Doped red organic room temperature phosphorescent material based on red phosphorescent emitter and preparation method thereof

Abstract

The application belongs to the technical field of organic room-temperature phosphorescent material synthesis, and particularly relates to a doped red organic room-temperature phosphorescent material based on a red phosphorescent emitter and a preparation method. The structure of the red phosphorescent emitter is shown as formula I. The red phosphorescent emitter has a novel molecular structure, is easy to prepare and has stable properties. The application further provides a red organic room-temperature phosphorescent material, which has the characteristics of super-long lifetime and high brightness. Experimental data show that the red phosphorescent lifetime of the material can be up to 794 ms, and the material has a phosphorescent quantum yield of up to 12.3%.

Description

Technical Field

[0001] This application belongs to the field of organic room temperature phosphorescent material synthesis technology, specifically relating to a doped red organic room temperature phosphorescent material based on a red phosphorescent emitter and its preparation method. Background Technology

[0002] In recent years, a large number of products with long lifespans have emerged. τ P ) and high phosphorus photon yield ( Φ P Organic room-temperature phosphorescent materials (ORF) are available. However, due to the small ground-excited state band gap of red phosphorescent emitters, red phosphorescence is more susceptible to nonradiative transitions. Therefore, compared to phosphorescent materials of other colors, high-quality organic room-temperature phosphorescent materials were extremely rare before 2022 (Adv. Optical Mater. 2021, 2002197). Since 2022, with the continuous increase in research in this field, some single-component, eutectic, film, and host-guest doped materials with red room-temperature phosphorescence properties have been reported. However, according to El-sayed rules, τ P and Φ P They hinder each other. Therefore, it is necessary to obtain a combination of strengths. τ P With Gao Φ P High-performance red room-temperature phosphorescent materials remain very difficult to develop.

[0003] Currently, among the few types that simultaneously possess... τ P >100 ms and Φ P In red organic room-temperature phosphorescent materials with >5% red phosphorescence (Adv. Optical Mater. 2023, 2302482; Chem. Eng. J. 2024, 492, 152419; Nat. Commun. 2022, 13, 186; Adv. Sci. 2024, 11, 2308897), the red phosphorescent emitters are all fused-ring aromatic hydrocarbons (such as pyrene and dibenzo[g,p] fused dinaphthalene, etc.) as emitting groups. This type of emitter mainly utilizes the low band gap and the rigidity of the structure of fused-ring aromatic hydrocarbons to obtain both long band gap and long luminescence. τ P With Gao Φ P It exhibits red, room-temperature phosphorescence emission. Among these, the 2,10-bisphenoxazine-dibenzo[g,p]-naphthalene (guest) / β-estradiol (host) system shows the best performance. τ P=640 ms and Φ P =8.7% (Adv. Sci. 2024, 11, 2308897). However, the synthesis of this guest is cumbersome, and the host can be absorbed transdermally and has hormonal activity. In addition, pyrene and other fused aromatic ring guest molecules also have strong carcinogenicity.

[0004] Therefore, it is an extremely difficult task to break free from the constraints of fused aromatic ring structures through new molecular engineering design strategies, obtain easily prepared novel red phosphorescent emitters, and screen for matching host materials to surpass the performance of current red organic room temperature phosphorescent materials. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a doped red organic room temperature phosphorescent material based on a red phosphorescent emitter and its preparation method, specifically adopting the following technical solution:

[0006] In a first aspect, the present invention provides a red phosphorescent emitter (NBMCy-B4), the structure of which is shown in Formula I:

[0007] Formula I.

[0008] Secondly, the present invention also provides a method for preparing the above-mentioned red phosphorescent emitter, comprising the following steps:

[0009] Under argon protection, 4-chloro-1-methyl-quinoline perchlorate and 1,3-dimethylbarbiturate boron-fluorine complex were used as raw materials and reacted in a polar solvent in the presence of an organic base. After the reaction was completed, isopropyl ether was added to precipitate the product. The crude product was centrifuged and silica gel column chromatography was used to obtain the red phosphorescent emitter (NBMCy-B4).

[0010] 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).

[0011] As a further preferred embodiment, the solvent is any one of dimethylformamide, dimethyl sulfoxide, dimethylacetamide, and N-methylpyrrolidone.

[0012] As a further preferred embodiment, the reaction time of the above reaction is 40 ℃-80 ℃, and the reaction time is 30 min-120 min.

[0013] Thirdly, the present invention provides a red organic room temperature phosphorescent material, which includes the aforementioned red phosphorescent emitter.

[0014] As a further preferred embodiment, the aforementioned red organic room temperature phosphorescent material further includes any one of 5-methoxynaphthone, 4-methoxybenzophenone, 2-benzoylthiophene, 4-bromobenzophenone, 3,4-dimethoxyacetophenone, 6-methoxyindone, 2-benzoylpyridine, and 7-methoxynaphthone.

[0015] Fourthly, the present invention provides a method for preparing the above-mentioned red organic room-temperature phosphorescent material, comprising the following steps:

[0016] The aforementioned red phosphorescent emitter and the host material were dissolved in organic solvents to obtain a red phosphorescent emitter mother liquor and a host material mother liquor, respectively.

[0017] The red phosphorescent emitter mother liquor and the main mother liquor were mixed, concentrated and dried to obtain an amorphous red room temperature phosphorescent material.

[0018] The amorphous red room temperature phosphorescent material is heated, melted, poured into a mold, and cooled to room temperature to obtain the red organic room temperature phosphorescent material.

[0019] The host material is one of 5-methoxynaphthone, 4-methoxybenzophenone, 2-benzoylthiophene, 4-bromobenzophenone, 3,4-dimethoxyacetophenone, 6-methoxyindanone, 2-benzoylpyridine, and 7-methoxynaphthone. Most preferably, the host material is 5-methoxynaphthone. Experimental tests show that the NBMCy-B4 / 5-methoxynaphthone material has the longest phosphorescence lifetime and the highest quantum yield.

[0020] 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 observe with the naked eye; when the ratio is greater than 1000:3, the red phosphorescent emitter will aggregate, resulting in a significant reduction in phosphorescence emission intensity.

[0021] As a further preferred embodiment, the organic solvent mentioned above includes at least one of dichloromethane, chloroform, tetrahydrofuran, dioxane, ethyl acetate, acetonitrile, methanol, ethanol, and dimethylformamide.

[0022] The beneficial effects of this invention are as follows:

[0023] This invention provides a novel red phosphorescent emitter (NBMCy-B4) with a novel molecular structure, which is easy to prepare and exhibits stable properties. Furthermore, this invention provides a method for preparing a red organic room-temperature phosphorescent material. This method employs a "dual-locking" strategy through molecular engineering design. First, multiple intramolecular interactions are introduced into the guest structure to enhance molecular rigidity (first-level locking). Second, a special host capable of strong intermolecular interactions with the guest molecule is selected to enhance the energy transfer of the host-guest Dexter triplet state while suppressing nonradiative transitions (second-level locking), thereby obtaining a material with both long-lasting and stable properties. τ P With Gao Φ P A novel red organic room-temperature phosphorescent material was developed. Data from the examples show that the NBMCy-B4 / 5-methoxynaphthone (1000:3 molar ratio) red room-temperature phosphorescent material provided by this invention exhibits the best performance. τ P =794 ms and Φ P =12.3%. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] 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 this application are shown.

[0026] Figure 2 This is a phosphorescence lifetime diagram of the red organic room temperature phosphorescent material provided in Example 2 of this application;

[0027] Figure 3 The fluorescence and afterglow photographs of the red organic room-temperature phosphorescent material provided in Example 2 of this application are shown.

[0028] 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 this application are shown.

[0029] Figure 5 This is a phosphorescence lifetime diagram of the red organic room temperature phosphorescent material provided in Example 3 of this application;

[0030] Figure 6 This is a fluorescence and afterglow photograph of the red organic room temperature phosphorescent material provided in Example 3 of this application. Detailed Implementation

[0031] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0032] It should be noted that the preparation processes for the red organic room-temperature phosphorescent materials in the examples are similar, with the only difference being the host material. The following examples use 5-methoxynaphthone and 2-benzoylpyridine as host materials as examples of the preparation method. The structural formulas of the host and guest materials used in this invention are shown below:

[0033]

[0034] Example 1

[0035] The preparation of the red phosphorescent emitter (NBMCy-B4) specifically includes the following steps:

[0036] Under argon protection, 1,3-dimethylbarbiturate boron-fluoride complex (200 mg, 0.81 mmol) was added to a dimethylformamide solution (2 mL) containing 4-chloro-1-methylquinoline perchlorate (226 mg, 0.81 mmol) and triethylamine (168 μL, 1.22 mmol). The system was heated to 50 °C and stirred for 1 hour. After the reaction was complete, isopropyl ether (20 mL) was added to the reaction solution. The precipitate was separated by centrifugation and silica gel column chromatography (dichloromethane) to obtain the orange solid target product NBMCy-B4 (103 mg, yield 33%) with a melting point of 252 °C–253 °C.

[0037] The spectral characterization data of NBMCy-B4 are as follows:

[0038] ( E )-2,2-difluoro-6,8-dimethyl-4-((1-methylquinoline-4(1) H )-methylene)-2,8-dihydro-5 H -2λ 4 ,3λ 3 -[1,3,2]dioxaboronhexacyclohexane[4,5- d Pyrimidine-5,7(6) H )-Diketone (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 calcd for C 18 H 16 BF2N3O4Na [M+Na] +410.1094; found 410.1091.

[0039] Example 2

[0040] The preparation of a red organic room-temperature phosphorescent material (NBMCy-B4 / 5-methoxynaphthoquinone, 1000:3) specifically includes the following steps:

[0041] Step 1: Dissolve 1.0 mg of the red phosphorescent emitter (NBMCy-B4) prepared in Example 1 in 2.6 mL of dichloromethane to prepare a solution with a concentration of 1×10⁻⁶. -3 The guest stock solution of M; simultaneously, 5-methoxynaphthone (100 mg) was dissolved in dichloromethane (5 mL) to obtain the main stock solution (1.14 × 10⁻⁶). -1 M);

[0042] Step 2: Take 1.7 mL of the guest mother liquor obtained in Step 1 and mix it with the main mother liquor obtained in Step 1 (5 mL) evenly. Remove the solvent under reduced pressure and then dry to obtain an orange amorphous red room temperature phosphorescent material (1000:3 molar ratio).

[0043] 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 (NBMCy-B4 / 5-methoxynaphthone, 1000:3) with a similar crystalline morphology.

[0044] Example 3

[0045] The preparation of a red organic room-temperature phosphorescent material (NBMCy-B4 / 2-benzoylpyridine, 1000:3) specifically includes the following steps:

[0046] Step 1: Dissolve 1.0 mg of the red phosphorescent emitter (NBMCy-B4) prepared in Example 1 in 2.6 mL of dichloromethane to prepare a solution with a concentration of 1×10⁻⁶. -3 The guest mother liquor of M; simultaneously, 2-benzoylpyridine (104 mg) was dissolved in dichloromethane (5 mL) to obtain the main mother liquor (1.14 × 10⁻⁶ mg). -1 M);

[0047] Step 2: Take 1.7 mL of the guest mother liquor obtained in Step 1 and mix it with the main mother liquor obtained in Step 1 (5 mL) evenly. Remove the solvent under reduced pressure and then dry to obtain an orange amorphous red room temperature phosphorescent material (1000:3 molar ratio).

[0048] 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 (NBMCy-B4 / 2-benzoylpyridine, 1000:3) with a similar crystalline morphology.

[0049] Example 4

[0050] Phosphorescence effect test

[0051] The red organic room-temperature phosphorescent materials (NBMCy-B4 / 5-methoxynaphthone, 1000:3) and (NBMCy-B4 / 2-benzoylpyridine, 1000:3) prepared in Examples 2 and 3 were subjected to performance testing. The specific process is as follows:

[0052] The material sample (10 mg) was placed into a quartz sample cell, and the fluorescence emission spectrum and phosphorescence emission spectrum of the sample were tested using a luminescence spectrometer (delay time set to 5 ms). The luminescence quantum yield of the sample was measured using a luminescence quantum yield integrating sphere (excitation wavelength 380 nm). The phosphorescence quantum yield can be calculated based on the ratio of fluorescence to phosphorescence in the sample fluorescence spectrum.

[0053] The result is as follows Figures 1-6 As shown;

[0054] Figure 1 The image shows the fluorescence emission spectrum and phosphorescence emission spectrum of a red organic room-temperature phosphorescent material, and is composed of... Figure 1 It can be seen that the material Φ P =12.3%

[0055] Figure 2 The image shows the phosphorescence lifetime of a red organic room-temperature phosphorescent material, and is composed of... Figure 2 It can be seen that the fluorescence lifetime of this material is... τ P =794 ms.

[0056] Figure 3 The image shown is a fluorescence and afterglow photograph of a red organic room-temperature phosphorescent material, and it is composed of... Figure 3 It can be seen that when excited by a 365 nm ultraviolet lamp, the red afterglow emitted by the sample can last for up to 8 seconds after the light source is turned off.

[0057] Figure 4 The image shows the fluorescence emission spectrum and phosphorescence emission spectrum of a red organic room-temperature phosphorescent material, and is composed of... Figure 4 It can be seen that the material Φ P =2.5%.

[0058] Figure 5The image shows the phosphorescence lifetime of a red organic room-temperature phosphorescent material, and is composed of... Figure 5 It can be seen that the fluorescence lifetime of this material is... τ P =411 ms.

[0059] Figure 6 The image shown is a fluorescence and afterglow photograph of a red organic room-temperature phosphorescent material, and it is composed of... Figure 6 It can be seen that when excited by a 365 nm ultraviolet lamp, the red afterglow emitted by the sample can last for up to 4 seconds after the light source is turned off.

[0060] The embodiments of this application have been described above with reference to the accompanying drawings. Specific examples have been used to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the core ideas of this application. However, this application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of this application without departing from the spirit and scope of the claims, and all of these forms are within the protection scope of this 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, Includes the following steps: Under argon protection, 4-chloro-1-methyl-quinoline perchlorate and 5-acetyl-1,3-dimethylbarbiturate boron-fluorine complex were used as raw materials and the reaction was carried out in a polar solvent in the presence of an organic base. After the reaction was completed, isopropyl ether was added to precipitate the product. The crude product was centrifuged and silica gel column chromatography was used 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 is 40 ℃-80 ℃, and the reaction time is 30 min-120 min.

6. A red organic room-temperature phosphorescent material, characterized in that, The red organic room temperature phosphorescent material includes the red phosphorescent emitter as described in claim 1.

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

8. The method for preparing the red organic room-temperature phosphorescent material according to claim 7, characterized in that, Includes the following steps: The red phosphorescent emitter and the host material were dissolved in organic solvents to obtain the red phosphorescent emitter mother liquor and the host material mother liquor, respectively. The red phosphorescent emitter mother liquor and the main mother liquor were mixed, concentrated and dried to obtain an amorphous red room temperature phosphorescent material. The amorphous red room temperature phosphorescent material is heated, melted, poured into a mold, 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 main 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.

Images