A fluorescent probe and its preparation method and application in detecting cobalt ions

Abstract

The present invention relates to the field of metal ion detection technology, and specifically to a fluorescent probe and a preparation method thereof and an application thereof in detecting cobalt ions. The fluorescent probe is prepared from bipyridine as a basic raw material through coupling reaction, hydrazine reaction and hydrazone formation reaction. When the fluorescent probe encounters cobalt ions, obvious fluorescence quenching phenomenon will occur, thereby quickly and effectively identifying cobalt ions in aqueous solution. The technical solution of the present invention effectively solves the problems of high cost, complicated operation and strict requirements on operators in the prior art for instrument detection of cobalt ions, and achieves the purpose of quickly and efficiently detecting cobalt ions.

Description

Technical Field

[0001] The invention relates to the technical field of metal ion detection, and in particular to a fluorescent probe and a preparation method thereof and application thereof in detecting cobalt ions. Background Art

[0002] Cobalt is an essential trace element found in cobalamin and several other metalloproteins. As an essential component of vitamin B12 and enzymes, it plays an important role in iron metabolism and hemoglobin synthesis. However, when cobalt reaches a certain concentration in the human body, it can cause vasodilation, flushing, and cardiomyopathy. It can also adversely affect the blood and kidneys, as well as other diseases of the respiratory and central nervous systems. Dust, seawater, forest fires and volcanic eruptions, burning coal, as well as diamond polishing, chemical and cemented carbide industries can release cobalt into the environment. Therefore, detecting cobalt in the environment is essential to maintain human health.

[0003] Instrumental analysis methods are becoming more and more mature. Commonly used methods in element detection include atomic absorption spectroscopy, atomic fluorescence spectroscopy, inductively coupled plasma mass spectrometry, X-ray fluorescence spectroscopy, electrochemical analysis, etc. However, these methods usually require complex and expensive instruments, long sample pretreatment time, and require strictly trained professionals to complete the detection. In contrast, fluorescent probe detection (also called chemiluminescence detection, chemiluminescence sensing) has the advantages of high efficiency, simplicity, high sensitivity, good selectivity, low detection limit, and low cost.

[0004] Based on this, developing a fluorescent probe that can be used to detect cobalt ions has important practical significance for monitoring the cobalt element. Summary of the invention

[0005] In view of the problems in the prior art that the instrument detection of the presence of cobalt ions is expensive, the operation is complicated and the operator requirements are strict, the present invention provides a fluorescent probe and a preparation method thereof and an application in the detection of cobalt ions. The fluorescent probe is prepared from bipyridine as a basic raw material through coupling reaction, hydrazine reaction and hydrazone formation reaction. The fluorescent probe will show obvious fluorescence quenching phenomenon when encountering cobalt ions, and can quickly and effectively identify cobalt ions in aqueous solution, providing a new idea for the efficient detection of cobalt ions.

[0006] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0007] The first aspect of the present invention provides a fluorescent probe, the structural formula of the fluorescent probe is shown in formula (1):

[0008]

[0009] Formula (1).

[0010] Compared with the prior art, the present invention designs and synthesizes a fluorescent probe, which can realize specific recognition of cobalt ions. When cobalt ions are present, fluorescence quenching of the fluorescent probe can be induced. Cobalt ions are heavy metal ions with unfilled d orbitals, which can quench the luminescence of nearby luminophores through electron or energy transfer. When the fluorescent probe coexists with cobalt ions, the cobalt ions can interact with the -N, =O and -OH bonds in the fluorescent probe to bind the free cobalt ions, thereby interrupting the electron transfer between -NH, =O and bipyridine groups, resulting in fluorescence quenching, and thus achieving the purpose of rapid and efficient identification of cobalt ions. As shown below,

[0011]

[0012] The invention effectively solves the problems in the prior art that the instrument detection of the presence of cobalt ions is expensive, the operation is complicated and the requirements on operators are strict, and provides a new idea for the rapid and efficient detection of cobalt ions in aqueous solution.

[0013] Preferably, the method for preparing the fluorescent probe comprises the following steps:

[0014] Step 1, dissolving 2-tributyltinpyridine, ethyl 2-bromopyridine-4-carboxylate and a catalyst in an organic solvent, reflux for reaction for 40h-50h under an inert atmosphere, and removing the solvent to obtain a first compound;

[0015] Step 2, adding the first compound and hydrazine hydrate solution into an alcohol solvent, and performing hydrazine hydrolysis reaction at 80° C.-85° C. to obtain a second compound;

[0016] Step 3: dissolve the second compound in an alcohol solvent, slowly add 2-hydroxybenzaldehyde thereto, and reflux for 12 h to 16 h to obtain a fluorescent probe.

[0017] The present invention successfully prepares the fluorescent probe through coupling reaction, hydrazinolysis reaction and hydrazone formation reaction. The method for preparing the fluorescent probe of the present invention is simple, easy to operate, and has low raw material cost, which provides a new idea for rapid and efficient detection of cobalt ions.

[0018] Preferably, in step 1, the catalyst is tetrakis(triphenylphosphine)palladium.

[0019] Preferably, in step 1, the organic solvent is anhydrous toluene.

[0020] Preferably, in step 1, the molar ratio of 2-tributyltinpyridine to ethyl 2-bromopyridine-4-carboxylate is 1:1-1:1.1.

[0021] Preferably, in step 1, the molar ratio of the catalyst to the 2-tributyltinpyridine is 0.08:1-0.11:1.

[0022] Preferably, in step 1, the mass volume ratio of the 2-tributyltinpyridine to the organic solvent is 1g:6mL-1g:8mL.

[0023] Preferably, in step 2, the mass percentage of the solute in the hydrazine hydrate solution is 80%-85%.

[0024] Preferably, in step 2, the mass volume ratio of the first compound to the hydrazine hydrate solution is 1g:8mL-1g:10mL.

[0025] Preferably, in step 2, the alcohol solvent is anhydrous ethanol.

[0026] Preferably, in step 2, the mass volume ratio of the first compound to the alcohol solvent is 1g:30mL-1g:40mL.

[0027] Preferably, in step 2, the hydrazinolysis reaction time is 15h-20h.

[0028] Preferably, in step three, the alcohol solvent is anhydrous methanol.

[0029] Preferably, in step three, the mass volume ratio of the second compound to the alcohol solvent is 1g:25mL-1g:35mL.

[0030] Preferably, in step three, the molar ratio of the second compound to the aldehyde compound is 1:1-1:1.2.

[0031] The third aspect of the present invention provides an application of the fluorescent probe in detecting cobalt ions.

[0032] In summary, the present invention provides a fluorescent probe, which is prepared from bipyridine as a basic raw material through coupling reaction, hydrazine reaction and hydrazone formation reaction. When the fluorescent probe encounters cobalt ions, obvious fluorescence quenching occurs, thereby achieving the purpose of rapid and efficient detection of cobalt ions. The preparation method of the fluorescent probe provided by the present invention is simple and easy to operate. The use of the fluorescent probe effectively solves the problems of high cost, complex operation and strict operator requirements for instrument detection of cobalt ions in existing technologies, and provides a new idea for efficient detection of cobalt ions. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 The fluorescence emission spectrum of the fluorescent probe obtained in Example 1 before and after the addition of cobalt ions;

[0034] Figure 2This is a luminescence intensity bar graph of the fluorescent probe obtained in Example 1 that specifically recognizes cobalt ions;

[0035] Figure 3 The fluorescence emission spectra of the fluorescent probe obtained in Example 1 identifying cobalt ions with different equivalent concentrations;

[0036] Figure 4 This is a linear graph showing the change in the concentration ratio of the fluorescent probe obtained in Example 1 after adding cobalt ions. DETAILED DESCRIPTION

[0037] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0038] Example 1

[0039] This embodiment provides a fluorescent probe, which specifically includes the following contents:

[0040] Step 1: 4.9 g of 2-tributyltinpyridine, 3.1 g of ethyl 2-bromopyridine-4-carboxylate and 1.5 g of tetrakis(triphenylphosphine)palladium were mixed evenly, dissolved in 35 mL of dried toluene, and refluxed for 48 h under an inert atmosphere. After the reaction was completed, the solvent was removed, and the obtained solid was separated by column chromatography, with the eluent being dichloromethane and ethyl acetate in a volume ratio of 12:1, to obtain the first compound;

[0041] Step 2, dissolving 1.5 g of the first compound and 12 mL of 80 wt% hydrazine hydrate solution in 45 mL of anhydrous ethanol, performing hydrazinolysis reaction at 83 ° C for 18 h, cooling to room temperature, pouring the reaction system into 250 mL of deionized water, filtering, and vacuum drying the solid filtrate at 65 ° C and a vacuum degree of 0.7 MPa for 8 h to obtain a second compound;

[0042] Step 3: dissolve 0.8 g of the second compound in 25 mL of anhydrous methanol, slowly add 0.5 g of 2-hydroxybenzaldehyde thereto, reflux for 14 h, cool to room temperature, filter the reaction system, wash the solid filtrate three times with anhydrous methanol, and vacuum dry the solid filtrate at 70° C. and a vacuum degree of 0.7 MPa for 6 h to obtain a fluorescent probe.

[0043] After NMR testing, the NMR data of the fluorescent probe are as follows: 1H NMR (400 MHz, DMSO-D6, ppm): δ = 12.48 (s, 1H, -OH), 11.12 (s, 1H, –NH–), 8.90 (m, 2H, ArH), 8.76 (m, 2H,–CH=, ArH), 8.44 (d, 3 J = 4 Hz , 1H, ArH), 8.02 (t, 3 J = 8 Hz 1H, ArH), 7.93 (d, 3 J = 4Hz, 1H, ArH), 7.61 (d, 3 J = 4Hz, 1H, ArH), 7.53 (m, 1H, ArH), 7.33 (m, 1H, ArH), 6.95 (m, 2H, ArH).

[0044] Example 2

[0045] This embodiment provides a fluorescent probe, which specifically includes the following contents:

[0046] Step 1: 5.0 g of 2-tributyltinpyridine, 3.2 g of ethyl 2-bromopyridine-4-carboxylate and 1.5 g of tetrakis(triphenylphosphine)palladium were mixed evenly, dissolved in 35 mL of dried toluene, and refluxed for 48 h under an inert atmosphere. After the reaction was completed, the solvent was removed, and the obtained solid was separated by column chromatography, with the eluent being dichloromethane and ethyl acetate in a volume ratio of 12:1, to obtain the first compound;

[0047] Step 2, dissolving 1.6 g of the first compound and 15 mL of 85 wt% hydrazine hydrate solution in 45 mL of anhydrous ethanol, performing hydrazinolysis reaction at 83 ° C for 16 h, cooling to room temperature, pouring the reaction system into 250 mL of deionized water, filtering, and vacuum drying the solid filtrate at 65 ° C and a vacuum degree of 0.7 MPa for 8 h to obtain a second compound;

[0048] Step 3: dissolve 1.0 g of the second compound in 30 mL of anhydrous methanol, slowly add 0.5 g of 2-hydroxybenzaldehyde thereto, reflux for 14 h, cool to room temperature, filter the reaction system, wash the solid filtrate three times with anhydrous methanol, and vacuum dry the solid filtrate at 70° C. and a vacuum degree of 0.7 MPa for 6 h to obtain a fluorescent probe.

[0049] After NMR testing, the NMR data of the fluorescent probe are as follows: 1H NMR (400 MHz, DMSO-D6, ppm): δ = 12.48 (s, 1H, -OH), 11.12 (s, 1H, –NH–), 8.90 (m, 2H, ArH), 8.76 (m, 2H,–CH=, ArH), 8.44 (d, 3 J = 4 Hz , 1H, ArH), 8.02 (t, 3 J = 8 Hz 1H, ArH), 7.93 (d, 3 J = 4Hz, 1H, ArH), 7.61 (d, 3 J = 4Hz, 1H, ArH), 7.53 (m, 1H, ArH), 7.33 (m, 1H, ArH), 6.95 (m, 2H, ArH).

[0050] Example 3

[0051] This embodiment provides a fluorescent probe, which specifically includes the following contents:

[0052] Step 1: 4.5 g of 2-tributyltinpyridine, 3.0 g of ethyl 2-bromopyridine-4-carboxylate and 1.4 g of tetrakis(triphenylphosphine)palladium were mixed evenly, dissolved in 35 mL of dried toluene, and refluxed for 48 h under an inert atmosphere. After the reaction was completed, the solvent was removed, and the obtained solid was separated by column chromatography, with the eluent being dichloromethane and ethyl acetate in a volume ratio of 12:1, to obtain the first compound;

[0053] Step 2, dissolving 2.0 g of the first compound and 18 mL of 80 wt% hydrazine hydrate solution in 45 mL of anhydrous ethanol, performing hydrazinolysis reaction at 85 ° C. for 16 h, cooling to room temperature, pouring the reaction system into 300 mL of deionized water, filtering, and vacuum drying the solid filtrate at 65 ° C. and a vacuum degree of 0.7 MPa for 8 h to obtain a second compound;

[0054] Step 3: dissolve 1.1 g of the second compound in 35 mL of anhydrous methanol, slowly add 0.7 g of 2-hydroxybenzaldehyde thereto, reflux for 14 h, cool to room temperature, filter the reaction system, wash the solid filtrate three times with anhydrous methanol, and vacuum dry the solid filtrate at 70° C. and a vacuum degree of 0.7 MPa for 6 h to obtain a fluorescent probe.

[0055] After NMR testing, the NMR data of the fluorescent probe are as follows: 1H NMR (400 MHz, DMSO-D6, ppm): δ = 12.48 (s, 1H, -OH), 11.12 (s, 1H, –NH–), 8.90 (m, 2H, ArH), 8.76 (m, 2H,–CH=, ArH), 8.44 (d, 3 J = 4 Hz , 1H, ArH), 8.02 (t, 3 J = 8 Hz 1H, ArH), 7.93 (d, 3 J = 4Hz, 1H, ArH), 7.61 (d, 3 J = 4Hz, 1H, ArH), 7.53 (m, 1H, ArH), 7.33 (m, 1H, ArH), 6.95 (m, 2H, ArH).

[0056] In order to further demonstrate the technical effect of the present invention, the present invention conducted the following tests on the fluorescent probe obtained in Example 1: (1) Fluorescence emission spectrum test: The fluorescent probe obtained in Example 1 was dissolved in 10 mL of DMF / acetate buffer with a pH of 5 and a volume ratio of 9:1. The concentration of the fluorescent probe was 1×10 -5 mol / L, add 0.1mL of 1×10 - 3 mol / L cobalt chloride solution, under the test condition of excitation wavelength of 295nm, the emission spectrum test is carried out. The results are as follows Figure 1 As shown. Figure 1 It can be seen that the fluorescent probe provided in Example 1 of the present invention has a strong emission peak at 645 nm. After the addition of cobalt ions, the emission peak intensity is greatly reduced, indicating that cobalt ions have a fluorescence quenching effect on the fluorescent probe.

[0057] (2) Specific recognition: In order to further confirm the specific recognition of cobalt ions by the fluorescent probe, the fluorescent probe obtained in Example 1 was dissolved in 10 mL of DMF / acetate buffer with a pH of 5 and a volume ratio of 9:1. The concentration of the fluorescent probe was 1×10 -5 mol / L, prepare 9 parallel tests, add 0.1mL of 1×10 -3mol / L metal ion solutions (NaCl solution, KCl solution, MgCl2 solution, AlCl3 solution, CuSO4 solution, MnCl2 solution, ZnCl2 solution, FeCl2 solution and FeCl3 solution) were tested for specific identification of metal ions under the test condition of excitation wavelength of 295nm. On this basis, 0.1mL of 1×10 -3 mol / L cobalt chloride solution, the result is as follows Figure 2 The yellow column indicates that 1 equivalent of other metal ions is added to the fluorescent probe solution; the green column indicates that 1 equivalent of Co is added on the basis of 1 equivalent of other metal ions. 2+ .according to Figure 2 It can be seen that in the presence of other metal ions, the fluorescent probe obtained in Example 1 detects Co 2+ There was no obvious interference phenomenon when the fluorescent probe was used. 2+ A highly selective probe.

[0058] (3) Titration test: The fluorescent probe obtained in Example 1 was dissolved in 10 mL of DMF / acetate buffer with a pH of 5 and a volume ratio of 9:1. The concentration of the fluorescent probe was 1×10 -5 mol / L, 0.1mL of 1×10 -3 mol / L cobalt chloride solution, the amount of cobalt chloride solution added was 1.4mL, and the fluorescence emission spectrum was tested at a laser wavelength of 295nm each time the cobalt chloride solution was added. The results are as follows Figure 3 As shown. Figure 3 It can be seen that from 0.3−1.1 equivalent, as Co 2+ The addition of , the luminescence intensity of the fluorescent probe obtained in Example 1 at 645nm continued to decrease linearly; the linear fitting results are as follows Figure 4 As shown. Figure 4 It can be seen that the luminescence intensity of the fluorescent probe obtained in Example 1 increases with [Co 2+ ] / [fluorescent probe] changes with the change of the equation y=-391.08x+653.27, R 2 =0.9873 (y: luminous intensity, X: [Co 2+ ] / [Fluorescent probe], R 2 : correlation coefficient) was fitted, and the corresponding detection limit (detection limit is 3S / ρ, S: standard deviation of blank measurement value, ρ: slope) was calculated to be 8.32×10 -6 M.

[0059] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modification, equivalent substitution or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A fluorescent probe, characterized in that: The structural formula of the fluorescent probe is shown in formula (1): Formula (1).

2. The method for preparing a fluorescent probe according to claim 1, wherein: The steps include: Step 1, dissolving 2-tributyltinpyridine, ethyl 2-bromopyridine-4-carboxylate and a catalyst in an organic solvent, reflux for reaction for 40h-50h under an inert atmosphere, and removing the solvent to obtain a first compound; Step 2, adding the first compound and hydrazine hydrate solution into an alcohol solvent, and performing hydrazine hydrolysis reaction at 80° C.-85° C. to obtain a second compound; Step 3, dissolving the second compound in an alcohol solvent, slowly adding 2-hydroxybenzaldehyde thereto, and reflux reacting for 12h-16h to obtain a fluorescent probe; In step 1, the catalyst is tetrakis(triphenylphosphine)palladium; In step 1, the molar ratio of the catalyst to the 2-tributyltinpyridine is 0.08:1-0.11:

1.

3. The method for preparing a fluorescent probe according to claim 2, wherein: In step 1, the organic solvent is anhydrous toluene.

4. The method for preparing a fluorescent probe according to claim 2, wherein: In step 1, the molar ratio of 2-tributyltinpyridine to ethyl 2-bromopyridine-4-carboxylate is 1:1-1:1.1; and / or In step 1, the mass volume ratio of the 2-tributyltinpyridine to the organic solvent is 1g:6mL-1g:8mL.

5. The method for preparing a fluorescent probe according to claim 2, wherein: In step 2, the mass percentage of the solute in the hydrazine hydrate solution is 80%-85%; and / or In step 2, the mass volume ratio of the first compound to the hydrazine hydrate solution is 1g:8mL-1g:10mL.

6. The method for preparing a fluorescent probe according to claim 2, wherein: In step 2, the alcohol solvent is anhydrous ethanol; and / or In step 2, the mass volume ratio of the first compound to the alcohol solvent is 1g:30mL-1g:40mL; and / or In step 2, the hydrazinolysis reaction time is 15h-20h.

7. The method for preparing a fluorescent probe according to claim 2, wherein: In step 3, the alcohol solvent is anhydrous methanol.

8. The method for preparing a fluorescent probe according to claim 2, wherein: In step 3, the mass volume ratio of the second compound to the alcohol solvent is 1g:25mL-1g:35mL; and / or In step 3, the molar ratio of the second compound to the aldehyde compound is 1:1-1:1.

2.

9. Use of the fluorescent probe as claimed in claim 1 in detecting cobalt ions for non-diagnosis or treatment of diseases.

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