WO2022262310A1

WO2022262310A1 - Method for synthesizing btbf aromatic amine derivatives

Info

Publication number: WO2022262310A1
Application number: PCT/CN2022/078120
Authority: WO
Inventors: 陈少福; 黄科文; 鄢亮亮; 戴雷; 蔡丽菲
Original assignee: 广东阿格蕾雅光电材料有限公司
Priority date: 2021-06-17
Filing date: 2022-02-26
Publication date: 2022-12-22
Also published as: CN115490702A; TW202300493A

Abstract

The present invention provides a method for synthesizing BTBF aromatic amine derivatives, in which commercialized raw materials on the market are used, and after etherification, ring closure, bromination, and coupling reaction, target products, BTBF aromatic amine derivatives, are obtained. The method has the advantages of easily available raw materials, short route, high yield, simple purification process, and no need for column chromatography separation, is suitable for large-scale production, and is applicable to printing OLED devices because the obtained products have high purity and few impurities.

Description

The synthetic method of BTBF aromatic amine derivative

technical field

The invention relates to the technical field of OLED material preparation, in particular to a method for synthesizing BTBF aromatic amine derivatives.

Background technique

As an organic electroluminescent device of a new generation of display technology, OLED has a wide range of application prospects in display and lighting technology because of its self-luminescence, high contrast, wide color gamut, large viewing angle, and fast response speed.

OLED display technology mainly has two distinct manufacturing processes. One is the evaporation process, which uses small molecule OLED light-emitting materials to form films by vacuum evaporation. The current process is relatively mature, but it is time-consuming and laborious, and the material utilization rate is low. The cost is high; the other is the inkjet printing process, which uses a solvent to dissolve the OLED material into a uniform solution, and then sprays the solution directly on the surface of the substrate to form an RGB organic light-emitting layer. The material utilization rate is high, the operation is simple, and the cost is low. With its unique technical characteristics and production advantages, inkjet printing is gradually becoming the mainstream production process of OLED panels, which will change the production mode of the entire display industry.

At present, poly(3,4-ethylenedioxythiophene)-polystyrene sulfonate (PEDOT:PSS), as a hole-transport material for OLED, has excellent hole mobility and film-forming properties, and because of its good Solubility, can be configured as a uniform solution for printing OLED devices. However, because PEDOT:PSS is sensitive to water and easy to absorb moisture, it has a great impact on the efficiency and life of OLED devices, so it is still limited in practical applications. Benzofuran or benzothiophene compounds have relatively important applications in the field of OLEDs due to their high carrier mobility and high triplet energy level. Among them, benzothienobenzofuran (BTBF) arylamine derivatives

After structural modification, it not only has high mobility and triplet energy level, but also has good stability and solubility, and can be used as a hole transport material for inkjet printing OLED devices. The synthesis of BTBF arylamine derivatives is generally prepared by different ring closure methods to prepare BTBF, and then brominated to obtain BTBF-2Br

Continue to obtain BTBF arylamine derivatives through coupling reaction with diarylamine. Invention Patent 1 [CN110981889A] discloses the synthesis method of BTBF-like hole-transport materials and its application in vapor-deposited OLED devices. It does not describe the synthesis process of the key intermediate BTBF, and its synthesis of BTBF products requires column chromatography. Purification, no amplification feasibility; Invention Patent 2 [CN106883248A] discloses the synthesis of BTBF intermediates. Although this method has the advantage of short route (2 steps), the raw materials are expensive, and the selectivity of the Suzuki coupling reaction is poor. It is difficult to separate and purify, and the feasibility is low. Document 1 [Angew.Chem.Int.Ed.10.1002/anie.201801982] reported the synthesis of intermediate BTBF, but it needs to use boron trifluoride ether solution, the reaction is violent and dangerous, and it is not suitable for industrial scale-up. Document 2 [Chemistry Letters 2018, Vol.47, No.8, 1044-1047] also reported the synthesis of the intermediate BTBF, but the conversion rate of the product using toluene solvent in the first step was low, and it was identified that the reaction produced debromination of the raw material There are many by-products. The second step uses silver pivalate, which is expensive and difficult to obtain, and both steps require column chromatography, so the process needs to be further optimized, and it is not feasible to scale up. The synthesis method of BTBF arylamine derivatives reported in Document 3 [Organic Electronics 84 (2020) 105793] (as shown in the following route) requires 8 steps of reaction to obtain BTBF-DPA, which requires the use of DIBAL-H and liquid bromine, etc. It is a reagent with high risk, and the route is long, time-consuming, and the total yield is low. It is not suitable for industrial scale-up reactions, and the purity of the synthesized material is insufficient (99.27%, containing polyhalogenated impurities). It may be the synthesis of BTBF-2Br The use of liquid bromine is prone to polyhalogenation reactions and difficult to purify by column chromatography. The low purity of BTBF-2Br has a direct impact on the purity of the final product BTBF-DPA. The efficiency and lifetime of printed OLED devices made of poorly pure materials will be reduced. Therefore, based on the above factors, it is urgent to develop a new process to obtain high-purity BTBF aromatic amine derivatives, so as to avoid the influence of purity and impurities on OLED devices.

Contents of the invention

In order to solve the problems existing in the prior art, the present invention proposes a synthesis route and process suitable for the large-scale production of BTBF arylamine derivatives on the basis of the above-mentioned methods through a large number of patents and literature research, and by comparing the advantages and disadvantages of each route The method can be purified by distillation, crystallization, and sublimation, avoiding column chromatography purification, and has the advantages of short route, easy purification, short time consumption, and high product purity.

To achieve the above object, the present invention adopts the following technical solutions:

A synthetic method of BTBF arylamine derivatives shown in formula (I), wherein R ₁ , R ₂ are independently substituted or unsubstituted C6-C60 aryl, C6-C60 heteroaryl, C6-C60 A condensed ring aryl group or R ₁ and R ₂ are bonded to form a parallel ring, the substitution is substituted by a C1-C4 alkyl group, a C1-C4 alkoxy group or a phenyl group, and the heteroatoms in the heteroaryl group are S, At least one of N and O, its synthesis method comprises the following 2 steps:

(1) Synthesis of intermediate BTBF‐2Br

Using N,N-dimethylformamide as solvent and BTBF as raw material, N-bromosuccinimide was used for bromination reaction to obtain intermediate BTBF-2Br;

(2) The intermediate BTBF-2Br and the amine R ₁ R ₂ NH are reacted with Buchwald-Hartwig to obtain the target compound, wherein tris(dibenzylideneacetone) dipalladium and tri-tert-butylphosphine tetrafluoroborate are catalysts respectively And ligand, with sodium tert-butoxide or potassium tert-butoxide as reaction base, xylene as solvent,

The bromination reaction in the step (1) is slowly adding the N,N-dimethylformamide solution of N-bromosuccinimide to the N,N-dimethylformamide solution of BTBF, The reaction temperature is 0-10°C, and the reaction time is 8-20 hours.

The amount of reaction solvent added in the bromination reaction was 1g/18ml (BTBF-2Br/N, N-dimethylformamide), the amount of N-bromosuccinimide was 2.6 equivalents, and the reaction temperature was 5°C.

The step (1) also includes the purification of the reaction product BTBF-2Br, and the purification method is a recrystallization method; the crystallization solvent ratio is 1g solid and 2～8ml/5～15ml mixed solvent (tetrahydrofuran/n-hexane) is added for recrystallization. Crystallize twice, and then use 1g of solid to add 5ml-15ml of n-hexane to beat and purify; wherein, the crystallization temperature is 10-30°C, and the crystallization time is 2-10h. Among them, the preferred reaction solvent is 1g/18ml, the N-bromosuccinimide is 2.6 equivalents, and the reaction temperature is 5°C.

The Buchwald-Hartwig reaction condition of step (2) is that catalyst tris(dibenzylideneacetone) dipalladium is 1%～5% equivalent, and ligand tri-tert-butylphosphine tetrafluoroborate is 2%～10% equivalent, The reaction base sodium tert-butoxide is 2.1-3.0 equivalents, xylene is the reaction solvent, the reaction temperature is 130° C., and the reaction time is 4 hours.

After the step (2), it also includes post-reaction treatment and purification steps. The post-reaction treatment is to first add methanol equal in volume to the reaction solution, stir and precipitate the product, and filter to obtain the crude product; then dissolve it with toluene, and perform silica gel filtration to remove salt Carry out water washing again 3 times, described purification comprises recrystallization purification and/or sublimation purification step, described purification is to add equal volume methanol crystallization 1 time in the toluene solution after water washing, then repeat toluene dissolution and methanol crystallization 2 A product with more than 99.5% of the product is obtained once; the sublimation purification is to sublimate the crude product twice, wherein the sublimation temperature is 240-320° C., and the sublimation time is 3-10 hours, and a high-purity product with a purity of 99.9% or more is obtained.

Wherein the synthetic method of BTBF is:

Step 1-1: Use 3-bromobenzothiophene and phenol as raw materials, use copper acetylacetonate and iron triacetylacetonate as catalysts, triphenylphosphine oxide as ligand, potassium carbonate or sodium as base, and phenol as solvent Etherification reaction obtains 3‐phenoxybenzo [b] thiophene;

Step 1-2: Using palladium pivalate, palladium trifluoroacetate or palladium acetate as catalyst, sodium acetate, potassium acetate or silver acetate as alkaline condition, pivalic acid as solvent, 3‐phenoxybenzo[b] Thiophene ring closure reaction gives BTBF.

The etherification reaction conditions of the step 1-1 are as follows: phenol is used as a solvent, the raw material 3-bromobenzothiophene is 1 equivalent, the catalyst copper acetylacetonate and iron triacetylacetonate are 2% to 10% equivalent, and the ligand three The content of phenylphosphine oxide is 8%-16% equivalent, and the potassium carbonate is 2-6 equivalent; the reaction temperature is 120°C-165°C, and the reaction time is 6-24h.

Preferably, copper acetylacetonate is 3% equivalent, iron triacetylacetonate is 6% equivalent, triphenylphosphine oxide is 12% equivalent, potassium carbonate is 4 equivalent, the reaction temperature is 150° C., and the reaction time is 8 hours.

The ring closure reaction conditions of step 1-2 are as follows: 3-phenoxybenzo[b]thiophene is dissolved in a solvent, the reaction temperature is 120°C-145°C, and the reaction time is 8-12h. Preferably, the catalyst is palladium pivalate and the base is silver acetate.

The method also includes purification of the reaction product in step 1-1 and purification of the reaction product BTBF in step 1-2, the purification of the reaction product in step 1-1 is collected and purified by vacuum distillation to obtain a product with a purity of more than 99%; Wherein, the distillation temperature is 80° C. to 160° C., and the distillation pressure is 20° C. to 120 Pa.

The purification of the reaction product BTBF in step 1-2 adopts the recrystallization method; the crystallization solvent ratio is 1g solid, and 2-5ml/5-10ml mixed solvent (toluene/ethanol) is added to carry out recrystallization twice, and the crystallization temperature is 5-20°C. The crystallization time is 2~10h.

In the recrystallization method, the ratio of toluene/ethanol to 1g of solid is 3ml/6ml, the crystallization temperature is 5°C, and the crystallization time is 4h.

The BTBF arylamine derivative shown in formula (I) is any one of the following compounds:

The BTBF arylamine derivative synthesized by the invention can be prepared into a uniform solution with various solvents, and used as a hole transport layer material for inkjet printing OLED devices.

The preparation method proposed by the present invention overcomes the disadvantages of long synthetic route in the original preparation method, high risk of reagents used, and poor purification. The main advantages are: 1. The method for synthesizing intermediate BTBF in reference 2, the first step of the present invention The raw material phenol is used to replace toluene as a solvent, which greatly improves the yield and reduces the generation of by-products of raw material debromination, and can remove various impurities by distillation and section collection; the second step uses silver acetate instead of silver pivalate, which reduces the Material cost; two-step reaction without column chromatography purification. 2. In the method for synthesizing BTBF arylamine derivatives in reference 3, the steps of the route of the present invention are reduced to 4 steps, with high yield, short time consumption, and no use of high-risk reagents, and high process safety; 3. Synthesis of BTBF-2Br The use of N-bromosuccinimide (NBS) instead of liquid bromine reaction can reduce polyhalogenated impurities and is easy to purify; the whole process does not require column chromatography purification, and methods such as distillation, recrystallization, and sublimation are used to effectively improve The purity of BTBF arylamine derivatives is ensured, and the available high-purity products are beneficial to avoid the influence of impurities on the performance of OLED devices.

Description of drawings

Fig. 1 is the HNMR spectrogram of 3-phenoxybenzo [b] thiophene,

Fig. 2 is the HNMR spectrogram of BTBF,

Fig. 3 is the HNMR spectrogram of BTBF-2Br,

FIG. 4 is the HNMR spectrum of compound 1.

detailed description

The present invention will be further described in detail below in conjunction with the examples.

The synthesis of embodiment 1 intermediate BTBF:

1-1 Synthesis of intermediate 3-phenoxybenzo[b]thiophene:

In a 1L three-necked flask, add 3-bromobenzothiophene (55g, 258.1mmol, 1.0eq), phenol (364.35g, 3.87mol, 15.0eq), copper acetylacetonate (2.03g, 7.74mmol, 0.03eq) Iron triacetylacetonate (5.47g, 15.49mmol, 0.06eq), triphenylphosphine oxide (8.62g, 30.97mmol, 0.12eq), potassium carbonate (142.68g, 1.03mol, 4.0eq), vacuum, nitrogen replacement 3 times , heated to 150° C. for 8 hours, and a sample was taken for TLC spotting, which showed that the reaction of 3-bromobenzothiophene was basically complete, that is, the reaction was stopped. After cooling to room temperature, deionized water (250 ml) and ethyl acetate (250 ml) were added to the reaction solution, followed by washing with stirring and liquid separation. The upper organic phase was collected, and the aqueous phase was extracted once more with ethyl acetate (100 ml). The organic phase was collected, combined and concentrated twice. The concentrated crude product was subjected to vacuum distillation, and impurities and products were collected in sections. Use a mechanical pump to reduce the pressure of the reaction bottle to about 30Pa, and raise the temperature of the reaction device to 85°C. When the distillation temperature of the system reaches 73°C, start to distill out the phenol solvent and benzothiophene impurities, and collect the fraction ①; wait until no distillate flows out After that, the temperature was raised to 155°C. When the distillation temperature reached 143°C, the product was gradually distilled out, and a small amount of 3-5 g of impure product was collected in fraction ②; the product was collected by distillation again, which was fraction ③, and the white oily substance 3-benzene Oxybenzo[b]thiophene (45.64 g, 78.15% yield, 99.53% purity). Mass spectrum: 227.29 (M+H). ¹ H NMR (400MHz, CDCl ₃ ) δ7.90–7.76 (m, 2H), 7.47–7.34 (m, 4H), 7.23–7.12 (m, 3H), 6.72 (d , J=2.6Hz, 1H).

1-2 Synthesis of intermediate BTBF:

In a 1L three-necked flask, add 3-phenoxybenzo[b]thiophene (28g, 123.73mmol, 1.0eq), palladium pivalate (1.76g, 6.19mmol, 0.05eq), silver acetate (41.31g, 247.47mmol, 2.0eq), pivalic acid (189.5g, 1.86mol, 15.0eq), vacuum and nitrogen replacement 3 times, stirred and heated to 120°C under nitrogen protection, and reacted for 12h. Samples were taken for TLC spotting. The reaction of 3-phenoxybenzo[b]thiophene was complete, so the heating was stopped and the temperature was lowered to room temperature. 200 ml of deionized water and ethyl acetate (250 ml) were added to the reaction solution for stirring, washing with water, and liquid separation. The organic phase was collected and filtered with diatomaceous earth, and the filtrate was concentrated and dried to obtain a crude product. The crude product was heated to 90°C with toluene (83ml), stirred and dissolved completely, after cooling to room temperature, ethanol (166ml) was added, cooled to 5°C, stirred and crystallized for 4h, and an off-white solid was obtained by suction filtration. The toluene/ethanol crystallization was repeated once more (solvent ratio: product/toluene/ethanol=1g/3ml/6ml) to obtain white solid BTBF (24.07g, yield 86.73%, purity 99.65%). Mass spectrum: 225.28 (M+H). ¹ H NMR (400MHz, CDCl ₃ ) δ8.02 (d, J=7.6Hz, 1H), 7.89 (d, J=8.1Hz, 1H), 7.78–7.70 (m, 1H), 7.66(d, J=7.7Hz, 1H), 7.47(d, J=7.2Hz, 1H), 7.45–7.27(m, 3H).

The synthesis of embodiment 2 intermediate BTBF-2Br:

In a 500mL three-necked flask, add BTBF (22.35g, 99.65mmol, 1.0eq), N,N-dimethylformamide (268ml) respectively, vacuum and nitrogen replacement 3 times, and cool the reaction solution to 5 At the same time, N-bromosuccinimide (46.12g, 259.1mmol, 2.6eq) was dissolved in N,N-dimethylformamide (138ml), and slowly added dropwise to the original reaction solution. 0.5h. After the dropwise addition, return to room temperature and react for 6h. Samples were taken for TLC spotting, and BTBF had completely reacted. The reaction solution was added into a 1 L single-necked bottle filled with deionized water (487 ml), stirred for 1 h, a solid was precipitated, and the solid was collected by filtration. Add the solid to tetrahydrofuran (152ml), heat to 60°C, stir to dissolve completely, add n-hexane (456ml) after cooling to room temperature, cool down to 10°C, stir and crystallize for 3h, and filter to obtain the solid. The tetrahydrofuran/n-hexane crystallization was repeated once more (solvent ratio: product/tetrahydrofuran/n-hexane=1g/4ml/12ml), and a solid was obtained by filtration. The solid was added into n-hexane (300ml) for stirring and beating for 2h, and filtered to obtain a white solid BTBF-2Br (27.89g, yield 73.25%, purity 99.12%). Mass spectrum: 383.07 (M+H). ¹ H NMR (400MHz, CDCl ₃ ) δ8.01 (s, 1H), 7.82 (dd, J=13.3, 4.9Hz, 2H), 7.61–7.55 (m, 2H), 7.49(s,1H).

The synthesis of embodiment 3 compound 1:

In a 500mL three-necked flask, add BTBF-2Br (10.3g, 26.96mmol, 1.0eq), diphenylamine (10.95g, 64.70mmol, 2.4eq), sodium tert-butoxide (7.77g, 80.88mmol, 3.0eq), Tris(dibenzylideneacetone)dipalladium (0.74g, 808.7umol, 0.03eq) and tri-tert-butylphosphine tetrafluoroborate (0.46g, 1.62mmol, 0.06eq), anhydrous xylene (150mL), Vacuum and nitrogen replacement 3 times, heated to 130°C under nitrogen protection, and reacted for 4 hours. Sampling for TLC plate, BTBF-2Br has been completely reacted. After cooling down to room temperature, methanol (150 ml) was slowly added to the reaction solution, stirred for 1 h, and a solid precipitated out, which was collected by filtration. Add the solid to toluene (225ml), heat to 102°C, stir to dissolve completely, and after cooling to room temperature, pour it into a funnel equipped with silica gel (40g, 200-300 mesh), collect the filtrate by filtration, and add the filtrate to the Wash with deionized water 3 times (75ml each time), collect the toluene phase by liquid separation, then slowly add methanol (225ml) dropwise, stir and crystallize for 3h, and filter to obtain the crude product. Repeat the crystallization and purification with toluene and methanol twice (solvent ratio: product/toluene/methanol=1g/15ml/15ml) to obtain white solid compound 1 (12.45g, yield 82.64%, purity 99.89%), and 12.45 grams of crude product , sublimated at 260°C for 7 hours at a vacuum of 3.2*10 ^-4 Pa to obtain sublimated pure compound 1 (10.2 g, yield 81.92%, purity 99.98%). Mass spectrum: 559.69 (M+H).) ¹ H NMR (400MHz, CDCl ₃ ) δ7.75 (d, J=8.6Hz, 1H), 7.50 (d, J=8.8Hz, 2H), 7.36–7.19 (m ,10H),7.18–6.94(m,13H).

The present invention compares with the synthetic process result of document 2, document 3:

The synthesis of embodiment 4 compound 3:

In a 500mL three-necked flask, BTBF-2Br (8.65g, 22.4mmol, 1.0eq), bis(4-biphenyl)amine (17.28g, 53.77mmol, 2.4eq), sodium tert-butoxide (6.46g, 67.21mmol, 3.0eq), tris(dibenzylideneacetone)dipalladium (0.61g, 672.1umol, 0.03eq) and tri-tert-butylphosphine tetrafluoroborate (0.39g, 1.34mmol, 0.06eq), no Water xylene (128mL), vacuum, nitrogen replacement 3 times, heated to 130°C under nitrogen protection, reacted for 4h. Sampling for TLC plate, BTBF-2Br has been completely reacted. After cooling down to room temperature, methanol (128 ml) was slowly added to the reaction solution, stirred for 1 h, and a solid precipitated out, which was collected by filtration. Add the solid to toluene (290ml), heat to 105°C, stir to dissolve completely, and after cooling to room temperature, pour it into a funnel equipped with silica gel (40g, 200-300 mesh), collect the filtrate by filtration, and add the filtrate to the Wash with deionized water three times (90ml each time), collect the toluene phase by liquid separation, then slowly add methanol (290ml) dropwise, stir and crystallize for 3h, and filter to obtain the crude product. Repeated crystallization and purification with toluene and methanol twice (solvent ratio: product/toluene/methanol=1g/15ml/15ml) to obtain white solid compound 3 (15.34g, yield 79.34%, purity 99.86%), 11.83 grams of crude product , sublimated at 293°C for 8.5 hours at a vacuum of 2.6*10 ^-4 Pa to obtain sublimated pure compound 3 (11.63 g, yield 75.81%, purity 99.98%). Mass spectrum: 864.0 (M+H). ¹ H NMR (400MHz, CDCl ₃ ) δ7.86 (d, J = 8.4Hz, 1H), 7.74 (d, J = 5.0Hz, 9H), 7.61 (d, J = 8.7Hz, 1H), 7.52(m, 17H), 7.39(d, J=20.0Hz, 12H), 7.21(dd, 1H), 7.03(dd, 1H).

The synthesis of embodiment 5 compound 9:

In a 500mL three-necked flask, add BTBF-2Br (7.36g, 19.26mmol, 1.0eq), N-[1,1'-biphenyl]-2-yl-9,9-dimethyl-9H-fluorene- 2-amine (16.71g, 46.23mmol, 2.4eq), sodium tert-butoxide (5.55g, 57.79mmol, 3.0eq), tris(dibenzylideneacetone)dipalladium (0.52g, 577.9umol, 0.03eq) and Tri-tert-butylphosphine tetrafluoroborate (0.33g, 1.16mmol, 0.06eq), anhydrous xylene (110mL), vacuum and nitrogen replacement 3 times, heated to 130°C under nitrogen protection, and reacted for 3.5h. Sampling for TLC plate, BTBF-2Br has been completely reacted. After cooling down to room temperature, methanol (110 ml) was slowly added to the reaction solution, stirred for 1 h, and a solid precipitated out, which was collected by filtration. Add the solid to toluene (270ml), heat to 95°C, stir to dissolve completely, and after cooling to room temperature, pour it into a funnel equipped with silica gel (40g, 200-300 mesh), collect the filtrate by filtration, and add the filtrate to the Wash with deionized water three times (90ml each time), collect the toluene phase by liquid separation, slowly add methanol (270ml) dropwise, stir and crystallize for 3h, and filter to obtain the crude product. Repeat crystallization and purification with toluene and methanol twice (solvent ratio: product/toluene/methanol=1g/15ml/15ml) to obtain white solid compound 9 (13.88g, yield 76.38%, purity 99.91%). 13.88 g of the crude product were sublimed at 315°C for 8 h under a vacuum of 2.9*10 ^-4 Pa to obtain sublimated pure compound 9 (10.63 g, yield 76.58%, purity 99.97%). Mass spectrum: 944.2 (M+H). ¹ H NMR (400MHz, CDCl ₃ ) δ8.10 (d, J = 9.3Hz, 2H), 8.03 (d, J = 8.6Hz, 1H), 7.88 (m, 4H) ,7.74(d,J＝8.4Hz,1H),7.65–7.49(m,5H),7.40(m,13H),7.26(m,4H),7.18–6.99(m,8H),1.69(s,12H ).

Application example:

Fabrication of Organic Electroluminescent Devices

A 50mm*50mm*1.0mm glass substrate with an ITO (100nm) transparent electrode was ultrasonically cleaned in ethanol for 10 minutes, dried at 150°C and then treated with N ₂ Plasma for 30 minutes. A hole injection layer (HIL, 10 nm) using PEDOT-PSS was inkjet printed onto the substrate and dried in vacuum. The HIL was then annealed at 185 °C for 30 min in air. The high-purity material synthesized in Example 3-5 and comparative example compound 1 (purity 99.27%), comparative material PVK are prepared into solution AF (solvent is methyl benzoate, concentration is 23mg/ml), inkjet printing on HIL Above (20nm), as a hole transport layer (HTL, 20nm), dried in vacuum, and then annealed at 210° C. for 30 minutes in a nitrogen atmosphere. The green light-emitting layer (G-EML, 15 nm) was inkjet printed, dried in vacuum, and then annealed at 160° C. for 10 minutes in a nitrogen atmosphere. The ink used for the green light-emitting layer contains two host materials (ie Host 1 and Host 2) and a green dopant material (GD), and the solvent is cyclohexylbenzene. The ratio of host material and dopant material is 47%:47%:6%. The device is then transferred to a vacuum deposition chamber, where the ETL film (25nm) and the LiQ film (1nm) are evaporated sequentially on the light-emitting layer, and finally a layer of metal Al (100nm) is evaporated as an electrode.

Evaluation:

The above-mentioned devices were tested for device performance. In each embodiment and comparative example, a constant current power supply (Keithley2400) was used, a fixed current density was used to flow through the light-emitting element, and a spectroradiometer (CS 2000) was used to test the luminescent spectrum. Simultaneously measure the voltage value and the time when the test brightness is 90% of the initial brightness (LT90). The result is as follows:

From the comparison of the data in the above table, it can be seen that the high-purity material compound 1, compound 3, and compound 9 obtained by the synthesis process of the present invention in devices 1-3 are used as hole transport layer ink material solutions A-C to prepare OLED devices. Voltage, efficiency , life are all better than comparative example 1 (solution D, compound 1 purity 99.27%), the purity of material, organic impurity, inorganic impurity that illustrate material have greater influence on the performance of device, and the high-purity material that adopts the synthesis of technology of the present invention embodies superior device performance. At the same time, compared with the solution E prepared from the traditional material PVK in Comparative Example 2 as the ink material of the hole transport layer, the devices 1-3 also showed more superior performance.

According to the synthesis process results of Examples 3-5, the present invention has the advantages of short process route, easy access to raw materials, high total yield, and high product purity. At the same time, each step can be purified by distillation, recrystallization, sublimation, etc. Scale up production feasibility. The performance of printed OLED devices according to the application examples shows that the high-purity BTBF aromatic amine derivatives obtained by the process of the present invention, as a hole transport ink material, can effectively improve the luminous efficiency and life of printed OLED devices, and have the potential to be used in inkjet printing The possibility of mass production of OLED technology.

Claims

A synthetic method of BTBF arylamine derivatives shown in formula (I), wherein R 1 , R 2 are independently substituted or unsubstituted C6-C60 aryl, C6-C60 heteroaryl, C6-C60 A condensed ring aryl group or R 1 and R 2 are bonded to form a parallel ring, the substitution is substituted by a C1-C4 alkyl group, a C1-C4 alkoxy group or a phenyl group, and the heteroatoms in the heteroaryl group are S, At least one of N and O, its synthesis method comprises the following 2 steps:

(1) Synthesis of intermediate BTBF‐2Br

Using N,N-dimethylformamide as solvent and BTBF as raw material, N-bromosuccinimide was used for bromination reaction to obtain intermediate BTBF-2Br;

(2) The intermediate BTBF-2Br and the amine R 1 R 2 NH are reacted with Buchwald-Hartwig to obtain the target compound, wherein tris(dibenzylideneacetone) dipalladium and tri-tert-butylphosphine tetrafluoroborate are catalysts respectively And ligand, with sodium tert-butoxide or potassium tert-butoxide as reaction base, xylene as solvent,
The synthetic method according to claim 1, the bromination reaction in the described step (1) is slowly adding the N,N-dimethylformamide solution of N-bromosuccinimide to the N of BTBF, In N-dimethylformamide solution, the reaction temperature is 0-10°C, and the reaction time is 8-20 hours.
The synthetic method according to claim 2, in the bromination reaction, the reaction solvent addition BTBF-2Br/N, N-dimethylformamide is 1g/18ml, and N-bromosuccinimide is 2.6 equivalents , and the reaction temperature was 5°C.
According to the synthetic method described in claim 2, said step (1) also includes the purification of the reaction product BTBF-2Br, said purification method is a recrystallization method; adopting a crystallization solvent ratio is that 1g solids add 2～8ml/5～ 15ml mixed solvent tetrahydrofuran/n-hexane was recrystallized twice, and then 1g solid was added to 5ml-15ml n-hexane for beating and purification; wherein, the crystallization temperature was 10-30°C, and the crystallization time was 2-10h.
The synthetic method according to claim 1, the Buchwald-Hartwig reaction condition of step (2) is that catalyst tris(dibenzylideneacetone) dipalladium is 1%～5% equivalent, and ligand tri-tert-butylphosphinetetrafluoroboron The acid salt is 2%-10% equivalent, the reaction base sodium tert-butoxide is 2.1-3.0 equivalent, xylene is the reaction solvent, the reaction temperature is 130° C., and the reaction time is 4 hours.
The synthetic method according to claim 5, said step (2) also includes post-reaction treatment and purification steps, said post-reaction treatment is first adding methanol equal in volume to the reaction solution, stirring to separate out the product, and filtering to obtain the crude product; Then use toluene to dissolve, carry out silica gel filtration to desalinate; then wash with water 3 times, the purification includes recrystallization purification and/or sublimation purification steps, the purification is to add an equal volume of methanol to the toluene solution after washing for crystallization once , repeat toluene dissolution and methanol crystallization twice to obtain more than 99.5% of the product; the sublimation purification is to carry out two sublimation of the crude product, wherein the sublimation temperature is 240-320 ° C, the sublimation time is 3-10h, and the purity of more than 99.9% is obtained of high-purity products.
synthetic method according to claim 1, wherein the synthetic method of BTBF is:

Step 1-1: Use 3-bromobenzothiophene and phenol as raw materials, use copper acetylacetonate and iron triacetylacetonate as catalysts, triphenylphosphine oxide as ligand, potassium carbonate or sodium as base, and phenol as solvent Etherification reaction obtains 3‐phenoxybenzo [b] thiophene;

Step 1-2: Using palladium pivalate, palladium trifluoroacetate or palladium acetate as catalyst, sodium acetate, potassium acetate or silver acetate as alkaline condition, pivalic acid as solvent, 3‐phenoxybenzo[b] Thiophene ring closure reaction gives BTBF.
according to the synthetic method described in claim 7, the etherification reaction condition of described step 1-1 is, adopts phenol to do solvent, raw material 3-bromobenzothiophene is 1 equivalent, catalyst copper acetylacetonate and iron triacetylacetonate are 2% to 10% equivalent, the ligand triphenylphosphine oxide is 8% to 16% equivalent, and potassium carbonate is 2 to 6 equivalent; the reaction temperature is 120°C to 165°C, and the reaction time is 6 to 24h; the step 1- 2. The ring closure reaction conditions are as follows: 3-phenoxybenzo[b]thiophene is dissolved in a solvent, the reaction temperature is 120°C-145°C, and the reaction time is 8-12h.
The synthetic method according to claim 8, described method also comprises step 1-1 reaction product purification and the purification of step 1-2 reaction product BTBF, described step 1-1 reaction product purification adopts vacuum distillation to carry out segmentation Collect and purify to obtain a product with a purity of more than 99%. Among them, the distillation temperature is 80°C to 160°C, and the distillation pressure is 20°C to 120Pa;

The purification of the reaction product BTBF in step 1-2 adopts the recrystallization method; the crystallization solvent ratio is 1g solid, and 2-5ml/5-10ml mixed solvent toluene/ethanol is used for recrystallization twice, and the crystallization temperature is 5-20°C. The time is 2-10 hours.
According to the arbitrary described synthetic method of claim 1-9, the BTBF arylamine derivative shown in formula (I) is any one in the following compounds: