Spirobifluorene-based narrow-emission compound and electroluminescent device prepared from spirobifluorene-based narrow-emission compound

Abstract

The invention belongs to the field of organic luminescent materials, and relates to a spirobifluorene-based narrow-emission compound and an electroluminescent device prepared from the spirobifluorene-based narrow-emission compound. The narrow emission compound has one of the following structural general formula: # imgabs0 #. The spirobifluorene-based narrow-emission compound provided by the invention is based on a multiple resonance type TADF material system, spirobifluorene is taken as a parent body, and two conjugated systems separated by a spiro bond can be customized into a bipolar material, so that the voltage of a device can be reduced; the spiro skeleton realizes a relatively rigid face-to-face configuration, and can realize effective space charge transfer and relatively high photoluminescence quantum yield for the TADF luminescent material. The device based on the electroluminescent material realizes the effective improvement of luminous efficiency and brightness, takes into account the advantage of narrow-band emission, and adapts to the development demand of the market on the high-definition display technology.

Description

Technical Field

[0001] The invention belongs to the field of organic luminescent materials and relates to a narrow emission compound based on spirobifluorene and an electroluminescent device prepared therefrom. Background Art

[0002] Organic light-emitting diodes (OLEDs) are gradually becoming an indispensable technology in the field of next-generation display and lighting technologies. Their advantages are that they are almost unlimited in shape, can be easily deposited on flexible substrates, and can even be transparent and emit light from both sides. These characteristics greatly enrich the design possibilities of future electronic devices and improve the user experience.

[0003] The development of OLEDs is closely linked to the research of organic materials, especially those conjugated units that can efficiently transport charges and effectively generate light. At present, technicians in this field have explored various types of organic compounds, including but not limited to aromatic hydrocarbons, heterocycles, metal complexes, aromatic amines, and aromatic boranes, which are widely used in different generations of OLEDs. These OLEDs can be roughly divided into three generations according to the different light-emitting principles: the first generation is based on fluorescent materials, the second generation uses phosphorescent materials, and the third generation relies on thermally activated delayed fluorescence (TADF) as the light-emitting pathway.

[0004] In the study of TADF materials, the traditional method is to design molecules with a donor-acceptor [DA] type structure, which promotes the intersystem crossover process from singlet to triplet through the twisted conformation inside the molecule, thereby improving the luminescence efficiency. However, this twisted molecular configuration often leads to a decrease in the fluorescence quantum yield, affecting the overall performance of the material.

[0005] In response to this challenge, it is particularly urgent to develop new OLED materials and device structures. The ideal new material should be able to maintain efficient luminescence while overcoming the problem of decreased fluorescence quantum yield caused by the distortion of the molecular configuration of traditional TADF materials, so as to improve the stability and brightness of the material without sacrificing luminescence efficiency. Summary of the invention

[0006] The present invention aims at the above problems existing in the prior art and provides a boron-nitrogen narrow emission compound based on spirobifluorene and an electroluminescent device prepared therefrom.

[0007] One object of the present invention is achieved by the following technical solutions:

[0008] A narrow emission compound based on spirobifluorene, wherein the narrow emission compound has one of the following general structural formulas: ;

[0009] Among them, R and R' are independently selected from one or more of hydrogen atoms, fluorine atoms, chlorine atoms, bromine atoms, cyano groups, alkyl groups, aromatic rings composed of carbon and hydrogen atoms, aromatic heterocycles composed of carbon, nitrogen and hydrogen atoms, aromatic heterocycles composed of carbon, nitrogen, oxygen and hydrogen atoms, aromatic heterocycles composed of carbon, sulfur and hydrogen atoms, and aromatic heterocycles composed of carbon, nitrogen, sulfur and hydrogen atoms.

[0010] Preferably, R and R' are independently selected from one or more of hydrogen atoms, fluorine atoms, chlorine atoms, bromine atoms, cyano groups, C1-C10 straight-chain alkyl groups, C1-C10 branched-chain alkyl groups, C3-C10 aromatic rings composed of carbon and hydrogen atoms, C3-C10 aromatic heterocycles composed of carbon, nitrogen and hydrogen atoms, C3-C10 aromatic heterocycles composed of carbon, nitrogen, oxygen and hydrogen atoms, C3-C10 aromatic heterocycles composed of carbon, sulfur and hydrogen atoms, and C3-C10 aromatic heterocycles composed of carbon, nitrogen, sulfur and hydrogen atoms.

[0011] Preferably, R and R' are independently selected from one of the following group structures I to XXV: .

[0012] The R and R' may be the same or different groups.

[0013] Preferably, the spirobifluorene-based narrow emission compound has a structural formula of one of the following (1) to (100): .

[0014] The second object of the present invention is achieved by the following technical solutions:

[0015] A method for preparing a narrow emission compound based on spirobifluorene, the method comprising the following steps: mixing spirobifluorene, an amine compound, a catalyst, an electron-rich ligand, a base and an organic solvent for a first reaction to obtain an intermediate 1; mixing the intermediate 1, 3-bromo-5-methyl-N,N-diphenylaniline, a catalyst, an electron-rich ligand, a base and an organic solvent for a second reaction to obtain an intermediate 2; and mixing the intermediate 2, a boron halide and an organic solvent for a third reaction to obtain the narrow emission compound based on spirobifluorene.

[0016] The spirobifluorene-based narrow emission compound of the present invention uses spirobifluorene as a matrix, obtains its core skeleton intermediate through a series of Hartwig-Buchwald reactions, and is finally synthesized through a one-pot method.

[0017] Preferably, the spirobifluorene in the first reaction includes one or more of 2,2'-dibromo-9,9'-spirobifluorene, 2,7-dibromo-9,9'-spirobifluorene, 3,6-dibromo-9,9'-spirobifluorene, and 3,3'-dibromo-9,9'-spirobifluorene.

[0018] Preferably, the amine compound in the first reaction includes one or more of 2,6-difluoroaniline, o-cyanoaniline, p-cyanoaniline, 2-aminoisophthalonitrile, 3-aminoophthalonitrile, 4-aminoisophthalonitrile, 5-aminoisophthalonitrile, 2-fluoroaniline, 3-fluoroaniline, 4-fluoroaniline, methylamine, 2,4-difluoroaniline, 3,5-difluoroaniline, o-chloroaniline, 3-chloroaniline, 4-chloroaniline, 2,6-dichloroaniline, 2,3-dichloroaniline, 2,4-dichloroaniline, 3,5-dichloroaniline, (4-chloro-2-methylphenyl)(methyl)sulfane, 3-chloro-2-methylsulfinylaniline, 3-aminobiphenyl, and [1,1':3',1''-terphenyl]-5'-amine.

[0019] Preferably, the catalyst in the first reaction and / or the second reaction is a palladium catalyst, including one or more of Pd2(dba)3, Pd(OAc)2, PdCl2(dppf), Pd(dba)2, and Pd(PPh3)4. More preferably, Pd2(dba)3.

[0020] The catalysts in the first reaction and the second reaction may be the same or different.

[0021] Preferably, the electron-rich ligand in the first reaction and / or the second reaction comprises one or more of tBu3PHBF4, Xantphos, BINAP, P(t-Bu)3, dtbpf, and RuPhos. More preferably, one or two of tBu3PHBF4 and Xantphos.

[0022] The electron-rich ligands in the first reaction and the second reaction may be the same or different.

[0023] Preferably, the base in the first reaction and / or the second reaction comprises one or more of tBuONa, Cs2CO3, tBuOK, DBU, DABCO, Et3N, DIPEA, K2CO3, Na2CO3, K3PO4, NaOH, and KOH.

[0024] The bases in the first reaction and the second reaction may be the same or different.

[0025] Preferably, the organic solvent in the first reaction and / or the second reaction and / or the third reaction includes one or more of toluene, dichlorobenzene, xylene, n-hexane, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, tetrahydrofuran, isopropanol, benzonitrile, dichloromethane and ethyl acetate.

[0026] The organic solvents in the first reaction, the second reaction and the third reaction may be the same or different.

[0027] Preferably, the boron halide in the third reaction includes one or more of boron bromide, boron chloride, and boron iodide, and more preferably boron bromide.

[0028] Preferably, the ratio of spirobifluorene, amine compound, catalyst, electron-rich ligand, base and solvent in the first reaction is (5-15) mmol: (15-30) mmol: (0.1-0.5) mol: (0.1-1.0) mol: (10-50) mmol: (10-100) mL.

[0029] Preferably, the ratio of the intermediate 1, 3-bromo-5-methyl-N,N-diphenylaniline, catalyst, electron-rich ligand, base and solvent in the second reaction is (1-10) mmol: (10-20) mmol: (0.1-0.5) mol: (0.1-1.0) mol: (10-50) mmol: (10-100) mL.

[0030] Preferably, in the third reaction, the ratio of intermediate 2, boron halide and solvent is (0.1-5) mmol: (10-20) mmol: (10-30) ml.

[0031] Preferably, the reaction temperature of the first reaction is 100-150° C., and the reaction time is 10-30 h.

[0032] Preferably, the reaction temperature of the second reaction is 100-150° C., and the reaction time is 10-30 h.

[0033] Preferably, the reaction temperature of the third reaction is 180-220° C., and the reaction time is 30-50 h.

[0034] Preferably, after the first reaction and the second reaction are completed, the reaction products are filtered and washed to remove the organic solvent, and purified by column chromatography.

[0035] Preferably, the third reaction is carried out in a sealed environment and / or under inert gas protection. After the third reaction is completed, ethanol is added to the reaction product at -20 to 0°C to terminate the reaction, the organic solvent is removed by vacuum concentration, and the product is purified by column chromatography.

[0036] The third object of the present invention is achieved by the following technical solutions:

[0037] An electroluminescent device comprises an organic functional layer unit in its structure, and the organic functional layer unit comprises the above-mentioned narrow emission compound based on spirobifluorene.

[0038] Preferably, the electroluminescent device comprises the following structure: an ITO substrate, and an anode layer, an organic functional layer unit and a cathode layer sequentially formed on the ITO substrate.

[0039] Preferably, the organic functional layer unit comprises a hole injection layer, a hole transport layer, a light-emitting layer and an electron transport layer; the light-emitting layer comprises one or more narrow emission compounds based on spirobifluorene.

[0040] Preferably, the electroluminescent device includes one or more of a full-color display, a photovoltaic device, a light-emitting display device, and an organic light-emitting diode.

[0041] The fourth object of the present invention is achieved by the following technical solutions:

[0042] A method for preparing an electroluminescent device comprises the following steps: forming an anode layer, an organic functional layer unit and a cathode layer on an ITO substrate in sequence by adopting a thermal evaporation and / or spin coating method.

[0043] Compared with the prior art, the present invention has the following beneficial effects:

[0044] 1. The present invention provides a narrow emission compound based on spirobifluorene, based on a multi-resonance TADF (MR-TADF) material system. This system uses spirobifluorene as the matrix and cleverly combines electron-deficient B elements and electron-rich fifth and sixth main group elements. The two conjugated systems separated by the spirocyclic bond can be customized as bipolar materials, which can reduce the device voltage; the spirocyclic skeleton realizes a relatively rigid face-to-face configuration, overcomes the shortcomings of traditional TADF materials, and realizes effective spatial charge transfer and high photoluminescence quantum yield (PLQY) for TADF luminescent materials. In addition, MR-TADF materials can produce an emission spectrum with a narrow half-peak width, which can provide light with higher color purity, which is crucial to improving display quality and color expression.

[0045] 2. The present invention provides a narrow emission compound based on spirobifluorene, which significantly enhances the electron transport ability of the material while maintaining its narrow-band luminescence characteristics by introducing functional groups on the spirobifluorene core. This improvement is particularly important for the preparation of efficient narrow-band blue light OLED devices, and can significantly improve the overall performance of the device. Specifically, the present invention effectively hinders the expansion of the conjugated structure within the molecule by simultaneously introducing symmetrical functional groups on both sides of the spirobifluorene molecule, resulting in a deep blue light emission wavelength. In addition, the compound also greatly improves the luminous efficiency of the material through a multi-channel radiation attenuation process and an effective energy transfer mechanism. These characteristics work together to enable the compound to show excellent potential in the preparation of high-performance narrow-band OLED devices, which can significantly improve the working efficiency and service life of the device.

[0046] 3. The narrow emission compound based on spirobifluorene provided by the present invention has excellent thermal stability. Through the optimized molecular structure, the stability and reliability of the material under high temperature conditions are ensured, which is crucial to prolonging the service life of the device; through the fine control of the molecular design, the effective control of the luminescence spectrum width is achieved, the characteristics of narrow-band emission are ensured, and it is helpful to obtain a light source with high color purity; by optimizing the transmission balance of electrons and holes, the external quantum efficiency of the electroluminescent device is significantly improved, thereby increasing the luminous intensity while reducing energy consumption. In addition, the electroluminescent device prepared using the compound can significantly improve the external quantum efficiency under the premise of effectively controlling the full width at half maximum (FWHM).

[0047] 4. The present invention provides a narrow emission compound based on spirobifluorene, which can significantly improve the physical and chemical properties of the material by changing the modification group on the aromatic structure, thereby showing better performance in organic semiconductor devices. The present invention not only optimizes the basic physical and chemical properties of the material, but also shows better comprehensive performance in organic semiconductor devices, providing new material selection and technical support for the development of high-performance OLED devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 These are the absorption and emission spectra of the compounds of Examples 1, 26, 51 and 76 of the present invention in toluene solution.

[0049] Figure 2 The thermogravimetric analysis and differential scanning calorimetry curves of the compounds of Examples 1, 26, 51 and 76 of the present invention are shown.

[0050] Figure 3 It is the current density-voltage-brightness curve of the organic electroluminescent device prepared by the compounds of Examples 1, 26, 51 and 76 of the present invention.

[0051] Figure 4The external quantum efficiency-brightness curve and luminescence spectrum of the organic electroluminescent device prepared from the compounds of Examples 1, 26, 51 and 76 of the present invention. DETAILED DESCRIPTION

[0052] The technical solution of the present invention is further described below in conjunction with specific embodiments. It should be understood that the specific embodiments described herein are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the claims attached to this application.

[0053] Example 1

[0054] The narrow emission compound based on spirobifluorene in this embodiment has the structural formula (1) above, and its synthesis route is as follows:

[0055] ;

[0056] The preparation method of the above compound comprises the following steps:

[0057] (1) In a 100 mL flask filled with argon, a mixture of 2,2'-dibromo-9,9'-spirobifluorene (4.74 g, 10.0 mmol), 2,6-difluoroaniline (2.84 g, 22.0 mmol), Pd2(dba)3 (0.18 g, 0.2 mol), tBu3PHBF4 (0.15 g, 0.5 mol), tBuONa (2.88 g, 30.0 mmol) and 50 mL of toluene was stirred at 110°C overnight; the cooled mixture was filtered through celite and washed with dichloromethane to remove the organic solvent; the solid was further purified by silica gel flash column chromatography (eluted with petroleum ether / dichloromethane) to obtain intermediate 1 as a white solid (5.13 g, 9.0 mmol, yield 90%);

[0058] (2) In a 100 mL flask filled with argon, a mixture of intermediate 1 (2.85 g, 5.0 mmol), 3-bromo-5-methyl-N,N-diphenylaniline (5.07 g, 15.0 mmol), Pd2(dba)3 (0.14 g, 0.15 mol), Xantphos (0.12 g, 0.25 mol), tBuONa (1.44 g, 15.0 mmol) and 50 mL of toluene was vigorously stirred at 120 °C overnight; after cooling to room temperature, the mixture was filtered through celite and washed with dichloromethane to remove the organic solvent; the solid was further purified by silica gel flash column chromatography (eluted with petroleum ether / dichloromethane) to obtain intermediate 2 as a white solid (4.34 g, 4.0 mmol, yield 80%);

[0059] (3) In a 120 mL sealed tube under argon protection, intermediate 2 (1.09 g, 1.0 mmol) and 15 mL of dichlorobenzene (o-DCB) were added; boron bromide (3.00 g, 12.0 mmol) was added and the sealed tube was sealed, and the reaction was stirred at 200 °C for 36 h; after cooling to room temperature, ethanol (5.0 mL) was slowly added in an ice bath to terminate the reaction; the organic solvent was concentrated in vacuo, and the remaining solid was purified by silica gel flash column chromatography (eluted with petroleum ether / dichloromethane) to obtain compound 1 as a bright yellow solid (0.83 g, 0.75 mmol, yield 75%).

[0060] Example 2

[0061] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (2) above.

[0062] The difference between this example and Example 1 is that the 2,6-difluoroaniline in step (1) of the preparation method is replaced by an equivalent amount of o-cyanoaniline, and the other raw materials and steps are the same as Example 1, and finally Compound 2 is obtained (yield 75%).

[0063] Example 3

[0064] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (3) above.

[0065] The difference between this example and Example 1 is that the 2,6-difluoroaniline in step (1) of the preparation method is replaced by an equivalent amount of p-cyanoaniline, and the other raw materials and steps are the same as Example 1, and finally compound 3 is obtained (yield 70%).

[0066] Example 4

[0067] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (4) above.

[0068] The difference between this example and Example 1 is that the 2,6-difluoroaniline in step (1) of the preparation method is replaced by an equivalent amount of 2-aminoisophthalonitrile, and the other raw materials and steps are the same as Example 1, and finally compound 4 is obtained (yield 76%).

[0069] Example 5

[0070] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (5) above.

[0071] The difference between this example and Example 1 is that the 2,6-difluoroaniline in step (1) of the preparation method is replaced by an equivalent amount of 3-aminophthalonitrile, and the other raw materials and steps are the same as Example 1, and finally compound 5 is obtained (yield 74%).

[0072] Example 6

[0073] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (6) above.

[0074] The difference between this example and Example 1 is that the 2,6-difluoroaniline in step (1) of the preparation method is replaced by an equivalent amount of 4-aminoisophthalonitrile, and the other raw materials and steps are the same as Example 1, and finally compound 6 is obtained (yield 71%).

[0075] Example 7

[0076] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (7) above.

[0077] The difference between this example and Example 1 is that the 2,6-difluoroaniline in step (1) of the preparation method is replaced by an equivalent amount of 5-aminoisophthalonitrile, and the other raw materials and steps are the same as Example 1, and finally compound 7 is obtained (yield 72%).

[0078] Example 8

[0079] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (8) above.

[0080] The difference between this example and Example 1 is that the 2,6-difluoroaniline in step (1) of the preparation method is replaced by an equivalent amount of 2-fluoroaniline, and the other raw materials and steps are the same as Example 1, and finally compound 8 is obtained (yield 70%).

[0081] Example 9

[0082] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (9) above.

[0083] The difference between this example and Example 1 is that the 2,6-difluoroaniline in step (1) of the preparation method is replaced by an equivalent amount of 3-fluoroaniline, and the other raw materials and steps are the same as Example 1, and finally compound 9 is obtained (yield 72%).

[0084] Example 10

[0085] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (10) above.

[0086] The difference between this example and Example 1 is that the 2,6-difluoroaniline in step (1) of the preparation method is replaced by an equivalent amount of 4-fluoroaniline, and the other raw materials and steps are the same as Example 1, and finally compound 10 is obtained (yield 78%).

[0087] Embodiment 11

[0088] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (11) above.

[0089] The difference between this example and Example 1 is that the 2,6-difluoroaniline in step (1) of the preparation method is replaced by an equivalent amount of methylamine, and the other raw materials and steps are the same as Example 1, and finally compound 11 is obtained (yield 76%).

[0090] Example 12

[0091] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (12) above.

[0092] The difference between this example and Example 1 is that the 2,6-difluoroaniline in step (1) of the preparation method is replaced by an equivalent amount of 2,3-difluoroaniline, and the other raw materials and steps are the same as Example 1, and finally compound 12 is obtained (yield 71%).

[0093] Example 13

[0094] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (13) above.

[0095] The difference between this example and Example 1 is that the 2,6-difluoroaniline in step (1) of the preparation method is replaced by an equivalent amount of 2,4-difluoroaniline, and the other raw materials and steps are the same as Example 1, and finally compound 13 is obtained (yield 78%).

[0096] Embodiment 14

[0097] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (14) above.

[0098] The difference between this example and Example 1 is that the 2,6-difluoroaniline in step (1) of the preparation method is replaced by an equivalent amount of 3,5-difluoroaniline, and the other raw materials and steps are the same as Example 1, and finally compound 14 is obtained (yield 72%).

[0099] Embodiment 15

[0100] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (15) above.

[0101] The difference between this example and Example 1 is that the 2,6-difluoroaniline in step (1) of the preparation method is replaced by an equivalent amount of o-chloroaniline, and the other raw materials and steps are the same as Example 1, and finally compound 15 is obtained (yield 77%).

[0102] Example 16

[0103] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (16) above.

[0104] The difference between this example and Example 1 is that the 2,6-difluoroaniline in step (1) of the preparation method is replaced by an equivalent amount of 3-chloroaniline, and the other raw materials and steps are the same as Example 1, and finally compound 16 is obtained (yield 70%).

[0105] Embodiment 17

[0106] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (17) above.

[0107] The difference between this example and Example 1 is that the 2,6-difluoroaniline in step (1) of the preparation method is replaced by an equivalent amount of 4-chloroaniline, and the other raw materials and steps are the same as Example 1, and finally compound 17 is obtained (yield 77%).

[0108] Embodiment 18

[0109] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (18) above.

[0110] The difference between this example and Example 1 is that the 2,6-difluoroaniline in step (1) of the preparation method is replaced by an equivalent amount of 2,6-dichloroaniline, and the other raw materials and steps are the same as Example 1, and finally compound 18 is obtained (yield 71%).

[0111] Embodiment 19

[0112] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (19) above.

[0113] The difference between this example and Example 1 is that the 2,6-difluoroaniline in step (1) of the preparation method is replaced by an equivalent amount of 2,3-dichloroaniline, and the other raw materials and steps are the same as Example 1, and finally compound 19 is obtained (yield 74%).

[0114] Embodiment 20

[0115] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (20) above.

[0116] The difference between this example and Example 1 is that the 2,6-difluoroaniline in step (1) of the preparation method is replaced by an equivalent amount of 2,4-dichloroaniline, and the other raw materials and steps are the same as Example 1, and finally compound 20 is obtained (yield 72%).

[0117] Embodiment 21

[0118] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (21) above.

[0119] The difference between this example and Example 1 is that the 2,6-difluoroaniline in step (1) of the preparation method is replaced by an equivalent amount of 3,5-dichloroaniline, and the other raw materials and steps are the same as Example 1, and finally compound 21 is obtained (yield 76%).

[0120] Embodiment 22

[0121] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (22) above.

[0122] The difference between this example and Example 1 is that the 2,6-difluoroaniline in step (1) of the preparation method is replaced by an equivalent amount of (4-chloro-2-methylphenyl)(methyl)sulfane, and the other raw materials and steps are the same as those in Example 1, and finally compound 22 is obtained (yield 73%).

[0123] Embodiment 23

[0124] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (23) above.

[0125] The difference between this example and Example 1 is that the 2,6-difluoroaniline in step (1) of the preparation method is replaced by an equivalent amount of 3-chloro-2-methanesulfinylaniline, and the other raw materials and steps are the same as Example 1, and finally compound 23 is obtained (yield 69%).

[0126] Embodiment 24

[0127] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (24) above.

[0128] The difference between this example and Example 1 is that the 2,6-difluoroaniline in step (1) of the preparation method is replaced by an equivalent amount of 3-aminobiphenyl, and the other raw materials and steps are the same as Example 1, and finally compound 24 is obtained (yield 78%).

[0129] Embodiment 25

[0130] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (25) above.

[0131] The difference between this example and Example 1 is that the 2,6-difluoroaniline in step (1) of the preparation method is replaced by an equivalent amount of [1,1':3',1''-terphenyl]-5'-amine, and the other raw materials and steps are the same as Example 26, and finally Compound 25 is obtained (yield 71%).

[0132] Embodiment 26

[0133] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (26) above.

[0134] The preparation method of the above compound comprises the following steps:

[0135] (1) In a 100 mL flask filled with argon, a mixture of 2,7-dibromo-9,9'-spirobifluorene (4.74 g, 10.0 mmol), 2,6-difluoroaniline (2.84 g, 22.0 mmol), Pd2(dba)3 (0.18 g, 0.2 mol), tBu3PHBF4 (0.15 g, 0.5 mol), tBuONa (2.88 g, 30.0 mmol) and 50 mL of toluene was stirred at 110 °C overnight; the cooled mixture was filtered through celite and washed with dichloromethane to remove the organic solvent; the solid was further purified by silica gel flash column chromatography (eluted with petroleum ether / dichloromethane) to obtain intermediate 1 as a white solid (5.11 g, 9.0 mmol, yield 90%);

[0136] (2) to (3) were the same as (2) to (3) in Example 1, and compound 26 was finally obtained (yield 72%).

[0137] Embodiment 27

[0138] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (27) above.

[0139] The difference between this example and Example 26 is that the 2,6-difluoroaniline in step (1) of the preparation method is replaced by an equivalent amount of o-cyanoaniline, and the other raw materials and steps are the same as Example 26, and finally Compound 27 is obtained (yield 75%).

[0140] Embodiment 28

[0141] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (28) above.

[0142] The difference between this example and Example 26 is that the 2,6-difluoroaniline in step (1) of the preparation method is replaced by an equivalent amount of p-cyanoaniline, and the other raw materials and steps are the same as Example 26, and finally Compound 28 is obtained (yield 78%).

[0143] Embodiment 29

[0144] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (29) above.

[0145] The difference between this example and Example 26 is that the 2,6-difluoroaniline in step (1) of the preparation method is replaced by an equivalent amount of 2-aminoisophthalonitrile, and the other raw materials and steps are the same as Example 26, and finally Compound 29 is obtained (yield 71%).

[0146] Embodiment 30

[0147] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (30) above.

[0148] The difference between this example and Example 26 is that the 2,6-difluoroaniline in step (1) of the preparation method is replaced by an equivalent amount of 3-aminophthalonitrile, and the other raw materials and steps are the same as Example 26, and finally Compound 30 is obtained (yield 76%).

[0149] Embodiment 31

[0150] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (31) above.

[0151] The difference between this example and Example 26 is that the 2,6-difluoroaniline in step (1) of the preparation method is replaced by an equivalent amount of 4-aminoisophthalonitrile, and the other raw materials and steps are the same as Example 26, and finally compound 31 is obtained (yield 71%).

[0152] Embodiment 32

[0153] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (32) above.

[0154] The difference between this example and Example 26 is that the 2,6-difluoroaniline in step (1) of the preparation method is replaced by an equivalent amount of 5-aminoisophthalonitrile, and the other raw materials and steps are the same as Example 26, and finally compound 32 is obtained (yield 73%).

[0155] Embodiment 33

[0156] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (33) above.

[0157] The difference between this example and Example 26 is that the 2,6-difluoroaniline in step (1) of the preparation method is replaced by an equivalent amount of 2-fluoroaniline, and the other raw materials and steps are the same as Example 26, and finally compound 33 is obtained (yield 74%).

[0158] Embodiment 34

[0159] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (34) above.

[0160] The difference between this example and Example 26 is that the 2,6-difluoroaniline in step (1) of the preparation method is replaced by an equivalent amount of 3-fluoroaniline, and the other raw materials and steps are the same as Example 26, and finally compound 34 is obtained (yield 80%).

[0161] Embodiment 35

[0162] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (35) above.

[0163] The difference between this example and Example 26 is that the 2,6-difluoroaniline in step (1) of the preparation method is replaced by an equivalent amount of 4-fluoroaniline, and the other raw materials and steps are the same as Example 26, and finally compound 35 is obtained (yield 83%).

[0164] Embodiment 36

[0165] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (36) above.

[0166] The difference between this example and Example 26 is that the 2,6-difluoroaniline in step (1) of the preparation method is replaced by an equivalent amount of methylamine, and the other raw materials and steps are the same as Example 26, and finally compound 36 is obtained (yield 71%).

[0167] Embodiment 37

[0168] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (37) above.

[0169] The difference between this example and Example 26 is that the 2,6-difluoroaniline in step (1) of the preparation method is replaced by an equivalent amount of 2,3-difluoroaniline, and the other raw materials and steps are the same as Example 26, and finally compound 37 is obtained (yield 76%).

[0170] Embodiment 38

[0171] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (38) above.

[0172] The difference between this example and Example 26 is that the 2,6-difluoroaniline in step (1) of the preparation method is replaced by an equivalent amount of 2,4-difluoroaniline, and the other raw materials and steps are the same as Example 26, and finally compound 38 is obtained (yield 73%).

[0173] Embodiment 39

[0174] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (39) above.

[0175] The difference between this example and Example 26 is that the 2,6-difluoroaniline in step (1) of the preparation method is replaced by an equivalent amount of 3,5-difluoroaniline, and the other raw materials and steps are the same as Example 26, and finally compound 39 is obtained (yield 75%).

[0176] Embodiment 40

[0177] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (40) above.

[0178] The difference between this example and Example 26 is that the 2,6-difluoroaniline in step (1) of the preparation method is replaced by an equivalent amount of o-chloroaniline, and the other raw materials and steps are the same as Example 26, and finally compound 40 is obtained (yield 79%).

[0179] Embodiment 41

[0180] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (41) above.

[0181] The difference between this example and Example 26 is that the 2,6-difluoroaniline in step (1) of the preparation method is replaced by an equivalent amount of 3-chloroaniline, and the other raw materials and steps are the same as Example 26, and finally compound 41 is obtained (yield 74%).

[0182] Embodiment 42

[0183] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (42) above.

[0184] The difference between this example and Example 26 is that the 2,6-difluoroaniline in step (1) of the preparation method is replaced by an equivalent amount of 4-chloroaniline, and the other raw materials and steps are the same as Example 26, and finally compound 42 is obtained (yield 77%).

[0185] Embodiment 43

[0186] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (43) above.

[0187] The difference between this example and Example 26 is that the 2,6-difluoroaniline in step (1) of the preparation method is replaced by an equivalent amount of 2,6-dichloroaniline, and the other raw materials and steps are the same as Example 26, and finally compound 43 is obtained (yield 76%).

[0188] Embodiment 44

[0189] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (44) above.

[0190] The difference between this example and Example 26 is that the 2,6-difluoroaniline in step (1) of the preparation method is replaced by an equivalent amount of 2,3-dichloroaniline, and the other raw materials and steps are the same as Example 26, and finally compound 44 is obtained (yield 79%).

[0191] Embodiment 45

[0192] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (45) above.

[0193] The difference between this example and Example 26 is that the 2,6-difluoroaniline in step (1) of the preparation method is replaced by an equivalent amount of 2,4-dichloroaniline, and the other raw materials and steps are the same as Example 26, and finally compound 45 is obtained (yield 86%).

[0194] Embodiment 46

[0195] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (46) above.

[0196] The difference between this example and Example 26 is that the 2,6-difluoroaniline in step (1) of the preparation method is replaced by an equivalent amount of 3,5-dichloroaniline, and the other raw materials and steps are the same as Example 26, and finally compound 46 is obtained (yield 70%).

[0197] Embodiment 47

[0198] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (47) above.

[0199] The difference between this example and Example 26 is that the 2,6-difluoroaniline in step (1) of the preparation method is replaced by an equivalent amount of (4-chloro-2-methylphenyl)(methyl)sulfane, and the other raw materials and steps are the same as Example 26, and finally Compound 47 is obtained (yield 76%).

[0200] Embodiment 48

[0201] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (48) above.

[0202] The difference between this example and Example 26 is that the 2,6-difluoroaniline in step (1) of the preparation method is replaced by an equivalent amount of 3-chloro-2-methanesulfinylaniline, and the other raw materials and steps are the same as Example 26, and finally Compound 48 is obtained (yield 79%).

[0203] Embodiment 49

[0204] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (49) above.

[0205] The difference between this example and Example 26 is that the 2,6-difluoroaniline in step (1) of the preparation method is replaced by an equivalent amount of 3-aminobiphenyl, and the other raw materials and steps are the same as Example 26, and finally compound 49 is obtained (yield 76%).

[0206] Embodiment 50

[0207] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (50) above.

[0208] The difference between this example and Example 26 is that the 2,6-difluoroaniline in step (1) of the preparation method is replaced by an equivalent amount of [1,1':3',1''-terphenyl]-5'-amine, and the other raw materials and steps are the same as Example 26, and finally Compound 50 is obtained (yield 80%).

[0209] Embodiment 51

[0210] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (51) above.

[0211] The preparation method of the above compound comprises the following steps:

[0212] (1) In a 100 mL flask filled with argon, a mixture of 3,6-dibromo-9,9'-spirobifluorene (4.74 g, 10.0 mmol), 2,6-difluoroaniline (2.84 g, 22.0 mmol), Pd2(dba)3 (0.18 g, 0.2 mol), tBu3PHBF4 (0.15 g, 0.5 mol), tBuONa (2.88 g, 30.0 mmol) and 50 mL of toluene was stirred at 110 °C overnight; the cooled mixture was filtered through celite and washed with dichloromethane to remove the organic solvent; the solid was further purified by silica gel flash column chromatography (eluted with petroleum ether / dichloromethane) to obtain intermediate 1 as a white solid (5.15 g, 9.0 mmol, yield 90%);

[0213] (2) to (3) were the same as (2) to (3) in Example 1, and compound 51 was finally obtained (yield 76%).

[0214] Embodiment 52

[0215] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (52) above.

[0216] The difference between this example and Example 51 is that the 2,6-difluoroaniline in step (1) of the preparation method is replaced by an equivalent amount of o-cyanoaniline, and the other raw materials and steps are the same as Example 51, and finally Compound 52 is obtained (yield 76%).

[0217] Embodiment 53

[0218] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (53) above.

[0219] The difference between this example and Example 51 is that the 2,6-difluoroaniline in step (1) of the preparation method is replaced by an equivalent amount of p-cyanoaniline, and the other raw materials and steps are the same as Example 51, and finally Compound 53 is obtained (yield 79%).

[0220] Embodiment 54

[0221] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (54) above.

[0222] The difference between this example and Example 51 is that the 2,6-difluoroaniline in step (1) of the preparation method is replaced by an equivalent amount of 2-aminoisophthalonitrile, and the other raw materials and steps are the same as Example 51, and finally Compound 54 is obtained (yield 73%).

[0223] Embodiment 55

[0224] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (55) above.

[0225] The difference between this example and Example 51 is that the 2,6-difluoroaniline in step (1) of the preparation method is replaced by an equivalent amount of 3-aminophthalonitrile, and the other raw materials and steps are the same as Example 51, and finally Compound 55 is obtained (yield 80%).

[0226] Embodiment 56

[0227] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (56) above.

[0228] The difference between this example and Example 51 is that the 2,6-difluoroaniline in step (1) of the preparation method is replaced by an equivalent amount of 4-aminoisophthalonitrile, and the other raw materials and steps are the same as Example 51, and finally Compound 56 is obtained (yield 79%).

[0229] Embodiment 57

[0230] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (57) above.

[0231] The difference between this example and Example 51 is that the 2,6-difluoroaniline in step (1) of the preparation method is replaced by an equivalent amount of 5-aminoisophthalonitrile, and the other raw materials and steps are the same as Example 51, and finally Compound 57 is obtained (yield 76%).

[0232] Embodiment 58

[0233] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (58) above.

[0234] The difference between this example and Example 51 is that the 2,6-difluoroaniline in step (1) of the preparation method is replaced by an equivalent amount of 2-fluoroaniline, and the other raw materials and steps are the same as Example 51, and finally Compound 58 is obtained (yield 76%).

[0235] Embodiment 59

[0236] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (59) above.

[0237] The difference between this example and Example 51 is that the 2,6-difluoroaniline in step (1) of the preparation method is replaced by an equivalent amount of 3-fluoroaniline, and the other raw materials and steps are the same as Example 51, and finally Compound 59 is obtained (yield 76%).

[0238] Embodiment 60

[0239] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (60) above.

[0240] The difference between this example and Example 51 is that the 2,6-difluoroaniline in step (1) of the preparation method is replaced by an equivalent amount of 4-fluoroaniline, and the other raw materials and steps are the same as Example 51, and finally compound 60 is obtained (yield 86%).

[0241] Embodiment 61

[0242] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (61) above.

[0243] The difference between this example and Example 51 is that the 2,6-difluoroaniline in step (1) of the preparation method is replaced by an equivalent amount of methylamine, and the other raw materials and steps are the same as Example 51, and finally Compound 61 is obtained (yield 73%).

[0244] Embodiment 62

[0245] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (62) above.

[0246] The difference between this example and Example 51 is that the 2,6-difluoroaniline in step (1) of the preparation method is replaced by an equivalent amount of 2,3-difluoroaniline, and the other raw materials and steps are the same as Example 51, and finally compound 62 is obtained (yield 73%).

[0247] Embodiment 63

[0248] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (63) above.

[0249] The difference between this example and Example 51 is that the 2,6-difluoroaniline in step (1) of the preparation method is replaced by an equivalent amount of 2,4-difluoroaniline, and the other raw materials and steps are the same as Example 51, and finally compound 63 is obtained (yield 79%).

[0250] Embodiment 64

[0251] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (64) above.

[0252] The difference between this example and Example 51 is that the 2,6-difluoroaniline in step (1) of the preparation method is replaced by an equivalent amount of 3,5-difluoroaniline, and the other raw materials and steps are the same as Example 51, and finally compound 64 is obtained (yield 73%).

[0253] Embodiment 65

[0254] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (65) above.

[0255] The difference between this example and Example 51 is that the 2,6-difluoroaniline in step (1) of the preparation method is replaced by an equivalent amount of o-chloroaniline, and the other raw materials and steps are the same as Example 51, and finally Compound 65 is obtained (yield 76%).

[0256] Embodiment 66

[0257] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (66) above.

[0258] The difference between this example and Example 51 is that the 2,6-difluoroaniline in step (1) of the preparation method is replaced by an equivalent amount of 3-chloroaniline, and the other raw materials and steps are the same as Example 51, and finally compound 66 is obtained (yield 76%).

[0259] Embodiment 67

[0260] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (67) above.

[0261] The difference between this example and Example 51 is that the 2,6-difluoroaniline in step (1) of the preparation method is replaced by an equivalent amount of 4-chloroaniline, and the other raw materials and steps are the same as Example 51, and finally compound 67 is obtained (yield 80%).

[0262] Embodiment 68

[0263] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (68) above.

[0264] The difference between this example and Example 51 is that the 2,6-difluoroaniline in step (1) of the preparation method is replaced by an equivalent amount of 2,6-dichloroaniline, and the other raw materials and steps are the same as Example 51, and finally Compound 68 is obtained (yield 77%).

[0265] Embodiment 69

[0266] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (69) above.

[0267] The difference between this example and Example 51 is that the 2,6-difluoroaniline in step (1) of the preparation method is replaced by an equivalent amount of 2,3-dichloroaniline, and the other raw materials and steps are the same as Example 51, and finally compound 69 is obtained (yield 73%).

[0268] Embodiment 70

[0269] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (70) above.

[0270] The difference between this example and Example 51 is that the 2,6-difluoroaniline in step (1) of the preparation method is replaced by an equivalent amount of 2,4-dichloroaniline, and the other raw materials and steps are the same as Example 51, and finally compound 70 is obtained (yield 73%).

[0271] Embodiment 71

[0272] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (71) above.

[0273] The difference between this example and Example 51 is that the 2,6-difluoroaniline in step (1) of the preparation method is replaced by an equivalent amount of 3,5-dichloroaniline, and the other raw materials and steps are the same as Example 51, and finally Compound 71 is obtained (yield 71%).

[0274] Embodiment 72

[0275] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (72) above.

[0276] The difference between this example and Example 51 is that the 2,6-difluoroaniline in step (1) of the preparation method is replaced by an equivalent amount of (4-chloro-2-methylphenyl)(methyl)sulfane, and the other raw materials and steps are the same as Example 51, and finally Compound 72 is obtained (yield 73%).

[0277] Embodiment 73

[0278] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (73) above.

[0279] The difference between this example and Example 51 is that the 2,6-difluoroaniline in step (1) of the preparation method is replaced by an equivalent amount of 3-chloro-2-methanesulfinylaniline, and the other raw materials and steps are the same as Example 51, and finally Compound 73 is obtained (yield 86%).

[0280] Embodiment 74

[0281] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (74) above.

[0282] The difference between this example and Example 51 is that the 2,6-difluoroaniline in step (1) of the preparation method is replaced by an equivalent amount of 3-aminobiphenyl, and the other raw materials and steps are the same as Example 51, and finally compound 74 is obtained (yield 88%).

[0283] Embodiment 75

[0284] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (75) above.

[0285] The difference between this example and Example 51 is that the 2,6-difluoroaniline in step (1) of the preparation method is replaced by an equivalent amount of [1,1':3',1''-terphenyl]-5'-amine, and the other raw materials and steps are the same as Example 51, and finally Compound 75 is obtained (yield 89%).

[0286] Embodiment 76

[0287] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (76) above.

[0288] The preparation method of the above compound comprises the following steps:

[0289] (1) In a 100 mL flask filled with argon, a mixture of 3,3'-dibromo-9,9'-spirobifluorene (4.74 g, 10.0 mmol), 2,6-difluoroaniline (2.84 g, 22.0 mmol), Pd2(dba)3 (0.18 g, 0.2 mol), tBu3PHBF4 (0.15 g, 0.5 mol), tBuONa (2.88 g, 30.0 mmol) and 50 mL of toluene was stirred at 110 °C overnight; the cooled mixture was filtered through celite and washed with dichloromethane to remove the organic solvent; the solid was further purified by silica gel flash column chromatography (eluted with petroleum ether / dichloromethane) to obtain intermediate 1 as a white solid (5.17 g, 9.0 mmol, yield 90%);

[0290] (2) to (3) were the same as (2) to (3) in Example 1, and compound 76 was finally obtained (yield 81%).

[0291] Embodiment 77

[0292] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (77) above.

[0293] The difference between this example and Example 76 is that the 2,6-difluoroaniline in step (1) of the preparation method is replaced by an equivalent amount of o-cyanoaniline, and the other raw materials and steps are the same as Example 76, and finally Compound 77 is obtained (yield 77%).

[0294] Embodiment 78

[0295] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (78) above.

[0296] The difference between this example and Example 76 is that the 2,6-difluoroaniline in step (1) of the preparation method is replaced by an equivalent amount of p-cyanoaniline, and the other raw materials and steps are the same as Example 76, and finally Compound 78 is obtained (yield 81%).

[0297] Embodiment 79

[0298] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (79) above.

[0299] The difference between this example and Example 76 is that the 2,6-difluoroaniline in step (1) of the preparation method is replaced with an equivalent amount of 2-aminoisophthalonitrile, and the other raw materials and steps are the same as Example 76, and finally Compound 79 is obtained (yield 83%).

[0300] Embodiment 80

[0301] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (80) above.

[0302] The difference between this example and Example 76 is that the 2,6-difluoroaniline in step (1) of the preparation method is replaced by an equivalent amount of 3-aminophthalonitrile, and the other raw materials and steps are the same as Example 76, and finally Compound 80 is obtained (yield 86%).

[0303] Embodiment 81

[0304] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (81) above.

[0305] The difference between this example and Example 76 is that the 2,6-difluoroaniline in step (1) of the preparation method is replaced by an equivalent amount of 4-aminoisophthalonitrile, and the other raw materials and steps are the same as Example 76, and finally Compound 81 is obtained (yield 81%).

[0306] Embodiment 82

[0307] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (82) above.

[0308] The difference between this example and Example 76 is that the 2,6-difluoroaniline in step (1) of the preparation method is replaced by an equivalent amount of 5-aminoisophthalonitrile, and the other raw materials and steps are the same as Example 76, and finally Compound 82 is obtained (yield 83%).

[0309] Embodiment 83

[0310] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (83) above.

[0311] The difference between this example and Example 76 is that the 2,6-difluoroaniline in step (1) of the preparation method is replaced with an equivalent amount of 2-fluoroaniline, and the other raw materials and steps are the same as Example 76, and finally Compound 83 is obtained (yield 77%).

[0312] Embodiment 84

[0313] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (84) above.

[0314] The difference between this example and Example 76 is that the 2,6-difluoroaniline in step (1) of the preparation method is replaced by an equivalent amount of 3-fluoroaniline, and the other raw materials and steps are the same as Example 76, and finally Compound 84 is obtained (yield 79%).

[0315] Embodiment 85

[0316] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (85) above.

[0317] The difference between this example and Example 76 is that the 2,6-difluoroaniline in step (1) of the preparation method is replaced by an equivalent amount of 4-fluoroaniline, and the other raw materials and steps are the same as Example 76, and finally Compound 85 is obtained (yield 84%).

[0318] Embodiment 86

[0319] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (86) above.

[0320] The difference between this example and Example 76 is that the 2,6-difluoroaniline in step (1) of the preparation method is replaced by an equivalent amount of methylamine, and the other raw materials and steps are the same as Example 76, and finally Compound 86 is obtained (yield 84%).

[0321] Embodiment 87

[0322] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (87) above.

[0323] The difference between this example and Example 76 is that the 2,6-difluoroaniline in step (1) of the preparation method is replaced with an equivalent amount of 2,3-difluoroaniline, and the other raw materials and steps are the same as Example 76, and finally Compound 87 is obtained (yield 76%).

[0324] Embodiment 88

[0325] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (88) above.

[0326] The difference between this example and Example 76 is that the 2,6-difluoroaniline in step (1) of the preparation method is replaced with an equivalent amount of 2,4-difluoroaniline, and the other raw materials and steps are the same as Example 76, and finally Compound 88 is obtained (yield 73%).

[0327] Embodiment 89

[0328] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (89) above.

[0329] The difference between this example and Example 76 is that the 2,6-difluoroaniline in step (1) of the preparation method is replaced with an equivalent amount of 3,5-difluoroaniline, and the other raw materials and steps are the same as Example 76, and finally Compound 89 is obtained (yield 79%).

[0330] Embodiment 90

[0331] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (90) above.

[0332] The difference between this example and Example 76 is that the 2,6-difluoroaniline in step (1) of the preparation method is replaced by an equivalent amount of o-chloroaniline, and the other raw materials and steps are the same as Example 76, and finally Compound 90 is obtained (yield 86%).

[0333] Embodiment 91

[0334] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (91) above.

[0335] The difference between this example and Example 76 is that the 2,6-difluoroaniline in step (1) of the preparation method is replaced by an equivalent amount of 3-chloroaniline, and the other raw materials and steps are the same as Example 76, and finally Compound 91 is obtained (yield 86%).

[0336] Embodiment 92

[0337] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (92) above.

[0338] The difference between this example and Example 76 is that the 2,6-difluoroaniline in step (1) of the preparation method is replaced by an equivalent amount of 4-chloroaniline, and the other raw materials and steps are the same as Example 76, and finally compound 92 is obtained (yield 81%).

[0339] Embodiment 93

[0340] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (93) above.

[0341] The difference between this example and Example 76 is that the 2,6-difluoroaniline in step (1) of the preparation method is replaced with an equivalent amount of 2,6-dichloroaniline, and the other raw materials and steps are the same as Example 76, and finally compound 93 is obtained (yield 73%).

[0342] Embodiment 94

[0343] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (94) above.

[0344] The difference between this example and Example 76 is that the 2,6-difluoroaniline in step (1) of the preparation method is replaced with an equivalent amount of 2,3-dichloroaniline, and the other raw materials and steps are the same as Example 76, and finally Compound 94 is obtained (yield 76%).

[0345] Embodiment 95

[0346] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (95) above.

[0347] The difference between this example and Example 76 is that the 2,6-difluoroaniline in step (1) of the preparation method is replaced by an equivalent amount of 2,4-dichloroaniline, and the other raw materials and steps are the same as Example 76, and finally Compound 95 is obtained (yield 79%).

[0348] Embodiment 96

[0349] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (96) above.

[0350] The difference between this example and Example 76 is that the 2,6-difluoroaniline in step (1) of the preparation method is replaced by an equivalent amount of 3,5-dichloroaniline, and the other raw materials and steps are the same as Example 76, and finally Compound 96 is obtained (yield 76%).

[0351] Embodiment 97

[0352] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (97) above.

[0353] The difference between this example and Example 76 is that the 2,6-difluoroaniline in step (1) of the preparation method is replaced by an equivalent amount of (4-chloro-2-methylphenyl)(methyl)sulfane, and the other raw materials and steps are the same as Example 76, and finally Compound 97 is obtained (yield 86%).

[0354] Embodiment 98

[0355] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (98) above.

[0356] The difference between this example and Example 76 is that the 2,6-difluoroaniline in step (1) of the preparation method is replaced by an equivalent amount of 3-chloro-2-methanesulfinylaniline, and the other raw materials and steps are the same as Example 76, and finally Compound 98 is obtained (yield 82%).

[0357] Embodiment 99

[0358] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (99) above.

[0359] The difference between this example and Example 76 is that the 2,6-difluoroaniline in step (1) of the preparation method is replaced with an equivalent amount of 3-aminobiphenyl, and the other raw materials and steps are the same as Example 76, and finally Compound 99 is obtained (yield 89%).

[0360] Embodiment 100

[0361] The spirobifluorene-based narrow emission compound of this embodiment has the structural formula (100) above.

[0362] The difference between this example and Example 76 is that the 2,6-difluoroaniline in step (1) of the preparation method is replaced by an equivalent amount of [1,1':3',1''-terphenyl]-5'-amine, and the other raw materials and steps are the same as Example 76, and finally compound 100 is obtained (yield 83%).

[0363] The compounds of Examples 1, 26, 51, and 76 were tested for solubility and thermodynamic stability. The specific test results are shown in Figure 1~Figure 2 .

[0364] Figure 1 These are the absorption and emission spectra of the compounds of Examples 1, 26, 51 and 76 of the present invention in toluene solution. Figure 2 The thermogravimetric analysis and differential scanning calorimetry curves of the compounds of Examples 1, 26, 51, and 76 of the present invention are shown in FIG. Figure 1~Figure 2 It can be seen that, after testing and verification, the narrow emission compound based on spirobifluorene prepared by the present invention is insensitive to water and oxygen, has good solubility in common organic solvents, and exhibits excellent thermodynamic stability and outstanding photochemical stability.

[0365] An organic electroluminescent device is prepared using the spirobifluorene-based narrow emission compound of Examples 1, 26, 51, and 76 and a conventional spirocyclic non-MR-TADF compound, wherein the electroluminescent device has the following binary sensitized OLED structure: glass substrate / indium tin oxide / TAPC (30 nanometers) / mCP (10 nanometers) / Xwt% compound (X=2 / 3 / 5 / 7): X'wt% DOBNA-oAr (30 nanometers, X+X'=100) / PPF (10 nanometers) / TmPyPB (40 nanometers) / lithium fluoride (1 nanometer) / aluminum (150 nanometers). Indium tin oxide is an anode, TAPC is a hole injection layer, mCP is a hole transport layer, Xwt% compound 1 (X=2 / 3 / 5 / 7): X'wt% DOBNA-oAr and PPF are light-emitting layers, TmPyPB is an electron transport layer, lithium fluoride is an electron injection layer, and aluminum is a cathode.

[0366] The structural formulas of TAPC, mCP, DOBNA-oAr, PPF and TmPyPB are as follows:

[0367] ;

[0368] The structural formula of the conventional spirocyclic non-MR-TADF compound is shown below:

[0369] .

[0370] The preparation method of the organic electroluminescent device is as follows: a transparent conductive indium tin oxide glass substrate is cleaned with a micron-grade semiconductor-specific detergent, deionized water, acetone, and isopropanol ultrasonic cleaning for 15 minutes in sequence to remove dirt on the substrate surface, and then placed in a constant temperature box for drying at 80°C for standby use; the dried ITO substrate is treated with oxygen-plasma for 5 minutes to further remove organic pollutants attached to the surface; finally, TAPC, mCP, compound, DOBNA-oAr, PPF, TmPyPB, lithium fluoride and aluminum are thermally deposited in sequence by vacuum thermal evaporation to obtain an organic electroluminescent device, and relevant performance tests are performed. The specific test results are shown in Figure 3~Figure 4 and Table 1.

[0371] Figure 3 It is the current density-voltage-brightness curve of the organic electroluminescent device prepared by the compounds of Examples 1, 26, 51 and 76 of the present invention. Figure 4 The external quantum efficiency-brightness curve and the luminescence spectrum of the organic electroluminescent device prepared by the compounds of Examples 1, 26, 51, and 76 of the present invention are shown in FIG. Figure 3~Figure 4 It can be seen that after the spirobifluorene-based narrow emission compound prepared in the present invention is prepared into an organic electroluminescent device, it exhibits high luminous efficiency and excellent performance of a narrow emission spectrum.

[0372] Table 1 External quantum efficiency data of electroluminescent devices

[0373] .

[0374] As can be seen from Table 1, the external quantum efficiency of the electroluminescent device prepared using the conventional spirocyclic non-MR-TADF (whose structural formula is as follows) is 10.59%, while the maximum external quantum efficiency of the organic electroluminescent device prepared using the spirobifluorene-based narrow emission compound prepared in the present invention can reach 35.5%, which is sufficient to prove its high external quantum efficiency.

[0375] The various aspects, embodiments, and features of the present invention should be considered to be illustrative in all aspects and not limiting of the present invention, the scope of which is defined solely by the claims. Other embodiments, modifications, and uses will be apparent to those skilled in the art without departing from the spirit and scope of the claimed invention.

[0376] In the preparation method of the present invention, the order of each step is not limited to the order listed. For those skilled in the art, without creative work, the order of each step is also within the protection scope of the present invention. In addition, two or more steps or actions can be performed simultaneously.

[0377] Finally, it should be noted that the specific embodiments described herein are merely examples of the present invention, and are not intended to limit the implementation methods of the present invention. A person skilled in the art of the present invention may make various modifications or supplements to the specific embodiments described, or replace them in a similar manner. It is not necessary and impossible to provide all examples of all implementation methods here. However, these obvious changes or modifications derived from the essential spirit of the present invention still fall within the scope of protection of the present invention, and interpreting them as any additional limitation is contrary to the spirit of the present invention.

Claims

1. A narrow emission compound based on spirobifluorene, characterized in that: The narrow emission compound has one of the following general structural formulas: ； Among them, R and R' are independently selected from one or more of hydrogen atoms, fluorine atoms, chlorine atoms, bromine atoms, cyano groups, alkyl groups, aromatic rings composed of carbon and hydrogen atoms, aromatic heterocycles composed of carbon, nitrogen and hydrogen atoms, aromatic heterocycles composed of carbon, nitrogen, oxygen and hydrogen atoms, aromatic heterocycles composed of carbon, sulfur and hydrogen atoms, and aromatic heterocycles composed of carbon, nitrogen, sulfur and hydrogen atoms.

2. A spirobifluorene-based narrow emission compound according to claim 1, characterized in that: The R and R' are independently selected from one of the following group structures I to XXV: 。 3. A spirobifluorene-based narrow emission compound according to claim 1, characterized in that: The narrow emission compound based on spirobifluorene has a structural formula of one of the following (1) to (100): 。 4. A method for preparing a narrow emission compound based on spirobifluorene according to any one of claims 1 to 3, characterized in that: The preparation method comprises the following steps: mixing spirobifluorene, an amine compound, a catalyst, an electron-rich ligand, a base and an organic solvent for a first reaction to obtain an intermediate 1; mixing the intermediate 1, 3-bromo-5-methyl-N,N-diphenylaniline, a catalyst, an electron-rich ligand, a base and an organic solvent for a second reaction to obtain an intermediate 2; and mixing the intermediate 2, a boron halide and an organic solvent for a third reaction to obtain the spirobifluorene-based narrow emission compound.

5. The preparation method according to claim 4, characterized in that: In the first reaction, the spirobifluorene includes one or more of 2,2'-dibromo-9,9'-spirobifluorene, 2,7-dibromo-9,9'-spirobifluorene, 3,6-dibromo-9,9'-spirobifluorene, and 3,3'-dibromo-9,9'-spirobifluorene; The amine compound in the first reaction includes one or more of 2,6-difluoroaniline, o-cyanoaniline, p-cyanoaniline, 2-aminoisophthalonitrile, 3-aminoo-o-phthalonitrile, 4-aminoisophthalonitrile, 5-aminoisophthalonitrile, 2-fluoroaniline, 3-fluoroaniline, 4-fluoroaniline, methylamine, 2,4-difluoroaniline, 3,5-difluoroaniline, o-chloroaniline, 3-chloroaniline, 4-chloroaniline, 2,6-dichloroaniline, 2,3-dichloroaniline, 2,4-dichloroaniline, 3,5-dichloroaniline, (4-chloro-2-methylphenyl)(methyl)sulfane, 3-chloro-2-methylsulfinylaniline, 3-aminobiphenyl, and [1,1':3',1''-terphenyl]-5'-amine; The catalyst in the first reaction and / or the second reaction is a palladium catalyst, including one or more of Pd2(dba)3, Pd(OAc)2, PdCl2(dppf), Pd(dba)2, Pd(PPh3)4; The electron-rich ligand in the first reaction and / or the second reaction comprises one or more of tBu3PHBF4, Xantphos, BINAP, P(t-Bu)3, dtbpf, and RuPhos; The base in the first reaction and / or the second reaction comprises one or more of tBuONa, Cs2CO3, tBuOK, DBU, DABCO, Et3N, DIPEA, K2CO3, Na2CO3, K3PO4, NaOH, and KOH; The boron halide in the third reaction includes one or more of boron bromide, boron chloride, and boron iodide.

6. The preparation method according to claim 4, characterized in that: In the first reaction, the ratio of spirobifluorene, amine compound, catalyst, electron-rich ligand, base and solvent is (5-15) mmol: (15-30) mmol: (0.1-0.5) mol: (0.1-1.0) mol: (10-50) mmol: (10-100) mL; In the second reaction, the ratio of the intermediate 1, 3-bromo-5-methyl-N,N-diphenylaniline, the catalyst, the electron-rich ligand, the base and the solvent is (1-10) mmol: (10-20) mmol: (0.1-0.5) mol: (0.1-1.0) mol: (10-50) mmol: (10-100) mL; In the third reaction, the ratio of intermediate 2, boron halide and solvent is (0.1-5) mmol: (10-20) mmol: (10-30) ml.

7. The preparation method according to claim 4, characterized in that: The reaction temperature of the first reaction is 100-150°C, and the reaction time is 10-30h; The reaction temperature of the second reaction is 100-150°C, and the reaction time is 10-30h; The reaction temperature of the third reaction is 180-220°C, and the reaction time is 30-50h; After the first reaction and the second reaction are completed, the reaction products are filtered and washed to remove the organic solvent, and purified by column chromatography; The third reaction is carried out in a sealed environment and / or under inert gas protection. After the third reaction is completed, ethanol is added to the reaction product at -20 to 0°C to terminate the reaction, the organic solvent is removed by vacuum concentration, and the product is purified by column chromatography.

8. An electroluminescent device, characterized in that: The structure of the electroluminescent device includes an organic functional layer unit, and the organic functional layer unit includes a spirobifluorene-based narrow emission compound as described in any one of claims 1 to 3.

9. An electroluminescent device according to claim 8, characterized in that: The electroluminescent device comprises the following structure: an ITO substrate, and an anode layer, an organic functional layer unit and a cathode layer sequentially formed on the ITO substrate; the organic functional layer unit comprises a hole injection layer, a hole transport layer, a light-emitting layer and an electron transport layer; the light-emitting layer comprises one or more narrow emission compounds based on spirobifluorene.

10. The method for preparing an electroluminescent device according to claim 9, characterized in that: The preparation method comprises the following steps: forming an anode layer, an organic functional layer unit and a cathode layer in sequence on an ITO substrate by means of thermal evaporation and / or spin coating.

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