Preparation method and application of fluorescent materials based on heterocyclic structures

Abstract

The present invention belongs to the technical field of fluorescent materials, and discloses a preparation method and application of fluorescent materials based on heterocyclic structures. The present invention uses thiazoline-2,4-dicarboxylic acid dimethyl ester, N-Boc-2-chloroethylamine, 4-bromo-1,8-naphthalic anhydride 4-vinylbenzene boronic acid, etc. as reactants, and prepares fluorescent materials based on heterocyclic structures by a novel and efficient preparation method. It contains a heterocyclic fluorescent chromophore group of naphthylimide and thiazoline, with high fluorescence intensity and good fluorescence performance. And it contains multiple carboxyl hydrophilic groups, which gives the fluorescent material good water solubility. At the same time, it contains a polymerizable alkenyl group, and under the action of azobisisobutyronitrile initiator, the polymer fluorescent material obtained by polymerization also has good fluorescence intensity and fluorescence performance. It can be applied to the fields of ceramic pigments, fluorescent coatings, and water-based fluorescent materials.

Description

Technical Field

[0001] The invention belongs to the technical field of fluorescent materials, and in particular relates to a preparation method and application of fluorescent materials based on heterocyclic structures. Background Art

[0002] Fluorescent materials are materials that can absorb light of a certain wavelength and then emit light of a different wavelength, and have unique fluorescent properties. They have important applications in fluorescent dyes, brighteners, OLED devices, signs and signs, etc. Fluorescent materials mainly include rare earth inorganic fluorescent materials, organic small molecule fluorescent materials, and polymer fluorescent materials. Among them, organic fluorescent materials have rich preparation methods, diverse fluorescent chromophores, novel structures, and can show different fluorescent properties, and are widely used.

[0003] Common organic fluorescent materials include naphthalene imide, coumarin, thiazoline, triazine, etc. The invention patent with the announcement number CN109970729B discloses the introduction of benzothiazole group at the 2-position of 1-hydroxynaphthalene imide, and the synthesized fluorescent dye has the characteristics of aggregated fluorescence enhancement, which can be used to design highly sensitive and selective fluoride ion fluorescent probe. However, the naphthalene imide fluorescent material is not water-soluble, which limits its practical application in water-soluble dyes and the like. Moreover, the naphthalene imide fluorescent material is a small molecule and does not have the characteristics of being polymerizable, which cannot meet its practical application in fluorescent polymer materials. Summary of the invention

[0004] The technical problem solved by the invention is to provide a method for preparing a fluorescent material based on a heterocyclic structure which is polymerizable, water-soluble and has high fluorescent performance.

[0005] The technical solution provided by the present invention is: a method for preparing a fluorescent material based on a heterocyclic structure, which comprises the following steps:

[0006] Step (1), add acetonitrile, thiazoline-2,4-dicarboxylic acid dimethyl ester, N-Boc-2-chloroethylamine, and potassium carbonate in a ratio of 1 mol: (1.2-1.8) mol: (2-3) mol to a reaction vessel equipped with a condenser reflux tube, heat to 65-80°C, react for 6-8 hours, filter after cooling, and rotary evaporate the filtrate. Add the product to dichloromethane, add trifluoroacetic acid, stir and react for 2-3 hours, and distill under reduced pressure. Dissolve the product in dichloromethane, add saturated sodium bicarbonate solution, extract and separate in a separatory funnel, collect the organic layer, dry over anhydrous sodium sulfate, rotary evaporate, and dry to obtain intermediate A.

[0007] Step (2), add ethanol, 1 mol: (1-1.6) mol of 4-bromo-1,8-naphthalene dicarboxylic anhydride, and intermediate A to a reaction vessel equipped with a condenser reflux tube, heat to 75-80°C, carry out imidization reaction for 3-5 hours, filter, heat the filtrate to volatilize, cool and recrystallize, then add the product to methanol, add a sodium hydroxide aqueous solution with a concentration of (3-4) mol / L, heat to 80-90°C, carry out hydrolysis reaction for 3-4 hours, cool, add dilute hydrochloric acid to adjust the pH to 2-3, precipitate, filter, and dry to obtain intermediate B.

[0008] Step (3), introducing nitrogen into a reaction vessel equipped with a condenser reflux tube, adding tetrahydrofuran, intermediate B, 4-vinylbenzeneboronic acid, and tetrakis(triphenylphosphine)palladium, stirring and dissolving, adding an aqueous potassium carbonate solution, rotary evaporating after the reaction, adding ethyl acetate, extracting and separating in a separatory funnel, collecting the organic layer, drying over anhydrous sodium sulfate, rotary evaporating, and separating the product by column chromatography to obtain a fluorescent material based on a heterocyclic structure.

[0009] Preferably, in step (3), the ratio of intermediate B, 4-vinylbenzeneboronic acid, tetrakis(triphenylphosphine)palladium, and potassium carbonate is 1 mol: (0.9-1.3) mol: (0.008-0.011) mol: (1.4-1.8) mol.

[0010] Preferably, in step (3), the reaction temperature is 75-90° C. and the reaction time is 18-24 h.

[0011] Preferably, the use of a fluorescent material based on a heterocyclic structure in the preparation of a polymer fluorescent material comprises the following steps: introducing nitrogen into a reaction container, adding toluene, a ratio of 1 mol: (0.004-0.005) mol of a fluorescent material based on a heterocyclic structure, and azobisisobutyronitrile, heating to 65-75° C., reacting for 4-6 hours, rotary evaporation, ethanol washing, and drying to obtain a polymer fluorescent material.

[0012] The technical effect of the present invention is: using thiazoline-2,4-dicarboxylic acid dimethyl ester, N-Boc-2-chloroethylamine, 4-bromo-1,8-naphthalene dicarboxylic anhydride 4-vinylbenzene boronic acid and the like as reactants, a fluorescent material based on a heterocyclic structure is prepared through a new and efficient preparation method. It contains fluorescent chromophores of naphthylimide and thiazoline heterocycles, and has high fluorescence intensity and good fluorescence performance. It also contains multiple carboxyl hydrophilic groups, which endows the fluorescent material with good water solubility. It also contains polymerizable alkenyl groups, and under the action of azobisisobutyronitrile initiator, the polymer fluorescent material obtained by polymerization also has good fluorescence intensity and fluorescence performance. It can be applied to the fields of ceramic pigments, fluorescent coatings, water-based fluorescent materials, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a reaction formula for preparing fluorescent materials based on heterocyclic structures.

[0014] Figure 2 It is the fluorescence emission spectrum of fluorescent materials based on heterocyclic structures.

[0015] Figure 3 is the fluorescence emission spectrum of polymer fluorescent materials. DETAILED DESCRIPTION

[0016] In order to facilitate the understanding of those skilled in the art, the present invention is further described below in conjunction with the embodiments, and the contents mentioned in the embodiments are not intended to limit the present invention. Unless otherwise specified, the technical means used in the embodiments are conventional means well known to those skilled in the art.

[0017] Example 1

[0018] Step (1), add 400mL acetonitrile, 60mmol thiazoline-2,4-dicarboxylic acid dimethyl ester (CAS No. 318233-97-5), 96mmol N-Boc-2-chloroethylamine (CAS No. 71999-74-1), 165mmol potassium carbonate to a reaction vessel equipped with a condenser reflux tube, heat to 65°C, react for 6h, filter after cooling, rotary evaporate the filtrate, add the product to 200mL dichloromethane, add 120mL trifluoroacetic acid, stir and react for 3h, distill under reduced pressure, dissolve the product in dichloromethane, add saturated sodium bicarbonate solution, extract and separate in a separatory funnel, collect the organic layer, dry over anhydrous sodium sulfate, rotary evaporate, and dry to obtain intermediate A. The structural formula is: .

[0019] Step (2), add 200 mL of ethanol, 60 mmol of 4-bromo-1,8-naphthalene dicarboxylic anhydride (CAS No. 81-86-7), and 78 mmol of intermediate A to a reaction vessel equipped with a condenser reflux tube, heat to 75°C, carry out imidization reaction for 5 hours, filter, heat the filtrate to volatilize, cool and recrystallize, then add the product to 150 mL of methanol, add 150 mL of 3 mol / L sodium hydroxide aqueous solution, heat to 90°C, carry out hydrolysis reaction for 3 hours, cool and add dilute hydrochloric acid to adjust the pH to 3, precipitate, filter, and dry to obtain intermediate B. The structural formula is: .

[0020] Step (3), nitrogen is introduced into a reaction vessel equipped with a condenser reflux tube, 600 mL of tetrahydrofuran, 50 mmol of intermediate B, 50 mmol of 4-vinylbenzene boronic acid (CAS No. 2156-04-9), 0.55 mmol of tetrakis(triphenylphosphine)palladium are added, and after stirring and dissolving, 300 mL of an aqueous solution containing 70 mmol of potassium carbonate is added, and the mixture is heated to 75°C, reacted for 24 hours, and rotary evaporated, and ethyl acetate is added. The mixture is extracted and separated in a separatory funnel, and the organic layer is collected, dried over anhydrous sodium sulfate, and rotary evaporated. The product is separated by column chromatography, and the eluent is a solution of ethyl acetate and petroleum ether, to obtain a fluorescent material based on a heterocyclic structure. The structural formula is .

[0021] Example 2

[0022] Step (1), add 300 mL of acetonitrile, 60 mmol of dimethyl thiazoline-2,4-dicarboxylate, 72 mmol of N-Boc-2-chloroethylamine, and 180 mmol of potassium carbonate to a reaction vessel equipped with a condenser reflux tube, heat to 80°C, react for 6 hours, filter after cooling, and rotary evaporate the filtrate. Add the product to 200 mL of dichloromethane, add 120 mL of trifluoroacetic acid, stir and react for 3 hours, and distill under reduced pressure. Dissolve the product in dichloromethane, add saturated sodium bicarbonate solution, extract and separate in a separatory funnel, collect the organic layer, dry over anhydrous sodium sulfate, rotary evaporate, and dry to obtain intermediate A.

[0023] Step (2), add 200 mL of ethanol, 60 mmol of 4-bromo-1,8-naphthalene dicarboxylic anhydride, and 96 mmol of intermediate A to a reaction vessel equipped with a condenser reflux tube, heat to 80°C, carry out imidization reaction for 3 hours, filter, heat the filtrate to volatilize, cool and recrystallize, then add the product to 150 mL of methanol, add 150 mL of 3 mol / L sodium hydroxide aqueous solution, heat to 90°C, carry out hydrolysis reaction for 3 hours, cool and add dilute hydrochloric acid to adjust the pH to 2, precipitate, filter, and dry to obtain intermediate B.

[0024] Step (3), nitrogen is introduced into a reaction vessel equipped with a condenser reflux tube, 700 mL of tetrahydrofuran, 50 mmol of intermediate B, 65 mmol of 4-vinylbenzeneboronic acid, and 0.4 mmol of tetrakis(triphenylphosphine)palladium are added, and after stirring and dissolving, 400 mL of an aqueous solution containing 70 mmol of potassium carbonate is added, and the mixture is heated to 90° C., reacted for 18 h, and rotary evaporated. Ethyl acetate is added, and extraction and separation are performed in a separatory funnel. The organic layer is collected, dried over anhydrous sodium sulfate, and rotary evaporated. The product is separated by column chromatography, and the eluent is a solution of ethyl acetate and petroleum ether, thereby obtaining a fluorescent material based on a heterocyclic structure.

[0025] Example 3

[0026] Step (1), add 400 mL of acetonitrile, 60 mmol of dimethyl thiazoline-2,4-dicarboxylate, 108 mmol of N-Boc-2-chloroethylamine, and 180 mmol of potassium carbonate to a reaction vessel equipped with a condenser reflux tube, heat to 70° C., react for 8 h, filter after cooling, and rotary evaporate the filtrate. Add the product to 300 mL of dichloromethane, add 180 mL of trifluoroacetic acid, stir and react for 2 h, and distill under reduced pressure. Dissolve the product in dichloromethane, add saturated sodium bicarbonate solution, extract and separate in a separatory funnel, collect the organic layer, dry over anhydrous sodium sulfate, rotary evaporate, and dry to obtain intermediate A.

[0027] Step (2), add 150 mL of ethanol, 60 mmol of 4-bromo-1,8-naphthalene dicarboxylic anhydride, and 60 mmol of intermediate A to a reaction vessel equipped with a condenser reflux tube, heat to 80° C., carry out imidization reaction for 5 hours, filter, heat the filtrate to volatilize, cool and recrystallize, then add the product to 150 mL of methanol, add 150 mL of 4 mol / L sodium hydroxide aqueous solution, heat to 85° C., carry out hydrolysis reaction for 4 hours, cool and add dilute hydrochloric acid to adjust the pH to 3, precipitate, filter, and dry to obtain intermediate B.

[0028] Step (3), nitrogen is introduced into a reaction vessel equipped with a condenser reflux tube, 800 mL of tetrahydrofuran, 50 mmol of intermediate B, 45 mmol of 4-vinylbenzeneboronic acid, and 0.55 mmol of tetrakis(triphenylphosphine)palladium are added, and after stirring and dissolving, 300 mL of an aqueous solution containing 70 mmol of potassium carbonate is added, and the mixture is heated to 80° C., reacted for 24 h, and rotary evaporated, ethyl acetate is added, and extraction and separation are performed in a separatory funnel, and the organic layer is collected, dried over anhydrous sodium sulfate, and rotary evaporated. The product is separated by column chromatography, and the eluent is a solution of ethyl acetate and petroleum ether, to obtain a fluorescent material based on a heterocyclic structure.

[0029] The yield and yield of the product in the test example are shown in Table 1.

[0030] Table 1 Product yield and yield

[0031]

[0032] Comparative Example 1

[0033] Step (1), add 200 mL of ethanol, 60 mmol of 4-bromo-1,8-naphthalene dicarboxylic anhydride, and 78 mmol of intermediate A to a reaction vessel equipped with a condenser reflux tube, heat to 75°C, carry out imidization reaction for 5 hours, filter, heat the filtrate to volatilize, cool and recrystallize to obtain intermediate C. The structural formula is: .

[0034] Step (2), nitrogen is introduced into a reaction vessel equipped with a condenser reflux tube, 600 mL of tetrahydrofuran, 50 mmol of intermediate C, 50 mmol of 4-vinylbenzeneboronic acid, 0.55 mmol of tetrakis(triphenylphosphine)palladium are added, and after stirring and dissolving, 300 mL of an aqueous solution containing 70 mmol of potassium carbonate is added, heated to 75°C, reacted for 24 hours, rotary evaporated, ethyl acetate is added, extracted and separated in a separatory funnel, the organic layer is collected, dried over anhydrous sodium sulfate, rotary evaporated, and the product is separated by column chromatography, and the eluent is a solution of ethyl acetate and petroleum ether to obtain a fluorescent material based on a heterocyclic structure. The structural formula is: .

[0035] Different masses of heterocyclic fluorescent materials were added to 100 mL of distilled water to prepare solutions with different mass concentrations, stirred and mixed, and the state of the solution was observed. The results are shown in Table 2.

[0036] Table 2 Water solubility of fluorescent materials

[0037]

[0038] After testing, it was found that the fluorescent material based on the heterocyclic structure contains multiple carboxyl groups, has good hydrophilicity and water solubility, and exhibits good water solubility at a mass concentration of 5-15g / L.

[0039] Comparative Example 2

[0040] Add 200 mL of ethanol, 60 mmol of 4-bromo-1,8-naphthalene dicarboxylic anhydride, and 78 mmol of n-propylamine to a reaction vessel equipped with a condenser reflux tube, heat to 75°C, perform imidization reaction for 5 hours, filter, heat the filtrate to volatilize, cool and recrystallize to obtain a fluorescent material. The structural formula is .

[0041] The fluorescent material based on the heterocyclic structure (prepared in Example 1) and the intermediate D (prepared in Comparative Example 2) were dissolved in dichloromethane to prepare a solution with a concentration of 0.003 mmol / L, and the fluorescence performance was tested using a fluorescence spectrometer. The fluorescence emission spectrum is shown in the specification. Figure 2 .

[0042] Attached to the instruction manual Figure 2 It can be seen that the fluorescent material prepared in Example 1 contains naphthylimide and thiazoline heterocyclic fluorescent chromophores, and its fluorescence intensity and fluorescence emission peak area are significantly higher than those of intermediate D.

[0043] Example 4

[0044] Nitrogen was introduced into the reaction vessel, 70 mL of toluene, 20 mmol of heterocyclic fluorescent material, and 0.08 mmol of azobisisobutyronitrile were added, and the mixture was heated to 75° C. and reacted for 4 h. The mixture was rotary evaporated, washed with ethanol, and dried to obtain a polymer fluorescent material with a yield of 8.12 g.

[0045] Example 5

[0046] Nitrogen was introduced into the reaction container, 80 mL of toluene, 20 mmol of heterocyclic fluorescent material, and 0.1 mmol of azobisisobutyronitrile were added, and the mixture was heated to 65° C. and reacted for 6 h. The mixture was rotary evaporated, washed with ethanol, and dried to obtain a polymer fluorescent material with a yield of 8.57 g.

[0047] It can be seen from Examples 4 and 5 that the fluorescent material based on the heterocyclic structure of the present invention has an active olefin group and can undergo a polymerization reaction to obtain a novel polymer fluorescent material.

[0048] The polymer fluorescent material prepared in Example 4 was added to dichloromethane to prepare a solution with a concentration of 5 g / L, and the fluorescence performance was tested using a fluorescence spectrometer. Figure 3 The fluorescence emission spectrum shows that the polymer fluorescent material also has strong fluorescence intensity and fluorescence properties.

[0049] Finally, it should be noted that the above embodiments of the present invention are only examples for illustrating the present invention, and are not intended to limit the implementation methods of the present invention. For those skilled in the art, other different forms of changes and modifications can be made based on the above description. It is impossible to list all implementation methods here. Any obvious changes or modifications derived from the technical solution of the present invention are still within the scope of protection of the present invention.

Claims

1. A method for preparing a fluorescent material based on a heterocyclic structure, characterized in that: The preparation method comprises: Step (1), adding acetonitrile, dimethyl thiazolidine-2,4-dicarboxylate, N-Boc-2-chloroethylamine, and potassium carbonate to a reaction vessel equipped with a condenser reflux tube, heating to 65-80° C., reacting for 6-8 hours, cooling and filtering, rotary evaporating the filtrate, adding the product to dichloromethane, adding trifluoroacetic acid, stirring and reacting for 2-3 hours, distilling under reduced pressure, dissolving the product in dichloromethane, extracting and separating, and drying to obtain intermediate A; Step (2), adding ethanol, 4-bromo-1,8-naphthalene dicarboxylic anhydride and intermediate A to a reaction vessel equipped with a condenser reflux tube, carrying out an imidization reaction, filtering, heating the filtrate to volatilize, cooling and recrystallizing, then adding the product to methanol, adding a sodium hydroxide aqueous solution, carrying out a hydrolysis reaction, cooling and adding dilute hydrochloric acid to adjust the pH to 2-3, precipitating a precipitate, filtering and drying to obtain intermediate B; Step (3), introducing nitrogen into a reaction vessel equipped with a condenser reflux tube, adding tetrahydrofuran, intermediate B, 4-vinylbenzeneboronic acid, and tetrakis(triphenylphosphine)palladium, stirring and dissolving, adding an aqueous potassium carbonate solution, rotary evaporation after the reaction, adding ethyl acetate, extracting and separating, and separating the product by column chromatography to obtain a fluorescent material based on a heterocyclic structure.

2. The method for preparing a fluorescent material based on a heterocyclic structure according to claim 1, characterized in that: In the step (1), the ratio of dimethyl thiazolidine-2,4-dicarboxylate, N-Boc-2-chloroethylamine, and potassium carbonate is 1 mol: (1.2-1.8) mol: (2-3) mol.

3. The method for preparing a fluorescent material based on a heterocyclic structure according to claim 1, characterized in that: In the step (2), the ratio of 4-bromo-1,8-naphthalene dicarboxylic anhydride to intermediate A is 1 mol: (1-1.6) mol.

4. The method for preparing a fluorescent material based on a heterocyclic structure according to claim 1, characterized in that: In the step (2), the concentration of the sodium hydroxide aqueous solution is (3-4) mol / L.

5. The method for preparing a fluorescent material based on a heterocyclic structure according to claim 1, characterized in that: In the step (2), the temperature of the imidization reaction is 75-80°C, and the reaction time is 3-5h; the temperature of the hydrolysis reaction is 80-90°C, and the reaction time is 3-4h.

6. The method for preparing a fluorescent material based on a heterocyclic structure according to claim 1, characterized in that: In the step (3), the ratio of intermediate B, 4-vinylbenzeneboronic acid, tetrakis(triphenylphosphine)palladium, and potassium carbonate is 1 mol: (0.9-1.3) mol: (0.008-0.011) mol: (1.4-1.8) mol.

7. The method for preparing a fluorescent material based on a heterocyclic structure according to claim 1, characterized in that: In the step (3), the reaction temperature is 75-90°C and the reaction time is 18-24h.

8. Use of a fluorescent material based on a heterocyclic structure obtained by the preparation method according to any one of claims 1 to 7 in the preparation of a polymer fluorescent material, characterized in that: The method comprises the following steps: introducing nitrogen into a reaction container, adding toluene, a fluorescent material based on a heterocyclic structure and azobisisobutyronitrile in a ratio of 1 mol: (0.004-0.005) mol, heating to 65-75° C., reacting for 4-6 hours, rotary evaporation, ethanol washing, and drying to obtain a polymer fluorescent material.

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