CN110835532B - Organic electroluminescent compound, preparation method thereof and organic electroluminescent device - Google Patents

Abstract

The invention relates to an organic electroluminescent compound, a preparation method thereof and an organic electroluminescent device, belonging to the technical field of luminescent materials. The invention provides an organic electroluminescent compound, the structural formula of which is shown in chemical formula 1:

Description

Organic electroluminescent compound, preparation method thereof and organic electroluminescent device

Technical Field

The invention relates to the technical field of luminescent materials, in particular to an organic electroluminescent compound, a preparation method thereof and an organic electroluminescent device.

Background

An electroluminescent device (EL device) is an automatic light emitting device, which is advantageous in that it provides a wide viewing angle, a large contrast ratio, and a fast response time.

The organic EL element is a self-luminous element utilizing the following principle: by applying an electric field, the fluorescent substance emits light by the recombination energy of holes injected from the anode and electrons injected from the cathode. It has a structure of an anode, a cathode and an organic material layer interposed therebetween. In order to improve efficiency and stability of the organic EL element, the organic material layer includes a plurality of layers having different materials, such as a Hole Injection Layer (HIL), a Hole Transport Layer (HTL), an emission layer, an Electron Transport Layer (ETL), and an Electron Injection Layer (EIL).

In such an organic EL device, when a voltage is applied between an anode and a cathode, holes from the anode and electrons from the cathode are injected into the organic material layer. The generated excitons generate light having a specific wavelength while migrating to a ground state.

The most important factor determining the luminous efficiency of an organic EL device is a light emitting material. Up to now, fluorescent materials have been widely used as light emitting materials. However, in view of the mechanism of electroluminescence, since phosphorescent materials theoretically enhance the luminous efficiency four times as compared to fluorescent materials, the development of phosphorescent light emitting materials has been widely studied. Iridium (III) complexes have been widely referred to as phosphorescent dopant materials. Currently, 4,4'-N, N' -dicarbazole-biphenyl (CBP), 9,10-bis (2-naphthyl) Anthracene (ADN), etc. are widely used as known phosphorescent host materials. However, organic EL devices of these materials are required to be further improved in quantum efficiency and service life.

Disclosure of Invention

The invention provides an organic electroluminescent compound, a preparation method thereof and an organic electroluminescent device, aiming at solving the technical problems of unsatisfactory quantum efficiency and service life of the existing organic EL device.

In order to solve the technical problems, the technical scheme of the invention is as follows:

the invention provides an organic electroluminescent compound, the structural formula of which is shown in chemical formula 1:

in the formula:

l represents a bond, a substituted or unsubstituted aryl, or a substituted or unsubstituted heteroaryl;

ar represents a substituted or unsubstituted aryl group, or a substituted or unsubstituted heteroaryl group;

Ar ₁ and Ar ₂ Each independently represents a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted alkynyl group, or a substituted or unsubstitutedA substituted aryl group;

R ₁ -R ₉ each independently represents hydrogen, deuterium, halogen, cyano, carboxyl, nitro, hydroxyl, substituted or unsubstituted alkyl, substituted or unsubstituted alkenyl, substituted or unsubstituted alkynyl, substituted or unsubstituted alkoxy, substituted or unsubstituted cycloalkyl, substituted or unsubstituted cycloalkenyl, substituted or unsubstituted heterocycloalkyl, substituted or unsubstituted aryl, or substituted or unsubstituted heteroaryl.

In the above-mentioned technical scheme, L preferably represents a bond, a substituted or unsubstituted C6-C30 aryl group, or a substituted or unsubstituted C3-C30 heteroaryl group.

In the above technical scheme, it is preferable that L is linked to an adjacent substituent to form a monocyclic or polycyclic ring, specifically, a C6-C30 aromatic ring, a C3-C30 aromatic heterocycle, or a C3-C30 aliphatic ring, and a carbon atom thereon may be substituted with N, O, S, or a Si heteroatom.

In the above-mentioned technical scheme, ar preferably represents a substituted or unsubstituted C6-C30 aryl group, or a substituted or unsubstituted C3-C30 heteroaryl group.

In the above technical scheme, it is preferable that Ar is linked with an adjacent substituent to form a monocyclic or polycyclic ring, specifically, a C6-C30 aromatic ring, a C3-C30 aromatic heterocyclic ring, or a C3-C30 aliphatic ring, and a carbon atom thereon may be substituted with N, O, S, or a Si heteroatom.

In the above-mentioned technical solutions, ar is preferred ₁ And Ar ₂ Each independently represents a substituted or unsubstituted C1-C30 alkyl group, a substituted or unsubstituted C2-C30 alkenyl group, a substituted or unsubstituted C2-C30 alkynyl group, or a substituted or unsubstituted C6-C30 aryl group.

In the above-mentioned technical solutions, ar is preferred ₁ And Ar ₂ Are respectively connected with adjacent substituents to form a monocyclic ring or a polycyclic ring, in particular a C6-C30 aromatic ring, a C3-C30 aromatic heterocycle or a C3-C30 aliphatic ring, and carbon atoms on the aromatic ring can be substituted by N, O, S or a Si heteroatom.

In the above technical solutions, R is preferable ₁ -R ₉ Each independently represents hydrogen, deuterium,Halogen, cyano, carboxyl, nitro, hydroxyl, substituted or unsubstituted C1-C30 alkyl, substituted or unsubstituted C2-C30 alkenyl, substituted or unsubstituted C2-C30 alkynyl, substituted or unsubstituted C1-C30 alkoxy, substituted or unsubstituted C3-C30 cycloalkyl, substituted or unsubstituted C3-C30 cycloalkenyl, substituted or unsubstituted C3-C7 heterocycloalkyl, substituted or unsubstituted C6-C30 aryl, or substituted or unsubstituted C3-C30 heteroaryl.

In the above technical solutions, R is preferred ₁ -R ₉ Are linked to adjacent substituents to form a mono-or polycyclic, specifically a C3-C30 aliphatic or aromatic ring, the carbon atoms of which may be replaced by one or more of nitrogen, oxygen, sulfur, and silicon heteroatoms.

"substituted or unsubstituted" in the present invention means substituted with one, two or more substituents selected from the group consisting of: deuterium, a halogen group, a nitrile group, a hydroxyl group, a carbonyl group, an ester group, a silyl group, a boron group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted alkylamino group, a substituted or unsubstituted heteroarylamino group, a substituted or unsubstituted arylamino group, a substituted or unsubstituted aryl group, and a substituted or unsubstituted heterocyclic group, or a substituent connected by two or more substituents among the substituents shown above, or no substituent. For example, "a substituent in which two or more substituents are linked" may include a biphenyl group. In other words, biphenyl can be an aryl group, or can be interpreted as a substituent with two phenyl groups attached.

In the above technical solution, it is most preferable that the organic electroluminescent compound is selected from any one of compounds having structures represented by chemical formulas 1 to 76:

the invention also provides a preparation method of the organic electroluminescent compound, which comprises the following steps:

step 1, preparation of intermediate 1

Adding a palladium catalyst, tri-tert-butylphosphine and sodium tert-butoxide into the compound 1, the compound 2 and toluene in a nitrogen atmosphere, heating, stirring, and obtaining an intermediate 1 after the reaction is finished;

step 2, preparation of intermediate 2

After the intermediate 1 and THF were added to the reaction vessel, the air was sufficiently replaced with nitrogen three times; adding the grignard reagent dropwise to the aforementioned mixture; the mixture is stirred at room temperature, and an intermediate 2 is obtained after the reaction is finished;

step 3, preparation of intermediate 3

Dissolving the intermediate 2 in a mixed solvent of THF and toluene, adding MSA dropwise into the mixture after adding the intermediate into a reaction vessel; stirring the mixture at room temperature to obtain an intermediate 3 after the reaction is finished;

step 4, preparation of compound represented by chemical formula 1

After the intermediate 3 and the compound 3 were added to the reaction vessel, air was sufficiently replaced with nitrogen three times; adding a palladium catalyst, tri-tert-butylphosphine and sodium tert-butoxide in a nitrogen atmosphere, heating and stirring, and obtaining a compound shown in chemical formula 1 after the reaction is finished;

the synthetic route is as follows:

l, ar and Ar in the synthetic route ₁ 、Ar ₂ And R ₁ -R ₉ The same as the range defined in the aforementioned chemical formula 1, and thus, the detailed description thereof will be omitted.

In the above-mentioned technical solution,

the step 1 specifically comprises the following steps: adding a compound 1, a compound 2 and toluene into a reaction container, adding a palladium catalyst, tri-tert-butylphosphine and sodium tert-butoxide in a nitrogen atmosphere, heating to 110 ℃, and stirring for 5h; extracting the reaction solution with ethyl acetate; the extracted organic layer was then dried with magnesium sulfate and the solvent was removed using a rotary evaporator; purifying the remaining material by column chromatography to obtain intermediate 1;

the step 2 specifically comprises the following steps:

after the intermediate 1 and THF were added to the reaction vessel, the air was sufficiently replaced with nitrogen three times; adding the grignard reagent dropwise to the aforementioned mixture at 0 ℃; after stirring the mixture at room temperature for 2 hours, quenching with distilled water, and extracting the mixture with dichloromethane; the extracted organic layer was then dried with sodium sulfate and the solvent was removed using a rotary evaporator; purifying the remaining material by column chromatography to obtain intermediate 2;

the step 3 specifically comprises the following steps:

dissolving the intermediate 2 in a mixed solvent of THF and toluene, adding MSA dropwise into the mixture after adding the intermediate into a reaction vessel; after stirring the mixture at room temperature for 5 hours, quenching with distilled water, and extracting the mixture with dichloromethane; the extracted organic layer was then dried with sodium sulfate and the solvent was removed using a rotary evaporator; purifying the remaining material by column chromatography to obtain intermediate 3;

the step 4 specifically comprises the following steps:

after the intermediate 3 and the compound 3 were added to the reaction vessel, air was sufficiently replaced with nitrogen three times; adding a palladium catalyst, tri-tert-butylphosphine and sodium tert-butoxide in a nitrogen atmosphere, heating to 110 ℃, and stirring for 5 hours; extracting the reaction solution with ethyl acetate; the extracted organic layer was then dried with magnesium sulfate and the solvent was removed using a rotary evaporator; purifying the remaining material by column chromatography to obtain the compound represented by chemical formula 1.

The invention also provides an organic electroluminescent device prepared from the organic electroluminescent compound.

The organic electroluminescent device described above includes: the organic electroluminescent device comprises a first electrode, a second electrode and an organic layer arranged between the two electrodes, wherein the organic layer comprises the organic electroluminescent compound.

The organic layer at least comprises one or more of a hole injection layer, a hole transport layer, an electron blocking layer, a luminescent layer, a hole blocking layer, an electron transport layer, an electron injection layer and a layer which has both electron transport and electron injection functions.

The organic electroluminescent device comprises a light-emitting layer, wherein the light-emitting layer contains the organic electroluminescent compound.

The device of the invention can be used for an organic light-emitting device, an organic solar cell, electronic paper, an organic photoreceptor or an organic thin film transistor.

The invention has the beneficial effects that:

the present invention provides an organic electroluminescent compound of a novel structure, and a device prepared from the compound has excellent current efficiency and power efficiency and a long life.

The preparation method of the organic electroluminescent compound provided by the invention has the advantages of simple process and high product purity.

Detailed Description

Example 1: preparation of Compound 1

Adding into a reaction vessel2-Bromoquinoline (60 mmol) and o-aminoacetophenone (60 mmol) were dissolved in 200mL of toluene, and Pd was added under a nitrogen atmosphere ₂ (dba) ₃ (0.6mmol)、P(t-Bu) ₃ (3 mmol) and t-BuONa (180 mmol). After the addition, the reaction temperature was slowly raised to 110 ℃, and the mixture was stirred for 10 hours. Distilled water was then added to the reaction solution and the reaction solution was extracted with ethyl acetate. The extracted organic layer was then dried with magnesium sulfate and the solvent was removed using a rotary evaporator. The remaining material was purified by column chromatography to obtain compound 1-1 (12 g, 76% yield).

After compound 1-1 (45.7 mmol) and 100ml THF were added to the reaction vessel, the temperature was lowered to 0 deg.C and methylmagnesium bromide (222.5 mmol) was slowly added dropwise to the mixture. After stirring the mixture at room temperature for 2 hours, it was quenched with distilled water, and the mixture was extracted with dichloromethane. The extracted organic layer was then dried over sodium sulfate and the solvent was removed using a rotary evaporator. The remaining material was purified by column chromatography to obtain compound 1-2 (10 g, 78.6% yield).

Compound 1-2 (35.9 mmol) was added to the reaction vessel with 50mL of THF and 50mL of toluene, and MSA (359 mmol) was added to the reaction solution. After stirring the mixture at room temperature for 2 hours, it was quenched with distilled water, and the mixture was extracted with dichloromethane. The extracted organic layer was then dried over sodium sulfate and the solvent was removed using a rotary evaporator. The remaining material was purified by column chromatography to obtain compounds 1-3 (7 g, 74.9% yield).

Adding compound 1-3 (26.88 mmol), iodobenzene and 70mL toluene into a reaction vessel, and adding Pd under nitrogen atmosphere ₂ (dba) ₃ (0.27mmol)、P(t-Bu) ₃ (1.35 mmol) and t-BuONa (81 mmol). After the addition, the reaction temperature was slowly raised to 110 ℃, and the mixture was stirred for 10 hours. Distilled water was then added to the reaction solution and the reaction solution was extracted with ethyl acetate. The extracted organic layer was then dried with magnesium sulfate and the solvent was removed using a rotary evaporator. The remaining material was purified by column chromatography to obtain compound 1 (6 g, 66% yield).

Example 2: preparation of Compound 8

After 2-bromoquinoline (60 mmol) and o-aminoacetophenone (60 mmol) were added to a reaction vessel and dissolved in 200mL of toluene, pd was added under a nitrogen atmosphere ₂ (dba) ₃ (0.6mmol)、P(t-Bu) ₃ (3 mmol), t-BuONa (180 mmol). After the addition, the reaction temperature was slowly raised to 110 ℃, and the mixture was stirred for 10 hours. Distilled water was then added to the reaction solution and the reaction solution was extracted with ethyl acetate. The extracted organic layer was then dried with magnesium sulfate, and the solvent was removed using a rotary evaporator. The remaining material was purified by column chromatography to obtain compound 8-1 (12.6 g, 80% yield).

After compound 8-1 (45.7 mmol) and 100mL THF were added to the reaction vessel, the temperature was reduced to 0 deg.C and methylmagnesium bromide (222.5 mmol) was slowly added dropwise to the mixture. After stirring the mixture at room temperature for 2 hours, it was quenched with distilled water, and the mixture was extracted with dichloromethane. The extracted organic layer was then dried over sodium sulfate and the solvent was removed using a rotary evaporator. The remaining material was purified by column chromatography to obtain compound 8-2 (10.2 g, 80.0% yield).

Compound 8-2 (35.9 mmol) was added to the reaction vessel with 50mL of THF and 50mL of toluene, and MSA (359 mmol) was added to the reaction solution. After stirring the mixture at room temperature for 2 hours, it was quenched with distilled water, and the mixture was extracted with dichloromethane. The extracted organic layer was then dried over sodium sulfate and the solvent was removed using a rotary evaporator. The remaining material was purified by column chromatography to obtain compound 8-3 (7.5 g, yield 80.1%).

Adding the compound 8-3 (26.88 mmol), 8-4 and 70mL of toluene into a reaction vessel, and adding Pd under nitrogen atmosphere ₂ (dba) ₃ (0.27mmol)、P(t-Bu) ₃ (1.35 mmol) and t-BuONa (81 mmol). After the addition, the reaction temperature was slowly raised to 110 ℃, and the mixture was stirred for 10 hours. Distilled water was then added to the reaction solution and the reaction solution was extracted with ethyl acetate. Followed by drying and extraction with magnesium sulfateThe organic layer was taken and the solvent was removed using a rotary evaporator. The remaining material was purified by column chromatography to obtain compound 8 (9.4 g, 85% yield).

Example 3: preparation of Compound 11

After 2-bromoquinoline (60 mmol) and o-aminoacetophenone (60 mmol) were added to a reaction vessel and dissolved in 200mL of toluene, pd was added under a nitrogen atmosphere ₂ (dba) ₃ (0.6mmol)、P(t-Bu) ₃ (3 mmol) and t-BuONa (180 mmol). After the addition, the reaction temperature was slowly raised to 110 ℃, and the mixture was stirred for 10 hours. Distilled water was then added to the reaction solution and the reaction solution was extracted with ethyl acetate. The extracted organic layer was then dried with magnesium sulfate, and the solvent was removed using a rotary evaporator. The remaining material was purified by column chromatography to obtain compound 11-1 (13.1 g, 83% yield).

After compound 11-1 (45.7 mmol) and 100mL THF were added to the reaction vessel, the temperature was reduced to 0 deg.C and methylmagnesium bromide (222.5 mmol) was slowly added dropwise to the mixture. After stirring the mixture at room temperature for 2 hours, it was quenched with distilled water, and the mixture was extracted with dichloromethane. The extracted organic layer was then dried over sodium sulfate and the solvent was removed using a rotary evaporator. The remaining material was purified by column chromatography to obtain compound 11-2 (10.4 g, yield 82.0%).

Compound 11-2 (35.9 mmol) was added to a reaction vessel along with 50mL of THF and 50mL of toluene, and MSA (359 mmol) was added to the reaction solution. After stirring the mixture at room temperature for 2 hours, it was quenched with distilled water, and the mixture was extracted with dichloromethane. The extracted organic layer was then dried over sodium sulfate and the solvent was removed using a rotary evaporator. The remaining material was purified by column chromatography to obtain compound 11-3 (7.6 g, yield 81.0%).

Adding compound 11-3 (26.88 mmol), 11-4 and 70mL of toluene into a reaction vessel, and adding Pd under nitrogen atmosphere ₂ (dba) ₃ (0.27mmol)、P(t-Bu) ₃ (1.35 mmol), t-BuONa (81 mmol). After the addition, the reaction temperature was slowly raised to 110 ℃, and the mixture was stirred for 10 hours. Distilled water was then added to the reaction solution and the reaction solution was extracted with ethyl acetate. The extracted organic layer was then dried with magnesium sulfate and the solvent was removed using a rotary evaporator. The remaining material was purified by column chromatography to obtain compound 11 (11.2 g, 83% yield).

Example 4: preparation of Compound 24

After 2-bromoquinoline (60 mmol) and o-aminoacetophenone (60 mmol) were added to a reaction vessel and dissolved in 200mL of toluene, pd was added under a nitrogen atmosphere ₂ (dba) ₃ (0.6mmol)、P(t-Bu) ₃ (3 mmol) and t-BuONa (180 mmol). After the addition, the reaction temperature was slowly raised to 110 ℃, and the mixture was stirred for 10 hours. Distilled water was then added to the reaction solution and the reaction solution was extracted with ethyl acetate. The extracted organic layer was then dried with magnesium sulfate and the solvent was removed using a rotary evaporator. The remaining material was purified by column chromatography to obtain compound 24-1 (13.2 g, 84% yield).

After compound 24-1 (45.7 mmol) and 100mL THF were added to the reaction vessel, the temperature was lowered to 0 deg.C and methyl magnesium bromide (222.5 mmol) was slowly added dropwise to the mixture. After stirring the mixture at room temperature for 2 hours, it was quenched with distilled water, and the mixture was extracted with dichloromethane. The extracted organic layer was then dried over sodium sulfate and the solvent was removed using a rotary evaporator. The remaining material was purified by column chromatography to obtain compound 24-2 (10.6 g, yield 83.0%).

Compound 24-2 (35.9 mmol) was added to the reaction vessel with 50mL of THF and 50mL of toluene, and MSA (359 mmol) was added to the reaction solution. After stirring the mixture at room temperature for 2 hours, it was quenched with distilled water, and the mixture was extracted with dichloromethane. The extracted organic layer was then dried over sodium sulfate and the solvent was removed using a rotary evaporator. The remaining material was purified by column chromatography to obtain compound 24-3 (7.7 g, yield 82.0%).

Adding compound 24-3 (26.88 mmol), 23-4 and 70mL of toluene into a reaction vessel, and adding Pd under nitrogen atmosphere ₂ (dba) ₃ (0.27mmol)、P(t-Bu) ₃ (1.35 mmol), t-BuONa (81 mmol). After the addition, the reaction temperature was slowly raised to 110 ℃, and the mixture was stirred for 10 hours. Distilled water was then added to the reaction solution and the reaction solution was extracted with ethyl acetate. The extracted organic layer was then dried with magnesium sulfate and the solvent was removed using a rotary evaporator. The remaining material was purified by column chromatography to obtain compound 24 (10.2 g, 82.0% yield).

Example 5: preparation of Compound 48

After 2-bromoquinoline (60 mmol) and compound A (60 mmol) were dissolved in 200mL of toluene in a reaction vessel, pd was added under a nitrogen atmosphere ₂ (dba) ₃ (0.6mmol)、P(t-Bu) ₃ (3 mmol), t-BuONa (180 mmol). After the addition, the reaction temperature was slowly raised to 110 ℃, and the mixture was stirred for 10 hours. Distilled water was then added to the reaction solution and the reaction solution was extracted with ethyl acetate. The extracted organic layer was then dried with magnesium sulfate and the solvent was removed using a rotary evaporator. The remaining material was purified by column chromatography to obtain compound 48-1 (16.9 g, 83.0% yield).

After compound 48-1 (45.7 mmol) and 100mL THF were added to the reaction vessel, the temperature was lowered to 0 deg.C and methyl magnesium bromide (222.5 mmol) was slowly added dropwise to the mixture. After stirring the mixture at room temperature for 2 hours, it was quenched with distilled water, and the mixture was extracted with dichloromethane. The extracted organic layer was then dried over sodium sulfate and the solvent was removed using a rotary evaporator. The remaining material was purified by column chromatography to obtain compound 48-2 (13.5 g, 83.0% yield).

Compound 48-2 (35.9 mmol) was added to the reaction vessel with 50mL of THF and 50mL of toluene, and MSA (359 mmol) was added to the reaction solution. After stirring the mixture at room temperature for 2 hours, it was quenched with distilled water, and the mixture was extracted with dichloromethane. The extracted organic layer was then dried over sodium sulfate and the solvent was removed using a rotary evaporator. The remaining material was purified by column chromatography to obtain compound 48-3 (9.9 g, yield 82.0%).

Compound 48-3 (26.88 mmol), 48-4 and 70mL of toluene were added to a reaction vessel, and Pd was added under a nitrogen atmosphere ₂ (dba) ₃ (0.27mmol)、P(t-Bu) ₃ (1.35 mmol) and t-BuONa (81 mmol). After the addition, the reaction temperature was slowly raised to 110 ℃, and the mixture was stirred for 10 hours. Distilled water was then added to the reaction solution and the reaction solution was extracted with ethyl acetate. The extracted organic layer was then dried with magnesium sulfate, and the solvent was removed using a rotary evaporator. The remaining material was purified by column chromatography to obtain compound 48 (11.7 g, 81.0% yield).

The synthesis methods of other compounds are the same as those described above, which are not repeated herein, and the mass spectrum data of the prepared compounds are shown in the following table 1:

table 1: examples preparation of compounds mass spectral data:

compound (I)	Molecular formula	Theoretical value of mass spectrum	Mass spectrometric test values
				1	C 24 H 20 N 2	336.16	336.10
2	C 28 H 22 N 2	386.18	386.20
				5	C 27 H 21 N 3	387.17	387.22
8	C 29 H 23 N 3	413.19	413.14
				11	C 36 H 31 N 3	505.25	505.34
12	C 39 H 29 N 5	576.24	576.28
				13	C 30 H 24 N 2	412.19	412.20
15	C 33 H 25 N 5	491.21	491.24
				18	C 29 H 23 N 3	413.19	413.23
24	C 34 H 24 N 2	460.19	460.24
				30	C 33 H 25 N 3	463.20	463.22
42	C 34 H 26 N 4	490.22	490.18
				48	C 39 H 27 N 3	537.22	537.25

Example 6: production of organic electroluminescent devices comprising Compound 1

Coating with a thickness of

ITO glass substrateWashing with distilled water for 2 times, ultrasonic washing for 30 minutes, repeatedly washing with distilled water for 2 times, ultrasonic washing for 10 minutes, after the completion of the distilled water washing, ultrasonic washing with solvents such as isopropyl alcohol, acetone, and methanol in this order, drying, transferring to a plasma cleaning machine, washing the substrate for 5 minutes, and transferring to a deposition machine. First, vapor deposition is carried out on the ITO (anode)

Followed by evaporation

Compound 1 and doping substance Ir (ppy) ₃ 95 weight ratio

Vapor deposition electron transport layer

Vapor deposition of electron injection layer

Evaporation cathode

And (4) preparing the organic electroluminescent device. The performance luminescence characteristics of the obtained device are tested by adopting a KEITHLEY 2400 type source measuring unit and a CS-2000 spectral radiance luminance meter to evaluate the driving voltage, the luminescence efficiency and the service life of the device.

By referring to the above-mentioned methods, the organic electroluminescent devices of the corresponding compounds were prepared by replacing compound 1 with 2, 5, 8, 11, 12, 13, 15, 18, 24, 30, 42, 48, respectively.

Comparative example 1:

an organic electroluminescent device was prepared in the same manner as in example 6, and the green host compound had the following structure:

the same examination as in example 6 was performed on the prepared organic electroluminescent device, and the results are shown in table 2.

Table 2 test results of organic electroluminescent devices in example 6 and comparative example 1

As can be seen from table 2, the organic electroluminescent device prepared using the compound provided by the present invention as a green host material has significantly reduced driving voltage, reduced current density, and significantly improved lifetime, compared to the organic electroluminescent device prepared using the comparative compound CBP as a green host material.

The above description of the embodiments is only intended to facilitate the understanding of the method of the invention and its core idea. It should be noted that, for those skilled in the art, it is possible to make various improvements and modifications to the present invention without departing from the principle of the present invention, and those improvements and modifications also fall within the scope of the claims of the present invention.

Claims (6)

1. An organic electroluminescent compound, characterized in that its structural formula is shown in chemical formula 1:

in the formula:

l represents a bond, a substituted or unsubstituted C6-C30 aryl, or a substituted or unsubstituted C3-C30 heteroaryl;

ar represents a substituted or unsubstituted C6-C30 aryl group, or a substituted or unsubstituted C3-C30 heteroaryl group;

Ar ₁ and Ar ₂ Each independently represents a substituted or unsubstituted C1-C2 alkyl group, or a substituted or unsubstituted C6-C30 aryl group; r ₁ -R ₆ ，R ₈ -R ₉ Each independently represents hydrogen;

R ₇ represents hydrogen, deuterium, substituted or unsubstituted C1-C30 alkyl, substituted or unsubstituted C6-C30 aryl, or substituted or unsubstituted C3-C30 heteroaryl.

2. The organic electroluminescent compound according to claim 1, wherein L is linked to an adjacent substituent to form a monocyclic or polycyclic ring, specifically a C6-C30 aromatic ring, a C3-C30 aromatic heterocyclic ring, or a C3-C30 aliphatic ring, and a carbon atom thereof is substituted with N, O, S, or a Si heteroatom;

or:

ar is connected with adjacent substituent groups to form a monocyclic ring or polycyclic ring, in particular a C6-C30 aromatic ring, a C3-C30 aromatic heterocycle or a C3-C30 aliphatic ring, and carbon atoms on the aromatic ring or the C3-C30 aliphatic ring are substituted by N, O, S or Si heteroatom;

or:

Ar ₁ and Ar ₂ Respectively connected with adjacent substituents to form a monocyclic ring or a polycyclic ring, specifically a C6-C30 aromatic ring, a C3-C30 aromatic heterocycle or a C3-C30 aliphatic ring, and carbon atoms thereon are substituted by N, O, S or a Si heteroatom;

or:

R ₁ -R ₉ are linked to adjacent substituents to form a mono-or polycyclic, specifically a C3-C30 aliphatic or aromatic ring, wherein the carbon atoms are replaced with one or more heteroatoms selected from nitrogen, oxygen, sulfur and silicon.

3. The organic electroluminescent compound according to claim 1, wherein the compound is any one selected from compounds having a structure represented by chemical formula 1 to 76:

4. a method for preparing the organic electroluminescent compound according to any one of claims 1 to 3, comprising the steps of:

step 1, preparation of intermediate 1

Adding a palladium catalyst, tri-tert-butylphosphine and sodium tert-butoxide into the compound 1, the compound 2 and toluene in a nitrogen atmosphere, heating and stirring, and obtaining an intermediate 1 after the reaction is finished;

step 2, preparation of intermediate 2

After the intermediate 1 and THF were added to the reaction vessel, the air was sufficiently replaced with nitrogen three times; adding the grignard reagent dropwise to the aforementioned mixture; the mixture is stirred at room temperature, and an intermediate 2 is obtained after the reaction is finished;

step 3, preparation of intermediate 3

Dissolving the intermediate 2 in a mixed solvent of THF and toluene, adding MSA dropwise into the mixture after adding the intermediate into a reaction vessel; stirring the mixture at room temperature to obtain an intermediate 3 after the reaction is finished;

step 4, preparation of compound shown in chemical formula 1

After the intermediate 3 and the compound 3 were added to the reaction vessel, air was sufficiently replaced with nitrogen three times; adding a palladium catalyst, tri-tert-butylphosphine and sodium tert-butoxide in a nitrogen atmosphere, heating and stirring to obtain a compound shown in chemical formula 1 after the reaction is finished;

the synthetic route is as follows:

5. the method for producing an organic electroluminescent compound according to claim 4,

the step 1 specifically comprises the following steps: adding a compound 1, a compound 2 and toluene into a reaction container, adding a palladium catalyst, tri-tert-butylphosphine and sodium tert-butoxide in a nitrogen atmosphere, heating to 110 ℃, and stirring for 5 hours; extracting the reaction solution with ethyl acetate; the extracted organic layer was then dried with magnesium sulfate and the solvent was removed using a rotary evaporator; purifying the remaining material by column chromatography to obtain intermediate 1;

the step 2 specifically comprises the following steps:

after the intermediate 1 and THF were added to the reaction vessel, the air was sufficiently replaced with nitrogen three times; adding the grignard reagent dropwise to the aforementioned mixture at 0 ℃; after stirring the mixture at room temperature for 2 hours, quenching with distilled water, and extracting the mixture with dichloromethane; the extracted organic layer was then dried with sodium sulfate and the solvent was removed using a rotary evaporator; purifying the remaining material by column chromatography to obtain intermediate 2;

the step 3 specifically comprises the following steps:

dissolving the intermediate 2 in a mixed solvent of THF and toluene, adding MSA dropwise into the mixture after adding the intermediate into a reaction vessel; after stirring the mixture at room temperature for 5 hours, quenching with distilled water, and extracting the mixture with dichloromethane; the extracted organic layer was then dried with sodium sulfate and the solvent was removed using a rotary evaporator; purifying the remaining material by column chromatography to obtain intermediate 3;

the step 4 specifically comprises the following steps:

after the intermediate 3 and the compound 3 were added to the reaction vessel, air was sufficiently replaced with nitrogen three times; adding a palladium catalyst, tri-tert-butylphosphine and sodium tert-butoxide in a nitrogen atmosphere, heating to 110 ℃, and stirring for 5 hours; extracting the reaction solution with ethyl acetate; the extracted organic layer was then dried with magnesium sulfate and the solvent was removed using a rotary evaporator; purifying the remaining material by column chromatography to obtain the compound represented by chemical formula 1.

6. An organic electroluminescent device prepared from the organic electroluminescent compound according to any one of claims 1 to 3.