Dinaphthoboroxole Structure Derivatives, Their Preparation Methods and Applications

Abstract

The present invention discloses binaphtho[2,1-d:1',2'-f][1,3,2]dioxaborole structure derivatives, their preparation methods and applications, belonging to the technical fields of organic light-emitting materials and semiconductors. The reaction raw materials of the binaphtho[2,1-d:1',2'-f][1,3,2]dioxaborole structure derivatives are easily available, low in price, the reaction process is conventional, the single-step reaction yield is high, and the cost is low. Using the prepared binaphtho[2,1-d:1',2'-f][1,3,2]dioxaborole structure derivatives as the guest light-emitting material in the light-emitting layer of an OLED device can effectively reduce the roll-off efficiency of the device, improve the light-emitting brightness, and extend the service life of the device.

Description

Technical Field

[0001] The present invention belongs to the technical field of organic luminescent materials and semiconductors, and particularly relates to a dinaphthoboryloxy structure derivative and a preparation method and application thereof. Background Art

[0002] In recent years, organic light-emitting diodes (OLEDs) have become a hot research topic in the lighting and display fields due to their exceptional properties, including spontaneous emission, high brightness, high contrast, see-through, wearable, foldable, low energy consumption, wide viewing angle, and low-temperature resistance. With the advancement of technology, researchers have developed third-generation OLED luminescent materials—thermally activated delayed fluorescence (TADF) materials. TADF materials utilize triplet-to-singlet upconversion, achieving a theoretical internal quantum efficiency of 100%, thus achieving highly efficient luminescence. Classic TADF materials typically consist of a donor-acceptor structure with a significant degree of distortion between the donor and acceptor. This structure reduces the singlet-triplet energy difference, enabling efficient intersystem crossing of triplet excitons, and ultimately achieving exciton utilization of up to 100%. However, due to the large structural relaxation energy during excitation and emission, the emission spectrum of these materials has a half-width (FWHM) of 70-100 nm, which affects the luminescence purity. Therefore, in addition to constructing a highly rigid molecular structure, how to make the molecules have a higher luminous efficiency while obtaining a narrower spectrum is of great significance in the development of OLED materials.

[0003] Currently, the spectral bandwidth issue is being addressed by designing BRB-structured structural compounds, stacking multiple units to form a multi-resonance unit mode. However, multi-resonance TADF materials often have a large singlet-triplet energy level difference, resulting in a low intersystem crossing rate. Ultimately, their application in OLED devices exhibits severe efficiency roll-off (specifically, the decrease in luminous efficiency of electroluminescent devices due to exciton quenching at high current densities) and short device lifetimes, hindering their commercial development. Therefore, this technology still needs improvement and development.

[0004] Chinese published patent CN113402537 A realizes the multiple resonance effect by constructing multiple small B-containing vibration units within the molecule, thereby achieving the maximum possible improvement in the luminescence efficiency of the material without increasing the luminescence wavelength of the material. From the practical results, this method has indeed achieved the expected results at the beginning of material design in terms of wavelength regulation and improving the luminescence efficiency of the material; however, its disadvantages are also obvious. First, the introduction of boron elements into the molecule itself has relatively strict requirements and there are few synthesis methods; if multiple B-containing luminescence units are to be constructed within a single molecule, it is even more difficult from the synthesis perspective. Second, based on the coordination characteristics of boron, in the molecular design of the multiple resonance structure type, the construction of molecules within each subunit is often similar, which results in good planar symmetry, strong rigidity, and easy crystallization of such materials. Such materials exhibit higher boiling points and are more prone to crystallization during use, thus hindering their practical applications. In addition, although the multiple B-R-B configurations have relatively high luminescence efficiency, the luminescence brightness of a single subunit is relatively low, and the luminescence intensity of the overall device is significantly low, with a large gap from the practical promotion and application in the market. Summary of the Invention

[0005] In order to overcome the above-mentioned disadvantages of the prior art, the purpose of the present invention is to provide a dinaphtho[2,1-d:1',2'-f][1,3,2]dioxaborole structure derivative, its preparation method and application, so as to solve the technical problems of harsh synthesis conditions and difficulty in balancing luminescence efficiency and luminescence intensity of existing multiple resonance TADF materials.

[0006] In order to achieve the above purpose, the present invention adopts the following technical solutions:

[0007] In the first aspect of the present invention, a dinaphtho[2,1-d:1',2'-f][1,3,2]dioxaborole structure derivative is disclosed, and its structure is shown in General Formula I:

[0008]

[0009] In the formula:

[0010] is the main structure;

[0011] R1 and R2 are each independently selected from alkenyl groups with 2 to 8 carbon atoms, Si-containing alkenyl groups with 2 to 8 carbon atoms, alkynyl groups with 2 to 8 carbon atoms, Si-containing alkynyl groups with 2 to 8 carbon atoms, aromatic secondary amines with 8 to C 30 substituted or unsubstituted aryl groups with 6 to C 40 or substituted or unsubstituted heteroaryl groups with 4 to C 40 ; the heteroatoms in the substituted or unsubstituted heteroaryl groups with 4 to C 40 are one or more of O, S, N, Si, and Ge, and the substituents are selected from C1 to C 10an alkyl group, a cyano group, an acetonitrile group, an F atom, a D atom, a deuterated methyl group, a deuterated tert-butyl group, a dimethylamino group, a vinyl group, an allyl group, a propenyl group, a styryl group, a cinnamyl group, a phenyl group or a benzyl group;

[0012] The bonding modes of R1 and R2 to the main structure are single-bond linkages.

[0013] In a second aspect of the present invention, a preparation method of the above-mentioned dinaphtho[2,1-d:1',2'-f][1,3,2]dioxaborole structure derivative is disclosed, which includes the following steps:

[0014] Step 1: Using 6-bromo-2-naphthol and p-chlorobenzenesulfonic acid as raw materials, an etherification reaction is carried out through intermolecular dehydration to obtain an intermediate Mn-1;

[0015] Step 2: The intermediate Mn-1 reacts with the active form of iodine through an electrophilic substitution reaction to obtain an intermediate Mn-2;

[0016] Step 3: The intermediate Mn-2 undergoes an intramolecular ring closure under the action of n-butyllithium to obtain an intermediate Mn;

[0017] Step 4: The intermediate Mn undergoes an affinity substitution reaction or a Suzuki reaction to obtain a dinaphtho[2,1-d:1',2'-f][1,3,2]dioxaborole structure derivative.

[0018] In a third aspect of the present invention, the application of the above-mentioned dinaphtho[2,1-d:1',2'-f][1,3,2]dioxaborole structure derivative in the preparation of an electroluminescent device is disclosed.

[0019] In a fourth aspect of the present invention, an electroluminescent device is disclosed, which includes an anode layer, a cathode layer, and a light-emitting layer located between the anode layer and the cathode layer. The light-emitting layer is prepared from a host light-emitting material and a guest light-emitting material, and the guest light-emitting material is selected from the above-mentioned dinaphtho[2,1-d:1',2'-f][1,3,2]dioxaborole structure derivative.

[0020] Preferably, the mass percentage of the guest light-emitting material in the entire light-emitting layer material is 0.1% to 3%.

[0021] Preferably, a hole injection layer, a hole transport layer, and an electron blocking layer are further provided between the anode layer and the light-emitting layer, and a hole blocking layer, an electron transport layer, and an electron injection layer are further provided between the light-emitting layer and the cathode layer.

[0022] In a fifth aspect of the present invention, a display panel is disclosed, and the display panel includes the above-mentioned electroluminescent device.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] The dinaphthoboroxole structure derivative provided by the present invention, in the parent nucleus structure of General Formula I, the 7-position of the main structure six-membered ring is designed as an O atom, the 14-position is designed as a B atom, and at the same time, phenyl substitution is carried out at the 14-position, so that the large π-bond system of the original planar structure becomes a conjugated system with a three-dimensional configuration (as Figure 1 shown). On the one hand, the separation of HOMO and LUMO can be achieved by utilizing the valence electron difference effect between the B atom and the O atom. At the same time, the hybrid fused-ring unit of the B atom and the O atom has a rigid skeleton structure, which can reduce the degree of excited-state structural relaxation, thereby achieving a narrow full width at half maximum. On the other hand, the boron-containing heterocyclic system has a strong electron-withdrawing effect, resulting in a small overlap of the frontier orbitals between the electron donors connected to it, achieving a small energy level difference between the S1 state and the T1 state, and thus realizing reverse intersystem crossing under thermal stimulation conditions. In addition, due to the significant non-symmetrical three-dimensional conformational characteristics of the compound in space, the intermolecular stacking will be reduced during film formation, the film-forming performance will be improved during molecular evaporation deposition, and the luminescence consistency will be significantly improved, thereby effectively improving the device stability and the device yield. Through performance testing, it is proved that when this type of compound is used as the guest luminescent material in the light-emitting layer of an OLED device, it can effectively reduce the roll-off efficiency of the electroluminescent device, improve the luminescence brightness, and extend the service life of the electroluminescent device.

[0025] The preparation method of the dinaphthoboroxole structure derivative provided by the present invention has easily available and low-cost reaction raw materials, a conventional reaction process, a high single-step reaction yield, can effectively control costs, and is expected to achieve large-scale and sustainable production. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a design diagram of the main structure of the dinaphthoboroxole structure derivative of the present invention; among them, arrow 7 indicates the 7-position of the main structure six-membered ring, and arrow 14 indicates the 14-position of the main structure six-membered ring;

[0027] Figure 2 It is a cross-sectional view of the organic electroluminescent device of the present invention;

[0028] Figure 3 It is the NMR spectrum of Compound 1 of the present invention;

[0029] Figure 4 It is the NMR spectrum of Compound 137 of the present invention;

[0030] Figure 5 It is the NMR spectrum of Compound 278 of the present invention;

[0031] Figure 6 It is the NMR spectrum of Compound 386 of the present invention.

[0032] Description of the reference numerals:

[0033] 1 - Substrate layer, 2 - Anode layer, 3 - Hole injection layer, 4 - Hole transport layer, 5 - Electron blocking layer, 6 - Light emitting layer, 7 - Hole blocking layer, 8 - Electron transport layer, 9 - Electron injection layer, 10 - Cathode layer, 11 - Cover layer. Detailed implementation mode

[0034] The following uses specific specific examples to illustrate the implementation modes of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific implementation modes. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention, and all are within the scope of the present invention.

[0035] It should be noted that the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or are inherent to these processes, methods, products, or devices. Moreover, unless otherwise specified, the numbers of each method step are only convenient tools for identifying each method step, rather than limiting the arrangement order of each method step or the scope in which the present invention can be implemented. The change or adjustment of their relative relationships, without substantial change in technical content, should also be regarded as the scope in which the present invention can be implemented.

[0036] In this article, unless otherwise specified, "D" in the structural formula represents "deuterium".

[0037] The present invention provides a dinaphtho[2,1 - d:1',2' - f][1,3,2]dioxaborole structure derivative, and the structure is as shown in General Formula I:

[0038]

[0039] In the formula:

[0040] is the main structure;

[0041] R1 and R2 are each independently selected from C2 - C8 alkenyl, C2 - C8 Si - containing alkenyl, C2 - C8 alkynyl, C2 - C8 Si - containing alkynyl, C8 - C 30 aromatic secondary amines, substituted or unsubstituted C6 - C 40 aryl groups, or substituted or unsubstituted C4 - C 40 heteroaryl groups; the heteroatoms in the substituted or unsubstituted C4 - C 40 heteroaryl groups are one or more of O, S, N, Si, and Ge, and the substituents are selected from C1 - C 10an alkyl group, a cyano group, an acetonitrile group, an F atom, a D atom, a deuterated methyl group, a deuterated tert-butyl group, a dimethylamino group, a vinyl group, an allyl group, a propenyl group, a styryl group, a cinnamyl group, a phenyl group or a benzyl group;

[0042] The bonding modes of R1 and R2 to the main structure are single-bond bonding;

[0043] in the group is the substitution position.

[0044] Preferably, R1 and R2 are each independently selected from any one of the following groups and their derivatives:

[0045]

[0046]

[0047]

[0048]

[0049]

[0050] The present invention provides a preparation method of the above-mentioned dinaphthooxaborole structure derivative, and the reaction formula is as follows:

[0051]

[0052] Step 1: Using 6-bromo-2-naphthol and p-chlorobenzenesulfonic acid as raw materials, etherification reaction is carried out through intermolecular dehydration to obtain intermediate Mn-1;

[0053] Step 2: Iodine can generate an active form of iodine under the action of hydrogen peroxide, and these active forms can undergo an electrophilic substitution reaction with intermediate Mn-1 to obtain intermediate Mn-2;

[0054] Step 3: Intermediate Mn-2 is iodolithiated under the action of n-butyllithium, and then attacks the borate ester to achieve intramolecular cyclization, obtaining intermediate Mn;

[0055] Step 4: Using intermediate Mn as a raw material, through an affinity substitution reaction or a Suzuki reaction, a derivative represented by General Formula I is obtained.

[0056] The present invention provides an organic electroluminescent device, as Figure 2 shown, which sequentially includes a substrate layer 1, an anode layer 2, a hole injection layer 3, a hole transport layer 4, an electron blocking layer 5, a light-emitting layer 6, a hole blocking layer 7, an electron transport layer 8, an electron injection layer 9, a cathode layer 10 and a cover layer 11 from the anode to the cathode direction.

[0057] As the substrate layer 1, it is required to have high mechanical strength, excellent thermal stability, excellent waterproof property, and excellent transparency; preferably, it is prepared from polyethylene terephthalate (PET) plastic.

[0058] As the anode layer 2, generally, in order to enable holes to be smoothly injected into the organic layer, the anode material is preferably a material with a large work function. Specific examples of the anode materials that can be used in the present invention include metals such as vanadium, chromium, copper, zinc, and gold, or their alloys; oxides such as zinc oxide, aluminum oxide, or tin dioxide; conductive polymers such as polypyrrole and polyaniline;

[0059] As the functional organic layer, it includes a hole injection layer 3, a hole transport layer 4, an electron blocking layer 5, a light-emitting layer 6, a hole blocking layer 7, an electron transport layer 8, and an electron injection layer 9. The functional organic layer can be formed on the electrode by various means or methods such as vacuum thermal evaporation, spin coating, printing, etc. The compounds used as the organic layers other than the light-emitting layer 6 can be organic small molecules, organic macromolecules, and polymers, as well as their combinations. The materials used for the hole injection layer 3, the hole transport layer 4, the electron blocking layer 5, the hole blocking layer 7, the electron transport layer 8, and the electron injection layer 9 are selected from the corresponding functional layer materials with excellent cost performance in the industry. The compatibility between the functional layers needs to be determined through a series of testing and screening processes;

[0060] As the material of the hole injection layer 3, MoO3 is preferred;

[0061] As the material of the hole transport layer 4, it can be selected from one of the following materials:

[0062] ;

[0063] As the material of the electron blocking layer 5, it can be selected from one of the following materials:

[0064] ;

[0065] The light-emitting layer 6 is formed by co-evaporation of a host light-emitting material and a guest light-emitting material; among them, the host light-emitting material is selected from , , , or , and the guest light-emitting material is selected from any one of the compounds shown in General Formula 1 with a relatively high triplet energy. The mass fraction of the guest light-emitting material in the entire light-emitting layer 6 is 0.1% - 3.0%.

[0066] As the material of the hole blocking layer 7, it can be selected from ;

[0067] As the material of the electron transport layer 8, one of the following materials can be selected:

[0068] ;

[0069] As the material of the electron injection layer 9, LiF is preferred.

[0070] As the cathode layer 10, generally in order to facilitate the injection of electrons into the functional organic layer, the cathode material is preferably a material with a small work function. Specific examples of the cathode material that can be used in the present invention can be metals such as magnesium, calcium, sodium, potassium, titanium, indium, yttrium, lithium, gadolinium, aluminum, silver, tin, and lead, or their alloys: multi-layer structure materials such as LiF-A1 or LiO2-A1, Mg-Al, Mg-Ag, etc.;

[0071] As the cover layer 11, it can improve the refractive index of the surface of the cathode layer 10 and increase the light extraction rate; preferably Prepare.

[0072] The present invention also provides a method for preparing the above-mentioned organic electroluminescent device. After pretreatment and cleaning, the anode layer 2 is adhered to the substrate layer 1, and then the hole injection layer 3, hole transport layer 4, electron blocking layer 5, light-emitting layer 6, hole blocking layer 7, electron transport layer 8, and electron injection layer 9 with set thicknesses are sequentially evaporated under low-temperature conditions. Then, the cathode layer 10 and the cover layer 11 are sputtered under low-temperature conditions, and finally, the test device is encapsulated by conventional device testing and encapsulation means to obtain the organic electroluminescent device.

[0073] The following will further illustrate the present invention with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and not to limit the scope of the present invention. In addition, it should be understood that after reading the content described in the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims of this application. In addition, those skilled in the art can refer to the preparation method of the above general formula I compound and the following specific embodiments, and combine the intermediates M1 to M4 to prepare Compounds 1 to 401.

[0074] The following embodiments use conventional instrument equipment in the art. For the experimental methods without specific conditions noted in the following embodiments, they are usually carried out under conventional conditions or according to the conditions recommended by the manufacturer. For the process equipment or devices not specifically noted in the following embodiments, conventional equipment or devices in the art are used. For various raw materials used in the following embodiments, unless otherwise stated, conventional commercially available products are used, and their specifications are conventional specifications in the art.

[0075] The structural formula of the representative compound of the dinaphtho[2,1-d:1',2'-f][1,3,2]dioxaborinine structure derivative provided by the present invention is as follows:

[0076]

[0077]

[0078]

[0079]

[0080]

[0081]

[0082]

[0083]

[0084]

[0085]

[0086]

[0087]

[0088]

[0089]

[0090]

[0091]

[0092]

[0093]

[0094]

[0095]

[0096]

[0097]

[0098]

[0099]

[0100]

[0101]

[0102]

[0103]

[0104]

[0105]

[0106]

[0107]

[0108]

[0109]

[0110]

[0111]

[0112]

[0113]

[0114]

[0115] 。

[0116] Example 1 (Synthesis of Compound 1)

[0117]

[0118] Step 1:

[0119] Procedure: Under argon protection, 6-bromo-2-naphthol (223 g, 1.0 mol), 2.0 L of o-dichlorobenzene and p-chlorobenzenesulfonic acid (19.3 g, 0.1 mol) were added to a 5 L three-necked flask. The reaction solution was heated to 180 °C and reacted for 10 h until the reaction was complete. After the reaction was completed, the reaction solution was cooled to room temperature, the reaction solvent was concentrated under reduced pressure, diluted with 3 L of dichloromethane, washed with 3 L of saturated sodium bicarbonate, the organic phase was dried and concentrated, and the residue was purified by silica gel column chromatography (dichloromethane / petroleum ether) to obtain intermediate M1-1, weighing 156 g, with a yield of 73%, HPLC purity of 98%, and LC-MS showing a molecular weight of 429.0.

[0120] Step 2:

[0121] Procedure: Add M1-1 (128 g, 0.3 mol) and 1.5 L of 2-methyltetrahydrofuran solution to a 5-L three-necked flask, stir, add iodine (152 g, 0.6 mol), continue stirring, and slowly add 30% hydrogen peroxide (H2O2; 170 g, 1.5 mol). Stir the reaction mixture at room temperature for 24 h. After the reaction is completed, wash the reaction mixture with 3 L of NaHSO3 and extract with dichloromethane (3 × 2 L). The organic phase is washed with water (1 × 3 L), dried over anhydrous sodium sulfate, concentrated, and the residue is purified by silica gel column chromatography (acetonitrile / n-heptane) to obtain intermediate M1-2, weighing 186 g, with a yield of 91%, an HPLC purity of 98%, and LC-MS showing a molecular weight of 680.7.

[0122] Step 3:

[0123] Procedure: Under argon protection, add M1-2 (170 g, 0.25 mol) and 1.5 L of THF to a 5-L three-necked flask. Cool the reaction solution to below -78 °C and add 2.5 mol / L n-butyllithium (200 mL, 0.5 mol) dropwise. After the addition is complete, continue stirring the reaction solution for 1 h, slowly add a THF solution of 200 mL of dimethyl phenylboronate (37 g, 0.25 mol) dropwise. After the addition is complete, stir the reaction for 1 h, transfer to room temperature, and continue the reaction for 20 h until the reaction is complete. After the reaction is completed, most of the THF is concentrated off at low temperature in the reaction system, diluted with 3 L of dichloromethane, washed with 3 L of water, the organic phase is dried and concentrated, and the residue is purified by silica gel column chromatography (dichloromethane / petroleum ether) to obtain intermediate M1, weighing 51 g, with a yield of 40%, an HPLC purity of 98%, and LC-MS showing a molecular weight of 515.0.

[0124] Step 4:

[0125] Procedure: Under argon protection, add M1 (5.1 g, 0.01 mol), phenylboronic acid (2.6 g, 0.021 mol), 40 mL of THF, 10 mL of H2O, and K2CO3 (5.5 g, 0.04 mol) to a 100-mL three-necked flask. Stir and heat to 40 °C. After the solution becomes clear, add Pd(PPh3)4 (0.2 g, 0.2 mmol), then raise the temperature of the reaction solution to 70 °C and continue the reaction for 12 h until the reaction is complete. Cool the reaction solution to room temperature, extract with ethyl acetate (EA) multiple times, combine the organic phases, dry the organic phase over anhydrous magnesium sulfate, filter and concentrate, and pass through a silica gel column (dichloromethane / petroleum ether) to obtain Compound 1, weighing 4.1 g, with a yield of 80%, an HPLC content of 99%, LC-MS showing a molecular weight of 509.2, and the NMR spectrum is as Figure 3 shown.

[0126] Example 2 (Synthesis of Compound 137)

[0127]

[0128] Step 1:

[0129] Procedure: The synthesis process of M2-1 refers to the synthesis process of M1-1. Replace 6-bromo-2-naphthol (223 g, 1.0 mol) with 7-bromo-2-naphthol (223 g, 1.0 mol) to obtain intermediate M2-1, with a weight of 154 g, a yield of 72%, an HPLC purity of 98%, and LC-MS showing a molecular weight of 429.0.

[0130] Step 2:

[0131] Procedure: The synthesis process of M2-2 refers to the synthesis process from M1-1 to M1-2. Replace M1-1 (128 g, 0.3 mol) with M2-1 (128 g, 0.3 mol) to obtain intermediate M2-2, with a weight of 184 g, a yield of 90%, an HPLC purity of 98%, and LC-MS showing a molecular weight of 680.7.

[0132] Step 3:

[0133] Procedure: The synthesis process of M2 refers to the synthesis process from M1-2 to M1. Replace M1-2 (170 g, 0.25 mol) with M2-2 (170 g, 0.25 mol) to obtain intermediate M2, with a weight of 50 g, a yield of 39%, an HPLC purity of 98%, and LC-MS showing a molecular weight of 515.0.

[0134] Step 4:

[0135] Procedure: Under an inert atmosphere, add M2 (5.1 g, 0.01 mol), deuterated carbazole (3.7 g, 0.021 mol), and 50 mL of toluene into a 100 mL three-necked flask. Stir until the solution is clear, then add Pd2(dba)3 (0.18 g, 0.2 mmol), Am-phos (0.13 g, 0.5 mmol), and sodium tert-butoxide (3.8 g, 0.04 mmol). Heat the reaction solution to 120 °C and continue the reaction for 10 h. After the reaction is completed, filter while hot using diatomaceous earth. Cool the filtrate to room temperature, add purified water for washing, separate the layers and retain the organic phase. Then extract the aqueous phase with ethyl acetate. Combine the organic phases, dry the organic phase with anhydrous magnesium sulfate, concentrate, and column chromatograph (dichloromethane / petroleum ether) to obtain Compound 137, with a weight of 5.3 g, a yield of 76%, an HPLC content of 99%, and LC-MS showing a molecular weight of 703.4. The NMR spectrum is as Figure 4 shown.

[0136] Example 3 (Synthesis of Compound 278)

[0137]

[0138] Step 1:

[0139] Procedure: The synthesis process of M3-1 refers to the synthesis process of M1-1. Replace 6-bromo-2-naphthol (223 g, 1.0 mol) with 3-bromo-2-naphthol (223 g, 1.0 mol) to obtain intermediate M3-1, with a weight of 150 g, a yield of 70%, an HPLC purity of 98%, and LC-MS showing a molecular weight of 429.0.

[0140] Step 2:

[0141] Procedure: The synthesis process of M3-2 refers to the synthesis process from M1-1 to M1-2. Replace M1-1 (128 g, 0.3 mol) with M3-1 (128 g, 0.3 mol) to obtain intermediate M3-2, with a weight of 186 g, a yield of 91%, an HPLC purity of 98%, and LC-MS showing a molecular weight of 680.7.

[0142] Step 3:

[0143] Procedure: The synthesis process of M3 refers to the synthesis process from M1-2 to M1. Replace M1-2 (170 g, 0.25 mol) with M3-2 (170 g, 0.25 mol) to obtain intermediate M3, with a weight of 50 g, a yield of 39%, an HPLC purity of 98%, and LC-MS showing a molecular weight of 515.0.

[0144] Step 4:

[0145] Procedure: Under an inert atmosphere, add M3 (5.1 g, 0.01 mol), 3-trimethylsilylallylboronic acid (3.3 g, 0.021 mol), 50 mL of 1,4-dioxane, K2CO3 (4.1 g, 0.03 mol), and CsF (3.04 g, 0.02 mol) into a 100 mL three-necked flask. Stir until the solution is clear, add Pd2(dppf)Cl2 (0.37 g, 0.5 mmol), heat the reaction solution to 80 °C, and continue the reaction for 16 h. After the reaction is completed, filter while hot using diatomaceous earth, wash the filter cake with ethyl acetate, cool the filtrate to room temperature, add purified water for washing, separate the layers and retain the organic phase, then extract the aqueous phase with ethyl acetate. The organic phase is dried with anhydrous magnesium sulfate, concentrated, and purified by column chromatography (dichloromethane / petroleum ether) to obtain compound 278, with a weight of 4.4 g, a yield of 75%, an HPLC content of 99%, LC-MS showing a molecular weight of 581.3, and the NMR spectrum is as Figure 5as shown

[0146] Example 4 (Synthesis of Compound 386)

[0147]

[0148] Step 1:

[0149] Procedure: The synthesis process of M4-1 refers to the synthesis process of M1-1. Replace 6-bromo-2-naphthol (223 g, 1.0 mol) with 4-bromo-2-naphthol (223 g, 1.0 mol) to obtain intermediate M4-1, weighing 152 g, with a yield of 71%, HPLC purity of 98%, and LC-MS showing a molecular weight of 429.0.

[0150] Step 2:

[0151] Procedure: The synthesis process of M4-2 refers to the synthesis process from M1-1 to M1-2. Replace M1-1 (128 g, 0.3 mol) with M4-1 (128 g, 0.3 mol) to obtain intermediate M4-2, weighing 182 g, with a yield of 89%, HPLC purity of 98%, and LC-MS showing a molecular weight of 680.7.

[0152] Step 3:

[0153] Procedure: The synthesis process of M4 refers to the synthesis process from M1-2 to M1. Replace M1-2 (170 g, 0.25 mol) with M4-2 (170 g, 0.25 mol) to obtain intermediate M4, weighing 49 g, with a yield of 38%, HPLC purity of 98%, and LC-MS showing a molecular weight of 515.0.

[0154] Step 4:

[0155] Procedure: The synthesis process of Compound 386 refers to Step 4 of the synthesis process of Compound 137. Replace M2 (5.1 g, 0.01 mol) with M4 (5.1 g, 0.01 mol), and replace deuterated carbazole (3.7 g, 0.021 mol) with N-methyl-1-(perfluorophenyl)methanamine (4.4 g, 0.021 mol) to obtain Compound 386, weighing 5.7 g, with a yield of 74%, HPLC purity of 99%, and LC-MS showing a molecular weight of 775.2. The NMR spectrum is as Figure 6 as shown

[0156] Prepare the electroluminescent devices of Examples 5 to 15 and Comparative Examples 1 to 3 according to the structure information of the light-emitting layer 6 of the electroluminescent device given in Table 1.

[0157] Table 1 Structures of the Light-Emitting Layer and Hole-Blocking Layer of the Electroluminescent Device

[0158]

[0159] Example 5 (Electroluminescent Device Containing Compound 1)

[0160] An electroluminescent device containing Compound 1, which sequentially includes polyethylene terephthalate (PET) plastic, indium tin oxide (ITO) conductive glass, MoO3, HT-2, EB-2, light-emitting layer 6, HB-2, ET-2, LiF, Al-Mg (Al:Mg = 9:1), and CPL from the anode to the cathode direction;

[0161] Among them, in light-emitting layer 6, PH-3 is used as the host light-emitting material, and Compound 1 is used as the guest light-emitting material, and the mass ratio of PH-3 to Compound 1 is 98:2.

[0162] The preparation method of the above-mentioned electroluminescent device containing Compound 1 includes the following steps:

[0163] 1. Using 1.5 mm PET plastic as substrate layer 1 and 0.15 mm ITO conductive glass as anode layer 2, successively carry out alkali washing, pure water washing, drying, and then ultraviolet-ozone washing to remove organic residues on the surfaces of PET plastic and ITO conductive glass.

[0164] 2. Adhere a layer of ITO conductive glass on the PET plastic, use a vacuum evaporation device to evaporate a 20 nm thick MoO3 as the hole injection layer 3, then evaporate a 45 nm thick HT-2 as the hole transport layer 4, subsequently evaporate a 30 nm thick EB-2 as the electron blocking layer 5, continue to evaporate a 60 nm light-emitting layer 6 formed by PH-3 and Compound 1 with a mass ratio of 98:2 on the EB-2, then continue to evaporate a 10 nm thick HB-2 as the hole blocking layer 7 on the light-emitting layer 6, then continue to evaporate a 30 nm thick ET-2 as the electron transport layer 8, then continue to evaporate a 16 nm thick LiF as the electron injection layer 9 on the electron transport layer 8. After the evaporation of the electron injection layer 9 is completed, sputter a 10 nm thick Al-Mg (Al:Mg = 9:1) alloy as the cathode layer 10 by low-temperature sputtering, and finally continue to evaporate a 40 nm thick CPL as the covering layer 11 on the cathode layer 10.

[0165] 3. Vacuum package the MoO3, HT-2, EB-2, light-emitting layer 6, HB-2, ET-2, and LiF layers to obtain an organic electroluminescent device.

[0166] Example 6

[0167] The difference from Example 5 is that in the light-emitting layer 6, the mass ratio of PH-3 to Compound 1 is 99.9:0.1.

[0168] Example 7

[0169] The difference from Example 5 is that in the light-emitting layer 6, the mass ratio of PH-3 to Compound 1 is 97:3.

[0170] Examples 8 to 17

[0171] The difference from Example 5 is that in the light-emitting layer 6, Compounds 101, 201, 14, 114, 214, 336, 37, 137, 237, and 347 are respectively selected as the guest light-emitting materials of the light-emitting layer 6.

[0172] Comparative Example 1

[0173] The difference from Example 5 is that in the light-emitting layer 6, a traditional material is used as the guest light-emitting material.

[0174] The structure of the electroluminescent device is: PET substrate / ITO / MoO3 (20 nm) / HT-2 (45 nm) / EB-2 (30 nm) / PH-3:C1 = 98:2 (60 nm) / HB-2 (10 nm) / ET-2 (30 nm) / LiF (16 nm) / Al:Mg = 9:1 (10 nm) / CPL (40 nm).

[0175] Comparative Example 2

[0176] The difference from Example 5 is that in the light-emitting layer 6, a traditional material is used as the guest light-emitting material.

[0177] The structure of the electroluminescent device is: PET substrate / ITO / MoO3 (20 nm) / HT-2 (45 nm) / EB-2 (30 nm) / PH-3:C1-16 = 98:2 (60 nm) / HB-2 (10 nm) / ET-2 (30 nm) / LiF (16 nm) / Al:Mg = 9:1 (10 nm) / CPL (40 nm).

[0178] Comparative Example 3

[0179] The difference from Example 5 is that in the light-emitting layer 6, a traditional material is used as the guest light-emitting material, and the mass ratio of the host light-emitting material to the guest light-emitting material is 98:2.

[0180] The structure of the electroluminescent device is: PET substrate / ITO / MoO3 (20 nm) / HT-2 (45 nm) / EB-2 (30 nm) / PH-3:C1-117 = 98:2 (60 nm) / HB-2 (10 nm) / ET-2 (30 nm) / LiF (16 nm) / Al:Mg = 9:1 (10 nm) / CPL (40 nm).

[0181] The electroluminescent devices in the above examples and comparative examples were fabricated into samples of 30 mm × 30 mm. Then, under the same device fabrication process conditions, the anode and cathode were connected using a driving circuit well-known in the industry to characterize the OLED. The lifetime was calculated from the current / voltage / luminance density characteristic curve showing Lambert emission characteristics and measured. The test results are shown in Table 2.

[0182] Table 2 Test Results of Electroluminescent Device Performance

[0183]

[0184] (Note: The current density during the test was 10 mA / cm², and LT95 refers to the time taken for the device luminance to decay to 95% of the initial luminance.)

[0185] As can be seen from the test data in Table 2, 1) compared with the test devices (Comparative Examples 1 to 3) prepared with the host luminescent materials C1, C1-16, and C1-117 in the control group, the test devices prepared with the dinaphtho[2,1-b:1',2'-d]borolane derivatives prepared by this method have obvious advantages in the comprehensive luminous efficiency, the roll-off efficiency is reduced by about 40%, and the service life is extended by about 2 times. 2) Comparing Examples 5 to 7 with Comparative Examples 1 to 3 shows that when the mass ratio of the guest material in the light-emitting layer 6 is in the range of 0.1% to 3%, the comprehensive luminous performance is improved, and the device prepared with the mass ratio of the guest material in the light-emitting layer 6 being 2% has the best luminous performance. 3) When R1 and R2 in the structure shown by General Formula I are perfluorinated substituents, the devices prepared with the corresponding compounds as the guest luminescent materials (Examples 10 to 13) are much better in the comprehensive luminous performance than the electroluminescent devices prepared with R1 and R2 being phenyl substituents (Examples 5 to 9). This may be because fluorine atoms have lone pairs of electrons, which can form p-π conjugation, increasing the activity range of electrons and enhancing the luminous brightness. 4) When the devices prepared with R1 and R2 in the structure shown by General Formula I being fully deuterated substituents (Examples 14 to 17) are compared with the electroluminescent devices prepared with R1 and R2 being phenyl substituents (Examples 5 to 9), the comprehensive luminous performance is significantly improved. This may be because after introducing the "D" atom into the compound molecule, the spin-orbit coupling effect of the compound molecule will be enhanced, which will increase the intersystem crossing (ISC) ability of electrons in the molecule, improve the radiative transition rate of the molecule, and reduce the non-radiative transition rate, thus being beneficial to improving the quantum efficiency of the guest luminescent material.

[0186] The above content is only to illustrate the technical idea of the present invention and cannot be used to limit the protection scope of the present invention. Any modification made on the basis of the technical solution according to the technical idea proposed by the present invention falls within the protection scope of the claims of the present invention.

Claims

1. A method for preparing a dinaphtho-boroxine structure derivative, characterized in that, The following steps are involved: Step 1: Using bromo-2-naphthol and p-chlorobenzenesulfonic acid as raw materials, an etherification reaction is carried out through intermolecular dehydration to obtain the intermediate Mn-1; Step 2: The intermediate Mn-1 reacts with the active form of iodine to obtain the intermediate Mn-2 through electrophilic substitution reaction; Step 3: The intermediate Mn-2 undergoes intramolecular ring closure under the action of n-butyl lithium to obtain the intermediate Mn; Step 4: Using the intermediate Mn as a raw material, obtaining a dinaphthoboryl derivative through affinity substitution reaction or Suzuki reaction; Among them, the structural formulas of intermediate Mn-1, intermediate Mn-2, intermediate Mn, and the dinaphthylboron oxide structure derivative are respectively: , , and ; R1 and R2 are each independently selected from alkenyl groups having 2 to 8 carbon atoms, Si-containing alkenyl groups having 2 to 8 carbon atoms, alkynyl groups having 2 to 8 carbon atoms, Si-containing alkynyl groups having 2 to 8 carbon atoms, aromatic secondary amines having 8 to C 30 , substituted or unsubstituted aryl groups having 6 to C 40 , or substituted or unsubstituted heteroaryl groups having 4 to C 40 ; the heteroatoms in the substituted or unsubstituted heteroaryl groups having 4 to C 40 are one or more of O, S, N, Si, and Ge, and the substituents are selected from alkyl groups having 1 to C 10 , cyano groups, acetonitrile groups, F atoms, D atoms, deuterated methyl groups, deuterated tert-butyl groups, dimethylamino groups, vinyl groups, allyl groups, propenyl groups, styryl groups, cinnamyl groups, phenyl groups, or benzyl groups; the bonding mode of R1 and R2 to the main structure is single-bond bonding.

2. The preparation method of the dinaphtho[2,1-d:1',2'-f][1,3,2]dioxaborole structure derivative according to claim 1, characterized in that, R1 and R2 are independently selected from the following groups and their derivatives: ； Among them, in the group is the substitution position.

3. The dinaphthoboryloxy structure derivative obtained by the preparation method according to claim 1 or 2.

4. Use of the dinaphthoboroxy structure derivative according to claim 3 in the preparation of an electroluminescent device.

5. An electroluminescent device, characterized in that, The invention comprises an anode layer (2), a cathode layer (10), and a light-emitting layer (6) located between the anode layer (2) and the cathode layer (10), wherein the light-emitting layer (6) is made of a host light-emitting material and a guest light-emitting material, and the guest light-emitting material is selected from the dinaphthoborane structure derivative according to claim 3.

6. An electroluminescent device according to claim 5, characterized in that, The mass percentage of the guest luminescent material in the entire luminescent layer (6) is 0.1% to 3%.

7. An electroluminescent device according to claim 5, characterized in that, The host luminescent material is selected from , , , or .

8. An electroluminescent device according to any one of claims 5 to 7, characterized in that, A hole injection layer (3), a hole transport layer (4) and an electron blocking layer (5) are provided between the anode layer (2) and the light-emitting layer (6); and a hole blocking layer (7), an electron transport layer (8) and an electron injection layer (9) are provided between the light-emitting layer (6) and the cathode layer (10).

9. A display panel, characterized in that, The display panel comprises the electroluminescent device according to any one of claims 5 to 8.

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