A five-membered heterocyclic ring-centered double-boron polycyclic compound and application thereof

Abstract

The application belongs to the technical field of organic electroluminescent materials, and relates to a double-boron polycyclic compound with a five-membered heterocycle as a center and application thereof. The double-boron polycyclic compound with a five-membered heterocycle as a center has good stability as a blue light emitting material, and has a smaller singlet-triplet energy difference, a stronger multiple resonance type thermal activated delayed fluorescence effect, and the like, so that the emission spectrum is narrowed when the double-boron polycyclic compound is applied to OLED, and the efficiency, color purity and other performances of the organic electroluminescent device are improved, and the double-boron polycyclic compound can be widely applied to OLED light emitting devices and display devices.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of organic electroluminescent materials, and relates to a double-boron polycyclic compound with a five-membered heterocycle as a center and application thereof. BACKGROUND

[0002] Organic electroluminescent elements (OLEDs) have developed rapidly as a new type of solid-state light-emitting technology and have gradually become mainstream display technology. An organic electroluminescent element usually has a structure including 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. Under the action of an applied electric field, holes are injected from the anode into the organic layer, and electrons are injected from the cathode into the organic layer. When these injected holes and electrons meet in the light-emitting layer, excitons are formed, and when the excitons retransition to the ground state, energy is released to emit light.

[0003] With the iterative development of new display technology, to meet the display effect of ultra-high definition, the display standard (BT.2020) has extremely high requirements for the color purity of the device, with a blue light CIEy=0.046. If this index requirement is to be met, the emission spectrum half-width of the material must be narrow enough. However, due to the influence of molecular vibration relaxation and Stokes shift, the emission spectrum half-width of conventional fluorescent materials is generally >50 nm, resulting in a deviation of the color coordinates from the target value of the blue light of the BT.2020 standard.

[0004] MR-TADF materials can make holes and electrons interact with each other in the molecules of the material to achieve resonance effect, reduce Stokes shift, and narrow the spectrum. At the same time, such compounds have thermal activity delay characteristics, can utilize both singlet and triplet state energy, and can theoretically achieve 100% internal quantum efficiency to achieve high efficiency. However, the conditions for realizing a blue light MR-TADF material with multiple resonance effect thermal activity delay fluorescence are harsh, as it is necessary to ensure a wide band gap, a small enough singlet and triplet state energy level difference, and the realization of resonance effect. How to construct a new type of compound to obtain an MR-TADF material is a hot and difficult point in the industry. Therefore, it is of great significance to construct a blue light MR-TADF material with a wide band gap, a low singlet and triplet state energy level difference, and the realization of resonance effect to improve the color purity of blue light devices. SUMMARY

[0005] To solve the above technical problems, the application provides a five-membered heterocyclic ring-centered double-boron polycyclic compound and application thereof as MR-TADF light-emitting material on an OLED device.The five-membered heterocyclic ring-centered double-boron polycyclic compound as a blue light-emitting material has good stability, a smaller singlet-triplet energy difference, a stronger multi-resonance thermal activated delayed fluorescence effect, and narrow emission spectrum when applied to an OLED, thereby improving the efficiency, color purity and other performances of an organic electroluminescent device and being widely applicable to OLED light-emitting devices and display devices.

[0006] To achieve the technical purposes of the application, in one aspect, the application provides a compound having a structure as shown in formula (I) or formula (II),

[0007] ;

[0008] X in the formula (I) and the formula (II) is selected from one of CR1R2, NR3, adamantyl, O, S and Se;

[0009] Y1 and Y2 in the formula (I) and the formula (II) are selected from one of NR4, O, S and Se;

[0010] Ar1-Ar4 in the formula (I) and the formula (II) are selected from hydrogen, deuterium, C1-C5 alkyl, substituted or unsubstituted amine group, substituted or unsubstituted C6-C30 aryl and substituted or unsubstituted C6-C30 heteroaryl.

[0011] Further, in the compound provided by the application, R1 and R2 in CR1R2 are methyl or phenyl; R3 in NR3 is substituted or unsubstituted C6-C30 aryl or substituted or unsubstituted C6-C30 heteroaryl; and R4 in NR4 is substituted or unsubstituted C6-C30 aryl or substituted or unsubstituted C6-C30 heteroaryl.

[0012] The C1-C5 alkyl is selected from one of methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, n-pentyl, iso-pentyl and neopentyl;

[0013] The substituted or unsubstituted amine group is selected from one of the following structures,

[0014] ;

[0015] The substituted or unsubstituted C6-C30 aryl is selected from one of the following structures,

[0016] ;

[0017] The substituted or unsubstituted C6-C30 heteroaryl is selected from one of the following structures,

[0018] .

[0019] Further, the compound provided by the present application has the structure as shown in the following,

[0020] .

[0021] The formula (II) has the structure as shown in the following,

[0022] .

[0023] Specifically, all hydrogen atoms in the compound can be arbitrarily deuterated.

[0024] Further, the compound provided by the present application has the structure as shown in the following,

[0025]

[0026]

[0027]

[0028]

[0029]

[0030]

[0031]

[0032]

[0033]

[0034]

[0035]

[0036]

[0037]

[0038]

[0039]

[0040]

[0041]

[0042]

[0043]

[0044]

[0045]

[0046]

[0047]

[0048]

[0049]

[0050]

[0051]

[0052]

[0053]

[0054]

[0055]

[0056]

[0057]

[0058]

[0059]

[0060]

[0061]

[0062] ;

[0063] wherein D represents a hydrogen atom replaced with deuterium.

[0064] In another aspect, the present application claims the use of the above-mentioned compound in an organic electroluminescence device.

[0065] In another aspect, the present application claims the use of the above-mentioned compound in an organic electroluminescence device.

[0066] In another aspect, the present application claims an organic electroluminescence device comprising an anode layer, a cathode layer and an organic thin film layer between the anode layer and the cathode layer, the organic thin film layer comprising a hole injection layer, a hole transport layer, an electron blocking layer, a light emitting layer, a hole blocking layer, an electron transport layer and an electron injection layer, the light emitting layer comprising the above-mentioned compound.

[0067] Compared with the prior art, the technical solution provided by the present application has at least the following beneficial effects or advantages:

[0068] (1) In the present application, two boron atoms are introduced on both sides of the five-membered heterocyclic molecule, and the two symmetric B atoms form covalent bonds with N, O, S and Se to construct a polycyclic compound, so that the compound has a large twist while ensuring a high singlet and triplet energy, a suitable HOMO and LUMO energy level, and a small energy difference between the singlet and triplet states. The HOMO energy level of the compound prepared by the present application is between -4.816 and 5.669 eV, and the LUMO energy level is between -1.315 and -1.928. Compared with the existing luminescent material BD01, the present application has a wider band gap and better stability; the singlet-triplet energy difference (△Est) of the compound of the present application is 0.017-0.219, which is smaller than that of BD01.

[0069] (2) In the double-boron polycyclic compound with a five-membered heterocyclic center, the five-membered heterocyclic center molecule participates in conjugation, and the charge distribution in the molecule is improved by changing the heteroatoms, so that the compound has a strong multiple resonance thermally activated delayed fluorescence (MR-TADF) effect. When applied as a luminescent material in OLED, the emission spectrum is narrowed, and the efficiency, color purity and other properties of the organic electroluminescence device are improved, and the compound can be widely applied to OLED light-emitting devices and display devices. In particular, compound 30 is used as a blue light host material in an OLED device, and the external quantum efficiency (EQE) is improved by 39.2%, and the electro-optical conversion efficiency is better. BRIEF DESCRIPTION OF DRAWINGS

[0070] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed in the following embodiment or prior art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and those skilled in the art can also obtain other drawings according to these drawings without creative labor.

[0071] Figure 1 Figure 1 is a structural schematic diagram of an organic electroluminescent element. In the figure, 1 is a substrate, 2 is an anode layer, 3 is a hole injection layer, 4 is a hole transport layer, 5 is an electron blocking layer, 6 is a light-emitting layer, 7 is a hole blocking layer, 8 is an electron transport layer, 9 is an electron injection layer, and 10 is a cathode layer. DETAILED DESCRIPTION

[0072] The technical solutions of the present application will be described below in conjunction with examples. However, the present application is not limited to the following examples. The experimental methods and detection methods described in each example are all conventional methods unless otherwise specified. The reagents and materials described are all commercially available unless otherwise specified. The percentages in the following examples are all mass percentages unless otherwise specified.

[0073] Example 1

[0074] This example provides the synthesis of compound 1 (having a structure as shown in formula (I), wherein X is CR1R2, R1 and R2 are both methyl, Y1 and Y2 are both O, and Ar1-Ar4 are all C4 alkyl groups). The synthesis route is shown below and specifically includes the following steps:

[0075]

[0076] S1: Under nitrogen protection, raw material 1 (31.02 g, 100 mmol), raw material 2 (41.21 g, 50 mmol), potassium carbonate (18.83 g, 136.50 mmol), and DMF (310 mL) were added to a reaction bottle, followed by the addition of Pd2(dba)3 (1.66 g, 1.82 mmol) and X-Phos (1.73 g, 3.64 mmol), and heating to 120°C for 4h. After the reaction was completed, the system was cooled to room temperature and poured into water to generate a white precipitate, which was filtered. The precipitate was washed with water and ethanol in sequence. Finally, the silica gel column was passed through and recrystallized to obtain intermediate 1-1 (37.59 g, with a yield of 48%).

[0077] S2: Under nitrogen protection, intermediate 1-1 (31.33 g, 40.0 mmol) and dichloromethane (310 mL) were sequentially added to a three-necked flask equipped with a condenser, and then the system was cooled to 0-5°C, followed by the slow dropwise addition of boron tribromide (11.03 g, 44.0 mmol). After the reaction was completed, the system was poured into a large amount of ice water and filtered. The filter cake was washed with water and ethanol in sequence, and finally the silica gel column was passed through and recrystallized to obtain intermediate 1-2 (26.58 g, with a yield of 88%).

[0078] S3: Under nitrogen protection, into a three-necked flask equipped with a condenser, sequentially added intermediate 1-2 (22.66 g, 30.0 mmol), o-dichlorobenzene (50 mL), then slowly added boron tribromide (45.09 g, 180 mmol), heated to 150-160 °C for 8 h. After the reaction was completed, the system was cooled to room temperature. A large amount of water was added, and white precipitate was generated, which was filtered. The filter cake was washed with water, ethanol, and finally passed through a silica gel column and recrystallized to obtain compound 1 (10.41 g, yield 45%).

[0079] The characterization results of compound 1 are as follows: HRMS: found: 771.4537 [M+H] + ; accurate mass: 771.4545. C 55 H 56 B2O2 (%) calculated: C, 85.72%; H, 7.32%; B, 2.81%; O, 4.15%; found: C, 85.66%; H, 7.36%; B, 2.85%; O, 4.13%.

[0080] Example 2

[0081] This example provides the synthesis of compound 3 (having a structure as shown in formula (I), wherein X is CR1R2, R1 and R2 are both methyl, Y1 and Y2 are both O, and Ar1-Ar4 are all C4 alkyl groups). The synthesis route is shown below, and the synthesis method refers to the synthesis of compound 1, with the difference being that in S1, the raw material 3 is replaced by raw material 2, and compound 3 (31.70 g, yield 41%) is synthesized.

[0082]

[0083] The characterization results of compound 3 are as follows: LC-MS: found: 761.3789 [M+H] + ; accurate mass: 761.3796. C 52 H 50 O2B2S (%) calculated: C, 82.11%; H, 6.63%; O, 4.21%; B, 2.84%; S, 4.21%; found: C, 82.16%; H, 6.61%; O, 4.28%; B, 2.78%; S, 4.17%.

[0084] Example 3

[0085] The present example provides a synthesis of compound 13 (having a structure as shown in formula (I), wherein X is CR1R2, R1, R2 are both methyl, Y1, Y2 are both NR4, R4 is unsubstituted phenyl, Ar1~Ar4 are all C4 alkyl), the synthetic route is shown below, and specifically comprises the following steps:

[0086]

[0087] S1: Under nitrogen protection, raw material 1 (31.02 g, 100 mmol), raw material 4 (26.71 g, 50.0 mmol), potassium carbonate (18.83 g, 136.50 mmol) and DMF (310 mL) were added into a reaction bottle, and then Pd2(dba)3 (1.66 g, 1.82 mmol), X-Phos (1.73 g, 3.64 mmol) were added and heated to 120°C for 4h. After the reaction was completed, it was cooled to room temperature, poured into water, and a white precipitate was generated, which was filtered. The precipitate was washed with water and ethanol in sequence. Finally, it was subjected to silica gel column and recrystallization to obtain intermediate 13-1 (62.46 g, with a yield of 69%).

[0088] S2: Under nitrogen protection, intermediate 13-1 (18.11 g, 20.0 mmol) and o-dichlorobenzene (50 mL) were sequentially added into a three-necked flask equipped with a condenser, and then boron tribromide (30.06 g, 120 mmol) was slowly added dropwise, and the mixture was heated to 150°C~160°C for 8h. After the reaction was completed, the system was cooled to room temperature. A large amount of water was added, and a white precipitate was generated, which was filtered. The filter cake was washed with water and ethanol in sequence, and finally subjected to silica gel column and recrystallization to obtain compound 13 (7.55 g, with a yield of 41%).

[0089] The obtained sample was characterized, and the results were as follows: HRMS: measured value: 921.5487 [M+H]+; accurate mass: 921.5490. 67 H 66 B2N2 (%) calculated value: C, 87.39%; H, 7.22%; B, 2.35; N, 3.04; measured value: C, 87.42%; H, 7.24%; B, 2.31; N, 3.03.

[0090] Example 4

[0091] The present example provides a synthesis of compound 14 (having a structure as shown in formula (I), wherein X is O, Y1, Y2 are both NR4, R4 is unsubstituted phenyl, Ar1~Ar4 are all C4 alkyl), the synthetic route is shown below, and the synthesis method refers to the synthesis of compound 13, with the difference that in S1, raw material 5 is replaced by raw material 4, and compound 14 (33.41 g, with a yield of 38%) is synthesized.

[0092]

[0093] Compound 14 was characterized by LC-MS: measured value: 895.4977 [M+H] + ; accurate mass: 895.4970. C 58 H 56 B2N2O (%) calculated value: C, 85.91%; H, 6.76%; B, 2.42%; N, 3.13%; O, 1.79%; found value: C, 85.95%; H, 6.77%; B, 2.48%; N, 3.17%; O, 1.63%.

[0094] Example 5

[0095] This example provides the synthesis of compound 22 (having a structure as shown in formula (I), wherein X is O, Y1, Y2 are both NR4, R4 is phenyl substituted with methyl, and Ar1~Ar4 are all H), the synthetic route is shown below, and the synthetic method refers to the synthesis of compound 13, except that in S1, raw material 1 is replaced by raw material 6, and raw material 4 is replaced by raw material 7, to synthesize compound 22 (7.88g, yield 41%).

[0096]

[0097] The obtained sample was characterized by HRMS: measured value: 755.3400 [M+H] + ; accurate mass: 755.3405. C 54 H 40 B2N2O (%) calculated value: C, 85.96%; H, 5.34%; N, 3.71%; O, 2.12%; found value: C, 86.02%; H, 5.31%; N, 3.64%; O, 2.18%.

[0098] Example 6

[0099] This example provides the synthesis of compound 47 (having a structure as shown in formula (I), wherein X is S, Y1, Y2 are both NR4, R4 is heteroaryl, and Ar1~Ar4 are all C4 alkyl), the synthetic route is shown below, and the synthetic method refers to the synthesis of compound 13, except that in S1, raw material 4 is replaced by raw material 8, to synthesize compound 47 (7.65g, yield 44%).

[0100]

[0101] The obtained sample was characterized by HRMS: measured value: 1245.6144 [M+H]+ Exact mass: 1245.6150 C 88 H 70 D4B2N4S (%) Calc: C, 84.88%; H, 6.31%; N, 4.50%; S, 2.57%; B, 1.74%; Found: C, 84.80%; H, 6.34%; N, 4.60%; S, 2.50%; B, 1.67%.

[0102] Example 7

[0103] This example provides the synthesis of compound 61 (having the structure as shown in formula (I), wherein X is NR3, R3 is unsubstituted phenyl, Y1, Y2 are both O, Ar1~Ar4 are all C4 alkyl), the synthetic route is shown below, the synthetic method refers to the synthesis of compound 1, the difference is that the raw material 2 is replaced by the raw material 9 in S1, and compound 61 (43.27g, the yield is 52%) is synthesized.

[0104]

[0105] The characterization results of compound 61 are as follows: LC-MS: measured value: 820.4487 [M+H] + Exact mass: 820.4497 C 58 H 56 B2NO2 (%) Calc: C, 84.99%; H, 6.76%; B, 2.64%; N, 1.71%; O, 3.90%; Found: C, 84.86%; H, 6.87%; B, 2.66%; N, 1.77%; O, 3.84%.

[0106] Example 8

[0107] This example provides the synthesis of compound 62 (having the structure as shown in formula (I), wherein X is NR3, R3 is unsubstituted phenyl, Y1, Y2 are both S, Ar1~Ar4 are all C4 alkyl), the synthetic route is shown below, the synthetic method refers to the synthesis of compound 13, the difference is that the raw material 4 is replaced by the raw material 10 in S1, and compound 62 (38.46g, the yield is 46%) is synthesized.

[0108]

[0109] The characterization results of compound 62 are as follows: LC-MS: measured value: 852.8339 [M+H] + Exact mass: 852.8330 C 58 H 55B2NS2 (%) calcd: C, 81.78%; H, 6.51%; B, 2.54%; N, 1.64%; S, 7.53%; found: C, 81.80%; H, 6.55%; B, 2.58%; N, 1.66%; S, 7.41%.

[0110] Example 9

[0111] This example provides the synthesis of compound 64 (having the structure as shown in formula (I), wherein X is NR3, R3 is unsubstituted phenyl, Y1, Y2 are both NR4, R4 is unsubstituted phenyl, Ar1~Ar4 are all C4 alkyl), the synthetic route is shown below, the synthetic method refers to the synthesis of compound 13, the difference is that the raw material 4 is replaced by the raw material 11 in S1, and compound 64 (41.03 g, the yield is 43%) is synthesized.

[0112]

[0113] The characterization results of compound 64 are as follows: LC-MS: measured value: 970.5449 [M+H] + ; accurate mass: 970.5443. C 70 H 65 B2N3 (%) calcd: C, 86.68%; H, 6.76%; B, 2.23%; N, 4.33%; found: C, 86.69%; H, 6.71%; B, 2.20%; N, 4.40%.

[0114] Example 10

[0115] This example provides the synthesis of compound 80 (having the structure as shown in formula (I), wherein X is NR3, R3 is heteroaryl substituted by deuterium atom, Y1, Y2 are both NR4, R4 is unsubstituted phenyl, Ar1~Ar4 are all C4 alkyl), the synthetic route is shown below, the synthetic method refers to the synthesis of compound 13, the difference is that the raw material 4 is replaced by the raw material 12 in S1, and compound 80 (50.47 g, the yield is 48%) is synthesized.

[0116]

[0117] The characterization results of compound 80 are as follows: LC-MS: measured value: 1068.0640 [M+H] + ; accurate mass: 1068.0627. C 76 H 60D7B2N3O (%) Calculated: C, 85.55%; H, 6.99%; B, 2.03%; N, 3.94%; O, 1.50%; Found: C, 85.58%; H, 6.92%; B, 2.07%; N, 3.99%; O, 1.44%.

[0118] Example 11

[0119] This example provides the synthesis of compound 115 (having the structure as shown in formula (I), wherein X is adamantyl, Y1, Y2 are both NR4, R4 is unsubstituted phenyl, Ar1~Ar4 are all C4 alkyl), the synthetic route is shown below, the synthetic method refers to the synthesis of compound 13, the difference is that the raw material 4 is replaced by the raw material 13 in S1, and compound 115 (41.89g, the yield is 42%) is synthesized.

[0120]

[0121] The characterization results of compound 115 are as follows: LC-MS: measured value: 1014.6120 [M+H] + ; accurate mass: 1014.6116. C 74 H 74 B2N3 (%) Calculated: C, 87.74%; H, 7.36%; B, 2.13%; N, 2.77%; Found: C, 87.78%; H, 7.39%; B, 2.08%; N, 2.75%.

[0122] Example 12

[0123] This example provides the synthesis of compound 132 (having the structure as shown in formula (II), wherein X is NR3, R3 is unsubstituted phenyl; Y1, Y2 are both NR4, R4 is unsubstituted phenyl, Ar1~Ar4 are all C4 alkyl), the synthetic route is shown below, the synthetic method refers to the synthesis of compound 13, the difference is that the raw material 4 is replaced by the raw material 14 in S1, and compound 132 (8.47g, the yield is 48%) is synthesized.

[0124]

[0125] The characterization results of the obtained sample are as follows: LC-MS: measured value: 970.5450 [M+H] + ; accurate mass: 970.5443. C 70 H 65B2N3 (%) Calculated: C, 86.68%; H, 6.76%; B, 2.23%; N, 4.33%; Found: C, 86.60%; H, 6.71%; B, 2.28%; N, 4.42%.

[0126] Example 13

[0127] This example provides the synthesis of compound 136 (having a structure as shown in formula (II), wherein X is NR3, R3 is unsubstituted phenyl; Y1, Y2 are both NR4, R4 is dibenzofuranyl, Ar1~Ar4 are all C4 alkyl), the synthetic route is shown below, the synthetic method refers to the synthesis of compound 13, the difference is that the raw material 4 is replaced by the raw material 15 in S1, and compound 136 (9.27g, the yield is 44%) is synthesized.

[0128]

[0129] The characterization results of the obtained sample are: LC-MS: measured value: 1150.5650 [M+H] + ; accurate mass: 1150.5654. C 82 H 69 B2N3O (%) Calculated: C, 85.64%; H, 6.05%; B, 1.88%; N, 3.65%; O, 2.78%; Found: C, 85.68%; H, 6.06%; B, 1.83%; N, 3.69%; O, 2.74%.

[0130] Example 14

[0131] This example provides the synthesis of compound 138 (having a structure as shown in formula (II), wherein X is O; Y1, Y2 are both NR4, R4 is fluorenyl, Ar1~Ar4 are all C4 alkyl), the synthetic route is shown below, the synthetic method refers to the synthesis of compound 13, the difference is that the raw material 4 is replaced by the raw material 16 in S1, and compound 138 (9.42g, the yield is 45%) is synthesized.

[0132]

[0133] The characterization results of the obtained sample are: LC-MS: measured value: 1127.6218 [M+H] + ; accurate mass: 1127.6222. C 82 H 76 B2N2O (%) Calculated: C, 87.38%; H, 6.80%; B, 1.92%; N, 2.49%; O, 1.42%; Found: C, 87.32%; H, 6.88%; B, 1.96%; N, 2.44%; O, 1.40%.

[0134] Example 15

[0135] This example provides a synthesis of compound 140 (having a structure as shown in formula (II) wherein X is NR3; Y1, Y2 are both NR4, R4 is fluorenyl, Ar1~Ar4 are all C4 alkyl), the synthetic route is shown below, the synthetic method refers to the synthesis of compound 13, the difference is that in S1, the raw material 4 is replaced by raw material 17, and compound 140 (9.47g, yield 43%) is synthesized.

[0136]

[0137] The characterization results of the obtained sample are: LC-MS: measured value: 1202.6688 [M+H] + ; accurate mass: 1202.6695. C 88 H 81 B2N3 (%) calculated: C, 87.92%; H, 6.79%; B, 1.80%; N, 3.50%; found: C, 87.88%; H, 6.71%; B, 1.88%; N, 3.53%.

[0138] Example 16

[0139] This example provides a synthesis of compound 149 (having a structure as shown in formula (I) wherein X is CR1R2, R1, R2 are both methyl, Y1, Y2 are both NR4, R4 is phenyl substituted by methyl; Ar1~Ar4 are all phenyl), the synthetic route is shown below, the synthetic method refers to the synthesis of compound 13, the difference is that in S1, the raw material 1 is replaced by raw material 18, and the raw material 4 is replaced by raw material 19, and compound 149 (7.64g, yield 41%) is synthesized.

[0140]

[0141] The characterization results of the obtained sample are: LC-MS: measured value: 1085.5171 [M+H] + ; accurate mass: 1085.5177. C81H62B2N2 (%) calculated: C, 89.67%; H, 5.76%; B, 1.99%; N, 2.58%; found: C, 89.58%; H, 5.82%; B, 2.03%; N, 2.57%.

[0142] Example 17

[0143] This example provides a synthesis of compound 150 (having a structure as shown in Formula (I), wherein X is O, Y1, Y2are both O; Ar1~Ar4are all diphenylamine groups), the synthetic route is shown below, the synthetic method refers to the synthesis of compound 1, the difference is that in S1, raw material 1 is replaced by raw material 20, and raw material 2 is replaced by raw material 21, and compound 150 (9.21 g, yield 49%) is synthesized.

[0144]

[0145] The characterization results of the obtained sample are as follows: LC-MS: measured value: 1189.4469 [M+H] + ; accurate mass: 1189.4460. C84H54B2N4O3 (%) calculated value: C, 84.85%; H, 4.58%; B, 1.82%; N, 4.71%; O, 4.04%; found value: C, 84.86%; H, 4.67%; B, 1.76%; N, 4.77%; O, 3.94%.

[0146] Example 18

[0147] This example provides a synthesis of compound 151 (having a structure as shown in Formula (I), wherein X is S; Y1, Y2are both NR4, R4is a phenyl group substituted by a methyl group, and Ar1~Ar4are all carbazolyl groups), the synthetic route is shown below, the synthetic method refers to the synthesis of compound 13, the difference is that in S1, raw material 1 is replaced by raw material 22, and raw material 4 is replaced by raw material 23, and compound 151 (10.17 g, yield 46%) is synthesized.

[0148]

[0149] The characterization results of the obtained sample are as follows: LC-MS: measured value: 1431.5484 [M+H] + ; accurate mass: 1431.5491. C102H68B2N6S (%) calculated value: C, 85.59%; H, 4.79%; B, 1.51%; N, 5.87%; S, 2.24%; found value: C, 85.51%; H, 4.72%; B, 1.58%; N, 5.86%; S, 2.33%.

[0150] Example 19

[0151] This example simulates the physical and chemical properties of the compound.

[0152] The S1, T1 energy levels and HOMO, LUMO of compound 1, compound 3, compound 10, compound 13, compound 14, compound 19, compound 22, compound 25, compound 30, compound 38, compound 47, compound 57, compound 61, compound 62, compound 63, compound 64, compound 65, compound 68, compound 72, compound 76, compound 80, compound 85, compound 91, compound 93, compound 96, compound 100, compound 113, compound 115, compound 132, compound 136, compound 138, compound 140, compound 149, compound 150, compound 151 and existing light-emitting material BD01 are simulated and calculated, respectively. The HOMO and LUMO, S1 and T1 are data obtained by simulation calculation, the calculation method adopts B3LYP hybrid functional, the basis set is 6-31g (d, P), and the results are shown in Table 1.

[0153] Table 1: S1, T1 energy levels and HOMO, LUMO simulation results of compounds

[0154]

[0155]

[0156] As shown in Table 1, the HOMO energy level of the compound of the present application is between-4.816 and 5.669 eV, and the LUMO energy level is between-1.315 and-1.928, which has a wider band gap and better stability than BD01. The HOMO-LUMO energy level difference of the compound of the present application is 3.31-3.89, which is suitable as a blue light material. The single-triplet energy difference (△Est) of the compound of the present application is 0.017-0.219, which is smaller than that of BD01, and it is easier to occur from the single-triplet state to the single-triplet state. The gap crossing inversion is very important for realizing multiple resonance type thermal activated delayed fluorescence (MR-TADF).

[0157] Example 20

[0158] In this embodiment, some compounds are taken as examples, which are applied to organic electroluminescent devices as light-emitting materials of light-emitting layers. The structure of the organic electroluminescent device is specifically shown in Figure 1 which comprises a substrate 1, an anode layer 2, a hole injection layer 3, a hole transport layer 4, an electron blocking layer 5, a light-emitting layer 6, a hole blocking layer 7, an electron transport layer 8, an electron injection layer 9 and a cathode layer 10 which are sequentially stacked.

[0159] The substrate 1 is a 0.7 mm thick glass substrate, the anode layer 2 is made of indium tin oxide (ITO) with a high work function, the hole injection layer 3 is made of HT1 doped with HI-1, the mass ratio of HT1 to HI-1 is 97:3, and the thickness is 10 nm, the hole transport layer 4 is made of HT1, and the thickness is 60 nm, the electron blocking layer 5 is made of EB1, and the thickness is 15 nm, the light-emitting layer 6 is made of BH1 as a host material and BD01 or a compound prepared by the method of the application as a light-emitting material, the doping mass ratio is 5%, and the thickness is 30 nm, the hole blocking layer 7 is made of HB, and the thickness is 10 nm, the electron transport layer 8 is made of ET-1 doped with Liq, the doping concentration is 50 wt%, and the thickness is 30 nm, the electron injection layer 9 is made of Liq, and the thickness is 2 nm, and the cathode layer is made of Al, and the thickness is 100 nm.

[0160] The basic material structures used in the functional layers in the device are as follows:

[0161]

[0162] .

[0163] The specific preparation steps of the organic electroluminescent device are as follows:

[0164] 1) The ITO anode on the transparent glass or plastic substrate is cleaned, and ultrasonic cleaning is performed with deionized water, acetone and ethanol for 20 minutes respectively, and then plasma treatment is performed in an oxygen atmosphere for 5 minutes;

[0165] 2) The hole injection layer is deposited on the ITO anode layer by vacuum evaporation, the mass ratio of HT1 to HI-1 is 97:3, and the thickness is 10 nm;

[0166] 3) The hole transport material HT1 is deposited on the hole injection layer by vacuum evaporation, the thickness is 60 nm, and this layer serves as the hole transport layer;

[0167] 4) The electron blocking material EB1 is deposited on the hole transport layer HT1 by vacuum evaporation, the thickness is 15 nm, and this layer serves as the electron blocking layer;

[0168] 5) The light-emitting layer is co-deposited on the electron blocking layer by vacuum evaporation, BH1 is used as the host material, BD01 or a compound prepared by the method of the application is used as the light-emitting material, the doping mass ratio is 5%, and the thickness is 30 nm;

[0169] 6) The hole blocking material HB is deposited on the light-emitting layer by vacuum evaporation, the thickness is 10 nm, and this layer serves as the hole blocking layer;

[0170] 7) On the hole blocking layer, electron transport material ET-1:Liq was deposited by co-evaporation, the mass ratio was 1:1, and the thickness was 30 nm, which served as an electron transport layer;

[0171] 8) On the electron transport layer, electron injection material Liq was deposited by vacuum evaporation, and the thickness was 2 nm, which served as an electron injection layer;

[0172] 9) On the electron injection layer, cathode Al was deposited by vacuum evaporation, and the thickness was 100 nm, which served as a cathode conductive electrode.

[0173] The organic electroluminescent devices in each group were connected by a known driving circuit with the cathode and anode, and the photoelectric performance of the OLED device was tested by a standard method using a Keithley 2400 power supply combined with a PR670 luminometer, and the test results are shown in Table 2.

[0174] Table 2 Comparison of the composition of the light-emitting layer of each group of organic electroluminescent devices and the performance of the devices

[0175]

[0176] As can be seen from Table 2, the compound provided by the application has excellent performance when applied to an OLED device as a light-emitting material. Compared with the BD01 material described in Comparative Example 1, the device has improved luminous efficiency, a narrower half-peak width, and higher color purity when the compound of the application is selected as a light-emitting material. For example, when compound 30 is applied to an OLED device as a blue light host material, the external quantum efficiency (EQE) is improved by 39.2%, and the electro-optical conversion efficiency is more optimal. The compound prepared by the application has great application value in the application of OLED devices and has good industrialization prospects.

[0177] The five-membered heterocyclic double-boron polycyclic compound provided by the application has a sufficiently twisted molecular structure, high singlet and triplet energy, small singlet-triplet energy difference, and suitable HOMO and LUMO energy levels. The double-boron polycyclic compound ensures the rigidity of the compound while making the compound have a strong multiple resonance type thermally activated delayed fluorescence (MR-TADF) effect, which is applied to an OLED as a light-emitting material to narrow the emission spectrum and improve the efficiency, color purity, and other properties of the organic electroluminescent device, and can be widely applied to OLED light-emitting devices and display devices.

[0178] As described above, the basic principles, main features, and advantages of the application are better described. The above examples and descriptions only describe the preferred embodiments of the application, and the application is not limited by the above examples. Various changes and improvements to the technical solutions of the application made by those skilled in the art without departing from the spirit and scope of the application shall fall within the scope of protection of the application.

Claims

1. A compound, characterized in that, Having a structure as shown in formula (I) or formula (II), ； In formulas (I) and (II), X is selected from one of CR1R2, NR3, adamantyl, O, S, and Se; In formulas (I) and (II), Y1 and Y2 are selected from one of NR4, O, S, and Se; Ar1 to Ar4 in formula (I) and formula (II) are selected from hydrogen, deuterium, C1 to C5 alkyl, substituted or unsubstituted amino, substituted or unsubstituted C6 to C30 aryl, substituted or unsubstituted C6 to C30 heteroaryl. In CR1R2, R1 and R2 are methyl or phenyl; R3 in NR3 is a substituted or unsubstituted C6-C30 aryl group or a substituted or unsubstituted C6-C30 heteroaryl group; R4 in NR4 is a substituted or unsubstituted C6-C30 aryl group or a substituted or unsubstituted C6-C30 heteroaryl group; The C1-C5 alkyl groups are selected from one of methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, and neopentyl. The substituted or unsubstituted amino group is selected from one of the following structures. ； The substituted or unsubstituted aryl group of C6-C30 is selected from one of the following structures. ； The substituted or unsubstituted C6-C30 heteroaryl group is selected from one of the following structures. 。 2. The compound according to claim 1, characterized in that, Formula (I) has the structure shown in formulas A1 to A6. 。 3. The compound according to claim 1, characterized in that, Formula (II) has the structure shown in formulas B1 to B6. 。 4. The compound according to claim 1, characterized in that, It has the structure shown below. 。 5. The use of the compound according to any one of claims 1 to 4 in organic electroluminescent devices.

6. The use of the compound according to any one of claims 1 to 4 in an organic electroluminescent device.

7. An organic electroluminescent device, comprising an anode layer, a cathode layer, and an organic thin film layer located between the anode layer and the cathode layer, wherein the organic thin film layer comprises a hole injection layer, a hole transport layer, an electron blocking layer, a light-emitting layer, a hole blocking layer, an electron transport layer, and an electron injection layer, characterized in that, The light-emitting layer contains the compound according to any one of claims 1 to 4.

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