Aryl boron-nitrogen compound with narrow-band green light emission as well as preparation method and application of aryl boron-nitrogen compound

Abstract

On the basis of a classical multi-resonance conjugated skeleton, through fusion with a spirofluorene bridge skeleton and introduction of a large-steric-hindrance protecting group, the Pi-Pi accumulation interaction between planar boron / nitride-containing molecules is effectively inhibited, and the aryl boron-nitrogen compound with narrow-band green light emission is obtained. The compound not only has a narrow emission band, high color purity, high fluorescence quantum yield and high luminous efficiency, but also can tolerate high-concentration doping, and has an anti-aggregation quenching effect. The design strategy of a multi-resonance material system is greatly expanded, a new choice is provided for preparing devices with high-concentration doping and high luminous efficiency, and the method is used for preparing luminescent materials and photoelectric luminescent devices.

Description

Technical Field

[0001] The present application relates to the technical field of organic light-emitting materials, and more specifically, to a preparation method and application of an aromatic boron nitrogen compound with narrow-band green light emission. Background Art

[0002] Organic light-emitting diodes (OLEDs) have attracted much attention in the fields of new display and lighting technologies due to their advantages such as high brightness, fast response, wide viewing angle, simple process and flexibility. Currently, OLED technology has been widely used in display panels of new lighting fixtures, smart phones and tablets, and will be further expanded to large-size display products such as TVs. As a new display technology that is developing rapidly and has high technical requirements, OLED needs to continue to research and innovate organic light-emitting materials to improve the luminous efficiency and service life of the device, thereby achieving higher performance.

[0003] Multiple resonance thermally activated delayed fluorescence (MR-TADF) materials have attracted much attention from the scientific research and industry circles due to their high color purity and high luminous efficiency. However, since such materials usually have a large rigid planar structure, they are prone to molecular aggregation, resulting in spectral broadening and a significant decrease in luminous efficiency. Therefore, such materials usually require extremely low doping concentrations (less than 1wt%) in devices to obtain optimal performance. However, due to the small Stokes shift of narrow-spectrum dyes, low concentration conditions often lead to incomplete energy transfer between the host and guest of the luminescent material, making it difficult to achieve the expected luminous efficiency. Further increasing the doping concentration will lead to a decrease in efficiency and color purity. Therefore, it is urgent to develop a MR-TADF material that can be doped at high concentrations and maintain high luminous efficiency and high color purity.

[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 an aromatic boron nitrogen compound with narrow-band green light emission, and to provide a MR-TADF material that can be doped with high concentration and has high luminous efficiency and high color purity for the fields of ultra-high-definition display and solid-state lighting.

[0006] Another object of the present application is to provide a method for preparing the above-mentioned aromatic boron nitrogen compound having narrow-band green light emission.

[0007] Another object of the present application is to provide an application of the above-mentioned aromatic boron nitrogen compound having narrow-band green light emission.

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

[0009] An aromatic boron nitrogen compound with narrow-band green light emission can be used for organic small molecule optoelectronic functional materials, and has a molecular structure shown in the following formula (1):

[0010]

[0011] Wherein, D is an electron donating or electron withdrawing group.

[0012] Preferably, in the aromatic boron nitrogen compound with narrow-band green light emission in the present application, D is selected from one of the following structural formulas:

[0013]

[0014] Wherein, said R is selected from H, CN, Me or t-Bu.

[0015] The present application also provides a method for preparing the above-mentioned narrow-band green light emitting aromatic boron nitrogen compound, comprising the following steps:

[0016] S1 Preparation of Intermediate 1

[0017] 1-Bromo-9-fluorenone, a compound containing D, tetrakis(triphenylphosphine)palladium and potassium carbonate were added to a reaction bottle in sequence. After nitrogen was replaced three times, ultra-dry N,N-dimethylformamide was added and refluxed under nitrogen. After the reaction was completed, the system was restored to room temperature, extracted and washed with dichloromethane and saturated brine, the organic phase was recovered and the solvent was removed, ethanol was added, heated and stirred, and filtered to obtain intermediate 1, whose structural formula is shown below:

[0018]

[0019] S2. Preparation of Intermediate 2

[0020] 1-Bromo-3-chloro-2,4-difluorobenzene, 3,6-di-tert-butylcarbazole and cesium carbonate were added to the reaction bottle in sequence. After nitrogen was replaced three times, ultra-dry N,N-dimethylformamide was added and refluxed under nitrogen. After the reaction was completed, the system was restored to room temperature, extracted and washed with dichloromethane and saturated brine, the organic phase was recovered and the solvent was removed, and ethanol was added and heated and stirred, and filtered to obtain intermediate 2, whose structural formula is shown below:

[0021]

[0022] S3. Preparation of Intermediate 3

[0023] The intermediate 2 obtained in step S2 is dissolved in tetrahydrofuran, and after nitrogen is replaced three times, n-butyl lithium is slowly added under low temperature stirring, and then the intermediate 1 obtained in step S1 is continuously added under low temperature stirring; after the reaction, water is added to quench the reaction, and the reaction is extracted and washed with dichloromethane and saturated brine, the organic phase is recovered and dried with anhydrous magnesium sulfate, and the solvent is removed by distillation under reduced pressure, and then the crude product is separated and purified by column chromatography to obtain intermediate 3, whose structural formula is shown below:

[0024]

[0025] S4. Preparation of aryl boron nitrogen compounds with narrow-band green emission

[0026] The intermediate 3 obtained in step S3 is dissolved in toluene, and after nitrogen is replaced three times, n-butyl lithium is slowly added under stirring, and then boron tribromide is continuously added under stirring, followed by N,N-diisopropylethylamine. After heating, stirring is continued until the reaction is completed; water is added to quench the reaction, and the mixture is extracted and washed with dichloromethane and saturated brine. The organic phase is recovered and dried with anhydrous magnesium sulfate, and the solvent is removed by distillation under reduced pressure. The crude product is then separated and purified by column chromatography to obtain an aromatic boron nitrogen compound with narrow-band green light emission.

[0027] Preferably, in step S1, the molar ratio of 1-bromo-9-fluorenone, the compound containing D, tetrakis(triphenylphosphine)palladium and potassium carbonate is 1:(1-2):(0.01-0.05):(2-3).

[0028] More preferably, in step S1, the reaction temperature is 110-150°C, and the reaction time is 24-36 hours.

[0029] Preferably, in step S2, the molar ratio of 1-bromo-3-chloro-2,4-difluorobenzene, 3,6-di-tert-butylcarbazole and cesium carbonate is 1:(2-3):(2-3).

[0030] More preferably, in step S2, the reaction temperature is 110-150°C, and the reaction time is 24-36 hours.

[0031] Preferably, in step S3, the molar ratio of intermediate 1 to intermediate 2 and n-butyl lithium is 1:(1-2):(1-2).

[0032] More preferably, in step S3, the reaction temperature is -100 to 50°C, and the reaction time is 12 to 24 hours.

[0033] The narrow-band green light emitting aromatic boron nitrogen compounds in the present application are used as light-emitting materials and light-emitting devices.

[0034] Compared with the prior art, the beneficial effects of this application are:

[0035] The aryl boron nitrogen compounds with narrow-band green light emission provided in the present application are based on the classic multi-resonance conjugated skeleton, by fusing with the spirofluorene bridge skeleton, and introducing a large steric protection group, which effectively inhibits the π-π stacking interaction between planar boron / nitride molecules, and obtains aryl boron nitrogen compounds with narrow-band green light emission. This type of compound not only has a narrow emission band, high color purity, high fluorescence quantum yield and high luminescence efficiency, but also can tolerate high concentration doping and has an anti-aggregation quenching effect, such asFigure 4 It greatly expands the design strategy of multi-resonance material systems, provides new options for the preparation of devices with high doping concentration and high luminescence efficiency, and is suitable for the preparation of luminescent materials and optoelectronic luminescent devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is the hydrogen nuclear magnetic resonance spectrum of compound A1 prepared in Example 1 of the present application;

[0037] Figure 2 The mass spectrum of compound A1 prepared in Example 1 of the present application;

[0038] Figure 3 The ultraviolet absorption spectrum and fluorescence emission spectrum of the compound A1 prepared in Example 1 of the present application in a 1.0×10-5M toluene solution;

[0039] Figure 4 This is a schematic diagram of the principles involved in this application. DETAILED DESCRIPTION

[0040] 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.

[0041] It should be noted that:

[0042] 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.

[0043] In the present application, unless otherwise specified, percentage (%) or part refers to the weight percentage or weight part relative to the composition.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] 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.

[0048] 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.

[0049] The present application provides an aromatic boron nitrogen compound with narrow-band green light emission, which can be used for organic small molecule optoelectronic functional materials, and has a molecular structure as shown in the following formula (1):

[0050]

[0051] Wherein, D is an electron donating or electron withdrawing group.

[0052] The aryl boron nitrogen compound with narrow-band green light emission provided by the present application is based on the classic multi-resonance conjugated skeleton, by fusing with the spirofluorene bridge skeleton, and introducing a large steric protection group, which effectively suppresses the π-π stacking interaction between planar boron / nitride molecules, and obtains an aryl boron nitrogen compound with narrow-band green light emission. This type of compound not only has a narrow emission band, high color purity, high fluorescence quantum yield and high luminous efficiency, but also can tolerate high concentration doping and has an anti-aggregation quenching effect. It greatly expands the design strategy of the multi-resonance material system, provides a new option for preparing devices with high concentration doping and high luminous efficiency, and is used in the preparation of luminescent materials and optoelectronic light-emitting devices.

[0053] The present application provides an aryl boron nitrogen compound with narrow-band green light emission, and its preparation method and application. The present application is based on the classic multi-resonance conjugated skeleton, by fusing with the spirofluorene bridge skeleton, and introducing a large steric protection group, effectively suppressing the π-π stacking interaction between planar boron / nitride molecules, and having an aryl boron nitrogen compound with narrow-band green light emission. This type of compound not only has a narrow emission band, high color purity, high fluorescence quantum yield and high luminescence efficiency, but also can tolerate high concentration doping and has an anti-aggregation quenching effect. It greatly expands the design strategy of multi-resonance material systems, provides a new option for preparing devices with high concentration doping and high luminescence efficiency, and is used in the preparation of luminescent materials and optoelectronic light-emitting devices.

[0054] In some preferred embodiments, in the narrow-band green light emitting aromatic boron nitrogen compound of the present application, D is selected from one of the following structural formulas:

[0055]

[0056] Wherein, R is selected from H, CN, Me or t-Bu

[0057] Therefore, specifically, the structural formula of the above-mentioned narrow-band green light emitting aromatic boron nitrogen compound is one of the following structures:

[0058]

[0059] Wherein, said R is selected from H, CN, Me or t-Bu.

[0060] Therefore, the present application is based on the classic multi-resonance conjugated skeleton, by fusing it with the spirofluorene bridge skeleton and introducing different large steric protection groups on the periphery, which effectively inhibits the π-π stacking interaction between planar boron / nitride molecules, and obtains aromatic boron nitrogen compounds with narrow-band green light emission.

[0061] In some more preferred embodiments, in the aromatic boron nitrogen compound with narrow-band green light emission in the present application, D is selected from one of the following structural formulas:

[0062]

[0063] wherein R is selected from H, CN, Me or t-Bu.

[0064] More specifically, the present application can construct the following aromatic boron nitrogen compounds with narrow-band green light emission:

[0065]

[0066] In some more preferred embodiments, D is selected from one of the following structural formulas:

[0067]

[0068] wherein R is selected from H, CN, Me or t-Bu.

[0069] For example, the following aromatic boron nitrogen narrow-band green light compound can be constructed:

[0070]

[0071] The above-constructed aromatic boron nitrogen narrow-band compound system is diverse and can achieve narrow-band emission, for example, green light emission.

[0072] The present application also provides a method for preparing the above-mentioned aromatic boron nitrogen compound having narrow-band green light emission. The method comprises the following steps:

[0073] S1. Preparation of Intermediate 1:

[0074] 1-Bromo-9-fluorenone, a compound containing D, tetrakis(triphenylphosphine)palladium and potassium carbonate are added to a reaction bottle in sequence, and after nitrogen is replaced three times, ultra-dry N,N-dimethylformamide is added, and reflux reaction is carried out under nitrogen conditions. After the reaction is completed, the system is returned to room temperature, extracted and washed with dichloromethane and saturated brine, the organic phase is recovered, the solvent is removed, ethanol is added, heated and stirred, and filtered to obtain intermediate 1;

[0075] S2. Preparation of Intermediate 2:

[0076] 1-Bromo-3-chloro-2,4-difluorobenzene, 3,6-di-tert-butylcarbazole and cesium carbonate were added to the reaction bottle in sequence, and the nitrogen was replaced three times, and then ultra-dry N,N-dimethylformamide was added, and reflux reaction was carried out under nitrogen conditions. After the reaction was completed, the system was restored to room temperature, and then extracted and washed with dichloromethane and saturated brine. After the organic phase was recovered and the solvent was removed, ethanol was added, heated and stirred, and filtered to obtain intermediate 2, whose structural formula is shown below;

[0077]

[0078] S3. Preparation of Intermediate 3:

[0079] The intermediate 2 obtained in step S2 is dissolved in tetrahydrofuran, and after nitrogen is replaced three times, n-butyl lithium is slowly added under low temperature stirring, and then the intermediate 1 obtained in step S1 is continuously added under low temperature stirring; after the reaction, water is added to quench the reaction, and the reaction is extracted and washed with dichloromethane and saturated brine, the organic phase is recovered and dried with anhydrous magnesium sulfate, and the solvent is removed by distillation under reduced pressure, and then the crude product is separated and purified by column chromatography to obtain intermediate 3, whose structural formula is shown below;

[0080]

[0081] S4. Preparation of aryl boron nitrogen compounds with narrow-band green emission:

[0082] The intermediate 3 obtained in step S3 is dissolved in toluene, and after nitrogen is replaced three times, n-butyl lithium is slowly added under stirring, and then boron tribromide is continuously added under stirring, followed by N,N-diisopropylethylamine. After heating, stirring is continued until the reaction is completed; water is added to quench the reaction, and the mixture is extracted and washed with dichloromethane and saturated brine. The organic phase is recovered and dried with anhydrous magnesium sulfate, and the solvent is removed by distillation under reduced pressure. The crude product is then separated and purified by column chromatography to obtain an aromatic boron nitrogen compound with narrow-band green light emission.

[0083] In some preferred examples, the molar ratio of 1-bromo-9-fluorenone, the compound containing D, tetrakis(triphenylphosphine)palladium and potassium carbonate described in step S1 of the method for preparing aromatic boron nitrogen compounds with narrow-band green light emission in this patent is 1:(1-2):(0.01-0.05):(2-3), the reaction temperature is 110-150°C, and the reaction time is 24-36h.

[0084] In some preferred embodiments, in step S2 of the method for preparing an aromatic boron nitrogen compound with narrow-band green light emission in the present patent, the molar ratio of 1-bromo-3-chloro-2,4-difluorobenzene, 3,6-di-tert-butylcarbazole and cesium carbonate is 1:(2-3):(2-3), the reaction temperature is 110-150°C, and the reaction time is 24-36h.

[0085] In some preferred examples, in step S3 of the method for preparing aromatic boron nitrogen compounds with narrow-band green light emission in the present patent, the molar ratio of intermediate 1 to intermediate 2 and n-butyl lithium is 1:(1-2):(1-2), the reaction temperature is -100-50°C, and the reaction time is 12-24h.

[0086] The present application also provides an application of an aromatic boron nitrogen compound having narrow-band green light emission as a light-emitting material, a light-emitting device or a smart material.

[0087] The preparation method of the arylboron nitrogen compound having narrow-band green light emission of formula (I) will be described in detail below.

[0088] Example 1

[0089] This embodiment provides an aromatic boron nitrogen compound with narrow-band green light emission, the structural formula of which is shown in A1:

[0090]

[0091] The preparation method of the compound is as follows:

[0092] S1. Preparation of intermediate 1:

[0093] 1-Bromo-9-fluorenone, 9-phenyl-9H-carbazole-3-boronic acid naphthalene ester, tetrakis(triphenylphosphine)palladium and potassium carbonate were added to the reaction bottle in sequence, and the nitrogen was replaced three times, and then ultra-dry N,N-dimethylformamide was added, and the reaction was refluxed under nitrogen. After the reaction was completed, the system was restored to room temperature, and then extracted and washed with dichloromethane and saturated brine, and the organic phase was recovered to remove the solvent, and then ethanol was added, heated and stirred, and filtered to obtain intermediate 1;

[0094]

[0095] The reaction equation in the above preparation method is as follows:

[0096]

[0097] S2. Preparation of Intermediate 2:

[0098] 1-Bromo-3-chloro-2,4-difluorobenzene, 3,6-di-tert-butylcarbazole and cesium carbonate were added to the reaction bottle in sequence, and the nitrogen was replaced three times, and then ultra-dry N,N-dimethylformamide was added, and reflux reaction was carried out under nitrogen conditions. After the reaction was completed, the system was restored to room temperature, and then extracted and washed with dichloromethane and saturated brine. After the organic phase was recovered and the solvent was removed, ethanol was added, heated and stirred, and filtered to obtain intermediate 2, whose structural formula is shown below;

[0099]

[0100] The reaction equation in the above preparation method is as follows:

[0101]

[0102] S3. Preparation of Intermediate 3:

[0103] The intermediate 2 obtained in step S2 is dissolved in tetrahydrofuran, and after nitrogen is replaced three times, n-butyl lithium is slowly added under low temperature stirring, and then the intermediate 1 obtained in step S1 is continuously added under low temperature stirring; after the reaction, water is added to quench the reaction, and the reaction is extracted and washed with dichloromethane and saturated brine, the organic phase is recovered and dried with anhydrous magnesium sulfate, and the solvent is removed by distillation under reduced pressure, and then the crude product is separated and purified by column chromatography to obtain intermediate 3, whose structural formula is shown below;

[0104]

[0105] The reaction equation in the above preparation method is as follows:

[0106]

[0107] Preparation of S4.A1:

[0108] The intermediate 3 obtained in step S3 was dissolved in toluene, and after nitrogen was replaced three times, n-butyl lithium was slowly added under stirring, and then boron tribromide was continuously added under stirring, and then N, N-diisopropylethylamine was added, and stirring was continued until the reaction was completed after heating; water was added to quench the reaction, and the reaction was extracted and washed with dichloromethane and saturated brine, and the organic phase was recovered and dried over anhydrous magnesium sulfate, and the solvent was removed by distillation under reduced pressure, and then the crude product was separated and purified by column chromatography to obtain an aryl boron nitride having narrow-band green light emission.

[0109] The structural formula of the final compound A1 is as follows:

[0110]

[0111] The reaction equation in the above preparation method is as follows:

[0112]

[0113] Performance Testing

[0114] The narrow-band green light emitting aromatic boron nitrogen compound A1 prepared in Example 1 was characterized and its performance tested.

[0115] The test method is as follows:

[0116] Compound structure detection: using a Bruker 400MHz superconducting nuclear magnetic resonance spectrometer, the solvent is deuterated chloroform or deuterated dimethyl sulfoxide;

[0117] Mass spectrometry detection: A1 and A2 prepared in Example 1 and Example 2 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.

[0118] UV absorption spectrum detection: Shimadzu UV-visible spectrophotometer UV-2700 was used with a scanning range of 200 to 450 nm;

[0119] Emission spectrum detection: using a steady-state / transient fluorescence spectrometer (FLS980), the excitation wavelength is 310nm, under nitrogen protection, the test temperature is 300K.

[0120] The test results are as follows:

[0121] The hydrogen nuclear magnetic resonance spectrum of the aromatic boron nitrogen compound A1 with narrow-band green light emission prepared in Example 1 is as follows: Figure 1 As shown. Figure 1It can be seen that: 1H NMR (400MHz, Chloroform-d) δ8.97–8.87 (m, 1H), 8.70–8.63 (m, 1H), 8.44 (d, J = 1.9 Hz, 1H), 8.28–8.19 (m, 2H), 8.03–7.98 (m, 2H), 7.92 (d, J = 8.7 Hz, 1H), 7.86–7.79 (m, 2H), 7.58 (dd, J = 8.8, 2.1 Hz, 1H), 7.53–7.44 (m, 3H), 7.27 (d, J = 7.2 Hz, 2H) ,7.22(dd,J=7.5,1.2Hz,2H),7.11–7.05(m,3H),7.02–6.95(m,4H),6.87(d,J=8.2Hz,1H),6.66(d,J=1.4Hz,1H),6.51(d,J=1.6Hz,1H),6.19(d,J=8.2Hz,1H),6.03(dd,J=8.3,1.7Hz,1H),1.71(s,9H),1.52(s,9H),1.42(s,9H),1.35(s,9H). The peaks of the hydrogen spectrum of the NMR molecule can correspond to the target product one by one, and the quantity is reasonable;

[0122] The mass spectrum of compound A1 prepared in Example 1 of the present application is as follows Figure 2 As shown. Figure 2 As can be seen in the figure, the relative molecular mass is 1044.54, which is consistent with the relative molecular mass of the synthesized A1. Combining the results of the above nuclear magnetic resonance hydrogen spectrum and mass spectrum, it can be seen that the product prepared in Example 1 is A1.

[0123] Using Shimadzu UV-2700 ultraviolet visible spectrophotometer, A1 prepared in Example 1 was dissolved in toluene solution to prepare 1×10 -3 mol / L stock solution, and then diluted to 1×10 -5 mol / L solution was tested.

[0124] Figure 3 A1 prepared in Example 1 is 1×10 -5 mol / L UV-visible absorption spectrum in toluene. Figure 3 It can be seen that the main absorption peak position of A1 is 500nm.

[0125] Using fluorescence emission spectroscopy: FLS980 fluorescence instrument, the A1 prepared in Example was dissolved in toluene solution to prepare 1×10 -3 mol / L stock solution, diluted to 1×10 -5 mol / L solution.

[0126] Figure 3A1 prepared in Example 1 is 1×10 -5 mol / L toluene solution. Figure 3 It can be seen that the main emission peak positions of A1 are 515nm, both of which are green light emissions, and the half-peak width of A1 is 23nm, which means that narrow-band emission is achieved. That is, the aromatic boron nitrogen compound system with narrow-band green light emission provided by the present application is diverse and can achieve spectral band emission, for example, green light emission can be achieved.

[0127] In summary, the aryl boron nitrogen compound with narrow-band green light emission provided by the present application embodies narrow-band emission and can be used as a new type of luminescent molecule with high color purity, high fluorescence quantum yield and high luminescence efficiency. The aryl boron nitrogen compound with narrow-band green light emission has great application potential in the preparation of luminescent materials, luminescent devices or smart materials, and has good application prospects in the fields of full-color display and solid-state lighting.

[0128] At the same time, the present application realizes the controllable preparation of aromatic boron nitrogen compounds with narrow-band green light emission; the preparation cost is low, the raw material source is wide, large-scale production can be achieved, and it has broad commercial prospects.

[0129] The aromatic boron nitrogen compound with narrow-band green light emission provided in the present application is based on the classic multi-resonance conjugated skeleton, by fusing with the spirofluorene bridge skeleton, and introducing a large steric protection group, which effectively inhibits the π-π stacking interaction between planar boron / nitride molecules, and obtains an aromatic boron nitrogen compound with narrow-band green light emission. This type of compound not only has a narrow emission band, high color purity, high fluorescence quantum yield and high luminescence efficiency, but also can tolerate high concentration doping and has an anti-aggregation quenching effect, such as Figure 4 It greatly expands the design strategy of multi-resonance material systems, provides new options for the preparation of devices with high doping concentration and high luminescence efficiency, and is used in the preparation of luminescent materials and optoelectronic luminescent devices.

[0130] Therefore, the aromatic boron nitrogen compound with narrow-band green light emission provided in the present application can be used as a luminescent material or smart material, and has good application prospects in the fields of full-color display and solid-state lighting.

[0131] 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.

[0132] 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 compound with narrow-band green light emission, which can be used for organic small molecule optoelectronic functional materials, characterized in that: It has a molecular structure as shown in the following formula (1): Wherein, D is an electron donating or electron withdrawing group.

2. The aryl boron nitrogen compound having narrow-band green light emission according to claim 1, characterized in that: The D is selected from one of the following structural formulas: Wherein, said R is selected from H, CN, Me or t-Bu.

3. The method for preparing the narrow-band green light emitting aromatic boron nitrogen compound according to claim 1 or 2, characterized in that: The following steps are involved: S1. Preparation of Intermediate 1 1-Bromo-9-fluorenone, a compound containing D, tetrakis(triphenylphosphine)palladium and potassium carbonate were added to a reaction bottle in sequence. After nitrogen was replaced three times, ultra-dry N,N-dimethylformamide was added and refluxed under nitrogen. After the reaction was completed, the system was restored to room temperature, extracted and washed with dichloromethane and saturated brine, the organic phase was recovered and the solvent was removed, ethanol was added, heated and stirred, and filtered to obtain intermediate 1, whose structural formula is shown below: S2. Preparation of Intermediate 2 1-Bromo-3-chloro-2,4-difluorobenzene, 3,6-di-tert-butylcarbazole and cesium carbonate were added to the reaction bottle in sequence. After nitrogen was replaced three times, ultra-dry N,N-dimethylformamide was added and refluxed under nitrogen. After the reaction was completed, the system was restored to room temperature, extracted and washed with dichloromethane and saturated brine, the organic phase was recovered and the solvent was removed, and ethanol was added and heated and stirred, and filtered to obtain intermediate 2, whose structural formula is shown below: S3. Preparation of Intermediate 3 The intermediate 2 obtained in step S2 is dissolved in tetrahydrofuran, and after nitrogen is replaced three times, n-butyl lithium is slowly added under low temperature stirring, and then the intermediate 1 obtained in step S1 is continuously added under low temperature stirring; after the reaction, water is added to quench the reaction, and the reaction is extracted and washed with dichloromethane and saturated brine, the organic phase is recovered and dried with anhydrous magnesium sulfate, and the solvent is removed by distillation under reduced pressure, and then the crude product is separated and purified by column chromatography to obtain intermediate 3, whose structural formula is shown below: S4. Preparation of aryl boron nitrogen compounds with narrow-band green emission The intermediate 3 obtained in step S3 is dissolved in toluene, and after nitrogen is replaced three times, n-butyl lithium is slowly added under stirring, and then boron tribromide is continuously added under stirring, followed by N,N-diisopropylethylamine. After heating, stirring is continued until the reaction is completed; water is added to quench the reaction, and the mixture is extracted and washed with dichloromethane and saturated brine. The organic phase is recovered and dried with anhydrous magnesium sulfate, and the solvent is removed by distillation under reduced pressure. The crude product is then separated and purified by column chromatography to obtain an aromatic boron nitrogen compound with narrow-band green light emission.

4. The method for preparing the narrow-band green light emitting aromatic boron nitrogen compound according to claim 3, characterized in that: In step S1, the molar ratio of 1-bromo-9-fluorenone, the compound containing D, tetrakis(triphenylphosphine)palladium and potassium carbonate is 1:(1-2):(0.01-0.05):(2-3).

5. The method for preparing the narrow-band green light emitting aromatic boron nitrogen compound according to claim 4, characterized in that: In step S1, the reaction temperature is 110-150°C, and the reaction time is 24-36 hours.

6. The method for preparing the narrow-band green light emitting aromatic boron nitrogen compound according to claim 3, characterized in that: In step S2, the molar ratio of 1-bromo-3-chloro-2,4-difluorobenzene, 3,6-di-tert-butylcarbazole and cesium carbonate is 1:(2-3):(2-3).

7. The method for preparing the narrow-band green light emitting aromatic boron nitrogen compound according to claim 6, characterized in that: In step S2, the reaction temperature is 110-150°C, and the reaction time is 24-36 hours.

8. The method for preparing the narrow-band green light emitting aromatic boron nitrogen compound according to claim 3, characterized in that: In step S3, the molar ratio of the intermediate 1 to the intermediate 2 and n-butyl lithium is 1:(1-2):(1-2).

9. The method for preparing the narrow-band green light emitting aromatic boron nitrogen compound according to claim 3, characterized in that: In step S3, the reaction temperature is -100 to 50°C, and the reaction time is 12 to 24 hours.

10. Use of the aryl boron nitrogen compound having narrow-band green light emission according to claim 1 or 2 as a light-emitting material or a light-emitting device.

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