Triptycencarbazole electron transport compound, preparation method thereof, organic electron transport complex and organic electroluminescent device

Abstract

The triptyclocinnoline compound provided by the patent application further incorporates triptycene on the cinnoline group, enhances the electron transport property, and matches the electron-withdrawing group and weak electron-donating group for regulating the LUMO energy level and electron injection performance of the compound, so that the triptyclocinnoline compound has good electron mobility and electron transport property, and further can form good n-doping effect with the n-dopant, and improve the electron transport performance of the compound and the n-dopant composition. By using the above two advantages, the organic electroluminescent device prepared by using the triptyclocinnoline compound as the electron transport material will have the beneficial effects of low driving voltage, high luminous efficiency and long device life, solve the problems of insufficient electron transport property of the electron transport material and unbalanced carriers of the device, and achieve the effect of improving the device life.

Description

TECHNICAL FIELD

[0001] The present patent application relates to the field of organic compounds, and more particularly to triptyclocinnoline electron transport compounds and a preparation method thereof, an organic electron transport complex and an organic electroluminescent device. BACKGROUND

[0002] Organic Light-emitting Diode (OLED) technology is an active light-emitting technology of an organic semiconductor thin film under the action of an applied electric field, which has many advantages such as flexibility, thinness, high luminance, low power consumption, etc. At present, it has been widely used in the fields of smart phones, televisions, wearable devices, vehicle-mounted displays, etc. Organic light-emitting materials are a key part of the OLED display technology industry chain, and are one of the technical barriers. It is of great significance to develop high-performance OLED materials.

[0003] However, the performance of the material determines the light-emitting performance of the device, and the transport characteristics of the carriers in the OLED device have an important influence on the driving voltage, luminous efficiency and device lifetime of the device. Through the research of organic transport layer materials, it is found that the hole mobility (10 -2 ~ 10 -3 cm / V·s) of the hole transport material is usually more than 10 times the electron mobility (10 -4 ~ 10 -6 cm / V·s) of the electron transport material. This leads to carrier imbalance in the device and will significantly increase the driving voltage of the device.

[0004] PATENT APPLICATION CONTENT

[0005] To overcome one of the problems existing in the prior art, the primary object of the present patent application is to provide a triptyclocinnoline electron transport compound. The triptyclocinnoline electron transport compound solves the problems of poor electron transport and material thermal stability caused by the intermolecular stacking of the existing electron transport material molecules for organic electroluminescent devices.

[0006] Another object of the present patent application is to provide a preparation method of the triptyclocinnoline electron transport compound described above.

[0007] Still another object of the present patent application is to provide an organic electron transport complex, which is formed by the triptyclocinnoline electron transport compound described above and an n-doped metal to form a complex with n-doping effect.

[0008] Another object of the present patent application is to provide an organic electroluminescent device comprising a substrate and, sequentially disposed on the substrate, an anode layer, an organic light-emitting functional layer, and a cathode layer, wherein the organic light-emitting functional layer comprises an electron transport layer, and the material of the electron transport layer comprises the organic electron transport complex described above.

[0009] The above objects of the present patent application are achieved by the following technical solutions.

[0010] A triptycene-cinnoline electron transport compound, which can be used as an organic electron transport material, has a molecular structure general formula as shown in (1) below:

[0011]

[0012] wherein X1 and X2 can represent carbon atoms and other groups, R1 represents a C6-C30 substituted or unsubstituted group containing an electron-withdrawing and weak electron-donating group, which can be further substituted or unsubstituted, and the substituent group is deuterium, -CN, a substituted or unsubstituted C6-C30 alkyl group, a substituted or unsubstituted C6-C30 aryl group, or a substituted or unsubstituted C6-C30 heteroaryl group.

[0013] Compared with the prior art, the present patent application has the following beneficial effects:

[0014] The triptycene-cinnoline electron transport compound of the present patent application further incorporates triptycene on the cinnoline group. The main function of the incorporation of triptycene is to prevent π-π stacking between molecules; at the same time, due to the special spatial configuration of triptycene, its conjugated system is further expanded, which expands the range of electron conjugation, which is conducive to enhancing the electron transport performance of the device itself. On the other hand, due to the connection of a carbon atom, the triptycene forms a stable molecular structure, which can obtain high molecular thermal stability. In addition, the further incorporation of electron-withdrawing substituents can regulate the electron transport property. For the above purposes, it is expected to improve the carrier (hole and electron) balance of the device, improve the luminous efficiency of the device, and reduce the efficiency roll-off of the device. By combining the above two advantages, the organic electroluminescent device prepared by using the triptycene-cinnoline compound of the present application as an electron transport material has the beneficial effects of low driving voltage, high luminous efficiency, and long device lifetime. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 The device structure schematic diagram of embodiments 20-32 of the present application is shown in the following figure:

[0016] Label explanation in the figure: 10, anode layer; 11, hole injection layer; 12, first hole transport layer; 13, second hole transport layer; 14, light emitting layer; 15, second electron transport layer; 16, first electron transport layer; 17, electron injection layer; 18, cathode layer figure. DETAILED DESCRIPTION

[0017] To make the objectives, technical solutions and advantages of the embodiments of the present disclosure clearer, the technical solutions of the embodiments of the present disclosure will be described clearly and completely below with reference to the drawings of the embodiments of the present disclosure. Obviously, the described embodiments are part of the embodiments of the present disclosure, rather than all the embodiments. Based on the described embodiments of the present disclosure, all other embodiments obtained by a person of ordinary skill in the art without any inventive effort fall within the protection scope of the present disclosure.

[0018] The present patent application provides a triptycene-cinnoline electron transport compound, which can be used for organic electron transport material, and the structural formula is as follows (1) shown in the molecular structure general formula:

[0019]

[0020] In the formula, X1 and X2 can represent carbon atoms and other groups, R1 represents C6-C30 substituted or unsubstituted groups containing electron-withdrawing and weak electron-donating groups, and the electron-withdrawing and weak electron-donating groups can be further substituted or unsubstituted, and the substituted groups are deuterium, -CN, substituted or unsubstituted C6-C30 alkyl, substituted or unsubstituted C6-C30 aryl, and substituted or unsubstituted C6-C30 heteroaryl.

[0021] In some preferred embodiments, the triptycene-cinnoline electron transport compound of the present patent application is one of the molecular structures shown in the following formulas (2)-(4):

[0022]

[0023] In the formula, X1 and X2 can be selected from hydrogen, deuterium atoms, methyl groups, benzene substituent groups, and R1 substituent groups selected from phenyl groups, biphenyl groups, benzocyan groups and derivatives thereof, pyridine and derivatives thereof, pyrimidine and derivatives thereof, triazine and derivatives thereof, phenanthroline and derivatives thereof, imidazole and derivatives thereof, and phosphorus oxy groups and derivatives thereof.

[0024] In some preferred embodiments, the triptycene-cinnoline electron transport compound of the present patent application is one of the molecular structures shown in the following formulas (5)-(7):

[0025]

[0026] wherein Y1and Y2, Y2and Y3may be further bonded to form a ring structure or not, Y1, Y2, Y3are not further bonded, Y1, Y2, Y3have the same meaning as R2; if further bonded, the bonded ring-forming atoms are selected from at least one of carbon atom, nitrogen atom, oxygen atom, sulfur atom; R2represents C6-C30 substituted or unsubstituted group containing electron-withdrawing and weak electron-donating group, the electron-withdrawing and weak electron-donating group can be further substituted or not, the substituted group is deuterium, -CN, substituted or unsubstituted C6-C30 alkyl, substituted or unsubstituted C6-C30 aryl; substituted or unsubstituted C6-C30 heteroaryl.

[0027] In some preferred embodiments, the R1group in the triptyclocinnoline electron transport compound of the present patent application has one of the following structures:

[0028]

[0029] wherein R3represents unsubstituted or substituted C6-C30 aryl, unsubstituted or substituted C2-C30 heteroaryl.

[0030] In some more preferred embodiments, the triptyclocinnoline electron transport compound of the present patent application is selected from any one of the structures shown in the following formula (5-1) to formula (5-96):

[0031]

[0032]

[0033]

[0034]

[0035]

[0036]

[0037]

[0038] The present patent application provides a preparation method of the compound of formula (2) in the above triptyclocinnoline electron transport compound, which comprises the following steps:

[0039] To the concentrated sulfuric acid solution of sodium nitrate, add tribromobenzene, keep the reaction temperature below 40℃, continue to stir the obtained mixture at 40℃ for 3 hours, then cool to 0℃, then neutralize with sodium hydroxide solution, filter the solution and wash the collected solid with water; after recrystallization from petroleum ether, the desired fine light yellow crystal intermediate P-2 is obtained;

[0040] In a drybox, nBuLi diluted in hexane was added slowly to anthracene P-3 and the intermediate P-2 in dry toluene at low temperature, the reaction mixture was stirred at room temperature overnight, then the reaction mixture was filtered, the removed solid was washed with dichloromethane and hexane, the solvent was removed under reduced pressure, the product was purified by silica gel column chromatography, and the yellow solid intermediate P-4 was collected;

[0041] In a Schlenk tube, the intermediate P-4, 2,5-dibromonitrobenzene and copper in DM solution were added, the mixture was stirred at 125°C for 1 hour, after cooling to room temperature, the brown residue was filtered off and washed with toluene, the filtrate was evaporated to dryness, the residue was purified by column chromatography using petroleum ether / dichloromethane to obtain the yellow solid product intermediate P-6;

[0042] Into a round bottom flask, the intermediate P-6 and iron powder were added, EtOH and HOAc were added and the reaction was continued for 3 hours, after cooling to room temperature, it was diluted and neutralized with concentrated hydrochloric acid, the ph was adjusted to 8 with K2CO3 aqueous solution, then the water layer was extracted with CH2Cl2 and the combined organic phase was washed with brine and dried with MgSO4, after evaporation of all volatiles, purification by flash column chromatography was performed to obtain the intermediate P-7;

[0043] Into an oven-dried round bottom flask, the intermediate P-7, tert-butyl nitrite and then solvent 2,2,2-trifluoroethanol were added, nitrogen was replaced, the reaction mixture was stirred at room temperature for 12-24 hours, after completion, the solid residue was removed by filtering through cotton, the mixture solution was concentrated using a rotary evaporator, and the intermediate P-8 was obtained by using silica gel flash column chromatography for purification;

[0044] Into a flask, a stirring rod was added, the intermediate P-8, phenylboronic acid pinacol ester, Pd(PPh3)4 and K2CO3 were added, THF and deoxygenated water were added, the mixture was reacted and stirred at 120°C and refluxed for 18 hours, the mixture was cooled to room temperature, the organic layer was extracted, and the organic layer was further purified by silica gel column chromatography to obtain the compound of formula (2).

[0045] In some preferred embodiments, the preparation method of the triptyclocinnoline electron transport compound in the present patent application is carried out under an inert atmosphere.

[0046] The present patent application also provides an organic electron transport complex, which is a complex of the above-mentioned triptyclocinnoline electron transport compound and an n-doped metal to form an n-doped complex.

[0047] In some preferred embodiments, the n-doped metal is selected from one or more of lithium, copper, silver, gold, magnesium, barium, ytterbium, cesium and their oxides or carbonates, lithium 8-hydroxyquinolineate, sodium 8-hydroxyquinolineate, ZnO, and CsN3.

[0048] In some preferred embodiments, the mass percentage of the doping concentration of the n-doped metal is 0.1-30%.

[0049] This patent application provides an organic electroluminescent device, including a substrate and an anode layer, an organic light-emitting functional layer and a cathode layer sequentially disposed on the substrate, wherein the organic light-emitting functional layer includes an electron transport layer, characterized in that the material of the electron transport layer includes the aforementioned organic electron transport complex.

[0050] To address the issues of poor electron transport and thermal stability caused by intermolecular stacking in existing electron transport materials used in organic electroluminescent devices, the patent applicant has developed a series of electron transport materials with high electron mobility. These materials typically incorporate triazine and its derivatives, pyridine and its derivatives, phenanthroline and benzo[a]nephrine derivatives to lower the LUMO energy level of the electron transport material, enabling smooth electron injection into the device. To further expand the conjugated system while reducing intermolecular stacking, tripterene is introduced into the electron-deficient group. Based on the unique spatial configuration of tripterene, its molecular structure allows for an extended conjugated system, expanding the range of electron conjugation to a certain extent. Consequently, its electronic conductivity and optical properties are optimized to some degree. Besides excellent electron transport performance, good thermal stability is also a key factor in improving device performance. Triptterene, due to sharing a single carbon atom, forms a stable molecular structure. This structure gives tripterene high molecular stability and chemical inertness, providing resistance to environmental conditions such as light, heat, and oxidation. This stability provides a reliable potential application basis for tripterene in materials science and chemical synthesis.

[0051] The preparation method of the triterpenoid electron transport compound (I) will be described in detail below.

[0052] Example 1: Preparation of Tripterone-1 electron transport compound 5-1

[0053] The preparation method of the triterpenoid electron transport compound 5-1 in this patent application involves a chemical reaction equation as follows:

[0054]

[0055] The specific preparation method described above includes the following steps:

[0056] To a solution of sodium nitrate (4 g, 48 mmol) in concentrated sulfuric acid (110 mL) was added tribromobenzene (10 g, 32 mmol) over 20 minutes under nitrogen atmosphere, keeping the reaction temperature below 40°C. The resulting mixture was stirred at 40°C for 3 hours, then cooled to 0°C before being neutralized with a sodium hydroxide solution (2 M). The solution was filtered and the collected solid was washed with water. The desired fine light yellow crystals P-2 were obtained after recrystallization from petroleum ether, yield 8.4 g, 72.7% yield.

[0057] To a solution of nBuLi (2.5 mol / L in hexane, 14.36 mL, 35.9 mmol) diluted in hexane (50 mL) was slowly added to anthracene (P-3) (4 g, 22.4 mmol) and P-2 (12.4 g, 4 mmol) in dry toluene (100 mL) at 0°C under nitrogen atmosphere. The reaction mixture was stirred overnight at room temperature, the reaction mixture was filtered. The removed solid was washed with dichloromethane and hexane (50 mL + 50 mL). The solvent was removed under reduced pressure. The product was purified by column chromatography on silica gel (hexane:CH2Cl2= 1 :0 to 1 :1). The yellow solid P-4 was collected, yield 2.26, 53.7% yield.

[0058] In a 200 mL Schlenk tube, P-4 (3.83 g, 10 mmol), P-5 (2.83 g, 11 mmol) and copper (1.28 g, 20.0 mmol) were added in DMF (27 mL). The mixture was stirred at 125°C for 1 hour under nitrogen atmosphere. After cooling to room temperature, the brown residue was filtered off and washed with 10 mL of toluene, the filtrate was evaporated to dryness. The residue was purified by column chromatography on silica gel using petroleum ether / dichloromethane (5:1 v / v) as eluent. The yellow solid product P-6 was obtained, yield 3.86, 77.3% yield.

[0059] To a round bottom flask was added P-6 (10.0 g, 22.08 mmol) and iron powder (6.17 g, 55.85 mmol) under nitrogen atmosphere. EtOH (50 mL) and HOAc (50 mL) were added and the reaction was left for 3 hours. After cooling to room temperature, the mixture was diluted with water (100 ml) and neutralized with concentrated hydrochloric acid. K2CO3 aqueous solution was added to reach ph ~ 8. The aqueous layer was extracted with CH2Cl2(3 x 100 ml) and the combined organic phases were washed with brine and dried over MgSO4. After evaporation of all volatiles, P-7 was obtained by flash column chromatography (SiO2, CH2Cl2 / MeOH 100% / 0%→ 90% / 10%), yield 9.47 g, 91.4% yield.

[0060] Into an oven-dried round bottom flask, under nitrogen atmosphere, was added intermediate P-7 (4.39, 10 mmol), tert-butyl nitrite (tBuONO, 3.09 g, 30 mmol), followed by solvent 2,2,2-trifluoroethanol (TFE, 0.1 M, 20 ml). The reaction mixture was stirred at room temperature for 12-24 hours, after completion, the solid residue was removed by filtration through cotton, the mixture solution was concentrated using a rotary evaporator, and purified using silica gel flash column chromatography with hexane and ethyl acetate as eluent to obtain intermediate P-8, yield 3.13 g, 72.6% yield.

[0061] Into a 100 mL flask, under nitrogen atmosphere, was added a stir bar, P-8 (4.35 g, 10 mmol), P-9 (2.28 g, 12 mmol), Pd(PPh3)4(346.8 mg, 0.3 mmol, ) and K2CO3(4.14 g, 30 mmol). THF (50 ml) and deoxygenated water (25 ml) were added, the mixture was reacted at 120 °C and stirred at reflux for 18 hours, the mixture was cooled to room temperature. Dichloromethane extraction obtained the organic layer, which was further purified by silica gel column chromatography to obtain yellow solid 5-1, yield 3.18, 71.4% yield

[0062] Example 2 Preparation of triptyclocinnoline electron transport compound 5-4

[0063] The preparation method of triptyclocinnoline electron transport compound 5-4 of the present patent application involves chemical reaction equation as shown below:

[0064]

[0065] The above specific preparation method includes the following steps:

[0066] Into a 100 mL flask, under nitrogen atmosphere, was added a stir bar, P-8 (4.35 g, 10 mmol), P-9 (3.89 g, 12 mmol), Pd(PPh3)4(346.8 mg, 0.3 mmol, ) and K2CO3(4.14 g, 30 mmol). THF (50 ml) and deoxygenated water (25 ml) were added, the mixture was reacted at 80 °C and stirred at reflux for 18 hours, the mixture was cooled to room temperature. Dichloromethane extraction obtained the organic layer, which was further purified by silica gel column chromatography to obtain yellow solid 5-4, yield 4.36 g, 74.4% yield.

[0067] Example 3 Preparation of triptyclocinnoline electron transport compound 5-19

[0068] The preparation method of triptyclocinnoline electron transport compound 5-19 of the present patent application involves chemical reaction equation as shown below:

[0069]

[0070] The above specific preparation method comprises the following steps:

[0071] Under nitrogen protection, intermediate P-12 (6.28 g, 20 mmol, 1 eq), bis(pinacolato)diborane (7.62 g, 30 mmol, 1.5 eq), potassium acetate (KOAc, 5.88 g, 60 mmol, 3 eq), Pd(dppf)Cl2(438.6 mg, 0.6 mmol, 0.03 eq) and 120 ml of dioxane were placed in a round-bottom flask. The mixture was heated at 120°C under nitrogen for 48 hours. After cooling to room temperature, the mixture was washed with 50 ml of water three times and extracted with dichloromethane. The organic solution was dried with Mg2SO4, and then the solvent was evaporated. The residue was purified by column chromatography with a petroleum ether / dichloromethane mixture to obtain white solid intermediate P-11, with a yield of 6.96 g and a yield of 72.6%.

[0072] Under nitrogen protection, P-11 (3.72 g, 10.00 mmol, 1.00 Eq), P-12 (3.73 g, 10.30 mmol, 1.10 Eq), K2CO3(4.14 g, 30 mmol, 3 Eq) and Pd(PPh3)4(0.346 g, 0.3 mmol, 0.03 Eq). THF (50 ml) and deoxygenated water (25 ml) were added, the mixture was reacted and stirred at reflux at 80°C for 18 hours, and the mixture was cooled to room temperature. Dichloromethane extraction obtained the organic layer, and the organic layer was further purified by silica gel column chromatography to obtain yellow solid 5-19, with a yield of 4.53 g and a yield of 74.4%.

[0073] Example 4 Preparation of triptyclocinnoline electron transport compound 5-20

[0074] The preparation method of the triptyclocinnoline electron transport compound 5-20 of the present patent application involves chemical reaction equations represented as follows:

[0075]

[0076] The above specific preparation method comprises the following steps:

[0077] A dry two necked flask was charged with P-14 (2.06 g, 10 mmol), isoamylnitrite (1.24 g, 1.1 mmol) under nitrogen atmosphere, then 30 mL of dichloromethane was added as solvent, vacuum-nitrogen cycle was repeated three times, the reaction was stirred at 60 °C, P-13 (1.5 g, 1.1 mmol) in 20 mL of acetone was added dropwise, the reaction was stirred for 4 hours, the solution was distilled, maleic anhydride (1.4 g, 1.5 mmol) was added, then 40 mL of xylene was added, the reaction was stirred at 150 °C for 24 hours, cooled to room temperature, partitioned, spin dried, dried, purified by silica gel column to get solid intermediate P-15, yield 1.70 g, yield 42.5%.

[0078] A solution of P-15 (4.06 g, 10 mmol), P-5 (2.83 g, 11 mmol) and copper (1.28 g, 20.0 mmol) in DMF (27 mL) was added to a 200 mL Schlenk tube under nitrogen atmosphere. The mixture was stirred at 125 °C for 1 hour. After cooling to room temperature, the brownish residue was filtered off and washed with 10 mL of toluene, the filtrate was evaporated to dryness. The residue was purified by column chromatography on silica gel using petroleum ether / dichloromethane (5:1) as eluent. The yellow solid product P-16 was obtained in a yield of 3.86, 77.3%

[0079] A round bottom flask was charged with P-16 (11.0 g, 22.08 mmol) and iron powder (6.17 g, 55.85 mmol) under nitrogen atmosphere. EtOH (50 mL) and HOAc (50 mL) were added continuously for 3 hours. After cooling to room temperature, the mixture was diluted with water (100 ml) and neutralized with concentrated hydrochloric acid. K2CO3(aq, (ph ~ 8). The aqueous layer was extracted with CH2Cl2(3 x 100 ml) and the combined organic phases were washed with brine and dried over MgSO4. After evaporation of all volatiles, P-17 was obtained by flash column chromatography (SiO2, CH2Cl2 / MeOH 100% / 0%→90% / 10%) in a yield of 7.97 g, 85.6%.

[0080] An oven-dried round bottom flask was charged with intermediate P-17 (4.69, 10 mmol), tert-butyl nitrite (tBuONO, 3.09 g, 30 mmol) under nitrogen atmosphere, then 2,2,2-trifluoroethanol (TFE, 0.1 M, 20 ml) was added as solvent. The reaction mixture was stirred at room temperature for 12-24 hours, after completion, the solid residue was removed by filtration through cotton, the solution of the mixture was concentrated using a rotary evaporator, and purified using flash column chromatography on silica gel using hexane and ethyl acetate as eluents to obtain intermediate P-18 in a yield of 3.53 g, 75.6%.

[0081] Under nitrogen atmosphere, intermediate P-18 (9.34 g, 10 mmol), bis(pinacolato)diboron (7.62 g, 30 mmol), potassium acetate (KOAc, 5.88 g, 60 mmol), Pd(dppf)Cl2(438.6 mg, 0.6 mmol) and 120 ml of dioxane were placed in a round bottom flask. The mixture was heated at 120 °C under nitrogen for 48 hours. After cooling to room temperature, the mixture was washed with 50 ml of water three times and extracted with dichloromethane. The organic solution was dried with Mg2SO4, then the solvent was evaporated. The residue was purified by column chromatography with petroleum ether / dichloromethane mixture to obtain intermediate P-19 as a white solid, yield 6.91 g, 68.3 %.

[0082] Under nitrogen atmosphere, in a 100 mL flask, a stirring bar was added, P-19 (4.62 g, 10 mmol), P-12 (4.18 g, 12 mmol), Pd(PPh3)4(346.8 mg, 0.3 mmol,) and K2CO3(4.14 g, 30 mmol) were added. THF (50 ml) and deoxygenated water (25 ml) were added, the mixture was reacted at 120 °C and stirred to reflux for 18 hours, the mixture was cooled to room temperature. Dichloromethane extraction obtained the organic layer, the organic layer was further purified by silica gel column chromatography to obtain 5-20 as a yellow solid, yield 4.84, 71.9 %.

[0083] Example 5 Preparation of triptyclocinnoline electron transport compound 5-21

[0084] The preparation method of triptyclocinnoline electron transport compound 5-21 of the present patent application involves chemical reaction equation as shown below:

[0085]

[0086] The above specific preparation method comprises the following steps:

[0087] Under nitrogen protection, P-20 (3.30 g, 10 mmol), isoamyl nitrite (1.24 g, 1.1 mmol) were placed in a dry two-necked flask, then 30 mL of dichloromethane was added as a solution, vacuumed and filled with nitrogen for three times, stirred at 60 °C, added P-13 (1.5 g, 1.1 mmol) in 20 mL of acetone solution, reacted for 4 hours, distilled the solution, added maleic anhydride (1.4 g, 1.5 mmol), then added 40 mL of dimethylbenzene, stirred at 150 °C for 24 hours, cooled to room temperature, separated, spin-dried, dried, and purified by silica gel column to obtain solid intermediate P-21, yield 2.21 g, yield 41.6 %.

[0088] A solution of P-21 (5.30 g, 10 mmol), P-5 (2.83 g, 11 mmol) and copper (1.28 g, 20.0 mmol) in DMF (27 mL) was added to a 200 mL Schlenk tube under nitrogen atmosphere and the mixture was stirred at 125 °C for 1 h. After cooling to room temperature, the brown residue was filtered off and washed with 10 mL of toluene, the filtrate was evaporated to dryness. The residue was purified by column chromatography on silica gel using petroleum ether / dichloromethane (5:1) as eluent v / v). The yellow solid product P-22 was obtained in a yield of 4.36 g, 66.8%

[0089] To an oven-dried round bottom flask under nitrogen atmosphere was added P-22 (14.3 g, 22.08 mmol) and iron powder (6.17 g, 55.85 mmol). EtOH (50 mL) and HOAc (50 mL) were added and the mixture was stirred for 3 h. After cooling to room temperature, the mixture was diluted with water (100 mL) and neutralized with concentrated hydrochloric acid. K2CO3 (aq. (ph ~ 8). The aqueous layer was extracted with CH2Cl2 (3 x 100 mL) and the combined organic phases were washed with brine and dried over MgSO4. After evaporation of all volatiles, flash column chromatography (SiO2, CH2Cl2 / MeOH 100% / 0%→ 90% / 10%) was used to obtain P-23 in a yield of 9.61 g, 81.4%.

[0090] To an oven-dried round bottom flask under nitrogen atmosphere was added intermediate P-23 (5.94 g, 10 mmol), tert-butyl nitrite (tBuONO, 3.09 g, 30 mmol) and then solvent 2,2,2-trifluoroethanol (TFE, 0.1 M, 20 mL). The reaction mixture was stirred at room temperature for 12-24 h, after completion, the solid residue was removed by filtration through cotton, the mixture solution was concentrated using a rotary evaporator and purified using flash column chromatography on silica gel using hexane and ethyl acetate as eluents to obtain intermediate P-24 in a yield of 4.18 g, 71.3%.

[0091] Under nitrogen atmosphere, intermediate P-24 (5.86 g, 10 mmol), bis(pinacolato)diboron (7.62 g, 30 mmol), potassium acetate (KOAc, 5.88 g, 60 mmol), Pd(dppf)Cl2(438.6 mg, 0.6 mmol) and 120 ml of dioxane were placed in a round bottom flask. The mixture was heated at 120 °C under nitrogen for 48 hours. After cooling to room temperature, the mixture was washed with 50 ml of water three times and extracted with dichloromethane. The organic solution was dried with Mg2SO4, then the solvent was evaporated. The residue was purified by column chromatography with petroleum ether / dichloromethane mixture to obtain intermediate P-25 as a white solid, yield 3.24 g, 59.1 %.

[0092] Under nitrogen atmosphere, intermediate P-24 (5.86 g, 10 mmol), bis(pinacolato)diboron (7.62 g, 30 mmol), potassium acetate (KOAc, 5.88 g, 60 mmol), Pd(dppf)Cl2(438.6 mg, 0.6 mmol) and 120 ml of dioxane were placed in a round bottom flask. The mixture was heated at 120 °C under nitrogen for 48 hours. After cooling to room temperature, the mixture was washed with 50 ml of water three times and extracted with dichloromethane. The organic solution was dried with Mg2SO4, then the solvent was evaporated. The residue was purified by column chromatography with petroleum ether / dichloromethane mixture to obtain intermediate P-25 as a white solid, yield 3.24 g, 59.1 %.

[0093] Example 6 Preparation of triptyclocinnoline electron transport compound 5-39

[0094] The preparation method of triptyclocinnoline electron transport compound 5-39 of the present patent application involves chemical reaction equations as shown below:

[0095]

[0096] The above specific preparation method includes the following steps:

[0097] Under nitrogen atmosphere, intermediate P-24 (5.86 g, 10 mmol), bis(pinacolato)diboron (7.62 g, 30 mmol), potassium acetate (KOAc, 5.88 g, 60 mmol), Pd(dppf)Cl2(438.6 mg, 0.6 mmol) and 120 ml of dioxane were placed in a round bottom flask. The mixture was heated at 120 °C under nitrogen for 48 hours. After cooling to room temperature, the mixture was washed with 50 ml of water three times and extracted with dichloromethane. The organic solution was dried with Mg2SO4, then the solvent was evaporated. The residue was purified by column chromatography with petroleum ether / dichloromethane mixture to obtain intermediate P-25 as a white solid, yield 3.24 g, 59.1 %.

[0098] A round bottom flask was charged with intermediate P-27 (13.27 g, 10 mmol), bis(pinacolato)diboron (7.62 g, 30 mmol), potassium acetate (KOAc, 5.88 g, 60 mmol), Pd(dppf)Cl2(438.6 mg, 0.6 mmol) and 120 mL of dioxane under nitrogen atmosphere. The mixture was heated at 120 °C for 48 hours under nitrogen. After cooling to room temperature, the mixture was washed with 50 mL of water three times and extracted with dichloromethane. The organic solution was dried over Mg2SO4and then the solvent was evaporated. The residue was purified by column chromatography using a mixture of petroleum ether / dichloromethane to obtain intermediate P-28 as a white solid with a yield of 10.3 g, 72.5% of yield.

[0099] A 100 mL flask was charged with stirring bar, P-25 (7.10 g, 10 mmol), P-29 (2.64 g, 12 mmol), Pd(PPh3)4(346.8 mg, 0.3 mmol,) and K2CO3(4.14 g, 30 mmol) under nitrogen atmosphere. THF (50 mL) and deoxygenated water (25 mL) were added and the mixture was heated at 120 °C and stirred at reflux for 18 hours. The mixture was cooled to room temperature. The organic layer was extracted with dichloromethane and further purified by column chromatography on silica gel to obtain 5-39 as a yellow solid with a yield of 4.69 g, 61.7% of yield.

[0100] Example 7 Preparation of triptyclocinnoline electron transport compound 5-49

[0101] The method for preparing triptyclocinnoline electron transport compound 5-49 according to the present patent application involves the chemical reaction equation shown below:

[0102]

[0103] The above specific preparation method comprises the following steps:

[0104] A 200 mL Schlenk tube was charged with a solution of P-4 (3.83 g, 10 mmol), P-30 (2.83 g, 11 mmol) and copper (1.28 g, 20.0 mmol) in DMF (27 mL) under nitrogen atmosphere. The mixture was stirred at 125 °C for 1 hour. After cooling to room temperature, the brown residue was filtered off and washed with 10 mL of toluene and the filtrate was evaporated to dryness. The residue was purified by column chromatography on silica gel using petroleum ether / dichloromethane (5:1) as eluent v / v). The product P-31 was obtained as a yellow solid with a yield of 3.76 g, 76.3% of yield

[0105] Into a round bottom flask under nitrogen atmosphere was added P-31 (10.0 g, 22.08 mmol) and iron powder (6.17 g, 55.85 mmol). EtOH (50 ml) and HOAc (50 ml) were added for 3 hours. After cooling to room temperature, the mixture was diluted with water (100 ml) and neutralized with concentrated hydrochloric acid. K2CO3 (aq. (ph ~ 8). The aqueous layer was extracted with CH2Cl2 (3 x 100 ml) and the combined organic phases were washed with brine and dried over MgSO4. After evaporation of all volatiles, flash column chromatography (SiO2, CH2Cl2 / MeOH 100% / 0%→ 90% / 10%) was used to obtain P-32, yield 8.97 g, 89.4% yield.

[0106] Into an oven-dried round bottom flask under nitrogen protection was added intermediate P-32 (4.39, 10 mmol), tert-butyl nitrite (tBuONO, 3.09 g, 30 mmol) and then solvent 2,2,2-trifluoroethanol (TFE, 0.1 M, 20 ml). After replacing the nitrogen, the reaction mixture was stirred at room temperature for 12-24 hours. After completion, the solid residue was removed by filtration through cotton, the mixture solution was concentrated using a rotary evaporator and purified using flash column chromatography on silica gel using hexane and ethyl acetate as eluents to obtain intermediate P-33, yield 2.85 g, 67.6% yield.

[0107] Into a 100 mL flask under nitrogen atmosphere was added a stirring bar, P-33 (4.35 g, 10 mmol), P-10 (2.28 g, 12 mmol), Pd(PPh3)4 (346.8 mg, 0.3 mmol,) and K2CO3 (4.14 g, 30 mmol). THF (50 ml) and deoxygenated water (25 ml) were added, the mixture was reacted at 120 °C and stirred at reflux for 18 hours, the mixture was cooled to room temperature. The organic layer was obtained by dichloromethane extraction, the organic layer was further purified by column chromatography on silica gel to obtain yellow solid 5-49, yield 4.67, 79.4% yield.

[0108] Example 8 Preparation of triptyclocinnoline electron transport compound 5-67

[0109] The method for preparing triptyclocinnoline electron transport compound 5-67 of the present patent application involves chemical reaction equations represented as follows:

[0110]

[0111] The above specific preparation method comprises the following steps:

[0112] A round bottom flask was charged with intermediate P-33 (8.47 g, 20 mmol), bis(pinacolato)diboron (7.62 g, 30 mmol), potassium acetate (KOAc, 5.88 g, 60 mmol), Pd(dppf)Cl2(438.6 mg, 0.6 mmol) and 120 mL of dioxane under nitrogen atmosphere. The mixture was heated at 120 °C for 48 hours under nitrogen. After cooling to room temperature, the mixture was washed with 50 mL of water three times and extracted with dichloromethane. The organic solution was dried over Mg2SO4and then the solvent was evaporated. The residue was purified by column chromatography using a mixture of petroleum ether / dichloromethane to obtain intermediate P-34 as a white solid with a yield of 7.2 g, 75.0 % of yield.

[0113] A 100 mL flask was charged with a stirring bar, P-34 (4.80 g, 10 mmol), P-29 (2.64 g, 12 mmol), Pd(PPh3)4(346.8 mg, 0.3 mmol,) and K2CO3(4.14 g, 30 mmol) under nitrogen atmosphere. THF (50 mL) and deoxygenated water (25 mL) were added and the mixture was heated at 120 °C and stirred at reflux for 18 hours. The mixture was cooled to room temperature. The organic layer was extracted with dichloromethane and further purified by column chromatography on silica gel to obtain 5-67 as a yellow solid with a yield of 3.16 g, 59.6 % of yield.

[0114] Example 9 Preparation of triazolocinnoline electron transport compound 5-68

[0115] The method for preparing triazolocinnoline electron transport compound 5-68 according to the present patent application involves the chemical reaction equation shown below:

[0116]

[0117] The above specific preparation method comprises the following steps:

[0118] A 200 mL Schlenk tube was charged with a stirring bar, a solution of P-15 (4.05 g, 10 mmol), P-30 (2.83 g, 11 mmol) and copper (1.28 g, 20.0 mmol) in DMF (27 mL) under nitrogen atmosphere. The mixture was stirred at 125 °C for 1 hour. After cooling to room temperature, the brown residue was filtered off and washed with 10 mL of toluene and the filtrate was evaporated to dryness. The residue was purified by column chromatography on silica gel using petroleum ether / dichloromethane (5:1) as eluent v / v). The product P-35 was obtained as a yellow solid with a yield of 3.54 g, 67.3 % of yield.

[0119] To a round bottom flask under nitrogen atmosphere was added P-35 (11.0 g, 22.08 mmol) and iron powder (6.17 g, 55.85 mmol). EtOH (50 ml) and HOAc (50 ml) were added for 3 hours. After cooling to room temperature, the mixture was diluted with water (100 ml) and neutralized with concentrated hydrochloric acid. K2CO3 (aq. (ph ~ 8). The aqueous layer was extracted with CH2Cl2 (3 x 100 ml) and the combined organic phases were washed with brine and dried over MgSO4. After evaporation of all volatiles, flash column chromatography (SiO2, CH2Cl2 / MeOH 100% / 0%→ 90% / 10%) was used to obtain P-36, yield 8.37 g, 82.4% yield.

[0120] To an oven-dried round bottom flask under nitrogen atmosphere was added intermediate P-36 (4.66, 10 mmol), tert-butyl nitrite (tBuONO, 3.09 g, 30 mmol) and then solvent 2,2,2-trifluoroethanol (TFE, 0.1 M, 20 ml). The reaction mixture was stirred at room temperature for 12-24 hours under nitrogen atmosphere. After completion, the solid residue was removed by filtration through cotton wool and the mixture solution was concentrated using a rotary evaporator and purified using flash column chromatography on silica gel using hexane and ethyl acetate as eluents to obtain intermediate P-37, yield 2.85 g, 67.6% yield.

[0121] Under nitrogen atmosphere, intermediate P-37 (9.22 g, 20 mmol), bis(pinacolato)diboron (7.62 g, 30 mmol), potassium acetate (KOAC, 5.88 g, 60 mmol), Pd(dppf)Cl2 (438.6 mg, 0.6 mmol) and 120 ml of dioxane were placed in a round bottom flask. The mixture was heated at 120 °C under nitrogen for 48 hours. After cooling to room temperature, the mixture was washed three times with 50 ml of water and extracted with dichloromethane. The organic solution was dried over Mg2SO4 and then the solvent was evaporated. The residue was purified by column chromatography with a mixture of petroleum ether / dichloromethane to obtain intermediate P-38 as a white solid, yield 6.54 g, 64.8% yield.

[0122] Into a 100 mL flask, under nitrogen atmosphere, was added a stir bar, P-38 (4.35 g, 10 mmol), P-29 (2.63 g, 12 mmol), Pd(PPh3)4(346.8 mg, 0.3 mmol, 0.3 mmol), and K2CO3(4.14 g, 30 mmol). THF (50 ml) and deoxygenated water (25 ml) were added, and the mixture was heated to 120 °C and stirred at reflux for 18 h. The mixture was cooled to room temperature. The organic layer was extracted with dichloromethane, and the organic layer was further purified by silica gel column chromatography to obtain yellow solid 5-68 in 3.64, 64.8% yield.

[0123] Characterization and performance test

[0124] Elemental analysis and mass spectrometry experiments were performed on the compounds prepared in Examples 1-9, and the elemental analysis and molecular weight thereof are shown in Table 1. The glass transition temperature and decomposition temperature of compounds 5-1, 5-4, 5-49, 5-67, comparative compound 1, and comparative compound 4, and the electron mobility of the compounds are shown in Tables 2 and 3.

[0125] From Table 1, we can see that after modification of the cinnoline triazolopyrene, although the molecular weight increases, in combination with Table 2, the modification of triazolopyrene makes the electron transport material more stable than the comparison of cinnoline derivative structure and o-phenanthroline derivative structure of comparative compounds 1 and 2 without triazolopyrene modification. The increase in stability is not necessarily related to the molecular weight, and may also be related to the molecular configuration of triazolopyrene.

[0126]

[0127]

[0128] Table 1 Elemental analysis, molecular weight results of compounds

[0129]

[0130] Table 2 Glass transition temperature and decomposition temperature results of compounds

[0131] The molecular structure formulas of comparative compound 1 and comparative compound 2 in the present patent application are as follows:

[0132]

[0133] By comparing the thermal stability results of compounds 5-1, 5-4, and comparative compounds 1 and 2 in Table 2, it can be seen that the triptene-modified boralin compounds of this application have significantly higher glass transition temperatures and thermal decomposition temperatures compared to benzene- and methyl-modified boralin electronic compounds and structurally similar phenanthroline derivatives. At the same time, the thermal stability of the above-mentioned triptene-boralin compounds is also better than that of phenanthroline compounds. The improved thermal stability of the material is beneficial to improving the lifespan of organic electroluminescent devices.

[0134] application

[0135] Next, the organic electroluminescent device of this application will be further described.

[0136] This application provides an organic electroluminescent device, such as... Figure 1 As shown, it includes a substrate and, sequentially disposed on the substrate, an anode layer 10, a hole injection layer 11, a first hole transport layer 12, a second hole transport layer 13, a light-emitting layer 14, a second electron transport layer 15, a first electron transport layer 16, an electron injection layer 17, and a cathode layer 18. The first electron transport layer 16 comprises the borynthotridecene derivative compound described in this application.

[0137] Anode layer 10

[0138] The anode layer 10 of the organic electroluminescent device primarily functions to inject holes into the hole injection layer 11, hole transport layer, or light-emitting layer 14. Preferably, an anode layer material with a work function of 4.5 eV or higher is used. The anode layer material is preferably selected from indium tin oxide (ITO), tin oxide (NESA), indium gallium zinc oxide (IGZO), silver, etc. The anode layer 10 can be formed into a thin film by thermal evaporation, sputtering, or other methods. Preferably, the light transmittance of the visible area of ​​the anode layer 10 is greater than 80%. Furthermore, the sheet resistance of the anode layer 10 is preferably 500 Ω / cm. -1 The film thickness is preferably selected in the range of 10-200 nm.

[0139] Cathode layer 18

[0140] The primary function of the cathode layer 18 in the organic electroluminescent device is to inject electrons into the electron injection layer 17, electron transport layer, or light-emitting layer 14. A material with a low work function is preferred. The cathode layer material is not particularly limited, but is preferably selected from aluminum, magnesium, silver, magnesium-silver alloys, magnesium-aluminum alloys, or aluminum-lithium alloys. Similarly, the cathode layer 18 can also be formed into a thin film using methods such as thermal evaporation or sputtering. The film thickness of the cathode layer 18 is preferably selected within the range of 10-200 nm. Additionally, light can be extracted from the cathode side as needed.

[0141] Electron injection layer 17

[0142] In the organic electroluminescent device, an electron injection layer 17 is preferably provided in the interface region of the cathode layer 18 and the electron transport layer or the light-emitting layer 14. The electron injection layer 17 mainly functions to facilitate injection of electrons from the cathode layer 18 into the electron transport layer or the light-emitting layer 14, thereby improving the luminance and the device lifetime of the organic electroluminescent device. Here, the electron injection layer material refers to a material having a work function of 3.8 eV or less, and the electron injection layer material can be preferably at least one selected from lithium, sodium, potassium, rubidium, cesium, magnesium, calcium, gold, silver, copper, iron, nickel, platinum, palladium, ruthenium, ytterbium, molybdenum trioxide, vanadium pentoxide, tungsten trioxide, cesium fluoride, cesium carbonate, lithium fluoride, lithium carbonate, lithium 8-hydroxyquinolinate (Liq), and the like. The electron injection layer 17 can be formed by a thermal evaporation method to form an electron injection layer film, and the evaporation rate is preferably 0.01 to 1 A / second. The film thickness of the thus-produced electron injection layer 17 is preferably selected within a range of 0.1 to 15 nm.

[0143] Second electron transport layer 15

[0144] The electron transport layer of the organic electroluminescent device is an organic layer formed between the light-emitting layer 14 and the cathode layer 18 (or the electron injection layer 17), and mainly functions to transport electrons from the first electron transport layer 16 to the light-emitting layer 14.

[0145] As the electron transport layer material for the second electron transport layer 15, an aromatic heterocyclic compound containing one or more heteroatoms in the molecule is preferably used, and a nitrogen-containing ring derivative is particularly preferably used. In addition, as the nitrogen-containing ring derivative, an aromatic ring having a nitrogen-containing six-membered ring or five-membered ring skeleton, or a fused aromatic ring compound having a nitrogen-containing six-membered ring or five-membered ring skeleton is preferably used.

[0146] The second electron transport layer material in the organic electroluminescent device of the present application is preferably selected from the compounds represented by formula (ET-13) to formula (ET-16) and formula (ET-45) to formula (ET-52), but is not limited to the following structures:

[0147]

[0148]

[0149] The film thickness of the second electron transport layer 15 is preferably 1 to 30 nm.

[0150] Hole transport layer

[0151] The hole transport layer of the organic electroluminescent device is an organic layer formed between the light emitting layer 14 and the anode layer 10 (or the hole injection layer 11), and its main function is to transport holes from the anode layer to the light emitting layer 14. The hole transport layer can be composed of one layer of organic layer material, which is defined as the first hole transport layer 12; or it can be composed of two layers of organic layer material, with the organic layer close to the anode layer 10 defined as the first hole transport layer 12, and the organic layer close to the light emitting layer 14 defined as the second hole transport layer 13.

[0152] The hole transport layer of the organic electroluminescent device of the present application can preferably be selected from aromatic amine compounds, preferably from compounds represented by formulae (HT-1) to (HT-63), but is not limited to the following structures:

[0153]

[0154]

[0155]

[0156]

[0157]

[0158]

[0159]

[0160] The film thickness of the hole transport layer is not particularly limited, and is preferably 20 to 200 nm. Among them, when the hole transport layer of the organic electroluminescent device is composed of the first hole transport layer, the film thickness of the first hole transport layer is preferably 20 to 200 nm; when the hole transport layer of the organic electroluminescent device is composed of the first hole transport layer and the second hole transport layer, the film thickness of the first hole transport layer is preferably 19 to 150 nm, and the film thickness of the second hole transport layer is preferably 1 to 50 nm.

[0161] The hole injection layer 11

[0162] The present application relates to an organic electroluminescent device, preferably, a hole injection layer 11 is provided at the interface region of the anode layer 10 and the hole transport layer (or the light emitting layer 14). The hole injection layer 11 mainly functions to promote the injection of holes from the anode layer 10 to the hole transport layer or the light emitting layer 14, thereby reducing the driving voltage of the organic electroluminescent device and improving the luminance and the lifetime of the device. Here, the hole injection layer material is formed by combining a deep LUMO level acceptor type p-dopant with a hole transport material, and the hole transport material is preferably selected from the compounds represented by the formulae (HT-1) to (HT-63). As specific examples, the p-dopant can be preferably selected from one of HI-1 to HI-20, and the film thickness of the hole injection layer 11 is not particularly limited, and is preferably selected within the range of 1 to 50 nm.

[0163] wherein the structural formulae of HI-1 to HI-20 are as follows:

[0164]

[0165]

[0166] Examples 20 to 32

[0167] Examples 20 to 32 The following are specific examples of the preparation of an organic electroluminescent device using the compounds of the present application, and the specific device preparation process and the device performance test experiment operations are as follows:

[0168] A 30 mm x 30 mm x 0.7 mm glass substrate with an ITO transparent electrode (anode layer, the film thickness of ITO is set to 160 nm) was sequentially subjected to ultrasonic cleaning in a washing liquid (1 time), acetone (1 time), ultrapure water (2 times), and isopropyl alcohol (1 time), and the ultrasonic cleaning time was 10 minutes for each step. The cleaned ITO glass substrate was placed in an oven at 80°C for 3 hours. The washing liquid is used to clean the dirt and oil adhered to the surface of the glass substrate with an ITO transparent electrode, which is a commercially available product and will not be described here.

[0169] The ITO transparent electrode glass substrate after baking was subjected to vacuum plasma cleaning treatment for 10 minutes.

[0170] The above glass substrate after plasma treatment was installed on the substrate holder of a vacuum evaporation device, and compound HI-6 and the first compound HT-10 were co-evaporated on the side where the ITO transparent electrode was formed, and the doping concentration of compound HI-6 was 3 mass%, and a hole injection layer 11 with a film thickness of 10 nm was formed.

[0171] Compound HT-10 was evaporated on the hole injection layer to form a first hole transport layer 12 with a film thickness of 30 nm.

[0172] Then, a second hole transport layer 13 having a thickness of 10 nm is formed by evaporating compound HT-64 on the first hole transport layer.

[0173] Then, a light-emitting layer 14 having a thickness of 40 nm is formed by co-evaporating a second compound GH (host material) and a first compound GD (dopant material) on the second hole transport layer, the dopant concentration of compound GD being 3% by mass ratio, and GH and GD having the following structures:

[0174]

[0175] Then, a second electron transport layer 15 having a thickness of 10 nm is formed by evaporating ET-46 on the light-emitting layer.

[0176] Then, a first electron transport layer 16 having a thickness of 30 nm is formed by co-evaporating a second compound, a cinnoline and triptycene compound, and a first compound, n-dopant, on the second electron transport layer.

[0177]

[0178]

[0179] Table 3. First electron transport layer material composition of Examples 20-32

[0180] Then, an electron injection layer 17 having a thickness of 2 nm is formed by evaporating Yb on the first electron transport layer.

[0181] Then, a cathode layer 18 having a thickness of 100 nm is formed by evaporating metal Al on the electron injection layer, thereby obtaining an organic electroluminescent device.

[0182] Comparative Examples 40-45

[0183] The organic electroluminescent devices prepared in Comparative Examples 40-45 are the same as those of Examples 20-32, except that the first electron transport layer is prepared by co-evaporating (Comparative Compound 1, 2 or 3) as a second compound and a first compound, and the second compound and the first compound combination and mass ratio are shown in Table 4.

[0184]

[0185]

[0186] Table 4. First electron transport layer material composition of Comparative Examples 40-45

[0187] Comparative Compound 1, 2 or 3 has the following structure, respectively:

[0188]

[0189] Performance evaluation of organic electroluminescent device

[0190] The performance of the organic electroluminescent devices prepared in Examples 20-32 and Comparative Examples 40-45 of the present application was measured using a spectroradiometric luminance meter CS-2000 (Konica Minolta) and a digital source meter 2420 (Keithley) to measure the external quantum efficiency (unit %) of the prepared organic electroluminescent devices at 10 mA / cm 2 The external quantum efficiency (unit %) at a current density of 10 mA / cm2, the driving voltage (unit V), and the T95 (time required for luminance decay to 95% of the initial luminance) lifetime (unit hour) of the organic electroluminescent devices prepared in Examples 20-32 and Comparative Examples 40-45 of the present application are shown in Table 5.

[0191] The performance results of the organic electroluminescent devices prepared in Examples 20-32 and Comparative Examples 40-45 of the present application are shown in Table 5.

[0192]

[0193]

[0194] The performance results of the organic electroluminescent devices prepared in Examples 20-32 and Comparative Examples 40-45 of the present application are shown in Table 5.

[0195] From the comparison of the device performance results of Examples 20-32 and Comparative Examples 40-45 in Table 5, it can be seen that the organic electroluminescent devices prepared from the triptyclocinnoline compounds of the present application have a maximum external quantum efficiency of 24.9% and a maximum device lifetime of 492 h; compared to the organic electroluminescent devices prepared from Comparative Compounds 1-3, which have a maximum external quantum efficiency of 22.1% and a maximum device lifetime of 358 h.

[0196] This is because the triptycene of the compounds of the present application effectively prevents π-π stacking between molecules; at the same time, on the one hand, the triptycene is connected by sharing one carbon atom to form a stable molecular structure. This structure makes it possible to obtain higher molecular thermal stability and good electron transportability, making it easier for electrons from the cathode of the device to be injected into the light-emitting layer, thereby reducing the driving voltage of the device; on the other hand, the triptycene unit has higher chemical stability, which improves the device lifetime.

[0197] Further, comparing the device performance results of examples 20-32 and comparative examples 40-45 in table 5, it can be seen that when the triptyclocinnoline compound is further combined with n-dopant to form an electron transport composition, the driving voltage of the device is further reduced (the lowest driving voltage is 3.2 V), and the n-doping performance of the triptyclocinnoline compound is better than that of the phenanthrolin compound, so the driving voltage of the device is lower. Furthermore, the complex formed by the triptyclocinnoline compound and the n-dopant further improves the stability of the electron transport material, thereby improving the device lifetime.

[0198] By comparing the glass transition temperature and decomposition temperature of examples 5-1, 5-4, 5-49, and 5-67 in table 2, it can be seen that the triptyclocinnoline compound with an electron-withdrawing group at the para position has better thermal stability than other materials with electron-withdrawing groups at other positions. Further comparing the device performance results of examples 20, 21, 26, and 27, the improvement in thermal stability of the material will simultaneously improve the device lifetime.

[0199] In summary, the triptyclocinnoline compound of the present application has better electron transport properties and good chemical stability as an electron transport material, and the prepared organic electroluminescent device achieves low driving voltage, high efficiency, and long device lifetime.

[0200] In addition to the compounds prepared in examples 1-9, other triptyclocinnoline electron transport compounds in the present patent application have similar structures to the prepared compounds, and all belong to further incorporating triptycene on the cinnoline group. Therefore, by using similar preparation methods and the same characterization and testing methods, the electron transport properties are enhanced, and electron-withdrawing groups are matched to regulate the LUMO level and electron injection performance of the compound, so that the triptyclocinnoline electron transport compound has good electron mobility and electron transport properties, and can further form good n-doping with n-dopant to improve the electron transport performance of the compound and n-dopant composition.

[0201] The triptyclocinnoline compound provided in the present patent application further incorporates triptycene on the cinnoline group, enhances the electron transport properties, and matches electron-withdrawing groups and weak electron-donating groups to regulate the LUMO level and electron injection performance of the compound, so that the triptyclocinnoline compound has good electron mobility and electron transport properties, and can further form good n-doping with n-dopant to improve the electron transport performance of the compound and n-dopant composition. By using the above two advantages, the organic electroluminescent device prepared by using the triptyclocinnoline compound of the present application as an electron transport material will have the beneficial effects of low driving voltage, high luminous efficiency, and long device lifetime, solve the problems of insufficient electron transport properties of the electron transport material and unbalanced carriers of the device, and achieve the effect of improving the device lifetime.

[0202] In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "exemplary embodiment", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present patent application. In the present specification, the exemplary expressions of the above terms do not necessarily refer to the same embodiment or example. Also, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in an appropriate manner.

[0203] Although several embodiments of the present patent application have been shown and described, it is understood that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present patent application, the scope of which is defined by the claims and their equivalents.

Claims

1. A triterpenoid electron transport compound, characterized in that, The tripteneroline electron transport compound can be used in organic electron transport materials, and its structural formula is selected from the following structural formulas: 、 、 ； 5-1 5-4 5-19 、 、 ； 5-20 5-21 5-39 、 、 ； 5-49 5-67 5-68。 2. The preparation method of the triterpenoid electron transport compound according to claim 1, characterized in that, Includes the following steps: Tribromobenzene P-1 was added to a concentrated sulfuric acid solution of sodium nitrate, and the reaction temperature was kept below 40°C. The resulting mixture was stirred at 40°C for 3 hours and then cooled to 0°C. The mixture was then neutralized with sodium hydroxide solution, the solution was filtered, and the collected solid was washed with water. The desired fine light yellow crystalline intermediate P-2 was obtained by recrystallization from petroleum ether. Under low temperature conditions, nBuLi diluted in hexane was slowly added to anthracene P-3 and intermediate P-2 in a dry toluene solution. The reaction mixture was stirred overnight at room temperature, then the reaction mixture was filtered, and the solids removed were washed with dichloromethane and hexane. The solvent was removed under reduced pressure, and the product was purified by silica gel column chromatography to collect the yellow solid intermediate P-4. Intermediate P-4, 2,5-dibromonitrobenzene P-5 and copper were added to a Schlenk tube in DMF solution. The mixture was stirred at 125°C for 1 hour. After cooling to room temperature, the brown residue was filtered out and washed with toluene. The filtrate was evaporated to dryness. The residue was purified by column chromatography using petroleum ether / dichloromethane to give the yellow solid intermediate P-6. The intermediate P-6 and iron powder were added to a round-bottom flask, and EtOH and HOAc were added and the reaction was continued for 3 hours. After cooling to room temperature, the mixture was diluted and neutralized with concentrated hydrochloric acid. The pH was adjusted to 8 with K2CO3 aqueous solution. The aqueous layer was then extracted with CH2Cl2 and the combined organic phase, washed with brine and dried with MgSO4. After evaporating all volatiles, the intermediate P-7 was purified by rapid column chromatography. Add intermediate P-7 and tert-butyl nitrite to a dried round-bottom flask, then add solvent 2,2,2-trifluoroethanol, replace with nitrogen, stir the reaction mixture at room temperature for 12-24 hours, remove solid residue by cotton filtration, concentrate the mixture solution using a rotary evaporator, and purify it using silica gel rapid column chromatography to obtain intermediate P-8. Add a stir bar to a flask, add the intermediate P-8, pinacol phenylboronic acid ester P-9, Pd(PPh3)4 and K2CO3, THF and deoxygenated water, react at 120°C and reflux the mixture for 18 hours with stirring. Cool the mixture to room temperature, extract to obtain an organic layer, and further purify the organic layer by silica gel column chromatography to obtain compound of formula 5-1. The chemical reaction equations involved in the above preparation method are shown below: 。 3. The method for preparing the triterpenoid electron transport compound according to claim 2, characterized in that, All preparation methods are carried out under an inert atmosphere.

4. An organic electron transport complex, characterized in that, The organic electron transport complex is a complex formed by the triterpenoid electron transport compound of claim 1 and an n-doped metal, which has an n-doping effect.

5. The organic electron transport complex according to claim 4, characterized in that, The n-doped metal is selected from one or more of lithium, copper, silver, gold, magnesium, barium, ytterbium, cesium and their oxides or carbonates, lithium 8-hydroxyquinolineate, sodium 8-hydroxyquinolineate, ZnO, and CsN3.

6. The organic electron transport complex according to claim 5, characterized in that, The mass percentage of the doping concentration of the n-doped metal is 0.1-30%.

7. An organic electroluminescent device, comprising a substrate and an anode layer, an organic light-emitting functional layer, and a cathode layer sequentially disposed on the substrate, wherein the organic light-emitting functional layer includes an electron transport layer, characterized in that, The material of the electron transport layer includes the organic electron transport complex according to any one of claims 4-6.

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