Spirofluorene-based anthracene derivative blue luminescent material as well as preparation method and application thereof

Abstract

The invention provides an anthracene derivative blue light-emitting material based on spirofluorene as well as preparation and application of the anthracene derivative blue light-emitting material, and the anthracene derivative blue light-emitting material is named as 4-(10-(spiro [fluorenone-9, 8 '-indole [3, 2, 1-de] acridine]-4-yl) anthracene-9-yl) benzonitrile and 4-(10-(10-phenyl-10H-spiro [acridine-9. 9-fluorenone]-4'-yl) anthracene-9-yl) benzonitrile. Anthracene with efficient fluorescence quantum efficiency is used as a parent body, benzene cyanogen with electron withdrawing property and 4-bromo-spiro [fluorene-9, 8 '-[8H] indole [3, 2, 1-DE] acridine] and 4'-bromine-10-phenyl-10H-spiro [acridine-9, 9 '-fluorene] with electron donating property are linked, so that the injection and transmission of current carriers are more balanced, and the performance of the device is further improved; the spirofluorene structure can interrupt conjugation, maintain efficient blue light emission of anthracene, inhibit close accumulation among molecules in an aggregation state, obtain high fluorescence quantum efficiency and efficiently emit blue light in an organic solvent. The anthracene material has remarkable economic value in the application aspects of preparing a luminescent material, a luminescent device or an intelligent material and the like.

Description

Technical Field

[0001] The present application relates to the technical field of organic optoelectronic materials and their optoelectronic device applications, and more specifically, to an anthracene derivative blue light-emitting material based on spirofluorene, and its preparation method and application. Background Art

[0002] Organic light-emitting diodes (OLEDs) have great application potential in the fields of flat panel displays, smartphones, and solid-state lighting due to their advantages such as light weight, good flexibility, wide operating temperature range, short response time, high brightness and contrast, and wide viewing angle.

[0003] The light-emitting material is the substance responsible for emitting light in an OLED device. Therefore, properties such as the luminous efficiency, luminous lifetime, and luminous color of the light-emitting material will affect the performance of the OLED device. As a light-emitting material in an OLED, it should meet the following conditions: 1) Have a high fluorescence quantum yield and no severe aggregation-caused quenching (ACQ) effect to ensure high device efficiency; 2) Have high thermal stability and chemical stability to ensure that the OLED device can be prepared by chemical deposition method and will not react with the electrode and carrier transport materials; 3) Be easy to form a dense amorphous film and not easy to crystallize; 4) Have appropriate energy levels to ensure appropriate emission wavelengths; 5) Have good electrical conductivity and certain carrier transport capabilities.

[0004] Since the anthracene-based light-emitting materials in small molecule organic electroluminescent devices form π-π stacking in the aggregated state, resulting in the quenching of their fluorescence, thereby reducing the device efficiency. At the same time, blue light-emitting materials generally have problems of unbalanced carrier injection and migration and low fluorescence quantum efficiency, which limit the large-scale application of such light-emitting materials in the field of light-emitting device preparation.

[0005] Therefore, it is an urgent technical problem for those skilled in the art to develop an organic electroluminescent material that simultaneously has good carrier transport capabilities and a high fluorescence quantum yield in the aggregated state.

[0006] Application Content

[0007] The technical problem to be solved by this application is to overcome the problem that existing anthracene-based luminescent materials form π-π stacking in the aggregated state, resulting in the quenching of their fluorescence and thus reducing their fluorescence quantum yield. A blue luminescent material based on spirofluorene-anthracene derivatives is provided. By using the high fluorescence quantum efficiency characteristic of anthracene as a bridge and leveraging the electron-withdrawing property of benzonitrile and the electron-donating properties of carbazole or triphenylamine groups, the injection and transport of carriers are made more balanced, improving the device performance. The spirofluorene structure can interrupt conjugation, maintain the efficient blue luminescence of anthracene, and at the same time inhibit the close packing between molecules in the aggregated state, obtaining a high fluorescence quantum efficiency. It can also emit efficient blue light in organic solvents. This blue luminescent material based on spirofluorene-anthracene derivatives has significant economic value in applications such as preparing luminescent materials, light-emitting devices, or intelligent materials.

[0008] Another object of this application is to provide a preparation method of a blue luminescent material based on spirofluorene-anthracene derivatives.

[0009] The above object of this application is achieved through the following technical solutions:

[0010] A blue luminescent material based on spirofluorene-anthracene derivatives has the following structural formula:

[0011]

[0012] Among them, R is selected from one of the following structural formulas a to q:

[0013]

[0014] Preferably, the blue luminescent material based on spirofluorene-anthracene derivatives in this application has the structural formulas shown in (I) and (II) below:

[0015]

[0016] This application also provides a preparation method of the above blue luminescent material based on spirofluorene-anthracene derivatives, including the following steps:

[0017] S1. React 4-cyanophenylboronic acid and 9,10-dibromoanthracene under the action of the catalyst tetrakis(triphenylphosphine)palladium to obtain 4-(10-bromoanthracen-9-yl)benzonitrile (i.e., compound 1). The corresponding chemical reaction equation for this step is as follows:

[0018]

[0019] S2. React 4-(10-bromoanthracen-9-yl)benzonitrile prepared in S1 with bis(pinacolato)diboron in the presence of the catalyst bis(triphenylphosphine)palladium dichloride to obtain 4-(10-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)anthracen-9-yl)benzonitrile (i.e., Compound 1). The chemical reaction equation corresponding to this step is as follows:

[0020]

[0021] S3. React 4-bromo-spiro[fluorene-9,8'-[8H]indolo[3,2,1-de]acridine] and 4'-bromo-10-phenyl-10H-spiro[acridine-9,9'-fluorene] with 4-(10-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)anthracen-9-yl)benzonitrile prepared in step S2 in the presence of the catalyst tetrakis(triphenylphosphine)palladium to obtain the target products 4-(10-(spiro[fluorenone-9,8'-indolo[3,2,1-de]acridin]-4-yl)anthracen-9-yl)benzonitrile shown in formula (I) and 4-(10-(10-phenyl-10H-spiro[acridine-9.9-fluorenone]-4'-yl)anthracen-9-yl)benzonitrile shown in formula (II) (i.e., Compound SCZ-4AnCN or Compound STPA-4AnCN). The chemical reaction equation corresponding to this step is as follows;

[0022] ;

[0023] or

[0024]

[0025] Preferably, the molar ratio of 9,10-dibromoanthracene, 4-cyanophenylboronic acid, and tetrakis(triphenylphosphine)palladium in step S1 is 1 - 1.5:1 - 1.5:0.05 - 0.10. More preferably, the molar ratio of 9,10-dibromoanthracene, 4-cyanophenylboronic acid, and tetrakis(triphenylphosphine)palladium in step S1 is 1:1:0.05.

[0026] Preferably, the solvent for the reaction in step S1 is anhydrous toluene.

[0027] Preferably, the reaction in step S1 is catalyzed by a strong base, and the strong base is potassium carbonate or sodium carbonate.

[0028] Preferably, the reaction conditions in step S1 are heating under reflux under the protection of an inert gas.

[0029] Preferably, the inert gas in step S1 is nitrogen, argon, or helium.

[0030] More preferably, the inert gas in step S1 is nitrogen.

[0031] Preferably, the reaction temperature is 90 - 100 °C; the reaction time is 12 - 24 h; more preferably, the reaction temperature is 95 °C; the reaction time is 12 h.

[0032] Preferably, the treatment in step S1 is cooling, extraction, drying, concentration, and separation. After cooling the reaction solution to room temperature, the obtained mixture is extracted three times with dichloromethane, and the organic phases obtained from the three extractions are combined; then it is dried with anhydrous sodium sulfate, and the organic phase is concentrated under reduced pressure to obtain a crude product; finally, silica gel column chromatography is carried out using dichloromethane and petroleum ether as eluents to separate 4-(10-bromoanthracen-9-yl)benzonitrile.

[0033] Preferably, the molar ratio of 4-(10-bromoanthracen-9-yl)benzonitrile, bis(pinacolato)diboron, and bis(triphenylphosphine)palladium dichloride in step S2 is 1 - 1.5:1.5 - 2:0.05 - 0.1; more preferably, the molar ratio of 4-(10-bromoanthracen-9-yl)benzonitrile, bis(pinacolato)diboron, and bis(triphenylphosphine)palladium dichloride in step S2 is: 1:1.5:0.05.

[0034] Preferably, the solvent for the reaction in step S2 is 1,4-dioxane.

[0035] Preferably, the inert gas in step S2 is nitrogen, argon, or helium. More preferably, the inert gas in step S2 is nitrogen.

[0036] Preferably, the reaction temperature in step S2 is 95 - 105 °C, and the reaction time is 12 - 36 h. More preferably, the reaction temperature in step S2 is 100 °C, and the reaction time is 24 h.

[0037] Preferably, the treatment in step S2 is extraction, washing, drying, concentration, and separation. After the reaction is completed, it is extracted three times with dichloromethane, the organic phases obtained from the three extractions are combined, the organic phase is dried with anhydrous sodium sulfate, and the organic phase is concentrated under reduced pressure to obtain a crude product; finally, silica gel column chromatography is carried out using dichloromethane and petroleum ether as eluents to separate 4-(10-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)anthracen-9-yl)benzonitrile.

[0038] Preferably, in step S3, the molar ratio of 4-bromo-spiro[fluorene-9,8'-[8H]indolo[3,2,1-de]acridine] or 4'-bromo-10-phenyl-10H-spiro[acridine-9,9'-fluorene], 4-(10-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)anthracen-9-yl)benzonitrile, and tetrakis(triphenylphosphine)palladium is 1 to 1.5:1 to 1.5:0.05 to 0.10. More preferably, in step S3, the molar ratio of 4-bromo-spiro[fluorene-9,8'-[8H]indolo[3,2,1-de]acridine] or 4'-bromo-10-phenyl-10H-spiro[acridine-9,9'-fluorene], 4-(10-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)anthracen-9-yl)benzonitrile, and tetrakis(triphenylphosphine)palladium is 1:1.2:0.05.

[0039] Preferably, the solvent for the reaction in step S3 is anhydrous toluene.

[0040] Preferably, the reaction in step S3 is catalyzed by a strong base; the strong base is potassium carbonate or sodium carbonate.

[0041] Preferably, the conditions for the reaction in step S3 are heating under reflux under the protection of an inert gas. Preferably, the inert gas in step S3 is nitrogen, argon, or helium. More preferably, the inert gas in step S3 is nitrogen. Preferably, the reaction temperature is 90 to 100 °C; the reaction time is 12 to 24 h; more preferably, the reaction temperature is 95 °C; the reaction time is 12 h.

[0042] Preferably, the treatment in step S3 is cooling, extraction, drying, concentration, and separation. After cooling the reaction solution to room temperature, the resulting mixture is extracted three times with dichloromethane, and the organic phases obtained from the three extractions are combined; then it is dried with anhydrous sodium sulfate, and the organic phase is concentrated under reduced pressure to obtain a crude product; finally, 4-(10-(10-phenyl-10H-spiro[acridine-9.9-fluorenone]-2'-yl)anthracen-9-yl)benzonitrile and 4-(10-(spiro[fluorenone-9,8'-indolo[3,2,1-de]acridine]-2-yl)anthracen-9-yl)benzonitrile are separated by silica gel column chromatography using dichloromethane and petroleum ether as eluents.

[0043] Compared with the prior art, the beneficial effects of the technical solution of the present application are as follows:

[0044] This application uses the high fluorescence quantum efficiency property of anthracene as a bridge. By virtue of the electron-withdrawing property of benzonitrile and the electron-donating properties of carbazole or triphenylamine groups, the injection and transport of carriers are made more balanced, improving the device performance. The spirofluorene structure can interrupt conjugation, maintaining the efficient blue emission of anthracene. At the same time, it can inhibit the close packing between molecules in the aggregated state, obtaining a high fluorescence quantum efficiency (for example, the fluorescence quantum yield of SCZ-4AnCN is 95%). It can also emit efficient blue light in organic solvents. This spirofluorene-based anthracene derivative blue light-emitting material has significant economic value in applications such as preparing light-emitting materials, light-emitting devices, or intelligent materials.

[0045] Meanwhile, the preparation process of the compounds described in this application is simple, convenient, and can be prepared in large-scale batches, which is conducive to industrial production and the popularization of its applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 1H NMR spectrum of the compound SCZ-4AnCN prepared in Example 1 1

[0047] Figure 2 1H NMR spectrum of the compound STPA-4AnCN prepared in Example 2 1

[0048] Figure 3 Mass spectrum of the compound SCZ-4AnCN prepared in Example 1

[0049] Figure 4 Mass spectrum of the compound STPA-4AnCN prepared in Example 2

[0050] Figure 5 UV-visible absorption spectrum and fluorescence emission spectrum of the compounds prepared in Examples 1 and 2 in toluene solution

[0051] Figure 6 UV-visible absorption spectrum and fluorescence emission spectrum of the compounds prepared in Examples 1 and 2 in thin films

[0052] Figure 7 Cyclic voltammogram of the compounds prepared in Examples 1 and 2

[0053] Figure 8 Fluorescence quantum yield graph of the compound SCZ-4AnCN prepared in Example 1

[0054] Figure 9 Fluorescence quantum yield graph of the compound STPA-4AnCN prepared in Example 2 DETAILED DESCRIPTION OF THE EMBODIMENTS

[0055] ​​The following further elaborates on the present application in combination with specific embodiments. The embodiments are only used to explain the present application and are not intended to limit the scope of the present application. Unless otherwise specified, the test methods used in the following embodiments are all conventional methods; the materials, reagents, etc. used, unless otherwise specified, are reagents and materials that can be obtained from commercial channels.

[0056] The present application uses the high fluorescence quantum efficiency characteristic of anthracene as a bridge, and with the electron-withdrawing property of benzonitrile and the electron-donating property of carbazole or triphenylamine groups, the carrier injection and transport are made more balanced, improving the device performance. The spirofluorene structure can interrupt conjugation, maintain the efficient blue light emission of anthracene, and at the same time can inhibit the close packing between molecules in the aggregated state, obtaining a high fluorescence quantum efficiency, and can also emit efficient blue light in organic solvents. This spirofluorene-based anthracene derivative blue light-emitting material has significant economic value in applications such as preparing light-emitting materials, light-emitting devices, or intelligent materials.

[0057] The present application provides a spirofluorene-based anthracene derivative blue light-emitting material with the following structural formula:

[0058]

[0059] Among them, R is selected from one of the following structural formulas a - q:

[0060]

[0061] In some preferred embodiments, the spirofluorene-based anthracene derivative blue light-emitting material is characterized in that R is selected from the following structural formulas:

[0062] One of them.

[0063] The present application also provides a preparation method of the above-mentioned spirofluorene-based anthracene derivative blue light-emitting material, which is characterized in that S1. 4-cyanophenylboronic acid and 9,10-dibromoanthracene are reacted under the action of the catalyst tetrakis(triphenylphosphine)palladium to obtain 4-(10-bromoanthracen-9-yl)benzonitrile;

[0064] S2. The 4-(10-bromoanthracen-9-yl)benzonitrile prepared in S1 and bis(pinacolato)diboron are reacted under the action of the catalyst bis(triphenylphosphine)palladium dichloride to obtain 4-(10-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)anthracen-9-yl)benzonitrile;

[0065] S3. React 4-bromo-spiro[fluorene-9,8'-[8H]indolo[3,2,1-de]acridine] and 4'-bromo-10-phenyl-10H-spiro[acridine-9,9'-fluorene] respectively with 4-(10-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)anthracen-9-yl)benzonitrile prepared in step S2 under the action of the catalyst tetrakis(triphenylphosphine)palladium to obtain the target products 4-(10-(spiro[fluorenone-9,8'-indolo[3,2,1-de]acridine]-4-yl)anthracen-9-yl)benzonitrile and 4-(10-(10-phenyl-10H-spiro[acridine-9.9-fluorenone]-4'-yl)anthracen-9-yl)benzonitrile.

[0066] In some preferred embodiments, the catalyst for the reaction in step S1 is tetrakis(triphenylphosphine)palladium, and the molar ratio of 9,10-dibromoanthracene, 4-cyanophenylboronic acid, and tetrakis(triphenylphosphine)palladium is (1.0 - 1.5):(1.0 - 1.5):(0.05 - 0.10), the reaction temperature is 90 - 100 °C, and the reaction time is 12 - 24 h.

[0067] In some preferred embodiments, the catalyst for the reaction in step S2 is bis(triphenylphosphine)palladium dichloride, and the molar ratio of 4-(10-bromoanthracen-9-yl)benzonitrile, pinacol diborate, and bis(triphenylphosphine)palladium dichloride is (1.0 - 1.5):(1.5 - 2.0):(0.05 - 0.1), the reaction temperature is 95 - 105 °C, and the reaction time is 12 - 36 h.

[0068] In some preferred embodiments, the catalyst for the reaction in step S3 is tetrakis(triphenylphosphine)palladium, and the molar ratio of 4-bromo-spiro[fluorene-9,8'-[8H]indolo[3,2,1-de]acridine] or 4'-bromo-10-phenyl-10H-spiro[acridine-9,9'-fluorene], 4-(10-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)anthracen-9-yl)benzonitrile, and tetrakis(triphenylphosphine)palladium is (1.0 - 1.5):(1.0 - 1.5):(0.05 - 0.10), the reaction temperature is 90 - 100 °C, and the reaction time is 12 - 24 h.

[0069] This application also provides the use of the above-mentioned spirofluorene-based anthracene derivative blue light-emitting material in the preparation of light-emitting devices or intelligent materials.

[0070] Next, the preparation method of the spirofluorene-based anthracene derivative blue light-emitting material in this application will be introduced in detail.

[0071] Example 1 Preparation of 4-(10-(10-phenyl-10H-spiro[acridine-9.9-fluorenone]-2'-yl)anthracen-9-yl)benzonitrile

[0072] Step 1: Preparation of chalcone (i.e., Compound 1):

[0073] 4-Cyanophenylboronic acid (0.29 g, 2 mmol), 9,10-dibromoanthracene (0.67 g, 2 mmol), and tetrakis(triphenylphosphine)palladium(0) (0.12 g, 0.1 mmol) were successively added to a 250 mL neck flask. The flask was evacuated under vacuum and purged three times with dry nitrogen, and then 40 mL of toluene, 10 mL of absolute ethanol, and 10 mL of saturated K 2 CO 3 aqueous solution were added. The reaction was heated under reflux with stirring at 90 °C for 12 hours. Extraction was carried out using saturated brine and dichloromethane. Distillation under reduced pressure was performed to obtain a pale yellow solid. Using silica gel powder as the stationary phase and petroleum ether / dichloromethane as the eluent, 0.394 g of pale yellow powder was obtained by column chromatography (yield 55%).

[0074] The reaction equation is as follows:

[0075]

[0076] Step 2: Preparation of 4-(10-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)anthracen-9-yl)benzonitrile (i.e., Compound 2):

[0077] 4-(10-Bromoanthracen-9-yl)benzonitrile (0.72 g, 2 mmol), bis(pinacolato)diboron (0.76 g, 3 mmol), potassium acetate (0.4 g, 4 mmol), and bis(triphenylphosphine)palladium(II) dichloride (0.07 g, 0.1 mmol) were successively added to a 100 ml two-neck flask. The flask was evacuated under vacuum and purged three times with dry nitrogen, and then 1,4-dioxane (30 mL) was added. After stirring the reaction at 100 °C for 24 h, extraction was carried out using saturated brine and dichloromethane. Distillation under reduced pressure was performed to obtain a yellow solid. Using silica gel powder as the stationary phase and petroleum ether / dichloromethane as the eluent, 0.58 g of yellow powder was obtained by column chromatography (yield 72%).

[0078] The reaction equation is as follows:

[0079]

[0080] Step 3: Preparation of 4-(10-(spiro[fluorene-9,8'-indolo[3,2,1-de]acridine]-4-yl)anthracen-9-yl)benzonitrile (i.e., the target product STPA-4AnCN)

[0081] 4-(10-(4,4,5,5-Tetramethyl-1,3,2-dioxaborolan-2-yl)anthracen-9-yl)benzonitrile (0.49 g, 1.2 mmol), 4-bromo-spiro[fluorene-9,8'-[8H]indolo[3,2,1-de]acridine] (0.49 g, 1 mmol), and tetrakis(triphenylphosphine)palladium (0.06 g, 0.05 mmol) were successively added to a 100 mL two-necked flask. The flask was evacuated under vacuum and purged three times with dry nitrogen, and then 25 mL of toluene, 5 mL of absolute ethanol, and 5 mL of saturated K 2 CO 3 solution were added. The reaction mixture was heated under reflux with stirring at 95 °C for 16 h. The mixture was extracted with saturated brine and dichloromethane. After distillation under reduced pressure, a yellow solid was obtained. Using silica gel powder as the stationary phase and petroleum ether / ethyl acetate as the eluent, 0.45 g of yellow powder was obtained by column chromatography (yield 65%).

[0082] The reaction equation is as follows:

[0083]

[0084] The NMR spectrum of compound SCZ-4AnCN is as Figure 1 shown. As can be seen from Figure 1 , its characteristic wave numbers (ppm) are 1H NMR (400 MHz, CDCl 3 ) δ 8.35, 8.33, 8.32, 8.30, 8.25, 8.23, 8.02, 8.01, 7.99, 7.98, 7.96, 7.94, 7.85, 7.85, 7.84, 7.83, 7.82, 7.81, 7.80, 7.71, 7.70, 7.69, 7.68, 7.67, 7.65, 7.46, 7.45, 7.44, 7.44, 7.43, 7.42, 7.42, 7.41, 7.40, 7.40, 7.39, 7.39, 7.38, 7.38, 7.37, 7.36, 7.35, 7.34, 7.33, 7.32, 7.32, 7.22, 7.20, 7.18, 7.10, 7.08, 7.00, 6.98, 6.96, 6.94, 6.92, 6.81, 6.81, 6.79, 6.79, 6.70, 6.69, 6.67, 6.65, 6.65, 5.84, 5.82. The peaks can correspond one by one to the hydrogen atoms on the aromatic rings of carbazole, anthracene, and pyridoimidazole, and the quantity is reasonable. It shows that the structure of the 4-(10-(spiro[fluorenone-9,8'-indolo[3,2,1-de]acridine]-4-yl)anthracen-9-yl)benzonitrile compound is single and the purity is high.

[0085] Example 2 Preparation of 4-(10-(10-phenyl-10H-spiro[acridine-9,9'-fluorene]-4'-yl)anthracen-9-yl)benzonitrile

[0086] 4-(10-(4,4,5,5-Tetramethyl-1,3,2-dioxaborolan-2-yl)anthracen-9-yl)benzonitrile prepared in Step 2 of Example 1 can also be used for the preparation of 4-(10-(10-phenyl-10H-spiro[acridine-9,9'-fluorene]-4'-yl)anthracen-9-yl)benzonitrile.

[0087] Step 3: Preparation of 4-(10-(10-phenyl-10H-spiro[acridine-9,9'-fluorene]-4'-yl)anthracen-9-yl)benzonitrile, the target product (STPA-4AnCN)

[0088] Add 4-(10-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)anthracen-9-yl)benzonitrile (0.49 g, 1.2 mmol), 4'-bromo-10-phenyl-10H-spiro[acridine-9,9'-fluorene] (0.49 g, 1 mmol), and tetrakis(triphenylphosphine)palladium (0.06 g, 0.05 mmol) into a 100 mL two-necked flask in sequence. Evacuate the flask under vacuum and displace it three times with dry nitrogen. Then add 25 mL of toluene, 5 mL of absolute ethanol, and 5 mL of saturated K 2 CO 3 solution. Heat and reflux with stirring at 95 °C for 16 hours. Extract with saturated brine and dichloromethane. Distill under reduced pressure to obtain a yellow solid. Use silica gel powder as the stationary phase and petroleum ether / ethyl acetate as the eluent, and obtain 0.43 g of yellow powder (yield 63%) by column chromatography. The reaction equation is as follows:

[0089] The NMR spectrum of compound STPA-4AnCN is as Figure 2 shown. As can be seen from Figure 2 it, its characteristic wave numbers (ppm) are 1H NMR (400 MHz, CDCl 3)δ8.01,8.01,7.99,7.99,7.98,7.97,7.96,7.95,7.84,7.84,7.82,7.82,7.81,7.79,7.77,7.75,7.73,7.70,7.70,7.68,7.68,7.67,7.67,7.66,7.65,7.65,7.64,7.62,7.61,7.59,7.57,7.56,7.55,7.49,7.47,7.45,7.44,7.43,7.42,7.42,7.41,7.40,7.39,7.39,7.38,7.38,7.37,7.37,7.35,7.35,7.32,7.32,7.31,7.30,7.04,7.04,7.02,7.02,7.01,7.01,7.00,7.00,6.99,6.97,6.97,6.72,6.71,6.70,6.68,6.68,6.66,6.64,6.64,6.60,6.60,6.58,6.58,6.43,6.41,5.81,5.79. The peak energy corresponds one by one to the hydrogen atoms on the aromatic rings of carbazole, anthracene, and pyridoimidazole, and the quantity is reasonable. It shows that the structure of the 4-(10-(10-phenyl-10H-spiro[acridine-9,9'-fluorenone]-4'-yl)anthracen-9-yl)benzonitrile compound is single and the purity is high.

[0090] Figure 1 And Figure 2 are the hydrogen spectra of molecules SCZ-4AnCN and STPA-4AnCN measured by a Bruker 400 MHz superconducting nuclear magnetic resonance spectrometer, and the solvent is deuterated chloroform. Figure 3 And Figure 4 are the mass spectra of molecules SCZ-4AnCN and STPA-4AnCN measured by an ultra-high resolution quadrupole combined electrostatic field orbitrap liquid chromatography-mass spectrometry instrument.

[0091] Figure 3 And Figure 4 are the mass spectra of molecules SCZ-4AnCN and STPA-4AnCN measured by a Thermo Fisher ultra-high performance liquid chromatography-tandem triple quadrupole mass spectrometry instrument * / TSQ Endura respectively. The spirofluorene-based anthracene derivative blue light-emitting material was dissolved in dichloromethane to prepare a solution with a concentration of 1 mg / mL for testing. From Figure 3 and Figure 4 it can be seen that the relative molecular masses of SCZ-4AnCN and STPA-4AnCN are 653.24 and 655.26 respectively, which are consistent with the relative molecular masses of the synthesized spirofluorene-based anthracene derivative blue light-emitting materials.

[0092] Characterization and performance testing

[0093] Using the compounds SCZ-4AnCN and STPA-4AnCN prepared in Example 1 and Example 2 as test objects, their photophysical properties were tested, and the test results are as Figures 5 to 7 shown.

[0094] Figure 5 The normalized absorption spectra of the molecules SCZ-4AnCN and STPA-4AnCN in toluene solution measured by a Shimadzu UV-2700 ultraviolet-visible spectrophotometer. The anthracene derivatives were dissolved in toluene to prepare a stock solution of 1×10 -3 mol / L. During the test, it was diluted to 1×10 -5 mol / L. It can be seen from Figure 5 that for the anthracene derivatives, SCZ-4AnCN and STPA-4AnCN both have characteristic absorptions of anthracene at 356 nm, 377 nm, and 397 nm. And the normalized emission spectra of the molecules SCZ-4AnCN and STPA-4AnCN in toluene solution measured by a multi-functional spectrometer. The anthracene derivatives were dissolved in toluene to prepare a stock solution of 1×10 -3 mol / L. During the test, it was diluted to 1×10 -5 mol / L. It can be seen from Figure 5 that for the spirofluorene-based anthracene derivatives SCZ-4AnCN and STPA-4AnCN, the maximum emission wavelengths in toluene solution are both 437 nm, indicating that the spirofluorene-based anthracene derivative blue light-emitting materials all belong to blue light emission in toluene solution.

[0095] Figure 6 The normalized absorption spectra of the molecules SCZ-4AnCN and STPA-4AnCN in toluene solution measured by a Shimadzu UV-2700 ultraviolet-visible spectrophotometer. The spirofluorene-based anthracene derivative blue light-emitting material was dissolved in chlorobenzene solution to a concentration of 5 mg / mL, and 60 μL was taken in a vacuum glove box and coated on a quartz sheet. It can be seen from Figure 6 that for the anthracene derivatives, SCZ-4AnCN and STPA-4AnCN both have characteristic absorptions of anthracene at 350 to 410 nm. And the fluorescence emission spectra of the molecules SCZ-4AnCN and STPA-4AnCN measured by an Edinburgh FLS980 at an excitation wavelength of 365 nm. The spirofluorene-based anthracene derivative blue light-emitting material was dissolved in chlorobenzene solution to a concentration of 5 mg / mL, and 60 μL was taken in a vacuum glove box and coated on a quartz sheet. It can be seen from Figure 7 that the emissions of SCZ-4AnCN and STPA-4AnCN molecules are 440 nm and 439 nm respectively, both belonging to blue light emission.

[0096] Figure 7Redox potentials of molecules SCZ-4AnCN and STPA-4AnCN measured by cyclic voltammetry using a Metrohm PGSTAT 302N high-precision electrochemical workstation. As Figure 7 shown, the oxidation potentials of both are relatively high. For SCZ-4AnCN and STPA-4AnCN, by using ferrocene as an external reference, the HOMO energies are determined to be -5.70 and -5.49 eV respectively, indicating that their highest occupied orbitals are relatively high, which is beneficial to the injection and transport of holes and electrons, and can be used for vacuum evaporation to fabricate organic electroluminescent devices.

[0097] In this application, anthracene with high fluorescence quantum efficiency is used as the parent body. By linking benzonitrile with electron-withdrawing properties and 4-bromo-spiro[fluorene-9,8'-[8H]indolo[3,2,1-de]acridine] and 4'-bromo-10-phenyl-10H-spiro[acridine-9,9'-fluorene] with electron-donating properties, the injection and transport of carriers are made more balanced, thereby improving the performance of the device. The spirofluorene structure can interrupt conjugation, maintain the efficient blue emission of anthracene, and at the same time can inhibit the close packing between molecules in the aggregated state, obtaining a high fluorescence quantum efficiency, and can also emit efficient blue light in organic solvents. As Figure 8 、 Figure 9 shown, the fluorescence quantum yields of SCZ-4AnCN and STPA-4AnCN are 95% and 89% respectively.

[0098] At the same time, the preparation process of the spirofluorene-based anthracene derivative blue light-emitting material of this application is simple, convenient, and can be prepared in large batches, which is conducive to industrial production and the popularization of its application.

[0099] Obviously, the above-mentioned embodiments of this application are merely examples for clearly illustrating this application, and are not intended to limit the implementation manners of this application. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to enumerate all the implementation manners here. Any modifications, equivalent replacements, and improvements made within the spirit and principle of this application shall be included in the protection scope of the claims of this application.

Claims

1. A blue luminescent material based on anthracene derivatives of spirofluorene, characterized in that: It has the following structural formula: Wherein, R is selected from one of the following structural formulas a to q:

2. The anthracene derivative blue light-emitting material based on spirofluorene according to claim 1, characterized in that: R is selected from the following structural formula: One of them.

3. The method for preparing the blue luminescent material based on spirofluorene anthracene derivative according to claim 1 or 2, characterized in that: The following steps are involved: S1. 4-cyanophenylboronic acid and 9,10-dibromoanthracene are reacted in the presence of a catalyst, tetrakistriphenylphosphine palladium, to obtain 4-(10-bromoanthracene-9-yl)benzonitrile; S2. The 4-(10-bromoanthracene-9-yl)benzonitrile prepared in S1 is reacted with diboric acid pinacol ester in the presence of a catalyst, bistriphenylphosphine palladium dichloride, to obtain 4-(10-(4,4,5,5-tetramethyl-1,3,2-dioxaborolane-2-yl)anthracene-9-yl)benzylnitrile; S3. 4-Bromo-spiro[fluorene-9,8'-[8H]indol[3,2,1-DE]acridine] and 4'-bromo-10-phenyl-10H-spiro[acridine-9,9'-fluorene] are reacted with 4-(10-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)anthracen-9-yl)benzonitrile prepared in step S2 under the action of tetrakistriphenylphosphine palladium as a catalyst to obtain the target products 4-(10-(spiro[fluorenone-9,8'-indol[3,2,1-de]acridine]-4-yl)anthracen-9-yl)benzonitrile and 4-(10-(10-phenyl-10H-spiro[acridine-9.9-fluorenone]-4'-yl)anthracen-9-yl)benzonitrile.

4. The method for preparing a blue luminescent material based on anthracene derivatives of spirofluorene according to claim 3, characterized in that: The catalyst for the reaction in step S1 is tetrakistriphenylphosphine palladium, and the molar ratio of 9,10-dibromoanthracene, 4-cyanophenylboric acid, and tetrakistriphenylphosphine palladium is (1.0-1.5):(1.0-1.5):(0.05-0.10), the reaction temperature is 90-100° C., and the reaction time is 12-24 h.

5. The method for preparing the blue luminescent material based on spirofluorene anthracene derivative according to claim 3, characterized in that: The catalyst for the reaction in step S2 is bistriphenylphosphine palladium dichloride, and the molar ratio of 4-(10-bromoanthracene-9-yl)benzonitrile, bipyraclostrobin and bistriphenylphosphine palladium dichloride is (1.0-1.5):(1.5-2.0):(0.05-0.1), the reaction temperature is 95-105° C., and the reaction time is 12-36 h.

6. The method for preparing a blue luminescent material based on anthracene derivatives of spirofluorene according to claim 3, characterized in that: The catalyst for the reaction in step S3 is tetrakistriphenylphosphine palladium, 4-bromo-spiro[fluorene-9,8'-[8H]indole[3,2,1-DE]acridine] or 4'-bromo-10-phenyl-10H-spiro[acridine-9,9'-fluorene], 4-(10-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)anthracene-9-yl)benzonitrile, and the molar ratio of tetrakistriphenylphosphine palladium is (1.0-1.5):(1.0-1.5):(0.05-0.10), the reaction temperature is 90-100°C, and the reaction time is 12-24h.

7. The method for preparing a blue luminescent material based on anthracene derivatives of spirofluorene according to claim 4, characterized in that: The reaction condition in step S1 is heating under reflux under the protection of inert gas.

8. The method for preparing a blue luminescent material based on spirofluorene anthracene derivatives according to claim 5, characterized in that: The solvent for the reaction in step S2 is 1,4-dioxane and the reaction is carried out under an inert gas environment.

9. The method for preparing a blue luminescent material based on anthracene derivatives of spirofluorene according to claim 6, characterized in that: Step S3 also includes post-processing, which includes cooling, extraction, drying, concentration, and separation.

10. Use of the spirofluorene-based anthracene derivative blue light-emitting material according to claims 1 to 2 in the preparation of light-emitting devices or smart materials.

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