A novel red light narrow-band emitting compound and a method for preparing the same

Abstract

The application belongs to the field of organic light-emitting materials, and particularly relates to a novel red light narrow-band light-emitting compound and a preparation method thereof. The compound has a structure as shown in general formula I. By introducing a benzofuran electron-donating group in a non-benzene aromatic seven-membered ring skeleton and a dicyano electron-withdrawing group in a five-membered ring, a push-pull electron structure is constructed, so that red shift of an emission spectrum is realized while the narrow-band light-emitting property is maintained. The compound can maintain a full width at half maximum (FWHM) of 28 nm when the doping concentration is 10% in an aggregated state, and CIE (0.708, 0.292), which meets the BT.2020 standard. The preparation method provided by the application has simple steps and high yield, and the prepared compound has a wide application prospect in the field of organic electroluminescent devices.

Description

Technical Field

[0001] This invention belongs to the field of organic light-emitting materials, specifically relating to a non-benzene aromatic compound with a narrow red light band and its preparation method. Background Technology

[0002] Organic light-emitting diodes (OLEDs) have attracted much attention due to their advantages such as low power consumption, flexibility, and wide color gamut, and have become a core direction of next-generation display and lighting technologies. To achieve ultra-high-definition displays (such as the BT.2020 standard), luminescent materials need to have a narrow full width at half maximum (FWHM) to meet the requirements of high color purity, with the development of red light-emitting materials being particularly crucial. However, current red organic light-emitting materials generally suffer from a wide emission spectrum, with their FWHM typically greater than 30 nm, and some multi-resonance red light-emitting materials even exceeding 40 nm (Ha JM, Hur SH, Pathak A). et al. NPG Asia Master. 2021 13 53. Li S., Ma Z., Xie W., et al.J. Am. Chem. Soc. 2026, 148 , 6766–6771.Kang J., Shin DJ, Lee JY, Adv. Optical Mater. 2025 13 (2402653.) is difficult to meet the stringent requirements of BT.2020 for red light color coordinates.

[0003] Non-benzene aromatic compounds have attracted widespread attention in recent years due to their unique charge separation characteristics and photophysical properties. Among them, the APD seven-membered ring skeleton, as an emerging conjugated system, exhibits excellent photoelectric properties. Chinese patent CN118955527A discloses a class of APD seven-membered ring derivatives, their preparation methods, and applications. Although this patent provides a method for seven-membered ring derivatization, the compounds provided by this patent failed to achieve narrow-band red light emission. Furthermore, the lack of sterically hindered substituents at the edge of the parent core led to severe molecular aggregation, limiting practical applications.

[0004] Therefore, there is an urgent need to develop a new type of red light material with a full width at half maximum (FWHM) of less than 30 nm to improve color purity and promote the further development of ultra-high-definition display technology. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a novel narrow-band red-light luminescent compound and its preparation method. While achieving a spectral redshift, it further suppresses molecular aggregation, maintaining a narrow full width at half maximum (FWHM) even in the aggregated state.

[0006] A first aspect of the present invention is to provide a red-light narrow-band luminescent compound having a structure as shown in general formula I:

[0007]

[0008] Among them, R 1 ~R 4 Each of the following is independently selected from hydrogen, deuterium, halogen, nitro, cyano, C1-C30 chain alkyl, C3-C30 cycloalkyl, C1-C10 alkoxy, C1-C10 thioalkyl, C6-C30 aryl, C6-C60 aryloxy, C3-C30 heteroaryl, C6-C30 arylamino, and C3-C30 heteroarylamino;

[0009] R 5 ~R 6 They are independently selected from hydrogen, deuterium, halogen, C1~C30 chain alkyl, C3~C30 cycloalkyl, C1~C10 alkoxy, C6~C30 aryl, C6~C60 aryloxy, C3~C30 heteroaryl, C6~C30 arylamino, and C3~C30 heteroarylamino.

[0010] Furthermore, the red-light narrow-band luminescent compound has a chemical structure as shown in general formula II:

[0011] Furthermore, the aryl group of C6 to C30 is selected from one or more of phenyl, naphthyl, anthracene, benzo[a]anthrayl, phenanthryl, fluorenyl, spirodifluorenyl, benzo[a]fluorenyl, and dibenzo[a]fluorenyl.

[0012] Furthermore, the heteroaryl group of C3 to C30 is selected from one or more of furanyl, benzofuranyl, isobenzofuranyl, dibenzofuranyl, thiophenyl, benzothiophenyl, isobenzothiophenyl, dibenzothiophenyl, pyrroleyl, indolyl, isoindolyl, benzoindolyl, and carbazoleyl.

[0013] Furthermore, the red-light narrow-band luminescent compound is selected from compounds with the following specific structures:

[0014]

[0015] A second aspect of the present invention is to provide a method for preparing the novel red-light narrow-band non-benzene aromatic compound as described above, the method comprising the following steps:

[0016] (1) Reactant A and reactant B are dissolved in a solvent and reacted in the presence of a transition metal catalyst, a base, and an additive to obtain intermediate C. The reaction formula is as follows:

[0017]

[0018] (2) Intermediate C and N-bromosuccinimide are dissolved in a solvent to react and obtain intermediate D. The reaction formula is shown below:

[0019]

[0020] (3) Intermediate D, zinc cyanide, is dissolved in a solvent and reacted under the action of a transition metal catalyst to finally obtain a red-light narrow-band luminescent compound. The reaction formula is as follows:

[0021]

[0022] Preferably, the solvent for the reaction in step (1) is one or two of tetrahydrofuran and 1,4-dioxane; the mass of the solvent is 10 to 1000 times the mass of reactant A.

[0023] Preferably, the molar ratio of reactant A to reactant B in step (1) is 1.0:1.0~5.0.

[0024] Preferably, the reaction temperature in step (1) is 70~100℃ and the reaction time is 1~2 days.

[0025] Preferably, the transition metal catalyst in step (1) is selected from one or more of palladium acetate, palladium chloride, tetra(triphenylphosphine)palladium, chloro(2-dicyclohexylphosphino-2',4',6'-triisopropyl-1,1'-biphenyl)[2-(2'-amino-1,1'-biphenyl)]palladium(II), 1,1'-bis(diphenylphosphine)ferrocene palladium dichloride, or tris(dibenzylacetone)palladium; the molar ratio of the transition metal catalyst to reactant A is 0.05~1.0:1.0.

[0026] Preferably, the additive used in step (1) is selected from one or more of the following: triphenylphosphine, tricyclohexylphosphine, tri-tert-butylphosphine, tris(o-methylphenyl)phosphine, 2-dicyclohexylphosphine-2',6'-dimethoxybiphenyl, 4,5-bis(diphenylphosphine-9,9-dimethyloxanthracene, 2-dicyclohexylphosphine-2',4',6'-triisopropylbiphenyl, 2-dicyclohexylphosphine-2',6'-diisopropoxy-1,1'-biphenyl, and 1,1'-bis(diphenylphosphine)ferrocene; the molar ratio of the additive to reactant A is 0.05~2.0:1.0.

[0027] Preferably, the base used in the reaction in step (1) is selected from one or more of sodium carbonate, sodium bicarbonate, potassium carbonate, potassium phosphate, cesium carbonate, potassium acetate, and triethylamine; the molar ratio of the base to reactant A is 1.0~10.0:1.0.

[0028] Preferably, the solvent for the reaction in step (2) is selected from one or more of tetrahydrofuran, 3-methyltetrahydrofuran, and 1,4-dioxane. The mass of the solvent is 10 to 1000 times the mass of intermediate C.

[0029] Preferably, the molar ratio of intermediate C to N-bromosuccinimide (NBS) in step (2) is 1.0:2.0~3.0.

[0030] Preferably, the reaction temperature in step (2) is room temperature, and the reaction time is 2 to 12 hours.

[0031] Preferably, step (3) is carried out in an inert atmosphere, which may be nitrogen or argon.

[0032] Preferably, the solvent for the reaction in step (3) is selected from... N,N One or more of dimethylformamide, tetrahydrofuran, and 1,4-dioxane. The mass of the solvent is 10 to 100 times the mass of intermediate D.

[0033] Preferably, the molar ratio of intermediate D to zinc cyanide in step (3) is 1.0:2.0~3.0.

[0034] Preferably, the reaction temperature in step (3) is 80~120℃. The reaction time is 1~2 days.

[0035] Preferably, the transition metal catalyst for the reaction in step (3) is selected from one or two of palladium acetate, palladium chloride, and tetra(triphenylphosphine)palladium.

[0036] The preparation method of reactant A includes the following steps, and the reaction formula is as follows:

[0037]

[0038] a. Compound 1 and compound 2 were dissolved in tetrahydrofuran and water (tetrahydrofuran to water ratio 10:1) under an inert atmosphere in the presence of tetra(triphenylphosphine)palladium and potassium carbonate to prepare intermediate 3. Compound 1 and compound 2 can be obtained from the literature (Zhang W., Sun J., Yang D., ...). et al.Adv. Synth. Catal. 2024, 366 , 2710.Saxena P., Maida N., Kapur. M., Chem. Commun. Prepared by the method described in ,2019, 55, 11187–11190.

[0039] The molar ratio of compound 1 to compound 2 is 1.0:1.0~1.5; the molar ratio of compound 1 to tetra(triphenylphosphine)palladium is 1.0:0.02~2.0; the molar ratio of compound 1 to potassium carbonate is 1.0:0.5~4.0; the mass of tetrahydrofuran and water is 10~1000 times that of compound 1; the reaction temperature is 40~70℃; the reaction time is 2~24 h; and the inert atmosphere can be nitrogen or argon.

[0040] b. Dissolve intermediate 3 in tetrahydrofuran, add N-bromosuccinimide (NBS) and react to obtain intermediate 4.

[0041] The molar ratio of intermediate 3 to N-bromosuccinimide (NBS) is 1.0:2.0~4.0; the mass of tetrahydrofuran is 10~1000 times that of intermediate 3; the reaction temperature is room temperature; and the reaction time is 24~48 h.

[0042] c. Dissolve intermediate 4 in diethyl ether, and under an inert atmosphere, add trimethyl borate in the presence of n-butyllithium to react and obtain reactant A.

[0043] The molar ratio of intermediate 4 to n-butyllithium is 1.0:2.0~4.0; the mass of diethyl ether is 10~1000 times that of intermediate 4; the reaction temperature is -78℃~25℃; and the reaction time is 2~24h.

[0044] The preparation method of reactant B includes the following steps, and the reaction formula is as follows:

[0045]

[0046] Compound 5, R 1 -B(OH)2, R 3 -B(OH)2 was dissolved in tetrahydrofuran and water (in a ratio of 10:1) under an inert atmosphere in the presence of palladium acetate, 2-biscyclohexylphosphine-2',6'-dimethoxybiphenyl (Sphos), and potassium phosphate to prepare reactant B.

[0047] Among them, compound 5 and R 1 -B(OH)2 and R 3 The molar ratio of -B(OH)2 is 1.0:1.0~2.0.

[0048] The molar ratio of compound 5 to palladium acetate is 1.0:0.02–2.0; the molar ratio of compound 5 to potassium phosphate is 1.0:0.5–4.0; the mass ratio of tetrahydrofuran and water is 10–1000 times that of compound 5; the reaction temperature is 70–100 °C; the reaction time is 24–48 h; and the inert atmosphere can be nitrogen or argon. Compound 5 can be prepared by methods described in the literature. (Fei Y., Fu Y., Bai X.) et al.J. Am. Chem. Soc. 2021 143 , 2353-2360.

[0049] Compared with the prior art, the present invention has the following beneficial effects:

[0050] 1. The novel narrow-band non-benzene aromatic compound preparation method proposed in this invention is simple and easy to implement. The bromine atom, acting as a linking unit, can rapidly introduce diverse substituents, effectively regulating intermolecular aggregation. Furthermore, the introduction of benzofuran as a synthetic building block into the seven-membered ring, utilizing its electron-donating properties and the relatively weak aromaticity of the furan ring, reduces interference with the vibrational coupling of the molecular skeleton, thereby achieving a spectral redshift while maintaining a narrow full width at half maximum (FWHM).

[0051] 2. Compared with monocyclic heterocyclic compounds such as furan, thiophene, and pyrrole, benzofuran has the dual advantages of a rigid fused ring skeleton and weak aromaticity, and it causes less disturbance to the electronic structure of the parent nucleus, thus effectively suppressing spectral broadening.

[0052] 3. The novel narrow-band non-benzene aromatic compound provided by this invention exhibits narrow-band red light emission characteristics. In the aggregated state, even with a doping concentration of 10%, it still maintains a full width at half maximum (FWHM) of 28 nm, and its CIE coordinates (0.708, 0.292) meet the BT.2020 standard. This invention achieves a spectral redshift while further suppressing molecular aggregation, maintaining a narrow FWHM even in the aggregated state. This characteristic of maintaining narrow red light emission even in the aggregated state gives it broad application potential in the field of organic optoelectronic materials, especially suitable for the development of organic electroluminescent devices. Attached Figure Description

[0053] Figure 1 The absorption and fluorescence spectra of BFAPD-1 prepared in Example 1 are shown below;

[0054] Figure 2 The absorption and fluorescence spectra of BFAPD-2 prepared in Example 2 are shown below;

[0055] Figure 3 The fluorescence spectrum of the BFAPD-2 doped thin film prepared in Example 2 is shown below.

[0056] Figure 4The fluorescence spectrum of APDBt prepared in Comparative Example 1;

[0057] Figure 5 The fluorescence spectrum of BFCN-1 prepared in Comparative Example 2 is shown.

[0058] Figure 6 The fluorescence spectrum of BFCN-2 prepared in Comparative Example 3 is shown.

[0059] Figure 7 The fluorescence spectrum of BF-1 prepared in Comparative Example 4 is shown.

[0060] Figure 8 The fluorescence spectrum of BF-2 prepared in Comparative Example 5 is shown. Detailed Implementation

[0061] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that these embodiments are only for helping to better understand the content of the present invention and should not be construed as limiting the scope of the present invention.

[0062] Example 1:

[0063] Synthesis of Intermediate 3: Under argon protection, benzofuran-3-boronic acid (1.5 g, 9.26 mmol), 3-bromo-1-benzofuran (2.01 g, 10.2 mmol), tetra(triphenylphosphine)palladium (104 mg, 0.09 mmol), and potassium carbonate (3.84 g, 27.8 mmol) were added sequentially to a 200 mL Schlenk flask, followed by tetrahydrofuran (100 mL) and water (10 mL). The mixture was stirred and heated at 75 °C for 18 hours. After the reaction was complete, the system was cooled to room temperature, the reaction was quenched with 50 mL of water, and extracted with dichloromethane (100 mL × 3). The combined organic phases were dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure to obtain the crude product. The crude product was filtered through diatomaceous earth, washed with dichloromethane, concentrated again under reduced pressure, and finally recrystallized from dichloromethane / methanol to give 2.15 g of white solid, yield 99%. 1 H NMR (400 MHz, Chloroform- d ) δ 8.00 (s, 2H), 7.75 (d, J = 7.7 Hz, 2H), 7.60 (d, J = 8.1 Hz, 2H), 7.40 (t, J = 7.7 Hz, 2H), 7.34(t, J = 7.5 Hz, 2H). 13C NMR (101 MHz, Chloroform-d) δ 155.58, 141.76, 126.71, 125.06, 123.23, 120.71, 112.56, 111.97.

[0064] Synthesis of Intermediate 4: Intermediate 3 (1.00 g, 4.27 mmol) was added to a 100 mL single-necked flask in air, followed by tetrahydrofuran (40 mL). N-bromosuccinimide (NBS, 2.28 g, 12.8 mmol) was then slowly added with stirring, and the mixture was stirred at room temperature for 24 hours. After the reaction was complete, 20 mL of water was added to quench the reaction, and the mixture was extracted with dichloromethane (50 mL × 3). The combined organic phases were dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure to obtain the crude product. The crude product was purified by column chromatography (eluent: petroleum ether), and finally recrystallized from dichloromethane / methanol to give 1.35 g of a white solid, 99% yield. 1 H NMR (400 MHz, Chloroform- d ) δ 7.56 (t, J = 8.2 Hz, 2H), 7.41 (t,2H), 7.35 (d, 2H), 7.28 (s, 2H). 13 C NMR (101 MHz, Chloroform- d ) δ 155.75,128.47, 128.11, 125.00, 123.70, 120.26, 111.44, 111.38.

[0065] Synthesis of reactant A: Under argon protection, intermediate 4 (2.62 g, 6.68 mmol) and diethyl ether (50 mL) were added sequentially to a 200 mL Schlenk flask. Then, n-butyllithium (10.7 mL, 26.7 mmol, 2.5 min hexane) was slowly added dropwise at 0 °C, followed by stirring at 0 °C for 2 hours. The reaction mixture was then cooled to -78 °C, and trimethyl borate (2.8 g, 26.7 mmol) was added, followed by stirring for 1 hour. After warming to room temperature, hydrochloric acid (13.4 mL, 2 M) was added, followed by stirring for 2 hours. After the reaction was complete, potassium hydroxide (13.4 mL, 2 M) was added to quench the reaction. The reaction mixture was transferred to a separatory funnel and extracted three times with potassium hydroxide (10 mL × 3, 2 M). The aqueous phases were combined, and hydrochloric acid was added dropwise until the solution became acidic, precipitating a solid. The solid was filtered to give 1.4 g of a white solid, with a yield of 65%. 1H NMR (400 MHz, DMSO-d6) δ 8.07 (d, J = 7.9 Hz, 2H), 7.72 (d, J = 8.2 Hz, 2H), 7.47 (t, J = 7.7 Hz, 2H), 7.39 (t, J = 7.5 Hz, 2H). 13 C NMR (101 MHz, DMSO-d6) δ 156.71, 126.07, 125.74, 122.73, 122.38, 112.08.

[0066] Synthesis of reactant B-1: Under argon protection, compound 5 (6.00 g, 15.8 mmol), 3,5-di-tert-butylphenylboronic acid (11.1 g, 47.3 mmol), tetrakis(triphenylphosphine)palladium (185 mg, 0.158 mmol), and potassium carbonate (6.55 g, 47.4 mmol) were added sequentially to a 200 mL Schlenk flask, followed by tetrahydrofuran (100 mL) and water (10 mL). The mixture was stirred and heated at 75 °C for 18 hours. After the reaction was complete, the system was cooled to room temperature, quenched with 100 mL of water, and extracted with dichloromethane (100 mL × 3). The combined organic phases were dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure to obtain the crude product. The crude product was purified by column chromatography (eluent: petroleum ether / dichloromethane = 10:1), and finally recrystallized from dichloromethane / petroleum ether to give 5.45 g of white solid, with a yield of 58%. 1 H NMR (400 MHz, Chloroform-d) δ 7.67 (s, 2H),7.45 (t, J = 1.8 Hz, 2H), 7.39 (d, J = 1.8 Hz, 4H), 3.48 (s, 4H), 1.40 (s, 36H). 13 C NMR (101 MHz, Chloroform- d ) δ 151.19, 143.10, 142.53, 138.53, 135.64,132.41, 126.56, 124.08, 122.83, 121.64, 35.17, 31.69, 30.63.

[0067] Synthesis of intermediate C-1: Under argon protection, reactant B-1 (600 mg, 1.00 mmol), reactant A (322 mg, 1.00 mmol), chloro(2-dicyclohexylphosphino-2',4',6'-triisopropyl-1,1'-biphenyl)[2-(2'-amino-1,1'-biphenyl)]palladium(II) (Xphos Pd G2, 78.7 mg, 0.100 mmol), and potassium phosphate (637 mg, 3.00 mmol) were added sequentially to a 200 mL Schlenk flask. Tetrahydrofuran (30 mL) and water (60 mL) were then added, and the mixture was stirred and heated at 75 °C for 4 hours. After the reaction was complete, 40 mL of water was added to the system, and the mixture was extracted with dichloromethane (50 mL × 3). The combined organic phases were dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure to obtain the crude product. The crude product was purified by column chromatography (eluent: petroleum ether / dichloromethane = 10:1), and finally recrystallized from dichloromethane / methanol to give 364 mg of red solid, with a yield of 48%. 1 HNMR (400 MHz, Chloroform- d ) δ 8.99 (s, 2H), 8.50 (d, J = 7.9 Hz, 2H), 7.85 –7.78 (m, 6H), 7.75 (d, J = 8.1 Hz, 2H), 7.63 (s, J = 2.1 Hz, 2H), 7.52 (t, J = 7.6Hz, 2H), 7.45 (t, J = 7.5 Hz, 2H), 1.50 (s, 36H). 13 C NMR (101 MHz, Chloroform- d )δ 155.12, 153.32, 151.44, 140.82, 139.50, 133.82, 127.55, 127.29, 127.25,126.40, 124.85, 123.50, 123.37, 122.93, 122.24, 111.84, 35.28, 31.81, 29.87.HRMS (MALDI) m / z Calculated for C 56 H 54 O2 + , 758.4118; Found: 758.4122 [M] +Error: 0.53 ppm.

[0068] Synthesis of intermediate D-1: Intermediate C-1 (16.0 mg, 0.021 mmol) and tetrahydrofuran (10 mL) were added to a 50 mL single-necked tube, followed by the slow addition of N-bromosuccinimide (NBS, 8.25 mg, 0.046 mmol). The mixture was stirred at room temperature for 4 hours. After the reaction was complete, 10 mL of water was added to quench the reaction, and the mixture was extracted with dichloromethane (20 mL × 3). The organic phases were combined, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure to obtain the crude product. The crude product was purified by column chromatography (eluent: petroleum ether / dichloromethane = 10:1), and recrystallized from dichloromethane / methanol to give 19.0 mg of purple solid, with a yield of 98%. 1 H NMR (400MHz, Chloroform- d ) δ 8.88 (s, 2H), 8.50 (d, J = 8.0 Hz, 2H), 7.72 (d, J = 8.2 Hz, 2H), 7.62 (s, 2H), 7.56 – 7.51 (m, 6H), 7.44 (t, J = 7.5 Hz, 2H), 1.46 (s, 36H). 13 C NMR (101 MHz, Chloroform- d ) δ 155.18, 152.76, 150.24, 142.13, 137.78,128.63, 127.11, 127.02, 126.98, 125.56, 125.14, 123.46, 123.10, 122.05,119.24, 113.10, 111.92, 35.25, 31.75, 29.86. HRMS (MALDI) m / z : Calcd. forC 56 H 52 Br2O2 + , 914.2329; Found: 914.2326 [M] + Error: -0.33 ppm.

[0069] Synthesis of compound BFAPD-1: Under argon protection, intermediate D-1 (15.0 mg, 0.016 mmol), zinc cyanide (4.58 mg, 0.039 mmol), tetrakis(triphenylphosphine)palladium (2.31 mg, 0.002 mmol), and DMF (5 mL) were added sequentially to a 50 mL Schlenk flask, and the mixture was stirred at 120 °C for 24 h. After the reaction was complete, the system was cooled to room temperature, filtered through diatomaceous earth, washed with dichloromethane, and concentrated under reduced pressure to obtain the crude product. The crude product was purified by column chromatography (eluent: petroleum ether / dichloromethane = 10:3), and then recrystallized from dichloromethane / methanol to give 10.0 mg of a blue-violet solid, with a yield of 77%. 1 H NMR (400MHz, Chloroform- d ) δ 9.20 (s, 2H), 8.65 (d, J = 8.1 Hz, 2H), 7.84 (d, J = 8.3 Hz,2H), 7.73 (s, 2H), 7.70 (s, 4H), 7.66 (d, J = 8.0 Hz, 2H), 7.54 (t, J = 7.8 Hz, 2H), 1.50 (s, 36H). 13 C NMR (101 MHz, Chloroform- d ) δ 155.24, 153.10, 151.25,146.33, 136.74, 130.24, 128.60, 127.26, 126.13, 125.62, 125.16, 124.94,124.12, 123.69, 123.53, 122.88, 116.40, 114.90, 113.12, 112.16, 35.33, 31.69,29.87. HRMS (MALDI) m / z Calculated for C 58 H 52 N2O2 + , 808.4023; Found: 808.4023[M] + Error: 0 ppm.

[0070] Example 2:

[0071]

[0072] The synthesis method of reactant A is the same as that in Example 1.

[0073] Synthesis of reactant B-2: Under argon protection, compound 5 (5.00 g, 13.1 mmol), 2,4,6-trimethylphenylboronic acid (4.72 g, 28.8 mmol), tris(dibenzylacetone)dipalladium (600 mg, 0.655 mmol), tri-tert-butylphosphine (265 mg, 1.31 mmol), and potassium carbonate (5.42 g, 39.3 mmol) were added sequentially to a 200 mL Schlenk flask, followed by 1,4-dioxane (100 mL) and water (10 mL). The mixture was stirred and heated at 100 °C for 24 h. After the reaction was complete, the system was cooled to room temperature, the reaction was quenched with 100 mL of water, and extracted with dichloromethane (100 mL × 3). The combined organic phases were dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure to obtain the crude product. The crude product was purified by column chromatography (eluent: petroleum ether / dichloromethane = 10:1) to give 2.03 g of white solid, yield 48%. 1 H NMR (400 MHz, Chloroform- d ) δ 7.35 (s,2H), 6.96 (s, 4H), 2.91 (s, 4H), 2.34 (s, 6H), 2.01 (s, 12H). 13 C NMR (101 MHz, Chloroform- d ) δ 143.77, 142.36, 137.35, 135.84, 135.46, 134.33, 132.75,128.39, 126.39, 124.34, 29.52, 21.24, 20.53.

[0074] Synthesis of intermediate C-2: Under argon protection, reactant B-2 (800 mg, 2.49 mmol), reactant A (1.14 g, 2.49 mmol), chloro(2-dicyclohexylphosphino-2',4',6'-triisopropyl-1,1'-biphenyl)[2-(2'-amino-1,1'-biphenyl)]palladium(II) (Xphos Pd G2, 197 mg, 0.249 mmol), and potassium phosphate (1.59 g, 7.47 mmol) were added sequentially to a 200 mL Schlenk flask, followed by tetrahydrofuran (40 mL) and water (80 mL). The mixture was stirred and heated at 75 °C for 4 hours. After the reaction was complete, 40 mL of water was added to the system, and the mixture was extracted with dichloromethane (50 mL × 3). The combined organic phases were dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure to obtain the crude product. The crude product was purified by column chromatography (eluent: petroleum ether / dichloromethane = 10:1), and finally recrystallized from dichloromethane / methanol to give 866 mg of red solid, with a yield of 52%. 1 HNMR (400 MHz, Chloroform- d ) δ 8.67 (s, 2H), 8.47 (d, J = 7.9 Hz, 2H), 7.68 (d, J = 8.1 Hz, 2H), 7.50 (t, J = 7.8 Hz, 2H), 7.43 (t, J = 7.5 Hz, 2H), 7.23 (s, 2H), 7.10 (s, 4H), 2.45 (s, 6H), 2.13 (s, 12H). 13 C NMR (101 MHz, Chloroform- d ) δ155.08, 153.26, 139.00, 137.46, 136.62, 135.71, 128.38, 127.55, 127.15,126.76, 126.35, 124.38, 123.65, 123.32, 122.89, 111.77, 111.72, 29.86, 21.35,21.23. HRMS (MALDI) m / z Calculated for C 46 H 34 O2 + , 618.2553; Found: 618.2554[M] +Error: 0.16 ppm.

[0075] Synthesis of intermediate D-2: Intermediate C-2 (10.0 mg, 0.015 mmol) and tetrahydrofuran (10 mL) were added to a 50 mL single-necked tube, followed by the slow addition of N-bromosuccinimide (NBS, 5.34 mg, 0.030 mmol). The mixture was stirred at room temperature for 4 hours. After the reaction was complete, 10 mL of water was added to quench the reaction, and the mixture was extracted with dichloromethane (20 mL × 3). The organic phases were combined, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure to obtain the crude product. The crude product was purified by column chromatography (eluent: petroleum ether / dichloromethane = 10:1), and recrystallized from dichloromethane / methanol to give 11.4 mg of purple solid, with a yield of 98%. 1 H NMR (400MHz, Chloroform- d δ 8.69 (s, 2H), 8.50 (d, J = 7.8 Hz, 2H), 7.70 (d, J = 8.1 Hz, 2H), 7.53 (t, J = 7.2 Hz, 2H), 7.45 (d, J = 7.2 Hz, 2H), 7.10 (s, 4H), 2.47 (s, 6H), 2.07 (s, 12H). 13 C NMR (101 MHz, Chloroform- d ) δ 155.19, 152.75, 139.64,137.80, 136.58, 135.29, 129.51, 128.20, 127.86, 127.16, 127.01, 125.58,125.09, 123.43, 123.14, 123.06, 118.51, 113.07, 111.89, 29.87, 21.47, 21.19.HRMS (MALDI) m / z Calculated for C 46 H 32 Br2O2 + , 774.0764; Found: 774.0783[M] + Error: 2.45 ppm.

[0076] Synthesis of compound BFAPD-2: Under argon protection, intermediate D-2 (11.4 mg, 0.015 mmol), zinc cyanide (3.99 mg, 0.034 mmol), tetrakis(triphenylphosphine)palladium (2.31 mg, 0.002 mmol), and DMF (5 mL) were added sequentially to a 50 mL Schlenk flask, and the mixture was stirred at 120 °C for 24 h. After the reaction was complete, the system was cooled to room temperature, filtered through diatomaceous earth, washed with dichloromethane, and concentrated under reduced pressure to obtain the crude product. The crude product was purified by column chromatography (eluent: petroleum ether / dichloromethane = 10:3), and then recrystallized from dichloromethane / methanol to give 8.0 mg of a blue-violet solid, with a yield of 80%. 1 H NMR (400MHz, Chloroform- d ) δ 9.06 (s, 2H), 8.68 (d, J = 8.0 Hz, 2H), 7.82 (d, J = 8.3 Hz, 2H), 7.68 (t, J = 7.7 Hz, 2H), 7.56 (t, J = 7.6 Hz, 2H), 7.16 (s, 4H), 2.47 (s, 6H), 2.10 (s, 12H). 13 C NMR (101 MHz, Chloroform- d ) δ 155.55, 153.40, 144.96,139.01, 136.16, 133.70, 131.08, 129.07, 128.91, 128.73, 126.43, 125.35,124.88, 123.85, 123.77, 123.40, 116.99, 113.64, 112.36, 111.40, 29.86, 21.53,21.01. HRMS (MALDI) m / z Calculated for C 48 H 32 N2O2 + , 668.2458; Found: 668.2457[M] + Error: -0.15 ppm.

[0077]

[0078] Figure 3The image shows the thin film spectrum of BFAPD-2 in the aggregated state with a doping concentration of 10%, where FWHM = 28 nm.

[0079] 2CNAPD refers to the references Liu P., Tang, XY, Wang XY. et al.Sci. China Chem. The compounds reported in , 2023, 66, 3506–3510.

[0080] Comparative Example 1

[0081]

[0082] Name it APDBt.

[0083] Preparation method: The APDBt in this embodiment is roughly the same as that in synthesis embodiment 1, except for the following two reaction steps, which finally yield APDBt. 1 H NMR (400 MHz, Chloroform- d ) δ 8.28 (s, 4H), 7.69 (t, J = 1.8 Hz, 2H), 7.62 (d, J = 1.8 Hz, 4H), 7.55 (dd, J = 8.7, 3.7 Hz, 2H), 1.46 (s, 36H). 13 CNMR (101 MHz, Chloroform- d ) δ 151.26, 146.80, 142.21, 139.20, 136.55, 131.71,131.21, 126.71, 126.20, 124.85, 124.07, 115.13, 111.54, 35.29, 31.65. HRMS(MALDI) m / z: Calcd. for C 46 H 48 N2 + , 628.3821; Found: 628.3814[M] + Error: -1.11ppm.

[0084] Synthesis of intermediate C-3: Under argon protection, a THF solution of 1,3-butadiene (1.5 mL, 3.00 mmol, 2 M) was mixed with a THF solution of 9-boronbicyclo[3.3.1]nonane (9-BBN) (12 mL, 6.00 mmol, 0.5 M) and stirred at room temperature for 24 hours. The reaction mixture was then transferred to a mixture containing B-1 (1.60 g, 2.72 mmol), palladium acetate (122 mg, 0.544 mmol), 2-dicyclohexylphosphine-2',6'-dimethoxybiphenyl (Sphos, 447 mg, 1.09 mmol), potassium phosphate (1.73 g, 8.16 mmol), tetrahydrofuran (80 mL), and water (10 mL), and stirred at 70 °C for another 24 hours. After the reaction was complete, the product was extracted three times with dichloromethane (50 mL × 3). The organic phases were combined, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure to obtain the crude product. The crude product was purified by column chromatography (eluent: petroleum ether), and then recrystallized from dichloromethane / methanol to give 300 mg of white solid, with a yield of 19%. 1 H NMR (400 MHz, Chloroform- d ) δ 7.45 (d, J = 1.8 Hz, 2H), 7.41(d, J = 1.8 Hz, 1H), 7.27 (s, 2H), 3.48 (s, 2H), 3.28 (s, 2H), 2.18 – 2.10 (m,2H), 1.40 (s, 18H).

[0085] Synthesis of intermediate D-3: Intermediate C-3 (300 mg, 0.513 mmol), potassium hydroxide (288 mg, 5.13 mmol), and toluene (10 mL) were added to a 100 mL single-necked flask. 2,3-dichloro-5,6-dicyanobenzoquinone (DDQ, 582 mg, 2.56 mmol) was added with stirring at room temperature, followed by heating to 80 °C for 4 hours. After the reaction was complete, the mixture was filtered through diatomaceous earth, concentrated under reduced pressure, and toluene (10 mL) was added. Potassium tert-butoxide (233 mg, 1.03 mmol) and DDQ (576 mg, 5.13 mmol) were then added, and the mixture was heated again at 80 °C for 4 hours. After the reaction was complete, the mixture was filtered through diatomaceous earth, concentrated under reduced pressure, and the crude product was purified by column chromatography (eluent: petroleum ether). Recrystallization from dichloromethane / methanol yielded 180 mg of a red solid, with a yield of 60%. 1 H NMR (400 MHz, Chloroform- d) δ 8.10 (s, 2H), 8.04 (s, 2H), 7.89 (dd, J = 8.8, 3.8Hz, 2H), 7.79 (d, J = 1.8 Hz, 4H), 7.58 (t, J = 1.8 Hz, 2H), 6.99 (dd, J = 8.8, 3.6Hz, 2H), 1.47 (s, 36H).

[0086]

[0087] Figure 4 The fluorescence spectrum of APDBt prepared in Comparative Example 1 is shown in the figure. It can be seen from the figure that although APDBt achieves narrow-band emission, its maximum emission wavelength of 584 nm is located in the orange-red light region, which is not conducive to the extraction of the three primary colors of red, green and blue in OLED. This indicates that the benzofuran unit is a necessary condition for achieving narrow-band red light emission.

[0088] Comparative Example 2

[0089]

[0090] It was named BFCN-1.

[0091] Synthesis of BFCN-1: The synthesis process in this embodiment is largely the same as that in Synthesis Example 1, except that after obtaining intermediate C-1, the amount of N-bromosuccinimide was changed from 2.2 equivalents to 1.0 equivalents. The target compound BFCN-1 was finally obtained. 1 H NMR (400 MHz, Chloroform- d ) δ 9.10 (s, 1H), 9.03 (s, 1H), 8.55 (t, J = 7.9,5.9 Hz, 2H), 8.34 (s, 1H), 7.81 – 7.75 (m, 4H), 7.71 – 7.67 (m, 4H), 7.61 –7.56 (m, 2H), 7.51 – 7.46 (m, 2H), 1.50 (d, J = 2.2 Hz, 36H). HRMS (MALDI) m / z:Calcd. for C 57 H 53 NO2 + , 783.4071; Found: 783.4069[M] + Error: -0.26 ppm.

[0092] Figure 5 The fluorescence spectrum of BFCN-1 prepared in Comparative Example 2 is shown in the figure. It can be seen from the figure that the introduction of monocyano groups will significantly enhance the shoulder peak of the spectrum, resulting in a significant broadening of the full width at half maximum (FWHM), which is not conducive to improving color purity.

[0093] Comparative Example 3

[0094]

[0095] Named BFCN-2

[0096] Synthesis of BFCN-2: The synthesis process in this embodiment is largely the same as that in Synthesis Example 2, except that after obtaining intermediate C-2, the amount of N-bromosuccinimide was changed from 2.0 equivalents to 1.0 equivalents. The target compound BFCN-2 was finally obtained. 1 H NMR (400 MHz, Chloroform- d ) δ 8.85 (s, 2H), 8.55 (t, J = 7.0 Hz, 2H), 7.83(s, 1H), 7.74 (d, J = 8.2 Hz, 2H), 7.57 (t, J = 7.6 Hz, 2H), 7.48 (t, J = 7.6 Hz, 2H), 7.13 (d, J = 11.0 Hz, 4H), 2.46 (s, 6H), 2.11 (d, J = 7.6 Hz, 12H). HRMS(MALDI) m / z: Calcd. for C 47 H 33 NO2 + , 643.2506; Found: 643.2507 [M] + Error: 0.16ppm.

[0097] Figure 6 The fluorescence spectrum of BFCN-2 prepared in Comparative Example 3 is shown in the figure. It can be seen from the figure that the introduction of monocyano groups will significantly enhance the shoulder peak of the spectrum, resulting in a significant broadening of the full width at half maximum (FWHM), which is not conducive to improving color purity.

[0098] Comparative Example 4

[0099]

[0100] Named BF-1

[0101] Synthesis of BF-1: The synthesis process of this embodiment is to synthesize the intermediate product C-1 of Example 1.

[0102] Figure 7 The fluorescence spectrum of BF-1 prepared in Comparative Example 4 shows that it exhibits broad-band emission with a full width at half maximum (FWHM) of 81 nm in the absence of cyano group introduction.

[0103] Comparative Example 5

[0104]

[0105] Named BF-2

[0106] Synthesis of BF-2: The synthesis process of this embodiment is to synthesize the intermediate product C-2 of Example 2.

[0107] Figure 8 The fluorescence spectrum of BF-2 prepared in Comparative Example 5 shows that it exhibits broad-band emission with a full width at half maximum (FWHM) of 82 nm in the absence of cyano group introduction.

[0108] from Figures 5-8 It can be seen that the spectrum is significantly broadened when no cyano group is introduced or when a monocyano group is introduced, indicating the necessity of the dicyano group.

[0109] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several modifications and improvements can be made without departing from the inventive concept, and these all fall within the protection scope of the present invention.

Claims

1. A red-light narrow-band luminescent compound, characterized in that, It has a chemical structure as shown in general formula I: Among them, R 1 ~R 4 Each of the following is independently selected from hydrogen, deuterium, halogen, nitro, cyano, C1-C30 chain alkyl, C3-C30 cycloalkyl, C1-C10 alkoxy, C1-C10 thioalkyl, C6-C30 aryl, C6-C60 aryloxy, C3-C30 heteroaryl, C6-C30 arylamino, and C3-C30 heteroarylamino; R 5 ~R 6 They are independently selected from hydrogen, deuterium, halogen, C1~C30 chain alkyl, C3~C30 cycloalkyl, C1~C10 alkoxy, C6~C30 aryl, C6~C60 aryloxy, C3~C30 heteroaryl, C6~C30 arylamino, and C3~C30 heteroarylamino.

2. The red-light narrow-band luminescent compound according to claim 1, characterized in that, It has a chemical structure as shown in general formula II: 。 3. The red-light narrow-band luminescent compound according to claim 1, characterized in that, The aryl group of C6 to C30 is selected from one or more of phenyl, naphthyl, anthracene, benzo[a]anthrayl, phenanthryl, fluorenyl, spirodifluorenyl, benzo[a]fluorenyl, and dibenzo[a]fluorenyl.

4. The red-light narrow-band luminescent compound according to claim 1, characterized in that, The heteroaryl group of C3 to C30 is selected from one or more of furanyl, benzofuranyl, isobenzofuranyl, dibenzofuranyl, thiophenyl, benzothiophenyl, isobenzothiophenyl, dibenzothiophenyl, pyrroleyl, indolyl, isoindolyl, benzoindolyl, and carbazoleyl.

5. The red-light narrow-band luminescent compound according to claim 1, characterized in that, The red-light narrow-band luminescent compound is selected from compounds with the following specific structures: 。 6. The method for preparing the red-light narrow-band luminescent compound according to any one of claims 1 to 5, characterized in that, The preparation method of the compound of formula I includes the following steps: (1) Reactants A and B are dissolved in a solvent and reacted in the presence of a transition metal catalyst, a base, and an additive to obtain intermediate C. The reaction formula is as follows: (2) Intermediate C and N-bromosuccinimide are dissolved in a solvent to react and obtain intermediate D. The reaction formula is shown below: (3) Intermediate D, zinc cyanide, is dissolved in a solvent and reacted under the action of a transition metal catalyst to finally obtain a red-light narrow-band luminescent compound. The reaction formula is as follows: 。 7. The preparation method according to claim 6, characterized in that, In step (1), the molar ratio of reactant A to reactant B is 1.0:1.0~5.0; the reaction temperature is 70~100℃, the reaction time is 1~2 days, and the reaction is carried out in an inert atmosphere, which is selected from nitrogen or argon.

8. The preparation method according to claim 6, characterized in that, The transition metal catalyst for the reaction in step (1) is selected from one or more of palladium acetate, palladium chloride, tetra(triphenylphosphine)palladium, chloro(2-dicyclohexylphosphino-2',4',6'-triisopropyl-1,1'-biphenyl)[2-(2'-amino-1,1'-biphenyl)]palladium(II), 1,1'-bis(diphenylphosphine)ferrocene palladium dichloride, or tris(dibenzylideneacetone)palladium. The additives used in the reaction are selected from one or more of the following: triphenylphosphine, tricyclohexylphosphine, tri-tert-butylphosphine, tris(o-methylphenyl)phosphine, 2-dicyclohexylphosphine-2',6'-dimethoxybiphenyl, 4,5-bis(diphenylphosphine)-9,9-dimethyloxanthracene, 2-dicyclohexylphosphine-2',4',6'-triisopropylbiphenyl, 2-dicyclohexylphosphine-2',6'-diisopropoxy-1,1'-biphenyl, and 1,1'-bis(diphenylphosphine)ferrocene. The base used in the reaction is selected from one or more of sodium carbonate, sodium bicarbonate, potassium carbonate, potassium phosphate, cesium carbonate, potassium acetate, and triethylamine. The solvent for the reaction is selected from one or two of tetrahydrofuran and 1,4-dioxane.

9. The preparation method according to claim 6, characterized in that, In step (2), the molar ratio of intermediate C to N-bromosuccinimide is 1.0:2.0~3.0; the reaction temperature is room temperature and the reaction time is 2~12 h; the solvent for the reaction is one or more of tetrahydrofuran, 3-methyltetrahydrofuran, and 1,4-dioxane.

10. The preparation method according to claim 6, characterized in that, In step (3), the molar ratio of intermediate D to zinc cyanide is 1.0:2.0~3.0; the reaction temperature is 80~120℃, the reaction time is 1~2 days, and the reaction is carried out in an inert atmosphere, which is selected from nitrogen or argon. The transition metal catalyst for the reaction is selected from one or two of palladium acetate, palladium chloride, and tetra(triphenylphosphine)palladium; The solvent for the reaction is selected from N,N One or more of dimethylformamide, tetrahydrofuran, and 1,4-dioxane.

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