Heteroatom-containing spirocyclic organic electroluminescent compound, preparation method and application

Abstract

The present invention relates to a spiro-type organic electroluminescent compound containing heteroatoms, a preparation method and an application thereof, and belongs to the technical field of organic luminescent materials. The general structural formula of the spiro-type organic electroluminescent compound containing heteroatoms is Formula 1: #imgabs0# The present invention provides a spiro-type organic electroluminescent compound containing heteroatoms. The compound has high electron injection and mobility rates, and has good film-forming properties and thermal stability. When used in the electron transport layer of an organic electroluminescent device, the compound can significantly improve the electron transport efficiency from the electron transport layer to the light-emitting layer, thereby improving the luminous efficiency, while reducing the driving voltage and extending the service life of the device.

Description

Technical Field

[0001] The present invention relates to the technical field of organic luminescent materials, in particular to a spiro organic electroluminescent compound containing heteroatoms, a preparation method and an application thereof. Background Art

[0002] Organic Light Emitting Diode (OLED) is a new and promising display technology that has gradually entered people's field of vision. OLED is an electroluminescent device formed by a multi-layer organic thin film structure.

[0003] An organic electroluminescent element is a self-luminous element that utilizes the following principle: by applying an electric field, the fluorescent substance emits light by utilizing the recombination energy of holes injected from the anode and electrons injected from the cathode. It has the following structure: an anode, a cathode, and an organic material layer between the two. In order to improve the efficiency and stability of the organic electroluminescent element, the organic material layer generally includes multiple layers with different materials, such as a hole injection layer (HIL), a hole transport layer (HTL), a light-emitting layer, an electron transport layer (ETL), and an electron injection layer (EIL). In this type of organic light-emitting element, when a voltage is applied between the anode and the cathode, holes from the anode and electrons from the cathode are injected into the organic material layer, and the generated excitons generate light with a specific wavelength when they migrate to the ground state. The structure of the electron transport materials currently used as electron transport layers usually contains nitrogen-containing heterocycles such as pyridine, pyrimidine, oxadiazole, triazole, imidazole, and electron-withdrawing groups such as phosphorus oxide, which have electron transport properties. As a key component of the OLED structure, the electron transport layer will also have a great impact on the life of the device. For example, the mobility and band structure of the material determine the local electric field, carrier and Joule heat distribution in the electron transport layer and its vicinity, thereby directly affecting the aging rate of organic materials and devices.

[0004] Research on organic electroluminescent materials has been widely carried out in academia and industry, but so far, stable and efficient organic layer materials for organic electrical components have not been fully developed, and the industrialization process of this technology still faces many key problems. Therefore, the development of new materials has always been an urgent problem to be solved by technical personnel in this field. Summary of the Invention

[0005] The purpose of the present invention is to provide a spirocyclic organic electroluminescent compound containing a heteroatom, a preparation method and an application thereof, so as to solve the problems raised in the above background technology.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] The spirocyclic organic electroluminescent compound containing a heteroatom has the general structural formula 1:

[0008]

[0009] Wherein, n is 0, 1, 2 or 3, m is 0, 1, 2, 3 or 4, and n and m are not 0 at the same time;

[0010] L1 and L2 are the same or different and are independently a linking bond; substituted or unsubstituted C6-C 30 arylene; substituted or unsubstituted C3-C 30 heteroarylene;

[0011] R1, R2, and R3 are 0-4 substituents, R1-R3 are the same or different, and R1-R3 are independently hydrogen, deuterium, halogen, cyano, carboxyl, nitro, hydroxyl, amino, silicon, or borane; substituted or unsubstituted C1-C 30 Alkyl; substituted or unsubstituted C2-C 30 Alkenyl; substituted or unsubstituted C2-C 30 Alkynyl; substituted or unsubstituted C3-C 30 Cycloalkyl; substituted or unsubstituted 3-30 membered heterocycloalkyl, the heteroatom of which is selected from oxygen, nitrogen or sulfur; substituted or unsubstituted C6-C 30 Aryl; substituted or unsubstituted 3-20 membered heteroaryl, whose heteroatom is selected from oxygen, nitrogen or sulfur; substituted or unsubstituted 3-25 membered heteroarylamino, whose heteroatom is selected from oxygen, nitrogen, sulfur; substituted or unsubstituted C6-C 60 arylamine group;

[0012] Ar1 and Ar2 are the same or different from each other, and Ar1 and Ar2 are independently substituted or unsubstituted C3-C 30 Cycloalkyl; substituted or unsubstituted 3-20 membered heterocycloalkyl, the heteroatom of which is selected from oxygen, nitrogen or sulfur; substituted or unsubstituted C6-C 30 aryl; a substituted or unsubstituted 3- to 30-membered heteroaryl group, wherein the heteroatom is selected from oxygen, nitrogen or sulfur; a substituted or unsubstituted 3- to 30-membered heteroarylamine group, wherein the heteroatom is selected from oxygen, nitrogen or sulfur.

[0013] As a further technical solution of the present invention, n and m are each independently 0 or 1, and n and m are not 0 at the same time.

[0014] As a further technical solution of the present invention, n and m are both 1.

[0015] As a further technical solution of the present invention, the L1 and L2 are the same or different from each other and are independently a linking bond; the substituted or unsubstituted C6-C 18 arylene; substituted or unsubstituted C3-C15 heteroarylene;

[0016] The R1-R3 are the same or different from each other and are independently hydrogen, deuterium, halogen, cyano, carboxyl, nitro, hydroxyl, amino; substituted or unsubstituted C1-C 15 Alkyl; substituted or unsubstituted C3-C 10 Cycloalkyl; substituted or unsubstituted 3-10 membered heterocycloalkyl, the heteroatom of which is selected from oxygen, nitrogen or sulfur; substituted or unsubstituted C6-C 20 Aryl; substituted or unsubstituted 3- to 10-membered heteroaryl, wherein the heteroatom is selected from oxygen, nitrogen or sulfur;

[0017] The Ar1 and Ar2 are the same as or different from each other, and are each independently oxazole, oxadiazole, triazole, triazine, imidazole, thiazole, pyridine, pyrazine, pyrimidine, triazine, benzimidazole, benzothiadiazole, quinoline, quinoxaline, cinnoline, naphthyridine, anthracene, diazaanthracene, naphthiadiazole, dibenzofuran, dibenzothiophene, benzodifuran, benzodithiophene, benzodioxazole, and benzodithiazole.

[0018] As a further technical solution of the present invention, said L1 and L2 are the same or different from each other, and said L1 and L2 are independently a linking bond, a substituted or unsubstituted C6-C 18 Arylene, substituted or unsubstituted C3-C 10 heteroarylene;

[0019] The R1-R3 are the same or different from each other and are independently hydrogen, deuterium, halogen, cyano, carboxyl, nitro, hydroxyl, amino; substituted or unsubstituted C1-C 10 Alkyl; substituted or unsubstituted C3-C 10 Cycloalkyl; substituted or unsubstituted 3-10 membered heterocycloalkyl, the heteroatom of which is selected from oxygen, nitrogen or sulfur; substituted or unsubstituted C6-C 18 Aryl; substituted or unsubstituted 3- to 10-membered heteroaryl, wherein the heteroatom is selected from oxygen, nitrogen or sulfur;

[0020] Ar1 and Ar2 are the same as or different from each other, and are independently oxazole, oxadiazole, triazole, triazine, imidazole, thiazole, pyridine, pyrimidine, triazine, quinoline, quinoxaline, or diazanthracene.

[0021] As a further technical solution of the present invention, the general formula 1 is one of the following formulas 1-1 to 1-9:

[0022]

[0023] Wherein, L1, L2, Ar1, Ar2, R1-R3 in Formulae 1-1 to 1-9 are as defined in Formula 1 above.

[0024] As a further technical solution of the present invention, the heteroatom-containing spirocyclic organic electroluminescent compound is one of the following structural formulas 1-248:

[0025]

[0026]

[0027]

[0028]

[0029]

[0030]

[0031]

[0032]

[0033]

[0034]

[0035]

[0036] A method for preparing a spirocyclic organic electroluminescent compound containing a heteroatom comprises the following steps:

[0037] Preparation of intermediate 1: Dissolve raw material 2 in THF, ventilate and cool, then slowly add n-BuLi. After the reaction, add raw material 1 under nitrogen protection, slowly increase the temperature and stir to prepare intermediate 1;

[0038] Preparation of intermediate 2: Add intermediate 1 to a reaction flask, add glacial acetic acid, and then add concentrated sulfuric acid dropwise after heating to prepare intermediate 2;

[0039] Preparation of a heteroatom-containing spirocyclic organic electroluminescent compound: adding intermediate 2 and raw material 3 and / or raw material 4 to a mixed solution of toluene, ethanol and water; adding a palladium catalyst and potassium carbonate under nitrogen protection after ventilation; stirring uniformly; and heating to react to prepare a heteroatom-containing spirocyclic organic electroluminescent compound;

[0040] Its synthetic route is as follows:

[0041]

[0042] wherein L1, L2, Ar1, Ar2, R1-R3 are as defined in Formula 1 above.

[0043] Preferably, the intermediate 1 is prepared by: dissolving the raw material 2 in THF, then ventilating 3 times, cooling to -78°C, slowly adding n-BuLi, reacting for 2 hours, adding the raw material 1 under nitrogen protection, slowly heating to 25°C, stirring for 10 hours, then slowly adding distilled water to the reaction solution to quench the reaction, and extracting the reaction solution with DCM; then drying the extracted organic layer with magnesium sulfate, and removing the solvent with a rotary evaporator; and precipitating the solid with DCM and PE (volume ratio 1:4) to obtain the intermediate 1;

[0044] The intermediate 2 is prepared by adding the intermediate 1 to a reaction flask, adding 10 times the volume of glacial acetic acid and heating to 80°C, slowly adding 1 times the volume of concentrated sulfuric acid dropwise, and the reaction is completed when the addition is complete, then adding distilled water 20 times the volume of concentrated sulfuric acid, and filtering and drying the solid to obtain the intermediate 2 after all the solids are precipitated;

[0045] The preparation of the heteroatom-containing spiro organic electroluminescent compound comprises the following steps: adding intermediate 2 and raw material 3 and / or raw material 4 to a mixed solution of toluene, ethanol and water, followed by venting three times, adding a palladium catalyst and potassium carbonate under nitrogen protection, stirring evenly, heating to 95° C., reacting for 10 hours, and then extracting the mixture with dichloromethane and water; then drying the extracted organic layer with sodium sulfate, and removing the solvent with a rotary evaporator; and purifying the remaining substance with column chromatography to obtain the heteroatom-containing spiro organic electroluminescent compound shown in Chemical Formula 1.

[0046] An electron transport layer comprises the above-mentioned spiro organic electroluminescent compound containing heteroatoms.

[0047] An organic electroluminescent device comprises the electron transport layer as described above.

[0048] Compared with the prior art, the present invention has the following beneficial effects: providing a spirocyclic organic electroluminescent compound containing heteroatoms, which has high electron injection and mobility rates, and good film-forming properties and thermal stability. When used in the electron transport layer of an organic electroluminescent device, it can significantly improve the electron transport efficiency from the electron transport layer to the light-emitting layer, thereby improving the luminous efficiency, while reducing the driving voltage and extending the service life of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 This is the hydrogen nuclear magnetic resonance spectrum of the heteroatom-containing spirocyclic organic electroluminescent compound prepared in Example 1;

[0050] Figure 2This is the hydrogen nuclear magnetic resonance spectrum of the heteroatom-containing spirocyclic organic electroluminescent compound prepared in Example 2;

[0051] Figure 3 This is the hydrogen nuclear magnetic resonance spectrum of the heteroatom-containing spirocyclic organic electroluminescent compound prepared in Example 3. DETAILED DESCRIPTION

[0052] A method for preparing a spirocyclic organic electroluminescent compound containing a heteroatom, the synthesis route of which is as follows:

[0053]

[0054] The preparation method specifically comprises the following steps:

[0055] Preparation of intermediate 1: Dissolve raw material 2 in THF, ventilate and cool, then slowly add n-BuLi. After the reaction, add raw material 1 under nitrogen protection, slowly increase the temperature and stir to prepare intermediate 1;

[0056] Preparation of intermediate 2: Add intermediate 1 to a reaction flask, add glacial acetic acid, and then add concentrated sulfuric acid dropwise after heating to prepare intermediate 2;

[0057] Preparation of heteroatom-containing spirocyclic organic electroluminescent compounds: intermediate 2 and raw material 3 are added to a mixed solution of toluene, ethanol and water. After ventilation, palladium catalyst and potassium carbonate are added under nitrogen protection. The mixture is stirred evenly and the temperature is increased to react to prepare a heteroatom-containing spirocyclic organic electroluminescent compound.

[0058] In the above synthetic route, n is 0, 1, 2 or 3, m is 0, 1, 2, 3 or 4, and n and m are not 0 at the same time;

[0059] L1 and L2 are the same or different and are independently a linking bond; substituted or unsubstituted C6-C 30 arylene; substituted or unsubstituted C3-C 30 heteroarylene;

[0060] R1, R2, and R3 are 0-4 substituents, R1-R3 are the same or different, and R1-R3 are independently hydrogen, deuterium, halogen, cyano, carboxyl, nitro, hydroxyl, amino, silicon, or borane; substituted or unsubstituted C1-C 30 Alkyl; substituted or unsubstituted C2-C 30 Alkenyl; substituted or unsubstituted C2-C 30 Alkynyl; substituted or unsubstituted C3-C 30 Cycloalkyl; substituted or unsubstituted 3-30 membered heterocycloalkyl, the heteroatom of which is selected from oxygen, nitrogen or sulfur; substituted or unsubstituted C6-C 30Aryl; substituted or unsubstituted 3-20 membered heteroaryl, whose heteroatom is selected from oxygen, nitrogen or sulfur; substituted or unsubstituted 3-25 membered heteroarylamino, whose heteroatom is selected from oxygen, nitrogen, sulfur; substituted or unsubstituted C6-C 60 arylamine group;

[0061] Ar1 and Ar2 are the same or different from each other, and Ar1 and Ar2 are independently substituted or unsubstituted C3-C 30 Cycloalkyl; substituted or unsubstituted 3-20 membered heterocycloalkyl, the heteroatom of which is selected from oxygen, nitrogen or sulfur; substituted or unsubstituted C6-C 30 aryl; a substituted or unsubstituted 3- to 30-membered heteroaryl group, wherein the heteroatom is selected from oxygen, nitrogen or sulfur; a substituted or unsubstituted 3- to 30-membered heteroarylamine group, wherein the heteroatom is selected from oxygen, nitrogen or sulfur.

[0062] The heteroatom-containing spirocyclic organic electroluminescent compound prepared by the above preparation method is selected from one of the following chemical formulas 1-248:

[0063]

[0064]

[0065]

[0066]

[0067]

[0068]

[0069]

[0070]

[0071]

[0072]

[0073]

[0074] Example 1

[0075] A method for preparing a spirocyclic organic electroluminescent compound containing a heteroatom, the synthesis route of which is as follows:

[0076]

[0077] The preparation method is specifically as follows:

[0078] Raw material 2 (44.6 mmol) and 100 ml of THF were added to the reaction vessel, and the temperature was lowered to -78°C after ventilating three times. 2.5 mol / L n-BuLi (17.8 ml, 44.6 mmol) was added under a nitrogen atmosphere and stirred for 2 h. Raw material 1 (37 mmol) was added and the temperature was raised to 25°C. The mixture was stirred for 10 h and the reaction was completed. Distilled water was then added to the reaction solution to quench the reaction, and the reaction solution was extracted with DCM. The extracted organic layer was then dried over magnesium sulfate, and the solvent was removed using a rotary evaporator. The solid was precipitated with DCM and PE (volume ratio 1:4) to obtain intermediate 1 (13.99 g, yield 75.3%).

[0079] Intermediate 1 (27.84 mmol) was added to a reaction flask, 240 ml of glacial acetic acid was added, the temperature was raised to 80°C, and 12 ml of concentrated sulfuric acid was added dropwise. The reaction was completed when the addition was complete. Then 240 ml of distilled water was added, and a solid precipitated. The solid was dried to obtain intermediate 2 (10.31 g, yield 76.5%).

[0080] Intermediate 2 (15 mmol) and raw material 3 (15 mmol) were added to a mixed solution of toluene, ethanol and water, followed by venting three times. Palladium catalyst and potassium carbonate were added under nitrogen protection, stirred evenly, heated to 95°C, reacted for 10 hours, and then the mixture was extracted with dichloromethane and water; the extracted organic layer was then dried over sodium sulfate, and the solvent was removed using a rotary evaporator; the remaining substance was purified by column chromatography to obtain compound 2 (5.84 g, yield 61.2%, MW: 636.76).

[0081] The obtained compound 2 was tested and analyzed, and the results were as follows:

[0082] HPLC purity: >99.5%;

[0083] Mass spectrometry test: theoretical value is 636.76; test value is 636.35;

[0084] Elemental analysis:

[0085] Calculated values: C, 86.77; H, 4.43; N, 8.80;

[0086] Found values: C, 85.86; H, 4.71; N, 8.98.

[0087] Example 2

[0088] A method for preparing a spirocyclic organic electroluminescent compound containing a heteroatom, the synthesis route of which is as follows:

[0089]

[0090] The preparation method is specifically as follows:

[0091] Raw material 2 (44.6 mmol) and 100 ml of THF were added to the reaction vessel, and the temperature was lowered to -78°C after ventilating three times. 2.5 mol / L n-BuLi (17.8 ml, 44.6 mmol) was added under a nitrogen atmosphere and stirred for 2 h. Raw material 1 (37 mmol) was added and the temperature was raised to 25°C. The mixture was stirred for 10 h, and the reaction was completed. Distilled water was then added to the reaction solution to quench the reaction, and the reaction solution was extracted with DCM. The extracted organic layer was then dried over magnesium sulfate, and the solvent was removed using a rotary evaporator. The solid was precipitated with DCM and PE (volume ratio 1:4) to obtain intermediate 1 (14.13 g, yield 76.1%).

[0092] Intermediate 1 (28.12 mmol) was added to a reaction flask, 240 ml of glacial acetic acid was added, the temperature was raised to 80°C, and 12 ml of concentrated sulfuric acid was added dropwise. The reaction was completed after the addition was completed. Then 240 ml of distilled water was added, and a solid precipitated. The solid was dried to obtain intermediate 2 (10.27, yield 75.41%).

[0093] Intermediate 2 (15 mmol) and raw material 3 (15 mmol) were added to a mixed solution of toluene, ethanol and water, followed by venting three times. Palladium catalyst and potassium carbonate were added under nitrogen protection, stirred evenly, heated to 95°C, reacted for 10 hours, and then the mixture was extracted with dichloromethane and water; the extracted organic layer was then dried over sodium sulfate, and the solvent was removed using a rotary evaporator; the remaining substance was purified by column chromatography to obtain compound 26 (6.69 g, yield 62.6%, MW: 712.86).

[0094] The obtained compound 26 was tested and analyzed, and the results were as follows:

[0095] HPLC purity: >99.5%;

[0096] Mass spectrometry test: theoretical value is 712.86; test value is 712.53;

[0097] Elemental analysis:

[0098] Calculated values: C, 87.62; H, 4.52; N, 7.86;

[0099] Found values: C, 87.03; H, 4.81; N, 7.99.

[0100] Example 3

[0101] A method for preparing a spirocyclic organic electroluminescent compound containing a heteroatom, the synthesis route of which is as follows:

[0102]

[0103] The preparation method is specifically as follows:

[0104] Raw material 2 (44.6 mmol) and 100 ml of THF were added to the reaction vessel, and the temperature was lowered to -78°C after ventilating three times. 2.5 mol / L n-BuLi (17.8 ml, 44.6 mmol) was added under a nitrogen atmosphere and stirred for 2 h. Raw material 1 (37 mmol) was added and the temperature was raised to 25°C. The mixture was stirred for 10 h, and the reaction was completed. Distilled water was then added to the reaction solution to quench the reaction, and the reaction solution was extracted with DCM. The extracted organic layer was then dried over magnesium sulfate, and the solvent was removed using a rotary evaporator. The solid was precipitated with DCM and PE (volume ratio 1:4) to obtain intermediate 1 (14.06 g, yield 75.69%).

[0105] Intermediate 1 (27.98 mmol) was added to a reaction flask, 240 ml of glacial acetic acid was added, the temperature was raised to 80°C, and 12 ml of concentrated sulfuric acid was added dropwise. The reaction was completed after the addition was completed. Then 240 ml of distilled water was added, and a solid precipitated. The solid was dried to obtain intermediate 2 (10.07 g, yield 74.38%).

[0106] Intermediate 2 (15 mmol) and raw material 3 (15 mmol) were added to a mixed solution of toluene, ethanol and water, followed by venting three times. Palladium catalyst and potassium carbonate were added under nitrogen protection, stirred evenly, heated to 95°C, reacted for 10 hours, and then extracted with dichloromethane and water; the extracted organic layer was then dried over sodium sulfate, and the solvent was removed using a rotary evaporator; the remaining substance was purified by column chromatography to obtain compound 66 (6.25 g, yield 62.1%, MW: 711.87).

[0107] The obtained compound 66 was tested and analyzed, and the results were as follows:

[0108] HPLC purity: >99.5%.

[0109] Mass spectrometry test: theoretical value is 711.87; test value is 711.53;

[0110] Elemental analysis:

[0111] Calculated values: C, 89.42; H, 4.67; N, 8.80;

[0112] Found values: C, 85.86; H, 4.71; N, 8.98.

[0113] Example 4

[0114] A method for preparing a spirocyclic organic electroluminescent compound containing a heteroatom, the synthesis route of which is as follows:

[0115]

[0116] The preparation method is specifically as follows:

[0117] Raw material 2 (44.6 mmol) and 100 ml of THF were added to the reaction vessel, and the temperature was lowered to -78°C after ventilating three times. 2.5 mol / L n-BuLi (17.8 ml, 44.6 mmol) was added under a nitrogen atmosphere and stirred for 2 h. Raw material 1 (37 mmol) was added and the temperature was raised to 25°C. The mixture was stirred for 10 h and the reaction was completed. Distilled water was then added to the reaction solution to quench the reaction, and the reaction solution was extracted with DCM. The extracted organic layer was then dried over magnesium sulfate, and the solvent was removed using a rotary evaporator. The solid was precipitated with DCM and PE (volume ratio 1:4) to obtain intermediate 1 (14.0 g, yield 75.4%).

[0118] Intermediate 1 (27.86 mmol) was added to a reaction flask, 240 ml of glacial acetic acid was added, the temperature was raised to 80°C, and 12 ml of concentrated sulfuric acid was added dropwise. The reaction was completed after the addition was completed. Then 240 ml of distilled water was added, and a solid precipitated. The solid was dried to obtain intermediate 2 (10.06 g, yield 74.58%).

[0119] Intermediate 2 (15 mmol) and raw material 3 (15 mmol) were added to a mixed solution of toluene, ethanol and water, followed by venting three times. Palladium catalyst and potassium carbonate were added under nitrogen protection, stirred evenly, heated to 95°C, reacted for 10 hours, and then the mixture was extracted with dichloromethane and water; the extracted organic layer was then dried over sodium sulfate, and the solvent was removed using a rotary evaporator; the remaining substance was purified by column chromatography to obtain compound 158 (7.01 g, yield 62.14%, MW: 752.92).

[0120] The obtained compound 158 was tested and analyzed, and the results were as follows:

[0121] HPLC purity: >99.4%;

[0122] Mass spectrometry test: theoretical value is 752.92; test value is 753.24;

[0123] Elemental analysis:

[0124] Calculated values: C, 87.74; H, 4.82; N, 7.44;

[0125] Found values: C, 87.61; H, 4.96; N, 7.67.

[0126] Example 5

[0127] A method for preparing a spirocyclic organic electroluminescent compound containing a heteroatom, the synthesis route of which is as follows:

[0128]

[0129] The preparation method is specifically as follows:

[0130] Raw material 2 (44.6 mmol) and 100 ml of THF were added to the reaction vessel, and the temperature was lowered to -78°C after ventilating three times. 2.5 mol / L n-BuLi (17.8 ml, 44.6 mmol) was added under a nitrogen atmosphere and stirred for 2 h. Raw material 1 (37 mmol) was added and the temperature was raised to 25°C. The mixture was stirred for 10 h, and the reaction was completed. Distilled water was then added to the reaction solution to quench the reaction, and the reaction solution was extracted with DCM. The extracted organic layer was then dried over magnesium sulfate, and the solvent was removed using a rotary evaporator. The solid was precipitated with DCM and PE (volume ratio 1:4) to obtain intermediate 1 (13.97 g, yield 75.24%).

[0131] Intermediate 1 (27.80 mmol) was added to a reaction flask, 240 ml of glacial acetic acid was added, the temperature was raised to 80°C, and 12 ml of concentrated sulfuric acid was added dropwise. The reaction was completed when the addition was complete. Then 240 ml of distilled water was added, and a solid precipitated. The solid was dried to obtain intermediate 2 (10.63 g, yield 76.2%).

[0132] Intermediate 2 (15 mmol) and raw material 3 (15 mmol) were added to a mixed solution of toluene, ethanol and water, followed by venting three times. Palladium catalyst and potassium carbonate were added under nitrogen protection, stirred evenly, heated to 95°C, reacted for 10 hours, and then extracted with dichloromethane and water; the extracted organic layer was then dried over sodium sulfate, and the solvent was removed using a rotary evaporator; the remaining substance was purified by column chromatography to obtain compound 178 (7.23 g, yield 61.3%, MW: 787.97).

[0133] The obtained compound 178 was tested and analyzed, and the results were as follows:

[0134] HPLC purity: >99.6%;

[0135] Mass spectrometry test: theoretical value is 787.97; test value is 787.73;

[0136] Elemental analysis:

[0137] Calculated values: C, 89.93; H, 4.73; N, 5.33;

[0138] Found values: C, 89.68; H, 4.89; N, 5.46.

[0139] The synthesis methods of other compounds are the same as those in the above examples and are not described in detail here. The mass spectra, molecular formulas and yields of other synthesis examples are shown in Table 1 below:

[0140] Table 1

[0141]

[0142]

[0143] Application Example 1

[0144] A method for preparing an organic electroluminescent device comprises the following steps:

[0145] a. ITO anode: An ITO (indium tin oxide)-Ag-ITO (indium tin oxide) glass substrate with a coating thickness of 150nm was washed twice in distilled water, ultrasonically washed for 30 minutes, and then repeatedly washed twice with distilled water and ultrasonically washed for 10 minutes. After washing, it was transferred to a spin dryer for drying, and finally baked in a vacuum oven at 220°C for 2 hours. After baking, it was cooled and used; using this substrate as the anode, an evaporation device process was carried out using an evaporation machine, and other functional layers were sequentially evaporated on it;

[0146] b. HIL (hole injection layer): The hole injection layer materials HT-1 and P-dopant were vacuum evaporated at a deposition rate of 97:3, and the thickness was 10 nm.

[0147] c. HTL (hole transport layer): At a deposition rate of 1%, 130 nm of HT-1 was vacuum-deposited on the hole injection layer as a hole transport layer;

[0148] d. EBL (electron blocking layer): The evaporation rate was 10 nm, and a 10 nm layer of EBL-1 electron blocking layer was vacuum evaporated on the hole transport layer.

[0149] e. EML (light-emitting layer): Then on the electron blocking layer, The host material (Host) and dopant material (Dopant) were vacuum-deposited to a thickness of 20 nm as the light-emitting layer. The chemical formulas of the Host and Dopant are shown below. The evaporation rate ratio of the Host and Dopant was 98:2.

[0150] f. HBL (hole blocking layer): At a deposition rate of , 5 nm of HB-1 was vacuum-deposited on the light-emitting layer as a hole-blocking layer;

[0151] g. ETL (Electron Transport Layer): The compound 2 provided in the above embodiment was vacuum-deposited on the hole blocking layer at a deposition rate of 30 nm as an electron transport layer;

[0152] h. EIL (electron injection layer): The evaporation rate is 1.0 nm, and a Yb film layer is evaporated to form an electron injection layer;

[0153] i. Cathode: 18 nm of magnesium and silver were evaporated at a deposition rate ratio of 1:9 to obtain an OLED device;

[0154] j. Light extraction layer: The evaporation rate is set at , and CPL-1 with a thickness of 70nm is vacuum evaporated on the cathode as a light extraction layer; then the evaporated substrate is encapsulated; first, the cleaned cover plate is coated with UV glue using a coating device, and then the coated cover plate is moved to the pressing section, and the evaporated substrate is placed on the upper end of the cover plate, and finally the substrate and cover plate are bonded by the bonding equipment, and the UV glue is light-cured at the same time.

[0155] The structural formula of the materials used in the above preparation method is as follows:

[0156]

[0157] Application Examples 2-50 Application Examples 2-50 refer to the method of Application Example 1 above, and replace the compound 2 used in Device Example 1 with compounds 3, 21, 23, 26, 28, 31, 34, 39, 41, 65, 66, 68, 82, 84, 95, 111, 112, 122, 127, 131, 135, 139, 143, 146, 158, 160, 162, 164, 166, 168, 169, 172, 175, 177, 178, 181, 183, 185, 188, 190, 191, 192, 198, 200, 201, 202, 204, 216, and 220 as electron transport layers to prepare corresponding organic electroluminescent devices.

[0158] Comparative Example 1-2

[0159] An organic electroluminescent device, the only difference between the preparation method of the organic electroluminescent device and Application Example 1 is that the organic electroluminescent device uses existing comparative compounds a and b to replace the electron transport layer (compound 2) in Application Example 1 for evaporation, to prepare comparative examples 1-2; wherein the chemical structures of comparative compounds a and b are:

[0160]

[0161] The driving voltage, luminous efficiency, BI value and lifespan of the organic electroluminescent devices obtained in the above application examples 1-50 and comparative examples 1-2 were characterized at a brightness of 1000 (nits). The test results are shown in Table 2 below:

[0162] Table 2 Test results (brightness value is 1000cd / m 2 )

[0163]

[0164]

[0165]

[0166] As can be seen from Table 2, the organic electroluminescent device prepared using the heteroatom-containing spirocyclic organic electroluminescent compound provided by the present invention as the electron transport layer has a lower starting voltage, and the luminous efficiency and life are significantly improved compared to the organic electroluminescent device prepared using compound a and compound b as the electron transport layer.

[0167] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims, not the foregoing description, and all variations within the meaning and range of equivalents of the claims are intended to be included therein. Any reference sign in a claim should not be construed as limiting the claim to which it relates.

[0168] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A spirocyclic organic electroluminescent compound containing a heteroatom, characterized in that: The heteroatom-containing spirocyclic organic electroluminescent compound is one of the following structural formulas:

2. An electron transport layer, characterized in that The electron transport layer comprises the heteroatom-containing spiro organic electroluminescent compound according to claim 1 .

3. An organic electroluminescent device, characterized in that: The organic electroluminescent device comprises the electron transport layer according to claim 2.

Images