N, n'-disubstituted dihydrophenazinyl heterocyclic compounds, processes for their preparation and use

Abstract

The application provides an N,N'-disubstituted dihydrophenazine heterocyclic compound and a preparation method and application, the heterocyclic compound has a structure shown in formula I; wherein A is a substituted heterocycle selected from pyridine, pyrazine, pyridazine, quinoline, quinoxaline, phthalazine, benzoxadiazole, benzothiadiazole or benzoselenadiazole; the preparation method is to use N,N'-diaryl diamine and corresponding difluoro heterocyclic derivative as raw materials, to synthesize by nucleophilic aromatic substitution reaction, the method has the advantages of mild reaction condition, simple operation, no metal catalyst is used, overcomes the problems of many isomers, low yield and metal residue in the existing metal catalytic coupling method, provides a general strategy for efficient and green synthesis of target compounds, and the structure of the heterocycle A can be changed to accurately control the photophysical properties of the compound. The compound can be used as a fluorescent probe and can be used for preparing an organic electroluminescent device, and has a wide application prospect in the field of photoelectric functional materials.

Description

Technical Field

[0001] This invention relates to an N,N'-disubstituted dihydrophenazine heterocyclic compound, its preparation method, and its application, belonging to the technical field of organic light-emitting materials preparation and application. Background Technology

[0002] In the design of organic light-emitting materials, precise control of their photophysical properties through molecular structure design is a core approach to improving material performance and application potential. Among numerous control strategies, introducing heteroatoms such as nitrogen, oxygen, and sulfur into the conjugated framework is a particularly effective and widely used method. To achieve targeted optimization of material properties, the introduction method needs to be meticulously designed. By strategically controlling the type, quantity, and precise spatial position of heteroatoms in the aromatic ring framework, the electron donor-acceptor strength, charge transfer characteristics, and intramolecular interactions of the molecule can be systematically adjusted. This allows for continuous, predictable, and precise control of the material's electronic structure and related physicochemical properties, providing a solid chemical foundation for developing advanced materials that meet specific optoelectronic application requirements.

[0003] N,N'-disubstituted dihydrophenazine, namely 9,14-dihydro-9,14-diphenyl-dibenzo[a,c]phenazine (DPAC) and its derivatives, undergo structural deformation upon photoexcitation, transforming from a saddle-shaped conformation to a planar conformation. This transformation is typically accompanied by dual fluorescence emission and an unusually large Stokes shift. Some of these compounds exhibit Stokes shifts greater than 200 nm and unique multi-emission properties (J. Am. Chem. Soc. 2015, 137, 26, 8509–8520), which is relatively rare in organic optoelectronic functional materials. Therefore, the study of their synthesis methods and properties has received high attention from professionals in the field.

[0004] In the prior art, the preparation methods of such compounds usually require the use of copper or palladium-based catalysts to synthesize them via a CN coupling reaction between aryl halides and dihydrophenazine derivatives (Chem. Commun., 2020, 56, 2260), or through related preparation methods provided in invention patent application “Based on N,N'-disubstituted dihydrophenazine compounds and their preparation methods and applications” (application publication number: CN 114031565 A).

[0005] However, for heterocyclic modified dihydrophenazines, due to the influence of the heterocyclic electron push-pull effect, existing preparation methods often yield isomer byproducts, resulting in a significantly lower yield of the target molecule compared to dihydrophenazines without heteroatom modification, or even failure to obtain the target molecule. In addition, existing preparation methods also suffer from problems such as harsh reaction conditions, limited substrate types, long reaction times, and potential contamination of the product by residual metals. Therefore, the types of dihydrophenazine derivatives are greatly limited. Summary of the Invention

[0006] The present invention aims to provide a novel N,N'-disubstituted dihydrophenazine heterocyclic compound, its preparation method, and its application in a specific field.

[0007] To achieve the above objectives, the present invention first provides an N,N'-disubstituted dihydrophenazine heterocyclic compound having the structure shown in Formula I:

[0008] ;

[0009] in:

[0010] A is a substituted heterocycle selected from pyridine, pyrazine, pyridazine, quinoline, quinoxaline, phthalazine, benzoxadiazole, benzothiadiazole, or benzoselenidazole.

[0011] Preferably, the N,N'-disubstituted dihydrophenazine heterocyclic compound provided by the present invention is a compound having one of the following structures:

[0012]

[0013] Right now:

[0014] N,N'-disubstituted dihydrophenazine heterocyclic compounds I-1 and I-10 containing a pyridine ring;

[0015] I-2, an N,N'-disubstituted dihydrophenazine heterocyclic compound containing a pyrazine ring;

[0016] N,N'-disubstituted dihydrophenazine heterocyclic compounds containing a quinoline ring, namely I-3, I-5, I-12 and I-14;

[0017] N,N'-disubstituted dihydrophenazine heterocyclic compounds I-4 and I-6 containing a quinoxaline ring;

[0018] I-11, an N,N'-disubstituted dihydrophenazine heterocyclic compound containing a pyridazine ring;

[0019] N,N'-disubstituted dihydrophenazine heterocyclic compounds I-13 and I-15 containing phthalazine rings;

[0020] N,N'-disubstituted dihydrophenazine heterocyclic compounds I-7, I-8, and I-9, respectively, containing a benzoxadiazole ring, a benzothiadiazole ring, and a benzoselenidazole ring.

[0021] Secondly, this invention also provides a method for preparing the above-mentioned N,N'-disubstituted dihydrophenazine heterocyclic compound, which uses N,N'-diaryldiamine as a starting material, reacts it with a difluoroheterocyclic derivative in a nucleophilic aromatic substitution reaction, and then purifies it to obtain the compound, wherein:

[0022] Its synthetic route is as follows:

[0023] ;

[0024] The difluoroheterocyclic derivative is selected from difluoropyridine, difluoropyrazine, difluoropyridazine, difluoroquinoline, difluoroquinoxaline, difluorophthalazine, difluorobenzoxadiazole, difluorobenzothiadiazole, or difluorobenzoselenidazole;

[0025] The nucleophilic aromatic substitution reaction is carried out in the presence of an acid-binding agent.

[0026] Furthermore:

[0027] The acid-binding agent is sodium hydride, and the molar ratio of N,N'-diaryldiamine to sodium hydride is 1:4;

[0028] The nucleophilic aromatic substitution reaction is carried out in a polar organic solvent, namely N,N'-dimethylformamide, for a reaction time of 6 to 24 hours, and the molar ratio of the N,N'-diaryldiamine to the difluoroheterocyclic derivative is 1:2.

[0029] The purification was performed using rapid silica gel column chromatography. The column packing material was 300-400 mesh silica gel, and the eluent was a mixture of petroleum ether and dichloromethane, with a volume ratio of petroleum ether to dichloromethane of 4:1.

[0030] Based on this, the present invention also provides the application of the above-mentioned N,N'-disubstituted dihydrophenazine heterocyclic compounds as fluorescent probes, and their application in the preparation of organic electroluminescent devices. Compared with the prior art, the outstanding beneficial effects and significant progress of the present invention are as follows:

[0031] First, this invention provides an N,N'-disubstituted dihydrophenazine compound modified by a specific heterocycle (A), wherein A is selected from a series of heterocyclic groups such as pyridine, pyrazine, pyridazine, quinoline, quinoxaline, phthalazine, benzoxadiazole, benzothiadiazole, and benzoselenidazole. Furthermore, this invention provides a general method for the efficient synthesis of this type of compound via a nucleophilic aromatic substitution reaction, and reveals its application potential as a fluorescent probe and in the preparation of organic electroluminescent devices.

[0032] Compared with existing technologies, the preparation method provided by this invention abandons the transition metal-catalyzed CN coupling strategy commonly used in existing technologies, which has poor adaptability to heterocyclic substrates and is prone to generating isomer byproducts. Instead, it innovatively adopts a nucleophilic aromatic substitution reaction between N,N'-diaryldiamine and difluoroheterocyclic derivative. This fundamental change effectively avoids the isomer problem caused by the electron push-pull effect of heteroatoms, significantly improves the purity and yield of the target product, and has better universality and reliability for structure-sensitive heterocyclic modified dihydrophenazine.

[0033] Furthermore, the synthetic route provided by this invention has outstanding features such as mild conditions, simple operation, and environmental friendliness. The reaction does not require the use of expensive and potentially residual metal catalysts such as palladium and copper, thus eliminating metal pollution at the source. This is beneficial for obtaining high-purity optoelectronic materials. Moreover, the reaction can be carried out in commonly used polar solvents with controllable time. Post-processing can be efficiently separated using conventional column chromatography techniques, which greatly reduces the difficulty and cost of preparation and has good prospects for large-scale production.

[0034] Furthermore, this invention employs a systematic "skeleton engineering" strategy to precisely introduce a variety of heterocyclic modules with diverse electronic properties onto the dihydrophenazine skeleton. This modular design enables those skilled in the art to achieve continuous and precise control over the overall electronic structure, charge transfer characteristics, and spatial conformation of the molecule by simply changing the type of heterocycle A. This provides a powerful chemical tool for the directional optimization of the photophysical properties of materials, such as absorption / emission wavelength, Stokes shift, and luminescence efficiency. It significantly broadens the performance control range and structural diversity of dihydrophenazine materials, overcoming the limitation of the structure of products obtained by existing methods.

[0035] In summary, this invention not only provides a series of novel and tunable N,N'-disubstituted dihydrophenazine heterocyclic compounds, but more importantly, it provides an efficient, universal, and clean synthetic route, successfully solving key bottleneck problems in existing preparation technologies. This lays a solid material foundation and methodological support for the in-depth research and practical application of such compounds in high-end optoelectronic functional materials such as fluorescence sensing and organic electroluminescent devices. It has outstanding beneficial effects and significant progress, and is of great value for promotion and application. Attached Figure Description

[0036] To more clearly illustrate the technical solution of the present invention and the technical effects of implementing the present invention, the accompanying drawings used in the embodiments of the present invention will be briefly introduced below.

[0037] Obviously, the accompanying drawings described below are only some of the drawings in the embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without any creative effort, but these other drawings also fall within the scope of drawings required for the embodiments of the present invention.

[0038] Figure 1 The absorption and fluorescence emission spectra of N,N'-disubstituted dihydrophenazine (DPAC) in cyclohexane solution are shown.

[0039] Figure 2 The absorption and fluorescence emission spectra of N,N'-disubstituted dihydrophenazine heterocyclic compound I-1 in cyclohexane solution are shown.

[0040] Figure 3 The absorption and fluorescence emission spectra of N,N'-disubstituted dihydrophenazine heterocyclic compound I-2 in cyclohexane solution are shown.

[0041] Figure 4 The absorption and fluorescence emission spectra of N,N'-disubstituted dihydrophenazine heterocyclic compound I-5 in cyclohexane solution are shown.

[0042] Figure 5 The absorption and fluorescence emission spectra of N,N'-disubstituted dihydrophenazine heterocyclic compound I-6 in cyclohexane solution are shown.

[0043] Figure 6 The fluorescence emission spectrum of N,N'-disubstituted dihydrophenazine (DPAC) in standard rotational viscosity mineral oil;

[0044] Figure 7 The fluorescence emission spectrum of N,N'-disubstituted dihydrophenazine heterocyclic compound I-1 in standard rotational viscosity mineral oil;

[0045] Figure 8 The fluorescence emission spectrum of N,N'-disubstituted dihydrophenazine heterocyclic compound I-2 in standard rotational viscosity mineral oil;

[0046] Figure 9 This is a schematic diagram of the structure of an electroluminescent device prepared using N,N'-disubstituted dihydrophenazine heterocyclic compound I-8 as the main material. Detailed Implementation

[0047] To make the technical solution, beneficial effects and significant progress of the present invention clearer and more comprehensive, the technical solution provided by the present invention will be clearly and completely described below through specific embodiments and their effects. Obviously, all embodiments and their effects described below are only some embodiments and effects of the present invention, and not all of them.

[0048] Based on the embodiments and effects provided by this invention, all other embodiments and effects obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0049] It should be noted that:

[0050] The terms "firstly," "secondly," etc., used in the claims, description, and examples of preparation and effects of the embodiments of this invention are only used to distinguish different objects and not to describe a specific order; furthermore, the term "comprising" and any variations thereof are intended to cover non-exclusive inclusion, for example, including not only a series of listed steps or units of a process, method, system, product, or device, but also optionally steps or units not listed, or optionally other operational steps or units inherent to these processes, methods, products, or devices.

[0051] What needs to be understood is:

[0052] In the description of the embodiments of the present invention, some basic operational terms commonly used in the art are used, such as "stirring" and "dissolving". These terms should be interpreted broadly, that is, they can refer to routine operations performed in the art using various conventional equipment and appliances, or they can refer to operations performed using the latest equipment, such as program-controlled operations and unmanned automatic operations. Unless otherwise explicitly limited, those skilled in the art should understand the specific meaning of the above terms in the present invention according to the specific circumstances and adopt specific operating methods to achieve their operating objectives.

[0053] It should also be noted that:

[0054] The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some implementation cases and comparative examples;

[0055] In addition, all instruments, equipment, raw materials, reagents and standards involved in the following specific embodiments are commercially available unless otherwise specified.

[0056] The technical solution of the present invention will now be described in detail with reference to specific embodiments. Example 1

[0057] This embodiment provides an N,N'-disubstituted dihydrophenazine heterocyclic compound.

[0058] The N,N'-disubstituted dihydrophenazine heterocyclic compounds provided in this embodiment are a class of compounds having the structure shown in Formula I:

[0059] ;

[0060] Wherein, A is a substituted heterocycle selected from pyridine, pyrazine, pyridazine, quinoline, quinoxaline, phthalazine, benzoxadiazole, benzothiadiazole or benzoselenidazole.

[0061] Preferably, the N,N'-disubstituted dihydrophenazine heterocyclic compound provided in this embodiment is a compound having one of the following structures:

[0062]

[0063] Right now:

[0064] N,N'-disubstituted dihydrophenazine heterocyclic compounds I-1 and I-10 containing a pyridine ring;

[0065] I-2, an N,N'-disubstituted dihydrophenazine heterocyclic compound containing a pyrazine ring;

[0066] N,N'-disubstituted dihydrophenazine heterocyclic compounds containing a quinoline ring, namely I-3, I-5, I-12 and I-14;

[0067] N,N'-disubstituted dihydrophenazine heterocyclic compounds I-4 and I-6 containing a quinoxaline ring;

[0068] I-11, an N,N'-disubstituted dihydrophenazine heterocyclic compound containing a pyridazine ring;

[0069] N,N'-disubstituted dihydrophenazine heterocyclic compounds I-13 and I-15 containing phthalazine rings;

[0070] N,N'-disubstituted dihydrophenazine heterocyclic compounds I-7, I-8, and I-9, respectively, containing a benzoxadiazole ring, a benzothiadiazole ring, and a benzoselenidazole ring.

[0071] As can be seen from the above description:

[0072] This embodiment provides an N,N'-disubstituted dihydrophenazine compound modified by a specific heterocycle (A), wherein A is selected from a series of heterocyclic groups such as pyridine, pyrazine, pyridazine, quinoline, quinoxaline, phthalazine, benzoxadiazole, benzothiadiazole and benzoselenidazole. Example 2

[0073] This embodiment provides a method for preparing the N,N'-disubstituted dihydrophenazine heterocyclic compound described in Example 1.

[0074] The preparation method provided in this embodiment uses N,N'-diaryldiamine, also known as N9,N10-diphenylphenanthrene-9,10-diamine (abbreviated as PHNH), as the starting material, and performs a nucleophilic aromatic substitution reaction with a difluoro heterocyclic derivative, followed by purification. The synthetic route is as follows:

[0075] ;

[0076] in:

[0077] The difluoroheterocyclic derivative is selected from difluoropyridine, difluoropyrazine, difluoropyridazine, difluoroquinoline, difluoroquinoxaline, difluorophthalazine, difluorobenzoxadiazole, difluorobenzothiadiazole, or difluorobenzoselenidazole;

[0078] The nucleophilic aromatic substitution reaction is carried out in the presence of sodium hydride as an acid-binding agent, and the molar ratio of the N,N'-diaryldiamine to the sodium hydride is 1:4.

[0079] The nucleophilic aromatic substitution reaction is carried out in the polar organic solvent N,N'-dimethylformamide, and the reaction time is usually 6 to 24 hours, while the molar ratio of N,N'-diaryldiamine to difluoroheterocyclic derivative is 1:2.

[0080] The purification was performed using rapid silica gel column chromatography, wherein the column packing material was 300-400 mesh silica gel, and the eluent was a mixture of petroleum ether and dichloromethane, with a volume ratio of petroleum ether to dichloromethane of 4:1.

[0081] From the above description, it can be seen that:

[0082] The preparation method provided in this embodiment abandons the transition metal-catalyzed CN coupling strategy commonly used in the prior art, which has poor adaptability to heterocyclic substrates and is prone to generating isomer byproducts. It innovatively adopts a nucleophilic aromatic substitution reaction between N,N'-diaryldiamine and difluoroheterocyclic derivative, which effectively avoids the isomer problem caused by the electron push-pull effect of heteroatoms, significantly improves the purity and yield of the target product, and has better universality and reliability for structure-sensitive heterocyclic modified dihydrophenazine.

[0083] Furthermore, the synthesis route provided in this embodiment is mild, easy to operate, and environmentally friendly. The reaction does not require expensive and potentially residual metal catalysts such as palladium and copper, thus eliminating metal pollution at the source. This is beneficial for obtaining high-purity optoelectronic materials. Moreover, the reaction can be carried out in commonly used polar solvents, the time is controllable, and the post-processing is simple, showing good prospects for large-scale production.

[0084] To further aid in understanding the technical solution provided in this embodiment, as well as the specific operation process and technical effects achievable, the preparation method provided in this embodiment will be further explained below through specific preparation examples.

[0085] Of course, those skilled in the art should understand that the preparation examples described below are illustrative rather than restrictive, and should not be construed as limiting the scope of protection claimed by the present invention; and

[0086] The following preparation examples only use some of the preferred proportioning parameters and operating parameters in this embodiment as examples. In fact, the same results can be obtained within the control range of all optional materials, proportioning parameters and operating parameters provided in this embodiment. This embodiment is only for the sake of simplicity and will not be described in detail. Preparation Example 1: Synthesis of N,N'-disubstituted dihydrophenazine heterocyclic compounds I-1 and I-10

[0087] Add 360 mg (1 mmol) of N9,N10-diphenylphenanthrene-9,10-diamine (abbreviation PHNH) and 96 mg (4 mmol) of NaH to a 50 mL three-necked flask;

[0088] After evacuating the three-necked flask and refilling it with nitrogen for three cycles, 20 mL of anhydrous N,N-dimethylformamide was added to the flask, and the mixture was stirred at room temperature for 15 minutes. Then, 1.2 mmol of difluoropyridine, a difluoroheterocyclic derivative dissolved in 3 mL of N,N-dimethylformamide, was added to the flask, and the mixture was stirred at room temperature for 6 hours. The reaction was then quenched with 5 mL of ethanol, and 100 mL of water was added to the mixture. The mixture was filtered, washed with water, and the water was removed under vacuum to obtain the residue. This residue was purified by elution using a rapid silica gel column with 300-400 mesh silica gel packed with a mixture of petroleum ether and dichloromethane in a volume ratio of 4:1. The purified residue yielded N,N'-disubstituted dihydrophenazine heterocyclic compounds I-1 and I-10, respectively.

[0089] The molar yield of the compound shown in Formula I-1 is 60% relative to N,N'-diaryldiamine (PHNH), and the molar yield of the compound shown in Formula I-10 is 54%.

[0090] Testing and verification

[0091] The obtained compound I-1 was analyzed by nuclear magnetic resonance (NMR) and high-resolution mass spectrometry (HRMS), and the characterization data are as follows:

[0092] 1H NMR (600 MHz, Methylene Chloride-d2) δ 8.77-8.72 (m, 2H), 8.39-8.34 (m, 1H), 8.10 (dd, J = 8.3, 1.4 Hz, 1H), 8.01-7.96 (m, 1H), 7.84 (dd, J =8.3, 1.4 Hz, 1H), 7.73-7.68 (m, 2H), 7.68-7.63 (m, 1H), 7.63-7.53 (m, 2H), 7.43-7.38 (m, 1H), 7.28-7.23 (m, 1H), 7.23-7.16 (m, 2H), 7.16-7.09 (m, 2H), 7.09-6.99 (m, 3H), 6.94-6.88 (m, 1H);

[0093] 13 C NMR (151 MHz, Chloroform-d) δ 148.02, 145.47, 143.97, 135.92,135.39, 134.35, 134.31, 130.43, 129.79, 128.98, 128.75, 127.94, 127.02,126.61, 126.37, 126.27, 125.05, 124.17, 123.57, 122.89, 121.93, 121.82,119.36, 117.16;

[0094] HRMS DART (m / z) [M+H] + : calcd. for C 31 H 22 N3 436.1808; Found, 436.1803. Preparation Example 2: Synthesis of N,N'-disubstituted dihydrophenazine heterocyclic compound I-2

[0095] The synthesis method and steps were the same as those in Preparation Example 1 above, except that the difluoroheterocyclic derivative was difluoropyrazine, and the molar yield of I-2 was 83%.

[0096] The characterization data of the obtained compound I-2 are as follows:

[0097] 1H NMR (600 MHz, DMSO-d6) δ 8.92 - 8.88 (m, 1H), 8.30 (s, 1H), 7.76 -7.69 (m, 3H), 7.67 - 7.62 (m, 1H), 7.51 - 7.45 (m, 1H), 7.35 - 7.29 (m, 2H),7.16 - 7.11 (m, 1H);

[0098] 13 C NMR (151 MHz, Chloroform-d) δ 150.12, 145.60, 137.09, 132.36,130.43, 128.88, 127.41, 126.70, 126.28, 124.73, 124.12, 122.87, 121.80;

[0099] HRMS DART (m / z) [M+H] + : calcd. for C 30 H 21 N4 437.1761; Found, 437.1756. Preparation Example 3: Synthesis of N,N'-disubstituted dihydrophenazine heterocyclic compounds I-3, I-5, I-12 and I-14

[0100] The synthesis method and steps were the same as those in Preparation Example 1 above, except that the difluoroheterocyclic derivative was difluoroquinoline. The molar yield of I-3 was 50%, the molar yield of I-5 was 46%, the molar yield of I-12 was 33%, and the molar yield of I-14 was 58%.

[0101] The characterization data of the obtained compound I-3 are as follows:

[0102] 1H NMR (600 MHz, Methylene Chloride-d2) δ 8.89 (dd, J = 4.3, 1.7 Hz, 1H), 8.80 - 8.76 (m, 2H), 8.46 (s, 1H), 8.31 - 8.26 (m, 1H), 8.17 - 8.11 (m,3H), 7.72 - 7.65 (m, 2H), 7.61 - 7.54 (m, 2H), 7.44 (dd, J = 8.2, 4.3 Hz,1H), 7.22 - 7.17 (m, 2H), 7.12 - 7.06 (m, 6H), 6.92 - 6.83 (m, 2H);

[0103] 13 C NMR (151 MHz, Chloroform-d) δ 150.13, 147.49, 146.91, 143.65,137.28, 136.95, 135.54, 130.00, 129.91, 129.14, 128.96, 128.88, 128.83,127.02, 126.61, 126.54, 125.93, 124.59, 124.33, 123.65, 123.03, 122.98,122.02, 121.53, 120.73, 118.06, 116.98;

[0104] HRMS DART (m / z) [M+H] + : calcd. for C 35 H 24 N3 486.1965; Found, 486.1964. Preparation Example 4: Synthesis of N,N'-disubstituted dihydrophenazine heterocyclic compounds I-4 and I-6

[0105] The synthesis method and steps were the same as those in Preparation Example 1 above, except that the difluoroheterocyclic derivative was difluoroquinoxaline. The molar yield of I-4 was 72%, and the molar yield of I-6 was 79%.

[0106] The characterization data of the obtained compound I-4 are as follows:

[0107] 1H NMR (600 MHz, DMSO-d6) δ 8.95 (d, J = 10.4 Hz, 2H), 8.52 (s, 1H), 8.05 (dd, J = 8.3, 1.3 Hz, 1H), 7.75 - 7.69 (m, 1H), 7.65 - 7.59 (m, 1H), 7.31 - 7.25 (m, 2H), 7.23 - 7.16 (m, 2H), 7.00 - 6.94 (m, 1H);

[0108] 13 C NMR (151 MHz, Chloroform-d) δ 147.49, 147.38, 144.81, 141.70,136.69, 130.46, 129.46, 129.13, 127.46, 127.02, 124.82, 124.25, 123.44,122.95, 118.90;

[0109] HRMS DART (m / z) [M+H] + : calcd. for C 34 H 23 N4 487.1917; Found, 486.1914. Preparation Example 5: Synthesis of N,N'-disubstituted dihydrophenazine heterocyclic compound I-11

[0110] The synthesis method and steps were the same as those in Preparation Example 1 above, except that the difluoroheterocyclic derivative was difluoropyridazine, and the molar yield of I-11 was 53%.

[0111] The characterization data of the obtained compound I-11 are as follows:

[0112] 1H NMR (600 MHz, Chloroform-d) δ 9.09 (dd, J = 4.2, 1.8 Hz, 1H), 8.77- 8.72 (m, 2H), 8.63 - 8.57 (m, 1H), 8.23 ​​(dd, J = 8.3, 1.8 Hz, 1H), 8.16 -8.11 (m, 1H), 8.02 (d, J = 8.7 Hz, 1H), 7.84 (d, J = 8.7 Hz, 1H), 7.70 - 7.63 (m, 3H), 7.59 - 7.51 (m, 1H), 7.44 (dd, J = 8.2, 4.2 Hz, 1H), 7.12 - 7.08 (m, 2H), 7.07 - 7.03 (m, 2H), 6.93 - 6.88 (m, 2H), 6.86 - 6.82 (m, 1H), 6.70 -6.64 (m, 3H);

[0113] 13 C NMR (151 MHz, Chloroform-d) δ 130.18, 130.16, 129.55, 128.97,128.34, 126.73, 126.63, 126.45, 126.17, 126.06, 124.44, 123.12, 122.61;

[0114] HRMS DART (m / z) [M+H] + : calcd. for C 35 H 24 N3 487.1965; Found, 486.1961. Preparation Example 6: Synthesis of N,N'-disubstituted dihydrophenazine heterocyclic compounds I-13 and I-15

[0115] The synthesis method and steps were the same as those in Preparation Example 1 above, except that the difluoroheterocyclic derivative was difluorophthalazine. The molar yield of I-13 was 63%, and the molar yield of I-15 was 59%.

[0116] The characterization data of the obtained compound I-13 are as follows:

[0117] 1H NMR (600 MHz, Methylene Chloride-d2) δ 9.01 (d, J = 1.8 Hz, 1H), 8.88 (d, J = 1.8 Hz, 1H), 8.80 - 8.76 (m, 2H), 8.45 (dd, J = 8.0, 1.5 Hz, 1H), 8.29 (d, J = 9.0 Hz, 1H), 8.18 (d, J = 9.0 Hz, 1H), 8.11 (dd, J = 8.3,1.3 Hz, 1H), 7.74 - 7.70 (m, 1H), 7.70 - 7.65 (m, 2H), 7.57 - 7.52 (m, 1H), 7.17 - 7.09 (m, 4H), 6.98 - 6.89 (m, 3H), 6.77 - 6.73 (m, 1H), 6.66 - 6.62 (m, 2H);

[0118] 13 C NMR (151 MHz, Chloroform-d) δ 148.77, 148.37, 147.01, 145.72,144.12, 141.22, 141.07, 140.03, 139.00, 130.57, 130.38, 130.10, 129.69,129.50, 129.34, 128.83, 127.79, 127.74, 127.19, 127.15, 127.00, 125.20,124.85, 123.53, 123.22, 123.19, 120.75, 119.64, 116.19;

[0119] HRMS DART (m / z) [M+H] + : calcd. for C 34 H 23 N4 487.1917; Found, 487.1913. Preparation Example 7: Synthesis of N,N'-disubstituted dihydrophenazine heterocyclic compounds I-7, I-8 and I-9

[0120] The synthesis method and steps were the same as those in Preparation Example 1 above, except that the difluoroheterocyclic derivatives were difluorobenzoxadiazole, difluorobenzothiadiazole and difluorobenzoselenidediazole, respectively. The molar yield of I-7 was 73%, the molar yield of I-8 was 64%, and the molar yield of I-9 was 66%.

[0121] The characterization data of the obtained compound I-7 are as follows:

[0122] 1 H NMR (400 MHz, DMSO-d6) δ: 8.94 (d, J = 8.5 Hz, 2H), 8.45 (s, 2H), 7.96 (d, J = 9.2 Hz, 2H), 7.71 (t, J = 7.8 Hz, 2H), 7.59 (t, J = 7.3 Hz, 2H), 7.37 (d, J = 7.8 Hz, 4H), 7.28 – 7.21 (m, 4H), 7.04 (t, J = 7.2 Hz, 2H);

[0123] 13 C NMR (101 MHz, CDCl3) δ: 148.88, 148.00, 146.27, 134.56, 130.20,129.35, 128.18, 127.23, 126.89, 124.36, 123.47, 123.20, 119.28, 107.90;

[0124] HRMS (ESI, m / z): [M+H] + calcd for C 32 H 21 N4O: 477.1715; found, 477.1714.

[0125] From the description of the above embodiments and preparation examples, it can be seen that:

[0126] The method for preparing N,N'-disubstituted dihydrophenazine heterocyclic compounds provided in this embodiment uses N,N'-diaryldiamine compounds and difluoroheterocyclic derivatives as starting materials. Under mild reaction conditions, the target product is efficiently synthesized through a one-pot reaction. Its characteristic is that the substituent structure of the product can be precisely controlled by selecting fluorinated heterocyclic aromatic hydrocarbons with different types, numbers, and positions of heteroatoms. It can be seen that the synthetic route proposed in this embodiment is simple and efficient, not disclosed in the prior art, and has outstanding substantive features and significant progress, which is highly novel and inventive.

[0127] The significant advantages of the preparation method provided in this embodiment can be summarized as follows:

[0128] First, the products are diverse and have broad application prospects;

[0129] In other words, the preparation method provided in this embodiment can obtain a series of derivatives by flexibly adjusting the raw material structure, which is conducive to expanding its application range in the field of optoelectronic functional materials and meeting the needs of diverse scenarios.

[0130] Secondly, the preparation process is green and environmentally friendly;

[0131] As can be seen, the preparation method provided in this embodiment does not require the use of a metal catalyst in its reaction system, which fundamentally avoids the risk of heavy metal residues in the product and eliminates the potential pollution problems caused by it, resulting in higher product purity.

[0132] Secondly, the process is simple and suitable for industrialization;

[0133] The preparation method provided in this embodiment has mild reaction conditions, short steps, readily available raw materials, low cost, fast reaction rate, high yield, simple post-processing purification, and stable product quality, and has good industrial transformation potential.

[0134] In conclusion, it can be seen that:

[0135] Compared with existing technologies, the preparation method provided by this invention has made substantial progress in terms of technological innovation, process controllability and industrialization feasibility. It also shows obvious advantages in terms of technology, economy and environmental friendliness, has good social benefits and market application prospects, and is of great promotional value.

[0136] It needs to be stated again:

[0137] Although the above preparation examples are mainly prepared using the preferred technical solutions provided in this embodiment, it is fully understood by those skilled in the art that all technical solutions provided in this embodiment, including all optional materials and their ratios, and all operating parameter ranges, can yield the corresponding target product. However, due to different ratios and different operating control parameters, the product yield or product characteristics may fluctuate within a reasonable range. Therefore, this specification only provides a more detailed description of the preparation using the optimized method, and does not provide a detailed description of other possible preparation schemes.

[0138] To further aid in understanding the technical effects achievable by the technical solution provided in this embodiment, the following specific examples will be used to conduct corresponding effect tests and comparisons on the N,N'-disubstituted dihydrophenazine heterocyclic compounds prepared in this embodiment, thereby further illustrating the technical effects achievable by this embodiment. Example 1

[0139] This example demonstrates the fluorescence spectral characteristics of the N,N'-disubstituted dihydrophenazine heterocyclic compound provided in Example 1 of this invention.

[0140] To illustrate the effect of heteroatom effects on molecules sharing the same luminescent parent compound, this example uses N,N'-disubstituted dihydrophenazine heterocyclic compounds I-1, I-2, I-5, and I-6 from Example 1, which are respectively associated with their respective parent molecules, N,N'-disubstituted dihydrophenazine.

[0141] ;

[0142] (DPAC)

[0143] Specifically, it is compared with 9,14-diphenyl-9,14-dihydrodibenzo[a,c]phenazine (abbreviated as DPAC). The specific method is as follows:

[0144] N,N'-disubstituted dihydrophenazine (DPAC), which is already available in the prior art but does not have any heterocyclic substitution, was dissolved in spectroscopically pure cyclohexane to prepare a cyclohexane / DPAC comparison solution with a concentration of 10 μmol / L.

[0145] 3.0 mL of cyclohexane / DPAC contrast solution was added to a 1 cm × 1 cm × 4 cm quartz cuvette equipped with a stirrer. The absorption spectrum was measured using a UV-Vis spectrophotometer. Then, the cuvette was irradiated with a 300 nm monochromatic excitation source while simultaneously measuring its fluorescence emission spectrum. The results are as follows: Figure 1 The absorption and fluorescence emission spectra of N,N'-disubstituted dihydrophenazine (DPAC) in cyclohexane solution are shown, where the horizontal axis represents wavelength and the vertical axis represents absorption and emission intensity.

[0146] Following the same method, the N,N'-disubstituted dihydrophenazine heterocyclic compounds I-1, I-2, I-5 and I-6 prepared in Example 1 above were dissolved in spectroscopically pure cyclohexane to prepare cyclohexane / I-1 sample solution, cyclohexane / I-2 sample solution, cyclohexane / I-5 sample solution and cyclohexane / I-6 sample solution with concentrations of 10 μmol / L, respectively.

[0147] 3.0 mL of the above sample solutions were added to 1 cm × 1 cm × 4 cm quartz cuvettes equipped with stirrers. The absorption spectra of each solution were measured using a UV-Vis spectrophotometer. The sample solutions were then irradiated with a 300 nm monochromatic excitation light source, and their fluorescence emission spectra were measured simultaneously. The results are shown below. Figure 2 The absorption and fluorescence emission spectra of N,N'-disubstituted dihydrophenazine heterocyclic compound I-1 in cyclohexane solution are shown. Figure 3 The absorption and fluorescence emission spectra of N,N'-disubstituted dihydrophenazine heterocyclic compound I-2 in cyclohexane solution are shown. Figure 4The absorption and fluorescence emission spectra of N,N'-disubstituted dihydrophenazine heterocyclic compound I-5 in cyclohexane solution are shown, as well as... Figure 5 The absorption and fluorescence emission spectra of N,N'-disubstituted dihydrophenazine heterocyclic compound I-6 in cyclohexane solution are shown, where the horizontal axis represents wavelength and the vertical axis represents absorption and emission intensity.

[0148] from Figures 2-5 It can be seen from this:

[0149] The N,N'-disubstituted dihydrophenazine heterocyclic compounds I-1, I-2, I-5 and I-6 prepared in Example 1 of this invention show absorption bands at 350-450 nm and redshift as the electron-pushing and pulling ability of the heterocycle increases.

[0150] Notably, heteroatom engineering resulted in significant differences in absorption and photoluminescence.

[0151] As can be seen from Figure 1:

[0152] The parent molecule of N,N'-disubstituted dihydrophenazine heterocyclic compounds, N,N'-disubstituted dihydrophenazine (DPAC), shows an absorption band at 350 nm and two fluorescence emission peaks (404 / 605 nm). The emission at shorter wavelengths is weaker, while the emission at longer wavelengths is broad.

[0153] from Figure 1 , Figure 2 and Figure 3 It can be seen from this:

[0154] The N,N'-disubstituted dihydrophenazine heterocyclic compounds shown in Formulas I-1 and I-2 exhibit emission spectra at room temperature that are significantly different from those of the existing N,N'-disubstituted dihydrophenazine, namely 9,14-diphenyl-9,14-dihydrodibenzo[a,c]phenazine (DPAC), which does not have any heterocyclic substituents. Although they still exhibit weaker short-wavelength emission and broader long-wavelength emission, the long-wavelength emission of the N,N'-disubstituted dihydrophenazine heterocyclic compound shown in Formula I-1 is blue-shifted to 588 nm, while that of the N,N'-disubstituted dihydrophenazine heterocyclic compound shown in Formula I-2 is blue-shifted to 561 nm. This unusual steady-state spectral behavior can be attributed to the heteroatom effect, which enables the modulation of absorption and emission energy levels.

[0155] from Figure 4 and Figure 5 It can be seen from this:

[0156] The emission spectra of the N,N'-disubstituted dihydrophenazine heterocyclic compounds shown in Formulas I-5 and I-6 at room temperature differ significantly from those of existing N,N'-disubstituted dihydrophenazine (DPAC) compounds without any heterocyclic substituents. Specifically, the N,N'-disubstituted dihydrophenazine heterocyclic compounds shown in Formulas I-5 and I-6 exhibit distinct three-band luminescence in cyclohexane. Specifically, the N,N'-disubstituted dihydrophenazine heterocyclic compound shown in Formula I-5 emits light at 400 nm in the first band, 580 nm in the second band, and 760 nm in the third band, corresponding to its structure. In contrast, the N,N'-disubstituted dihydrophenazine heterocyclic compound shown in Formula I-6 emits light at 540 nm in the first band, 630 nm in the second band, and a weaker third band at 770 nm.

[0157] The changes in the number and position of emission peaks demonstrate that the heterocycle successfully influenced the structural evolution of the N,N'-disubstituted dihydrophenazine molecule in the excited state.

[0158] Studies have shown that the three-band luminescence process of the N,N'-disubstituted dihydrophenazine heterocyclic compounds shown in Formula I-5 and Formula I-6 is due to the heterocyclic alteration of the molecular structure after illumination. Specifically, after illumination, the saddle-shaped curved conformation rapidly transforms into an unstable planar conformation and further into a stable twisted conformation, thereby resulting in its three-band luminescence.

[0159] This example successfully demonstrates that:

[0160] Modifying the structure of N,N'-disubstituted dihydrophenazine with heterocycles can alter the luminescent properties of different molecules with the same parent nucleus, particularly changing the position and number of emission peaks.

[0161] It should be noted that:

[0162] Although the above examples only illustrate the spectral characteristics of some N,N'-disubstituted dihydrophenazine heterocyclic compounds provided by this invention in cyclohexane, experiments have demonstrated that other N,N'-disubstituted dihydrophenazine heterocyclic compounds provided by this invention exhibit similar spectral characteristics in other pure organic solutions or mixtures thereof, such as tetrahydrofuran, toluene, ethyl acetate, acetonitrile, dimethyl sulfoxide, methanol, ethanol, and dichloromethane. Further descriptions are omitted here; the above compounds are used only as a general overview to demonstrate the strong universality of the N,N'-disubstituted dihydrophenazine heterocyclic compounds provided by this invention. Example 2

[0163] This example demonstrates the viscosity response characteristics of the N,N'-disubstituted dihydrophenazine heterocyclic compound provided in Example 1 of this invention.

[0164] The luminescent parent molecule of N,N'-disubstituted dihydrophenazine heterocyclic compounds, N,N'-disubstituted dihydrophenazine (DPAC), and the N,N'-disubstituted dihydrophenazine heterocyclic compounds shown in Formula I-1 and Formula I-2 were dissolved in rotational viscosity standard mineral oil of type RTM39, stirred and mixed to fully dissolve, and prepared into homogeneous test solutions with a concentration of 10 μmol / L respectively.

[0165] 1.0 mL of each of the above-mentioned different test solutions was added to a cylindrical high-transparency quartz cuvette. The test solutions were irradiated with a 300 nm monochromatic excitation light source, and the viscosity-response emission spectra of each test solution excited by the 300 nm excitation light source were measured using an Edinburgh FLS1000 fluorescence spectrometer. The results are as follows: Figure 6 The fluorescence emission spectrum of N,N'-disubstituted dihydrophenazine (DPAC) in standard rotational viscosity mineral oil is shown. Figure 7 The fluorescence emission spectrum of N,N'-disubstituted dihydrophenazine heterocyclic compound I-1 in standard rotational viscosity mineral oil is shown, and Figure 8 The fluorescence emission spectrum of N,N'-disubstituted dihydrophenazine heterocyclic compound I-2 in standard rotational viscosity mineral oil is shown. The 300 nm excitation source was generated by continuous white light from a xenon lamp purified by a monochromator. In all emission spectra, the horizontal axis represents wavelength and the vertical axis represents emission intensity.

[0166] from Figures 6-8 From this, we can see that:

[0167] Under high viscosity conditions, the fluorescence emission peaks of N,N'-disubstituted dihydrophenazine (DPAC), N,N'-disubstituted dihydrophenazine heterocyclic compounds shown in Formula I-1 and Formula I-2 all changed significantly. Among them, as the viscosity increased, the short-wavelength emission increased sharply, while the corresponding long-wavelength emission intensity decreased.

[0168] The N,N'-disubstituted dihydrophenazine heterocyclic compound shown in Formula I-1 exhibits dual emission in high-viscosity solutions, with short-wavelength emission at 440 nm and long-wavelength emission close to that in cyclohexane solutions, at approximately 585 nm.

[0169] N,N'-disubstituted dihydrophenazine (DPAC) and the N,N'-disubstituted dihydrophenazine heterocyclic compound shown in Formula I-2 exhibit single emission in high-viscosity solutions. Specifically, the N,N'-disubstituted dihydrophenazine (DPAC) as a comparative example has a short-wavelength emission at 405 nm, while the N,N'-disubstituted dihydrophenazine heterocyclic compound shown in Formula I-2 has a short-wavelength emission at 490 nm.

[0170] The significant influence of polarity on the emission spectra of N,N'-disubstituted dihydrophenazine (DPAC), N,N'-disubstituted dihydrophenazine heterocyclic compounds shown in Formula I-1 and Formula I-2 can be attributed to the influence of viscosity environment on the relaxation process of molecular structure changes from bending to planar and twisting. This demonstrates that the N,N'-disubstituted dihydrophenazine heterocyclic compounds shown in Formula I-1 and Formula I-2 have extremely excellent viscosity response. Example 3

[0171] This embodiment provides the application of the N,N'-disubstituted dihydrophenazine heterocyclic compound described in Example 1.

[0172] First, based on the fact that the N,N'-disubstituted dihydrophenazine heterocyclic compound provided in Example 1 of the present invention has the fluorescence spectral characteristics shown in Example 1 and the viscosity response characteristics shown in Example 2, the N,N'-disubstituted dihydrophenazine heterocyclic compound provided in Example 1 of the present invention can be used as a fluorescent probe.

[0173] Secondly, based on the fluorescence spectral characteristics and viscosity response characteristics of the N,N'-disubstituted dihydrophenazine heterocyclic compound provided in Example 1 of this invention, the N,N'-disubstituted dihydrophenazine heterocyclic compound provided in Example 1 of this invention can be used in the preparation of organic electroluminescent devices.

[0174] like Figure 9 A schematic diagram of the electroluminescent device prepared using N,N'-disubstituted dihydrophenazine heterocyclic compound I-8 as the host material is shown below:

[0175] The structure of the red OLED device prepared using N,N'-disubstituted dihydrophenazine heterocyclic compound I-8 as the host material is as follows:

[0176] ITO / MoO3 (3nm) / TAPC (45nm) / TCTA (5 nm) / Host: Ir(pq)2acac (5 wt%, 20 nm) / TmPyPB (50 nm) / LiF (0.6 nm) / Al (80 nm).

[0177] Specifically, ITO and LiF / Al are used as the anode and cathode of the device, respectively; MoO3 is used as the hole injection layer; Ir(pq)2acac is used as the light-emitting layer; TAPC (4,4'-cyclohexylbis[N,N-di(4-methylphenyl)aniline]) and TCTA (tris(4-carbazole-9-ylphenyl)amine) are used as the hole transport layer and electron blocking layer, respectively; and TmPyPB (1,3,5-tris[(3-pyridyl)-phenyl-3-yl]-benzene) is used as the electron transport layer and hole blocking layer due to its low HOMO energy level (6.7 eV).

[0178] The electroluminescence emission peak of the N,N'-disubstituted dihydrophenazine heterocyclic compound I-8 is in the 600 nm red region, with no other emission peaks; its CIE coordinates are (0.62, 0.38). As the voltage gradually increases from the start-up voltage of 4 V, the current density of the device also increases, but the brightness first increases and then decreases, with a maximum value of 3820 cd / m2. The maximum current efficiency, power efficiency, and external quantum efficiency are 5.3 cd / A, 2.4 lm / W, and 3%, respectively.

[0179] It can be seen that:

[0180] The organic electroluminescent compound N,N'-disubstituted dihydrophenazine heterocyclic compound provided by this invention can be applied in the fields of organic electroluminescent devices, organic solar cells, and organic thin-film transistors.

[0181] In conclusion, it can be seen that:

[0182] First, the N,N'-disubstituted dihydrophenazine heterocyclic compound provided by this invention has a conjugated system with single molecules exhibiting variations from curved to planar and twisted shapes. The electronic and steric effects resulting from heterocyclic substitution influence the molecular structure and energy levels. By introducing different heterocycles to regulate the structural changes of the N,N'-disubstituted dihydrophenazine heterocyclic compound, different molecular structures can be generated, corresponding to different numbers of emission peaks. By regulating the energy levels, different emission peak positions can be generated, covering the emission range from single-band blue light emission to near-infrared red light emission, achieving regulation from single-band emission to three-band emission. This provides different options for the fabrication of viscous fluorescent probes or multi-color organic multifunctional optoelectronic materials and electroluminescent materials.

[0183] Secondly, the N,N'-disubstituted dihydrophenazine heterocyclic compounds provided by this invention can be synthesized in a one-pot manner under mild reaction conditions. The different heterocycles used for modification can be controlled by selecting the corresponding fluoroaromatics. The products are diverse and easy to select. The preparation method is simple, the raw material cost is low, the reaction steps are few, and it is easy to carry out industrial production. It is beneficial to expand and meet the application needs of various scenarios, has excellent social benefits and considerable economic prospects, and has great value for promotion and application.

[0184] In the description process of the above instruction manual:

[0185] The terms “this embodiment,” “this embodiment of the invention,” “this case,” “this comparative example,” “as shown,” “further,” etc., are used to indicate that the specific features, structures, materials, or characteristics described in the embodiment or case or comparative example are included in at least one embodiment or case or comparative example of the present invention.

[0186] In this specification, the illustrative expressions of the above terms are not necessarily directed at the same embodiments, preparation examples, or effect examples. Moreover, the specific features, structures, materials, or characteristics described may be combined or combined in any suitable manner in one or more embodiments, preparation examples, or effect examples.

[0187] Furthermore, without creating contradictions, those skilled in the art can combine or integrate the different embodiments, preparation examples, effect examples, and features described in this specification.

[0188] Finally, it should be noted that:

[0189] The above embodiments and comparative examples are only used to illustrate the technical solutions and effects of the present invention, and are not intended to limit them;

[0190] Although the present invention has been described in detail with reference to the foregoing embodiments, examples, and comparative examples, those skilled in the art should understand that modifications or additions can still be made to the technical solutions or effects described in the foregoing embodiments, examples, and comparative examples, or equivalent substitutions can be made to some or all of the technical features. However, these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions described in the embodiments of the present invention. Non-essential improvements, adjustments, or substitutions made by those skilled in the art based on the content of this specification are all within the scope of protection claimed by the present invention.

Claims

1. An N,N'-disubstituted dihydrophenazine heterocyclic compound, characterized in that, It has the structure shown in Equation I: ； in: A is a substituted heterocycle selected from pyridine, pyrazine, pyridazine, quinoline, quinoxaline, phthalazine, benzoxadiazole, benzothiadiazole, or benzoselenidazole.

2. The N,N'-disubstituted dihydrophenazine heterocyclic compound according to claim 1, characterized in that, Compounds having one of the following structures: Right now: N,N'-disubstituted dihydrophenazine heterocyclic compounds I-1 and I-10 containing a pyridine ring; I-2, an N,N'-disubstituted dihydrophenazine heterocyclic compound containing a pyrazine ring; N,N'-disubstituted dihydrophenazine heterocyclic compounds containing a quinoline ring, namely I-3, I-5, I-12 and I-14; N,N'-disubstituted dihydrophenazine heterocyclic compounds I-4 and I-6 containing a quinoxaline ring; I-11, an N,N'-disubstituted dihydrophenazine heterocyclic compound containing a pyridazine ring; N,N'-disubstituted dihydrophenazine heterocyclic compounds I-13 and I-15 containing phthalazine rings; N,N'-disubstituted dihydrophenazine heterocyclic compounds I-7, I-8, and I-9, respectively, containing a benzoxadiazole ring, a benzothiadiazole ring, and a benzoselenidazole ring.

3. A method for preparing the N,N'-disubstituted dihydrophenazine heterocyclic compound according to claim 1 or 2, characterized in that, The synthetic route for obtaining N,N'-diaryldiamine as the starting material, followed by nucleophilic aromatic substitution reaction with a difluoroheterocyclic derivative and purification, is as follows: 。 4. The preparation method according to claim 3, characterized in that, The difluoroheterocyclic derivative is selected from difluoropyridine, difluoropyrazine, difluoropyridazine, difluoroquinoline, difluoroquinoxaline, difluorophthalazine, difluorobenzoxadiazole, difluorobenzothiadiazole, or difluorobenzoselenidazole.

5. The preparation method according to claim 3, characterized in that, The nucleophilic aromatic substitution reaction is carried out in the presence of an acid-binding agent.

6. The preparation method according to claim 5, characterized in that, The acid-binding agent is sodium hydride, and the molar ratio of N,N'-diaryldiamine to sodium hydride is 1:

4.

7. The preparation method according to claim 3, characterized in that, The nucleophilic aromatic substitution reaction is carried out in a polar organic solvent, namely N,N'-dimethylformamide, and the reaction time is 6 to 24 hours. The molar ratio of the N,N'-diaryldiamine to the difluoroheterocyclic derivative is 1:

2.

8. The preparation method according to claim 3, characterized in that, The purification was performed using rapid silica gel column chromatography. The column was packed with 300-400 mesh silica gel, and the eluent was a mixture of petroleum ether and dichloromethane, with a volume ratio of petroleum ether to dichloromethane of 4:

1.

9. The use of an N,N'-disubstituted dihydrophenazine heterocyclic compound as described in claim 1 or 2 as a fluorescent probe.

10. The use of an N,N'-disubstituted dihydrophenazine heterocyclic compound as described in claim 1 or 2 in the preparation of organic electroluminescent devices.

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