Carbonyl nitrogen type fluorescent material based on benzopentacyclo / heptacyclo structure and preparation method thereof

Abstract

The present application relates to fluorescent material technical field, especially based on benzopentacyclic / septacyclic structure's carbonyl nitrogen type fluorescent material and its preparation method, the present application provides the preparation method with carbazole as raw material, in the synthesis process, the aldehyde group precursor is directly oxidized to acid by using strong oxidant, then the intermediate is made to occur intramolecular Friedel-Crafts reaction by acid catalyst, finally the carbonyl / nitrogen type fluorescent material of inlaid non-benzene structure is synthesized.This structure inhibits molecular relaxation through multiple resonance effect, and then realizes narrow band emission characteristics.At the same time, the structure retains higher photoluminescence quantum yield.The carbonyl nitrogen type fluorescent material based on benzopentacyclic / septacyclic structure provided by the present application is different from the existing all benzene type polycyclic aromatic hydrocarbons, so as to effectively widen the molecular system of carbonyl / nitrogen type narrow band light emitting material.

Description

Technical Field

[0001] This invention relates to the field of fluorescent materials technology, and in particular to carbonyl nitrogen-type fluorescent materials based on benzopenta / heptacyclic structures and their preparation methods. Background Technology

[0002] In recent years, with the advancement of science and technology, organic electroluminescence devices (OLEDs) have gradually replaced traditional liquid crystal display technology and have been widely used in smart terminals, consumer electronics, display lighting, and other fields. Organic light-emitting materials, as a core element of OLED technology, play a restrictive role in the development of OLEDs. Among them, thermally activated delayed fluorescence (TADF) materials have been extensively studied in both academia and industry due to their high theoretical quantum efficiency and cost advantages. However, the spectral broadening problem caused by molecular relaxation in TADF materials is detrimental to achieving high-definition displays and also limits their industrial application. With the introduction of the concept of multiple resonance (MR), the advantages of high efficiency and high color purity of TADF materials have gradually become apparent. In constructing such novel π-conjugated systems, the construction of MR frameworks based on boron-nitrogen (BN) and carbonyl / nitrogen (C=O / N) structures is a key step. For boron-nitrogen (BN) type multiple resonance materials, the selective limitation of the borylation reaction poses a challenge to their application in complex molecules.

[0003] Therefore, how to expand the molecular system of carbonyl / nitrogen fluorescent materials and explore efficient synthetic methods for constructing carbonyl / nitrogen multiple resonance frameworks are urgent technical problems to be solved. Summary of the Invention

[0004] The present invention aims to at least solve one of the technical problems existing in the related art. Therefore, the first objective of the present invention is to provide a carbonyl nitrogen-type fluorescent material based on a benzopenta / heptacyclic structure; the second objective of the present invention is to provide a method for preparing a carbonyl nitrogen-type fluorescent material based on a benzopenta / heptacyclic structure.

[0005] To achieve the first objective, the technical solution adopted by this invention is as follows:

[0006] Carbonyl nitrogen-type fluorescent materials based on benzopenta / heptacyclic structures are selected from any of the following structural formulas:

[0007] , , ;

[0008] In the structural formula, R1, R2 and R3 are each independently selected from -C(CH3)3, -CH(CH3)2 or -CH2C(CH3)2.

[0009] Preferably, it is selected from any of the following structural formulas:

[0010] , , ;

[0011] In the structural formula, tBu is -C(CH3)3.

[0012] Preferably, the peak value of the fluorescence spectrum is between 450 and 550 nm.

[0013] Preferably, it is used as a doping component in the light-emitting layer of an organic electroluminescent device.

[0014] Preferably, the main molecule of the luminescent layer is selected from 2,6-bis[3-(9H-carbazole-9-yl)phenyl]pyridine or N-(1-naphthyl)-N-phenyl-9,10-dinaphthylanthramine, and the doping ratio of the carbonyl nitrogen-type fluorescent material based on the benzopenta / heptacyclic structure is 1wt% to 4wt%.

[0015] Preferably, the host molecule of the luminescent layer is selected from 2,6-bis[3-(9H-carbazole-9-yl)phenyl]pyridine, and the carbonyl nitrogen-type fluorescent material based on the benzopenta / heptacyclic structure is selected from N4 or N15;

[0016] Alternatively, the host molecule of the luminescent layer may be selected from N-(1-naphthyl)-N-phenyl-9,10-dinaphthylanthramine, and the carbonyl nitrogen-type fluorescent material based on the benzopenta / heptacyclic structure may be selected from N11.

[0017] To achieve the second objective, the technical solution adopted by this invention is as follows:

[0018] A method for preparing carbonyl nitrogen-based fluorescent materials with a benzopenta / heptacyclic structure, comprising the following steps:

[0019] S100, with and Using raw materials, intermediate N-1 was synthesized, with the following structural formula: ;

[0020] S200, using intermediate N-1 and The reaction synthesizes intermediate N-2, with the following structural formula: ;

[0021] S300. Intermediate N-3 was synthesized via lithium halide exchange and nucleophilic addition-elimination reactions of intermediate N-2, with the following structural formula: ;

[0022] S400, by reacting intermediate N-3 sequentially with a strong oxidant and an acid catalyst, synthesizes carbonyl nitrogen-type fluorescent materials based on a benzopenta / heptacyclic structure.

[0023] Preferably, in step S400, the strong oxidant is selected from potassium permanganate, and / or the acid catalyst is selected from polyphosphoric acid.

[0024] A method for preparing carbonyl nitrogen-based fluorescent materials with a benzopenta / heptacyclic structure, comprising the following steps:

[0025] S10, with Using raw materials, the synthetic intermediate N-5 is synthesized, with the following structural formula: ;

[0026] S20, utilizing intermediate N-5 and The reaction synthesized intermediate N-6, with the following structural formula: ;

[0027] S30. Intermediate N-7 was synthesized by reacting intermediate N-6 with isopropanol pinacol borate, with the following structural formula: ;

[0028] Bpin is a pinacol borate ester group;

[0029] S40. Intermediate N-8 is synthesized by reacting intermediates N-6 and N-7, with the following structural formula:

[0030] ;

[0031] S50, utilizing intermediate N-8 and The reaction synthesized intermediate N-9, with the following structural formula:

[0032] ;

[0033] S60. Intermediate N-10 was synthesized using lithium halide exchange and nucleophilic addition-elimination reactions of intermediate N-9, with the following structural formula:

[0034] ;

[0035] S70, using intermediate N-10, reacts sequentially with a strong oxidant and an acid catalyst to synthesize a carbonyl nitrogen-type fluorescent material based on a benzopenta / heptacyclic structure.

[0036] Preferably, in step S70, the strong oxidant is selected from potassium permanganate, and / or the acid catalyst is selected from polyphosphoric acid.

[0037] A method for preparing carbonyl nitrogen-based fluorescent materials with a benzopenta / heptacyclic structure, comprising the following steps:

[0038] S1, with Using raw materials, the synthetic intermediate N-5 is synthesized, with the following structural formula: ;

[0039] S2, using intermediate N-5 and The reaction synthesized intermediate N-12, with the following structural formula:

[0040] ;

[0041] S3, using intermediate N-12 and The reaction synthesized intermediate N-13, with the following structural formula:

[0042] ;

[0043] S4. Using the nucleophilic addition-elimination reaction of intermediate N-13, intermediate N-14 was synthesized, with the following structural formula:

[0044] ;

[0045] S5. By reacting intermediate N-14 sequentially with a strong oxidant and an acid catalyst, carbonyl nitrogen-type fluorescent materials based on the benzopenta / heptacyclic structure are synthesized.

[0046] Preferably, in step S5, the strong oxidant is selected from potassium permanganate, and / or the acid catalyst is selected from polyphosphoric acid.

[0047] The above-described one or more technical solutions in the embodiments of the present invention have at least one of the following technical effects:

[0048] The present invention provides a method for preparing carbonyl nitrogen-type fluorescent materials based on a benzopenta / heptacyclic structure. Using carbazole as a raw material, the synthesis process involves directly oxidizing the aldehyde precursor to an acid using a strong oxidant. Subsequently, an intramolecular Friedel-Crafts reaction is catalyzed by an acid catalyst, ultimately synthesizing a carbonyl nitrogen-type fluorescent material with an embedded tetracarbonyl group as its conjugated backbone. This structure enhances the multiple resonance effect while suppressing molecular relaxation, thus achieving narrow-band emission while retaining photoluminescence quantum yield (PLQY) and thermally activated delayed fluorescence (TADF) characteristics.

[0049] The carbonyl nitrogen-type fluorescent material based on the benzopenta / heptacyclic structure provided by this invention offers a fluorescent material that differs from existing benzene-type polycyclic aromatic hydrocarbons, thus broadening the sources of carbonyl / nitrogen-type narrow-band luminescent materials.

[0050] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0051] Figure 1 This is the carbonyl nitrogen-type fluorescent material N-4 based on a benzopenta / heptacyclic structure provided in Example 1 of the present invention. 1 HNMR spectrum.

[0052] Figure 2 This is the carbonyl nitrogen-type fluorescent material N-4 based on a benzopenta / heptacyclic structure provided in Example 1 of the present invention. 13 CNMR spectrum.

[0053] Figure 3 This is the carbonyl nitrogen-type fluorescent material N-11 based on a benzopenta / heptacyclic structure provided in Example 2 of the present invention. 1 HNMR spectrum.

[0054] Figure 4 This is the carbonyl nitrogen-type fluorescent material N-11 based on a benzopenta / heptacyclic structure provided in Example 2 of the present invention. 13 CNMR spectrum.

[0055] Figure 5 This is the carbonyl nitrogen-type fluorescent material N-15 based on a benzopenta / heptacyclic structure provided in Example 3 of the present invention. 1 HNMR spectrum.

[0056] Figure 6 This is the carbonyl nitrogen-type fluorescent material N-15 based on a benzopenta / heptacyclic structure provided in Example 3 of the present invention. 13CNMR spectrum.

[0057] Figure 7 These are the UV-Vis absorption and fluorescence (PL) spectra of three carbonyl nitrogen-type fluorescent materials, N-4, N-11, and N-15, based on the benzopenta / heptacyclic structure, provided in the test examples of this invention.

[0058] Figure 8 The fluorescence and phosphorescence spectra of three carbonyl nitrogen-type fluorescent materials, N-4, N-11, and N-15, based on the benzopenta / heptacyclic structure, provided in the test examples of this invention, are observed at a low temperature of -196°C. Detailed Implementation

[0059] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with specific embodiments. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention. The following embodiments are used to illustrate this invention, but cannot be used to limit the scope of this invention.

[0060] In the following embodiments, unless otherwise specified, the experimental methods used are conventional methods, and the materials and reagents used are commercially available, unless otherwise specified, and are carried out in accordance with the techniques or conditions described in the literature in this field or in accordance with the product instructions.

[0061] Example 1

[0062] Carbonyl nitrogen-based fluorescent materials based on benzopenta / heptacyclic structures The synthetic route is shown below:

[0063]

[0064] Its synthesis process is as follows:

[0065] I. Synthetic intermediate N-1.

[0066] Under a nitrogen atmosphere, 1-iodonaphthalene (2.54 g, 10.0 mmol), 3,6-di-tert-butyl-9H-carbazole (4.19 g, 15 mmol), cuprous iodide (0.19 g, 10.0 mmol), 18-crown ether-6 (0.26 g, 10.0 mmol), and cesium carbonate (6.52 g, 20.0 mmol) were dissolved in o-dichlorobenzene (30 mL). After three gas exchanges, the mixture was heated to 190 °C and stirred for 48 h. After cooling to room temperature, insoluble matter was removed by filtration, and the solvent was removed by vacuum distillation. The crude product was separated by column chromatography (mobile phase: a mixture of petroleum ether and dichloromethane at a volume ratio of 10:1). The fraction was collected and dried by rotary evaporation to obtain a white solid powder (3.20 g) of intermediate N-1. Its characterization data are as follows:

[0067] 1 H NMR (400MHz, CDCl3): δ 8.20 (d, J =1.6 Hz, 2H), 8.01 (dd, J =8.0, 2.8Hz, 2H), 7.68-7.58 (m, 2H), 7.55-7.51 (m, 1H), 7.46-7.45 (m, 1H), 7.41-7.31 (m, 4H), 6.92 (d, J =8.0 Hz, 2H), 1.39 (d, J =2.6 Hz, 18 H);

[0068] 13 C NMR (101MHz, CDCl3): δ 142.57, 140.71, 134.83, 134.61, 128.65, 128.39, 126.79, 126.62, 126.51, 125.93, 123.83, 123.60, 123.17, 116.21, 109.62, 34.77, 32.09.

[0069] II. Synthetic intermediate N-2.

[0070] Under a nitrogen atmosphere, intermediate N-1 (4.50 g, 10.0 mmol) was dissolved in chloroform (50 mL). N-bromosuccinimide (4.35 g, 22 mmol) was added in an ice bath. The mixture was stirred and reacted at room temperature for 48 h. After filtration to remove insoluble matter, the solvent was removed by vacuum distillation. The crude product was separated by column chromatography (mobile phase: a 1:1 mixture of petroleum ether and dichloromethane). The fraction was collected, recrystallized from methanol, and dried by rotary evaporation to obtain intermediate N-2 as a white solid powder (5.21 g). Its characterization data are as follows:

[0071] 1 H NMR (400MHz, CDCl3): δ 8.1 (s, 2H), 8.06 (d, J =8.0 Hz, 1H), 7.96 (d, J =8.2Hz, 1H), 7.61–7.48 (m, 5H), 7.36 (t, J =8.0 Hz, 1H), 7.22 (d, J =8.5 Hz, 1H), 1.45 (s, 18H);

[0072] 13 C NMR (101MHz, CDCl3): δ 144.70, 139.11, 137.07, 136.99, 136.89, 136.73, 135.69, 134.92, 132.00, 130.21, 130.11, 128.1 3, 127.26, 127.07, 126.82, 125.32, 124.75, 122.35, 115.54, 103.47, 34.73, 31.84, 21.21, 20.36.

[0073] III. Synthetic intermediate N-3.

[0074] Under a nitrogen atmosphere, intermediate N-2 (5.00 g, 0.01 mol) was dissolved in tetrahydrofuran (50 mL), cooled to -78 °C, and 2.5 M n-butyllithium hexane solution (8.0 mL) was slowly added dropwise. After reacting at this temperature for 1 h, anhydrous N,N-dimethylformamide (0.78 g, 0.1 mol) was added, followed by warming to room temperature and quenching with water. The solvent was removed by rotary evaporation, and the mixture was extracted with dichloromethane. The crude product was separated by column chromatography (mobile phase: a mixture of petroleum ether and dichloromethane in a volume ratio of 1:2). The fraction was collected, dried by rotary evaporation, and intermediate N-3 was obtained as a white solid powder (3.68 g). Its characterization data are as follows:

[0075] 1 H NMR (400MHz, CDCl3): δ 9.06 (s, 2H), 8.48 (d, J =2.1 Hz, 2H), 8.15 (dd, J =8.3, 1.3 Hz, 1H), 8.10 (d, J =2.0 Hz, 2H), 8.04 (d, J =8.3 Hz, 1H), 7.74 (m, 1H), 7.68-7.64 (m, 1H), 7.59 (ddd, J=8.2, 5.2, 2.9 Hz, 1H), 7.42-7.41 (m, 2H), 1.49 (s, 18H);

[0076] 13 C NMR (101MHz, CDCl3): δ 149.57, 147.65, 144.38, 138.07, 136.23, 133.05, 131.57, 128.45, 125.96, 125.85, 120.06, 35.10, 30.87, 21.34, 19.94.

[0077] IV. Synthesis of N-4, a carbonyl nitrogen-type fluorescent material based on a benzopenta / heptacyclic structure.

[0078] Under a nitrogen atmosphere, intermediate N-3 (2.54 g, 0.01 mol) was dissolved in acetone (500 mL). Potassium permanganate (7.90 g, 0.05 mol) was added at room temperature, and the mixture was heated to 50 °C and reacted for 6 h. The mixture was then filtered while hot, and the solvent was removed by vacuum evaporation. The solution was dissolved in deionized water (50 mL), and the pH was adjusted to 1 with dilute hydrochloric acid. The mixture was filtered again to obtain a solid powder (2.0 g). This solid powder was dried, and under a nitrogen atmosphere, polyphosphoric acid (5.0 mL) was added. The mixture was heated to 120 °C and reacted for 4 h. After cooling to room temperature, deionized water (60 mL) was added, and the pH was adjusted to neutral with dilute sodium hydroxide solution. The mixture was filtered, and the crude product was separated by column chromatography (mobile phase: a 1:3 volume ratio of petroleum ether and dichloromethane). The fraction was collected, dried by rotary evaporation, and a yellow solid powder (1.32 g) of carbonyl nitrogen-based fluorescent material N-4, based on a benzo[5] / [7]-heptacyclic ring structure, was obtained. 1 H NMR spectra and 13 The C NMR spectra are as follows: Figure 1 and Figure 2 As shown;

[0079] Its characterization data are as follows:

[0080] 1 H NMR (400MHz, CDCl3): δ 8.77–8.69 (m, 2H), 8.56 (d, J =1.8 Hz, 1H), 8.48 (d, J =1.8 Hz, 1H), 8.39 (q, J =2.0 Hz, 2H), 8.16 (dd, J =9.4, 1.4 Hz, 1H), 7.87–7.76 (m, 2H), 1.56 (d, J =12.4 Hz, 18H);

[0081] 13 C NMR (101MHz, CDCl3): δ 188.30, 177.90, 148.43, 147.63, 137.68, 137.46, 137.35, 137.20, 136.54, 135.06, 132.03, 128.24, 126.86, 1 26.84, 125.68, 125.01, 124.80, 123.45, 123.26, 122.71, 122.64, 121.12, 119.60, 35.54, 35.07, 31.93, 31.59.

[0082] Example 2

[0083] Carbonyl nitrogen-based fluorescent materials based on benzopenta / heptacyclic structures The synthetic route is shown below:

[0084] Its synthesis process is as follows:

[0085] I. Synthetic intermediate N-5.

[0086] Sodium nitrite (6.0 g, 86.96 mmol) was dissolved in 98% concentrated sulfuric acid (60 mL) under ice bath conditions. Then, a glacial acetic acid solution (60 mL) of 1,5-dinaphthylamine (6.0 g, 37.92 mmol) was added, followed by dropwise addition of a 1.67 mg / mL potassium iodide aqueous solution (18 mL). The reaction was allowed to proceed overnight at room temperature. After the reaction was complete, deionized water (150 mL) was added, and the solvent was removed by filtration. The crude product was separated by column chromatography (mobile phase: a mixture of petroleum ether and dichloromethane at a volume ratio of 10:1). The fraction was collected, dried by rotary evaporation, and yielded a reddish-brown solid powder (3.7 g) of intermediate N-5. Its characterization data are as follows:

[0087] 1 H NMR (400MHz, CDCl3): δ 8.13 (d, 4H, J = 7.6 Hz), 7.26 Hz (t, 2H, J = 7.6hz);

[0088] 13 C NMR (101MHz, CDCl3): δ 138.54, 134.64, 133.59, 128.41, 99.68.

[0089] II. Synthetic intermediate N-6.

[0090] Under a nitrogen atmosphere, intermediate N-5 (2.54 g, 10.0 mmol), 3,6-di-tert-butyl-9H-carbazole (4.19 g, 25.0 mmol), cuprous iodide (1.90 g, 20.0 mmol), 18-crown ether-6 (0.26 g, 20.0 mmol), and cesium carbonate (6.52 g, 0.3 mmol) were dissolved in o-dichlorobenzene (50 mL). After three gas exchanges, the mixture was heated to 190 °C and stirred for 48 h. After cooling to room temperature, insoluble matter was removed by filtration, and the solvent was removed by vacuum distillation. The crude product was separated by column chromatography (mobile phase: a mixture of petroleum ether and dichloromethane in a volume ratio of 10:1). The fraction was collected, dried by rotary evaporation, and a white solid powder (4.10 g) of intermediate N-6 was obtained. Its characterization data are as follows:

[0091] 1 H NMR (400MHz, CDCl3: δ 8.96 (d, J =8.6 Hz, 3H), 7.64 (d, J =7.0 Hz, 2H), 7.60-7.39 (m, 6H), 7.03 (d, J =8.6 Hz, 3H), 1.52 (d, J =21.4 Hz, 36H);

[0092] 13 C NMR (101MHz, CDCl3): δ 142.75, 142.73, 140.87, 138.85, 134.94, 134.30, 131.30, 128.82, 127.30, 126.64, 126.32, 1 26.14, 123.94, 123.72, 123.31, 123.27, 116.33, 116.31, 109.76, 34.86, 34.84, 32.16, 32.14.

[0093] III. Synthetic intermediate N-7.

[0094] Under a nitrogen atmosphere, intermediate N-7 (2.6 g, 4.90 mmol) was dissolved in anhydrous tetrahydrofuran (60 mL). After cooling to -78 °C, a 2.5 M n-butyllithium solution in n-hexane (5.8 mL) was slowly added dropwise. After reacting at this temperature for 1 h, isopropanol pinacol borate ester (4.5 g, 24.18 mmol) was added. Then, the reaction system was gradually raised to room temperature and quenched with water. After extraction with dichloromethane and removal of the solvent by rotary evaporation, the crude product was separated by column chromatography (mobile phase: a mixture of petroleum ether and dichloromethane in a volume ratio of 1:2). The fraction was collected, dried by rotary evaporation, and a white solid powder of intermediate N-7 (2.08 g) was obtained. Its characterization data are as follows:

[0095] 1 H NMR (400MHz, CDCl3): δ 8.96 (d, J =8.6 Hz, 1H), 8.20 (d J =1.3 Hz, 2H), 8.12 (dd, J =6.8, 5.4 Hz, 1H), 7.71-7.67 (m, 1H), 7.57 (dd, J =7.2, 6.0 Hz, 1H), 7.47 (dt, J =8.4, 1.2 Hz, 1H), 7.36 (dd, J =8.6, 1.9 Hz, 2H), 7.31 (dd, J =8.5, 6.8 Hz, 1H), 6.87 (d, J =8.6 Hz, 2H), 1.47 (s, 18H);

[0096] 13 C NMR (101MHz, CDCl3): δ 142.52, 140.87, 138.26, 136.40, 134.70, 130.94, 129.30, 127.18, 126.41, 1 26.32, 125.99, 123.63, 123.14, 116.22, 109.60, 84.03, 34.80, 32.12, 25.07.

[0097] IV. Synthetic intermediate N-8.

[0098] Under a nitrogen atmosphere, intermediates N-6 (2.00 g, 3.76 mmol), N-7 (1.75 g, 4.32 mmol), potassium carbonate (7.5 g), and tetraphenylphosphine palladium (0.43 g, 0.4 mmol) were dissolved in a toluene / ethanol / water mixture (50 mL / 5 mL / 5 mL). The mixture was heated to 100 °C and reacted for 24 h. After cooling to room temperature, insoluble matter was removed by filtration, and the solvent was removed by vacuum distillation. The crude product was separated by column chromatography (mobile phase: a mixture of petroleum ether and dichloromethane in a volume ratio of 6:1). The fraction was collected and dried by rotary evaporation to obtain a white solid powder (2.70 g) of intermediate N-8. Its characterization data are as follows:

[0099] 1 H NMR (400MHz, CDCl3): δ 8.24 (d, J= 2.5 Hz, 4H), 7.86-7.61 (m, 6H), 7.54-7.41 (m, 10H) 7.10 (d, J =8.6 Hz, 2H), 7.01 (d, J =7.5 Hz, 2H), 1.50 (s, 18H), 1.49 (s, 18H);

[0100] 13 C NMR (101MHz, CDCl3): δ 142.86, 140.79, 135.25, 132.50, 127.33, 126.87, 124.49, 123.77, 123.32, 116.34, 109.67, 34.84, 32.12.

[0101] V. Synthetic intermediate N-9.

[0102] Under a nitrogen atmosphere, the intermediate (20.25 g, 0.05 mol) was dissolved in chloroform (500 mL). N-bromosuccinimide (19.8 g, 0.1 mol) was added in an ice bath. After stirring at room temperature for 48 h, the insoluble matter was removed by filtration, and the solvent was removed by vacuum distillation. The crude product was separated by column chromatography (mobile phase: a 1:1 mixture of petroleum ether and dichloromethane). The fraction was collected, recrystallized from methanol, and dried by rotary evaporation to obtain a white solid powder (25.91 g) of intermediate N-9. Its characterization data are as follows:

[0103] 1 H NMR (400MHz, CDCl3): δ 8.12 (s, J =1.8 Hz, 4H), 8.06 (d, J =8.0 Hz, 2H), 7.95 (d,J =8.2 Hz, 2H), 7.61 - 7.48 (m, 10H), 7.35 (t, J =7.3 Hz, 2H), 7.22 (d, J =8.5 Hz, 2H), 1.44 (s, 36H);

[0104] 13 C NMR (101MHz, CDCl3): δ 144.81, 144.79, 138.51, 137.16, 137.12, 135.57, 134.94, 132.91, 130.27, 130.20, 130.09, 128.48 , 128.29, 126.43, 125.46, 125.37, 124.84, 123.38, 115.62, 115.56, 103.63, 103.52, 34.75, 31.85.

[0105] VI. Synthetic intermediate N-10.

[0106] Under a nitrogen atmosphere, intermediate N-9 (25.4 g, 0.1 mol) was dissolved in tetrahydrofuran (500 mL), cooled to -78 °C, and a 2.5 M n-butyllithium solution in n-hexane (44 mL) was slowly added dropwise. After maintaining this temperature for 1 h, anhydrous N,N-dimethylformamide (7.8 g, 1 mol) was added, the mixture was heated to room temperature, quenched with water, and the solvent was removed by rotary evaporation. The product was then extracted with dichloromethane, and the crude product was separated by column chromatography (mobile phase: a mixture of petroleum ether and dichloromethane in a volume ratio of 1:2). The fraction was collected, dried by rotary evaporation, and a white solid powder (21.23 g) of intermediate N-10 was obtained. Its characterization data are as follows:

[0107] 1 H NMR (400MHz, CDCl3): δ 9.23 (d, J =9.7 Hz, 4H), 8.52 (d, J =2.0 Hz, 4H), 8.16(q, J =2.0 Hz, 4H), 7.81 (d, J =5.0Hz, 2H), 7.72-7.69 (m, 4H), 7.63-7.53 (m, 6H), 1.53 (s, 18H), 1.52 (s, 18H);

[0108] 13C NMR (101MHz, CDCl3): δ 181.13, 149.19, 143.30, 136.18, 130.55, 122.66, 116.21, 84.69, 71.52, 70.31, 58.83, 34.81, 31.20.

[0109] VII. Synthesis of N-11, a carbonyl nitrogen-type fluorescent material based on a benzopenta / heptacyclic structure.

[0110] Under a nitrogen atmosphere, the intermediate (2.54 g, 0.01 mol) was dissolved in acetone (500 mL), and potassium permanganate (7.90 g, 0.05 mol) was added at room temperature. After reacting at 50 °C for 6 h, the mixture was filtered while hot, the solvent was removed under reduced pressure, and the mixture was dissolved in deionized water (50 mL). The pH was adjusted to 1 with dilute hydrochloric acid, and the mixture was filtered to obtain a solid powder (2.0 g). After drying the solid powder, polyphosphoric acid (5.0 mL) was added under a nitrogen atmosphere, and the mixture was heated to 120 °C for 4 h. After cooling to room temperature, deionized water (60 mL) was added, and the pH was adjusted to neutral with dilute sodium hydroxide solution. The mixture was filtered, and the crude product was separated by column chromatography (mobile phase: a mixture of petroleum ether and dichloromethane in a volume ratio of 1:3). The fraction was collected, dried by rotary evaporation, and a yellow solid powder (1.32 g) of N-11, a carbonyl nitrogen-type fluorescent material based on a benzo[5] / [7]-heptacyclic ring structure, was obtained. 1 H NMR spectra and 13 The C NMR spectra are as follows: Figure 3 and Figure 4 As shown;

[0111] Its characterization data are as follows:

[0112] 1 H NMR (400MHz, CDCl3): δ 8.84 (d, J =7.7, 2H), 8.55-8.51 (m, 6H), 8.43 (s, 4H), 7.87 (d, J =7.6, 2H), 7.37 (d, J =9.2, 2H), 1.58 (s, 18H), 1.56 (s, 18H);

[0113] 13C NMR (101MHz, CDCl3): δ 189.78, 176.54, 149.15, 148.80, 139.94, 138.16, 136.47, 134.90, 130.08, 129.93, 126.77, 126.12, 125.66, 125.59, 125.42, 123.97, 123.45, 123.38, 123.22, 121.16, 119.75, 119.33, 35.57, 35.21, 31.89, 31.83, 31.77, 31.61, 31.59.

[0114] Example 3

[0115] Carbonyl nitrogen-based fluorescent materials based on benzopenta / heptacyclic structures

[0116] Carbonyl nitrogen-based fluorescent materials based on benzopenta / heptacyclic structures The synthetic route is shown below:

[0117]

[0118] Its synthesis process is as follows:

[0119] I. Synthetic intermediate N-5.

[0120] The preparation process of intermediate N-5 is the same as in Example 2.

[0121] II. Synthetic intermediate N-12.

[0122] Under a nitrogen atmosphere, intermediate N-5 (25.4 g, 0.1 mol), 3,6-di-tert-butyl-9H-carbazole (83.82 g, 0.3 mol), cuprous iodide (38.0 g, 0.2 mol), 18-crown ether-6 (5.28 g, 20.0 mmol), and cesium carbonate (130.32 g, 0.4 mol) were dissolved in o-dichlorobenzene (500 mL). The mixture was heated to 190 °C and stirred for 48 h. After cooling to room temperature, the salts were removed by filtration, and the solvent was removed by vacuum evaporation. The crude product was separated by column chromatography (mobile phase: a mixture of petroleum ether and dichloromethane in a volume ratio of 10:1). The fraction was collected and dried by rotary evaporation to obtain a white solid powder (3.7 g) of intermediate N-12. Its characterization data are as follows:

[0123] 1 H NMR (400MHz, CDCl3): δ 8.23 ​​(d, J =2.0 Hz, 4H), 7.64 (d, J =7.0 Hz, 4H), 7.56-7.43 (m, 6H), 7.03 (d,J =8.6 Hz, 4H), 1.52 (d, J =21.4 Hz, 36H);

[0124] 13 C NMR (101MHz, CDCl3): δ 142.75, 142.73, 140.87, 138.85, 134.94, 134.30, 131.30, 128.82, 127.30, 126.64, 126.32, 1 26.14, 123.94, 123.72, 123.31, 123.27, 116.33, 116.31, 109.76, 34.86, 34.84, 32.16, 32.14.

[0125] III. Synthetic intermediate N-13.

[0126] Under a nitrogen atmosphere, intermediate N-12 (20.25 g, 0.05 mol) was dissolved in chloroform (500 mL). N-bromosuccinimide (19.8 g, 0.11 mol) was added in an ice bath. After stirring at room temperature for 48 h, the reaction solvent was removed by vacuum distillation. The crude product was separated by column chromatography (mobile phase: a 1:1 mixture of petroleum ether and dichloromethane). The fraction was collected, recrystallized from methanol, and dried by rotary evaporation to obtain intermediate N-13 as a white solid powder (25.91 g). Its characterization data are as follows:

[0127] 1 H NMR (400MHz, CDCl3): δ 8.14 (d, J =1.8 Hz, 4H), 7.62 (dd, J =7.6, 1.1 Hz, 2H), 7.58 (d, J =1.7 Hz, 4H), 7.43-7.36 (m, 4H), = 1.44 (s, 36H);

[0128] 13 C NMR (101MHz, CDCl3): δ 144.81, 144.79, 138.51, 137.16, 137.12, 135.57, 134.94, 132.91, 130.27, 130.20, 130.09, 128.48 , 128.29, 126.43, 125.46, 125.37, 124.84, 123.38, 115.62, 115.56, 103.63, 103.52, 34.75, 31.85.

[0129] IV. Synthetic intermediate N-14.

[0130] Under a nitrogen atmosphere, intermediate N-13 (25.4 g, 0.1 mol) was dissolved in anhydrous tetrahydrofuran (500 mL). After cooling to -78 °C, a 1.3 M tert-butyllithium solution in n-hexane (44 mL) was slowly added dropwise. After reacting at this temperature for 1 h, anhydrous N,N-dimethylformamide (7.8 g, 1 mol) was added. The mixture was heated to room temperature and quenched with water. After removing the solvent by rotary evaporation, the product was extracted with dichloromethane. After removing the solvent, the crude product was separated by column chromatography (mobile phase: a mixture of petroleum ether and dichloromethane in a volume ratio of 1:4). The fraction was collected, dried by rotary evaporation, and a light yellow solid powder (21.23 g) of intermediate N-14 was obtained. Its characterization data are as follows:

[0131] 1 H NMR (400MHz, CDCl3): δ 9.25 (s, 4H), 8.50 (d, J =2.0 Hz, 4H), 8.09 (d, J =3.3Hz, 4H), 7.82 (dd, J =5.0, 3.4 Hz, 2H), 7.56- 7.54 (m, 4H), 1.53 (s, 36H);

[0132] 13 C NMR (101MHz, CDCl3): δ 81.13, 149.19, 143.30, 136.18, 130.55, 122.66, 116.21, 84.69, 71.52, 70.31, 58.83, 34.81, 31.20.

[0133] V. Synthesis of N-15, a carbonyl nitrogen-type fluorescent material based on a benzopenta / heptacyclic structure.

[0134] Intermediate N-14 (2.54 g, 0.01 mol) was dissolved in acetone (500 mL), and potassium permanganate (7.90 g, 0.05 mol) was added at room temperature. The mixture was refluxed at 60 °C for 6 h, filtered while hot to remove the reaction solvent, and then deionized water (300 mL) was added. After adjusting the pH to 1 with dilute sulfuric acid, a light yellow solid precipitated out. Filtering yielded 2.0 g of solid powder. Under a nitrogen atmosphere, the solid powder was dissolved in polyphosphoric acid (5.0 mL), and reacted at 120 °C for 4 h. Then, deionized water (60 mL) was added, and the pH was adjusted to neutral with dilute sodium hydroxide solution. Filtering yielded a crude product. The crude product was separated by column chromatography (mobile phase: a mixture of petroleum ether and dichloromethane in a volume ratio of 1:3). The fraction was collected, dried by rotary evaporation, and a red solid powder (1.32 g) of carbonyl nitrogen-based fluorescent material N-15 based on a benzo[5 / 7]-ring structure was obtained.1 H NMR spectra and 13 The C NMR spectra are as follows: Figure 5 and Figure 6 As shown;

[0135] Its characterization data are as follows:

[0136] 1 H NMR (400MHz, CDCl3): δ 9.41 (s, 2H), 8.50 (dd, J =12.6, 1.8 Hz, 4H), 8.35(d, J =2.0 Hz, 2H), 8.28 (d, J =2.1 Hz, 2H), 1.56 (d, J =1.2 Hz, 36H);

[0137] 13 C NMR (101MHz, CDCl3) δ 189.78, 176.54, 149.15, 148.80, 139.94, 138.16, 136.47, 134.90, 130.08, 129.93, 126.77, 126.12, 125.66, 125.59, 125.42, 123.97, 123.45, 123.38, 123.22, 121.16, 119.75, 119.33, 35.57, 35.21, 31.89, 31.83, 31.77, 31.61, 31.59.

[0138] Test Example

[0139] The ultraviolet-visible absorption (UV-Vis) and fluorescence (PL) spectra of N-4, N-11, and N-15 were detected as follows:

[0140] N-4, N-11, and N-15 were pre-prepared to a concentration of approximately 5.0 × 10⁻⁶. -3 mol·L -1 A toluene (Tol) solution was prepared, and then the solution was diluted to 5 × 10⁻⁶. -5 mol·L -1 Subsequently, ultraviolet-visible absorption (UV-Vis) and fluorescence spectroscopy (PL) were performed, and the results are as follows: Figure 7 As shown;

[0141] Figure A shows the UV-Vis absorption spectra of N-4, N-11, and N-15. From this figure, we can see that they have obvious absorption peaks in the 310-500 nm range, indicating that these substances respond to UV-Vis light.

[0142] Figure B shows the fluorescence spectra of N-4, N-11, and N-15. From this figure, we can see that their peaks are concentrated between 450 and 550 nm, which is the emission region of visible light (such as blue light and green light).

[0143] In addition, the above concentration is 5×10 -5 mol·L -1 The N-4, N-11, and N-15 fluorescent materials were placed in a cryostat (liquid nitrogen) and excited with a xenon lamp. The low-temperature fluorescence and phosphorescence spectra of the compounds at -196 °C (77 K) were measured using a steady-state-transient fluorescence spectrometer. The results are as follows: Figure 8 As shown.

[0144] Example 4

[0145] An organic electroluminescent device was constructed using vacuum evaporation technology, consisting of ITO / TAPC (35nm), an emissive layer (20nm), TmPyPB (45nm), Liq (1nm), and Al (100nm). The process is as follows:

[0146] The ITO substrate was ultrasonically cleaned with cleaning solution, deionized water, ethanol and acetone for 15 minutes in sequence, then dried at 75°C. The cleaned ITO substrate was then placed in a clean bench and the ITO surface was dried with high-speed nitrogen. Finally, the ITO surface was subjected to plasma treatment for 5 minutes to obtain the treated ITO substrate.

[0147] The treated substrate is then transferred to a high-vacuum evaporation chamber (vacuum degree <5×10). -4 TAPC, the luminescent layer, and TmPyPB organic functional material were sequentially deposited onto an ITO substrate at a rate of 1.0 Å / s. After the organic functional material was deposited, the ITO glass was patterned using a mask with a 2.0 mm × 2.5 mm aperture array, followed by the sequential deposition of Lip and Al layers at rates of 0.1 Å / s and 5.0 Å / s, respectively.

[0148] Wherein, ITO is indium tin oxide, TAPC is bis[4-(N,N-diphenylamino)phenyl]cyclohexane, EML is the emissive layer, TmPyPB is 1,3,5-tris(3-pyridyl-phenyl)benzene, Liq is lithium 8-hydroxyquinoline, and Al is lithium metal;

[0149] When the emitting layer is based on 2,6-DCzPPy, it is doped with carbonyl nitrogen-type fluorescent materials N-4 and N-15, which are based on the benzopenta / heptacyclic structure obtained in Examples 1 and 3, respectively; when the emitting layer is based on NPADN, it is doped with carbonyl nitrogen-type fluorescent material N-11, which is based on the benzopenta / heptacyclic structure obtained in Example 2. Specific results are as follows:

[0150] When fabricating blue-green light-emitting devices using 2,6-DCzPPy as the host molecule and N-4 (mass concentration of 1wt%–4wt%) as the guest molecule in the emitting layer, the device performance is optimal when the doping concentration is 3wt%, as detailed below: Maximum External Quantum Efficiency (EQE) max The maximum current efficiency (CEmax) is 17.9%, the maximum power efficiency (PEmax) is 1.6 cd / A, the maximum power efficiency (PEmax) is 1.0 lumen per watt (lm / W), and the peak wavelength of the electroluminescence (EL) spectrum is 500 nm.

[0151] A green light-emitting device was fabricated using 2,6-DCzPPy as the host molecule and N-15 (mass concentration of 1wt%–4wt%) as the guest molecule. As the guest molecule proportion increased, the device efficiency improved, and the peak wavelength of the EL spectrum redshifted from 522nm to 528nm. The device performance was optimal when the N-15 doping ratio was 4wt%, as detailed below: EQE max It was 19.1%, CE max It is 6.8 cd / A, PE max It has a brightness of 4.5 lumens per watt (lm / W) and an EL spectrum peak corresponding to a wavelength of 528 nm.

[0152] When fabricating blue-green light-emitting devices with NPADN as the host molecule and N-11 (mass concentration of 1wt%–4wt%) as the guest molecule in the emitting layer, the device efficiency first increases and then decreases as the doping ratio of the guest molecule in the emitting layer gradually increases. The peak wavelength of the EL spectrum redshifts from 480nm to 484nm. The device performance is optimal when the doping concentration is 2wt%, as detailed below: EQE max It is 10.2%, CE max It has an efficiency of 2.0 cd / A, a PEmax of 0.8 lumens per watt (lm / W), and an EL spectral peak corresponding to a wavelength of 480 nm.

[0153] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A carbonyl nitrogen-type fluorescent material based on a benzopenta / heptacyclic structure, characterized in that, Choose from any of the following structural formulas: 、 、 ； In the structural formula, R1, R2 and R3 are each independently selected from -C(CH3)3 or -CH(CH3)2.

2. The carbonyl nitrogen-type fluorescent material based on the benzopenta / heptacyclic structure as described in claim 1, characterized in that, Choose from any of the following structural formulas: 、 、 ； In the structural formula, tBu is -C(CH3)3.

3. The carbonyl nitrogen-type fluorescent material based on a benzopenta / heptacyclic structure as described in claim 1 or 2, characterized in that, The peak of the fluorescence spectrum is between 450 and 550 nm.

4. A method for preparing carbonyl nitrogen-type fluorescent materials based on benzopenta / heptacyclic structures, characterized in that, The preparation of the carbonyl nitrogen-type fluorescent material based on the benzopenta / heptacyclic structure as described in claim 2, with the structural formula N-4, comprises the following steps: S100, with and Using raw materials, intermediate N-1 was synthesized, with the following structural formula: ; S200, using intermediate N-1 and The reaction synthesizes intermediate N-2, with the following structural formula: ; S300. Intermediate N-3 was synthesized via lithium halide exchange and nucleophilic addition-elimination reactions of intermediate N-2, with the following structural formula: ; S400, by reacting intermediate N-3 sequentially with a strong oxidant and an acid catalyst, synthesizes carbonyl nitrogen-type fluorescent materials based on a benzopenta / heptacyclic structure.

5. A method for preparing carbonyl nitrogen-type fluorescent materials based on benzopenta / heptacyclic structures, characterized in that, The preparation of the carbonyl nitrogen-type fluorescent material based on the benzopenta / heptacyclic structure as described in claim 2, with the structural formula N-11, includes the following steps: S10, with Using raw materials, the synthetic intermediate N-5 is synthesized, with the following structural formula: ; S20, utilizing intermediate N-5 and The reaction synthesized intermediate N-6, with the following structural formula: ; S30. Intermediate N-7 was synthesized by reacting intermediate N-6 with isopropanol pinacol borate, with the following structural formula: ; Bpin is a pinacol borate ester group; S40. Intermediate N-8 is synthesized by reacting intermediates N-6 and N-7, with the following structural formula: ； S50, utilizing intermediate N-8 and The reaction synthesized intermediate N-9, with the following structural formula: ； S60. Intermediate N-10 was synthesized using lithium halide exchange and nucleophilic addition-elimination reactions of intermediate N-9, with the following structural formula: ； S70, using intermediate N-10, reacts sequentially with a strong oxidant and an acid catalyst to synthesize a carbonyl nitrogen-type fluorescent material based on a benzopenta / heptacyclic structure.

6. A method for preparing carbonyl nitrogen-type fluorescent materials based on benzopenta / heptacyclic structures, characterized in that, The preparation of the carbonyl nitrogen-type fluorescent material based on the benzopenta / heptacyclic structure as described in claim 2, with the structural formula N-15, comprises the following steps: S1, with Using raw materials, the synthetic intermediate N-5 is synthesized, with the following structural formula: ; S2, using intermediate N-5 and The reaction synthesized intermediate N-12, with the following structural formula: ； S3, using intermediate N-12 and The reaction synthesized intermediate N-13, with the following structural formula: ； S4. Using the nucleophilic addition-elimination reaction of intermediate N-13, intermediate N-14 was synthesized, with the following structural formula: ； S5. By reacting intermediate N-14 sequentially with a strong oxidant and an acid catalyst, carbonyl nitrogen-type fluorescent materials based on the benzopenta / heptacyclic structure are synthesized.

7. The method for preparing carbonyl nitrogen-type fluorescent materials based on benzopenta / heptacyclic structures as described in any one of claims 4 to 6, characterized in that, The strong oxidant is selected from potassium permanganate, and / or the acid catalyst is selected from polyphosphoric acid.

8. Application of carbonyl nitrogen-type fluorescent materials based on benzopenta / heptacyclic structures, characterized in that, The carbonyl nitrogen-type fluorescent material based on the benzopenta / heptacyclic structure described in claim 2 is used as a doping component of the light-emitting layer of an organic electroluminescent device.

9. The application of the carbonyl nitrogen-type fluorescent material based on the benzopenta / heptacyclic structure as described in claim 8, characterized in that, The main molecule of the luminescent layer is selected from 2,6-bis[3-(9H-carbazole-9-yl)phenyl]pyridine or N-(1-naphthyl)-N-phenyl-9,10-dinaphthylanthramine, and the doping ratio of the carbonyl nitrogen-type fluorescent material based on the benzopenta / heptacyclic structure is 1wt% to 4wt%.

10. The application of the carbonyl nitrogen-type fluorescent material based on the benzopenta / heptacyclic structure as described in claim 8, characterized in that, The host molecule of the luminescent layer is selected from 2,6-bis[3-(9H-carbazole-9-yl)phenyl]pyridine, and the carbonyl nitrogen-type fluorescent material based on the benzopenta / heptacyclic structure is selected from N4 or N15; Alternatively, the host molecule of the luminescent layer may be selected from N-(1-naphthyl)-N-phenyl-9,10-dinaphthylanthramine, and the carbonyl nitrogen-type fluorescent material based on the benzopenta / heptacyclic structure may be selected from N11.

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