Doped red organic room-temperature phosphorescent material based on red phosphorescent emitter and preparation method of doped red organic room-temperature phosphorescent material

Abstract

The invention belongs to the technical field of synthesis of organic room-temperature phosphorescent materials, and particularly relates to a doped red organic room-temperature phosphorescent material based on a red phosphorescent emitter and a preparation method of the doped red organic room-temperature phosphorescent material. The structure of the red phosphorescent emitter is shown as a formula I. The red phosphorescent emitter is novel in molecular structure, easy to prepare and stable in property. The invention also provides a red organic room-temperature phosphorescent material which has the characteristics of ultra-long service life and high brightness. Experimental data show that the longest red phosphorescence life of the material can reach 794 ms, and meanwhile, the phosphorescence quantum yield of the material is as high as 12.3%.

Description

Technical Field

[0001] The present application belongs to the technical field of synthesis of organic room temperature phosphorescent materials, and in particular relates to a doped red organic room temperature phosphorescent material based on a red phosphorescent emitter and a preparation method thereof. Background Art

[0002] In recent years, a large number of long-life ( τ P ) and high phosphorescence quantum yield ( Φ P ) organic room temperature phosphorescent materials. However, due to the small ground-excited state energy gap of the red phosphorescent emitter, red phosphorescence is more susceptible to non-radiative transitions. Therefore, compared with phosphorescent materials of other colors, red organic room temperature phosphorescent materials with excellent properties were extremely rare before 2022 (Adv. Optical Mater. 2021, 2002197). Since 2022, with the continuous heating up of research in this field, some single-component, eutectic, film, host-guest doped materials with red room temperature phosphorescent properties have been reported one after another. However, according to the El-sayed rule, τ P and Φ P Therefore, we should have both strengths and weaknesses. τ P With high Φ P High-performance red room-temperature phosphorescent materials are still very difficult to produce.

[0003] Currently, among the few τ P >100 ms and Φ P In the red organic room temperature phosphorescent materials with a content of >5% (Adv. Optical Mater. 2023, 2302482; Chem. Eng. J. 2024, 492, 152419; Nat. Commun. 2022, 13, 186; Adv. Sci. 2024, 11, 2308897), the red phosphorescent luminophores are all condensed aromatic hydrocarbons (such as pyrene and dibenzo[g,p]condensed dinaphthalene, etc.) as luminophores. This type of luminophore mainly utilizes the lower energy gap of condensed aromatic hydrocarbons and the rigidity of their own structure to obtain a long-lasting τ P With high Φ P The red room temperature phosphorescence emission of 2,10-diphenoxazine-dibenzo[g,p]-fused dinaphthalene (guest) / β-estradiol (host) system has the best performance. τ P=640 ms and Φ P =8.7% (Adv. Sci. 2024, 11, 2308897). However, the synthesis steps of this guest are cumbersome, and the host can be absorbed through the skin and has hormonal activity. In addition, condensed aromatic ring guest molecules such as pyrene are also highly carcinogenic.

[0004] Therefore, it is an extremely difficult task to get rid of the constraints of the condensed aromatic ring structure through new molecular engineering design strategies, obtain a new type of red phosphorescent emitter that is easy to prepare, and screen a matching host to surpass the current red organic room temperature phosphorescent materials in performance. Summary of the invention

[0005] The purpose of the present invention is to solve the deficiencies of the prior art and provide a doped red organic room temperature phosphorescent material based on a red phosphorescent emitter and a preparation method thereof, which specifically adopts the following technical solutions: In a first aspect, the present invention provides a red phosphorescent emitter (NBMCy-B4), the structure of which is shown in Formula I: Formula I.

[0006] In a second aspect, the present invention further provides a method for preparing the above-mentioned red phosphorescent emitter, comprising the following steps: Under argon protection, 4-chloro-1-methyl-quinoline perchlorate and 1,3-dimethylbarbituric acid boron fluoride complex are used as raw materials, and heated in a polar solvent in the presence of an organic base to react. After the reaction, isopropyl ether is added to precipitate the product. The crude product is centrifuged and subjected to silica gel column chromatography to obtain the red phosphorescent emitter (NBMCy-B4).

[0007] As a further preferred embodiment, the organic base is any one of triethylamine, diisopropylethylamine, triethylenediamine, tetramethylethylenediamine, and 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU).

[0008] As a further preferred embodiment, the solvent is any one of dimethylformamide, dimethyl sulfoxide, dimethylacetamide, and N-methylpyrrolidone.

[0009] As a further preferred embodiment, the reaction time of the above reaction is 40°C-80°C, and the reaction time of the reaction is 30 min-120 min.

[0010] In a third aspect, the present invention provides a red organic room temperature phosphorescent material, which includes the above-mentioned red phosphorescent emitter.

[0011] As a further preferred embodiment, the above-mentioned red organic room temperature phosphorescent material also includes any one of 5-methoxytetralone, 4-methoxybenzophenone, 2-benzoylthiophene, 4-bromobenzophenone, 3,4-dimethoxyacetophenone, 6-methoxyindanone, 2-benzoylpyridine, and 7-methoxytetralone.

[0012] In a fourth aspect, the present invention provides a method for preparing the above-mentioned red organic room temperature phosphorescent material, comprising the following steps: Dissolving the above-mentioned red phosphorescent emitter and host material in organic solvents to obtain red phosphorescent emitter mother solution and host mother solution respectively; The red phosphorescent emitter mother solution and the main body mother solution are mixed, concentrated and dried to obtain an amorphous red room temperature phosphorescent material; The amorphous red room temperature phosphorescent material is heated, poured into a mold after melting, and cooled to room temperature to obtain the red organic room temperature phosphorescent material; The host material is one of 5-methoxytetralone, 4-methoxybenzophenone, 2-benzoylthiophene, 4-bromobenzophenone, 3,4-dimethoxyacetophenone, 6-methoxyindanone, 2-benzoylpyridine, and 7-methoxytetralone. Most preferably, the host material is 5-methoxytetralone. Experimental tests show that the NBMCy-B4 / 5-methoxytetralone material has the longest phosphorescence lifetime and the highest quantum yield.

[0013] As a further preferred embodiment, the molar ratio of the host material to the red phosphorescent emitter is 1000: 3-10000: 1. When the ratio is lower than 10000: 1, the red phosphorescence of the material is difficult to be observed by the naked eye; when the ratio is greater than 1000: 3, the red phosphorescent emitter will aggregate, resulting in a significant reduction in the phosphorescent emission intensity.

[0014] As a further preferred embodiment, the organic solvent includes at least one of dichloromethane, chloroform, tetrahydrofuran, dioxane, ethyl acetate, acetonitrile, methanol, ethanol, and dimethylformamide.

[0015] The beneficial effects of the present invention are: The present invention provides a red phosphorescent emitter (NBMCy-B4) with a novel molecular structure, which is easy to prepare and has stable properties. In addition, the present invention also provides a method for preparing a red organic room temperature phosphorescent material, which adopts a "double locking" strategy through molecular engineering design; firstly, multiple intramolecular interactions are introduced into the guest structure to enhance the molecular rigidity (first locking); secondly, a special host that can have a strong intermolecular interaction with the guest molecule is selected to enhance the host-guest Dexter triplet energy transfer while suppressing non-radiative transitions (second locking), thereby obtaining a red organic room temperature phosphorescent material with both long τP With high Φ P The data results of the examples show that the NBMCy-B4 / 5-methoxytetralinone (1000:3 molar ratio) red room temperature phosphorescent material provided by the present invention has the best performance. τ P =794 ms and Φ P =12.3%. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0017] Figure 1 The fluorescence emission spectrum, phosphorescence emission spectrum and phosphorescence quantum yield of the red organic room temperature phosphorescent material provided in Example 2 of the present application; Figure 2 is a phosphorescence lifetime diagram of a red organic room temperature phosphorescent material provided in Example 2 of the present application; Figure 3 This is a fluorescence and afterglow photograph of a red organic room temperature phosphorescent material provided in Example 2 of the present application; Figure 4 The fluorescence emission spectrum, phosphorescence emission spectrum and phosphorescence quantum yield of the red organic room temperature phosphorescent material provided in Example 3 of the present application; Figure 5 is a phosphorescence lifetime diagram of a red organic room temperature phosphorescent material provided in Example 3 of the present application; Figure 6 This is a fluorescence and afterglow photograph of the red organic room temperature phosphorescent material provided in Example 3 of the present application. DETAILED DESCRIPTION

[0018] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0019] It should be noted that the preparation processes of the red organic room temperature phosphorescent materials in the embodiments are similar, and the only difference is the difference in the host material. In the following embodiments, the host materials are 5-methoxytetralone and 2-benzoylpyridine as examples of the preparation method, wherein the structural formulas of the host material and the guest material used in the present invention are as follows: Example 1 The preparation of the red phosphorescent emitter (NBMCy-B4) specifically includes the following steps: Under argon protection, 1,3-dimethylbarbituric acid boron fluoride complex (200 mg, 0.81 mmol) was added to a dimethylformamide solution (2 mL) containing 4-chloro-1-methyl-quinoline perchlorate (226 mg, 0.81 mmol) and triethylamine (168 μL, 1.22 mmol), and the system was heated to 50 °C and stirred for 1 hour. After the reaction, isopropyl ether (20 mL) was added to the reaction solution, and the precipitate was centrifuged and silica gel column chromatography (dichloromethane) to obtain the orange solid target product NBMCy-B4 (103 mg, yield 33%), melting point: 252 °C–253 °C.

[0020] The spectral characterization data of NBMCy-B4 are as follows: ( E )-2,2-difluoro-6,8-dimethyl-4-((1-methylquinoline-4(1 H )-(2,8-dihydro-5-(2-nitropropene)methyl)-2,8-dihydro-5-nitropropene H -2λ 4 ,3λ 3 -[1,3,2]dioxaborinano[4,5- d ]pyrimidine-5,7(6 H )-dione (NBMCy-B4). E )-2,2-Difluoro-6,8-dimethyl-4-((1-methylquinolin-4(1 H )-ylidene)methyl)-2,8-dihydro-5 H -2λ 4 ,3λ 3 -[1,3,2]dioxaborinino[4,5- d ]pyrimidine-5,7(6 H )-dione. 1 H NMR (400MHz, DMSO- d 6): δ 8.68 (d,J = 6.8 Hz, 1H), 8.48–8.37 (m, 2H), 8.22–8.11 (m, 2H),8.04 (t, J = 6.8 Hz, 1H), 7.87 (t, J = 6.8 Hz, 1H), 4.22 (s, 3H), 3.33 (s, 3H), 3.25 (s, 3H) ppm; 13 C NMR (100 MHz, DMSO- d 6): δ 180.7, 166.8, 162.1, 159.9,152.3, 149.4, 145.3, 138.3, 133.1, 127.4, 124.7, 118.5, 113.4, 92.0, 87.5,42.7, 28.5, 27.8 ppm; IR (KBr): v max 3413, 1695, 1651, 1618, 1581, 1525, 1460,1382, 1337, 1273, 1228, 1196, 1161, 1046, 962, 852, 828, 764 cm -1 ; 19 F NMR (470MHz, DMSO- d 6): δ -143.13 (s, 2F); HRMS (ESI+): m / z Calculate for C 18 H 16 BF2N3O4Na [M+Na] + 410.1094; found 410.1091.

[0021] Example 2 The preparation of red organic room temperature phosphorescent material (NBMCy-B4 / 5-methoxytetralone, 1000:3) specifically includes the following steps: Step 1: The red phosphorescent emitter (NBMCy-B4) (1.0 mg) prepared in Example 1 was dissolved in dichloromethane (2.6 mL) to a concentration of 1×10 -3 M guest mother liquor; at the same time, 5-methoxynaphthalene ketone (100 mg) was dissolved in dichloromethane (5 mL) to obtain the host mother liquor (1.14×10 -1 M); Step 2: Take 1.7 mL of the guest mother solution obtained in step 1 and mix it evenly with the host mother solution (5 mL) obtained in step 1, evaporate the solvent under reduced pressure, and then dry to obtain an orange amorphous red room temperature phosphorescent material (1000:3 molar ratio); Step 3: Heat the orange amorphous red room temperature phosphorescent material obtained in step 2 to 95 °C until the sample is completely melted, pour the sample into a mold, and slowly cool it to room temperature to obtain a red organic room temperature phosphorescent material with a similar crystal morphology (NBMCy-B4 / 5-methoxynaphthalene ketone, 1000:3).

[0022] Example 3 The preparation of red organic room temperature phosphorescent material (NBMCy-B4 / 2-benzoylpyridine, 1000:3) specifically includes the following steps: Step 1: The red phosphorescent emitter (NBMCy-B4) (1.0 mg) prepared in Example 1 was dissolved in dichloromethane (2.6 mL) to a concentration of 1×10 -3 M guest mother liquor; at the same time, 2-benzoylpyridine (104 mg) was dissolved in dichloromethane (5 mL) to obtain the host mother liquor (1.14×10 -1 M); Step 2: Take 1.7 mL of the guest mother solution obtained in step 1 and mix it evenly with the host mother solution (5 mL) obtained in step 1, evaporate the solvent under reduced pressure, and then dry to obtain an orange amorphous red room temperature phosphorescent material (1000:3 molar ratio); Step 3: Heat the orange amorphous red room temperature phosphorescent material obtained in step 2 to 45 °C until the sample is completely melted, pour the sample into a mold, and slowly cool it to room temperature to obtain a red organic room temperature phosphorescent material with a similar crystal morphology (NBMCy-B4 / 2-benzoylpyridine, 1000:3).

[0023] Example 4 Phosphorescence effect test The red organic room temperature phosphorescent materials (NBMCy-B4 / 5-methoxytetralone, 1000:3) and (NBMCy-B4 / 2-benzoylpyridine, 1000:3) prepared in Example 2 and Example 3 were subjected to performance tests. The specific process is as follows: The material sample (10 mg) was placed in a quartz sample cell, and the fluorescence emission spectrum and phosphorescence emission spectrum of the sample were tested using a luminescence spectrometer (the delay time was set to 5 ms). The luminescence quantum yield of the sample was measured using a luminescence quantum yield integrating sphere (excitation wavelength 380 nm), and the phosphorescence quantum yield was calculated based on the ratio of fluorescence to phosphorescence in the sample fluorescence spectrum.

[0024] The results are as follows Figure 1-Figure 6As shown; Figure 1 The fluorescence emission spectrum and phosphorescence emission spectrum of the red organic room temperature phosphorescent material are shown in FIG. Figure 1 It can be seen that the material Φ P =12.3% Figure 2 The phosphorescence lifetime diagram of the red organic room temperature phosphorescent material is shown in FIG. Figure 2 It can be seen that the fluorescence lifetime of this material τ P =794 ms.

[0025] Figure 3 The fluorescence and afterglow photos of red organic room temperature phosphorescent materials are shown. Figure 3 It can be seen that when excited by 365 nm ultraviolet lamp, the red afterglow emitted by the sample can last up to 8 s after the light source is turned off.

[0026] Figure 4 The fluorescence emission spectrum and phosphorescence emission spectrum of the red organic room temperature phosphorescent material are shown in FIG. Figure 4 It can be seen that the material Φ P =2.5%.

[0027] Figure 5 The phosphorescence lifetime diagram of the red organic room temperature phosphorescent material is shown in FIG. Figure 5 It can be seen that the fluorescence lifetime of this material τ P =411 ms.

[0028] Figure 6 The fluorescence and afterglow photos of red organic room temperature phosphorescent materials are shown. Figure 6 It can be seen that when excited by 365 nm ultraviolet lamp, the red afterglow emitted by the sample can last up to 4 s after the light source is turned off.

[0029] The embodiments of the present application are described above in conjunction with the accompanying drawings. Specific examples are used herein to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the core idea of ​​the present application, but the present application is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the inspiration of the present application, ordinary technicians in this field can also make many forms without departing from the scope of protection of the purpose of the present application and the claims, all of which are within the protection of the present application.

Claims

1. A red phosphorescent emitter, characterized in that: The structure of the red phosphorescent emitter is shown in Formula I: Formula I.

2. The method for preparing the red phosphorescent emitter according to claim 1, characterized in that: The following steps are involved: Under argon protection, 4-chloro-1-methyl-quinoline perchlorate and 1,3-dimethylbarbituric acid boron fluoride complex are used as raw materials, and heated in a polar solvent in the presence of an organic base to react. After the reaction, isopropyl ether is added to precipitate the product, and the crude product is centrifuged and subjected to silica gel column chromatography to obtain the red phosphorescent emitter.

3. The preparation method according to claim 2, characterized in that: The organic base is any one of triethylamine, diisopropylethylamine, triethylenediamine, tetramethylethylenediamine and 1,8-diazabicyclo[5.4.0]undec-7-ene.

4. The preparation method according to claim 2, characterized in that: The polar solvent is any one of dimethylformamide, dimethyl sulfoxide, dimethylacetamide and N-methylpyrrolidone.

5. The preparation method according to claim 2, characterized in that: The reaction temperature of the reaction is 40°C-80°C, and the reaction time of the reaction is 30 min-120 min.

6. A red organic room temperature phosphorescent material, characterized in that: The red organic room temperature phosphorescent material comprises the red phosphorescent emitter according to claim 1.

7. The red organic room temperature phosphorescent material according to claim 6, characterized in that: The red organic room temperature phosphorescent material further includes any one of 5-methoxytetralone, 4-methoxybenzophenone, 2-benzoylthiophene, 4-bromobenzophenone, 3,4-dimethoxyacetophenone, 6-methoxyindanone, 2-benzoylpyridine and 7-methoxytetralone.

8. The method for preparing the red organic room temperature phosphorescent material according to claim 7, characterized in that: The following steps are involved: Dissolving a red phosphorescent emitter and a host material in an organic solvent respectively to obtain a red phosphorescent emitter mother solution and a host mother solution respectively; The red phosphorescent emitter mother solution and the main body mother solution are mixed, concentrated and dried to obtain an amorphous red room temperature phosphorescent material; The amorphous red room temperature phosphorescent material is heated, poured into a mold after melting, and cooled to room temperature to obtain the red organic room temperature phosphorescent material.

9. The preparation method according to claim 8, characterized in that: The molar ratio of the host material to the red phosphorescent emitter is 1000:3-10000:

1.

10. The preparation method according to claim 8, characterized in that: The organic solvent includes at least one of dichloromethane, chloroform, tetrahydrofuran, dioxane, ethyl acetate, acetonitrile, methanol, ethanol, and dimethylformamide.

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