Bisindole compound containing fused ring aryl as well as preparation method and application of bisindole compound

Abstract

The invention relates to the related technical field of organic electroluminescent materials, in particular to a condensed ring aryl-containing bisindole compound, which is prepared by the following steps: synthesizing an intermediate M1, and further synthesizing the intermediate M1 prepared in the step a to obtain the condensed ring aryl-containing bisindole compound, the condensed ring aryl-containing bisindole compound is applied to the organic electroluminescent device, the organic electroluminescent device comprises an anode, a cathode and an organic thin film layer arranged between the anode and the cathode, and the organic thin film layer comprises a light-emitting layer. The light-emitting layer is prepared from the following components: a bis-indole compound containing a fused ring aryl group; the invention can provide the condensed ring aryl-containing bisindole compound which is suitable for being used as a main body material of a light-emitting layer of an organic electroluminescent device and is high in current efficiency and long in service life, and the preparation method and the application of the condensed ring aryl-containing bisindole compound.

Description

Technical Field

[0001] The invention belongs to the technical field related to organic electroluminescent materials, and specifically relates to a bisindole compound containing a condensed ring aromatic group, and a preparation method and application thereof. Background Art

[0002] Organic electroluminescence (EL) refers to a luminescence phenomenon in which organic materials directly convert electrical energy into light energy under the action of an electric field. Organic electroluminescent devices are spontaneous light-emitting devices that use the above principle. They have the characteristics of self-luminescence, bright colors, thin thickness, light weight, fast response speed, wide viewing angle, low driving voltage, tolerance to harsh natural conditions, and can be made into flexible panels. They have gradually developed into the most advantageous technology in the field of new generation flat panel displays.

[0003] The structure of an organic electroluminescent device (OLED) is specifically: an anode, a cathode, and an organic thin film layer between the two. In order to improve the efficiency and stability of the organic electroluminescent device, the organic material layer 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), an electron injection layer (EIL), an electron blocking layer, etc. In order to improve the performance of organic electroluminescent devices, various new OLED materials have also been developed. However, its various performances need to be improved, especially in terms of current efficiency and lifespan. In order to meet people's higher requirements for OLED devices, the field is in urgent need of developing more types of OLED materials with higher performance. Summary of the invention

[0004] The object of the present invention is to provide a bisindole compound containing a condensed ring aromatic group which is suitable for being used as a main material of a light-emitting layer of an organic electroluminescent device, has high current efficiency and long life, and a preparation method and application thereof.

[0005] To achieve the above object, the present invention provides the following technical solution: a bisindole compound containing a condensed ring aromatic group, whose specific structural chemical formula I is:

[0006]

[0007] Wherein Ar1 and Ar2 are each independently selected from any one of C6 to C40 aromatic groups, phenyl, biphenyl, 9,9-dimethylfluorenyl, naphthyl, triphenylene, fluoranthenyl, phenanthryl, dibenzofuranyl, dibenzothienyl, naphthodibenzofuranyl, and naphthodibenzothienyl; and the hydrogen atom is substituted by at least one of -D, -F, -CN, C6 to C20 aromatic groups, C6 to C20 heteroaryl groups, C1 to C20 alkyl groups, and C1 to C20 alkoxy groups.

[0008] As a further improvement of the present invention, the C6 to C40 aromatic group is selected from any one of phenyl, biphenyl, terphenyl, naphthyl, anthracenyl, phenanthryl, fluorenyl, benzofluorenyl, dibenzofluorenyl, naphthfluoroenyl, pyrene, perylenyl, spirofluorenyl, triphenylene, fluoranthenyl, hydrogenated benzanthryl, indenofluorenyl, benzoindenofluorenyl, dibenzoindenofluorenyl, naphthfluoroenyl, and benzonaphthofluorenyl.

[0009] As a further improvement of the present invention, the hydrogen atoms in the bisindole compounds containing condensed ring aromatic groups are replaced by at least one of phenyl, naphthyl, biphenyl, fluorenyl, dibenzofuran, dibenzothiophene, methyl, ethyl, propyl, butyl, cyclohexyl, adamantyl, methoxy, ethoxy, propoxy and butoxy groups.

[0010] As a further improvement of the present invention, the bisindole compound containing a condensed aromatic ring is replaced by any one of the following twenty compounds, including:

[0011]

[0012] A method for preparing a bisindole compound containing a condensed aromatic ring comprises the following steps: Step a: first synthesizing an intermediate M1, and the specific synthesis process is as follows:

[0013]

[0014] Step b: Further synthesis operation is performed using the intermediate M1 obtained in step a to obtain

[0015] The specific synthesis process of the bisindole compounds containing condensed aromatic rings is as follows:

[0016]

[0017] As a further improvement of the present invention, the preparation step of the intermediate M1 in step a comprises:

[0018] Step a1: under nitrogen protection, add dry toluene, 2-chloro-10,10-methyl-9,11-diphenyl-10,11-dihydro-9H-benzo[6,7]cycloheptane[2,1-b:4,5-b']diindole, bipyraclostrobin, PdCl2(PPh3), and KOAc into a three-necked flask, heat to reflux, cool to room temperature after reaction, and then add water to dilute;

[0019] Step a2: Then, the organic layer was washed with water until neutral, dried with magnesium sulfate, filtered to remove the magnesium sulfate, concentrated to dryness, separated by silica gel column chromatography, and eluted with a solvent of petroleum ether: ethyl acetate = 50:1 by volume to obtain intermediate M1;

[0020] Step a3: Finally, the intermediate M1 is subjected to mass spectrometry to measure the mass-to-charge ratio.

[0021] As a further improvement of the present invention, the further synthesis operation of step b, the specific preparation steps include:

[0022] Step b1: under nitrogen protection, add dioxane and water in a three-necked flask in sequence, and then add intermediate M1, 2-chloro-4,6-diphenyl-1,3,5-triazine, sodium carbonate and tetrakistriphenylphosphine palladium; slowly heat up to reflux reaction, cool to room temperature, add water and toluene for separation, wash the organic layer with water, and dry it with magnesium sulfate;

[0023] Step b2: After removing the desiccant, the mixture is concentrated to dryness and crystallized from toluene to obtain a bisindole compound containing a condensed ring aromatic group;

[0024] Step b3: Finally, the bisindole compounds containing condensed ring aromatic groups are subjected to mass spectrometry detection to measure the mass-to-charge ratio.

[0025] As a further improvement of the present invention, the 2-chloro-4,6-diphenyl-1,3,5-triazine is replaced by a triazine compound.

[0026] An application of a bisindole compound containing a condensed aromatic ring, wherein the bisindole compound containing a condensed aromatic ring is applied to an organic electroluminescent device, wherein the organic electroluminescent device comprises an anode, a cathode and an organic thin film layer arranged between the anode and the cathode, wherein the organic thin film layer comprises a light-emitting layer, and the light-emitting layer comprises the bisindole compound containing a condensed aromatic ring.

[0027] As a further improvement of the present invention, the organic electroluminescent device is a phosphorescent organic electroluminescent device.

[0028] The luminescent layer in the present invention includes a luminescent layer main material and a doping material, wherein the doping material is also called a dye or a phosphorescent luminescent material. The luminescent layer main material can be a single compound or a mixture of two or more compounds.

[0029] The light-emitting layer includes a phosphorescent light-emitting layer, and the phosphorescent light-emitting layer includes a green phosphorescent light-emitting layer, a red phosphorescent light-emitting layer, and a yellow phosphorescent light-emitting layer.

[0030] The volume percentage of the main material in the phosphorescent layer is 60% to 99.9% (for example, it can be 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98% or 99.9%, etc.), preferably 70% to 99.5%, and more preferably 85% to 95%.

[0031] In the present invention, the doping material of the light-emitting layer may be a phosphorescent material, which is also called a triplet light-emitting material, and refers to the light emitted by a substance from a triplet excited state. The specific selection of the phosphorescent material in the present invention is not particularly limited, and the doping materials of the light-emitting layer commonly used in the art are applicable, including but not limited to: compounds having structures shown in formula D1 and D2:

[0032]

[0033] R1-R8, R11-R18 and R101-R103 are each independently selected from -H (hydrogen), -D (deuterium), -F (fluorine), -Cl (chlorine), -Br (bromine), -I (iodine), hydroxyl, cyano, nitro, amino, amidine, hydrazine, hydrazone, carboxylic acid, carboxylate, sulfonic acid, sulfonate, phosphoric acid, phosphate, -SF5, substituted or unsubstituted C1-C60 alkyl, substituted or unsubstituted C2-C60 alkenyl , any one of a substituted or unsubstituted C2-C60 alkynyl group, a substituted or unsubstituted C1-C60 alkoxy group, a substituted or unsubstituted C1-C10 heterocycloalkyl group, a substituted or unsubstituted C1-C10 heterocycloalkenyl group, a substituted or unsubstituted C6-C60 aryl group, a substituted or unsubstituted C6-C60 aryloxy group, a substituted or unsubstituted C6-C60 arylthio group, a substituted or unsubstituted monovalent non-aromatic fused polycyclic group, and a substituted or unsubstituted monovalent non-aromatic fused heteropolycyclic group.

[0034] And R1 to R4 may be connected with adjacent R1 to R4 to form a substituted or unsubstituted condensed ring, for example, to form a substituted or unsubstituted naphthyl, fluorene, dibenzothiophene, dibenzofuran, indenopyridine, benzofluoropyridine or benzothienopyridine ring.

[0035] Preferably, the compound is selected from any one of the following compounds:

[0036]

[0037] In the present invention, the organic thin film layer includes a hole layer, and the hole layer includes a hole injection layer, a hole transport layer and an electron blocking layer.

[0038] The hole injection layer material includes a P-type dopant. The P-type dopant refers to a dopant that coexists with the hole injection layer material in the OLED device and can oxidize the hole injection layer material, thereby acting as an electron acceptor and promoting the movement of holes in the hole injection layer to the anode. In the present invention, the difference between the absolute value of the LUMO of the P-type dopant and the absolute value of the HOMO of the hole layer material is greater than -0.2V, preferably greater than -0.1eV, more preferably greater than 0eV, more preferably greater than 0.1eV, and more preferably greater than 0.2eV. The electron transport layer may include at least one of a hole blocking layer, an electron transport layer, an electron buffer layer, and an electron injection layer. The hole blocking layer, the electron transport layer, the electron buffer layer, and the electron injection layer may be a single layer or a plurality of layers in which two or more layers are stacked, respectively. The electron buffer layer may be a multilayer to control the injection of electrons and improve the interface characteristics between the light-emitting layer and the electron injection layer, wherein each multilayer may use two compounds simultaneously. The hole blocking layer or the electron transport layer may also be a multilayer, wherein each multilayer may use a variety of compounds.

[0039] In the present invention, the material of the cathode is a metal with a low work function (e.g., alkaline earth metal, alkali metal, main group metal or lanthanide element (e.g., Ca, Ba, Mg, Al, In, Mg, Yb, Sm, etc.)), a metal alloy composed of multiple metals (alloy composed of alkali metal or alkaline earth metal and silver, such as an alloy composed of magnesium and silver) or a multilayer structure. If the cathode material is a multilayer structure, in addition to the metals mentioned above, other metals with relatively high work functions, such as Ag or Al, can also be used. In this case, a combination of the metals is usually used, such as Ca / Ag, Mg / Ag or Ba / Ag.

[0040] It is also possible to introduce a thin intermediate layer of a material with a high dielectric constant between the metal cathode and the organic semiconductor to form a multilayer structure; the material with a high dielectric constant can also be called an electron injection material, and fluorides of alkali metals or alkaline earth metals, and corresponding oxides or carbonates (such as LiF, Li2O, BaF2, MgO, NaF, CsF, Cs2CO3, etc.) or lithium quinoline (LiQ) can be selected.

[0041] Compared with the prior art, the beneficial effects of the present invention are as follows: the technical solution designs the structure of the bisindole compound to make it suitable as the main material of the light-emitting layer of the organic electroluminescent device, and the organic electroluminescent device prepared thereby has higher current efficiency and longer service life. DETAILED DESCRIPTION

[0042] The following will be combined with the scheme in the embodiment of the present invention to clearly and completely describe the technical scheme in the embodiment of the present invention. The described embodiment is only a part of the embodiment of the present invention, not all the embodiments. Based on the embodiment of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0043] Preparation Example 1:

[0044] This preparation example provides an intermediate M1 and a synthesis method thereof, and the synthesis method is as follows:

[0045]

[0046] Under nitrogen protection, 200 mL of dry toluene, 2-chloro-10,10-methyl-9,11-diphenyl-10,11-dihydro-9H-benzo[6,7]cycloheptane[2,1-b:4,5-b']diindole (5.35 g), bipyraclostrobin (5.8 g), PdCl2(PPh3) (0.05 g), and KOAc (0.1 g) were added to a 500 mL three-necked flask, and the mixture was heated to reflux. After reacting for 18 h, the mixture was cooled to room temperature and separated by adding water. The organic layer was then washed with water until neutral, dried over magnesium sulfate, filtered to remove magnesium sulfate, concentrated to dryness, separated by silica gel column chromatography, and eluted with a solvent of petroleum ether:ethyl acetate = 50:1 (volume ratio) to obtain 4 g of intermediate M1.

[0047] The intermediate M1 was subjected to mass spectrometry detection: the mass-to-charge ratio (m / z) was measured to be 626.31.

[0048] Synthesis Example 1:

[0049] This synthesis example provides a bisindole compound P1 and a synthesis method thereof, and the synthesis method is as follows:

[0050]

[0051] Under nitrogen protection, 200 ml of dioxane and 60 ml of water were added to a 500 ml three-necked flask in sequence, and then intermediate M1 (6.2 g), 2-chloro-4,6-diphenyl-1,3,5-triazine (2.6 g), sodium carbonate (2.3 g) and tetrakistriphenylphosphine palladium (0.05 g) were added thereto. The temperature was slowly raised to reflux for 15 h, and the temperature was lowered to room temperature. Water and toluene were added for separation. The organic layer was washed with water, dried with magnesium sulfate, and after removing the desiccant, it was concentrated to dryness and crystallized from toluene twice to obtain 2.7 g of compound 1.

[0052] The mass spectrometry detection of compound P1 was performed: the mass-to-charge ratio (m / z) was measured to be 731.30.

[0053] Synthesis Examples 2 to 10:

[0054] Synthesis Examples 2 to 10 respectively provide a bisindole compound and a synthesis method thereof. The synthesis method refers to the synthesis method provided in Synthesis Example 1, with the only difference being that 2-chloro-4,6-diphenyl-1,3,5-triazine is replaced by an equal amount of a triazine compound (see Table 2 for details), and the bisindole compounds are subjected to mass spectrometry detection, and the mass-to-charge ratios (m / z) measured are shown in Table 1 for details.

[0055] Table 1: Mass-to-charge ratio values ​​of synthetic examples 2 to 10

[0056]

[0057]

[0058]

[0059] The synthesis methods of the compounds not listed can refer to the above embodiments and the common methods in the art.

[0060] The specific structures of several materials used in the embodiments of the organic electroluminescent device of the present invention are as follows:

[0061]

[0062] Application Example 1:

[0063] This application example provides a red organic electroluminescent device, the structure of which is:

[0064] ITO / HT-1:PD-1[3%](20nm) / HT-1(40nm) / EB-1(20nm) / host material:RD-1[8%](35nm) / ETL-1:ET-2[50%](300nm) / LiF(0.5nm) / Al(150nm).

[0065] The preparation method of the red organic electroluminescent device is as follows:

[0066] The materials are placed in a vacuum chamber, evacuated to 1×10-5~1×10-6Pa, and vacuum-deposited onto a cleaned ITO substrate in sequence to prepare an OLED device.

[0067] Among them, RD-1[8%] refers to the doping ratio of the dye, that is, the volume ratio of the main material to the dye RD-1 is 92:8; HT-1:PD-1[3%] refers to the ratio of the P-type dopant, that is, the volume ratio of the hole material HT-1 and the P-type dopant PD-1 is 97:3. HT-1 is a hole transport material; HT-1:PD-1[3%] is used as a hole injection layer. The main material of the light-emitting layer in this application example is the bisindole compound P1.

[0068] Application Example 2-4:

[0069] Application Examples 2-4 respectively provide a red organic electroluminescent device, which differs from Application Example 1 only in that the main material of the light-emitting layer, the bisindole compound P1, is replaced by other bisindole compounds (see Table 1 for details), and the other preparation steps and conditions are the same as those of Application Example 1.

[0070] Comparative application example 1:

[0071] Comparative Application Example 1 provides an organic electroluminescent device, which differs from Application Example 1 only in that the main material of the light-emitting layer, the bisindole compound P1, is replaced by other compounds (see Table 2 for details), and the other preparation steps and conditions are the same as those of Application Example 1.

[0072] Performance test comparison:

[0073] The specific test method is as described above, and the test results are shown in Table 2:

[0074] Table 2: Performance test comparison table

[0075] Main material <![CDATA[Luminance / (cd / m 2 )]]> Current efficiency / (cd / A) LT95 / (h) Comparative Application Example 3 H-1 1000 18.0 69 Application Example 1 P1 1000 25.6 121 Application Example 2 P2 1000 24.3 108 Application Example 3 P3 1000 29.5 143 Application Example 4 P4 1000 27.8 137 Application Example 5 P5 1000 24.3 112 Application Example 6 P6 1000 23.9 101 Application Example 7 P7 1000 27.1 123 Application Example 8 P8 1000 26.5 111 Application Example 9 P9 1000 24.4 141 Application Example 10 P10 1000 25.8 89

[0076] It can be seen from the contents of Table 2 that the present invention can improve the current efficiency and service life of the organic electroluminescent device by using the bisindole compound with a specific structure as the main material of the light-emitting layer of the red organic electroluminescent device.

[0077] In summary, the structure of the bisindole compound is designed in the present invention to make it suitable as the main material of the light-emitting layer of the organic electroluminescent device, and the organic electroluminescent device prepared thereby has higher current efficiency and longer service life.

[0078] The above description is only a preferred example of the present invention and is not intended to limit the present invention. Although the present invention is described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A bisindole compound containing a condensed aromatic ring, characterized in that: Its specific structural chemical formula I is: Wherein: Ar1 and Ar2 are each independently selected from any one of C6 to C40 aromatic groups, phenyl, biphenyl, 9,9-dimethylfluorenyl, naphthyl, triphenylene, fluoranthene, phenanthryl, dibenzofuranyl, dibenzothienyl, naphthodibenzofuranyl, and naphthodibenzothienyl; and the hydrogen atom is substituted by at least one of -D, -F, -CN, C6 to C20 aromatic groups, C6 to C20 heteroaryl groups, C1 to C20 alkyl groups, and C1 to C20 alkoxy groups.

2. A bisindole compound containing a fused-ring aromatic group according to claim 1, characterized in that: The C6 to C40 aromatic group is selected from any one of phenyl, biphenyl, terphenyl, naphthyl, anthracenyl, phenanthryl, fluorenyl, benzofluorenyl, dibenzofluorenyl, naphthfluoroenyl, pyrene, perylenyl, spirofluorenyl, triphenylene, fluoranthenyl, hydrogenated benzanthryl, indenofluorenyl, benzoindenofluorenyl, dibenzoindenofluorenyl, naphthfluoroenyl, and benzonaphthofluorenyl.

3. A bisindole compound containing a fused-ring aromatic group according to claim 1, characterized in that: The hydrogen atoms in the bisindole compound containing a condensed ring aromatic group are substituted with at least one of phenyl, naphthyl, biphenyl, fluorenyl, dibenzofuran, dibenzothiophene, methyl, ethyl, propyl, butyl, cyclohexyl, adamantyl, methoxy, ethoxy, propoxy and butoxy groups.

4. A bisindole compound containing a fused-ring aromatic group according to claim 1, characterized in that: The bisindole compound containing a condensed aromatic group is replaced by any one of the following twenty compounds, including:

5. A method for preparing a bisindole compound containing a condensed aromatic ring as claimed in any one of claims 1 to 4, characterized in that: The specific steps include: Step a: First synthesize the intermediate M1. The specific synthesis process is as follows: Step b: Further synthesizing the intermediate M1 obtained in step a to obtain a bisindole compound containing a condensed aromatic ring. The specific synthesis process is as follows:

6. The method for preparing a bisindole compound containing a fused-ring aromatic group according to claim 5, wherein the preparation step of the intermediate M1 in step a comprises: Step a1: under nitrogen protection, add dry toluene, 2-chloro-10,10-methyl-9,11-diphenyl-10,11-dihydro-9H-benzo[6,7]cycloheptane[2,1-b:4,5-b']diindole, bipyraclostrobin, PdCl2(PPh3), and KOAc into a three-necked flask, heat to reflux, cool to room temperature after reaction, and then add water to dilute; Step a2: Then, the organic layer was washed with water until neutral, dried with magnesium sulfate, filtered to remove the magnesium sulfate, concentrated to dryness, separated by silica gel column chromatography, and eluted with a solvent of petroleum ether: ethyl acetate = 50:1 by volume to obtain intermediate M1; Step a3: Finally, the intermediate M1 is subjected to mass spectrometry to measure the mass-to-charge ratio.

7. The method for preparing a bisindole compound containing a fused-ring aromatic group according to claim 5, wherein the further synthesis operation in step b comprises: Step b1: under nitrogen protection, add dioxane and water in a three-necked flask in sequence, and then add intermediate M1, 2-chloro-4,6-diphenyl-1,3,5-triazine, sodium carbonate and tetrakistriphenylphosphine palladium; slowly heat up to reflux reaction, cool to room temperature, add water and toluene for separation, wash the organic layer with water, and dry it with magnesium sulfate; Step b2: After removing the desiccant, the mixture is concentrated to dryness and crystallized from toluene to obtain a bisindole compound containing a condensed ring aromatic group; Step b3: Finally, the bisindole compounds containing condensed ring aromatic groups are subjected to mass spectrometry detection to measure the mass-to-charge ratio.

8. The method for preparing a bisindole compound containing a fused ring aromatic group according to claim 7, wherein the 2-chloro-4,6-diphenyl-1,3,5-triazine is replaced by a triazine compound.

9. An application of a bisindole compound containing a condensed ring aromatic group as claimed in any one of claims 1 to 4, characterized in that: The bisindole compound containing a condensed aromatic ring is applied to an organic electroluminescent device, which comprises an anode, a cathode and an organic thin film layer arranged between the anode and the cathode, wherein the organic thin film layer comprises a light-emitting layer, and the components of the light-emitting layer include the bisindole compound containing a condensed aromatic ring.

10. The use of a bisindole compound containing a condensed ring aromatic group according to claim 9, characterized in that: The organic electroluminescent device is a phosphorescent organic electroluminescent device.

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