Spiro[9h-fluorene-9,9'-[9h]xanthene] organic optoelectronic material and preparation method and application thereof

Abstract

The application belongs to the field of organic photoelectric materials, and discloses a kind of spiro [9H-fluorene-9, 9'-[9H] xanthene] derivative organic photoelectric functional material and its preparation method and application. It has the following molecular structure general formula: synthesis by the following method: with 3-bromine diphenyl ether as basic raw material, through ring closing, chlorination reaction to synthesize 6'-bromo-2'-chlorine spiro [9H-fluorene-9, 9'-[9H] xanthene] intermediate, then through amination reaction to synthesize asymmetric disubstituted aniline modified spiro [9H-fluorene-9, 9'-[9H] xanthene] derivative. Reaction condition is mild, cost is low, process operation process is simple, reaction by-product is little, is suitable for industrial production. The compound is applied to the functional material of organic electroluminescent device, especially used as hole transport layer material, hole injection layer material and light emitting host material, can effectively improve the luminous efficiency and service life of device.

Description

Technical Field

[0001] This invention relates to a class of spiro[9H-fluorene-9,9'-[9H]oxanthracene] organic optoelectronic materials, their preparation methods and applications, belonging to the field of organic optoelectronic materials. Background Technology

[0002] Fluorene derivatives possess high triplet and singlet energy levels and fluorescence quantum yields, along with bipolar transport properties. They exhibit good thermal stability and high fluorescence efficiency in both solution and solid states, making them widely used as blue light materials in OLED organic light-emitting materials. Furthermore, fluorene has a rigid planar biphenyl structure, and a series of derivatives with excellent properties can be obtained by introducing functional groups at the C2, C7, and C9 positions of fluorene through molecular design. Among these, spirofluorene materials, due to their unique rigid structure, have attracted considerable attention because their synthesized derivatives all possess high melting and glass transition temperatures, as well as excellent film-forming properties.

[0003] Spirofluoreneoxanthracene consists of a fluorene ring and an oxanthracene ring, with spiro atoms forming at the fluorene ring bridging points. Its unique configuration and steric hindrance suppress molecular stacking, making it suitable for designing amorphous small organic molecules. The spiroconjugation effect reduces the degree of conjugation, facilitating the design of wide-bandgap molecules. The spiro-ring structure enhances molecular rigidity and thermal stability, extending device lifetime. However, most spiro[9H-fluorene-9,9'-[9H]oxanthracene] core structures are synthesized through butyllithium lithiation followed by ring closure, which suffers from high cost and low yield. Therefore, further research and improvement are needed.

[0004] Furthermore, the introduction of polycyclic aromatic hydrocarbons into the spiro[9H-fluorene-9,9'-[9H]oxazanthracene] structure can effectively increase the glass transition temperature of the material, weaken intermolecular forces, maintain good morphological stability of the film, and achieve high fluorescence quantum efficiency. This allows it to be used as a luminescent and hole transport material to compensate for the unbalanced carrier transport capability during the luminescence process. Therefore, this invention aims to design and synthesize a series of novel blue light-emitting materials with advantages such as inexpensive and efficient synthesis routes, excellent thermal stability, suitable HOMO / LUMO energy levels, and hole injection and transport performance by introducing polycyclic aromatic hydrocarbons into spirofluoreneoxazanthracene. These materials can replace existing commercial blue light-emitting materials and be applied to OLED devices. Summary of the Invention

[0005] To improve the luminous efficiency and brightness of organic electroluminescent devices and extend their service life, this invention aims to provide a type of 6'-,2'-position double-substituted asymmetric spiro[9H-fluorene-9,9'-[9H]oxane] with good luminous efficiency and thermal stability; another objective is to provide its preparation method.

[0006] To achieve the objective of this invention, the 6'-,2'-position disubstituted asymmetric spiro[9H-fluorene-9,9'-[9H]oxanthracene] compound of this invention has the following structure:

[0007]

[0008] Where R1 and R2 are each one of the following substituents:

[0009]

[0010]

[0011] Preferred:

[0012]

[0013]

[0014] More preferably, the 6'-,2'-bisubstituted asymmetric spiro[fluorene-9,9'-oxazanthene] of the present invention is a compound with the following structural formula:

[0015]

[0016]

[0017] The synthetic route for the 6'-,2'-position double-substituted asymmetric spiro[fluorene-9,9'-oxazanthene] hole transport material is as follows:

[0018]

[0019] R1 and R2 are the same as above.

[0020] The synthesis steps are as follows: using 3-bromodiphenyl ether and fluorenone as raw materials, the target compound 6'-bromo-2'-chlorospiro[9H-fluoren-9,9'-[9H]oxanthracene] is synthesized through ring closure and chlorination reaction, and then reacted with aniline derivatives to synthesize a series of target compounds.

[0021] The specific steps are as follows:

[0022] (1) Synthesis of 6'-bromo-spiro[9H-fluorene-9,9'-[9H]oxanthracene] compounds

[0023] Under argon protection, 3-bromodiphenyl ether, fluorenone, and methanesulfonic anhydride dissolved in N-methylpyrrolidone (NMP) solvent were added sequentially. Then, [1,3-bis[2,6-bis(1-methylethyl)phenyl]-1,3-dihydro-2H-imidazol-2-ylidene]dichloro(1-phenyl-1H-imidazol-KN3)-(SP-4-1)-palladium (NHC / PdCl2-1-phenylimidazolium) catalyst and potassium carbonate were added. The reaction was heated and stirred. The reaction was detected by high performance liquid chromatography (HPLC). The reaction was quenched with water, extracted with organic solvent, the organic phases were combined, dried, the solvent was recovered under reduced pressure, and recrystallized to obtain intermediate compound a, 6'-bromo-spiro[9H-fluoren-9,9'-[9H]oxanthracene.

[0024] (2) Synthesis of the intermediate 6'-bromo-2'-chlorospiro[9H-fluorene-9,9'-[9H]oxanthracene]

[0025] Using intermediate a as a raw material, N-chlorosuccinimide (NCS) and propylene carbonate as solvents were added to carry out the reaction. After the reaction was completed, water was added to quench the reaction, the organic phases were extracted and combined with organic solvents, dried, and the solvent was evaporated under reduced pressure to obtain the target compound.

[0026] (3) Synthesis of the target compound

[0027] Under argon protection, toluene, 6'-bromo-2'-chlorospiro[9H-fluorene-9,9'-[9H]oxanthracene], intermediate amine derivatives, sodium tert-butoxide, and methanesulfonic acid [n-butyldi(1-adamantyl)phosphine](2-amino-1,1'-biphenyl-2-yl)palladium were added. The mixture was refluxed under argon protection. After the reaction was complete, the reaction was quenched with water, extracted, concentrated under reduced pressure, and recrystallized to obtain the target compound.

[0028] The molar ratio of fluorenone to methanesulfonic anhydride in step (1) is 1:1.0 to 1.2;

[0029] The molar ratio of fluorenone to potassium carbonate in step (1) is 1:1.0 to 4.0;

[0030] The molar ratio of fluorenone to NHC / PdCl2-1-phenylimidazolium catalyst in step (1) is 1:1% to 10%;

[0031] These compounds are functional materials used in organic electroluminescent devices, especially as hole transport layer materials, hole injection layer materials, and light-emitting host materials, which can effectively improve the luminous efficiency and lifespan of the devices.

[0032] The innovations of this invention are as follows: 1. The intermediate 6'-bromo-2'-chlorospiro[9H-fluorene-9,9'-[9H]oxanthracene] is synthesized from 3-bromodiphenyl ether via a two-step reaction involving ring closure and chlorination. A novel nitrogen-heterocyclic carbene catalyst is used in the synthesis of 6'-bromo-spiro[9H-fluorene-9,9'-[9H]oxanthracene], avoiding the conventional lithiation reaction route. The reaction conditions are mild, the cost is low, the process is simple, the yield is high (over 76%), and there are few reaction byproducts, making it suitable for industrial production.

[0033] 2. 6'-Bromo-2'-chlorospiro[9H-fluorene-9,9'-[9H]oxazanthracene] intermediates are a type of bisubstituted asymmetric spiro[9H-fluorene-9,9'-[9H]oxazanthracene] structural derivative. These compounds have a melting point of 223.5℃ and a melting point of 279.5℃ when the weight loss is 5%, exhibiting excellent thermal stability and a high melting temperature. After coupling with aniline derivatives, aniline-modified spiro[9H-fluorene-9,9'-[9H]oxazanthracene] main structures can be synthesized. These structures have good thermal stability prospects and can be used as hole transport layers in organic electroluminescent devices. Attached Figure Description

[0034] Figure 1 Carbon NMR spectrum of the intermediate 6'-bromo-2'-chlorospiro[9H-fluorene-9,9'-[9H]oxanthracene] 13 C NMR;

[0035] Figure 2 1H NMR spectrum of the intermediate 6'-bromo-2'-chlorospiro[9H-fluorene-9,9'-[9H]oxanthracene] 1 H NMR;

[0036] Figure 3 The thermal analysis spectrum of the intermediate 6'-bromo-2'-chlorospiro[9H-fluorene-9,9'-[9H]oxanthracene] by TG-DSC;

[0037] Figure 4 The UV absorption spectrum of the intermediate 6'-bromo-2'-chlorospiro[9H-fluorene-9,9'-[9H]oxanthracene] in dichloromethane. Detailed Implementation

[0038] To better understand the technical solution of this invention, the content of this invention includes, but is not limited to, the specific embodiments described below. Similar techniques and methods should be considered within the scope of protection of this invention. Examples are as follows: Example 1

[0039] (1) Synthesis of 6'-bromo-spiro[9H-fluorene-9,9'-[9H]oxanthracene]

[0040] Under argon protection, fluorenone (0.10 mol, 18.0 g), 3-bromodiphenyl ether (0.11 mol, 27.4 g), and methanesulfonic anhydride (0.10 mol, 17.4 g) dissolved in 150 mL of NMP solvent were added to a 250 mL three-necked flask. Then, NHC / PdCl2-1-phenylimidazolium catalyst (1.0 mmol, 0.7 g) and potassium carbonate (0.10 mol, 13.8 g) were added. The mixture was heated to 150 °C and stirred continuously for 30 h. The reaction was confirmed by high performance liquid chromatography (HPLC). The mixture was quenched with water, extracted three times with dichloromethane (100 mL × 3), and the organic phases were combined, dried, and the solvent was recovered under reduced pressure. Recrystallization yielded 6'-bromo-spiro[9H-fluoren-9,9'-[9H]oxanthracene] (35.0 g, yield 85.0%).

[0041] (2) Synthesis of the intermediate 6'-bromo-2'-chlorospiro[9H-fluorene-9,9'-[9H]oxanthracene]

[0042] In a 250 mL three-necked flask, intermediate 6'-bromo-spiro[9H-fluorene-9,9'-[9H]oxanthracene] (0.05 mol, 20.6 g) was added as a raw material, along with N-chlorosuccinimide (NCS) (0.055 mol, 7.3 g) and 100 mL of propylene carbonate solution. The mixture was stirred until homogeneous and reacted at 5 °C. After the reaction was completed, water was added to quench the reaction. The mixture was extracted three times with dichloromethane (50 mL × 3), the organic phase was washed with water, dried, filtered, and the solvent was recovered under reduced pressure. The mixture was then dispersed in methanol, filtered, and dried to obtain 18.3 g of white solid powder, with a yield of 82.0%.

[0043] 1 H NMR (400MHz, CDCl3), δ / ppm: 7.81 (d, J=7.6Hz, 2H), 7.45~7.38 (m, 3H), 7.24 (dd, J=7.4, 0.9Hz, 2H), 7.15(dd,J=10.1,4.2Hz,4H),6.90(dd,J=8.4,2.0Hz,1H),6.40~6.34(m,1H),6.25(d,J=8.4Hz,1H);

[0044] 13C NMR (100Hz, CDCl3), δ / ppm:153.88,151.60,149.58,139.49,129.27,128.62,128.45,12 8.34,128.31,127.45,126.74,126.26,125.50,123.58,121.08,120.21,119.88,118.23;

[0045] HR-MS(ESI)m / z:Calcd for C 25 H 14 BrClO{[M+H] +}446.9918,found 446.9943

[0046] (3) Synthesis of target compound 4

[0047]

[0048] Under argon protection, 0.1 mol (44.6 g) of 6'-bromo-2'-chlorospiro[9H-fluorene-9,9'-[9H]oxanthracene], 0.12 mol (38.6 g) of intermediate 2-4, 0.5 mol (48.1 g) of sodium tert-butoxide, 0.5 L of toluene, and 1 mmol (0.7 g) of methanesulfonic acid [n-butyldi(1-adamantyl)phosphine](2-amino-1,1'-biphenyl-2-yl)palladium (1 mmol, 0.7 g) were added to a 1 L three-necked flask. The reaction was carried out at 120 °C for 12 h. After cooling, the mixture was hydrolyzed, the organic phase was separated, the mixture was filtered, the filtrate was extracted with toluene, the organic phase was dried over anhydrous magnesium sulfate, concentrated under reduced pressure, and the crude product was purified by column chromatography. The crude product was recrystallized from toluene, filtered, and dried to obtain compound 4 as a white solid powder, totaling 76.8 g, with a yield of 79.1% and a purity of 99.9% (HPLC).

[0049] HR-MS(ESI)m / z:Calcd for C 73 H 50 N₂O{[M+H]} +}971.3925,found 971.3937 Example 2

[0050] (1) Synthesis of 6'-bromo-spiro[9H-fluorene-9,9'-[9H]oxanthracene]

[0051] Under argon protection, fluorenone (50 mmol, 9.0 g), 3-bromodiphenyl ether (50 mmol, 12.5 g), and methanesulfonic anhydride (60 mmol, 10.3 g) dissolved in 80 mL of NMP solvent were added to a 100 mL three-necked flask. Then, NHC / PdCl2-1-phenylimidazolium catalyst (5 mmol, 3.5 g) and potassium carbonate (100 mmol, 13.8 g) were added. The mixture was heated to 150 °C and stirred continuously for 30 h. The reaction was terminated by high performance liquid chromatography (HPLC). The mixture was quenched with water, extracted three times with dichloromethane (100 mL × 3), the organic phases were combined, dried, the solvent was recovered under reduced pressure, and recrystallized to give 6'-bromo-spiro[9H-fluoren-9,9'-[9H]oxanthracene] (17.3 g, yield 84.1%).

[0052] (2) Synthesis of the intermediate 6'-bromo-2'-chlorospiro[9H-fluorene-9,9'-[9H]oxanthracene]

[0053] In a 250 mL three-necked flask, intermediate 6'-bromo-spiro[9H-fluorene-9,9'-[9H]oxanthracene] (20 mmol, 8.2 g) was added as the starting material, along with N-chlorosuccinimide (NCS) (22 mmol, 2.9 g) and 60 mL of propylene carbonate solution. The mixture was stirred until homogeneous and reacted at 5 °C. After the reaction was completed, water was added to quench the reaction. The mixture was extracted three times with dichloromethane (30 mL × 3), the organic phase was washed with water, dried, filtered, and the solvent was recovered under reduced pressure. The mixture was then dispersed in methanol, filtered, and dried to obtain 7.4 g of white solid powder, with a yield of 83.2%.

[0054] (3) Synthesis of target compound 7

[0055]

[0056] Under argon protection, 6'-bromo-2'-chlorospiro[9H-fluorene-9,9'-[9H]oxanthracene] (5 mmol, 2.3 g), intermediate 2-7 (6 mmol, 1.9 g), sodium tert-butoxide (25 mmol, 3.8 g), 50 mL of toluene, and methanesulfonic acid [n-butyldi(1-adamantyl)phosphine](2-amino-1,1'-biphenyl-2-yl)palladium (0.05 mmol, 0.04 g) were added to a 100 mL three-necked flask, and the reaction was carried out at 120 °C for 12 h. After cooling, hydrolysis was performed, the organic phase was separated, the mixture was filtered, the filtrate was extracted with toluene, the organic phase was dried over anhydrous magnesium sulfate, concentrated under reduced pressure, and the crude product was purified by column chromatography. The product was recrystallized from toluene, filtered, and dried, yielding compound 7 as a white solid powder, totaling 37.0 g, with a yield of 76.2% and a purity of 99.9% (HPLC).

[0057] HR-MS(ESI)m / z:Calcd for C 73 H50 N₂O{[M+H]} +}971.1962,found 971.1987 Example 3

[0058] (1) Synthesis of 6'-bromo-spiro[9H-fluorene-9,9'-[9H]oxanthracene]

[0059] Under argon protection, fluorenone (10 mmol, 1.8 g), 3-bromodiphenyl ether (13 mmol, 3.2 g), and methanesulfonic anhydride (11.0 mmol, 1.89 g) dissolved in 50 mL of NMP solvent were added to a 100 mL three-necked flask. Then, NHC / PdCl2-1-phenylimidazolium catalyst (0.5 mmol, 0.33 g) and potassium carbonate (40 mmol, 5.67 g) were added. The mixture was heated to 150 °C and stirred continuously for 30 h. The reaction was confirmed by high performance liquid chromatography (HPLC). The reaction was quenched with water, extracted three times with dichloromethane (50 mL × 3), the organic phases were combined, dried, the solvent was recovered under reduced pressure, and recrystallized to give 6'-bromo-spiro[9H-fluoren-9,9'-[9H]oxanthracene] (3.5 g, yield 86.3%).

[0060] (2) Synthesis of the intermediate 6'-bromo-2'-chlorospiro[9H-fluorene-9,9'-[9H]oxanthracene]

[0061] In a 100 mL three-necked flask, intermediate 6'-bromo-spiro[9H-fluorene-9,9'-[9H]oxanthracene] (10 mmol, 4.1 g) was added as the starting material, along with N-chlorosuccinimide (NCS) (11 mmol, 1.5 g) and 50 mL of propylene carbonate solution. The mixture was stirred until homogeneous and reacted at 5 °C. After the reaction was completed, water was added to quench the reaction. The mixture was extracted three times with dichloromethane (50 mL × 3), the organic phase was washed with water, dried, filtered, and the solvent was recovered under reduced pressure. The mixture was then dispersed in methanol, filtered, and dried to obtain 3.6 g of white solid powder, with a yield of 81.8%.

[0062] (3) Synthesis of target compound 15

[0063]

[0064] Under argon protection, 6'-bromo-2'-chlorospiro[9H-fluorene-9,9'-[9H]oxanthracene] (1 mmol, 0.4 g), intermediate 2-15 (1.2 mmol, 0.5 g), sodium tert-butoxide (5 mmol, 0.5 g), 20 mL of toluene, and methanesulfonic acid [n-butyldi(1-adamantyl)phosphine](2-amino-1,1'-biphenyl-2-yl)palladium (0.01 mmol, 0.007 g) were added to a 50 mL three-necked flask, and the reaction was carried out at 120 °C for 12 h. After cooling, hydrolysis was performed, the organic phase was separated, the mixture was filtered, the filtrate was extracted with toluene, the organic phase was dried over anhydrous magnesium sulfate, concentrated under reduced pressure, and the crude product was purified by column chromatography. The crude product was recrystallized from toluene, filtered, and dried, yielding 0.9 g of compound 15 as a white solid powder, with a yield of 78.2% and a purity of 99.9% (HPLC).

[0065] HR-MS(ESI)m / z:Calcd for C 85 H 58 N₂O{[M+H]} +}1123.3818,found 1123.3854 Application Example 1

[0066] Fabrication of organic electroluminescent devices

[0067] To verify that asymmetric biphenylamine-modified spiro[9H-fluorene-9,9'-[9H]oxanthracene] derivatives can be used as hole transport materials in OLED organic light-emitting devices, OLEDs were prepared using compound 4.

[0068] First, the transparent conductive ITO glass substrate (with an anode on it) (China Nanpo Group Co., Ltd.) is sequentially cleaned with deionized water, ethanol, acetone and deionized water by ultrasonic cleaning, and then treated with oxygen plasma for 30 seconds.

[0069] Then, a 50 nm thick layer of PEDOT:PSS is spin-coated onto ITO as a hole injection layer (PEDOT is a 3,4-ethylenedioxythiophene monomer polymer; PSS is polystyrene sulfonate).

[0070] Then, compound 4 is vapor-deposited to form a 60 nm thick hole transport layer.

[0071] Then, a 40nm thick AND layer was deposited on the hole transport layer as the main body of the light-emitting material layer, and 2% DPAVBi was used as a dopant, with a deposition thickness of 45nm.

[0072] Then, a 40nm thick Alq3 layer was deposited on the light-emitting layer as an electron transport layer.

[0073] Finally, 1 nm LiF was deposited as the electron injection layer and 100 nm Al was deposited as the device cathode.

[0074] Application Example 2: Fabrication of Light-Emitting Device 2

[0075] Replace compound 4 in application example 1 with compound 7.

[0076] Application Example 3: Fabrication of Light-Emitting Device 3

[0077] Replace compound 4 in application example 1 with compound 15.

[0078] Comparative Example 1:

[0079] First, a transparent conductive ITO glass substrate (with an anode) (China Nanpo Group Co., Ltd.) was sequentially ultrasonically cleaned with deionized water, ethanol, acetone, and then deionized water, followed by oxygen plasma treatment for 30 seconds. Next, a 50 nm thick layer of PEDOT:PSS (PEDOT is a 3,4-ethylenedioxythiophene monomer polymer; PSS is polystyrene sulfonate) was spin-coated onto the ITO as a hole injection layer. Then, NPB compound was evaporated to form a 60 nm thick hole transport layer. Next, a 40 nm thick layer of AND was evaporated onto the hole transport layer as the main luminescent material layer, with 2% DPAVBi as dopant, resulting in a 45 nm thickness. Then, a 40 nm thick layer of Alq3 was evaporated onto the luminescent layer as an electron transport layer. Finally, a 1 nm thick layer of LiF was evaporated as an electron injection layer, and a 100 nm thick layer of Al was evaporated as the device cathode.

[0080] The structural formula of the compound in the device is as follows:

[0081]

[0082] The luminescence characteristics of the organic electroluminescent devices prepared in Application Examples 1-4 and Comparative Example 1 are shown in Table 1.

[0083] Table 1

[0084]

[0085] As can be seen, when the asymmetric substituted benzidine-modified spiro[fluorene-9,9'-oxazanthene] hole transport material of the present invention is applied to organic electroluminescent devices, the organic electroluminescent devices exhibit lower driving voltage, higher luminous efficiency and longer lifespan, as well as better durability and reliability.

Claims

1. A method for preparing spiro[9H-fluorene-9,9'-[9H]oxanthracene] compounds, characterized in that, Synthesize using the following steps: (1) Synthesis of 6'-bromo-spiro[9H-fluorene-9,9'-[9H]oxanthracene] compounds Under argon protection, 3-bromodiphenyl ether, fluorenone, and methanesulfonic anhydride dissolved in N-methylpyrrolidone solvent were added sequentially. NHC / PdCl2-1-phenylimidazolium catalyst and potassium carbonate were added, and the reaction was heated and stirred. The reaction was detected by high performance liquid chromatography. The reaction was quenched with water, extracted with organic solvent, the organic phases were combined, dried, the solvent was recovered under reduced pressure, and recrystallized to obtain the intermediate compound 6'-bromo-spiro[9H-fluoren-9,9'-[9H]oxanthracene]. (2) Synthesis of the intermediate 6'-bromo-2'-chlorospiro[9H-fluorene-9,9'-[9H]oxanthracene] Using 6'-bromo-spiro[9H-fluorene-9,9'-[9H]oxanthracene] as the raw material, N-chlorosuccinimide and propylene carbonate were added as solvents for the reaction. After the reaction was completed, water was added to quench the reaction, the organic phases were extracted and combined with organic solvents, dried, and the solvent was evaporated under reduced pressure to obtain 6'-bromo-2'-chlorospiro[9H-fluorene-9,9'-[9H]oxanthracene]. (3) Synthesis of the target compound Under argon protection, toluene, 6'-bromo-2'-chlorospiro[9H-fluorene-9,9'-[9H]oxanthracene], intermediate amine derivatives, sodium tert-butoxide, and methanesulfonic acid [n-butyldi(1-adamantyl)phosphine](2-amino-1,1'-biphenyl-2-yl)palladium were added, and the mixture was refluxed under argon protection. After the reaction was completed, the reaction was quenched with water, extracted, concentrated under reduced pressure, and recrystallized to obtain the target compound. Where R1 and R2 are each one of the following substituents: 。 2. The method for preparing the spiro[9H-fluorene-9,9'-[9H]oxanthracene] compound as described in claim 1, characterized in that, The molar ratio of fluorenone to methanesulfonic anhydride in step (1) is 1:1.0~1.2; The molar ratio of fluorenone to potassium carbonate in step (1) is 1:1.0~4.0; The molar ratio of fluorenone to NHC / PdCl2-1-phenylimidazole catalyst in step (1) is 1:1%~10%.

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