Aryl boron-nitrogen narrow-emission fluorescent material as well as preparation method and application thereof

Abstract

According to the aryl boron nitrogen narrow-emission fluorescent material and the preparation method and application thereof, groups with different electron donating capacities are introduced to the periphery of aryl boron nitrogen, an organic light-emitting material with the space charge transfer characteristic is formed, the structure of a device is simplified, and the performance and the service life of the device are improved. The narrow-emission fluorescent material has unique narrow-band emission, high luminous intensity and delayed fluorescence, good thermal stability and good solubility, and has remarkable economic value in the application aspects of preparation of luminescent materials, luminescent devices or intelligent materials and the like.

Description

Technical Field

[0001] The present application relates to the technical field of organic optical materials, and more specifically, to an aromatic boron nitrogen-based narrow emission fluorescent material and a preparation method and application thereof. Background Art

[0002] Organic light-emitting diodes (OLEDs) are a new type of display technology with the characteristics of high brightness, low power consumption, fast response, wide viewing angle, good flexibility, and high luminous efficiency. They are widely used in high-tech fields such as smart phones, laptops, and smart wearable devices. Among them, OLED devices are of decisive significance to display technologies such as full-color display and solid-state luminescence. Up to now, although there have been many reports on thermally activated delayed fluorescence materials based on small molecule organic light-emitting diodes, the distorted donor-acceptor structure will make its reorganization energy very large, resulting in a large emission peak width. In addition, its structural relaxation is also very large, resulting in low electroluminescence efficiency.

[0003] Therefore, developing a thermally activated delayed fluorescent material with high color purity and high quantum yield for use in organic electroluminescent devices has important research significance and economic value.

[0004] Application Contents

[0005] In order to overcome one of the problems existing in the above-mentioned prior art, the primary purpose of the present application is to provide a narrow emission fluorescent material of the aromatic boron nitrogen type. The fluorescent material has an electron-donating group, a unique multi-resonance rigid skeleton group and a multi-benzene ring structure, wherein different electron-donating groups are introduced to the periphery of the aromatic boron nitrogen, so that there is spatial charge transfer, thereby improving the life of the light-emitting device; the multi-benzene ring structure enables it to have aggregation-induced luminescence enhancement performance; and the multi-resonance rigid skeleton group has the advantages of higher quantum yield and narrower half-peak width, which solves the problems of low electroluminescence efficiency and insufficient fluorescence color purity of thermally activated delayed materials in current organic electroluminescent devices.

[0006] Another object of the present application is to provide a method for preparing the above-mentioned aromatic boron nitrogen narrow emission fluorescent material.

[0007] Another object of the present application is to provide an application of the above-mentioned aromatic boron nitrogen-based narrow emission fluorescent material.

[0008] The above-mentioned purpose of this application is achieved through the following technical solutions:

[0009] An aromatic boron nitrogen-based narrow emission fluorescent material can be used for organic small molecule optoelectronic functional materials, comprising an electron donating group, a multi-resonance rigid structure and a multi-benzene ring group, and the aromatic boron nitrogen-based narrow emission fluorescent material has a molecular structure as shown in formula (I):

[0010]

[0011] Wherein, D is the electron donating group.

[0012] The narrow emission fluorescent material provided by the present application has an electron donating group, a unique multi-benzene ring group and a multi-resonance rigid skeleton, wherein different electron donating groups are introduced around the aromatic boron nitrogen so that there is space charge transfer, thereby improving the life of the light-emitting device; the multi-benzene ring group prevents the π-π stacking of molecules, reduces the influence of aggregation-induced quenching (ACQ) and thus reduces energy loss; and the multi-resonance rigid skeleton has a higher quantum yield and very high color purity, and the combination of the two can form a molecule with a donor-acceptor structure.

[0013] The present application uses a multi-resonance mother core framework as the acceptor core, and forms a specific donor-acceptor structure by modifying different groups, so that the prepared fluorescent material has unique narrow-band emission, high luminous intensity, high quantum yield and color purity, and can be well used in the light-emitting layer of OLED.

[0014] The present application also provides a method for preparing the above-mentioned aromatic boron nitrogen narrow emission fluorescent material, comprising the following steps:

[0015] S1. Synthesize the multi-resonance fragment DtCzB-Bpin, the structural formula of DtCzB-Bpin is shown below;

[0016]

[0017] S2. Carbazole and 2-bromo-4-iodotoluene are reacted by Ullmann reaction to obtain a bromine-substituted compound containing carbazole;

[0018] S3. The bromine-substituted compound containing carbazole and bromophenylboronic acid are reacted by Suzuki reaction to obtain a bromine-substituted compound containing a polyphenyl ring structure;

[0019] S4. The bromine-substituted compound containing a polyphenyl ring structure prepared in step S3 and the DtCzB-Bpin prepared in step S1 are reacted by Suzuki reaction to obtain a fluorescent material labeled 1;

[0020] S5. obtaining a polyphenyl ring-containing substituted compound by subjecting the cyclopentadienone compound to a carbon-oxygen addition reaction;

[0021] S6. The bromine-substituted compound containing a polyphenyl ring structure prepared in step S5 and the DtCzB-Bpin prepared in step S1 are reacted by Suzuki reaction to obtain a fluorescent material labeled 15;

[0022] The present application also provides the use of the above-mentioned aromatic boron nitrogen-based narrow emission fluorescent material as a light-emitting material or a smart material.

[0023] The present application also provides the use of the above-mentioned aromatic boron nitrogen narrow emission fluorescent material in the preparation of OLED devices.

[0024] Compared with the prior art, the beneficial effects of this application are:

[0025] (1) The narrow emission fluorescent material of the aromatic boron nitrogen type provided in the present application has an electron donating group, a unique multi-benzene ring group and a multi-resonance rigid skeleton. Different electron donating groups are introduced into the periphery of the aromatic boron nitrogen, so that there is space charge transfer, thereby improving the life of the light-emitting device; the multi-benzene ring structure prevents molecular π-π stacking; the multi-resonance rigid structure has a high quantum yield and color purity, and can form a donor-acceptor structure; it can be widely used in the fields of color display and solid-state lighting, and is used to prepare light-emitting materials, light-emitting devices or smart materials.

[0026] (2) The present application uses a multi-resonance rigid structure as the receptor core, forms a specific donor-acceptor structure by modifying different electron-donating groups, introduces different electron-donating groups around the aromatic boron nitrogen, and combines the two to form a molecule with a donor-acceptor structure. The multi-resonance structure containing multiple benzene rings has a large plane and a large conjugated structure, which can enable the molecule to obtain a high fluorescence quantum yield. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is the hydrogen spectrum of the aromatic boron nitrogen-based narrow emission fluorescent material M1 prepared in Example 2.

[0028] Figure 2 This is the mass spectrum of the aromatic boron nitrogen-based narrow emission fluorescent material M1 prepared in Example 2.

[0029] Figure 3 This is the hydrogen spectrum of the aromatic boron nitrogen-based narrow emission fluorescent material M2 prepared in Example 3.

[0030] Figure 4 This is the mass spectrum of the aromatic boron nitrogen-based narrow emission fluorescent material M2 prepared in Example 3.

[0031] Figure 5 The ultraviolet-visible absorption spectrum and fluorescence emission spectrum of the aromatic boron nitrogen narrow emission fluorescent material M1 prepared in Example 2 are shown.

[0032] Figure 6 The ultraviolet-visible absorption spectrum and fluorescence emission spectrum of the aromatic boron nitrogen narrow emission fluorescent material M2 prepared in Example 3 are shown. DETAILED DESCRIPTION

[0033] The embodiments of the present application will be described in detail below in conjunction with the examples, but it will be appreciated by those skilled in the art that the following examples are only used to illustrate the present application and should not be considered as limiting the scope of the present application. In the examples, if specific conditions are not specified, they are carried out according to normal conditions or the conditions recommended by the manufacturer. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0034] It should be noted that:

[0035] In this application, unless otherwise specified, all the embodiments and preferred implementation methods mentioned herein can be combined with each other to form a new technical solution.

[0036] In the present application, unless otherwise specified, percentage (%) or part refers to the weight percentage or weight part relative to the composition.

[0037] In the present application, unless otherwise specified, the components or preferred components involved can be combined with each other to form a new technical solution.

[0038] In this application, unless otherwise specified, the numerical range "a-b" represents an abbreviation of any real number combination between a and b, where a and b are real numbers. For example, the numerical range "1-5" means that all real numbers between "1-5" are listed in this document, and "1-5" is just an abbreviation of these numerical combinations.

[0039] The "range" disclosed in the present application is in the form of a lower limit and an upper limit, which can be one or more lower limits, and one or more upper limits, respectively.

[0040] In the present application, unless otherwise specified, each reaction or operation step can be carried out sequentially or in accordance with the sequence. Preferably, the reaction method herein is carried out sequentially.

[0041] Unless otherwise specified, the professional and scientific terms used herein are the same as those familiar to those skilled in the art. In addition, any method or material similar or equivalent to the described content may also be applied to the present application.

[0042] The present application provides an aromatic boron nitrogen-based narrow emission fluorescent material, which can be used for organic small molecule optoelectronic functional materials, comprising an electron donating group, a multi-resonance rigid structure and a multi-benzene ring group, and the aromatic boron nitrogen-based narrow emission fluorescent material has a molecular structure as shown in formula (I):

[0043]

[0044] Wherein, D is the electron donating group.

[0045] The fluorescent material provided by the present application has an electron-donating group, a unique polyphenyl ring group and a multi-resonance rigid skeleton, wherein different electron-donating groups are introduced to the periphery of the aromatic boron nitrogen, so that there is spatial charge transfer, thereby improving the life of the light-emitting device; the polyphenyl ring group prevents the molecular π-π stacking, reduces the influence of aggregation-induced quenching (ACQ) and thus reduces energy loss; and the multi-resonance rigid skeleton has a high quantum yield and very high color purity, and a molecule with a donor-acceptor structure can be formed by combining the two. The multi-resonance structure containing the polyphenyl ring structure has a large plane and a large conjugated structure, which can enable the molecule to obtain a higher fluorescence quantum yield.

[0046] In some preferred embodiments, the aromatic boron nitrogen-containing narrow emission fluorescent material of the present application is selected from one of the following chemical structural formulas:

[0047]

[0048]

[0049] In some more preferred embodiments, the aromatic boron nitrogen-based narrow emission fluorescent material in the present application has one of the following chemical structural formulas:

[0050]

[0051] The present application also provides a method for preparing the above-mentioned aromatic boron nitrogen narrow emission fluorescent material. The method comprises the following steps:

[0052] S1. Synthesize the multi-resonance fragment DtCzB-Bpin, the structural formula of DtCzB-Bpin is shown below;

[0053]

[0054] S2. Carbazole and 2-bromo-4-iodotoluene are reacted by Ullmann reaction to obtain a bromine-substituted compound containing carbazole;

[0055] S3. The bromine-substituted compound containing carbazole and bromophenylboronic acid are reacted by Suzuki reaction to obtain a bromine-substituted compound containing a polyphenyl ring structure;

[0056] S4. The bromine-substituted compound containing a polyphenyl ring structure prepared in step S3 and the DtCzB-Bpin prepared in step S1 are reacted by Suzuki reaction to obtain a fluorescent material labeled 1;

[0057] S5. obtaining a polyphenyl ring-containing substituted compound by subjecting the cyclopentadienone compound to a carbon-oxygen addition reaction;

[0058] S6. The bromine-substituted compound containing a multi-benzene ring structure prepared in step S5 and the DtCzB-Bpin prepared in step S1 are reacted by Suzuki reaction to obtain a fluorescent material labeled 15.

[0059] In some preferred embodiments, the "synthesizing the multi-resonance fragment DtCzB-Bpin" in step S1 specifically comprises the following steps:

[0060] S11: Dissolve the raw materials 3,6-di-tert-butylcarbazole and cesium carbonate in N,N-dimethylformamide, stir for 2 h at 60°C under nitrogen protection, then add the raw material 2,6-difluorobromobenzene and stir for 12 h at 150°C. After the reaction is completed, cool, extract and recrystallize to obtain intermediate 1;

[0061]

[0062] S12: Dissolve the intermediate 1 in o-xylene, add n-butyl lithium below 0°C under a nitrogen atmosphere, and stir at room temperature for 3 hours; add boron tribromide below 0°C and stir at room temperature for 2 hours; then add N-diisopropylethylamine below 0°C and heat to 120°C and stir for 5 hours; after the reaction is completed, cool, extract, concentrate, separate and purify to obtain the intermediate 2;

[0063]

[0064] S13: The intermediate 2 and the raw material bis-pinacol diboron were dissolved in tetrahydrofuran, and dtbpy and the catalyst [Ir(COD)(OCH3)]2 were added. The mixture was heated to reflux at 70°C for 24 hours under a nitrogen atmosphere. After the reaction, DtCzB-Bpin was obtained by cooling, concentrating, separating and purifying.

[0065] In some preferred embodiments, the step S2 of "subjecting carbazole and 2-bromo-4-iodotoluene to an Ullmann reaction to obtain a bromine-substituted compound containing carbazole" specifically comprises the following steps: dissolving carbazole and 2-bromo-4-iodotoluene in N,N-dimethylformamide, adding 3M cesium carbonate, cuprous iodide and trimethylolethane, stirring for 48 hours under nitrogen protection and 110°C, and after the reaction is completed, cooling, extracting, concentrating, separating and purifying to obtain a bromine-substituted compound containing carbazole, and / or;

[0066] In some preferred embodiments, the step S3 of "subjecting the bromine-substituted compound containing carbazole and bromophenylboronic acid to Suzuki reaction to obtain a bromine-substituted compound containing a multi-benzene ring structure" specifically comprises the following steps: mixing the bromine-substituted compound containing carbazole and bromophenylboronic acid in step S2 and dissolving them in tetrahydrofuran, adding 2M potassium carbonate and tetrakistriphenylphosphine palladium, heating and refluxing at 70°C for 12h under a nitrogen atmosphere; after the reaction is completed, cooling, extracting, concentrating, separating and purifying to obtain a bromine-substituted compound containing a multi-benzene ring structure, and / or;

[0067] In some preferred embodiments, the step S4 of "subjecting the bromine-substituted compound containing a multi-benzene ring structure prepared in step S3 and the DtCzB-Bpin prepared in step S1 to obtain a fluorescent material labeled 1 through a Suzuki reaction" specifically includes the following steps: mixing and dissolving the bromine-substituted compound containing a multi-benzene ring structure in step S3 and DtCzB-Bpin in tetrahydrofuran, adding 2M potassium carbonate and tetrakistriphenylphosphine palladium, and heating and refluxing at 70°C for 12 hours under a nitrogen atmosphere; after the reaction is completed, cooling, extracting, concentrating, separating and purifying to obtain a fluorescent material compound labeled 1, and / or;

[0068] In some preferred embodiments, the step S5 of "subjecting a cyclopentadienone compound to a carbon-oxygen addition reaction to obtain a polyphenyl ring-containing substituted compound" specifically comprises the following steps: dissolving the cyclopentadienone compound and the bromoacetylene compound in o-xylene, stirring for 12 hours under nitrogen protection and 170°C, and after the reaction is completed, cooling, extracting, concentrating, separating and purifying to obtain a bromine-substituted compound containing a polyphenyl ring structure, and / or;

[0069] In some preferred embodiments, the step S6 of "using the tetraphenylethylene bromine-substituted compound containing a tetraphenyl structure and the DtCzB-Bpin prepared in step S5 to obtain a fluorescent material labeled 15 through a Suzuki reaction" specifically includes the following steps: mixing and dissolving the tetraphenylethylene bromine-substituted compound containing a polyphenyl ring structure and DtCzB-Bpin in tetrahydrofuran, adding 2M potassium carbonate and tetrakistriphenylphosphine palladium, and heating to reflux at 70°C for 12 hours under a nitrogen atmosphere; after the reaction is completed, cooling, extracting, concentrating, separating and purifying to obtain a fluorescent material labeled 15.

[0070] In some preferred embodiments, the molar ratio of the raw materials 2,6-difluorobromobenzene, 3,6-di-tert-butylcarbazole and cesium carbonate in step S11 is 1:(2.5-3):(3-4).

[0071] In some preferred embodiments, the molar ratio of the intermediate 1, n-butyl lithium, boron tribromide and N-diisopropylethylamine in step S12 is 1:(1-1.5):(1.5-2):(1.5-2).

[0072] In some preferred embodiments, the molar ratio of the intermediate 2 to the raw material bis-pinacolyl diboron in step S13 is 1:(1-1.5).

[0073] In some preferred embodiments, the molar ratio of carbazole to 2-bromo-4-iodotoluene in step S2 is 1:(1-1.2), and / or;

[0074] In some preferred embodiments, the molar ratio of bromophenylboronic acid to the bromine-substituted compound containing carbazole in step S3 is 1:(1-1.2), and / or;

[0075] In some preferred embodiments, the molar ratio of the cyclopentadienone compound to the bromoacetylene compound in step S5 is 1:(1-1.5), and / or;

[0076] In some preferred embodiments, the molar ratios of the bromine-substituted compound, DtCzB-Bpin and tetrakistriphenylphosphine palladium in steps S4 and S6 are independently (1-1.5):1:(0.03-0.05).

[0077] The present application also provides the use of the above-mentioned aromatic boron nitrogen-based narrow emission fluorescent material in luminescent materials or smart materials.

[0078] The present application also provides the use of the above-mentioned aromatic boron nitrogen-based narrow emission fluorescent material in the preparation of OLED devices.

[0079] The following will take the aromatic boron nitrogen narrow emission fluorescent materials M1 and M2 as examples to describe in detail the preparation method of the aromatic boron nitrogen narrow emission fluorescent material compound of formula (I).

[0080] Example 1

[0081] The applicant first synthesized a multi-resonance fragment, namely the compound DtCzB-Bpin, which was specifically prepared by the following method:

[0082] (1) Preparation of intermediate 1, its main chemical reaction equation is as follows:

[0083]

[0084] 3,6-di-tert-butylcarbazole (2.5eq, 20.06g) and cesium carbonate (3.0eq, 28g) were added to a 250ml dry two-necked bottle, 120ml DMF (N,N-dimethylformamide) was added, and N2 was replaced three times under stirring. Then, it was stirred at 60°C for 2h, and 2,6-difluorobromobenzene (1.0eq, 5.56g) was weighed and 10ml DMF was added to dilute it and injected into the two-necked bottle with a syringe, and then heated at 150°C for 10-12h. After the reaction was completed, the intermediate 1 was obtained by extraction, recrystallization, filtration and drying.

[0085] (2) Preparation of intermediate 2, its main chemical reaction equation is as follows:

[0086]

[0087] Add intermediate 1 (1.5mmol, 1.07g) to a 100ml dry two-necked flask, add 25ml o-xylene, and replace N2 three times under stirring. Then stir below 0℃ for 10min, carefully extract 1ml n-BuLi (2.5M) (2.5mmol) with a dried long needle and slowly inject it into the two-necked flask, stir for 10min and move to room temperature and stir for 3h. Lower the temperature to below 0℃, take 0.24mL BBr3 (2.5mmol) and slowly inject it into the reaction, stir for 10min and move to room temperature and stir for 2h, then move to a low-temperature reactor again, slowly add 0.7ml N,N-diisopropylethylamine at 0℃, stir for 10min and remove from the low-temperature reactor and heat to 120℃ and stir for 5h. After the reaction is completed, intermediate 2 is obtained by extraction, concentration, drying and separation.

[0088] (3) Preparation of DtCzB-Bpin, its main chemical reaction equation is as follows:

[0089]

[0090] The intermediate 2 (1.0eq, 5g) and the bis-pinacol diboron (1.1eq, 2g) were added to a 250ml dry single-mouth bottle, 81mg dtbpy and 30ml THF were added to the bottle, and finally 100mg [Ir (COD) (OCH3)]2 was added, and N2 was replaced three times under stirring. Then, the mixture was stirred at 70°C for 24h. After the reaction was completed, the compound DtCzB-Bpin was obtained by extraction, concentration, drying and separation.

[0091] Example 2

[0092] An aromatic boron nitrogen fluorescent material M1 is prepared by the following method:

[0093] (1) Preparation of intermediate 3

[0094] Weigh carbazole (1.00 g, 1 eq) and 2-bromo-4-iodotoluene (3.55 g, 2 eq) into a 100 ml dry single-mouth bottle, add cesium carbonate (5.85 g, 3 eq), cuprous iodide (0.114 g, 0.1 eg) and 1,1,1-ditrimethylolethane (0.072 g, 0.1 eg), and finally add 20 ml of ultra-dry N,N-dimethylformamide, stir for 48 h at 110 ° C under nitrogen protection, and after the reaction is completed, extract, concentrate, separate and purify to obtain intermediate 3, the main chemical reaction equation of which is as follows:

[0095]

[0096] (2) Preparation of intermediate 4

[0097] Weigh intermediate 3 (2g, 1eq) and 2-bromophenylboronic acid (1.43g, 1.2eq) into a 100ml dry single-mouth bottle, add 7.4ml of potassium carbonate aqueous solution (2M) and 20ml of ultra-dry tetrahydrofuran, and finally add tetrakistriphenylphosphine palladium (0.25g, 0.05eq). Stir at 70°C for 12h. After the reaction is completed, extract, dry, concentrate and separate to obtain intermediate 4; its main chemical reaction equation is as follows:

[0098]

[0099] (3) Preparation of Intermediate 5

[0100] Weigh intermediate 4 (0.66 g, 1.1 eq) and DtCzB-Bpin (0.76 g, 1 eq) into a two-necked flask, add 20 ml of tetrahydrofuran and 2 ml of potassium carbonate solution (2M), and finally add tetrakistriphenylphosphine palladium (0.056 g, 0.05 eq). Stir at 70°C for 12 h. After the reaction is completed, compound M1 is obtained by extraction, drying, concentration and separation; its main chemical reaction equation is as follows:

[0101]

[0102] (4) Preparation of Compound M1:

[0103] Weigh the intermediate 5 (0.3 g, 1 eq) into a two-necked flask, add 20 ml of dichloromethane, add 10 ml of ferric chloride nitromethane solution (2M) at -30°C and stir for 3 h. After the reaction is completed, extract, recrystallize, filter and dry to obtain compound M1, the main chemical reaction equation of which is as follows:

[0104]

[0105] Example 3

[0106] A fluorescent material M2 having a polybenzene ring structure is prepared by the following method:

[0107] (1) Preparation of intermediate 6

[0108] Weigh bromobenzyl (0.369 g, 1.1 eq) and DtCzB-Bpin (0.76 g, 1 eq) into a two-necked flask, add 10 ml of tetrahydrofuran and 1 ml of potassium carbonate solution (2 M), and finally add tetrakistriphenylphosphine palladium (0.056 g, 0.05 eq). Stir at 70 ° C for 12 h. After the reaction is completed, extract, dry, concentrate and separate to obtain intermediate 6. Its main chemical reaction equation is as follows:

[0109]

[0110] (2) Preparation of intermediate 7

[0111] Weigh intermediate 6 (0.5 g, 1 eq) and 3,4-bis(4-(tert-butyl)phenyl)-2,5-diphenylcyclopenta-2,4-diene-1-one (0.36 g, 1.1 eq) into a two-necked flask, and add 30 ml of o-xylene. Stir at 160°C for 12 h. After the reaction is completed, extract, dry, concentrate and separate to obtain intermediate 7. Its main chemical reaction equation is as follows:

[0112]

[0113] (3) Preparation of Compound M2

[0114] Weigh the intermediate 7 (0.3 g, 1 eq) into a two-necked flask, add 20 ml of dichloromethane, add 10 ml of ferric chloride nitromethane solution (2M) at -30°C and stir for 3 h. After the reaction is completed, extract, recrystallize, filter and dry to obtain compound M2, the main chemical reaction equation of which is as follows:

[0115]

[0116] Characterization and performance testing

[0117] The aromatic boron nitrogen fluorescent materials M1 and M2 obtained in Examples 2 and 3 were characterized and their performances were tested.

[0118] The test method is as follows:

[0119] Compound structure detection: using a Bruker 400MHz superconducting nuclear magnetic resonance spectrometer, the solvent is deuterated chloroform;

[0120] Mass spectrometry detection: M1 and M2 prepared in Examples 2 and 3 were dissolved in dichloromethane to prepare a solution with a concentration of 1 mg / mL, and mass spectrometry was performed using a liquid spectrometer LCMS-2020.

[0121] UV absorption spectrum detection: Shimadzu UV-visible spectrophotometer UV-2700 was used with a scanning range of 200 to 700 nm;

[0122] Emission spectrum detection: using a steady-state / transient fluorescence spectrometer (FLS980), the excitation wavelength is 365nm, under nitrogen protection, the test temperature is 300K.

[0123] The test results are as follows:

[0124] The molecular hydrogen spectrum of the aromatic boron nitrogen fluorescent material M1 prepared in Example 2 is as follows: Figure 1 As shown. It can be seen that: 1 HNMR (400MHz, Chloroform-d) δ9.07 (s, 2H), 8.39 (s, 2H), 8.21 (d, J = 9.4Hz, 4H), 7.95 (d, J = 8.7Hz, 2H), 7.84 (d, J = 6.3Hz, 2H), 7.67-7.57 (m, 4H), 7.46 (d, J = 8.2Hz, 3H), 7.32 (d, J = 8.1Hz, 1H), 7.06-6.08 (m, 5H), 2.70 (s, 3H), 1.56 (s, 15H), 1.42 (s, 18H), 1.25 (s, 4H). The molecular hydrogen spectrum peaks can correspond to the target product one by one, and the number is reasonable; from the mass spectrum ( Figure 2 ) can be seen in the figure, the relative molecular mass is 969.56, which is consistent with the relative molecular mass of the synthesized M1. Combining the above NMR and mass spectrometry results, it can be seen that the product obtained in Example 2 is M1.

[0125] The molecular hydrogen spectrum of the fluorescent material M2 having a multi-benzene ring structure prepared in Example 3 is as follows: Figure 3 As shown. It can be seen that: 1HNMR (400MHz, Methylene Chloride-d2)δ9.33(s,1H),8.91(d,J=1.9Hz,1H),8.86(dd,J=8.4,1.4Hz,1H),8 .80-8.74(m,2H),8.52(d,J=1.8Hz,1H),8.41-8.36(m,2H),8.19(d,J=1.9Hz,1H), 7.86(dd,J=8.8,2.1Hz,1H),7.69-7.59(m,3H),7.41(td,J=7.5,1.5Hz,1H),7.32 (dd,J=8.7,2.0Hz,1H),7.27(tt,J=7.5,1.3Hz,1H),7.22-7.14(m,2H),7.08(dt,J =7.6,1.7Hz,1H),6.99-6.91(m,2H),6.89-6.84(m,1H),6.70-6.61(m,2H),6.55( dd,J=6.2,2.5Hz,1H),6.31(dd,J=8.1,1.9Hz,1H),6.22-6.06(m,3H),5.96-5.89( m,2H),5.53(t,J=7.7Hz,1H),5.41(dd,J=7.9,1.5Hz,1H),5.32-5.30(m,1H),1.65(s,18H),1.58(s,18H),1.12(s,9H),1.01(s,9H). The molecular hydrogen spectrum peaks can correspond to the target product one by one, and the number is reasonable; from the mass spectrum ( Figure 4 ) can be seen in the figure, the relative molecular mass is 1207.55, which is consistent with the relative molecular mass of the synthesized M2. Combining the above NMR and mass spectrometry results, it can be seen that the product obtained in Example 3 is M2.

[0126] Using Shimadzu UV-2700 UV-visible spectrophotometer and FLS980 fluorescence instrument, the M1 prepared above was dissolved in toluene (TOL) solution to prepare 1×10 -3 mol / L stock solution, when testing, dilute to 1×10 -5 mol / L.

[0127] Figure 5 The M1 prepared in Example 2 is 1×10 -5 mol / L UV-visible absorption spectrum and fluorescence emission spectrum in toluene. Figure 5 It can be seen that the main absorption peak position of the molecule is 473nm, the main emission peak position is 491nm, and the half-peak width is only 35nm, achieving high color purity fluorescence emission.

[0128] Using Shimadzu UV-2700 UV-visible spectrophotometer and FLS980 fluorescence instrument, the M2 prepared above was dissolved in toluene (TOL) solution to prepare 1×10 -3 mol / L stock solution, when testing, dilute to 1×10 -5 mol / L.

[0129] Figure 6 The M2 prepared in Example 3 is 1×10 -5 mol / L UV-visible absorption spectrum and fluorescence emission spectrum in toluene. Figure 6 It can be seen that the main absorption peak position of the molecule is 510nm, the main emission peak position is 531nm, and the half-peak width is only 28nm, achieving high color purity fluorescence emission.

[0130] In summary, the narrow emission fluorescent material of the aromatic boron nitrogen type provided in the present application has narrow-band emission, high luminous intensity and delayed fluorescence, good thermal stability and good solubility, and can be used as a new type of soluble luminescent molecule with good performance and low cost. The fluorescent material has significant economic value in the preparation of luminescent materials, light-emitting devices or smart materials. The narrow emission fluorescent material of the aromatic boron nitrogen type can be widely used in the fields of color display and solid-state lighting, for the preparation of luminescent materials, light-emitting devices or smart materials, especially for the preparation of OLED devices.

[0131] At the same time, the present application realizes the controllable preparation of polyphenyl ring structure derivatives; the preparation cost is low, the raw material source is wide, large-scale production can be achieved, and it has broad commercial prospects.

[0132] In addition to the M1 and M2 compounds, the narrow emission fluorescent materials containing polybenzene structures in the present application include multiple aromatic boron nitrogen-based narrow emission fluorescent materials that are similar to the M1 and M2 structures and have unique multi-resonance rigid skeleton groups and polybenzene ring structures, wherein the polybenzene ring structure prevents molecular π-π stacking and has aggregation-induced luminescence enhancement performance, while the multi-resonance rigid skeleton group has the advantages of higher quantum yield and narrower half-peak width, which reduces the influence of aggregation-induced quenching and thus reduces energy loss, and a molecule with a donor-acceptor structure can be formed by combining the two. The multi-resonance structure containing polybenzene ring structures has a large plane and a larger conjugated structure, which can enable the molecule to obtain a high fluorescence quantum yield.

[0133] Therefore, the boron-containing narrow-band multi-resonance aromatic boron compounds provided in the present application can be used as luminescent materials or smart materials, and have good application prospects in the fields of full-color display and solid-state lighting.

[0134] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiments or examples are included in at least one embodiment or example of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0135] Although several embodiments of the present application have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present application, and that the scope of the present application is defined by the claims and their equivalents.

Claims

1. An aromatic boron nitrogen-based narrow emission fluorescent material, which can be used for organic small molecule optoelectronic functional materials, characterized in that: The invention comprises a multi-resonance rigid structure and an electron-donating group, and the narrow emission fluorescent material of the aromatic boron nitrogen type has a molecular structure as shown in formula (I): Wherein, D is the electron donating group.

2. The aromatic boron nitrogen narrow emission fluorescent material according to claim 1, characterized in that: The D is selected from one of the following structural formulas: Wherein, the R is selected from any one of H, Cl, Me or t-Bu.

3. The narrow emission fluorescent material of aromatic boron nitrogen type according to claim 2, characterized in that: The aromatic boron nitrogen narrow emission fluorescent material is selected from one of the following chemical structural formulas:

4. The aromatic boron nitrogen narrow emission fluorescent material according to claim 3, characterized in that: The boron-containing narrow-band multiple resonance aromatic boron compound has one of the following chemical structural formulas:

5. The method for preparing the narrow emission fluorescent material of arylboron nitrogen type according to claim 4, characterized in that: The following steps are involved: S1. Synthesize the multi-resonance fragment DtCzB-Bpin, the structural formula of DtCzB-Bpin is shown below; S2. Carbazole and 2-bromo-4-iodotoluene are reacted by Ullmann reaction to obtain a bromine-substituted compound containing carbazole; S3. The bromine-substituted compound containing carbazole and bromophenylboronic acid are reacted by Suzuki reaction to obtain a bromine-substituted compound containing a polyphenyl ring structure; S4. The bromine-substituted compound containing a polyphenyl ring structure prepared in step S3 and the DtCzB-Bpin prepared in step S1 are reacted by suzuki reaction to obtain a fluorescent material labeled 1; S5. obtaining a polyphenyl ring-containing substituted compound by subjecting the cyclopentadienone compound to a carbon-oxygen addition reaction; S6. The bromine-substituted compound containing a multi-benzene ring structure prepared in step S5 and the DtCzB-Bpin prepared in step S1 are reacted by Suzuki reaction to obtain a fluorescent material labeled 15.

6. The method for preparing the aromatic boron nitrogen narrow emission fluorescent material according to claim 5, characterized in that: The "synthesizing the multi-resonance fragment DtCzB-Bpin" in step S1 specifically comprises the following steps: S11: Dissolve the raw materials 3,6-di-tert-butylcarbazole and cesium carbonate in N,N-dimethylformamide, stir for 2 h at 60°C under nitrogen protection, then add the raw material 2,6-difluorobromobenzene and stir for 12 h at 150°C. After the reaction is completed, cool, extract and recrystallize to obtain intermediate 1; S12: Dissolve the intermediate 1 in o-xylene, add n-butyl lithium below 0°C under a nitrogen atmosphere, and stir at room temperature for 3 hours; add boron tribromide below 0°C and stir at room temperature for 2 hours; then add N-diisopropylethylamine below 0°C and heat to 120°C and stir for 5 hours; after the reaction is completed, cool, extract, concentrate, separate and purify to obtain the intermediate 2; S13: The intermediate 2 and the raw material bis-pinacol diboron were dissolved in tetrahydrofuran, and dtbpy and the catalyst [Ir(COD)(OCH3)]2 were added. The mixture was heated to reflux at 70°C for 24 hours under a nitrogen atmosphere. After the reaction, DtCzB-Bpin was obtained by cooling, concentrating, separating and purifying.

7. The method for preparing the aromatic boron nitrogen narrow emission fluorescent material according to claim 5, characterized in that: The step S2 of "subjecting carbazole and 2-bromo-4-iodotoluene to an Ullmann reaction to obtain a bromine-substituted compound containing carbazole" specifically comprises the following steps: dissolving carbazole and 2-bromo-4-iodotoluene in N,N-dimethylformamide, adding 3M cesium carbonate, cuprous iodide and trimethylolethane, stirring for 48 hours under nitrogen protection and 110°C, and after the reaction is completed, cooling, extracting, concentrating, separating and purifying to obtain a bromine-substituted compound containing carbazole, and / or; The step S3 of "subjecting the bromine-substituted compound containing carbazole and bromophenylboronic acid to Suzuki reaction to obtain a bromine-substituted compound containing a multi-benzene ring structure" specifically comprises the following steps: mixing the bromine-substituted compound containing carbazole and bromophenylboronic acid in step S2 and dissolving them in tetrahydrofuran, adding 2M potassium carbonate and tetrakistriphenylphosphine palladium, heating and refluxing at 70°C for 12h under a nitrogen atmosphere; after the reaction is completed, cooling, extracting, concentrating, separating and purifying to obtain a bromine-substituted compound containing a multi-benzene ring structure, and / or; The step S4 of "subjecting the bromine-substituted compound containing a multi-benzene ring structure prepared in step S3 and the DtCzB-Bpin prepared in step S1 to obtain a fluorescent material labeled 1 through a Suzuki reaction" specifically includes the following steps: mixing and dissolving the bromine-substituted compound containing a multi-benzene ring structure in step S3 and DtCzB-Bpin in tetrahydrofuran, adding 2M potassium carbonate and tetrakistriphenylphosphine palladium, and heating and refluxing at 70°C for 12 hours under a nitrogen atmosphere; after the reaction is completed, cooling, extracting, concentrating, separating and purifying to obtain a fluorescent material compound labeled 1, and / or; The step S5 of "subjecting a cyclopentadienone compound to a carbon-oxygen addition reaction to obtain a substituted compound containing multiple benzene rings" specifically comprises the following steps: dissolving the cyclopentadienone compound and the bromoacetylene compound in o-xylene, stirring for 12 hours under nitrogen protection and 170°C, and after the reaction is completed, cooling, extracting, concentrating, separating and purifying to obtain a bromine-substituted compound containing multiple benzene ring structures, and / or; The step S6 of "using the tetraphenylethylene bromine-substituted compound containing a tetraphenyl structure and the DtCzB-Bpin prepared in step S5 to obtain a fluorescent material labeled 15 through a Suzuki reaction" specifically includes the following steps: mixing and dissolving the tetraphenylethylene bromine-substituted compound containing a polyphenyl ring structure and DtCzB-Bpin in tetrahydrofuran, adding 2M potassium carbonate and tetrakistriphenylphosphine palladium, and heating and refluxing at 70°C for 12 hours under a nitrogen atmosphere; after the reaction is completed, cooling, extracting, concentrating, separating and purifying to obtain a fluorescent material labeled 15.

8. The method for preparing the arylborane-based narrow emission fluorescent material according to claim 6, characterized in that: The molar ratio of the raw materials 2,6-difluorobromobenzene, 3,6-di-tert-butylcarbazole and cesium carbonate in step S11 is 1:(2.5-3):(3-4), and / or; The molar ratio of the intermediate 1, n-butyl lithium, boron tribromide and N-diisopropylethylamine in step S12 is 1:(1-1.5):(1.5-2):(1.5-2), and / or; In step S13, the molar ratio of the intermediate 2 to the raw material bis-pinacolyl diboron is 1:(1-1.5).

9. The method for preparing the aromatic boron nitrogen narrow emission fluorescent material according to claim 5, characterized in that: The molar ratio of carbazole to 2-bromo-4-iodotoluene in step S2 is 1:(1-1.2), and / or; In step S3, the molar ratio of bromophenylboronic acid to the bromine-substituted compound containing carbazole is 1:(1-1.2), and / or; In step S5, the molar ratio of the cyclopentadienone compound to the bromoacetylene compound is 1:(1-1.5), and / or; The molar ratios of the bromine-substituted compound, DtCzB-Bpin and tetrakistriphenylphosphine palladium in steps S4 and S6 are independently (1-1.5):1:(0.03-0.05).

10. Use of the narrow emission fluorescent material of the aromatic boron nitrogen type according to claim 1, 2, 3 or 4 in light-emitting materials and in the preparation of OLED devices.

Images