CN116693564A

CN116693564A - Boron-nitrogen compound and preparation method and application thereof

Info

Publication number: CN116693564A
Application number: CN202310623064.6A
Authority: CN
Inventors: 王悦; 李成龙; 梁宝炎; 宋小贤; 毕海
Original assignee: Jihua Hengye Foshan Electronic Materials Co ltd
Current assignee: Jihua Hengye Foshan Electronic Materials Co ltd
Priority date: 2023-05-29
Filing date: 2023-05-29
Publication date: 2023-09-05

Abstract

The invention provides a boron nitrogen compound, a preparation method and application thereof, wherein the boron nitrogen compound has a narrow spectrum, is used as a narrow spectrum luminescent material for preparing a luminescent layer of an organic electroluminescent device, and the prepared organic electroluminescent device realizes narrow spectrum TADF emission, and ensures that the electroluminescent external quantum efficiency of the device is up to more than 30 percent.

Description

Boron-nitrogen compound and preparation method and application thereof

Technical Field

The invention belongs to the technical field of organic electroluminescence, and relates to a boron-nitrogen compound and a preparation method and application thereof.

Background

The organic photoelectric material (Organic Optoelectronic Materials) is an organic material having the characteristics of generation, conversion, transmission and the like of photons and electrons. Currently, controllable photoelectric properties of Organic photoelectric materials have been applied to Organic Light-Emitting diodes (OLEDs), organic solar cells (Organic Photovoltage, OPVs), organic field effect transistors (Organic Field Effect Transistor, OFETs), and even Organic lasers. In recent years, OLEDs have become a very popular new flat display product at home and abroad. The OLED display has the characteristics of self-luminescence, wide viewing angle, short reaction time, high luminous efficiency, wide color gamut, low working voltage, thin panel, capability of manufacturing a large-size flexible panel and low cost, and is known as a star flat display product in the 21 st century.

As regards the history of organic electroluminescence, it can be traced back to the report by Bernanose et al in 1953 (Holst G A, kster T, voges E, et al FLOX-an oxygen-flux-measuring system using a phase-modulation method to evaluate the oxygen-dependent fluorescence lifetime, science directors and operators B: chemical,1995,29,213.), about 10 years later, the fluorescent emission of anthracene was observed by applying a voltage to crystals of anthracene by Pope et al, new York university in 1963 (M.Pope, H.Kallmann and P. Magnante, electroluminescence in Organic Crystals, J. Chem. Phys.,1963,38,2042). In 1987, C.W.Tang et al, kodak, U.S. used an ultrathin film technique to prepare a light-emitting device with an aromatic amine having a good hole transport effect as a hole transport layer, an aluminum complex of 8-hydroxyquinoline as a light-emitting layer, and an Indium Tin Oxide (ITO) film and a metal alloy as an anode and a cathode, respectively. The device obtains brightness of up to 1000cd/m under 10V driving voltage ² The efficiency of the device was 1.5lm/W (c.w. tang and s.a. vanslyke, organic electroluminescent diodes, appl. Phys. Lett.,1987, 51, 913), a breakthrough development has led to rapid and intensive development of organic electroluminescent research worldwide. The first polymer (PPV) -based Light emitting diode was proposed by Burroughes et al, university of cambridge, 1990, which demonstrated that PPV was a highly fluorescent emissive material with high luminous efficiency in single layer devices (Burroughes j.h.et al, light-emitting diodes based on conjugated polymers, nature,1990,347,539.). Baldo and Forrest et al, university of Prencton 1998 report An electroluminescent-based phosphorescent device can have an internal quantum yield of 100% in principle (M.A.Baldo, D.F.O' Briiental, highly efficient phosphorescent emission from organic electroluminescent devices, nature,1998, 395, 151), but on the one hand, the phosphorescent material is generally made of noble metals such as iridium platinum and the like, which are expensive, and on the other hand, the phosphorescent material still has chemical instability, and the device has the problem of large efficiency roll-off under high current density and the like, so that it is very important to develop an OLED device which uses cheap and stable small organic molecular materials and can realize high-efficiency luminescence.

In 2012, adachi' S group reports that highly efficient fully fluorescent OLED devices based on the Thermally Activated Delayed Fluorescence (TADF) mechanism (Uoyama H, goushi K, shizu K, et al Highly efficient organic light-emitting diodes from delayed fluorescence, nature,2012,492 (7428):234-238.) can absorb thermal energy when the S1 and T1 energy levels of the molecule are sufficiently small, return to singlet state through RISC process, and thus fluoresce, and their Internal Quantum Efficiency (IQE) can theoretically reach 100%, and External Quantum Efficiency (EQE) even up to 30%, as compared to the level of shoulder phosphorescence devices. As a next-generation light-emitting material, a TADF material is being studied.

The TADF molecules are primarily doped as guest materials in a wide bandgap host material to achieve high efficiency thermally activated delayed fluorescence (Q.Zhang, J.Li, K.Shizu, et al design of Efficient Thermally Activated Delayed Fluorescence Materials for Pure Blue Organic Light Emitting Diodes, J.Am.chem.Soc.2012,134,14706; H.Uoyama, K.Goushi, K.Shizu, H.Nomura, C.Adachi, highly efficient organic light-emitting diodes from delayed fluorescence, nature,2012,492,234;T.Nishimoto,T.Yasuda,et al., asix-carbazole-decorated cyclophosphazene as a host with high triplet energy to realize efficient delayed-fluorescence OLEDs, mater.Horiz.,2014,1,264). Unlike traditional fluorescent molecular Localized (LE) state luminescence, TADF emission is mainly derived from transitions in ICT state, and is therefore susceptible to interdonor-acceptor vibration and rotational movement, resulting in a broader spectrum. The broad spectrum, while advantageous for illumination applications, does not meet the high color purity requirements of the display field. While the most important use of OLEDs is in display, narrow spectral designs (i.e., smaller full width at half maximum, FWHM) of TADF materials are necessary.

Disclosure of Invention

Aiming at the defects of the prior art, the invention aims to provide a boron-nitrogen compound, and a preparation method and application thereof. The compound provided by the invention aims to overcome the defect of TADF luminescent molecules, provides a narrow spectrum luminescent material, and is used for preparing a luminescent layer of an organic electroluminescent device, so that the organic electroluminescent device realizes narrow spectrum TADF emission.

In order to achieve the aim of the invention, the invention adopts the following technical scheme:

in one aspect, the present invention provides a boron nitrogen compound having a structure represented by formula I:

wherein the R is ¹ And R is ² Is H, deuterium, C1-C20 alkyl, C1-C20 alkoxy, C3-C10 cycloalkyl, C6-C14 aryl, substituted by one or more R ^a Substituted C6-C18 aryl, 5-to 18-membered heteroaryl, substituted with one or more R ^a Substituted 5-to 18-membered heteroaryl, diphenylamino, or substituted with one or more R ^a Substituted diphenylamino groups;

R ^a independently at each occurrence deuterium, fluorine, CN, C1-C12 alkyl, C1-C12 alkoxy, C3-C12 cycloalkyl, C6-C14 aryl, substituted with one or more R ^b Substituted C6-C14 aryl, 5-to 18-membered heteroaryl, substituted with one or more R ^b Substituted 5-to 18-membered heteroaryl, diphenylamino, or substituted with one or more R ^b Substituted diphenylamino groups;

R ^b independently at each occurrence deuterium, fluorine, CN, C1-C12 alkyl, C1-C12 alkoxy, C3-C10 cycloalkyl, C6-C14 aryl, substituted with one or more R ^c Substituted C6-C14 aryl, 5-to 18-membered heteroaryl, substituted with one or more R ^c Substituted 5-to 18-membered heteroaryl, diphenylamino, or substituted with one or more R ^c Substituted diphenylamino groups;

R ^c independently at each occurrence deuterium, fluorine, CN, C1-C12 alkyl, C1-C12 alkoxy, C3-C10 cycloalkyl, C6-C14 aryl, substituted with one or more R ^d Substituted C6-C14 aryl, 5-to 18-membered heteroaryl, substituted with one or more R ^d Substituted 5-to 18-membered heteroaryl, diphenylamino, or substituted with one or more R ^d Substituted diphenylamino groups;

R ^d independently at each occurrence deuterium, fluorine, C1-C12 alkyl, C1-C12 alkoxy, C3-C10 cycloalkyl, C6-C14 aryl or by one or more R ^e Substituted C6-C14 aryl;

R ^e independently for each occurrence deuterium, fluorine, C1-C12 alkyl, C1-C12 alkoxy, C3-C10 cycloalkyl, or C6-C14 aryl;

the R is ⁰¹ 、R ⁰² 、R ⁰³ And R is ⁰⁴ Independently selected from H, deuterium, fluorine, C1-C20 alkyl, C1-C20 alkoxy, C3-C12 cycloalkyl, C6-C24 aryl, substituted with one or more R ^g Substituted C6-C18 aryl, 5-to 18-membered heteroaryl, substituted with one or more R ^g Substituted 5-to 18-membered heteroaryl, diphenylamino, or substituted with one or more R ^g Substituted diphenylamino groups;

R ^g each occurrence is independently deuterium, fluorine, C1-C12 alkyl, C1-C12 alkoxy, C3-C12 cycloalkyl, C6-C14 aryl;

the R is ⁰⁵ And R is ⁰⁶ Independently selected from H, deuterium, C1-C20 alkyl, C1-C20 alkoxy, C3-C12 cycloalkyl, C6-C24 aryl;

the alkyl, alkoxy, cycloalkyl, aryl, heteroaryl groups are optionally substituted with one or more substituents selected from the group consisting of: halogen, -CN, C1-C12 alkyl, C1-C12 alkoxy, C1-C12 haloalkyl, C2-C6 alkenyl, C3-C10 cycloalkyl, C6-C14 aryl and 5-to 18-membered heteroaryl.

In one embodiment of the present invention, the boron nitrogen compound wherein R is ¹ And R is ² Independently is H, deuterium, C1-C20 alkyl, C3-C10 cycloalkyl, C6-C18 aryl or 5-to 24-membered heteroaryl.

Preferably, said R ¹ And R is ² Is a C6-C12 aryl or a 5-to 18-membered heteroaryl.

Preferably, R ⁰⁵ And R is ⁰⁶ Independently selected from C6-C12 aryl.

In one embodiment of the present invention, said R ¹ And R is ² Independently is H, deuterium, fluorine, methyl, ethyl, n-propyl, isopropyl, n-butyl, t-butyl, hexyl, octyl, decyl, phenyl, pyridyl, biphenyl, 2-methyl-phenyl, 2, 6-dimethylphenyl, 4-methyl-phenyl, 4-ethyl-phenyl, 4-propyl-phenyl, 4-isopropylphenyl, 4-n-butylphenyl, fluorophenyl, a, Wherein the wavy line represents the attachment site of the group.

In one embodiment of the present invention, the boron nitrogen compound is any one of the following compounds BN-1 to BN-32:

in one embodiment of the present invention, the method for preparing the boron nitrogen compound comprises the steps of:

(1) When m=0 or 1 or 2, the coupling reaction of the first raw material and the second raw material is carried out to obtain a compound BN-n-I, wherein the reaction formula is as follows:

(2) When m=0, the compound BN-n-I can be equivalent to BN-n-II without performing the reaction of this step, in which case the step is skipped directly

(2) Performing step (3);

when m=1, the compound BN-n-I and the raw material III undergo a coupling reaction (1) to obtain a compound BN-n-II;

when m=2, the compound BN-n-I and the raw material III undergo a coupling reaction (2) to obtain a compound pre-BN-n-II, and then the compound pre-BN-n-II and the raw material IV undergo a coupling reaction (3) to obtain a compound BN-n-II, wherein the reaction formula is as follows:

(3) The compound BN-n-II undergoes one-pot lithiation-boronation-cyclization reaction to obtain a boron-nitrogen compound BN-n shown in the formula I, wherein the reaction formula is as follows:

preferably, the reaction of step (1) is carried out in the presence of an alkaline substance;

preferably, the alkaline substance in step (1) is cesium carbonate;

preferably, the molar ratio of the first feedstock to the second feedstock in step (1) is 2 to 6:1, for example 2:1, 2.5:1, 3:1, 3.5:1, 4:1, 4.5:1, 5:1, 5.5:1 or 6:1.

Preferably, the molar ratio of the alkaline substance to the second raw material is 3 to 8:1, for example 3:1, 3.5:1, 4:1, 4.5:1, 5:1, 5.5:1, 6:1, 6.5:1, 7:1, 7.5:1 or 8:1.

Preferably, the solvent for the reaction of step (1) is N, N-dimethylformamide.

Preferably, the temperature of the reaction in step (1) is 120 to 160 ℃ (e.g. 120 ℃, 125 ℃, 130 ℃, 140 ℃, 150 ℃ or 160 ℃) for 8 to 24 hours (e.g. 8 hours, 10 hours, 12 hours, 15 hours, 18 hours, 20 hours, 22 hours or 24 hours).

Preferably, the molar ratio of the compound BN-n-I to the starting material three in the reaction (1) of step (2) is 1:1 to 4, for example 1:1, 1:1.2, 1:1.5, 1:1.8, 1:2, 1:2.2, 1:2.5, 1:2.8, 1:3, 1:3.5, 1:3.8 or 1:4.

Preferably, the molar ratio of compound BN-n-I to starting material three in reaction (2) of step (2) is 1 to 4:1, for example 1:1, 1:1.2, 1:1.5, 1:1.8, 1:2, 1:2.2, 1:2.5, 1:2.8, 1:3, 1:3.5, 1:3.8 or 1:4.

Preferably, the molar ratio of compound pre-BN-n-II to starting material four in reaction (3) of step (2) is 1:1 to 4, e.g. 1:1, 1:1.2, 1:1.5, 1:1.8, 1:2, 1:2.2, 1:2.5, 1:2.8, 1:3, 1:3.5, 1:3.8 or 1:4.

Preferably, the reactions (1), (2) and (3) in step (2) are carried out in the presence of a catalyst.

Preferably, the catalyst in the reactions (1), (2) and (3) in the step (2) is tetrakis (triphenylphosphine) palladium.

Preferably, the catalyst in reaction (1) of step (2) is 0.1% to 10%, for example 0.1%, 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9% or 10% of the molar amount of the compound BN-n-I.

Preferably, the catalyst in reaction (2) in step (2) is 0.1% to 10%, for example 0.1%, 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9% or 10% of the three molar amount of the starting material.

Preferably, the catalyst in reaction (3) of step (2) is 0.1% to 10%, for example 0.1%, 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9% or 10% of the molar amount of the compound pre-BN-n-II.

Preferably, the reactions (1), (2) and (3) in step (2) are carried out in the presence of a weakly basic substance.

Preferably, the weakly basic material in the reactions (1), (2) and (3) in the step (2) is potassium carbonate.

Preferably, the molar ratio of weakly basic material to compound BN-n-I in reaction (1) in step (2) is 2 to 8:1, e.g. 2:1, 2.5:1, 3:1, 3.5:1, 4:1, 4.5:1, 5:1, 5.5:1, 6:1, 6.5:1, 7:1, 7.5:1 or 8:1.

Preferably, the molar ratio of weakly basic material to compound three in reaction (2) in step (2) is from 2 to 8:1, for example 2:1, 2.5:1, 3:1, 3.5:1, 4:1, 4.5:1, 5:1, 5.5:1, 6:1, 6.5:1, 7:1, 7.5:1 or 8:1.

Preferably, the molar ratio of weakly basic material to compound pre-BN-n-II in reaction (3) in step (2) is 2 to 8:1, e.g. 2:1, 2.5:1, 3:1, 3.5:1, 4:1, 4.5:1, 5:1, 5.5:1, 6:1, 6.5:1, 7:1, 7.5:1 or 8:1.

Preferably, the solvent of the reactions (1), (2) and (3) in the step (2) is a mixed solution of tetrahydrofuran and water.

Preferably, the reaction temperature of the reactions (1), (2) and (3) in step (2) is 60 to 100 ℃ (e.g. 60 ℃, 65 ℃, 70 ℃, 80 ℃, 90 ℃ or 100 ℃), and the reaction time is independently 6 to 24 hours (e.g. 6 hours, 8 hours, 10 hours, 12 hours, 15 hours, 18 hours, 20 hours, 22 hours or 24 hours).

Preferably, the lithiation stage in the lithiation-boronation-cyclization reaction of step (3) is performed in the presence of an alkyllithium reagent.

Preferably, the alkyl lithium reagent is t-butyl lithium.

Preferably, the stage of boriding in the lithiation-boriding-cyclisation reaction of step (3) is carried out in the presence of a boron-containing reagent.

Preferably, the boron-containing reagent is boron tribromide.

Preferably, the cyclisation stage in the lithiation-boronation-cyclisation reaction of step (3) is carried out in the presence of an alkaline substance.

Preferably, the basic substance is N, N-diisopropylethylamine.

Preferably, the molar ratio of the compound BN-n-II to the alkyllithium reagent of step (3) is 1:2 to 4, for example 1:2, 1:2.2, 1:2.5, 1:2.8, 1:3, 1:3.5, 1:3.8 or 1:4.

Preferably, the molar ratio of the compound BN-n-II to the boron-containing reagent of step (3) is 1:2 to 6, e.g. 1:2, 1:2.5, 1:2.8, 1:3, 1:3.5, 1:4, 1:4.5, 1:5, 1:5.5 or 1:6.

Preferably, the molar ratio of the compound BN-n-II to the basic substance of step (3) is 1:2 to 8, for example 1:2, 1:2.5, 1:2.8, 1:3, 1:3.5, 1:4, 1:4.5, 1:5, 1:5.5, 1:6, 1:7 or 1:8.

Preferably, the solvent of the reaction of step (3) is tert-butylbenzene.

Preferably, the lithiation stage in the lithiation-boronation-cyclization reaction of step (3) is performed at 0 to 60 ℃ (e.g., 0 ℃, 10 ℃, 20 ℃, 30 ℃, 40 ℃, 50 ℃ or 60 ℃), and the reaction time of the lithiation stage is 2 to 6 hours (e.g., 2 hours, 3 hours, 4 hours, 5 hours or 6 hours).

Preferably, the step (3) is carried out at a temperature of-40 to 25 ℃ (e.g., -40 ℃, -30 ℃, -20 ℃, -10 ℃, 0 ℃, 10 ℃, 20 ℃ or 25 ℃), and the reaction time of the step (3) is 0.5 to 2 hours (e.g., 0.5 hours, 0.8 hours, 1 hour, 1.5 hours, 1.8 hours or 2 hours).

Preferably, the cyclizing stage in the lithiation-boronation-cyclizing reaction of step (3) is carried out at 0 to 140 ℃ (e.g., 0 ℃, 10 ℃, 20 ℃, 30 ℃, 40 ℃, 50 ℃, 60 ℃, 80 ℃, 100 ℃, 120 ℃, or 140 ℃), and the reaction time of the cyclizing stage is 6 to 12 hours (e.g., 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, 11 hours, or 12 hours).

In another aspect, the present invention provides an organic electroluminescent composition comprising the boron nitride compound as described above as a doping material and a host material.

Preferably, the host material is a material having an electron transport ability and/or a hole transport ability and having a triplet excited state energy higher than or equal to that of the dopant material.

In one embodiment of the present invention, the host material in the organic electroluminescent composition is a carbazole derivative and/or carboline derivative having a structure represented by any one of the formulae (H-1) to (H-6):

wherein X is ₁ 、Y ₁ And Z ₁ Is CH or N, and X ₁ 、Y ₁ And Z ₁ At most one of them is N;

wherein R is ^1H And R is ^2H Independently any of the following groups:

wherein R is ^aH And R is ^bH H, C independently ₁ -C ₂₀ Alkyl, C ₁ -C ₂₀ Alkoxy, C ₆ -C ₂₀ Aryl, C ₁ -C ₂₀ Alkyl substituted C ₆ -C ₂₀ Aryl or C ₁ -C ₂₀ Alkoxy substituted C ₆ -C ₂₀ Aryl, number represents the attachment site of the group.

Preferably, the organic electroluminescent composition preferably contains 0.3 to 30.0wt% of the boron-nitrogen compound as described above as a doping material, and the remaining 99.7 to 70.0wt% of the composition is a host material composed of 1 to 2 compounds having structures of formulae (H-1) to (H-6).

Preferably, the host material contains 2 compounds having the structures of formulae (H-1) to (H-6) in a weight ratio of 1:5 to 5:1, for example 1:5, 1:4, 1:3, 1:2, 1:1, 2:1, 3:1, 4:1, 5:1, etc.

Preferably, the host material in the organic electroluminescent composition is one or two of the compounds H1-1 to H1-427.

Preferably, the organic electroluminescent composition contains 0.3-30.0wt% of boron-nitrogen compound with the structure shown in formula I as described above, and the rest 99.7-70.0wt% is 1 or 2 compounds of the compounds H1-1 to H1-427:

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preferably, the organic electroluminescent composition contains 2 compounds from the group of compounds H1-1 to H1-427 as host materials in a weight ratio of 1:5 to 5:1, for example: 1:5, 1:4, 1:3, 1:2, 1:1, 2:1, 3:1, 4:1, 5:1, etc.

Preferably, the doping material in the organic electroluminescent composition is any one of the boron-nitrogen compounds according to any one of claims 1 to 3; the main material is composed of any one of compounds shown as the formulas Trz1-A, trz2-A, trz3-A, trz4-A, trz5-A or Trz6-A and any one of compounds with structures shown as the formulas H-1 to H-6;

wherein R is ^1a 、R ^1b 、R ^2a 、R ^2b 、R ^3a And R is ^3b Wherein 1 or 2 are independently R ^Tz The remainder being the same or different and independently hydrogen, deuterium, C ₁ -C ₈ Alkyl, C ₁ -C ₈ Alkoxy, C ₆ -C ₁₈ Aryl, C ₁ -C ₈ Alkyl substituted C ₆ -C ₁₈ Aryl or C ₁ -C ₈ Alkoxy substituted C ₆ -C ₁₈ Aryl of (a); r is R ^Tz Is any one of substituent groups shown in the following formula:

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wherein asterisks represent the attachment site of the group;

preferably, the weight ratio of Trz1-A, trz2-A, trz3-A, trz4-A, trz5-A or Trz6-A to H-1, H-2, H-3, H-4, H-5 or H-6 is 1:20 to 20:1, for example 1:20, 1:15, 1:10, 1:5, 1:1, 5:1, 10:1, 15:1 or 20:1.

Preferably, the doping material in the organic electroluminescent composition is any one of boron-nitrogen compounds with the structure shown in the formula I; the main material is composed of any one of compounds shown as formulas TRZ-1 to TRZ-80 and any one of carbazole or carboline derivatives shown as formulas H1-1 to H1-427;

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Preferably, the weight ratio between the compound of formulae TRZ-1 to TRZ-80 and the carbazole or carboline derivative in the host material is 1:20 to 20:1, for example 1:20, 1:15, 1:10, 1:5, 1:1, 5:1, 10:1, 15:1 or 20:1.

In another aspect, the present invention provides an organic electroluminescent material comprising a boron nitrogen compound or an organic electroluminescent composition as described above.

In another aspect, the present invention provides an organic electroluminescent device comprising an anode and a cathode and an organic thin film layer interposed between the anode and the cathode, the organic thin film layer comprising the boron nitrogen compound or the organic electroluminescent composition as described above.

Preferably, the organic thin film layer comprises a light emitting layer, an optional hole injection layer, an optional hole transport layer, an optional electron injection layer, wherein at least one of the light emitting layer, the electron injection layer, the electron transport layer, the hole injection layer comprises a boron nitride compound as described above.

In the present invention, the boron nitrogen compound may be used as a functional material in at least one of a light emitting layer, an electron injection layer, an electron transport layer, a hole transport layer, and a hole injection layer of an organic electroluminescent device.

In a certain embodiment of the invention, the material of the light emitting layer in the organic electroluminescent device comprises a boron nitride compound as described above.

In one embodiment of the present invention, the organic electroluminescent composition is a light-emitting layer, and the light-emitting principle of the light-emitting layer is based on energy transfer from a host material to any of the compounds represented by formula I or carrier capture by the light-emitting material itself.

In one embodiment of the invention, the organic electroluminescent composition is a light-emitting layer; the host material in the organic electroluminescent composition may be a carbazole derivative and/or a carboline derivative represented by the formulae (H-1) to (H-6). In a preferred embodiment, the organic electroluminescent composition comprises 0.3-30.0wt% of any one compound represented by formula I, and the remaining 99.7-70.0wt% of the organic electroluminescent composition is a host material composed of 1-2 compounds having structures of formulae (H-1) to (H-6). For example, when the host material contains 2 compounds having the structures of formulae (H-1) to (H-6), the weight ratio of the two compounds is 1:5 to 5:1.

In one embodiment of the invention, the organic electroluminescent composition is a light-emitting layer; the main materials in the composition are 1-2 of the compounds H1-1 to H1-427. In a preferred embodiment, the organic electroluminescent composition comprises 0.3-30.0wt% of any one of the compounds of formula I, and the remaining 99.7-70.0wt% of the composition is 1-2 of the compounds H1-1 to H1-427. For example, when 2 compounds of formulas H1-1 to H1-427 are included in the composition, the weight ratio of the two compounds is 1:5 to 5:1.

In one embodiment of the invention, the organic electroluminescent composition is a light-emitting layer; the doping material in the organic electroluminescent composition is any compound shown in the formula I (the content is 0.3-30.0 wt%); the main body material (content of 99.7wt% -70.0wt%) is composed of any one of the compounds shown as the formula Trz1-A, trz2-A, trz3-A, trz4-A, trz5-A or Trz6-A and any one of the compounds shown as the formulas H-1 to H-6. For example, in the host material, the weight ratio of Trz1-A, trz2-A, trz3-A, trz4-A, trz5-A or Trz6-A compound to the compound indicated as H-1, H-2, H-3, H-4, H-5 or H-6 is 1:20 to 20:1.

In one embodiment of the invention, the organic electroluminescent composition is a light-emitting layer; the doping material in the organic electroluminescent composition is any compound shown in the formula I (the content is 0.3-30.0 wt%); the main material (content of 99.7wt% -70.0wt%) is composed of any one of 1,3, 5-triazine derivatives shown in formulas TRZ-1 to TRZ-81 and any one of carbazole or carboline derivatives shown in formulas H1-1 to H1-427. For example, in the host material, the weight ratio between the 1,3, 5-triazine derivative and the carbazole or carboline derivative is from 1:20 to 20:1.

In one embodiment of the invention, the organic electroluminescent composition is a light-emitting layer; the doping material in the organic electroluminescent composition is any one compound shown in the formulas BN-1 to BN-32 (the content is 0.3wt percent to 30.0wt percent); the main body material (the content is 99.7wt% -70.0wt%) is composed of any one of the compounds shown as the formula Trz1-A, trz2-A, trz3-A, trz4-A, trz5-A and Trz6-A and any one of carbazole or carboline derivatives shown as the formulas H1-1 to H1-427. For example, in the host materials, the weight ratio between the compounds of formulae Trz1-A, trz2-A, trz3-A, trz4-A, trz5-A, and Trz6-A, and carbazole or carboline derivatives of formulae H1-1 to H1-427 is 1:20 to 20:1.

In one embodiment of the present invention, the organic electroluminescent device further comprises a substrate, and an anode layer, an organic light-emitting functional layer and a cathode layer sequentially formed on the substrate; the organic light-emitting functional layer comprises a light-emitting layer containing the organic electroluminescent composition, and can also comprise any one or a combination of at least two of a hole injection layer, a hole transport layer, an electron blocking layer, a hole blocking layer, an electron transport layer and an electron injection layer.

In another aspect, the invention provides an application of the organic electroluminescent device in an organic electroluminescent display or an organic electroluminescent illumination source.

Description of the terms

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

As used herein, the term "comprising" or "including" can be open, semi-closed, and closed. In other words, the term also includes "consisting essentially of …," or "consisting of ….

Definition of groups

In this specification, groups and substituents thereof can be selected by one skilled in the art to provide stable moieties and compounds. When substituents are described by conventional formulas written from left to right, the substituents also include chemically equivalent substituents obtained when writing formulas from right to left.

The section headings used in this specification are for organizational purposes only and are not to be construed as limiting the subject matter described. All documents or portions of documents cited in this disclosure, including but not limited to patents, patent applications, articles, books, operating manuals, and treatises, are hereby incorporated by reference in their entirety.

Unless otherwise specified, all technical and scientific terms used herein have the standard meaning of the art to which the claimed subject matter belongs. In case there are multiple definitions for a term, the definitions herein control.

As used herein, the singular forms "a", "an", and "the" are understood to include plural referents unless the context clearly dictates otherwise. Furthermore, the term "comprising" is an open-ended limitation and does not exclude other aspects, i.e. it includes the content indicated by the invention.

Unless otherwise indicated, the present invention employs conventional methods of mass spectrometry, elemental analysis, and the various steps and conditions are referred to in the art by conventional procedures and conditions.

The present invention employs, unless otherwise indicated, standard nomenclature for analytical chemistry, organic synthetic chemistry and optics, and standard laboratory procedures and techniques. In some cases, standard techniques are used for chemical synthesis, chemical analysis, and light emitting device performance detection.

The compounds of the present invention may contain non-natural proportions of atomic isotopes on one or more of the atoms comprising the compounds. For example, compounds such as deuterium (2H) may be labeled with a radioisotope. All isotopic variations of the compounds of the present invention, whether radioactive or not, are intended to be encompassed within the scope of the present invention.

In the present invention, the number of "substitutions" may be one or more unless otherwise specified; when plural, it means two or more, for example, may be 2, 3 or 4. In addition, when the number of "substitutions" is plural, the "substitutions" may be the same or different. In the present invention, the "substituted" position may be any position unless otherwise specified.

In the present invention, as part of a group or other groups (e.g., as used in halogen-substituted alkyl groups and the like), the term "alkyl" is meant to include both branched and straight-chain saturated aliphatic hydrocarbon groups having the indicated number of carbon atoms. For example, C ₁ ～C ₂₀ Alkyl groups include straight or branched chain alkyl groups having 1 to 20 carbon atoms. As in "C ₁ ～C ₆ Alkyl "is defined to include groups having 1, 2, 3, 4, 5, or 6 carbon atoms in a straight or branched chain structure. For example, in the present invention, the C1-C6 alkyl groups are each independently methyl, ethyl, propyl, butyl, pentyl or hexyl; wherein propyl is C3 alkyl (including isomers such as n-propyl or isopropyl); butyl is C4 alkyl (including isomers such as n-butyl, sec-butyl, isobutyl, or tert-butyl); pentyl is C5 alkyl (including isomers such as n-pentyl, 1-methyl-butyl, 1-ethyl-propyl, 2-methyl-1-butyl, 3-methyl-1-butyl, isopentyl, t-pentyl or neopentyl); hexyl is C6 alkyl (including isomers such as n-hexyl or isohexyl).

The term "alkoxy" as used herein refers to an alkyl group as defined above, each attached via an oxygen bond (-O-).

In the present invention, the term "Cn-m aryl" as part of a group or other group refers to a monocyclic or polycyclic aromatic group having n to m ring carbon atoms (the ring atoms being carbon atoms only) having at least one carbocyclic ring with a conjugated pi-electron system. Examples of the above aryl unit include phenyl, naphthyl, indenyl, azulenyl, fluorenyl, phenanthryl, or anthracyl. In one embodiment, the aryl group is preferably a C6-14 aryl group, such as phenyl and naphthyl, more preferably phenyl.

In the present invention, the term "n-m membered heteroaryl" as part of a group or other group means an aromatic group having one or more (e.g., 1, 2, 3 and 4) heteroatoms selected from nitrogen, oxygen and sulfur, having from n to m ring atoms, said heteroaryl being a monocyclic, bicyclic, tricyclic or tetracyclic ring system, wherein at least one ring is an aromatic ring. Heteroaryl groups within the scope of this definition include, but are not limited to: acridinyl, carbazolyl, cinnolinyl, quinoxalinyl, pyrazolyl, indolyl, benzotriazole, furanyl, thienyl, benzothienyl, benzofuranyl, quinolinyl, isoquinolinyl, oxazolyl, isoxazolyl, pyrazinyl, pyridazinyl, pyridyl, pyrimidinyl, pyrrolyl, tetrahydroquinolinyl, imidazolyl, triazolyl, tetrazolyl, thiazolyl, isothiazolyl, furazanyl, thiadiazolyl, oxadiazolyl, pyridyl, pyrazinyl, pyridazinyl, pyrimidinyl, triazinyl, purinyl, pteridinyl, naphthyridinyl, quinazolinyl, phthalazinyl, imidazopyridinyl, imidazothiazolyl, imidazooxazolyl, benzothiazolyl, benzoxazolyl, benzimidazolyl, isoindolyl, indazolyl, pyrrolopyridinyl, thienopyridinyl, benzothiadiazolyl, benzoxadiazolyl, pyrrolopyrimidinyl, thienofuranyl. In one embodiment, as preferable examples of the "5-to 18-membered heteroaryl group", furyl, thienyl, pyrrolyl, imidazolyl, thiazolyl, pyrazolyl, oxazolyl, isoxazolyl, isothiazolyl, pyridyl, pyrimidinyl and carbazolyl groups are cited, and carbazolyl groups are more preferable.

The term Cn-Cm cycloalkyl as used herein refers to mono-or multicyclic alkyls having from n to m carbon atoms, such as 3-C10 cycloalkyl and C3-C6 cycloalkyl. Examples include adamantyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl and bicycloheptyl. In one embodiment, the C3-C10 cycloalkyl is preferably adamantyl or cyclohexyl.

The definition of a carbon number range for a group as described in the present invention means that any integer included in the definition, such as C, of carbon atoms ₁ ～C ₂₀ It is meant that the number of carbon atoms of the radical may be 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 or 20, C ₃ -C ₁₀ It is meant that the number of carbon atoms of the group may be 3, 4, 5, 6, 7, 8, 9 or 10, and so on for the other groups.

The above preferred conditions can be arbitrarily combined on the basis of not deviating from the common knowledge in the art, and thus, each preferred embodiment of the present invention can be obtained.

The reagents and materials used in the present invention are commercially available.

Compared with the prior art, the invention has the following beneficial effects:

the boron nitrogen compound introduces nitrogen atoms through extended conjugation, so that not only is fine adjustment of spectrum realized, but also the luminous efficiency is further improved. The boron nitride compound has a narrow spectrum, is used as a narrow spectrum luminescent material for preparing a luminescent layer of an organic electroluminescent device, and the prepared organic electroluminescent device realizes narrow spectrum TADF emission, has a half-peak width of less than 45nm and a luminescent peak position in a 500-560nm range, and ensures that the electroluminescent external quantum efficiency of the device is up to more than 30%.

Drawings

Fig. 1 is a schematic structural diagram of a vacuum evaporation type organic electroluminescent device provided by the invention, wherein 1 is an ITO anode, 2 is a first hole transport layer, 3 is a second hole transport layer, 4 is a light emitting layer, 5 is an electron transport layer, 6 is an electron injection layer, and 7 is a metal cathode.

FIG. 2 is an electroluminescent spectrum of a device using the compound BN-19, an emission peak of which is located at 519nm and a half-width of 29nm.

Detailed Description

The technical scheme of the invention is further described by the following specific embodiments. It will be apparent to those skilled in the art that the examples are merely to aid in understanding the invention and are not to be construed as a specific limitation thereof.

Synthetic example molecular structure:

the specific adopted raw materials are as follows:

the specific adopted raw material two molecules are as follows:

the specific adopted raw materials III and IV comprise the following molecules:

synthetic examples

The specific synthetic route of the invention is shown as follows

In the first step, starting material one (m=0 or 1 or 2) (6 mmol), starting material two 4.79g (15 mmol), cesium carbonate 5.90g (18 mmol) were added to 100ml of n, n-dimethylformamide, the mixture was bubbled with nitrogen for 10 minutes, and the system was heated to 160 degrees celsius and stirred for 12 hours. After the reaction system is cooled to room temperature, the reaction mixture is extracted by dichloromethane and water, the organic phase is dried by heating under vacuum, and then the precursor BN-n-I is obtained by column chromatography purification.

Secondly, when m=0, the precursor BN-n-I can be equal to the precursor BN-n-II without the reaction of the step;

when m=1, the precursor BN-n-I (4 mmol), raw material three (5 mmol), potassium carbonate 1.10g (8 mmol) and H are added ₂ O (12 mL) was added to tetrahydrofuran (80 mL), the mixture was bubbled with nitrogen for 10 minutes, and 116mg of tetrakis (triphenylphosphine) palladium (0.10 mmol) was added under high flow nitrogen. The mixture was heated to reflux and stirred for 12 hours. After the reaction system is cooled to room temperature, extracting the reaction mixture by using dichloromethane and water, heating and spin-drying the organic phase under vacuum, and purifying by column chromatography to obtain a precursor BN-n-II;

when m=2, the precursor BN-n-I (5 mmol), raw material three (5 mmol), potassium carbonate 1.38g (10 mmol) and H ₂ O (12 mL) was added to tetrahydrofuran (80 mL), the mixture was bubbled with nitrogen for 10 minutes, and 116mg of tetrakis (triphenylphosphine) palladium (0.10 mmol) was added under high flow nitrogen. The mixture was heated to reflux and stirred for 12 hours. After the reaction system is cooled to room temperature, the reaction mixture is extracted by dichloromethane and water, the organic phase is dried by heating under vacuum, and then the precursor pre-BN-n-II is obtained by column chromatography purification.

The precursor pre-BN-n-II (4 mmol), starting material four (5 mmol), potassium carbonate 1.10g (8 mmol) and H are then added ₂ O (12 mL) was added to tetrahydrofuran (80 mL), the mixture was bubbled with nitrogen for 10 minutes, and 116mg of tetrakis (triphenylphosphine) was added under high flow of nitrogen) Palladium (0.10 mmol). The mixture was heated to reflux and stirred for 12 hours. After the reaction system is cooled to room temperature, the reaction mixture is extracted by dichloromethane and water, the organic phase is dried by heating under vacuum, and then the precursor BN-n-II is obtained by column chromatography purification.

Third, 3.10mL of a pentane solution (1.30M, 4 mmol) of t-butyllithium was slowly dropped into a solution of BN-n-II (2 mmol) in t-butylbenzene (60 mL) at 0℃under nitrogen atmosphere, and then heated to 60℃to react for 2 hours. Then cooling to-40 ℃, slowly adding 1.00g (4 mmol) of boron tribromide, heating to room temperature and stirring for 0.5 hour. 1.03g (8 mmol) of N, N-diisopropylethylamine was added thereto after cooling to 0℃and the reaction was continued at 140℃for 6 hours, followed by stopping the reaction. After the reaction system was cooled to room temperature, 5mL of methanol and 5mL of water were quenched for reaction, the reaction mixture was extracted with dichloromethane and water, the organic phase was dried by heating under vacuum, and then purified by column chromatography to give the objective product BN-n. The data obtained for the target compounds are shown in Table 1.

Experimental details of the synthetic examples are illustrated by the compound BN-30:

In the first step, 1.36g of Compound A1 (6 mmol), 4.79g of Compound B1 (15 mmol), and 5.90g (18 mmol) of cesium carbonate were added to 100mL of N, N-dimethylformamide, and the mixture was bubbled with nitrogen for 10 minutes, and the system was heated to 160℃and stirred for 12 hours. After the reaction system was cooled to room temperature, the reaction mixture was extracted with dichloromethane and water, the organic phase was dried by heating under vacuum, and then purified by column chromatography to give 4.46g of the precursor BN-30-I (yield 90%).

In a second step, 3.30g of the precursor BN-30-I (4 mmol), 1.17g of compound C6 (5 mmol), 1.10g of potassium carbonate (8 mmol) and H are reacted ₂ O (12 mL) was added to tetrahydrofuran (80 mL), the mixture was bubbled with nitrogen for 10 minutes, and 116mg of tetrakis (triphenylphosphine) palladium (0.10 mmol) was added under high flow nitrogen. The mixture was heated to reflux and stirred for 12 hours. After the reaction system was cooled to room temperature, the reaction mixture was extracted with dichloromethane and water, the organic phase was dried by heating under vacuum, and then purified by column chromatography to give 3.48g of the precursor BN-30-II (yield 93%).

In the third step, 3.10mL of a pentane solution (1.30M, 4 mmol) of t-butyllithium was slowly dropped into a solution (60 mL) of 1.87g of BN-30-II (2 mmol) in t-butylbenzene at 0℃under nitrogen atmosphere, and then heated to 60℃to react for 2 hours. Then cooling to-40 ℃, slowly adding 1.00g (4 mmol) of boron tribromide, heating to room temperature and stirring for 0.5 hour. After cooling to 0℃1.03g (8 mmol) of N, N diisopropylethylamine was added and the reaction was continued at 140℃for 6 hours and stopped. After the reaction system was cooled to room temperature, the reaction was quenched with 5mL of methanol and 5mL of water, the reaction mixture was extracted with dichloromethane and water, the organic phase was dried by heating under vacuum, and then purified by column chromatography to give the objective product, 0.87g BN-30 (yield 48%).

The product was characterized in that the elemental analysis used a test instrument of Vario Micro Cube from Agilent, U.S.A., test element type C, H, N. The instrument used for mass spectrometry is a triple quadrupole mass spectrometer in tandem with ultra high performance liquid chromatography in U.S. Thermo Fisher TSQ Endura.

TABLE 1 summary of synthetic example product data

The following are some of the molecular structures of materials involved in some representative embodiments of organic electroluminescent devices:

the molecules of the compounds involved in the comparative examples are as follows:

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the preparation process of the organic electroluminescent device of the embodiment is as follows:

(1) And (3) substrate processing: the transparent ITO glass is used as a substrate material for preparing devices, firstly, the transparent ITO glass is treated by 5% ITO washing liquid for 30min, then distilled water (2 times), acetone (2 times) and isopropanol (2 times) are sequentially washed by ultrasonic, and finally, the ITO glass is stored in the isopropanol. Before each use, the surface of the ITO glass is carefully wiped by acetone cotton balls and isopropanol cotton balls, and after the isopropanol is washed, the ITO glass is dried, and then is treated by plasma for 5min for standby. The subsequent preparation of the device is completed by combining spin coating and vacuum evaporation process.

(2) Hole injection layer or hole transport layer preparation: adopting vapor deposition process to prepare hole transport layer or hole injection layer, when vacuum degree of vacuum vapor deposition system reaches 5×10 ^-4 Starting vapor deposition when Pa is lower, monitoring the deposition rate by a Saint film thickness instrument, and sequentially depositing a hole transport layer or a hole injection layer on the surface of the ITO electrode by utilizing a vacuum vapor deposition process, wherein the deposition rate of a hole transport layer material or a hole injection layer material is as follows

(3) Preparing a light-emitting layer: the luminous layer is prepared by adopting the vapor plating process, when the vacuum degree of the vacuum vapor plating system reaches 5 multiplied by 10 ^- ⁴ Starting vapor deposition when Pa is lower, monitoring the deposition rate by a Saint film thickness instrument, and depositing a luminescent layer on the hole transport layer by using a vacuum vapor deposition process, wherein the deposition rate of the luminescent layer material is as follows

(4) Preparation of an electron transport layer, an electron injection layer and a metal electrode: an electron transport layer, an electron injection layer and a metal electrode are prepared by adopting an evaporation process, and when the vacuum degree of a vacuum evaporation system reaches 5 multiplied by 10 ^-4 And starting evaporation when Pa is lower, monitoring the deposition rate by using a Saint film thickness instrument, and sequentially depositing an electron transport layer, an electron injection layer and a metal electrode on the light-emitting layer by using a vacuum evaporation process. Wherein the deposition rate of the electron transport layer material isThe deposition rate of the electron injection layer isThe deposition rate of the metal electrode is +.>

The structure of the organic electroluminescent device of this embodiment is shown in fig. 1, and the structure sequentially comprises an ITO anode 1, a first hole transport layer 2, a second hole transport layer 3, a light emitting layer 4, an electron transport layer 5, an electron injection layer 6, and a metal cathode 7 from bottom to top.

Device examples 1 to 6

The organic electroluminescent device in device examples 1 to 6 has a structure as shown in fig. 1, in which HTL-1 was used as the material of the first hole transport layer 2, HTL-2 was used as the material of the second hole transport layer 3, H1-56 (content of 70 wt%) + TRZ-78 (content of 29 wt%) was used as the host material in the light-emitting layer 4, BN-n was used as the doped light-emitting material (content of 1 wt%) (BN-n represents any of the light-emitting materials involved in the device examples), ETL was used as the material of the electron transport layer 5, liF was used as the electron injection layer 6, and Al was used as the metal cathode 7. The organic electroluminescent device structure of device example 1 was [ ITO/HTL-1 (50 nm)/HTL-2 (5 nm)/70 wt% H1-56+29wt% TRZ-78+1wt% BN-n (30 nm)/ETL (30 nm)/LiF (1 nm)/Al (100 nm) ].

The current, voltage, brightness, luminescence spectrum and other characteristics of the device were synchronously tested using a Photo Research PR 655 spectral scanning luminance meter and a Keithley K2400 digital source meter system. The performance test of the device was performed at room temperature under ambient atmosphere. The External Quantum Efficiency (EQE) of the device is calculated from the current density, brightness and electro-spectral combined with the visual function in the case of the light emission as a langerhans distribution.

The performance data for device examples 1-6 are shown in Table 2, and device lifetime (T95, hours) in Table 2 refers to an initial device luminance of 10000cd/m ² When the brightness of the device drops to 95% of the original brightness (i.e., the device brightness drops to 9500 cd/m) ² Time) is required.

TABLE 2

FIG. 2 is an electroluminescent spectrum of a device using the compound BN-19, which is found to have an electroluminescent peak position of 519nm and a half-width of 29nm.

Comparative device examples D-1 to D-21

The organic electroluminescent device in device examples 1 to 50 was structured as shown in fig. 1, HTL-1 was used as the material of the first hole transport layer 2, HTL-2 was used as the material of the second hole transport layer 3, H1 to 56 (content 70 wt%) + TRZ to 78 (content 29 wt%) was used as the host material, R-m was used as the doped luminescent material (content 1 wt%) (m=1 to 21), ETL was used as the material of the electron transport layer 5, liF was used as the electron injection layer 6, and Al was used as the metal cathode 7 in the luminescent layer 4. The organic electroluminescent device structure of device example 1 was [ ITO/HTL-1 (50 nm)/HTL-2 (5 nm)/70 wt% H1-56+29wt% TRZ-78+1wt% R-m (30 nm)/ETL (30 nm)/LiF (1 nm)/Al (100 nm) ].

The performance data of the comparative device examples are shown in Table 3, and the device lifetime (T95, hours) in Table 3 refers to an initial device luminance of 10000cd/m ² When the brightness of the device drops to 95% of the original brightness (i.e., the device brightness drops to 9500 cd/m) ² Time) is required.

TABLE 3 Table 3

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By comparing the performance data of the organic electroluminescent devices listed in tables 2 and 3, it can be seen that the organic electroluminescent device provided by the application shows high efficiency at high brightness and also has good device stability, which indicates that the organic electroluminescent device of the application has the advantages of high external quantum efficiency and good stability.

The applicant states that the boron nitrogen compounds of the present application, and their preparation methods and applications, are illustrated by the above examples, but the present application is not limited to, i.e. does not mean that the present application must be practiced in dependence upon the above examples. It should be apparent to those skilled in the art that any modification of the present application, equivalent substitution of selected raw materials, addition of auxiliary components, selection of specific modes, etc. fall within the scope of the present application and the scope of disclosure.

Claims

1. A boron nitride compound, characterized in that the boron nitride compound has a structure represented by formula I:

R ^a independently at each occurrence deuterium, fluorine, CN, C1-C12 alkyl, C1-C12 alkoxy, C3-C12 cycloalkyl, C6-C14 aryl, substituted with one or more R ^b Substituted C6-C14 aryl, 5-to 18-membered heteroaryl, substituted with one or more R ^b Substituted 5-to 18-membered heteroaryl, diphenylamino, or substituted with oneOne or more R ^b Substituted diphenylamino groups;

2. The boron nitride according to claim 1, wherein said R ¹ And R is ² Independently is H, deuterium, C1-C20 alkyl, C3-C10 cycloalkyl, C6-C18 aryl or 5-to 24-membered heteroaryl;

preferably, said R ¹ And R is ² Is a C6-C12 aryl or a 5-to 18-membered heteroaryl;

preferably, R ⁰⁵ And R is ⁰⁶ Independently selected from C6-C12 aryl;

the R is ¹ And R is ² Independently is H, deuterium, fluorine, methyl, ethyl, n-propyl, isopropyl, n-butyl, t-butyl, hexyl, octyl, decyl, phenyl, pyridyl, biphenyl, 2-methyl-phenyl, 2, 6-dimethylphenyl, 4-methyl-phenyl, 4-ethyl-phenyl, 4-propyl-phenyl, 4-isopropylphenyl, 4-n-butylphenyl, fluorophenyl, a, Wherein the wavy line represents the attachment site of the group.

3. The boron nitride compound according to claim 1 or 2, wherein the boron nitride compound is any one of the following compounds BN-1 to BN-32:

4. a method for producing a boron nitrogen compound according to any one of claims 1 to 3, comprising the steps of:

(2) When m=0, the compound BN-n-I is equivalent to the compound BN-n-II without performing the reaction of this step, and step (2) is directly skipped to perform step (3);

①

②

③

5. the process according to claim 4, wherein the reaction of step (1) is carried out in the presence of an alkaline substance;

preferably, the alkaline substance in step (1) is cesium carbonate;

preferably, the molar ratio of the first raw material to the second raw material in the step (1) is 2-6:1;

preferably, the molar ratio of the alkaline substance to the second raw material is 3-8:1;

preferably, the solvent of the reaction of step (1) is N, N-dimethylformamide;

preferably, the temperature of the reaction in the step (1) is 120-160 ℃ and the time is 8-24 hours;

preferably, the molar ratio of the compound BN-n-I to the raw material III in the reaction (1) in the step (2) is 1:1-4;

Preferably, the molar ratio of the compound BN-n-I to the raw material III in the reaction (2) in the step (2) is 1-4:1;

preferably, the molar ratio of the compound pre-BN-n-II to the raw material IV in the reaction (3) in the step (2) is 1:1-4;

preferably, the reactions (1), (2), (3) of step (2) are carried out in the presence of a catalyst;

preferably, the catalyst in the reactions (1), (2) and (3) in the step (2) is tetrakis (triphenylphosphine) palladium;

preferably, the catalyst in the reaction (1) in the step (2) is 0.1% -10% of the molar amount of the compound BN-n-I;

preferably, the catalyst in the reaction (2) in the step (2) is 0.1% -10% of the three-mole amount of the raw material;

preferably, the catalyst in the reaction (3) in the step (2) is 0.1% -10% of the molar amount of the compound pre-BN-n-II;

preferably, the reactions (1), (2), (3) of step (2) are carried out in the presence of a weakly basic substance;

preferably, the weakly basic material in the reactions (1), (2) and (3) in the step (2) is potassium carbonate;

preferably, the molar ratio of the weakly basic substance to the compound BN-n-I in the reaction (1) in the step (2) is 2-8:1;

preferably, the molar ratio of the weakly basic substance to the compound III in the reaction (2) in the step (2) is 2-8:1;

preferably, the molar ratio of the weakly basic material to the compound pre-BN-n-II in the reaction (3) in step (2) is from 2 to 8:1;

Preferably, the solvent of the reactions (1), (2) and (3) in the step (2) is a mixed solution of tetrahydrofuran and water;

preferably, the reaction temperature of the reactions (1), (2) and (3) in the step (2) is 60-100 ℃, and the reaction time is independently 6-24 hours;

preferably, the lithiation stage in the lithiation-boronation-cyclization reaction of step (3) is performed in the presence of an alkyllithium reagent;

preferably, the alkyl lithium reagent is t-butyl lithium;

preferably, the stage of boriding in the lithiation-boriding-cyclisation reaction of step (3) is carried out in the presence of a boron-containing reagent;

preferably, the boron-containing reagent is boron tribromide;

preferably, the cyclisation stage in the lithiation-boronation-cyclisation reaction of step (3) is carried out in the presence of an alkaline substance;

preferably, the basic substance is N, N-diisopropylethylamine;

preferably, the molar ratio of the compound BN-n-II to the alkyl lithium reagent in the step (3) is 1:2-4;

preferably, the molar ratio of the compound BN-n-II to the boron-containing reagent in the step (3) is 1:2-6;

preferably, the molar ratio of the compound BN-n-II to the alkaline substance in the step (3) is 1:2-8;

preferably, the solvent of the reaction of step (3) is tert-butylbenzene;

preferably, the lithiation stage in the lithiation-boronation-cyclization reaction in the step (3) is performed at 0-60 ℃, and the reaction time of the lithiation stage is 2-6 hours;

Preferably, the step (3) is carried out at-40-25 ℃ in the boride stage in the lithiation-boride-cyclization reaction, and the reaction time of the boride stage is 0.5-2 hours;

preferably, the cyclizing stage in the lithiation-boronation-cyclizing reaction in step (3) is carried out at 0 to 140 ℃ and the reaction time of the cyclizing stage is 6 to 12 hours.

6. An organic electroluminescent composition, characterized in that it comprises the boron nitride compound according to any one of claims 1 to 4 and a host material as doping materials;

preferably, the host material is a material having an electron transport ability and/or a hole transport ability and having a triplet excited state energy higher than or equal to that of the dopant material;

wherein R is ^1H And R is ^2H Independently any of the following groups:

wherein R is ^aH And R is ^bH H, C independently ₁ -C ₂₀ Alkyl, C ₁ -C ₂₀ Alkoxy, C ₆ -C ₂₀ Aryl, C ₁ -C ₂₀ Alkyl substituted C ₆ -C ₂₀ Aryl or C ₁ -C ₂₀ Alkoxy substituted C ₆ -C ₂₀ Aryl, number represents the attachment of a groupA site;

preferably, the organic electroluminescent composition preferably contains 0.3 to 30.0wt% of the boron-nitrogen compound as described above as a doping material, and the remaining 99.7 to 70.0wt% of the composition is a host material composed of 1 to 2 compounds having structures of formulae (H-1) to (H-6);

Preferably, the host material contains 2 compounds having the structures of formulae (H-1) to (H-6) in a weight ratio of 1:5 to 5:1;

preferably, the host material in the organic electroluminescent composition is one or two of the compounds H1-1 to H1-427;

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preferably, the organic electroluminescent composition contains 2 compounds H1-1 to H1-427 as main materials, and the weight ratio of the two compounds is 1:5 to 5:1;

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wherein asterisks represent the attachment site of the group;

preferably, the weight ratio of the Trz1-A, trz2-A, trz3-A, trz4-A, trz5-A or Trz6-A compound to the H-1, H-2, H-3, H-4, H-5 or H-6 compound in the main material is 1:20-20:1;

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preferably, the weight ratio between the compound represented by the formulas TRZ-1 to TRZ-80 and the carbazole or carboline derivative in the host material is 1:20 to 20:1.

7. An organic electroluminescent material, characterized in that it comprises the boron-nitrogen compound according to any one of claims 1 to 3 or the organic electroluminescent composition according to claim 6.

8. An organic electroluminescent device comprising an anode and a cathode and an organic thin film layer disposed between the anode and the cathode, the organic thin film layer comprising the boron-nitrogen compound of any one of claims 1-3 or the organic electroluminescent composition of claim 6.

9. The organic electroluminescent device according to claim 8, wherein the organic thin film layer comprises a light emitting layer, an optional hole injection layer, an optional hole transport layer, an optional electron injection layer, wherein at least one of the light emitting layer, the electron injection layer, the electron transport layer, the hole injection layer comprises the boron-nitrogen compound of any one of claims 1 to 3 or the organic electroluminescent composition of claim 6;

preferably, the material of the light-emitting layer in the organic electroluminescent device comprises the boron-nitrogen compound according to any one of claims 1 to 3 or the organic electroluminescent composition according to claim 6;

preferably, the organic electroluminescent device further comprises an optional hole blocking layer, an optional electron blocking layer and an optional capping layer.

10. Use of an organic electroluminescent device according to claim 8 or 9 in an organic electroluminescent display or an organic electroluminescent illumination source.