A narrow-emission compound based on spirobifluorene and an electroluminescent device prepared therefrom

Abstract

The present invention belongs to the field of organic light-emitting materials, and relates to a narrow-emission compound based on spirobifluorene and an electroluminescent device prepared therefrom. The narrow-emission compound has one of the following structural general formulas:. The narrow-emission compound based on spirobifluorene provided by the present invention is based on a multi-resonant type TADF material system. Using spirobifluorene as the parent body, the two conjugated systems separated by the spiro ring bond can be customized into bipolar materials, which can reduce the device voltage; the spiro ring skeleton realizes a relatively rigid face-to-face configuration, which can achieve effective space charge transfer and a high photoluminescence quantum yield for the TADF luminescent material. The device based on this electroluminescent material has effectively improved the luminous efficiency and brightness, while taking into account the narrow-band emission advantage, meeting the development needs of the market for high-definition display technology.

Description

Technical Field

[0001] The present invention belongs to the field of organic light-emitting 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 lie in being almost unrestricted by shape, being able to be easily deposited on flexible substrates, and even achieving transparency and double-sided light emission. 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. Currently, those skilled in the art have explored various types of organic compounds, including but not limited to aromatic hydrocarbons, heterocycles, metal complexes, arylamines, and arylboranes, which are widely used in different generations of OLEDs. These OLEDs can be roughly divided into three generations according to different emission 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 emission pathway.

[0004] In the research of TADF materials, the traditional method is to design molecules with a donor-acceptor [D-A] type structure, and promote the intersystem crossing process from the singlet state to the triplet state through the twisted conformation inside the molecule, thereby improving the emission 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 has become particularly urgent to develop new OLED materials and device structures. An ideal new material should be able to maintain high-efficiency emission while overcoming the problem of the decrease in the fluorescence quantum yield caused by the twisted molecular configuration of traditional TADF materials, with the expectation of improving the stability and brightness of the material without sacrificing the emission 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 through 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] ;

[0010] Among them, R and R’ are independently selected from one or more of a hydrogen atom, a fluorine atom, a chlorine atom, a bromine atom, a cyano group, an alkyl group, an aromatic ring composed of carbon and hydrogen atoms, an aromatic heterocycle composed of carbon, nitrogen and hydrogen atoms, an aromatic heterocycle composed of carbon, nitrogen, oxygen and hydrogen atoms, an aromatic heterocycle composed of carbon, sulfur and hydrogen atoms, and an aromatic heterocycle composed of carbon, nitrogen, sulfur and hydrogen atoms.

[0011] Preferably, R and R’ are independently selected from one or more of a hydrogen atom, a fluorine atom, a chlorine atom, a bromine atom, a cyano group, a C1-C10 straight-chain alkyl group, a C1-C10 branched-chain alkyl group, a C3-C10 aromatic ring composed of carbon and hydrogen atoms, a C3-C10 aromatic heterocycle composed of carbon, nitrogen and hydrogen atoms, a C3-C10 aromatic heterocycle composed of carbon, nitrogen, oxygen and hydrogen atoms, a C3-C10 aromatic heterocycle composed of carbon, sulfur and hydrogen atoms, and a C3-C10 aromatic heterocycle composed of carbon, nitrogen, sulfur and hydrogen atoms.

[0012] Preferably, R and R’ are independently selected from the group structures of any one of the following I~XXV:

[0013] 。

[0014] R and R’ can be the same or different groups.

[0015] Preferably, the narrow-emission compound based on spirobifluorene has a structural formula of any one of the following (1)~(100): 。

[0017] The second object of the present invention is achieved by the following technical solutions:

[0018] A preparation method of a narrow-emission compound based on spirobifluorene, the preparation method comprising the following steps: mixing spirobifluorene, an amine compound, a catalyst, an electron-rich ligand, a base and an organic solvent and stirring for a first reaction to obtain intermediate 1; mixing intermediate 1, 3-bromo-5-methyl-N,N-diphenylaniline, a catalyst, an electron-rich ligand, a base and an organic solvent and stirring for a second reaction to obtain intermediate 2; mixing intermediate 2, boron halide and an organic solvent and stirring for a third reaction to obtain the narrow-emission compound based on spirobifluorene.

[0019] The narrow-emission compound based on spirobifluorene of the present invention uses spirobifluorene as a parent body, obtains its core skeleton intermediate through a series of Hartwig-Buchwald reactions, and is finally synthesized through a one-pot method.

[0020] 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.

[0021] Preferably, the amine compound in the first reaction includes one or more of 2,6-difluoroaniline, o-cyanoaniline, p-cyanoaniline, 2-aminoisophthalonitrile, 3-aminophthalonitrile, 4-aminoisophthalonitrile, 5-aminophthalonitrile, 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.

[0022] 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), and Pd(PPh3)4. More preferably, it is Pd2(dba)3.

[0023] The catalysts in the first reaction and the second reaction can be the same or different.

[0024] Preferably, the electron-rich ligand in the first reaction and / or the second reaction includes one or more of tBu3PHBF4, Xantphos, BINAP, P(t-Bu)3, dtbpf, and RuPhos. More preferably, it is one or two of tBu3PHBF4 and Xantphos.

[0025] The electron-rich ligands in the first reaction and the second reaction can be the same or different.

[0026] Preferably, the base in the first reaction and / or the second reaction includes one or more of tBuONa, Cs2CO3, tBuOK, DBU, DABCO, Et3N, DIPEA, K2CO3, Na2CO3, K3PO4, NaOH, and KOH.

[0027] The bases in the first reaction and the second reaction can be the same or different.

[0028] 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.

[0029] The organic solvents in the first reaction, the second reaction, and the third reaction can be the same or different.

[0030] Preferably, the boron halide in the third reaction includes one or more of boron bromide, boron chloride, and boron iodide. More preferably, it is boron bromide.

[0031] 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.

[0032] Preferably, the ratio of 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.

[0033] Preferably, the ratio of intermediate 2, boron halide, and solvent in the third reaction is (0.1~5) mmol: (10~20) mmol: (10~30) ml.

[0034] Preferably, the reaction temperature of the first reaction is 100~150 °C, and the reaction time is 10~30 h.

[0035] Preferably, the reaction temperature of the second reaction is 100~150 °C, and the reaction time is 10~30 h.

[0036] Preferably, the reaction temperature of the third reaction is 180~220 °C, and the reaction time is 30~50 h.

[0037] Preferably, after the first reaction and the second reaction are completed, the reaction product is filtered and washed to remove the organic solvent, and purified by column chromatography.

[0038] Preferably, the third reaction is carried out in a sealed environment and / or under inert gas protection. After the third reaction is completed, the reaction product is added with ethanol at -20~0 °C to terminate the reaction, the organic solvent is removed by vacuum concentration, and purified by column chromatography.

[0039] The third object of the present invention is achieved by the following technical solutions:

[0040] 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.

[0041] Preferably, the electroluminescent device comprises the following structure: an ITO substrate, and an organic functional layer unit and a cathode layer sequentially formed on the ITO substrate.

[0042] 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.

[0043] 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.

[0044] The fourth object of the present invention is achieved by the following technical solutions:

[0045] A method for preparing an electroluminescent device comprises the following steps: forming 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.

[0046] Compared with the prior art, the present invention has the following beneficial effects:

[0047] 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.

[0048] 2. A narrow-emission compound based on spirobifluorene provided by the present invention, by introducing functional groups on the spirofluorene core, while maintaining the characteristics of its narrow-band emission, significantly enhances the electron transport ability of the material. This improvement is particularly important for the preparation of efficient narrow-band blue OLED devices and can significantly improve the overall performance of the devices. Specifically, the present invention simultaneously introduces symmetric functional groups on both sides of the spirofluorene molecule, effectively hindering the extension of the intramolecular conjugated structure, resulting in a deep blue emission wavelength. In addition, the compound also significantly improves the luminescence efficiency of the material through a multi-channel radiative decay process and an effective energy transfer mechanism. These characteristics work together, making the compound show excellent potential in the preparation of high-performance narrow-band OLED devices and significantly improving the working efficiency and service life of the devices.

[0049] 3. A narrow-emission compound based on spirobifluorene provided by the present invention has excellent thermal stability. Through an optimized molecular structure, it ensures the stability and reliability of the material under high-temperature conditions, which is crucial for extending the service life of the devices; through fine-tuning the molecular design, it realizes effective control of the luminescence spectral width, ensures the characteristics of narrow-band emission, and helps to obtain a light source with high color purity; by optimizing the transport balance of electrons and holes, it significantly improves the external quantum efficiency of the electroluminescent device, thereby reducing energy consumption while increasing the luminescence intensity. In addition, the electroluminescent device prepared using this compound can significantly improve the external quantum efficiency on the premise of effectively controlling the full width at half maximum (FWHM).

[0050] 4. The present invention provides a narrow-emission compound based on spirobifluorene. By changing the modifying groups on the aromatic structure, it can significantly improve the physical and chemical properties of the material, thus showing more excellent performance in organic semiconductor devices. The present invention not only optimizes the basic physical and chemical properties of the material but also shows more excellent comprehensive performance in organic semiconductor devices, providing new material options and technical support for the development of high-performance OLED devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 are the absorption and emission spectra of the compounds of Examples 1, 26, 51, and 76 of the present invention in toluene solution.

[0052] Figure 2 are the thermogravimetric analysis curves of the compounds of Examples 1, 26, 51, and 76 of the present invention.

[0053] Figure 3 are the current density-voltage-luminance curves of the organic electroluminescent devices prepared from the compounds of Examples 1, 26, 51, and 76 of the present invention.

[0054] Figure 4External quantum efficiency - luminance curves and emission spectra of the organic light - emitting devices prepared from the compounds of Embodiments 1, 26, 51, and 76 of the present invention. Detailed implementation manners

[0055] The following describes the technical solutions of the present invention in further detail in conjunction with specific embodiments. It should be understood that the specific embodiments described herein are only for explaining the present invention and not for limiting 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 appended claims of this application.

[0056] Embodiment 1

[0057] The spirobifluorene - based narrow - emission compound of this embodiment has the structural formula of (1) above, and its synthesis route is as follows:

[0058] ;

[0059] The preparation method of the above - mentioned compound includes the following steps:

[0060] (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 mmol), tBu3PHBF4 (0.15 g, 0.5 mmol), tBuONa (2.88 g, 30.0 mmol) and 50 mL of toluene was stirred overnight at 110 °C; the cooled mixture was filtered through diatomaceous earth and washed with dichloromethane to remove the organic solvent; the solid was further purified by flash column chromatography on silica gel (eluted with petroleum ether / dichloromethane) to obtain Intermediate 1 as a white solid (5.13 g, 9.0 mmol, yield 90%);

[0061] (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 mmol), Xantphos (0.12 g, 0.25 mmol), tBuONa (1.44 g, 15.0 mmol) and 50 mL of toluene was vigorously stirred overnight at 120 °C; after cooling to room temperature, the mixture was filtered through diatomaceous earth and washed with dichloromethane to remove the organic solvent; the solid was further purified by flash column chromatography on silica gel (eluted with petroleum ether / dichloromethane) to obtain Intermediate 2 as a white solid (4.34 g, 4.0 mmol, yield 80%);

[0062] (3) Add intermediate 2 (1.09 g, 1.0 mmol) and 15 mL of ortho-dichlorobenzene (o-DCB) into a 120 mL sealed tube under argon protection; after adding boron tribromide (3.00 g, 12.0 mmol), seal the sealed tube and stir the reaction at 200 °C for 36 h; after cooling to room temperature, slowly add ethanol (5.0 mL) to terminate the reaction in an ice bath; concentrate the organic solvent under vacuum, and purify the remaining solid by flash column chromatography on silica gel (eluted with petroleum ether / dichloromethane) to obtain compound 1, which is a bright yellow solid (0.83 g, 0.75 mmol, yield 75%).

[0063] Example 2

[0064] The narrow emission compound based on spirobifluorene in this example has the structural formula of the above (2).

[0065] The difference between this example and Example 1 is that 2,6-difluoroaniline in the first step of the preparation method is replaced with an equivalent amount of o-cyanoaniline, and other raw materials and steps are the same as those in Example 1, and finally compound 2 is obtained (yield 75%).

[0066] Example 3

[0067] The narrow emission compound based on spirobifluorene in this example has the structural formula of the above (3).

[0068] The difference between this example and Example 1 is that 2,6-difluoroaniline in the first step of the preparation method is replaced with an equivalent amount of p-cyanoaniline, and other raw materials and steps are the same as those in Example 1, and finally compound 3 is obtained (yield 70%).

[0069] Example 4

[0070] The narrow emission compound based on spirobifluorene in this example has the structural formula of the above (4).

[0071] The difference between this example and Example 1 is that 2,6-difluoroaniline in the first step of the preparation method is replaced with an equivalent amount of 2-aminoisophthalonitrile, and other raw materials and steps are the same as those in Example 1, and finally compound 4 is obtained (yield 76%).

[0072] Example 5

[0073] The narrow emission compound based on spirobifluorene in this example has the structural formula of the above (5).

[0074] The difference between this example and Example 1 is that 2,6-difluoroaniline in the first step of the preparation method is replaced with an equivalent amount of 3-aminophthalonitrile, and other raw materials and steps are the same as those in Example 1, and finally compound 5 is obtained (yield 74%).

[0075] Example 6

[0076] The narrow emission compound based on spirobifluorene in this example has the structural formula of the above (6).

[0077] The difference between this example and Example 1 is that 2,6-difluoroaniline in the first step (1) of the preparation method is replaced with an equivalent amount of 4-aminoisophthalonitrile, and other raw materials and steps are the same as those in Example 1. Finally, compound 6 is obtained (yield 71%).

[0078] Example 7

[0079] The narrow emission compound based on spirobifluorene in this example has the structural formula of the above (7).

[0080] The difference between this example and Example 1 is that 2,6-difluoroaniline in the first step (1) of the preparation method is replaced with an equivalent amount of 5-aminophthalonitrile, and other raw materials and steps are the same as those in Example 1. Finally, compound 7 is obtained (yield 72%).

[0081] Example 8

[0082] The narrow emission compound based on spirobifluorene in this example has the structural formula of the above (8).

[0083] The difference between this example and Example 1 is that 2,6-difluoroaniline in the first step (1) of the preparation method is replaced with an equivalent amount of 2-fluoroaniline, and other raw materials and steps are the same as those in Example 1. Finally, compound 8 is obtained (yield 70%).

[0084] Example 9

[0085] The narrow emission compound based on spirobifluorene in this example has the structural formula of the above (9).

[0086] The difference between this example and Example 1 is that 2,6-difluoroaniline in the first step (1) of the preparation method is replaced with an equivalent amount of 3-fluoroaniline, and other raw materials and steps are the same as those in Example 1. Finally, compound 9 is obtained (yield 72%).

[0087] Example 10

[0088] The narrow emission compound based on spirobifluorene in this example has the structural formula of the above (10).

[0089] The difference between this example and Example 1 is that 2,6-difluoroaniline in the first step (1) of the preparation method is replaced with an equivalent amount of 4-fluoroaniline, and other raw materials and steps are the same as those in Example 1. Finally, compound 10 is obtained (yield 78%).

[0090] Example 11

[0091] The narrow emission compound based on spirobifluorene in this example has the structural formula of (11) above.

[0092] The difference between this example and Example 1 is that 2,6-difluoroaniline in the first step of the preparation method is replaced with an equivalent amount of methylamine, and other raw materials and steps are the same as those in Example 1. Finally, compound 11 is obtained (yield 76%).

[0093] Example 12

[0094] The narrow emission compound based on spirobifluorene in this example has the structural formula of (12) above.

[0095] The difference between this example and Example 1 is that 2,6-difluoroaniline in the first step of the preparation method is replaced with an equivalent amount of 2,3-difluoroaniline, and other raw materials and steps are the same as those in Example 1. Finally, compound 12 is obtained (yield 71%).

[0096] Example 13

[0097] The narrow emission compound based on spirobifluorene in this example has the structural formula of (13) above.

[0098] The difference between this example and Example 1 is that 2,6-difluoroaniline in the first step of the preparation method is replaced with an equivalent amount of 2,4-difluoroaniline, and other raw materials and steps are the same as those in Example 1. Finally, compound 13 is obtained (yield 78%).

[0099] Example 14

[0100] The narrow emission compound based on spirobifluorene in this example has the structural formula of (14) above.

[0101] The difference between this example and Example 1 is that 2,6-difluoroaniline in the first step of the preparation method is replaced with an equivalent amount of 3,5-difluoroaniline, and other raw materials and steps are the same as those in Example 1. Finally, compound 14 is obtained (yield 72%).

[0102] Example 15

[0103] The narrow emission compound based on spirobifluorene in this example has the structural formula of (15) above.

[0104] The difference between this example and Example 1 is that 2,6-difluoroaniline in the first step of the preparation method is replaced with an equivalent amount of o-chloroaniline, and other raw materials and steps are the same as those in Example 1. Finally, compound 15 is obtained (yield 77%).

[0105] Example 16

[0106] The narrow emission compound based on spirobifluorene in this example has the structural formula of (16) above.

[0107] The difference between this example and Example 1 is that 2,6-difluoroaniline in step (1) of the preparation method is replaced with an equivalent amount of 3-chloroaniline, and other raw materials and steps are the same as those in Example 1, and finally Compound 16 is obtained (yield 70%).

[0108] Example 17

[0109] The narrow-emission compound based on spirobifluorene in this example has the structural formula of the above (17).

[0110] The difference between this example and Example 1 is that 2,6-difluoroaniline in step (1) of the preparation method is replaced with an equivalent amount of 4-chloroaniline, and other raw materials and steps are the same as those in Example 1, and finally Compound 17 is obtained (yield 77%).

[0111] Example 18

[0112] The narrow-emission compound based on spirobifluorene in this example has the structural formula of the above (18).

[0113] The difference between this example and Example 1 is that 2,6-difluoroaniline in step (1) of the preparation method is replaced with an equivalent amount of 2,6-dichloroaniline, and other raw materials and steps are the same as those in Example 1, and finally Compound 18 is obtained (yield 71%).

[0114] Example 19

[0115] The narrow-emission compound based on spirobifluorene in this example has the structural formula of the above (19).

[0116] The difference between this example and Example 1 is that 2,6-difluoroaniline in step (1) of the preparation method is replaced with an equivalent amount of 2,3-dichloroaniline, and other raw materials and steps are the same as those in Example 1, and finally Compound 19 is obtained (yield 74%).

[0117] Example 20

[0118] The narrow-emission compound based on spirobifluorene in this example has the structural formula of the above (20).

[0119] The difference between this example and Example 1 is that 2,6-difluoroaniline in step (1) of the preparation method is replaced with an equivalent amount of 2,4-dichloroaniline, and other raw materials and steps are the same as those in Example 1, and finally Compound 20 is obtained (yield 72%).

[0120] Example 21

[0121] The narrow-emission compound based on spirobifluorene in this example has the structural formula of the above (21).

[0122] The difference between this example and Example 1 lies in that 2,6-difluoroaniline in step (1) of the preparation method is replaced with an equivalent amount of 3,5-dichloroaniline, and other raw materials and steps are the same as those in Example 1, and finally compound 21 (yield 76%) is obtained.

[0123] Example 22

[0124] The narrow emission compound based on spirobifluorene in this example has the structural formula of the above (22).

[0125] The difference between this example and Example 1 lies in that 2,6-difluoroaniline in step (1) of the preparation method is replaced with an equivalent amount of (4-chloro-2-methylphenyl)(methyl)sulfane, and other raw materials and steps are the same as those in Example 1, and finally compound 22 (yield 73%) is obtained.

[0126] Example 23

[0127] The narrow emission compound based on spirobifluorene in this example has the structural formula of the above (23).

[0128] The difference between this example and Example 1 lies in that 2,6-difluoroaniline in step (1) of the preparation method is replaced with an equivalent amount of 3-chloro-2-methylsulfinylaniline, and other raw materials and steps are the same as those in Example 1, and finally compound 23 (yield 69%) is obtained.

[0129] Example 24

[0130] The narrow emission compound based on spirobifluorene in this example has the structural formula of the above (24).

[0131] The difference between this example and Example 1 lies in that 2,6-difluoroaniline in step (1) of the preparation method is replaced with an equivalent amount of 3-aminobiphenyl, and other raw materials and steps are the same as those in Example 1, and finally compound 24 (yield 78%) is obtained.

[0132] Example 25

[0133] The narrow emission compound based on spirobifluorene in this example has the structural formula of the above (25).

[0134] The difference between this example and Example 1 lies in that 2,6-difluoroaniline in step (1) of the preparation method is replaced with an equivalent amount of [1,1':3',1''-terphenyl]-5'-amine, and other raw materials and steps are the same as those in Example 26, and finally compound 25 (yield 71%) is obtained.

[0135] Example 26

[0136] The narrow emission compound based on spirobifluorene in this example has the structural formula of the above (26).

[0137] The preparation method of the above compound comprises the following steps:

[0138] (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 overnight at 110 °C; the cooled mixture was filtered through diatomaceous earth and washed with dichloromethane to remove the organic solvent; the solid was further purified by flash column chromatography on silica gel (eluted with petroleum ether / dichloromethane) to obtain Intermediate 1 as a white solid (5.11 g, 9.0 mmol, yield 90%);

[0139] (2)-(3) are the same as (2)-(3) in Example 1, and finally Compound 26 was obtained (yield 72%).

[0140] Example 27

[0141] The spirobifluorene-based narrow emission compound of this example has the structural formula of the above (27).

[0142] The difference between this example and Example 26 is that 2,6-difluoroaniline in step (1) of the preparation method was replaced with an equivalent amount of o-cyanoaniline, and other raw materials and steps were the same as those in Example 26, and finally Compound 27 was obtained (yield 75%).

[0143] Example 28

[0144] The spirobifluorene-based narrow emission compound of this example has the structural formula of the above (28).

[0145] The difference between this example and Example 26 is that 2,6-difluoroaniline in step (1) of the preparation method was replaced with an equivalent amount of p-cyanoaniline, and other raw materials and steps were the same as those in Example 26, and finally Compound 28 was obtained (yield 78%).

[0146] Example 29

[0147] The spirobifluorene-based narrow emission compound of this example has the structural formula of the above (29).

[0148] The difference between this example and Example 26 is that 2,6-difluoroaniline in step (1) of the preparation method was replaced with an equivalent amount of 2-aminoisophthalonitrile, and other raw materials and steps were the same as those in Example 26, and finally Compound 29 was obtained (yield 71%).

[0149] Example 30

[0150] The narrow emission compound based on spirobifluorene of this embodiment has the structural formula of the above (30).

[0151] The difference between this embodiment and Embodiment 26 is that 2,6-difluoroaniline in the first step of the preparation method is replaced with an equivalent amount of 3-aminophthalonitrile, and other raw materials and steps are the same as those in Embodiment 26, and finally Compound 30 is obtained (yield 76%).

[0152] Example 31

[0153] The narrow emission compound based on spirobifluorene of this embodiment has the structural formula of the above (31).

[0154] The difference between this embodiment and Embodiment 26 is that 2,6-difluoroaniline in the first step of the preparation method is replaced with an equivalent amount of 4-aminoisophthalonitrile, and other raw materials and steps are the same as those in Embodiment 26, and finally Compound 31 is obtained (yield 71%).

[0155] Example 32

[0156] The narrow emission compound based on spirobifluorene of this embodiment has the structural formula of the above (32).

[0157] The difference between this embodiment and Embodiment 26 is that 2,6-difluoroaniline in the first step of the preparation method is replaced with an equivalent amount of 5-aminoisophthalic acid nitrile, and other raw materials and steps are the same as those in Embodiment 26, and finally Compound 32 is obtained (yield 73%).

[0158] Example 33

[0159] The narrow emission compound based on spirobifluorene of this embodiment has the structural formula of the above (33).

[0160] The difference between this embodiment and Embodiment 26 is that 2,6-difluoroaniline in the first step of the preparation method is replaced with an equivalent amount of 2-fluoroaniline, and other raw materials and steps are the same as those in Embodiment 26, and finally Compound 33 is obtained (yield 74%).

[0161] Example 34

[0162] The narrow emission compound based on spirobifluorene of this embodiment has the structural formula of the above (34).

[0163] The difference between this embodiment and Embodiment 26 is that 2,6-difluoroaniline in the first step of the preparation method is replaced with an equivalent amount of 3-fluoroaniline, and other raw materials and steps are the same as those in Embodiment 26, and finally Compound 34 is obtained (yield 80%).

[0164] Example 35

[0165] The narrow emission compound based on spirobifluorene of this embodiment has the structural formula of the above (35).

[0166] The difference between this embodiment and Embodiment 26 is that 2,6-difluoroaniline in the first step of the preparation method is replaced with an equivalent amount of 4-fluoroaniline, and other raw materials and steps are the same as those in Embodiment 26, and finally Compound 35 is obtained (yield 83%).

[0167] Embodiment 36

[0168] The narrow emission compound based on spirobifluorene of this embodiment has the structural formula of the above (36).

[0169] The difference between this embodiment and Embodiment 26 is that 2,6-difluoroaniline in the first step of the preparation method is replaced with an equivalent amount of methylamine, and other raw materials and steps are the same as those in Embodiment 26, and finally Compound 36 is obtained (yield 71%).

[0170] Embodiment 37

[0171] The narrow emission compound based on spirobifluorene of this embodiment has the structural formula of the above (37).

[0172] The difference between this embodiment and Embodiment 26 is that 2,6-difluoroaniline in the first step of the preparation method is replaced with an equivalent amount of 2,3-difluoroaniline, and other raw materials and steps are the same as those in Embodiment 26, and finally Compound 37 is obtained (yield 76%).

[0173] Embodiment 38

[0174] The narrow emission compound based on spirobifluorene of this embodiment has the structural formula of the above (38).

[0175] The difference between this embodiment and Embodiment 26 is that 2,6-difluoroaniline in the first step of the preparation method is replaced with an equivalent amount of 2,4-difluoroaniline, and other raw materials and steps are the same as those in Embodiment 26, and finally Compound 38 is obtained (yield 73%).

[0176] Embodiment 39

[0177] The narrow emission compound based on spirobifluorene of this embodiment has the structural formula of the above (39).

[0178] The difference between this embodiment and Embodiment 26 is that 2,6-difluoroaniline in the first step of the preparation method is replaced with an equivalent amount of 3,5-difluoroaniline, and other raw materials and steps are the same as those in Embodiment 26, and finally Compound 39 is obtained (yield 75%).

[0179] Embodiment 40

[0180] The narrow emission compound based on spirobifluorene of this embodiment has the structural formula of the above (40).

[0181] The difference between this example and Example 26 is that 2,6-difluoroaniline in the first step of the preparation method is replaced with an equivalent amount of o-chloroaniline, and other raw materials and steps are the same as those in Example 26, and finally Compound 40 (yield 79%) is obtained.

[0182] Example 41

[0183] The narrow-emission compound based on spirobifluorene in this example has the structural formula of the above (41).

[0184] The difference between this example and Example 26 is that 2,6-difluoroaniline in the first step of the preparation method is replaced with an equivalent amount of 3-chloroaniline, and other raw materials and steps are the same as those in Example 26, and finally Compound 41 (yield 74%) is obtained.

[0185] Example 42

[0186] The narrow-emission compound based on spirobifluorene in this example has the structural formula of the above (42).

[0187] The difference between this example and Example 26 is that 2,6-difluoroaniline in the first step of the preparation method is replaced with an equivalent amount of 4-chloroaniline, and other raw materials and steps are the same as those in Example 26, and finally Compound 42 (yield 77%) is obtained.

[0188] Example 43

[0189] The narrow-emission compound based on spirobifluorene in this example has the structural formula of the above (43).

[0190] The difference between this example and Example 26 is that 2,6-difluoroaniline in the first step of the preparation method is replaced with an equivalent amount of 2,6-dichloroaniline, and other raw materials and steps are the same as those in Example 26, and finally Compound 43 (yield 76%) is obtained.

[0191] Example 44

[0192] The narrow-emission compound based on spirobifluorene in this example has the structural formula of the above (44).

[0193] The difference between this example and Example 26 is that 2,6-difluoroaniline in the first step of the preparation method is replaced with an equivalent amount of 2,3-dichloroaniline, and other raw materials and steps are the same as those in Example 26, and finally Compound 44 (yield 79%) is obtained.

[0194] Example 45

[0195] The narrow-emission compound based on spirobifluorene in this example has the structural formula of the above (45).

[0196] The difference between this example and Example 26 is that 2,6-difluoroaniline in step (1) of the preparation method is replaced with an equivalent amount of 2,4-dichloroaniline, and other raw materials and steps are the same as those in Example 26, and finally compound 45 is obtained (yield 86%).

[0197] Example 46

[0198] The narrow emission compound based on spirobifluorene in this example has the structural formula of the above (46).

[0199] The difference between this example and Example 26 is that 2,6-difluoroaniline in step (1) of the preparation method is replaced with an equivalent amount of 3,5-dichloroaniline, and other raw materials and steps are the same as those in Example 26, and finally compound 46 is obtained (yield 70%).

[0200] Example 47

[0201] The narrow emission compound based on spirobifluorene in this example has the structural formula of the above (47).

[0202] The difference between this example and Example 26 is that 2,6-difluoroaniline in step (1) of the preparation method is replaced with an equivalent amount of (4-chloro-2-methylphenyl)(methyl)sulfane, and other raw materials and steps are the same as those in Example 26, and finally compound 47 is obtained (yield 76%).

[0203] Example 48

[0204] The narrow emission compound based on spirobifluorene in this example has the structural formula of the above (48).

[0205] The difference between this example and Example 26 is that 2,6-difluoroaniline in step (1) of the preparation method is replaced with an equivalent amount of 3-chloro-2-methylsulfinylaniline, and other raw materials and steps are the same as those in Example 26, and finally compound 48 is obtained (yield 79%).

[0206] Example 49

[0207] The narrow emission compound based on spirobifluorene in this example has the structural formula of the above (49).

[0208] The difference between this example and Example 26 is that 2,6-difluoroaniline in step (1) of the preparation method is replaced with an equivalent amount of 3-aminobiphenyl, and other raw materials and steps are the same as those in Example 26, and finally compound 49 is obtained (yield 76%).

[0209] Example 50

[0210] The narrow emission compound based on spirobifluorene in this example has the structural formula of the above (50).

[0211] The difference between this example and Example 26 is that 2,6-difluoroaniline in step (1) of the preparation method is replaced with an equivalent amount of [1,1':3',1''-terphenyl]-5'-amine, and other raw materials and steps are the same as those in Example 26, and finally Compound 50 is obtained (yield 80%).

[0212] Example 51

[0213] The narrow emission compound based on spirobifluorene in this example has the structural formula of the above (51).

[0214] The preparation method of the above compound includes the following steps:

[0215] (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 overnight at 110 °C; the cooled mixture was filtered through diatomaceous earth and washed with dichloromethane to remove the organic solvent; the solid was further purified by flash column chromatography on silica gel (eluted with petroleum ether / dichloromethane) to obtain Intermediate 1 as a white solid (5.15 g, 9.0 mmol, yield 90%);

[0216] (2) - (3) are the same as (2) - (3) in Example 1, and finally Compound 51 is obtained (yield 76%).

[0217] Example 52

[0218] The narrow emission compound based on spirobifluorene in this example has the structural formula of the above (52).

[0219] The difference between this example and Example 51 is that 2,6-difluoroaniline in step (1) of the preparation method is replaced with an equivalent amount of o-cyanoaniline, and other raw materials and steps are the same as those in Example 51, and finally Compound 52 is obtained (yield 76%).

[0220] Example 53

[0221] The narrow emission compound based on spirobifluorene in this example has the structural formula of the above (53).

[0222] The difference between this example and Example 51 is that 2,6-difluoroaniline in step (1) of the preparation method is replaced with an equivalent amount of p-cyanoaniline, and other raw materials and steps are the same as those in Example 51, and finally Compound 53 is obtained (yield 79%).

[0223] Example 54

[0224] The narrow emission compound based on spirobifluorene of this embodiment has the structural formula of the above (54).

[0225] The difference between this embodiment and Embodiment 51 is that 2,6-difluoroaniline in the first step of the preparation method is replaced with an equivalent amount of 2-aminoisophthalonitrile, and other raw materials and steps are the same as those in Embodiment 51, and finally Compound 54 is obtained (yield 73%).

[0226] Embodiment 55

[0227] The narrow emission compound based on spirobifluorene of this embodiment has the structural formula of the above (55).

[0228] The difference between this embodiment and Embodiment 51 is that 2,6-difluoroaniline in the first step of the preparation method is replaced with an equivalent amount of 3-aminophthalonitrile, and other raw materials and steps are the same as those in Embodiment 51, and finally Compound 55 is obtained (yield 80%).

[0229] Embodiment 56

[0230] The narrow emission compound based on spirobifluorene of this embodiment has the structural formula of the above (56).

[0231] The difference between this embodiment and Embodiment 51 is that 2,6-difluoroaniline in the first step of the preparation method is replaced with an equivalent amount of 4-aminoisophthalonitrile, and other raw materials and steps are the same as those in Embodiment 51, and finally Compound 56 is obtained (yield 79%).

[0232] Embodiment 57

[0233] The narrow emission compound based on spirobifluorene of this embodiment has the structural formula of the above (57).

[0234] The difference between this embodiment and Embodiment 51 is that 2,6-difluoroaniline in the first step of the preparation method is replaced with an equivalent amount of 5-aminophthalic acid nitrile, and other raw materials and steps are the same as those in Embodiment 51, and finally Compound 57 is obtained (yield 76%).

[0235] Embodiment 58

[0236] The narrow emission compound based on spirobifluorene of this embodiment has the structural formula of the above (58).

[0237] The difference between this embodiment and Embodiment 51 is that 2,6-difluoroaniline in the first step of the preparation method is replaced with an equivalent amount of 2-fluoroaniline, and other raw materials and steps are the same as those in Embodiment 51, and finally Compound 58 is obtained (yield 76%).

[0238] Embodiment 59

[0239] The narrow emission compound based on spirobifluorene of this embodiment has the structural formula of the above (59).

[0240] The difference between this embodiment and Embodiment 51 is that 2,6-difluoroaniline in the first step of the preparation method is replaced with an equivalent amount of 3-fluoroaniline, and other raw materials and steps are the same as those in Embodiment 51, and finally Compound 59 is obtained (yield 76%).

[0241] Embodiment 60

[0242] The narrow emission compound based on spirobifluorene of this embodiment has the structural formula of the above (60).

[0243] The difference between this embodiment and Embodiment 51 is that 2,6-difluoroaniline in the first step of the preparation method is replaced with an equivalent amount of 4-fluoroaniline, and other raw materials and steps are the same as those in Embodiment 51, and finally Compound 60 is obtained (yield 86%).

[0244] Embodiment 61

[0245] The narrow emission compound based on spirobifluorene of this embodiment has the structural formula of the above (61).

[0246] The difference between this embodiment and Embodiment 51 is that 2,6-difluoroaniline in the first step of the preparation method is replaced with an equivalent amount of methylamine, and other raw materials and steps are the same as those in Embodiment 51, and finally Compound 61 is obtained (yield 73%).

[0247] Embodiment 62

[0248] The narrow emission compound based on spirobifluorene of this embodiment has the structural formula of the above (62).

[0249] The difference between this embodiment and Embodiment 51 is that 2,6-difluoroaniline in the first step of the preparation method is replaced with an equivalent amount of 2,3-difluoroaniline, and other raw materials and steps are the same as those in Embodiment 51, and finally Compound 62 is obtained (yield 73%).

[0250] Embodiment 63

[0251] The narrow emission compound based on spirobifluorene of this embodiment has the structural formula of the above (63).

[0252] The difference between this embodiment and Embodiment 51 is that 2,6-difluoroaniline in the first step of the preparation method is replaced with an equivalent amount of 2,4-difluoroaniline, and other raw materials and steps are the same as those in Embodiment 51, and finally Compound 63 is obtained (yield 79%).

[0253] Embodiment 64

[0254] The narrow emission compound based on spirobifluorene of this embodiment has the structural formula of the above (64).

[0255] The difference between this example and Example 51 is that 2,6-difluoroaniline in step (1) of the preparation method is replaced with an equivalent amount of 3,5-difluoroaniline, and other raw materials and steps are the same as those in Example 51, and finally Compound 64 (yield 73%) is obtained.

[0256] Example 65

[0257] The narrow emission compound based on spirobifluorene in this example has the structural formula of the above (65).

[0258] The difference between this example and Example 51 is that 2,6-difluoroaniline in step (1) of the preparation method is replaced with an equivalent amount of o-chloroaniline, and other raw materials and steps are the same as those in Example 51, and finally Compound 65 (yield 76%) is obtained.

[0259] Example 66

[0260] The narrow emission compound based on spirobifluorene in this example has the structural formula of the above (66).

[0261] The difference between this example and Example 51 is that 2,6-difluoroaniline in step (1) of the preparation method is replaced with an equivalent amount of 3-chloroaniline, and other raw materials and steps are the same as those in Example 51, and finally Compound 66 (yield 76%) is obtained.

[0262] Example 67

[0263] The narrow emission compound based on spirobifluorene in this example has the structural formula of the above (67).

[0264] The difference between this example and Example 51 is that 2,6-difluoroaniline in step (1) of the preparation method is replaced with an equivalent amount of 4-chloroaniline, and other raw materials and steps are the same as those in Example 51, and finally Compound 67 (yield 80%) is obtained.

[0265] Example 68

[0266] The narrow emission compound based on spirobifluorene in this example has the structural formula of the above (68).

[0267] The difference between this example and Example 51 is that 2,6-difluoroaniline in step (1) of the preparation method is replaced with an equivalent amount of 2,6-dichloroaniline, and other raw materials and steps are the same as those in Example 51, and finally Compound 68 (yield 77%) is obtained.

[0268] Example 69

[0269] The narrow emission compound based on spirobifluorene in this example has the structural formula of the above (69).

[0270] The difference between this example and Example 51 is that 2,6-difluoroaniline in step (1) of the preparation method is replaced with an equivalent amount of 2,3-dichloroaniline, and other raw materials and steps are the same as those in Example 51. Finally, compound 69 (yield 73%) is obtained.

[0271] Example 70

[0272] The narrow emission compound based on spirobifluorene in this example has the structural formula of the above (70).

[0273] The difference between this example and Example 51 is that 2,6-difluoroaniline in step (1) of the preparation method is replaced with an equivalent amount of 2,4-dichloroaniline, and other raw materials and steps are the same as those in Example 51. Finally, compound 70 (yield 73%) is obtained.

[0274] Example 71

[0275] The narrow emission compound based on spirobifluorene in this example has the structural formula of the above (71).

[0276] The difference between this example and Example 51 is that 2,6-difluoroaniline in step (1) of the preparation method is replaced with an equivalent amount of 3,5-dichloroaniline, and other raw materials and steps are the same as those in Example 51. Finally, compound 71 (yield 71%) is obtained.

[0277] Example 72

[0278] The narrow emission compound based on spirobifluorene in this example has the structural formula of the above (72).

[0279] The difference between this example and Example 51 is that 2,6-difluoroaniline in step (1) of the preparation method is replaced with an equivalent amount of (4-chloro-2-methylphenyl)(methyl)sulfane, and other raw materials and steps are the same as those in Example 51. Finally, compound 72 (yield 73%) is obtained.

[0280] Example 73

[0281] The narrow emission compound based on spirobifluorene in this example has the structural formula of the above (73).

[0282] The difference between this example and Example 51 is that 2,6-difluoroaniline in step (1) of the preparation method is replaced with an equivalent amount of 3-chloro-2-methylsulfinylaniline, and other raw materials and steps are the same as those in Example 51. Finally, compound 73 (yield 86%) is obtained.

[0283] Example 74

[0284] The narrow emission compound based on spirobifluorene in this example has the structural formula of the above (74).

[0285] The difference between this example and Example 51 is that 2,6-difluoroaniline in step (1) of the preparation method is replaced with an equivalent amount of 3-aminobiphenyl, and other raw materials and steps are the same as those in Example 51, and finally Compound 74 (yield 88%) is obtained.

[0286] Example 75

[0287] The narrow-emission compound based on spirobifluorene in this example has the structural formula of the above (75).

[0288] The difference between this example and Example 51 is that 2,6-difluoroaniline in step (1) of the preparation method is replaced with an equivalent amount of [1,1':3',1''-terphenyl]-5'-amine, and other raw materials and steps are the same as those in Example 51, and finally Compound 75 (yield 89%) is obtained.

[0289] Example 76

[0290] The narrow-emission compound based on spirobifluorene in this example has the structural formula of the above (76).

[0291] The preparation method of the above compound includes the following steps:

[0292] (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 overnight at 110 °C; the cooled mixture was filtered through diatomaceous earth 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%);

[0293] (2) - (3) are the same as (2) - (3) in Example 1, and finally Compound 76 (yield 81%) is obtained.

[0294] Example 77

[0295] The narrow-emission compound based on spirobifluorene in this example has the structural formula of the above (77).

[0296] The difference between this example and Example 76 is that 2,6-difluoroaniline in step (1) of the preparation method is replaced with an equivalent amount of o-cyanoaniline, and other raw materials and steps are the same as those in Example 76, and finally Compound 77 (yield 77%) is obtained.

[0297] Example 78

[0298] The narrow emission compound based on spirobifluorene of this embodiment has the structural formula of the above (78).

[0299] The difference between this embodiment and Embodiment 76 is that 2,6-difluoroaniline in the first step of the preparation method is replaced with an equivalent amount of 4-cyanoaniline, and other raw materials and steps are the same as those in Embodiment 76, and finally Compound 78 is obtained (yield 81%).

[0300] Embodiment 79

[0301] The narrow emission compound based on spirobifluorene of this embodiment has the structural formula of the above (79).

[0302] The difference between this embodiment and Embodiment 76 is that 2,6-difluoroaniline in the first step of the preparation method is replaced with an equivalent amount of 2-aminoisophthalonitrile, and other raw materials and steps are the same as those in Embodiment 76, and finally Compound 79 is obtained (yield 83%).

[0303] Embodiment 80

[0304] The narrow emission compound based on spirobifluorene of this embodiment has the structural formula of the above (80).

[0305] The difference between this embodiment and Embodiment 76 is that 2,6-difluoroaniline in the first step of the preparation method is replaced with an equivalent amount of 3-aminophthalonitrile, and other raw materials and steps are the same as those in Embodiment 76, and finally Compound 80 is obtained (yield 86%).

[0306] Embodiment 81

[0307] The narrow emission compound based on spirobifluorene of this embodiment has the structural formula of the above (81).

[0308] The difference between this embodiment and Embodiment 76 is that 2,6-difluoroaniline in the first step of the preparation method is replaced with an equivalent amount of 4-aminoisophthalonitrile, and other raw materials and steps are the same as those in Embodiment 76, and finally Compound 81 is obtained (yield 81%).

[0309] Embodiment 82

[0310] The narrow emission compound based on spirobifluorene of this embodiment has the structural formula of the above (82).

[0311] The difference between this embodiment and Embodiment 76 is that 2,6-difluoroaniline in the first step of the preparation method is replaced with an equivalent amount of 5-aminoterephthalonitrile, and other raw materials and steps are the same as those in Embodiment 76, and finally Compound 82 is obtained (yield 83%).

[0312] Embodiment 83

[0313] The narrow emission compound based on spirobifluorene of this embodiment has the structural formula of the above (83).

[0314] The difference between this embodiment and Embodiment 76 is that 2,6-difluoroaniline in the first step of the preparation method is replaced with an equivalent amount of 2-fluoroaniline, and other raw materials and steps are the same as those in Embodiment 76, and finally Compound 83 is obtained (yield 77%).

[0315] Embodiment 84

[0316] The narrow emission compound based on spirobifluorene of this embodiment has the structural formula of the above (84).

[0317] The difference between this embodiment and Embodiment 76 is that 2,6-difluoroaniline in the first step of the preparation method is replaced with an equivalent amount of 3-fluoroaniline, and other raw materials and steps are the same as those in Embodiment 76, and finally Compound 84 is obtained (yield 79%).

[0318] Embodiment 85

[0319] The narrow emission compound based on spirobifluorene of this embodiment has the structural formula of the above (85).

[0320] The difference between this embodiment and Embodiment 76 is that 2,6-difluoroaniline in the first step of the preparation method is replaced with an equivalent amount of 4-fluoroaniline, and other raw materials and steps are the same as those in Embodiment 76, and finally Compound 85 is obtained (yield 84%).

[0321] Embodiment 86

[0322] The narrow emission compound based on spirobifluorene of this embodiment has the structural formula of the above (86).

[0323] The difference between this embodiment and Embodiment 76 is that 2,6-difluoroaniline in the first step of the preparation method is replaced with an equivalent amount of methylamine, and other raw materials and steps are the same as those in Embodiment 76, and finally Compound 86 is obtained (yield 84%).

[0324] Embodiment 87

[0325] The narrow emission compound based on spirobifluorene of this embodiment has the structural formula of the above (87).

[0326] The difference between this embodiment and Embodiment 76 is that 2,6-difluoroaniline in the first step of the preparation method is replaced with an equivalent amount of 2,3-difluoroaniline, and other raw materials and steps are the same as those in Embodiment 76, and finally Compound 87 is obtained (yield 76%).

[0327] Embodiment 88

[0328] The narrow emission compound based on spirobifluorene of this embodiment has the structural formula of the above (88).

[0329] The difference between this example and Example 76 is that 2,6-difluoroaniline in step (1) of the preparation method is replaced with an equivalent amount of 2,4-difluoroaniline, and other raw materials and steps are the same as those in Example 76. Finally, compound 88 (yield 73%) is obtained.

[0330] Example 89

[0331] The narrow emission compound based on spirobifluorene in this example has the structural formula of the above (89).

[0332] The difference between this example and Example 76 is that 2,6-difluoroaniline in step (1) of the preparation method is replaced with an equivalent amount of 3,5-difluoroaniline, and other raw materials and steps are the same as those in Example 76. Finally, compound 89 (yield 79%) is obtained.

[0333] Example 90

[0334] The narrow emission compound based on spirobifluorene in this example has the structural formula of the above (90).

[0335] The difference between this example and Example 76 is that 2,6-difluoroaniline in step (1) of the preparation method is replaced with an equivalent amount of o-chloroaniline, and other raw materials and steps are the same as those in Example 76. Finally, compound 90 (yield 86%) is obtained.

[0336] Example 91

[0337] The narrow emission compound based on spirobifluorene in this example has the structural formula of the above (91).

[0338] The difference between this example and Example 76 is that 2,6-difluoroaniline in step (1) of the preparation method is replaced with an equivalent amount of 3-chloroaniline, and other raw materials and steps are the same as those in Example 76. Finally, compound 91 (yield 86%) is obtained.

[0339] Example 92

[0340] The narrow emission compound based on spirobifluorene in this example has the structural formula of the above (92).

[0341] The difference between this example and Example 76 is that 2,6-difluoroaniline in step (1) of the preparation method is replaced with an equivalent amount of 4-chloroaniline, and other raw materials and steps are the same as those in Example 76. Finally, compound 92 (yield 81%) is obtained.

[0342] Example 93

[0343] The narrow emission compound based on spirobifluorene in this example has the structural formula of the above (93).

[0344] The difference between this example and Example 76 is that 2,6-difluoroaniline in step (1) of the preparation method is replaced with an equivalent amount of 2,6-dichloroaniline, and other raw materials and steps are the same as those in Example 76, and finally Compound 93 (yield 73%) is obtained.

[0345] Example 94

[0346] The narrow emission compound based on spirobifluorene in this example has the structural formula of the above (94).

[0347] The difference between this example and Example 76 is that 2,6-difluoroaniline in step (1) of the preparation method is replaced with an equivalent amount of 2,3-dichloroaniline, and other raw materials and steps are the same as those in Example 76, and finally Compound 94 (yield 76%) is obtained.

[0348] Example 95

[0349] The narrow emission compound based on spirobifluorene in this example has the structural formula of the above (95).

[0350] The difference between this example and Example 76 is that 2,6-difluoroaniline in step (1) of the preparation method is replaced with an equivalent amount of 2,4-dichloroaniline, and other raw materials and steps are the same as those in Example 76, and finally Compound 95 (yield 79%) is obtained.

[0351] Example 96

[0352] The narrow emission compound based on spirobifluorene in this example has the structural formula of the above (96).

[0353] The difference between this example and Example 76 is that 2,6-difluoroaniline in step (1) of the preparation method is replaced with an equivalent amount of 3,5-dichloroaniline, and other raw materials and steps are the same as those in Example 76, and finally Compound 96 (yield 76%) is obtained.

[0354] Example 97

[0355] The narrow emission compound based on spirobifluorene in this example has the structural formula of the above (97).

[0356] The difference between this example and Example 76 is that 2,6-difluoroaniline in step (1) of the preparation method is replaced with an equivalent amount of (4-chloro-2-methylphenyl)(methyl) sulfane, and other raw materials and steps are the same as those in Example 76, and finally Compound 97 (yield 86%) is obtained.

[0357] Example 98

[0358] The narrow emission compound based on spirobifluorene in this example has the structural formula of the above (98).

[0359] The difference between this example and Example 76 is that 2,6-difluoroaniline in step (1) of the preparation method is replaced with an equivalent amount of 3-chloro-2-methylsulfinylaniline, and other raw materials and steps are the same as those in Example 76, and finally compound 98 (yield 82%) is obtained.

[0360] Example 99

[0361] The narrow emission compound based on spirobifluorene in this example has the structural formula of the above (99).

[0362] The difference between this example and Example 76 is that 2,6-difluoroaniline in step (1) of the preparation method is replaced with an equivalent amount of 3-aminobiphenyl, and other raw materials and steps are the same as those in Example 76, and finally compound 99 (yield 89%) is obtained.

[0363] Example 100

[0364] The narrow emission compound based on spirobifluorene in this example has the structural formula of the above (100).

[0365] The difference between this example and Example 76 is that 2,6-difluoroaniline in step (1) of the preparation method is replaced with an equivalent amount of [1,1':3',1''-terphenyl]-5'-amine, and other raw materials and steps are the same as those in Example 76, and finally compound 100 (yield 83%) is obtained.

[0366] The compounds of Examples 1, 26, 51, and 76 were subjected to relevant solubility and thermodynamic stability tests, and the specific test results are shown in Figures 1 to 2 .

[0367] Figure 1 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 is the thermogravimetric analysis curve of the compounds of Examples 1, 26, 51, and 76 of the present invention. It can be seen from Figures 1 to 2 that through test 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.

[0368] Organic light-emitting devices were fabricated using the spirobifluorene-based narrow emission compounds of Examples 1, 26, 51, and 76 and conventional spiro non-MR-TADF compounds. The electroluminescent devices had the following binary sensitized OLED structure: glass substrate / indium tin oxide / TAPC (30 nm) / mCP (10 nm) / X wt% compound (X = 2 / 3 / 5 / 7): X' wt% DOBNA-oAr (30 nm, X + X' = 100) / PPF (10 nm) / TmPyPB (40 nm) / lithium fluoride (1 nm) / aluminum (150 nm). Among them, indium tin oxide is the anode, TAPC is the hole injection layer, mCP is the hole transport layer, X wt% compound 1 (X = 2 / 3 / 5 / 7): X' wt% DOBNA-oAr and PPF are the light-emitting layers, TmPyPB is the electron transport layer, lithium fluoride is the electron injection layer, and aluminum is the cathode.

[0369] The structural formulas of TAPC, mCP, DOBNA-oAr, PPF, and TmPyPB are as follows:

[0370] ;

[0371] The structural formula of the conventional spiro non-MR-TADF compound is as follows:

[0372] .

[0373] The preparation method of the organic light-emitting device is as follows: The transparent conductive indium tin oxide glass substrate was ultrasonically cleaned with a micron-level semiconductor special detergent, deionized water, acetone, and isopropanol for 15 min in sequence to remove the dirt on the substrate surface, and then placed in an oven at 80 °C for drying for later use; the dried ITO substrate was treated with oxygen-Plasma for 5 min to further remove the organic pollutants attached to the surface; finally, TAPC, mCP, the compound, DOBNA-oAr, PPF, TmPyPB, lithium fluoride, and aluminum were thermally deposited in sequence by vacuum thermal evaporation to obtain the organic light-emitting device, and relevant performance tests were carried out. The specific test results are shown in Figures 3 to 4 and Table 1.

[0374] Figure 3 are the current density-voltage-brightness curves of the organic light-emitting devices fabricated with the compounds of Examples 1, 26, 51, and 76 of the present invention. Figure 4 are the external quantum efficiency-brightness curves and the emission spectra of the organic light-emitting devices fabricated with the compounds of Examples 1, 26, 51, and 76 of the present invention. It can be seen from Figures 3 to 4 that after fabricating the spirobifluorene-based narrow emission compounds prepared in the present invention into organic light-emitting devices, they exhibit excellent properties of high luminous efficiency and narrow emission spectra.

[0375] Table 1 External Quantum Efficiency Data Sheet of Electroluminescent Devices

[0376] 。

[0377] As can be seen from Table 1, the external quantum efficiency of the electroluminescent device prepared using a conventional spiro-based non-MR-TADF (whose structural formula is as follows) is 10.59%, while the maximum external quantum efficiency of the organic electroluminescent device prepared from the spirobifluorene-based narrow emission compound of the present invention can reach 35.5%, which is sufficient to prove its high external quantum efficiency.

[0378] All aspects, embodiments, and features of the present invention should be considered illustrative in all respects and not limiting to the present invention. The scope of the present invention is only defined by the claims. Without departing from the spirit and scope of the claimed invention, those skilled in the art will understand other embodiments, modifications, and uses.

[0379] In the preparation method of the present invention, the order of each step is not limited to the listed order. For those of ordinary skill in the art, without creative efforts, the sequential changes of each step are also within the protection scope of the present invention. In addition, two or more steps or actions can be carried out simultaneously.

[0380] Finally, it should be noted that the specific embodiments described herein are only examples of the present invention and do not limit the implementation manners of the present invention. Those skilled in the technical field of the present invention can make various modifications or supplements to the described specific embodiments or use similar ways to replace them. It is not necessary and impossible to list all implementation manners here. And these obvious changes or variations derived from the essential spirit of the present invention still belong to the protection scope of the present invention. Interpreting them as any additional limitations 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 structures: ； Wherein, the structures of R and R' are shown in Formula I: 。 2. The method for preparing a narrow emission compound based on spirobifluorene according to claim 1, 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; mixing the intermediate 2, a boron halide and an organic solvent for a third reaction to obtain the spirobifluorene-based narrow emission compound; In the first reaction, the spirobifluorene is one 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 is 2,6-difluoroaniline; The catalyst in the first reaction and / or the second reaction is a palladium catalyst, and the palladium catalyst is one or more of Pd2(dba)3, Pd(OAc)2, PdCl2(dppf), and Pd(PPh3)4; The electron-rich ligand in the first reaction and / or the second reaction is one or more of tBu3PHBF4, Xantphos, BINAP, P(t-Bu)3, and RuPhos; The base in the first reaction and / or the second reaction is one or more of tBuONa, Cs2CO3, tBuOK, Et3N, DIPEA, K2CO3, Na2CO3, K3PO4, NaOH, and KOH; The boron halide in the third reaction is one or more of boron bromide, boron chloride and boron iodide.

3. The preparation method according to claim 2, 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.

4. The preparation method according to claim 2, 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.

5. An electroluminescent device, characterized in that: The structure of the electroluminescent device comprises an organic functional layer unit, and the organic functional layer unit comprises the spirobifluorene-based narrow emission compound as claimed in claim 1.

6. An electroluminescent device according to claim 5, characterized in that: The electroluminescent device comprises the following structure: an ITO substrate, and 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.

7. The method for preparing an electroluminescent device according to claim 6, characterized in that: The preparation method comprises the following steps: forming 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.

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