A compound and its application

Abstract

The present invention provides a compound and application thereof. The compound has a structure of formula I and is used as a material for an electron transport layer in an organic electroluminescent device. The organic electroluminescent device comprises a first electrode, a second electrode and an organic layer between the first electrode and the second electrode, and the organic layer contains any one or a combination of at least two of the compounds. The compound has high electron injection and migration performance. When the compound is used as an electron transport layer material in an organic electroluminescent device, the luminous efficiency of the device can be improved and the starting voltage of the device can be reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of organic electroluminescence, in particular to a compound and its application, and especially to a compound and its application, and an organic electroluminescent device containing the compound. Background Art

[0002] Organic electroluminescent (OLED: Organic Light Emission Diodes) devices are a type of device with a sandwich-like structure, including positive and negative electrode film layers and organic functional material layers sandwiched between the electrode film layers. When voltage is applied to the electrodes of the OLED device, positive charges are injected from the positive electrode and negative charges are injected from the negative electrode. Under the action of the electric field, the positive and negative charges migrate in the organic layer and meet to combine and emit light. Due to the advantages of high brightness, fast response, wide viewing angle, simple process, and flexibility, OLED devices have attracted much attention in the fields of new display technology and new lighting technology. At present, this technology has been widely used in display panels of new lighting fixtures, smart phones, tablet computers and other products, and will further expand to the application fields of large-size display products such as televisions. It is a new display technology with fast development and high technical requirements.

[0003] As OLED continues to advance in the two major fields of lighting and display, people are paying more attention to the research on its core materials. This is because an OLED device with good efficiency and long life is usually the result of an optimized combination of device structure and various organic materials, which provides great opportunities and challenges for chemists to design and develop functional materials of various structures. Common functional organic materials include: hole injection materials, hole transport materials, hole blocking materials, electron injection materials, electron transport materials, electron blocking materials, luminescent host materials and luminescent guests (dyes), etc.

[0004] To prepare OLED light-emitting devices with lower driving voltage, better luminous efficiency and longer device life, and to continuously improve the performance of OLED devices, it is necessary not only to innovate the structure and manufacturing process of OLED devices, but also to continuously study and innovate the optoelectronic functional materials in OLED devices to prepare functional materials with higher performance. Based on this, the OLED material industry has been committed to developing new organic electroluminescent materials to achieve low device starting voltage, high luminous efficiency and better device life.

[0005] In order to further meet the ever-increasing demand for the optoelectronic performance of OLED devices and the energy-saving needs of mobile electronic devices, it is necessary to continuously develop new and efficient OLED materials, among which the development of new electron transport materials with high electron injection ability and high mobility is of great significance. Summary of the invention

[0006] In view of the deficiencies of the prior art, one of the objects of the present invention is to provide a compound having a structure of formula (I):

[0007]

[0008] In formula (I), R a are independently selected from any one of deuterium, halogen, cyano, nitro, hydroxyl, C1-C12 chain alkyl, C1-C12 alkoxy, C3-C12 cycloalkyl, substituted or unsubstituted C6-C60 aryl, substituted or unsubstituted C3-C60 heteroaryl, and R a It is connected to the parent ring by a single bond, and the parent ring is pyridotriazole. If the parent ring appears in the following text, the meaning is the same as here, and no further details will be given in the following text;

[0009] In formula (I), b is an integer of 0-4 (e.g., 0, 1, 2, 3 or 4), wherein if the value of b is greater than 1, the parent ring is substituted with at least two R a , at least two R a It can be selected from the same group or different groups, and those skilled in the art can select and adjust according to actual needs; the meanings referred to in the following text are the same as here and will not be repeated;

[0010] In formula (I), b is an integer of 2-4 (e.g., 2, 3 or 4), R a They are not connected to each other to form a ring;

[0011] In formula (I), L is selected from any one of a single bond, a C1-C12 chain alkylene group, a C3-C12 cycloalkylene group, a substituted or unsubstituted C6-C30 arylene group, and a substituted or unsubstituted C3-C30 heteroarylene group;

[0012] In formula (I), Ar is selected from any one of cyano, substituted or unsubstituted C6-C60 aryl, and substituted or unsubstituted C3-C60 heteroaryl;

[0013] R aIn , L and Ar, the substituted groups are each independently selected from one of halogen, cyano, nitro, hydroxyl, C1-C12 chain alkyl, C3-C10 cycloalkyl, C1-C10 alkoxy, C1-C10 thioalkoxy, C6-C30 arylamino, C3-C30 heteroarylamino, C6-C30 monocyclic aryl, C10-C30 condensed ring aryl, C3-C30 monocyclic heteroaryl, C6-C30 condensed ring heteroaryl, or at least one of A combination of two, wherein the halogen includes fluorine, chlorine, bromine and iodine; a monocyclic aromatic group refers to a molecule containing one or at least two phenyl groups. When the molecule contains at least two phenyl groups, the phenyl groups are independent of each other and connected by a single bond, such as phenyl, biphenyl and terphenyl; a fused aromatic group refers to a molecule containing at least two benzene rings, but the benzene rings are not independent of each other, but are fused to each other by sharing the ring edge, such as naphthyl, anthracenyl, pyrenyl, peryl, alkyl, etc.; a monocyclic heteroaryl group refers to a molecule containing at least one heteroaryl group. When the molecule contains one heteroaryl group and other groups (such as aryl, heteroaryl, alkyl, etc.), the heteroaryl group and the other groups are independent of each other and connected by a single bond, such as pyridine, furan, thiophene, etc.; a fused-ring heteroaryl group refers to a condensation of at least one phenyl group and at least one heteroaryl group, or a condensation of at least two heteroaryl rings, such as quinoline, isoquinoline, o-phenanthroline, benzofuran, dibenzofuran, benzothiophene, dibenzothiophene, etc.

[0014] In the present invention, Ca-Cb means that the number of carbon atoms of the group is ab, such as C1-C10 means that the number of carbon atoms of the group is 1-10. It should be noted that the number of carbon atoms does not include the number of carbon atoms of the substituent.

[0015] The C1-C12 can be C2, C3, C4, C5, C6, C7, C8, C9, C10, or C11.

[0016] The C3-C12 can be C4, C5, C6, C7, C8, C9, C10, or C11.

[0017] The C6-C60 can be C12, C14, C16, C18, C20, C26, C28, C30, C32, C34, C36, C38, C40, C42, C44, C46, ​​C48, C50, C52, C54, C56, C58, etc.

[0018] The C3-C60 can be C4, C6, C8, C10, C12, C14, C16, C18, C20, C26, C28, C30, C32, C34, C36, C38, C40, C42, C44, C46, ​​C48, C50, C52, C54, C56, C58, etc.

[0019] The C3-C30 can be C4, C6, C8, C10, C12, C14, C16, C18, C20, C26, C28, C30, etc.

[0020] The C6-C30 can be C8, C10, C12, C14, C16, C18, C20, C26, C28, C30, etc.

[0021] The C6-C40 can be C8, C10, C12, C14, C16, C18, C20, C22, C24, C26, C28, C30, C32, C34, C36, C38, etc.

[0022] The C1-C10 can be C2, C3, C4, C5, C6, C7, C8, C9, etc.

[0023] The C1-C6 can be C2, C3, C4, C5, etc.

[0024] In the present invention, the heteroatom in the "heteroaryl" involved is usually selected from any one of N, O or S or a combination of at least two of them; if the "heteroaryl" is involved in the following text, the selection of the heteroatom therein is the same as here, and no specific details are given in the following text.

[0025] The compound provided by the present invention uses pyridotriazole as the parent ring, and forms a new electron transport material by introducing a cyano group, a substituted or unsubstituted C6-C60 aryl group, or a substituted or unsubstituted C3-C60 heteroaryl group. The formed new material has good molecular dipole moment and vapor deposition film-forming property, so that the compound has higher electron injection and migration performance.

[0026] The compound provided by the invention is used in an organic electroluminescent device to improve the electron injection and migration efficiency of the device, thereby improving the luminous efficiency of the device and reducing the starting voltage of the device.

[0027] Preferably, the R a Independently selected from any one of a substituted or unsubstituted C6-C60 aryl group, and a substituted or unsubstituted C3-C60 heteroaryl group;

[0028] Preferably, the R a Independently selected from any one of substituted or unsubstituted C6-C40 aryl groups.

[0029] Preferably, the R a Independently selected from any one of the following substituted or unsubstituted groups:

[0030]

[0031] Wherein, * indicates the connection site.

[0032] In the present invention, * represents the connection site with the parent ring. If * appears in the following text, the meaning is the same as here and will not be repeated in the following text.

[0033] Preferably, the R a Independently selected from any one of the following substituted or unsubstituted groups:

[0034]

[0035] Preferably, b is 0 or 1.

[0036] Preferably, L is selected from any one of a substituted or unsubstituted C6-C30 arylene group and a substituted or unsubstituted C3-C30 heteroarylene group;

[0037] Preferably, L is selected from substituted or unsubstituted C6-C30 arylene groups.

[0038] Preferably, L is selected from substituted or unsubstituted C6-C18 arylene groups.

[0039] Preferably, L is selected from any one of the following substituted or unsubstituted groups:

[0040]

[0041] Wherein, * indicates the connection site.

[0042] Preferably, L is selected from any one of the following substituted or unsubstituted groups:

[0043]

[0044] Wherein, * indicates the connection site.

[0045] Preferably, Ar is selected from any one of a substituted or unsubstituted C6-C30 aryl group and a substituted or unsubstituted C3-C30 heteroaryl group.

[0046] Preferably, Ar is selected from any one of substituted or unsubstituted C3-C30 heteroaryl groups.

[0047] Preferably, Ar is selected from any one of substituted or unsubstituted C3-C30 electron-deficient heteroaryl groups.

[0048] In the present invention, "electron-deficient heteroaryl" is an "electron-deficient group", wherein "electron-deficient group" refers to a group with a Hammett value greater than 0.6, and the larger the Hammett value, the stronger the electronegativity. The Hammett value refers to the characterization of the charge affinity of a specific group, which is a measure of an electron-withdrawing group (positive Hammett value) or an electron-donating group (negative Hammett value). The Hammett equation is described in more detail in Thomas H. Lowry and Katheleen Schueller Richardson, "Mechanism and Theory In Organic Chemistry', New York, 1987, pp. 143-151, which is cited herein as a reference.

[0049] Preferably, Ar is selected from any one of the groups (Hy-1) to (Hy-4):

[0050]

[0051] (Hy-1), Y1, Y2, Y3, Y4, Y5 and Y6 are each independently selected from CR or N atom, and at least one of Y1, Y2, Y3, Y4, Y5 and Y6 is N atom;

[0052] (Hy-2), wherein Z1, Z2, Z3, Z4 and Z5 are each independently selected from CR or N atom, and at least one of Z1, Z2, Z3, Z4 and Z5 is N atom;

[0053] (Hy-3), Z6, Z7, Z8, Z9, Z 10 , Z 11 , Z 12 and Z 13 are each independently selected from CR or N atoms, and Z6, Z7, Z8, Z9, Z 10 , Z 11 , Z 12 and Z 13 At least one of them is a N atom;

[0054] In (Hy-4), Y7, Y8, Y9, Y 10 , Y 11 , Y 12 and Y 13 are each independently selected from CR or N atoms, and Y7, Y8, Y9, Y 10 , Y 11 , Y 12 and Y 13 At least one of them is a N atom;

[0055] R is independently selected from any one of hydrogen, deuterium, halogen, cyano, nitro, hydroxyl, C1-C12 chain alkyl, C1-C12 alkoxy, C3-C12 cycloalkyl, substituted or unsubstituted C6-C60 aryl, substituted or unsubstituted C3-C60 heteroaryl, and the substituted group is selected from any one of halogen, C1-C10 chain alkyl, C3-C10 cycloalkyl, C2-C10 alkenyl, C1-C6 alkoxy, C1-C6 thioalkoxy, C6-C30 monocyclic aromatic group, C10-C30 condensed aromatic group, C3-C30 monocyclic heteroaryl, C6-C30 condensed heteroaryl;

[0056] Among them, * indicates the connection site;

[0057] Preferably, in (Hy-1), 2-4 (eg, 2, 3 or 4) of Y1, Y2, Y3, Y4, Y5 and Y6 are N atoms.

[0058] Preferably, in (Hy-2), 2-4 (eg, 2, 3 or 4) of Z1, Z2, Z3, Z4 and Z5 are N atoms.

[0059] Preferably, in (Hy-3), Z6, Z7, Z8, Z9, Z 10 , Z 11 , Z 12 and Z 13 2-4 (eg 2, 3 or 4) of the atoms are N atoms.

[0060] Preferably, in (Hy-4), Y7, Y8, Y9, Y 10 , Y 11 , Y 12 and Y 13 There are 2-4 N atoms in it.

[0061] Preferably, Ar is selected from any one of the following substituted or unsubstituted groups:

[0062]

[0063] Preferably, Ar is selected from any one of the following groups:

[0064]

[0065] Among them, * indicates the connection site;

[0066] Preferably, Ar is selected from

[0067] As a preferred technical solution of the present invention, the compound has a structure shown by C1-C270 (see Table 1 above), and the compound has high electron injection and migration performance, and can be used as an electron transport layer material in an organic electroluminescent device; wherein, in order to clearly indicate the specific structure of the compound, the general formula of the compound is annotated as in the above formula (I-1), and in the annotation of formula (I-1), 1, 2, 3 and 4 have no specific meaning, but simply represent R a The group is substituted at the specific position of the parent ring. When R a When all groups are selected from hydrogen, the default value of b is 0. a When the group is not selected from hydrogen, the default value of b is the same as R a The groups are not selected from the group having the same number of hydrogen atoms.

[0068] A second object of the present invention is to provide an application as described in the first object, wherein the application is a material used as an electron transport layer in an organic electroluminescent device.

[0069] The third object of the present invention is to provide an organic electroluminescent device, which comprises a first electrode, a second electrode and an organic layer between the first electrode and the second electrode, wherein the organic layer contains the compound described in one of the objects.

[0070] More specifically, an organic electroluminescent device is described in detail.

[0071] An OLED (organic electroluminescent device) includes a first electrode, a second electrode, and an organic material layer between the electrodes. The organic material can be divided into multiple regions. For example, the organic material layer can include a hole transport region, a light emitting layer, and an electron transport region.

[0072] In a specific embodiment, a substrate may be used below the first electrode or above the second electrode. The substrate is a glass or polymer material with excellent mechanical strength, thermal stability, water resistance, and transparency. In addition, a thin film transistor (TFT) may also be provided on the substrate used as a display.

[0073] The first electrode can be formed by sputtering or depositing the material used as the first electrode on the substrate. When the first electrode is used as an anode, an oxide transparent conductive material such as indium tin oxide (ITO), indium zinc oxide (IZO), tin dioxide (SnO2), zinc oxide (ZnO) and any combination thereof can be used. When the first electrode is used as a cathode, a metal or alloy such as magnesium (Mg), silver (Ag), aluminum (Al), aluminum-lithium (Al-Li), calcium (Ca), magnesium-indium (Mg-In), magnesium-silver (Mg-Ag) and any combination thereof can be used.

[0074] The organic material layer can be formed on the electrode by vacuum thermal evaporation, spin coating, printing, etc. The compound used as the organic material layer can be organic small molecules, organic macromolecules and polymers, and combinations thereof.

[0075] The hole transport region is located between the anode and the light-emitting layer. The hole transport region can be a hole transport layer (HTL) of a single-layer structure, including a single-layer hole transport layer containing only one compound and a single-layer hole transport layer containing multiple compounds. The hole transport region can also be a multi-layer structure including at least one layer of a hole injection layer (HIL), a hole transport layer (HTL), and an electron blocking layer (EBL).

[0076] The material of the hole transport region can be selected from, but not limited to, phthalocyanine derivatives such as CuPc, conductive polymers or polymers containing conductive dopants such as polyphenylene ethylene, polyaniline / dodecylbenzenesulfonic acid (Pani / DBSA), poly(3,4-ethylenedioxythiophene) / poly(4-styrenesulfonate) (PEDOT / PSS), polyaniline / camphorsulfonic acid (Pani / CSA), polyaniline / poly(4-styrenesulfonate) (Pani / PSS), aromatic amine derivatives such as the compounds shown in HT-1 to HT-34 below; or any combination thereof.

[0077]

[0078]

[0079]

[0080] The hole injection layer is located between the anode and the hole transport layer. The hole injection layer can be a single compound material or a combination of multiple compounds. For example, the hole injection layer can use one or more compounds of HT-1 to HT-34 mentioned above, or one or more compounds of HI-1 to HI-3 below; or one or more compounds of HT-1 to HT-34 can be doped with one or more compounds of HI-1 to HI-3 below.

[0081]

[0082] The light-emitting layer includes a light-emitting dye (i.e., dopant) that can emit different wavelength spectra, and may also include a host material (Host). The light-emitting layer can be a monochrome light-emitting layer that emits a single color such as red, green, and blue. A plurality of monochrome light-emitting layers of different colors can be arranged in a plane according to a pixel pattern, or they can be stacked together to form a color light-emitting layer. When light-emitting layers of different colors are stacked together, they can be separated from each other or connected to each other. The light-emitting layer can also be a single color light-emitting layer that can simultaneously emit different colors such as red, green, and blue.

[0083] According to different technologies, the light-emitting layer material can be made of different materials such as fluorescent electroluminescent materials, phosphorescent electroluminescent materials, and thermally activated delayed fluorescent materials. In an OLED device, a single light-emitting technology can be used, or a combination of multiple different light-emitting technologies can be used. These different light-emitting materials classified by technology can emit light of the same color or different colors.

[0084] In one aspect of the present invention, the light-emitting layer adopts fluorescent electroluminescence technology. The fluorescent host material of the light-emitting layer can be selected from, but not limited to, one or more combinations of BFH-1 to BFH-17 listed below.

[0085]

[0086]

[0087] In one aspect of the present invention, the light-emitting layer adopts fluorescent electroluminescence technology. The fluorescent dopant of the light-emitting layer can be selected from, but not limited to, one or more combinations of BFD-1 to BFD-12 listed below.

[0088]

[0089] In one aspect of the present invention, the light-emitting layer adopts phosphorescent electroluminescence technology, and the main material of the light-emitting layer is selected from, but not limited to, one or more combinations of GPH-1 to GPH-80.

[0090]

[0091]

[0092]

[0093]

[0094] In one aspect of the present invention, the light-emitting layer adopts phosphorescent electroluminescence technology. The phosphorescent dopant of the light-emitting layer can be selected from, but not limited to, one or more combinations of GPD-1 to GPD-47 listed below.

[0095]

[0096]

[0097]

[0098] Where D is deuterium.

[0099] In one aspect of the present invention, the light-emitting layer adopts phosphorescent electroluminescence technology. The phosphorescent dopant of the light-emitting layer can be selected from, but not limited to, one or more combinations of RPD-1 to RPD-28 listed below.

[0100]

[0101]

[0102] In one aspect of the present invention, the light-emitting layer adopts phosphorescent electroluminescence technology. The phosphorescent dopant of the light-emitting layer can be selected from, but not limited to, one or more combinations of YPD-1 to YPD-11 listed below.

[0103]

[0104] The organic electroluminescent device of the present invention comprises an electron transport region between a light-emitting layer and a cathode. The electron transport region may be a single-layer electron transport layer (ETL), including a single-layer electron transport layer containing only one compound and a single-layer electron transport layer containing multiple compounds. The electron transport region may also be a multilayer structure including at least one layer of an electron injection layer (EIL), an electron transport layer (ETL), and a hole blocking layer (HBL).

[0105] The electron transport region can also be formed by using the compound of the present invention for a multilayer structure including at least one layer of an electron injection layer (EIL), an electron transport layer (ETL), and a hole blocking layer (HBL). Of course, the material of the electron transport region can also be a combination of one or more of ET-1 to ET-57 listed below.

[0106]

[0107]

[0108]

[0109]

[0110] The device may also include an electron injection layer located between the electron transport layer and the cathode. The electron injection layer material includes, but is not limited to, one or more combinations of the following:

[0111] Liq, LiF, NaCl, CsF, Li2O, Cs2CO3, BaO, Na, Li, Ca.

[0112] Compared with the prior art, the present invention has the following beneficial effects:

[0113] The compound provided by the invention has high electron injection and migration performance; using the compound in an organic electroluminescent device can improve the electron injection and migration efficiency of the device, thereby improving the luminous efficiency of the device and reducing the starting voltage of the device. DETAILED DESCRIPTION

[0114] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0115] The compounds of the synthesis methods not mentioned in the present invention are all raw materials obtained through commercial channels. The solvents and reagents used in the present invention, such as ethyl acetate, sodium sulfate, toluene, tetrahydrofuran, dichloromethane, potassium carbonate and other chemical reagents, can be purchased from the domestic chemical product market, such as Shanghai Titan Technology Co., Ltd., Xilong Chemical Co., Ltd., etc.

[0116] The present invention will be described in detail below with reference to a number of specific embodiments. The compounds of the present invention can be prepared by referring to the following general synthetic formula.

[0117] Synthetic formula 1:

[0118]

[0119] The first step: 2-halogenated bromopyridine and hydrazine hydrate undergo substitution reaction to generate intermediate M1-1; the second step: intermediate M1-1 undergoes condensation reaction with chloroaldehyde substances (e.g., chlorobenzaldehyde) to generate intermediate M1-2; the third step: intermediate M1-2 undergoes oxidation ring closure under the action of iodobenzene acetate to generate intermediate M1-3; the fourth step: intermediate M1-3 undergoes Suzuki coupling reaction to generate intermediate M1-4; the fifth step: intermediate M1-4 undergoes Suzuki coupling reaction to generate target product Cx;

[0120] Wherein, Ra, b, L and Ar have the same defined ranges as in claim 1, and X is selected from halogen.

[0121] If Ar is a cyano group, the compound can also be prepared by referring to the following general synthesis formula 2:

[0122] Synthetic formula 2:

[0123]

[0124] The difference between the synthetic formula 2 and the synthetic formula 1 is that the chloroaldehyde substance in the second step is replaced by a cyano-substituted aldehyde substance, and the rest of the synthetic methods are basically the same.

[0125] The analysis and detection of the intermediates and compounds in the present invention were performed using a ZAB-HS mass spectrometer (Micromass, UK).

[0126] Synthesis example 1

[0127] Synthesis of compound C11

[0128]

[0129] (1) Preparation of Compound 1-1

[0130] At room temperature, 2-iodo-5-bromopyridine (283 g, 1 mol) and hydrazine hydrate (313 g, 5 mol, 80%) were added to a flask containing 1.5 L of pyridine, and the mixture was heated to reflux for about 12 hours under stirring. The reaction was completed by TLC detection. The mixture was cooled to room temperature and the solvent was removed by vacuum rotary evaporation to obtain an off-white solid 1-1, which was washed with petroleum ether and filtered, and then directly used for the next step after drying.

[0131] (2) Preparation of Compound 1-2

[0132] The crude compound 1-1,4-chlorobenzaldehyde (210 g, 1.5 mol) obtained in the previous step was added to a flask containing ethanol (3 L), and after replacing nitrogen, the mixture was stirred and refluxed for about 15 hours, and the reaction end point was monitored by TLC. The mixture was cooled to room temperature, and the solid was filtered, washed with ethanol and petroleum ether respectively, and dried to obtain compound 1-2 (250 g, yield 81%).

[0133] (3) Preparation of Compound 1-3

[0134] Compound 1-2 (247.2 g, 0.8 mol) was added to a flask containing ethanol (3 L), and after replacing nitrogen, an ethanol solution containing iodobenzene acetate (322 g, 1 mol) was slowly added dropwise at room temperature. After the addition was completed, the reaction was continued to stir at room temperature for about 6 hours, and the end point of the reaction was monitored by TLC. The mixture was cooled to room temperature, and the solvent was removed by rotary evaporation under reduced pressure. The crude compound was dissolved in DCM and purified by column chromatography and dried to obtain compound 1-3 (128 g, yield 52%).

[0135] (4) Preparation of Compound 1-4

[0136] Compound 1-3 (30.7 g, 100 mmol), 9-phenanthrene boronic acid (24.4 g, 110 mmol), potassium carbonate (41.4 g, 300 mmol) were added to a flask containing toluene / ethanol / water (300 / 100 / 100 mL), and after replacing the nitrogen, Pd(PPh3)4 (1.2 g, 1 mmol) was added. After the addition, the mixture was stirred under nitrogen atmosphere and refluxed for about 4 hours, and the end point of the reaction was monitored by TLC. The mixture was cooled to room temperature, separated, and the aqueous phase was extracted with ethyl acetate. The organic phases were combined, dried over anhydrous sodium sulfate, filtered, and the solvent was removed by vacuum rotary evaporation. The crude product was purified by column chromatography to obtain compound 1-4 (36 g, yield 89%).

[0137] (5) Preparation of Compound 1-5

[0138] Compound 1-4 (20.2 g, 50 mmol), bipyraclostrobin (19 g, 75 mmol) and potassium acetate (14.7 g, 150 mmol) were added to a flask containing 1,4-dioxane (300 mL), and palladium acetate (224 mg, 1 mmol) and SPhos (820 mg, 2 mmol) were added after nitrogen was replaced under stirring at room temperature. After the addition was completed, the reaction was stirred and refluxed for 10 hours, and the reaction endpoint was monitored by TLC. 1,4-dioxane was removed by rotary evaporation, and water and dichloromethane were added for separation. The organic phase was washed with saturated brine, dried over anhydrous sodium sulfate, and purified by column chromatography to obtain compound 1-5 (21 g, yield 83%).

[0139] (6) Preparation of Compound C11

[0140] Compound 1-5 (10 g, 20 mmol), 2-chloro-4,6-diphenyl-1,3,5-triazine (5.4 g, 20 mmol), potassium carbonate (8.3 g, 60 mmol), pd(dppf)Cl2 (146 mg, 0.2 mmol) were added to a flask containing 150 mL tetrahydrofuran and 30 mL water, and the nitrogen was replaced and heated under reflux in a nitrogen atmosphere for about 8 hours. TLC showed that the reaction was complete. The precipitated solid was filtered, washed with water and ethanol respectively, dried, separated and purified by column chromatography to obtain compound C11 (8.9 g, yield 74%). Molecular weight calculated value: 602.22, measured value m / z: 602.2.

[0141] Synthesis example 2

[0142] Synthesis of compound C47

[0143]

[0144] The only difference from the preparation method of Synthesis Example 1 is that 4-chlorobenzaldehyde is replaced by 3-chlorobenzaldehyde, and 9-phenanthreneboric acid is replaced by 2-boric acid-9,9-dimethylfluorene. The calculated molecular weight of the obtained compound C47 is 618.25, and the measured value m / z is 618.3.

[0145] Synthesis example 3

[0146] Synthesis of compound C69

[0147]

[0148] (1) Preparation of Compound 3-4

[0149] Compound 3-4 was prepared by a synthetic method similar to that of compound 1-4, except that the raw material 2-iodo-5-bromopyridine was replaced by 2,6-dibromopyridine, and 9-phenanthreneboric acid was replaced by 3-phenylphenylboric acid.

[0150] (2) Preparation of compound C69

[0151] Compound 3-4 (7.6 g, 20 mmol), 2,4-diphenyl-6 (4-boronic acid ester phenyl) -1,3,5-triazine (8.7 g, 20 mmol), potassium carbonate (8.3 g, 60 mmol), PD2 (DBA) 3 (184 mg, 0.2 mmol), Sphos (164 mg, 0.4 mmol), were added to a flask containing 150 mL 1,4-dioxane and 15 mL water, and the nitrogen was replaced and heated under reflux in a nitrogen atmosphere for about 10 hours. TLC showed that the reaction was complete. The precipitated solid was filtered, washed with water and ethanol respectively, and then dried and separated and purified by column chromatography to obtain compound C69 (9.1 g, yield 70%). The calculated molecular weight value is 654.25, and the measured value m / z is 654.2.

[0152] Synthesis example 4

[0153] Synthesis of compound C93:

[0154]

[0155] The preparation method differs from that of Synthesis Example 1 only in that 4-chlorobenzaldehyde is replaced by 4-cyanobenzaldehyde, and 9-phenanthreneboric acid is replaced by 2-boric acid-9,9-spirobifluorene. The calculated molecular weight of the obtained compound C93 is 534.18, and the measured value m / z is 534.2.

[0156] Synthesis example 5

[0157] Synthesis of compound C158

[0158]

[0159] The preparation method differs from that of Synthesis Example 3 only in that 3-phenylboronic acid is replaced by 2-boronic acid-9,9-spirobifluorene, and 2,4-diphenyl-6 (4-boronate phenyl) -1,3,5-triazine is replaced by 4-cyanophenylboronic acid. The molecular weight of the obtained compound C158 is calculated to be 610.22, and the measured value m / z is 610.2.

[0160] Synthesis example 6

[0161] Synthesis of compound C245

[0162]

[0163] The preparation method differs from Synthesis Example 4 only in that 2-chloro-4,6-diphenyl-1,3,5-triazine is replaced by 9-bromo-10(2-naphthyl)anthracene. The calculated molecular weight of the obtained compound C245 is 522.18, and the measured value m / z is 522.2.

[0164] Example 1

[0165] This embodiment provides an organic electroluminescent device, and the preparation process thereof is as follows:

[0166] The glass plate coated with the ITO transparent conductive layer was ultrasonically treated in a commercial cleaning agent, rinsed in deionized water, ultrasonically degreased in a mixed solvent of acetone:ethanol, baked in a clean environment until the water was completely removed, cleaned with ultraviolet light and ozone, and bombarded with a low-energy cation beam;

[0167] Place the glass substrate with the anode in a vacuum chamber and evacuate the chamber to a vacuum of less than 1×10 -5 Pa, vacuum evaporating the hole injection material HI-3 on the above anode layer as a hole injection layer, the evaporation rate is 0.1nm / s, and the evaporation film thickness is 10nm;

[0168] HT-4 was vacuum-deposited on the hole injection layer as the first hole transport layer of the device, with a deposition rate of 0.1 nm / s and a total deposition thickness of 40 nm;

[0169] Vacuum evaporate HT-14 on the first hole transport layer as the second hole transport layer of the device, the evaporation rate is 0.1nm / s, and the total evaporation film thickness is 10nm;

[0170] The light-emitting layer of the device is vacuum-evaporated on the second hole transport layer. The light-emitting layer includes a main material and a dye material. The evaporation rate of the main material BFH-4 is adjusted to 0.1nm / s by a multi-source co-evaporation method. The evaporation rate of the dye BFD-4 is set at 5%, and the total evaporation film thickness is 20nm.

[0171] ET-17 was vacuum-deposited on the light-emitting layer as the hole blocking layer of the device, with a deposition rate of 0.1 nm / s and a total deposition film thickness of 5 nm;

[0172] Compound C11 and ET-57 were evaporated on the hole blocking layer by a multi-source co-evaporation method as an electron transport layer, the evaporation rate of compound C11 was adjusted to 0.1 nm / s, and the ratio of the evaporation rate of compound C11 to ET-57 was set to 100% (the evaporation rate of compound C11 and ET-57 was 1:1), and the total evaporation film thickness was 23 nm;

[0173] LiF with a thickness of 1 nm was vacuum evaporated on the electron transport layer (ETL) as the electron injection layer, and an Al layer with a thickness of 80 nm was used as the cathode of the device.

[0174] Embodiment 2-6

[0175] The only difference from Example 1 is that C11 is replaced by the compounds synthesized in Synthesis Examples 2-6 in sequence.

[0176] Comparative Example 1

[0177] The only difference from Example 1 is that C11 is replaced by D-1.

[0178] Comparative Example 2

[0179] The only difference from Example 1 is that C11 is replaced by D-2.

[0180]

[0181] Performance Test:

[0182] At the same brightness, the driving voltage and current efficiency of the organic electroluminescent devices prepared in Examples 1-6 and Comparative Examples 1-2 were measured using a PR 750 photoradiometer from Photo Research, a ST-86LA luminance meter (from Beijing Normal University Photoelectric Instrument Factory), and a Keithley 4200 test system. Specifically, the voltage was increased at a rate of 0.1 V per second, and the driving voltage and current efficiency of the organic electroluminescent devices were measured when the brightness reached 1000 cd / m 2 The voltage at this time is the driving voltage, and the current density at this time is measured at the same time; the ratio of brightness to current density is the current efficiency;

[0183] The performance test results are shown in Table 2.

[0184] Table 2

[0185] Electron transport materials <![CDATA[Required brightness (cd / m 2 )]]> Voltage (V) Current efficiency (cd / A) Example 1 Compound C11 1000.00 3.97 9.01 Example 2 Compound C47 1000.00 3.81 9.17 Example 3 Compound C69 1000.00 3.92 9.13 Example 4 Compound C93 1000.00 3.78 9.32 Example 5 Compound C158 1000.00 3.73 9.36 Example 6 Compound C245 1000.00 3.88 9.21 Comparative Example 1 Compound D-1 1000.00 4.56 7.78 Comparative Example 2 Compound D-2 1000.00 4.73 8.04

[0186] It can be seen from Table 1 that, when other materials in the structure of the organic electroluminescent device are the same, the organic electroluminescent devices provided by Examples 1 to 6 of the present invention have higher current efficiency and lower driving voltage.

[0187] The driving voltage of the device using the compound of comparative example 1 and comparative example 2 as the electron transport material is 4.56V and 4.73V respectively, and the current efficiency is 7.78cd / A and 8.04cd / A respectively, which is more different in performance than the device of embodiment. It is speculated that the reason may be that the compound of the present invention adopts pyridotriazole to form a new electron transport material by bridging with triazine, pyrimidine, quinazoline, cyano and other electron-deficient groups, and the molecules formed by azaphenanthroline triazole or isoquinoline triazole bridged triazine are compared with the molecules of the comparative example molecules. In the present invention, the molecule has a more suitable molecular dipole moment, which causes its electron injection ability to be stronger. In addition, the molecule of the present invention has good evaporation film-forming property, and can have close contact with adjacent organic layers when forming a device, so as to be more conducive to the improvement of electron mobility.

[0188] This proves that the new electron transport material composed of the electron-deficient group of the pyridotriazole compound of the present invention bridged with electron-deficient groups such as triazine, pyrimidine, quinazoline, cyano, etc. has higher electron injection and migration performance, thereby making the device have higher current efficiency and lower driving voltage.

[0189] The above experimental data show that the novel organic material of the present invention is an organic light-emitting functional material with good performance as an electron transport material for an organic electroluminescent device and has broad application prospects.

[0190] The applicant declares that the above is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention shall fall within the protection scope and disclosure scope of the present invention.

Claims

1. A compound, characterized in that The compound has the structure of formula (I): In formula (I), R a is selected from any one of substituted or unsubstituted C6-C30 aryl groups, and R a It is connected to the parent ring by a single bond, and the parent ring is pyridotriazole; In formula (I), b is 1; In formula (I), L is selected from any one of substituted or unsubstituted C6-C20 arylene groups; In formula (I), Ar is selected from cyano, substituted or unsubstituted Any of the following: Among them, * indicates the connection site; R a , L and Ar, the substituted groups are each independently selected from one or a combination of at least two of halogen, cyano, C1-C12 chain alkyl, C3-C10 cycloalkyl, C1-C10 alkoxy, C1-C10 thioalkoxy, C6-C30 monocyclic aromatic group, C10-C30 condensed ring aromatic group.

2. The compound according to claim 1, characterized in that The R a Independently selected from any one of the following substituted or unsubstituted groups: Wherein, * indicates the connection site.

3. The compound according to claim 1, characterized in that The R a Independently selected from any one of the following groups:

4. The compound according to claim 1, characterized in that The L is selected from any one of the following substituted or unsubstituted groups: Wherein, * indicates the connection site.

5. The compound according to claim 1, characterized in that The L is selected from any one of the following substituted or unsubstituted groups:

6. The compound according to claim 1, characterized in that The Ar is 7. The compound according to claim 1, characterized in that The Ar is selected from cyano or 8. A compound, characterized in that The compound has the structure of formula (I-1): In the compound C1-C270 of the formula (I-1), R a , L and Ar are selected from the groups shown in Table 1: Table 1 Among them, the 1st bit R a Refers to R a Substituted at position 1 of the parent ring is selected from the group, R at position 2 a Refers to R a Substituted at the 2-position of the parent ring is selected from the group, and R at the 3-position a Refers to R a Substituted at the 3-position of the parent ring is selected from the group, and R at the 4-position a Refers to R a Substituted at the 4-position of the parent ring is a group selected from; * indicates the attachment site to the parent ring.

9. Use of a compound according to any one of claims 1 to 8, characterized in that: The application is as a material for an electron transport layer in an organic electroluminescent device.

10. An organic electroluminescent device, characterized in that: The organic electroluminescent device comprises a first electrode, a second electrode and an organic layer between the first electrode and the second electrode, wherein the organic layer is an electron transport layer and contains the compound according to any one of claims 1 to 8.

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