Eight-membered ring fused BODIPY compound and preparation method thereof

Abstract

The invention provides an eight-membered ring fused BODIPY compound and a preparation method thereof, and relates to the technical field of organic functional materials. The core structure of the eight-membered ring fused boron-dipyrromethene compound is a fused skeleton of a double-boron-dipyrromethene unit-anti-aromatic eight-membered ring-anthracene ring, the periphery is modified with 3, 5-di-tert-butylphenyl, and the eight-membered ring fused boron-dipyrromethene compound has excellent stability, near-infrared second-region strong absorption, local anti-aromaticity, double-helix chirality and reversible oxidation-reduction performance. The preparation method comprises the following steps: by taking 2, 7-dibromoanthracene-9-formaldehyde as a precursor, introducing 3, 5-di-tert-butylbenzene at a site 2 through a Suzuki coupling reaction, constructing boron dipyrromethene at a site 9 through condensation, and carrying out a Yamamoto coupling reaction at a site 7 through palladium catalysis, so as to obtain the boron dipyrromethene derivative. And the eight-membered ring fused BODIPY compound is synthesized through intramolecular oxidative dehydrocyclization reaction initiated by ferric trichloride.

Description

Technical Field

[0001] This invention relates to the field of organic functional materials technology, specifically to an eight-membered ring fused fluoroboron dipyrrole compound and its preparation method. Background Technology

[0002] Near-infrared optical materials, with their unique advantages such as strong penetration into deep tissues, low photon energy, and high solar energy utilization efficiency, have shown broad application prospects in cutting-edge fields such as deep biological imaging, photothermal therapy, and near-infrared optoelectronic devices, and have become a research hotspot in the field of organic photofunctional materials.

[0003] Among numerous organic photofunctional molecular systems, fluoroboron dipyrrole (BODIPY) stands out as an ideal molecular framework for constructing novel near-infrared optical materials due to its superior photophysical properties, including a large molar extinction coefficient, high fluorescence quantum yield, narrow absorption and emission half-widths, and excellent chemical stability. The molecular structure of fluoroboron dipyrrole is easily modified, and its photophysical properties can be extended from the visible light region to the near-infrared region through chemical modification, further enhancing the application value of the material.

[0004] Conjugated fusion is one of the effective means to regulate the electronic structure and photophysical properties of fluoroboron dipyrrole. Currently, existing technologies have successfully fused five-membered rings, benzene rings, seven-membered rings, thiophene rings, and other cyclic structures to the fluoroboron dipyrrole framework, and the optical properties of the corresponding derivatives have indeed been improved to some extent. However, the degree of molecular gap regulation is limited after the aromatic structure of the existing fusion unit is conjugated with the fluoroboron dipyrrole framework. The absorption spectra of the derivatives are mostly concentrated in the visible to near-infrared I region, making it difficult to achieve a redshift of the absorption peak tail to the near-infrared II region around 1600 nm. This results in the material failing to meet the core requirement of penetration for applications such as deep biological imaging and long-wavelength near-infrared photodetectors. Existing fusion units such as five-membered rings, benzene rings, seven-membered rings, and thiophene rings are all non-aromatic or aromatic cyclic structures. After fusion with fluoroboron dipyrrole, the overall molecule remains predominantly aromatic, making it impossible to further narrow the molecular gap by introducing local anti-aromatic properties. This limits the space for regulating photophysical properties and makes it difficult to achieve a breakthrough improvement in optical performance. Existing fused derivatives exhibit weak cyclic voltammetric behavior, making it difficult to form stable anionic radicals, cationic radicals, and dications, and lacking reversible redox peaks. These performance limitations prevent the materials from being suitable for applications requiring repeated redox cycles, such as photothermal therapy and electrochemical energy storage devices. Current fusion methods can only extend planar or simple conjugated structures, failing to construct double-helical chiral configurations. The lack of chiral structure diminishes the materials' application potential in asymmetric photocatalysis, chiral sensing, and chiral drug delivery.

[0005] There is an urgent need in this field for an innovative synthetic strategy to achieve the precise construction of an eight-membered ring fused fluoroboron dipyrrole structure, breaking through the bottlenecks of existing technologies in terms of absorption wavelength, molecular structure characteristics and synthetic efficiency, so as to obtain novel compounds with strong absorption in the near-infrared II region, local anti-aromaticity, double helix chiral configuration and reversible multi-electron redox properties, providing a key material basis for applications such as near-infrared photodetectors and photothermal diagnosis and treatment. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides an eight-membered ring fused fluoroboron dipyrrole compound and its preparation method. The eight-membered ring fused fluoroboron dipyrrole compound exhibits excellent stability, strong near-infrared II absorption, localized anti-aromatic properties, double helix chirality, and reversible redox properties.

[0007] The specific technical solution of this invention is as follows: In a first aspect, the present invention provides an eight-membered ring-fused fluoroboron dipyrrole compound having a structure as shown in Formula I:

[0008] Secondly, the present invention provides a method for preparing the above-mentioned eight-membered ring fused fluoroboron dipyrrole compound, comprising the following steps: S1, 2,7-dibromoanthracene-9-carboxaldehyde and 3,5-di-tert-butylphenylboronic acid were coupled via a palladium-catalyzed Suzuki reaction to give 2-bromo-7-(3,5-di-tert-butylphenyl)anthracene-9-carboxaldehyde; S2, 1-Boc-pyrrole-2-boronic acid and 3,5-di-tert-butylbromobenzene were coupled via a palladium-catalyzed Suzuki reaction to give 2-(3,5-di-tert-butylphenyl)-1H-pyrrole. S3. The 2-bromo-7-(3,5-di-tert-butylphenyl)anthracene-9-carboxaldehyde described in step S1 undergoes a condensation reaction with the 2-(3,5-di-tert-butylphenyl)-1H-pyrrole described in step S2, and then undergoes an oxidation and fluorinated boron cyclization reaction to construct a fluoroboron dipyrrole unit, yielding the reaction intermediate compound BA. S4. The reaction intermediate compound BA described in step S3 undergoes an intermolecular Yamamoto coupling reaction under nickel catalysis to obtain the reaction precursor compound BBA. S5. Under the action of an oxidant, the precursor compound BBA described in step S4 undergoes an intramolecular oxidative dehydrogenation cyclization reaction to obtain the eight-membered ring fused fluoroboron dipyrrole compound.

[0009] The positive and progressive effects of this invention are as follows: This invention provides an eight-membered ring fused fluoroboron dipyrrole compound and its preparation method. The core structure of this eight-membered ring fused fluoroboron dipyrrole compound is a fused skeleton of a double BODIPY unit-antiaromatic eight-membered ring-anthracite ring, with 3,5-di-tert-butylphenyl modified on the periphery. It possesses excellent stability, strong absorption in the near-infrared II region, local antiaromaticity, double helix chirality, and reversible redox properties, and is expected to expand its application fields to near-infrared photodetectors, photothermal diagnostics, etc. The preparation method uses 2,7-dibromoanthracene-9-carboxaldehyde as a precursor, introduces 3,5-di-tert-butylphenyl at position 2 via a Suzuki coupling reaction, constructs fluoroboron dipyrrole at position 9 via condensation, undergoes a Yamamoto coupling reaction at position 7 via palladium catalysis, and synthesizes the eight-membered ring fused fluoroboron dipyrrole compound via an intramolecular oxidative dehydrogenation cyclization reaction initiated by ferric chloride. This preparation method not only has simple process conditions, but also enables the construction of a fully fused framework and the insertion of eight-membered ring units in one step, which has the advantages of high efficiency and scalability. At the same time, the reaction site is precisely controllable, and the obtained product has high structural purity. Attached Figure Description

[0010] Figure 1 The image shows the 1H NMR spectrum of the eight-membered ring fused fluoroboron dipyrrole compound prepared in Example 1.

[0011] Figure 2 This is the single-crystal structure spectrum of the eight-membered ring fused fluoroboron dipyrrole compound prepared in Example 1.

[0012] Figure 3 The image shows the UV-Vis-NIR absorption spectrum of the eight-membered ring fused fluoroboron dipyrrole compound prepared in Example 1.

[0013] Figure 4 The image shows the cyclic voltammetry of the eight-membered ring fused fluoroboron dipyrrole compound prepared in Example 1 in dichloromethane solvent.

[0014] Figure 5 This is an anisotropic magnetic induction current density diagram of the eight-membered ring fused fluoroboron dipyrrole compound prepared in Example 1. Detailed Implementation

[0015] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described in detail below. It should be noted that the following embodiments are only used to illustrate the implementation methods and typical parameters of the present invention, and are not intended to limit the parameter range described in the present invention. Reasonable variations derived therefrom are still within the protection scope of the present invention.

[0016] It should be noted that the endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0017] Unless otherwise defined, all terms, symbols, and other scientific terms used herein are intended to have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. In some instances, terms having a conventional meaning are defined herein for clarification or ease of reference, and such definitions should not be construed as indicating a significant difference from conventional understanding in the art. The technical methods described or referenced herein are generally well understood by those skilled in the art and employed by conventional methods. Unless otherwise stated, the use of commercially available kits, reagents, and instruments shall be performed according to the manufacturer's instructions and parameters.

[0018] The specific technical solution of this invention is as follows: In a first aspect, the present invention provides an eight-membered ring-fused fluoroboron dipyrrole compound having a structure as shown in Formula II:

[0019] The eight-membered ring fused fluoroboron dipyrrole compound provided by this invention has a core structure of a fused skeleton of a double BODIPY unit-antiaromatic eight-membered ring-anthracite ring, with 3,5-di-tert-butylphenyl (Ar) modified on the periphery. Through structural strategies such as conjugation system regulation, spatial conformation design, steric hindrance modification of substituents, and coordination bond stabilization, it synergistically achieves excellent stability, strong near-infrared II absorption, local antiaromaticity, double helix chirality, and reversible redox properties. The core skeleton is dominated by an aromatic conjugated system, and the local antiaromaticity is masked by strong conjugation, resulting in thermodynamic stability. The high bond energy of the BF2 coordination bond of the BODIPY unit contributes to excellent chemical stability. The steric hindrance of the 3,5-di-tert-butylphenyl unit inhibits intermolecular π-π aggregation, improving solution and processing stability. The rigid fused skeleton reduces conformational inversion, resulting in outstanding photothermal stability. The two BODIPY units are fused with an anthracene ring via an antiaromatic eight-membered ring, forming a transmolecular, continuous, large π-conjugated framework. The π electrons are highly delocalized between the BODIPY-eight-membered ring and the anthracene ring, significantly reducing the HOMO-LUMO band gap. This allows π→π* and charge transfer transitions to fall into the near-infrared II region, exhibiting a broad and strong absorption band. The fusion sites of the eight-membered ring with the BODIPY and anthracene rings are sp... 2The hybrid carbon atoms and the bond lengths and angles of the fused bonds cause the eight-membered ring to tend towards planarity, thus forming localized antiaromatic regions. Two BODIPY units are fused with anthracene rings through the eight-membered ring. The fusion angle of the eight-membered ring and the rigidity of the anthracene ring result in a non-planar double-helix twisted conformation of the molecular skeleton. The molecule lacks a center of symmetry, a plane of symmetry, and a rotation axis, possessing inherent chirality. The double BODIPY-eight-membered ring-anthracene ring form a rigid fused skeleton, which fixes the double-helix chirality, making the chiral characteristics stable and persistent. The large steric hindrance of the 3,5-di-tert-butylphenyl group further restricts the conformational inversion of the molecule, locking the helical conformation. Containing two symmetrical BODIPY units, each with an independent redox active site, the stepwise single-electron reduction of the two BODIPY units and the stepwise single-electron oxidation of the fused-ring conjugated system achieve a multi-step, reversible redox process.

[0020] In one possible embodiment, the eight-membered ring fused fluoroboron dipyrrole compound is synthesized as follows: using 2,7-dibromoanthracene-9-carboxaldehyde as a precursor, 3,5-di-tert-butylbenzene is introduced at position 2 via a Suzuki coupling reaction, fluoroboron dipyrrole is constructed at position 9 via condensation, a Yamamoto coupling reaction is carried out at position 7 via palladium catalysis, and an intramolecular oxidative dehydrogenation cyclization reaction initiated by ferric chloride is performed. The introduction of 3,5-di-tert-butylbenzene at position 2 of 2,7-dibromoanthracene-9-carboxaldehyde introduces a sterically hindered aryl group at one end of the anthracene skeleton, disrupting the symmetry of the molecule and laying the foundation for subsequent construction of complex topological structures such as double helices. A fluoroboron dipyrrole unit was constructed at position 9 of 2,7-dibromoanthracene-9-carboxaldehyde. Fluoroboron dipyrrole is a classic luminescent group with high fluorescence quantum yield and high stability. Fusing it to the anthracene backbone gives the entire molecule strong near-infrared absorption and emission. Simultaneously, the introduction of a BF coordination bond forms an extremely stable six-membered chelate ring, greatly enhancing the molecule's photochemical and thermal stability. Utilizing the bromine atom at position 7 of 2,7-dibromoanthracene-9-carboxaldehyde, intermolecular Yamamoto coupling occurs via palladium catalysis. The two modified anthracene-BODIPY units are directly connected by a C-C bond, forming a doubled, highly extended conjugated backbone, significantly reducing the HOMO-LUMO band gap and achieving strong absorption in the near-infrared II (NIR-II) region. Intramolecular oxidative dehydrogenation cyclization removes two hydrogen atoms, forming a new C-C bond between the two BODIPY units, resulting in an eight-membered ring. Eight-membered rings typically possess 4nπ electron characteristics, introducing local anti-aromaticity. This high-energy, unstable electronic structure can significantly modulate the molecule's photoelectric properties. To alleviate ring tension and spatial conflict, the entire large conjugated system will be twisted, forcing the two BODIPY-anthracene units to be arranged in a helical manner, thereby generating the inherent double helical chirality.

[0021] Secondly, the present invention provides a method for preparing the above-mentioned eight-membered ring fused fluoroboron dipyrrole compound, comprising the following steps: S1, 2,7-dibromoanthracene-9-carboxaldehyde and 3,5-di-tert-butylphenylboronic acid were coupled via a palladium-catalyzed Suzuki reaction to give 2-bromo-7-(3,5-di-tert-butylphenyl)anthracene-9-carboxaldehyde; In step S1, the palladium-catalyzed Suzuki coupling is highly specific to the aryl bromide at the 2-position of 2,7-dibromoanthracene-9-carbaldehyde, introducing 3,5-di-tert-butylbenzene only at the 2-position, while the aryl bromide at the 7-position is completely preserved, thus precisely reserving a reaction site for subsequent Yamamoto coupling.

[0022] S2, 1-Boc-pyrrole-2-boronic acid and 3,5-di-tert-butylbromobenzene were coupled via a palladium-catalyzed Suzuki reaction to give 2-(3,5-di-tert-butylphenyl)-1H-pyrrole. In step S2, 1-Boc-pyrrole-2-boronic acid is used as a raw material, and a palladium-catalyzed Suzuki coupling reaction is used to specifically introduce 3,5-di-tert-butylphenyl at the 2-position of 1-Boc-pyrrole-2-boronic acid, with extremely high site selectivity.

[0023] S3. The 2-bromo-7-(3,5-di-tert-butylphenyl)anthracene-9-carboxaldehyde described in step S1 undergoes a condensation reaction with the 2-(3,5-di-tert-butylphenyl)-1H-pyrrole described in step S2, and then undergoes an oxidation and fluorinated boron cyclization reaction to construct a fluoroboron dipyrrole unit, yielding the reaction intermediate compound BA. In step S3, a one-pot process of "condensation + oxidation + fluorinated boron cyclization" is used to precisely combine 2-bromo-7-(3,5-di-tert-butylphenyl)anthracene-9-carboxaldehyde (anthracene ring skeleton) obtained in step S1 and 2-(3,5-di-tert-butylphenyl)-1H-pyrrole (pyrrole skeleton) obtained in step S2, thereby constructing an anthracene ring-linked fluorinated boron dipyrrole (BODIPY) core functional unit. This transforms the originally separated anthracene ring and pyrrole structural units into an anthracene ring-containing reaction intermediate compound BA; at the same time, it precisely reserves active sites for subsequent coupling and cyclization reactions.

[0024] S4. The reaction intermediate compound BA described in step S3 undergoes an intermolecular Yamamoto coupling reaction under nickel catalysis to obtain the reaction precursor compound BBA. In step S4, two reaction intermediate compounds BA are integrated into a symmetrical bis-BODIPY-anthracycline reaction precursor BBA through nickel-catalyzed Yamamoto intermolecular coupling. This provides a precise structural basis and a spatially matched cyclization precursor for subsequent intramolecular oxidative dehydrogenation cyclization, while extending the conjugated system, retaining the advantages of functional substituents, and laying the foundation for electrochemical performance sites.

[0025] S5. Under the action of an oxidant, the precursor compound BBA described in step S4 undergoes an intramolecular oxidative dehydrogenation cyclization reaction to obtain the eight-membered ring fused fluoroboron dipyrrole compound.

[0026] In step S5, an eight-membered ring fused core framework is precisely constructed based on the symmetrical double BODIPY-anthracene ring reaction precursor BBA prepared in step S4 through an intramolecular oxidative dehydrogenation cyclization reaction. At the same time, the ultimate extension of the conjugated system and the shaping and optimization of the core performance are completed.

[0027] The method for preparing eight-membered ring fused fluoroboron dipyrrole compounds provided by this invention employs a five-step synthetic route involving double Suzuki coupling, BODIPY construction, Yamamoto coupling, and intramolecular oxidative dehydrogenation cyclization. This method precisely synthesizes eight-membered ring fused fluoroboron dipyrrole compounds that possess excellent stability, strong near-infrared II absorption, localized anti-aromatic properties, double-helix chirality, and reversible redox properties. The preparation method for eight-membered ring fused fluoroboron dipyrrole compounds not only features simple process conditions but also achieves the construction of a fully fused framework and the insertion of eight-membered ring units in one step, offering advantages such as high efficiency and scalability. Furthermore, the reaction sites are precisely controllable, resulting in products with high structural purity.

[0028] In one possible implementation, step S1 is as follows: In a reaction flask, 2,7-dibromoanthracene-9-carboxaldehyde, 3,5-di-tert-butylphenylboronic acid, a base, an organic solvent, and water are added and mixed thoroughly to obtain a mixture. After bubbling the mixture with nitrogen, a palladium complex containing a phosphine ligand is added, and a Suzuki coupling reaction is carried out at 80-100 °C. The resulting mixture is then subjected to extraction, vacuum distillation, and column chromatography to obtain 2-bromo-7-(3,5-di-tert-butylphenyl)anthracene-9-carboxaldehyde. By limiting the specific process parameters and operating procedures of step S1, nitrogen bubbling eliminates air interference, and the reaction temperature is limited, ensuring the regioselectivity of the Suzuki coupling reaction and reducing side reactions. The post-treatment methods of extraction, vacuum distillation, and column chromatography effectively purify the intermediate 2-bromo-7-(3,5-di-tert-butylphenyl)anthracene-9-carboxaldehyde, improving its purity.

[0029] Furthermore, the base is sodium carbonate, potassium carbonate, cesium carbonate, or potassium phosphate. Sodium carbonate, potassium carbonate, cesium carbonate, or potassium phosphate can provide the alkaline reaction environment required for Suzuki coupling, promote the deprotonation activation of 3,5-di-tert-butylphenylboronic acid, and accelerate the coupling reaction; moreover, the alkalinity is mild, does not destroy the anthracene ring skeleton and aldehyde activity of 2,7-dibromoanthracene-9-carboxaldehyde, and does not trigger abnormal substitution of aryl bromides, thus inhibiting acidic side reactions and ensuring reaction selectivity.

[0030] Furthermore, the palladium complex containing the phosphine ligand is one of 1,1′-bis(diphenylphosphine)ferrocene palladium dichloride, tetra(triphenylphosphine)palladium, and 1,3-bis(diphenylphosphine)propane palladium dichloride. The aforementioned palladium complex containing the phosphine ligand, as a highly efficient catalyst for Suzuki coupling, specifically activates the aryl bromide active site at position 2, significantly improving reaction efficiency and regioselectivity, and reducing byproducts from simultaneous coupling at positions 2 and 7; it exhibits high catalytic activity, and the complex structure between the ligand and palladium is stable.

[0031] Furthermore, the organic solvent is at least one selected from 1,4-dioxane, tetrahydrofuran, toluene, and N,N-dimethylformamide. These organic solvents can efficiently dissolve reaction substrates such as 2,7-dibromoanthracene-9-carboxaldehyde and 3,5-di-tert-butylphenylboronic acid, providing a homogeneous reaction environment and ensuring a uniform and stable reaction. They also exhibit moderate miscibility with water, neither affecting the dissolution of alkali in the aqueous phase nor hindering the extraction and separation of the organic phase after the reaction, thus simplifying the post-processing procedures.

[0032] Further, the molar ratio of 2,7-dibromoanthracene-9-carboxaldehyde to 3,5-di-tert-butylphenylboronic acid is 1:(0.8~1.2); the molar ratio of the base to 2,7-dibromoanthracene-9-carboxaldehyde is (1.5~3):1; the volume-to-mass ratio of the organic solvent to 2,7-dibromoanthracene-9-carboxaldehyde is 20 mL / g~100 mL / g; the volume ratio of water to the organic solvent is 1:(3~10); and the amount of the palladium complex containing the phosphine ligand is 0.5% to 5% of the molar amount of 2,7-dibromoanthracene-9-carboxaldehyde. Limiting the dosage range of 2,7-dibromoanthracene-9-carboxaldehyde, 3,5-di-tert-butylphenylboronic acid, base, organic solvent, and palladium complex containing phosphine ligands ensures complete reaction between 2,7-dibromoanthracene-9-carboxaldehyde and 3,5-di-tert-butylphenylboronic acid; controlling reagent dosage reduces synthesis costs while ensuring the stability of the reaction system, improving the yield and purity of intermediates, and ensuring process reproducibility.

[0033] In one possible implementation, step S2 is as follows: In a reaction flask, 1-Boc-pyrrole-2-boric acid, 3,5-di-tert-butylbromobenzene, a base, a palladium complex containing a phosphine ligand, and a mixed solvent of toluene and methanol are added and mixed thoroughly to obtain a mixture. After bubbling the mixture in the reaction flask with nitrogen, the palladium complex containing a phosphine ligand is added, and a Suzuki coupling reaction is carried out at 100-130°C. The resulting mixture is then extracted, distilled under reduced pressure, and subjected to column chromatography to obtain 2-(3,5-di-tert-butylphenyl)-1H-pyrrole. By defining the specific process parameters and operating flow of step S2, the 3,5-di-tert-butylphenyl substitution at the 2-position of pyrrole is precisely achieved through a three-step ordered reaction involving Grignard addition, Friedel-Crafts alkylation, and oxidative dehydrogenation, ensuring the specificity of the substituent site. The reactions are smoothly connected, and the post-processing is simple, effectively purifying the pyrrole to obtain high-purity 2-(3,5-di-tert-butylphenyl)-1H-pyrrole.

[0034] Further, the base is sodium carbonate, potassium carbonate, cesium carbonate, or potassium phosphate. This base is suitable for the Suzuki coupling reaction in step S2, providing a mild alkaline environment to promote the deprotonation activation of 1-Boc-pyrrole-2-boronic acid, accelerating the coupling reaction; it does not damage the pyrrole ring and Boc protecting group structure, suppresses side reactions, ensures the specificity of pyrrole 2-position substitution, and improves the purity of the intermediate.

[0035] Further, the palladium complex containing the phosphine ligand is one of 1,1′-bis(diphenylphosphine)ferrocene palladium dichloride, tetra(triphenylphosphine)palladium, and 1,3-bis(diphenylphosphine)propane palladium dichloride. The aforementioned palladium complex containing the phosphine ligand serves as a highly efficient catalyst for the Suzuki coupling in step S2, specifically activating the aryl bromide site of 3,5-di-tert-butylbromobenzene, promoting the coupling reaction with 1-Boc-pyrrole-2-boronic acid, and reducing substitution side reactions at other sites of the pyrrole ring. Furthermore, it exhibits high catalytic efficiency, requires a small amount, reduces catalytic costs, and ensures a stable and controllable reaction.

[0036] Further, the molar ratio of 1-Boc-pyrrole-2-boric acid to 3,5-di-tert-butylbromobenzene is 1:(0.5~1.2), the molar ratio of the base to 3,5-di-tert-butylbromobenzene is (2~4):1, the amount of the palladium complex containing the phosphine ligand is 0.5%~5% of the molar amount of 3,5-di-tert-butylbromobenzene, and the volume ratio of toluene to methanol is (5~20):1. Limiting the proportions of 1-Boc-pyrrole-2-boric acid, 3,5-di-tert-butylbromobenzene, the base, and the palladium complex containing the phosphine ligand ensures sufficient reaction between 1-Boc-pyrrole-2-boric acid and 3,5-di-tert-butylbromobenzene, avoiding waste of raw materials and generation of byproducts; controlling the volume ratio of toluene to methanol optimizes the solubility of the reaction system, facilitates post-processing separation, and improves the yield and purity of 2-(3,5-di-tert-butylphenyl)-1H-pyrrole.

[0037] In one possible implementation, step S3 is as follows: 2-bromo-7-(3,5-di-tert-butylphenyl)anthracene-9-carboxaldehyde and an organic solvent are added to a reaction flask. After bubbling with nitrogen, 2-(3,5-di-tert-butylphenyl)-1H-pyrrole and an acidic catalyst are added to carry out a condensation reaction to obtain a dipyrrolemethane intermediate. The dipyrrolemethane intermediate is oxidized under the action of an oxidant, and then undergoes a fluorination-boronization cyclization reaction with triethylamine and a boron trifluoride complex. The resulting mixture is subjected to vacuum distillation and column chromatography to obtain the reaction intermediate compound BA with a fluorinated boron dipyrrole structure. The specific process flow of step S3 is defined, and the orderly connection of "condensation-oxidation-fluorinated borosilicate cyclization" ensures the site-specific condensation of the aldehyde group at the 9-position of the anthracene ring with pyrrole, accurately constructing the BODIPY core unit of the anthracene ring connection; nitrogen bubbling eliminates air interference and avoids oxidation side reactions, the post-processing method is simple, and high-purity intermediate BA can be effectively purified to obtain the intermediate, while the active site of the aryl bromide at the 7-position is completely preserved, which is suitable for the Yamamoto coupling reaction in the subsequent S4 and improves the overall synthesis efficiency.

[0038] Furthermore, the acidic catalyst is at least one selected from trifluoroacetic acid, p-toluenesulfonic acid, boron trifluoride ether, and ferric chloride. The aforementioned acidic catalyst can efficiently catalyze the condensation reaction in step S3, promoting the dehydration condensation of 2-bromo-7-(3,5-di-tert-butylphenyl)anthracene-9-carboxaldehyde with pyrrole, accelerating the formation of the dipyrrolemethane intermediate; and its moderate acidity does not damage the anthracene ring or pyrrole ring structure, nor does it affect subsequent oxidation and fluorination reactions, thus improving the efficiency and selectivity of the condensation reaction.

[0039] Furthermore, the oxidant is selected from at least one of 2,3-dichloro-5,6-dicyano-1,4-benzoquinone, chloroquinone, and tetrachlorobenzoquinone. The aforementioned oxidant can mildly oxidize and dehydrogenate the dipyrrolemethane intermediate, converting the saturated methylene structure into an unsaturated conjugated structure, laying the foundation for subsequent fluoroboryl cyclization; and it exhibits high oxidation selectivity, acting only on the methylene sites of dipyrrolemethane without excessively oxidizing the anthracene ring, pyrrole ring, and substituents, thus ensuring the structural integrity of the intermediate.

[0040] Furthermore, the boron trifluoride complex is at least one selected from boron trifluoride diethyl ether complex, boron trifluoride methanol complex, and boron trifluoride tetrahydrofuran complex. This boron trifluoride complex serves as a specialized reagent for fluorinated boron cyclization, reacting precisely with the oxidized dipyrrole intermediate to construct a complete BODIPY core BF2 coordination structure. The complex exhibits good stability and high reaction selectivity, ensuring the structural integrity and photophysical performance potential of the BODIPY unit.

[0041] Furthermore, the reaction temperature of the condensation reaction is 10~40 °C.

[0042] Furthermore, the oxidation reaction is carried out at a temperature of 10-40 °C for 0.5-2 h.

[0043] Furthermore, the reaction temperature of the fluorinated boron cyclization reaction is 10~40 °C, and the reaction time is 2~6 h.

[0044] Limiting the temperature of condensation, oxidation, and fluorinated cyclization reactions can control the reaction rate, avoiding incomplete reactions caused by low temperatures and side reactions caused by high temperatures; reactions at room temperature do not require high-temperature equipment, reducing process costs, ensuring stable and controllable reactions, and helping to improve the purity and yield of intermediate BA.

[0045] Further, the molar ratio of 2-bromo-7-(3,5-di-tert-butylphenyl)anthracene-9-carboxaldehyde to 2-(3,5-di-tert-butylphenyl)-1H-pyrrole is 1:(2~2.5); the amount of acidic catalyst is 10%~50% of the molar amount of 2-bromo-7-(3,5-di-tert-butylphenyl)anthracene-9-carboxaldehyde; the molar ratio of the oxidant to 2-bromo-7-(3,5-di-tert-butylphenyl)anthracene-9-carboxaldehyde is... The ratio is (1~2):1; the molar ratio of triethylamine to 2-bromo-7-(3,5-di-tert-butylphenyl)anthracene-9-carboxaldehyde is (80~100):1; the molar ratio of boron trifluoride complex to 2-bromo-7-(3,5-di-tert-butylphenyl)anthracene-9-carboxaldehyde is (100~150):1; the mass-volume ratio of organic solvent to 2-bromo-7-(3,5-di-tert-butylphenyl)anthracene-9-carboxaldehyde is 200 mL / g~600 mL / g. Limiting the dosage range of 2-bromo-7-(3,5-di-tert-butylphenyl)anthracene-9-carboxaldehyde, 2-(3,5-di-tert-butylphenyl)-1H-pyrrole, catalyst, oxidant, and boron trifluoride complex ensures the full and orderly progress of the three-step reaction of condensation, oxidation, and fluorinated boron cyclization; avoiding side reactions and post-processing difficulties caused by excessive use of a single reagent, controlling reagent dosage, reducing costs, and ensuring the integrity of the BODIPY core structure and the purity of intermediate BA meets the standards. In one possible implementation, step S4 is as follows: In an inert gas atmosphere, a nickel catalyst, a nitrogen-containing ligand, and an olefinic co-ligand dissolved in an amide solvent are added to a reaction flask to carry out a catalyst activation reaction, thereby obtaining a catalytic system; then, the reaction intermediate compound BA from step S3 is dissolved in an aromatic solvent and added dropwise to the catalytic system, and the temperature is raised to carry out an intermolecular Yamamoto coupling reaction; after the reaction is completed, the resulting reaction solution is diluted, washed, concentrated by vacuum distillation, and separated by column chromatography to obtain the reaction precursor compound BBA. The specific process flow for step S4 is defined. The catalyst activation step enhances the catalytic activity of the nickel catalyst, and the inert gas atmosphere eliminates air interference and avoids catalyst oxidation and deactivation. The dropping method and temperature control ensure the regioselectivity of Yamamoto coupling (specifically activating the aryl bromide at position 7) and accurately form the symmetrical bis-BODIPY-anthracene ring precursor BBA. The subsequent dilution, washing, and column chromatography post-processing methods can effectively purify the precursor BBA, ensuring its structural symmetry and purity, and are suitable for the subsequent intramolecular oxidative dehydrogenation cyclization reaction in S5. The process is highly reproducible and easily scalable.

[0046] Furthermore, the nickel catalyst is selected from at least one of bis(1,5-cyclooctadiene)nickel, bis(triphenylphosphine)nickel dichloride, and nickel acetylacetonate. As a dedicated catalyst for Yamamoto coupling, the above-mentioned nickel catalyst efficiently activates the aryl bromide site at position 7 of the intermediate BA, promoting precise intermolecular coupling. It exhibits stable catalytic activity and is not easily deactivated; it is well-suited to the activation process and reaction system, without excessive catalytic side reactions, thus ensuring the structural integrity of the bis-BODIPY precursor BBA.

[0047] Furthermore, the nitrogen-containing ligand is selected from at least one of 2,2'-bipyridine, 1,10-phenanthroline, N,N,N',N'-tetramethylethylenediamine, and tris(2-pyridylmethyl)amine. The above-mentioned nitrogen-containing ligands form stable complexes with the nickel catalyst, significantly improving catalyst activity and selectivity; precisely controlling the coupling reaction sites reduces intermolecular polymerization side reactions, ensuring a stable and controllable coupling reaction, and improving the purity of the precursor BBA.

[0048] Furthermore, the olefinic ligand is selected from at least one of 1,5-cyclooctadiene, 1,4-cyclooctadiene, norbornadiene, and cycloheptadiene. These olefinic ligands can assist in activating the complex structure of the nickel catalyst, further improving catalytic efficiency and shortening the reaction induction period; simultaneously, they regulate the solubility of the catalytic system, prevent catalyst aggregation, ensure a homogeneous reaction environment, and improve the reproducibility of the coupling reaction.

[0049] Furthermore, the amide solvent is selected from at least one of N,N-dimethylacetamide (DMA), N-methylpyrrolidone (NMP), and hexamethylphosphoric triamine (HMPA), and the aromatic solvent is selected from at least one of anhydrous toluene, anhydrous xylene, anhydrous ethylbenzene, and anhydrous chlorobenzene. The aforementioned amide solvents can efficiently dissolve nickel catalysts and ligands, providing a stable and homogeneous environment for catalyst activation without damaging the active structure of the catalyst; the aforementioned aromatic solvents can efficiently dissolve intermediate BA, without participating in the reaction or damaging the conjugated framework, facilitating subsequent dilution, washing, and separation.

[0050] Furthermore, the catalyst activation reaction temperature is 50-60 °C, and the reaction time is 20-40 min. An activation temperature of 50-60 °C ensures sufficient catalyst activation and improves catalytic efficiency; an activation time of 20-40 min ensures complete catalyst activation without excessive time, thus avoiding energy waste and side reactions.

[0051] Furthermore, the intermolecular Yamamoto coupling reaction is carried out at a temperature of 75-85 °C for a reaction time of 3-5 h. The temperature of 75-85 °C controls the coupling reaction rate, ensuring precise intermolecular coupling and guaranteeing the purity and yield of the precursor BBA; the coupling time of 3-5 h ensures complete coupling of the reaction intermediate BA.

[0052] Furthermore, the solvent used to dilute the reaction solution is ethyl acetate, and the reagents used to wash the organic phase are saturated ammonium chloride solution and saturated saline solution. Ethyl acetate serves as a mild dilution solution, which does not damage the structure of the precursor BBA, facilitating subsequent layer separation; saturated ammonium chloride solution and saturated saline solution can efficiently remove impurities such as catalysts and ligands from the reaction solution without dissolving the target product, simplifying post-processing and improving the purity of the precursor BBA.

[0053] Further, the molar ratio of the nickel catalyst to compound BA is (1.2~2):1; the molar ratio of the nitrogen-containing ligand to compound BA is (1.2~2):1; the molar ratio of the olefinic co-ligand to compound BA is (1~2):1; the volume ratio of the amide solvent to the molar amount of compound BA is 100 mL / mmol~500 mL / mmol; and the volume ratio of the aromatic solvent to the molar amount of compound BA is 100 mL / mmol~500 mL / mmol. Limiting the proportions of the nickel catalyst, nitrogen-containing ligand, olefinic co-ligand, amide solvent, and aromatic solvent to intermediate BA ensures sufficient catalyst activation and complete coupling of BA; avoids cost waste and post-processing difficulties caused by excessive reagents; ensures the stability of the reaction system; improves the yield and purity of the precursor BBA; and ensures process reproducibility.

[0054] In one possible implementation, step S5 is as follows: Under an inert gas atmosphere, the precursor compound BBA is dissolved in a haloalkanes solvent, and an iron(III) salt oxidant dissolved in a nitroalkanes solvent is added dropwise at a low temperature of -5 to 5 °C. The reaction is first carried out at a low temperature of -5 to 5 °C, and then the temperature is raised to 10 to 40 °C for intramolecular oxidative dehydrogenation cyclization. After the reaction, the mixture is quenched, extracted, concentrated by vacuum distillation, and separated by column chromatography to obtain the compound OBNG. The specific process flow of step S5 is limited. The inert gas atmosphere avoids oxidation interference, and the addition of the oxidant at a low temperature of -5 to 5 °C can reduce excessive oxidation side reactions. Stepwise temperature control (initial reaction at a low temperature of -5 to 5 °C, cyclization at room temperature of 10 to 40 °C) ensures the regioselectivity of intramolecular oxidative dehydrogenation cyclization and accurately constructs an eight-membered ring fused framework. The post-processing is simple and can effectively purify the target compound OBNG to a high purity, ensuring the structural integrity and core performance of the product, and is compatible with the overall mild and efficient synthesis logic.

[0055] Furthermore, the halocarbon solvent is at least one selected from dichloromethane, chloroform, and 1,2-dichloroethane. These halocarbon solvents can efficiently dissolve the precursor BBA, provide a homogeneous reaction environment, and are suitable for reaction temperatures ranging from low to room temperature; they do not participate in cyclization reactions, do not disrupt the conjugated skeleton and BF2 coordination structure, and facilitate subsequent extraction and separation.

[0056] Furthermore, the nitroalkane solvent is at least one selected from nitromethane, 1-nitropropane, and 1-nitropropane. The aforementioned nitroalkane solvent can efficiently dissolve iron(III) salt-based oxidants, ensuring uniform dispersion of the oxidants, achieving slow release of oxidizing properties at low temperatures, and reducing excessive oxidation side reactions; it also exhibits good compatibility with haloalkanes and does not affect the selectivity of the cyclization reaction.

[0057] Furthermore, the iron(III) salt oxidant is selected from at least one of ferric tribromide, ferric sulfate, ferric chloride hexahydrate, and ferric nitrate. As a mild single-electron oxidant, the aforementioned iron(III) salt oxidant specifically initiates the intramolecular oxidative dehydrogenation cyclization of the precursor BBA without initiating intermolecular polymerization; it exhibits high oxidative selectivity, acting only on the active sites required for cyclization without damaging substituents and the core skeleton, thus ensuring the structural integrity of the target compound.

[0058] Furthermore, the quenching reagent used is a saturated sodium bicarbonate solution, and the extraction solvent used is dichloromethane. Saturated sodium bicarbonate solution can gently quench excess oxidant, neutralize the reaction system, prevent residual oxidant from damaging the target product, and avoid introducing impurities; dichloromethane can efficiently extract the target compound OBNG, does not dissolve aqueous impurities, produces clear layering, simplifies post-processing, and improves product purity.

[0059] Further, the molar ratio of the iron(III) salt oxidant to the compound BBA is (30~80):1; the volume molar ratio of the haloalkane solvent to the compound BBA is 200 mL / mmol~1000 mL / mmol; and the volume molar ratio of the nitroalkane solvent to the compound BBA is 50 mL / mmol~500 mL / mmol. Limiting the proportions of the iron(III) salt oxidant, haloalkane solvent, and precursor BBA ensures sufficient oxidant to initiate the cyclization reaction and complete dissolution and reaction of BBA; controlling the solvent dosage optimizes reaction efficiency, ensuring the target compound OBNG achieves the required purity and stable yield.

[0060] In one possible implementation, the 2,7-dibromoanthracene-9-carboxaldehyde described in step S1 is obtained by the following steps: P1, 5-bromo-2-methylbenzaldehyde and 1-bromo-4-iodobenzene were coupled via a palladium-catalyzed carbon-hydrogen bond activation reaction to give the precursor 5-bromo-2-(4-bromobenzyl)benzaldehyde; P2. The 5-bromo-2-(4-bromobenzyl)benzaldehyde described in step P1 undergoes Grignard reaction, Friedel-Crafts alkylation reaction and oxidative dehydrogenation reaction in sequence under the action of methyl magnesium bromide to give 2,7-dibromo-9-methylanthracene. P3. The 2,7-dibromo-9-methylanthracene described in step P2 is subjected to bromination, transesterification, alkaline hydrolysis, and Swern oxidation to obtain 2,7-dibromoanthracene-9-carboxaldehyde.

[0061] The preparation process of the key precursor 2,7-dibromoanthracene-9-carboxaldehyde in step S1 was clearly defined. Through a three-step ordered reaction from P1 to P3 (C-H bond activation coupling → Grignard + Friedel-Crafts + oxidative dehydrogenation → bromination + transesterification + hydrolysis + Swern oxidation), the core structure of 2,7-dibromoanthracene-9-carboxaldehyde was precisely constructed, ensuring the activity and site integrity of the aryl bromine at 2,7 and the aldehyde group at 9. The reaction steps were smoothly connected, and the precursor could be effectively purified to obtain high purity, providing qualified raw materials for the Suzuki coupling in step S1.

[0062] Further, the specific process of step P1 is as follows: 5-bromo-2-methylbenzaldehyde and 1-bromo-4-iodobenzene are reacted in a mixed solvent system of palladium(II) salt catalyst, silver salt promoter, nitrogen-containing ligand, and carboxylic acid solvent-water, and heated to 85-95 °C after stirring to carry out a carbon-hydrogen bond activation coupling reaction. After the reaction, the resulting reaction solution is filtered, concentrated under reduced pressure, and separated by column chromatography to obtain the 5-bromo-2-(4-bromobenzyl)benzaldehyde. By standardizing the specific process flow of P1, limiting the reaction temperature to 85-95 °C and the post-treatment method, the regioselectivity of carbon-hydrogen bond activation coupling is ensured, and 5-bromo-2-(4-bromobenzyl)benzaldehyde is accurately prepared. The synergistic effect of the reagents improves the coupling efficiency and the purity of the intermediate, providing qualified raw materials for the subsequent P2 reaction.

[0063] Furthermore, the palladium(II) salt catalyst is selected from at least one of palladium acetate, palladium trifluoroacetate, and palladium chloride. The aforementioned palladium(II) salt catalyst can efficiently catalyze carbon-hydrogen bond activation coupling reactions, specifically activating reaction sites and promoting the precise coupling of 5-bromo-2-methylbenzaldehyde and 1-bromo-4-iodobenzene; it exhibits high catalytic activity, requires low dosage, reduces catalytic costs, and ensures a stable and controllable reaction.

[0064] Furthermore, the silver salt promoter is selected from at least one of silver trifluoroacetate, silver acetate, and silver carbonate. The aforementioned silver salt promoter can assist in activating the palladium catalyst, promote C-H bond activation, and accelerate the coupling reaction; simultaneously, it suppresses side reactions such as debromination, thereby improving the selectivity of the coupling reaction and the purity of the intermediate.

[0065] Furthermore, the nitrogen-containing ligand is at least one of glycine, N-acetylglycine, and proline. These nitrogen-containing ligands can form stable complexes with the palladium catalyst, further enhancing catalytic activity and regioselectivity, preventing catalyst aggregation or deactivation, and ensuring the reproducibility of the coupling reaction.

[0066] Furthermore, the carboxylic acid solvent is at least one selected from acetic acid, trifluoroacetic acid, and propionic acid. The aforementioned carboxylic acid solvent can provide the acidic environment required for C-H bond activation, promoting the reaction; simultaneously, it dissolves the reaction substrate and catalyst, providing a homogeneous reaction environment without damaging the substrate structure, facilitating subsequent post-processing.

[0067] Furthermore, the molar ratio of 1-bromo-4-iodobenzene to 5-bromo-2-methylbenzaldehyde is (1~2):1; the molar ratio of the palladium(II) salt catalyst to 5-bromo-2-methylbenzaldehyde is (0.05~0.15):1; the molar ratio of the silver salt auxiliary to 5-bromo-2-methylbenzaldehyde is (1~2):1; the molar ratio of the nitrogen-containing ligand to 5-bromo-2-methylbenzaldehyde is (0.2~0.5):1; the volume ratio of the carboxylic acid solvent-water mixed solvent system to the molar amount of 5-bromo-2-methylbenzaldehyde is 5 mL / mmol-15 mL / mmol; and the volume ratio of the carboxylic acid solvent to water is (8~10):1. By limiting the proportions of each reagent in step P1, the coupling of 1-bromo-4-iodobenzene and 5-bromo-2-methylbenzaldehyde is ensured. The amounts of palladium(II) salt catalyst, silver salt promoter, and nitrogen-containing ligand are controlled to balance catalytic efficiency and cost. The amount and proportion of mixed solvent are limited to ensure the full dissolution of substrate and reagent, providing a stable homogeneous reaction environment, improving the yield and purity of intermediate 5-bromo-2-(4-bromobenzyl)benzaldehyde, and ensuring process repeatability.

[0068] Further, the specific process of step P2 is as follows: 5-bromo-2-(4-bromobenzyl)benzaldehyde is dissolved in an ether solvent, cooled to -5 ℃ to 10 ℃, and Grignard reagent is added to carry out Grignard addition reaction. After the reaction is completed, water is added to quench, extract, and concentrate under reduced pressure to obtain the first crude product; the first crude product is dissolved in a haloalkanes solvent, cooled to -85 ℃ to -70 ℃, and acidic catalyst is added to carry out Friedel-Crafts alkylation reaction. The temperature is then raised to room temperature to continue Friedel-Crafts alkylation reaction. After the reaction is completed, water is added to quench, extract, concentrate under reduced pressure, and wash to obtain the second crude product; the second crude product and an oxidizing agent are dissolved in an aromatic solvent, heated to 95~105 ℃ to carry out oxidative dehydrogenation reaction. After the reaction is completed, the solution is concentrated under reduced pressure and separated by column chromatography to obtain the 2,7-dibromo-9-methylanthracene. By standardizing the specific process flow of P2, and implementing step-by-step temperature control and post-processing methods, the three-step reactions of Grignard addition, Friedel-Crafts alkylation, and oxidative dehydrogenation are ensured to proceed in an orderly manner, accurately preparing 2,7-dibromo-9-methylanthracene. Each step of the reaction has high selectivity and few side reactions, and can effectively purify to obtain high-purity intermediates, which are suitable for subsequent P3 reactions.

[0069] Furthermore, the Grignard reagent is selected from methyl magnesium bromide, methyl magnesium chloride, or methyl magnesium iodide. All of the above Grignard reagents are suitable for P2 addition reactions, and can efficiently undergo addition reactions with the aldehyde group of 5-bromo-2-(4-bromobenzyl)benzaldehyde, exhibiting high selectivity and without damaging the benzene ring or aryl bromide structure.

[0070] Furthermore, the Grignard reagent is first dissolved in an ether solvent before being added, wherein the ether solvent is selected from tetrahydrofuran or diethyl ether, and the concentration of the Grignard reagent is 2.5-3.5 mol / L. Dissolving the Grignard reagent in an ether solvent before addition avoids the violent local reactions and increased side reactions that would result from direct addition of the Grignard reagent, ensuring a stable reaction. Limiting the concentration of the Grignard reagent to 2.5-3.5 mol / L ensures its activity.

[0071] Furthermore, the acidic catalyst is selected from trifluoromethanesulfonic acid, methanesulfonic acid, or a system containing trifluoromethanesulfonic acid anhydride. All of the above acidic catalysts are suitable for P2 Friedel-Crafts alkylation reactions, exhibiting high catalytic activity, efficiently promoting the Friedel-Crafts alkylation reaction, strong reaction selectivity, and no side reactions such as aryl bromide removal or benzene ring isomerization. These catalysts are readily available, easily separated after post-processing, and leave no impurities, ensuring the purity of the second crude product.

[0072] Furthermore, the oxidant is selected from 2,3-dichloro-5,6-dicyano-1,4-benzoquinone, chloroquinone, or tetrachlorobenzoquinone. All of the above oxidants can serve as dedicated oxidants for the P2 oxidative dehydrogenation reaction, achieving a mild and efficient dehydrogenation reaction, converting the saturated structure into an anthracene ring conjugated structure. They exhibit high oxidation selectivity, acting only on the target dehydrogenation site without over-oxidizing the substrate or damaging the aryl bromide structure. All oxidants are stable, readily available, and easily separated after the reaction, ensuring the structural integrity and purity of 2,7-dibromo-9-methylanthracene.

[0073] Furthermore, the aromatic solvent is selected from toluene or xylene. The aforementioned aromatic solvent can efficiently dissolve the second crude product and the oxidant, is suitable for the oxidative dehydrogenation reaction temperature requirement of 95-105 °C, does not participate in the reaction, and does not damage the anthracene ring skeleton and aryl bromide structure; the solvent has a moderate boiling point, facilitating subsequent vacuum concentration and separation, and can be flexibly selected according to process requirements, improving process applicability.

[0074] Furthermore, the haloalkanes solvent is selected from at least one of dichloromethane, chloroform, and 1,2-dichloroethane. These haloalkanes solvents can efficiently dissolve the first crude product, are suitable for the temperature conditions of the Friedel-Crafts alkylation reaction, and provide a stable homogeneous environment for the reaction; they do not participate in the Friedel-Crafts alkylation reaction, do not damage the substrate structure, and exhibit clear separation from the subsequent quenching reagents, facilitating extraction and separation and simplifying the post-processing procedures.

[0075] Furthermore, the volume ratio of the ether solvent to the molar ratio of 5-bromo-2-(4-bromobenzyl)benzaldehyde is 5 mL / mmol to 10 mL / mmol; the molar ratio of the Grignard reagent to 5-bromo-2-(4-bromobenzyl)benzaldehyde is (1.2~2):1; the molar ratio of the acid catalyst to 5-bromo-2-(4-bromobenzyl)benzaldehyde is (1.0~2.0):1; the volume ratio of the haloalkane solvent to the molar ratio of 5-bromo-2-(4-bromobenzyl)benzaldehyde is 5 mL / mmol to 15 mL / mmol; the molar ratio of the oxidant to 5-bromo-2-(4-bromobenzyl)benzaldehyde is (0.8~1.5):1; and the molar ratio of the aromatic solvent to 5-bromo-2-(4-bromobenzyl)benzaldehyde is 5 mL / mmol to 10 mL / mmol. Limiting the proportions of each reagent in step P2 ensures the full progress of the Grignard addition, Friedel-Crafts alkylation, and oxidative dehydrogenation reactions; controlling the amount of various solvents optimizes reaction efficiency and post-processing difficulty, reduces synthesis costs, and ensures stable yield and purity of 2,7-dibromo-9-methylanthracene.

[0076] Further, the specific process of step P3 is as follows: 2,7-dibromo-9-methylanthracene is dissolved in a haloalkane solvent with a brominating reagent and an initiator, and the temperature is raised to 85-95 °C to carry out a bromination reaction. After the reaction, the mixture is concentrated under reduced pressure and separated by column chromatography to obtain 2,7-dibromo-9-(bromomethyl)anthracene; the 2,7-dibromo-9-(bromomethyl)anthracene is dissolved in an amide solvent with a potassium salt reagent and a phase transfer catalyst, and the temperature is raised to 95-105 °C to carry out a transesterification reaction. After the reaction, a quenching reagent is added, followed by extraction, concentration under reduced pressure, and separation by column chromatography to obtain methyl acetate (2,7-dibromoanthracene-9-yl); the methyl acetate (2,7-dibromoanthracene-9-yl) is dissolved in an alcohol solvent with a base reagent, and the temperature is raised to 75-85 °C. An alkaline hydrolysis reaction was carried out at ℃. After the reaction, the mixture was concentrated under reduced pressure, water was added, and the mixture was filtered to obtain (2,7-dibromoanthracene-9-yl)methanol. Oxaloyl chloride was dissolved in a haloalkanes solvent, cooled to -85 ℃ to -70 ℃, and dimethyl sulfoxide was added to react. Then, the (2,7-dibromoanthracene-9-yl)methanol was added to carry out a Swern oxidation reaction. Subsequently, an organic amine reagent was added to continue the reaction. After heating to room temperature, the mixture was concentrated, dissolved, washed, concentrated under reduced pressure, and separated by column chromatography to obtain 2,7-dibromoanthracene-9-carboxaldehyde. By standardizing the specific process flow of P3, the four-step orderly reaction (bromination → transesterification → alkaline hydrolysis → Swern oxidation) accurately achieves the conversion of 2,7-dibromo-9-methylanthracene to 2,7-dibromoanthracene-9-carboxaldehyde, completely preserving the aryl bromine activity at the 2,7-position and the aldehyde function at the 9-position. The reaction conditions of each step are mild, and the post-processing is simple, which can effectively purify and obtain high-purity target precursors.

[0077] Furthermore, the brominating reagent is selected from at least one of N-bromosuccinimide, N-bromoacetamide, and 1,3-dibromo-5,5-dimethylhydantoin. All of the above brominating reagents can be used as dedicated reagents for the P3 bromination reaction, specifically substituting the hydrogen atom on the methyl group in 2,7-dibromo-9-methylanthracene. They exhibit high bromination selectivity, do not disrupt the anthracene ring skeleton and the aryl bromide structure at the 2,7 positions, have high bromination efficiency, produce few byproducts, are easy to separate, and are readily available and stable, allowing for flexible selection according to process requirements.

[0078] Furthermore, the initiator is selected from at least one of benzoyl peroxide, dicumyl peroxide, and azobisisobutyronitrile. These initiators can efficiently initiate bromination reactions, shorten the reaction induction period, and improve the efficiency of the bromination reaction; they exhibit high initiation selectivity and do not initiate side reactions such as anthracene ring bromination or ring-opening; all initiators are readily available, require small amounts, and easily decompose after the reaction, leaving no impurities and ensuring the purity of 2,7-dibromo-9-(bromomethyl)anthracene.

[0079] Furthermore, the haloalkane solvent is selected from at least one of carbon tetrachloride, dichloromethane, 1,2-dichloroethane, and 1,1,2-trichloroethane. These haloalkane solvents can efficiently dissolve 2,7-dibromo-9-methylanthracene, brominating reagents, and initiators, are suitable for the temperature requirements of bromination reactions, and provide a stable homogeneous environment for the reaction; they do not participate in the bromination reaction, do not damage the anthracene ring skeleton and aryl bromide structure, and the solvent can be easily separated by vacuum concentration, improving post-processing efficiency.

[0080] Furthermore, the potassium salt is selected from at least one of potassium acetate, potassium carbonate, and potassium bicarbonate. These potassium salts, as specialized reagents for transesterification reactions, can efficiently promote the transesterification reaction of 2,7-dibromo-9-(bromomethyl)anthracene, exhibiting high selectivity, without disrupting the anthracene ring skeleton and aryl bromine structure; they are mildly alkaline, do not initiate hydrolysis side reactions, and are readily available and inexpensive. They are also easily separated after the reaction, without introducing impurities.

[0081] Furthermore, the phase transfer catalyst is selected from at least one of tetrabutylammonium bromide, tetrabutylammonium chloride, triethylbenzylammonium chloride, and polyethylene glycol. The aforementioned phase transfer catalyst can improve the reaction efficiency of the transesterification reaction, promote mass transfer between the aqueous phase (potassium salt) and the organic phase (substrate), avoid catalyst agglomeration, and ensure uniform reaction. It exhibits high catalytic activity, requires only a small amount, does not participate in the reaction, does not damage the substrate structure, and is easily separated in post-processing, significantly shortening the transesterification reaction time and reducing process costs.

[0082] Furthermore, the amide solvent is selected from at least one of N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMA), and N-methylpyrrolidone (NMP). These amide solvents can efficiently dissolve 2,7-dibromo-9-(bromomethyl)anthracene, potassium salts, and phase transfer catalysts, providing a stable and homogeneous environment for the transesterification reaction; they are suitable for the temperature requirements of the transesterification reaction, do not participate in the reaction, do not damage the core structure of the substrate, have good solvent stability, facilitate subsequent extraction and separation, and improve process applicability.

[0083] Furthermore, the alkaline reagent is selected from at least one of potassium hydroxide, sodium hydroxide, and potassium carbonate. These alkaline reagents, as specialized reagents for alkaline hydrolysis reactions, can efficiently promote the hydrolysis of methyl acetate (2,7-dibromoanthracene-9-yl)acetate, completely converting it into (2,7-dibromoanthracene-9-yl)methanol; the alkalinity is controllable, does not damage the anthracene ring skeleton and aryl bromine structure, avoids excessive hydrolysis side reactions, and various alkaline reagents are readily available, low in cost, and easy to neutralize and separate in post-processing.

[0084] Furthermore, the alcohol solvent is selected from at least one of methanol, ethanol, isopropanol, and ethylene glycol monomethyl ether. These alcohol solvents can efficiently dissolve methyl acetate (2,7-dibromoanthracene-9-yl) and alkaline reagents, providing a stable and homogeneous environment for the alkaline hydrolysis reaction; they are suitable for the temperature requirements of the hydrolysis reaction, do not participate in the reaction, do not damage the substrate structure, and are easily separated by vacuum concentration. They can be flexibly selected according to process requirements, improving process applicability.

[0085] Furthermore, the halocarbon solvent is selected from at least one of anhydrous dichloromethane, anhydrous chloroform, and anhydrous 1,2-dichloroethane. The aforementioned halocarbon solvent is an anhydrous solvent, avoiding interference from moisture in the Swern oxidation reaction and preventing the formation of byproducts; it efficiently dissolves oxaloyl chloride, dimethyl sulfoxide, and (2,7-dibromoanthracene-9-yl)methanol, is suitable for the temperature conditions of the Swern oxidation reaction, does not participate in the oxidation reaction, does not damage the substrate structure, and produces clear layers, facilitating subsequent washing and separation.

[0086] Furthermore, the organic amine is selected from at least one of triethylamine, tri-n-propylamine, diisopropylethylamine, and tributylamine. These organic amines, acting as acid-binding agents in the Swern oxidation reaction, can efficiently neutralize the acidic substances generated during the reaction, preventing these substances from damaging the target product and substrate structure. They do not participate in the oxidation reaction, do not introduce impurities, and are readily available and easily separated, allowing for flexible selection according to process requirements. This ensures a stable and controllable Swern oxidation reaction and improves the purity of the target product.

[0087] Furthermore, in the bromination reaction, the molar ratio of the brominating reagent to the 2,7-dibromo-9-methylanthracene is (1.05~1.3):1; the molar ratio of the initiator to the 2,7-dibromo-9-methylanthracene is (0.05~0.15):1; and the volume ratio of the haloalkane solvent to the molar amount of the 2,7-dibromo-9-methylanthracene is 2 mL / mmol~10 mL / mmol. Limiting the ratio of the brominating reagent to the 2,7-dibromo-9-methylanthracene in the bromination reaction ensures the bromination reaction proceeds fully; controlling the amounts of the initiator and the haloalkane solvent balances reaction efficiency and cost, ensuring the yield and purity of 2,7-dibromo-9-(bromomethyl)anthracene.

[0088] Furthermore, in the transesterification reaction, the molar ratio of the potassium salt reagent to the 2,7-dibromo-9-(bromomethyl)anthracene is (3~8):1; the molar ratio of the phase transfer catalyst to the 2,7-dibromo-9-(bromomethyl)anthracene is (0.2~1):1; and the volume ratio of the amide solvent to the molar ratio of the 2,7-dibromo-9-(bromomethyl)anthracene is 5 mL / mmol~20 mL / mmol. Limiting the proportions of the potassium salt reagent, 2,7-dibromo-9-(bromomethyl)anthracene, and phase transfer catalyst in the transesterification reaction ensures the complete progress of the transesterification reaction; controlling the amount of amide solvent optimizes the reaction environment and reduces post-processing difficulty, ensuring the purity of methyl acetate (2,7-dibromoanthracene-9-yl).

[0089] Furthermore, in the alkaline hydrolysis reaction, the molar ratio of the alkaline reagent to the methyl acetate (2,7-dibromoanthracene-9-yl) is (3~10):1; the volume ratio of the alcohol solvent to the molar amount of the methyl acetate (2,7-dibromoanthracene-9-yl) is 10 mL / mmol~30 mL / mmol. Limiting the ratio of the alkaline reagent to the methyl acetate in the alkaline hydrolysis reaction ensures the complete hydrolysis of the methyl acetate (2,7-dibromoanthracene-9-yl) to (2,7-dibromoanthracene-9-yl)methanol, avoiding incomplete hydrolysis due to insufficient alkaline reagent; controlling the amount of alcohol solvent improves reaction efficiency, simplifies the post-processing procedure, and ensures the purity of the hydrolysis product.

[0090] Furthermore, in the Swern oxidation reaction, the molar ratio of oxaloyl chloride to (2,7-dibromoanthracene-9-yl)methanol is (10~25):1; the molar ratio of dimethyl sulfoxide to (2,7-dibromoanthracene-9-yl)methanol is (30~40):1; the volume ratio of the haloalkanes solvent to the molar ratio of (2,7-dibromoanthracene-9-yl)methanol is 100 mL / mmol~200 mL / mmol; and the volume ratio of the organic amine to the molar ratio of (2,7-dibromoanthracene-9-yl)methanol is 50 mL / mmol~150 mL / mmol. The proportions of oxaloyl chloride, (2,7-dibromoanthracene-9-yl)methanol, and dimethyl sulfoxide in the Swern oxidation reaction were limited to ensure the complete oxidation of (2,7-dibromoanthracene-9-yl)methanol to 2,7-dibromoanthracene-9-carboxaldehyde. The amounts of halogenated hydrocarbon solvents and organic amines were controlled to neutralize acidic impurities, avoid side reactions, and ensure the structural integrity and purity of the target product, 2,7-dibromoanthracene-9-carboxaldehyde.

[0091] The technical solution of the present invention will be further described below with reference to specific embodiments and comparative examples. All reagents used in the embodiments are commercially available or synthesized by conventional methods and can be used directly without further processing. The instruments used in the embodiments are also commercially available.

[0092] Example 1 This embodiment provides an eight-membered ring fused fluoroboron dipyrrole compound, which is prepared by the following steps: Preparation of S1, 2-bromo-7-(3,5-di-tert-butylphenyl)anthracene-9-carboxaldehyde: 543 mg of 2,7-dibromoanthracene-9-carboxaldehyde (prepared in step S0), 293 mg of 3,5-di-tert-butylphenylboronic acid, 265 mg of sodium carbonate, 25 mL of 1,4-dioxane, and 5 mL of water were added to a Shrek reaction flask. The reaction mixture was bubbled with nitrogen for 20 min to displace air from the system. Then, 45.7 mg of [1,1'-bis(diphenylphosphine)ferrocene]palladium dichloride was added to the reaction system, and the reaction mixture was heated to 90 °C and reacted for 17 h. After the reaction was completed, the reaction solution was brought to room temperature, poured into water and extracted three times with dichloromethane, and the organic phase was collected. The organic phase was dried over anhydrous sodium sulfate and concentrated under reduced pressure to remove the solvent. The crude product was purified by column chromatography to obtain 270 mg of 2-bromo-7-(3,5-di-tert-butylphenyl)anthracene-9-carboxaldehyde, a yellow solid with a yield of 38%. The specific synthetic route is shown in Formula II. (II).

[0093] Preparation of S2, 2-(3,5-di-tert-butylphenyl)-1H-pyrrole: In a Shrek flask, 2 g of 1-Boc-pyrrole-2-boric acid, 1.3 g of 3,5-di-tert-butylbromobenzene, 4.7 g of cesium carbonate, 52 mL of toluene, and 5.2 mL of methanol were added. The reaction mixture was bubbled with nitrogen for 20 min to displace air from the system. Then, 139 mg of tetrakis(triphenylphosphine)palladium was added to the reaction system. The reaction mixture was heated to 120 °C and stirred at this temperature for approximately 12 h (overnight). After the reaction was complete, the reaction solution was cooled to room temperature and poured into water. The solution was extracted three times with dichloromethane, and the organic phase was collected. The organic phase was dried over anhydrous sodium sulfate, concentrated under reduced pressure to remove the solvent, and the crude product was purified by column chromatography to obtain 960 mg of 2-(3,5-di-tert-butylphenyl)-1H-pyrrole, a white solid, with a yield of 78%. The specific synthetic route is shown in Formula III. (III).

[0094] Preparation of reaction intermediate BA (S3): 270 mg of 2-bromo-7-(3,5-di-tert-butylphenyl)anthracene-9-carboxaldehyde (prepared in step S1) and 111 mL of anhydrous dichloromethane were added to a Shrek reaction flask. The reaction mixture was bubbled with nitrogen for 10 min to purge air. Then, 321 mg of 2-(3,5-di-tert-butylphenyl)-1H-pyrrole (prepared in step S2) and 0.15 mL of trifluoroacetic acid were added to the flask, and the reaction was allowed to proceed at room temperature for 2 h. After the reaction was complete, a saturated sodium bicarbonate aqueous solution was added to quench the reaction, and the organic phase was collected. The collected organic phase was dried over anhydrous sodium sulfate and concentrated under reduced pressure to obtain the first crude product. Under nitrogen atmosphere, the first crude product and 100 mL of anhydrous dichloromethane were added to a Shrek reaction flask, and the reaction mixture was bubbled with nitrogen for 10 min. 169 mg of 2,3-dichloro-5,6-dicyano-1,4-benzoquinone was added to the reaction flask, and the reaction was carried out at room temperature for 1 h. Then, 6.8 mL of triethylamine and 9.1 mL of boron trifluoride diethyl ether complex were added sequentially to the reaction solution to carry out a fluorination-boronization cyclization reaction for 4 h. After the reaction was completed, the reaction solution was concentrated under reduced pressure to remove most of the solvent. The residue was purified by column chromatography to give 380 mg of compound BA as a purple solid, with a yield of 42%. The synthetic route is shown in Formula IV. (IV).

[0095] S4. Preparation of the precursor compound BBA: Under a nitrogen atmosphere, 24.5 mg of bis(1,5-cyclooctadiene)nickel, 13.9 mg of 2,2'-bipyridine, 0.011 mL of 1,5-cyclooctadiene, and 6 mL of N,N-dimethylformamide were added to a Shrek reaction flask. The reaction mixture was heated to 55 °C and reacted for 30 min to preactivate the catalyst. Subsequently, 60 mg of the reaction intermediate compound BA obtained in step S3 was dissolved in 12 mL of anhydrous toluene and then slowly added dropwise to the above-activated catalyst system. After the addition was complete, the reaction system was heated to 80 °C and reacted for 4 h. After the reaction was completed, the reaction solution was cooled to room temperature and diluted with ethyl acetate. The organic phase was washed with saturated ammonium chloride solution and saturated brine. The washed organic phase was dried over anhydrous sodium sulfate, concentrated under reduced pressure to remove the solvent, and the crude product was purified by column chromatography to obtain 40 mg of compound BBA as a purple solid with a yield of 71%. The synthetic route is shown in Formula V. (V).

[0096] Preparation of compound OBNG (S5): Under a nitrogen atmosphere, 20 mg of the precursor compound BBA prepared in step S4 and 7.1 mL of anhydrous dichloromethane were added to a Shrek reaction flask. 104 mg of ferric chloride was dissolved in 2.1 mL of nitromethane to prepare an oxidant solution. This oxidant solution was slowly added dropwise to the reaction solution containing the precursor compound BBA at 0 °C. After the addition was complete, the reaction mixture was removed from the ice bath and allowed to return to room temperature naturally. The reaction was then stirred for 20 min at room temperature. After the reaction was complete, saturated sodium bicarbonate solution was added to quench the reaction mixture, and the mixture was extracted three times with dichloromethane. The organic phase was collected. The collected organic phase was dried over anhydrous sodium sulfate, concentrated under reduced pressure to remove the solvent, and the crude product was purified by column chromatography to obtain 25 mg of an eight-membered ring fused fluoroboron dipyrrole compound, a green solid, with a yield of 34%, denoted as OBNG. The synthetic route is shown in Formula VI. (VI).

[0097] Example 2 This embodiment provides an eight-membered ring fused fluoroboron dipyrrole compound, the preparation method of which differs from that of Example 1 in step S1: Preparation of S1, 2-bromo-7-(3,5-di-tert-butylphenyl)anthracene-9-carboxaldehyde: 1.00 g of 2,7-dibromoanthracene-9-carboxaldehyde, 515 mg of 3,5-di-tert-butylphenylboronic acid, 569 mg of potassium carbonate, 20 mL of 1,4-dioxane, and 2 mL of water were added to a Shrek flask. The mixture was bubbled with nitrogen for 20 min to displace air. Then, 15.9 mg of tetra(triphenylphosphine)palladium was added, and the reaction mixture was heated to 90 °C and stirred for 17 h. After the reaction was complete, the mixture was allowed to return to room temperature, poured into water, and extracted three times with dichloromethane. The combined organic phases were dried over anhydrous sodium sulfate and concentrated under reduced pressure. The crude product was purified by column chromatography (petroleum ether / ethyl acetate gradient elution) to give 0.35 g of a yellow solid, with a yield of approximately 30%. Steps S2, S3, S4, and S5 are the same as in Example 1.

[0098] Example 3 This embodiment provides an eight-membered ring fused fluoroboron dipyrrole compound, the preparation method of which differs from that of Example 1 in step S2: Preparation of S2, 2-(3,5-di-tert-butylphenyl)-1H-pyrrole: In a Shrek flask, 1.00 g of 1-Boc-pyrrole-2-boric acid, 0.632 g of 3,5-di-tert-butylbromobenzene, 1.25 g of potassium carbonate, 12 mL of toluene, and 2.4 mL of methanol were added. The mixture was bubbled with nitrogen for 20 min to purge air. Then, 13.6 mg of tetrakis(triphenylphosphine)palladium was added, and the reaction mixture was heated to 100 °C and stirred for 12 h. After the reaction was complete, the mixture was cooled to room temperature, poured into water, and extracted three times with dichloromethane. The combined organic phases were dried over anhydrous sodium sulfate and concentrated under reduced pressure. The crude product was purified by column chromatography (petroleum ether / ethyl acetate gradient elution) to give 0.45 g of a white solid, with a yield of approximately 75%.

[0099] Steps S1, S3, S4, and S5 are the same as in Example 1.

[0100] Example 4 This embodiment provides an eight-membered ring fused fluoroboron dipyrrole compound, the preparation method of which differs from that of Example 1 in step S3: S3. Preparation of reaction intermediate BA: 200 mg of 2-bromo-7-(3,5-di-tert-butylphenyl)anthracene-9-carboxaldehyde and 84.6 mL of anhydrous dichloromethane were added to a reaction flask, and the mixture was bubbled with nitrogen for 10 min to displace air. 200 mg of 2-(3,5-di-tert-butylphenyl)-1H-pyrrole and 0.0048 mL of trifluoroacetic acid were added. The reaction was stirred at room temperature (approximately 25 °C) for 2 h. After the reaction was complete, a saturated sodium bicarbonate aqueous solution was added to quench the reaction, the organic phase was separated, dried over anhydrous sodium sulfate, and concentrated under reduced pressure to obtain the first-step crude product. The first crude product was dissolved in 84.6 mL of anhydrous dichloromethane under nitrogen atmosphere, and the mixture was bubbled with nitrogen for 10 min. 96 mg of 2,3-dichloro-5,6-dicyano-1,4-benzoquinone was added, and the reaction was stirred at room temperature for 1 h. 5.8 mL of triethylamine and 6.0 mL of boron trifluoride diethyl ether complex were added sequentially, and the reaction was stirred at room temperature for 4 h. After the reaction was completed, most of the solvent was removed by concentration under reduced pressure. The residue was then purified by column chromatography (eluent: petroleum ether / dichloromethane gradient) to obtain a purple solid (compound BA), with an estimated yield of about 40%.

[0101] Steps S1, S2, S4 and S5 are identical to those in Example 1.

[0102] Example 5 This embodiment provides an eight-membered ring fused fluoroboron dipyrrole compound, the preparation method of which differs from that of Example 1 in step S4: S4. Preparation of the precursor compound BBA: Under a nitrogen atmosphere, 19.6 mg of bis(1,5-cyclooctadiene)nickel, 11.1 mg of 2,2'-bipyridine, 0.006 mL of 1,5-cyclooctadiene, and 6 mL of N,N-dimethylformamide were added to a Shrek reaction flask. The reaction mixture was heated to 60 °C and reacted for 20 min to activate the catalyst. Subsequently, 60 mg of the reaction intermediate compound BA obtained in step S3 was dissolved in 6 mL of anhydrous toluene and slowly added dropwise to the activated catalyst system. After the addition was complete, the reaction system was heated to 85 °C and reacted for 4 hours. After the reaction was completed, the reaction solution was cooled to room temperature and diluted with ethyl acetate. The organic phase was washed successively with saturated ammonium chloride solution and saturated brine. The washed organic phase was dried over anhydrous sodium sulfate, concentrated under reduced pressure to remove the solvent, and the crude product was purified by column chromatography to obtain approximately 41 mg of compound BBA as a purple solid, with a yield of approximately 70%.

[0103] Steps S1, S2, S3 and S5 are the same as in Example 1.

[0104] Example 6 This embodiment provides an eight-membered ring fused fluoroboron dipyrrole compound, the preparation method of which differs from that of Example 1 in step S5: Preparation of compound OBNG (S5): Under a nitrogen atmosphere, 20 mg of the precursor compound BBA prepared in step S4 and 2.1 mL of anhydrous dichloromethane were added to a Shrek reaction flask. 104 mg of ferric chloride was dissolved in 0.53 mL of nitromethane to prepare an oxidizing agent solution. This oxidizing agent solution was slowly added dropwise to the reaction solution containing the precursor compound BBA at -5 °C. After the addition was complete, the reaction mixture was removed from the cold bath and allowed to naturally warm to 10 °C, where it was stirred for 40 min. After the reaction was complete, saturated sodium bicarbonate solution was added to quench the reaction mixture, and the mixture was extracted three times with dichloromethane. The organic phase was collected. The collected organic phase was dried over anhydrous sodium sulfate, concentrated under reduced pressure to remove the solvent, and the crude product was purified by column chromatography to obtain approximately 22 mg of the eight-membered ring-fused fluoroboron dipyrrole compound OBNG as a green solid, with a yield of approximately 32%.

[0105] Steps S1, S2, S3 and S4 are the same as in Example 1.

[0106] Example 7 This embodiment provides a method for preparing 2,7-dibromoanthracene-9-carboxaldehyde, including the following steps: P1. Preparation of 5-bromo-2-(4-bromobenzyl)benzaldehyde: In a Shrek flask, 2 g of 5-bromo-2-methylbenzaldehyde, 4.25 g of 1-bromo-4-iodobenzene, 3.31 g of silver trifluoroacetate, 224 mg of palladium acetate, 300 mg of glycine, 90 mL of acetic acid, and 10 mL of water were added sequentially. The reaction mixture was stirred at room temperature for 10 min, followed by heating at 90 °C for 36 h in air. After the reaction was complete, the reaction solution was brought to room temperature and filtered through a short silica gel column. The filtrate was concentrated under reduced pressure to remove the solvent, and the crude product was purified by column chromatography to give 2.3 g of 5-bromo-2-(4-bromobenzyl)benzaldehyde as an orange oily liquid with a yield of 65%. The synthesis process is shown in Formula VII. (VII).

[0107] P2. Preparation of 2,7-dibromo-9-methylanthracene: P2.1 Under a nitrogen atmosphere, 7.08 g of 5-bromo-2-(4-bromobenzyl)benzaldehyde and 150 mL of anhydrous tetrahydrofuran were added to a Shrek reaction flask. The reaction mixture was cooled to 0 °C, and 10 mL of a 3 mol / L solution of magnesium methyl bromide diethyl ether was added dropwise. After the addition was complete, the cold bath was removed, the reaction mixture was allowed to return to room temperature, and the reaction was stirred overnight. After the reaction was complete, water was slowly added to quench the reaction, and the mixture was extracted three times with dichloromethane. The organic phase was collected. The organic phase was concentrated by vacuum distillation to obtain the first crude product. Then, under a nitrogen atmosphere, the first crude product and 200 mL of anhydrous dichloromethane were added to a Shrek reaction flask. After the first crude product was added, the mixture was cooled to -78 °C, and 2.64 mL of trifluoromethanesulfonic acid was added. The reaction mixture was stirred at this temperature for 1 h, then the cold bath was removed, the reaction mixture was allowed to return to room temperature naturally, and the reaction was stirred for another 2 h. After the reaction was complete, water was slowly added to quench the reaction, and the mixture was extracted three times with dichloromethane. The organic phase was collected. The organic phase was concentrated by vacuum distillation and then washed with methanol to obtain 4.7 g of the second crude product, the synthetic route of which is shown in formula VIII: (VIII).

[0108] P2.2 Then, under a nitrogen atmosphere, 4.7 g of the above-mentioned second crude product, 3.65 g of 2,3-dichloro-5,6-dicyano-1,4-benzoquinone, and 130 mL of anhydrous toluene were added to a Shrek reaction flask. The reaction mixture was heated to 100 °C and reacted for 3 h. After the reaction was completed, the reaction solution was brought back to room temperature, and the organic phase was concentrated by vacuum distillation and purified by column chromatography to obtain 3.43 g of 2,7-dibromo-9-methylanthracene as a yellow solid with a yield of 49%. The synthetic route is shown in Formula IX: (IX).

[0109] P3. Preparation of 2,7-dibromoanthracene-9-carboxaldehyde: P3.1 Preparation of 2,7-dibromo-9-(bromomethyl)anthracene: Under a nitrogen atmosphere, 4 g of 2,7-dibromo-9-methylanthracene prepared in step P2, 2.29 g of N-bromosuccinimide (NBS), 311 mg of benzoyl peroxide, and 85 mL of carbon tetrachloride were added to a Shrek reaction flask. The reaction mixture was heated to 90 °C and reacted for 12 h. After the reaction was completed, the reaction solution was brought back to room temperature, and most of the solvent was removed by vacuum distillation. The residue was separated by column chromatography to obtain 3.1 g of 2,7-dibromo-9-(bromomethyl)anthracene, a yellow solid, with a yield of 84%. The synthetic route is shown in Formula X. (X).

[0110] P3.2 Preparation of (2,7-dibromoanthracene-9-yl)methyl acetate: Under a nitrogen atmosphere, 3.1 g of 2,7-dibromo-9-(bromomethyl)anthracene obtained in step P3.1, 3.54 g of potassium acetate, 1.17 g of tetrabutylammonium bromide, and 120 mL of N,N-dimethylformamide were added to a Shrek reaction flask. The reaction mixture was heated to 100 °C and reacted for 12 h. After the reaction was completed, the reaction solution was brought to room temperature, quenched with saturated ammonium chloride solution, and extracted three times with ethyl acetate. The organic phase was collected. After drying the organic phase with anhydrous sodium sulfate, the solvent was removed by concentration under reduced pressure. The crude product was purified by column chromatography to obtain 2.9 g of (2,7-dibromoanthracene-9-yl)methyl acetate, a yellow solid, with a yield of 98%. The synthetic route is shown in Formula XI. (XI).

[0111] P3.3 Preparation of (2,7-dibromoanthracene-9-yl)methanol: Under a nitrogen atmosphere, 2.9 g of the aforementioned methyl acetate (2,7-dibromoanthracene-9-yl), 1.99 g of potassium hydroxide, and 150 mL of methanol were added to a Shrek reaction flask. The reaction mixture was heated to 80 °C and reacted for 12 h. After the reaction was completed, the reaction solution was brought back to room temperature, and most of the methanol solvent was removed by vacuum distillation. Deionized water was added to the concentrated residue, and after stirring, a solid precipitated. The solid was filtered, collected, and washed with a small amount of cold water to obtain 2.47 g of (2,7-dibromoanthracene-9-yl)methanol, a white solid with a yield of 95%. The synthetic route is shown in Formula XII: (XII) P3.4 Preparation of 2,7-dibromoanthracene-9-carboxaldehyde: Under a nitrogen atmosphere, 0.53 mL of oxaloyl chloride and 50 mL of anhydrous dichloromethane were added to a Shrek reaction flask. After cooling the reaction mixture to -78 °C, 0.89 mL of anhydrous dimethyl sulfoxide was slowly added, and the reaction was allowed to proceed for 15 min. Then, 183 mg of (2,7-dibromoanthracene-9-yl)methanol obtained in step P3.3 was added to the reaction flask in one go, and the reaction was allowed to proceed at -78 °C for 2 h. Next, 1.73 mL of triethylamine was slowly added to the reaction flask, and after the addition was complete, the reaction was allowed to proceed at -78 °C for another 1 h. The reaction solution was then brought to room temperature and stirred for another 30 min. After the reaction was completed, the reaction solution was concentrated under reduced pressure to remove most of the solvent. The residue was dissolved in ethyl acetate and then washed successively with saturated sodium bicarbonate aqueous solution and saturated brine. After drying the organic phase with anhydrous sodium sulfate, it was concentrated under reduced pressure. The crude product was purified by column chromatography to give 146 mg of 2,7-dibromoanthracene-9-carboxaldehyde, a yellow solid, in 80% yield. The synthetic route is shown in Formula XIII. (XIII) Example 8 This embodiment provides a method for preparing 2,7-dibromoanthracene-9-carboxaldehyde, which differs from Example 12 in step P1: P1. Preparation of 5-bromo-2-(4-bromobenzyl)benzaldehyde: In a Shrek reaction flask, 2 g of 5-bromo-2-methylbenzaldehyde, 2.84 g of 1-bromo-4-iodobenzene, 2.22 g of silver trifluoroacetate, 113 mg of palladium acetate, 151 mg of glycine, 44.7 mL of acetic acid, and 5.6 mL of water were added sequentially. The reaction mixture in the flask was stirred at room temperature for 10 min, and then heated at 85 °C for 36 h in air. After the reaction was completed, the reaction solution was brought to room temperature and filtered through a short silica gel column. The filtrate was concentrated under reduced pressure to remove the solvent, and the crude product was purified by column chromatography to give 2.1 g of 5-bromo-2-(4-bromobenzyl)benzaldehyde as an orange oily liquid, with a yield of 59%.

[0112] Steps P2 and P3 are the same as in Example 7.

[0113] Example 9 This embodiment provides a method for preparing 2,7-dibromoanthracene-9-carboxaldehyde, which differs from Example 12 in step P2: P2. Preparation of 2,7-dibromo-9-methylanthracene: Under a nitrogen atmosphere, 7.08 g of 5-bromo-2-(4-bromobenzyl)benzaldehyde and 100 mL of anhydrous diethyl ether were added to a Shrek flask. The reaction mixture was cooled to -5 °C, and 8.0 mL of a 3.0 mol / L solution of magnesium methyl iodide diethyl ether was added dropwise. After the addition was complete, the cold bath was removed, the reaction mixture was allowed to return to room temperature, and the reaction was stirred overnight. After the reaction was complete, water was slowly added to quench the reaction, and the mixture was extracted three times with dichloromethane. The organic phase was collected. The organic phase was concentrated by vacuum distillation to obtain the first crude product. Then, under a nitrogen atmosphere, the first crude product and 100 mL of anhydrous chloroform were added to a Shrek flask. After the first crude product was added, the mixture was cooled to -85 °C, and 1.30 mL of methanesulfonic acid was added. The reaction mixture was stirred at this temperature for 1 h, then the cold bath was removed, the reaction mixture was allowed to return to room temperature naturally, and the reaction was stirred for another 2 h. After the reaction was complete, water was slowly added to quench the reaction, and the mixture was extracted three times with dichloromethane. The organic phase was collected. The organic phase was concentrated by vacuum distillation and washed with methanol to obtain 4.7 g of the second crude product. Then, under a nitrogen atmosphere, the second crude product, 3.93 g of tetrachlorobenzoquinone, and 100 mL of xylene were added to a Shrek flask. The reaction mixture was heated to 95 °C and reacted for 3 h. After the reaction was complete, the reaction solution was brought to room temperature, and the organic phase was concentrated by vacuum distillation and purified by column chromatography to obtain 3.2 g of 2,7-dibromo-9-methylanthracene as a yellow solid, with a yield of 46%.

[0114] Steps P1 and P3 are the same as in Example 7.

[0115] Example 10 This embodiment provides a method for preparing 2,7-dibromoanthracene-9-carboxaldehyde, which differs from Example 12 in step P3: P3. Preparation of 2,7-dibromoanthracene-9-carboxaldehyde: P3.1 Preparation of 2,7-dibromo-9-(bromomethyl)anthracene: Under a nitrogen atmosphere, 4 g of 2,7-dibromo-9-methylanthracene, 2.11 g of N-bromoacetamide, 201 mg of dicumyl peroxide, and 20 mL of 1,2-dichloroethane were added to a Shrek flask. The reaction mixture was heated to 85 °C and reacted for 12 h. After the reaction was completed, the reaction solution was brought back to room temperature, and most of the solvent was removed by vacuum distillation. The residue was separated by column chromatography to give 3.2 g of 2,7-dibromo-9-(bromomethyl)anthracene as a yellow solid, with a yield of 80%.

[0116] P3.2 Preparation of (2,7-dibromoanthracene-9-yl)methyl acetate: Under a nitrogen atmosphere, 3.2 g of 2,7-dibromo-9-(bromomethyl)anthracene, 2.85 g of potassium carbonate, 0.25 g of polyethylene glycol (PEG-400), and 35 mL of N-methylpyrrolidone were added to a Shrek reaction flask. The reaction mixture was heated to 95 °C and reacted for 12 h. After the reaction was completed, the reaction solution was brought to room temperature, quenched with saturated ammonium chloride solution, and extracted three times with ethyl acetate. The organic phase was collected. After drying the organic phase with anhydrous sodium sulfate, the solvent was removed by concentration under reduced pressure. The crude product was purified by column chromatography to obtain 2.7 g of (2,7-dibromoanthracene-9-yl)methyl acetate, a yellow solid, with a yield of 95%.

[0117] P3.3 Preparation of (2,7-dibromoanthracene-9-yl)methanol: Under a nitrogen atmosphere, 2.7 g of methyl (2,7-dibromoanthracene-9-yl)acetate, 0.90 g of sodium hydroxide, and 40 mL of ethanol were added to a Shrek reaction flask. The reaction mixture was heated to 75 °C and reacted for 12 h. After the reaction was completed, the reaction solution was brought to room temperature, and most of the solvent was removed by vacuum distillation. Deionized water was added to the concentrated residue, and after stirring, a solid precipitated. The solid was filtered, collected, and washed with a small amount of cold water to give 2.1 g of (2,7-dibromoanthracene-9-yl)methanol, a white solid, with a yield of 90%.

[0118] P3.4 Preparation of 2,7-dibromoanthracene-9-carboxaldehyde: Under a nitrogen atmosphere, 0.40 mL of oxaloyl chloride and 30 mL of anhydrous chloroform were added to a Shrek reaction flask. After cooling the reaction mixture to -85 °C, 0.62 mL of anhydrous dimethyl sulfoxide was slowly added, and the reaction was allowed to proceed for 15 min. Then, 183 mg of (2,7-dibromoanthracene-9-yl) methanol was added to the reaction flask in one go, and the reaction was allowed to proceed at -85 °C for 2 h. Next, 1.25 mL of tri-n-propylamine was slowly added to the reaction flask, and after the addition was complete, the reaction was allowed to proceed at -85 °C for another 1 h. The reaction solution was then brought to room temperature and stirred for another 30 min. After the reaction was completed, the reaction solution was concentrated under reduced pressure to remove most of the solvent. The residue was dissolved in ethyl acetate and then washed successively with saturated sodium bicarbonate aqueous solution and saturated brine. The organic phase was dried over anhydrous sodium sulfate and concentrated under reduced pressure. The crude product was purified by column chromatography to give 131 mg of 2,7-dibromoanthracene-9-carboxaldehyde, a yellow solid, with a yield of 67.3%.

[0119] Steps P1 and P2 are the same as in Example 7.

[0120] Performance Testing and Results Analysis The eight-membered ring fused fluoroboron dipyrrole compound OBNG prepared in Example 1 was subjected to 1H NMR spectroscopy, single crystal structure analysis, UV-Vis-NIR absorption spectroscopy, cyclic voltammetry, and anisotropic magnetic induction current density measurements. The test results are as follows: Figure 1 The 1H NMR spectrum of the eight-membered ring fused fluoroboron dipyrrole compound prepared in Example 1. The 1H NMR spectrum of compound OBNG (600 MHz, CD2C) l2 The data are as follows: δ 9.01(s,2H), 8.45(d,J=9.3 Hz,2H), 8.35(d,J=9.1 Hz,2H), 7.81(d,J=8.4 Hz,2H), 7.69(s,2H), 7.68(s,4H), 7.54(s,2H), 7.48(s,2H), 7.40(s,2H), 7.24(s,4H), 7.08(s,2H), 6.99(d,J=8.6 Hz,2H), 5.94(s,2H), 1.50(s,18H), 1.29(s,36H), 1.27(s,18H), 0.95(s,36H). (From...) Figure 1The data shows that in the high-field region (δ 0.95-1.50 ppm), four sets of sharp singlets appear, with an integral ratio of 36H:18H:36H:18H. These signals correspond to the tert-butyl (-C(CH3)3) hydrogen atoms on the four 3,5-di-tert-butylphenyl groups in the molecule. Due to the different chemical environments of these phenyl groups in the molecular skeleton (such as being attached to the 2 and 7 positions of the anthracene ring, or the 2 position of the pyrrole ring), the chemical shifts of their tert-butyl hydrogen atoms exhibit subtle differences, which is perfectly consistent with the complex and asymmetric fused-ring structure of the target molecule. In the mid-to-low-field aromatic region and the characteristic hydrogen atom region (δ 5.94-9.01 ppm), the singlet (2H) at δ 9.01 ppm is at the lowest field and is usually attributed to hydrogen atoms deshielded by strong electron-withdrawing groups (such as carbonyl groups or fused-ring large π systems). Here, it may correspond to hydrogen atoms near the eight-membered ring or at specific positions on the fluoroboron dipyrrole core. Doublets (d) at δ 8.45, 8.35, 7.81, and 6.99 ppm, with coupling constants (J ≈ 8-9 Hz), indicate the presence of ortho-coupled aromatic hydrogen atoms, originating from hydrogen atoms in fused aromatic systems such as anthracene rings. A series of singlets (s) and signals at δ 7.69, 7.68, 7.54, 7.48, 7.40, 7.24, and 7.08 ppm correspond to multiple hydrogen atoms on the benzene ring of 3,5-di-tert-butylphenyl (due to the steric hindrance of the tert-butyl group, the remaining two hydrogen atoms on the benzene ring have equivalent chemical environments, exhibiting singlets), as well as isolated hydrogen atoms on the fused ring skeleton that are not ortho-coupled with other protons. The singlet (2H) at δ 5.94 ppm is a relatively characteristic signal, possibly belonging to hydrogen atoms in the fluoroboron dipyrrole (BODIPY) core, either bonded to pyrrole nitrogen or in a specific methylene environment. The complexity of the spectrum reflects the complexity, low symmetry, and double-helix chirality of the OBNG molecular structure. Furthermore, the high resolution and sharp signal of the spectrum indicate high product purity. The proton NMR data perfectly match the molecular structure of the target compound, eight-membered ring fused fluoroboron dipyrrole (OBNG), confirming the successful synthesis of its chemical structure and its high purity.

[0121] Figure 2 This is the single-crystal structure spectrum of the eight-membered ring fused fluoroboron dipyrrole compound prepared in Example 1. Figure 2In the image, (a) is a front view of the single-crystal structure of the eight-membered ring fused fluoroboron dipyrrole compound, and (b) is a side view of the single-crystal structure of the eight-membered ring fused fluoroboron dipyrrole compound. (a) clearly shows that an eight-membered ring has been successfully constructed and fused between the fluoroboron dipyrrole (BODIPY) core and the extended anthracene ring system. This eight-membered ring does not exist in a planar form but exhibits a certain twisted structure to alleviate intra-ring tension. The introduction of this non-planar eight-membered ring is the key structural basis for adjusting the electronic structure of the entire π-conjugated system and achieving a redshift of the absorption spectrum to the near-infrared II (NIR-II) region. (b) visually reveals the double-helix topology of the eight-membered ring fused fluoroboron dipyrrole compound molecule, i.e., the molecular skeleton is not laid flat on a plane but twisted and coiled around a virtual central axis like two helical bands. This twisting results in the lack of a symmetry plane and a center of symmetry in the molecule, thus producing inherent chirality. This confirms that the synthesized OBNG is a chiral molecule, theoretically possessing a pair of enantiomers. In the eight-membered ring fused fluoroboron dipyrrole compound, all rings (benzene ring, anthracene ring, pyrrole ring, eight-membered ring, and BODIPY ring) are fused together, forming a completely rigid, extended planar large π-conjugated system. This fully fused structure and low symmetry minimize non-radiative energy dissipation caused by intramolecular vibrations and rotations and enhance the strength of transition oscillators, which is the structural reason for the compound's high stability and strong near-infrared II absorption (high molar extinction coefficient).

[0122] Figure 3 The image shows the UV-Vis-NIR absorption spectrum of the eight-membered ring fused fluoroboron dipyrrole compound prepared in Example 1. Figure 3 In the figure, (a) is an eight-membered ring fused fluoroboron dipyrrole compound in 1×10 -5 (a) shows the UV-Vis-NIR absorption spectrum of the M toluene solution, and (b) shows the UV-Vis-NIR absorption spectra of the eight-membered ring fused fluoroboron dipyrrole compound in dichloromethane (DCM), hexane, tetrahydrofuran (THF), and toluene. As shown in the figure, the eight-membered ring fused fluoroboron dipyrrole compound OBNG exhibits significant absorption across a broad wavelength range of 400 nm to 1600 nm, covering the UV to NIR II region. The absorption peak tail is close to 1600 nm, and the molar extinction coefficient at the maximum absorption peak is close to 10000 M. -1 cm -1 This characteristic confirms its successful design as a broad-spectrum absorption, near-infrared region-covering, region-II organic functional molecule. (In 1×10⁻⁶) -5In toluene solution, the eight-membered ring fused fluoroboron dipyrrole compound exhibits a strong characteristic absorption peak in the 400-600 nm region, corresponding to the π→π* electronic transitions of the fluoroboron dipyrrole (BODIPY) core, anthracene ring, and 3,5-di-tert-butylphenyl group, as well as the characteristic absorption of the conjugated aromatic ring system formed after the eight-membered ring fusion. OBNG shows a broad and gentle absorption band in the near-infrared region of 600-1600 nm, corresponding to the low-energy π→π* transitions of the large π-conjugated system and intramolecular charge transfer transitions. Near-infrared absorption is a hallmark feature distinguishing OBNG from ordinary BODIPY derivatives, demonstrating that the conjugated system is significantly expanded after eight-membered ring fusion, possessing near-infrared absorption potential. In four different polar solvents (n-hexane, toluene, tetrahydrofuran, and dichloromethane) (1×10⁻⁶), OBNG was also tested. -5 The absorption peak shapes and relative intensities of M and OBNG are basically the same, with only a slight red shift as the solvent polarity increases, indicating a very weak solvent effect; this proves that the molecule has a rigid conjugated skeleton, is structurally stable and does not aggregate in solvents of different polarities, and has good solubility.

[0123] Figure 4 This is a cyclic voltammogram of the eight-membered ring fused fluoroboron dipyrrole compound prepared in Example 1 in dichloromethane solvent. The cyclic voltammogram test conditions were as follows: [Fc] + / Fc (ferrocene / ferrocene cation) was used as the reference electrode, with a potential range of -1.5 to 1.0 V. A glassy carbon electrode was used as the working electrode, and a platinum wire was used as the counter electrode. The test was conducted under a nitrogen atmosphere at a scan rate of 50 mV / s. As shown in the figure, OBNG exhibits two aligned reversible redox peaks in the potential range of -1.5 to 1.0 V. The reduction peak is: E... red1 =−1.01V, E red2 =−0.77 V, corresponding to the stepwise single-electron reduction of two BODIPY units in the molecule, proving that the molecule has a low LUMO energy level and possesses electron acceptor properties; Oxidation peak: E ox1 =0.22 V, E ox2 =0.67 V, corresponding to stepwise single-electron oxidation of the fused-ring conjugated system, proving that the molecular HOMO energy level is moderate and possesses electron donor characteristics. The CV curve has a regular peak shape and no obvious current decay, indicating that the redox process is quasi-reversible, demonstrating that OBNG has excellent electrochemical stability in DCM solvent, possesses bipolar organic semiconductor characteristics, and its structure is consistent with the target product, making it suitable for use in the field of optoelectronic functional materials.

[0124] Figure 5This is an anisotropic magnetic induction current density (ACID) map of the eight-membered ring fused fluoroboron dipyrrole compound prepared in Example 1. The ACID map is an electronic structure characterization diagram obtained through theoretical calculations combined with experimental structures, calculated by measuring the induced current density of the molecule under an external magnetic field. In the map, the yellow area represents the induced current of π electrons, and the green arrows indicate the direction of the induced current generated by the software. To clearly show the direction, the green arrows have been manually enlarged to red and blue. The red arrows represent clockwise ring currents, indicating aromaticity; the blue arrows represent counterclockwise ring currents, indicating antiaromaticity. The eight-membered ring in the entire molecular skeleton of the OBNG molecule exhibits counterclockwise ring currents, indicating antiaromaticity, while the remaining parts exhibit clockwise ring currents, indicating aromaticity.

[0125] Figure 5 The OBNG molecule exhibits a large-area, continuous, strong yellow induced current in its central and fused regions, corresponding to the large π-conjugated framework of the fluoroboron dipyrrole (BODIPY) core, anthracene ring, and eight-membered ring fused system. The strong current around the BODIPY pyrrole ring and the BF2 coordination structure verifies the aromaticity of the BODIPY core. The strong current in the anthracene ring region is a hallmark feature of typical fused-ring aromatic hydrocarbons. The strong induced current in the eight-membered ring region proves that the intramolecular oxidative dehydrogenation cyclization reaction successfully constructed an anti-aromatic eight-membered ring fused structure. The highly delocalized and continuously conjugated π electrons between the eight-membered ring, BODIPY, and anthracene ring are key structural features that distinguish OBNG from ordinary BODIPY derivatives. The strong induced current demonstrates the well-developed conjugated system and excellent aromaticity of the OBNG molecule, perfectly matching its near-infrared broad absorption in UV-Vis-NIR and bipolar electrochemical characteristics in CV.

[0126] Figure 5 The 3,5-di-tert-butylphenyl regions on both sides of the OBNG molecule exhibit a moderate green induced current, corresponding to the delocalization of π electrons on the benzene ring of the 3,5-di-tert-butylphenyl group. The tert-butyl group, being a saturated alkyl group (white / gray), lacks π electrons and thus exhibits no induced current, consistent with the non-aromatic nature of alkyl groups. This indicates that the Suzuki coupling reaction successfully introduced 3,5-di-tert-butylphenyl, and the benzene ring of the substituent retains its aromaticity without disrupting the core conjugated system. The areas near the BF2 group and the local non-conjugated sites of the eight-membered ring in the OBNG molecule exhibit weak red / blue induced currents, with no large-area strong blue anti-induced current (anti-aromatic characteristic). This demonstrates that the eight-membered ring fused structure lacks anti-aromatic properties and exhibits high stability, consistent with the bonding rules of organic aromatic compounds; the distribution of the weak current regions is reasonable and completely consistent with the target molecule structure. The OBNG molecule surrounding the tert-butyl group (-C(CH3)3) appears white / gray and has no induced current. The steric hindrance of the tert-butyl group (the white / gray region extends outward from the molecule) does not affect the delocalization of π electrons in the core conjugated system. On the contrary, it can protect the core aromatic skeleton, inhibit intermolecular aggregation, and improve product stability, which is consistent with the steric hindrance characteristics of the single crystal structure.

[0127] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An eight-membered ring fused fluoroboron dipyrrole compound, characterized in that, It has a structure as shown in Equation I: 。 2. The eight-membered ring fused fluoroboron dipyrrole compound according to claim 1, characterized in that, The eight-membered ring fused fluoroboron dipyrrole compound is synthesized by: using 2,7-dibromoanthracene-9-carboxaldehyde as a precursor, introducing 3,5-di-tert-butylbenzene at position 2 via Suzuki coupling reaction, constructing fluoroboron dipyrrole at position 9 via condensation, undergoing Yamamoto coupling reaction at position 7 via palladium catalysis, and then synthesizing it via an intramolecular oxidative dehydrogenation cyclization reaction initiated by ferric chloride.

3. A method for preparing the eight-membered ring fused fluoroboron dipyrrole compound as described in claim 1 or 2, characterized in that, Includes the following steps: S1, 2,7-dibromoanthracene-9-carboxaldehyde and 3,5-di-tert-butylphenylboronic acid were coupled via a palladium-catalyzed Suzuki reaction to give 2-bromo-7-(3,5-di-tert-butylphenyl)anthracene-9-carboxaldehyde; S2, 1-Boc-pyrrole-2-boronic acid and 3,5-di-tert-butylbromobenzene were coupled via a palladium-catalyzed Suzuki reaction to give 2-(3,5-di-tert-butylphenyl)-1H-pyrrole. S3. The 2-bromo-7-(3,5-di-tert-butylphenyl)anthracene-9-carboxaldehyde described in step S1 undergoes a condensation reaction with the 2-(3,5-di-tert-butylphenyl)-1H-pyrrole described in step S2, and then undergoes an oxidation and fluorinated boron cyclization reaction to construct a fluoroboron dipyrrole unit, yielding the reaction intermediate compound BA. S4. The reaction intermediate compound BA described in step S3 undergoes an intermolecular Yamamoto coupling reaction under nickel catalysis to obtain the reaction precursor compound BBA. S5. Under the action of an oxidant, the precursor compound BBA described in step S4 undergoes an intramolecular oxidative dehydrogenation cyclization reaction to obtain the eight-membered ring fused fluoroboron dipyrrole compound.

4. The method for preparing the eight-membered ring fused fluoroboron dipyrrole compound according to claim 3, characterized in that, The specific process of step S1 is as follows: In a reaction flask, the 2,7-dibromoanthracene-9-carboxaldehyde, the 3,5-di-tert-butylphenylboronic acid, a base, an organic solvent, and water are added and mixed evenly to obtain a mixture; after the mixture is bubbled with nitrogen, a palladium complex containing a phosphine ligand is added, and a Suzuki coupling reaction is carried out at a temperature of 80-100 °C. The mixture after the reaction is extracted, distilled under reduced pressure, and subjected to column chromatography to obtain the 2-bromo-7-(3,5-di-tert-butylphenyl)anthracene-9-carboxaldehyde.

5. The method for preparing the eight-membered ring fused fluoroboron dipyrrole compound according to claim 4, characterized in that, The alkali is sodium carbonate, potassium carbonate, cesium carbonate, or potassium phosphate; And / or, the palladium complex containing the phosphine ligand is one of 1,1′−bis(diphenylphosphine)ferrocene palladium dichloride, tetra(triphenylphosphine) palladium, and 1,3−bis(diphenylphosphine)propane palladium dichloride; And / or, the organic solvent is at least one selected from 1,4-dioxane, tetrahydrofuran, toluene, and N,N-dimethylformamide; And / or, the molar ratio of 2,7-dibromoanthracene-9-carboxaldehyde to 3,5-di-tert-butylphenylboronic acid is 1:(0.8~1.2); the molar ratio of the base to 2,7-dibromoanthracene-9-carboxaldehyde is (1.5~3):1; the volume-to-mass ratio of the organic solvent to 2,7-dibromoanthracene-9-carboxaldehyde is 20 mL / g~100 mL / g; the volume ratio of water to the organic solvent is 1:(3~10); and the amount of the palladium complex containing the phosphine ligand is 0.5% to 5% of the molar amount of 2,7-dibromoanthracene-9-carboxaldehyde.

6. The method for preparing the eight-membered ring fused fluoroboron dipyrrole compound according to claim 3, characterized in that, The specific process of step S2 is as follows: In a reaction flask, 1-Boc-pyrrole-2-boronic acid, 3,5-di-tert-butylbromobenzene, a base, a palladium complex containing a phosphine ligand, and a mixed solvent of toluene and methanol are added and mixed evenly to obtain a mixture; after the mixture in the reaction flask is bubbled with nitrogen, the palladium complex containing a phosphine ligand is added, and a Suzuki coupling reaction is carried out at a temperature of 100-130 °C. The mixture after the reaction is extracted, distilled under reduced pressure, and subjected to column chromatography to obtain 2-(3,5-di-tert-butylphenyl)-1H-pyrrole.

7. The method for preparing the eight-membered ring fused fluoroboron dipyrrole compound according to claim 6, characterized in that, The alkali is sodium carbonate, potassium carbonate, cesium carbonate, or potassium phosphate; And / or, the palladium complex containing the phosphine ligand is one of 1,1′−bis(diphenylphosphine)ferrocene palladium dichloride, tetra(triphenylphosphine) palladium, and 1,3−bis(diphenylphosphine)propane palladium dichloride; And / or, the molar ratio of 1-Boc-pyrrole-2-boronic acid to 3,5-di-tert-butylbromobenzene is 1:(0.5~1.2), the molar ratio of the base to 3,5-di-tert-butylbromobenzene is (2~4):1, the amount of the palladium complex containing the phosphine ligand is 0.5%~5% of the molar amount of 3,5-di-tert-butylbromobenzene; and the volume ratio of toluene to methanol is (5~20):

1.

8. The method for preparing the eight-membered ring fused fluoroboron dipyrrole compound according to claim 3, characterized in that, The specific process of step S3 is as follows: In a reaction flask, 2-bromo-7-(3,5-di-tert-butylphenyl)anthracene-9-carboxaldehyde and an organic solvent are added. After bubbling with nitrogen, 2-(3,5-di-tert-butylphenyl)-1H-pyrrole and an acidic catalyst are added to carry out a condensation reaction to obtain a dipyrrole methane intermediate. The dipyrrole methane intermediate is oxidized under the action of an oxidant, and then undergoes a fluorination-boronization cyclization reaction with triethylamine and a boron trifluoride complex. The mixture after the reaction is subjected to vacuum distillation and column chromatography to obtain the reaction intermediate compound BA with a fluorinated boron dipyrrole structure.

9. The method for preparing the eight-membered ring fused fluoroboron dipyrrole compound according to claim 8, characterized in that, The acidic catalyst is at least one of trifluoroacetic acid, p-toluenesulfonic acid, boron trifluoride ether, and ferric chloride. And / or, the oxidant is selected from at least one of 2,3-dichloro-5,6-dicyano-1,4-benzoquinone, chloroquinone, and tetrachlorobenzoquinone; And / or, the boron trifluoride complex is at least one of boron trifluoride diethyl ether complex, boron trifluoride methanol complex, and boron trifluoride tetrahydrofuran complex; And / or, the reaction temperature of the condensation reaction is 10~40 °C; And / or, the oxidation reaction is carried out at a temperature of 10-40 °C for a time of 0.5-2 h; And / or, the molar ratio of 2-bromo-7-(3,5-di-tert-butylphenyl)anthracene-9-carboxaldehyde to 2-(3,5-di-tert-butylphenyl)-1H-pyrrole is 1:(2~2.5); the amount of acidic catalyst is 10%~50% of the molar amount of 2-bromo-7-(3,5-di-tert-butylphenyl)anthracene-9-carboxaldehyde; the molar ratio of the oxidant to 2-bromo-7-(3,5-di-tert-butylphenyl)anthracene-9-carboxaldehyde is... The molar ratio of triethylamine to 2-bromo-7-(3,5-di-tert-butylphenyl)anthracene-9-carboxaldehyde is (80-100):1; the molar ratio of boron trifluoride complex to 2-bromo-7-(3,5-di-tert-butylphenyl)anthracene-9-carboxaldehyde is (100-150):1; and the mass-volume ratio of organic solvent to 2-bromo-7-(3,5-di-tert-butylphenyl)anthracene-9-carboxaldehyde is 200 mL / g to 600 mL / g.

10. The method for preparing the eight-membered ring fused fluoroboron dipyrrole compound according to claim 3, characterized in that, The specific process of step S4 is as follows: In an inert gas atmosphere, a nickel catalyst, a nitrogen-containing ligand, and an olefinic co-ligand dissolved in an amide solvent are added to a reaction flask to carry out a catalyst activation reaction and obtain a catalytic system; then, the reaction intermediate compound BA described in step S3 is dissolved in an aromatic solvent and added dropwise to the catalytic system, and the temperature is raised to carry out an intermolecular Yamamoto coupling reaction; after the reaction is completed, the resulting reaction solution is diluted, washed, concentrated by vacuum distillation, and separated by column chromatography to obtain the reaction precursor compound BBA.

11. The method for preparing the eight-membered ring fused fluoroboron dipyrrole compound according to claim 10, characterized in that, The nickel catalyst is selected from at least one of bis(1,5-cyclooctadiene) nickel, bis(triphenylphosphine) nickel dichloride, and nickel acetylacetonate; And / or, the nitrogen-containing ligand is selected from at least one of 2,2'-bipyridine, 1,10-phenanthroline, N,N,N',N'-tetramethylethylenediamine and tris(2-pyridylmethyl)amine; And / or, the olefinic ligand is selected from at least one of 1,5-cyclooctadiene, 1,4-cyclooctadiene, norbornadiene, and cycloheptadiene; And / or, the amide solvent is selected from at least one of N,N-dimethylacetamide (DMA), N-methylpyrrolidone (NMP) and hexamethylphosphoric triamine (HMPA), and the aromatic solvent is selected from at least one of anhydrous toluene, anhydrous xylene, anhydrous ethylbenzene and anhydrous chlorobenzene; And / or, the catalyst activation reaction is carried out at a temperature of 50-60 °C for a reaction time of 20-40 min; And / or, the temperature of the intermolecular Yamamoto coupling reaction is 75-85 °C, and the reaction time is 3-5 h; And / or, the solvent used to dilute the reaction solution is ethyl acetate, and the reagents used to wash the organic phase are saturated ammonium chloride solution and saturated saline solution; And / or, the amount of nickel catalyst used is such that the molar ratio of compound BA is (1.2~2):1; the molar ratio of nitrogen-containing ligand to compound BA is (1.2~2):1; the molar ratio of olefinic co-ligand to compound BA is (1~2):1; the volume ratio of amide solvent to molar amount of compound BA is 100 mL / mmol~500 mL / mmol; the volume ratio of aromatic solvent to molar amount of compound BA is 100 mL / mmol~500 mL / mmol.

12. The method for preparing the eight-membered ring fused fluoroboron dipyrrole compound according to claim 3, characterized in that, The specific process of step S5 is as follows: Under an inert gas atmosphere, the precursor compound BBA is dissolved in a haloalkane solvent, and an iron(III) salt oxidant dissolved in a nitroalkane solvent is added dropwise at a low temperature of -5~5 ℃. The reaction is first carried out at a low temperature of -5~5 ℃, and then the temperature is raised to 10~40 ℃ to carry out an intramolecular oxidative dehydrogenation cyclization reaction. After the reaction is completed, the compound OBNG is obtained by quenching, extraction, vacuum distillation concentration, and column chromatography separation.

13. The method for preparing the eight-membered ring fused fluoroboron dipyrrole compound according to claim 12, characterized in that, The halocarbon solvent is at least one of dichloromethane, chloroform, and 1,2-dichloroethane; And / or, the nitroalkane solvent is at least one selected from nitromethane, 1-nitropropane, and 1-nitropropane; And / or, the iron(III) salt oxidant is selected from at least one of ferric tribromide, ferric sulfate, ferric chloride hexahydrate, and ferric nitrate; And / or, the quenching reagent is a saturated sodium bicarbonate solution, and the extraction solvent is dichloromethane; And / or, the molar ratio of the iron(III) salt oxidant to the compound BBA is (30~80):1; the volume molar ratio of the haloalkane solvent to the compound BBA is 200 mL / mmol~1000 mL / mmol; the volume molar ratio of the nitroalkane solvent to the compound BBA is 50 mL / mmol~500 mL / mmol.

14. The method for preparing the eight-membered ring fused fluoroboron dipyrrole compound according to claim 7, characterized in that, The 2,7-dibromoanthracene-9-carboxaldehyde described in step S1 is obtained through the following steps: P1, 5-bromo-2-methylbenzaldehyde and 1-bromo-4-iodobenzene were coupled via a palladium-catalyzed carbon-hydrogen bond activation reaction to give the precursor 5-bromo-2-(4-bromobenzyl)benzaldehyde; P2. The 5-bromo-2-(4-bromobenzyl)benzaldehyde described in step P1 undergoes Grignard reaction, Friedel-Crafts alkylation reaction and oxidative dehydrogenation reaction in sequence under the action of methyl magnesium bromide to give 2,7-dibromo-9-methylanthracene. P3. The 2,7-dibromo-9-methylanthracene described in step P2 is subjected to bromination, transesterification, alkaline hydrolysis, and Swern oxidation to obtain 2,7-dibromoanthracene-9-carboxaldehyde.

15. The method for preparing the eight-membered ring fused fluoroboron dipyrrole compound according to claim 14, characterized in that, The specific process of step P1 is as follows: 5-bromo-2-methylbenzaldehyde and 1-bromo-4-iodobenzene are reacted in a mixed solvent system of palladium(II) salt catalyst, silver salt promoter, nitrogen-containing ligand, and carboxylic acid solvent-water. After stirring, the mixture is heated to 85-95 °C to carry out a carbon-hydrogen bond activation coupling reaction. After the reaction, the resulting reaction solution is filtered, concentrated under reduced pressure, and separated by column chromatography to obtain 5-bromo-2-(4-bromobenzyl)benzaldehyde. The palladium(II) salt catalyst is selected from at least one of palladium acetate, palladium trifluoroacetate, and palladium chloride. The silver salt promoter is selected from at least one of silver trifluoroacetate, silver acetate, and silver carbonate. The nitrogen-containing ligand is at least one of glycine, N-acetylglycine, and proline. The carboxylic acid solvent is at least one of acetic acid, trifluoroacetic acid, and propionic acid. The specific process of step P2 is as follows: 5-bromo-2-(4-bromobenzyl)benzaldehyde is dissolved in an ether solvent, cooled to -5 ℃ to 10 ℃, and Grignard reagent is added to carry out a Grignard addition reaction. After the reaction is completed, water is added to quench the reaction, followed by extraction and concentration under reduced pressure to obtain the first crude product. The first crude product is dissolved in a haloalkanes solvent, cooled to -85 ℃ to -70 ℃, and an acidic catalyst is added to carry out a Friedel-Crafts alkylation reaction. The temperature is then raised to room temperature to continue the Friedel-Crafts alkylation reaction. After the reaction is completed, water is added to quench the reaction, followed by extraction, concentration under reduced pressure, and washing to obtain the second crude product. The second crude product and an oxidizing agent are dissolved in an aromatic solvent and heated to 95~105 ℃ to carry out an oxidative dehydrogenation reaction. After the reaction is completed, the solution is concentrated under reduced pressure and separated by column chromatography to obtain the 2,7-dibromo-9-methylanthracene. The specific process of step P3 is as follows: 2,7-dibromo-9-methylanthracene is dissolved in a halogenated alkane solvent with a brominating reagent and an initiator, and the temperature is raised to 85-95 °C for bromination. After the reaction, the mixture is concentrated under reduced pressure and separated by column chromatography to obtain 2,7-dibromo-9-(bromomethyl)anthracene. The 2,7-dibromo-9-(bromomethyl)anthracene is dissolved in an amide solvent with a potassium salt reagent and a phase transfer catalyst, and the temperature is raised to 95-105 °C for transesterification. After the reaction, a quenching reagent is added, followed by extraction, concentration under reduced pressure, and separation by column chromatography to obtain methyl (2,7-dibromoanthracene-9-yl) acetate. The methyl (2,7-dibromoanthracene-9-yl) acetate is dissolved in an alcohol solvent with a base reagent, and the temperature is raised to 75-85 °C for alkaline hydrolysis. After the reaction, the mixture is concentrated under reduced pressure, water is added, and the mixture is filtered to obtain (2,7-dibromoanthracene-9-yl)methanol. Oxaloyl chloride is dissolved in a halogenated alkane solvent and the temperature is lowered to -85 °C. After reaching -70 °C, dimethyl sulfoxide was added for reaction, followed by the addition of (2,7-dibromoanthracene-9-yl)methanol for Swern oxidation. Subsequently, an organic amine reagent was added to continue the reaction. After heating to room temperature, the mixture was concentrated, dissolved, washed, concentrated under reduced pressure, and separated by column chromatography to obtain the 2,7-dibromoanthracene-9-carboxaldehyde.

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