and the heating reaction time is 4-12 h, preferably 8 h.

[0025] Furthermore, in step (3) above, the developing solvent for TLC monitoring is dichloromethane: petroleum ether = 1:1 (volume ratio).

[0026] Furthermore, in step (3) above, the eluent used in column chromatography is dichloromethane: petroleum ether = 1:2 (volume ratio).

[0027] This invention also claims protection for a molecular fluorescent probe described above or prepared by the above method for detecting Hg. 2+ Applications in [the context of the text].

[0028] As can be seen from the above technical solution, compared with the prior art, the beneficial effects of the present invention are as follows:

[0029] 1. The ethylphenoxazine in this invention uses its electron-rich structure as an electron donor, and also possesses a fluorescent group with a rigid planar conjugated large π-bond system, with 1,3-indanedione as the acceptor, Hg 2+ This invention can cause changes in the structure of the molecular fluorescent probe, which can then be detected by the instrument.

[0030] 2. The molecular fluorescent probe of this invention has the advantages of simple structure, convenient synthesis, readily available raw materials, low cost, strong selectivity, and high sensitivity, and is effective against Hg-containing substances in the environment. 2+ The sample testing has important practical application value. Attached Figure Description

[0031] Figure 1 The compound A obtained in step (1) of Example 2 1 H NMR spectrum (CDCl3, 500MHz);

[0032] Figure 2 The compound A obtained in step (1) of Example 2 13 C NMR spectrum (CDCl3, 125MHz);

[0033] Figure 3 The compound B obtained in step (2) of Example 2 1 H NMR spectrum (CDCl3, 500MHz);

[0034] Figure 4 The compound B obtained in step (2) of Example 2 13 C NMR spectrum (CDCl3, 125MHz);

[0035] Figure 5 The molecular fluorescent probe prepared in step (3) of Example 2 1 H NMR spectrum (CDCl3, 500MHz);

[0036] Figure 6 The fluorescence spectrum of the molecular fluorescent probe prepared in step (3) of Example 2 in the presence of different metal ions. 13 C NMR spectrum (CDC13, 125 MHz);

[0037] Figure 7 The fluorescence spectrum of the molecular fluorescent probe prepared in step (3) of Example 2 in the presence of different metal ions. DETAILED DESCRIPTION

[0038] The technical solutions in the embodiments of the present application will be described clearly and completely below. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the present application.

[0039] Example 1

[0040] The molecular fluorescent probe for detecting Hg 2+ , and the structural formula is:

[0041] Example 2

[0042] The preparation method of the molecular fluorescent probe for detecting Hg 2+ in Example 1 specifically includes the following steps:

[0043] (1) At room temperature, a round-bottom flask is added with phenoxazine (1.83 g, 0.01 mol), anhydrous DMSO solution (30 mL) and sodium hydroxide solid (2 g, 0.05 mol), mixed, 1-bromoethane (1.49 mL, 0.02 mol) is added dropwise under the condition of nitrogen protection, and stirred for reaction for 18 h. After the reaction is completed, the reaction liquid is quenched with water, and extracted with ethyl acetate. The organic phase is separated and dried with anhydrous MgSO4. The solvent is removed, and the residue is purified by column chromatography. The eluent is ethyl acetate: petroleum ether = 1:5, to obtain compound A;

[0044] (2) Under the condition of low temperature of (-20)-0 ℃, a round-bottom flask is added with compound A (1.16 g, 5.5 mmol), anhydrous DMF (3 mL), POCl3(5 mL) and anhydrous 1,2-dichloroethane (25 mL), mixed, heated to 100 ℃ and refluxed for reaction for 24 h. After the reaction is completed, the reaction liquid is quenched with 20% NaOH solution, and extracted with water and dichloromethane. The organic phase is separated and dried with anhydrous MgSO4. The solvent is removed in vacuum, and the residue is purified by column chromatography. The eluent is ethyl acetate: dichloromethane = 1:10, to obtain compound B;

[0045] (3) To a round bottom flask was added compound B (1.00 g, 4.2 mmol), 1,3-indanedione (0.73 g, 5 mmol), absolute ethanol (20 mL) and potassium methoxide (4.21 mg, 0.06 mmol), mixed, heated to 90 °C for 8 h, the reaction was monitored by TLC until the starting material point disappeared, the developing agent was dichloromethane: petroleum ether = 1:1, the mixture was cooled, precipitated, filtered, washed with absolute ethanol, dried over anhydrous MgS04, purified by column chromatography, eluent dichloromethane: petroleum ether = 1:2, to obtain a molecular fluorescent probe for detecting Hg 2 + .

[0046] Example 3

[0047] Example 1, the preparation method of a molecular fluorescent probe for detecting Hg 2+ , specifically comprising the following steps:

[0048] (1) At room temperature, a round bottom flask was added with phenoxazine (1.83 g, 0.01 mol), anhydrous DMSO solution (30 mL) and sodium hydroxide solid (2 g, 0.05 mol), mixed, 1-bromoethane (1.49 mL, 0.02 mol) was added dropwise under the condition of nitrogen protection, stirred for 12 h, after the reaction was completed, the reaction solution was quenched with water and extracted with ethyl acetate, the organic phase was separated and dried over anhydrous MgS04, the solvent was removed, and the residue was purified by column chromatography, eluent ethyl acetate: petroleum ether = 1:5, to obtain compound A;

[0049] (2) Under the condition of low temperature at (-20)-0 °C, a round bottom flask was added with compound A (1.16 g, 5.5 mmol), anhydrous DMF (3 mL), POCl3 (5 mL) and anhydrous 1,2-dichloroethane (25 mL), mixed, heated to 50 °C for 36 h, after the reaction was completed, the reaction solution was quenched with 20% NaOH solution, and extracted with water and dichloromethane, the organic phase was separated and dried over anhydrous MgS04, the solvent was removed under vacuum, and the residue was purified by column chromatography, eluent ethyl acetate: dichloromethane = 1:10, to obtain compound B;

[0050] (3) To a round bottom flask was added compound B (1.00 g, 4.2 mmol), 1,3-indanedione (0.73 g, 5 mmol), absolute ethanol (20 mL) and potassium methoxide (4.21 mg, 0.06 mmol), mixed, heated to 50 °C for 12 h, the reaction was monitored by TLC until the starting material point disappeared, the developing agent was dichloromethane: petroleum ether = 1:1, the mixture was cooled, precipitated, filtered, washed with absolute ethanol, dried over anhydrous MgS04, purified by column chromatography, eluent dichloromethane: petroleum ether = 1:2, to obtain a molecular fluorescent probe for detecting Hg2 + molecular fluorescent probe for detecting Hg

[0051] Example 4

[0052] molecular fluorescent probe for detecting Hg 2+ The preparation method of the molecular fluorescent probe for detecting Hg

[0053] (1) At room temperature, a round-bottom flask was added with phenoxazine (1.83 g, 0.01 mol), anhydrous DMSO solution (30 mL) and sodium hydroxide solid (2 g, 0.05 mol), mixed, 1-bromoethane (1.49 mL, 0.02 mol) was added dropwise under the condition of nitrogen protection, stirred for 24 h, after the reaction was completed, the reaction liquid was quenched with water, and extracted with ethyl acetate, the organic phase was separated and dried with anhydrous MgSO4, the solvent was removed, and the residue was purified by column chromatography, eluent was ethyl acetate: petroleum ether = 1:5, to obtain compound A;

[0054] (2) Under the condition of low temperature at (-20)-0℃, a round-bottom flask was added with compound A (1.16 g, 5.5 mmol), anhydrous DMF (3 mL), (POCl3 5 mL) and anhydrous 1,2-dichloroethane (25 mL), mixed, heated to 150℃ and refluxed for 12 h, after the reaction was completed, the reaction liquid was quenched with 20% NaOH solution, and extracted with water and dichloromethane, the organic phase was separated and dried with anhydrous MgSO4, the solvent was removed under vacuum, and the residue was purified by column chromatography, eluent was ethyl acetate: dichloromethane = 1:10, to obtain compound B;

[0055] (3) A round-bottom flask was added with compound B (1.00 g, 4.2 mmol), 1,3-indanedione (0.73 g, 5 mmol), anhydrous ethanol (20 mL) and potassium methoxide (4.21 mg, 0.06 mmol), mixed, heated to 120℃ and reacted for 4 h, the reaction was monitored by TLC until the raw material point disappeared, the developing agent was dichloromethane: petroleum ether = 1:1, the mixture was cooled, precipitated, filtered, washed with anhydrous ethanol, dried with anhydrous MgSO4, and purified by column chromatography, eluent was dichloromethane: petroleum ether = 1:2, to obtain the molecular fluorescent probe for detecting Hg 2 + molecular fluorescent probe for detecting Hg

[0056] Performance test

[0057] 1, Compound A prepared in step (1) of Example 2, compound B prepared in step (2) of Example 2, and the molecular fluorescent probe prepared in step (3) of Example 2 were weighed and the yield was calculated respectively, and the results are shown in Table 1.

[0058] Table 1. Quality and yield of each product

[0059] Product Mass / g Yield / % Compound A 2.01 95.2 Compound B 1.19 90.4 Molecular fluorescent probe 1.32 85.4

[0060] As shown in Table 1, this preparation method has a high yield, high raw material utilization, and high economic benefits.

[0061] 2. Take compound A obtained in step (1) of Example 2, compound B obtained in step (2) of Example 2, and the molecular fluorescent probe obtained in step (3) of Example 2, and test them respectively. 1 HNMR spectra and 13 C NMR spectra, results as follows Figures 1-6 As shown.

[0062] Depend on Figure 1 It can be seen that, 1 H NMR (500MHz, CDCl3) δ7.20-7.11 (m, 2H), 7.06-6.95 (m, 4H), 6.93-6.85 (m, 2H), 4.19 (q, J=7.3Hz, 2H), 1.29 (t, J=7.2Hz, 3H).

[0063] Depend on Figure 2 It can be seen that, 13 C NMR (125MHz, CDCl3) δ144.53, 144.52, 135.42, 124.63, 123.32, 115.88, 115.83, 114.61, 114.58, 42.88, 13.50.

[0064] Depend on Figure 3 It can be seen that, 1 H NMR (500MHz, CDCl3) δ9.89 (t, J=1.0Hz, 1H), 7.46-7.39 (m, 2H), 7.31 (d, J=8.4Hz, 1H), 7.19 (dd, J=7.5, 1 .7Hz, 1H), 7.07-6.96 (m, 2H), 6.90 (dd, J=7.5, 1.6Hz, 1H), 4.18 (q, J=7.2Hz, 2H), 1.30 (t, J=7.2Hz, 3H).

[0065] Depend on Figure 4 It can be seen that, 13 C NMR (125MHz, CDCl3) δ191.90, 144.50, 144.35, 139.02, 135.42, 131.14, 127.23, 124.69, 123.21, 115.61, 115.51, 114.57, 112.35, 42.97, 13.50.

[0066] Depend on Figure 5 It can be seen that, 1 H NMR (500MHz, CDCl3) δ8.42 (d, J=0.9Hz, 1H), 7.97 (dd, J=5.9, 3.5Hz, 2H), 7.83 (dd, J=5.8, 3.6Hz, 2H), 7.44 (dd, J=8.4, 2.0Hz, 1H), 7.31 (d, J=8.5Hz, 1H) , 7.23 (dd, J=2.0, 1.0Hz, 1H), 7.17 (dd, J=7.6, 1.5Hz, 1H), 7.06-6.95 (m, 2H ), 6.89 (dd, J=7.7, 1.4Hz, 1H), 4.23 (q, J=7.2Hz, 2H), 1.31 (t, J=7.2Hz, 3H).

[0067] Depend on Figure 6 It can be seen that, 13 C NMR (125MHz, CDCl3) δ191.51, 191.21, 144.58, 144.35, 142.43, 136.45, 135.43, 133.03, 130. 92, 130.10, 129.74, 128.16, 124.62, 123.11, 118.22, 115.74, 114.57, 112.24, 42.79, 13.37.

[0068] 3. Dissolve the molecular fluorescent probe obtained in step (3) of Example 2 in EtOH / H2O solvent (1:2, v / v) to prepare a solution of 1×10 -5 3 mL of mol / L molecular fluorescent probe solution was added separately to Hg 2+ K + Ca 2+ Zn 2+ Al 3+ Mg 2+ Fe 3+ Mn 2+ Ag + Cd 2+ Cu 2+ Pb 2+ Na + A cation solution (EtOH:H2O = 1:2, v / v) was prepared to a concentration of 10. -5 A cation selectivity test was performed at mol / L, and the results are as follows: Figure 7 As shown.

[0069] Depend on Figure 7 It can be seen that this molecular fluorescent probe is effective against Hg. 2+The detection has high specificity, and the recognition process is hardly interfered by other metal ions, so that the Hg 2+ .

[0070] The foregoing description of the disclosed embodiments enables a person skilled in the art to make or use the application. Numerous modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be applied to other embodiments without departing from the spirit or scope of the application. Therefore, the present application is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for detecting Hg 2+ A molecular fluorescent probe, characterized in that, The structural formula is: .

2. A method for detecting Hg as described in claim 1 2+ The method for preparing molecular fluorescent probes is characterized by, Specifically, the following steps are included: (1) At room temperature, phenoxazine, anhydrous DMSO solution, sodium hydroxide and 1-bromoethane were mixed and stirred to react. After the reaction was completed, the reaction solution was quenched with water and extracted with ethyl acetate. The organic phase was separated and dried with anhydrous MgSO4 to remove the solvent. The residue was purified by column chromatography to obtain compound A. The structural formula of compound A is: ; (2) Under low temperature conditions, compound A, anhydrous DMF, POCl3 and anhydrous 1,2-dichloroethane were mixed and heated under reflux. After the reaction was completed, the reaction solution was quenched with 20% NaOH solution and extracted with water and dichloromethane. The organic phase was separated and dried with anhydrous MgSO4. The solvent was removed under vacuum and the residue was purified by column chromatography to obtain compound B. The structural formula of compound B is: The low-temperature conditions are -20℃ to 0℃. (3) Compound B, 1,3-indanedione, anhydrous ethanol and potassium methoxide were mixed and heated to react. The reaction was monitored by TLC until the starting material spot disappeared. The mixture was cooled, precipitated, filtered, washed with anhydrous ethanol, dried with anhydrous MgSO4, and purified by column chromatography to obtain the product used for Hg detection. 2+ Molecular fluorescent probes.

3. The method for detecting Hg as described in claim 2 2+ The method for preparing molecular fluorescent probes is characterized by, In step (1), the ratio of the amount of phenoxazine, anhydrous DMSO solution, sodium hydroxide and 1-bromoethane is 0.01mol:30mL:0.05mol:0.02mol.

4. The method for detecting Hg as described in claim 2 2+ The method for preparing molecular fluorescent probes is characterized by, In step (1), the stirring reaction time is 12-24 h; the eluent used in the column chromatography is ethyl acetate: petroleum ether = 1:

5.

5. The method for detecting Hg as described in claim 2 2+ The method for preparing molecular fluorescent probes is characterized by, In step (2), the ratio of compound A, anhydrous DMF, POCl3 and anhydrous 1,2-dichloroethane is 5.5 mmol: 3 mL: 5 mL: 25 mL.

6. The method for detecting Hg as described in claim 2 2+ The method for preparing molecular fluorescent probes is characterized by, In step (2), the temperature of the heating reflux reaction is 50-150℃ and the time is 12-36h; the eluent used in the column chromatography is ethyl acetate: dichloromethane = 1:

10.

7. The method for detecting Hg as described in claim 2 2+ The method for preparing molecular fluorescent probes is characterized by, In step (3), the ratio of compound B, 1,3-indanedione, anhydrous ethanol and potassium methoxide is 4.2 mmol: 5 mmol: 20 mL: 0.06 mmol.

8. The method for detecting Hg as described in claim 2 2+ The method for preparing molecular fluorescent probes is characterized by, In step (3), the heating reaction is carried out at a temperature of 50-120°C for 4-12 hours.

9. The method for detecting Hg as described in claim 2 2+ The method for preparing molecular fluorescent probes is characterized by, In step (3), the developing solvent for TLC monitoring is dichloromethane: petroleum ether = 1:1; the eluent used in column chromatography is dichloromethane: petroleum ether = 1:

2.

10. A molecular fluorescent probe as described in claim 1 for the preparation of a detector for Hg 2+ Applications in reagents.

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