CN102229623B - Spirofluorene xanthene phosphine oxide electro-phosphorescent main materials and synthesis and application methods thereof - Google Patents

Abstract

Spirofluorene xanthene phosphorus oxide-based electrophosphorescent host materials and their synthesis and application methods belong to the field of optoelectronic materials technology, specifically four spirofluorene xanthene organic phosphorus oxide materials, and the application of such materials in organic electroluminescence Materials, organic solar cells, organic field effect tubes, dye lasers, organic nonlinear optical materials and fluorescent probes and other organic electronics fields. The series of materials are obtained by introducing diphenylphosphoryl groups into the 2-position, 2,7-position, 2'-position and 2'-7'-position of spirofluorene xanthene respectively. The series of compounds have good charge transport performance, thermal stability and high triplet energy level (E _T =-2.86eV), and can be used as host materials in phosphorescent devices. It is applied in organic electroluminescent phosphorescent devices, the maximum external quantum efficiency of blue phosphorescent devices is 10.78%, and the maximum brightness is 8582cd/m ² . In green phosphorescent devices, the maximum external quantum efficiency is 19.1%, and the maximum brightness is 16943 cd/m ² .

Description

Spirofluorene xanthene phosphorus oxide electrophosphorescent host material and its synthesis and application method

technical field

The invention belongs to the field of organic electroluminescent materials. It specifically relates to the synthesis of a class of spirofluorene xanthene diphenylphosphine oxide series compounds, and the application of the material in the field of organic electroluminescence.

technical background

Since the Tang research group of Kodak Corporation of the United States published thin-film organic electroluminescent devices (Organic Light-emitting Diodes, OLED) made of organic fluorescent materials in 1987, organic flat panel display has become another generation of market-oriented display after liquid crystal display. product. The advantages of OLED are self-illumination, wide viewing angle (up to 170°), fast response time (on the order of 1 μs), high luminous efficiency, low operating voltage (3-10V), and thin panel thickness (less than 2mm). Therefore, the development of new organic optoelectronic information materials with practical market potential has attracted the attention and investment of many scientists from different disciplines in universities at home and abroad, as well as research institutions and companies.

According to the principle of luminescence, organic electroluminescence can be divided into singlet fluorescence and triplet phosphorescence. For phosphorescence, it can increase the internal quantum efficiency of fluorescent dopants commonly used in devices from 25% to 100%. However, phosphorescent materials are usually complexes composed of heavy metal atoms, which use the strong spin-orbit coupling effect of heavy atoms to cause the transition from the lowest triplet state to the singlet state, so that the excitons of the singlet excited state and the triplet excited state have the same energy. Can be used for luminescence. However, due to the concentration quenching and triplet-triplet annihilation effects of phosphorescent materials, the phosphorescent quantum efficiency is reduced. Therefore, in phosphorescent devices, host materials are usually doped in phosphorescent guest materials.

Most of the currently reported host materials are limited to compounds containing carbazole and silicon. The disadvantages of these host materials are low triplet energy levels, low thermal and morphological stability. For the currently commonly used host material 4,4'-bis(N-carbazole)-2,2'-biphenyl (CBP), due to the low triplet state energy ( _ET = 2.65eV), it is easy to generate from the guest phosphorescent material The energy returned to the host material reduces the efficiency of the device, so it is not easy to be used as the host material of the blue phosphorescent material. The researchers then chemically modified CBP to increase its triplet energy level to 2.9-3.0eV. The triplet energy level of silicon-containing organic compounds ( _ET > 3.5eV), however, these materials have poor thermal stability and morphological stability, and their _Tg temperature is low (26-101°C). Therefore, due to the existence of these disadvantages, the application of these materials as host materials in devices is limited to some extent. It is worth mentioning that most of these reported host materials are hole-transporting materials, and relatively few host materials with electron-transporting properties have been reported. The electron transport properties of materials are of great significance to the performance of devices. Phosphorus-oxygen compounds have good electron transport properties and high triplet energy levels, and are a class of excellent host materials.

As we all know, spirofluorene xanthene has good luminescence quantum efficiency and charge transport performance, good thermal stability and morphological stability. The triplet energy level of the whole compound can be improved by introducing diphenylphosphine group into spirofluorene xanthene. The obtained spirofluorene xanthene phosphorus oxygen compound has higher triplet energy level, better charge transport performance, higher thermal stability and shape stability, and can be used as a host material in phosphorescent devices. Moreover, the one-pot preparation of spirofluorenexanthene is a very mature reaction in our laboratory, with high yield and simple method, which lays the foundation for the synthesis of spirofluorenexanthene phosphorus-oxygen host materials.

Contents of the invention

Technical problem: The purpose of the present invention is to propose a spirofluorene xanthene phosphorus oxide electrophosphorescent host material and its synthesis and application method.

Technical solution: The spirofluorenexanthene phosphorus oxygen-based electrophosphorescent host material of the present invention is that diphenylphosphoryl groups are introduced into different positions of spirofluorenexanthene, and its structural characteristics are as follows:

Wherein, R ₁ , R ₂ , R ₃ and R ₄ are diphenylphosphine groups or H atoms.

R ₁ is a diphenylphosphinyl group, and R ₂ , R ₃ and R ₄ are H atoms, and its structure is as follows:

R ₁ and R ₂ are diphenylphosphinyl groups, while R ₃ and R ₄ are H atoms, and its structure is as follows:

R ₃ is a diphenylphosphinyl group, and R ₁ , R ₂ and R ₄ are H atoms, and its structure is as follows:

R ₃ and R ₄ are diphenylphosphine groups, R ₁ and R ₂ are H atoms, and its structure is as follows:

The specific preparation steps of the preparation method of the spirofluorenexanthene phosphorus oxide electrophosphorescent host material of the present invention are as follows:

The specific preparation steps of the preparation method of compound I are as follows:

a. At 150°C, 10 times the equivalent of phenol and 2-bromo-9-fluorenone 1 were reacted under the catalysis of methanesulfonic acid for 2 hours, and then the product was separated by silica gel column chromatography to obtain product 2;

b. Dissolving 2 in tetrahydrofuran, and performing halide-lithium exchange reaction with n-butyllithium at -78°C for 1 hour to form lithium salt 3;

c. At -78°C, add diphenylphosphorus chloride into the above reaction system, react at low temperature for 1 hour, and react at room temperature for 10 hours. Then water was added to quench the reaction, and the reactant was extracted with dichloromethane, and finally concentrated to obtain product 4 in the crude product;

d. Dissolve the concentrated product with dichloromethane, add 2 times the equivalent of hydrogen peroxide for oxidation, and react for 10 hours. The product is spin-dried with a rotary evaporator and then separated by column chromatography to obtain product 5.

The specific preparation steps of the preparation method of compound II are as follows:

a. At 150°C, 10 times the equivalent of phenol and 2,7-dibromo-9-fluorenone 1 were reacted under the catalysis of methanesulfonic acid for 2 hours, and then the product was separated by silica gel column chromatography to obtain product 2;

b. Dissolving 2 in tetrahydrofuran, and performing halide-lithium exchange reaction with n-butyllithium at -78°C for 1 hour to form lithium salt 3;

c. At -78°C, add diphenylphosphorus chloride into the above reaction system, react at low temperature for 1 hour, and react at room temperature for 10 hours. Then add water to quench the reaction, and use dichloromethane to extract the reactant, and finally concentrate to obtain the crude product containing product 4 and product 5

d. Dissolve the concentrated product with dichloromethane, add 2 times the equivalent of hydrogen peroxide to oxidize, and react for 10 hours. The product is spin-dried with a rotary evaporator and then separated by column chromatography to obtain product 6 and product 7. The mass ratio is 10:1.

The specific preparation steps of compound III and compound IV are as follows:

a. At 150°C, 10 times the equivalent of phenol and 9-fluorenone 1 were reacted under the catalysis of methanesulfonic acid for 2 hours, and then the product was separated by silica gel column chromatography to obtain product 2;

b. Dissolving 2 in tetrahydrofuran, and performing halide-lithium exchange reaction with n-butyllithium at -78°C for 1 hour to form lithium salt 3;

c. At -78°C, add diphenylphosphorus chloride into the above reaction system, react at low temperature for 1 hour, and react at room temperature for 10 hours. Then water was added to quench the reaction, and the reactant was extracted with dichloromethane, and finally concentrated to obtain product 4 and product 5 in the crude product;

d. Dissolve the concentrated product with dichloromethane, add 2 times the equivalent of hydrogen peroxide to oxidize, and react for 10 hours. The product is spin-dried with a rotary evaporator and then separated by column chromatography to obtain product 6 and product 7. The mass ratio is 1.5:1.

The host material is used in organic electrophosphorescent light-emitting devices, and the structure of the device is: transparent anode/hole injection layer/hole transport layer/electron blocking layer/host material and guest material/hole blocking layer/electron transport layer/ Electron injection layer/cathode, the light emitting layer is composed of host material and metal ligand phosphorescent material doped, the host material of the light emitting layer is the compound described in Claim 1.

The application method of the spirofluorene xanthene phosphorus oxygen-based electrophosphorescent host material of the present invention lies in that the structure of the device in the organic electroluminescent blue phosphorescent device is: transparent anode/hole injection layer/hole transport layer/electron Blocking layer/host material and guest material/hole blocking layer/electron transport layer/electron injection layer/cathode, the light-emitting layer is composed of a host material and a dopant material, the host material of the light-emitting layer is the compound described in claim 1, and the guest material It is a metal complex blue phosphorescent material.

The structure of the device in the organic electro-green phosphorescent device is: transparent anode/hole injection layer/hole transport layer/electron blocking layer/host material and guest material/hole blocking layer/electron transport layer/electron injection layer/cathode , the light-emitting layer is composed of a host material and a metal ligand phosphorescent material doped, the host material of the light-emitting layer is the compound described in claim 1, and the guest material is a metal complex green phosphorescent material.

In an organic electroluminescent red phosphorescent device, the structure of the device is: transparent anode/hole injection layer/hole transport layer/electron blocking layer/host material and guest material/hole blocking layer/electron transport layer/electron injection layer/ The cathode and the light-emitting layer are composed of a host material and a metal ligand phosphorescent material doped, and the host material of the light-emitting layer is the compound described in claim 1, which is a metal complex red phosphorescent material.

Beneficial effects: the synthesis of this series of compounds is based on the one-pot preparation of spirofluorene xanthene, the synthesis method is simple and easy, the cost of raw materials is low, and it is suitable for mass production. From the raw material to the target product, the whole synthetic route is only three steps, so it provides sufficient and necessary conditions for the large-scale synthesis of the phosphorus-oxygen host material of spirofluorene xanthene. It laid the foundation for the industrial production of the material. In terms of material performance, the phosphorus-oxygen host material of spirofluorene xanthene has high triplet energy, good charge transport ability, and high thermal stability, which provides conditions for the preparation of organic electrophosphorescent devices.

Description of drawings

Figure 1 is the nuclear magnetic H ¹ NMR of 2-phenylphosphoxy-spirofluorene xanthene

Figure 2 is the nuclear magnetic H ¹ NMR of 2,7-bisphenylphosphine-spirofluorene xanthene

Figure 3 is the nuclear magnetic H ¹ NMR of 2'-phenylphosphonoxy-spirofluorene xanthene

Figure 4 is the nuclear magnetic H ¹ NMR of 2', 7'-bisphenylphosphinoxy-spirofluorene xanthene

Figure 5 is the ultraviolet absorption spectrum and fluorescence emission spectrum of 2-phenylphosphonoxy-spirofluorene xanthene

Figure 6 is the ultraviolet absorption spectrum and fluorescence emission spectrum of 2,7-bisphenylphosphoroxy-spirofluorene xanthene

Fig. 7 is the ultraviolet absorption spectrum and the fluorescence emission spectrum of 2'-phenylphosphoroxy-spirofluorene xanthene

Figure 8 is the ultraviolet absorption spectrum and fluorescence emission spectrum of 2'7'-bisphenylphosphine oxygen-spirofluorene xanthene

Figure 9 is a device structure diagram of a phosphorescent device prepared with spirofluorene xanthene phosphorus oxide as the host material

Figure 10 is the electroluminescence spectrum of the green phosphorescent device of spirofluorene xanthene phosphorus oxide

Figure 11 is the voltage-brightness curve of the green phosphorescent device of spirofluorene xanthene phosphorus oxide

Figure 12 is the brightness-external quantum efficiency curve of the green phosphorescent device of spirofluorene xanthene phosphorus oxide

Figure 13 is the electroluminescence spectrum of the blue phosphorescence device of spirofluorene xanthene phosphorus oxide

Figure 14 is the voltage-brightness curve of the blue phosphorescent device of spirofluorene xanthene phosphorus oxide

Figure 15 is the brightness-external quantum efficiency curve of the blue phosphorescent device of spirofluorene xanthene phosphorus oxide

Detailed ways:

The spirofluorene xanthene phosphorus oxide host material of the present invention has the following general structural formula:

R ₁ , R ₂ , R ₃ and R ₄ are diphenylphosphinyl groups or H atoms

Above-mentioned compound of the present invention, be following four kinds:

R ₁ is a diphenylphosphine group, R ₂ , R ₃ and R ₄ are H atoms, and its structure is as follows:

R ₁ and R ₂ are diphenylphosphine groups, R ₃ and R ₄ are H atoms, and its structure is as follows:

R ₃ is a diphenylphosphine group, R ₁ , R ₂ and R ₄ are H atoms, and its structure is as follows:

R ₃ and R ₄ are diphenylphosphine groups, R ₁ and R ₂ are H atoms, and its structure is as follows:

(1) Synthesis of 2,7-dibromo-spirofluorene xanthene or 2'7'-dibromo-spirofluorene xanthene monomer

Utilize the preparation method of one-pot spirocycle (such as literature: Org.Lett.2006 (8), 2787-2790), under the protection of inert gas, 10 times of equivalents of phenol (or p-bromophenol) and 1 times of equivalents of 2 , 7-dibromo-9-fluorenone (or 9-fluorenone) at 150 ° C, and then add 4 times the equivalent of methanesulfonic acid to catalyze the reaction for 12 hours. The monomer product was obtained by silica gel column chromatography.

(2) Synthesis of organophosphorus compounds of spirofluorene xanthene

Under the protection of an inert gas, dissolve 1 times the equivalent of the reactant (bromine-containing spirofluorene xanthene) in tetrahydrofuran solution (THF), and slowly add 1.5 times the equivalent of n-butyl at low temperature (-78°C) Lithium, using n-butyllithium and the reactant (bromine-containing spirofluorene xanthene) for lithium halide exchange, so that the spirofluorene xanthene forms a lithium salt, and then reacts at low temperature (-78 ° C) for 3 hours, and finally At low temperature (-78°C), diphenyl phosphorus chloride is added to react with lithium salt of spirofluorene xanthene to generate spirofluorene xanthene phenyl phosphorus product. The crude product was extracted with dichloromethane and dried to proceed directly to the next reaction.

(3) Synthesis of the phosphorus-oxygen host material of spirofluorene xanthene

Utilize (two) to obtain the crude product of the organophosphorus compound containing spirofluorene xanthene as raw material, under 0 ℃, add hydrogen peroxide (30%) (5 times equivalent) to carry out oxidation reaction, make trivalent phosphorus oxidize into 5 valent, A crude product containing diphenylphosphine was obtained. The crude product was separated by silica gel column chromatography to obtain pure product.

Application method, the host material is used in an organic electrophosphorescent light-emitting device, and the structure of the device is: transparent anode/hole injection layer/hole transport layer/electron blocking layer/host material and guest material/hole blocking layer/electron Transport layer/electron injection layer/cathode.

The structure of the organic electroluminescence blue phosphorescent device is: transparent anode/hole injection layer/hole transport layer/electron blocking layer/host material and guest material/hole blocking layer/electron transport layer/electron injection layer/cathode, emitting light The layer is composed of host material and metal ligand phosphorescent material doped, the host material of the light-emitting layer is the compound described in claim 1, and the guest material is blue light metal complex.

The structure of the organic electroluminescent green phosphorescent device is: transparent anode/hole injection layer/hole transport layer/electron blocking layer/host material and guest material/hole blocking layer/electron transport layer/electron injection layer/cathode, emitting light The layer is composed of a host material and a metal ligand phosphorescent material doped, the host material of the light-emitting layer is the compound described in claim 1, and the guest material is a metal complex green phosphorescent material.

The structure of the organic electroluminescent phosphorescent device is: transparent anode/hole injection layer/hole transport layer/electron blocking layer/host material and guest material/hole blocking layer/electron transport layer/electron injection layer/cathode, light-emitting layer It consists of a host material and a dopant material, the host material of the light-emitting layer is the compound described in claim 1, and the guest material is a metal complex red phosphorescent material.

Relevant characterization: through nuclear magnetic resonance (NMR), gas chromatography-mass spectrometry (GC-MS), electrospray mass spectrometry (MSI), the structure of the phosphorus-oxygen host material is characterized; through ultraviolet absorption spectroscopy (UV), fluorescence emission spectroscopy ( PL), electrochemical analyzer (CV), thermogravimetry (DTG) and differential calorimetry (DSC) to characterize the photophysical properties and stability of the material.

Synthesis of the above compounds:

Example 1:

(1) Synthesis of 2-bromo-spirofluorene xanthene

Add dry 2-bromofluorenone (5.0g, 19.3mmol), phenol (18.2g, 192.8mmol) and methanesulfonic acid (5mL, 77.2mmol) into a two-necked round-bottomed flask equipped with a magnet, and add Spherical condenser, closed system, protected from light, replaced nitrogen 3 times, placed in an oil bath, heated to 150°C, and reacted for 5 hours. At the end of the reaction, water (200 mL) was added and stirred. Sodium hydroxide (7.7 g, 192.8 mmol) was added to adjust the pH value to basic, and the solid crude product was obtained by suction filtration. The crude product was eluted with petroleum ether as eluent by silica gel column chromatography to obtain a white solid product (4.8 g). The yield was 60%. ¹ H NMR (400MHz, CDCl ₃ , ppm) δ: 7.783-7.763 (d, 8.0Hz, 1H), 7.667-7.646 (d, 8.4Hz, 1H), 7.5-7.475 (d, 8.0Hz, 1H), 7.406 -7.366(t, 7.6Hz, 1H), 7.285-7.265(d, 8.0Hz, 1H), 7.246-7.19(m, 5H), 7.169-7.15(d, 7.6Hz, 1H), 6.819-6.779(t, 2H), 6.408-6.385 (d, 7.6Hz, 2H). ¹³ CNMR (75MHz, CDCl ₃ ) δ: 157.175, 154.91, 151.466, 138.928, 138.748, 131.329, 129.173, 129.063, 125, 18, 128.276, 0 , 123.617, 122.118, 121.578, 120.217, 117.161, 54.458.mp: 255℃.GC-MS (EI-m/z): 410[M ⁺ ].

(2) Synthesis of 2-diphenylphosphine-spirofluorene xanthene

Take the dried 2-bromo-spirofluorene xanthene (2.0g, 4.86mmol) and add it into a dried two-necked round-bottomed flask, immediately close the system, and then pump the nitrogen for 3 times, then add refined tetrahydrofuran (50mL) to dissolve sample. Put the system under low temperature conditions (dry ice acetone, -78°C), cool down for 10 minutes, then slowly add n-butyllithium hexane solution (4.6mL, 7.3mmol, 1.6M) dropwise, after the dropwise addition, react at low temperature After 30 minutes, a lithium salt will be formed, and diphenylphosphorous chloride (0.9 mL, 7.3 mmol) is dropped into the system at low temperature (-78° C.) and reacted overnight. Post-treatment was quenched by adding water (50 mL), extracted with ethyl acetate (30 mL×3), dried over anhydrous sodium sulfate, filtered with suction, and the filtrate was concentrated by rotary evaporation. The crude product was obtained as a pale yellow solid, which was used.

(3) Synthesis of 2-diphenylphosphine-spirofluorene xanthene (SFX2PO)

Put the crude product of 2-diphenylphosphine-spirofluorene xanthene in a round bottom flask, dissolve it with dichloromethane (50mL), and slowly add hydrogen peroxide (1.7mL, 14.6mmol) dropwise under ice-cooling (0°C) , reacted for 10 hours. Aftertreatment, the product was spin-dried, put into a vacuum drying oven and dried at 60° C. for 2 hours, and then washed with petroleum ether: ethyl acetate=1:1 as eluent through silica gel column chromatography to obtain a white solid product ( 1.26 g), the yield was 50%. ¹ HNMR (400MHz, DMSO, ppm) δ: 8.139 (t, 1H, 2.16, 7.76), 8.06 (d, 1H, 7.6), 7.573-7.387 (m, 13H), 7.316 (t, 1H, 7.5), 7.251 (t, 4H, 8.0), 7.120 (d, 1H, 7.598), 6.834 (m, 2H), 6.282 (d, 2H, 7.568), mp: 258°C. GC-MS (EI-m/z): 532 [M ⁺ ].

(4) Synthesis of 2,7-dibromo-spirofluorene xanthene

Add dry 2,7-dibromofluorenone (6g, 17.8mmol), phenol (16.7g, 177.5mmol), and methanesulfonic acid (4.6mL, 71.0mmol) into a two-neck round bottom flask equipped with a magnet , add a spherical condenser, close the system, avoid light, pump nitrogen for 3 times, place in an oil bath, heat up to 150°C, and react for 5 hours. At the end of the reaction, water (200 mL) was added and stirred. Sodium hydroxide was added to adjust the pH value to alkaline, and the solid crude product was obtained by suction filtration. The crude product was eluted with petroleum ether as eluent by silica gel column chromatography to obtain a white solid product (4.8 g). The yield was 50%. ¹ H NMR (400MHz, CDCl ₃ , ppm) δ: 7.642-7.621 (d, 8.0Hz, 2H), 7.514-7.49 (d, 8.0Hz, 2H), 7.272-7.239 (m, 6H), 6.849-6.808 ( m, 2H), 6.4-6.379 (d, 7.6Hz, 2H), mp: 266°C. GC-MS (EI-m/z): 488[M ⁺ ].

(5) Synthesis of 2,7-bisdiphenylphosphine-spirofluorene xanthene

Take the dried 2,7-dibromo-spirofluorene xanthene (3.0 g, 6.1 mmol), add it to a dried two-necked round-bottomed flask, immediately close the system, pump nitrogen for 3 times, add refined tetrahydrofuran ( 70 mL) to dissolve the sample. Put the system under low temperature conditions (dry ice acetone, -78°C), cool down for 10 minutes, then slowly add n-butyllithium hexane solution (5.7mL, 9.2mmol, 1.6M) dropwise, after the dropwise addition, react at low temperature After 2 hours, a lithium salt will be formed, and diphenylphosphine chloride (1.1 mL, 9.2 mmol) is dropped into the system at low temperature (-78° C.) and reacted overnight. Post-processing was quenched by adding water (70 mL), extracted with ethyl acetate (30 mL×3), dried over anhydrous sodium sulfate, filtered with suction, and the filtrate was concentrated by rotary evaporation. The crude product was obtained as a pale yellow solid, which was used.

(6) Synthesis of 2,7 bis-diphenylphosphine-spirofluorene xanthene (SFX27PO)

The crude product of 2,7-bisdiphenylphosphine-spirofluorene xanthene was placed in a round bottom flask, dissolved in dichloromethane (70 mL), and hydrogen peroxide (2.1 mL, 18.3mmol), reacted for 10 hours. After treatment, the product was spin-dried, put in a vacuum drying oven and dried at 60°C for 2 hours, and then rinsed with petroleum ether: ethyl acetate: ethanol = 2:2:1 as eluent through silica gel column chromatography to obtain a white Solid product (2.02g), 47% yield. It should be noted that during the column chromatography separation process, the obtained by-product contains a small amount of 2-diphenylphosphinoxy-spirofluorene xanthene, ¹ HNMR (400MHz, DMSO, ppm) δ: 8.225 (dd, 2H, 2.389Hz, 7.916Hz), 7.551-7.639(m, 6H), 7.408-7.512(m, 18H), 7.248-7.269(m, 4H), 6.847-6.887(m, 2H), 6.314(d, 2H, 7.58 Hz)mp: greater than 300°C. ESI-MS: 732[M ⁺ ]. It should be noted that: in the separation process of 2,7 bis-diphenylphosphinoxy-spirofluorene xanthene, the obtained by-product contains A small amount of 2-diphenylphosphino-spirofluorene xanthene.

(7) Synthesis of 2', 7'-dibromo-spirofluorene xanthene

Add dry 9-fluorenone (5g, 27.8mmol), p-bromophenol (24.7g, 138.7mmol), and methanesulfonic acid (7.21mL, 110.9mmol) into a two-necked round-bottomed flask equipped with a magnet, and add Install a spherical condenser tube, close the system, avoid light, pump nitrogen for 3 times, place in an oil bath, raise the temperature to 150°C, and react for 5 hours. At the end of the reaction, water (200 mL) was added and stirred. Sodium hydroxide was added to adjust the pH value to alkaline, and the solid crude product was obtained by suction filtration. The crude product was washed with petroleum ether as eluent by silica gel column chromatography to obtain a white solid product (3.4 g) with a yield of 30%. ¹ HNMR (400MHz, DMSO, ppm) δ: 8.02(d, 2H, 7.618Hz), 7.434-7.491(m, 4H), 7.321-7.281(t, 4H, 8.77Hz), 7.148(d, 2H, 7.56Hz ), 6.265(d, 2H, 2.39Hz).mp: 260, GC-MS(EI-m/z): 488[M ⁺ ].

(8) Synthesis of 2'-diphenylphosphine-spirofluorenoxanthene and 2',7'-bisdiphenylphosphorus-spirofluorenexanthene

Take the dried 2',7'-dibromo-spirofluorene xanthene (2.0g, 4.1mmol), add it into a dried two-necked round-bottomed flask, close the system immediately, change the nitrogen for 3 times, add the refined Tetrahydrofuran (70 mL) dissolved the sample. Put the system under low temperature conditions (dry ice acetone, -78°C), cool down for 10 minutes, then slowly add n-butyllithium hexane solution (3.8mL, 6.1mmol, 1.6M) dropwise, after the dropwise addition, react at low temperature After 2 hours, a lithium salt will be formed, and diphenylphosphorous chloride (0.7 mL, 6.1 mmol) is dropped into the system at low temperature (-78° C.) and reacted overnight. Post-processing was quenched by adding water (70 mL), extracted with ethyl acetate (30 mL×3), dried over anhydrous sodium sulfate, filtered with suction, and the filtrate was concentrated by rotary evaporation. The crude product was obtained as a pale yellow solid, which was used.

(9) Synthesis of 2'-diphenylphosphinoxy-spirofluorenoxanthene (SFX2'PO) and 2',7'-bisdiphenylphosphinoxy-spirofluorenoxanthene (SFX2'7'PO)

The crude product obtained in the previous reaction was placed in a round-bottomed flask, dissolved in dichloromethane (70 mL), and hydrogen peroxide (1.6 mL, 14.4 mmol) was slowly added dropwise under ice-cooling (0° C.) for 10 hours of reaction. After treatment, the product was spin-dried, put in a vacuum drying oven and dried at 60°C for 2 hours, and then rinsed with petroleum ether: ethyl acetate = 1:1 as eluent through silica gel column chromatography to obtain a white solid product 2'- Diphenylphosphoroxy-spirofluorene xanthene (0.7g), yield (64%), ¹ HNMR (400MHz, DMSO, ppm) δ: 7.919 (d, 2H, 7.593), 7.519 (m, 2H, 1.32, 7.40), 7.438(m, 1H, 2.6, 8.4), 7.41-7.36(m, 6.5H), 7.34-7.28(m, 6.8H), 7.23(m, 2.3H, 1.08, 7.67), 7.09( d, 2H, 7.58), 6.89-6.85(m, 1H), 6.608(m, 1H, 1.9, 10.25), 6.277(m, 1H, 1.43, 7.83), mp: 230℃.GC-MS(m/z ): 532[M ⁺ ]., increase the polarity of the eluent, use petroleum ether: ethyl acetate: ethanol = 1:2 to do the eluent elution, and obtain the white solid product 2', 7'-diphenyl Phosphoroxy-spirofluorenoxanthene (0.4 g), yield 27%. 1HNMR (400MHz, DMSO, ppm) δ: 7.864(d, 2H, 7.6), 7.54-7.47(m, 6H), 7.413-7.351(m, 12H, 7.324-7.277(m, 8.5H), 7.229(m, 2H, 0.64, 7.68), 7.13 (d, 2H, 7.55), 6.613 (m, 2H, 1.81, 10.28), mp: 299°C. ESI-MS (m/z): 732[M+].

Example two: the ultraviolet absorption spectrum of (the product in embodiment 1), photoluminescence spectrum, spectral thermal stability and quantum efficiency measurement

(1) Dissolve SFX2PO in dichloromethane dilute solution, and use Shimadzu UV-3150 ultraviolet-visible spectrometer and RF-530XPC fluorescence spectrometer to measure the absorption and emission spectra. The photoluminescence spectrum was measured at the maximum absorption wavelength (312 nm) of ultraviolet absorption. The solid film is formed by dropping the solution on a transparent glass plate after the solvent evaporates. The maximum absorption peak of the SFX2PO solution is 312nm, and the emission peaks of the fluorescence spectrum are 319nm and 332nm. The maximum emission wavelength of the solid film is 369nm. See attached drawing 5 for details.

(2) Dissolve SFX27PO in dichloromethane dilute solution, and use Shimadzu UV-3150 ultraviolet-visible spectrometer and RF-530XPC fluorescence spectrometer to measure the absorption and emission spectra. The photoluminescence spectrum was measured at the maximum absorption wavelength (305 nm) of ultraviolet absorption. The solid film is formed by dropping the solution on a transparent glass plate after the solvent evaporates. The maximum absorption peak of SFX27PO solution is 305nm, and the emission peaks of fluorescence spectrum are 364nm and 381nm. The maximum emission wavelength of the solid film is 374nm. See attached drawing 6 for details.

(3) SFX2'PO was dissolved in dichloromethane dilute solution, and the absorption and emission spectra were measured by Shimadzu UV-3150 ultraviolet-visible spectrometer and RF-530XPC fluorescence spectrometer. The photoluminescence spectrum was measured at the maximum absorption wavelength (304 nm) of ultraviolet absorption. The solid film is formed by dropping the solution on a transparent glass plate after the solvent evaporates. The maximum absorption peak of SFX27PO solution is 304nm, and the emission peaks of fluorescence spectrum are 310nm and 321nm. The maximum emission wavelength of the solid film is 328nm. See attached drawing 7 for details.

(4) Dissolve SFX2'7'PO in dichloromethane dilute solution, and use Shimadzu UV-3150 ultraviolet-visible spectrometer and RF-530XPC fluorescence spectrometer to measure the absorption and emission spectra. The photoluminescence spectrum was measured at the maximum absorption wavelength (304 nm) of ultraviolet absorption. The solid film is formed by dropping the solution on a transparent glass plate after the solvent evaporates. The maximum absorption peak of SFX27PO solution is 304nm, and the emission peaks of fluorescence spectrum are 310nm and 321nm. The maximum emission wavelength of the solid film is 325nm. See attached drawing 8 for details.

Example 3: Preparation of electrophosphorescent devices of SFX2PO, SFX27PO, SFX2'PO and SFX2'7'PO

As shown in Figure X, the structure of a phosphorescent device comprising a spirofluorenexanthene-phosphorus-oxygen host material. Can include glass and conductive glass (ITO) substrate layer 1, hole injection layer 2 (molybdenum oxide MoO3), hole transport layer 3 (m-MTDATA:), light emitting layer 4 (host material and guest light emitting layer), electron transport Layer 5 (BPhen), electron injection layer (KBH4), cathode layer (aluminum Al)

Structure of green phosphorescent device 1: ITO/MoOx(2nm)/m-MTDATA:MoOx(15wt.%, 30nm)/m-MTDATA(10nm)/Ir(ppz)3(10nm)/SFX-2-dpop:Ir (ppy)2(acac)(6wt.%, 20nm)/BPhen(30nm)/KBH4(1nm)

Structure of green phosphorescent device 2: ITO/MoOx(2nm)/m-MTDATA:MoOx(15wt.%, 30nm)/m-MTDATA(10nm)/Ir(ppz)3(10nm)/SFX-2, 7-Didpop :Ir(ppy)2(acac)(6wt.%, 20nm)/BPhen(30nm)/KBH4(1nm)

The structure of the green phosphorescent device 3: ITO/MoOx(2nm)/m-MTDATA:MoOx(15wt.%, 30nm)/m-MTDATA(10nm)/Ir(ppz)3(10nm)/SFX-2'-dpop: Ir(ppy)2(acac)(6wt.%, 20nm)/BPhen(30nm)/KBH4(1nm)

The structure of the green phosphorescent device 4: ITO/MoOx (2nm)/m-MTDATA: MoOx (15wt.%, 30nm)/m-MTDATA (10nm)/Ir(ppz)3(10nm)/SFX-2', 7' -Didpop: Ir(ppy)2(acac)(6wt.%, 20nm)/BPhen(30nm)/KBH4(1nm)

The structure of blue phosphorescent device 1: ITO/MoOx(2nm)/m-MTDATA:MoOx(15wt.%, 30nm)/m-MTDATA(10nm)/Ir(ppz)3(10nm)/SFX-2-dpop: FIrpic(10wt.%, 20nm)/BPhen(20nm)/KBH4(1nm)

The structure of the blue phosphorescent device 2: ITO/MoOx (2nm)/m-MTDATA:MoOx (15wt.%, 30nm)/m-MTDATA (10nm)/Ir(ppz)3(10nm)/SFX-2,7- Didpop: FIrpic (10wt.%, 20

nm)/BPhen(20nm)/KBH4(1nm)

Structure of blue phosphorescent device 3: ITO/MoOx(2nm)/m-MTDATA:MoOx(15wt.%, 30nm)/m-MTDATA(10nm)/Ir(ppz)3(10nm)/SFX-2'-dpop :FIrpic(10wt.%, 20nm)/BPhen(20nm)/KBH4(1nm)

The structure of blue phosphorescent device 4: ITO/MoOx (2nm)/m-MTDATA: MoOx (15wt.%, 30nm)/m-MTDATA (10nm)/Ir(ppz) 3 (10nm)/SFX-2 ', 7 '-Didpop: FIrpic(10wt.%, 20nm)/BPhen(20nm)/KBH4(1nm)

Claims (10)

1. A spirofluorene xanthene phosphorus oxygen-based electrophosphorescent host material, characterized in that the material is a diphenylphosphoryl group introduced at different positions of spirofluorene xanthene, and its structural characteristics are as follows:

Wherein, R ₁ , R ₂ , R ₃ and R ₄ are diphenylphosphine groups or H atoms, but R ₁ , R ₂ , R ₃ and R ₄ cannot be H atoms at the same time. 2. The spirofluorene xanthene phosphorus oxygen-based electrophosphorescent host material according to claim 1, characterized in that R ₁ is a diphenylphosphoryl group, and R ₂ , R ₃ and R ₄ are H atoms, Its structure is as follows:

3. The spirofluorene xanthene phosphorus oxygen-based electrophosphorescent host material according to claim ₁ , characterized in that R and _R are diphenylphosphoryl groups, and R _{and R} are H atoms, Its structure is as follows:

4. The spirofluorene xanthene phosphorus oxygen-based electrophosphorescent host material according to claim 1, wherein R ₃ is a diphenylphosphoryl group, and R ₁ , R ₂ and R ₄ are H atoms, Its structure is as follows:

5. The spirofluorene xanthene phosphorus oxide electrophosphorescent host material according to claim 1, characterized in that R ₃ and R ₄ are diphenylphosphoryl groups, R ₁ and R ₂ are H atoms, and The structure is as follows: 6. A method for preparing a spirofluorenexanthene phosphorus-oxygen electrophosphorescent host material as claimed in claim 2, characterized in that it is a method for preparing compound I, and the specific preparation steps are as follows:

a. At 150°C, 10 times the equivalent of phenol and 2-bromo-9-fluorenone 1 were reacted under the catalysis of methanesulfonic acid for 2 hours, and then the product was separated by silica gel column chromatography to obtain product 2; b. Dissolving 2 in tetrahydrofuran, and performing halide-lithium exchange reaction with n-butyllithium at -78°C for 1 hour to form lithium salt 3; c. At -78°C, add diphenylphosphorus chloride into the above reaction system, react at low temperature for 1 hour, and react at room temperature for 10 hours, then add water to quench the reaction, and extract the reactant with dichloromethane, Finally concentrated to obtain product 4 in the crude product; d. Dissolve the concentrated product with dichloromethane, add 2 times the equivalent of hydrogen peroxide for oxidation, and react for 10 hours. The product is spin-dried with a rotary evaporator and then separated by column chromatography to obtain product 5. 7. A method for preparing the spirofluorenexanthene phosphorus-oxygen electrophosphorescent host material as claimed in claim 3, wherein the specific preparation steps of the compound II are as follows:

a. At 150°C, 10 times the equivalent of phenol and 2,7-dibromo-9-fluorenone 1 were reacted under the catalysis of methanesulfonic acid for 2 hours, and then the product was separated by silica gel column chromatography to obtain product 2; b. Dissolving 2 in tetrahydrofuran, and performing halide-lithium exchange reaction with n-butyllithium at -78°C for 1 hour to form lithium salt 3; c. At -78°C, add diphenylphosphorus chloride into the above reaction system, react at low temperature for 1 hour, and react at room temperature for 10 hours, then add water to quench the reaction, and extract the reactant with dichloromethane, Concentrate finally and obtain containing product 4 and product 5 in the crude product; d. Dissolve the concentrated product with dichloromethane, add 2 times the equivalent of hydrogen peroxide to oxidize, and react for 10 hours. The product is spin-dried with a rotary evaporator and then separated by column chromatography to obtain product 6 and product 7. The mass ratio is 10:1. 8. A method for preparing the spirofluorenexanthene phosphorus oxide electrophosphorescent host material as claimed in claim 4 or 5, wherein the specific preparation steps of compound III and compound IV are as follows:

a. At 150°C, 10 times the equivalent of phenol and 9-fluorenone 1 were reacted under the catalysis of methanesulfonic acid for 2 hours, and then the product was separated by silica gel column chromatography to obtain product 2; b. Dissolving 2 in tetrahydrofuran, and performing halide-lithium exchange reaction with n-butyllithium at -78°C for 1 hour to form lithium salt 3; c. At -78°C, add diphenylphosphorus chloride into the above reaction system, react at low temperature for 1 hour, and react at room temperature for 10 hours, then add water to quench the reaction, and extract the reactant with dichloromethane, Concentrate finally and obtain containing product 4 and product 5 in the crude product; d. Dissolve the concentrated product with dichloromethane, add 2 times the equivalent of hydrogen peroxide for oxidation, and react for 10 hours. The product is spin-dried with a rotary evaporator and then separated by column chromatography to obtain product 6 and product 7. The mass ratio is 1.5:1. 9. An application method of the spirofluorene xanthene phosphorus oxide electrophosphorescent host material as claimed in claim 1, wherein the host material is used in an organic electrophosphorescent light-emitting device, and the structure of the device is: transparent Anode / hole injection layer / hole transport layer / electron blocking layer / host material and guest material / hole blocking layer / electron transport layer / electron injection layer / cathode, the light emitting layer is doped by host material and metal ligand phosphorescent material composition. 10. An application method of the spirofluorenexanthene phosphorus-oxygen electrophosphorescent host material prepared by the preparation method according to claim 7, characterized in that it can be used as a blue or red or green phosphorescent host material with a metal complex The material is doped as the light-emitting layer of the organic electrophosphorescent device. The structure of the device is: transparent anode/hole injection layer/hole transport layer/electron blocking layer/light-emitting layer/hole blocking layer/electron transport layer/electron Injection layer/cathode; wherein the light-emitting layer is a host material and a metal complex blue or red or green phosphorescent material.

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