Novel organic fluorescent molecule, preparation method thereof and application of novel organic fluorescent molecule in iron ion detection

Abstract

The invention discloses a novel organic fluorescent molecule as well as a preparation method and application thereof in iron ion detection, the novel organic fluorescent molecule has a chemical structure as shown in the following formula I: # imgabs0. The novel organic fluorescent molecule provided by the invention is prepared by taking o-phenylenediamine and 2, 6-dialdehyde-1, 5-dihydroxynaphthalene as raw materials and methanol as a solvent through a one-step reaction. The fluorescent probe is prepared by Schiff base reaction and has the characteristic of wide excitation wavelength, and fluorescence emission at 624nm can be realized by excitation at 320-600nm; when Fe < 3 + > is added, the organic fluorescent molecules and Fe < 3 + > form a compound, fluorescence resonance energy transfer (FRET) fluorescence occurs between the organic fluorescent molecules and Fe < 3 + > to cause fluorescence quenching, qualitative and quantitative detection of Fe < 3 + > in a water environment can be realized according to fluorescence intensity change at 624nm, the organic fluorescent molecules have specific recognition performance on Fe < 3 + >, and the detection range is wide and is 1-300mu M.

Description

Technical Field

[0001] The present invention relates to the fields of fluorescent molecule synthesis and chemical sensors, and in particular to a novel organic fluorescent molecule, a preparation method thereof and application in iron ion detection. Background Art

[0002] Fe 3+ It is one of the most important trace elements in the human body and plays an important role in various physiological processes such as cell formation and metabolism, oxidation reactions, electron transfer, tissue respiration, enzyme catalysis, DNA and RNA synthesis. Excessive or insufficient iron intake will have adverse effects on the human body. For example, human iron deficiency can lead to iron deficiency anemia, decreased immune function, metabolic disorders, etc.; excessive iron intake can easily lead to liver tissue damage, hemochromatosis, Parkinson's disease, Alzheimer's disease and other diseases. Therefore, it is necessary to explore efficient and reliable detection of Fe 3+ The method of determining iron ions is particularly important for human life and health. Currently, the methods for determining iron ions include molecular absorption spectroscopy, high performance liquid chromatography, electrochemical method, atomic absorption spectroscopy, chemical titration, etc. However, complex instruments and tedious sample preparation procedures limit their practical application. Fluorescence analysis is widely used to detect Fe due to its simplicity and high sensitivity. 3+ However, most reported fluorescent sensors are bioincompatible, highly cytotoxic, and insoluble in physiological media. Therefore, developing new and efficient iron ion detection technologies to overcome the shortcomings of existing methods remains an important direction for future research. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a novel organic fluorescent molecule, a preparation method thereof and its application in iron ion detection in view of the above-mentioned deficiencies in the prior art. The present invention uses o-phenylenediamine and 2,6-dialdehyde-1,5-dihydroxynaphthalene as raw materials and methanol as solvent to react at 60°C to prepare the organic fluorescent molecule. The probe has the characteristics of a wide excitation wavelength, and can achieve fluorescence emission at 624nm when excited at 320-600nm; when Fe is added, the organic fluorescent molecule is obtained. 3+ Afterwards, the organic fluorescent molecules react with Fe 3+ The formation of a complex, the two undergo fluorescence resonance energy transfer (FRET) fluorescence, resulting in fluorescence quenching. The change in fluorescence intensity at 624 nm can be used to realize the Fe 3+ Qualitative and quantitative detection.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows: In the first aspect of the present invention, a novel organic fluorescent molecule is provided, which has a chemical structure as shown in the following formula I:

[0005]

[0006] Preferably, the novel organic fluorescent molecule is prepared by a Schiff base reaction using o-phenylenediamine and 2,6-dialdehyde-1,5-dihydroxynaphthalene as raw materials and methanol as solvent.

[0007] A second aspect of the present invention provides a method for preparing the novel organic fluorescent molecule as described above, comprising the following steps:

[0008] 1) adding o-phenylenediamine and 2,6-dialdehyde-1,5-dihydroxynaphthalene to methanol, ultrasonically dispersing, and then stirring to react to obtain a product solution;

[0009] 2) centrifuging the product solution obtained in step 1), collecting the solid at the bottom, and washing with methanol;

[0010] 3) The solid obtained in step 2) is placed in a vacuum dryer to obtain the novel organic fluorescent molecule.

[0011] Preferably, in step 1), the molar ratio of o-phenylenediamine to 2,6-dialdehyde-1,5-dihydroxynaphthalene is 2.5 to 10:1.

[0012] Preferably, in step 1), the stirring reaction temperature is 40-80° C., and the reaction time is 6-24 h.

[0013] Preferably, in step 1), the volume ratio of the sum of the masses of o-phenylenediamine and 2,6-dialdehyde-1,5-dihydroxynaphthalene to methanol is 1:25 to 1:100, measured in g by mass and mL by volume.

[0014] Preferably, the preparation method of the novel organic fluorescent molecule comprises the following steps:

[0015] 1) o-phenylenediamine and 2,6-dialdehyde-1,5-dihydroxynaphthalene were added to methanol at a molar ratio of 5:1, ultrasonically dispersed for 30 minutes, and then magnetically stirred at 60°C for 12 hours to obtain a product solution;

[0016] 2) centrifuging the product solution obtained in step 1), collecting the solid at the bottom, and washing it with methanol three times;

[0017] 3) The solid obtained in step 2) was placed in a vacuum drying oven at 60° C. and dried for 24 h to obtain the novel organic fluorescent molecule.

[0018] Preferably, in step 1), the volume ratio of the sum of the masses of o-phenylenediamine and 2,6-dialdehyde-1,5-dihydroxynaphthalene to methanol is 1:50, measured in g by mass and mL by volume.

[0019] The third aspect of the present invention provides an application of the novel organic fluorescent molecule described above in the detection of iron ions in water environment.

[0020] Preferably, the application method is:

[0021] Step 1: Disperse the novel organic fluorescent molecule in methanol to prepare a fluorescent molecule solution, and test the fluorescence intensity of the fluorescent molecule solution at 624 nm under an excitation light of 320-600 nm, which is recorded as F0;

[0022] Step 2: Mix the fluorescent material solution with different concentrations of iron ion standard solution and react for 5-20 minutes. Measure the fluorescence intensity of the resulting product at 624 nm under 320-600 nm excitation light, denoted as F, and construct a standard curve based on different iron ion concentrations and the corresponding F / F0 values;

[0023] Step 3: Monitor the fluorescence intensity of the solution obtained by mixing the water sample to be tested and the probe in a volume ratio of 1:1 at 624 nm under excitation light of 320-600 nm, record it as F', calculate the value of F' / F0, and use the pre-constructed standard curve to calculate the iron ion concentration in the sample to be tested.

[0024] The beneficial effects of the present invention are:

[0025] (1) The novel organic fluorescent molecule provided by the present invention is prepared by Schiff base reaction using o-phenylenediamine and 2,6-dialdehyde-1,5-dihydroxynaphthalene as raw materials and methanol as solvent. It has the characteristics of wide excitation wavelength, and can achieve fluorescence emission at 624nm when excited at 320-600nm. When Fe 3+ Afterwards, the organic fluorescent molecules react with Fe 3+ The formation of a complex, the two undergo fluorescence resonance energy transfer (FRET) fluorescence, resulting in fluorescence quenching. The change in fluorescence intensity at 624 nm can be used to realize the Fe 3+ Qualitative and quantitative detection of Fe 3+ It has specific recognition performance and a wide detection range: 1-300μM;

[0026] (2) The preparation method of the organic fluorescent molecule provided by the present invention is simple, has low equipment requirements, high yield, low cost, and can achieve large-scale preparation; in addition, the organic fluorescent molecule has stable luminescence and a wide excitation wavelength, and is particularly suitable for use as a probe in fluorescence sensing applications.

[0027] (3) The organic fluorescent molecules provided by the present invention are used to detect Fe in water environment 3+ The proposed method has the advantages of simple operation, rapidity, high efficiency, good specificity and low detection limit. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 NMR of the novel organic fluorescent molecule prepared in Example 21 H spectrum;

[0029] Figure 2 NMR of the novel organic fluorescent molecule prepared in Example 2 13 C spectrum;

[0030] Figure 3 This is a graph showing the quantum yield test results of the novel organic fluorescent molecule prepared in Example 2;

[0031] Figure 4 Graphs showing emission spectra of the novel organic fluorescent molecule prepared in Example 2 at different excitation wavelengths;

[0032] Figure 5 The fluorescence intensity changes at 624 nm after the novel organic fluorescent molecule prepared in Example 2 reacts with different metal ions;

[0033] Figure 6 The novel organic fluorescent molecule prepared in Example 2 and Fe 3+ Fluorescence spectra after different reaction times;

[0034] Figure 7 The new organic fluorescent molecules prepared in Example 2 and different concentrations of Fe 3+ Fluorescence intensity after reaction;

[0035] Figure 8 This is the standard curve constructed in Example 5. DETAILED DESCRIPTION

[0036] The present invention is further described in detail below with reference to the embodiments so that those skilled in the art can implement the invention with reference to the description.

[0037] It should be understood that terms such as “having”, “including” and “comprising” used herein do not preclude the existence or addition of one or more other elements or combinations thereof.

[0038] Unless otherwise specified, the experimental methods used in the following examples are conventional methods. Materials and reagents used in the following examples are commercially available unless otherwise specified. In the following examples, where specific conditions are not specified, the experiments were conducted under conventional conditions or those recommended by the manufacturer. Reagents and instruments used, where the manufacturer is not specified, are commercially available conventional products.

[0039] Example 1

[0040] A novel organic fluorescent molecule is prepared using o-phenylenediamine and 2,6-dialdehyde-1,5-dihydroxynaphthalene as raw materials and methanol as solvent via a Schiff base reaction. It has the chemical structure shown in Formula I below:

[0041]

[0042] Example 2

[0043] A method for preparing the novel organic fluorescent molecule of Example 1 comprises the following steps:

[0044] 1) o-phenylenediamine and 2,6-dialdehyde-1,5-dihydroxynaphthalene were added to methanol at a molar ratio of 5:1, ultrasonically dispersed for 30 minutes, and then magnetically stirred at 60°C for 12 hours to obtain a product solution;

[0045] The volume ratio of the sum of the mass of o-phenylenediamine and 2,6-dialdehyde-1,5-dihydroxynaphthalene to methanol is 1:50, with the mass unit being g and the volume unit being mL.

[0046] 2) centrifuging the product solution obtained in step 1), collecting the solid at the bottom, and washing it with methanol three times;

[0047] 3) The solid obtained in step 2) was placed in a vacuum drying oven at 60° C. and dried for 24 h to obtain the novel organic fluorescent molecule.

[0048] Example 3

[0049] A method for preparing the novel organic fluorescent molecule of Example 1 comprises the following steps:

[0050] 1) o-phenylenediamine and 2,6-dialdehyde-1,5-dihydroxynaphthalene were added to methanol in a molar ratio of 4:1, ultrasonically dispersed for 30 minutes, and then magnetically stirred at 60°C for 12 hours to obtain a product solution;

[0051] The volume ratio of the sum of the mass of o-phenylenediamine and 2,6-dialdehyde-1,5-dihydroxynaphthalene to methanol is 1:40, calculated in units of mass (g) and volume (mL).

[0052] 2) centrifuging the product solution obtained in step 1), collecting the solid at the bottom, and washing it with methanol three times;

[0053] 3) The solid obtained in step 2) was placed in a vacuum drying oven at 60° C. and dried for 24 h to obtain the novel organic fluorescent molecule.

[0054] Example 4

[0055] A method for preparing the novel organic fluorescent molecule of Example 1 comprises the following steps:

[0056] 1) o-phenylenediamine and 2,6-dialdehyde-1,5-dihydroxynaphthalene were added to methanol in a molar ratio of 6:1, ultrasonically dispersed for 30 minutes, and then magnetically stirred at 60°C for 12 hours to obtain a product solution;

[0057] The volume ratio of the sum of the mass of o-phenylenediamine and 2,6-dialdehyde-1,5-dihydroxynaphthalene to methanol is 1:60, with the mass unit being g and the volume unit being mL.

[0058] 2) centrifuging the product solution obtained in step 1), collecting the solid at the bottom, and washing it with methanol three times;

[0059] 3) The solid obtained in step 2) was placed in a vacuum drying oven at 60° C. and dried for 24 h to obtain the novel organic fluorescent molecule.

[0060] Example 5

[0061] The application of the novel organic fluorescent molecule prepared in Example 2 in the detection of iron ions is as follows:

[0062] Step 1: Disperse the novel organic fluorescent molecule in methanol to prepare a fluorescent molecule solution, and measure the fluorescence intensity of the fluorescent molecule solution at 624 nm under 460 nm excitation light, which is recorded as F0;

[0063] Step 2: Mix the fluorescent material solution with different concentrations of iron ion standard solution (aqueous solution containing iron ions) and react for 5-20 minutes. Test the fluorescence intensity of the obtained product at 624 nm under 320-600 nm excitation light, which is recorded as F;

[0064] Step 3: Monitor the fluorescence intensity of the solution obtained by mixing the water sample to be tested and the probe in a volume ratio of 1:1 at 624 nm under excitation light of 320-600 nm, record it as F', calculate the value of F' / F0, and use the pre-constructed standard curve to calculate the iron ion concentration in the sample to be tested.

[0065] The construction method of the standard curve is:

[0066] 1) Prepare a series of Fe 3+ aqueous solution;

[0067] 2) Disperse the fluorescent material in methanol to obtain a concentration of 0.1 mg mL -1 The fluorescent material solution is tested, and the fluorescence intensity of the fluorescent material solution at 624nm under 460nm excitation light is recorded as F0;

[0068] 3) To each Fe 3+ The same volume of fluorescent material solution was added to the aqueous solution, and after mixing for 10 minutes, the fluorescence intensity of the obtained products at 624 nm under 460 nm excitation light was measured, which was recorded as F; the value of F / F0 was used as the vertical axis, and the value of Fe 3+The concentration was used as the horizontal axis for curve fitting to obtain the standard curve.

[0069] Test Case

[0070] 1. NMR of the novel organic fluorescent molecule prepared in Example 2 1 H-ray and NMR 13 Figure C is as follows Figure 1 and Figure 2 As shown;

[0071] NMR 1 The H data is as follows: 1 H NMR (600MHz, DMSO-d6) δ15.16(s,2H,-OH),9.64(s,2H,H-6),8.68(d,J=9.2Hz,1H,H-1),7.42(dd,J=7.9,1.2Hz,2H,H-12),7.2 3(d,J=9.2Hz,2H,H-2),7.05(td,J=7.9,1.5Hz,2H,H-10),6.84(dd,J=8.0,1.4Hz,2H,H-9),6.70(td,J=7.7,1.4Hz,2H,H-11).

[0072] NMR 13 The C data is as follows: 13 C NMR(151MHz,DMSO)δ161.27(C-3),157.15(C-6),142.22(C-8),133.07(C-7),127.74 ,127.72,126.17,120.76,119.08,116.97,115.55,111.07(C-1,2,4,5,9,10,11,12).

[0073] 2. Reference Figure 3 , which is a graph showing the quantum yield test results of the new organic fluorescent molecule prepared in Example 2. The new organic fluorescent molecule was dispersed in methanol and the quantum yield was tested, with methanol serving as a blank. The results in the graph show that the probe quantum yield is 7.24%.

[0074] 3. Reference Figure 4 , which shows the emission spectra of the novel organic fluorescent molecule prepared in Example 2 at different excitation wavelengths. The spectra show that the probe has an optimal excitation wavelength of 460 nm and an optimal emission peak at 624 nm. As the excitation wavelength changes, the probe's emission peak position remains unchanged, while only the fluorescence intensity varies, demonstrating that the organic fluorescent molecule prepared in this invention is excitation wavelength independent.

[0075] 3. Reference Figure 5, is the change of fluorescence intensity at 624nm after the novel organic fluorescent molecule reacts with different metal ions; after different types of metal ions are mixed with the methanol solution of the novel organic fluorescent molecule prepared in Example 2, the change of the ratio of the fluorescence intensity at 624nm wavelength to the original intensity (F0, i.e., the fluorescence intensity of the methanol solution of the novel organic fluorescent molecule when not mixed with metal ions) is monitored. As can be seen in the figure, Fe 2+ and Fe 3+ The change is most obvious. 2+ Easily oxidized by air to Fe 3+ Therefore, iron in water is Fe 3+ Therefore, this probe is sensitive to Fe in water environment. 3+ It has strong specific recognition ability.

[0076] 4. Reference Figure 6 , is the novel organic fluorescent molecule prepared in Example 2 and Fe 3+ The fluorescence spectra after different reaction times show that the best reaction time is 10 min.

[0077] 5. Reference Figure 7 , which is a new organic fluorescent molecule with different concentrations of Fe 3+ The fluorescence intensity after the reaction was measured by preparing Fe 3+ The aqueous solution was mixed with the methanol solution of the novel organic fluorescent molecule prepared in Example 2, and the fluorescence spectrum under the excitation light of 460 nm was detected. The results showed that as Fe 3+ With the increase of concentration, the fluorescence intensity at 624 nm gradually decreased. Figure 8 The standard curve constructed in Example 5 shows a good curve relationship when the final concentration is 1-300 μM. The fitting curve equation is y=0.07+1.094*exp(-0.027*x), and the fitting coefficient R 2 =0.973. Where x is Fe 3+ The concentration of , y is F / F0.

[0078] Although the embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the description and implementation methods. They can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to specific details.

Claims

1. A novel organic fluorescent molecule, characterized in that: It has the chemical structure shown in the following formula I:

2. The novel organic fluorescent molecule according to claim 1, characterized in that: The invention uses o-phenylenediamine and 2,6-dialdehyde-1,5-dihydroxynaphthalene as raw materials and methanol as solvent and is prepared through Schiff base reaction.

3. A method for preparing the novel organic fluorescent molecule according to claim 1 or 2, characterized in that: The following steps are involved: 1) adding o-phenylenediamine and 2,6-dialdehyde-1,5-dihydroxynaphthalene to methanol, ultrasonically dispersing, and then stirring to react to obtain a product solution; 2) centrifuging the product solution obtained in step 1), collecting the solid at the bottom, and washing with methanol; 3) The solid obtained in step 2) is placed in a vacuum dryer to obtain the novel organic fluorescent molecule.

4. The method for preparing the novel organic fluorescent molecule according to claim 3, characterized in that: In step 1), the molar ratio of o-phenylenediamine to 2,6-dialdehyde-1,5-dihydroxynaphthalene is 2.5-10:

1.

5. The method for preparing the novel organic fluorescent molecule according to claim 3, characterized in that: In step 1), the stirring reaction temperature is 40-80° C. and the reaction time is 6-24 h.

6. The method for preparing the novel organic fluorescent molecule according to claim 3, characterized in that: In step 1), the volume ratio of the sum of the masses of o-phenylenediamine and 2,6-dialdehyde-1,5-dihydroxynaphthalene to methanol is 1:25 to 1:100, measured in g by mass and mL by volume.

7. The method for preparing the novel organic fluorescent molecule according to claim 3, characterized in that: The following steps are involved: 1) o-phenylenediamine and 2,6-dialdehyde-1,5-dihydroxynaphthalene were added to methanol at a molar ratio of 5:1, ultrasonically dispersed for 30 minutes, and then magnetically stirred at 60°C for 12 hours to obtain a product solution; 2) centrifuging the product solution obtained in step 1), collecting the solid at the bottom, and washing it with methanol three times; 3) The solid obtained in step 2) was placed in a vacuum drying oven at 60° C. and dried for 24 h to obtain the novel organic fluorescent molecule.

8. The method for preparing the novel organic fluorescent molecule according to claim 7, characterized in that: In step 1), the volume ratio of the sum of the masses of o-phenylenediamine and 2,6-dialdehyde-1,5-dihydroxynaphthalene to methanol is 1:50, with the mass unit being g and the volume unit being mL.

9. Use of the novel organic fluorescent molecule according to claim 1 or 2 in the detection of iron ions in water environment.

10. The use according to claim 9, characterized in that The application method is: Step 1: Disperse the novel organic fluorescent molecule in methanol to prepare a fluorescent molecule solution, and test the fluorescence intensity of the fluorescent molecule solution at 624 nm under an excitation light of 320-600 nm, which is recorded as F0; Step 2: Mix the fluorescent material solution with different concentrations of iron ion standard solution and react for 5-20 minutes. Measure the fluorescence intensity of the resulting product at 624 nm under 320-600 nm excitation light, denoted as F, and construct a standard curve based on different iron ion concentrations and the corresponding F / F0 values; Step 3: Monitor the fluorescence intensity of the solution obtained by mixing the water sample and the probe in a volume ratio of 1:1 at 624 nm under excitation light of 320-600 nm, record it as F', calculate the value of F' / F0, and use the pre-constructed standard curve to calculate the iron ion concentration in the sample to be tested.

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