Red light and infrared light-emitting compounds based on boron-nitrogen fused ring and application of red light and infrared light-emitting compounds

Abstract

The invention provides a red light and infrared light-emitting compound based on a boron-nitrogen fused ring and application thereof. The invention provides a boron-nitrogen polycyclic aromatic hydrocarbon material of a fused naphthalene ring, and a specific strong electron withdrawing group is introduced to a boron atom para-position. Compared with a compound disclosed in the prior art, the compound provided by the invention introduces a strong electron withdrawing group to a boron atom para-position of boron-nitrogen polycyclic aromatic hydrocarbon of a fused naphthalene ring, so that the emission spectrum of the material can be subjected to significant red shift (red shift from a yellow light band to a red light band and even an infrared band), and red light and even infrared light emission with high luminous efficiency and a narrow band can be realized. An electroluminescent device prepared from the compound provided by the invention shows relatively high luminescent color purity and relatively excellent luminous efficiency, and can meet the requirements of current enterprise production on high-performance luminescent materials.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of organic light-emitting materials, and particularly relates to a kind of red and infrared light-emitting compounds based on boron-nitrogen fused ring and application thereof. BACKGROUND

[0002] Due to the limitation of the band gap law, narrow band gap light-emitting materials such as red and infrared light-emitting materials usually have strong non-radiative transition, resulting in low light-emitting efficiency; at the same time, their strong molecular excited state vibration transition often leads to wide reflection arc spectrum and low color purity. Low light-emitting efficiency, wide spectrum and low color purity of red and infrared light emission are very unfavorable for their application in optoelectronic devices, biological imaging and diagnosis and treatment, etc.

[0003] Takuji Hatakeyama et al. of Kansai Gakuin University in Japan proposed a new frontier orbital separation strategy, designed and synthesized a kind of multi-resonance thermally activated delayed fluorescence (MR-TADF) material based on boron-nitrogen fused ring arene. Due to the fused ring structure, the molecular plane of this kind of molecule is rigid, and it usually has high emission efficiency and narrow emission half-width (<30 nm), so it has attracted widespread attention from researchers. However, most of this kind of material emits blue and green light, and it is quite challenging to develop MR-TADF for red and even infrared emission in molecular design, and there are few related reports. SUMMARY

[0004] The present application provides a kind of red and infrared light-emitting compounds based on boron-nitrogen fused ring, which is a compound as shown in the following formula (I):

[0005]

[0006] Wherein, R1, R2, R3 are the same or different, and are independently selected from H, C 1-12 alkyl, C 1-12 alkoxy;

[0007] A1, A2 are electron acceptor units, which are the same or different, and are independently selected from electron-withdrawing groups, such as strong electron-withdrawing groups.

[0008] According to an embodiment of the present application, A1, A2 are electron acceptor units, which are the same or different, and are independently selected from halogen, cyano, nitro, aldehyde group, phosphine oxide (P=O), halogenated C 1-12 alkyl, C 6-20 aryl, -CO-5-25 membered heteroaryl, C 6-20 aryl, 5-25 membered heteroaryl, C 1-12 alkylsulfonyl, C 6-20 arylsulfonyl, C 2-12alkyl, haloC 1-12 alkyl, haloC 6-20 alkyl, haloC 1-12 alkyl, haloC 6-20 alkyl, haloC 1-12 alkyl, haloC 1-12 alkyl, haloC 2-12 alkyl, haloC 1-12 alkyl, haloC 6-20 alkyl, haloC

[0009] Ra is selected from =0, cyano, C 1-12 alkyl, haloC 1-12 alkyl, haloC 2-12 alkyl, haloC 1-12 alkyl, haloC 1-6 alkyl, haloC 1-6 alkyl, haloC

[0010] Rb is selected from =0, cyano, C 1-6 alkyl, haloC 1-6 alkyl, haloC 6-14 alkyl, haloC 2-6 alkyl, haloC 1-6 alkyl, haloC 6-14 alkyl, haloC 1-6 alkyl, haloC 6-14 alkyl, haloC

[0011] According to an embodiment of the present application, R1, R2, R3 are identical or different, independently from each other, selected from H, C 1-6 alkyl, haloC 1-6 alkyl, haloC

[0012] According to an embodiment of the present application, A1, A2 are electron acceptor units, identical or different, independently from each other, selected from halogen, cyano, nitro, aldehyde, phosphine oxide (P=0), haloC 1-6 alkyl, haloC 1-6 alkyl, haloC 6-14 alkyl, haloC 2-6 alkyl, haloC 1-6 alkyl, haloC 6-14 alkyl, haloC 1-6 alkyl, haloC 6-14 alkyl, haloC

[0013] Ra is selected from halogen, =0, cyano, C 1-6 alkyl, haloC 1-6 alkyl, haloC 2-6 alkyl, haloC 1-6 alkyl, haloC

[0014] Rb is selected from halogen, =0, cyano, C 1-6 alkyl, haloC 1-6 alkyl, oxoC 2-6 alkyl, C 1-6 alkoxy.

[0015] According to an embodiment of the present application, R1, R2, R3 are identical and selected from H, C 1-6 alkyl, C 1-6 alkoxy, for example H, C 1-3 alkyl, C 1-3 alkoxy.

[0016] According to an embodiment of the present application, A1, A2 are identical and selected from Cl, Br or a group as shown below:

[0017]

[0018] wherein Rc is C 1-6 alkyl or 5-14 membered aryl;

[0019] Rd, Rf are identical or different and independently from each other selected from halogen, cyano, nitro, aldehyde, phosphine oxide (P=0) or haloC 1-6 alkyl;

[0020] Rg is C 1-6 alkyl;

[0021] denotes the presence or absence of this substituent.

[0022] According to an embodiment of the present application, wherein Rc is C 1-4 alkyl or phenyl;

[0023] Rd, Rf are identical or different and independently from each other selected from halogen, cyano, nitro, aldehyde, phosphine oxide (P=0) or haloC 1-3 alkyl;

[0024] Rg is C 1-4 alkyl;

[0025] denotes the presence or absence of this substituent.

[0026] According to an embodiment of the present application, Rc is methyl, ethyl, n-propyl, i-propyl, t-butyl or phenyl;

[0027] Rd, Rf are identical or different and independently from each other selected from Cl, Br, cyano, nitro, aldehyde, phosphine oxide (P=0), trifluoromethyl or trichloromethyl;

[0028] Rg is methyl, ethyl, n-propyl, i-propyl, t-butyl;

[0029] - indicates the presence or absence of this substituent.

[0030] According to an embodiment of the present application, R1, R2, R3 are identical and selected from H, methyl, ethyl, methoxy, ethoxy.

[0031] According to an embodiment of the present application, A1, A2 are identical and selected from Cl, Br or a group as shown below:

[0032]

[0033]

[0034] According to an embodiment of the present application, the compound of formula (I) is selected from the group consisting of compounds having the following structures:

[0035]

[0036] The present application also provides a method for preparing the compound of formula (I) as described above, comprising the following steps: when A1 and A2 are selected from halogen, the method comprises:

[0037] S1) ring-closing reaction of the compound of formula I-1 with BBr3 to obtain the compound of formula I, wherein A1 and A2 are selected from halogen;

[0038]

[0039] When A1 and A2 are selected from groups other than halogen, the method comprises:

[0040]

[0041] S2) reaction of the compound of formula I’ with A-L to obtain the compound of formula I, wherein A1 and A2 are selected from groups other than halogen;

[0042] wherein A is A1 and A2, and L is X is halogen;

[0043] or, L is A1 and A2, A is halogen, and X is

[0044] wherein R1, R2, R3 have the definitions as described above

[0045] A1, A2 are selected from groups other than halogen as defined above.

[0046] wherein the method for preparing the compound of formula I’ can refer to step S1).

[0047] The application also provides a use of the compound shown in the above formula (I) as a light-emitting material in the preparation of an organic electronic device, preferably, in the preparation of an organic electroluminescent device.

[0048] According to an embodiment of the application, the compound shown in formula (I) has photoluminescence or electroluminescence properties and can emit red light or infrared light.

[0049] The application also provides an organic electroluminescent device comprising two electrodes and an organic layer between the electrodes, wherein the organic layer comprises the compound shown in the above formula (I).

[0050] Preferably, the organic layer comprises one, two or more of an injection layer, a transport layer, a light-emitting layer, and a blocking layer.

[0051] Preferably, the compound shown in formula (I) is located in the light-emitting layer as a light-emitting material.

[0052] The application also provides a preparation method of the organic electroluminescent device, comprising the following steps: arranging an organic layer between two electrodes, wherein the organic layer comprises the compound shown in formula (I).

[0053] According to an embodiment of the application, the organic electroluminescent device is prepared by sequentially arranging an anode, a hole injection layer, a hole transport layer, an electron blocking layer, a light-emitting layer, a hole blocking layer, an electron transport layer, an electron injection layer, and a cathode on a substrate.

[0054] Preferably, the arrangement of the anode, the hole injection layer, the hole transport layer, the electron blocking layer, the light-emitting layer, the hole blocking layer, the electron transport layer, the electron injection layer, and the cathode is performed by evaporation, spin coating or inkjet, for example, by evaporation.

[0055] More preferably, the evaporation is performed under vacuum, for example, the evaporation of organic materials is performed under a vacuum degree of less than 1x10 -5 Pa, and further preferably, the evaporation rate and thickness of each functional layer are precisely controlled by using a quartz crystal film thickness detector.

[0056] Advantages:

[0057] The application provides a kind of red light and infrared light-emitting compound based on boron-nitrogen fused ring and its application.Compared with known light-emitting materials, the compound has the following advantages:

[0058] 1. The application designs a kind of boron-nitrogen fused ring arene compound of fused naphthalene ring, and innovatively introduces electron-withdrawing group in para position of boron atom, which can obtain high luminescent efficiency and narrow spectral band of red light and infrared light emission. At the same time, the molecular structure is strong in expandability, and the light color is easy to control.

[0059] 2. Compared with MR-TADF materials of most boron-nitrogen fused ring aromatic hydrocarbons, the synthetic preparation process using the MR-TADF compound of the present application is simple, high in yield, and the raw materials used in the synthesis are easily available and inexpensive.

[0060] 3. The electroluminescent device prepared by using a kind of red and infrared light-emitting compound based on boron-nitrogen fused ring has excellent performance (high color purity and high luminous efficiency).

[0061] In summary, the present application provides a kind of fused naphthalene ring boron-nitrogen fused ring aromatic hydrocarbon material, and specific strong electron-withdrawing group is introduced at boron atom para position of fused naphthalene ring boron-nitrogen fused ring aromatic hydrocarbon.Compared with the compound disclosed in the prior art, the compound of the present application introduces strong electron-withdrawing group at boron atom para position of fused naphthalene ring boron-nitrogen fused ring aromatic hydrocarbon, which can significantly red shift the emission spectrum of the material (red shift from yellow light band to red light or even infrared band), realize high luminous efficiency and narrow band red light or even infrared light emission.The electroluminescent device prepared using the compound provided by the present application exhibits high luminous color purity and excellent luminous efficiency, which can meet the requirements of current enterprise production for high-performance light-emitting materials.

[0062] Definitions and explanations of terms

[0063] Unless otherwise specified, the definitions of groups and terms in the specification and claims of the present application, including the definitions of examples, exemplary definitions, preferred definitions, definitions in tables, definitions of specific compounds in examples, etc., can be combined and combined with each other. The group definition and compound structure after such combination shall belong to the scope of protection of the present application.

[0064] The numerical range recorded in the specification and claims of the present application shall be understood as recording the two endpoints of the range and each integer in the range when the numerical range can only be "integer". For example, the number of carbon atoms "1-5" shall be understood as recording each integer of 1, 2, 3, 4, 5.

[0065] "More" means three or more.

[0066] The "halogen" used in the present application refers to fluorine, chlorine, bromine and iodine.

[0067] The term "C 1-12 "Alkyl" is understood to mean a straight-chain or branched saturated monovalent hydrocarbon group having 1 to 12 carbon atoms, preferably C 1-6 "Alkyl". "C 1-6 "Alkyl" is understood to mean a straight-chain or branched saturated monovalent hydrocarbon group having 1, 2, 3, 4, 5 or 6 carbon atoms. The alkyl group is, for example, methyl, ethyl, propyl, butyl, isopropyl, isobutyl, sec-butyl, tert-butyl, in particular the group has 1, 2 or 3 carbon atoms ("C 1-3"alkyl" is understood as meaning a straight-chain or branched saturated monovalent hydrocarbon group having from 1 to 12 carbon atoms, in which case at least one hydrogen atom, for example 1, 2, 3, 4, 5 or 6 hydrogen atoms, is replaced by halogen, preferably by halogeno-Ci-4-alkyl, more preferably by trifluoromethyl.

[0068] The term "halo-Ci-4-alkyl" is understood as meaning a straight-chain or branched saturated monovalent hydrocarbon group having 1, 2, 3 or 4 carbon atoms, in which at least one hydrogen atom, for example 1, 2, 3 or 4 hydrogen atoms, is replaced by halogen, preferably by fluorine. 1-12 "alkyl" is understood as meaning a straight-chain or branched saturated monovalent hydrocarbon group having from 1 to 12 carbon atoms, in which case at least one hydrogen atom, for example 1, 2, 3, 4, 5 or 6 hydrogen atoms, is replaced by halogen, preferably by halogeno-Ci-4-alkyl, more preferably by trifluoromethyl. 1-6 "alkyl" is understood as meaning a straight-chain or branched saturated monovalent hydrocarbon group having from 1 to 12 carbon atoms, in which case at least one hydrogen atom, for example 1, 2, 3, 4, 5 or 6 hydrogen atoms, is replaced by halogen, preferably by halogeno-Ci-4-alkyl, more preferably by trifluoromethyl.

[0069] The term "5- to 25-membered heteroaryl" is understood as meaning a monovalent, monocyclic, bicyclic or tricyclic aromatic ring system or more than three aromatic ring systems having from 5 to 25 ring atoms and comprising from 1 to 5 heteroatoms independently selected from N, O and S, for example "5- to 14-membered heteroaryl". The term "5- to 14-membered heteroaryl" is understood as meaning a monovalent, monocyclic, bicyclic or tricyclic aromatic ring system having from 5, 6, 7, 8, 9, 10, 1 1, 12, 13 or 14 ring atoms, in particular 5 or 6 or 9 or 10 carbon atoms, and comprising from 1 to 5, preferably from 1 to 3, heteroatoms each independently selected from N, O and S and, in each case additionally, can be benzo-fused. In particular, the heteroaryl is selected from the group consisting of thienyl, furanyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyrazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, thiadiazolyl, thia-4H-pyrazolyl and the like and their benzo derivatives, for example benzo furanyl, benzo thienyl, benzo oxazolyl, benzo isoxazolyl, benzo imidazolyl, benzo triazolyl, indazolyl, indolyl, isoindolyl and the like; or pyridyl, pyridazinyl, pyrimidinyl, pyrazinyl, triazinyl and the like and their benzo derivatives, for example quinolinyl, quinazolinyl, isoquinolinyl and the like; or azocinyl, indolizinyl, purinyl and the like and their benzo derivatives; or cinnolinyl, phthalazinyl, quinazolinyl, quinoxalinyl, naphthyridinyl, pteridinyl, carbazolyl, acridinyl, phenoxazinyl, phenothiazinyl, phenoxazinyl and the like. The "more than three aromatic ring systems" are, for example, 15- to 25-membered ring hydrocarbon ring aromatic ring systems comprising from 1 to 5 heteroatoms independently selected from N, O and S.

[0070] The term "C 6-20 "aryl" is understood as meaning a monovalent aromatic or partially aromatic, monocyclic, bicyclic or tricyclic hydrocarbon ring having from 6 to 20 carbon atoms, preferably "C6-14-aryl". The term "C 6-14 "aryl" is understood as meaning a monovalent aromatic or partially aromatic, monocyclic, bicyclic or tricyclic hydrocarbon ring having from 6 to 20 carbon atoms, preferably "C6-14-aryl". The term "C 6-14 "aryl" is understood as meaning a monovalent aromatic or partially aromatic, monocyclic, bicyclic or tricyclic hydrocarbon ring having from 6 to 20 carbon atoms, preferably "C6-14-aryl". The term "C10 aryl") having 13 carbon atoms, for example tetrahydronaphthyl, dihydronaphthyl or naphthyl, or a ring ("C 13 aryl") having 13 carbon atoms, for example tetrahydronaphthyl, dihydronaphthyl or naphthyl, or a ring ("C 14 aryl") having 13 carbon atoms, for example tetrahydronaphthyl, dihydronaphthyl or naphthyl, or a ring ("C 6-20 When the C

[0071] The term "C 1-12 alkyl" is to be understood as meaning "C 1-12 alkyl", wherein "C 1-12 alkyl" has the meaning given above.

[0072] The term "oxa-C 2-12 alkyl" is to be understood as meaning a straight-chain or branched saturated, monovalent hydrocarbon group having 2 to 12 carbon atoms, it being possible for 1, 2, 3, 4 carbon atoms to be replaced by O, with the O replacement being in any position except alpha, preferably oxa-C 2-8 alkyl.

[0073] Unless stated otherwise, heterocyclyl, heteroaryl or heteroarylenyl include all possible isomeric forms thereof, for example positional isomers. Thus, for some illustrative, non-limiting examples, pyridyl or pyridinylene includes pyridin-2-yl, pyridin-2- ylene, pyridin-3-yl, pyridin-3-ylene, pyridin-4-yl and pyridin-4-ylene; thienyl or thienylene includes thien-2-yl, thien-2-ylene, thien-3-yl and thien-3-ylene. BRIEF DESCRIPTION OF DRAWINGS

[0074] Figure 1 is the emission spectrum of compound C-4 and compound C-5. DETAILED DESCRIPTION

[0075] The general compounds of the present application, their preparation and use will be further described in conjunction with specific examples below. It should be understood that the following examples are illustrative and are not meant as limitations on the scope of the application. Any technical implementation based on the above description of the present application is encompassed within the scope intended to be protected.

[0076] The starting materials and reagents used in the following examples are either commercially available or can be prepared by known methods, unless otherwise stated.

[0077] Example 1

[0078] The synthesis route of compound C-1 is shown below:

[0079] The synthesis route of compound C-1 is shown below:

[0080] [Synthesis of intermediate compound C-1-3]

[0081] In a dry Schlenk flask was added C-1-1 (5.72 g, 20 mmol), C-1-2 (2.70 g, 20 mmol), NaOtBu (556 mg, 60 mmol), Pd2(dba)3(183 mg, 1%), [(t-Bu)3PH]BF4(332 mg, 4%) and 30 ml of dry toluene, the reaction was refluxed under nitrogen protection for 1 h. The crude product was purified by column chromatography to obtain the product as a white solid (6.40 g). MS: m / z 394.2409 [M + ] ; Elemental analysis: C 28 H 30 N2, calculated (%) : C, 85.24; H, 7.66; N, 7.10; found: C, 85.09; H, 7.49; N, 7.21.

[0082] [Synthesis of intermediate compound C-1-5]

[0083] In a dry Schlenk flask was added C-1-4 (5.34 g, 20 mmol), diphenylamine (3.38 g, 20 mmol), NaOtBu (278 mg, 30 mmol), Pd2(dba)3(183 mg, 1%), DPEphos (430 mg, 4%) and 60 ml of dry toluene, the reaction was heated to 80°C under nitrogen protection for 12 h, the crude product was purified by column chromatography to obtain the product (4.30 g). MS: m / z 356.9920 [M + ] ; Elemental analysis: C 18 H 13 BrClN, calculated (%) : C, 60.28; H, 3.65; N, 3.91; found: C, 60.55; H, 3.64; N, 3.93.

[0084] [Synthesis of intermediate compound C-1-6]

[0085] In a dry Schlenk flask was added C-1-3 (1.96 g, 5 mmol), C-1-5 (3.60 g, 10 mmol), NaOtBu (278 mg, 15 mmol), Pd2(dba)3(230 mg, 2.5%), RuPhos (234 mg, 5%) and 20 ml of dry toluene, the reaction was refluxed under nitrogen protection for 1 h, the product was purified by column chromatography (7.30 g). MS: m / z 933.3491 [M + ] ; Elemental analysis: C63 H 51 Cl2N4, Calc. (%): C, 80.93; H, 5.50; N, 5.99; Found: C, 81.04; H, 5.43; N, 6.07.

[0086] [Synthesis of target product C1]

[0087] C-1-6 (3.74 g, 4 mmol) was added into a high pressure reaction tube, o-dichlorobenzene 40 ml was added under nitrogen protection, BBr3(3.8 ml, 40 mmol), and reacted at 200 °C for 48 hours. After the reaction was completed, dichloromethane was added for extraction, and the organic layer was spin-dried. The crude product was purified by column chromatography to obtain the product as a bright red solid (1.62 g). MS: m / z 964.3442 [M + ] ; Elemental analysis: C 64 H 48 B2Cl2N4, Calc. (%): C, 79.61; H, 5.01; N, 5.80; Found: C, 79.25; H, 4.96; N, 5.75.

[0088] Example 2

[0089] The synthesis route of compound C-4 is shown below:

[0090]

[0091] [Synthesis of intermediate compound C-4-1]

[0092] Pd2(dba)3 (92 mg, 5%) and Xphos (95 mg, 10%) were added to a suspension of C-1 (1.93 g, 2 mmol), bis(pinacolato)diboron (1.03 g, 4 mmol), potassium acetate (0.8 g, 8 mmol) in dioxane (50 ml) at room temperature. After stirring at room temperature for 20 minutes, it was heated to 110 °C and stirred for 12 hours. The reaction mixture was extracted with dichloromethane and further purified by column chromatography to obtain the product as a solid (1.22 g). MS: m / z 1148.5926 [M + ] ; Elemental analysis: C 76 H 72 B4N4O4, Calc. (%): C, 79.47; H, 6.32; N, 4.88; Found: C, 79.49; H, 6.35; N, 4.78.

[0093] [Synthesis of target product C4]

[0094] C-4-1 (1.15 g, 1 mmol), C-4-2 (456 mg, 2 mmol), Pd(PPh3)4 (58 mg, 0.05 mmol), potassium carbonate (0.58 g, 4 mmol), and a mixture of 25 mL ethanol, deionized water, and toluene (ethanol / deionized water / toluene = 1:1:2) were added to a 20 mL Schlenk tube. The mixture was stirred at 100 °C for 12 h under nitrogen protection. The reaction mixture was extracted and purified by column chromatography to give the product (0.30 g). MS: m / z 1278.7067 [M + ]; Elemental analysis: C 86 H 84 B2N 10 Calculated values ​​(%): C, 80.74; H, 6.62; N, 10.95; Measured values: C, 80.55; H, 6.67; N, 10.82.

[0095] Example 3

[0096] The synthetic route for compound C-5 is shown below:

[0097]

[0098] [Synthesis of target product C5]

[0099] C-4-1 (1.15 g, 1 mmol), C-5-1 (436 mg, 2 mmol), Pd(PPh3)4 (58 mg, 0.05 mmol), potassium carbonate (0.58 g, 4 mmol), and a mixture of 25 mL ethanol, deionized water, and toluene (ethanol / deionized water / toluene = 1:1:2) were added to a 20 mL Schlenk tube. The mixture was stirred at 100 °C for 12 hours under nitrogen protection. The reaction mixture was purified by column chromatography after extraction to give the product (0.28 g). MS: m / z 1359.5848 [M + ]; Elemental analysis: C 94 H 68 B2N 10 Calculated values ​​(%): C, 83.06; H, 5.04; N, 10.30; Measured values: C, 83.13; H, 4.98; N, 10.45.

[0100] Example 4

[0101] The synthetic route for compound C-7 is shown below:

[0102]

[0103] [Synthesis of intermediate compound C-7-1]

[0104] 5-Bromoacetylnaphthyl-1,2-dione (2.61 g, 10 mmol) and diaminomaleitrile (1.19 g, 11 mmol) were placed in a 250 mL round-bottom flask, and 100 mL of glacial acetic acid was added as a solvent. The reaction was refluxed under nitrogen protection for 8 h at 125 °C. After the reaction was completed, the mixture was poured into 100 mL of ice water, filtered, and the filter cake was obtained. The crude product was washed with water and ethanol, and dried to obtain a yellow powder (2.80 g). MS: m / z 329.9793 [M + ].

[0105] [Synthesis of target product C7]

[0106] C-4-1 (1.15 g, 1 mmol), C-7-1 (436 mg, 2 mmol), Pd(PPh3)4 (58 mg, 0.05 mmol), potassium carbonate (0.58 g, 4 mmol), and a mixture of 25 mL ethanol, deionized water, and toluene (ethanol / deionized water / toluene = 1:1:2) were added to a 20 mL Schlenk tube. The mixture was stirred at 100 °C for 12 hours under nitrogen protection. The reaction mixture was purified by column chromatography after extraction to give the product (0.39 g). MS: m / z 1397.5317 [M + ]; Elemental analysis: C 100 H 62 B2N8, calculated values ​​(%): C, 85.96; H, 4.47; N, 8.02; measured values: C, 85.59; H, 4.52; N, 8.14.

[0107] Example 5

[0108] The synthetic route for compound C-10 is shown below:

[0109]

[0110] [Synthesis of intermediate compound C-10-1]

[0111] To a two-necked flask containing 100 mL of anhydrous toluene, add 4,8-dibromobenzo[1,2-c:4,5-c']bis([1,2,5]thiadiazole) (1.76 mg, 5 mmol), tributyl(3,5-di-tert-butylphenyl)stanane (2.63 mg, 5.5 mmol), and catalyst Pd(PPh3)2Cl2 (351 mg, 0.5 mmol). After deoxygenation, the reaction was heated to 100 °C and stirred for 10 hours. The crude product was purified by silica gel column chromatography to give the product (602 mg). MS: m / z 460.0391 [M + ].

[0112] [Synthesis of target product C10]

[0113] C-4-1 (0.58 g, 0.5 mmol), C-10-1 (571 mg, 1 mmol), Pd(PPh3)4(58 mg, 0.05 mmol), potassium carbonate (0.58 g, 4 mmol) and 25 mL of a mixed solution of ethanol, deionized water and toluene (ethanol / deionized water / toluene = 1:1:2) were added to a 20 mL Schlenk tube. The reaction mixture was stirred at 100 °C for 12 hours under nitrogen protection. After extraction, the reaction mixture was purified by column chromatography to obtain the product (0.15 g). MS: m / z 1657.6514 [M + ] ; Elemental analysis: C 104 H 90 B2N 12 S4, calculated value (%): C, 75.35; H, 5.47; N, 10.14; measured value: C, 74.95; H, 5.40; N, 10.57.

[0114] Example 6

[0115] Preparation of organic electroluminescent device 1 (OLED-1) (in which compound C-4 accounts for 1% of the total mass of itself and the commercial host material mCBP)

[0116] In this example, compound C-4 was used as the light-emitting material, the commercial host material mCBP was used as the host material, indium tin oxide (ITO) was used as the anode, HAT-CN was used as the hole injection material, TAPC was used as the hole transport material, TCTA was used as the electron blocking material, TmPyPB was used as the electron transport material, Liq was used as the electron injection material, and aluminum (Al) was used as the cathode material, and the device structure was constructed into an electroluminescent device with the structure of ITO / HAT-CN / TAPC / TCTA / mCBP:compound C-4 (1 wt%) / TmPyPB / Liq / Al.

[0117] The preparation process of the above-mentioned electroluminescent device is as follows: a glass substrate with a transparent conductive layer of ITO (100 nm) was cleaned with lye and rinsed with deionized water, then ultrasonically cleaned in deionized water, ethanol and acetone for ten minutes each, baked in a clean environment until there was no solvent residue, and then treated with ultraviolet ozone for 15 minutes. The wafer was placed in a vacuum chamber, vacuumed to less than 2 x 10 -5Pa. On the anode, HAT-CN was deposited at a deposition rate of 0.2 nm / s to form a 10 nm film, TAPC was deposited at a deposition rate of 0.2 nm / s to form a layer with a thickness of 50 nm on the hole injection layer, TCTA was deposited at a deposition rate of 0.2 nm / s to form a 10 nm film on the electron transport layer, compound C-4 and mCBP were simultaneously deposited at a deposition rate of 0.2 nm / s and at a ratio (mass ratio) of 1:100 on the electron blocking layer to form a 20 nm doped film, TmPyPB was deposited at a deposition rate of 0.2 nm / s to form a layer with a thickness of 30 nm as an electron transport layer (ETL). Liq was deposited at a deposition rate of 0.02 nm / s to form a layer with a thickness of 1 nm as an electron injection layer (EIL). Finally, Al was deposited at a deposition rate of 0.5 nm / s on the electron injection layer to form a cathode with a thickness of 100 nm. The final structure of the device was: ITO (100 nm) / HAT-CN (10 nm) / TAPC (50 nm) / TCTA (10 nm) / mCBP: compound C-4 (1 wt%) (20 nm) / TmPyPB (30 nm) / Liq (1 nm) / Al (100 nm).

[0118] Examples 7-9

[0119] Preparation of organic electroluminescent devices 2-5 (OLED-2-5)

[0120] OLED-2-4 were prepared under the same production conditions as OLED-1 except that compound C-5, C-7 and C-10 were used as the doped light-emitting material instead of compound C-4.

[0121] The method for forming each structural layer in the organic electroluminescent device of the present application is not limited, and can use, for example, but not limited to, a conventional vacuum deposition method, a spin coating method, and an inkjet printing method.

[0122] The structures of the compounds involved in Examples 6-9 are as follows:

[0123]

[0124] The current-voltage characteristics and light-emitting characteristics of the organic light-emitting diodes prepared in Examples 7-10 were tested using a characterization device, and important parameters such as external quantum efficiency, light-emitting wavelength and light-emitting half-peak width were recorded (see Table 1 for test results).

[0125] As shown in Table 1, the maximum external quantum efficiency of the light-emitting devices OLED-1 to 5 using the compounds C-4, C-5, C-7 and C-10 as the doped light-emitting material ranges from 5.9% to 21.5%, the light-emitting wavelength ranges from red light to infrared light, and the half-peak width is as narrow as 27 nm, which has obvious resonance characteristic emission. The above data show that the compounds of the present application have the potential to prepare high-performance OLEDs.

[0126] Table 1. Performance test of OLED devices of Examples 6 to 9

[0127]

[0128]

[0129] The above describes exemplary embodiments of the present application. However, the protection scope of the present application is not limited to the above-described embodiments. Any modification, equivalent replacement, improvement, etc. made by those skilled in the art within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. The compound represented by formula (I): in, R1, R2, and R3 may be the same or different, and are independently selected from H and C. 1-12 Alkyl, C 1-12 Alkoxy; A1 and A2 are electron acceptor units, which may be the same or different, and are independently selected from electron-withdrawing groups, such as strong electron-withdrawing groups.

2. The compound according to claim 1, wherein, A1 and A2 are electron acceptor units, which may be the same or different, and are independently selected from halogen, cyano, nitro, aldehyde, phosphino (P=O), and halogenated C groups. 1-12 Alkyl groups, unsubstituted or optionally substituted with one, two or more Ra groups, including the following groups: -CO-C 6-20 Aryl, -CO-5-25 heteroaryl, C 6-20 Aryl, 5-25 quinone heteroaryl, C 1-12 alkylsulfonyl, C 6-20 arylsulfonyl, C 2-12 alkenyl, -Si(C) 1-12 Alkyl)3, -Si(C 6-20 aryl)3,-Si(5-25 heteroaryl)3,-B(C 1-12 Alkyl)2, -B(C 6-20 aryl)2, -B(5-25 heteroaryl)2; Ra is selected from =O, cyano, C 1-12 Alkyl, Halogenated C 1-12 Alkyl, oxaC 2-12 Alkyl, C 1-12 Alkoxy groups, unsubstituted or optionally substituted with one, two or more Rb groups, including the following groups: C 6-20 Aryl, 5-25 quinone heteroaryl; Rb is selected from =O, cyano, and C. 1-12 Alkyl, Halogenated C 1-12 Alkyl, oxaC 2-12 Alkyl, C 1-12 Alkyl group.

3. The compound according to claim 1 or 2, wherein, R1, R2, and R3 are the same, and are selected from H and C. 1-6 Alkyl, C 1-6 Alkoxy groups, such as H and C 1-3 Alkyl, C 1-3 Alkoxy; Alternatively, A1 and A2 are the same, selected from Cl, Br, or the following groups: Where Rc is C 1-6 Alkyl or 5-14 aryl groups; Rd and Rf may be the same or different, and are independently selected from halogen, cyano, nitro, aldehyde, phosphoxy (P=O), or halogenated C. 1-6 alkyl; Rg is C 1-6 alkyl; ------ indicates whether the substituent is present or not.

4. The compound according to claim 3, wherein, Rc is C 1-4 Alkyl or phenyl; Rd and Rf may be the same or different, and are independently selected from halogen, cyano, nitro, aldehyde, phosphoxy (P=O), or halogenated C. 1-3 alkyl; Rg is C 1-4 alkyl; ------ indicates whether the substituent is present or not.

5. The compound according to claim 1 or 2, wherein, R1, R2, and R3 are the same and are selected from H, methyl, ethyl, methoxy, and ethoxy. Alternatively, A1 and A2 are the same, selected from Cl, Br, or the following groups:

6. The compound according to claim 1 or 2, wherein, The compound represented by formula (I) is selected from compounds with the following structures:

7. A method for preparing the compound of formula (I) according to any one of claims 1-6, wherein, The method includes the following steps: when A1 and A2 are selected from halogens, the method includes: S1) The compound shown in Formula I-1 is subjected to a cyclization reaction with BBr3 to obtain A1 and A2, which are compounds of Formula I selected from halogens. When A1 and A2 are selected from groups other than halogens, the method includes: S2) React the compound shown in Formula I' with AL to obtain a compound shown in Formula I whose A1 and A2 are selected from groups other than halogens; Where A represents A1 and A2, and L represents... X is a halogen; Alternatively, L can be A1 and A2, A can be a halogen, and X can be... Wherein, R1, R2, and R3 have the definitions described in any one of claims 1-6; A1 and A2 are selected from groups other than halogens as described in any one of claims 1-6.

8. An organic electroluminescent device comprising two electrodes and an organic layer located between the electrodes, said organic layer comprising a compound of formula (I) as described in any one of claims 1-6.

9. The organic electroluminescent device according to claim 8, wherein, The organic layer includes one, two or more of the following: an injection layer, a transport layer, a light-emitting layer, and a blocking layer.

10. The method for preparing the organic electroluminescent device according to claim 8 or 9, wherein, The method includes the following steps: providing an organic layer between two electrodes, the organic layer comprising the compound of formula (I) as described in any one of claims 1-6.

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