A boron-sulfur doped fused ring aromatic containing a pyrrole ring, and a method of synthesis and use thereof

Abstract

The application discloses a pyrrole ring-containing boron-sulfur doped fused ring aromatic hydrocarbon and a synthesis method and application thereof, and relates to a pyrrole ring-containing boron-sulfur doped fused ring aromatic hydrocarbon which is synthesized from simple raw materials such as 2,6-difluoronitrobenzene through a Clauson-Kaas pyrrole synthesis reaction and an electrophilic boronation reaction. Property research involves ultraviolet, fluorescence and CV tests, and mercury ion tests. The application has the characteristics of a short reaction path, a simple operation method and mild reaction conditions, and the compound has the potential of application in the field of photoelectric devices and can also be applied to mercury ion identification.

Description

Technical Field

[0001] This invention relates to the synthesis and property study of boron-sulfur-doped fused-ring aromatic hydrocarbons containing pyrrole rings, particularly to a boronthioxazin compound, its synthesis method, and its applications. Sulfur atom-directed diborthioxazin is synthesized simply and rapidly from commercially available 2,6-difluoronitrobenzene and other simple starting materials via the Clauson-Kaas pyrrole synthesis reaction and electrophilic borylation reaction. Property studies included UV, fluorescence, and CV measurements, as well as mercury ion assays. This invention features a short reaction pathway, simple operation, and mild reaction conditions, and the compound has potential applications in optoelectronic devices. Background Technology

[0002] Polycyclic aromatic hydrocarbons (PAHs) are mostly arranged in π-π ordered stacking, giving them unique photoelectric physical properties. They are widely used in organic field-effect transistors (OFETs) (Wu W, Liu Y and Zhu D. π-Conjugated molecules with fusedrings for organic field-effect transistors: design, synthesis and applications[J]. Chemical Society Reviews. 2010, 39(5): 1489-1502), organic solar cells (OSCs) (Lin Y, Li Y and Zhan X. Small molecule semiconductors for high-efficiency organic photosvoltaics[J]. Chemical Society Reviews. 2012, 41(11): 4245-4272), and organic light-emitting diodes (OLEDs) (Forrest S R. The path to ubiquitous and low-cost organic electronic appliances on plastic[J]. Nature, 2004, 428: 911-918).

[0003] As the material basis for electronic components, the foundation for expanding the development of organic optoelectronic devices lies in designing and synthesizing organic semiconductor molecules with novel structures. During research, scientists discovered that introducing heteroatoms into conjugated systems can produce unique properties, leading to the emergence of various heteroatom-doped conjugated aromatic hydrocarbons, especially boron-doped polycyclic aromatic hydrocarbons (B-PHAs). The boron atom has an empty p orbital, allowing it to combine with other electron-rich heteroatoms, enabling charge transfer within the molecule. Therefore, it produces photoelectric physical properties completely different from those of all-carbon conjugated systems, thus significantly improving the performance of organic optoelectronic devices. Mikinori Ando .; Mika Sakai .; Naoki Ando .; Masato Hirai and Shigehiro Yamaguchi (Org. Biomol. Chem. 2019, 17, 5500-5504). It is worth noting that replacing C=C bonds with isoelectronic and isostructural BN bonds can develop different polycyclic aromatic hydrocarbons with different optical and electronic properties, while maintaining their spatial conformation almost identical to that of all-carbon compounds (Morgan, MM; Piers, W.E. Dalton. Trans. 2016, 45, 5920-5924).

[0004] Uralazine is a classic aza-16π-conjugated polycyclic aromatic hydrocarbon, first synthesized by Balli and Zeller in 1983 (Balli, H.; Zeller, M. Helv. Chim. Acta. 1983, 66, 2135-2139). Due to its unique structure and electronic properties, it has been extensively studied and its application potential in the optoelectronic field has been explored.

[0005] In boron-sulfur-doped aromatics, the lone pair of electrons on the sulfur atom and the empty p orbital on the boron atom interact, with the boron atom acting as an excellent electron acceptor and the sulfur atom as an excellent electron donor. Due to the difference in electronegativity, the boron-sulfur bond is polar. Boron-sulfur heterocyclic aromatics readily form intramolecular charge transfers, and in the π-conjugated system of polycyclic aromatics, the electron configuration of the polycyclic conjugated aromatics can be modulated through the P-π* interaction between the empty p orbital and π* orbital on the boron atom, exhibiting unique photoelectric physical properties. This characteristic has led to widespread interest in boron-sulfur-doped polycyclic aromatics and their derivatives in fields such as organic optoelectronics.

[0006] Dewar (FA Davis; MJS Dewar. J. Am. Chem. Soc. 1968, 90, 3511-3515.) and Williams (PJ Grisdale; JLR Williams. J. Org. Chem. 1969, 34, 1675-1677.) synthesized boron-thiohexacyclic aromatic hydrocarbons in the 1960s. Since 2010, Ashe (AD Rohr, M. M. Banaszak) has also synthesized these hydrocarbons. Holl, JWKampf, AJAshe, Organometallics, 2011, 30, 14, 3698-3700.; Martin (S. Yruegas, CD. Martin. Chem. Eur. J. 2016, 22, 18358-18361.; Su, X.; JJ Baker, CD. Martin. Chem. Sci. 2020, 11, 126-131.) synthesized benzene rings with boron-sulfur units using a ring-expansion method, providing a new approach for the embedding of boron-sulfur bonds into polycyclic aromatic hydrocarbon skeletons, but the photoelectric physical properties of the compounds were not thoroughly investigated. With the advancement of technology, convenient synthetic methods, and the discovery by scientists that boron doping can effectively modulate the photoelectric physical properties of aromatic systems, boron-containing polycyclic conjugated aromatic hydrocarbons have successfully attracted research interest. Their potential applications in electronic devices have been extensively studied, but their potential applications in luminescent materials have not yet been widely developed.

[0007] In summary, boron-nitrogen-doped polycyclic aromatic hydrocarbons can be used to synthesize a variety of novel conjugated structures by modifying the conjugated framework. The unique photoelectric properties and supramolecular characteristics of these structures have significant application value in organic optoelectronic materials, energy storage, field emission, and other fields. They also have potential applications in organic semiconductor devices (such as organic field-effect transistors (OFETs)). S Organic photovoltaic devices (OPV) S ) and organic light-emitting diodes (OLEDs) S The practical applications of this technology have also attracted attention. Due to its unique properties, it is of great significance for the future application of solar energy and the development of fields such as photocatalysis. Summary of the Invention

[0008] The purpose of this invention is to address the technical deficiencies in the prior art by providing a boron-sulfur-doped fused-ring aromatic hydrocarbon containing a pyrrole ring.

[0009] Another object of the present invention is to provide a method for synthesizing the boron-sulfur-doped fused-ring aromatic hydrocarbon containing the pyrrole ring.

[0010] Another object of the present invention is to provide the application of the boron-sulfur-doped fused-ring aromatic hydrocarbon containing the pyrrole ring.

[0011] The technical solution adopted to achieve the purpose of this invention is:

[0012] A boron-sulfur-doped fused-ring aromatic hydrocarbon containing a pyrrole ring, with the structural formula shown in Formula 1:

[0013]

[0014] R a and R b Each is independently hydrogen, deuterium, alkyl, alkoxy, cycloalkyl, ether, heterocyclic, phenyl, aryloxy, halogen, cyano, or a combination thereof; R c It can be hydrogen, deuterium, alkyl, alkoxy, cycloalkyl, ether, heterocyclic aryl, phenyl, aryloxy, or a combination thereof; Ar can be a benzene ring, thiophene ring, furan ring, pyrrole ring, pyridine ring, benzothiophene, benzofuran, benzopyrrole, benzopyridine, naphthyl ring, anthracene ring, phenaene, carbazole, pyrazinyl, triphenyl, tetraphenyl, pyrene, Linear or angled pentanebenzene, hexabenzene, indene, or fluorene, where m is an integer from 0 to 5 and n is an integer from 0 to 3.

[0015] In the above technical solution, its structural formula is one of the following:

[0016]

[0017]

[0018]

[0019]

[0020]

[0021]

[0022] In the above technical solution, the synthesis method includes the following steps:

[0023] Step 1: Compound 1 reacts with 2,5-dimethoxytetrahydrofuran via a Clauson-Kaas pyrrole synthesis reaction to yield compound 2, as shown in the following reaction formula:

[0024]

[0025] Step 2: Compound 2 is reacted with boron tribromide or boron trichloride via a hydroboration reaction to obtain the boron-sulfur-doped fused-ring aromatic hydrocarbon containing a pyrrole ring, as shown in the following reaction formula:

[0026] R is R a and / or R b ;

[0027] or:

[0028] R is R a and / or R b .

[0029] In the above technical solution, in step 1, the molar ratio of 2,6-dimethylthioaniline to 2,5-dimethoxytetrahydrofuran is 1.0 to 3.0, the reaction temperature is 110 to 130°C, and the solvent is a mixed solvent of glacial acetic acid and 1,2-dichloroethane.

[0030] In the above technical solution, in step 2, under an inert gas atmosphere, compound 2 and tetrabutylammonium iodide are dissolved in chlorobenzene, and triethylamine and boron trichloride are added sequentially. The mixture is heated and stirred at 135–200°C for at least 24 hours. After cooling to room temperature, RMgBr is added, where R is R a and / or R b As a preferred option, RMgBr is 2,4,6-trimethylphenyl magnesium bromide, and the mixture is stirred overnight at room temperature.

[0031] In the above technical solution, in step 2, under an inert gas protective atmosphere, compound 2 is dissolved in o-dichlorobenzene, boron tribromide is added, and the mixture is stirred and reacted at 180-200°C for at least 12 hours. Then, triethylamine is added, and the mixture is heated and stirred at 180-220°C for at least 24 hours. After cooling to room temperature, RMgBr is added, where R is R a and / or R b As a preferred option, RMgBr is 2,4,6-trimethylphenyl magnesium bromide, and the mixture is stirred overnight at room temperature.

[0032] In another aspect of the present invention, the boron-sulfur-doped fused-ring aromatic hydrocarbon containing pyrrole rings is used as a luminescent material or host material in optical or optoelectronic devices, and the boron-sulfur-doped fused-ring aromatic hydrocarbon containing pyrrole rings is used as an organic sensor.

[0033] In the above technical solutions, the optical or optoelectronic device includes organic light-emitting diodes, organic solar cells, or organic field-effect transistors.

[0034] In the above technical solution, the boron-sulfur-doped fused-ring aromatic hydrocarbon containing a pyrrole ring is used in mercury ion recognition.

[0035] In the above technical solution, the boron-sulfur-doped fused-ring aromatic hydrocarbon containing a pyrrole ring is dissolved in a dichloromethane solution. With increasing mercuric chloride concentration, the emission peak at 406 nm increases, accompanied by a redshift, and a new emission peak appears at 431 nm. Compared with the prior art, the beneficial effects of this invention are:

[0036] 1. The present invention employs an improved synthesis method that makes the reaction raw materials inexpensive and readily available, avoids the use of toxic reagents in the reaction process, and is simple and easy to implement. The compound has wide applications in the fields of organic light-emitting diodes, organic solar cells, organic field-effect transistors, organic lasers, and organic sensors.

[0037] 2. The boron-sulfur-doped fused-ring aromatic hydrocarbon containing a pyrrole ring described in this invention has an absorption wavelength of 366 nm, an emission wavelength of 406 nm, and an external quantum yield of 1.03% in dichloromethane solution. In practical applications, the target compound was tested using a mercury ion probe. The addition of mercury ions to the dichloromethane solution of the compound resulted in a significant change in emission, confirming that the target compound can be used for mercury ion recognition. Attached Figure Description

[0038] Picture 1 This is the 1H NMR spectrum of boron-sulfur-doped aromatic hydrocarbon 3.

[0039] Picture 2 This is the carbon NMR spectrum of boron-sulfur-doped aromatic hydrocarbon 3.

[0040] Picture 3 It is a single crystal structure of boron-sulfur-doped aromatic hydrocarbon 3.

[0041] Picture 4 This is the absorption spectrum of boron-sulfur-doped aromatic hydrocarbon 3.

[0042] Picture 5 It is the emission spectrum of boron-sulfur-doped aromatic hydrocarbon 3.

[0043] Picture 6 This is a comparison of the absorption and emission of boron-sulfur-doped aromatic hydrocarbons and boron-oxygen-doped aromatic hydrocarbons.

[0044] Picture 7 This is a comparison of the front-line orbitals of boron-sulfur-doped aromatics 3 and boron-oxygen-doped aromatics.

[0045] Picture 8 This is the emission spectrum of boron-sulfur-doped aromatic hydrocarbon 3 with different concentrations of mercury ions added to a dichloromethane solution. Detailed Implementation

[0046] The present invention will be further described in detail below with reference to specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0047] Example 1

[0048] A boron-sulfur-doped fused-ring aromatic hydrocarbon containing a pyrrole ring is prepared by the following method:

[0049] Step 1:

[0050]

[0051] 2,6-Dimethylthioaniline (114.9 mg, 0.62 mmol, 1.00 equiv), 2,5-dimethoxytetrahydrofuran (122.8 mg, 0.93 mmol, 1.50 equiv), and 1,2-dichloroethane (10 mL) were added sequentially to a 100 mL pear-shaped flask. Glacial acetic acid (5.00 mL) was added as a solvent. The system was heated and stirred at 118 °C for 6 hours. After the reaction was complete as detected by TLC, the mixture was filtered to obtain a brownish-yellow filtrate. The filtrate was extracted three times with water and dichlorotoluene. The lower organic phase was collected and dried over anhydrous sodium sulfate. After filtration and evaporation, a colorless oily crude product was obtained. Column chromatography was performed using PE:EA = 15:1 as eluent. Compound 2 was given in 82% yield as a white solid (120.2 mg). 1 H NMR (400MHz, CDCl3): δ7.38 (t, J = 8.0 Hz, 1H, Ar), 7.03 (d, J = 8.0 Hz, 2H, Ar), 6.68–6.70 (m, 2H, Ar), 6.42–6.44 (m, 2H, Ar), 2.36 (s, 6H, SCH3).

[0052] Step 2:

[0053]

[0054] Compound 2 (92.40 mg, mmol, 1.00 equiv) and tetrabutylammonium iodide (355.30 mg, 0.96 mmol, 2.40 equiv) were added to a dry 35 mL sealed tube. The system was placed in a glove box and the atmosphere was evacuated three times. Anhydrous chlorobenzene (5.00 mL), boron tribromide (318.00 mg, 1.30 mmol, 3.00 equiv), and triethylamine (160.60 mg, 1.60 mmol, 4.00 equiv) were added to the system inside the glove box. The system was heated and stirred at 135 °C for 24 hours. After cooling to room temperature, 2,4,6-trimethylmethylmagnesium bromide (1.0 M in THF, 4.86 mL, 4.86 mmol, 12.00 equiv) was added to the system inside the glove box, and the reaction was stirred at room temperature for 12 hours. After the reaction was complete as detected by TLC, the mixture was extracted three times with water and dichlorotoluene. The lower organic phase was collected, dried over anhydrous sodium sulfate, filtered, and evaporated to dryness to obtain a yellow, oily crude product. Column chromatography was performed using PE:EA = 20:1 eluent. Compound 3 was given in 26% yield as a yellow-green solid (47.4 mg). 1H NMR (400MHz, CDCl3): δ7.70(d,J=8.0Hz,2H,Ar),7.23(t,J=8.0Hz,1H,Ar),6.93(s,6H,Ar),2.36(s,6H,CH3),2.27(s,12H,CH3).

[0055] Example 2

[0056] A boron-sulfur-doped fused-ring aromatic hydrocarbon containing a pyrrole ring is prepared by the following method:

[0057] Step 1 is the same as in Example 1;

[0058] Step 2:

[0059]

[0060] Compound 2 (92.4 mg, mmol, 1.00 equiv) was added to a dry 35 mL sealed tube. The system was placed in a glove box and evacuated three times. In the glove box, 5.00 mL of anhydrous o-dichlorobenzene was added as a solvent, followed by boron tribromide (318.0 mg, 1.3 mmol, 3.00 equiv). The system was heated and stirred at 180 °C for 18 hours. After cooling to room temperature, triethylamine (160.6 mg, 1.6 mmol, 4.00 equiv) was added in the glove box, and the system was heated and stirred at 180 °C for 24 hours. After cooling to room temperature, 2,4,6-trimethylmethylmagnesium bromide (1.0 M in THF, 4.68 mL, 4.68 mmol, 12.00 equiv) was added in the glove box, and the reaction was stirred at room temperature for 12 hours. After the reaction was complete as detected by TLC, the mixture was extracted three times with water and dichlorotoluene. The lower organic phase was collected, dried over anhydrous sodium sulfate, filtered, and evaporated to dryness to obtain a yellow, oily crude product. Column chromatography was performed using PE:EA = 30:1 as eluent. Compound 3 was given in 22% yield as a yellow solid (39.8 mg).

[0061] Example 3

[0062] This embodiment verifies the photoelectric properties of compound 3.

[0063] To further investigate the photoelectric physical properties of this compound, we characterized it using UV absorption and fluorescence emission tests, and performed frontier orbital calculations. Compound 3 was tested at room temperature in anhydrous dichloromethane (concentration 1×10⁻⁶). -5In M), the maximum absorption wavelength is reached at 365 nm, while the maximum emission wavelength is reached at 406 nm, with a fluorescence quantum yield of 1.03%. In frontier orbit calculations, the structure was optimized using the B3LYP / 6-31G(d) series basis sets and methods. Then, using these basis sets and methods, the frontier orbit was calculated. Comparison with boron-oxygen-doped fused-ring aromatic hydrocarbons containing pyrrole rings yielded the conclusion of a narrower bandgap, corresponding to the redshift phenomenon in photophysical measurements. This lays the foundation for the application of boron-sulfur-doped fused-ring aromatic hydrocarbons containing pyrrole rings in optoelectronic materials.

[0064] Example 4

[0065] Application of compound 3 as a mercury ion probe.

[0066] Compound 3 was dissolved in dichloromethane solution to prepare a solution of 1×10⁻⁶. -3 The mother liquor of M was prepared by using a microsyringe to sequentially take different amounts of the mother liquor and dichloromethane solution, and then add different amounts of mercuric chloride solution to prepare a 1×10⁻⁶ solution. -5 A solution of M. For example... Picture 8 As shown, with the increase of mercuric chloride concentration, the emission peak at 406 nm increases, accompanied by a redshift, and a new emission peak appears at 431 nm.

[0067] The above description is only a preferred embodiment of the present invention. It should be noted that, for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. Use of boron-sulfur doped fused ring aromatic hydrocarbons containing a pyrrole ring for the recognition of mercury ions, characterized in that, The structural formula of the pyrrole ring-containing boron-sulfur doped fused ring aromatic hydrocarbon is: 。 2. Use of the pyrrol ring containing boron and sulfur doped fused ring aromatic hydrocarbon of claim 1 in mercury ion recognition, characterized in that, With the increase of the concentration of mercuric chloride, the emission peak at 406 nm is increased, accompanied by red shift phenomenon, and a new emission peak at 431 nm appears.

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