阅读说明：本技术 一种基于对称芳香胺结构的有机电致发光化合物 (Organic electroluminescent compound based on symmetric aromatic amine structure ) 是由 钱超 许军 于 2019-09-20 设计创作，主要内容包括：本发明公开了一种基于对称芳香胺结构的有机电致发光化合物,所述有机电致发光化合物的结构式如下通式(Ⅰ)所示：本发明有机电致发光化合物具有较高的玻璃化温度,热稳定性好,而且折射率高,应用于有机电致发光器件中,在相同电流密度下,发光效率都得到了一定提升,器件的启动电压下降,功耗相对降低,使用寿命相应提高。(The invention discloses an organic electroluminescent compound based on a symmetrical aromatic amine structure, which has a structural formula shown as the following general formula (I): the organic electroluminescent compound has higher glass transition temperature, good thermal stability and high refractive index, is applied to organic electroluminescent devices, and has the advantages of improving the luminous efficiency to a certain extent, reducing the starting voltage of the devices, relatively reducing the power consumption and correspondingly improving the service life under the condition of the same current density.)

1. An organic electroluminescent compound based on a symmetrical aromatic amine structure, which is characterized in that the structural formula of the organic electroluminescent compound is shown as the following general formula (I):

wherein, L is any one of substituted or unsubstituted phenylene, substituted or unsubstituted fluorenylene, substituted or unsubstituted dibenzothiophene, substituted or unsubstituted oxyfluorene, substituted or unsubstituted spirobifluorene, substituted or unsubstituted N-phenylcarbazolyl, substituted or unsubstituted 9, 9-diphenylfluorene and substituted or unsubstituted 9, 9-dimethylfluorene;

r1, R2, R3 and R4 are each independently hydrogen, general formula (II) and general formula (III), and R1, R2, R3 and R4 are not simultaneously hydrogen:

wherein, R5 and R6 are respectively any one of hydrogen, deuterium, methyl and phenyl;

r7, R8, R9, R10, R11 and R12 are respectively and independently hydrogen, deuterium, C1-C3 straight-chain or branched-chain alkyl;

x1 is N or CH, X2 is O or S, Y1, Y2 are each independently N or CH, and at least one of Y1, Y2 is N;

ar is substituted or unsubstituted C6-C18 aryl;

m is 0 or 1.

2. The organic electroluminescent compound according to claim 1, wherein R1 and R2 are the same, and R3 and R4 are the same.

3. The organic electroluminescent compound according to claim 1, wherein L is selected from the group consisting of

Any one of them.

4. The organic electroluminescent compound according to claim 1, wherein R1, R2, R3 and R4 are each independently hydrogen,

5. The organic electroluminescent compound according to claim 1, wherein Ar is any one of a substituted or unsubstituted phenyl group, a substituted or unsubstituted naphthyl group, and a substituted or unsubstituted phenanthryl group.

6. The organic electroluminescent compound according to any one of claims 1 to 5, wherein the organic electroluminescent compound is one of the compounds of the following structural formula:

7. use of an organic electroluminescent compound as claimed in any of claims 1 to 6 for the preparation of an organic electroluminescent device.

8. An organic electroluminescent device, characterized in that the organic electroluminescent device comprises: a structure in which an anode, a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, an electron injection layer, and a cathode are sequentially stacked; the surface of the cathode is also provided with a covering layer; the cover layer contains at least one organic electroluminescent compound as claimed in any of claims 1 to 6.

9. An organic electroluminescent display device characterized by comprising the organic electroluminescent device according to claim 8.

10. An organic electroluminescent lighting device characterized by comprising the organic electroluminescent element as claimed in claim 8.

Technical Field

The invention relates to the field of organic electroluminescent materials, in particular to an organic electroluminescent compound based on a symmetrical aromatic amine structure.

Background

The related research of organic electroluminescent devices began in the 60's of the 19 th century, and OLEDs were not developed vigorously until the end of the 80's. The OLED has the advantages of all solid state, low-voltage driving, active light emitting, quick response, wide viewing angle, large light emitting area, light emitting wavelength covering the whole visible light region, rich colors and the like, has great advantages in the field of realizing full-color large-area display, and becomes a flat panel display device with great prospect. The luminance of an organic electroluminescent device is proportional to the product of the concentration of holes and electrons and the recombination probability of excitons, and in order to obtain high luminous efficiency, it is required that not only the holes and the electrons can be effectively injected, transported and recombined, but also the holes and the electrons are required to be injected in balance. Therefore, in the organic electroluminescent device, energy band matching between organic layers and between the organic layers and both electrodes is very important for composite light emission of the device.

Because a great difference exists between the external quantum efficiency and the internal quantum efficiency of the OLED, the development of the OLED is greatly restricted, and therefore, how to improve the light extraction efficiency of the OLED also becomes a hot point of research. The total reflection can occur at the interface of the ITO film and the glass substrate and the interface of the glass substrate and the air, the light emitted to the front external space of the OLED device accounts for about 20% of the total EL of the organic material film, and the rest about 80% of the light is mainly limited in the organic material film, the ITO film and the glass substrate in a guided wave mode, so that the development and the application of the OLED are seriously restricted, the total reflection effect in the OLED device is reduced, the proportion of the light coupled to the front external space of the device is improved, and the performance of the device is further improved, thereby playing a wide role in people.

At present, an important method for improving the light extraction efficiency of the OLED is to add a covering layer on the light extraction surface, and the CPL material commonly used is a hole layer material or an electron layer material, such as CBP, Alq3, TPBi and other materials, but the refractive index of the CPL material is only 1.8-1.9, which is slightly higher than that of a common OLED organic material. Therefore, the development of high-performance CPL layer materials has become a hot research point in the OLED industry.

Disclosure of Invention

The invention aims to provide an organic electroluminescent compound based on a symmetrical aromatic amine structure,

in order to achieve the purpose of the invention, the technical scheme adopted by the invention is as follows:

an organic electroluminescent compound based on a symmetrical aromatic amine structure, wherein the structural formula of the organic electroluminescent compound is shown as the following general formula (I):

wherein, L is any one of substituted or unsubstituted phenylene, substituted or unsubstituted fluorenylene, substituted or unsubstituted dibenzothiophene, substituted or unsubstituted oxyfluorene, substituted or unsubstituted spirobifluorene, substituted or unsubstituted N-phenylcarbazolyl, substituted or unsubstituted 9, 9-diphenylfluorene and substituted or unsubstituted 9, 9-dimethylfluorene;

r1, R2, R3 and R4 are each independently hydrogen, general formula (II) and general formula (III), and R1, R2, R3 and R4 are not simultaneously hydrogen:

wherein, R5 and R6 are respectively any one of hydrogen, deuterium, methyl and phenyl;

r7, R8, R9, R10, R11 and R12 are respectively and independently hydrogen, deuterium, C1-C3 straight-chain or branched-chain alkyl;

x1 is N or CH, X2 is O or S, Y1, Y2 are each independently N or CH, and at least one of Y1, Y2 is N;

ar is substituted or unsubstituted C6-C18 aryl;

m is 0 or 1.

Further, R1 and R2 are the same, and R3 and R4 are the same.

Further, L is selected from

Any one of them.

Further, R1, R2, R3 and R4 are each independently hydrogen,

Further, Ar is any one of a substituted or unsubstituted phenyl group, a substituted or unsubstituted naphthyl group, and a substituted or unsubstituted phenanthryl group.

Further, the organic electroluminescent compound is one of the following structural formula compounds:

the invention also discloses application of the organic electroluminescent compound in preparing organic electroluminescent devices.

Further, the present invention also provides an organic electroluminescent device comprising: a structure in which an anode, a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, an electron injection layer, and a cathode are sequentially stacked; the surface of the cathode is also provided with a covering layer; the cover layer contains at least one of the above organic electroluminescent compounds.

Further, the invention also provides an organic electroluminescent display device which contains the organic electroluminescent device.

Further, the invention also provides an organic electroluminescent lighting device which contains the organic electroluminescent device.

The invention has the beneficial effects that:

the organic electroluminescent compound designed by the invention has a higher NK value as a CPL material, and the high NK value can effectively improve the light-emitting rate of an organic electroluminescent device, so that the luminous efficiency of the organic electroluminescent device is greatly improved. Meanwhile, the molecular weight of the material molecule designed by the invention is relatively high, so that the material molecule has higher Tg (glass transition temperature), the application range and the application of the material are expanded, the stability of an organic electroluminescent device can be improved, and the service life of the organic electroluminescent device is prolonged.

Drawings

Fig. 1 is a schematic structural diagram of an organic electroluminescent device provided by the present invention;

the reference numbers in the figures represent respectively:

1-covering layer, 2-cathode, 3-electron injection layer, 4-electron transport layer, 5-luminescent layer, 6-hole transport layer, 7-hole injection layer and 8-anode.

Detailed Description

The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially.

Example 1:

the synthesis method of the organic electroluminescent compound (1) is as follows:

under the protection of nitrogen, adding compound 1-a (benzidine) (1eq, 10.0g, 184.1g/mol, 54.32mmol), compound 1-b (bromobenzene) (2eq, 16.94g, 155.96g/mol, 108.64mmol), sodium tert-butoxide (2.2eq, 11.48g, 96.1g/mol, 119.5mmol), tris (dibenzylideneacetone) dipalladium (0.05eq, 2.49g, 915g/mol, 2.72mmol), tri-tert-butylphosphine (0.05eq, 0.55g, 202.32g/mol, 2.72mol) and toluene (100ml) into a reaction bottle, heating to reflux reaction for 5h after the reaction is finished, adding 100ml of water after the reaction is finished, stirring for 15min to obtain a filtrate, filtering the filtrate through diatomite, separating to obtain an organic phase, drying the organic phase, performing anhydrous column chromatography, purifying by magnesium sulfate, purifying by N- [ 1-539-36-phenyl- [ 1-36-N' -yl ] after the reaction is finished, 1' -biphenyl]-4,4' -diamine) (14.64g, yield 80.2%), ms (ei): 336 (M)⁺)。

Under the protection of nitrogen, compound 1-c (1eq, 14.0g, 336.16g/mol, 41.65mmol), compound 1-d (2- (4-bromophenyl) -5, 5-dimethyl-5H-fluoroeno [2, 3-d)]oxazole) (2eq, 32.4g, 389g/mol, 83.3mmol), sodium tert-butoxide (2.2eq, 8.8g, 96.1g/mol, 91.62mmol), tris (dibenzylideneacetone) dipalladium (0.05eq, 1.91g, 915g/mol, 2.08mmol), tri-tert-butylphosphine (0.05eq, 0.42g, 202.32g/mol, 2.08mol) and toluene (140ml) are added into a reaction bottle, after the addition, the temperature is raised to reflux reaction for 5H, after the reaction is finished, the temperature is reduced to room temperature, 140ml of water is added, stirring is carried out for 15min, filtrate is obtained, after filtration through kieselguhr, liquid separation is carried out to obtain an organic phase, the organic phase is dried through anhydrous magnesium sulfate and then is dried, and after column chromatography purification, the organic electroluminescent compound (1) (N4, N4' -bis (4- (5, 5-dimethyl-5H-fluoroeno [2,3-d ]) is obtained]oxazol-2-yl)phenyl)-N4,N4'-diphenyl-[1,1'-biphenyl]-4,4' -diamine) (26.82g, yield 67.5%), ms (ei): 954 (M)⁺)。

Example 2:

under the protection of nitrogen, compound 2-a (1eq, 10.0g, 336.16g/mol, 29.75mmol), compound 2-b (2- (4-bromophenyl) -5,5, 9-trimetyl-5H-fluoroeno [2, 3-d)]oxazole) (2eq, 23.98g, 403.06g/mol, 59.5mmol), sodium tert-butoxide (2.2eq, 6.29g, 96.1g/mol, 65.45mmol), tris (dibenzylideneacetone) dipalladium (0.05eq, 1.36g, 915g/mol, 1.49mmol), tri-tert-butylphosphine (0.05eq, 0.3g, 202.32g/mol, 1.49mol), toluene (100ml) were added to the reaction flask, heating to reflux reaction for 5H after the addition is finished, cooling to room temperature after the reaction is finished, adding 100ml of water, stirring for 15min, filtering to obtain a filtrate, filtering the filtrate through diatomite, separating liquid to obtain an organic phase, drying the organic phase through anhydrous magnesium sulfate, spin-drying, and purifying by column chromatography to obtain the organic electroluminescent compound (4) (N4, N4'-diphenyl-N4, N4' -bis (4- (5,5, 9-trimethy-5H-fluoroeno [2,3-d ]).]oxazol-2-yl)phenyl)-[1,1'-biphenyl]-4,4' -diamine) (19.55g, yield 66.9%), ms (ei): 982 (M)⁺)。

Example 3:

under the protection of nitrogen, the nitrogen gas is used for protecting the reaction vessel,mixing compound 3-a (benzodiine) (1eq, 10.0g, 184.10g/mol, 54.32mmol), compound 3-b (2- (4-bromophenyl) -5, 5-dimethyl-5H-fluoroeno [2, 3-d)]Adding oxazole) (4eq, 84.53g, 389.04g/mol, 217.28mmol), sodium tert-butoxide (4.4eq, 22.97g, 96.1g/mol, 239mmol), tris (dibenzylideneacetone) dipalladium (0.05eq, 2.49g, 915g/mol, 2.72mmol), tri-tert-butylphosphine (0.05eq, 0.55g, 202.32g/mol, 2.72mol) and toluene (100ml) into a reaction bottle, heating to reflux reaction for 5H after the addition is finished, cooling to room temperature after the reaction is finished, adding 100ml of water, stirring for 15min, filtering to obtain a filtrate, filtering the filtrate through kieselguhr to separate liquid to obtain an organic phase, drying the organic phase through anhydrous magnesium sulfate, and carrying out column chromatography purification to obtain the organic electroluminescent compound (9) (N4, N4' -bis (4- (5, 5-dimethyl-5H-fluorono) [2,3-d ] column chromatography]oxazol-2-yl)phenyl)-N4,N4'-diphenyl-[1,1'-biphenyl]-4,4' -diamine) (47.2g, yield 61.2%), ms (ei): 1420 (M)⁺)。

Example 4:

the synthesis method of the organic electroluminescent compound (17) is as follows:

under the protection of nitrogen, compound 4-a ([1,1':4', 1' -terphenyl)]-4,4 "-diamine) (1eq, 10.0g, 260.13g/mol, 38.44mmol), compound 1-b (bromobenzene) (2eq, 11.99g, 155.96g/mol, 76.88mmol), sodium tert-butoxide (2.2eq, 8.13g, 96.1g/mol, 84.57mmol), tris (dibenzylideneacetone) dipalladium (0.05eq, 1.76g, 915g/mol, 1.92mmol), tri-tert-butylphosphine (0.05eq, 0.39g, 202.32g/mol, 1.92mol), toluene (100ml) were added to a reaction flask, after the addition was complete, the temperature was raised to reflux for 5h, after the reaction was cooled to room temperature, 100ml of water was added, after stirring for 15min, the filtrate was filtered through celite, the organic phase was separated by rotary liquid separation, the organic phase was dried with anhydrous magnesium sulfate, purified by column chromatography, and after the reaction was completeTo obtain the compound 4-c (N4, N4'-diphenyl- [1,1':4', 1' -terphenyl)]-4,4 "-diamine) (13.24g, yield 83.6%), ms (ei): 412 (M)⁺)。

Under the protection of nitrogen, compound 4-c (1eq, 13.0g, 412.19g/mol, 31.54mmol), compound 4-d (2- (4-bromophenyl) -5, 5-dimethyl-5H-fluoroeno [2, 3-d)]Adding oxazole) (2eq, 24.54g, 389.04g/mol, 63.08mmol), sodium tert-butoxide (2.2eq, 6.67g, 96.1g/mol, 69.39mmol), tris (dibenzylideneacetone) dipalladium (0.05eq, 1.44g, 915g/mol, 1.57mmol), tri-tert-butylphosphine (0.05eq, 0.32g, 202.32g/mol, 1.57mol) and toluene (130ml) into a reaction bottle, heating to reflux reaction for 5H after the addition is finished, cooling to room temperature after the reaction is finished, adding 130ml of water, stirring for 15min, filtering to obtain a filtrate, separating the filtrate by diatomite to obtain an organic phase, drying the organic phase by anhydrous magnesium sulfate, spin-drying, and purifying to obtain the organic electroluminescent compound (17) (N4, N4' -bis (4- (5, 5-dimethyl-5H-fluorono) [2,3-d ]]oxazol-2-yl)phenyl)-N4,N4”-diphenyl-[1,1':4',1”-terphenyl]-4,4 "-diamine) (22.45g, 69.1% yield), ms (ei): 1030 (M)⁺)。

Example 5:

the synthesis method of the organic electroluminescent compound (38) is as follows:

under the protection of nitrogen, compound 5-a (4,4' - (dibenzo [ b, d)]furan-3,7-diyl) dianiline) (1eq, 10.0g, 350.14g/mol, 28.56mmol), compound 5-b (bromobenzene) (2eq, 8.91g, 155.96g/mol, 57.12mmol), sodium tert-butoxide (2.2eq, 6.04g, 96.1g/mol, 62.83mmol), tris (dibenzylideneacetone)) Dipalladium (0.05eq, 1.31g, 915g/mol, 1.43mmol), tri-tert-butylphosphine (0.05eq, 0.29g, 202.32g/mol, 1.43mol) and toluene (100ml) are added into a reaction bottle, after the addition of materials, the temperature is raised to reflux reaction for 5h, after the reaction is finished, the temperature is reduced to room temperature, 100ml of water is added, the mixture is stirred for 15min and filtered to obtain filtrate, the filtrate is filtered by diatomite and separated into organic phases, the organic phases are dried by anhydrous magnesium sulfate and then spin-dried, and the compounds 5-c (4,4' - (dibezo [ b, d ] are obtained after column chromatography purification]furan-3,7-diyl) bis (N-phenyleneiline) (10.74g, 74.9% yield), ms (ei): 502 (M)⁺)。

Under the protection of nitrogen, compound 5-c (1eq, 10.0g, 502.2g/mol, 19.91mmol), compound 5-d (2- (4-bromophenyl) -5, 5-dimethyl-5H-fluoroeno [3, 2-b)]furan) (2eq, 15.45g, 388.05g/mol, 39.82mmol), sodium tert-butoxide (2.2eq, 4.21g, 96.1g/mol, 43.81mmol), tris (dibenzylideneacetone) dipalladium (0.05eq, 0.91g, 915g/mol, 1mmol), tri-tert-butylphosphine (0.05eq, 0.2g, 202.32g/mol, 1mol), toluene (100ml) were added to a reaction flask, after the addition, the temperature was raised to reflux reaction for 5h, after the reaction was completed, 100ml water was added to the reaction flask, after the reaction was cooled to room temperature, the reaction solution was stirred for 15min, and then filtered, the filtrate was separated by diatomaceous earth to obtain an organic phase, the organic phase was dried by anhydrous column chromatography and then spin dried, and purified to obtain the organic electroluminescent compound (38) (4,4' - (dibenzo [ b, d)]furan-3,7-diyl)bis(N-(4-(5,5-dimethyl-5H-fluoreno[3,2-b]furan-2-yl) phenyl) -N-phenylaniline) (13.96g, 62.7% yield), ms (ei): 1118 (M)⁺)。

Example 6:

the synthesis method of the organic electroluminescent compound (47) is as follows:

under the protection of nitrogen, compound 6-a (4,4' - (dibenzo [ b, d)]thiophene-3,7-diyl) dianiline) (1eq, 10.0g, 366.12g/mol, 27.31mmol), compound 1-b (bromobenzene) (2eq, 8.52g, 155.96g/mol, 54.63mmol), sodium tert-butoxide (2.2eq, 5.77g, 96.1g/mol, 60.09mmol), tris (dibenzylideneacetone) dipalladium (0.05eq, 1.25g, 915g/mol, 1.37mmol), tri-tert-butylphosphine (0.05eq, 0.28g, 202.32g/mol, 1.37mol), toluene (100ml) were added to a reaction flask, heating to reflux reaction for 5h after the addition is finished, cooling to room temperature after the reaction is finished, adding 100ml of water, stirring for 15min, filtering to obtain a filtrate, filtering the filtrate through diatomite, separating liquid to obtain an organic phase, drying the organic phase through anhydrous magnesium sulfate, spin-drying, and purifying through column chromatography to obtain the compound 6-c (4,4' - (dibenzo [ b, d).]thiophene-3,7-diyl) bis (N-phenyleneiline) (10.36g, 73.2% yield), ms (ei): 518 (M)⁺)。

Under the protection of nitrogen, compound 6-c (1eq, 10.0g, 518.18g/mol, 19.3mmol), compound 6-d (2- (4-bromophenyl) -5, 5-diphenyl-5H-fluoroeno [2, 3-d)]Adding 2eq, 23.66g, 613.07g/mol, 38.59mmol of oxazole), sodium tert-butoxide (2.2eq, 4.08g, 96.1g/mol, 42.46mmol), tris (dibenzylideneacetone) dipalladium (0.05eq, 0.88g, 915g/mol, 0.96mmol), tri-tert-butylphosphine (0.05eq, 0.19g, 202.32g/mol, 0.96mol) and toluene (100ml) into a reaction bottle, heating to reflux reaction for 5h after the addition is finished, cooling to room temperature after the reaction is finished, adding 100ml of water, stirring for 15min, filtering to obtain a filtrate, separating the filtrate by diatomite filtration to obtain an organic phase, drying the organic phase by anhydrous magnesium sulfate, spin-drying, and purifying to obtain the organic electroluminescent compound (47) (4,4' - (dibenzo [ b, d) after the reaction is finished, and the organic electroluminescent compound is obtained by using a solid-liquid chromatography]thiophene-3,7-diyl)bis(N-(4-(5,5-diphenyl-5H-fluoreno[2,3-d]oxazol-2-yl) phenyl) -N-phenylaniline) (16.48g, 61.7% yield), ms (ei): 1384 (M)⁺)。

Example 7:

the synthesis method of the organic electroluminescent compound (53) is as follows:

under the protection of nitrogen, adding compound 7-a (4,4' - (9, 9-dimethyl-9H-fluoroene-2, 7-diyl) dianiline) (1eq, 10.0g, 376.19g/mol, 26.58mmol), compound 1-b (bromobenzene) (2eq, 8.29g, 155.96g/mol, 53.16mmol), sodium tert-butoxide (2.2eq, 5.62g, 96.1g/mol, 58.48mmol), tris (dibenzylideneacetone) dipalladium (0.05eq, 1.22g, 915g/mol, 1.33mmol), tri-tert-butylphosphine (0.05eq, 0.27g, 202.32g/mol, 1.33mol), toluene (100ml) into a reaction bottle, heating to reflux reaction for 5H after finishing charging, cooling to room temperature after reaction, adding 100ml of water, stirring for 15min, filtering the filtrate to obtain an organic phase, filtering the organic phase without water, separating the organic phase by using kieselguhr, after column chromatography purification, compound 6-c (4,4' - (9, 9-dimethyl-9H-fluoroene-2, 7-diyl) bis (N-phenylalaniline)) (10.63g, yield 75.7%), ms (ei): 528 (M)⁺)。

Under the protection of nitrogen, compound 7-c (1eq, 10.0g, 528.26g/mol, 18.93mmol), compound 7-d (2- (4-bromophenyl) -5,5,9, 10-tetramethyl-5H-fluoroeno [2,3-d ] are reacted]Adding oxazole) (2eq, 15.79g, 417.07g/mol, 37.86mmol), sodium tert-butoxide (2.2eq, 4g, 96.1g/mol, 41.65mmol), tris (dibenzylideneacetone) dipalladium (0.05eq, 0.87g, 915g/mol, 0.95mmol), tri-tert-butylphosphine (0.05eq, 0.19g, 202.32g/mol, 0.95mol) and toluene (100ml) into a reaction bottle, heating to reflux reaction for 5h after the addition is finished, cooling to room temperature after the reaction is finished, adding 100ml of water, stirring for 15min, filtering to obtain a filtrate, and carrying out silicon-assisted filtration on the filtrateFiltering the diatomite, separating the solution to obtain an organic phase, drying the organic phase by using anhydrous magnesium sulfate, then spin-drying the organic phase, and purifying the organic phase by column chromatography to obtain an organic electroluminescent compound (53) (4,4' - (9, 9-dimethyl-9H-fluoroene-2, 7-dimethyl) bis (N-phenyl-N- (4- (5,5,9, 10-tetramethyl-5H-fluoroeno [2, 3-d))]oxazol-2-yl) phenyl) aniline) (13.93g, 61.2% yield), ms (ei): 1202 (M)⁺)。

Example 8:

the synthesis method of the organic electroluminescent compound (66) is as follows:

under the protection of nitrogen, adding compound 8-a (4,4' - (9-phenyl-9H-carbazole-2,7-diyl) dianiline) (1eq, 10.0g, 425.19g/mol, 23.51mmol), compound 8-b (bromobrenzene) (2eq, 7.34g, 155.96g/mol, 47.04mmol), sodium tert-butoxide (2.2eq, 4.97g, 96.1g/mol, 51.74mmol), tris (dibenzylideneacetone) dipalladium (0.05eq, 1.08g, 915g/mol, 1.18mmol), tri-tert-butylphosphine (0.05eq, 0.24g, 202.32g/mol, 1.18mol), toluene (100ml) into a reaction bottle, heating to reflux reaction for 5H after finishing the addition, cooling to room temperature after the reaction, adding 100ml of water, stirring for 15min, filtering the filtrate, drying the organic phase with diatomite to obtain an organic phase without water, after column chromatography purification, compound 8-c (4,4' - (9-phenyl-9H-carbazole-2,7-diyl) bis (N-phenylalaniline)) (9.96g, yield 73.4%), ms (ei): 577 (M)⁺)。

Under the protection of nitrogen, compound 8-c (1eq, 9g, 577.25g/mol, 15.59mmol), compound 8-d (2- (4-bromophenyl) -5H-fluoroeno [2,3-d ] are reacted]oxazole)(2eq，11.26g，361g/31.18mmol of sodium tert-butoxide (2.2eq, 3.29g, 96.1g/mol, 34.3mmol), tris (dibenzylideneacetone) dipalladium (0.05eq, 0.71g, 915g/mol, 0.78mmol), tri-tert-butylphosphine (0.05eq, 0.16g, 202.32g/mol, 0.78mol) and toluene (100ml) are added into a reaction bottle, after the addition, the temperature is raised to reflux reaction for 5H, after the reaction is finished, 100ml of water is added into the reaction bottle to stir for 15min, filtrate is obtained after the reaction is finished, the filtrate is filtered by diatomite and separated to obtain an organic phase, the organic phase is dried by anhydrous magnesium sulfate and dried in a rotary manner, and after column chromatography purification, the organic electroluminescent compound (66) (4,4' - (9-phenyl-9H-carbozole-2, 7-diyl) bis (N- (4- (5H-fluorono [2,3-d ] is obtained]oxazol-2-yl) phenyl) -N-phenylaniline) (10.41g, 58.6% yield), ms (ei): 1139 (M)⁺)。

Example 9:

the synthesis method of the organic electroluminescent compound (79) is as follows:

under the protection of nitrogen, compound 9-a (4,4'- (9,9' -spirobi [ fluoroene ])]-2,7-diyl) dianiline) (1eq, 10.0g, 498.21g/mol, 20.07mmol), compound 9-b (bromobrenzene) (2eq, 6.26g, 155.96g/mol, 40.14mmol), sodium tert-butoxide (2.2eq, 4.24g, 96.1g/mol, 44.15mmol), tris (dibenzylideneacetone) dipalladium (0.05eq, 0.92g, 915g/mol, 1mmol), tri-tert-butylphosphine (0.05eq, 0.2g, 202.32g/mol, 1mol), toluene (100ml) were added to a reaction flask, heating to reflux reaction for 5h after the addition is finished, cooling to room temperature after the reaction is finished, adding 100ml of water, stirring for 15min, filtering to obtain a filtrate, filtering the filtrate through diatomite, separating liquid to obtain an organic phase, drying the organic phase through anhydrous magnesium sulfate, spin-drying, and purifying through column chromatography to obtain the compound 9-c (4,4'- (9,9' -spirobi [ fluoroene).]-2,7-diyl) bis (N-phenylaniline)) (9.22g, yield 70.7%), ms (ei): 650 (M)⁺)。

Under the protection of nitrogen, compound 9-c (1eq, 9g, 650.27g/mol, 13.84mmol), compound 9-d (2- (4-bromophenyl) -5, 5-diphenyl-5H-fluoroeno [2, 3-d)]Adding oxazole) (2eq, 14.2g, 513.07g/mol, 27.68mmol), sodium tert-butoxide (2.2eq, 2.93g, 96.1g/mol, 30.45mmol), tris (dibenzylideneacetone) dipalladium (0.05eq, 0.63g, 915g/mol, 0.69mmol), tri-tert-butylphosphine (0.05eq, 0.14g, 202.32g/mol, 0.69mol) and toluene (100ml) into a reaction bottle, heating to reflux reaction for 5h after the addition is finished, cooling to room temperature after the reaction is finished, adding 100ml of water, stirring for 15min, filtering to obtain a filtrate, separating the filtrate by diatomite to obtain an organic phase, drying the organic phase by anhydrous magnesium sulfate, spin-drying, and purifying to obtain an organic electroluminescent compound (79) (4,4'- (9,9' -spirobi [ fluorone ]]-2,7-diyl)bis(N-(4-(5,5-diphenyl-5H-fluoreno[2,3-d]oxazol-2-yl) phenyl) -N-phenylaniline) (9.36g, 44.6% yield), ms (ei): 1516 (M)⁺)。

Example 10:

the synthesis method of the organic electroluminescent compound (81) is as follows:

under the protection of nitrogen, compound 10-a (N4, N4'-diphenyl- [1,1' -biphenyl)]-4,4' -diamine) (1eq, 10.0g, 336.16g/mol, 29.75mmol), compound 10-b (2- (4-bromophenyl) -3-phenylquinoxaline) (2eq, 21.42g, 360.03g/mol, 59.49mmol), sodium tert-butoxide (2.2eq, 6.29g, 96.1g/mol, 65.45mmol), tris (dibenzylideneacetone) dipalladium (0.05eq, 1.36g, 915g/mol, 1.49mmol), tri-tert-butylphosphine (0.05eq, 0.3g, 202.32g/mol, 1.49mol), toluene (100ml) were added to a reaction flask, and the addition was completedHeating to reflux reaction for 5h, cooling to room temperature after the reaction is finished, adding 100ml of water, stirring for 15min, filtering to obtain a filtrate, filtering the filtrate by using kieselguhr, separating to obtain an organic phase, drying the organic phase by using anhydrous magnesium sulfate, spin-drying, and purifying by column chromatography to obtain the organic electroluminescent compound (81) (N4, N4' -diphenyl-N4, N4' -bis (4- (3-phenylquinoxalin-2-yl) phenyl) - [1,1' -biphenyl ] compound]-4,4' -diamine) (17.68g, yield 66.3%), ms (ei): 896 (M)⁺)。

Example 11:

the synthesis method of the organic electroluminescent compound (83) is as follows:

under the protection of nitrogen, compound 11-a (N4, N4'-diphenyl- [1,1' -biphenyl)]-4,4' -diamine) (1eq, 10.0g, 336.16g/mol, 29.75mmol), compound 11-b (2- (4-bromophen) -3- (phenanthren-2-yl) quinoxaline) (2eq, 27.37g, 460.06g/mol, 59.49mmol), sodium tert-butoxide (2.2eq, 6.29g, 96.1g/mol, 65.45mmol), tris (dibenzylideneacetone) dipalladium (0.05eq, 1.36g, 915g/mol, 1.49mmol), tri-tert-butylphosphine (0.05eq, 0.3g, 202.32g/mol, 1.49mol), toluene (100ml) were added to a reaction flask, after the addition was completed, the mixture was heated to reflux for 5h, after the reaction was completed, 100ml of water was added to the mixture, after 15min, the filtrate was filtered through celite to obtain an organic phase, after organic phase separation by column chromatography (dry phase chromatography, dry phase chromatography with anhydrous phase, 4, after organic phase separation by electroluminescence (3683), n4' -diphenyl-N4, N4' -bis (4- (3-phenylquinoxalin-2-yl) phenyl) - [1,1' -biphenyl]-4,4' -diamine) (20.12g, yield 61.7%), ms (ei): 1096 (M)⁺)。

Example 12:

the synthesis method of the organic electroluminescent compound (96) is as follows:

under the protection of nitrogen, compound 12-a (4,4' - (dibenzo [ b, d)]furan-3,7-diyl) bis (N-phenylalaniline)) (1eq, 10.0g, 502.2g/mol, 19.91mmol), compound 12-b (2- (4-bromophenyl) -3-phenylquinoline) (2eq, 14.3g, 359.03g/mol, 39.82mmol), sodium tert-butoxide (2.2eq, 4.21g, 96.1g/mol, 43.81mmol), tris (dibenzylideneacetone) dipalladium (0.05eq, 0.91g, 915g/mol, 1mmol), tri-tert-butylphosphine (0.05eq, 0.2g, 202.32g/mol, 1mol), toluene (100ml) were added to a reaction flask, after the addition, the temperature was raised to reflux reaction for 5h, after the reaction was completed, 100ml of water was added to room temperature, after 15min, the filtrate was filtered through celite, the organic phase was filtered, the organic phase was dried, and the organic phase was purified by spin chromatography (magnesium sulfate), 4' - (dibenzo [ b, d)]furan-3,7-diyl) bis (N-phenyl-N- (4- (3-phenylquinolin-2-yl) phenyl) aniline)) (14.18g, 67.2% yield, ms (ei): 1060 (M)⁺)。

Example 13:

the synthesis method of the organic electroluminescent compound (110) is as follows:

under the protection of nitrogen, compound 13-a (4,4'- (9,9' -spirobi [ fluoroene ])]-2,7-diyl) bis (N-phenylaniline)) (1eq, 10.0g, 650.27g/mol, 15.38mmol), compound 13-b (2- (4-bromophenyl) -3- (naphthalen-2-yl) quinoxaline) (2eq, 12.61g, 410.04g/mol, 30.76mmol), sodium tert-butoxide (2.2 eq)3.25g, 96.1g/mol, 33.83mmol), tris (dibenzylideneacetone) dipalladium (0.05eq, 0.7g, 915g/mol, 0.77mmol), tri-tert-butylphosphine (0.05eq, 0.16g, 202.32g/mol, 0.77mol), toluene (100ml) are added into a reaction bottle, after the addition is finished, the temperature is raised to reflux reaction for 5H, after the reaction is finished, 100ml of water is added to the reaction bottle to stir for 15min, filtrate is obtained, after the filtration of the filtrate, organic phase is obtained by separating after diatomite filtration, after drying by anhydrous magnesium sulfate, the organic phase is dried by spinning, after column chromatography purification, the organic electroluminescent compound (110) (4,4' - (9, 9-diphenyl-9H-fluorolene-2, 7-diphenyl) bis (N- (4- (3- (phenyl-2-yl) quinoxalin-2-yl) -N-phenyl)) (11.52 g), yield 57.1%), ms (ei): 1312 (M)⁺)。

Example 14:

the synthesis method of the organic electroluminescent compound (117) is as follows:

under the protection of nitrogen, adding compound 14-a (benzidine) (1eq, 10.0g, 184.1g/mol, 54.32mmol), compound 12-b (2- (4-bromophenyl) -3-phenylquinoline) (2eq, 39.11g, 360.03g/mol, 108.64mmol), sodium tert-butoxide (2.2eq, 11.48g, 96.1g/mol, 119.5mmol), tris (dibenzylideneacetone) dipalladium (0.05eq, 2.49g, 915g/mol, 2.72mmol), tri-tert-butylphosphine (0.05eq, 0.55g, 202.32g/mol, 2.72mol), toluene (100ml) into a reaction bottle, heating to reflux reaction for 5h after the reaction is finished, cooling to room temperature, adding 100ml of water, stirring for 15min, filtering to obtain a filtrate, filtering the filtrate through diatomite, filtering to obtain an organic phase, purifying by using anhydrous phase (4-25 mg) to obtain a purified compound, n4'-bis (4- (3-phenylquinoxalin-2-yl) phenyl) - [1,1' -biphenyl]-4,4' -diamine) (27.94g, yield 69.1%), ms (ei): 744 (M)⁺)。

Under the protection of nitrogen, compound 14-c (1eq, 27.0g, 744.3g/mol, 36.28mmol), compound 14-d (2- (4-bromophenyl) -5, 5-dimethyl-5H-fluoroeno [2, 3-d)]Adding oxazole) (2eq, 28.23g, 389.04g/mol, 72.55mmol), sodium tert-butoxide (2.2eq, 7.67g, 96.1g/mol, 79.8mmol), tris (dibenzylideneacetone) dipalladium (0.05eq, 1.66g, 915g/mol, 1.81mmol), tri-tert-butylphosphine (0.05eq, 0.37g, 202.32g/mol, 1.81mol) and toluene (100ml) into a reaction bottle, heating to reflux reaction for 5H after the addition is finished, cooling to room temperature after the reaction is finished, adding 100ml of water, stirring for 15min, filtering to obtain a filtrate, filtering the filtrate through kieselguhr to obtain an organic phase, drying the organic phase with anhydrous magnesium sulfate, spin-drying, and purifying to obtain an organic electroluminescent compound (117) (N4, N4' -bis (4- (5, 5-dimethyidene-fluoroeno [2, 3-fluo-d)]oxazol-2-yl)phenyl)-N4,N4'-bis(4-(3-phenylquinoxalin-2-yl)phenyl)-[1,1'-biphenyl]-4,4' -diamine) (26.88g, yield 54.4%), ms (ei): 1362 (M)⁺)。

Testing the performance of the compound:

the organic electroluminescent compounds 1, 4, 9, 17, 38, 47, 53, 66, 79, 81, 83, 96, 110, 117 of examples 1 to 14 of the present invention and the conventional materials CBP and TPBi were respectively subjected to thermal property and refractive index tests, and the glass transition temperature Tg and refractive index parameters are shown in table 1:

the glass transition temperature Tg was determined by differential scanning calorimetry (Shanghai Yingnuo precision instruments Co., Ltd., differential scanning calorimeter YND-BM2) at a heating rate of 10 ℃/min; the refractive index was measured by an ellipsometer (ME-L muller matrix ellipsometer, johns optical technology) and measured in an atmospheric environment.

Table 1:

testing the performance of the device:

application example 1:

adopting ITO as the anode substrate material of the reflecting layer, and sequentially using water, acetone and N₂Carrying out surface treatment on the glass substrate by plasma;

depositing HAT-CN with the thickness of 10nm to form a Hole Injection Layer (HIL) above the ITO anode substrate;

evaporating NPD above the Hole Injection Layer (HIL) to form a Hole Transport Layer (HTL) with the thickness of 120 nm;

evaporating ADN as blue light host material and BD-1 as blue light doping material (BD-1 amount is 5% of ADN weight) at different rates to form a light emitting layer with a thickness of 20nm on a Hole Transport Layer (HTL);

evaporating PBD on the light-emitting layer to obtain an Electron Transport Layer (ETL) with the thickness of 35nm, and evaporating LiQ with the thickness of 2nm above the Electron Transport Layer (ETL) to form an Electron Injection Layer (EIL);

then, magnesium (Mg) and silver (Ag) are mixed and evaporated in a ratio of 9:1 to obtain a cathode with the thickness of 15nm, an organic electroluminescent compound (1) with the thickness of 65nm is deposited on the sealing layer of the cathode to be used as a covering layer (CPL), and in addition, the surface of the cathode is sealed by a UV hardening adhesive and a sealing film (seal cap) containing a moisture remover so as to protect the organic electroluminescent device from oxygen or moisture in the atmosphere, thus preparing the organic electroluminescent device.

Application examples 2 to 14

Organic electroluminescent devices of application examples 2 to 14 were fabricated by using the organic electroluminescent compounds 4, 9, 17, 38, 47, 53, 66, 79, 81, 83, 96, 110, and 117 of examples 2 to 14 of the present invention as the capping layer (CPL), respectively, and the rest of the organic electroluminescent compounds were the same as in application example 1.

Comparative example 1

The difference from application example 1 is that TPBi is used as the capping layer (CPL), and the rest is the same as application example 1.

The characteristics of the organic electroluminescent device manufactured in the above application example and the organic electroluminescent device manufactured in the comparative example wereAt a current density of 10mA/cm²The results of measurements under the conditions of (1) are shown in Table 1.

Table 1:

as can be seen from table 1 and table 2 above, the organic electroluminescent compound of the present invention has a high glass transition temperature, good thermal stability and a high refractive index, and when applied to an organic electroluminescent device, the organic electroluminescent compound has a certain improvement in luminous efficiency, a reduction in the starting voltage of the device, a relative reduction in power consumption, and a corresponding improvement in the service life, under the same current density.