Open-shell aromatized free radical compound as well as preparation method and application thereof
By reacting compound (II) with boron tribromide and purifying it, an open-shell aromatic free radical compound with high solubility and good stability in a variety of solvents is prepared, which solves the problems of complex synthesis and poor stability in the existing technology and realizes its application in lithium-ion batteries, organic electronic spin devices and photothermal conversion materials.
Patent Information
- Application Number
- CN202510350835.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-24
- Publication Date
- 2025-09-23
AI Technical Summary
The synthesis steps of existing organic free radical compounds are complex, difficult, unstable, difficult to control, and difficult to dissolve in various solvents, which limits their application in functional materials.
The open-shell aromatic radical compound (I) is prepared by reacting compound (II) with boron tribromide in an organic solvent and purifying the resultant product by filtration, column chromatography and recrystallization.
The synthesis method is simple and has high yield. The obtained compound has good solubility in a variety of solvents, has photothermal conversion, electrochemical stability and paramagnetism, and is suitable for lithium-ion batteries, organic electronic spin devices and photothermal conversion materials.
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Figure CN120682076A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of organic free radical compounds, and in particular relates to an open-shell aromatized free radical compound and a preparation method and application thereof. Background Art
[0002] Organic free radical compounds are molecules or ions containing one or more unpaired electrons. Due to the presence of these unpaired electrons, these compounds often exhibit unique electronic structures and physicochemical properties. On the one hand, the unpaired electrons in their molecular orbitals impart infrared / near-infrared absorption, spin magnetism, and charge transport capabilities, enabling their use in the preparation of optical, electrical, and magnetic functional materials. On the other hand, the high reactivity imparted by the unpaired electrons makes the free radicals susceptible to decomposition or reaction with water, oxygen, and other environmental factors, reducing their chemical stability. Therefore, the synthesis methods and functional materials of organic free radical compounds have long been a hot topic of research in this field.
[0003] Organic semiconductor molecules are classified into "closed-shell" and "open-shell" types based on their electronic ground state. Open-shell radical semiconductor molecules, characterized by unpaired electrons, possess unique physical and chemical properties. They exhibit excellent solubility in common organic solvents such as methanol, ethanol, ethyl acetate, tetrahydrofuran, and dimethyl sulfoxide, offering significant advantages over traditional inorganic and polymer semiconductor materials for industrial applications.
[0004] We designed and synthesized an open-shell aromatic radical compound. This open-shell aromatic radical molecule has good photothermal conversion and magnetic properties, and can be used in lithium-ion batteries, organic electronic spin devices, photothermal conversion and other fields. Summary of the Invention
[0005] In view of this, in order to solve the technical problems in the prior art of organic free radical compound synthesis such as multiple steps, complex process, great difficulty, poor stability, and difficulty in control, the present invention provides an open-shell aromatized free radical compound and its preparation method and application.
[0006] The technical solutions adopted by the present invention to solve the above technical problems are as follows.
[0007] The present invention provides an open-shell aromatic free radical compound, the chemical structure of which is shown in formula (I): (Ⅰ).
[0008] The present invention also provides a method for preparing the above-mentioned open-shell aromatic free radical compound: dissolving compound (II) in an organic solvent, then adding boron tribromide, and causing a demethylation reaction under stirring at room temperature. After the reaction is completed, water is added to quench the reaction, and the mixture is purified by filtration, column chromatography, and recrystallization to obtain the open-shell aromatic free radical compound.
[0009] The chemical formula of the compound (II) is shown in formula (II): (Ⅱ).
[0010] Preferably, the organic solvent is dehydrated dichloromethane.
[0011] Preferably, the molar ratio of the compound (II) to boron tribromide is 1:(3-4).
[0012] Preferably, the reaction temperature of the oxidation reaction is 0-40° C., and the reaction time is 1-5 h.
[0013] The present invention also provides the use of the open-shell aromatic free radical compound in the preparation of lithium battery positive electrodes, organic electronic spin devices, and photothermal conversion materials.
[0014] Compared with the prior art, the present invention has the following beneficial effects:
[0015] 1. The open-shell aromatic free radical compound of the present invention has good solubility in a variety of solvents. The solubility of the open-shell aromatic free radical compound in ethyl acetate, ethanol, tetrahydrofuran, and dimethyl sulfoxide is greater than 1 mg / mL, which facilitates solution processing and device assembly.
[0016] 2. The open-shell aromatized free radical compound of the present invention has a conventional and easy-to-operate synthesis method, a high yield, and a convenient purification process, which is conducive to large-scale synthesis.
[0017] 3. Experimental tests have shown that the open-shell aromatic free radical compounds synthesized by the present invention have a wide range of solar light absorption properties and can be used to prepare photothermal conversion materials; the open-shell aromatic free radical compounds synthesized by the present invention have good electrochemical stability and can be used to prepare battery devices; the open-shell aromatic free radical compounds synthesized by the present invention exhibit obvious paramagnetic properties and can be used to prepare organic electronic spin devices. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.
[0019] Figure 1 is the NMR spectrum of compound (I).
[0020] Figure 2 is the NMR spectrum of compound (II).
[0021] Figure 3This is a diagram of the long cycle discharge specific capacity of the buckle battery of Example 4 of the present invention.
[0022] Figure 4 This is the electron spin resonance test spectrum of the open-shell aromatic free radical compound (I) of Example 1 of the present invention.
[0023] Figure 5 This is a diagram showing the photothermal conversion performance of the open-shell aromatic free radical compound (I) of Example 1 of the present invention. DETAILED DESCRIPTION
[0024] In order to further illustrate the present invention, preferred embodiments of the present invention are described below in conjunction with specific implementation methods. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention rather than limiting the patent requirements of the present invention.
[0025] The present invention provides an open-shell aromatic free radical compound, the chemical structure of which is shown in formula (I): (Ⅰ).
[0026] The preparation method of the open-shell aromatic free radical compound of the present invention comprises the following steps: dissolving a compound (II) in dehydrated dichloromethane, adding boron tribromide, wherein the molar ratio of the compound (II) to the boron tribromide is 1:(3-4), reacting the mixture under stirring at room temperature for 1-5 hours, quenching the mixture after filtration, and purifying the mixture by column chromatography to obtain the open-shell aromatic free radical compound represented by formula (I).
[0027] The terms used in the present invention generally have the meanings commonly understood by those skilled in the art, unless otherwise specified. In order to enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described in detail below with reference to the embodiments.
[0028] In the following examples, various processes and methods not described in detail are conventional methods known in the art. Unless otherwise specified, the materials, reagents, devices, instruments, equipment, etc. used in the following examples can be obtained from commercial sources.
[0029] Example 1
[0030] Preparation of open-shell aromatic free radical compounds (Ⅰ):
[0031] Step 1: 2-bromo-6-methoxynaphthalene (4.0 g, 16.53 mmol), 4,4'-dimethoxydiphenylamine (3.91 g, 16.53 mmol), sodium tert-butoxide (4.0 g, 41.62 mmol), tri-tert-butylphosphine tetrafluoroborate (0.03 g, 0.10 mmol), and bis(dibenzylideneacetonepalladium) (0.01 g, 0.01 mmol) were placed in a dry reaction flask. Diphenyl ether (20 mL) was added to fully dissolve the mixture. After vacuuming and purging with nitrogen for more than three times, the mixture was heated to 180°C and stirred for 3 hours. The reaction was complete when thin-layer chromatography showed the disappearance of the starting material. The resulting reaction mixture was cooled to room temperature and transferred to a separatory funnel. It was extracted three times with dichloromethane and deionized water to remove inorganic salts and catalyst. Subsequently, the crude product was purified by silica gel column chromatography (petroleum ether: dichloromethane = 3:1) to obtain 5.64 g of a yellow-green solid with a yield of 89%, which was recorded as compound (II).
[0032] The obtained compound (II) was subjected to 1H NMR analysis, and its NMR spectrum is shown in Figure 2 , where 1H NMR (400 MHz,CDCl3)δ7.56 (d, J =8.8 Hz, 1H),7.48–7.43(m, 1H),7.24–7.17(m, 2H),7.08–7.02(m,6H),6.84–6.80(m, 4H),3.89(s, 3H),3.80(s, 6H).
[0033] Step 2: Dissolve dried compound (IV) (3.59 g, 9.32 mmol) in dehydrated dichloromethane (20 mL) and mix with 25 mL of boron tribromide (50 mmol, 2 M in dichloromethane). Stir at room temperature for 5 hours to precipitate a solid product. Deionized water was then added dropwise to the reaction mixture to quench the boron tribromide. The solid was separated by filtration and washed with deionized water and then dichloromethane. The crude product was then purified by silica gel column chromatography (petroleum ether:ethyl acetate = 3:1). 2.32 g of a green solid was obtained with an 89% yield and was designated as compound (I).
[0034] The obtained molecule was subjected to 1H NMR analysis, and its NMR spectrum is shown in Figure 1, where 1H NMR (400 MHz, DMSO-d6)δ9.42(s, 1H),9.24 (s, 2H),7.51– 7.47(m, 1H),7.43(d, J =8.9 Hz, 1H),7.00–6.96(m, 3H),6.93(dd, J =8.8,2.4 Hz, 1H), 6.89–6.85 (m, 4H), 6.73–6.68 (m, 4H).
[0035] Example 2
[0036] Preparation of open-shell aromatic radical compound (IV):
[0037] Step 1: 2-bromo-6-methoxynaphthalene (202 mg, 0.84 mmol), 4,4'-dimethoxydiphenylamine (161 mg, 0.70 mmol), sodium tert-butoxide (325 mg, 3.37 mmol), tri-tert-butylphosphine tetrafluoroborate (49 mg, 0.17 mmol), and bis(dibenzylideneacetonepalladium) (20 mg, 0.04 mmol) were placed in a dry reaction flask. Toluene (16 mL) was added to fully dissolve the mixture. After three vacuum and nitrogen purging operations, the mixture was heated to 125°C and stirred for 3 hours. The reaction was complete when thin-layer chromatography showed the disappearance of the starting material. The resulting reaction mixture was cooled to room temperature and transferred to a separatory funnel. Dichloromethane and deionized water were added and extracted three times to remove inorganic salts and catalyst. Subsequently, the crude product was purified by silica gel column chromatography (petroleum ether: dichloromethane = 3:1) to obtain 263 mg of a yellow-green solid with a yield of 81.8%, which was designated as compound (III) with the structural formula shown in formula (II).
[0038] Step 2: Dissolve the dried compound (III) (97 mg, 0.25 mmol) as the precursor to be oxidized in dehydrated dichloromethane (5 mL) and dropwise add 0.3 mL of boron tribromide (3.17 mmol) solution. Stir at room temperature for 5 hours to precipitate a solid product. Deionized water was then added dropwise to the reaction mixture to quench the boron tribromide. The solid was separated by filtration and washed with deionized water and then dichloromethane. Finally, the product was dried at 60°C for 8 hours. This yielded 74 mg of a green solid, designated as compound (IV), with a yield of 76.1%.
[0039] Example 3.
[0040] Preparation of open-shell aromatic free radical compounds (VI):.
[0041] Step 1: 2-bromo-6-methoxynaphthalene (20.0 g, 84 mmol), 4,4'-dimethoxydiphenylamine (17.5 g, 74.8 mmol), sodium tert-butoxide (30.0 g, 312 mmol), tri-tert-butylphosphine tetrafluoroborate (4.0 g, 13.78 mmol), and bis(dibenzylideneacetonepalladium) (50 mg, 0.09 mmol) were placed in a dry reaction flask. Toluene (175 mL) was added to fully dissolve the mixture. After three vacuum and nitrogen purging operations, the mixture was heated to 125°C and stirred for 5 hours. The reaction was complete when thin-layer chromatography showed the disappearance of the starting material. The resulting reaction mixture was cooled to room temperature and transferred to a separatory funnel. Dichloromethane and deionized water were added and extracted three times to remove inorganic salts and catalyst. Subsequently, after rotary evaporation, the product was recrystallized using a petroleum ether / dichloromethane system to obtain 28.1 g of a yellow-green solid with a yield of 87.29%. The compound was designated as compound (V) and has the structural formula shown in formula (II).
[0042] Step 2: Dissolve the dried compound (V) (20 g, 51.89 mmol) as the precursor to be oxidized in dehydrated dichloromethane (160 mL). Add 15 mL of boron tribromide (158.7 mmol) dropwise to the mixture. Stir at room temperature for 7 hours to precipitate a solid product. Deionized water was then added dropwise to the reaction mixture to quench the boron tribromide. The solid was separated by filtration and washed with deionized water and then dichloromethane. Finally, the product was dried at 60°C for 8 hours. This yielded 14.61 g of a green solid, designated as Compound (VI), with an 82.0% yield.
[0043] Example 4
[0044] This embodiment provides the preparation of a lithium-ion battery pole piece containing the open-shell aromatic free radical material compound (I).
[0045] The compound (I) prepared in Example 1 and graphene oxide were weighed into a ball mill jar. After ball milling, polyvinylidene fluoride (PVDF) and N-methylpyrrolidone (NMP) were added and evenly mixed in a mortar. The mixed sample was coated on a current collector carbon-coated aluminum foil into a 500 μm thick film, vacuum dried at 80°C for 12 h, and the dried electrode film was cut into circular electrode pieces with a diameter of 12 mm to obtain the lithium-ion battery piece based on the open-shell aromatized free radical compound.
[0046] The ball milling conditions are as follows: 20 grinding balls with a diameter of 5 mm are added to the ball mill jar, the rotation speed is set to 300 r / min, the ball mill is rotated forward for 5 minutes, stopped for 5 minutes, and reversed for 5 minutes, and the ball milling is stopped after 60 minutes.
[0047] The mass ratio of the open-shell aromatic free radical material compound (I): graphene oxide: PVDF is 6:3:1.
[0048] The positive electrode sheet prepared in this example was assembled into a stainless steel / Li button cell, with Celgard 2500 as the separator and lithium-sulfur electrolyte as the electrolyte. The assembly order was negative electrode shell, spring, gasket, lithium sheet, separator, positive electrode sheet, and positive electrode shell. The assembled button cell was then subjected to room temperature rate charge and discharge tests. Figure 3 As shown, after 800 charge and discharge cycles at a current density of 200 mA / g, the capacity retention rate of the buckled electrode was 45.22%, and the coulombic efficiency remained at 100%. This indicates that the positive electrode containing the open-shell aromatic free radical material is relatively stable in lithium-ion batteries. After 300 charge and discharge cycles, the discharge specific capacity no longer decays, and the coulombic efficiency is high, demonstrating the potential of the open-shell aromatic free radical compound as a battery device material.
[0049] Electron paramagnetic resonance (ESR) analysis of the open-shell aromatic radical compounds (I), (IV) and (VI) synthesized in Examples 1, 2 and 3 revealed that all compounds (I), (IV) and (VI) exhibited electron spin signals. Figure 4 As shown, the g value is 2.0032, indicating the existence of a single electron in the radical. The significant paramagnetic properties indicate that the open-shell aromatic radical compound can be used to prepare organic spintronic device materials.
[0050] The photothermal conversion characteristics of the open-shell aromatic radical compounds (I), (IV) and (VI) synthesized in Examples 1, 2 and 3 were analyzed. 2 Under the irradiation of power, the maximum temperatures of compounds (I), (IV) and (VI) are 201.8℃, 188℃ and 197℃ respectively. Figure 5 As shown, at 0.8W / cm 2 Under high power irradiation, the temperature of compound (I) stabilized at around 150° C. after repeated heating and cooling. The rapid photothermal response and stable heating and cooling cycles indicate that the open-shell aromatic radical compound can be used to prepare photothermal conversion materials.
[0051] The implementation methods of the present invention are not limited to the above-mentioned embodiments. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principles of the present invention should be considered as equivalent replacement methods and are included in the scope of protection of the present invention.
Claims
1. An open-shell aromatized free radical compound, characterized in that: The chemical structure is shown in formula (I): (Ⅰ)。 2. The method for preparing an open-shell aromatized free radical compound according to claim 1, characterized in that: The precursor compound (II) to be oxidized is dissolved in an organic solvent, and boron tribromide is added to carry out a demethylation reaction under stirring at room temperature. After the reaction is completed, water is added to quench the reaction, the mixture is filtered, and the mixture is purified by column chromatography to obtain an open-shell aromatic free radical compound of formula (I). The chemical structure of the compound (II) is shown in formula (II): (Ⅱ)。 3. The method for preparing an open-shell aromatized free radical compound according to claim 2, wherein: The organic solvent is dehydrated dichloromethane.
4. The method for preparing an open-shell aromatized free radical compound according to claim 2, wherein: The molar ratio of the compound (II) to boron tribromide is 1: (3-4).
5. The method for preparing an open-shell aromatized free radical compound according to claim 2, characterized in that: The reaction temperature of the oxidation reaction is 0-40° C., and the reaction time is 1-5 hours.
6. Use of the open-shell aromatic radical compound according to claim 1 in preparing positive electrode sheets for lithium-ion batteries.
7. Use of the open-shell aromatic free radical compound according to claim 1 in organic spintronic devices and photothermal conversion.