Fluorescent organic molecule as well as preparation method and application thereof

Abstract

The invention discloses a fluorescent organic molecule and a preparation method and application thereof.The preparation method of the fluorescent organic molecule comprises the following steps that S1, (E)-4, 4 '-(1, 2-diphenylethyl-1, 2-diyl) diphenylamine is dissolved in acetonitrile, and triethylamine is added; s2, dropwise adding 0.2 mol / L of an acetonitrile solution of a rhodamine B acyl chloride compound into the solution under vigorous stirring, stirring at room temperature, and reacting for 10-20 hours; after the reaction is finished, acetonitrile is removed, and residues are obtained; s3, the residues are dissolved with dichloromethane and washed with a saturated sodium bicarbonate aqueous solution, an obtained organic phase is dried with anhydrous sodium sulfate and filtered, finally, the organic phase is purified through column chromatography, and the faint yellow fluorescent organic molecules are obtained. The prepared fluorescent organic molecule can respectively emit green, blue and orange fluorescence under different induction conditions, shows excellent RGB (Red, Green and Blue) fluorescence characteristics, and has fluorescence characteristics of multiple stimulation responses.

Description

Technical Field

[0001] The present invention relates to the technical field of the preparation of organic molecules, and particularly belongs to a fluorescent organic molecule and its preparation method and application. Background Art

[0002] In recent years, stimulus-responsive organic fluorescent molecules have attracted much attention. Such molecules can exhibit reversible changes in luminescence characteristics under external stimuli such as temperature, pH, light, and chemical reagents, and have unique advantages and broad application prospects in many application fields, including display technology, bioimaging, environmental monitoring, disease diagnosis, intelligent materials, and biomedical engineering. Currently reported stimulus-responsive fluorescent molecules generally have the characteristic of single response and are difficult to meet the diversified application requirements, while the design of multi-stimulus-responsive fluorescent molecules poses great challenges.

[0003] Currently, the methods for achieving full-color display mainly rely on mixing luminescent materials of different colors, but this method has disadvantages such as impure color and narrow color gamut. Achieving RGB luminescence of a single organic molecule is of great significance for the development of high-performance full-color displays and multifunctional sensors. To achieve RGB luminescence of a single organic molecule, researchers have proposed various design strategies, such as combining multiple luminescent groups into one molecule or by mixing different forms of fluorescent molecules. However, these methods still have limitations, such as the problem of fluorescent mixed emission.

[0004] Aggregation-induced emission (AIE) refers to a phenomenon in which molecules that do not emit light or emit weakly in solution emit significantly enhanced light after aggregation. To achieve reversible RGB luminescence of a single organic molecule, AIE groups can be combined with stimulus-responsive fluorescent molecular switches. These molecular switches can undergo structural changes under the action of external stimuli, thereby changing the luminescence color of the molecule. Such RGB intelligent luminescent materials have broad application potential in the fields of information storage, optical encryption, intelligent display, and biological detection. Summary of the Invention

[0005] One of the purposes of the present invention is to provide a preparation method of a fluorescent organic molecule, and the technical solution adopted by the present invention is as follows:

[0006] A preparation method of a fluorescent organic molecule, comprising the following steps:

[0007] S1, dissolve (E)-4,4'-(1,2-diphenylethylene-1,2-diyl)dianiline in acetonitrile and add triethylamine;

[0008] S2, dropwise add an acetonitrile solution of 0.2 mol / L rhodamine B acyl chloride compound to the above solution under vigorous stirring, stir at room temperature, and the reaction time is 10 h - 20 h; after the reaction is completed, remove acetonitrile to obtain a residue;

[0009] S3. Dissolve the residue in dichloromethane, wash it with saturated aqueous sodium bicarbonate solution, dry the obtained organic phase with anhydrous sodium sulfate and filter it. Finally, purify the organic phase by column chromatography to obtain a pale yellow fluorescent organic molecule, and its molecular formula is:

[0010]

[0011] Among them, the molar ratio of (E)-4,4'-(1,2-diphenylethylene-1,2-diyl)dianiline to triethylamine is 1.2:9.

[0012] Among them, the preparation method of the rhodamine B acyl chloride compound is as follows: dissolve rhodamine B and phosphorus oxychloride in 1,2-dichloroethane, and reflux at heating for 4 - 8 hours; after the reaction is completed, remove 1,2-dichloroethane to obtain the acyl chloride compound of rhodamine B.

[0013] Among them, the molar ratio of the rhodamine to phosphorus oxychloride is 1:6.

[0014] Among them, the eluent used in the purification by column chromatography includes dichloromethane and ethyl acetate with a volume ratio of 50:1.

[0015] The second object of the present invention is to provide a fluorescent organic molecule, and the third object of the present invention is to provide a fluorescent organic molecule for fluorescent materials, and this fluorescent organic molecule is prepared by the above preparation method.

[0016] The steps for using this fluorescent organic molecule as a fluorescent material are as follows: dissolve the fluorescent organic molecule in tetrahydrofuran to form a fluorescent mother liquor, and then dilute the fluorescent mother liquor with a tetrahydrofuran solution containing a color-changing agent, wherein the volume ratio of the color-changing agent to tetrahydrofuran is 0 - 99:1, and the color-changing agent is water or trifluoroacetic acid.

[0017] The steps for using this fluorescent organic molecule as a fluorescent material are as follows: dissolve polymethyl methacrylate, propylene carbonate and the fluorescent organic molecule in dichloromethane, stir to dissolve, coat it on ordinary glass, and after the solvent completely volatilizes, obtain a fluorescent film; among them, the mass ratio of polymethyl methacrylate, propylene carbonate and the fluorescent organic molecule is 80:20:1; the stirring time is 4 h.

[0018] Among them, the unprocessed fluorescent film emits green fluorescence; the fluorescent film emits blue fluorescence after being irradiated with ultraviolet light with a wavelength of 365 nm at 70 °C for 5 minutes; the fluorescent film emits green fluorescence after being fumigated with trifluoroacetic acid, turns into orange-red fluorescence after being heated to 70 °C, and then emits blue fluorescence after the fluorescent film is fumigated with diethylamine.

[0019] Compared with the prior art, the implementation effects of the present invention are as follows: The present invention prepares a fluorescent organic molecule with a novel structure. The preparation method of this fluorescent organic molecule is simple and the cost is low; moreover, the prepared fluorescent organic molecule can emit green, blue, and orange-red fluorescence respectively under different induction conditions, showing excellent RGB fluorescence characteristics and having fluorescence characteristics of multiple stimulus responses. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 1H NMR spectrum of the fluorescent organic molecule in Example 1 of the present invention;

[0021] Figure 2 13C NMR spectrum of the fluorescent organic molecule in Example 1 of the present invention;

[0022] Figure 3 High-resolution mass spectrum of the fluorescent organic molecule in Example 1 of the present invention;

[0023] Figure 4 Fluorescence emission spectrum of the fluorescent organic molecule in Example 1 of the present invention in a mixed solvent of tetrahydrofuran and water with different ratios under 365 nm excitation;

[0024] Figure 5 Fluorescence emission spectrum of the fluorescent organic molecule in Example 1 of the present invention in a tetrahydrofuran solution with different concentrations of trifluoroacetic acid under 365 nm excitation;

[0025] Figure 6 Fluorescence excitation and emission spectra of the tetrahydrofuran solution of the fluorescent organic molecule in Example 1 of the present invention after ultraviolet irradiation;

[0026] Figure 7 Fluorescence emission spectrum of the fluorescent thin film of the fluorescent organic molecule in Example 1 of the present invention under 365 nm excitation. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0027] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0028] Example 1

[0029] Preparation of the fluorescent organic molecule:

[0030] S1. Dissolve 2 mmol of rhodamine B and 12 mmol of phosphorus oxychloride in 10 mL of 1,2-dichloroethane, and reflux for 4 hours. After the reaction, rotary evaporate to remove 1,2-dichloroethane to obtain a rhodamine B acyl chloride compound. This acyl chloride compound is dissolved in 10 mL of acetonitrile for standby. The concentration of the acetonitrile solution of this rhodamine B acyl chloride compound is 0.2 mol / L. The concentration of the acetonitrile solution of the rhodamine B acyl chloride compound in this example is one of them. Specifically, during the preparation process, technicians can adjust the concentration.

[0031] S2. Dissolve 2.4 mmol of (E)-4,4'-(1,2-diphenylethylene-1,2-diyl)dianiline in 20 mL of acetonitrile, add 18 mmol of triethylamine, and slowly dropwise add the acetonitrile solution of the rhodamine B acyl chloride compound to the above mixture under vigorous stirring, and stir at room temperature for 12 h. After the reaction, rotary evaporate to remove acetonitrile, dissolve the residue in dichloromethane, and wash it three times with saturated sodium bicarbonate aqueous solution. The organic phase is dried with anhydrous sodium sulfate and filtered; the final product is purified by column chromatography (silica gel, eluent: dichloromethane:ethyl acetate = 50:1) to obtain a light yellow fluorescent organic molecule solid product.

[0032] The preparation reaction steps of this fluorescent organic molecule are as follows:

[0033]

[0034] The prepared fluorescent organic molecule was analyzed by nuclear magnetic resonance to obtain its nuclear magnetic resonance hydrogen spectrum (using a Bruker-400MHz nuclear magnetic resonance spectrometer of Bruker Corporation), as Figure 1 shown. 1 H NMR(400MHz,DMSO-d6)δ7.85(d,J=6.4Hz,1H),7.60-7.47(m,2H),7.11-6.95(m,7H),6.91-6.83(m,2H),6.80-6.72(m,2H),6.60(d,J=8.2Hz,2H),6.56-6.38(m,6H),6.38-6.20(m,6H),5.07(s,2H),3.35-3.21(m,8H),1.07(t,J=6.9Hz,12H).

[0035] The prepared fluorescent organic molecule was analyzed by nuclear magnetic resonance to obtain its nuclear magnetic resonance carbon spectrum (using a Bruker-400MHz nuclear magnetic resonance spectrometer of Bruker Corporation), as Figure 2 shown. 1313C NMR (100 MHz, DMSO-d6) δ 167.0, 153.7, 152.7, 148.7, 147.7, 144.4, 143.9, 142.1, 141.6, 137.6, 135.3, 133.8, 132.1, 131.2, 131.1, 131.1, 130.6, 130.3, 128.9, 128.8, 128.2, 127.9, 126.6, 126.5, 125.3, 124.3, 123.3, 113.5, 108.5, 106.1, 97.6, 67.0, 44.1, 12.9.

[0036] The prepared fluorescent organic molecule was analyzed using a mass spectrometer (Waters TM Q-TOF Premier), and the result HRMS (ESI) m / z was obtained as Figure 3 shown. For C 54 H 50 N4O2 [M+H] + the calculated value was 787.4007 and the measured value was 787.4006.

[0037] Then, the fluorescent emission test of the fluorescent organic molecule in this example was carried out (the test used a F-4600 fluorescence spectrophotometer from HITACHI and a UV-3600 ultraviolet-visible (UV-vis) spectrophotometer from Shimadzu Corporation):

[0038] (1) Fluorescent emission of the fluorescent organic molecule in mixed solvents of tetrahydrofuran and water with different volume ratios

[0039] 7.9 mg of the fluorescent organic molecule was weighed and dissolved in 1 mL of tetrahydrofuran. Then, 25 μL of the solution was taken and diluted in 10 mL of mixed solvents of tetrahydrofuran and water with different volume ratios, and a fluorescent organic molecule solution with a concentration of 2.5×10 -5 mol / L could be prepared. The volume ratio of water to tetrahydrofuran was as low as 99:1 and as high as 4:1. The aqueous tetrahydrofuran solution within this concentration range did not have a particularly significant impact on the fluorescence color. The fluorescent emission of the fluorescent organic molecule in mixed solvents of tetrahydrofuran and water with different volume ratios was tested under excitation at a wavelength of 365 nm, and the emitted fluorescence was green. The green fluorescence emission spectrum is shown in Figure 4 .

[0040] (2) Fluorescent emission of the fluorescent organic molecule in tetrahydrofuran solutions with different concentrations of trifluoroacetic acid

[0041] Weigh 7.9 mg of the fluorescent organic molecule and dissolve it in 1 mL of tetrahydrofuran. Then, pipette 25 μL of the solution and dilute it in 10 mL of tetrahydrofuran containing trifluoroacetic acid (the concentrations of trifluoroacetic acid are successively: 0.01 M, 0.05 M, 0.1 M, 0.2 M, 0.3 M, 0.4 M, 0.5 M, 0.6 M, 0.7 M, 0.8 M, 0.9 M, 1.0 M), and the tetrahydrofuran solution of the fluorescent organic molecule containing different concentrations of trifluoroacetic acid can be prepared. Test the fluorescence emission of the fluorescent organic molecule in tetrahydrofuran with different concentrations of trifluoroacetic acid under excitation at a wavelength of 365 nm. The emitted fluorescence is orange-red, and the orange-red fluorescence emission spectrum is shown in Figure 5 .

[0042] (3) Fluorescence test of the tetrahydrofuran solution of the fluorescent organic molecule after ultraviolet irradiation

[0043] Weigh 7.9 mg of the fluorescent organic molecule and dissolve it in 1 mL of tetrahydrofuran. Then, pipette 25 μL of the solution and dilute it in 10 mL of tetrahydrofuran, and the tetrahydrofuran solution of the fluorescent organic molecule with a concentration of 2.5×10 -5 mol / L can be prepared. After irradiation with ultraviolet light at 365 nm for 5 minutes, test its fluorescence emission under excitation at a wavelength of 365 nm. The emitted fluorescence is blue, and the blue fluorescence emission spectrum is shown in Figure 6 .

[0044] (4) Study on the fluorescence properties of the fluorescent film

[0045] Dissolve 0.8 g of polymethyl methacrylate, 0.2 g of propylene carbonate and 10 mg of the fluorescent organic molecule in 5 mL of dichloromethane, stir for 4 h to dissolve, and coat it on ordinary glass. After the solvent has completely volatilized, a fluorescent film is obtained.

[0046] The fluorescent film prepared by the above process emits green fluorescence without treatment ( Figure 7 shown by the G curve in); the fluorescent film emits blue fluorescence after irradiation with ultraviolet light at a wavelength of 365 nm at 70 °C for 5 minutes ( Figure 7 shown by the B curve in); the fluorescent film emits green fluorescence after fumigation with trifluoroacetic acid for 1 minute and turns into orange-red fluorescence after heating to 70 °C ( Figure 7 shown by the R curve in), and then the fluorescent film emits blue fluorescence after fumigation with diethylamine for 1 minute.

[0047] Example 2

[0048] The difference from Example 1 is that 2 mmol of rhodamine B and 12 mmol of phosphorus oxychloride are dissolved in 10 mL of 1,2-dichloroethane and heated under reflux for 6 hours.

[0049] Example 3

[0050] It is different from Example 1 in that 2 mmol of rhodamine B and 12 mmol of phosphorus oxychloride are dissolved in 10 mL of 1,2-dichloroethane and heated under reflux for 8 hours.

[0051] Example 4

[0052] It is different from Example 1 in that 2.4 mmol of (E)-4,4'-(1,2-diphenylethylene-1,2-diyl)dianiline is dissolved in 20 mL of acetonitrile, 18 mmol of triethylamine is added, and the acetonitrile solution of the rhodamine B acyl chloride compound is slowly added dropwise to the above mixture under vigorous stirring, and stirred at room temperature for 10 h.

[0053] Example 5

[0054] It is different from Example 1 in that 2.4 mmol of (E)-4,4'-(1,2-diphenylethylene-1,2-diyl)dianiline is dissolved in 20 mL of acetonitrile, 18 mmol of triethylamine is added, and the acetonitrile solution of the rhodamine B acyl chloride compound is slowly added dropwise to the above mixture under vigorous stirring, and stirred at room temperature for 15 h.

[0055] Example 6

[0056] It is different from Example 1 in that 2.4 mmol of (E)-4,4'-(1,2-diphenylethylene-1,2-diyl)dianiline is dissolved in 20 mL of acetonitrile, 18 mmol of triethylamine is added, and the acetonitrile solution of the rhodamine B acyl chloride compound is slowly added dropwise to the above mixture under vigorous stirring, and stirred at room temperature for 20 h.

[0057] In addition, when performing fluorescence testing in the present invention, in addition to 70 °C, other temperatures can also be used for the heating temperature of the fluorescent film, such as any temperature between 40 °C and 90 °C. The temperature affects the speed of fluorescence change and the emission intensity, and will not have any impact on the fluorescence color. Therefore, using the fluorescent film of the present invention within the temperature range of 40 °C to 90 °C also falls within the protection scope of the present invention.

[0058] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a fluorescent organic molecule, characterized in that: The following steps are involved: S1, dissolving (E)-4,4'-(1,2-diphenylethylene-1,2-diyl)diphenylamine in acetonitrile, and adding triethylamine; S2, adding the acetonitrile solution of rhodamine B acyl chloride compound dropwise to the above solution under vigorous stirring, stirring at room temperature, and the reaction time is 10h-20h; after the reaction is completed, removing the acetonitrile to obtain a residue; S3, dissolving the residue with dichloromethane and washing with saturated sodium bicarbonate aqueous solution, drying the obtained organic phase with anhydrous sodium sulfate and filtering, and finally purifying the organic phase by column chromatography to obtain a light yellow fluorescent organic molecule, whose molecular formula is:

2. The method for preparing fluorescent organic molecules according to claim 1, characterized in that: The molar ratio of the (E)-4,4'-(1,2-diphenylethylene-1,2-diyl)diphenylamine to triethylamine is 1.2:

9.

3. The method for preparing fluorescent organic molecules according to claim 1, characterized in that: The preparation method of the rhodamine B acyl chloride compound is as follows: rhodamine B and phosphorus oxychloride are dissolved in 1,2-dichloroethane, and heated under reflux for 4-8 hours; after the reaction is completed, 1,2-dichloroethane is removed to obtain the rhodamine B acyl chloride compound.

4. The method for preparing fluorescent organic molecules according to claim 3, characterized in that: The molar ratio of the rhodamine to phosphorus oxychloride is 1:

6.

5. A fluorescent organic molecule, characterized in that: Prepared by the preparation method according to any one of claims 1 to 5.

6. The use of the fluorescent organic molecule according to claim 5, characterized in that: For fluorescent materials.

7. The use of the fluorescent organic molecule according to claim 5, characterized in that: For fluorescent materials; the steps are: dissolving fluorescent organic molecules in tetrahydrofuran to form a fluorescent mother solution, and then diluting the fluorescent mother solution with a tetrahydrofuran solution containing a color-changing agent, wherein the volume ratio of the color-changing agent to tetrahydrofuran is 0-99:1, and the color-changing agent is water or trifluoroacetic acid.

8. The use of the fluorescent organic molecule according to claim 5, characterized in that: Used for fluorescent materials; the steps are: dissolving polymethyl methacrylate, propylene carbonate and fluorescent organic molecules in dichloromethane, stirring to dissolve, coating on ordinary glass, and removing the solvent to obtain a fluorescent film.

9. The use of fluorescent organic molecules according to claim 8, characterized in that: The mass ratio of polymethyl methacrylate, propylene carbonate and fluorescent organic molecules is 80:20:1; the stirring time is 4h.

10. The use of fluorescent organic molecules according to claim 8, characterized in that: The fluorescent film emits green fluorescence when it is not treated; the fluorescent film emits blue fluorescence after being irradiated with ultraviolet light of a wavelength of 365nm at 70°C for 5 minutes; the fluorescent film emits green fluorescence after being fumigated with trifluoroacetic acid, and turns into orange-red fluorescence after being heated to 70°C, and then the fluorescent film emits blue fluorescence after being fumigated with diethylamine.

Images